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Posts Tagged ‘cancer therapeutics’


New Type of Killer T-Cell

Reporter: Irina Robu, PhD

Scientists at Cardiff University have revealed a new type of killer T-cell which offers hope of a “one-size-fits-all” cancer therapy. Cancer-targeting via MR1-restricted T-cells is a thrilling new frontier, it increases the prospect of a ‘one-size-fits-all’ cancer treatment; a single type of T-cell that could be proficient of destroying numerous different types of cancers across the population.

T-cell therapies for cancer anywhere immune cells are removed, modified and returned to the patient’s blood to seek and destroy cancer cells – are the latest paradigm in cancer treatments. The most extensively-used therapy, known as CAR-T (Chimeric Antigen Receptor T-cell therapy) encompasses genetic modification of patient’s autologous T-cells to express a CAR specific for a tumor antigen, subsequent by ex vivo cell expansion and re-infusion back to the patient. The therapy is personalized to each patient, but targets only a few types of cancers.

Currently, Cardiff academics discovered T-cells equipped with a new type of T-cell receptor (TCR) which recognizes and kills most human cancer types, while ignoring healthy cells. This new TCR distinguishes when a molecule is present on the surface of a wide range of cancer cells and is able to distinguish between cancerous and healthy cells. Normal T-cells scans the surface of other cells to find anomalies and eliminate cancerous cells, yet ignores cells that contain only normal proteins.

The researchers at Cardiff was published in Nature Immunology, labels a unique TCR that can identify various types of cancer via a single HLA-like molecule called MR1 which varies in the human population. HLA differs extensively between individuals, which has previously prevented scientists from creating a single T-cell-based treatment that targets most cancers in all people. To investigate the therapeutic potential of these cells in vivo, the investigators injected T-cells able to identify MR1 into mice bearing human cancer and with a human immune system.

The Cardiff group were able to demonstrate that T-cells of melanoma patients modified to express this new TCR could destroy not only the patient’s own cancer cells, but also other patients’ cancer cells in the laboratory, irrespective of the patient’s HLA type. Experiments are under way to regulate the exact molecular mechanism by which the new TCR differentiates between healthy cells and cancer.

Source

https://www.eurekalert.org/pub_releases/2020-01/cu-don012020.php

 

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37th Annual J.P. Morgan HEALTHCARE CONFERENCE: News at #JPM2019 for Jan. 8, 2019: Deals and Announcements

Reporter: Stephen J. Williams, Ph.D.

From Biospace.com

JP Morgan Healthcare Conference Update: FDA, bluebird, Moderna and the Price of Coffee

Researcher holding test tube up behind circle of animated research icons

Tuesday, January 8, was another busy day in San Francisco for the JP Morgan Healthcare Conference. One interesting sideline was the idea that the current government shutdown could complicate some deals. Kent Thiry, chief executive officer of dialysis provider DaVita, who is working on the sale of its medical group to UnitedHealth Group this quarter, said, “We couldn’t guarantee that even if the government wasn’t shut down, but we and the buyer are both working toward that goal with the same intensity if not more.”

And in a slightly amusing bit of synchrony, U.S.Food and Drug Administration (FDA)Commissioner Scott Gottlieb’s keynote address that was delivered by way of video conference from Washington, D.C., had his audio cut out in the middle of the presentation. Gottlieb was talking about teen nicotine use and continued talking, unaware that his audio had shut off for 30 seconds. When it reconnected, the sound quality was reportedly poor.

Click to search for life sciences jobs

bluebird bio’s chief executive officer, Nick Leschlygave an update of his company’s pipeline, with a particular emphasis on a proposed payment model for its upcoming LentiGlobin, a gene therapy being evaluated for transfusion-dependent ß-thalassemia (TDT). The gene therapy is expected to be approved in Europe this year and in the U.S. in 2020. Although the price hasn’t been set, figures up to $2.1 million per treatment have been floated. Bluebird is proposing a five-year payment program, a pledge to not raise prices above CPI, and no costs after the payment period.

Eli Lilly’s chief executive officer David Ricks, just days after acquiring Loxo Oncologyoffered up projections for this year, noting that 45 percent of its revenue will be created by drugs launched in 2015. Those include Trulicity, Taltz and Verzenio. The company also expects to launch two new molecular entities this year—nasal glucagons, a rescue medicine for high blood sugar (hyperglycemia), and Lasmiditan, a rescue drug for migraine headaches.

CNBC’s Jim Cramer interviewed Allergan chief executive officer Brent Saunders, in particular discussing the fact the company’s shares traded in 2015 for $331.15 but were now trading for $145.60. Cramer noted that the company’s internal fundamentals were strong, with multiple pipeline assets and a strong leadership team. Some of the stock problems are related to what Saunders said were “unforced errors,” including intellectual property rights to Restasis, its dry-eye drug, and Allergan’s dubious scheme to protect those patents by transferring the rights to the Saint Regis Mohawk Tribe in New York. On the positive side, the company’s medical aesthetics portfolio, dominated by Botox, is very strong and the overall market is expected to double.

One of the big areas of conversation is so-called “flyover tech.” Biopharma startups are dominant in Boston and in San Francisco, but suddenly venture capital investors have realized there’s a lot going on in between. New York City-based Radian Capital, for example, invests exclusively in markets outside major U.S. cities.

“At Radian, we partner with entrepreneurs who have built their businesses with a focus on strong economics rather than growth at all costs,” Aly Lovett, partner at Radian, told The Observer. “Historically, given the amount of money required to stand up a product, the software knowledge base, and coastal access to capital, health start-ups were concentrated in a handful of cities. As those dynamics have inverted and as the quality of living becomes a more important factor in attracting talent, we’re not seeing a significant increase in the number of amazing companies being built outside of the Bay Area.”

“Flyover companies” mentioned include Bind in Minneapolis, Minnesota; Solera Health in Phoenix, Arizona; ClearDATA in Austin, Texas; Healthe, in Eden Prairie, Minnesota; HistoSonics in Ann Arbor, Michigan; and many others.

Only a month after its record-breaking IPO, Moderna Therapeutics’ chief executive officer Stephane Bancelspent time both updating the company’s clinical pipeline and justifying the company’s value despite the stock dropping off 26 percent since the IPO. Although one clinical program, a Zika vaccine, mRNA-1325, has been abandoned, the company has three new drugs coming into the clinic: mRNA-2752 for solid tumors or lymphoma; mRNA-4157, a Personalized Cancer Vaccine with Merck; and mRNA-5671, a KRAS cancer vaccine. The company also submitted an IND amendment to the FDA to add an ovarian cancer cohort to its mRNA-2416 program.

One interesting bit of trivia, supplied on Twitter by Rasu Shrestha, chief innovation officer for the University of Pittsburgh Medical Center, this year at the conference, 33 female chief executive officers were presenting corporate updates … compared to 19 men named Michael. Well, it’s a start.

And for another bit of trivia, Elisabeth Bik, of Microbiome Digest, tweeted, “San Francisco prices are so out of control that one hotel is charging the equivalent of $21.25 for a cup of coffee during a JPMorgan conference.”

Other posts on the JP Morgan 2019 Healthcare Conference on this Open Access Journal include:

#JPM19 Conference: Lilly Announces Agreement To Acquire Loxo Oncology

36th Annual J.P. Morgan HEALTHCARE CONFERENCE January 8 – 11, 2018

37th Annual J.P. Morgan HEALTHCARE CONFERENCE: #JPM2019 for Jan. 8, 2019; Opening Videos, Novartis expands Cell Therapies, January 7 – 10, 2019, Westin St. Francis Hotel | San Francisco, California

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AACR2016 – Cancer immunotherapy

Curator: Larry H. Bernstein, MD, FCAP

LPBI

 

AACR 2016: Cancer Immunotherapy and Beyond

At this year’s meeting there was a palpable buzz around subjects ranging from microbiomics to the tumor microenvironment and cancer vaccines, big data to in vitro and in vivo modeling and drug delivery (to name just a few).

By all accounts, this year’s American Association of Cancer Research’s 2016 annual meeting (AACR) was dominated by immunotherapy writ large. Which is not to say the meeting was devoid of other topics – there was certainly palpable buzz around subjects ranging from microbiomics to the tumor microenvironment and cancer vaccines, big data to in vitro and in vivo modeling and drug delivery (to name just a few), that kept the meeting’s 19,500 attendees rapt in New Orleans April 16-20. Yet in the 12-13 years that David R. Soto-Pantoja, Ph.D., has been attending AACR, the Wake Forest University School of Medicine assistant professor of Cancer Biology has “never seen anything take over so much like immunotherapy.”

That being said, it’s not always easy to put cancer research into neat little boxes. Researchers interested in cell signaling, and oncologists concerned with genomics, may have found themselves in sessions dedicated to finding and exploiting neo-antigens (one of immunotherapy’s buckets).

Immunotherapy Buckets

For years there have been certain pillars used to target cancer: chemotherapy, surgery, radiation therapy, and more recently targeted therapies. “And now immunotherapy,” says Wafik El-Deiry, M.D., Ph.D., Deputy Director for Translational Research at the Fox Chase Cancer Center. “This is an emerging and expanding field that is going to be very intensely explored in every direction you can imagine. I wouldn’t even try to pretend that we know what all the buckets are at this point.”

One known bucket that  isfast being filled is the area of checkpoint inhibitors (checkpoint blockades). Over the past few years several therapeutics have been developed that had to do with getting the immune system to either better recognize, better target, or better fight, a tumor, with some success. Recall that last year former president Jimmy Carter, earlier diagnosed with metastatic melanoma, was declared “cancer free” following treatment with radiation and an antibody targeted against the immune programmed cell death – 1 (PD-1) antigen. PD-1 keeps the immune cells in check; blockading PD-1 de-inhibits, or “releases the brakes” of these cells and allow them free rein to attack the cancer. Encouraging results from several trials and follow-ups of PD-1 and other checkpoint inhibitors, such as anti-PDL-1 and anti-CTLA-4, were presented. These are in some cases being combined for even greater efficacy.

In addition to trials, “a lot of people, whether in posters or in other smaller talks, delve into the scientific mechanism at the cellular and immunological level of how those worked,” remarked Emil Lou, M.D., Ph.D., assistant professor of Medicine in the Division of Hematology, Oncology and Transplantation at the University of Minnesota.

Another bucket  receiving many contributions is the area of CAR-T cells: T cells imbued with a chimeric antigen receptor. T cells that have been harvested from a patient are given a receptor that will recognize a new protein – CD-19, found on B cells, for example – expanded, and re-infused (adoptively transferred) back into the patient to attack the cancer — B cell lymphomas, in the present example. There were many hurdles and pitfalls to be overcome – from finding the right antigen and designing the CAR, to controlling the CAR-T cell’s response – yet the field “has gone at such a rapid pace that it’s very clinically relevant,” says Dr. Lou.

Much familiar (and not-so-familiar) technology, such as high content (phenotypic) screening platforms like the IntelliCyt, is being leveraged to help with array testing, selection, and even manufacturing of CAR-T cells, says Janette Phi, the company’s CBO.

Miltenyi Biotec touted their CliniMACS Prodigy, a benchtop-sized automated cell processing and separation platform, for manufacturing CAR-T cells. It can take a patient’s cells from apheresis and selection on beads, through viral transduction to final product “in 8-10 days,” says clinical instrument specialist Kevin Longin. “It’s a GMP lab without a GMP lab.”

But making bespoke CAR-Ts is a “very expensive approach,” notes Dr. Soto-Pantoja. There were discussions at the meeting about generating off-the-shelf CAR-T cells.

Gene Editing

One way to do this is to use gene editing techniques such as CRISPR/Cas9 to knock out the proteins that could cause rejection of these foreign cells by the patient’s own immune system, or graft-versus-host disease (in which the introduced cells treat the host as foreign).

CRISPR has really become a hot buzz word, says Dr. Lou. “More from the basic science side, and slowly making its way into the clinical talks – it’s not ready for prime time.” While gene editing spins off a different conversation about ethics – people are hesitant about its capacity to create designer babies — he notes that “in cancer it’s helpful to be able to study and reproduce the genes that are driving cancer, in the lab.”

CRISPR is not just for knocking genes in or out, either. In his plenary talk, MIT’s W. M. Keck Career Development Professor of Biomedical Engineering Feng Zhang, Ph.D., discussed a host of other uses to which his lab and others have put the CRISPR/Cas9 system and its relatives. They can be used to create selective transcriptional activation or repression, for example, to recruit epigenetic writers, erasers, and readers, to edit RNA transcripts, and even to identify non-coding regions of the genome.

Neo-antigens and Other Biomarkers

Gene therapy and gene editing are not the only ways in which the complement of expressed proteins is altered. Among the hallmarks of cancer is genetic mutation of oncogenes, tumor suppressor genes, and others – whether as point mutations, duplications, insertions and deletions (indels), or fusions. Because they’re mutated and encode other amino acids, they are “foreign” and may be recognized by the immune system as such, Dr. El-Deiry points out. “One needs to analyze these neo-antigens — to figure out what they are – as well as to analyze the various immune cell subsets that may react with those neo-antigens.” There are many tools that researchers are using to do just that, and there was no shortage of vendors from instrument and assay manufacturers and software developers to service providers – in areas like next-generation genomic sequencing (for both genomics and transcriptomics) and its associated preparatory and analytics, flow cytometry, and antibody development, to name just a few – vying for the attention of AACR conventioneers.

Neo-antigens are, of course, only one mark of a cancerous cell or tissue. In fact, most biomarkers used to diagnose or track cancers in the lab or the clinic rely on “signatures” — collections of multiple markers, each of which in and of themselves may be considered within the normal range but taken together (at the levels expressed) correlate with disease, prognosis, or likely response to treatment. Many panels, available on different platforms, are currently approved for clinical testing and others are working toward that goal.

It’s important to realize that cancers are often not static – they evolve, often as the result of treatment, sometimes selecting for a resistant population. “We’re trying to overcome the mistake of treating a patient’s cancer, after their tumor has grown despite different types of chemotherapies, based on what the information was at the time of diagnosis, when in reality the tumor has potentially transformed into something different,” relates Dr. Lou. Serial biopsies under the auspices of clinical trials, mostly in lung cancer, have revealed the evolution of cancer genomics and an understanding of how to better target therapy to the patient’s tumor at the time of recurrence and progression.

But taking a biopsy is an invasive and sometimes risky procedure.

Liquid Biopsy

It has been known for many years that cells, nucleic acids, and even vesicles derived from tumors can be found in blood and other fluids. “The idea that we can biopsy less invasively by using blood-based biomarkers is really coming to maturity just in the last two years or so,” says Dr. Lou. There is currently a lot of excitement about the possibility of using these as liquid biopsies to “provide a window into the cancer,” says Shane Booth, D. Phil., CTO of Angle LLC. They can look for the presence or evolution of a tumor, for example to monitor the effect of therapy.

Only a single circulating tumor cell (CTC) platform, CELLSEARCH, has thus far been approved for clinical use. Dr. Booth estimates that there are currently perhaps 20-30 different companies with technologies to isolate CTCs, most (like CELLSEARCH) based on affinity capture or (like Angle’s Parsortix platform) on “very sophisticated, bleeding-edge filtration techniques”. These differ from each other in a variety of ways including whether the platform performs analysis, whether it is specific or agnostic to the type of cancer, whether cells can be recovered (and whether they can be recovered alive) for downstream use, the purity of CTCs, and the sample preparation required.

Several companies are offering platforms or services to look at cell free DNA (cfDNA, aka circulating tumor DNA, ctDNA). Trovagene, for example, has assays to examine DNA in blood or urine for common BRAF, KRAS, and EGFR mutations. Meanwhile Nanostring Technologies uses digital molecular barcoding to multiplex hundreds of assays from single molecules without amplification.

Caris Life Sciences’ ADAPT Biotargeting System can profile the different proteins, miRNAs, and DNA found in exosomes. “It’s still early times, but these kinds of test will in the future be used to try and make some predictions about prognosis or response to therapy,” says Dr. El-Deiry.

Personalized Medicine

If there was a theme (implicitly) pervading AACR 2016 more than that of immunotherapy it was that of personalized medicine (aka precision medicine, individualized medicine). From genomic sequencing to determine whether a patient will benefit from (or be harmed by) a given therapy, to examining the microenvironment in which a tumor is found, one size no longer fits all.

The challenge, notes Dr. Soto-Pantoja, is to take the results seen in cases such as checkpoint inhibitor therapy, in which about one third of patients are seen to benefit, and figure out how to extend that to other patients and apply that to other types of cancer.

 

 

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Advances in Cancer Immunotherapy

Larry H. Bernstein, MD, FCAP, Curator

LPBI

 

Dramatic remissions in blood cancer in immunotherapy treatment trial

“We are at the precipice of a revolution in cancer treatment based on using immunotherapy.” — Stanley Riddell, MD

Recent advances in an immune-cell cancer treatment — a type of immunotherapy* using engineered immune cells to target specific molecules on cancer cells — are producing dramatic results for people with cancer, according to Stanley Riddell, MD, an immunotherapy researcher and oncologist at Seattle’s Fred Hutchinson Cancer Research Center.**

Riddell and his colleagues have refined new methods of engineering a patient’s own immune cells to better target and kill cancer cells while decreasing side effects. In laboratory and clinical trials, the researchers are seeing “dramatic responses” in patients with tumors that are resistant to conventional high-dose chemotherapy, “providing new hope for patients with many different kinds of malignancies,” Riddell said.

https://youtu.be/6mt7AyepE74?list=PLFb_Mc_opwOHti4qsYXvZWhXWvk41Wf9_

Twenty-seven out of 29 patients with an advanced blood cancer who received experimental, “living” immunotherapy as part of a clinical trial experienced sustained remissions, in preliminary results of an ongoing study at Fred Hutchinson Cancer Research Center.

Boosting natural immune response

Adoptive T-cell transfer aims to boost a patient’s immune cells’ ability to recognize and attack cancer cells. (1) T cells are extracted from the patient’s blood, (2) genetically engineered to produce a molecule that recognizes cancer cells and grown in the laboratory, and (3) infused back into the patient to (4) improve immune response. (credit: LUNGevity Foundation)

The immune system produces two major types of immune reaction to protect the body: one uses antibodies secreted by B cells; the other uses T cells.

Riddell’s team takes T cells from the patient’s body, re-engineers them, and infuses them back into the patient to create an army of cancer-fighting immune cells. (credit: Fred Hutchinson Cancer Research Center)

http://www.kurzweilai.net/images/T-cells.jpg

T cells are white blood cells that detect foreign or abnormal cells — including cancerous or infected cells — and initiate a process that targets those cells for attack. But the natural immune response to a tumor is often neither potent nor persistent enough, so Riddell and associates pioneered a new way to boost this immune response using a method known as “adoptive T-cell transfer.”

With adoptive T-cell transfer, immune cells are engineered to recognize and attack the patient’s cancer cells. Researchers extract T cells from a patient’s blood and then introduce genes into those T cells so they synthesize highly potent receptors (called chimeric antigen receptors, or CARs) that can recognize and target the cancer cell.

http://www.kurzweilai.net/images/20-million-T-cells.jpg

A single treatment of a relatively small number of the re-engineered T cells only takes about 30 minutes, and within weeks, the patient goes into a complete remission. (credit: Fred Hutchinson Cancer Research Center)

They grow the T cells in a laboratory for about two weeks and then infuse the engineered cells back into the patient, where they can home in on the tumor site and destroy the cancer cells.

Sustained remission of B cell cancers

Riddell’s team has recently developed a refined version of this process that increases the effectiveness of the immune response while reducing negative side effects, such as neurological symptoms, fevers, and large decreases in blood pressure.

In a study published in the journal Nature Biotechnology, Riddell and his team describe tagging the potent T-cell receptor (with amino acid sequences called Strep-tag), and the resulting effect on human cancer cells in the laboratory and on a mouse model of lymphoma.

Those results, using the latest version of this experimental immunotherapy, suggest sustained remission in cases of B cell cancers that previously relapsed and had become resistant to treatment.***

“The results are simply astounding,” Riddell said. We are treating patients with advanced leukemia and lymphoma that have failed every conventional therapy and radiation therapy, including transplants … in a single treatment. Within weeks, the patient goes into remission.”

“In my years as a oncologist and as a research scientist, I have never seen a treatment that has that spectacular response rate in its initial testing in patients,” Riddell said. His team is initiating trials in lung, breast, sarcoma, melanoma, and soon in pancreatic cancer. The opportunities for this technology are “incredible” and the approach has the potential to also treat common cancers such as kidney and colon cancer, he said.

“We are at the precipice of a revolution in cancer treatment based on using immunotherapy.”

Funding for Riddell’s research was provided by Juno Therapeutics.

* For approximately 100 years, the main tools to treat cancer were surgery, chemotherapy, and radiation therapy. But since around 2000, doctors have had access to a type of immunotherapy based on engineered antibodies that can target specific molecules on cancer cells. For example, trastuzumab (Herceptin) can be used for some types of breast cancer and stomach cancer. The new treatment approach used by Riddell’s team is based on a new type of immunotherapy using engineered immune cells to kill cancer, rather than antibodies.

** Stanley Riddell. Engineering T cells for safe and effective cancer immunotherapy. 2016 Annual Meeting of the American Association for the Advancement of Science, Washington, D.C., February 2016.

*** Such as acute lymphoblastic leukemia, Non-Hodgkin lymphoma, and chronic lymphocytic leukemia.


Abstract of Acquisition of a CD19 negative myeloid phenotype allows immune escape of MLL-rearranged B-ALL from CD19 CAR-T cell therapy

Administration of lymphodepletion chemotherapy followed by CD19-specific chimeric antigen receptor (CAR)-modified T cells is a remarkably effective approach to treat patients with relapsed and refractory CD19+ B cell malignancies. We treated 7 patients with B-cell acute lymphoblastic leukemia (B-ALL) harboring rearrangement of the mixed lineage leukemia (MLL) gene with CD19 CAR-T cells. All patients achieved complete remission in the bone marrow by flow cytometry after CD19 CAR-T cell therapy; however, within one month of CAR-T cell infusion two of the patients developed acute myeloid leukemia that was clonally related to their B-ALL, a novel mechanism of CD19-negative immune escape. These reports have implications for the management of patients with relapsed and refractory MLL-B-ALL who receive CD19 CAR-T cell therapy.


Abstract of Inclusion of Strep-tag II in design of antigen receptors for T-cell immunotherapy

Adoptive immunotherapy with genetically engineered T cells has the potential to treat cancer and other diseases. The introduction of Strep-tag II sequences into specific sites in synthetic chimeric antigen receptors or natural T-cell receptors of diverse specificities provides engineered T cells with a marker for identification and rapid purification, a method for tailoring spacer length of chimeric receptors for optimal function, and a functional element for selective antibody-coated, microbead-driven, large-scale expansion. These receptor designs facilitate cGMP manufacturing of pure populations of engineered T cells for adoptive T-cell therapies and enable in vivo tracking and retrieval of transferred cells for downstream research applications.

references:

It is great that immunotherapy is being highlighted! However the approach they are using is misguided. Cancer occurs from constant chemical attack by free radicals and other types of chemical or forms of damage like radiation. The objective is prevention and secret is in the diet. If you already have it you have to eliminate all the bad stuff and start consuming nutrients that will enhance your immune system so it takes care of the cancer with the T cells. Watch this video and go to minute 38 where the Doc starts explaining this.https://www.youtube.com/watch?v=Pj1PK0LHJwg

 

Having survived terminal cancer with a dietary approach, what you say is too simplistic.

Cancer is anything that interferes with any of the many growth inhibition pathways the prevent individual cells within the cooperative society of cells that is an animal body from growing in a fashion that puts the whole cooperative system at risk.

Certainly diet, largely via its effect on our immune system, and certainly in some degrees by other mechanisms also, can play a huge role in that. The particular regime I am on is strictly vegan, largely raw, and high dose vitamin c and supplementation of other vitamin/mineral complexes in very low doses.

The work in this article looks very promising, and in most people it would be unnecessary if they changed their diet and bought the contribution from animal products (meat, dairy, fish and foul etc) to below 10% of total calories. Going to zero seems to slightly reduce the risk even further, but not hugely. Along with that one needs to reduce stress (which seems to be not directly about external factors, but more accurately how we contextualise and respond to them).

 

Immunotherapy historically has involved all arms of the immune system in experimental treatments. That includes not only trained white blood cells, but B-cell antibodies and T-cell antibodies. In some experiments they attached poisons such as ricin to kill the cancer cells.Indeed most anti-cancer drugs can theoretically be attached to antibodies to kill of cancer cells specifically.Most approaches have had miraculous cures and remissions of hopelessly ill cancer patients who were dying.They are not offered to people who have no other hope except as small treatment studies.Why? Oncol;ogy is a big medical business, to cure it outright would put Oncologists out of work.The giant pharmaceutical companies that sell super expensive drugs would lose great gobs of money.They have some of the biggest lobbies in congress to maintain their business.
Often Immunotherapy of whatever form will have dangerous side effects.Some people do die from the treatments.It is unetihcal to refuse to give people who have a few weeks or minths to live a shot at these miracle treatments. In the case of enhanced T-cell therapy such as this one it can be difficult to control how extreme the body attacks. Today they have the means to put in genetic switches which will simply turn off the T-cells or any other cell line, by turning off the genes responsible for the action.One such switch is being produced by the company Intrexon using the insect molting hormone ecdysone to stop and start the genes of any organism.There almost certainly could be analogous techniques to biochemically create similar results if we understand how this one works.— I will be dead and gone a thousand years before any of this is cheaply available to the general population.

 

Despite the fact that immunotherapy has attracted considerable interest in recent years because of major progress in the identification of human tumor antigens (TA) suitable for clinical use, considerable obstacles to the development of clinically effective immunotherapy still exists including inability to:

induce expansion of large pools of antigen specific CD8+ T cells

maintain durable anti-tumor immunity > 5 years

overcome inherent tolerogenic mechanisms, such as CD4+CD25+ regulatory T cells (Tregs)

Unfortunately understanding the effectiveness of this new protocol with respect to resolving these obstacles takes time and future studies with larger cohorts.

 

 

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PI3K delta isoform selective inhibitor

Larry H. Bernstein, MD, FCAP, Curator

LPBI

UPDATED 2/22/2020

From: Business Wire source: https://www.businesswire.com/news/home/20190722005555/en/INCB050465-Incyte-Drug-Overview-Product-Profile-2019

INCB050465 (Incyte) Drug Overview & Product Profile 2019: An Oral Phosphoinositide 3-Kinase (PI3K) Delta-Specific Inhibitor –

DUBLIN–(BUSINESS WIRE)–The “INCB050465” report has been added to ResearchAndMarkets.com’s offering.

INCB050465 (Incyte) is an oral phosphoinositide 3-kinase (PI3K) delta-specific inhibitor.

The PI3K pathway has been shown to be highly active in a subset of follicular lymphoma (FL), promoting cell proliferation and survival. INCB050465 inhibits the PI3K-delta isoform with a 20,000-fold selectivity over other PI3K isoforms.

INCB050465 is being developed as a third-line option for FL patients, but the drug will face intense competition from marketed and pipeline PI3K inhibitors because of its late arrival to the market. Upon approval, there will be three other drugs that target the PI3K pathway already approved for FL: Zydelig (idelalisib; Gilead), Aliqopa (copanlisib; Bayer), and Copiktra (duvelisib; Verastem/Infinity/Yakult Honsha Co) are all approved for the third-line setting. Another PI3K inhibitor, umbralisib (TG Therapeutics), is expected to be approved shortly after INCB050465

Analyst Outlook

Umbralisib is being developed for previously treated patients, and will therefore experience use in the second- and third-line settings in combination with TG Therapeutics’ proprietary anti-CD20 drug ublituximab. In addition to entering a crowded drug class, INCB050465’s development appears to be restricted to the US at this time, as clinical development in the pivotal Phase II CITADELNHL trial is limited to that country.

Additional trials in Europe and Japan may be necessary to support approvals in those regions. Clinical development beyond the third-line setting, as well as expanded geographic development, could help INCB050465’s commercial potential, but the drug is likely to gain limited market share compared to its class competitors.

Key Topics Covered:

AMG-319

DRUG APPROVALS BY DR ANTHONY MELVIN CRASTO …..FOR BLOG HOME CLICK HERE

1 Vote

AMG-319

N-((1S)-1-(7-fluoro-2-(2-pyridinyl)-3-quinolinyl)ethyl)-9H-purin-6-amine, WO2008118468

(S)-N-(1-(7-fluoro-2-(pyridin-2-yl)quinolin-3-yl)ethyl)-9H-purin-6-amine

 CAS 1608125-21-8

Chemical Formula: C21H16FN7
Exact Mass: 385.14512

Phosphoinositide-3 kinase delta inhibitor

AMGEN, PHASE 2

PI3K delta isoform selective inhibitor is being investigated in human clinical trials for the treatment of PI3K-mediated conditions or disorders, such as cancers and/or proliferative diseases

Useful for treating PI3K-mediated disorders such as acute myeloid leukemia, myelo-dysplastic syndrome, myelo-proliferative diseases, chronic myeloid leukemia, T-cell acute lymphoblastic leukemia, B-cell acute lymphoblastic leukemia, non-Hodgkins lymphoma, B-cell lymphoma, or breast cancer.

Amgen is developing AMG-319, a small molecule PI3K-δ inhibitor, for treating lymphoid malignancies and solid tumors including, head and neck squamous cell carcinoma.

AMG-319 is a highly selective, potent, and orally bioavailable small molecule inhibitor of the delta isoform of the 110 kDa catalytic subunit of class IA phosphoinositide-3 kinases (PI3K) with potential immunomodulating and antineoplastic activities. PI3K-delta inhibitor AMG 319 prevents the activation of the PI3K signaling pathway through inhibition of the production of the second messenger phosphatidylinositol-3,4,5-trisphosphate (PIP3), thus decreasing proliferation and inducing cell death. Unlike other isoforms of PI3K, PI3K-delta is expressed primarily in hematopoietic lineages. The targeted inhibition of PI3K-delta is designed to preserve PI3K signaling in normal, non-neoplastic cells.

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Angiogenesis Inhibitors [9.5]

Writer and Curator: Larry H Bernstein, MD, FCAP

This article has the following structure:

9.5.1 Motesanib (AMG 706)

9.5.2 Drugs that block cancer blood vessel growth (anti angiogenics)

9.5.3 Recent Advances in Anti-Angiogenic Therapy of Cancer

9.5.4 Angiogenesis inhibitors in cancer therapy: mechanistic perspective on classification and treatment rationales

9.5.5 LUCITANIB a VEGFR/FGFR dual kinase inhibitor in Phase 2 trials

9.5.1 Motesanib (AMG 706)

by DR ANTHONY MELVIN CRASTO Ph.D

http://newdrugapprovals.org/2015/05/15/motesanib-amg-706/

Motesanib (AMG 706) is an experimental drug candidate originally developed by Amgen[1] but is now being investigated by theTakeda Pharmaceutical Company. It is an orally administered small molecule belonging to angiokinase inhibitor class which acts as an antagonist of VEGF receptorsplatelet-derived growth factor receptors, and stem cell factor receptors.[2] It is used as the phosphate salt motesanib diphosphate.

Motesanib, also known as AMG-706, is an orally administered multikinase inhibitor that selectively targets VEGF receptors, platelet-derived growth factor receptors, and Kit receptors.

N-(3,3-Dimethylindolin-6-yl){2-[(4-pyridylmethyl)amino](3-pyridyl)}carboxamide

motesanib-amg-706-a10608

motesanib-amg-706-a10608

http://www.adooq.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/m/o/motesanib-amg-706-a10608.gif

http://www.chemblink.com/products/453562-69-1.htm

9.5.2 Drugs that block cancer blood vessel growth (anti angiogenics)

http://www.cancerresearchuk.org/about-cancer/cancers-in-general/treatment/biological/types/drugs-that-block-cancer-blood-vessel-growth

When it has reached 1 to 2mm across, a tumor needs to grow its own blood vessels in order to continue to get bigger. Some cancer cells make a protein called vascular endothelial growth factor (VEGF). The VEGF protein attaches to receptors on cells that line the walls of blood vessels within the tumour.

Drugs that block blood vessel growth factor

Some drugs block vascular endothelial growth factor (VEGF) from attaching to the receptors on the cells that line the blood vessels. This stops the blood vessels from growing.

A drug that blocks VEGF is bevacizumab (Avastin). It is also a monoclonal antibody.

Drugs that block signalling within the cell

Some drugs stop the VEGF receptors from sending growth signals into the blood vessel cells. These treatments are also called cancer growth blockers or tyrosine kinase inhibitors (TKIs).

Sunitinib (Sutent) is a type of TKI that blocks the growth signals inside blood vessel cells. It is used to treat kidney cancer and a rare type of stomach cancer called gastrointestinal stromal tumour (GIST).

Drugs that affect signals between cells

Some drugs act on the chemicals that cells use to signal to each other to grow. This can block the formation of blood vessels. Drugs that works in this way include thalidomide and lenalidomide (Revlimid).

Each drug has different side effects. You can look up the name of your drug in our cancer drug section to find out about the side effects you may have.

To find trials using anti angiogenesis treatment go to our clinical trials database and type ‘angiogenesis’ into the search box.

http://www.cancer.gov/about-cancer/treatment/types/immunotherapy/angiogenesis-inhibitors-fact-sheet

Tumors can cause their blood supply to form by giving off chemical signals that stimulate angiogenesis. Tumors can also stimulate nearby normal cells to produce angiogenesis signaling molecules. The resulting new blood vessels “feed” growing tumors with oxygen and nutrients, allowing the cancer cells to invade nearby tissue, to move throughout the body, and to form colonies of cancer cells, called metastases. Because tumors cannot grow beyond a certain size or spread without a blood supply, scientists are trying to find ways to block tumor angiogenesis.

Angiogenesis requires the binding of signaling molecules, such as vascular endothelial growth factor (VEGF), to receptors on the surface of normal endothelial cells. When VEGF and other endothelial growth factors bind to their receptors on endothelial cells, signals within these cells are initiated that promote the growth and survival of new blood vessels.

Angiogenesis inhibitors interfere with various steps in this process. For example, bevacizumab (Avastin®) is a monoclonal antibody that specifically recognizes and binds to VEGF (1). When VEGF is attached to bevacizumab, it is unable to activate the VEGF receptor. Other angiogenesis inhibitors, including sorafenib and sunitinib, bind to receptors on the surface of endothelial cells or to other proteins in the downstream signaling pathways, blocking their activities (2).

The U.S. Food and Drug Administration (FDA) has approved bevacizumab to be used alone forglioblastoma that has not improved with other treatments and to be used in combination with other drugs to treat metastatic colorectal cancer, some non-small cell lung cancers, and metastatic renal cell cancer. Bevacizumab was the first angiogenesis inhibitor that was shown to slow tumor growth and, more important, to extend the lives of patients with some cancers.

The FDA has approved other drugs that have antiangiogenic activity, including sorafenib (Nexavar®), sunitinib(Sutent®), pazopanib (Votrient®), and everolimus (Afinitor®). Sorafenib is approved for hepatocellular carcinoma and kidney cancer, sunitinib and everolimus for both kidney cancer and neuroendocrine tumors, and pazopanib for kidney cancer.

Angiogenesis inhibitors are unique cancer-fighting agents because they tend to inhibit the growth of blood vessels rather than tumor cells. In some cancers, angiogenesis inhibitors are most effective when combined with additional therapies, especially chemotherapy. It has been hypothesized that these drugs help normalize the blood vessels that supply the tumor, facilitating the delivery of other anticancer agents, but this possibility is still being investigated.

Angiogenesis inhibitor therapy does not necessarily kill tumors but instead may prevent tumors from growing. Therefore, this type of therapy may need to be administered over a long period.

Initially, it was thought that angiogenesis inhibitors would have mild side effects, but more recent studies have revealed the potential for complications that reflect the importance of angiogenesis in many normal body processes, such as wound healing, heart and kidney function, fetal development, and reproduction. Side effects of treatment with angiogenesis inhibitors can include problems with bleeding, clots in the arteries (with resultant stroke or heart attack), hypertension, and protein in the urine (35). Gastrointestinal perforation and fistulas also appear to be rare side effects of some angiogenesis inhibitors.

In addition to the angiogenesis inhibitors that have already been approved by the FDA, others that target VEGF or other angiogenesis pathways are currently being tested in clinical trials (research studies involving patients). If these angiogenesis inhibitors prove to be both safe and effective in treating human cancer, they may be approved by the FDA and made available for widespread use.

In addition, phase I and II clinical trials are testing the possibility of combining angiogenesis inhibitor therapy with other treatments that target blood vessels, such as tumor-vascular disrupting agents, which damage existing tumor blood vessels (6).

9.5.3 Recent Advances in Anti-Angiogenic Therapy of Cancer

Rajeev S. Samant and Lalita A. Shevde
Oncotarget. 2011 Mar; 2(3): 122–134.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3260813/

More than forty anti-angiogenic drugs are being tested in clinical trials all over the world. This review discusses agents that have approved by the FDA and are currently in use for treating patients either as single-agents or in combination with other chemotherapeutic agents.

Tumor angiogenesis is generation of a network of blood vessels within the cancerous growth. This process can occur two ways: The more accepted model involves the release of signaling molecules by the tumor cells; these molecules activate the surrounding tissue to promote growth of new blood vessels. This stimulates vascular endothelial cells to divide rapidly [910]. The other model proposes the generation of new vasculature by vasculogenic mimicry. This model argues that the tumor cells trans-differentiate in endothelial-like cells and create structures from inside of the tumor tapping into a nearby blood vessel [4].

Escape of the tumor cell from the confines of the primary tumor to distant body parts is the pre-requisite for hematogenous metastasis. This escape route is provided by the tumor vasculature. Thus, it was envisioned that inhibition of angiogenesis will also lead to inhibition of metastasis. This phenomenon was demonstrated by very elegant mouse model studies using angiostatin [1112]. Angiostatin was also demonstrated to be secreted by some primary tumors leading to restricted growth of the metastasis leading to “dormancy” of the metastasis. Mice deficient in angiogenesis (Id1 & Id3 deficient) showed significantly less tumor take rates [13]. Independent studies showed absence of metastasis in angiogenesis deficient mice [1415]. Defective angiogenesis was attributed to impaired VEGF-dependent recruitment of precursor endothelial cells from the bone marrow to the newly developing tumor vasculature [16].

Metastasis of malignant tumors to regional lymph nodes is one of the early signs of cancer spread in patients, and it occurs at least as frequently as hematogenous metastasis [17]. Particularly, in cancers, such as breast cancer, lymphatic metastasis is a predominant route for tumor spread. The contribution of lymphatic system to the tumor growth is an area that is relatively less studied. However, lymphatic vessels are speculated to contribute to tumor growth and metastasis in a variety of ways. The VEGF, FGF2 and PDGF produced by vascular endothelial cells are proposed to be involved in the activation of lymphatic endothelial cells, which in turn produce matrix metalloproteases and urokinase plasminogen activator (uPA) that can promote malignant tumor growth. Thus, there exists a synergistic crosstalk between the tumor and the lymphatic vessels and blood vessels.

Angiogenesis is a complex and intricately regulated process. Like all other regulated biological phenomena, angiogenesis has activators or pro-angiogenic factors and inhibitors or anti-angiogenic factors [9].

The Activators

Tumor cells activate signaling pathways that promote uncontrolled proliferation and survival. These include the PI3K/AKT/mTOR pathway, Hedgehog pathway and, Wnt pathway [1824] that produce pro-angiogenic signaling intermediates [2526]. Among the several reported activators of angiogenesis present in cells two proteins appear to be the most important for sustaining tumor growth: vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). VEGF and bFGF are secreted by the tumor into the surrounding tissue. They bind to their cognate receptors on endothelial cells. This activates a signaling cascade that transmits a nuclear signal prompting target genes to activate endothelial cell growth. Activated endothelial cells also produce matrix metalloproteinases (MMPs). These MMPs break down the extracellular matrix and allow the migration of endothelial cells. The division and migration of the endothelial cells leads to formation of new blood vessels [2728].

The Inhibitors

If angiogenesis is so critical for the tumor growth, then agents that inhibit angiogenesis would have great therapeutic value. With the discovery of endostatin, the concept of anti-angiogenic therapy was launched and popularized by Dr. Folkman [29]. Angiogenesis inhibitors have been discovered from a variety of sources. Some are naturally present in the human body e.g. specific fragments of structural proteins such as collagen or plasminogen (angiostatin, endostatin, tumstatin) [30]. Others are natural products in green tea, soy beans, fungi, mushrooms, tree bark, shark tissues, snake venom etc. [31]. A plethora of synthetic compounds are also characterized to have anti-angiogenic properties [32].

ANTI-ANGIOGENIC TREATMENT OF CANCER

Since angiogenesis is an event critical to primary tumor growth as well as metastasis, anti-angiogenic treatment of tumors is a highly promising therapeutic avenue [33]. Thus, for over last couple of decades, there has been a robust activity aimed towards the discovery of angiogenesis inhibitors [3435]. More than forty anti-angiogenic drugs are being tested in human cancer patients in clinical trials all over the world. From the several anti-angiogenic agents reported, we have focused this review on discussing those agents that have received FDA approval in the United States and are currently in use for treating patients either as a single-agent or in combination with other chemotherapeutic agents (Figure ​(Figure1).1). Based on functionality, the anti-angiogenic drugs can be sub-divided into three main groups:

angiogenesis inhibitors oncotarget-02-122-g001

angiogenesis inhibitors oncotarget-02-122-g001

Figure 1

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3260813/bin/oncotarget-02-122-g001.jpg

Targets of FDA-approved angiogenesis inhibitors: Angiogenesis inhibitors impact both, the tumor as well as the endothelial cells resulting in the disruption of the effects of the microenvironment in promoting tumor growth and angiogenesis

Drugs that inhibit growth of endothelial cells

e.g. Endostatin and combretastatin A4, cause apoptosis of the endothelial cells [36]. Thalidomide is also a potent inhibitor of endothelial cell growth [37].

Drugs that block angiogenesis signaling

e.g. anti-VEGF antibodies (Avastin, FDA approved for colorectal cancer), Interferon-alpha (inhibits the production of bFGF and VEGF) [36].

Drugs that block extracellular matrix breakdown

e.g. inhibitors of MMPs [38].

ANTI-ANGIOGENIC THERAPIES THAT HAVE RECEIVED USA-FDA APPROVAL

Conventional chemotherapy is usually a systemic therapy that tries to capture a narrow therapeutic window offered by rapid proliferation of tumor cells compared to the normal cells. Chemotherapy has significant side effects such as hair loss, diarrhea, mouth ulcer, infection, and low blood counts. Anti-angiogenic therapy has several advantages over chemotherapy as it is mostly not directed towards directly killing cells but stopping the blood vessel formation, an event that is rare in tissues other than growing tumor. Hence it is well tolerated by the patients and has fewer side effects [29]. There are currently seven approved anti-cancer therapies in two primary categories:

  1. Monoclonal antibodies directed against specific pro-angiogenic growth factors and/or their receptors
  2. Small molecule tyrosine kinase inhibitors (TKIs) of multiple pro-angiogenic growth factor receptors.

Besides these, inhibitors of mTOR (mammalian target of rapamycin), proteasome inhibitors and thalidomide have also been reported to indirectly inhibit angiogenesis through mechanisms that are not completely understood.

MONOCLONAL ANTIBODY THERAPIES

Four monoclonal antibody therapies are approved to treat several tumor types:

Bevacizumab (Avastin®)

The first FDA approved angiogenesis inhibitor, Avastin is a humanized monoclonal antibody that binds biologically active forms of vascular endothelial growth factor (VEGF) and prevents its interaction with VEGF receptors (VEGFR-1 and VEGFR-2), thereby inhibiting endothelial cell proliferation and angiogenesis. Bevacizumab has been tested in phase I studies in combination with chemotherapy with a good safety profile [39]. This treatment is approved for metastatic colorectal cancer and non-small cell lung cancer [4043]. Bevacizumab has also evolved as a first line of treatment in combination with paclitaxel in breast cancer patients by virtue of its ability to double median progression-free survival (PFS) [44]. In combination with chemoendocrine therapy (including capecitabine and vinorelbine, and letrozole) bevacizumab treatment significantly decreased the percentage of viable circulating endothelial cells and prevented the chemotherapy-induced mobilization of circulating progenitors [45]. In combination with irinotecan, bevacizumab significantly increased PFS in glioma patients [4647]. VEGF has emerged as a compelling therapeutic target for leukemias. Inhibition of angiogenesis in hematological malignancies interdicts the angiogenesis within the bone marrow ecosystem comprised of multiple cell types, including fibroblasts, endothelial progenitor cells, endothelial cells, dendritic cells and, malignant cells, blocking the availability of nutrients to cancer cells and disrupting crosstalk between the various cell types to curtail the malignant phenotype [48].

Cetuximab (Erbitux®)

This is a monoclonal antibody that binds the extracellular domain of epidermal growth factor receptor (EGFR), preventing ligand binding and activation of the receptor resulting in internalization and degradation of the receptor culminating in inhibition of cell proliferation and angiogenesis. Cetuximab downregulated VEGF expression in a dose-dependent manner in a human colorectal carcinoma (CRC) cell line and in human CRC mouse xenografts [49]. The xenografts also showed a significant reduction in blood vessel counts following several rounds of cetuximab treatment [49], indicating that the tumor-promoting effects of EGFR overexpression may be mediated through VEGF stimulation and tumor angiogenesis. This treatment is approved for metastatic CRC and head and neck cancer [50] in patients who are refractory to irinotecan-based chemotherapy. In combination with irinotecan (an inhibitor of topoisomerase I), cetuximab is the first monoclonal antibody that has been approved by the FDA as second-line treatment for metastatic colorectal cancer [5152]. In Phase I and Phase III trials [5354] cetuximab significantly improved the effects of radiotherapy in patients with unresectable (cannot be removed by surgery) squamous cell carcinoma of the head and neck (SCCHN). Cetuximab has also been shown to sensitize cells to radiation and chemotherapy, potentially through blocking EGFR nuclear import and the associated activation of DNA protein kinase enzymes necessary for repairing radiation- and chemotherapy-induced DNA damage [55]. Compared to radiation alone, cetuximab plus radiation therapy can nearly double the median survival in patients with a certain kind of head and neck cancer that has not spread to other parts of the body [54] making cetuximab the only drug achieving interesting response rate in second line treatment of advanced SCCHN [56]. Cetuximab was also found to be tolerated well in combination with cisplatin, or carboplatin, and fluorouracil [5758].

Panitumumab (Vectibix™)

It is a fully humanized anti-EGFR monoclonal antibody that binds specifically to the human EGFR. Panitumumab is a recombinant human monoclonal antibody [59]; therefore, the risk of an infusion reaction is minimized. Vectibix® is indicated as a single agent for the treatment of EGFR-expressing, metastatic colorectal carcinoma with disease progression on or following fluoropyrimidine-, oxaliplatin-, and irinotecan-containing chemotherapy regimens [6062]. The effectiveness of Vectibix® as a single agent for the treatment of EGFR-expressing, metastatic CRC is based on progression-free survival [6364]. Panitumumab is used in patients who are not responding to regimens containing fluorouracil, oxaliplatin, and irinotecan [60]. Patients often receive panitumumab after receiving bevacizumab or cetuximab. Panitumumab can be given with FOLFOX (oxaliplatin, leucovorin, and fluorouracil) or FOLFIRI (irinotecan, leucovorin, and fluorouracil) regimens, or as a single agent. Currently no data are available that demonstrate an improvement in disease-related symptoms or increased survival with Vectibix® in colon cancer [65]. This drug is also being tested for aerodigestive track and head and neck cancer [6667].

Trastuzumab (Herceptin®)

Is a humanized monoclonal antibody that binds the extracellular domain of HER-2, which is overexpressed in 25-30% of invasive breast cancer tumors [68]. HER2-positive breast cancer is highly aggressive disease with high recurrence rate, poorer prognosis with decreased survival compared with HER2-negative breast cancer [69]. Herceptin® is designed to target and block the function of HER2 protein overexpression. This is the first humanized antibody is approved for Breast cancer [70]. Herceptin® is approved by the FDA to treat HER2 positive breast cancer that has metastasized after treatment with other anticancer drugs [71]. It is also approved to be used with other drugs to treat HER2-positive breast cancer that has spread to the lymph nodes to be used after surgery. The FDA first approved Herceptin in September 1998 [7173]. In November 2006, the FDA approved Herceptin as part of a treatment regimen containing doxorubicin, cyclophosphamide and paclitaxel, for the adjuvant treatment of patients with HER2-positive, node-positive breast cancer (http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/default.htm). In January 2008, the FDA approved Herceptin as a single agent for the adjuvant treatment of HER2-overexpressing node-negative (ER/PR-negative or with one high-risk feature) or node-positive breast cancer, following multi-modality anthracycline-based therapy (http://biopharminternational.findpharma.com/biopharm/News/FDA-Approves-Expanded-Adjuvant-Indications-for-Her/ArticleStandard/Article/detail/518867). Trastuzumab is also being studied in the treatment of other types of cancers such as pancreatic [74], endometrial [75], lung [76], cervical [77] and ovarian cancer [78]

SMALL MOLECULE TYROSINE KINASE INHIBITORS (TKIs)

Protein tyrosine kinases have emerged as crucial targets for therapeutic intervention in cancer especially because they play an important role in the modulation of growth factor signaling. As per ClinicalTrials.gov (www.clinicaltrials.gov), there are 43 ongoing studies on tyrosine kinase inhibitors in angiogenesis. Since discussing all of them is beyond the scope of this article, we have focused our discussion on the three TKIs that are currently approved as anti-cancer therapies:

Erlotinib (Tarceva®)

Erlotinib hydrochloride (originally coded as OSI-774) is an orally available, potent, reversible, and selective inhibitor of the EGFR (ErbB1) tyrosine kinase activity. Erlotinib hydrochloride has been approved by FDA for treatment of patients with locally advanced or metastatic NSCLC after failure of at least one prior chemotherapy regimen [7980]. Interesting recent studies have demonstrated that since Erlotinib and Bevacizumab act on two different pathways critical to tumor growth and dissemination, administering these drugs concomitantly may confer additional clinical benefits to cancer patients with advanced disease. This combination therapy may prove to be a viable second-line alternative to chemotherapy in patients with NSCLC [81]. Also, for patients with locally advanced, unresectable or metastatic pancreatic carcinoma, Erlotinib has received FDA approval for the treatment in combination with gemcitabine [8283]. Erlotinib is also being studied in the treatment of other types of cancers. For example combination of Erlotinib with Bevacizumab has been evaluated in metastatic breast cancer [84], hepatocellular carcinoma [85] and in metastatic renal cancer [86] as phase II trials. Outcomes for prostate, cervical and colorectal cancers treated with Erlotinib are cautiously optimistic [8789].

Sorafenib (Nexavar®)

Sorafenib is an orally active inhibitor of VEGFR-1, VEGFR-2, VEGFR-3, PDGFR-β, and Raf-1 tyrosine kinase activity [90]. It has received the approval of FDA for the treatment of patients with unresectable hepatocellular carcinoma [91] and advanced renal cell carcinoma [92]. However, not all advanced hepatocellular carcinoma patients were able to tolerate sorafenib and some patients experienced tumor progression [91]. Sorafenib has shown improvements in PFS in patients with renal cell carcinoma [93]. It is one of the aggressively studied drugs. According to the NCI clinical trials search results, there are about 168 active clinical trials involving sorafenib in a variety of cancers.

Sunitinib (Sutent®)

Sunitinib targets activity of multiple tyrosine kinases such as VEGFR-1, VEGFR-2, VEGFR-3, PDGFR- β, and RET [94]. It is approved by FDA as Sunitinib malate for treating advanced (metastatic) renal cell carcinoma [95]. It is also approved by FDA for gastrointestinal stromal tumor (GIST) in patients whose disease has progressed or who are unable to tolerate treatment with imatinib (Gleevec), the current treatment for GIST patients [9596]. Sunitinib has shown early evidence of anti-tumor activity in Phase II trials in US, European and Asian patients with locally advanced, unresectable and metastatic hepatocellular carcinoma. A Phase III trial of sunitinib in hepatocellular carcinoma is ongoing [97]. According to the NCI clinical trials search results, Sunitinib is currently evaluated in about 150 active clinical trials. It is evaluated for ovarian [98], breast [99] and non small cell lung cancer [100] among others [101].

Inhibitors of mTOR

mTOR plays a part in the PI3 kinase/AKT pathway involved in tumor cell proliferation and angiogenesis [102]. Rapamycin and related mTOR inhibitors inhibit endothelial cell VEGF expression, as well as VEGF-induced endothelial cell proliferation [103]. Inhibitors of mTOR are an important class of anti-angiogenic agents. These include: deforolimus, everolimus, rapamycin (sirolimus), and temsirolimus [104105]. Temsirolimus (Toricel™) is a small molecule inhibitor of mTOR, approved for treating advanced renal cell carcinoma [106]. It is a type of rapamycin analog and a type of serine/threonine kinase inhibitor, it is also called CCI-779. In pre-clinical models combination therapy for treating breast cancer using anti-estrogen, ERA-923, and temsirolimus has been successfully tested [107]. It is found to be highly effective against human melanoma when tested in combination with cisplatin and DTIC (in independent studies) in a SCID mouse xenotranplantation model [108109]. There are over 41 active studies of Temsirolimus for a variety of solid tumors [110]. mTOR inhibition has also been strongly advocated in as a putative cancer therapeutic strategy for urologic malignancies [111]. In a pilot study (6 patients) with imatinib-resistant CML, rapamycin induced major and minor leukocyte responses, with an observed decrease in the mRNA levels of VEGFA in circulating leukaemic cells [112]. Combination treatments for breast cancer with aromatase inhibitor [113] and letrozol [114] are also being evaluated. Rapamycin treatment brought partial responses (>50% reduction in the absolute number of blood blasts) and stable disease in adult refractory/relapsed AML [115]. In a recent report, Deforolimus was studied in a Phase 2 trial in pretreated patients with various hematological malignancies, including ALL, AML, CLL, CML, MDS, agnogenic myeloid metaplasia, mantle cell lymphoma and T-cell leukemia/lymphoma [116]. Overall, 40% of deforolimus-treated patients experienced hematological improvement or stable disease.

OTHER ANGIOGENIC AGENTS

Bortezomib (Velcade®)

Is a proteasome inhibitor that disrupts signaling of cancer cells, leading to cell death and tumor regression. It is the first compound in its class to be used in clinical practice. It has indirect anti-angiogenic properties [117]. While its exact mechanism is not understood, it induces the pro-apoptotic BH3-only family member NOXA in a p53 independent fashion triggering of a caspase cascade culminating in apoptosis in melanoma and myeloma cells [118]. It is FDA-approved for the treatment of myeloma that has relapsed after two prior treatments (or where resistance has developed following the last treatment). It was also found to induce high quality responses as third line salvage therapy with acceptable toxicity in a significant proportion of homogeneously pre-treated myeloma patients with progressive disease after autologous transplantation and thalidomide. [119]. In a Phase 3 trial involving 669 myeloma patients treated with at least one prior therapy, bortezomib increased median, improved overall survival, and increased response rate, compared with high-dose dexamethasone [120]. In combination with doxorubicin and gemcitabine, bortezomib was also found to be effective in heavily pretreated, advanced Cutaneous T cell Lymphomas (CTCL) [121]. Bortezomib was also reported to be active as a single agent for patients with relapsed/refractory CTCL and Peripheral T Cell Lymphoma (PTCL) with skin involvement [122]. On the contrary, the use of bortezomib was discouraged after a phase II study revealed that found in combination with dexamethasone, bortezomib is not active in heavily pre-treated patients with relapsed Hodgkin’s lymphoma [123124].

Thalidomide (Thalomid®)

Possesses immunomodulatory, anti-inflammatory, and anti-angiogenic properties, although the precise mechanisms of action are not fully understood. Thalidomide was the first angiogenesis inhibitor to demonstrate clinical efficacy in multiple myeloma [37125]. Specifically in myeloma, thalidomide down-regulated VEGF secretion from bone marrow endothelial cells obtained from patients with active disease. In a landmark Phase 2 clinical trial, 169 previously treated patients with refractory myeloma received thalidomide monotherapy [126]. Partial response, was achieved in 30% of patients, and 14% achieved a complete or nearly complete remission. The survival rate at 2 years was 48%. These results led to many subsequent clinical studies of thalidomide in myeloma, leading ultimately to FDA approval of the drug in 2006, for the treatment of newly diagnosed multiple myeloma, in combination with dexamethasone. In the pivotal Phase 3 trial, the response rate in patients receiving thalidomide plus dexamethasone was 63% compared to 41% with dexamethasone alone [127]. Long-term outcome measures, including time-to-progression (TTP) and PFS, were recently reported for a 470 patient randomized, placebo-controlled Phase 3 clinical trial of a similar protocol in newly diagnosed multiple myeloma, with comparable overall response rates [128]. Significant increases resulted in both median TTP and median PFS for the thalidomide plus dexamethasone group versus dexamethasone alone.

Thalidomide was found to be moderately tolerated and minimally effective in patients with histologically proven advanced hepatocellular carcinoma [129]. Thalidomide provided no survival benefit for patients with multiple, large, or midbrain metastases when combined with WBRT (whole-brain radiation therapy) [130]. On the contrary, thalidomide did not significantly add to the efficacy of the fludarabine, carboplatin, and topotecan (FCT) regimen in poor prognosis AML patients [131] and was also ineffective in improving prognosis or decreasing plasma VEGF levels in patients with persistent or recurrent leiomyosarcoma of the uterus [132].

METRONOMIC THERAPY

While conventional anti-angiogenic therapy is based on Maximum Tolerated Doses (MTD), the cells involved in angiogenesis may regenerate during the three- to four-week interval between cycles of the chemotherapy. Taking advantage of the fact that endothelial cells are about 10–100 times more susceptible to chemotherapeutic agents than cancer cells, therapy based on daily, oral, low-dose chemotherapeutic drugs was designed. Metronomic chemotherapy refers to the close, rhythmic administration of low doses of cytotoxic drugs, with minimal or no drug-free breaks, over prolonged periods. Metronomic therapy appears promising mainly due to the fact that its anti-angiogenic and anti-tumorigenic effects are accompanied by low toxicity, limited side effects, no need for hospitalization and allowing for feasible combinations with selective inhibitors of angiogenesis. There are several foreseeable advantages and opportunities for metronomic chemotherapy: activity against the parenchymal and stromal components, pro-apoptotic activity, reduction of the likelihood of emergence of acquired resistance, feasibility of long term administration and acceptable systemic side effects [133]. In a pilot phase II study conducted by Correale et al [134] to investigate the toxicity and activity of the novel metronomic regimen of weekly cisplatin and oral etoposide in high-risk patients with NSCLC, the objective response rate was 45.2%, disease control was 58.1%, meantime to progression and survival were 9 and 13 months, respectively. Pharmacokinetic analysis showed that this regimen allowed a greater median monthly area under the curve of the drugs than conventional schedules. In a Phase I trial of metronomic dosing of docetaxel and thalidomide, of the 26 patients with advanced tumors enrolled, prolonged freedom from disease progression was observed in 44.4% of the evaluable patients [135].

Circulating endothelial progenitor cells (EPCs) also participate in tumor angiogenesis. In a study comparing the effects of metronomic chemotherapy over conventional dose-dense chemotherapy, it was found that the numbers of circulating EPCs and the plasma levels of VEGF increased sharply, doubling pre-therapeutic levels at day 21 after conventional chemotherapy, whereas under low-dose metronomic chemotherapy, the numbers of circulating EPCs decreased significantly and VEGF plasma concentrations remained unchanged. These observations provide evidence that conventional dose-dense chemotherapy leads to rebound EPC mobilization even when given with adjuvant intention, while low-dose metronomic scheduling of cytotoxic substances such as trofosfamide may sharply reduce EPC release into the circulation. [136].

Combined bevacizumab and metronomic oral cyclophosphamide was also discovered to be a safe and effective regimen for heavily pre-treated ovarian cancer patients [137]. Treatment with metronomic capecitabine and cyclophosphamide in combination with bevacizumab was shown to be effective in advanced breast cancer and additionally was minimally toxic [138]. Metronomic treatment with carboplatin and vincristine associated with fluvastatin and thalidomide significantly increased survival of pediatric brain stem tumor patients. Tumor volume showed a significant reduction accompanied by increased quality of life [139]. Thus, given the fact that the most evident effect of selective anti-angiogenic agents (i.e. bevacizumab) is the significant prolonging of the duration of response obtainable by chemotherapy alone, with minimal possible side effects of cytotoxic agents given in association metronomic chemotherapy should be considered both as novel up-front or maintenance treatment in patients with biologically poorly aggressive advanced cancer diseases [140].

Overall, metronomic chemotherapy was able to induce tumor stabilization and prolong the duration of clinical benefit, without much associated toxicity. Emerging evidence suggests that metronomic chemotherapy could also activate the host immune system and potentially induce tumor dormancy [141143].

CONCLUSIONS AND FUTURE PERSPECTIVES

While angiogenesis as a hallmark of tumor development and metastasis is now a validated target for cancer treatment, the overall benefits of anti-angiogenic drugs from the perspective of impacting survival have left much to desire, endorsing a need for developing more effective therapeutic regimens e.g., combining anti-angiogenic drugs with established chemotherapeutic drugs [144145]. There are now several agents that target the tumor vasculature through different pathways, either by inhibiting formation of the tumor neovasculature or by directly targeting the mature tumor vessels. The main body of evolving evidence suggests that their effects are compounded by their synergistic use with conventional chemotherapy rather than individual agents. Anti-angiogenic drugs such as bevacizumab can bring about a transient functional normalization of the tumor vasculature. This can have an additive effect when co-administered with chemo/radiotherapy. But long term inhibition of angiogenesis reduces tumor uptake of co-administered chemotherapeutic agents. This underscores the need for discovering new targets for anti-angiogenic therapy in order to effectively prohibit angiogenesis and circumvent mechanisms that contribute to resistance mechanisms that emerge with long term use of anti-angiogenic therapies. It also warrants a need to define reliable surrogate indicators of effectiveness of the anti-angiogenic therapy as well as dependable markers for identifying the patients who are most likely to benefit from the combination of anti-angiogenic therapy and conventional chemotherapy.

Several new frontiers are emerging. New advances in understanding endothelial cells, which constitute the tumor vasculature, towards developing antiangiogenic strategies are one of the important ones [146147]. Novel cellular targets such as integrins and microRNAs and novel treatment options such as possible use of pharmaconutrients to modulate angiogenic pathways need careful testing and evaluation [148151]. Finally, the administration of these drugs in a metronomic schedule is likely to improve the overall response to anti-angiogenic drugs making it feasible to administer them with conventionally toxic chemotherapeutic drugs, thus increasing the armamentarium of drug combinations that can be employed for treatment.

9.5.4 Angiogenesis inhibitors in cancer therapy: mechanistic perspective on classification and treatment rationales

El-Kenawi AE1, El-Remessy AB.
Br J Pharmacol. 2013 Oct; 170(4):712-29.
http://dx.doi.org:/10.1111/bph.12344

Angiogenesis, a process of new blood vessel formation, is a prerequisite for tumor growth to supply the proliferating tumor with oxygen and nutrients. The angiogenic process may contribute to tumour progression, invasion and metastasis, and is generally accepted as an indicator of tumor prognosis. Therefore, targeting tumor angiogenesis has become of high clinical relevance. The current review aimed to highlight mechanistic details of anti-angiogenic therapies and how they relate to classification and treatment rationales. Angiogenesis inhibitors are classified into either direct inhibitors that target endothelial cells in the growing vasculature or indirect inhibitors that prevent the expression or block the activity of angiogenesis inducers. The latter class extends to include targeted therapy against oncogenes, conventional chemotherapeutic agents and drugs targeting other cells of the tumor micro-environment. Angiogenesis inhibitors may be used as either monotherapy or in combination with other anticancer drugs. In this context, many preclinical and clinical studies revealed higher therapeutic effectiveness of the combined treatments compared with individual treatments. The proper understanding of synergistic treatment modalities of angiogenesis inhibitors as well as their wide range of cellular targets could provide effective tools for future therapies of many types of cancer.

Two major processes of blood vessel formation are implicated in the development of vascular system: vasculogenesis and angiogenesis. Vasculogenesis prevails in the embryo and refers to the formation ofde novo blood vessels by in situ differentiation of the mesoderm-derived angioblasts and endothelial precursors. Angiogenesis is the formation of new capillaries from pre-existing vessels and circulating endothelial precursors (Polverini, 2002; Chung et al., 2010; Ribatti and Djonov, 2012). Angiogenesis is a tightly controlled dynamic process that can occur physiologically in those tissues that undergo active remodeling in response to stress and hypoxia (Carmeliet, 2003; Folkman, 2007). However, it can be aberrantly activated during many pathological conditions such as cancer, diabetic retinopathy as well as numerous ischemic, inflammatory, infectious and immune disorders (Carmeliet, 2003; Ali and El-Remessy, 2009; Willis et al., 2011). Although the concept of proposing angiogenesis inhibitors as anticancer drugs received considerable skepticism when first presented by Dr. Folkman in the early 1970s (Folkman, 1971), active research in the field and subsequent clinical trials eventually resulted in US Food and Drug Administration (FDA) approval of bevacizumab for colorectal cancer in 2004 (Cohen et al., 2007). Since then, several angiogenic inhibitors have been identified. This review will provide an overview of the key mechanisms involved in tumor angiogenesis, classification of angiogenesis inhibitors as well as treatment rationales from the mechanistic point of view.

Sustained angiogenesis as a hallmark of cancer

Proliferating tumours tend to activate an angiogenic phenotype to fulfil their increased demand of oxygen and nutrients (Hanahan and Folkman, 1996; Carmeliet, 2005). Additionally, paracrine release of anti-apoptotic factors from activated endothelial cells in the newly formed vasculature supplies tumour cells with a survival privilege (Folkman, 2003). Consequently, in order to progress, tumors tend to activate an event called ‘angiogenic switch’ by shifting the balance of endogenous angiogenesis inducers and inhibitors towards a pro-angiogenic outcome. As a result, dormant lesion progresses into outgrowing vascularized tumor and eventually into a malignant phenotype (Hanahan and Folkman, 1996; Baeriswyl and Christofori, 2009). Hypoxia drives such imbalance through up-regulation of the transcription factor hypoxia inducible factor-1α (HIF-1α), which in turn increases the expression of many angiogenesis inducers as well as suppresses the expression of endogenous angiogenesis inhibitors (Pugh and Ratcliffe, 2003). In spite of that, accumulating evidence indicates that angiogenic cascade can be also driven by alternative HIF-1-independent pathways (Mizukami et al., 2007; Arany et al., 2008; Lee, 2013).

As summarized in Table 1, the angiogenesis inducers are a wide range of mediators that include many growth factors, a plethora of cytokines, bioactive lipids, matrix-degrading enzymes and a number of small molecules (Folkman, 1995; Folkman, 2003; Lopez-Lopez et al., 2004; Bouis et al., 2006; El-Remessy et al., 2007; Bid et al., 2011; MacLauchlan et al., 2011; Murakami, 2011; Fagiani and Christofori, 2013; Qin et al., 2013). Pro-angiogenic growth factors mostly activate a series of surface receptors in a series of paracrine and autocrine loops with the VEGF-A signaling representing the critical rate-limiting step, physiologically and pathologically. VEGF-A (traditionally known as VEGF) is the most potent VEGF isoform that acts mainly on VEGF receptor 2 (VEGFR2) to mediate vascular permeability, endothelial proliferation, migration and survival (Takahashi and Shibuya, 2005; Bouis et al., 2006). In spite of the well-established master roles of VEGF signaling in literature, those processes are probably accomplished through a highly regulated interplay between VEGF and other pro-angiogenic factors. In this context, basic fibroblast growth factor (bFGF) activation of the endothelium is required for maintenance of VEGFR2 expression and the ability to respond to VEGF stimulation (Murakami et al., 2011). Similarly, sphingosine-1-phosphate (S1P), a pleiotropic bioactive lipid that can directly contribute to tumor angiogenesis (reviewed in Sabbadini, 2011), is needed for VEGF-induced blood vessel formation, indicating the cooperation between S1P and VEGF in tumor angiogenesis (Visentin et al., 2006). As a net result, the pro-angiogenic interplay of those ligands and others dominates over the activities of two dozen endogenous angiogenesis inhibitors that can be either matrix-derived inhibitors or non–matrix-derived inhibitors (Nyberg et al., 2005).

Table 1. Pro-angiogenic mediators implicated in tumor angiogenesis

Category Examples References
Growth factors VEGFs Bouis et al., 2006
FGFs Ibid
TGFs Ibid
PDGFs Ibid
Insulin-like growth factors Lopez-Lopez et al., 2004; Bid et al., 2011
ANGs Fagiani and Christofori, 2013
Cytokines IL-8 Strieter et al., 2004
CSF-1 Lin et al., 2006
Bioactive lipids PGE2 Wang and Dubois, 2010
S1P Murakami, 2011
Matrix-degrading enzymes MMPs Bourboulia and Stetler-Stevenson, 2010
Heparanases Vlodavsky and Friedmann, 2001
Small mediators NO MacLauchlan et al., 2011
Peroxynitrite El-Remessy et al., 2007
Serotonin Qin et al., 2013
Histamine Qin et al., 2013

The multistep angiogenic process starts with vasodilation and increased permeability of existing vessels in response to tumor cell-secreted VEGF. This is accompanied by loosening of pericytes covering mediated by angiopoietin-2 (ANG2), a ligand of tyrosine kinase with immunoglobulin-like and EGF-like domains 2 (TIE2) receptor (Bergers and Benjamin, 2003; Jain, 2003; Fagiani and Christofori, 2013). Meanwhile, many secreted matrix-degrading enzymes, such as MMPs and heparanases, function in concert to dissolve the basement membrane and to remodel the extracellular matrix (ECM) as well as to liberate more pro-angiogenic growth factors (bFGF and VEGF) from matrix heparan sulfate proteoglycans (HSPGs) respectively (Houck et al., 1992; Whitelock et al., 1996; Vlodavsky and Friedmann, 2001; Tang et al., 2005; van Hinsbergh and Koolwijk, 2008). The overall chemotactic angiogenic stimuli guide endothelial cells to migrate, to align into tube-like structures and to eventually form new blood vessels. However, such blood vessels are characterized by being disorganized, chaotic, hemorrhagic and poorly functioning (Bergers and Benjamin, 2003).

The angiogenic phenotype in tumor micro-environment can further be sustained and extravagated by the recruitment of other types of stromal cells. Stromal cells such as fibroblasts, mesenchymal stem cells and various bone marrow-derived myeloid cells including macrophages, TIE2-expressing monocytes, neutrophils and mast cells contribute to tumor angiogenesis through their production of growth factors, cytokines and proteases (Murdoch et al., 2008; Joyce and Pollard, 2009; Cirri and Chiarugi, 2011). For example, in response to cancer cell-derived TGF-β, PDGF or bFGF, fibroblasts are transformed to an activated phenotype with a higher proliferative activity and myofibroblastic characteristics (Kalluri and Zeisberg, 2006; Cirri and Chiarugi, 2011). Such carcinoma-associated fibroblasts (CAFs) were shown to promote angiogenesis and metastasis by secreting large amounts of MMP-2 and MMP-9 as well as by expressing many cytokines and chemokines that resulted in immune cell infiltration (Gerber et al., 2009; Giannoni et al., 2010). Furthermore, it has been shown that PDGF-C produced by CAFs is able to elicit VEGF production from tumor cells, thereby sustaining the angiogenic shift (Crawford et al., 2009). Similarly, tumor-associated macrophages (TAMs), one of the bone marrow myeloid-derived cells, are induced to develop into polarized type II (alternatively activated or M2 macrophages), upon exposure to tumor hypoxia and tumor cell-derived cytokines (Leek et al., 2002; Rogers and Holen, 2011). M2 macrophages tend to produce many pro-angiogenic growth factors, cytokines and matrix-degrading enzymes such as VEGF, PDGF, bFGF, TNF-α, COX-2, MMP-9, MMP-7 and MMP-12 (Lewis and Pollard, 2006).

From another perspective, angiogenesis may be dispensable for progression of some malignancies. For example, some tumours may co-opt pre-existent vessels as an alternative way to obtain blood supply. Vessel co-option was first described in the brain, one of the most densely vascularized organs, in which tumours may develop in earlier stages without the activation of angiogenic response (Holashet al., 1999; Leenders et al., 2002; Bergers and Benjamin, 2003; Hillen and Griffioen, 2007). In another example, hypovascularized tumors such as pancreatic ductal adenocarcinoma may involve certain adaptation to flourish in the absence of prominent angiogenesis (Bergers and Hanahan, 2008). Obviously, in both cases, tumors may be intrinsically indifferent to angiogenesis inhibitors. However, in most other cases, therapy directed towards the vasculature of solid tumors is being considered as an important direction in cancer treatment.

Classification of angiogenesis inhibitors

Growth of newly formed vessels in tumor micro-environment can be inhibited directly by targeting endothelial cells in the growing vasculature or indirectly by targeting either tumor cells or the other tumor-associated stromal cells. Therefore, angiogenesis inhibitors can be classified into direct and indirect inhibitors (Kerbel and Folkman, 2002; Folkman, 2007).

Direct endogenous inhibitors of angiogenesis

Direct endogenous inhibitors of angiogenesis, such as angiostatin, endostatin, arrestin, canstatin, tumstatin and others, are fragments released on proteolysis of distinct ECM molecules. Endogenous inhibitors prevent vascular endothelial cells from proliferating, migrating in response to a spectrum of angiogenesis inducers, including VEGF, bFGF, IL-8 and PDGF (Kerbel and Folkman, 2002; Abdollahi et al., 2004; Mundel and Kalluri, 2007; Ribatti, 2009). This direct anti-angiogenic effect may be mediated by interference with endothelial integrins along with several intracellular signaling pathways (Mundel and Kalluri, 2007). For example, the ability of tumstatin-derived active peptide to inhibit angiogenesis and tumour growth is associated with the expression of the adhesion receptor, αvβ3 integrin, on tumor endothelial cells (Eikesdal et al., 2008). Through binding αvβ3 integrin, full tumstatin was found to inhibit endothelial cell activation of focal adhesion kinase, PI3K, Akt, mammalian target of rapamycin (mTOR) and others (Maeshima et al., 2002). Direct targeting of those signaling pathways by endogenous inhibitors was thought to be the least likely to induce acquired drug resistance because they target endothelial cells with assumed genetic stability rather than unstable mutating tumour cells (Kerbel and Folkman, 2002). However, endostatin has not yet led to any documented benefit to patients in randomized phase III trials, or even modest activity in phase II trials (Ellis and Hicklin, 2008).

Indirect inhibitors of angiogenesis

Indirect inhibitors of angiogenesis classically prevent the expression or block the activity of pro-angiogenic proteins (Folkman, 2007). For example, Iressa, an EGF receptor (EGFR) TK inhibitor (TKI), blocks tumour expression of many pro-angiogenic factors; bevacizumab, a monoclonal antibody, neutralizes VEGF after its secretion from tumour cells whereas sunitinib, a multiple receptor TKI, blocks the endothelial cell receptors (VEGFR1, VEGFR2 and VEGFR3), preventing their response to the secreted VEGF (Folkman, 2007; Roskoski, 2007). In addition, this class extends to include conventional chemotherapeutic agents, targeted therapy against oncogenes and drugs targeting other cells of the tumor micro-environment (Kerbel et al., 2000; Ferrara and Kerbel, 2005).

Conventional chemotherapeutic agents

Conventional chemotherapeutic agents have been shown to have anti-angiogenic properties in addition to the ability to induce direct cancer cell death. Such chemotherapeutic agents can affect the endothelial cell population in the tumour bed during treatment cycles because they have significantly higher proliferation rates than resting endothelium outside a tumor, making them more susceptible to cytotoxic effect (Kerbel et al., 2000; Folkman, 2003). However, the cyclic treatment rationale of cytotoxic drugs allows the potential damage to the tumour vasculature to be repaired during the long breaks. Thus, continuous low doses of chemotherapeutic agents were suggested as a way to reduce side effects and drug resistance (Drevs et al., 2004). This modality is termed metronomic therapy, and clinically, it refers to the daily administration of 5–10% of the phase II-recommended dose of the chemotherapeutic agent (Penel et al., 2012). The extended use of such low doses of cytotoxic agents elicits an anti-angiogenic activity through induction of endothelial cell apoptosis and decreasing the level of circulating endothelial precursors (Hamano et al., 2004; Shahrzad et al., 2008). In clinical investigations, metronomic dosing of cyclophosphamide and others showed promising efficacy in patients with advanced, multiple metastasized and/or multiple pretreated solid tumours (Lord et al., 2007; Fontana et al., 2010; Nelius et al., 2011; Gebbia et al., 2012; Briasoulis et al., 2013; Navid et al., 2013).

VEGF-targeted therapy

VEGF-targeted therapy includes neutralizing antibodies to VEGF (e.g. bevacizumab) or VEGFRs (e.g. ramucirumab), soluble VEGFR/VEGFR hybrids (e.g. VEGF-Trap) and TKIs with selectivity for VEGFRs (e.g. sunitinib and sorafenib; Baka et al., 2006; Ellis and Hicklin, 2008; Hsu and Wakelee, 2009). Bevacizumab, a humanized monoclonal antibody against all isoforms of VEGF-A, has been approved for the treatment of colorectal, lung, glioblastoma and renal cell carcinoma (Hsu and Wakelee, 2009). Many other clinical trials with promising efficacy were also conducted in other cancers such as head and neck cancer, hepatocellular carcinoma, ovarian cancer, metastatic melanoma and gastric cancer (Argiris et al., 2011; 2013; Burger et al., 2011; Ohtsu et al., 2011; Fang et al., 2012; Minor, 2012; Schuster et al., 2012; Van Cutsem et al., 2012). However, for metastatic breast cancer, bevacizumab had been initially granted an accelerated FDA approval, which was later withdrawn due to lack of improvement evidence in disease-related symptoms or overall survival (Burstein, 2011; Montero et al., 2012). Similarly, clinical trials showed that the addition of bevacizumab to the treatment regimens of advanced pancreatic cancer did not extend overall survival (Chiu and Yau, 2012). The neutralization of VEGF-A can also be achieved by soluble receptor construct (VEGF-Trap) that monomerically ‘traps’ the different isoforms of VEGF-A, in addition to VEGF-B and placental growth factor (Rudge et al., 2007). VEGF-Trap showed clinical benefit in a phase III trial of oxaliplatin pretreated metastatic patients with colorectal cancer, and is currently being investigated in a prostate cancer phase III trial (Gaya and Tse, 2012). TKIs are small molecules with different chemical structures that have the ability to interact physically with the highly conserved kinase domain shared by different VEGFRs as well as PDGF receptors (PDGFRs), FGF receptors (FGFRs), EGFR, Raf kinases and c-Kit (a receptor of the pluripotent cell growth factor, stem cell factor). Such interaction directly inhibits tyrosine phosphorylation and the subsequent many downstream pro-angiogenic signaling networks (Baka et al., 2006; Ivy et al., 2009). Those multi-targeted TKIs demonstrated efficacy against various solid malignancies in different clinical trials, some of which have lead eventually to FDA approval of sunitinib and sorafenib. Sunitinib, known to inhibit several receptor TKs (RTKs) including VEGFR1–3, PDGFR-α, PDGFR-β, c-Kit, colony-stimulating factor-1 receptor (CSF-1R) and Flt-3, was approved for the treatment of renal cell carcinoma and gastrointestinal stromal cell tumours. Sorafenib that acts also by inhibiting VEGFR1–3 and PDGFR-β in addition to the serine–threonine kinases Raf-1, B-Raf, was approved for hepatocellular carcinoma in addition to renal cell carcinoma (Llovet et al., 2008; Ivy et al., 2009; Huang et al., 2010).

FGF-targeted therapies

FGF-targeted therapies were recently reconsidered as promising anti-angiogenic and anti-tumor agents after a long period of little attention for drug development, partly due to redundancy (Bono et al., 2013). The FGFR superfamily with its 18 ligands and four receptors has been involved in endothelial cell migration, proliferation and differentiation (Presta et al., 2005). Therapeutic targeting of FGF/FGFR signalling was accomplished by either monoclonal antibodies that inhibit FGFs binding, small molecules that inhibit FGFR TK activity or allosteric modulators that bind the extracellular FGFR domain. Monoclonal antibodies against bFGF displayed potent anti-tumor and anti-angiogenic effects in different preclinical cancer models, which warrant further clinical evaluation (Zhao et al., 2010; Wang et al., 2012). Pan inhibitors of the FGFR TKs such as AZD4547 (blocks the activity of FGFR1–3) and ponatinib (blocks all the FGFR isoforms) elicited potent anti-tumor activities in preclinical investigations so they are currently being evaluated in clinical trials. Those inhibitors displayed the greatest potency in FGFR-driven cancer models, which may be attributed to the interference with the oncogenic functions of either amplified or constitutively active FGFR (Dutt et al., 2011; Zhao et al., 2011; Gavine et al., 2012; Gozgit et al., 2012). Accordingly, further studies are needed to evaluate the relative contribution of angiogenic versus oncogenic inhibitory mechanisms towards the overall anti-tumor activity. The allosteric antagonist of the FGFR, SSR128129E, showed a strong anti-angiogenic activity in addition to tumour growth and metastasis inhibitory effects in animal models of arthritis and cancer respectively. Because allosteric modulators leave a residual level of baseline signalling, they have the ability to fine-tune target biological responses. As a result, allosteric multi-FGFR inhibitors may have an improved benefit/risk ratio that is not attainable with the other TKIs (Bonoet al., 2013; Herbert et al., 2013). However, preclinical findings suggest that long-term clinical outcomes may improve with blockade of additional pro-angiogenic RTKs that may also reduce the risk of drug resistance (Hilberg et al., 2008). For example, dual inhibition of VEGFRs and FGFRs using brivanib produced enduring tumour stasis and angiogenic blockade following the failure of VEGF-targeted therapies (Allen et al., 2011). Furthermore, triple inhibition of FGFRs, VEGFRs and PDGFR(s) using dovitinib (TKI258) or nintedanib (BIBF 1120) displayed broad-spectrum anti-tumour activities in several tumour xenograft models as well as promising data in clinical trials. Combined inhibition of FGFR/VEGFR/PDGFR targets not only tumour cells, but also endothelial cells, pericytes and smooth muscle cells, resulting in an effective inhibition of tumour growth, angiogenesis and metastasis even in advanced tumour stages (Hilberg et al., 2008; Ledermann et al., 2011; Taeger et al., 2011; Chenet al., 2012; Angevin et al., 2013).

Oncogene-targeted therapy

Oncogenes, genes that cause the transformation of normal cells into cancerous cells, are thought to up-regulate many pro-angiogenic proteins. Therefore, anticancer drugs that were developed for their capacity to block an oncogene also have an indirect anti-angiogenic activity (Kerbel et al., 2000; Bergers and Benjamin, 2003; Folkman, 2003). For example, dasatinib and other inhibitors of sarcoma (Src), an aberrantly activated non-RTK associated with many human malignancies, showed potent anti-angiogenic effects through the down-regulation of VEGF and IL-8 (Summy et al., 2005; Han et al., 2006; Haura et al., 2010). Another example is to target the oncogenic Ras using farnesyl transferase (FT) inhibitors, which inhibit post-translational farnesylation of Ras that governs the latter’s activity (Awada et al., 2002). FT inhibitors were found to inhibit tumor VEGF expression and block FTase-dependent Ras activation, which is critically involved in VEGF-elicited angiogenic signal transduction and angiogenesis (Han et al., 2005; Izbicka et al., 2005; Kim et al., 2010). In addition to classical oncogenes inhibition, interference with other tumor-deregulated signaling pathways would offer another approach in targeting angiogenesis. For example, inhibitors of heat shock protein 90 (HSP90), a chaperone molecule known to protect oncoproteins from misfolding and degradation in the protein-rich intracellular environment, were found to prevent VEGF production and to disrupt multiple pro-angiogenic signalling pathways in numerous cancer cells. They were also shown to inhibit tumour growth and vascularity of different human tumor xenografts (Sanderson et al., 2006; Langet al., 2007; Eccles et al., 2008; Trepel et al., 2010; Moser et al., 2012). Proteasome inhibitors, such as bortezomib (PS-341) or MG-132, were also shown to reduce tumour growth and vascularity of squamous cell carcinoma and pancreatic cancer xenograft probably through inhibition of NF–κB-dependent release of pro-angiogenic gene products, VEGF and IL-8 (Sunwoo et al., 2001; Nawrocki et al., 2002; Matsuo et al., 2009). Similarly, inhibition of B-cell lymphoma 2 (Bcl-2), a prosurvival protein that regulates apoptosis by preventing the mitochondrial release of pro-apoptogenic factors, was shown to prevent NF-κB-mediated release of the pro-angiogenic factors IL-8 and CXC chemokine ligand 1 (CXCL1) as well as VEGF in tumor-associated endothelial cells and pancreatic cell lines respectively (Karl et al., 2005; Wang et al., 2008). Moreover, (−)-gossypol, a natural BH3 mimetic that inhibits BH3 domain of Bcl-2 as well as related prosurvival proteins (Bcl-xL and Mcl-1), was shown to remarkably decrease microvessel density in human prostate tumour PC-3 xenografts through decrease of VEGF and IL-8 release as well as blocking multiple steps in VEGF-activated biological events (Karaca et al., 2008; Pang et al., 2011).

Matrix degrading and remodelling-targeted therapy

Matrix degrading and remodelling are activated by tumors to modify local micro-environment, which in turn promote their angiogenic potential (Bergers et al., 2000; Vlodavsky and Friedmann, 2001). Up-regulation of expression and activity of several endogenous MMPs including MMP-2, MMP-9 as well as MMP-3 and MMP-7 have been identified in invasive tumors (for a review, see Bourboulia and Stetler-Stevenson, 2010). Consequently, inhibitors of MMPs were extensively pursued as a therapeutic strategy for treating cancer. Unfortunately, MMPs intervention strategies had met with limited clinical success because of severe toxicities and associated metastasis-promoting effect (Coussens et al., 2002; Devy et al., 2009). Furthermore, the paradoxical roles of tissue inhibitors of metalloproteinases (TIMPs) may contribute to such failure depending on the net balance of TIMPs and MMPs in tumour stroma (Jiang et al., 2002). As a result, efforts were directed at therapies exploiting endogenous MMP inhibitors, TIMPs or monoclonal antibodies against individual MMPs (Martens et al., 2007; Jarvelainen et al., 2009). For example, DX-2400, a highly selective fully human MMP-14 inhibitory antibody, was found to block pro-MMP-2 processing on tumor and endothelial cells, inhibited angiogenesis, and slowed tumor progression and formation of metastatic lesions (Devy et al., 2009). Alternatively, in order to reduce toxicity and enhance drug delivery, polymeric nanoparticulate delivery systems could be used to target individual components of ECM. For example, targeted delivery of antisense inhibitors of laminin-8, a vascular basement membrane component, by conjugation to the natural drug carrier β-poly(L-malic acid) significantly reduced tumour microvessel density and increased animal survival in an experimental model of glioblastoma (Fujita et al., 2006). Similarly, a nano delivery system that incorporate peptides against proteolytically processed type IV collagen significantly accumulated in tumors and blocked angiogenesis in experimental models (Mueller et al., 2009). However, the highly sulfated oligosaccharides, Heparan (HS) mimetics highly sulfated oligosaccharides, were shown to have a heparanase-inhibiting effect sequestering, in turn, many heparan sulfate proteoglycan (HSPG)-binding factors (Johnstone et al., 2010; Dredge et al., 2011). In preclinical studies, HS mimetics have effectively targeted multiple HSPG-dependent functions and have resulted in decreased in vivo tumor growth, tumor invasion, tumor metastasis and angiogenesis (Johnstone et al., 2010; Dredge et al., 2011; Zhou et al., 2011). Clinically, the heparanase inhibitor PI-88 showed preliminary efficacy as an adjunct therapy for post-operative hepatocellular carcinoma (Liu et al., 2009).

Tumour-associated stromal cell-targeted therapy

Tumour-associated stromal cells crosstalk is a perquisite for the formation of a tumour vasculature, an essential step for tumour progression (Lorusso and Ruegg, 2008). Interference with those crosstalk circuits through intervention of cellular adhesion (highlighted in next paragraph) or tumor-induced recruitment of different stromal cells may be considered as an indirect way of anti-angiogenic therapy (Ferrara and Kerbel, 2005). The latter can be supported by studies in which inhibition of macrophage infiltration, for example, by either genetic ablation of the macrophage CSF-1 or liposomal clodronate-induced macrophage depletion, was shown to delay the angiogenic switch and malignant transition (Giraudo et al., 2004; Lin et al., 2006). Furthermore, CSF-1R kinase inhibitors were found to reduce tumor-associated vascularity in two different tumor mouse models (Kubota et al., 2009; Mantheyet al., 2009). In addition, clodronate and other related bisphosphonates, originally used to treat skeletal complications in patients with tumour-induced osteolysis, were shown to exert potent anti-tumour and anti-angiogenic effects in many other studies (Fournier et al., 2002; Santini et al., 2003; Stathopoulos et al., 2008). Zoledronic acid, a third-generation bisphosphonate, was also found to reduce a number of tumour-associated macrophages and shift their phenotype from M2 to M1, resulting in a reduction in TAM-associated production of VEGF in murine models of spontaneous mammary carcinogenesis and mesothelioma (Coscia et al., 2010; Veltman et al., 2010). Clinically, repeated low-dose therapy with zoledronic acid, which maintains active drug plasma concentration, was able to induce an early remarkable and long-lasting decrease of VEGF levels in patients with cancer (Santini et al., 2007). In another example, inhibition of mobilization of neutrophils, from bone marrow and their infiltration into tumour, using neutralizing anti–prokineticin-2, an antibody against a secreted protein known also as BV8, was shown to impair the initial angiogenic switch in a multistage pancreatic beta cell tumorigenesis model (Shojaei et al., 2008). Furthermore, the neutralizing anti-BV8 was found to prevent myeloid cell-dependent tumour angiogenesis in several xenograft models (Shojaei et al., 2007). Cancer-associated fibroblasts (CAF) can also be targeted with thapsigargin analogue coupled with peptides specific for fibroblast activation protein (FAP), a CAF membrane-bound protease whose catalytic site has access to the peritumoural fluid of the tumor micro-environment. This extracellular activation results in the death of CAFs as well as pericytes and endothelial cells within milieu of different human tumor xenografts (Brennen et al., 2012).

Cell adhesion molecules (CAMs)-targeted therapy

CAMs are cell surface proteins known to be involved in binding with other counter-receptors on adjacent cells or surrounding ECM macromolecules (Aplin et al., 1998). Many CAMs, such as αv-integrins, E-selectin, N-cadherin and VE-cadherin, have been implicated in tumour angiogenesis (Bischoff, 1997; Tei et al., 2002; Nakashima et al., 2003; Weis and Cheresh, 2011). For example, αv-integrins are expressed on surface of endothelial cells and can determine whether cells can adhere to and survive in a particular micro-environment. A number of matrix-derived fragments have the ability to act as endogenous angiogenesis inhibitors through binding to integrins on endothelial cells, disrupting physical connections and suppressing signalling events associated with cell survival, migration and proliferation (Nyberg et al., 2005). Consequently, integrins antagonism using peptidomimetics (e.g. cilengitide), monoclonal antibodies (e.g. volociximab) or oral small-molecule compounds have been investigated in a wide range of malignancies (Huveneers et al., 2007). Cilengitide is a cyclized pentapeptide peptidomimetic designed to compete for the arginine-glycine-aspartic acid (RGD) peptide sequence, thereby blocking the ligation of the αvβ3 and αvβ5 integrins to matrix proteins (Hariharan et al., 2007). Cilengitide is mainly under clinical development for glioblastoma; however, clinical trials of other malignancies such as head and neck cancer as well as lung cancer were also initiated (Reardon and Cheresh, 2011; Vermorken et al., 2012; Manegold et al., 2013). Alternatively, cyclic peptides containing RGD motif could guide nanoparticulate delivery system, which incorporates anti-angiogenic cytotoxic agents such as doxorubicin, paclitaxel or combretastatin A4, to accumulate specifically in tumor vasculature with no overt systemic toxicity (Murphy et al., 2008; Ruoslahti et al., 2010; Wang et al., 2011). Volociximab, a chimeric humanized monoclonal antibody that selectively inhibits the αvβ1 integrin interaction with fibronectin, has been evaluated also in clinical trials for solid tumours such as renal cell carcinoma, recurrent ovarian cancer, advanced non–small-cell lung cancer and metastatic pancreatic cancer (Figlin et al., 2006; Evans et al., 2007; Jarvelainen et al., 2009; Vergote et al., 2009; Besse et al., 2013). Cadherins constitute a superfamily of molecules that mediate calcium-dependent cell–cell adhesions. The intracellular domains of cadherins directly bind to β-catenin and link with cytoskeletal components, providing the molecular basis for stable cell–cell adhesion (Zhang et al., 2010). Targeting cadherin signalling may also represent another way for tumor angiogenesis intervention. For example, ADH-1, a cyclic pentapeptide containing the cell adhesion recognition site (His-Ala-Val) required for N-cadherin adhesion, was shown to possess anti-angiogenic and anti-tumour activity (Blaschuk et al., 2005; Blaschuk, 2012). Similarly, monoclonal antibody directed against specific region of VE-cadherin was able to inhibit tumor angiogenesis and growth with no side effects on normal vasculature (Corada et al., 2002; May et al., 2005).

Inflammatory angiogenesis-targeted therapy

Targeting inflammatory angiogenesis, responsible for a substantial part of tumour vascularization initiated by infiltrating leukocytes, may be considered as another indirect anti-angiogenic strategy (Albini et al., 2005). Moreover, as mentioned before, tumour-infiltrating leukocytes contribute into malignant progression through production of many pro-inflammatory cytokines, chemokines and enzymes that can mostly induce angiogenic cascade (Balkwill et al., 2005). Such vital roles have been supported by the early observation that nonsteroidal anti-inflammatory drugs can inhibit tumour angiogenesis and, in turn, tumor progression (Albini et al., 2005). For example, ibuprofen was found to decrease tumor growth and metastatic potential in mice models through modulation of angiogenesis (Yao et al., 2005). Moreover, selective inhibitors of COX-2, an inducible enzyme that catalyses the production of prostanoids from arachidonic acid, were also shown to inhibit angiogenesis (Tsujii et al., 1998; Wei et al., 2004). The anti-angiogenic effect of COX-2 inhibitors may be contributed, in part, by decreasing the COX-2 metabolic product PGE2, the predominant PG in solid tumors known to stimulate cancer cells to produce pro-angiogenic factors such as VEGF and bFGF as well as many other factors belonging to CXC chemokines family (Strieter et al., 2004; Wang et al., 2006; Wang and Dubois, 2010). Members of the CXC chemokine family are heparin-binding proteins that possess disparate regulative roles in angiogenesis. For example, the ELR+ CXC chemokines, characterized by highly conserved three amino acid motifs (Glu-Leu-Arg; ‘ELR’ motif), are potent promoters of angiogenesis, whereas the IFN-inducible (ELR−) CXC chemokines are inhibitors of angiogenesis (Strieter et al., 2004). The use of repertaxin, originally designed to target the ELR+ CXC chemokine receptors CXCR1 and CXCR2 on neutrophils to prevent their migration to sites of inflammation, was found to inhibit tumor angiogenesis, thereby suppressing tumour progression in a genetic model of pancreatic ductal adenocarcinoma (Ijichi et al., 2011). It would be beneficial to explore other small-molecule CXCR2 antagonists that have already been developed for the treatment of inflammatory diseases in different preclinical models of cancer, especially inflammation-associated cancers (refer to Chapman et al., 2009 for a list of newly developed CXCR2 antagonists used in the treatment of inflammatory diseases of the lung).

Mechanisms of enhanced therapeutic efficacy

  • Dual targeting of tumor vasculature
  • Targeting different cell types of tumor micro-environment
  • Normalization of tumor vasculature
  • Chemosensitization of tumor cells
  • Interference with the repair of cytotoxic drug-induced damage and resistance mechanisms

Consequences of anti-angiogenic therapy with other anticancer therapy

  • Contrary to initial expectations, treatment with angiogenesis inhibitors was associated with unexpected toxicities. The toxicity profiles of those inhibitors reflect the systemic disturbance of growth factor signalling pathways that mediate their anti-angiogenic activity (Elice and Rodeghiero, 20102012). In this context, disturbance of the tight endothelial cell-platelet interaction that maintains vascular integrity results in bleeding complications, gastrointestinal perforations, and disturbed wound and ulcer healing (Verheul and Pinedo, 2007). In general, the incidence of those adverse effects increases when anti-angiogenic agent is combined with chemotherapy. For example, bleeding complications have been observed in patients with colorectal cancer treated with chemotherapy in combination with bevacizumab (Kabbinavar et al., 2003; Giantonio et al., 2006). In non–small-cell lung cancer, some patients treated with bevacizumab in combination with carboplatin and paclitaxel experienced severe or fatal pulmonary haemorrhage (Johnson et al., 2004). Furthermore, a higher incidence of gastrointestinal perforation was observed in patients with colorectal cancer given bevacizumab in combination with chemotherapy compared with chemotherapy alone (Hurwitz et al., 2004). Similarly, thrombotic events have been observed in patients treated with angiogenesis inhibitors, especially when these agents are given in combination with chemotherapy (Verheul and Pinedo, 2007). Treatment of patients with cancer with angiogenesis inhibitors is frequently associated with hypertension, which may require the addition of regular anti-hypertensive agent (Izzedine et al., 2009).

Summary and future directions

  • Angiogenesis is a critical process that occurs pathologically in many malignancies due to changing balance of endogenous angiogenesis inducers and inhibitors, leading to the activation of nearby endothelial cells to form new vasculature. Consequently, angiogenesis can be targeted to restrict initiation, growth and progression of most of angiogenesis-dependent malignancies. Numerous angiogenic inhibitors have been identified, some of which are currently being investigated in clinical trials and some others were even approved for cancer therapies. These angiogenesis inhibitors were classified based on their target into two main classes: direct and indirect inhibitors. Indirect angiogenesis inhibitors can be further subclassified based on their interference mechanisms with the angiogenic cascade. A list of major categories and molecular targets for angiogenesis inhibitors is shown in Table 2.
  • Most angiogenesis inhibitors conferred clinical benefits mainly when combined with other chemotherapeutic/targeted therapies rather than being used as monotherapy. Unfortunately, many anti-angiogenic agents were shown to be associated with overt systemic toxicity as well as resistance emergence and disease recurrence. Drug resistance in anti-angiogenic therapy may result from a plethora of pro-angiogenic factors released by inappropriately functioning host cells in the tumor micro-environment as a compensatory mechanism. Therefore, the strategy of targeting endothelial cells alone may not be enough as explained in the previous texts, requiring the proposal of different rationales in which other cellular compartments of tumor micro-environment are targeted to attain proper anti-angiogenic and anti-tumor response. That highlights the importance of considering tumor micro-environment as a dynamic system, as depicted in Figure 1 in which interference with any of its components may be an approach to interfere with cancer hallmarks, including angiogenesis.

9.5.5 LUCITANIB a VEGFR/FGFR dual kinase inhibitor in Phase 2 trials

Dr.  Anthony Melvin Crasto

source: http://medcheminternational.blogspot.com/2015/01/lucitanib-vegfrfgfr-dual-kinase.html

Lucitanib.png
LUCITANIB
6-[7-[(1-aminocyclopropyl)methoxy]-6-methoxyquinolin-4-yl]oxy-N-methylnaphthalene-1-carboxamide
6-(7-((l-aminocyclopropyl)methoxy)-6-methoxyquinolin-4-yloxy)- N-methyl- 1 -naphthamide
1058137-23-7 (E-3810 free base); 1058137-84-0  (E-3810 HCl salt)
E-3810, E-3810 amine, UNII-PP449XA4BH, E3810, Lucitanib [INN], AL3810
Molecular Formula:C26H25N3O4
Molecular Weight:443.4944 g/mol
PATENT SUBMITTED GRANTED
Spiro Substituted Compounds As Angiogenesis Inhibitors [US8163923] 2008-09-18 2012-04-24
A 4-(3-methoxypropoxy)-3-methylpyridinyl derivative of timoprazole that is used in the therapy of STOMACH ULCERS and ZOLLINGER-ELLISON SYNDROME. The drug inhibits H(+)-K(+)-EXCHANGING ATPASE which is found in GASTRIC PARIETAL CELLS.
For in advanced solid tumors.
Lucitanib (E-3810): Lucitanib, also known as E-3810,  is a novel dual inhibitor targeting human vascular endothelial growth factor receptors (VEGFRs) and fibroblast growth factor receptors (FGFRs) with antiangiogenic activity. VEGFR/FGFR dual kinase inhibitor E-3810 inhibits VEGFR-1, -2, -3 and FGFR-1, -2 kinases in the nM range, which may result in the inhibition of tumor angiogenesis and tumor cell proliferation, and the induction of tumor cell death. Both VEGFRs and FGFRs belong to the family of receptor tyrosine kinases that may be upregulated in various tumor cell type
Lucitanib (E-3810) Structure

Overview

Lucitanib is an oral, potent inhibitor of the tyrosine kinase activity of fibroblast growth factor receptors 1 through 3 (FGFR1-3), vascular endothelial growth factor receptors 1 through 3 (VEGFR1-3) and platelet-derived growth factor receptors alpha and beta (PDGFR α-ß). We own exclusive development and commercial rights to lucitanib on a global basis, excluding China. Lucitanib rights to markets outside of the U.S. and Japan have been sublicensed to Les Laboratoires Servier (Servier). We are collaborating with Servier on the global clinical development of lucitanib.

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Nonhematological cancers [4.2]

Writer and Curator: Larry H. Bernstein, MD, FCAP 

http://dx.doi.org:/2015/04/30/lhbern/nonhematological-cancers

Characteristics and Types

Tumors are considered to be cell growths that are either benign or malignant proliferations. Those that are benign may be reactive, but they do not have the characteristics of a malignancy.  The main features we are concerned with are:

  1. Cancer cells utilize glucose by the anaerobic glycolysis energy pathway as the primary energy source, and this is despite a sufficient supply of oxygen. This characteristic is referred to as the Warburg Effect, as it was originally described by Otto Warburg in the 1920s, and he had derived a parallel to the observations of yeast cells by Louis Pasteur 60 years earlier.
  2. Cancer cells proliferate and take on features common to cancer cells and less characteristic in expression than the cells of origin.
  3. Cancer cells loose the properties of cell-cell attachment, and this is associated with metastasis to proximate or to distant sites.
  4. As a result of Warburg’s original studies, he concluded that cancer cells have impaired respiration (mitochondria were not yet described).
  5. It would be known much later that there is an impairment of the balance between cell repair and cell death.
  6. Malignant tumors are divided into solid tumors and hematological malignancies. This discussion is focused only on malignant solid tumors.
  7. The types of cancer can be classified according to the tissue of origin: mesenchymal (sarcoma) and epithelial (carcinoma), and by source of origin:

Brain Cancer
Breast Cancer
Kidney Cancer
Lung Cancer
Ovarian Cancer
Pancreatic Cancer
Prostate Cancer
Stomach Cancer

There are many studies showing positive associations between solid tumors and pesticide exposure. In particular, the large well-designed cohort studies consistently show statistically significant positive associations. The relationships are most consistent for high exposure levels such as those found in occupational settings. The results frequently show dose response relationships, and quality of studies was generally good. Overall, these findings strongly support a reduction of pesticide use, particularly for those individuals with occupational exposure (agriculture, pesticide applicators) at high doses.
Otto Warburg called attention to this in the 1950’s. However, we also know that viruses can have a role in the causation of cancers. Moreover, cancers may occur in sites of chronic inflammation.  I have not said anything about the association of specific mutations with types of cancer, and associations in some cases with specific populations at a greater risk than the broader population.

Profiling Solid Tumor Heterogeneity by LCM and Biological MS of Fresh-Frozen Tissue Sections

Donald J. Johann, Sumana Mukherjee, DaRue A. Prieto, Timothy D. Veenstra, Josip Blonder
Laser Capture Microdissection
Methods in Molecular Biology 2011; 755, pp 95-106

The heterogeneous nature of solid tumors represents a common problem in mass spectrometry (MS)-based analysis of fresh-frozen tissue specimens. Here, we describe a method that relies on synergy between laser capture microdissection (LCM) and MS for enhanced molecular profiling of solid tumors. This method involves dissection of homogeneous histologic cell types from thin fresh-frozen tissue sections via LCM, coupled with liquid chromatography (LC)-MS analysis. Such an approach enables an in-depth molecular profiling of captured cells. This is a bottom-up proteomic approach, where proteins are identified through peptide sequencing and matching against a specific proteomic database. Sample losses are minimized, since lysis, solubilization, and digestion are carried out directly on LCM caps in buffered methanol using a single tube, thus reducing sample loss between these steps. The rationale for the LCM-MS coupling is that once the optimal method parameters are established for a solid tumor of interest, homogeneous histologic tumor/tissue cells (i.e., tumor proper, stroma, etc.) can be effectively studied for potential biomarkers, drug targets, pathway analysis, as well as enhanced understanding of the pathological process under study.

A microRNA expression signature of human solid tumors defines cancer gene targets

Stefano Volinia*†‡, George A. Calin*‡, Chang-Gong Liu*, et al.
PNAS  Feb 14, 2006; 103(7): 2257–2261
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1413718/pdf/pnas-0510565103.pdf

Small noncoding microRNAs (miRNAs) can contribute to cancer development and progression and are differentially expressed in normal tissues and cancers. From a large-scale miRnome analysis on 540 samples including lung, breast, stomach, prostate, colon, and pancreatic tumors, we identified a solid cancer miRNA signature composed by a large portion of overexpressed miRNAs. Among these miRNAs are some with well characterized cancer association, such as miR-17-5p, miR-20a, miR-21, miR-92, miR-106a, and miR-155. The predicted targets for the differentially expressed miRNAs are significantly enriched for protein-coding tumor suppressors and oncogenes (P < 0.0001). A number of the predicted targets, including the tumor suppressors RB1 (Retinoblastoma 1) and TGFBR2 (transforming growth factor, beta receptor II) genes were confirmed experimentally. Our results indicate that miRNAs are extensively involved in cancer pathogenesis of solid tumors and support their function as either dominant or recessive cancer genes.

Diagnosis of and therapy for solid tumors with radiolabeled antibodies and immune fragments

Carrasquillo JA, Krohn KA, Beaumier P, McGuffin RW, et al.
Cancer Treatment Reports [1984, 68(1):317-328]
http://europepmc.org/abstract/med/6607111

Antibodies which are directed against human tumor-associated antigens can potentially be used as carriers of radioactivity for in vivo diagnosis (radioimmunodetection) or treatment (radioimmunotherapy) of solid tumors, including colon, hepatomacholangiocarcinoma,  and melanoma.  Murine  monoclonal antibodies (MOAB), produced by the hybridoma technique of Kohler and Milstein, are replacing conventional heterosera as sources of antibodies, because MOAB can be produced in large quantities as reproducible reagents with homogeneous binding properties. We have studied  human melanoma using MOAB IgG and Fab fragments that recognize the human melanoma-associated antigens p97and “high-molecular-weight antigen.” Both antigens are found in the membrane of melanomas at much larger concentrations than in normal adult tissues. We have performed radioimmunodetection studies with whole immunoglobulin and have detected 88% of lesions greater than 1.5 cm. We have used Fab fragments for radioimmunotherapy and have found that large doses of radiolabeled antibodies (up to 342 mCi) can be repetitively given to patients without excessive end-organ toxicity. Two of three patients treated with high-dose radiolabeled antimelanoma Fab showed an effect from the treatment. Although both technical and biologic problems remain, the use of radiolabeled antibodies that are directed against tumor-associated antigens holds future promise as a new therapeutic approach to solid tumors that are resistant to conventional therapy.

https://www.cirm.ca.gov/our-progress/disease-information/solid-tumor-fact-sheet

Solid tumors include cancers of the brain, ovary, breast, colon and other tissues. Many people believe that one quality solid tumors share is a reliance on cancer stem cells. These cancer stem cells are thought to divide to produce the bulk of the cells that make up the tumor.

The hypothesis suggests that unlike most cells of a tumor, the cancer stem cells divide very slowly and are less likely to be destroyed by chemotherapies that kill the fast-growing tumor cells. The thought is that cancers might recur because the chemotherapy kills the bulk of the tumor, but leaves behind the cancer stem cells that can, over time, form a new tumor.

Stem cell scientists are studying cancer stem cells from solid tumors in the lab to find ways of destroying them. If these cancer stem cells share characteristics that allow them to be destroyed by the same drug, then a single new drug could significantly improve cancer treatment for a range of different cancer types.

Resminostat – by 4SC

Despite decades of concentrated effort, medicine has yet to achieve a decisive breakthrough for many types of cancer. 4SC is focusing on fields of research with an especially high academic interest and future potential – such as epigenetics, cancer stem cells, cancer immunotherapy and other key molecular signal transduction pathways that contribute to the development and persistence of cancer diseases.

Resminostat is 4SC’s lead oncology compound. Resminostat is an oral histone-deacetylase (HDAC) inhibitor with an innovative epigenetic mechanism of action that potentially enables the compound to be deployed as a novel, targeted tumour therapy for a broad spectrum of oncological indications, both as a monotherapy and, in particular, in combination with other cancer drugs.

Epigenetic mode of action

HDAC inhibitors modify the three-dimensional chromatin DNA structure of tumour cells and can trigger cell differentiation, which can ultimately result in programmed cell death (apoptosis). HDAC inhibitors therefore offer a mechanism of action that has the potential to halt tumour progression and induce tumour regression. Furthermore, resminostat – due to its epigenetic mode of action – can develop an additional synergetic effect in combined treatments with other traditional cancer therapies and also fight the development of resistance to other cancer medications.

An example: In preclinical studies, resminostat has been shown to effectively inhibit epithelial-mesenchymal transition (EMT). EMT, which may be promoted through the administration of certain conventional cancer therapies, leads to the formation of particularly aggressive tumour cells, which ultimately may result in greater proliferation of cancer cells in patients and the patients’ death.

On the whole, a reinforcing positive therapeutic effect is expected to be achieved through well-tolerated parallel administration of an epigenetic compound such as resminostat and a traditional cancer drug. Combination therapy thus aims to improve the success of the treatment as a whole.

Resminostat – by 4SC in Europe and its Japanese development partner Yakult Honsha in Asia – has been investigated to date in a broad clinical Phase I/II program in the four indications of liver cancer (hepatocellular carcinoma, HCC), Hodgkin Lymphoma (HL), colorectal cancer (CRC), and non-small-cell lung cancer (NSCLC).

Notably, in both tumor indications, HCC and HL, gene expression levels of the new biomarker ZFP64 measured prior to study treatment start in blood cells of patients, were identified to be indicative of survival outcome upon treatment with resminostat. Hereby, the set of patients with a high level of ZFP64 gene expression at baseline showed a statistically significant increase of median overall survival compared with patients with low ZFP64 expression levels.

4SC is prioritizing the further development of resminostat in the liver cancer indication. 4SC’s goal is to progress resminostat in combination with sorafenib as a first-line therapy for HCC until market approval. 4SC’s main focus is the use of the resminostat/sorafenib combination as a first-line treatment for HCC patients, while the use as a second-line therapy remains an attractive additional option.

4SC Discovery is a drug discovery company based in Planegg-Martinsried near Munich. It was founded in December 2011 as a wholly owned subsidiary of 4SC AG.

Response Evaluation Criteria in Solid Tumors
http://en.wikipedia.org/wiki/Response_Evaluation_Criteria_in_Solid_Tumors

Response Evaluation Criteria In Solid Tumors (RECIST) is a set of published rules that define when tumors in cancer patients improve (“respond”), stay the same (“stabilize”), or worsen (“progress”) during treatment. The criteria were published in February 2000 by an international collaboration including the European Organisation for Research and Treatment of Cancer (EORTC), National Cancer Institute of the United States, and the National Cancer Institute of Canada Clinical Trials Group. Today, the majority of clinical trials evaluating cancer treatments for objective response in solid tumors use RECIST.

These criteria were developed and published in February 2000, and subsequently updated in 2009. They are specifically NOT meant to determine whether patients have improved or not, as these are tumor-centric, not patient centric criteria. This distinction must be made by both the treating physicians and the cancer patients themselves. Many oncologists in their daily clinical practice follow their patient’s malignant disease by means of repeated imaging studies and make decisions about continuing therapy on the basis of both objective and symptomatic criteria. It is not intended that these RECIST guidelines play a role in that decision making, except if determined appropriate by the treating oncologist.

  • CT and MRI are the best currently available and reproducible methods to measure target lesions selected for response assessment. Conventional CT and MRI should be performed with cuts of 10 mm or less in slice thickness contiguously. Spiral CT should be performed using a 5 mm contiguous reconstruction algorithm. This applies to tumors of the chest, abdomen and pelvis. Head and neck tumors and those of extremities usually require specific protocols.
  • Lesions on chest X-ray are acceptable as measurable lesions when they are clearly defined and surrounded by aerated lung. However, CT is preferable.
  • When the primary endpoint of the study is objective response evaluation, ultrasound (US) should not be used to measure tumor lesions. It is, however, a possible alternative to clinical measurements of superficial palpable lymph nodes, subcutaneous lesions and thyroid nodules. US might also be useful to confirm the complete disappearance of superficial lesions usually assessed by clinical examination.
  • The utilization of endoscopy and laparoscopy for objective tumor evaluation has not yet been fully and widely validated. Their uses in this specific context require sophisticated equipment and a high level of expertise that may only be available in some centers. Therefore, the utilization of such techniques for objective tumor response should be restricted to validation purposes in specialized centers. However, such techniques can be useful in confirming complete pathological response when biopsies are obtained.
  • Tumor markers alone cannot be used to assess response. If markers are initially above the upper normal limit, they must normalize for a patient to be considered in complete clinical response when all lesions have disappeared.
  • Cytology and histology can be used to differentiate between PR and CR in rare cases (e.g., after treatment to differentiate between residual benign lesions and residual malignant lesions in tumor types such as germ cell tumors).

Baseline documentation of “Target” and “Non-Target” lesions

  • All measurable lesions up to a maximum of 2 lesions per organ and 5 lesions in total, representative of all involved organs should be identified as target lesions and recorded and measured at baseline.
  • Target lesions should be selected on the basis of their size (lesions with the longest diameter) and their suitability for accurate repeated measurements (either by imaging techniques or clinically).
  • A sum of the longest diameter (LD) for all target lesions will be calculated and reported as the baseline sum LD. The baseline sum LD will be used as reference by which to characterize the objective tumor response.
  • All other lesions (or sites of disease) should be identified as non-target lesions and should also be recorded at baseline. Measurements of these lesions are not required, but the presence or absence of each should be noted throughout follow-up.

Response Criteria

Evaluation of target lesions

  • Complete Response (CR): Disappearance of all target lesions
  • Partial Response (PR): At least a 30% decrease in the sum of the LD of target lesions, taking as reference the baseline sum LD
  • Stable Disease (SD): Neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for PD, taking as reference the smallest sum LD since the treatment started
  • Progressive Disease (PD): At least a 20% increase in the sum of the LD of target lesions, taking as reference the smallest sum LD recorded since the treatment started or the appearance of one or more new lesions

Evaluation of non-target lesions

  • Complete Response (CR): Disappearance of all non-target lesions and normalization of tumor marker level
  • Incomplete Response/ Stable Disease (SD): Persistence of one or more non-target lesion(s) or/and maintenance of tumor marker level above the normal limits
  • Progressive Disease (PD): Appearance of one or more new lesions and/or unequivocal progression of existing non-target lesions

Evaluation of best overall response

The best overall response is the best response recorded from the start of the treatment until disease progression/recurrence (taking as reference for PD the smallest measurements recorded since the treatment started). In general, the patient’s best response assignment will depend on the achievement of both measurement and confirmation criteria

  • Patients with a global deterioration of health status requiring discontinuation of treatment without objective evidence of disease progression at that time should be classified as having “symptomatic deterioration”. Every effort should be made to document the objective progression even after discontinuation of treatment.
  • In some circumstances it may be difficult to distinguish residual disease from normal tissue. When the evaluation of complete response depends on this determination, it is recommended that the residual lesion be investigated (fine needle aspirate/biopsy) to confirm the complete response status.

Duration of stable disease

  • SD is measured from the start of the treatment until the criteria for disease progression are met, taking as reference the smallest measurements recorded since the treatment started.
  • The clinical relevance of the duration of SD varies for different tumor types and grades. Therefore, it is highly recommended that the protocol specify the minimal time interval required between two measurements for determination of SD. This time interval should take into account the expected clinical benefit that such a status may bring to the population under study.

Response review

  • For trials where the response rate is the primary endpoint it is strongly recommended that all responses be reviewed by an expert(s) independent of the study at the study’s completion. Simultaneous review of the patients’ files and radiological images is the best approach.

Tumor microenvironment

http://en.wikipedia.org/wiki/Tumor_microenvironment

The tumor microenvironment is the cellular environment in which the tumor exists, including surrounding blood vessels, immune cells, fibroblasts, other cells, signaling molecules, and the extracellular matrix(ECM).[1] The tumor and the surrounding microenvironment are closely related and interact constantly. Tumors can influence the microenvironment by releasing extracellular signals, promoting tumor angiogenesisand inducing peripheral immune tolerance, while the immune cells in the microenvironment can affect the growth and evolution of cancerous cells, such as in immuno-editing. The tumor microenvironment has been shown to contribute to tumour heterogeneity. In one of its earliest forms, this concept of interplay between the tumor and its microenvironment can be seen in Stephen Paget‘s “seed and soil” theory where he postulated that metastases of a particular type of cancer (“the seed”) often metastasizes to certain sites (“the soil”) based on the similarity of the environments of the original and secondary tumor sites.[2] Later, experiments by Halachmi and Witz in mice showed that for the same cancer cell line, inoculation in mice (where the tumor microenvironment could affect the cancer) created greater tumorigenicity than the same strain inoculated in in vitro culture.[3][4]

80-90% of cancer are carcinomas, or cancers that form in the epithelial tissue.[5] This tissue is not vascularized, which prevents tumors from growing greater than 2mm in diameter without recruiting new blood vessels to feed itself.[6] The process of angiogenesis is dysregulated to feed the cancer cells, and as a result the vasculature formed differs from that of normal tissue.

The enhanced permeability and retention effect (EPR effect) is the observation that the vasculature of tumors is often leaky and accumulates molecules in the blood stream to a greater extent than normal tissue. This effect linked to inflammation is not only seen in tumors, but in hypoxic area of cardiac muscles following a myocardial infarction (MI or heart attack).[7][8] This leaky vasculature is thought to have several causes, including a dearth of pericytes and a malformed basement membrane.[8

The tumor microenvironment is often hypoxic. As the tumor mass increases, the interior of the tumor grows farther away from existing blood supply. While angiogenesis can reduce this affect, the partial pressure of oxygen is below 5 mm Hg (venous blood has a partial pressure of oxygen at 40 mm Hg) in more than 50% of locally advanced solid tumors.[9][10] The hypoxic environment leads to genetic instability, which is associated with cancer progression, via downregulating nucleotide excision repair (NER) and mismatch repair (MMR) pathways.[11] Hypoxia also causes the upregulation of hypoxia-inducible factor 1 alpha (HIF1-α), which induces angiogenesis, and is associated with poorer prognosis and the activation of genes associated with metastasis.[10]

While a lack of oxygen can cause glycolytic behavior in cells, tumor cells have also been shown to undergo aerobic glycolysis as well, in which they preferentially produce lactate from glucose even when there is abundant oxygen. This phenomenon is called the Warburg effect, in honor of its discoverer, Otto Warburg.[12] No matter the cause, this leaves the extracellular microenvironment acidic (pH 6.5-6.9), while the cancer cells themselves are able to remain neutral (ph 7.2-7.4). It has been shown that this induces greater cell migration in vivo and in vitro, possibly by promoting degradation of the ECM.[13][14]

The stroma of a carcinoma is the connective tissue below the basal lamina. This includes fibroblasts, ECM, immune cells, and other cells and molecules. The stroma surrounding a tumor often reacts to the intrusion via inflammation, similar to how it might with a wound, leading cancer to be called “wounds that do not heal.”[15] Inflammation can encourage angiogenesis, speed the cell cycle, and prevent cell death, all of which augments tumor growth.

Carcinoma associated fibroblasts (CAFs) are a heterogenous group of fibroblasts whose function is pirated by cancer cells and then contribute toward carcinogenesis[17] These cells usually are derived from the normal fibroblasts in the surrounding stroma but can also come from pericytes, smooth muscle cells, fibrocytesmesenchymal stem cells (MSCs, often derived from bone marrow), or via epithelial-mesenchymal transition (EMT) or endothelial-mesenchymal transition (EndMT).[18][19][20] Unlike their normal counterparts, CAFs do not retard cancer growth in vitro.[21] Beyond simply lacking the ability of tumor inhibition, CAFs also perform several functions which support tumor growth, such as secreting vascular endothelial growth factor (VEGF), fibroblast growth factors (FGFs), platelet-derived growth factor (PDGF), and other pro-angiogenic signals to induce angiogenesis.[9] CAFs can also secrete transforming growth factor beta (TGF-β), which is associated with EMT, a process by which cancer cells can metastasize,[22] and is associated with inhibiting cytotoxic T cells and natural killer T cells.[23] As fibroblasts, CAFs are able to rework the ECM to include more paracrine survival signals such as IGF-1 and IGF-2, thus promoting survival of the surrounding cancer cells.[17] CAFs are also associated with the Reverse Warburg Effect where the CAFs perform aerobic glycolysis and feed lactate to the cancer cells.[17]

Several markers are used to identify CAFs including expression of α smooth muscle actin (αSMA), vimentinplatelet-derived growth factor receptor α (PDGFR-α), platelet-derived growth factor receptor β (PDGFR-β), fibroblast specific protein 1 (FSP-1), and fibroblast activation protein (FAP).[19] None of the factors can be used to differentiate CAFs from all other cells by itself.

Myeloid-derived suppressor cells (MDSCs) are a heterogenous population of cells of myelogenous origin with the potential to repress T cell responses. They regulate wound repair and inflammation and are rapidly expanded in cancer, correlating with that signs of inflammation are seen in most if not all tumor sites.[24][25] Tumors can produce exosomes that stimulate inflammation via MDSCs.[26][27] This group of cells include some tumor associated macrophages (TAMs).[24] TAMs are a central component in the strong link between chronic inflammation and cancer. TAMs are recruited to the tumor as a response to cancer associated inflammation.[28] Unlike normal macrophages, TAMs lack cytotoxic activity.[29] TAMs have been induced in vitro by exposing macrophage progenitors to different immune regulatory cytokines, such as interleukin 4(IL-4) and interleukin 13 (IL-13).[17] TAMs gather in necrotic regions of tumors where they have been associated with hiding the cancer cells from normal immune cells by secreting interleukin 10 (IL-10),[30] aiding angiogenesis by secreting vascular endothelial growth factor(VEGF) and nitric oxide synthase(NOS),[9] supporting tumor growth by secreting epidermal growth factor (EGF)[30] and remodeling the ECM.[9] TAMs show sluggish NF-κB activation, which allows for the smoldering inflammation seen in cancer.[31] An increased amount of TAMs is associated with worse prognosis.[32][33] TAMs represent a potential target for novel cancer therapies.

TAMs have recently been associating with using exosomes (vesicles used by mammalian cells to secrete intracellular contents) to deliver invasion-potentiating microRNA (miRNA) into cancerous cells, specifically breast cancer cells.[26][34]

Fibroblasts are in charge of laying down most of the collagens, elastin, glycosaminoglycans, proteoglycans (e.g. perlecan), and glycoproteins in the ECM. As many fibroblasts are transformed into CAFs during carcinogenesis, this reduces the amount of ECM produced and the ECM that is produced can be malformed, like collagen being loosely woven and non-planar, even curved.[37] In addition, CAFs produce matrixmatrix metalloproteinases (MMP), which cleave the proteins within the ECM.[9] CAFs are also able to disrupt the ECM via force, generating a track that a carcinoma cell can follow directly behind.[38] In either case, destruction of the ECM allows cancer cells to escape from their in situ location and intravasate into the blood stream where they can metastasize systematically. It can also provide passage for endothelial cells to complete angiogenesis to the tumor site.

Destruction of the ECM also modulates the signaling cascades controlled by the interaction of cell-surface receptors and the ECM, and it also reveals binding sites previously hidden, like the integrin alpha-v beta-3(αVβ3) on the surface of melanoma cells can be ligated to rescue the cells from apoptosis after degradation of collagen.[39][40] In addition, the degradation products may have downstream effects as well that can increase tumorigenicity of cancer cells and can serve as potential biomarkers.[39] The destruction of the ECM also releases the cytokines and growth factors stored therein (for example, VEGF, basic fibroblast growth factor (bFGF), insulin-like growth factors (IGF1 and IGF2), TGF-β, EGF, heparin-binding EGF-like growth factor (HB-EGF), and tumor necrosis factor (TNF), which can increase the growth of the tumor.[37][41]Cleavage of ECM components can also release cytokines that inhibit tumorigenesis, such as degradation of certain types of collagen can form endostatin, restin, canstatin, & tumstatin, which have antiangiogenic functions.[37]

Stiffening of the ECM is associated with tumor progression.[42] This stiffening may be partially attributed to CAFs secreting lysyl oxidase (LOX), an enzyme that cross-links the collagen IV found in the ECM.[19][43]

Numerous high throughput screens for cancer therapeutics are performed in vitro on cancer cell lines without the accompanying microenvironment, but current studies are also investigating the effects of supportive stroma cells on the biology of cancer cells and their resistance to therapy.[44] These studies revealed that there are interesting therapeutic targets in the microenvironment like integrins or chemokines.[44] These were missed by initial screens for anti-cancer drugs and might also help explain why so few initially identified drugs are highly potent in vivo.

Much effort has been devoted into developing nanocarrier vehicles (~20-200 nm in diameter) for transportation of drugs and other therapeutic molecules, so that these therapies can be targeted to selectively extravasate through tumor vasculature via the EPR effect. Using a nanocarrier is now considered the gold standard of targeted cancer therapy because it targets almost all tumors besides those few that are hypovascularized, like prostate and pancreatic tumors.[8][45] These efforts include protein capsids[46] and liposomes.[47] However, as some important, normal tissues, like the liver and kidneys, also have fenestrated endothelium, great care must be taken with using the correct size (10-100 nm, with greater retention in tumors seen in using larger nanocarriers) and charge (anionic or neutral).[8] Lymphatic vessels do not usually develop with the tumor, leading to increased interstitial fluid pressure, which made abrogate the journey of these nanocarriers to the tumor.[8][48]

Bevacizumab is clinically approved to treat a variety of cancer by targeting VEGF-A, which is produced by both CAFs and TAMs, thus slowing angiogenesis. Many other small molecule inhibitors exist that block the receptors for the growth factors released, thus making the cancer cell deaf to much of the paracrine signaling produced by CAFs and TAMs. These inhibitors include SunitinibPazopanibSorafenib, and Axitinib, all of which inhibit platelet derived growth factor receptors (PDGF-Rs) and VEGF receptors (VEGFRs). Cannabidiol, a cannabis derivate without psychoactive side effects, has also been shown to inhibit the expression of VEGF in Kaposi’s sarcoma cells.[49]

Natalizumab is a monoclonal antibody that was designed to target one of the molecules responsible for cell adhesion (integrin VLA-4) and has promising in vitro activity in B cell lymphomas and leukemias.[44]

Also, Trabectedin is known to have immunomodulatory effects that inhibit TAMs.[30]

Current formulations of liposomes encapsulating anti-cancer drugs for selective uptake to tumors via the EPR effect include: Doxil and Myocet, both of which encapsulate doxorubicin (a DNA intercalator and common chemotherapeutic); DaunoXome, which encapsulates daunorubicin (another DNA intercalator similar to doxorubicin); and Onco-TCS, which encapsulates vincristine (a molecule which constitutively induces formation of microtubules, dysregulating cell division). Another novel utilization of the EPR effect comes from Protein-bound paclitaxel (marketed under the trade name Abraxane) where paclitaxel (a molecule which dysregulates cell division via stabilization of microtubules) is bound to albumin to add bulk and aid delivery.

  1. Michael J. Duffy The biochemistry of metastasis Advances in Clinical Chemistry, Volume 32 1996, Pages 135–160
  2. Fabienne Danhier, Olivier Feron, Véronique Préat To exploit the tumor microenvironment: Passive and active tumor targeting of nanocarriers for anti-cancer drug delivery Journal of Controlled Release, Volume 148, Issue 2, 1 December 2010, Pages 135–146 http://dx.doi.org/10.1016/j.jconrel.2010.08.027
  3. Cynthia E. Weber, Paul C. Kuo The tumor microenvironment Surgical Oncology, Volume 21, Issue 3, September 2012, Pages 172–177 http://dx.doi.org/10.1016/j.suronc.2011.09.001
  4. Mikhail V. Blagosklonny Antiangiogenic therapy and tumor progression Cancer Cell, Volume 5, Issue 1, January 2004, Pages 13–17 http://dx.doi.org/10.1016/S1535-6108(03)00336-2
  5. Ranjit S. Bindra, Peter M. Glazer Genetic instability and the tumor microenvironment: towards the concept of microenvironment-induced mutagenesis Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis, Volume 569, Issues 1–2, 6 January 2005, Pages 75–85 http://dx.doi.org/10.1016/j.mrfmmm.2004.03.013
  6. Robert A. Gatenby & Robert J. Gillies Why do cancers have high aerobic glycolysis? Nature Reviews Cancer Volume 4, November 2004, Pages 891-899 http://dx.doi.org/10.1038/nrc1478
  7. Veronica Estrella, Tingan Chen, Mark Lloyd, Jonathan Wojtkowiak, Heather H. Cornnell, Arig Ibrahim-Hashim, Kate Bailey, Yoganand Balagurunathan, Jennifer M. Rothberg, Bonnie F. Sloane, Joseph Johnson, Robert A. Gatenby, and Robert J. Gillies Acidity Generated by the Tumor Microenvironment Drives Local Invasion Cancer Research, Volume 73, Issue 5, 1 March 2013, Pages 1524-1535 http://dx.doi.org/10.1158/0008-5472.CAN-12-2796
  8. Joydeb Kumar Kundu, Young-Joon Surh Inflammation: Gearing the journey to cancer Mutation Research/Reviews in Mutation Research, Volume 659, Issues 1–2, July–August 2008, Pages 15–30 http://dx.doi.org/10.1016/j.mrrev.2008.03.002
  9. Kati Räsänen, Antti Vaheri Activation of fibroblasts in cancer stroma Experimental Cell Research, Volume 316, Issue 17, 15 October 2010, Pages 2713–2722 http://dx.doi.org/10.1016/j.yexcr.2010.04.032
  10. Timothy Marsh, Kristian Pietras, Sandra S. McAllister Fibroblasts as architects of cancer pathogenesis Biochimica et Biophysica Acta (BBA) – Molecular Basis of Disease Online 30 October 2012http://dx.doi.org/10.1016/j.bbadis.2012.10.013
  11. Michael Quante, Shui Ping Tu, Hiroyuki Tomita, Tamas Gonda, Sophie S.W. Wang, Shigeo Takashi, Gwang Ho Baik, Wataru Shibata, Bethany DiPrete, Kelly S. Betz, Richard Friedman, Andrea Varro, Benjamin Tycko, & Timothy C. Wang Bone Marrow-Derived Myofibroblasts Contribute to the Mesenchymal Stem Cell Niche and Promote Tumor Growth Cancer Cell, Volume 19, Issue 2, 15 February 2011, Pages 257–272 http://dx.doi.org/10.1016/j.ccr.2011.01.02

Pathology Outlines _ Nat Pernick, MD
Copyright: (c) 2002-2015, PathologyOutlines.com, Inc.

Stains
Immunohistochemistry basics

Reviewer: Nat Pernick, M.D. (see Reviewers page)
Revised: 21 March 2014, last major update August 2013
Copyright: (c) 2002-2013, PathologyOutlines.com, Inc.

General
=================================================================

  • Immunohistochemistry (IHC) is a tool for surgical pathology and research
  • Diagnosis should be based on H&E morphology, with confirmation by immunohistochemistry or molecular testing; it is dangerous to use immunohistochemistry alone to make the diagnosis
  • A stain / result is not just positive or negative; focus on the types of cells that are immunoreactive and determine if they are tumor cells, inflammatory cells, normal cells or stromal cells; comparing the results to an H&E stained section or a negative control of the same block may be helpful (Am J Surg Pathol 2007;31:1627J Clin Pathol 2011;64:466)
  • After you identify the type of cell staining, it is helpful to note the percentage of these cells staining, the intensity of staining (weak, 1+, 2+, 3+, 4+) and the pattern of staining (membranous, cytoplasmic, nuclear, dot-like)
  • The pattern of immunoreactivity should follow the anatomic distribution of the antigen before it is called positive / immunoreactive
  • Reference: CAP Laboratory Improvement Programs: Principles of Analytic Validation of Immunohistochemical Assays

Common errors
=================================================================

  • Not using a positive or negative control; they are helpful in interpreting the staining pattern, particularly if it is heavy or weak
  • Other sources of error are ectopic antigen expression (may be due to abundant endogenous biotin, Hum Pathol 2011;42:369), cross reactions (Mod Pathol 2012;25:231), less specificity than thought (Int J Clin Exp Pathol 2012;5:137), use of the wrong secondary antibody (EJN Blog) or rarely the wrong primary antibody

http://www.pathologyoutlines.com/topic/stainsihcbasics.html

Immunohistochemistry – common panels

=========================================================

  • Epithelial markers: low molecular weight keratin (CAM 5.2), AE1-AE3 cytokeratin cocktail, CK7, CK20, CEA and EMA
  • Alternative epithelial markers on sarcomatoid carcinoma include p63, MOC-31 and TTF1 (Mod Pathol 2005;18:1471)
  • Melanocytic markers: S100 (also a mesenchymal marker), HMB45, MelanA / Mart1
  • Lymphoid markers: CD3 (T cells), CD20 (B cells), CD15 (Hodgkin), CD30 (Hodgkin & other) and various others
  • Histiocytic markers: CD68, lysozyme, CD1a (Langerhans cells)
  • Neuroendocrine markers: neuron specific enolase, chromogranin, synaptophysin, CD56 and CD57
  • Mesenchymal markers: vimentin (non-specific), factor XIIIa (fibrous histiocytoma), factor VIII (vessels), CD31 (vessels), CD34 (vessels), D2-40 (lymphatics), HHF35 (actin), smooth muscle actin and desmin
  • Cell proliferation / apoptosis markers: Ki-67, bcl2

http://www.pathologyoutlines.com/topic/stainsihcpanel.html

Tissue of origin / unknown primary

PubMed Search: tissue of origin[title]

=================================================================

IHC stains examples

IHC stains examples

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3380879/bin/onc0061210700003.jpg

CD Markers

=================================================================

CD: cluster designation or cluster of differentiation; a protocol to identify and investigate cell surface molecules

Nomenclature proposed in 1982 at First International Workshop and Conference on Human Leukocyte Differentiation Antigens (HLDA)

A classification system for monoclonal antibodies generated by laboratories worldwide against cell surface molecules, initially on leukocytes, but now also from other cell types

Data is collated and analyzed by cluster analysis based on pattern of binding to leukocytes or other cell types

Must be at least two monoclonal antibodies for each antigen

“w” indicates that the CD is not well characterized or is represented by only one monoclonal antibody

Current CD markers range from CD1 to CD363

Interpretation should be based on cellular distribution of staining (i.e. membranous, cytoplasmic, nuclear), proportion of positively stained cells, staining intensity and cutoff levels

Physiology

=================================================================

CD molecules have various functions, including receptors or ligands; also cell adhesion, antigen presentation

Although commonly used by pathologists to characterize cells, they most likely also have an important (although sometimes unknown) function in cell physiology

http://www.pathologyoutlines.com/topic/cdmarkersgeneral.html

Enzyme cytochemistry

=========================================================================

  • Detects enzymatic activity in cytoplasm
  • Advantage over immunocytochemistry is determination of enzyme’s intracellular localization and intensity of catalytic activity (for research purposes)
  • Flow cytometry and immunocytochemistry are often preferred to determine presence of enzyme molecule (but not catalytic activity or localization)
  • Enzyme product unites with coupler, which produces localized color at site of enzyme activity
  • Fresh smears are preferred, especially for myeloperoxidase; if not possible, store unstained slides away from light

Methods
=================================================================

  • Simultaneous capture: reagent in incubation medium combines with reaction product (example: diazo method for alkaline phosphatase)
  • Post-incubation coupling: insoluble reaction product is coupled with a colored or opaque substance (example: Rutenburg and Seligman method for acid phosphatase)
  • Self-colored substrate reaction: water-soluble dye is made insoluble when enzyme removes a hydrophilic group, leading to colored precipitate at site of enzyme activity
  • Intramolecular rearrangement: produces a colored insoluble precipitate at sites of enzyme activity of an otherwise colorless substrate (University of Iowa)

Molecular Pathology

Authors: Zubair W. Baloch, M.D., Ph.D., Joshua Bradish, M.D., Betty Chung, D.O., M.P.H., M.A., Rodney E. Shackelford, D.O., Ph.D.; Editors: Liang Cheng, M.D., Gregory A. Hosler, M.D., Ph.D. (see Reviewers page)

http://www.pathologyoutlines.com/molecularpath.html

DNA purificationintroductionanalyzing puritybasic protocolanion exchange chromatographycesium chloride density gradient centrifugationcommercial DNA extraction machinesethanol precipitationorganic extractionPCR inhibitorsRNA purificationsilica adsorptiontissue preparation

DNA sequencing: 
historyMaxam-Gilbert sequencingSanger sequencingcapillary electrophoresisother innovationsreal timepyroseqencingnanotechnologyRoche 454 FLX pyrosequencerIllumina Genome AnalyzerHeliScope Sequencer

FISH: 
generalprobesprotocolprobe patternsimages

Microarray: introductionhistorybasicsconsiderationserrors
variations: antibodybead basedcellularCGHsolid phasetissue (TMA)

PCR: 
definitionhistorybasicsTaq polymerasereaction stagesthermocyclersapplications
variations: generalmethylation specificmultiplexnestedreal-timereverse transcriptase  

Nat Pernick and PO group

Nat Pernick and PO group

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Contact us (248/646-0325) with any questions

Pathology Outline

http://www.tumorlibrary.com/outline.jsp

Below is a comprehensive categorization of the diseases documented in this site. Click on a section name, to view the Cases. For many of the diseases we have also provided descriptions in PDF format. To read the disease description, click on the PDF icon next to the disease name.

Diagnosis
A > Z
by Location
by Treatment
by Image Type
Tumor Types
Bone Tumors
Histiocytoses
Pseudotumors
Soft Tissue Tumors

There are some important issues related to the pathology of cancer that need to be addressed. The two references above are both valuable for a source useful for reference to the characterization and methods of identification of most tumors. The second is concerned with soft tissue and bone sarcomas.
PathologyOutlines is also an excellent source for soft tissue and bone sarcomas.

It is important to realize that despite enormous progress in the molecular biology of carcinomas and sarcomas, there is a characteristic natural history and clinical presentation, and the ability to distinguish within types is related to differential expression that is related to metabolic characteristics and tissue differentiation.  The pathologist uses a system of morphological grading based on the nuclear to cytoplasmic ratio, the loss of architecture (such a glandular anaplasia) that is important, but not sufficient.  The staging is based on regional lymph node extension, and to distant metastasis.  In addition, the use of cell differentiation markers and immunohistochemical staining is essential.

However, the field is now being rewritten in a large way that will not have a significant effect for perhaps a decade by the clinical pathology and molecular diagnostics measurement of miRNAs and lncRNAs, that are measureable in tissue and in serum, and the expanded use of mass spectrometry, and MS combined with optical methods. This is important for the differentiation of types of malignant expression within cell types, and will be important for matching malignancy to pharmaceutical targets.  Despite the use of the term cancer targeting, the reality has been that single chemotherapy has not been sufficient in the treatment of advanced disease.  This I attribute to the complexity of the interactions between affected dysregulated pathways. The same problem has been encountered in the multiple hit progression of infection to systemic inflammatory response to sepsis to multiple organ failure. The assumption that there is a magic bullet has been an illusion.  This is where the mathematical modeling has become important because we are dealing with more than one major variable:

  1. Local control
  2. Cell-like cell interactions
  3. Cell-unlike cell interactions
  4. Level of disruption involving cell migration
  5. The level of mitochondrial respiration
  6. The degree of loss of apoptosis

There is also a consideration of age, sex, and endocrine factors.  This is particularly illustrated in the case of childhood malignancies, such as neuroblastoma.  In the case of bone tumors, it is not widely recognized that there is a relationship between muscle and bone in the remodeling process, and a relationship between the type of neoplasm and the anatomical location, and also a relationship to the loss of remodeling control after age 65 years.

This is illustrated by the classification of bone tumors as – periosteal and endosteal, and as epiphyseal, metaphyseal, and diaphyseal (for long bones).
The parosteal sarcoma may be fibrosarcoma or osteosarcoma, and may be derived from a fibrous dysplasia, a myositis ossificans, a fibroxanthoma, a lipoma, or malignant transformation in an osteochondroma.  The prognosis for such a cancer after a local wide excision is far better than a cancer within the bone.  This was the case 40 years ago, long before modern molecular diagnostics.  In the case of epiphyseal lesions, one expects the cancer to be dictated by cartilaginous origin, but it also can arise from a cystic lesion at the joint margin. The growth and development of bone and the greatest activity of growth in length of a long bone is at the growth plate, in the metaphysis.  This also happens to be the site most affected by scurvy, rickets (articular cartilage and metaphysis), and by hyperparathyroidism. The metaphysis is where the cartilage is converted to calcified bone matrix, which is remodeled by the removal of bone by osteoblasts and the laying down of bone by osteoblasts.  Stable bone at equilibrium is maintained by osteocytes.  The circulation in bone is in Volkmann’s canals.  What types of tumors do we find at the metaphysis? Malignant Giant Cell Tumor and Osteosarcoma.  Chondrosarcomas may arise there also from an enchondroma, a benign tumor within the bone at the metaphysis, or an osteochondroma.  Perhaps the most wild type of bone tumor is the malignant combined giant cell and osteogenic sarcoma that arises in Paget’s disease.  This is a disease that occurs in older age which is characterized by a loss of control of bone remodeling resulting in the rapid remodeling of bone with the generation of a primitive bone that can be called – pumice bone. It is easily fractured.  Bone remodels to a peak in the late 30’s, and then slows down, but occurs throughout life. The bone becomes more compact.  In remodeling bone is removed by osteoclasts and bone is added by osteoblasts.  A single osteoclast removes 100 microns of bone that is replaced by 100 osteoblasts adding 1 micron each.  This dynamic was measured by Dr. Lent C. Johnson.

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