Archive for the ‘Metastasis Process’ Category

Renal tumor macrophages linked to recurrence are identified using single-cell protein activity analysis

Curator and Reporter: Dr. Premalata Pati, Ph.D., Postdoc

When malignancy returns after a period of remission, it is called a cancer recurrence. After the initial or primary cancer has been treated, this can happen weeks, months, or even years later. The possibility of recurrence is determined by the type of primary cancer. Because small patches of cancer cells might stay in the body after treatment, cancer might reoccur. These cells may multiply and develop large enough to cause symptoms or cause cancer over time. The type of cancer determines when and where cancer recurs. Some malignancies have a predictable recurrence pattern.

Even if primary cancer recurs in a different place of the body, recurrent cancer is designated for the area where it first appeared. If breast cancer recurs distantly in the liver, for example, it is still referred to as breast cancer rather than liver cancer. It’s referred to as metastatic breast cancer by doctors. Despite treatment, many people with kidney cancer eventually develop cancer recurrence and incurable metastatic illness.

The most frequent type of kidney cancer is Renal Cell Carcinoma (RCC). RCC is responsible for over 90% of all kidney malignancies. The appearance of cancer cells when viewed under a microscope helps to recognize the various forms of RCC. Knowing the RCC subtype can help the doctor assess if the cancer is caused by an inherited genetic condition and help to choose the best treatment option. The three most prevalent RCC subtypes are as follows:

  • Clear cell RCC
  • Papillary RCC
  • Chromophobe RCC

Clear Cell RCC (ccRCC) is the most prevalent subtype of RCC. The cells are clear or pale in appearance and are referred to as the clear cell or conventional RCC. Around 70% of people with renal cell cancer have ccRCC. The rate of growth of these cells might be sluggish or rapid. According to the American Society of Clinical Oncology (ASCO), clear cell RCC responds favorably to treatments like immunotherapy and treatments that target specific proteins or genes.

Researchers at Columbia University’s Vagelos College of Physicians and Surgeons have developed a novel method for identifying which patients are most likely to have cancer relapse following surgery.

The study

Their findings are detailed in a study published in the journal Cell entitled, “Single-Cell Protein Activity Analysis Identifies Recurrence-Associated Renal Tumor Macrophages.” The researchers show that the presence of a previously unknown type of immune cell in kidney tumors can predict who will have cancer recurrence.

According to co-senior author Charles Drake, MD, PhD, adjunct professor of medicine at Columbia University Vagelos College of Physicians and Surgeons and the Herbert Irving Comprehensive Cancer Center,

the findings imply that the existence of these cells could be used to identify individuals at high risk of disease recurrence following surgery who may be candidates for more aggressive therapy.

As Aleksandar Obradovic, an MD/PhD student at Columbia University Vagelos College of Physicians and Surgeons and the study’s co-first author, put it,

it’s like looking down over Manhattan and seeing that enormous numbers of people from all over travel into the city every morning. We need deeper details to understand how these different commuters engage with Manhattan residents: who are they, what do they enjoy, where do they go, and what are they doing?

To learn more about the immune cells that invade kidney cancers, the researchers employed single-cell RNA sequencing. Obradovic remarked,

In many investigations, single-cell RNA sequencing misses up to 90% of gene activity, a phenomenon known as gene dropout.

The researchers next tackled gene dropout by designing a prediction algorithm that can identify which genes are active based on the expression of other genes in the same family. “Even when a lot of data is absent owing to dropout, we have enough evidence to estimate the activity of the upstream regulator gene,” Obradovic explained. “It’s like when playing ‘Wheel of Fortune,’ because I can generally figure out what’s on the board even if most of the letters are missing.”

The meta-VIPER algorithm is based on the VIPER algorithm, which was developed in Andrea Califano’s group. Califano is the head of Herbert Irving Comprehensive Cancer Center’s JP Sulzberger Columbia Genome Center and the Clyde and Helen Wu professor of chemistry and systems biology. The researchers believe that by including meta-VIPER, they will be able to reliably detect the activity of 70% to 80% of all regulatory genes in each cell, eliminating cell-to-cell dropout.

Using these two methods, the researchers were able to examine 200,000 tumor cells and normal cells in surrounding tissues from eleven patients with ccRCC who underwent surgery at Columbia’s urology department.

The researchers discovered a unique subpopulation of immune cells that can only be found in tumors and is linked to disease relapse after initial treatment. The top genes that control the activity of these immune cells were discovered through the VIPER analysis. This “signature” was validated in the second set of patient data obtained through a collaboration with Vanderbilt University researchers; in this second set of over 150 patients, the signature strongly predicted recurrence.

These findings raise the intriguing possibility that these macrophages are not only markers of more risky disease, but may also be responsible for the disease’s recurrence and progression,” Obradovic said, adding that targeting these cells could improve clinical outcomes

Drake said,

Our research shows that when the two techniques are combined, they are extremely effective at characterizing cells within a tumor and in surrounding tissues, and they should have a wide range of applications, even beyond cancer research.

Main Source

Single-cell protein activity analysis identifies recurrence-associated renal tumor macrophages


Other Related Articles published in this Open Access Online Scientific Journal include the following:

Machine Learning (ML) in cancer prognosis prediction helps the researcher to identify multiple known as well as candidate cancer diver genes

Curator and Reporter: Dr. Premalata Pati, Ph.D., Postdoc


Renal (Kidney) Cancer: Connections in Metabolism at Krebs cycle  and Histone Modulation

Curator: Demet Sag, PhD, CRA, GCP


Artificial Intelligence: Genomics & Cancer


Bioinformatic Tools for Cancer Mutational Analysis: COSMIC and Beyond

Curator: Stephen J. Williams, Ph.D.


Deep-learning AI algorithm shines new light on mutations in once obscure areas of the genome

Reporter: Aviva Lev-Ari, PhD, RN


Premalata Pati, PhD, PostDoc in Biological Sciences, Medical Text Analysis with Machine Learning


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Inhibitory CD161 receptor recognized as a potential immunotherapy target in glioma-infiltrating T cells by single-cell analysis

Reporter: Dr. Premalata Pati, Ph.D., Postdoc


Brain tumors, especially the diffused Gliomas are of the most devastating forms of cancer and have so-far been resistant to immunotherapy. It is comprehended that T cells can penetrate the glioma cells, but it still remains unknown why infiltrating cells miscarry to mount a resistant reaction or stop the tumor development.

Gliomas are brain tumors that begin from neuroglial begetter cells. The conventional therapeutic methods including, surgery, chemotherapy, and radiotherapy, have accomplished restricted changes inside glioma patients. Immunotherapy, a compliance in cancer treatment, has introduced a promising strategy with the capacity to penetrate the blood-brain barrier. This has been recognized since the spearheading revelation of lymphatics within the central nervous system. Glioma is not generally carcinogenic. As observed in a number of cases, the tumor cells viably reproduce and assault the adjoining tissues, by and large, gliomas are malignant in nature and tend to metastasize. There are four grades in glioma, and each grade has distinctive cell features and different treatment strategies. Glioblastoma is a grade IV glioma, which is the crucial aggravated form. This infers that all glioblastomas are gliomas, however, not all gliomas are glioblastomas.

Decades of investigations on infiltrating gliomas still take off vital questions with respect to the etiology, cellular lineage, and function of various cell types inside glial malignancies. In spite of the available treatment options such as surgical resection, radiotherapy, and chemotherapy, the average survival rate for high-grade glioma patients remains 1–3 years (1).

A recent in vitro study performed by the researchers of Dana-Farber Cancer Institute, Massachusetts General Hospital, and the Broad Institute of MIT and Harvard, USA, has recognized that CD161 is identified as a potential new target for immunotherapy of malignant brain tumors. The scientific team depicted their work in the Cell Journal, in a paper entitled, “Inhibitory CD161 receptor recognized in glioma-infiltrating T cells by single-cell analysis.” on 15th February 2021.

To further expand their research and findings, Dr. Kai Wucherpfennig, MD, PhD, Chief of the Center for Cancer Immunotherapy, at Dana-Farber stated that their research is additionally important in a number of other major human cancer types such as 

  • melanoma,
  • lung,
  • colon, and
  • liver cancer.

Dr. Wucherpfennig has praised the other authors of the report Mario Suva, MD, PhD, of Massachusetts Common Clinic; Aviv Regev, PhD, of the Klarman Cell Observatory at Broad Institute of MIT and Harvard, and David Reardon, MD, clinical executive of the Center for Neuro-Oncology at Dana-Farber.

Hence, this new study elaborates the effectiveness of the potential effectors of anti-tumor immunity in subsets of T cells that co-express cytotoxic programs and several natural killer (NK) cell genes.

The Study-

IMAGE SOURCE: Experimental Strategy (Mathewson et al., 2021)


The group utilized single-cell RNA sequencing (RNA-seq) to mull over gene expression and the clonal picture of tumor-infiltrating T cells. It involved the participation of 31 patients suffering from diffused gliomas and glioblastoma. Their work illustrated that the ligand molecule CLEC2D activates CD161, which is an immune cell surface receptor that restrains the development of cancer combating activity of immune T cells and tumor cells in the brain. The study reveals that the activation of CD161 weakens the T cell response against tumor cells.

Based on the study, the facts suggest that the analysis of clonally expanded tumor-infiltrating T cells further identifies the NK gene KLRB1 that codes for CD161 as a candidate inhibitory receptor. This was followed by the use of 

  • CRISPR/Cas9 gene-editing technology to inactivate the KLRB1 gene in T cells and showed that CD161 inhibits the tumor cell-killing function of T cells. Accordingly,
  • genetic inactivation of KLRB1 or
  • antibody-mediated CD161 blockade

enhances T cell-mediated killing of glioma cells in vitro and their anti-tumor function in vivo. KLRB1 and its associated transcriptional program are also expressed by substantial T cell populations in other forms of human cancers. The work provides an atlas of T cells in gliomas and highlights CD161 and other NK cell receptors as immune checkpoint targets.

Further, it has been identified that many cancer patients are being treated with immunotherapy drugs that disable their “immune checkpoints” and their molecular brakes are exploited by the cancer cells to suppress the body’s defensive response induced by T cells against tumors. Disabling these checkpoints lead the immune system to attack the cancer cells. One of the most frequently targeted checkpoints is PD-1. However, recent trials of drugs that target PD-1 in glioblastomas have failed to benefit the patients.

In the current study, the researchers found that fewer T cells from gliomas contained PD-1 than CD161. As a result, they said, “CD161 may represent an attractive target, as it is a cell surface molecule expressed by both CD8 and CD4 T cell subsets [the two types of T cells engaged in response against tumor cells] and a larger fraction of T cells express CD161 than the PD-1 protein.”

However, potential side effects of antibody-mediated blockade of the CLEC2D-CD161 pathway remain unknown and will need to be examined in a non-human primate model. The group hopes to use this finding in their future work by

utilizing their outline by expression of KLRB1 gene in tumor-infiltrating T cells in diffuse gliomas to make a remarkable contribution in therapeutics related to immunosuppression in brain tumors along with four other common human cancers ( Viz. melanoma, non-small cell lung cancer (NSCLC), hepatocellular carcinoma, and colorectal cancer) and how this may be manipulated for prevalent survival of the patients.


(1) Anders I. Persson, QiWen Fan, Joanna J. Phillips, William A. Weiss, 39 – Glioma, Editor(s): Sid Gilman, Neurobiology of Disease, Academic Press, 2007, Pages 433-444, ISBN 9780120885923, https://doi.org/10.1016/B978-012088592-3/50041-4.

Main Source

Mathewson ND, Ashenberg O, Tirosh I, Gritsch S, Perez EM, Marx S, et al. 2021. Inhibitory CD161 receptor identified in glioma-infiltrating T cells by single-cell analysis. Cell.https://www.cell.com/cell/fulltext/S0092-8674(21)00065-9?elqTrackId=c3dd8ff1d51f4aea87edd0153b4f2dc7

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19th Annual Koch Institute Summer Symposium on Cancer Immunotherapy, June 12, 2020 at MIT’s Kresge Auditorium


Other related articles published in this Open Access Online Scientific Journal include the following:


Single Cell Sequencing:

Part 4.1 in Genomics Volume 2

Latest in Genomics Methodologies for Therapeutics: Gene Editing, NGS & BioInformatics, Simulations and the Genome Ontology 

On Amazon.com since 12/28/2019



4.1.3   Single-cell Genomics: Directions in Computational and Systems Biology – Contributions of Prof. Aviv Regev @Broad Institute of MIT and Harvard, Cochair, the Human Cell Atlas Organizing Committee with Sarah Teichmann of the Wellcome Trust Sanger Institute

Curator: Aviva Lev-Ari, PhD, RN



4.1.4   Cellular Genetics



4.1.5   Cellular Genomics



4.1.6   SINGLE CELL GENOMICS 2019 – sometimes the sum of the parts is greater than the whole, September 24-26, 2019, Djurönäset, Stockholm, Sweden http://www.weizmann.ac.il/conferences/SCG2019/single-cell-genomics-2019

Reporter: Aviva Lev-Ari, PhD, RN



4.1.7   Norwich Single-Cell Symposium 2019, Earlham Institute, single-cell genomics technologies and their application in microbial, plant, animal and human health and disease, October 16-17, 2019, 10AM-5PM

Reporter: Aviva Lev-Ari, PhD, RN



4.1.8   Newly Found Functions of B Cell

Reporter and Curator: Dr. Sudipta Saha, Ph.D.






CRISPR – 200 articles in the Journal


Chapter 21 in Genomics Volume 1

Genomics Orientations for Personalized Medicine. On Amazon.com since 11/23/2015



Glioblastoma – 150 articles in the Journal

Most recent


Immunotherapy may help in glioblastoma survival

Reporter and Curator: Dr. Sudipta Saha, Ph.D.



New Treatment in Development for Glioblastoma: Hopes for Sen. John McCain

Reporter: Aviva Lev-Ari, PhD, RN



Funding Oncorus’s Immunotherapy Platform: Next-generation Oncolytic Herpes Simplex Virus (oHSV) for Brain Cancer, Glioblastoma Multiforme (GBM)

Reporter: Aviva Lev-Ari, PhD, RN



Glioma, Glioblastoma and Neurooncology

Curator: Larry H. Bernstein, MD, FCAP



Positron Emission Tomography (PET) and Near-Infrared Fluorescence Imaging:  Noninvasive Imaging of Cancer Stem Cells (CSCs)  monitoring of AC133+ glioblastoma in subcutaneous and intracerebral xenograft tumors

Reporter: Aviva Lev-Ari, PhD, RN



Gamma Linolenic Acid (GLA) as a Therapeutic tool in the Management of Glioblastoma

Eric Fine* (1), Mike Briggs* (1,2), Raphael Nir# (1,2,3)




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Immunotherapy may help in glioblastoma survival

Immunotherapy may help in glioblastoma survival, Volume 2 (Volume Two: Latest in Genomics Methodologies for Therapeutics: Gene Editing, NGS and BioInformatics, Simulations and the Genome Ontology), Part 1: Next Generation Sequencing (NGS)

Reporter and Curator: Dr. Sudipta Saha, Ph.D.


Glioblastoma is the most common primary malignant brain tumor in adults and is associated with poor survival. But, in a glimmer of hope, a recent study found that a drug designed to unleash the immune system helped some patients live longer. Glioblastoma powerfully suppresses the immune system, both at the site of the cancer and throughout the body, which has made it difficult to find effective treatments. Such tumors are complex and differ widely in their behavior and characteristics.


A small randomized, multi-institution clinical trial was conducted and led by researchers at the University of California at Los Angeles involved patients who had a recurrence of glioblastoma, the most common central nervous system cancer. The aim was to evaluate immune responses and survival following neoadjuvant and/or adjuvant therapy with pembrolizumab (checkpoint inhibitor) in 35 patients with recurrent, surgically resectable glioblastoma. Patients who were randomized to receive neoadjuvant pembrolizumab, with continued adjuvant therapy following surgery, had significantly extended overall survival compared to patients that were randomized to receive adjuvant, post-surgical programmed cell death protein 1 (PD-1) blockade alone.


Neoadjuvant PD-1 blockade was associated with upregulation of T cell– and interferon-γ-related gene expression, but downregulation of cell-cycle-related gene expression within the tumor, which was not seen in patients that received adjuvant therapy alone. Focal induction of programmed death-ligand 1 in the tumor microenvironment, enhanced clonal expansion of T cells, decreased PD-1 expression on peripheral blood T cells and a decreasing monocytic population was observed more frequently in the neoadjuvant group than in patients treated only in the adjuvant setting. These findings suggest that the neoadjuvant administration of PD-1 blockade enhanced both the local and systemic antitumor immune response and may represent a more efficacious approach to the treatment of this uniformly lethal brain tumor.


Immunotherapy has not proved to be effective against glioblastoma. This small clinical trial explored the effect of PD-1 blockade on recurrent glioblastoma in relation to the timing of administration. A total of 35 patients undergoing resection of recurrent disease were randomized to either neoadjuvant or adjuvant pembrolizumab, and surgical specimens were compared between the two groups. Interestingly, the tumoral gene expression signature varied between the two groups, such that those who received neoadjuvant pembrolizumab displayed an INF-γ gene signature suggestive of T-cell activation as well as suppression of cell-cycle signaling, possibly consistent with growth arrest. Although the study was not powered for efficacy, the group found an increase in overall survival in patients receiving neoadjuvant pembrolizumab compared with adjuvant pembrolizumab of 13.7 months versus 7.5 months, respectively.


In this small pilot study, neoadjuvant PD-1 blockade followed by surgical resection was associated with intratumoral T-cell activation and inhibition of tumor growth as well as longer survival. How the drug works in glioblastoma has not been totally established. The researchers speculated that giving the drug before surgery prompted T-cells within the tumor, which had been impaired, to attack the cancer and extend lives. The drug didn’t spur such anti-cancer activity after the surgery because those T-cells were removed along with the tumor. The results are very important and very promising but would need to be validated in much larger trials.














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Lesson 5 Cell Signaling And Motility: Cytoskeleton & Actin: Curations and Articles of reference as supplemental information: #TUBiol3373

Curator: Stephen J. Williams, Ph.D.

Cell motility or migration is an essential cellular process for a variety of biological events. In embryonic development, cells migrate to appropriate locations for the morphogenesis of tissues and organs. Cells need to migrate to heal the wound in repairing damaged tissue. Vascular endothelial cells (ECs) migrate to form new capillaries during angiogenesis. White blood cells migrate to the sites of inflammation to kill bacteria. Cancer cell metastasis involves their migration through the blood vessel wall to invade surrounding tissues.

Please Click on the Following Powerpoint Presentation for Lesson 4 on the Cytoskeleton, Actin, and Filaments


cell signaling 5 lesson

This post will be updated with further information when we get into Lesson 6 and complete our discussion on the Cytoskeleton

Please see the following articles on Actin and the Cytoskeleton in Cellular Signaling

Role of Calcium, the Actin Skeleton, and Lipid Structures in Signaling and Cell Motility

This article, constitutes a broad, but not complete review of the emerging discoveries of the critical role of calcium signaling on cell motility and, by extension, embryonic development, cancer metastasis, changes in vascular compliance at the junction between the endothelium and the underlying interstitial layer.  The effect of calcium signaling on the heart in arrhtmogenesis and heart failure will be a third in this series, while the binding of calcium to troponin C in the synchronous contraction of the myocardium had been discussed by Dr. Lev-Ari in Part I.

Universal MOTIFs essential to skeletal muscle, smooth muscle, cardiac syncytial muscle, endothelium, neovascularization, atherosclerosis and hypertension, cell division, embryogenesis, and cancer metastasis. The discussion will be presented in several parts:
1.  Biochemical and signaling cascades in cell motility
2.  Extracellular matrix and cell-ECM adhesions
3.  Actin dynamics in cell-cell adhesion
4.  Effect of intracellular Ca++ action on cell motility
5.  Regulation of the cytoskeleton
6.  Role of thymosin in actin-sequestration
7.  T-lymphocyte signaling and the actin cytoskeleton


Identification of Biomarkers that are Related to the Actin Cytoskeleton

In this article the Dr. Larry Bernstein covers two types of biomarker on the function of actin in cytoskeleton mobility in situ.

  • First, is an application in developing the actin or other component, for a biotarget and then, to be able to follow it as

(a) a biomarker either for diagnosis, or

(b) for the potential treatment prediction of disease free survival.

  • Second, is mostly in the context of MI, for which there is an abundance of work to reference, and a substantial body of knowledge about

(a) treatment and long term effects of diet, exercise, and

(b) underlying effects of therapeutic drugs.

Microtubule-Associated Protein Assembled on Polymerized Microtubules

(This article has a great 3D visualization of a microtuble structure as well as description of genetic diseases which result from mutations in tubulin and effects on intracellular trafficking of proteins.

A latticework of tiny tubes called microtubules gives your cells their shape and also acts like a railroad track that essential proteins travel on. But if there is a glitch in the connection between train and track, diseases can occur. In the November 24, 2015 issue of PNAS, Tatyana Polenova, Ph.D., Professor of Chemistry and Biochemistry, and her team at the University of Delaware (UD), together with John C. Williams, Ph.D., Associate Professor at the Beckman Research Institute of City of Hope in Duarte, California, reveal for the first time — atom by atom — the structure of a protein bound to a microtubule. The protein of focus, CAP-Gly, short for “cytoskeleton-associated protein-glycine-rich domains,” is a component of dynactin, which binds with the motor protein dynein to move cargoes of essential proteins along the microtubule tracks. Mutations in CAP-Gly have been linked to such neurological diseases and disorders as Perry syndrome and distal spinal bulbar muscular dystrophy.


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The Puzzle of Stem Cells and Cancer Stem Cells: The MIT Stem Cell Initiative

Reporter: Irina Robu, PhD

The MIT Stem Cell Initiative is looking to research fundamental biological questions about normal adult stem cells and their malignant counterparts, cancer stem cells. The MIT Stem Cell Initiative is applying new technologies and approaches in pursuit of this goal. In particular, the MIT Stem Cell Initiative has focused on the breast and colon, as these tissues are quite different from each other, yet each constitutes a major portion of cancer occurrence. The program purposes are to

(a) identify the stem cells and cancer stem cells in various tissues and tumor types,

(b) control how these cells change during aging or with disease progression and

(c) determine the similarities and differences between

  • normal cells, and
  • cancer stem cells,

with the goal of finding weaknesses in cancer stem cells that can be feasible and exact targets for treatment.

In due course, the ability to identify, purify, and establish several populations of stem cells and cancer stem cells could aid researchers to understand the biology of these cells, and learn how to exploit them more efficiently in regenerative medicine applications and target them in cancer.

Normal adult stem cells are undifferentiated cells within a tissue that divide to produce two daughter cells and divide periodically to replenish or repair the tissue. One of the two daughter cells remain in the stem cell state and the other adopts a partially differentiated state, then goes on to divide and differentiate further to harvest multiple cell types that form that tissue. The division process is through a precise process to ensure that tissues are restricted to the appropriate size and cell content.

Cancer stem cells perform the same division but, rather than differentiating, the additional cells produced by the second daughter cell amass to form the bulk of the tumor.

  • Cancer stem cells can regrow the tumor, and
  • are frequently resistant to chemotherapy.

This exclusive ability of normal and cancer stem cells to both self-renew and form a tissue or tumor is referred to by researchers as “stemness,” and has important implications for biomedical applications.

As a result, cancer stem cells are thought to be responsible for

  • tumor recurrence after remission, and also for the
  • formation of metastases, which account for the majority of cancer-associated deaths.

Accordingly, an anti-cancer stem cell therapy that can target and kill cancer stem cells is one of the holy grail of cancer treatment as means to suppress both tumor recurrence and metastatic disease. One of the important tasks to studying normal and cancer stem cells, and to ultimately harnessing that knowledge is developing the ability to identify, purify, and propagate these cells. Accordingly, the main goal in stem cell and cancer stem cell research is discovering ways to distinguish them, preferably by identifying unique surface markers that can be used to cleanse stem cell and cancer stem cell populations and enable their study.

New technologies are permitting the researchers to make significant headway in these investigations, progress that was not possible just a few years ago. Explicitly, they are using

  • a mixture of specially cultured cells,
  • highly controllable mouse models of cancer, and s
  • ingle-cell RNA sequencing and
  • computational analysis techniques that are extremely matched to extracting an excessive deal of information from the moderately small number of stem cells.



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Knowing the genetic vulnerability of bladder cancer for therapeutic intervention, Volume 2 (Volume Two: Latest in Genomics Methodologies for Therapeutics: Gene Editing, NGS and BioInformatics, Simulations and the Genome Ontology), Part 1: Next Generation Sequencing (NGS)

Knowing the genetic vulnerability of bladder cancer for therapeutic intervention

Reporter and Curator: Dr. Sudipta Saha, Ph.D.


A mutated gene called RAS gives rise to a signalling protein Ral which is involved in tumour growth in the bladder. Many researchers tried and failed to target and stop this wayward gene. Signalling proteins such as Ral usually shift between active and inactive states.


So, researchers next tried to stop Ral to get into active state. In inacvtive state Ral exposes a pocket which gets closed when active. After five years, the researchers found a small molecule dubbed BQU57 that can wedge itself into the pocket to prevent Ral from closing and becoming active. Now, BQU57 has been licensed for further development.


Researchers have a growing genetic data on bladder cancer, some of which threaten to overturn the supposed causes of bladder cancer. Genetics has also allowed bladder cancer to be reclassified from two categories into five distinct subtypes, each with different characteristics and weak spots. All these advances bode well for drug development and for improved diagnosis and prognosis.


Among the groups studying the genetics of bladder cancer are two large international teams: Uromol (named for urology and molecular biology), which is based at Aarhus University Hospital in Denmark, and The Cancer Genome Atlas (TCGA), based at institutions in Texas and Boston. Each team tackled a different type of cancer, based on the traditional classification of whether or not a tumour has grown into the muscle wall of the bladder. Uromol worked on the more common, earlier form, non-muscle-invasive bladder cancer, whereas TCGA is looking at muscle-invasive bladder cancer, which has a lower survival rate.


The Uromol team sought to identify people whose non-invasive tumours might return after treatment, becoming invasive or even metastatic. Bladder cancer has a high risk of recurrence, so people whose non-invasive cancer has been treated need to be monitored for many years, undergoing cystoscopy every few months. They looked for predictive genetic footprints in the transcriptome of the cancer, which contains all of a cell’s RNA and can tell researchers which genes are turned on or off.


They found three subgroups with distinct basal and luminal features, as proposed by other groups, each with different clinical outcomes in early-stage bladder cancer. These features sort bladder cancer into genetic categories that can help predict whether the cancer will return. The researchers also identified mutations that are linked to tumour progression. Mutations in the so-called APOBEC genes, which code for enzymes that modify RNA or DNA molecules. This effect could lead to cancer and cause it to be aggressive.


The second major research group, TCGA, led by the National Cancer Institute and the National Human Genome Research Institute, that involves thousands of researchers across USA. The project has already mapped genomic changes in 33 cancer types, including breast, skin and lung cancers. The TCGA researchers, who study muscle-invasive bladder cancer, have looked at tumours that were already identified as fast-growing and invasive.


The work by Uromol, TCGA and other labs has provided a clearer view of the genetic landscape of early- and late-stage bladder cancer. There are five subtypes for the muscle-invasive form: luminal, luminal–papillary, luminal–infiltrated, basal–squamous, and neuronal, each of which is genetically distinct and might require different therapeutic approaches.


Bladder cancer has the third-highest mutation rate of any cancer, behind only lung cancer and melanoma. The TCGA team has confirmed Uromol research showing that most bladder-cancer mutations occur in the APOBEC genes. It is not yet clear why APOBEC mutations are so common in bladder cancer, but studies of the mutations have yielded one startling implication. The APOBEC enzyme causes mutations early during the development of bladder cancer, and independent of cigarette smoke or other known exposures.


The TCGA researchers found a subset of bladder-cancer patients, those with the greatest number of APOBEC mutations, had an extremely high five-year survival rate of about 75%. Other patients with fewer APOBEC mutations fared less well which is pretty surprising.


This detailed knowledge of bladder-cancer genetics may help to pinpoint the specific vulnerabilities of cancer cells in different people. Over the past decade, Broad Institute researchers have identified more than 760 genes that cancer needs to grow and survive. Their genetic map might take another ten years to finish, but it will list every genetic vulnerability that can be exploited. The goal of cancer precision medicine is to take the patient’s tumour and decode the genetics, so the clinician can make a decision based on that information.
















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Pioneers of Cancer Cell Therapy:  Turbocharging the Immune System to Battle Cancer Cells — Success in Hematological Cancers vs. Solid Tumors

Curator: Aviva Lev-Ari, PhD, RN

Chimeric Antigen Receptor T-Cell Therapy: Players in Basic & Translational Research and Biotech/Pharma

The companies are teamed with academic pioneers:

  • Novartis with University of Pennsylvania;
  • Kite Pharma with the National Cancer Institute; 
  • Juno Therapeutics with Sloan Kettering,
  • the Fred Hutchinson Cancer Research Center in Seattle and Seattle Children’s Hospital.

IMAGE SOURCE: National Cancer Institute

 “CAR-T cell immunotherapy” –  genetically modified T cells that are engineered to target specific tumor antigens and/or genes that are involved in survival, proliferation, and the enhancement of effector functions have been under intense research.

CAR technology was originally reported by Zelig Eshhar in 1993.


Prof. Zelig Eshhar, Ph.D., served as Chairman of the Department of Immunology at the Weizmann Institute. Prof. Eshhar has been Chair of Scientific Advisory Board at TxCell S.A. since April 2016. Prof. Eshhar has been a Member of Scientific Advisory Board at Kite Pharma, Inc. since August 8, 2013. Prof. Eshhar served as a Member of Scientific Advisory Board at Intellect Neurosciences, Inc. since April 2006.

Prof. Eshhar pioneered the CAR approach (or T-Body as he termed it) to redirect T cells to recognize, engage and kill patient’s tumor cells by engineering them with a construct that combines the anti-target specificity of an antibody with T cell activation domains. Prof. Eshhar serves on several editorial boards, including Cancer Gene Therapy, Human Gene Therapy, Gene Therapy, Expert Opinion on Therapeutics, European Journal of Immunology and the Journal of Gene Medicine. He was a Research Fellow in the Department of Pathology at Harvard Medical School and in the Department of Chemical Immunology at the Weizmann Institute in Israel. His achievements were recognized by several international awards, most recently the CAR Pioneering award by the ATTACK European Consortium. Prof. Eshhar obtained his B.Sc. in Biochemistry and Microbiology and his M.Sc. in Biochemistry from the Hebrew University, and his Ph.D. in the Department of Immunology from the Weizmann Institute of Science.


Zelig Eshhar and Carl H. June honored for research on T cell engineering for cancer immunotherapy


New Rochelle, NY, November 11, 2014–Zelig Eshhar, PhD, The Weizmann Institute of Science and Sourasky Medical Center, and Carl H. June, MD, PhD, Perelman School of Medicine, University of Pennsylvania, are co-recipients of the Pioneer Award, recognized for lentiviral gene therapy clinical trials and for their leadership and contributions in engineering T-cells capable of targeting tumors with antibody-like specificity through the development of chimeric antigen receptors (CARs). Human Gene Therapy, a peer-reviewed journal from Mary Ann Liebert, Inc., publishers, is commemorating its 25th anniversary by bestowing this honor on the leading Pioneers in the field of cell and gene therapy selected by a blue ribbon panel* and publishing a Pioneer Perspective by the award recipients. The Perspectives by Dr. Eshhar and Dr. June are available free on the Human Gene Therapy website at http://www.liebertpub.com/hgt until December 11, 2014.

In his Pioneer Perspective entitled “From the Mouse Cage to Human Therapy: A Personal Perspective of the Emergence of T-bodies/Chimeric Antigen Receptor T Cells” Professor Eshhar chronicles his team’s groundbreaking contributions to the development of the CAR T-cell immunotherapeutic approach to treating cancer. He describes the method’s conceptual development including initial proof-of-concept, and the years of experimentation in mouse models of cancer. They first tested the CAR T-cells on tumors transplanted into mice then progressed to spontaneously developing cancers in immune-competent mice, which Dr. Eshhar describes as “a more suitable model that faithfully mimics cancer patients.” He recounts successful antitumor effects in mice with CAR modified T-cells injected directly into tumors, with effects seen at the injection site and at sites of metastasis, and even the potential of the CAR T-cells to prevent tumor development.

Dr. Carl H. June has led one of the clinical groups that has taken the CAR therapeutic strategy from the laboratory to the patients’ bedside, pioneering the use of CD19-specific CAR T-cells to treat patients with leukemia. In his Pioneer Perspective, “Toward Synthetic Biology with Engineered T Cells: A Long Journey Just Begun” Dr. June looks back on his long, multi-faceted career and describes how he combined his knowledge and research on immunology, cancer, and HIV to develop successful T-cell based immunotherapies. Among the lessons Dr. June has embraced throughout his career are to follow one’s passions. He also says that “accidents can be good: embrace the unexpected results and follow up on these as they are often times more scientifically interesting than predictable responses from less imaginative experiments.”

“These two extraordinary scientists made seminal contributions at key steps of the journey from bench to bedside for CAR T-cells,” says James M. Wilson, MD, PhD, Editor-in-Chief of Human Gene Therapy, and Director of the Gene Therapy Program, Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia.




The General procedure of CAR-T cell therapy involves the follwoing steps:

1) Separate T cells from patient;

2) Engineer these T cells to express an artificial receptor, which is called “CAR” that usually targets tumor-specific antigen;

3) Expand the CAR T cells to a sufficient amount;

4) Re-introduce the CAR T cells to patient.

There are two major components that are critical to the CAR-T cell immunotherapy:

  • the design of CAR itself and
  • the choice of the targeted tumor specific antigen.



First publication on Adoptive transfer of genetically modified T cells is an attractive approach for generating antitumor immune responses

Eradication of B-lineage cells and regression of lymphoma in a patient treated with autologous T cells genetically engineered to recognize CD19

James N. Kochenderfer, Wyndham H. Wilson, John E. Janik, Mark E. Dudley, Maryalice Stetler-Stevenson, Steven A. Feldman, Irina Maric, Mark Raffeld, Debbie-Ann N. Nathan, Brock J. Lanier, Richard A. Morgan, Steven A. Rosenberg


Adoptive transfer of genetically modified T cells is an attractive approach for generating antitumor immune responses. We treated a patient with advanced follicular lymphoma by administering a preparative chemotherapy regimen followed by autologous T cells genetically engineered to express a chimeric antigen receptor (CAR) that recognized the B-cell antigen CD19. The patient’s lymphoma underwent a dramatic regression, and B-cell precursors were selectively eliminated from the patient’s bone marrow after infusion of anti–CD19-CAR-transduced T cells. Blood B cells were absent for at least 39 weeks after anti–CD19-CAR-transduced T-cell infusion despite prompt recovery of other blood cell counts. Consistent with eradication of B-lineage cells, serum immunoglobulins decreased to very low levels after treatment. The prolonged and selective elimination of B-lineage cells could not be attributed to the chemotherapy that the patient received and indicated antigen-specific eradication of B-lineage cells. Adoptive transfer of anti–CD19-CAR-expressing T cells is a promising new approach for treating B-cell malignancies. This study is registered at www.clinicaltrials.gov as #NCT00924326.


According to Setting the Body’s ‘Serial Killers’ Loose on Cancer

After a long, intense pursuit, researchers are close to bringing to market a daring new treatment: cell therapy that turbocharges the immune system to fight cancer.



Dr. June’s 2011 publications did not cite Dr. Rosenberg’s paper [Blood, 2010] from the previous year, prompting Dr. Rosenberg to write a letter to The New England Journal of Medicine. Dr. June’s publications also did not acknowledge that the genetic construct he had used was the one he had obtained from Dr. Campana of St. Jude.

From the Lab to the bedside to the Out Patient Clinic

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Astrogliosis and Neuroinflammation: The Metastesis Process form Skin Melanoma to Brain Tumors


Reporter: Aviva Lev-Ari, PhD, RN
Cancer Res. 2016 Aug 1;76(15):4359-71. doi: 10.1158/0008-5472.CAN-16-0485. Epub 2016 Jun 3.

Incipient Melanoma Brain Metastases Instigate Astrogliosis and Neuroinflammation.


Malignant melanoma is the deadliest of skin cancers. Melanoma frequently metastasizes to the brain, resulting in dismal survival. Nevertheless, mechanisms that govern early metastatic growth and the interactions of disseminated metastatic cells with the brain microenvironment are largely unknown. To study the hallmarks of brain metastatic niche formation, we established a transplantable model of spontaneous melanoma brain metastasis in immunocompetent mice and developed molecular tools for quantitative detection of brain micrometastases. Here we demonstrate that micrometastases are associated with instigation of astrogliosis, neuroinflammation, and hyperpermeability of the blood-brain barrier. Furthermore, we show a functional role for astrocytes in facilitating initial growth of melanoma cells. Our findings suggest that astrogliosis, physiologically instigated as a brain tissue damage response, is hijacked by tumor cells to support metastatic growth. Studying spontaneous melanoma brain metastasis in a clinically relevant setting is the key to developing therapeutic approaches that may prevent brain metastatic relapse. Cancer Res; 76(15); 4359-71. ©2016 AACR.

©2016 American Association for Cancer Research.

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A Mechanism of Cancer Metastasis

Larry H. Bernstein, MD, FCAP, Curator


Screen Shot 2021-07-19 at 6.11.06 PM

Word Cloud By Danielle Smolyar

A Protein that Spreads Cancer

Nils Halberg at the University of Bergen has identified a protein that makes it possible for cancer cells to spread


The cells inside a tumour differ a lot. While some remains “good” and do not cause trouble, others become aggressive and starts to spread to other organ sites. It is very hard to predict which cells become aggressive or not.

Nevertheless, by isolating these aggressive cancer cells in in vivotests on animals, Nils Halberg at the Department of Biomedicinet the University of Bergen (UiB) and the researchers Dr. Sohail Tavazoie and Dr. Caitlin Sengelaub at The Rockefeller University have discovered a certain protein (PITPNC1) that characterise aggressive cancer cells.

“We discovered that the aggressive cancer cells that are spreading in colon, breast, and skin cancer contained a much higher portion of the protein PITPNC1, than the non-aggressive cancer cells,” says researcher Nils Halberg of the CELLNET Group at the Department of Biomedicine at UiB.

“This means we can predict which of the cancer cells are getting aggressive and spread, at a much earlier stage than today.”

How cells penetrate tissue

The researcher also discovered that this protein, that characterizes the aggressive cancer cells, has got a very specific function in the process of spreading cancer.

The cancer cells spread from one place in the body to another, through the blood vessel. To get into the blood vessels, the cell needs to penetrate tissue, both when it leaves the tumour and when it is attaching to a new organ.

“The protein PITPNC1 regulates a process whereby the cancer cells are secreting molecules, which cut through a network of proteins outside the cells, like scissors. The cancer cell is then able to penetrate the tissue and set up a colonies at new organ sites,” Halberg explains.

Custom-made therapy

A tumour that is not spreading, is usually not dangerous for the patient if it is removed. The hard part in cancer therapy is when the tumour starts to spread. Guided by the new discoveries, supported by the Bergen Research Foundation´s (BFS) Recruitment Programme, Halberg hopes to contribute to a better treatment of cancer patients.

“If we get to the point where we can offer a custom-made therapy that targets the function of this protein, we might be able to stop it spreading,” says Nils Halberg.


This gene encodes a member of the phosphatidylinositol transfer protein family. The encoded cytoplasmic protein plays a role in multiple processes including cell signaling and lipid metabolism by facilitating the transfer of phosphatidylinositol between membrane compartments. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene, and a pseudogene of this gene is located on the long arm of chromosome 1. [provided by RefSeq, May 2012]

Phosphatidylinositol Transfer Protein, Cytoplasmic 1 (PITPNC1) Binds and Transfers Phosphatidic Acid*

Kathryn Garner‡ , Alan N. Hunt§ , Grielof Koster§ , Pentti Somerharju¶ , Emily Groves‡1, Michelle Li‡ , Padinjat Raghu , Roman Holic‡ , and Shamshad Cockcroft‡2
JBC Papers in Press, July 21, 2012,      http://dx.doi.org:/10.1074/jbc.M112.375840

Background: Phosphatidylinositol transfer protein, cytoplasmic 1 (PITPNC1) (alternative name, RdgB) promotes metastatic colonization and angiogenesis in humans.

Results: We demonstrate that RdgB is a phosphatidic acid (PA)- and phosphatidylinositol-binding protein and binds PA derived from the phospholipase D pathway.

Conclusion: RdgB is the first lipid-binding protein identified that can bind and transfer PA.

Significance: PA bound to RdgB is a likely effector downstream of phospholipase D

PITPNC1 Recruits RAB1B to the Golgi Network to Drive Malignant Secretion

Nils Halberg3,4,, Caitlin A. Sengelaub3, Kristina Navrazhina, Henrik Molina, Kunihiro Uryu, Sohail F. Tavazoie
Cancer Cell 14 Mar 2016; Volume 29, Issue 3:339–353   http://dx.doi.org/10.1016/j.ccell.2016.02.013
  • PITPNC1 promotes metastasis by melanoma, breast cancer, and colon cancer cells
  • PITPNC1 recruits RAB1B to the Golgi compartment of the cell
  • Golgi localization of RAB1B enhances vesicular secretion via GOLPH3 recruitment


Enhanced secretion of tumorigenic effector proteins is a feature of malignant cells. The molecular mechanisms underlying this feature are poorly defined. We identify PITPNC1 as a gene amplified in a large fraction of human breast cancer and overexpressed in metastatic breast, melanoma, and colon cancers. Biochemical, molecular, and cell-biological studies reveal that PITPNC1 promotes malignant secretion by binding Golgi-resident PI4P and localizing RAB1B to the Golgi. RAB1B localization to the Golgi allows for the recruitment of GOLPH3, which facilitates Golgi extension and enhanced vesicular release. PITPNC1-mediated vesicular release drives metastasis by increasing the secretion of pro-invasive and pro-angiogenic mediators HTRA1, MMP1, FAM3C, PDGFA, and ADAM10. We establish PITPNC1 as a PI4P-binding protein that enhances vesicular secretion capacity in malignancy.

Cancerous Conduits

Metastatic cancer cells use nanotubes to manipulate blood vessels.

By Amanda B. Keener | April 1, 2016



MAKING CONTACT: Breast cancer cells (white arrows) in culture deliver microRNAs to endothelial cells through filamentous nanotubes (yellow arrow).


The paper
Y. Conner et al., “Physical nanoscale conduit-mediated communication between tumour cells and the endothelium modulates endothelial phenotype,” Nat Commun, 6:8671, 2015.

Branching Out
Harvard bioengineer Shiladitya Sengupta and his team were establishing a culture system to model the matrix and blood vessel networks that surround tumors when they found that human breast cancer cells spread out along blood vessel endothelial cells rather than form spheroid tumors as expected. Taking a closer look using scanning electron microscopy, they spied nanoscale filaments consisting of membrane and cytoskeletal components linking the two cell types.

Manipulative Metastases
These cancer cell–spawned nanotubes, the team discovered, could transfer a dye from cancer cells to endothelial cells both in culture and in a mouse model of breast cancer metastasis to the lungs.The cells also transferred microRNAs known to regulate endothelial cell adhesion and disassociation of tight junctions, which Sengupta speculates may help cancer cells slip in and out of blood vessels. This study is the first to suggest a role for nanotubes in metastasis.

Breaking the Chain
Sengupta’s team then used low doses of cytoskeleton-disrupting drugs to block nanotube formation. Emil Lou, an oncologist at the University of Minnesota who studies nanotubes in cancer and was not involved in the study, says this approach is a “good start,” though such drugs would not be used in human patients because they are not specific to nanotubes.

In the Details
Lou says the study emphasizes the importance of understanding interactions between tumors and their surrounding tissues on a molecular level. Going forward, Sengupta plans to study how the tubes are formed in melanoma as well as breast and ovarian cancers to try to identify other drug targets.

Physical nanoscale conduit-mediated communication between tumour cells and the endothelium modulates endothelial phenotype

Yamicia ConnorSarah TekleabShyama NandakumarCherelle Walls,….., Bruce ZetterElazer R. Edelman & Shiladitya Sengupta
Nature Communications6,Article number:8671

Metastasis is a major cause of mortality and remains a hurdle in the search for a cure for cancer. Not much is known about metastatic cancer cells and endothelial cross-talk, which occurs at multiple stages during metastasis. Here we report a dynamic regulation of the endothelium by cancer cells through the formation of nanoscale intercellular membrane bridges, which act as physical conduits for transfer of microRNAs. The communication between the tumour cell and the endothelium upregulates markers associated with pathological endothelium, which is reversed by pharmacological inhibition of these nanoscale conduits. These results lead us to define the notion of ‘metastatic hijack’: cancer cell-induced transformation of healthy endothelium into pathological endothelium via horizontal communication through the nanoscale conduits. Pharmacological perturbation of these nanoscale membrane bridges decreases metastatic foci in vivo. Targeting these nanoscale membrane bridges may potentially emerge as a new therapeutic opportunity in the management of metastatic cancer.

Metastasis is the culmination of a cascade of events, including invasion and intravasation of tumour cells, survival in circulation, extravasation and metastatic colonization4. Multiple studies have reported a dynamic interaction between the metastatic tumour cell and the target organ, mediated by cytokines4, 12 or by exosomes that can prime metastasis by creating a pre-metastatic niche13. Interestingly, the interactions between cancer cells and endothelium in the context of metastasis, which occurs during intravasation, circulation and extravasation, remains less studied. Cancer cell-secreted soluble factors can induce retraction of endothelial cells and the subsequent attachment and transmigration of tumour cells through the endothelial monolayers14, 15. Recently, studies indicate a more intricate communication between cancer cells and the endothelium. For example, a miRNA regulon was found to mediate endothelial recruitment and metastasis by cancer cells16. Similarly, exosome-mediated transfer of cancer-secreted miR-105 was recently reported to disrupt the endothelial barrier and promote metastasis17. We rationalized that a better understanding of cancer–endothelial intercellular communication, primarily during extravasation, could lead to novel strategies for inhibiting metastasis18.

Recently, nanoscale membrane bridges, such as tunnelling nanotubes (TNTs) and filopodias, have emerged as a novel mechanism of intercellular communication19. For example, specialized signalling filopodia or cytonemes were recently shown to transport morphogens during development20. Similarly, TNTs, which unlike filopodia have no contact with the substratum21, were shown to facilitate HIV-1 transmission between T cells, enable the spread of calcium-mediated signal between cells and transfer p-glycoproteins conferring multi-drug resistance between cancer cells22, 23, 24, 25. TNTs were also recently implicated in trafficking of mitochondria from endothelial to cancer cells and transfer miRNA between osteosarcoma cells and stromal murine osteoblast cells, and between smooth muscle cells and the endothelium26, 27, 28. However, whether similar intercellular nanostructure-mediated communication can be harnessed by cancer cells to modulate the endothelium is not known.

Here we report that metastatic cancer cells preferentially form nanoscale intercellular membrane bridges with endothelial cells. These nanoscale bridges act as physical conduits through which the cancer cells can horizontally transfer miRNA to the endothelium. We observe that the recipient endothelial cells present an miRNA profile that is distinct from non-recipient endothelial cells isolated from the same microenvironment. Furthermore, the co-cultures of cancer and endothelial cells upregulate markers associated with pathological endothelium, which is inhibited by pharmacological disruption of the nanoscale conduits. Additionally, the pharmacological inhibitors of these nanoscale conduits can decrease metastatic foci in vivo, which suggests that these nanoscale conduits may potentially emerge as new targets in the management of metastatic cancer.

Figure 1: Nanoscale structures physically connect metastatic cells and the endothelium

Nanoscale structures physically connect metastatic cells and the endothelium.


(a) Representative image of MDA-MB-231 cancer cells exhibiting an invasive phenotype in the presence of preformed endothelial tubes in co-culture. (b) Representative image of a mammosphere typically formed by MDA-MB-231 cells when cultured on 3D tumour matrix in the absence of endothelial cells. MDA-MB-231 cells were loaded with CFSE. Actin was labelled with rhodamine phalloidin and nuclei were counterstained with DAPI. (c) A representative SEM of epithelial (EPI) MDA-MB-231 cells aligning on HUVEC (ENDO) tubules in the co-culture. Lower panel shows higher magnification. (d) SEM image reveals nanoscale membrane bridges connecting (nCs) metastatic breast cancer (EPI) cells and endothelial vessels (arrows). (e) A representative transmission electron micrograph shows intercellular connectivity through the nanoscale membrane bridge between MDA-MB-231 and an endothelial cell. (f) A cartoon represents the types of homotypic and heterotypic intercellular nanoscale connections that an epithelial cell may form in the presence of endothelial tubules. Highly metastatic (MDA-MB-468, MDA-MB-231 or MDA-MB-435) or low metastatic (MCF7 and SkBr3) cancer cells were co-cultured with the endothelial tubes. Normal HMECs were used as control. Graphs show percentage of total population of epithelial cells that exhibit either homotyptic (Epi–Epi) or heterotypic (Epi–Endo) nanoscale connections and (g) average number of nanoscale connections formed per cell. Quantification analysis was done on >300 cells of each cell type. Data shown are mean±s.e.m. (n=6 replicates per study, with 2–3 independent experiments). **P<0.01, ***P<0.001 (analysis of variance followed by Bonferroni’s post-hoctest).

The nanoscale bridges are composed of cytoskeletal elements

Figure 3: Structure and function of the heterotypic intercellular nanoscale membrane bridges.

a) Representative images show the heterotypic nanoscale membrane bridges are composed of both F-actin and α/β-tubulin cytoskeletal components. Co-cultures were stained with α/β-tubulin antibody (green) and phalloidin (purple) to label actin, and counterstained with DAPI (nuclear)+WGA (plasma membrane) (blue). Endothelial cells were labelled with DiL-Ac-LDL (red). (b) Mathematical modelling of the structure of the nanoscale connections. The physical properties of actin filaments necessitate microtubules for projections of certain length scales. The maximum projection length for a given minimum diameter at the buckling limit is plotted for actin-only nanoscale structures (purple line). This curve is overlaid with the experimental length and diameter measurements (red dots) from the observed thin projections measured in these studies. Projections containing only actin or projections containing both actin and tubulin can exist to the right of the curve (purple line). However, actin-only projections cannot exist to the left of the curve (green region). (c) The effect of incorporating tubulin in these projections. The maximum length is plotted against the minimum diameter for varying fractions of tubulin incorporated in the nanoscale projection. Addition of microtubules to the projections increases the overall flexural rigidity, shifting the curves left of the actin-only limit (purple line), thus allowing for longer and thinner nanoscale connections. However, owing to the larger radius of microtubules (4 × radius of actin filaments), there is an optimal fraction of tubulin (green line) that can be incorporated into the projection before the effect is reversed. (d) The optimal fraction of microtubules is about 6.6% (red dashed line) to maximize nanostructure flexural strength, while minimizing thickness. (e) Representative confocal image shows the presence of myosin V motor proteins within the intercellular nanostructure (inset shows higher magnification). Scale bar 10μm.

Nanoscale bridges act as conduits for communication

Figure 4: The nanoscale membrane bridges act as conduits for intercellular communication between cancer and endothelial cells.

(a) Confocal image of nanoscale membrane bridge-mediated transfer of cytoplasmic contents. CFSE (green)-loaded MDA-MB-231 cells were co-cultured with the Dil-Ac-LDL (red)-labelled HUVECs. Transfer of the CFSE dye was observed after 24-h co-culture. CFSE dye can be seen within HUVEC cells (yellow arrow). Tumour cells can form a nanobridge with a distal endothelial cell (EC1) than an endothelial cell (EC2) in close proximity. (b,c) Cartoon shows the experimental design, where dual cultures control for vesicle-mediated intercellular transfer. FACS plot show gating for sorting endothelial cells from the co-cultures using dual staining for DiI-Ac-LDL and PECAM-1, and then quantification for CFSE transfer in the isolated endothelial cells. (d) Graph shows quantification of FACS analysis, highlighting increased transfer of CFSE to endothelial cells in the co-culture. (N>100,000 events, n=36 replicates, 3 replicates per study). (e) Graph shows the temporal kinetics of nanoscale connection-mediated intercellular transfer of CFSE from MDA-MB-231 cells to the endothelium (n=2 studies, 3 replicates per study). (f) Effect of small molecule inhibitors of cytoskeletal components on membrane nanobridges. (g) Graphs show treatment with vehicle (control) or a low-dose combination of docetaxel and cytochalasin do not affect the exosome shedding (n=2 independent studies). (h,i) Graphs show the effect of pharmacological inhibitors on the formation of heterotypic and homotypic nanoscale bridges (arrows). (n=2 studies, 6 replicates per study). (j) Graph shows the effect of pharmacological inhibitors on intercellular transfer of CFSE to endothelial cells from cancer cells (n=10 studies, 3 replicates per study). Data shown are mean±s.e.m. (*P<0.05,**P<0.01, ****P<0.001, analysis of variance followed by Bonferroni’s post-hoc test).

Effect of pharmacological inhibition of nanoscale bridges

Nanobridges transfer miRNA from cancer cells to endothelium

Figure 5: The nanoscale membrane bridges act as conduits for intercellular transfer of miRNA between cancer and endothelial cells.

Representative confocal images show the transfer of Cy3-labelled miRNA from MDA-MB-231 cells (EPI) to endothelial cells (ENDO) at (a) 24h and (b) 36h of co-culture. Alexa Fluor 488-Ac-LDL (green)-labelled endothelial cells were co-cultured with Cy3-labelled miRNA-transfected MDA-MB-231. Co-cultures were counterstained with phalloidin (purple) and DAPI+WGA (blue). A 3D visualization shows the localization of miRNA within the nanoscale connections (white arrows), which act as conduits for horizontal transfer of miRNAs to endothelial cells. (c) Schema shows quantification of Cy3-labelled control miRNA and Cy3-labelled miR132 transfer between cancer cell and endothelium using flow cytometry. Endothelial cell populations were isolated from the co-cultures and percentage of miRNA+ve cells was determined. Dual cultures in Boyden chambers were included as controls. (d) Graph shows the effect of pharmacological disruption of nanoscale conduits on miRNA transfer. (e) Schema shows experimental design for reverse transcriptase–PCR-based detection of transferred miR-132 in endothelial cells under different experimental conditions. MDA-MB-231 cells transfected with miR-132 and α-miR-132 were co-cultured with endothelial tubes. FACS-isolated endothelial cell populations were analysed for the expression of miR-132. (f) Graph shows miR-132+ve cell populations (solid red) show 5 × increase compared with miR-132−ve populations (solid blue) (P<0.0001), whereas anti-miR-132+ve cells (striped red) show 26 × decrease in miR-132 expression (P<0.0001) compared with α-miR-132−ve cells (striped blue). Direct transfection of miR-132 (black) and α-miR-132 (light blue) in endothelial cells is used as positive and negative controls, respectively. Upregulation of miR-132 from baseline was observed in dual culture (solid green), which could be inhibited with anti-miR-132 (striped green). MiR-132 levels are increased compared with dual only in those cells that are positive for intercellular transfer. Fold change was determined compared with endothelial cell transfection with control miRNA (grey). (g) FACS analysis shows nanoscale bridges-mediated transfer of miRNAs leads to changes in p120RasGAP and pAkt (S473) expression downstream of the miR-132 pathway in endothelial cell populations isolated from co-cultures. (h) Graphs show p120RasGAP expression is decreased in the miR-132+ve cell populations and increased in the α-miR-132+ve cell populations, while further downstream miR-132 positively regulates pAkt expression. Data shown are mean±s.e.m. (N=2–5 independent studies, with 3 replicates per study,*P<0.05, **P<0.01, ***P<0.001, ****P<0.0001, analysis of variance followed by Bonferroni’s post-hoctest).

Nanobridge-mediated transfer alters endogenous miRNA profile

Figure 6: Cancer cell–endothelial intercellular transfer alters the endogenous miRNA profile and phenotype of recipient endothelial cells.

The complexity of regulatory tumour parenchyma–endothelial communication is increasingly being unravelled7, 50. The altered phenotypic behaviour of the metastatic cancer cells in the presence of endothelial cells observed in this study, instead of forming classical mammospheres, is consistent with the emerging paradigm of modulatory tumour parenchyma–stroma communication and the creation of a pre-metastatic niche. Indeed, a recent study proposed the concept of the formation of a pre-metastatic niche mediated via metastatic cell-secreted exosomes, leading to vascular leakiness at the pre-metastatic sites13. Here we demonstrate that cancer cells form nanoscale membrane bridges, which can act as conduits for horizontal transfer of miRNA from the cancer cells to the endothelium, switching the latter to a pathological phenotype. Our findings reveal that the ability to form the nanoscale conduits with endothelial cells correlates with the metastatic potential of the cancer cell, and that the pharmacological perturbation of these nanoscale connections can lead to a reduction in the metastatic burden in experimental metastasis models. Together, our studies shed new insights into the tumour parenchyma–endothelial communication, adding depth to the emerging paradigm of the ability of a cancer cell to ‘hijack’ a physiological stromal cell for self-gain13.

Indeed, exosomes have emerged as an extensively studied mechanism of horizontal intercellular transfer of information51. However, a key distinction exists between the exosome-mediated versus the nanoscale membrane bridge-mediated intercellular communication. Although the former is stochastic, that is, it is unlikely the cancer cell has control over which cell will be targeted by a secreted exosome, the communication via nanoscale membrane bridges is deterministic, that is, the cancer cell can connect to a specific endothelial cell, which could be further away than the most proximal endothelial cell.

Although the aim of this study was to study the nanoscale membrane bridges as a mode of horizontal transfer of miRNAs from the metastatic cancer cells to the endothelium, and not to characterize a specific miRNA that are implicated in metastasis, many of the miRNAs, which were differentially regulated in the recipient endothelial cells, have previously been shown to regulate metastasis (Supplementary Discussion).

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