Feeds:
Posts
Comments

Posts Tagged ‘immune checkpoint’

Live Notes, Real Time Conference Coverage AACR 2020 #AACR20: Tuesday June 23, 2020 Noon-2:45 Educational Sessions


Live Notes, Real Time Conference Coverage AACR 2020: Tuesday June 23, 2020 Noon-2:45 Educational Sessions

Reporter: Stephen J. Williams, PhD

Follow Live in Real Time using

#AACR20

@pharma_BI

@AACR

Register for FREE at https://www.aacr.org/

 

Presidential Address

Elaine R Mardis, William N Hait

DETAILS

Welcome and introduction

William N Hait

 

Improving diagnostic yield in pediatric cancer precision medicine

Elaine R Mardis
  • Advent of genomics have revolutionized how we diagnose and treat lung cancer
  • We are currently needing to understand the driver mutations and variants where we can personalize therapy
  • PD-L1 and other checkpoint therapy have not really been used in pediatric cancers even though CAR-T have been successful
  • The incidence rates and mortality rates of pediatric cancers are rising
  • Large scale study of over 700 pediatric cancers show cancers driven by epigenetic drivers or fusion proteins. Need for transcriptomics.  Also study demonstrated that we have underestimated germ line mutations and hereditary factors.
  • They put together a database to nominate patients on their IGM Cancer protocol. Involves genetic counseling and obtaining germ line samples to determine hereditary factors.  RNA and protein are evaluated as well as exome sequencing. RNASeq and Archer Dx test to identify driver fusions
  • PECAN curated database from St. Jude used to determine driver mutations. They use multiple databases and overlap within these databases and knowledge base to determine or weed out false positives
  • They have used these studies to understand the immune infiltrate into recurrent cancers (CytoCure)
  • They found 40 germline cancer predisposition genes, 47 driver somatic fusion proteins, 81 potential actionable targets, 106 CNV, 196 meaningful somatic driver mutations

 

 

Tuesday, June 23

12:00 PM – 12:30 PM EDT

Awards and Lectures

NCI Director’s Address

Norman E Sharpless, Elaine R Mardis

DETAILS

Introduction: Elaine Mardis

 

NCI Director Address: Norman E Sharpless
  • They are functioning well at NCI with respect to grant reviews, research, and general functions in spite of the COVID pandemic and the massive demonstrations on also focusing on the disparities which occur in cancer research field and cancer care
  • There are ongoing efforts at NCI to make a positive difference in racial injustice, diversity in the cancer workforce, and for patients as well
  • Need a diverse workforce across the cancer research and care spectrum
  • Data show that areas where the clinicians are successful in putting African Americans on clinical trials are areas (geographic and site specific) where health disparities are narrowing
  • Grants through NCI new SeroNet for COVID-19 serologic testing funded by two RFAs through NIAD (RFA-CA-30-038 and RFA-CA-20-039) and will close on July 22, 2020

 

Tuesday, June 23

12:45 PM – 1:46 PM EDT

Virtual Educational Session

Immunology, Tumor Biology, Experimental and Molecular Therapeutics, Molecular and Cellular Biology/Genetics

Tumor Immunology and Immunotherapy for Nonimmunologists: Innovation and Discovery in Immune-Oncology

This educational session will update cancer researchers and clinicians about the latest developments in the detailed understanding of the types and roles of immune cells in tumors. It will summarize current knowledge about the types of T cells, natural killer cells, B cells, and myeloid cells in tumors and discuss current knowledge about the roles these cells play in the antitumor immune response. The session will feature some of the most promising up-and-coming cancer immunologists who will inform about their latest strategies to harness the immune system to promote more effective therapies.

Judith A Varner, Yuliya Pylayeva-Gupta

 

Introduction

Judith A Varner
New techniques reveal critical roles of myeloid cells in tumor development and progression
  • Different type of cells are becoming targets for immune checkpoint like myeloid cells
  • In T cell excluded or desert tumors T cells are held at periphery so myeloid cells can infiltrate though so macrophages might be effective in these immune t cell naïve tumors, macrophages are most abundant types of immune cells in tumors
  • CXCLs are potential targets
  • PI3K delta inhibitors,
  • Reduce the infiltrate of myeloid tumor suppressor cells like macrophages
  • When should we give myeloid or T cell therapy is the issue
Judith A Varner
Novel strategies to harness T-cell biology for cancer therapy
Positive and negative roles of B cells in cancer
Yuliya Pylayeva-Gupta
New approaches in cancer immunotherapy: Programming bacteria to induce systemic antitumor immunity

 

 

Tuesday, June 23

12:45 PM – 1:46 PM EDT

Virtual Educational Session

Cancer Chemistry

Chemistry to the Clinic: Part 2: Irreversible Inhibitors as Potential Anticancer Agents

There are numerous examples of highly successful covalent drugs such as aspirin and penicillin that have been in use for a long period of time. Despite historical success, there was a period of reluctance among many to purse covalent drugs based on concerns about toxicity. With advances in understanding features of a well-designed covalent drug, new techniques to discover and characterize covalent inhibitors, and clinical success of new covalent cancer drugs in recent years, there is renewed interest in covalent compounds. This session will provide a broad look at covalent probe compounds and drug development, including a historical perspective, examination of warheads and electrophilic amino acids, the role of chemoproteomics, and case studies.

Benjamin F Cravatt, Richard A. Ward, Sara J Buhrlage

 

Discovering and optimizing covalent small-molecule ligands by chemical proteomics

Benjamin F Cravatt
  • Multiple approaches are being investigated to find new covalent inhibitors such as: 1) cysteine reactivity mapping, 2) mapping cysteine ligandability, 3) and functional screening in phenotypic assays for electrophilic compounds
  • Using fluorescent activity probes in proteomic screens; have broad useability in the proteome but can be specific
  • They screened quiescent versus stimulated T cells to determine reactive cysteines in a phenotypic screen and analyzed by MS proteomics (cysteine reactivity profiling); can quantitate 15000 to 20,000 reactive cysteines
  • Isocitrate dehydrogenase 1 and adapter protein LCP-1 are two examples of changes in reactive cysteines they have seen using this method
  • They use scout molecules to target ligands or proteins with reactive cysteines
  • For phenotypic screens they first use a cytotoxic assay to screen out toxic compounds which just kill cells without causing T cell activation (like IL10 secretion)
  • INTERESTINGLY coupling these MS reactive cysteine screens with phenotypic screens you can find NONCANONICAL mechanisms of many of these target proteins (many of the compounds found targets which were not predicted or known)

Electrophilic warheads and nucleophilic amino acids: A chemical and computational perspective on covalent modifier

The covalent targeting of cysteine residues in drug discovery and its application to the discovery of Osimertinib

Richard A. Ward
  • Cysteine activation: thiolate form of cysteine is a strong nucleophile
  • Thiolate form preferred in polar environment
  • Activation can be assisted by neighboring residues; pKA will have an effect on deprotonation
  • pKas of cysteine vary in EGFR
  • cysteine that are too reactive give toxicity while not reactive enough are ineffective

 

Accelerating drug discovery with lysine-targeted covalent probes

 

Tuesday, June 23

12:45 PM – 2:15 PM EDT

Virtual Educational Session

Molecular and Cellular Biology/Genetics

Virtual Educational Session

Tumor Biology, Immunology

Metabolism and Tumor Microenvironment

This Educational Session aims to guide discussion on the heterogeneous cells and metabolism in the tumor microenvironment. It is now clear that the diversity of cells in tumors each require distinct metabolic programs to survive and proliferate. Tumors, however, are genetically programmed for high rates of metabolism and can present a metabolically hostile environment in which nutrient competition and hypoxia can limit antitumor immunity.

Jeffrey C Rathmell, Lydia Lynch, Mara H Sherman, Greg M Delgoffe

 

T-cell metabolism and metabolic reprogramming antitumor immunity

Jeffrey C Rathmell

Introduction

Jeffrey C Rathmell

Metabolic functions of cancer-associated fibroblasts

Mara H Sherman

Tumor microenvironment metabolism and its effects on antitumor immunity and immunotherapeutic response

Greg M Delgoffe
  • Multiple metabolites, reactive oxygen species within the tumor microenvironment; is there heterogeneity within the TME metabolome which can predict their ability to be immunosensitive
  • Took melanoma cells and looked at metabolism using Seahorse (glycolysis): and there was vast heterogeneity in melanoma tumor cells; some just do oxphos and no glycolytic metabolism (inverse Warburg)
  • As they profiled whole tumors they could separate out the metabolism of each cell type within the tumor and could look at T cells versus stromal CAFs or tumor cells and characterized cells as indolent or metabolic
  • T cells from hyerglycolytic tumors were fine but from high glycolysis the T cells were more indolent
  • When knock down glucose transporter the cells become more glycolytic
  • If patient had high oxidative metabolism had low PDL1 sensitivity
  • Showed this result in head and neck cancer as well
  • Metformin a complex 1 inhibitor which is not as toxic as most mito oxphos inhibitors the T cells have less hypoxia and can remodel the TME and stimulate the immune response
  • Metformin now in clinical trials
  • T cells though seem metabolically restricted; T cells that infiltrate tumors are low mitochondrial phosph cells
  • T cells from tumors have defective mitochondria or little respiratory capacity
  • They have some preliminary findings that metabolic inhibitors may help with CAR-T therapy

Obesity, lipids and suppression of anti-tumor immunity

Lydia Lynch
  • Hypothesis: obesity causes issues with anti tumor immunity
  • Less NK cells in obese people; also produce less IFN gamma
  • RNASeq on NOD mice; granzymes and perforins at top of list of obese downregulated
  • Upregulated genes that were upregulated involved in lipid metabolism
  • All were PPAR target genes
  • NK cells from obese patients takes up palmitate and this reduces their glycolysis but OXPHOS also reduced; they think increased FFA basically overloads mitochondria
  • PPAR alpha gamma activation mimics obesity

 

 

Tuesday, June 23

12:45 PM – 2:45 PM EDT

Virtual Educational Session

Clinical Research Excluding Trials

The Evolving Role of the Pathologist in Cancer Research

Long recognized for their role in cancer diagnosis and prognostication, pathologists are beginning to leverage a variety of digital imaging technologies and computational tools to improve both clinical practice and cancer research. Remarkably, the emergence of artificial intelligence (AI) and machine learning algorithms for analyzing pathology specimens is poised to not only augment the resolution and accuracy of clinical diagnosis, but also fundamentally transform the role of the pathologist in cancer science and precision oncology. This session will discuss what pathologists are currently able to achieve with these new technologies, present their challenges and barriers, and overview their future possibilities in cancer diagnosis and research. The session will also include discussions of what is practical and doable in the clinic for diagnostic and clinical oncology in comparison to technologies and approaches primarily utilized to accelerate cancer research.

 

Jorge S Reis-Filho, Thomas J Fuchs, David L Rimm, Jayanta Debnath

DETAILS

Tuesday, June 23

12:45 PM – 2:45 PM EDT

 

High-dimensional imaging technologies in cancer research

David L Rimm

  • Using old methods and new methods; so cell counting you use to find the cells then phenotype; with quantification like with Aqua use densitometry of positive signal to determine a threshold to determine presence of a cell for counting
  • Hiplex versus multiplex imaging where you have ten channels to measure by cycling of flour on antibody (can get up to 20plex)
  • Hiplex can be coupled with Mass spectrometry (Imaging Mass spectrometry, based on heavy metal tags on mAbs)
  • However it will still take a trained pathologist to define regions of interest or field of desired view

 

Introduction

Jayanta Debnath

Challenges and barriers of implementing AI tools for cancer diagnostics

Jorge S Reis-Filho

Implementing robust digital pathology workflows into clinical practice and cancer research

Jayanta Debnath

Invited Speaker

Thomas J Fuchs
  • Founder of spinout of Memorial Sloan Kettering
  • Separates AI from computational algothimic
  • Dealing with not just machines but integrating human intelligence
  • Making decision for the patients must involve human decision making as well
  • How do we get experts to do these decisions faster
  • AI in pathology: what is difficult? =è sandbox scenarios where machines are great,; curated datasets; human decision support systems or maps; or try to predict nature
  • 1) learn rules made by humans; human to human scenario 2)constrained nature 3)unconstrained nature like images and or behavior 4) predict nature response to nature response to itself
  • In sandbox scenario the rules are set in stone and machines are great like chess playing
  • In second scenario can train computer to predict what a human would predict
  • So third scenario is like driving cars
  • System on constrained nature or constrained dataset will take a long time for commuter to get to decision
  • Fourth category is long term data collection project
  • He is finding it is still finding it is still is difficult to predict nature so going from clinical finding to prognosis still does not have good predictability with AI alone; need for human involvement
  • End to end partnering (EPL) is a new way where humans can get more involved with the algorithm and assist with the problem of constrained data
  • An example of a workflow for pathology would be as follows from Campanella et al 2019 Nature Medicine: obtain digital images (they digitized a million slides), train a massive data set with highthroughput computing (needed a lot of time and big software developing effort), and then train it using input be the best expert pathologists (nature to human and unconstrained because no data curation done)
  • Led to first clinically grade machine learning system (Camelyon16 was the challenge for detecting metastatic cells in lymph tissue; tested on 12,000 patients from 45 countries)
  • The first big hurdle was moving from manually annotated slides (which was a big bottleneck) to automatically extracted data from path reports).
  • Now problem is in prediction: How can we bridge the gap from predicting humans to predicting nature?
  • With an AI system pathologist drastically improved the ability to detect very small lesions

 

Virtual Educational Session

Epidemiology

Cancer Increases in Younger Populations: Where Are They Coming from?

Incidence rates of several cancers (e.g., colorectal, pancreatic, and breast cancers) are rising in younger populations, which contrasts with either declining or more slowly rising incidence in older populations. Early-onset cancers are also more aggressive and have different tumor characteristics than those in older populations. Evidence on risk factors and contributors to early-onset cancers is emerging. In this Educational Session, the trends and burden, potential causes, risk factors, and tumor characteristics of early-onset cancers will be covered. Presenters will focus on colorectal and breast cancer, which are among the most common causes of cancer deaths in younger people. Potential mechanisms of early-onset cancers and racial/ethnic differences will also be discussed.

Stacey A. Fedewa, Xavier Llor, Pepper Jo Schedin, Yin Cao

Cancers that are and are not increasing in younger populations

Stacey A. Fedewa

 

  • Early onset cancers, pediatric cancers and colon cancers are increasing in younger adults
  • Younger people are more likely to be uninsured and these are there most productive years so it is a horrible life event for a young adult to be diagnosed with cancer. They will have more financial hardship and most (70%) of the young adults with cancer have had financial difficulties.  It is very hard for women as they are on their childbearing years so additional stress
  • Types of early onset cancer varies by age as well as geographic locations. For example in 20s thyroid cancer is more common but in 30s it is breast cancer.  Colorectal and testicular most common in US.
  • SCC is decreasing by adenocarcinoma of the cervix is increasing in women’s 40s, potentially due to changing sexual behaviors
  • Breast cancer is increasing in younger women: maybe etiologic distinct like triple negative and larger racial disparities in younger African American women
  • Increased obesity among younger people is becoming a factor in this increasing incidence of early onset cancers

 

 

Other Articles on this Open Access  Online Journal on Cancer Conferences and Conference Coverage in Real Time Include

Press Coverage

Live Notes, Real Time Conference Coverage 2020 AACR Virtual Meeting April 28, 2020 Symposium: New Drugs on the Horizon Part 3 12:30-1:25 PM

Live Notes, Real Time Conference Coverage 2020 AACR Virtual Meeting April 28, 2020 Session on NCI Activities: COVID-19 and Cancer Research 5:20 PM

Live Notes, Real Time Conference Coverage 2020 AACR Virtual Meeting April 28, 2020 Session on Evaluating Cancer Genomics from Normal Tissues Through Metastatic Disease 3:50 PM

Live Notes, Real Time Conference Coverage 2020 AACR Virtual Meeting April 28, 2020 Session on Novel Targets and Therapies 2:35 PM

 

Read Full Post »


Live Notes, Real Time Conference Coverage 2020 AACR Virtual Meeting April 27, 2020 Minisymposium on Drugging Undrugged Cancer Targets 1:30 pm – 5:00 pm

SESSION VMS.ET01.01 – Drugging Undrugged Cancer Targets

April 27, 2020, 1:30 PM – 3:30 PM
Virtual Meeting: All Session Times Are U.S. EDT

Session Type
Virtual Minisymposium
Track(s)
Experimental and Molecular Therapeutics,Drug Development
18 Presentations
1:30 PM – 1:30 PM
– ChairpersonPeter C. Lucas. University of Pittsburgh School of Medicine, Pittsburgh, PA

1:30 PM – 1:30 PM
– ChairpersonJohn S. Lazo. University of Virginia, Charlottesville, VA

1:30 PM – 1:35 PM
– IntroductionPeter C. Lucas. University of Pittsburgh School of Medicine, Pittsburgh, PA

1:35 PM – 1:45 PM
3398 – PTPN22 is a systemic target for augmenting antitumor immunityWon Jin Ho, Jianping Lin, Ludmila Danilova, Zaw Phyo, Soren Charmsaz, Aditya Mohan, Todd Armstrong, Ben H. Park, Elana J. Fertig, Zhong-Yin Zhang, Elizabeth M. Jaffee. Johns Hopkins Sidney Kimmel Comp. Cancer Center, Baltimore, MD, Purdue University, Baltimore, MD, Johns Hopkins Sidney Kimmel Comp. Cancer Center, Baltimore, MD, Vanderbilt University Medical Center, Baltimore, MD

Abstract: Remarkable progress in cancer immunology has revolutionized cancer therapy. The majority of patients, however, do not respond to immunotherapeutic options, warranting the ongoing search for better strategies. Leveraging the established role of protein tyrosine phosphatase non-receptor type 22 (PTPN22) in autoimmune diseases, we hypothesized that PTPN22 is a novel target for cancer immunotherapy. PTPN22 is a physiologic regulator of T cell receptor (TCR) signaling acting by dephosphorylating activating tyrosine residues in Lck and Zap70. We first confirmed the relevance of PTPN22 expression by exploring its expression in multiple human cancer types using The Cancer Genome Atlas (TCGA). PTPN22 expression positively correlated with T cell and M1 macrophage gene signatures and immune regulatory genes, especially inflamed tumor types. Next, we directly investigated the role of PTPN22 in antitumor immunity by comparing in vivo tumor characteristics in wild-type (WT) and PTPN22 knockout (KO) mice. Consistent with our hypothesis, PTPN22 KO mice resisted MC38 and EG7 tumors significantly compared with WT. Mass cytometry (CyTOF) profiling of the immune tumor microenvironment demonstrated that MC38 tumors in PTPN22 KO mice were infiltrated with greater numbers of T cells, particularly CD8+ T cells expressing granzyme B and PD1. To further delineate the effects of PTPN22 KO on TCR signaling, we established an optimized CyTOF panel of 9 phosphorylation sites involved in the TCR signaling pathway, including two enzymatic substrates of PTPN22 (Lck Y394 and Zap70 Y493) and 15 immune subtyping markers. CyTOF phospho-profiling of CD8 T cells from tumor-bearing mouse spleens and the peripheral blood of immunotherapy-naïve cancer patients showed that the phosphorylated state of Zap70 Y493 correlated strongly with granzyme B expression. Furthermore, phospho-profiling of tumor-infiltrating CD8+ T cells (a measure of T cell activation) revealed the highest TCR-pathway phosphorylation levels in memory CD8+ T cells that express PD1. The difference in phosphorylation levels between WT and PTPN22 KO was most pronounced for Lck Y394. Based on these findings, we then hypothesized that PD1 inhibition will further enhance the antitumor immune responses promoted by the lack of PTPN22. Indeed, PTPN22 KO mice bearing MC38 and EG7 tumors responded more significantly to anti-PD1 therapy when compared with tumor-bearing WT mice. Finally, we treated WT tumor bearing mice with two different small molecule inhibitors of PTPN22, one previously published compound, LTV1, and one novel compound, L1 (discovered through structure based synthesis). While both inhibitors phenocopied the PTPN22 KO mice in resisting MC38 tumor growth, L1 treatment gave an immune profile that resembled what was observed in tumor-bearing PTPN22 KO mice. Taken together, our results demonstrate that PTPN22 is a novel systemic target for augmenting antitumor immunity.

  • can they leverage autoimmune data to look at new targets for checkpoint inhibition; we have a long way to go in immunooncology as only less than 30-40% of cancer types respond
  • using Cancer Genome Atlas PTPN22 is associated with autoimmune disorders
  • PTPN22 KO increases many immune cells; macrophages t-cells and when KO in tumors get more t cell infiltrate
  • PTP KO enhances t cell response, and may be driving t cells to exhaustion
  • made a inhibitor or PTPN22; antitumor phenotype when given inhibitor was like KO mice; a PDL1 inhibitor worked in KO mice
  • PTPN22 only in select hematopoetic cells

1:45 PM – 1:50 PM
– Discussion

1:50 PM – 2:00 PM
3399 – Preclinical evaluation of eFT226, a potent and selective eIF4A inhibitor with anti-tumor activity in FGFR1,2 and HER2 driven cancers. Peggy A. Thompson, Nathan P. Young, Adina Gerson-Gurwitz, Boreth Eam, Vikas Goel, Craig R. Stumpf, Joan Chen, Gregory S. Parker, Sarah Fish, Maria Barrera, Eric Sung, Jocelyn Staunton, Gary G. Chiang, Kevin R. Webster. eFFECTOR Therapeutics, San Diego, CA @RuggeroDavide

Abstract: Mutations or amplifications affecting receptor tyrosine kinases (RTKs) activate the RAS/MAPK and PI3K/AKT signaling pathways thereby promoting cancer cell proliferation and survival. Oncoprotein expression is tightly controlled at the level of mRNA translation and is regulated by the eukaryotic translation initiation factor 4F (eIF4F) complex consisting of eIF4A, eIF4E, and eIF4G. eIF4A functions to catalyze the unwinding of secondary structure in the 5’-untranslated region (5’-UTR) of mRNA facilitating ribosome scanning and translation initiation. The activation of oncogenic signaling pathways, including RAS and PI3K, facilitate formation of eIF4F and enhance eIF4A activity promoting the translation of oncogenes with highly structured 5’-UTRs that are required for tumor cell proliferation, survival and metastasis. eFT226 is a selective eIF4A inhibitor that converts eIF4A into a sequence specific translational repressor by increasing the affinity between eIF4A and 5’-UTR polypurine motifs leading to selective downregulation of mRNA translation. The polypurine element is highly enriched in the 5’-UTR of eFT226 target genes, many of which are known oncogenic drivers, including FGFR1,2 and HER2, enabling eFT226 to selectively inhibit dysregulated oncogene expression. Formation of a ternary complex [eIF4A-eFT226-mRNA] blocks ribosome scanning along the 5’-UTR leading to dose dependent inhibition of RTK protein expression. The 5’-UTR sequence dependency of eFT226 translational inhibition was evaluated in cell-based reporter assays demonstrating 10-45-fold greater sensitivity for reporter constructs containing an RTK 5’-UTR compared to a control. In solid tumor cell lines driven by alterations in FGFR1, FGFR2 or HER2, downregulation of RTK expression by eFT226 resulted in decreased MAPK and AKT signaling, potent inhibition of cell proliferation and an induction of apoptosis suggesting that eFT226 could be effective in treating tumor types dependent on these oncogenic drivers. Solid tumor xenograft models harboring FGFR1,2 or HER2 amplifications treated with eFT226 resulted in significant in vivo tumor growth inhibition and regression at well tolerated doses in breast, non-small cell lung and colorectal cancer models. Treatment with eFT226 also decreased RTK protein levels supporting the potential to use these eFT226 target genes as pharmacodynamic markers of target engagement. Further evaluation of predictive markers of sensitivity or resistance showed that RTK tumor models with mTOR mediated activation of eIF4A are most sensitive to eFT226. The association of eFT226 activity in RTK tumor models with mTOR pathway activation provides a means to further enrich for sensitive patient subsets during clinical development. Clinical trials with eFT226 in patients with solid tumor malignancies have initiated.
  • ternary complex formed blocks transcription selectively downregulating RTKs
  • drug binds in 5′ UTR and inhibits translation
  • RTKs activate eIF4 and are also transcribed through them so inhibition destroys this loop;  also with KRAS too
  • main antitumor activity are by an apoptotic mechanisms; refractory tumors are not sensitive to drug induced apoptosis
  • drug inhibits FGFR2 in colorectal cancer
  • drug also effective in HER2+ tumors
  • mTOR mediated eIF4 inhibited by drug
  • they get prolonged antitumor activity after washout of drug because forms this tight terniary complex

2:00 PM – 2:05 PM
– Discussion

2:05 PM – 2:15 PM
3400 – Adenosine receptor antagonists exhibit potent and selective off-target killing of FOXA1-high cancers: Steven M. Corsello, Ryan D. Spangler, Ranad Humeidi, Caitlin N. Harrington, Rohith T. Nagari, Ritu Singh, Vickie Wang, Mustafa Kocak, Jordan Rossen, Amael Madec, Nancy Dumont, Todd R. Golub. Dana-Farber Cancer Institute, Boston, MA, Broad Institute of MIT and Harvard, Cambridge, MA @corsellos

Abstract: Drugs targeting adenosine receptors were originally developed for the treatment of Parkinson’s disease and are now being tested in immuno-oncology clinical trials in combination with checkpoint inhibitors. We recently reported the killing activity of 4,518 drugs against 578 diverse cancer cell lines determined using the PRISM molecular barcoding approach. Surprisingly, three established adenosine receptor antagonists (CGS-15943, MRS-1220, and SCH-58261) showed potent and selective killing of FOXA1-high cancer cell lines without the need for immune cells. FOXA1 is a lineage-restricted transcription factor in luminal breast cancer, hepatocellular carcinoma, and prostate cancer without known small molecule inhibitors. We find that cytotoxic activity is limited to adenosine antagonists with a three-member aromatic core bound to a furan group, thus indicating a potential off-target mechanism of action. To identify genomic modulators of drug response, we performed genome-wide CRISPR/Cas9 knockout modifier screens. Killing by CGS-15943 and MRS-1220 was rescued by knockout of the aryl hydrocarbon receptor (AHR) and its nuclear partner ARNT. In confirmatory studies, knockout of AHR completely rescued killing by CGS-15943 in multiple cell types. Co-treatment with an AHR small molecule antagonist also rescued cell viability. Knockout of adenosine receptors did not alter drug response. Given that AHR is a known transcriptional regulator, we performed global mRNA sequencing to assess transcriptional changes induced by CGS-15943. The top two genes induced were the p450 enzymes CYP1A1 and CYP1B1. To determine sufficiency, we overexpressed CYP1A1 in a resistant cell line. Ectopic CYP1A1 expression sensitized to CGS-15943-mediated killing. Mass spectrometry revealed covalent trapping of a reactive metabolite by glutathione and potassium cyanide following in vitro incubation with liver microsomes. In addition, treatment of breast cancer cells with CGS-15943 for 24 hours resulted in increased γ-H2AX phosphorylation by western blot, indicative of DNA double stranded breaks. In summary, we identified off-target anti-cancer activity of multiple established adenosine receptor antagonists mediated by activation of AHR. Future studies will evaluate the functional contribution of FOXA1 and activity in vivo. Starting from a phenotypic screening hit, we leverage functional genomics to unlock the underlying mechanism of action. This project will pave the way for developing more effective therapies for biomarker-selected cancers, with potential to improve the care of patients with liver, breast, and prostate cancer.

  • developed a chemical library of over 6000 compounds (QC’d) to determine drugs that have antitumor effects
  • used a PRISM barcoded library to make cell lines to screen genotype-phenotype screens
  • for nononcology drugs fourteen drugs had activity in the PRISM assay
  • FOXA1 transcription factor high cancer cells seemed to be inhibited best with adenosine receptor inhibitor found in PRISM assay

2:15 PM – 2:20 PM
– Discussion

2:20 PM – 2:30 PM
3401 – Targeting lysosomal homeostasis in ovarian cancer through drug repurposing: Stefano Marastoni, Aleksandra Pesic, Sree Narayanan Nair, Zhu Juan Li, Ali Madani, Benjamin Haibe-Kains, Bradly G. Wouters, Anthony Joshua. University Health Network, Toronto, ON, Canada, Janssen Inc, Toronto, ON, Canada, The Kinghorn Cancer Centre, Sydney, Australia

Background: Drug repurposing has become increasingly attractive as it avoids the long processes and costs associated with drug discovery. Itraconazole (Itra) is a broad-spectrum anti-fungal agent which has an established broad spectrum of activity in human cell lines including cholesterol antagonism and inhibition of Hedgehog and mTOR pathways. Many in vitro, in vivo and clinical studies have suggested anti-proliferative activity both alone and in combination with other chemotherapeutic agents, in particular in ovarian cancer. This study is aimed at supporting the therapeutic potential of Itra and discovering and repurposing new drugs that can increase Itra anticancer activity as well as identifying new targets in the treatment of ovarian cancer.
Methods: We tested a panel of 32 ovarian cancer cell lines with different doses of Itra and identified a subset of cells which showed significant sensitivity to the drug. To identify genetic vulnerabilities and find new therapeutic targets to combine with Itra, we performed a whole genome sensitivity CRISPR screen in 2 cell lines (TOV1946 and OVCAR5) treated with non-toxic (IC10) concentrations of Itra.
Results: Pathway analysis on the top hits from both the screens showed a significant involvement of lysosomal compartments, and in particular dynamics between trans Golgi network and late endosomes/lysosomes, pathways that are affected by the autophagy inhibitor Chloroquine (CQ). We subsequently demonstrated that the combination of Itra and CQ had a synergistic effect in many ovarian cancer cell lines, even in those resistant to Itra. Further, genetic and pharmacological manipulation of autophagy indicated that upstream inhibition of autophagy is not a key mediator of the Itra/CQ mechanism of action. However, combination of Itra with other lysosomotropic agents (Concanamycin A, Bafilomycin A and Tamoxifen) displayed overlapping activity with Itra/CQ, supporting the lysosomal involvement in sensitizing cells to Itra resulted from the CRISPR screens. Analysis of lysosomal pattern and function showed a combined effect of Itra and CQ in targeting lysosomes and neutralizing their activity.
Conclusion: We identified two FDA approved drugs – CQ and Tamoxifen – that can be used in combination with Itra and exert a potent anti-tumor effect in ovarian cancer by affecting lyosomal function and suggesting a likely dependency of these cells on lysosomal biology. Further studies are in progress.

  • repurposing itraconozole in ovarian cancer potential mechanism of action is pleitropic
  • increasing doses of chloroquine caused OVCA cell death by accumulating in Golgi

2:30 PM – 2:35 PM
– Discussion

2:35 PM – 2:45 PM
3402 – BCAT1 as a druggable target in immuno-oncologyAdonia E. Papathanassiu, Francesca Lodi, Hagar Elkafrawy, Michelangelo Certo, Hong Vu, Jeong Hun Ko, Jacques Behmoaras, Claudio Mauro, Diether Lambrechts. Ergon Pharmaceuticals, Washington, DC, VIB Cancer Centre-KULeuven, Leuven, Belgium, Alexandria University, Alexandria, Egypt, University of Birmingham, Birmingham, United Kingdom, Ergon Pharmaceuticals, Washington, DC, Imperial College London, London, United Kingdom

2:45 PM – 2:50 PM
– Discussion

2:50 PM – 3:00 PM
3403 – Drugging the undruggable: Lessons learned from protein phosphatase 2A: Derek Taylor, Goutham Narla. Case Western Reserve University, Cleveland, OH, University of Michigan, Ann Arbor, MI @gouthamnarla

Abstract: Protein phosphatase 2A (PP2A) is a key tumor suppressor responsible for the dephosphorylation of many oncogenic signaling pathways. The PP2A holoenzyme is comprised of a scaffolding subunit (A), which serves as the structural platform for the catalytic subunit (C) and for an array of regulatory subunits (B) to assemble. Impairment of PP2A is essential for the pathogenesis of many diseases including cancer. In cancer, PP2A is inactivated through a variety of mechanisms including somatic mutation of the Aαsubunit. Our studies show that the most recurrent Aαmutation, P179R, results in an altered protein conformation which prevents the catalytic subunit from binding. Additionally, correcting this mutation, by expressing wild type PP2A Aαin cell lines harboring the P179R mutation, causes a reduction in tumor growth and metastasis. Given its central role in human disease pathogenesis, many strategies have been developed to therapeutically target PP2A.Our lab developed a series of small molecules activators of protein phosphatase 2A. One of our more advanced analogs in this series, DT-061, drives dephosphorylation and degradation of select pathogenic substrates of PP2A such as c-MYC in cellular and in vivo systems. Additionally, we have demonstrated the phosphomimetics of MYC that prevent PP2A mediated dephosphorylation and degradation markedly reduce the anti-tumorigenic activity of this series of PP2A activators further validating the target-substrate specificity of this approach. Specific mutations in the site of drug interaction or overexpression of the DNA tumor virus small T antigen which has been shown to specifically bind to and inactivate PP2A abrogate the in vivo activity of this small molecule series further validating the PP2A specificity of this approach. Importantly, treatment with DT-061 results in tumor growth inhibition in an array of in vivocancer models and marked regressions in combination with MEKi and PARPi.To further define the mechanism of action of this small molecule series, we have used cryo-electron microscopy (cryo-EM) to visualize directly theinteraction between DT-061 and a PP2A heterotrimeric complex. We have identified molecular interactions between DT-061 and all three PP2A subunits that prevent dissociation of the active enzyme through the marked prolongation of the kOFF of the native complex. Furthermore, we demonstrate that DT-061 specifically stabilizes the B56α-PP2A holoenzyme in a fully assembled, active state to dephosphorylate oncogenic targets such as c-MYC in both cellular and in vivo systems. This 3.6 Å structure identifies dynamic molecular interactions between the three distinct PP2A subunits and highlight the inherent mechanisms of PP2A complex assembly and disassembly in both cell free and cellular systems. Thus, our findings provide fundamental insights into PP2A complex assembly and regulation, identify a unique interfacial stabilizing mode of action for the therapeutic targeting of previously undruggable proteins, and aid in the development of phosphatase-based therapeutics tailored against disease specific phosphor-protein targets. The marriage of multidisciplinary scientific practices has allowed us to present here a previously unrecognized therapeutic strategy of complex stabilization for the activation of endogenous disease combating enzymes.

  • Reactivating PP2A; dephosphorylation of proteins (serine/threonine phosphatases); regulates multiple processes in the cell
  • SV40T has an antigen that inactivates PP2A; recurrent mutations in high grade endometrial cancers
  • P179R mutation promotes uterine tumor formation (also in a distal tubule ligation model)
  • project started in a phenotypic screen that tricyclic antidepressants could have an off target which was phosphatase activators (uncoupling GPCR from anticancer activity)
  • small T antigen block the activity of these small molecule activators;
  • acts as a molecular glue to bring the activators with a heterotrimer of phosphatases
  • so their small molecule activators effective in triple negative breast cancers;  one of targets of PP2A is MYC
  • question: have not yet seen resistance to these compounds but are currently looking at this

 

3:00 PM – 3:05 PM
– Discussion

3:05 PM – 3:15 PM
3404 – Inhibition of BCL10-MALT1 interaction to treat diffuse large B-cell lymphomaH: eejae Kang, Dong Hu, Marcelo Murai, Ahmed Mady, Bill Chen, Zaneta Nikolovska-Coleska, Linda M. McAllister-Lucas, Peter C. Lucas. University of Pittsburgh School of Medicine, Pittsburgh, PA, Merck, Kenilworth, NJ, University of Michigan School of Medicine, Ann Arbor, MI, University of Pittsburgh School of Medicine, Pittsburgh, PA, University of Michigan School of Medicine, Ann Arbor, MI, UPMC Children’s Hospital, Pittsburgh, PA

Abstract: The CARMA1/BCL10/MALT1 (CBM) signaling complex mediates antigen receptor-induced activation of NF-kB in lymphocytes to support normal adaptive immunity. As the effector protein of the complex, MALT1 exhibits two activities: protease and scaffolding activities. Gain-of-function mutations in the CARMA1 moiety or its upstream regulators trigger antigen-independent assembly of oligomeric CBM complexes, leading to constitutive activation of MALT1, unregulated NF-kB activity, and development of Activated B-Cell subtype of Diffuse Large B-Cell Lymphoma (ABC-DLBCL). Existing MALT1 inhibitors block only MALT1 protease activity, causing incomplete and unbalanced inhibition of MALT1, and have the potential for inducing autoimmune side effects. Since MALT1 is recruited to the CBM complex via its interaction with BCL10, we sought to identify inhibitors of BCL10-MALT1 interaction in order to target both the protease and scaffolding activities of MALT1 to treat ABC-DLBCL.
Our previous work suggested that an antibody-epitope-like interface governs the interaction between BCL10 and MALT1, so that a therapeutic opportunity exists for developing a small molecule inhibitor of the interaction to terminate inappropriate CBM activity. Using co-immunoprecipitation studies, a mammalian two-hybrid system, and surface plasmon resonance (SPR), we confirmed that BCL10 residues 107-119 and the tandem Ig-like domains of MALT1 are critical for this interaction. We then performed a structure-guided in silico screen of 3 million compounds, based on a computational model of the BCL10-MALT1 interaction interface, to identify compounds with potential for disrupting the interaction.
Compound 1 from the initial screening hits showed dose-responsive inhibition of BCL10-MALT1 interaction in both SPR and ELISA-based assays. Functionally, Compound 1 inhibits both MALT1 protease and scaffolding activities in Jurkat T cells, as demonstrated by its inhibition of CD3/CD28-induced RelB and N4BP1 cleavage, and inhibition of IKK phosphorylation, respectively. Compound 1 also blocks IL-2 transcription and IL-2 secretion by PMA/ionomycin-treated Jurkat T cells, as well as constitutive CBM-dependent secretion of IL-6 and IL-10 by ABC-DLBCL cells. Accordingly, Compound 1 selectively suppresses the growth of ABC-DLBCL cell lines, but does not affect the growth of MALT1-independent GCB-DLBCL cell lines.
In conclusion, we have identified an early-stage small molecule compound that inhibits the BCL10-MALT1 interaction, MALT1 protease and scaffolding activities, downstream CBM-dependent signaling, and ABC-DLBCL cell growth. Structure-guided modification of this lead compound is underway to further develop a new class of protein-protein interaction inhibitors that could provide more efficacious blockade of MALT1, while offering protection from undesirable autoimmune side effects in the treatment of this aggressive form of lymphoma.

3:15 PM – 3:20 PM
– Discussion

3:20 PM – 3:30 PM
– Closing RemarksJohn S. Lazo. University of Virginia, Charlottesville, VA

Read Full Post »


Vectorisation Of Immune Checkpoint Inhibitor Antibodies

Reporter: David Orchard-Webb, PhD

 

The FDA approved ipilimumab (anti-CTLA-4) and nivolumab (anti-PD-1) combination in October 2015 for the treatment of advanced melanoma. The antibodies have recently been approved in the UK for the same indication. Over half of patients respond to the combination [1]. These drugs belong to the class of monoclonal antibodies known as immune checkpoint inhibitors. The binding of anti-CTLA-4 antibodies to activated T cells prevents the surface CTLA-4 receptor from binding CD80 and/or CD86 on antigen presenting cells (APCs). Normally CTLA-4 binding to APCs deactivates the T-cell. Antibodies against programmed cell death protein 1 (PD-1) work by a similar mechanism to CTLA-4. These drugs are delivered by repeated intravenous injections (iv) [2].

 

Oncolytic viruses are an emerging class of immunotherapeutics that actively stimulate the immune system by releasing tumour antigens via lysis and by virtue of anti-viral immunity. The first FDA approved oncolytic virus (Imlygic), developed by Amgen/ BioVex, was given the green light in October 2015 for advanced melanoma patients delivered via direct tumour injection. The mechanism of action of oncolytic viruses is highly complementary with checkpoint inhibitor antibodies and multiple trials combining these two classes of agent are under way.

 

At the recent American Association for Cancer Research (AACR) annual meeting in New Orleans, Louisiana, the oldest biotechnology company in France – Transgene, presented preclinical data concerning oncolytic vaccinia viruses that express whole antibody (mAb), Fragment antigen-binding (Fab) or single-chain variable fragment (scFv) against mouse PD-1 [3]. These combinations proved superior over virus alone in mouse xenografts of melanoma and fibrosarcoma cell lines. Transgene claim that “these results pave the way for next generation of oncolytic vaccinia armed with immunomodulatory therapeutic proteins such as mAbs” (Figure 1) [3].

 

 698848905_d8bf7f415f_z
Figure 1: The convergence of therapeutics based on oncolytic viruses and monoclonal antibodies against immune checkpoint inhibotor proteins. Image Source: Eric Molina. No changes were made. Creative Commons Attribution 2.0 Generic (CC BY 2.0).

 

The combination of immune checkpoint inhibitors and oncolytic virus as a single molecular entity clearly has advantages in terms of manufacturing cost effectiveness. In addition viral vectors have the capacity for perfect specificity to tumours which has potential safety advantages.

 

REFERENCES

 

  1. http://www.bbc.com/news/health-365496740
  2. http://www.cancer.org/cancer/skincancer-melanoma/detailedguide/melanoma-skin-cancer-treating-immunotherapy
  3. http://www.transgene.fr/wp-content/uploads/2016/04/1604-Poster-AACR-format-122-244-v2.pdf

 

Other Related Articles Published In This Open Access Online Journal Include The Following:

 

https://pharmaceuticalintelligence.com/2016/04/12/oncolytic-virus-immunotherapy/

https://pharmaceuticalintelligence.com/2015/09/23/oncolytic-viruses-a-new-class-of-immunotherapy-drugs-against-cancer/

https://pharmaceuticalintelligence.com/2016/06/16/first-drug-in-checkpoint-inhibitor-class-of-cancer-immunotherapies-has-demonstrated-superiority-over-standard-of-care-in-the-treatment-of-first-line-lung-cancer-patients-mercks-keytryda/

https://pharmaceuticalintelligence.com/2016/05/07/durable-responses-with-checkpoint-inhibitor/

https://pharmaceuticalintelligence.com/2016/05/02/cancer-research-institute-nyc-623-6242016-will-combination-of-adoptive-t-cell-therapy-and-anti-checkpoint-inhibitor-therapies-be-the-next-wave/

https://pharmaceuticalintelligence.com/2016/02/14/checkpoint-inhibitors-for-gastrointestinal-cancers/

Read Full Post »