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T-cell receptors (TCR) can recognize the intracellular targets whereas antibodies only recognize the 25% of potential extracellular targets
survivin is expressed in multiple cancers and correlates with poor survival and prognosis
CD3 bispecific TCR to survivn (Ab to CD3 on T- cells and TCR to survivin on cancer cells presented in MHC Class A3)
ABBV184 effective in vivo in lung cancer models as single agent;
in humanized mouse tumor models CD3/survivin bispecific can recruit T cells into solid tumors; multiple immune cells CD4 and CD8 positive T cells were found to infiltrate into tumor
therapeutic window as measured by cytokine release assays in tumor vs. normal cells very wide (>25 fold)
ABBV184 does not bind platelets and has good in vivo safety profile
First- in human dose determination trial: used in vitro cancer cell assays to determine 1st human dose
looking at AML and lung cancer indications
phase 1 trial is underway for safety and efficacy and determine phase 2 dose
survivin has very few mutations so they are not worried about a changing epitope of their target TCR peptide of choice
The discovery of TNO155: A first in class SHP2 inhibitor
SHP2 is an intracellular phosphatase that is upstream of MEK ERK pathway; has an SH2 domain and PTP domain
knockdown of SHP2 inhibits tumor growth and colony formation in soft agar
55 TKIs there are very little phosphatase inhibitors; difficult to target the active catalytic site; inhibitors can be oxidized at the active site; so they tried to target the two domains and developed an allosteric inhibitor at binding site where three domains come together and stabilize it
they produced a number of chemical scaffolds that would bind and stabilize this allosteric site
block the redox reaction by blocking the cysteine in the binding site
lead compound had phototoxicity; used SAR analysis to improve affinity and reduce phototox effects
was very difficult to balance efficacy, binding properties, and tox by adjusting stuctures
TNO155 is their lead into trials
SHP2 expressed in T cells and they find good combo with I/O with uptick of CD8 cells
TNO155 is very selective no SHP1 inhibition; SHP2 can autoinhibit itself when three domains come together and stabilize; no cross reactivity with other phosphatases
they screened 1.5 million compounds and got low hit rate so that is why they needed to chemically engineer and improve on the classes they found as near hits
at the NCI they are pivoting some of their clinical trials to address COVID related issues like trials on tocilizumab and producing longitudinal cohorts of cancer patients and COVID for further analysis and studies
vaccine and antibody efforts at NCI and they are asking all their cancer centers (Cancer COVID Consortium) collecting data
Moonshot is collecting metadata but now COVID data from cellular therapy patients
they are about to publish new grants related to COVID and adding option to investigators to use current funds to do COVID related options
she says if at home take the time to think, write manuscripts, analyze data BE A REVIEWER FOR JOURNALS,
SSMMART project from Moonshot is still active
so far NCI and NIH grant process is ongoing although the peer review process is slower
they have extended deadlines with NO justification required (extend 90 days)
also allowing flexibility on use of grant money and allowing more early investigator rules and lax on those rules
non competitive renewals (type 5) will allow restructuring of project; contact program administrator
she and NCI heard rumors of institutions shutting down cancer research she is stressing to them not to do that
non refundable travel costs may be charged to the grant
NCI contemplating on extending the early investigator time
for more information go to NIH and NCI COVID-19 pages which have more guidances updated regularly
Targeting chromatin remodeling-associated genetic vulnerabilities in cancer: PBRM1 defects are synthetic lethal with PARP and ATR inhibitors
Presenter/AuthorsRoman Merial Chabanon, Daphné Morel, Léo Colmet-Daage, Thomas Eychenne, Nicolas Dorvault, Ilirjana Bajrami, Marlène Garrido, Suzanna Hopkins, Cornelia Meisenberg, Andrew Lamb, Theo Roumeliotis, Samuel Jouny, Clémence Astier, Asha Konde, Geneviève Almouzni, Jyoti Choudhary, Jean-Charles Soria, Jessica Downs, Christopher J. Lord, Sophie Postel-Vinay. Gustave Roussy, Villejuif, France, The Francis Crick Institute, London, United Kingdom, Institute of Cancer Research, London, United Kingdom, Sage Bionetworks, Seattle, WA, Institute of Cancer Research, London, United Kingdom, Institute of Cancer Research, London, United Kingdom, Institut Curie, Paris, France, Université Paris-Sud/Université Paris-Saclay, Le Kremlin-Bicêtre, France, Gustave Roussy Cancer Campus and U981 INSERM, ATIP-Avenir group, Villejuif, FranceDisclosures R.M. Chabanon: None. D. Morel: None. L. Colmet-Daage: None. T. Eychenne: None. N. Dorvault: None. I. Bajrami: None. M. Garrido: None. S. Hopkins: ; Fishawack Group of Companies. C. Meisenberg: None. A. Lamb: None. T. Roumeliotis: None. S. Jouny: None. C. Astier: None. A. Konde: None. G. Almouzni: None. J. Choudhary: None. J. Soria: ; Medimmune/AstraZeneca. ; Astex. ; Gritstone. ; Clovis. ; GSK. ; GamaMabs. ; Lilly. ; MSD. ; Mission Therapeutics. ; Merus. ; Pfizer. ; PharmaMar. ; Pierre Fabre. ; Roche/Genentech. ; Sanofi. ; Servier. ; Symphogen. ; Takeda. J. Downs: None. C.J. Lord: ; AstraZeneca. ; Merck KGaA. ; Artios. ; Tango. ; Sun Pharma. ; GLG. ; Vertex. ; Ono Pharma. ; Third Rock Ventures. S. Postel-Vinay: ; Merck KGaA. ; Principal investigator of clinical trials for Gustave Roussy.; Boehringer Ingelheim. ; Principal investigator of clinical trials for Gustave Roussy.; Roche. ; Principal investigator of clinical trials for Gustave Roussy. Benefited from reimbursement for attending symposia.; AstraZeneca. ; Principal investigator of clinical trials for Gustave Roussy.; Clovis. ; Principal investigator of clinical trials for Gustave Roussy.; Bristol-Myers Squibb. ; Principal investigator of clinical trials for Gustave Roussy.; Agios. ; Principal investigator of clinical trials for Gustave Roussy.; GSK.AbstractAim: Polybromo-1 (PBRM1), a specific subunit of the pBAF chromatin remodeling complex, is frequently inactivated in cancer. For example, 40% of clear cell Renal Cell Carcinoma (ccRCC) and 15% of cholangiocarcinoma present deleterious PBRM1 mutations. There is currently no precision medicine-based therapeutic approach that targets PBRM1 defects. To identify novel, targeted therapeutic strategies for PBRM1-defective cancers, we carried out high-throughput functional genomics and drug screenings followed by in vitro and in vivo validation studies.
Methods: High-throughput siRNA-drug sensitization and drug sensitivity screens evaluating > 150 cancer-relevant small molecules in dose-response were performed in Pbrm1 siRNA-transfected mouse embryonic stem cells (mES) and isogenic PBRM1-KO or -WT HAP1 cells, respectively. After identification of PBRM1-selective small molecules, revalidation was carried out in a series of in-house-generated isogenic models of PBRM1 deficiency – including 786-O (ccRCC), A498 (ccRCC), U2OS (osteosarcoma) and H1299 (non-small cell lung cancer) human cancer cell lines – and non-isogenic ccRCC models, using multiple clinical compounds. Mechanistic dissection was performed using immunofluorescence, RT-qPCR, western blotting, DNA fiber assay, transcriptomics, proteomics and DRIP-sequencing to evaluate markers of DNA damage response (DDR), replication stress and cell-autonomous innate immune signaling. Preclinical data were integrated with TCGA tumor data.
Results: Parallel high-throughput drug screens independently identified PARP inhibitors (PARPi) as being synthetic lethal with PBRM1 defects – a cell type-independent effect which was exacerbated by ATR inhibitors (ATRi) and which we revalidated in vitro in isogenic and non-isogenic systems and in vivo in a xenograft model. PBRM1 defects were associated with increased replication fork stress (higher γH2AX and RPA foci levels, decreased replication fork speed and increased ATM checkpoint activation), R-loop accumulation and enhanced genomic instability in vitro; these effects were exacerbated upon PARPi exposure. In patient tumor samples, we also found that PBRM1-mutant cancers possessed a higher mutational load. Finally, we found that ATRi selectively activated the cGAS/STING cytosolic DNA sensing pathway in PBRM1-deficient cells, resulting in increased expression of type I interferon genes.
Conclusion: PBRM1-defective cancer cells present increased replication fork stress, R-loop formation, genome instability and are selectively sensitive to PARPi and ATRi through a synthetic lethal mechanism that is cell type-independent. Our data provide the pre-clinical rationale for assessing PARPi as a monotherapy or in combination with ATRi or immune-modulating agents in molecularly-selected patients with PBRM1-defective cancers.
1057 – Targeting MTHFD2 using first-in-class inhibitors kills haematological and solid cancer through thymineless-induced replication stress
Presenter/AuthorsThomas Helleday. University of Sheffield, Sheffield, United KingdomDisclosures T. Helleday: None.AbstractSummary
Thymidine synthesis pathways are upregulated pathways in cancer. Since the 1940s, targeting nucleotide and folate metabolism to induce thymineless death has remained first-line anti-cancer treatment. Recent discoveries that showing cancer cells have rewired networks and exploit unique enzymes for proliferation, have renewed interest in metabolic pathways. The cancer-specific expression of MTHFD2 has gained wide-spread attention and here we describe an emerging role for MTHFD2 in the DNA damage response (DDR). The folate metabolism enzyme MTHFD2 is one of the most consistently overexpressed metabolic enzymes in cancer and an emerging anticancer target. We show a novel role for MTHFD2 being essential for DNA replication and genomic stability in cancer cells. We describe first-in-class nanomolar MTHFD2 inhibitors (MTHFD2i), with protein co-crystal structures demonstrating binding in the active site of MTHFD2 and engaging with the target in cells and tumours. We show MTHFD2i reduce replication fork speed and induce replication stress, followed by S phase arrest, apoptosis and killing of a range of haematological and solid cancer cells in vitro and in vivo, with a therapeutic window spanning up to four orders of magnitude compared to non-transformed cells. Mechanistically, MTHFD2i prevent thymidine production leading to mis-incorporation of uracil into DNA and replication stress. As MTHFD2 expression is cancer specific there is a potential of MTHFD2i to synergize with other treatments. Here, we show MTHFD2i synergize with dUTPase inhibitors as well as other DDR inhibitors and demonstrate the mechanism of action. These results demonstrate a new link between MTHFD2-dependent cancer metabolism and replication stress that can be exploited therapeutically.
Keywords
MTHFD2, one-carbon metabolism, folate metabolism, DNA replication, replication stress, synthetic lethal, thymineless death, small-molecule inhibitor, DNA damage response
1060 – Genetic and pharmacologic inhibition of Skp2, an E3 ubiquitin ligase and RB1-target, has antitumor activity in RB1-deficient human and mouse small cell lung cancer (SCLC)
Presenter/Authors
Hongling Zhao, Vineeth Sukrithan, Niloy Iqbal, Cari Nicholas, Yingjiao Xue, Joseph Locker, Juntao Zou, Liang Zhu, Edward L. Schwartz. Albert Einstein College of Medicine, Bronx, NY, Albert Einstein College of Medicine, Bronx, NY, Albert Einstein College of Medicine, Bronx, NY, University of Pittsburgh Medical Center, Pittsburgh, PA, Albert Einstein College of Medicine, Bronx, NY
Disclosures
H. Zhao: None. V. Sukrithan: None. N. Iqbal: None. C. Nicholas: None. Y. Xue: None. J. Locker: None. J. Zou: None. L. Zhu: None. E.L. Schwartz: None.
Abstract
The identification of driver mutations and their corresponding targeted drugs has led to significant improvements in the treatment of non-small cell lung cancer (NSCLC) and other solid tumors; however, similar advances have not been made in the treatment of small cell lung cancer (SCLC). Due to their aggressive growth, frequent metastases, and resistance to chemotherapy, the five-year overall survival of SCLC is less than 5%. While SCLC tumors can be sensitive to first-line therapy of cisplatin and etoposide, most patients relapse, often in less than 3 months after initial therapy. Dozens of drugs have been tested clinically in SCLC, including more than 40 agents that have failed in phase III trials.
The near uniform bi-allelic inactivation of the tumor suppressor gene RB1 is a defining feature of SCLC. RB1 is mutated in highly aggressive tumors, including SCLC, where its functional loss, along with that of TP53, is both required and sufficient for tumorigenesis. While it is known that RB1 mutant cells fail to arrest at G1/S in response to checkpoint signals, this information has not led to effective strategies to treat RB1-deficient tumors, and it has been challenging to develop targeted drugs for tumors that are driven by the loss of gene function.
Our group previously identified Skp2, a substrate recruiting subunit of the SCF-Skp2 E3 ubiquitin ligase, as an early repression target of pRb whose knockout blocked tumorigenesis in Rb1-deficient prostate and pituitary tumors. Here we used genetic mouse models to demonstrate that deletion of Skp2 completely blocked the formation of SCLC in Rb1/p53-knockout mice (RP mice). Skp2 KO caused an increased accumulation of the Skp2-degradation target p27, a cyclin-dependent kinase inhibitor, and we confirmed this was the mechanism of protection in the RP-Skp2 KO mice by using the knock-in of a mutant p27 that was unable to bind to Skp2. Building on the observed synthetic lethality between Rb1 and Skp2, we found that small molecules that bind to and/or inhibit Skp2 induced apoptosis and inhibited SCLC cell growth. In a panel of SCLC cell lines, growth inhibition by a Skp2 inhibitor was not correlated with sensitivity/resistance to etoposide. Targeting Skp2 also had in vivo antitumor activity in mouse tumors and human patient-derived xenograft models of SCLC. Using the genetic and pharmacologic approaches, antitumor activity was seen in vivo in established SCLC primary lung tumors, in liver metastases, and in chemotherapy-resistant tumors. The identification and validation of an actionable target downstream of RB1 could have a broad impact on treatment of SCLC and other advanced tumors with mutant RB1, for which there are currently no targeted therapies available.
Live Notes, Real Time Conference Coverage 2020 AACR Virtual Meeting April 27, 2020 Minisymposium on AACR Project Genie & Bioinformatics 4:00 PM – 6:00 PM
April 27, 2020, 4:00 PM – 6:00 PM
Virtual Meeting: All Session Times Are U.S. EDT
Session Type
Virtual Minisymposium
Track(s)
Bioinformatics and Systems Biology
17 Presentations
4:00 PM – 6:00 PM
– Chairperson Gregory J. Riely. Memorial Sloan Kettering Cancer Center, New York, NY
4:00 PM – 4:01 PM
– Introduction Gregory J. Riely. Memorial Sloan Kettering Cancer Center, New York, NY
Precision medicine requires an end-to-end learning healthcare system, wherein the treatment decisions for patients are informed by the prior experiences of similar patients. Oncology is currently leading the way in precision medicine because the genomic and other molecular characteristics of patients and their tumors are routinely collected at scale. A major challenge to realizing the promise of precision medicine is that no single institution is able to sequence and treat sufficient numbers of patients to improve clinical-decision making independently. To overcome this challenge, the AACR launched Project GENIE (Genomics Evidence Neoplasia Information Exchange).
AACR Project GENIE is a publicly accessible international cancer registry of real-world data assembled through data sharing between 19 of the leading cancer centers in the world. Through the efforts of strategic partners Sage Bionetworks (https://sagebionetworks.org) and cBioPortal (www.cbioportal.org), the registry aggregates, harmonizes, and links clinical-grade, next-generation cancer genomic sequencing data with clinical outcomes obtained during routine medical practice from cancer patients treated at these institutions. The consortium and its activities are driven by openness, transparency, and inclusion, ensuring that the project output remains accessible to the global cancer research community for the benefit of all patients.AACR Project GENIE fulfills an unmet need in oncology by providing the statistical power necessary to improve clinical decision-making, particularly in the case of rare cancers and rare variants in common cancers. Additionally, the registry can power novel clinical and translational research.
Because we collect data from nearly every patient sequenced at participating institutions and have committed to sharing only clinical-grade data, the GENIE registry contains enough high-quality data to power decision making on rare cancers or rare variants in common cancers. We see the GENIE data providing another knowledge turn in the virtuous cycle of research, accelerating the pace of drug discovery, improving the clinical trial design, and ultimately benefiting cancer patients globally.
The first set of cancer genomic data aggregated through AACR Project Genomics Evidence Neoplasia Information Exchange (GENIE) was available to the global community in January 2017. The seventh data set, GENIE 7.0-public, was released in January 2020 adding more than 9,000 records to the database. The combined data set now includes nearly 80,000 de-identified genomic records collected from patients who were treated at each of the consortium’s participating institutions, making it among the largest fully public cancer genomic data sets released to date. These data will be released to the public every six months. The public release of the eighth data set, GENIE 8.0-public, will take place in July 2020.
The combined data set now includes data for over 80 major cancer types, including data from greater than 12,500 patients with lung cancer, nearly 11,000 patients with breast cancer, and nearly 8,000 patients with colorectal cancer.
For more details about the data, analyses, and summaries of the data attributes from this release, GENIE 7.0-public, consult the data guide.
Users can access the data directly via cbioportal, or download the data directly from Sage Bionetworks. Users will need to create an account for either site and agree to the terms of access.
For frequently asked questions, visit our FAQ page.
In fall of 2019 AACR announced the Bio Collaborative which collected pan cancer data in conjuction and collaboration and support by a host of big pharma and biotech companies
they have a goal to expand to more than 6 cancer types and more than 50,000 records including smoking habits, lifestyle data etc
They have started with NSCLC have have done mutational analysis on these
included is tumor mutational burden and using cbioportal able to explore genomic data even further
treatment data is included as well
need to collect highly CURATED data with PRISM backbone to get more than outcome data, like progression data
they might look to incorporate digital pathology but they are not there yet; will need good artificial intelligence systems
4:01 PM – 4:15 PM
– Invited Speaker Gregory J. Riely. Memorial Sloan Kettering Cancer Center, New York, NY
4:15 PM – 4:20 PM
– Discussion
4:20 PM – 4:30 PM
1092 – A systematic analysis of BRAF mutations and their sensitivity to different BRAF inhibitors: Zohar Barbash, Dikla Haham, Liat Hafzadi, Ron Zipor, Shaul Barth, Arie Aizenman, Lior Zimmerman, Gabi Tarcic. Novellusdx, Jerusalem, Israel
Abstract: The MAPK-ERK signaling cascade is among the most frequently mutated pathways in human cancer, with the BRAF V600 mutation being the most common alteration. FDA-approved BRAF inhibitors as well as combination therapies of BRAF and MEK inhibitors are available and provide survival benefits to patients with a BRAF V600 mutation in several indications. Yet non-V600 BRAF mutations are found in many cancers and are even more prevalent than V600 mutations in certain tumor types. As the use of NGS profiling in precision oncology is becoming more common, novel alterations in BRAF are being uncovered. This has led to the classification of BRAF mutations, which is dependent on its biochemical properties and affects it sensitivity to inhibitors. Therefore, annotation of these novel variants is crucial for assigning correct treatment. Using a high throughput method for functional annotation of MAPK activity, we profiled 151 different BRAF mutations identified in the AACR Project GENIE dataset, and their response to 4 different BRAF inhibitors- vemurafenib and 3 different exploratory 2nd generation inhibitors. The system is based on rapid synthesis of the mutations and expression of the mutated protein together with fluorescently labeled reporters in a cell-based assay. Our results show that from the 151 different BRAF mutations, ~25% were found to activate the MAPK pathway. All of the class 1 and 2 mutations tested were found to be active, providing positive validation for the method. Additionally, many novel activating mutations were identified, some outside of the known domains. When testing the response of the active mutations to different classes of BRAF inhibitors, we show that while vemurafenib efficiently inhibited V600 mutations, other types of mutations and specifically BRAF fusions were not inhibited by this drug. Alternatively, the second-generation experimental inhibitors were effective against both V600 as well as non-V600 mutations.Using this large-scale approach to characterize BRAF mutations, we were able to functionally annotate the largest number of BRAF mutations to date. Our results show that the number of activating variants is large and that they possess differential sensitivity to different types of direct inhibitors. This data can serve as a basis for rational drug design as well as more accurate treatment options for patients.
Molecular profiling is becoming imperative for successful targeted therapies
500 unique mutations in BRAF so need to use bioinformatic pipeline; start with NGS panels then cluster according to different subtypes or class specific patterns
certain mutation like V600E mutations have distinct clustering in tumor types
25% of mutations occur with other mutations; mutations may not be functional; they used highthruput system to analyze other V600 braf mutations to determine if functional
active yet uncharacterized BRAF mutations seen in a major proportion of human tumors
using genomic drug data found that many inhibitors like verafanib are specific to a specific mutation but other inhibitors that are not specific to a cleft can inhibit other BRAF mutants
40% of 135 mutants were functionally active
USE of Functional Profiling instead of just genomic profiling
Q?: They have already used this platform and analysis for RTKs and other genes as well successfully
Q? how do you deal with co reccuring mutations: platform is able to do RTK plus signaling protiens
4:30 PM – 4:35 PM
– Discussion
4:35 PM – 4:45 PM
1093 – Calibration Tool for Genomic Aggregates (CTGA): A deep learning framework for calibrating somatic mutation profiling data from conventional gene panel data. Jordan Anaya, Craig Cummings, Jocelyn Lee, Alexander Baras. Johns Hopkins Sidney Kimmel Comprehensive Cancer Center, MD, Genentech, Inc., CA, AACR, Philadelphia, PA
Abstract: It has been suggested that aggregate genomic measures such as mutational burden can be associated with response to immunotherapy. Arguably, the gold standard for deriving such aggregate genomic measures (AGMs) would be from exome level sequencing. While many clinical trials run exome level sequencing, the vast majority of routine genomic testing performed today, as seen in AACR Project GENIE, is targeted / gene-panel based sequencing.
Despite the smaller size of these gene panels focused on clinically targetable alterations, it has been shown they can estimate, to some degree, exomic mutational burden; usually by normalizing mutation count by the relevant size of the panels. These smaller gene panels exhibit significant variability both in terms of accuracy relative to exomic measures and in comparison to other gene panels. While many genes are common to the panels in AACR Project GENIE, hundreds are not. These differences in extent of coverage and genomic loci examined can result in biases that may negatively impact panel to panel comparability.
To address these issues we developed a deep learning framework to model exomic AGMs, such as mutational burden, from gene panel data as seen in AACR Project GENIE. This framework can leverage any available sample and variant level information, in which variants are featurized to effectively re-weight their importance when estimating a given AGM, such as mutational burden, through the use of multiple instance learning techniques in this form of weakly supervised data.
Using TCGA data in conjunction with AACR Project GENIE gene panel definitions, as a proof of concept, we first applied this framework to learn expected variant features such as codons and genomic position from mutational data (greater than 99.9% accuracy observed). Having established the validity of the approach, we then applied this framework to somatic mutation profiling data in which we show that data from gene panels can be calibrated to exomic TMB and thereby improve panel to panel compatibility. We observed approximately 25% improvements in mean squared error and R-squared metrics when using our framework over conventional approaches to estimate TMB from gene panel data across the 9 tumors types examined (spanning melanoma, lung cancer, colon cancer, and others). This work highlights the application of sophisticated machine learning approaches towards the development of needed calibration techniques across seemingly disparate gene panel assays used clinically today.
4:45 PM – 4:50 PM
– Discussion
4:50 PM – 5:00 PM
1094 – Genetic determinants of EGFR-driven lung cancer growth and therapeutic response in vivoGiorgia Foggetti, Chuan Li, Hongchen Cai, Wen-Yang Lin, Deborah Ayeni, Katherine Hastings, Laura Andrejka, Dylan Maghini, Robert Homer, Dmitri A. Petrov, Monte M. Winslow, Katerina Politi. Yale School of Medicine, New Haven, CT, Stanford University School of Medicine, Stanford, CA, Stanford University School of Medicine, Stanford, CA, Yale School of Medicine, New Haven, CT, Stanford University School of Medicine, Stanford, CA, Yale School of Medicine, New Haven, CT
5:00 PM – 5:05 PM
– Discussion
5:05 PM – 5:15 PM
1095 – Comprehensive pan-cancer analyses of RAS genomic diversityRobert Scharpf, Gregory Riely, Mark Awad, Michele Lenoue-Newton, Biagio Ricciuti, Julia Rudolph, Leon Raskin, Andrew Park, Jocelyn Lee, Christine Lovly, Valsamo Anagnostou. Johns Hopkins Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD, Memorial Sloan Kettering Cancer Center, New York, NY, Dana-Farber Cancer Institute, Boston, MA, Vanderbilt-Ingram Cancer Center, Nashville, TN, Amgen, Inc., Thousand Oaks, CA, AACR, Philadelphia, PA
5:15 PM – 5:20 PM
– Discussion
5:20 PM – 5:30 PM
1096 – Harmonization standards from the Variant Interpretation for Cancer Consortium. Alex H. Wagner, Reece K. Hart, Larry Babb, Robert R. Freimuth, Adam Coffman, Yonghao Liang, Beth Pitel, Angshumoy Roy, Matthew Brush, Jennifer Lee, Anna Lu, Thomas Coard, Shruti Rao, Deborah Ritter, Brian Walsh, Susan Mockus, Peter Horak, Ian King, Dmitriy Sonkin, Subha Madhavan, Gordana Raca, Debyani Chakravarty, Malachi Griffith, Obi L. Griffith. Washington University School of Medicine, Saint Louis, MO, Reece Hart Consulting, CA, Broad Institute, Boston, MA, Mayo Clinic, Rochester, MN, Washington University School of Medicine, Saint Louis, MO, Washington University School of Medicine, Saint Louis, MO, Baylor College of Medicine, Houston, TX, Oregon Health and Science University, Portland, OR, National Cancer Institute, Bethesda, MD, Georgetown University, Washington, DC, The Jackson Laboratory for Genomic Medicine, Farmington, CT, National Center for Tumor Diseases, Heidelberg, Germany, University of Toronto, Toronto, ON, Canada, University of Southern California, Los Angeles, CA, Memorial Sloan Kettering Cancer Center, New York, NY
Abstract: The use of clinical gene sequencing is now commonplace, and genome analysts and molecular pathologists are often tasked with the labor-intensive process of interpreting the clinical significance of large numbers of tumor variants. Numerous independent knowledge bases have been constructed to alleviate this manual burden, however these knowledgebases are non-interoperable. As a result, the analyst is left with a difficult tradeoff: for each knowledgebase used the analyst must understand the nuances particular to that resource and integrate its evidence accordingly when generating the clinical report, but for each knowledgebase omitted there is increased potential for missed findings of clinical significance.The Variant Interpretation for Cancer Consortium (VICC; cancervariants.org) was formed as a driver project of the Global Alliance for Genomics and Health (GA4GH; ga4gh.org) to address this concern. VICC members include representatives from several major somatic interpretation knowledgebases including CIViC, OncoKB, Jax-CKB, the Weill Cornell PMKB, the IRB-Barcelona Cancer Biomarkers Database, and others. Previously, the VICC built and reported on a harmonized meta-knowledgebase of 19,551 biomarker associations of harmonized variants, diseases, drugs, and evidence across the constituent resources.In that study, we analyzed the frequency with which the tumor samples from the AACR Project GENIE cohort would match to harmonized associations. Variant matches increased dramatically from 57% to 86% when broader matching to regions describing categorical variants were allowed. Unlike precise sequence variants with specified alternate alleles, categorical variants describe a collection of potential variants with a common feature, such as “V600” (non-valine alleles at the 600 residue), “Exon 20 mutations” (all non-silent mutations in exon 20), or “Gain-of-function” (hypermorphic alterations that activate or amplify gene activity). However, matching observed sequence variants to categorical variants is challenging, as the latter are typically only described as unstructured text. Here we describe the expressive and computational GA4GH Variation Representation specification (vr-spec.readthedocs.io), which we co-developed as members of the GA4GH Genomic Knowledge Standards work stream. This specification provides a schema for common, precise forms of variation (e.g. SNVs and Indels) and the method for computing identifiers from these objects. We highlight key aspects of the specification and our work to apply it to the characterization of categorical variation, showcasing the variant terminology and classification tools developed by the VICC to support this effort. These standards and tools are free, open-source, and extensible, overcoming barriers to standardized variant knowledge sharing and search.
store information from different databases by curating them and classifying them then harmonizing them into values
harmonize each variant across their knowledgebase; at any level of evidence
had 29% of patients variants that matched when compare across many knowledgebase databases versus only 13% when using individual databases
they are also trying to curate the database so a variant will have one code instead of various refseq codes or protein codes
VIC is an open consortium
5:30 PM – 5:35 PM
– Discussion
5:35 PM – 5:45 PM
1097 – FGFR2 in-frame indels: A novel targetable alteration in intrahepatic cholangiocarcinoma. Yvonne Y. Li, James M. Cleary, Srivatsan Raghavan, Liam F. Spurr, Qibiao Wu, Lei Shi, Lauren K. Brais, Maureen Loftus, Lipika Goyal, Anuj K. Patel, Atul B. Shinagare, Thomas E. Clancy, Geoffrey Shapiro, Ethan Cerami, William R. Sellers, William C. Hahn, Matthew Meyerson, Nabeel Bardeesy, Andrew D. Cherniack, Brian M. Wolpin. Dana-Farber Cancer Institute, Boston, MA, Dana-Farber Cancer Institute, Boston, MA, Massachusetts General Hospital, Boston, MA, Brigham and Women’s Hospital, Boston, MA, Dana-Farber Cancer Institute, Boston, MA, Dana-Farber Cancer Institute, Boston, MA, Broad Institute of MIT and Harvard, Cambridge, MA, Massachusetts General Hospital, Boston, MA
5:45 PM – 5:50 PM
– Discussion
5:50 PM – 6:00 PM
– Closing RemarksGregory J. Riely. Memorial Sloan Kettering Cancer Center, New York, NY
SESSION VSY.DDT01 – New Drugs on the Horizon: Part 1
April 27, 2020, 4:50 PM – 6:05 PM
Virtual Meeting: All Session Times Are U.S. EDT
Session Type
Virtual Symposium
Track(s)
Experimental and Molecular Therapeutics,Drug Development
10 Presentations
4:50 PM – 6:00 PM
– CochairAndrew J. Phillips. C4 Therapeutics, Watertown, MA
4:50 PM – 4:54 PM
– IntroductionAndrew J. Phillips. C4 Therapeutics, Watertown, MA
4:54 PM – 5:14 PM
DDT01-01 – A first-in-class Menin-MLL1 antagonist for the treatment of MLL-r and NPM1 mutant leukemias Jerry McGeehan. Syndax Pharmaceuticals, Inc., Waltham, MA
Their inhibitor binds to C terminus of Menin MLL1 which is required for AML progression
MLL-4 is from a translocation causing a fusion protein; the inhibitor block leukemic transcription program
anti transcription program when Menin inhibitor is used; displaces Menin from chromatin
worked in tumor models
their inhibitors have good antiproliferative activity seems has good bio-availability in rat and dog
they have active QT signal (cardiac tox) screen program in their clinical studies
initial pre phase1 have not found the max effective dose
not a complete response so may have to look at combination
5:14 PM – 5:17 PM
– Discussion
5:17 PM – 5:37 PM
DDT01-02 – BAY 2416964: The first Aryl Hydrocarbon Receptor (AhR) inhibitor to enter phase I clinical development as a novel cancer immunotherapy. Ilona Gutcher, Christina Kober, Julian Röwe, Ulrike Roehn, Lars Roese, Florian Prinz, Detlef Stoeckigt, Benjamin Bader, Matyas Gorjanacz, Rafael Carretero, Norbert Schmees, Horst Irlbacher, Helge Roider, Katharina Sahm, Hilmar Weinmann, Ingo V. Hartung, Bertolt Kreft, Rienk Offringa, Michael Platten. Bayer AG, Berlin, Germany, Bayer AG, Germany, DKFZ, Heidelberg, Germany
has a more proinflammatory effect in vivo than other I/O inhibitors
rescues TNF alpha immunomodulation
further increases IL2 and IFN gamma when combined with I/O inhibitor so by a different mechanism
looking to use in NSCLC
prelim tox looks fine
5:37 PM – 5:40 PM
– Discussion
5:40 PM – 6:00 PM
DDT01-03 – IPN60090: A potent and selective inhibitor of glutaminase being developed for KEAP1/NFE2L2 mutant NSCLC and ASNS-low HGSOC patients. Jeffrey J. Kovacs. UT MD Anderson Cancer Center, Houston, TX
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
SESSION VMS.MCB01.01 – Emerging Signaling Vulnerabilities in Cancer
April 27, 2020, 11:45 AM – 1:30 PM
Virtual Meeting: All Session Times Are U.S. EDT
DESCRIPTION
All session times are U.S. Eastern Daylight Time (EDT). Access to AACR Virtual Annual Meeting I sessions are free with registration. Register now at http://www.aacr.org/virtualam2020
Session Type
Virtual Minisymposium
Track(s)
Molecular and Cellular Biology/Genetics
16 Presentations
11:45 AM – 1:30 PM
– Chairperson
J. Silvio Gutkind. UCSD Moores Cancer Center, La Jolla, CA
11:45 AM – 1:30 PM
– Chairperson
in 80’s and 90’s signaling focused on defects and also oncogene addiction. Now the field is switching to finding vulnerabilities in signaling cascades in cancer
Adrienne D. Cox. University of North Carolina at Chapel Hill, Chapel Hill, NC
11:45 AM – 11:55 AM
– Introduction
J. Silvio Gutkind. UCSD Moores Cancer Center, La Jolla, CA
11:55 AM – 12:05 PM
1085 – Interrogating the RAS interactome identifies EFR3A as a novel enhancer of RAS oncogenesis
Hema Adhikari, Walaa Kattan, John F. Hancock, Christopher M. Counter. Duke University, Durham, NC, University of Texas MD Anderson Cancer Center, Houston, TX
Abstract: Activating mutations in one of the three RAS genes (HRAS, NRAS, and KRAS) are detected in as much as a third of all human cancers. As oncogenic RAS mediates it tumorigenic signaling through protein-protein interactions primarily at the plasma membrane, we sought to document the protein networks engaged by each RAS isoform to identify new vulnerabilities for future therapeutic development. To this end, we determined interactomes of oncogenic HRAS, NRAS, and KRAS by BirA-mediated proximity labeling. This analysis identified roughly ** proteins shared among multiple interactomes, as well as a smaller subset unique to a single RAS oncoprotein. To identify those interactome components promoting RAS oncogenesis, we created and screened sgRNA library targeting the interactomes for genes modifying oncogenic HRAS-, NRAS-, or KRAS-mediated transformation. This analysis identified the protein EFR3A as not only a common component of all three RAS interactomes, but when inactivated, uniformly reduced the growth of cells transformed by any of the three RAS isoforms. EFR3A recruits a complex containing the druggable phosphatidylinositol (Ptdlns) 4 kinase alpha (PI4KA) to the plasma membrane to generate the Ptdlns species PI4P. We show that EFR3A sgRNA reduced multiple RAS effector signaling pathways, suggesting that EFR3A acts at the level of the oncoprotein itself. As lipids play a critical role in the membrane localization of RAS, we tested and found that EFR3A sgRNA reduced not only the occupancy of RAS at the plasma membrane, but also the nanoclustering necessary for signaling. Furthermore, the loss of oncogenic RAS signaling induced by EFR3A sgRNA was rescued by targeting PI4K to the plasma membrane. Taken together, these data support a model whereby EFR3A recruits PI4K to oncogenic RAS to promote plasma membrane localization and nonclustering, and in turn, signaling and transformation. To investigate the therapeutic potential of this new RAS enhancer, we show that EFR3A sgRNA reduced oncogenic KRAS signaling and transformed growth in a panel of pancreatic ductal adenocarcinoma (PDAC) cell lines. Encouraged by these results we are exploring whether genetically inactivating the kinase activity of PI4KA inhibits oncogenic signaling and transformation in PDAC cell lines. If true, pharmacologically targeting PI4K may hold promise as a way to enhance the anti-neoplastic activity of drugs targeting oncogenic RAS or its effectors.
different isoforms of ras mutations exist differentially in various tumor types e.g. nras vs kras
the C terminal end serve as hotspots of mutations and probably isoform specific functions
they determined the interactomes of nras and kras and determined how many candidates are ras specific
they overlayed results from proteomic and CRSPR screen; EFR3a was a potential target that stuck out
using TCGA patients with higher EFR3a had poorer prognosis
EFR3a promotes Ras signaling; and required for RAS driven tumor growth (in RAS addicted tumors?)
EGFR3a promotes clustering of oncogenic RAS at plasma membrane
12:05 PM – 12:10 PM
– Discussion
12:10 PM – 12:20 PM
1086 – Downstream kinase signaling is dictated by specific KRAS mutations; Konstantin Budagyan, Jonathan Chernoff. Drexel University College of Medicine, Philadelphia, PA, Fox Chase Cancer Center, Philadelphia, PA @FoxChaseCancer
Abstract: Oncogenic KRAS mutations are common in colorectal cancer (CRC), found in ~50% of tumors, and are associated with poor prognosis and resistance to therapy. There is substantial diversity of KRAS alleles observed in CRC. Importantly, emerging clinical and experimental analysis of relatively common KRAS mutations at amino acids G12, G13, A146, and Q61 suggest that each mutation differently influences the clinical properties of a disease and response to therapy. For example, KRAS G12 mutations confer resistance to EGFR-targeted therapy, while G13D mutations do not. Although there is clinical evidence to suggest biological differences between mutant KRAS alleles, it is not yet known what drives these differences and whether they can be exploited for allele-specific therapy. We hypothesized that different KRAS mutants elicit variable alterations in downstream signaling pathways. To investigate this hypothesis, we created a novel system by which we can model KRAS mutants in isogenic mouse colon epithelial cell lines. To generate the cell lines, we developed an assay using fluorescent co-selection for CRISPR-driven genome editing. This assay involves simultaneous introduction of single-guide RNAs (sgRNAs) to two different endogenous loci resulting in double-editing events. We first introduced Cas9 and blue fluorescent protein (BFP) into mouse colon epithelial cell line containing heterozygous KRAS G12D mutation. We then used sgRNAs targeting BFP and the mutant G12D KRAS allele along with homology-directed repair (HDR) templates for a GFP gene and a KRAS mutant allele of our choice. Cells that successfully undergo HDR are GFP-positive and contain the desired KRAS mutation. Therefore, selection for GFP-positive cells allows us to identify those with phenotypically silent KRAS edits. Ultimately, this method allows us to toggle between different mutant alleles while preserving the wild-type allele, all in an isogenic background. Using this method, we have generated cell lines with endogenous heterozygous KRAS mutations commonly seen in CRC (G12D, G12V, G12C, G12R, G13D). In order to elucidate cellular signaling pathway differences between the KRAS mutants, we screened the mutated cell lines using a small-molecule library of ~160 protein kinase inhibitors. We found that there are mutation-specific differences in drug sensitivity profiles. These observations suggest that KRAS mutants drive specific cellular signaling pathways, and that further exploration of these pathways may prove to be valuable for identification of novel therapeutic opportunities in CRC.
Flourescent coselection of KRAS edits by CRSPR screen in a colorectal cancer line; a cell that is competent to undergo HR can undergo combination multiple KRAS
target only mutant allele while leaving wild type intact;
it was KRAS editing event in APC +/- mouse cell line
this enabled a screen for kinase inhibitors that decreased tumor growth in isogenic cell lines; PKC alpha and beta 1 inhibitors, also CDK4 inhibitors inhibited cell growth
questions about heterogeneity in KRAS clones; they looked at off target guides and looked at effects in screens; then they used top two clones that did not have off target; questions about 3D culture- they have not done that; Question ? dependency on AKT activity? perhaps the G12E has different downstream effectors
12:20 PM – 12:25 PM
– Discussion
12:25 PM – 12:35 PM
1087 – NF1 regulates the RAS-related GTPases, RRAS and RRAS2, independent of RAS activity; Jillian M. Silva, Lizzeth Canche, Frank McCormick. University of California, San Francisco, San Francisco, CA @UCSFMedicine
Abstract: Neurofibromin, which is encoded by the neurofibromatosis type 1 (NF1) gene, is a tumor suppressor that acts as a RAS-GTPase activating protein (RAS-GAP) to stimulate the intrinsic GTPase activity of RAS as well as the closely related RAS subfamily members, RRAS, RRAS2, and MRAS. This results in the conversion of the active GTP-bound form of RAS into the inactive GDP-bound state leading to the downregulation of several RAS downstream effector pathways, most notably MAPK signaling. While the region of NF1 that regulates RAS activity represents only a small fraction of the entire protein, a large extent of the NF1 structural domains and their corresponding mechanistic functions remain uncharacterized despite the fact there is a high frequency of NF1 mutations in several different types of cancer. Thus, we wanted to elucidate the underlying biochemical and signaling functions of NF1 that are unrelated to the regulation of RAS and how loss of these functions contributes to the pathogenesis of cancer. To accomplish this objective, we used CRISPR-Cas9 methods to knockout NF1 in an isogenic “RASless” MEF model system, which is devoid of the major oncogenic RAS isoforms (HRAS, KRAS, and NRAS) and reconstituted with the KRAS4b wild-type or mutant KRASG12C or KRASG12D isoform. Loss of NF1 led to elevated RAS-GTP levels, however, this increase was not as profound as the levels in KRAS-mutated cells or provided a proliferative advantage. Although ablation of NF1 resulted in sustained activation of MAPK signaling, it also unexpectedly, resulted in a robust increase in AKT phosphorylation compared to KRAS-mutated cells. Surprisingly, loss of NF1 in KRAS4b wild-type and KRAS-mutated cells potently suppressed the RAS-related GTPases, RRAS and RRAS2, with modest effects on MRAS, at both the transcript and protein levels. A Clariom™D transcriptome microarray analysis revealed a significant downregulation in the NF-κB target genes, insulin-like growth factor binding protein 2 (IGFBP2), argininosuccinate synthetase 1 (ASS1), and DUSP1, in both the NF1 knockout KRAS4b wild-type and KRAS-mutated cells. Moreover, NF1Null melanoma cells also displayed a potent suppression of RRAS and RRAS2 as well as these NF-κB transcription factors. Since RRAS and RRAS2 both contain the same NF-κB transcription factor binding sites, we hypothesize that IGFBP2, ASS1, and/or DUSP1 may contribute to the NF1-mediated regulation of these RAS-related GTPases. More importantly, this study provides the first evidence of at least one novel RAS-independent function of NF1 to regulate the RAS-related subfamily members, RRAS and RRAS2, in a manner exclusive of its RAS-GTPase activity and this may provide insight into new potential biomarkers and molecular targets for treating patients with mutations in NF1.
NF1 and SPRED work together to signal from RTK cKIT through RAS
NF1 knockout cells had higher KRAS and had increased cell proliferation
NF1 -/- or SPRED loss had increased ERK phosphorylation and some increase in AKT activity compared to parental cells
they used isogenic cell lines devoid of all RAS isoforms and then reconstituted with specific RAS WT or mutants
NF1 and SPRED KO both reduce RRAS expression; in an AKT independent mannner
NF1 SPRED KO cells have almost no IGFBP2 protein expression and SNAIL so maybe affecting EMT?
this effect is independent of its RAS GTPAse activity (noncanonical)
12:35 PM – 12:40 PM
– Discussion
12:40 PM – 12:50 PM
1088 – Elucidating the regulation of delayed-early gene targets of sustained MAPK signaling; Kali J. Dale, Martin McMahon. University of Utah, Salt Lake City, UT, Huntsman Cancer Institute, Salt Lake City, UT
Abstract:RAS and its downstream effector, BRAF, are commonly mutated proto-oncogenes in many types of human cancer. Mutationally activated RAS or BRAF signal through the MEK→ERK MAP kinase (MAPK) pathway to regulate key cancer cell hallmarks such as cell division cycle progression, reduced programmed cell death, and enhanced cell motility. Amongst the list of RAS/RAF-regulated genes are those encoding integrins, alpha-beta heterodimeric transmembrane proteins that regulate cell adhesion to the extracellular matrix. Altered integrin expression has been linked to the acquisition of more aggressive behavior by melanoma, lung, and breast cancer cells leading to diminished survival of cancer patients. We have previously documented the ability of the RAS-activated MAPK pathway to induce the expression of ITGB3 encoding integrin β3 in several different cell types. RAS/RAF-mediated induction of ITGB3 mRNA requires sustained, high-level activation of RAF→MEK→ERK signaling mediated by oncogene activation and is classified as “delayed-early”, in that it is sensitive to the protein synthesis inhibitor cycloheximide. However, to date, the regulatory mechanisms that allow for induced ITGB3 downstream of sustained, high-level activation of MAPK signaling remains obscure. We have identified over 300 DEGs, including those expressing additional cell surface proteins, that display similar regulatory characteristics as ITGB3. We use integrin β3 as a model to test our hypothesis that there is a different mechanism of regulation for delayed-early genes (DEG) compared to the canonical regulation of Immediate-Early genes. There are three regions in the chromatin upstream of the ITGB3 that become more accessible during RAF activation. We are relating the chromatin changes seen during RAF activation to active enhancer histone marks. To elucidate the essential genes of this regulation process, we are employing the use of a genome-wide CRISPR knockout screen. The work presented from this abstract will help elucidate the regulatory properties of oncogenic progression in BRAF mutated cancers that could lead to the identification of biomarkers.
12:50 PM – 12:55 PM
– Discussion
12:55 PM – 1:05 PM
1090 – Regulation of PTEN translation by PI3K signaling maintains pathway homeostasis
Radha Mukherjee, Kiran Gireesan Vanaja, Jacob A. Boyer, Juan Qiu, Xiaoping Chen, Elisa De Stanchina, Sarat Chandarlapaty, Andre Levchenko, Neal Rosen. Memorial Sloan Kettering Cancer Center, New York, NY, Yale University, West Haven, CT, Memorial Sloan Kettering Cancer Center, New York, NY, Memorial Sloan Kettering Cancer Center, New York, NY @sloan_kettering
Abstract: The PI3K pathway is a key regulator of metabolism, cell proliferation and migration and some of its components (e.g. PIK3CA and PTEN) are frequently altered in cancer by genetic events that deregulate its output. However, PI3K signaling is not usually the primary driver of these tumors and inhibitors of components of the pathway have only modest antitumor effects. We now show that both physiologic and oncogenic activation of the PI3K signaling by growth factors and an activating hotspot PIK3CA mutation respectively, cause an increase in the expression of the lipid phosphatase PTEN, thus limiting the duration of the signal and the output of the pathway in tumors. Pharmacologic and physiologic inhibition of the pathway by HER2/PI3K/AKT/mTOR inhibitors and nutrient starvation respectively reduce PTEN, thus buffering the effects of inhibition and contributing to the rebound in pathway activity that occurs in tumors. This regulation is found to be a feature of multiple types of cancer, non-cancer cell line and PDX models thereby highlighting its role as a key conserved feedback loop within the PI3K signaling network, both in vitro and in vivo. Regulation of expression is due to mTOR/4EBP1 dependent control of PTEN translation and is lost when 4EBP1 is knocked out. Translational regulation of PTEN is therefore a major homeostatic regulator of physiologic PI3K signaling and plays a role in reducing the output of oncogenic mutants that deregulate the pathway and the antitumor activity of PI3K pathway inhibitors.
mTOR can be a potent regulator of PTEN and therefore a major issue when developing PI3K inhibitors
1:05 PM – 1:10 PM
– Discussion
1:10 PM – 1:20 PM
1091 – BI-3406 and BI 1701963: Potent and selective SOS1::KRAS inhibitors induce regressions in combination with MEK inhibitors or irinotecan
Daniel Gerlach, Michael Gmachl, Juergen Ramharter, Jessica Teh, Szu-Chin Fu, Francesca Trapani, Dirk Kessler, Klaus Rumpel, Dana-Adriana Botesteanu, Peter Ettmayer, Heribert Arnhof, Thomas Gerstberger, Christiane Kofink, Tobias Wunberg, Christopher P. Vellano, Timothy P. Heffernan, Joseph R. Marszalek, Mark Pearson, Darryl B. McConnell, Norbert Kraut, Marco H. Hofmann. Boehringer Ingelheim RCV GmbH & Co KG, Vienna, Austria, The University of Texas MD Anderson Cancer Center, Houston, TX, The University of Texas MD Anderson Cancer Center, Houston, TX, Boehringer Ingelheim RCV GmbH & Co KG, Vienna, Austria
there is rational for developing an SOS1 inhibitor (GEF); BI3406 shows better PK and PD as a candidate
most sensitive cell lines to inhibitor carry KRAS mutation; NRAS or BRAF mutations are not sensititve
KRAS mutation defines sensitivity so they created KRAS mut isogenic cell lines
found best to co inhibit SOS and MEK as observed plasticity with only SOS
dual combination in lung NSCLC pancreatic showed enhanced efficacy compared to monotherapy
SOS1 inhibition plus irinotecan enhances DNA double strand breaks; no increased DNA damage in normal stroma but preferentially in tumor cells
these SOS1 had broad activity against KRAS mutant models;
Live Notes, Real Time Conference Coverage 2020 AACR Virtual Meeting April 27, 2020 Opening Remarks and Clinical Session 11:45am-1:15pm Advances in Cancer Drug Discovery
SESSION VMS.CH01.01 – Advances in Cancer Drug Design and Discovery
April 27, 2020, 11:45 AM – 1:15 PM
Virtual Meeting: All Session Times Are U.S. EDT
DESCRIPTIONAll session times are U.S. Eastern Daylight Time (EDT).
Session Type
Virtual Minisymposium
Track(s)
Cancer Chemistry
14 Presentations
11:45 AM – 11:45 AM
– ChairpersonZoran Rankovic. St. Jude Children’s Research Hospital, Memphis, TN
11:45 AM – 11:45 AM
– ChairpersonChristopher G. Nasveschuk. C4 Therapeutics, Watertown, MA
11:45 AM – 11:50 AM
– IntroductionZoran Rankovic. St. Jude Children’s Research Hospital, Memphis, TN
11:50 AM – 12:00 PM
1036 – Discovery of a highly potent, efficacious and orally active small-molecule inhibitor of embryonic ectoderm development (EED)Changwei Wang, Rohan Kalyan Rej, Jianfeng Lu, Mi Wang, Kaitlin P. Harvey, Chao-Yie Yang, Ester Fernandez-Salas, Jeanne Stuckey, Elyse Petrunak, Caroline Foster, Yunlong Zhou, Rubin Zhou, Guozhi Tang, Jianyong Chen, Shaomeng Wang. Rogel Cancer Center and Departments of Internal Medicine, Pharmacology, and Medicinal Chemistry, Life Sciences Institute, University of Michigan, Ann Arbor, MI, Ascentage Pharma Group, Taizhou, Jiangsu, China
12:00 PM – 12:05 PM
– Discussion
12:05 PM – 12:15 PM
1037 – Orally available small molecule CD73 inhibitor reverses immunosuppression through blocking of adenosine productionXiaohui Du, Brian Blank, Brenda Chan, Xi Chen, Yuping Chen, Frank Duong, Lori Friedman, Tom Huang, Melissa R. Junttila, Wayne Kong, Todd Metzger, Jared Moore, Daqing Sun, Jessica Sun, Dena Sutimantanapi, Natalie Yuen, Tatiana Zavorotinskaya. ORIC Pharmaceuticals, South San Francisco, CA, ORIC Pharmaceuticals, South San Francisco, CA, ORIC Pharmaceuticals, South San Francisco, CA, ORIC Pharmaceuticals, South San Francisco, CA
12:15 PM – 12:20 PM
– Discussion
12:20 PM – 12:30 PM
1038 – A potent and selective PARP14 inhibitor decreases pro-tumor macrophage function and elicits inflammatory responses in tumor explantsLaurie Schenkel, Jennifer Molina, Kerren Swinger, Ryan Abo, Danielle Blackwell, Anne Cheung, William Church, Kristy Kuplast-Barr, Alvin Lu, Elena Minissale, Mario Niepel, Melissa Vasbinder, Tim Wigle, Victoria Richon, Heike Keilhack, Kevin Kuntz. Ribon Therapeutics, Cambridge, MA
12:30 PM – 12:35 PM
– Discussion
12:35 PM – 12:45 PM
1039 – Fragment-based drug discovery to identify small molecule allosteric inhibitors of SHP2. Philip J. Day, Valerio Berdini, Juan Castro, Gianni Chessari, Thomas G. Davies, James E. H. Day, Satoshi Fukaya, Chris Hamlett, Keisha Hearn, Steve Hiscock, Rhian Holvey, Satoru Ito, Yasuo Kodama, Kenichi Matsuo, Yoko Nakatsuru, Nick Palmer, Amanda Price, Tadashi Shimamura, Jeffrey D. St. Denis, Nicola G. Wallis, Glyn Williams, Christopher N. Johnson. Astex Pharmaceuticals, Inc., Cambridge, United Kingdom, Taiho Pharmaceutical Co., Ltd, Tsukuba, Japan
Abstract: The ubiquitously expressed protein tyrosine phosphatase SHP2 is required for signalling downstream of receptor tyrosine kinases (RTKs) and plays a role in regulating many cellular processes. Recent advances have shown that genetic knockdown and pharmacological inhibition of SHP2 suppresses RAS/MAPK signalling and inhibits proliferation of RTK-driven cancer cell lines. SHP2 is now understood to act upstream of RAS and plays a role in KRAS-driven cancers, an area of research which is rapidly growing. Considering that RTK deregulation often leads to a wide range of cancers and the newly appreciated role of SHP2 in KRAS-driven cancers, SHP2 inhibitors are therefore a promising therapeutic approach.
SHP2 contains two N-terminal tandem SH2 domains (N-SH2, C-SH2), a catalytic phosphatase domain and a C-terminal tail. SHP2 switches between “open” active and “closed” inactive forms due to autoinhibitory interactions between the N-SH2 domain and the phosphatase domain. Historically, phosphatases were deemed undruggable as there had been no advancements with active site inhibitors. We hypothesised that fragment screening would be highly applicable and amenable to this target to enable alternative means of inhibition through identification of allosteric binding sites. Here we describe the first reported fragment screen against SHP2.
Using our fragment-based PyramidTM approach, screening was carried out on two constructs of SHP2; a closed autoinhibited C-terminal truncated form (phosphatase and both SH2 domains), as well as the phosphatase-only domain. A combination of screening methods such as X-ray crystallography and NMR were employed to identify fragment hits at multiple sites on SHP2, including the tunnel-like allosteric site reported by Chen et al, 2016. Initial fragment hits had affinities for SHP2 in the range of 1mM as measured by ITC. Binding of these hits was improved using structure-guided design to generate compounds which inhibit SHP2 phosphatase activity and are promising starting points for further optimization.
anti estrogen receptor therapy: ER degraders is one class
AZ9833 enhances degradation of ER alpha
worked in preclinical mouse model (however very specific)
PK parameters were good for orally available in rodents; also in vitro and in vivo correlation correlated in rats but not in dogs so they were not sure if good to go in humans
they were below Km in rats but already at saturated in dogs, dogs were high clearance
predicted human bioavailability at 40%
12:45 PM – 12:50 PM
– Discussion
12:50 PM – 1:00 PM
1042 – Preclinical pharmacokinetic and metabolic characterization of the next generation oral SERD AZD9833Eric T. Gangl, Roshini Markandu, Pradeep Sharma, Andy Sykes, Petar Pop-Damkov, Pablo Morentin Gutierrez, James S. Scott, Dermot F. McGinnity, Adrian J. Fretland, Teresa Klinowska. AstraZeneca, Waltham, MA
1:00 PM – 1:05 PM
– Discussion
1:05 PM – 1:15 PM
– Closing RemarksChristopher G. Nasveschuk. MA
Dr. Mardis is the Robert E. and Louise F. Dunn Distinguished Professor of Medicine @GenomeInstitute at Washington University of St. Louis School of Medicine.
Opening remarks: Dr. Mardis gave her welcome from her office. She expressed many thanks to healthcare workers and the hard work of scientists and researchers. She also expressed some regret for the many scientists who had wonderful research to present and how hard it was to make the decision to go virtual however she feels there now more than ever still needs a venue to discuss scientific and clinical findings. Some of the initiatives that she has had the opportunity to engage in the areas of groundbreaking discoveries and clinical trials. 606,000 lives will be lost in US this year from cancer. AACR is being vigilant as also an advocacy platform and public policy platform in Congress and Washington. The AACR has been at the front of public policy on electronic cigarettes. Blood Cancer Discovery is their newest journal. They are going to host joint conferences with engineers, mathematicians and physicists to discuss how they can help to transform oncology. Cancer Health Disparity Annual Conference is one of the fastest growing conferences. They will release a report later this year about the scope of the problem and policy steps needed to alleviate these disparities. Lack of racial and ethnic minorities in cancer research had been identified an issue and the AACR is actively working to reduce the disparities within the ranks of cancer researchers. Special thanks to Dr. Margaret Foti for making the AACR the amazing organization it is.
9:15 AM – 9:30 AM- AACR Annual Meeting Program Chair: Review of Program for AACR Virtual Annual Meeting Antoni Ribas. UCLA Medical Center, Los Angeles, CA
Antoni Ribas, MD PhD is Professor, Medicine, Surgery, Molecular and Medical Pharmacology; Director, Parker Institute for Cancer Immunotherapy Center at UCLA; Director, UCLA Jonsson Comprehensive Cancer Center Tumor Immunology Program aribas@mednet.ucla.edu
The AACR felt it was important to keep the discourse in the cancer research field as the Annual AACR meeting is the major way scientists and clinicians discuss the latest and most pertinent results. A three day virtual meeting June 22-24 will focus more on the translational and basic research while this meeting is more focused on clinical trials. There will be educational programs during the June virtual meeting. The COVID in Cancer part of this virtual meeting was put in specially for this meeting and there will be a special meeting on this in July. They have created an AACR COVID task force. The AACR has just asked Congress and NIH to extend the grants due to the COVID induced shutdown of many labs.
9:30 Open Clinical Plenary Session (there are 17 sessions today but will only cover a few of these)
9:30 AM – 9:31 AM
– Chairperson Nilofer S. Azad. Johns Hopkins Sidney Kimmel Comp. Cancer Center, Baltimore, MD @noza512
9:30 AM – 9:31 AM
– Chairperson Manuel Hidalgo. Weill Cornell Medicine, New York, NY
9:30 AM – 9:35 AM
– Introduction Nilofer S. Azad. Johns Hopkins Sidney Kimmel Comp. Cancer Center, Baltimore, MD
9:35 AM – 9:45 AM
CT011 – Evaluation of durvalumab in combination with olaparib and paclitaxel in high-risk HER2 negative stage II/III breast cancer: Results from the I-SPY 2 TRIAL Lajos Pusztai, et al
AbstractBackground: I-SPY2 is a multicenter, phase 2 trial using response-adaptive randomization within molecular subtypes defined by receptor status and MammaPrint risk to evaluate novel agents as neoadjuvant therapy for breast cancer. The primary endpoint is pathologic complete response (pCR, ypT0/is ypN0)). DNA repair deficiency in cancer cells can lead to immunogenic neoantigens, activation of the STING pathway, and PARP inhibition can also upregulate PD-L1 expression. Based on these rationales we tested the combination of durvalumab (anti-PDL1), olaparib (PARP inhibitor) and paclitaxel in I-SPY2. Methods: Women with tumors ≥ 2.5 cm were eligible for screening. Only HER2 negative (HER2-) patients were eligible for this treatment, hormone receptor positive (HR+) patients had to have MammaPrint high molecular profile. Treatment included durvalumab 1500 mg every 4 weeks x 3, olaparib 100 mg twice daily through weeks 1-11 concurrent with paclitaxel 80 mg/m2 weekly x 12 (DOP) followed by doxorubicin/cyclophosphamide (AC) x 4. The control arm was weekly paclitaxel x 12 followed by AC x 4. All patients undergo serial MRI imaging and imaging response at 3 & 12 weeks combined with accumulating pCR data are used to estimate, and continuously update, predicted pCR rate for the trial arm. Regimens “graduation with success” when the Bayesian predictive probability of success in a 300-patient phase 3 neoadjuvant trial in the appropriate biomarker groups reaches > 85%. Results: A total of 73 patients received DOP treatment including 21 HR- tumors (i.e. triple-negative breast cancer, TNBC) and 52 HR+ tumors between May 2018 – June 2019. The control group included 299 patients with HER2- tumors. The DOP arm graduated in June 2019, 13 months after enrollment had started, for all HER2- negative and the HR+/HER2- cohorts with > 0.85% predictive probabilities of success. 72 patient completed surgery and evaluable for pCR, the final predicted probabilities of success in a future phase III trial to demonstrate higher pCR rate with DOP compared to control are 81% for all HER2- cancers (estimated pCR rate 37%), 80% for TNBC (estimated pCR rate 47%) and 74.5% for HR+/HER2- patients (estimated pCR rate 28%). Association between pCR and germline BRCA status and immune gene expression including PDL1 will be presented at the meeting. No unexpected toxicities were seen, but 10 patients (14%) had possibly immune or olaparib related grade 2/3 AEs (3 pneumonitis, 2 adrenal insufficiency, 1 colitis, 1 pancreatitis, 2 elevated LFT, 1 skin toxicity, 2 hypothyroidism, 1 hyperthyroidism, 1 esophagitis). Conclusion: I-SPY2 demonstrated a significant improvement in pCR with durvalumab and olaparib included with paclitaxel compared to chemotherapy alone in women with stage II/III high-risk, HER2-negative breast cancer, improvement was seen in both the HR+ and TNBC subsets.
This combination of durvalumab and olaparib is safe in triple negative breast cancer
expected synergy between PARP inhibitors and PDL1 inhibitors as olaparib inhibits DNA repair and would increase the mutational burden, which is in lung cancer shown to be a biomarker for efficacy of immune checkpoint inhibitors such as Opdivio
three subsets of breast cancers were studied: her2 negative, triple negative and ER+ tumors
MRI imaging tumor size was used as response
olaparib arm had elevation of liver enzymes and there was a pancreatitis
however paclitaxel was used within the combination as well as a chemo arm but the immuno arm alone may not be better than chemo alone but experimental arm with all combo definitely better than chemo alone
they did not look at BRCA1/2 status, followup talk showed that this is a select group that may see enhanced benefit; PARP inhibitors were seen to be effective only in BRCA1/2 mutant ovarian cancer previously
10:10 AM – 10:20 AM
CT012 – Evaluation of atezolizumab (A), cobimetinib (C), and vemurafenib (V) in previously untreated patients with BRAFV600 mutation-positive advanced melanoma: Primary results from the phase 3 IMspire150 trial Grant A. McArthur,
AbstractBackground: Approved systemic treatments for advanced melanoma include immune checkpoint inhibitor therapy (CIT) and targeted therapy with BRAF plus MEK inhibitors for BRAFV600E/K mutant melanoma. Response rates with CITs are typically lower than those observed with targeted therapy, but CIT responses are more durable. Preclinical and clinical data suggest a potential for synergy between CIT and BRAF plus MEK inhibitors. We therefore evaluated whether combining CIT with targeted therapy could improve efficacy vs targeted therapy alone. Methods: Treatment-naive patients with unresectable stage IIIc/IV melanoma (AJCC 7th ed), measurable disease by RECIST 1.1, and BRAFV600 mutations in their tumors were randomized to the anti-programmed death-ligand 1 antibody A + C + V or placebo (Pbo) + C + V. A or Pbo were given on days 1 and 15 of each 28-day cycle. Treatment was continued until disease progression or unacceptable toxicity. The primary outcome was investigator-assessed progression-free survival (PFS). Results: 514 patients were enrolled (A + C + V = 256; Pbo + C + V = 258) and followed for a median of 18.9 months. Investigator-assessed PFS was significantly prolonged with A + C + V vs Pbo + C + V (15.1 vs 10.6 months, respectively; hazard ratio: 0.78; 95% confidence interval: 0.63-0.97; P=0.025), an effect seen in all prognostic subgroups. While objective response rates were similar in the A + C + V and Pbo + C + V groups, median duration of response was prolonged with A + C + V (21.0 months) vs Pbo + C + V (12.6 months). Overall survival data were not mature at the time of analysis. Common treatment-related adverse events (AEs; >30%) in the A + C + V and Pbo + C + V groups were blood creatinine phosphokinase (CPK) increase (51.3% vs 44.8%), diarrhea (42.2% vs 46.6%), rash (40.9% in both arms), arthralgia (39.1% vs 28.1%), pyrexia (38.7% vs 26.0%), alanine aminotransferase (ALT) increase (33.9% vs 22.8%), and lipase increase (32.2% vs 27.4%). Common treatment-related grade 3/4 AEs (>10%) that occurred in the A + C + V and Pbo + C + V groups were lipase increase (20.4% vs 20.6%), blood CPK increase (20.0% vs 14.9%), ALT increase (13.0% vs 8.9%), and maculopapular rash (12.6% vs 9.6%). The incidence of treatment-related serious AEs was similar between the A + C + V (33.5%) and Pbo + C + V (28.8%) groups. 12.6% of patients in the A + C + V group and 15.7% in the Pbo + C + V group stopped all treatment because of AEs. The safety profile of the A + C + V regimen was generally consistent with the known profiles of the individual components. Conclusion: Combination therapy with A + C + V was tolerable and manageable, produced durable responses, and significantly increased PFS vs Pbo + C + V. Thus, A + C + V represents a viable treatment option for BRAFV600 mutation-positive advanced melanoma. ClinicalTrials.gov ID: NCT02908672
10:25 AM – 10:35 AM
CT013 – SWOG S1320: Improved progression-free survival with continuous compared to intermittent dosing with dabrafenib and trametinib in patients with BRAF mutated melanoma Alain Algazi,
AbstractBackground: BRAF and MEK inhibitors yield objective responses in the majority of BRAFV600E/K mutant melanoma patients, but acquired resistance limits response durations. Preclinical data suggests that intermittent dosing of these agents may delay acquired resistance by deselecting tumor cells that grow optimally in the presence of these agents. S1320 is a randomized phase 2 clinical trial designed to determine whether intermittent versus continuous dosing of dabrafenib and trametinib improves progression-free survival (PFS) in patients with advanced BRAFV600E/K melanoma. Methods: All patients received continuous dabrafenib and trametinib for 8-weeks after which non-progressing patients were randomized to receive either continuous treatment or intermittent dosing of both drugs on a 3-week-off, 5-week-on schedule. Unscheduled treatment interruptions of both drugs for > 14 days were not permitted. Responses were assessed using RECIST v1.1 at 8-week intervals scheduled to coincide with on-treatment periods for patients on the intermittent dosing arm. Adverse events were assessed using CTCAE v4 monthly. The design assumed exponential PFS with a median of 9.4 months using continuous dosing, 206 eligible patients and 156 PFS events. It had 90% power with a two-sided α = 0.2 to detect a change to a median with an a priori hypothesis that intermittent dosing would improve the median PFS to 14.1 months using a Cox model stratified by the randomization stratification factors. Results: 242 patients were treated and 206 patients without disease progression after 8 weeks were randomized, 105 to continuous and 101 to intermittent treatment. 70% of patients had not previously received immune checkpoint inhibitors. There were no significant differences between groups in terms of baseline patient characteristics. The median PFS was statistically significantly longer, 9.0 months from randomization, with continuous dosing vs. 5.5 months from randomization with intermittent dosing (p = 0.064). There was no difference in overall survival between groups (median OS = 29.2 months in both arms p = 0.93) at a median follow up of 2 years. 77% of patient treated continuously discontinued treatment due to disease progression vs. 84% treated intermittently (p = 0.34). Conclusions: Continuous dosing with the BRAF and MEK inhibitors dabrafenib and trametinib yields superior PFS compared with intermittent dosing.
combo of MEK and BRAF inhibitors can attract immune cells like TREGs so PDL1 inhibitor might help improve outcome
PFS was outcome endpoint
LDH was elevated in three patients (why are they seeing liver tox? curious like previous study); are seeing these tox with the PDL1 inhibitors
there was marked survival over placebo group and PFS was statistically with continuous dosing however intermittent dosing shows no improvement
The American Association for Cancer Research (AACR) will hold its Annual Meeting as a Virtual Online Format. Registration is free and open to all, including non members. Please go to
Presentation titles are available through the online meeting planner. The program also includes six virtual poster sessions consisting of brief slide videos. Poster sessions will not be presented live but will be available for viewing on demand. Poster session topics are as follows:
11:45 a.m.-1:30 p.m.
Minisymposium: Emerging Signaling Vulnerabilities in Cancer
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11:45 a.m.-1:15 p.m.
Minisymposium: Advances in Cancer Drug Design and Discovery
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2:00 p.m.-4:50 p.m.
Clinical Plenary: Lung Cancer Targeted Therapy
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1:55 p.m.-4:15 p.m.
Clinical Plenary: Breast Cancer Therapy
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1:30 p.m.-3:30 p.m.
Minisymposium: Drugging Undrugged Cancer Targets
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4:50 p.m.-6:05 p.m.
Symposium: New Drugs on the Horizon 1_______________________
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4:50 p.m.-5:50 p.m.
Minisymposium: Therapeutic Modification of the Tumor Microenvironment or Microbiome
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4:00 p.m.-6:00 p.m.
Minisymposium: Advancing Cancer Research Through An International Cancer Registry: AACR Project GENIE Use Cases__________________________
All session times are EDT.
TUESDAY, APRIL 28
Channel 1
Channel 2
Channel 3
9:00 a.m.-101:00 a.m.
Clinical Plenary: COVID-19 and Cancer
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11:00 a.m.-1:35 p.m.
Clinical Plenary: Adoptive Cell Transfer Therapy__________________________
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10:45 a.m.-12:30 p.m.
Symposium: New Drugs on the Horizon 2_________________________
2012pharmaceutical
sjwilliamspa