bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract B22: Mdig gene-environment interaction in human cancers
Authors: Thakur Chitra , Chen Fei
Published: December 2017

Mineral dust-induced gene, mdig has recently been identified and is known to be over expressed in a majority of human cancers and holds predictive power in the poor prognosis of the disease. Mdig is an environmentally expressed gene that is involved in cell proliferation, neoplastic transformation and immune regulation. With the advancement in deciphering the prognostic role of mdig in human cancers, our understanding on how mdig renders a normal cell to undergo malignant transformation is still very limited. This work displays the current knowledge of the mdig gene in context to human neoplasias and its relation to the clinico-pathologic factors predicting the outcome of the disease in patients. It also emphasizes on the promising role of mdig that can serve as a potential candidate for biomarker discovery and as a therapeutic target in inflammation and cancers. Considering the recent advances in understanding the underlying mechanisms of tumor formation, more preclinical and clinical research is required to validate the potential of using mdig as a novel biological target of therapeutic and diagnostic value.

Summary: Expression level of mdig influences the prognosis of several human cancers especially cancers of the breast and lung. Evaluation of mdig in cancers can offer novel biomarker with potential therapeutic interventions for the early assessment of cancer development in patients.

Citation Format: Chitra Thakur, Fei Chen. Mdig gene-environment interaction in human cancers [abstract]. In: Proceedings of the AACR Precision Medicine Series: Opportunities and Challenges of Exploiting Synthetic Lethality in Cancer; Jan 4-7, 2017; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2017;16(10 Suppl):Abstract nr B22.
Abstract B33: Tgif inactivation defines a synthetic lethal interaction among oncogenic Kras and Twist1 in pancreatic ductal adenocarcinoma
Authors: Parajuli Parash , Singh Purba , Wang Zhe , Kumar Santosh , Li Lena , Eragamreddi Sailaja , Nguyen Thien Ly , Younes Subhi Talal , Zhang Xu , Xu Keli , Razzaque Mohammed , Prunier Céline , Atfi Azeddine
Published: December 2017

The homeodomain protein TGIF function as a potent inhibitor of transforming growth factor beta (TGF-β) cytostatic signaling, whose inactivation is deemed instrumental to the pathogenesis and progression of pancreatic ductal adenocarcinoma (PDAC) driven by oncogenic Kras. Surprisingly, we found that deletion of Tgif in the context of mutant Kras (KrasG12D) expression culminated in the development of highly metastatic PDAC, despite leading to hyperactivation of TGF-(β/Smad) signaling. Mechanically, we found that TGIF associated with and antagonized Twist1 by a process involving Smad4, a tumor suppressor that is frequently inactivated in human PDAC. Along these lines, Twist1 overexpression synergized with KrasG12D to induce PDAC progression, whereas its ablation completely blocked the malignant phenotype driven by the combined KrasG12D expression and TGIF ablation. Thus, by demonstrating that TGIF functions as a tumor suppressor in PDAC owing to its ability to antagonize the pro-malignant transcription factor Twist1, our studies provide key insights into the role of Twist1 that could be exploited to design synthetic lethal therapeutics against oncogenic Kras, which has proven so far to be intractable.

Citation Format: Parash Parajuli, Purba Singh, Zhe Wang, Santosh Kumar, Lena Li, Sailaja Eragamreddi, Thien Ly Nguyen, Subhi Talal Younes, Xu Zhang, Keli Xu, Mohammed Razzaque, Céline Prunier, Azeddine Atfi. Tgif inactivation defines a synthetic lethal interaction among oncogenic Kras and Twist1 in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Precision Medicine Series: Opportunities and Challenges of Exploiting Synthetic Lethality in Cancer; Jan 4-7, 2017; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2017;16(10 Suppl):Abstract nr B33.
Abstract IA06: Leveraging genome-wide CRISPR screens and synthetic lethal interactions for novel cancer therapeutics
Authors: Angers Stephane
Published: December 2017

Forward genetic screens with CRISPR-Cas9 genome editing enable high-resolution detection of genetic vulnerabilities in cancer cells. We conducted genome-wide CRISPR-Cas9 screens in RNF43 mutant pancreatic ductal adenocarcinoma (PDAC) cells, which rely on Wnt signaling for proliferation, and discovered a unique requirement for a Wnt signaling circuit engaging FZD5, one of the ten Frizzled receptors encoded in the human genome. Our results uncover an underappreciated level of context dependent specificity at the Wnt receptor level. We further derived a panel of recombinant antibodies that reports the expression of nine FZD proteins and confirm that FZD5 functional specificity cannot be explained by protein expression patterns. Antibodies that specifically bind FZD5 and FZD8 also robustly inhibited the growth of RNF43 mutant PDAC cells grown in vitro and as xenografts in vivo, providing strong orthogonal support for the functional specificity observed genetically. Proliferation of a patient-derived PDAC cell line harboring a RNF43 variant previously associated with PDAC was also selectively inhibited by the FZD5 antibodies, further demonstrating their use as a potential targeted therapy. Highlighting the potential generalizability of these findings, beyond PDAC, tumor organoid cultures from colorectal carcinoma patients that carried RNF43 mutations were also sensitive to the FZD5 antibodies. Our results provide the first example of how CRIPSR-based genetic screens can be leveraged to identify and validate cell surface targets for antibody development and cancer therapy.

Citation Format: Stephane Angers. Leveraging genome-wide CRISPR screens and synthetic lethal interactions for novel cancer therapeutics [abstract]. In: Proceedings of the AACR Precision Medicine Series: Opportunities and Challenges of Exploiting Synthetic Lethality in Cancer; Jan 4-7, 2017; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2017;16(10 Suppl):Abstract nr IA06.
Abstract IA07: Defining, Optimizing, and Altering the Specificities of CRISPR-Cas Nucleases
Authors: Joung J. Keith
Published: December 2017

RNA-guided CRISPR-Cas nucleases are now widely used for research and are also being rapidly developed as novel therapeutics for various human diseases. In this talk, I will discuss methods developed by our group that enable unbiased, genome-wide assessment of off-target cleavage specificities of CRISPR-Cas nucleases in human cells. I will also summarize our efforts to use protein engineering to create CRISPR-Cas nuclease variants that robustly show substantially reduced off-target effects and/or altered DNA recognition specificities. Taken together, our results have yielded reagents, methods, and insights that will be important for research applications and potential clinical translation of these programmable nucleases.

Citation Format: J. Keith Joung. Defining, Optimizing, and Altering the Specificities of CRISPR-Cas Nucleases [abstract]. In: Proceedings of the AACR Precision Medicine Series: Opportunities and Challenges of Exploiting Synthetic Lethality in Cancer; Jan 4-7, 2017; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2017;16(10 Suppl):Abstract nr IA07.
Abstract IA12: Widespread rewiring of genetic interaction networks upon cancer pathway activation
Authors: Boutros Michael
Published: December 2017

Genetic interactions can reconstruct the wiring diagram of biological processes in health and disease. Gene-gene interactions are identified by simultaneously perturbing multiple gene products and identifying instances when the expected and experimentally measured phenotypes differ, e.g. aggravating or buffering phenotypic outcomes. Systematic gene-gene depletion experiment have been used to build comprehensive maps of cellular processes in unicellular and multicellular organisms, to place novel components into the context of known pathways and delineate epistatic relationships between components.

Cellular signaling networks coordinate physiological processes in all multicellular organisms. Within signaling networks, the interplay of different modules controls signaling activity dependent onto the cellular context. We here generated a context-dependent genetic interaction network of a Wnt signaling pathway, which has been implicated in many developmental and oncogenic processes. To assess changes in genetic network architecture, we measured >290,000 double perturbations in a baseline state, after activation by Wnt ligands or loss of the tumor suppressor APC. We found that genetic interactions within the Wnt network globally rewired after pathway activation. Distinct groups of responsive functional relations were identified in the between-state or state-specific networks. State-dependent and between-state genetic interaction maps identified responsive functional modules in networks with specific functions.

Citation Format: Michael Boutros. Widespread rewiring of genetic interaction networks upon cancer pathway activation [abstract]. In: Proceedings of the AACR Precision Medicine Series: Opportunities and Challenges of Exploiting Synthetic Lethality in Cancer; Jan 4-7, 2017; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2017;16(10 Suppl):Abstract nr IA12.
Abstract IA16: Systematic mapping and modeling of genetic interaction networks in cancer cells
Authors: Ideker Trey
Published: December 2017

We have developed a systematic approach to map human genetic networks by combinatorial CRISPR-Cas9 perturbation coupled to robust analysis of growth kinetics. To demonstrate this approach, we targeted all gene pairs among a set of 73 known cancer genes with multiplexed guide RNAs in two cell lines, testing 23,652 combinations. Numerous therapeutically relevant interactions are identified, most private to one cell line. In parallel, we are developing bioinformatic approaches that analyze genetic interactions to construct hierarchical models of cancer pathways. I will discuss means by which these hierarchical models can be used to aggregate and interpret tumor mutations.

Citation Format: Trey Ideker. Systematic mapping and modeling of genetic interaction networks in cancer cells [abstract]. In: Proceedings of the AACR Precision Medicine Series: Opportunities and Challenges of Exploiting Synthetic Lethality in Cancer; Jan 4-7, 2017; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2017;16(10 Suppl):Abstract nr IA16.
Abstract IA20: Chemical-genetic interaction maps for precision therapies in breast and ovarian cancers
Authors: Bandyopadhyay Sourav
Published: December 2017

There is an urgent need in oncology to link molecular aberrations in tumors with therapeutics that can be administered in a personalized fashion. One approach identifies synthetic-lethal genetic interactions or emergent dependencies that cancer cells acquire in the presence of specific mutations. Using breast epithelial cells as a base we have developed methodologies to connect tumor mutations with drug sensitivity using quantitative functional genomic screens to create chemical-genetic interaction maps. The focus of the lab is to use these maps to uncover new synthetic-lethal relationships and identify new biomarkers for targeted as well as chemotherapy. I will describe new approaches to use these quantitative maps to uncover drug mechanism of action as well as integrate with cancer cell line collections to predict drug responses in cancer.

Citation Format: Sourav Bandyopadhyay. Chemical-genetic interaction maps for precision therapies in breast and ovarian cancers [abstract]. In: Proceedings of the AACR Precision Medicine Series: Opportunities and Challenges of Exploiting Synthetic Lethality in Cancer; Jan 4-7, 2017; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2017;16(10 Suppl):Abstract nr IA20.
Abstract IA21: Systematic, network-based elucidation of synthetic lethal proteins and synergistic compounds
Authors: Califano Andrea
Published: December 2017

Given the complex nature of cancer and the cell's ability to effectively compensate for individual perturbation through evolutionarily honed adaptive mechanisms, there is strong expectation that combination therapy approaches may be required to address the limitations that have emerged from single agent therapy. Synthetic lethality provides strong biological rationale supporting this observation, although mechanisms of compound synergy and sensitization are in general more complex than individual gene-pair interactions. Synthetic lethal genes have been elucidated mainly via large-scale screens in model organisms, or by pooled shRNA/CRISPR screens in cells harboring specific genetic events, or based on mechanistic understanding of specific pathways. These methodologies are laborious, expensive, and prone to significant false positive and negative rates due to the nature of pooled screens. More importantly, results are often idiosyncratic, depending on the specific genetic and epigenetic context of the cellular models used in the analysis.

To address these challenges, we have developed network-based methods to identify master regulator proteins that are responsible for maintaining tumor state, despite being rarely mutated using only patient-derived data. Master regulators are highly enriched in synthetic lethal interactions that can be elucidated computationally, via protein-target analysis. Furthermore, the approach can be trivially extended to elucidate synergistic drug interaction, based on perturbational assays of individual compounds. In this presentation, we will address the discovery of synthetic lethal genes and synergistic compounds in several tumor contexts, including lymphoma, breast cancer, prostate cancer, and glioma, which has led to the design and implementation of novel clinical trials. We will also discuss integration of these methodologies into an N of 1 protocol, which is currently enrolling 260 patients across 14 distinct malignancies.

Citation Format: Andrea Califano. Systematic, network-based elucidation of synthetic lethal proteins and synergistic compounds [abstract]. In: Proceedings of the AACR Precision Medicine Series: Opportunities and Challenges of Exploiting Synthetic Lethality in Cancer; Jan 4-7, 2017; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2017;16(10 Suppl):Abstract nr IA21.
Abstract IA22: Exploiting the heterogeneity of mutant Kras lung tumors to improve therapy
Authors: Martins Carla
Published: December 2017

Lung cancer is currently the most lethal cancer worldwide with non-small cell lung carcinoma (NSCLC) accounting for ~85% of all cases. The vast majority of lung cancer patients present with locally advanced, inoperable or metastatic disease and median survival at this stage remains low. Targeted therapies are already improving treatment outcomes, but frequent mutations such as those affecting KRAS (present in ~30% of lung adenocarcinomas, a common subtype of NSCLC) still remain untargetable. Our lab aims to define new vulnerabilities associated with these aggressive and largely therapy-resistant tumors. To achieve this, we are characterizing the mechanisms that drive the malignant progression of mutant Kras lung tumors, using mouse models that closely recapitulate human lung adenocarcinoma. Using a multidisciplinary approach we recently identified distinct genetic, transcriptional and metabolic signatures between low grade and high grade mutant Kras lung tumors. In particular, we showed that high grade mutant Kras lung adenocarcinomas frequently exhibit extra copies of mutant Kras, implying that enhanced mutant Kras activity is positively selected during malignant progression. Moreover, we showed that the gain of just a single mutant copy (single vs double mutant) has a major effect on lung tumour cells in vitro and in vivo, leading to enhanced metastatic potential and metabolic rewiring. In turn, this metabolic rewiring creates unique dependences that can be exploited to selectively target advanced mutant Kras lung tumours. Our work shows that mutant Kras lung tumors are not a single disease, comprising two classes of tumors with mutant Kras allelic content-dependent prognosis and therapeutic susceptibilities. This intrinsic tumor heterogeneity is also present in the human disease and may have contributed to the poor therapeutic responses often associated with mutant KRAS lung tumors in humans. We are currently determining whether this metabolic heterogeneity can be exploited to improve the targeting of human mutant KRAS adenocarcinoma.

Citation Format: Carla Martins. Exploiting the heterogeneity of mutant Kras lung tumors to improve therapy [abstract]. In: Proceedings of the AACR Precision Medicine Series: Opportunities and Challenges of Exploiting Synthetic Lethality in Cancer; Jan 4-7, 2017; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2017;16(10 Suppl):Abstract nr IA22.
Abstract IA23: Overcoming drug resistance and tumor heterogeneity in gastrointestinal cancers
Authors: Corcoran Ryan B.
Published: December 2017

Personalized cancer medicine approaches, inhibiting kinases in tumors driven by defined genomic alterations, have demonstrated striking efficacy in many cancer types. However, the development of drug resistance is a major limitation to the efficacy of targeted therapies in oncology. Identifying and understanding the molecular mechanisms driving resistance may foster opportunities to develop therapeutic strategies to overcome resistance. For example, in the ~10% of colorectal cancer patients whose tumors harbor BRAF V600 mutations, we have found that feedback reactivation of MAPK signaling, often mediated by EGFR, underlies the relative insensitivity of these cancers to RAF inhibitors. The development of targeted therapy combination strategies to block feedback reactivation of MAPK signaling has led to marked improvements in response rates for these patients from ~5% to >30% over the past few years. However, in patients who respond to these targeted combinations, the rapid development of acquired resistance still limits clinical benefit. Acquired resistance in BRAF mutant colorectal cancer and in other molecularly-defined tumor types can be marked by the development of extensive molecular heterogeneity due to the selection of sub-clonal tumor cell populations, capable of growing under drug pressures, which poses significant diagnostic and therapeutic challenges. We will present data demonstrating how a single-lesion biopsy at disease progression to diagnose the mechanism of acquired resistance can vastly underrepresent the molecular heterogeneity of resistant tumor clones in an individual patient, and may fail to detect the existence of distinct but important resistance mechanisms that can drive mixed or lesion-specific responses and treatment failure to subsequent targeted therapy. By contrast, liquid biopsy approaches analyzing circulating tumor DNA have the potential to detect the presence of simultaneous resistance mechanisms residing in separate metastases in a single patient and to monitor the effects of subsequent therapies on specific sub-clonal tumor cell populations. These findings highlight the critical role of tumor heterogeneity in driving therapeutic resistance and how convergent targeted therapy strategies blocking common signaling nodes capable of overcoming multiple resistance mechanisms may be needed.

Citation Format: Ryan B. Corcoran. Overcoming drug resistance and tumor heterogeneity in gastrointestinal cancers [abstract]. In: Proceedings of the AACR Precision Medicine Series: Opportunities and Challenges of Exploiting Synthetic Lethality in Cancer; Jan 4-7, 2017; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2017;16(10 Suppl):Abstract nr IA23.
Abstract PR01: A functional variomic chemi-genetic screen in C. elegans identifies new synthetic lethal interactions with PARP inhibition that are conserved from worm to human
Authors: O'Neil Nigel J. , Bailey Melanie L. , Hieter Philip
Published: December 2017

Poly ADP-ribose polymerase (PARP) inhibitors are anti-cancer therapeutics that are synthetic lethal (SL) with mutations affecting the homologous recombination genes BRCA1 or BRCA2. Previous work from our lab found that cohesin mutations, which are common in a range of tumour types, also confer sensitivity to PARP inhibition. We want to extend the SL profile of PARP inhibitors to identify the full spectrum of genetic variants that result in sensitivity to PARP inhibitors alone or in combination with DNA damaging agents.

To this end, we are using the model organism Caenorhabditis elegans to screen for new SL interactions with PARP inhibitors. C. elegans provides an excellent in vivo system with which to investigate SL interactions with cancer-associated mutations, as many of the pathways and genes implicated in cancer are conserved between humans and C. elegans. In many ways, C. elegans is an animal model that combines the technical advantages of a single celled organism, such as yeast, with increased developmental complexity and a gene complement more akin to humans.

We have developed a high throughput in vivo variomics approach using the C. elegans Million Mutation Project strain collection to screen 2,000 mutagenized and sequenced strains containing >800,000 homozygous genetic variations. To date we have found 16 strains that were sensitive to the PARP inhibitor olaparib. Frequency analysis of the variants in the sensitive strains identified multiple mutations affecting mus-81 and eme-1, which comprise the structure specific Mus81 endonuclease. Further investigation of the interaction with the Mus81 endonuclease mutants found that PARP inhibitor-treated mus-81 and eme-1 mutants exhibit profound somatic proliferation defects characterized by persistent anaphase bridges and that the mus-81 PARP inhibitor-mediated synthetic lethality was not suppressed by loss of non-homologous end joining proteins.

We found that the synthetic lethality between MUS81 mutations and PARP inhibitor treatment is conserved in human cells. Similar to C. elegans, PARP inhibitor treated MUS81 knockout cells accumulate anaphase bridges and exhibit a phenotype distinct from PARP inhibitor treated BRCA2 knockout cells.

Our variomic screening approach has identified new SL interactions with PARP inhibitors and has expanded our understanding of the mechanism underlying PARP inhibitor-mediated synthetic lethality.

Citation Format: Nigel J. O’Neil, Melanie L. Bailey, Philip Hieter. A functional variomic chemi-genetic screen in C. elegans identifies new synthetic lethal interactions with PARP inhibition that are conserved from worm to human [abstract]. In: Proceedings of the AACR Precision Medicine Series: Opportunities and Challenges of Exploiting Synthetic Lethality in Cancer; Jan 4-7, 2017; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2017;16(10 Suppl):Abstract nr PR01.
Abstract PR03: Linking AP/MS-driven protein-protein interaction networks and combination CRISPR/sgRNA screens defines new Kras effectors and target candidates for non-small cell lung cancer
Authors: Kelly Marcus R. , Kyuho Han , Jeng Edwin E. , Morgans David , Kostyrko Kaja , Simpson David , Gwinn Dana , Sweet-Cordero Alejandro , Bassik Michael C. , Jackson Peter K.
Published: December 2017

The Kras pathway is a central driver in prevalent and deadly cancers including pancreas, colon and lung. Despite decades of work studying the Raf and PI3 kinase pathways downstream of Kras, therapies targeted to these pathways have shown varied responses in tumors

To better understand whether important Kras dependences have been overlooked, we used tandem affinity purification of Kras, Hras, and Nras interactors and a set of baits representing ~50 interacting pathway regulators, and have compared these interactions in Kras transformed A549 NSCLC lines versus an isogenic shRNA Kras knockdown line, to identify key protein-protein interactions (PPIs) linked to Kras effector activity. These interactions were curated and compared to public PPI, genetic susceptibility, and other multiomics data to assemble a physical PPI map annotated with important functional determinants. This functional map was used to construct a library of 114 selected sgRNAs (10 guides per gene) and screened in a 1140 x 1140 dual sgRNA vector system to look for quantitative changes in single and dual genetic dependencies in A549 cell growth. We discovered a considerable number of new KRAS GTP-specific effectors important in NSCLC cancer, many with strong mutations patterns supported by TCGA data and validated by in vitro biochemical assay. We will present these data and additional validation studies on two pathways including the Radil-Rap1-Kif14 pathway for cell migration and an extensive interaction of the Kras pathway with Ral and Rap GTPase family guanine nucleotide exchange factors. These new effectors underscore limitations in our functional understanding of transformation in Kras-driven tumors and suggest specific new targets for these critical tumors.

Citation Format: Marcus R. Kelly, Han Kyuho, Edwin E. Jeng, David Morgans, Kaja Kostyrko, David Simpson, Dana Gwinn, Alejandro Sweet-Cordero, Michael C. Bassik, Peter K. Jackson. Linking AP/MS-driven protein-protein interaction networks and combination CRISPR/sgRNA screens defines new Kras effectors and target candidates for non-small cell lung cancer [abstract]. In: Proceedings of the AACR Precision Medicine Series: Opportunities and Challenges of Exploiting Synthetic Lethality in Cancer; Jan 4-7, 2017; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2017;16(10 Suppl):Abstract nr PR03.
Abstract PR06: CRISPR screens identified drivers of endocrine resistance and synthetic lethal vulnerabilities in breast cancer
Authors: Xiao Tengfei , Li Wei , Wang Xiaoqing , Xu Han , Wu Qiu , Jiang Peng , Yang Jixin , Fei Teng , Zang Chongzhi , Liao Qi , Rennhack Jonathan , Andrechek Eran , Li Nanlin , Jeselsohn Rinath , Liu Shirley X. , Brown Myles
Published: December 2017

Estrogen receptor positive (ER+) breast cancer is treated with endocrine therapies, although in advanced disease therapeutic resistance almost invariably develops. Using genome-wide CRISPR screens we identified genes essential for the growth of ER+ breast cancers. More importantly, we also identified genes whose loss confers endocrine resistance. Notably the expression of c-src tyrosine kinase (CSK) is driven by estrogen yet loss of CSK promoted estrogen independent growth. A synthetic lethality screen for CSK loss identified the p21 protein-activated kinase (PAK2) which becomes activated by SRC-family kinases (SFK) in the absence of CSK. CSK loss or PAK2 over-expression predict worse clinical outcome in breast cancer cohorts. Inhibitors of PAK2 or SFK block estrogen-independent breast tumor growth. These findings reveal an estrogen-induced negative feedback loop that constrains the growth of ER+ tumors thereby limiting the efficacy of therapies that inhibit ER and suggest a previously unappreciated therapeutic route to overcoming endocrine resistance.

Citation Format: Tengfei Xiao, Wei Li, Xiaoqing Wang, Han Xu, Qiu Wu, Peng Jiang, Jixin Yang, Teng Fei, Chongzhi Zang, Qi Liao, Jonathan Rennhack, Eran Andrechek, Nanlin Li, Rinath Jeselsohn, Shirley X. Liu, Myles Brown. CRISPR screens identified drivers of endocrine resistance and synthetic lethal vulnerabilities in breast cancer [abstract]. In: Proceedings of the AACR Precision Medicine Series: Opportunities and Challenges of Exploiting Synthetic Lethality in Cancer; Jan 4-7, 2017; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2017;16(10 Suppl):Abstract nr PR06.
Abstract 08: Impaired H3K36 methylation defines a subset of head and neck squamous cell carcinomas
Authors: Lu Chao , Papillon-Cavanagh Simon , Gayden Tenzin , Mikael Leonie G. , Bechet Denise , Karamboulas Christina , Ailles Laurie , Karamchandani Jason , Marchione Dylan M. , Garcia Benjamin A. , Weinreb Ilan , Goldstein David , Lewis Peter W. , Dancu Octavia-Maria , Dhaliwal Sandeep , Stecho William , Howlett Christopher J. , Mymryk Joe S. , Barrett John W. , Nichols Anthony C. , Allis C David , Majewski Jacek , Jabado Nada
Published: December 2017

Human papillomavirus (HPV)-negative head and neck squamous cell carcinomas (HNSCCs) are deadly and common cancers. Recent genomic studies implicate multiple genetic pathways, including cell signaling, cell cycle and immune evasion, in their development. Here we analyze public data sets and uncover a previously unappreciated role of epigenome deregulation in the genesis of 13% of HPV-negative HNSCCs. Specifically, we identify novel recurrent mutations encoding p.Lys36Met (K36M) alterations in multiple H3 histone genes. We further validate the presence of these alterations in multiple independent HNSCC data sets and show that, along with previously described NSD1 mutations, they correspond to a specific DNA methylation cluster. The K36M substitution and NSD1 defects converge on altering methylation of histone H3 at K36 (H3K36), subsequently blocking cellular differentiation and promoting oncogenesis. Our data further indicate limited redundancy for NSD family members in HPV-negative HNSCCs and suggest a potential role for impaired H3K36 methylation in their development. Further investigation of drugs targeting chromatin regulators is warranted in HPV-negative HNSCCs driven by aberrant H3K36 methylation.

Citation Format: Chao Lu, Simon Papillon-Cavanagh, Tenzin Gayden, Leonie G. Mikael, Denise Bechet, Christina Karamboulas, Laurie Ailles, Jason Karamchandani, Dylan M. Marchione, Benjamin A. Garcia, Ilan Weinreb, David Goldstein, Peter W. Lewis, Octavia-Maria Dancu, Sandeep Dhaliwal, William Stecho, Christopher J. Howlett, Joe S. Mymryk, John W. Barrett, Anthony C. Nichols, C David Allis, Jacek Majewski, Nada Jabado. Impaired H3K36 methylation defines a subset of head and neck squamous cell carcinomas [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Optimizing Survival and Quality of Life through Basic, Clinical, and Translational Research; April 23-25, 2017; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(23_Suppl):Abstract nr 08.
Abstract 33: CEACAM1 blockade increases NK cell cytotoxicity in head and neck squamous cell carcinoma
Authors: Tam Kenric , Lee Yunqin , Schoppy David , Sunwoo John B.
Published: December 2017

In conjunction with advances made in cytotoxic chemotherapy, radiation, and surgery, immunotherapy has emerged in recent years as a promising fourth modality of treatment for head and neck squamous cell carcinoma (HNSCC). Cetuximab, an anti-EGFR antibody, is now routinely used as an adjunct to radiation therapy and in the recurrent/metastatic setting following treatment failure with concurrent cisplatin and radiation. Understanding the fundamental mechanisms by which HNSCC evades the immune system will aid the development of new therapies and strategies to augment an antitumor immune response.

Carcinoembryonic-antigen-related cell-adhesion molecule 1 (CEACAM1) is a cell surface receptor that is expressed on HNSCC cells, as well as on lymphocytes, such as NK cells. Overexpression of CEACAM1 in HNSCC has been associated with a poor prognosis, higher clinical stage, recurrence, and lymph node metastasis. A phase I trial (NCT02346955) of an anti-CEACAM1 antibody is currently underway for a variety of non-HNSCC malignancies.

We demonstrate that in mice inoculated with TUBO-EGFR, a murine cancer cell line, treatment with an anti-CEACAM1 antibody rescues NK cell effector function from exhaustion resulting in reduced tumor growth and enhanced antibody-dependent cell-mediated cytotoxicity. The addition of Cetuximab has an additive effect and results in additional tumor shrinkage. Thus, these data indicate that CEACAM1 is a novel checkpoint molecule on NK cells.

CEACAM1 is also expressed on tumor cells themselves; its expression in HNSCC is associated with suppression of NK cell cytotoxicity. In vitro co-incubation of NK cells with PCI-13, a human HNSCC cell line, results in IFNγ-mediated upregulation of CEACAM1 on the tumor cells. IFNγ-exposed cells are more resistant to NK cytotoxicity compared to untreated cells, suggesting that immune pressure induces upregulation of NK inhibitors. Importantly, CEACAM1+ NK cells have decreased cytotoxicity against HNSCC tumor cells compared to CEACAM1- NK cells, but the addition of an anti-CEACAM1 antibody restores NK cell effector function. Together, these data indicate that CEACAM1 acts as a checkpoint molecule and that a blocking antibody against CEACAM1 releases its immunosuppressive effects and could serve as a novel immunotherapy for HNSCC.

Citation Format: Kenric Tam, Yunqin Lee, David Schoppy, John B. Sunwoo. CEACAM1 blockade increases NK cell cytotoxicity in head and neck squamous cell carcinoma [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Optimizing Survival and Quality of Life through Basic, Clinical, and Translational Research; April 23-25, 2017; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(23_Suppl):Abstract nr 33.
Abstract 34: Wee1 inhibition sensitizes tumor cells with variable antigenicity to T cell mediated lysis
Authors: Moore Ellen , Sun Lillian , Friedman Jay , Waes Carter Van , Allen Clint
Published: December 2017

Antigen-specific elimination of tumor cells by cytotoxic T-lymphocytes (CTL) inherently relies upon the sensitivity of target cells to effector products such as granzyme B, TNFa, TNF-related apoptosis-inducing ligand (TRAIL), and Fas ligand (FasL). Cell cycle progression is critically required for granzyme B and TNF superfamily-induced apoptosis. Thus, we hypothesized that inhibition of Wee1 with AZD1775 would release the G2/M cell cycle checkpoint and enhance sensitivity of oral cavity cancer cells to CTL killing. To explore this hypothesis, we stably transduced murine oral cancer 1 (MOC1) cells with a construct encoding the fluorescent protein mKate2 and SIINFEKL, the H2-Kb-restricted epitope of ovalbumin (MOC1mK2SIIN). Using in-vitro generated SIINFEKL-specific OT-1 CTLs as effectors, we demonstrated in a real-time, impedance-based assay of cytotoxicity that physiologic concentrations of AZD1775 (250 nM) significantly sensitized MOC1mK2SIIN cells to CTL killing at low E:T ratios. The same concentration of AZD1775 had negligible effects on the MOC1mK2SIIN cells alone, and OT-1 CTL cytotoxicity was antigen-specific as OT-1 effectors did not kill parental MOC1 cells with or without AZD1775 treatment. This effect was partially reversed with the perforin inhibitor concanamycin A, implicating involvement of granzyme B. Further, by mixing MOC1mK2SIIN and parental MOC1 cells, we could alter the ratio of antigen clonality present within the target cell population. Inhibition of Wee1 with AZD1775 significantly enhanced OT-1 CTL control of target cell populations where 5, 10, 15, 20, 25, and 50% lack SIINFEKL antigen. Treatment of MOC1mK2SIIN and parental MOC1 cells with recombinant TNFa, TRAIL and FasL with and without AZD1775 confirmed enhanced TNF superfamily-induced tumor cell control following Wee1 inhibition. These data suggest that Wee1 inhibition broadly sensitizes antigen positive and negative cells to CTL effector products and that AZD1775 may induce “bystander killing” of antigen negative cells in target cell populations with mixed antigenicity. Experiments combining AZD1775 with immune-activating therapies in vivo are underway.

Citation Format: Ellen Moore, Lillian Sun, Jay Friedman, Carter Van Waes, Clint Allen. Wee1 inhibition sensitizes tumor cells with variable antigenicity to T cell mediated lysis [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Optimizing Survival and Quality of Life through Basic, Clinical, and Translational Research; April 23-25, 2017; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(23_Suppl):Abstract nr 34.
Abstract 52: Dynamic rewiring of apoptotic signaling networks by combined EGFR/FRGR inhibition enhances killing of head and neck squamous tumor by DNA damage
Authors: Dayma Yogesh , Yaffe Michael B.
Published: December 2017

We have previously shown that a subset of triple-negative breast cancers can be dramatically sensitized to killing by DNA-damaging chemotherapy by time-staggered inhibition of EGFR. This sensitization effect results from dynamic re-wiring of apoptotic signaling pathways to engage a caspase-8-dependent cell death mechanism (Figure 1). Here we explored whether combined EGFR and/or FGFR inhibition could enhance the killing of head and neck squamous cell cancers by DNA damaging treatments through a similar re-wiring mechanism.

The epidermal growth factor receptor (EGFR) and FGFR pathways are two of the most dysregulated molecular pathways in human head-and-neck squamous cell carcinoma (HNSCC). Despite overexpression in approximately 90% of HNSCC tumors, EGFR inhibitors alone have not exerted a major therapeutic impact on tumor response or patient survival. A recent study provides evidence that the insensitivity of the majority of HNSCC to EGFR inhibitors is mediated by dominant activity of alternative receptor tyrosine kinase (RTK) systems such as FGFR signaling (Clinical Cancer Research 2011).

We have found that time-staggered administration of either EGFR inhibitors, or FGFR inhibitors, can dramatically enhance the apoptotic response of HNSCCs to DNA damage from doxorubicin. Importantly, combined inhibition of both the EGFR and FGFR pathways was more effective than inhibition of either pathway alone, at inducing sensitization to cytotoxic chemotherapy through dynamic network re-rewiring. Enhanced cell death by dual EGFR/FGFR inhibition and subsequent genotoxic injury results from greater activation of Caspase-8 than that seen by either EGFR or FGFR inhibitors alone. This enhanced Caspase-8 acitivty, together with Caspase-9 activation, accounts for the majority of apoptotic death. Our data further suggest that Src family kinases are a critical downstream node of EGFR/FGFR activity since treatment of HNSCC cell lines with Src kinase inhibitors resulted in similar sensitization to doxorubicin treatment.

In summary, our data extend the utility of therapeutic dynamic rewiring for the targeting of tumors with redundant receptor signaling pathways as well as their critical downstream nodes.

Citation Format: Yogesh Dayma, Michael B. Yaffe. Dynamic rewiring of apoptotic signaling networks by combined EGFR/FRGR inhibition enhances killing of head and neck squamous tumor by DNA damage [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Optimizing Survival and Quality of Life through Basic, Clinical, and Translational Research; April 23-25, 2017; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(23_Suppl):Abstract nr 52.
Abstract 58: Therapeutically targeting the cell cycle in head and neck cancer
Authors: Diab Ahmed , Chang Xu , Kao Michael , Clurman Bruce , Galloway Denise , Eduardo Mendez
Published: December 2017

Head and neck squamous cell carcinomas (HNSCC) have a complex mutational spectrum with tumor suppressor and cell cycle dysregulation as the most prominent features. Additionally, HPV infection has been shown to be a cause of some HNSCC, particularly oropharyngeal cancer, and it is increasing in the US. Our recent studies have established WEE1 inhibition as a new therapeutic strategy in HNSCC. WEE1 inhibition not only leads to premature mitosis by weakening the G2/M checkpoint but also causes replication stress in S-phase particularly in tumors with deficient TP53. Given that HPV infection causes genetic instability by inactivating tumor suppressor pathways (TP53 and Rb) and impairing proper DNA damage repair (DDR) response, we aim to explore targets that will synergize with WEE1 and decrease reliance on chemotherapy.

To this end, we performed a q-PCR array profiling p53 dependent gene expression in a pair of isogenic HNSCC cell lines for p53 knockdown (vs wildtype control). Using a similar profiling technique in an isogenic pair of immortalized human oral keratinocytes (OKF4 cells) over expressing HPV16 E6/E7 proteins, we profiled the expression of DDR genes in response to DNA damage in wildtype vs. E6E7 expressing keratinocytes. A functional high-throughput siRNA library screen for DDR genes was performed to functionally validate the pathways identified. We looked for DDR genes that specifically sensitized p53 deficient HNSCC cells as well as E6/E7 expressing cells to WEE1 inhibition.

TP53 deficient cells exhibited elevated levels of DDR related genes in response to DNA damage when compared to isogenic wildtype. We identified potential survival DDR pathways for E6E7- mediated transformation, targeting of which represents a novel therapeutic strategy. The DDR siRNA screen with WEE1 inhibition provided a functional validation for our findings. Gene ontology analysis of top 10% of WEE1 sensitizers identified BRCA1 related DNA damage response genes as top sensitizers for WEE1 inhibition in p53 deficient cells. Collectively, these results would help develop a new therapeutic paradigm for HPV-positive HNSCC by providing tailored mechanism-based therapies.

Citation Format: Ahmed Diab, Xu Chang, Michael Kao, Bruce Clurman, Denise Galloway, Mendez Eduardo. Therapeutically targeting the cell cycle in head and neck cancer [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Optimizing Survival and Quality of Life through Basic, Clinical, and Translational Research; April 23-25, 2017; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(23_Suppl):Abstract nr 58.
Abstract 68: Functional interactions of HPV and PARP-1 in head and neck cancer
Authors: Gary Cyril S. , Hajek Michael , Biktasova Asel , Sewell Andrew , Wendell Yarbrough G. , Issaeva Natalia
Published: December 2017

Though the overall incidence of head and neck cancer has been declining over the last several decades, there has been a concomitant and worrisome rise in human-papilloma virus (HPV)-associated head and neck squamous cell carcinoma (HNSCC). HPV infection is a necessary but not sufficient condition for cancer development. Unlike in cervical cancer, where several co-factors including smoking and co-infection with other agents are well established, how HPV drives malignant transformation in head and neck cancer and which cellular factors are required are not well characterized. Recent evidence from our group has shown that poly (ADP-ribose) polymerase-1 (PARP-1) is overexpressed and overactive in HPV-positive (HPV(+)), but not HPV-negative (HPV(-)), oropharyngeal squamous cell carcinoma (OPSCC). The significance of PARP-1 overexpression and hyperactivation in cancer is only beginning to emerge. High levels of PARP-1 are found in a fraction of hepatocellular and breast cancers and correlate with poor prognosis. Recently, PARP-1 was implicated in prostate cancer progression. This study explores the role of PARP-1 in HPV infection and HNSCC carcinogenesis.

Biochemical methods were used to determine PARP activity in vitro, in head and neck tumors, and during infection with HPV16 pseudovirus (PsV) or overexpression of HPV16 proteins in epithelial cells. The response to PARP inhibition was evaluated with clonogenic survival assays. HPV L1 mRNA in HNSCC was detected using quantitative real-time PCR and HPV L1 protein levels were determined by immunohistochemistry.

Here, we show that the HPV16 major capsid protein L1 directly binds PARP-1 and activates poly(ADP-ribosyl)ation in the absence of DNA damage in vitro and in HPV(-) cells. Using PARP-1 knockout cells, we found that PARP-1 expression and enzymatic activity supports initial HPV infection. Furthermore, HPV(-) cells were sensitized to PARP inhibition both after L1 overexpression and after infection with HPV16 PsV particles.

In conclusion, we report functional interactions between the viral capsid and cellular protein, signifying a vital role played by PARP-1 in HPV infection and carcinogenesis. Importantly, our data provide a mechanistic explanation for pharmacological PARP inhibition as an intriguing therapeutic opportunity for HPV(+) head and neck cancers.

Citation Format: Cyril S. Gary, Michael Hajek, Asel Biktasova, Andrew Sewell, Yarbrough G. Wendell, Natalia Issaeva. Functional interactions of HPV and PARP-1 in head and neck cancer [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Optimizing Survival and Quality of Life through Basic, Clinical, and Translational Research; April 23-25, 2017; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(23_Suppl):Abstract nr 68.
Abstract IA27: Current perspectives on the treatment of nasopharyngeal carcinoma (NPC)
Authors: Chan Anthony T. C.
Published: December 2017

70% of NPC patients present with UICC stages III and IV locoregionally advanced (LA) disease. A recently completed population screening study using plasma EBV DNA may change this picture.

For LA NPC, despite a high locoregional control rate after concurrent cisplatin-IMRT, the rate of distant metastases remains around 30%. Recent phase III studies adding induction chemotherapy have reported conflicting results, while studies adding adjuvant chemotherapy in unselected population have been negative. HKNPC 0502 and NRG HN001 are studies attempting to risk-stratify adjuvant therapy using post-RT plasma EBV DNA levels.

With the publication of exome and whole genome sequencing of NPC, precision targeted therapies and immunotherapies are being investigated. Early results using immune checkpoint inhibitors in patients with recurrent and metastatic disease are encouraging.

Citation Format: Anthony T. C. Chan. Current perspectives on the treatment of nasopharyngeal carcinoma (NPC) [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Optimizing Survival and Quality of Life through Basic, Clinical, and Translational Research; April 23-25, 2017; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(23_Suppl):Abstract nr IA27.
Self-Reports of Health before and during Imprisonment in Female Inmates
Authors: Alves Joana , Costa Maia Ângela
Published: December 2017

The health of female inmates has been described as more vulnerable than that of detained male and the overall female population. The purpose of this study is to describe health behaviors, history of diseases, health complaints, and health status of 232 incarcerated women. The women reported risk behaviors and unexpected health surveillance before their imprisonment. In prison, their tobacco use increased, drug consumption decreased and high rates of diseases, use of medicines, health complaints, and poor health status were found. The women’s perceptions of their current health, compared with the time period before prison, revealed different types of impact, with one-third reporting health improvements. These data suggest that women prisoners’ health and the prison’s impact on their health must be better studied in order to enhance the health intervention programs during imprisonment.
Of Cats and Men
Authors: Soler Nieves Pascual
Published: December 2017

The study analyzes the gender narratives linked to cats in Nestlé Purina Pet Care Company (NPPC) advertising. Out of the ten cat food products lines it markets, each offering from one to nine different formulas, nine are discussed. The focus is on dried food in pouch packages. It is argued that against the traditional association between cats and women, cat food advertising privileges masculine experiences. To support this claim, this article (a) analyzes the relationship between gender and food patterns; (b) probes the background for the perception of companion animals as projections of the human self; (c) examines representations of cats and food on selectNPPClabels; and (d) matches gender narratives with the new demographics ofUScat caregivers.