0000000000377220
AUTHOR
Esra A. Akbay
Abstract C75: Overcoming KRAS/LKB1 mutant NSCLC resistance to BET bromodomain inhibitors with gemcitabine or Mcl-1 inhibition
Abstract The purpose of our study was to define a method and mechanism for overcoming the resistance of clinically relevant KRAS-mutant/LKB1-deficient NSCLC cells to the BET-bromodomain inhibitor JQ1. LKB1 (Serine/threonine kinase 11) is mutated with loss of function in conjunction with mutated KRAS in 7-10% of NSCLC. Importantly, KRAS-mutant/LKB1-deficiency is associated with tumor aggressiveness and poor survival in human patients as well as in genetically engineered mouse models. Indeed, although the BET bromodomain inhibitor JQ1 dramatically reduces tumor volume in KRAS mutant mice, it has little effect in KRAS-mutant/LKB1-deficient mice. BET bromodomain proteins are chromatin readers t…
Activation of the PD-1 Pathway Contributes to Immune Escape in EGFR-Driven Lung Tumors
Abstract The success in lung cancer therapy with programmed death (PD)-1 blockade suggests that immune escape mechanisms contribute to lung tumor pathogenesis. We identified a correlation between EGF receptor (EGFR) pathway activation and a signature of immunosuppression manifested by upregulation of PD-1, PD-L1, CTL antigen-4 (CTLA-4), and multiple tumor-promoting inflammatory cytokines. We observed decreased CTLs and increased markers of T-cell exhaustion in mouse models of EGFR-driven lung cancer. PD-1 antibody blockade improved the survival of mice with EGFR-driven adenocarcinomas by enhancing effector T-cell function and lowering the levels of tumor-promoting cytokines. Expression of m…
Targeting transcriptional addictions in small cell lung cancer with a covalent CDK7 inhibitor.
Small cell lung cancer (SCLC) is an aggressive disease with high mortality, and the identification of effective pharmacological strategies to target SCLC biology represents an urgent need. Using a high-throughput cellular screen of a diverse chemical library, we observe that SCLC is sensitive to transcription-targeting drugs, in particular to THZ1, a recently identified covalent inhibitor of cyclin-dependent kinase 7. We find that expression of super-enhancer-associated transcription factor genes, including MYC family proto-oncogenes and neuroendocrine lineage-specific factors, is highly vulnerability to THZ1 treatment. We propose that downregulation of these transcription factors contribut…
Abstract 1126: Efficacy of BET bromodomain inhibition in Kras-positive non-small cell lung cancer.
Abstract Amplification of MYC is one of the most common genetic alterations in lung cancer, contributing to a myriad of phenotypes associated with growth, invasion and drug resistance. Murine genetics has established both the centrality of somatic alterations of Kras in lung cancer, as well as dependency of Kras-dependent tumors on c-Myc function. Unfortunately, drug-like small-molecule inhibitors of KRAS and c-Myc have yet to be realized. The recent discovery in hematologic malignancies that bromodomain inhibition impairs MYC expression and MYC-dependent transcriptional function prompted the possibility of targeting KRAS-driven NSCLC with a potent, prototypical BET bromodomain inhibitor, J…
Interleukin-17A Promotes Lung Tumor Progression through Neutrophil Attraction to Tumor Sites and Mediating Resistance to PD-1 Blockade
Abstract Introduction Proinflammatory cytokine interleukin-17A (IL-17A) is overexpressed in a subset of patients with lung cancer. We hypothesized that IL-17A promotes a protumorigenic inflammatory phenotype and inhibits antitumor immune responses. Methods We generated bitransgenic mice expressing a conditional IL-17A allele along with conditional Kras G12D and performed immune phenotyping of mouse lungs, a survival analysis, and treatment studies with antibodies either blocking programmed cell death 1 (PD-1) or IL-6 or depleting neutrophils. To support the preclinical findings, we analyzed human gene expression data sets and immune profiled patient lung tumors. Results Tumors in IL-17:Kras…
Efficacy of BET Bromodomain Inhibition in Kras-Mutant Non–Small Cell Lung Cancer
Abstract Purpose: Amplification of MYC is one of the most common genetic alterations in lung cancer, contributing to a myriad of phenotypes associated with growth, invasion, and drug resistance. Murine genetics has established both the centrality of somatic alterations of Kras in lung cancer, as well as the dependency of mutant Kras tumors on MYC function. Unfortunately, drug-like small-molecule inhibitors of KRAS and MYC have yet to be realized. The recent discovery, in hematologic malignancies, that bromodomain and extra-terminal (BET) bromodomain inhibition impairs MYC expression and MYC transcriptional function established the rationale of targeting KRAS-driven non–small cell lung cance…
Abstract B290: Activation of the PD-1 pathway contributes to immune escape in EGFR-driven lung tumors.
Abstract The recent clinical success of therapeutic blockade of the immune checkpoint Programmed Death (PD)-1 in advanced lung cancer patients suggests that mechanisms of immune escape may contribute to lung tumor pathogenesis. We identified a correlation between Epidermal Growth Factor Receptor (EGFR) pathway activation and a gene signature indicative of immunosuppression manifested by upregulation of PD-1, PD-L1, cytotoxic T lymphocyte antigen-4 (CTLA-4) and multiple tumor-promoting inflammatory cytokines. Accordingly, we identified a decrease in the number of cytotoxic T cells and an increase in markers of T cell exhaustion in genetically engineered mouse models (GEMMs) of EGFR-driven lu…
D-2-hydroxyglutarate produced by mutant IDH2 causes cardiomyopathy and neurodegeneration in mice.
Mutations in isocitrate dehydrogenase 1 and 2 (IDH1/2) have been discovered in several cancer types and cause the neurometabolic syndrome D2-hydroxyglutaric aciduria (D2HGA). The mutant enzymes exhibit neomorphic activity resulting in production of D2-hydroxyglutaric acid (D-2HG). To study the pathophysiological consequences of the accumulation of D-2HG, we generated transgenic mice with conditionally activated IDH2R140Q and IDH2R172K alleles. Global induction of mutant IDH2 expression in adults resulted in dilated cardiomyopathy, white matter abnormalities throughout the central nervous system (CNS), and muscular dystrophy. Embryonic activation of mutant IDH2 resulted in more pronounced ph…