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RESEARCH PRODUCT

Abstract 1126: Efficacy of BET bromodomain inhibition in Kras-positive non-small cell lung cancer.

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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, JQ1. Here, we report that NSCLC cells harboring the KRAS mutation are sensitive to JQ1 while NSCLC cells with concurrent mutant KRAS and LKB1 mutations are resistant to JQ1. In sensitive NSCLC models, JQ1 treatment results in the coordinate downregulation of the MYC-dependent transcriptional program. Furthermore, we evaluated JQ1 in transgenic mouse lung cancer models expressing mutant kras or concurrent mutant kras and lkb1. We found that JQ1 treatment produces significant tumor regression in mutant kras mice. As predicted, tumors from mutant kras and lkb1 mice did not respond to JQ1. Together, these data provide a compelling rationale for the study of BET bromodomain inhibitors in a common, genetically-defined population of patients with aggressive NSCLC. Citation Format: Takeshi Shimamura, Zhao Chen, Margaret Soucheray, Julian Carretero, Eiki Kikuchi, Jeremy H. Tchaicha, Yandhi Gao, Katherine A. Cheng, Travis J. Cohoon, Jun Qi, Esra A. Akbay, Alec C. Kimmelman, Andrew L. Kung, James E. Bradner, Kwok Kin Wong. Efficacy of BET bromodomain inhibition in Kras-positive non-small cell lung cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1126. doi:10.1158/1538-7445.AM2013-1126