Abstract 2251: nrf2-keap1 axis molecular profile in small cell lung cancer cell lines

Abstract

Abstract The Keap1/Nrf2 pathway is a master regulator of antioxidants and cellular stress responses implicated in resistance of tumor cells against chemotherapeutic drugs. The link between molecular alterations of this pathway in Non Small Cell Lung Cancer (NSCLC) is well studied and appears to depend on several main factors including the existence of activating mutations in NFE2LE gene and/or loss of function mutations and methylation in the KEAP1 gene. At present, the data concerning the mechanism of alteration of Nrf2-Keap1 pathway in Small Cell Lung Cancer (SCLC) instead are almost incomplete and correlation analysis with therapeutic strategies targeting the molecular dysfunction of this pathway is ongoing. Here we present a comprehensive molecular alteration profile of the main partners of the Nrf2/keap1 axis in 12 SCLC cell lines by integrating data from SNP-Array analysis, immunofluorescence, mutation screening by direct sequencing, methylation by QMSP and expression analyses by RT-qPCR and western blotting. Our analyses confirm the global deregulation of Nrf2/Keap1 pathway in SCLC cell lines, showing an hypermethylation of the CpGs located into the P1 promoter region of the KEAP1 in 42% (5/12) of the cell lines, and a chromosomal amplification involving the NFE2LE gene locus (2q31.1) in two cell lines. Only one just described point mutation in the kelch-repeat 2 was observed in one of the cell line analysed. Our gene-alteration profile of SCLC cell lines provides new insights into the mechanism of deregulation of Nrf2-Keap1 detoxification pathway in this group of high grade neuroendocrine lung cancers, suggesting the NFE2LE gene amplification and the KEAP1 promoter hypermethylation as alternative mechanisms of dysfunctional Nrf2/Keap1 in SCLCs.Analyses on tumor tissues are ongoing to confirm these observations. Moreover, the provided full molecular data from cell lines will be useful for in vitro functional studies aimed to establish new combined therapeutic strategies in targeted cancer treatments of this aggressive lung tumor histotype. Citation Format: Lucia Anna Muscarella, Annamaria la Torre, Angelo Sparaneo, Orazio Palumbo, Clelia Tiziana Storlazzi, Teresa Balsamo, Domenico Trombetta, Fabio Pellegrini, Raffaela Barbano, Barbara Pasculli, Paolo Graziano, Montse Sanchez-cespedes, Maria Teresa Landi, Paola Parrella, Vito Michele Fazio. nrf2-keap1 axis molecular profile in small cell lung cancer cell lines. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2251. doi:10.1158/1538-7445.AM2014-2251