Abstract 2607: BPTF role in melanoma progression and BRAF resistance therapy

Abstract

Abstract Bromodomain PHD finger transcription factor (BPTF) plays an important role in chromatin remodeling, but its functional role in tumor progression is incompletely understood. Here we reveal new pro-oncogenic roles for BPTF in promoting tumor cell proliferation and resistance to targeted therapies. shRNA-mediated BPTF silencing suppressed the proliferative capacity (by 65.5%) and metastatic potential (by 66.4%) of melanoma cells. Elevated BPTF mean copy number greater than 3 was observed in 28 of 77 (36.4%) melanomas. BPTF overexpression predicted poor survival in a cohort of 311 melanoma patients (distant metastasis-free survival, p=0.03, and disease-specific survival p=0.008), and promoted resistance to BRAF inhibitors in melanoma cell lines. Metastatic melanoma tumors progressing on BRAF inhibitors contained low BPTF-expressing, apoptotic tumor cell sub-clones, indicating the continued presence of drug-responsive sub-clones within tumors demonstrating overall resistance to anti-BRAF agents. These studies demonstrate multiple pro-tumorigenic functions for BPTF, and identify it as a novel target for anti-cancer therapy. They also suggest the combination of BPTF targeting with BRAF inhibitors as a novel therapeutic strategy for melanomas with mutant BRAF. Citation Format: Altaf A. Dar, Shahana Majid, David de Semir, Vladimir Bezrookove, Mehdi Nosrati, Mohammed Kashani-Sabet. BPTF role in melanoma progression and BRAF resistance therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2607.