Venetoclax is effective in small cell lung cancers with high BCL-2 expression

Purpose: Small cell lung cancer (SCLC) is an often-fatal neuroendocrine carcinoma usually presenting as extensive disease, carrying a 3% five-year survival. Despite notable advances in SCLC genomics, new therapies remain elusive, largely due to a lack of druggable targets. Experimental Design: We used a high-throughput drug screen to identify a venetoclax sensitive SCLC sub-population, and validated the findings with multiple patient-derived xenografts of SCLC. Results: Our drug screen consisting of a very large collection of cell lines demonstrated that venetoclax, an FDA-approved BCL-2 inhibitor, was found to be active in a substantial fraction of SCLC cell lines. Venetoclax induced BIM-dependent apoptosis in vitro and blocked tumor growth and induced tumor regressions in mice bearing high BCL-2-expressing SCLC tumors in vivo. BCL-2 expression was a predictive biomarker for sensitivity in SCLC cell lines and was highly expressed in a subset of SCLC cell lines and tumors, suggesting that a substantial fraction of SCLC patients could benefit from venetoclax. Mechanistically, we uncover a novel role for gene methylation that helped discriminate high BCL-2-expressing SCLCs. Conclusions: Altogether, our findings identify venetoclax as a promising new therapy for high BCL-2 expressing SCLCs.

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