Abstract 2630: Inhibition of bone morphogenetic protein receptor 2 increases mitochondrial permeability and the downregulation of XIAP in lung cancer cells

Abstract

Abstract Bone morphogenetic protein receptor (BMP) inhibitors have been shown to induce death of lung cancer cells, which involves the downregulation of x-linked inhibitor of apoptosis protein (XIAP). XIAP is a potent inhibitor of executioner caspases that promotes resistance to many chemotherapeutic agents. The mechanism by which inhibiting BMP signaling downregulates XIAP has not been elucidated. We find that the BMP inhibitors JL5 and DMH2 downregulate XIAP and enhances cell death of TRAIL, Taxol, and AEG a Smac mimetic. JL5, which inhibits both type I and type II BMP receptors, enhances cell death of cancer therapeutics by decreasing the expression of XIAP, which leads to an increase in caspase activity. The downregulation of XIAP is mediated by the inhibition of the BMP type II receptor and not the BMP type I receptors. Knockdown of BMPR2 but not the BMP type I receptors increases mitochondrial permeability resulting in the release of cytochrome c and Smac/Diablo into the cytosol. These studies suggest that the inhibition of BMPR2 increases cytosolic Smac/Diablo that inhibits XIAP enhancing apoptotic cell death of cancer therapeutics. Citation Format: Rachel E. NeMoyer, Elaine Langenfeld, John Langenfeld. Inhibition of bone morphogenetic protein receptor 2 increases mitochondrial permeability and the downregulation of XIAP in lung cancer cells [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 2630.