Direct Activation of BAX by BTSA1 Overcomes Apoptosis Resistance in Acute Myeloid Leukemia

The BCL-2 family protein BAX is a central mediator of apoptosis. Overexpression of anti-apoptotic BCL-2 proteins contributes to tumor development and resistance to therapy by suppressing BAX and its activators. We report the discovery of BTSA1, a pharmacologically optimized BAX activator that binds...

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Published in:	Cancer cell 2017-10, Vol.32 (4), p.490-505.e10
Main Authors:	Reyna, Denis E., Garner, Thomas P., Lopez, Andrea, Kopp, Felix, Choudhary, Gaurav S., Sridharan, Ashwin, Narayanagari, Swathi-Rao, Mitchell, Kelly, Dong, Baoxia, Bartholdy, Boris A., Walensky, Loren D., Verma, Amit, Steidl, Ulrich, Gavathiotis, Evripidis
Format:	Article
Language:	eng
Subjects:	Animals apoptosis Apoptosis - drug effects BAX BAX activator BCL-2 family bcl-2-Associated X Protein - chemistry bcl-2-Associated X Protein - physiology BH3 BTSA1 cell death Cell Line, Tumor Humans Hydrazones - pharmacology leukemia Leukemia, Myeloid, Acute - drug therapy Leukemia, Myeloid, Acute - pathology Mice mitochondria MOMP Protein Conformation Thiazoles - pharmacology Xenograft Model Antitumor Assays
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Summary:	The BCL-2 family protein BAX is a central mediator of apoptosis. Overexpression of anti-apoptotic BCL-2 proteins contributes to tumor development and resistance to therapy by suppressing BAX and its activators. We report the discovery of BTSA1, a pharmacologically optimized BAX activator that binds with high affinity and specificity to the N-terminal activation site and induces conformational changes to BAX leading to BAX-mediated apoptosis. BTSA1-induced BAX activation effectively promotes apoptosis in leukemia cell lines and patient samples while sparing healthy cells. BAX expression levels and cytosolic conformation regulate sensitivity to BTSA1. BTSA1 potently suppressed human acute myeloid leukemia (AML) xenografts and increased host survival without toxicity. This study provides proof-of-concept for direct BAX activation as a treatment strategy in AML. [Display omitted] •Small-molecule BTSA1 interacts potently and specifically with the BAX trigger site•BTSA1 triggers BAX activation leading to mitochondrial membrane permeabilization•BTSA1 promptly induces apoptosis in AML cell lines and patient samples•BTSA1 suppresses leukemia growth in vivo without toxicity to normal cells Reyna et al. develop BTSA1, a pharmacologically optimized BAX activator, and show that BTSA1-induced BAX activation effectively and selectively promotes apoptosis of acute myeloid leukemia cells. They further demonstrate that the BAX expression level and cytosolic conformation regulate the sensitivity to BTSA1.
ISSN:	1535-6108 1878-3686