Data from Selective BCL-2 Inhibition by ABT-199 Causes On-Target Cell Death in Acute Myeloid Leukemia

Abstract

<div>Abstract<p>B-cell leukemia/lymphoma 2 (BCL-2) prevents commitment to programmed cell death at the mitochondrion. It remains a challenge to identify those tumors that are best treated by inhibition of BCL-2. Here, we demonstrate that acute myeloid leukemia (AML) cell lines, primary patient samples, and murine primary xenografts are very sensitive to treatment with the selective BCL-2 antagonist ABT-199. In primary patient cells, the median IC<sub>50</sub> was approximately 10 nmol/L, and cell death occurred within 2 hours. Our <i>ex vivo</i> sensitivity results compare favorably with those observed for chronic lymphocytic leukemia, a disease for which ABT-199 has demonstrated consistent activity in clinical trials. Moreover, mitochondrial studies using BH3 profiling demonstrate activity at the mitochondrion that correlates well with cytotoxicity, supporting an on-target mitochondrial mechanism of action. Our protein and BH3 profiling studies provide promising tools that can be tested as predictive biomarkers in any clinical trial of ABT-199 in AML.</p><p><b>Significance:</b> Although targeting BCL-2 has largely been investigated in lymphoid cancers, we present preclinical results of targeting BCL-2 in AML. These results support clinical testing of the small-molecule BCL-2 antagonist ABT-199 in AML, accompanied by testing of predictive biomarkers used in this study. <i>Cancer Discov; 4(3); 362–75. ©2013 AACR</i>.</p><p>See related commentary by Hockenbery, p. 278</p><p>This article is highlighted in the In This Issue feature, p. 259</p></div>