Apoptosis-based dual molecular targeting by INNO-406, a second-generation Bcr-Abl inhibitor, and ABT-737, an inhibitor of antiapoptotic Bcl-2 proteins, against Bcr-Abl-positive leukemia
Details
Publication Year 2007-09,Volume 14,Issue #9,Page 1667-1677
Journal Title
CELL DEATH AND DIFFERENTIATION
Publication Type
Journal Article
Abstract
Bcr-Abl is the cause of Philadelphia-positive (Ph+) leukemias and also constitutes their principal therapeutic target, as exemplified by dramatic effects of imatinib mesylate. However, mono-targeting of Bcr-Abl does not always achieve complete leukemia eradication, and additional strategies those enable complete elimination of leukemic cells are desired to develop. Here we demonstrate that INNO-406, a much more active Bcr-Abl tyrosine kinase inhibitor than imatinib, augments the activities of several proapoptotic Bcl-2 homology (BH)3-only proteins (Bim, Bad, Bmf and Bik) and induces apoptosis in Ph+ leukemia cells via Bcl-2 family-regulated intrinsic apoptosis pathway. ABT-737, an inhibitor of antiapoptotic Bcl-2 and Bcl-X-L, greatly enhanced the apoptosis by INNO-406, even in INNO-406-less sensitive cells with Bcr-Abl point mutations except T315l mutation. In contrast, co-treatment with INNO-406 and other pharmacologic inducers of those BH3-only proteins, such as 17-allylaminogeldanamycin, an heat shock protein-90 inhibitor, or PS-341, a proteasome inhibitor, did not further increase the BH3-only protein levels or sensitize leukemic cells to INNO-406-induced apoptosis, suggesting a limit to how much expression levels of BH3-only proteins can be increased by anticancer agents. Thus, double-barrelled molecular targeting for Bcr-Abl-driven oncogenic signaling and the cell protection by antiapoptotic Bcl-2 family proteins may be the rational therapeutic approach for eradicating Ph+ leukemic cells.
Publisher
NATURE PUBLISHING GROUP
Keywords
CHRONIC MYELOID-LEUKEMIA; CHRONIC MYELOGENOUS LEUKEMIA; TYROSINE KINASE INHIBITOR; BH3 MIMETIC ABT-737; IMATINIB MESYLATE; PROTEASOME INHIBITORS; BH3-ONLY PROTEINS; CHRONIC PHASE; CELL-DEATH; RESISTANCE
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Creation Date: 2007-09-01 12:00:00
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