Abstract
Resistance of chronic myeloid leukemia (CML) to tyrosine kinase inhibitor imatinib mesylate (IM) is most often due to point mutations in the Bcr-Abl fusion gene. T315I mutation (resulting in substitution of Ile for a Thr residue at the “gatekeeper” position 315) raises particular concern, because it also provides resistance to second-generation kinase inhibitors already approved for clinical use (nilotinib and dasatinib). Much effort is therefore focused on alternative molecular-based strategies. Previous studies proved that binding to 14-3-3 scaffolding proteins leads to cytoplasmic compartmentalization and suppression of proapoptotic and antiproliferative signals associated with Bcr-Abl protein kinase, hence contributing to leukemic clone expansion. Here we investigated the effect of 14-3-3 inhibition disruption on hematopoietic cells expressing the IM-sensitive wild type Bcr-Abl and the IM-resistant T315I mutation. Using a virtual screening protocol and docking simulations, we identified a nonpeptidic inhibitor of 14-3-3, named BV02, that exhibits a remarkable cytotoxicity against both cell types. c-Abl release from 14-3-3σ, promoting its relocation to nuclear compartment (where it triggers transcription of p73-dependent proapoptotic genes) and to mitochondrial membranes (where it induces the loss of mitochondrial transmembrane potential) combined with c-Abl enhanced association with caspase 9 (a critical step of sequential caspase activation further contributing to c-Abl pro-apoptotic function) has a prominent role in the effect of BV02 on Bcr-Abl-expressing cells. In conclusion, BV02 may be considered as a treatment option for CML and, in particular, for more advanced phases of the disease that developed IM resistance as a consequence of Bcr-Abl point mutations.
Footnotes
This study was supported by the University of Bologna [ex60% funds]; Ministero della Pubblica Istruzione [PRIN], BolognaAIL, Fondazione Monte dei Paschi di Siena; Asinex; Department of Radiation Oncology [Postdoctoral Grant (to M.M.)]; and Department of Biological Sciences, University of Calgary (Calgary, AB, Canada) [Postdoctoral Grant (to V.C.)].
Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
doi:10.1124/jpet.110.172536.
↵ The online version of this article (available at http://jpet.aspetjournals.org) contains supplemental material.
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ABBREVIATIONS:
- TK
- tyrosine kinase
- CML
- chronic myeloid leukemia
- IM
- imatinib mesylate
- BV02
- 2-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-ylcarbamoyl)terephthalic acid
- wt
- wild type
- JNK
- c-Jun NH2 terminal kinase
- MD
- molecular dynamics
- GA
- genetic algorithms
- MIFs
- molecular interactions fields
- PI
- propidium iodide
- IP
- immunoprecipitation
- CHAPS
- 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid
- FLICA
- fluorochrome-bound inhibitor of caspase.
- Received July 8, 2010.
- Accepted October 20, 2010.
- Copyright © 2011 by The American Society for Pharmacology and Experimental Therapeutics
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