Obatoclax

Obatoclax binds to members of the Bcl-2 protein family, preventing the binding of these anti-apoptotic proteins to the pro-apoptotic proteins Bax and Bak and so promoting the activation of the apoptotic pathway in Bcl-2-overexpressing cells. The Bcl-2 family of proteins (bcl-2, bcl-xl, bcl-w, and Mcl-1) are overexpressed in a wide variety of cancers, including those of the lymphatic system, breast, lung, prostate, and colon. Obatoclax prevents the interaction of these pro-survival proteins with Bax or Bak, thereby inducing apoptosis with up-regulation of Bim, induced cytochrome c release, and activation of caspase-3. Obstoclax also induces autophagy in mouse embryo fibroblasts and in HeLa cells.This compound inhibits the growth of cancer cell lines and primary cancer isolates. Obatoclax enhances cytarabine-induced apoptosis by enhancing DNA DSBs. This novel mechanism provides compelling evidence for the clinical use of BH3 mimetics in combination with DNA-damaging agents in AML and possibly a broader range of malignancies.