ABT-737S1002

ABT-737 shows low activity to Bcl-B and no effects to Mcl-1 and BFL-1. ABT-737 is sensitive to HL60, KG1 and NB4 cells with IC50 of 50 nM, 80 nM and 80 nM, respectively. ABT-737 induces apoptosis in HL60 cells, which due to decreased Bcl-2/Bax heterodimerization and has no effect on cell cycle distribution. ABT-737 also induces cytochrome c release from purified mitochondria and promotes conformational changes in Bax that are associated with apoptosis. ^[1] Resistant cells (Hela and MCF-7) can be sensitized to ABT-737 by approaches that down-regulate, destabilize, or inactivate Mcl-1. ABT-737 also causes Bax/BAK-dependent cytochrome c release only when Mcl-1 has been neutralized. ^[2] ABT-737 displaces Bim from Bcl2's BH3-binding pocket, allowing Bim to activate Bax, induce mitochondrial permeabilization, and rapidly commit the primary chronic lymphocytic leukemia (CLL) cells to death. ^[3] Knockdown of Mcl-1 with siRNA sensitizes two resistant SCLC cell lines H196 and DMS114 to ABT-737 by enhancing the induction of apoptosis. Likewise, up-regulation of Noxa sensitizes H196 cells to ABT-737. ABT-737 inhibits many SCLC cell lines including NCI-H889, NCI-H1963, NCI-H1417, NCI-H146 and etc. Bcl-2 and Noxa may contribute mechanistically to the cellular response to ABT-737 in NCI-H146 cells. ^[4] A recent study shows that ABT-737 significantly induces apoptosis in HTLV-1 infected T-cell lines as well as in fresh ATLL cells. ^[5]