Involvement of mitochondrial events in SAHA-induced apoptosis.

(A) SAHA (5 μM) induced cleavage of Bid, a member of the Bcl-2 family. Cleaved Bid translocates to the mitochondria to promote apoptosis. (B) Overexpression of Bcl-2, which stabilizes the mitochondria and antagonizes the effects of Bid, protected MM.1S cells against SAHA-induced cell death. Cell survival (average ± SD) was quantified by MTT. Neo indicates neomycin, and refers to the empty vector that carries only the neomycin resistance gene but no Bcl-2 cDNA.