IFN-αinduces cell death in MM lines by activation of caspases. (A) IFN-α stimulation induces apoptosis in MM cell lines. IFN-α (2000 U/mL) activates caspase-3 in the MM cell lines H929 and 8226, and inhibitor of caspase-3 blocks IFN-α–induced caspase-3 activity and cell death. (B) IFN-α (2000 U/mL) induces apoptosis in the MM cell lines H929 and 8226 as assayed by internucleosomal fragmentation using a TdT assay. Data are presented as average of 3 independent experiments (± SD).