Cleavage of DNA-PKcs and ATM induced by PS-341.

(A) PS-341-induces time- (upper panel) and dose- (lower panel) dependent DNA-PKcs cleavage in MM.1S cells. (B) Time-dependent DNA-PKcs cleavage is induced by PS-341 treatment in RPMI 8226 (upper panel) and U266 (lower panel) MM cell lines. (C) DNA-PKcs cleavage is also triggered by PS-341 treatment in purified patient MM cells. (D) PS-341 induces time- (upper panel) and dose- (lower panel) dependent ATM cleavage in MM.1S cells.