Apoptotic death mode of mitomycin C-treated HeLa cells and cellular localization of mitomycin C-induced P-glycoprotein.

Mitomycin C (MMC) is an active antineoplastic agent and is suggested to induce apoptosis in a caspase- dependent manner in human gastric, bladder, and breast cancer cells. In this study, the death mode of human cervical cancer cells (HeLa) induced by MMC and the cellular localization of MMC-induced P-glycoprotein (P-gp) were investigated. The results of caspase-3 activity, Annexin V binding, and DNA fragmentation suggested that the degree of caspase-dependent apoptosis induced by MMC was in a dose-, but not time-dependent, manner. Further, in low-dose (0.0299 microM) and long-term (2 months) treatment with MMC, P-gp is itself extruded from the cells and colocalized with nuclear DNA and the overexpression was achieved.