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

Abstract

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 μM) 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.

Keywords::

• Apoptosis
• HeLa cell
• mitomycin C
• P-glycoprotein
• confocal microscopy

Acknowledgments

The authors gratefully acknowledge the gift of HeLa cells and reagents from Dr. T. Takaoka (Ph.D.) (Memorial Institute of Tissue Culture, Tochigi, Japan). This work was supported by grants (CSMC 82-B028, 83-NS-B-004, and 84-OM-B-017) from Chung Shan Medical University, Taiwan, ROC.