Roles of Ca²⁺ in Apoptotic Volume Decrease in Nasopharyngeal Carcinoma Cells

ObjectiveTo study the role of calcium signaling pathway in apoptotic volume decrease (AVD) in nasopharyngeal carcinoma cells. Methods The apoptotic inducer Cisplatin was used to induce apoptotic volume decrease in poorly differentiated nasopharyngeal carcinoma cells (CNE-2Z cells). The software Q500MC was employed for acquisition of time-lapse images of living cells. Cell volume changes were obtained by analysis of the image analysis software Scion Image. ResultsExtracellular application of Cisplatin induced a decrease of cell volume. The Cisplatin-induced changes in cell volume were significant 10 min after exposed to bath solution containing Cisplatin. Depletion of calcium from the bath solution or extracellular applications of calcium channel blocker nifedipine delayed the initiation of AVD induced by Cisplatin, but not the appearance of AVD. There was no significant difference in AVD 50 min after applications of Cisplatin between control and cells treated with nifedipine or Ca2+-free bath solution. Conclusion The inflow of Ca2+ across the cell membrane may play an important role in activation of AVD at the early stage of apoptosis.