氯通道在三氧化二砷诱导鼻咽癌细胞凋亡中的作用

Role of chloride channels on apoptosis of CNE-2Z cells induced by arsenic trioxide

目的:探讨氯通道在三氧化二砷(arsenic trioxide,As_2O_3)诱导人鼻咽癌CNE-2Z细胞凋亡中的作用。方法:采用流式细胞术检测CNE-2Z细胞经As_2O_3作用24及48 h的凋亡率;应用膜片钳技术记录As_2O_3激活的细胞膜电流,并分析其电流特性;采用流式细胞术检测氯通道阻断剂DIDS对As_2O_3诱导的CNE-2Z细胞凋亡的抑制作用。结果:(1)5μmol/L As_2O_3能够时间依赖性地诱导的CNE-2Z细胞凋亡;(2)CNE-2Z细胞外灌流含5μmol/L As_2O_3的等渗溶液能够激活一个具有外向整流特征的电流,激活的电流无明显的时间及电压依赖性失活,翻转电位接近氯平衡电位;(3)As_2O_3激活的电流能够被氯通道阻断剂DIDS和NPPB完全抑制,细胞外灌流47%的高渗溶液能够完全抑制As_2O_3激活的电流;(4)氯通道阻断剂DIDS能够抑制As_2O_3诱导的CNE-2Z细胞凋亡。结论:As_2O_3可以激活CNE-2Z细胞的容积敏感性氯通道。氯通道在As_2O_3诱导的CNE-2Z凋亡中发挥重要作用。

AIM： To investigate the role of chloride channels in the apoptosis of human poorly differentiated nasopharyngeal carcinoma CNE-2Z cells induced by arsenic trioxide（ As2O3）. METHODS： The apoptotic rates of CNE-2Z cells induced by As2O3 for 24 h or 48 h were monitored by flow cytometry. The technique of whole-cell patch clamp was used to record the currents activated by As2O3 in the CNE-2Z cells. The inhibition of As2O3-induced apoptosis by chloride channel blocker DIDS in the CNE-2Z cells was analyzed by flow cytometry.RESULTS： As2O3 at 5 μmol/L induced apoptosis of CNE-2Z cells in time-dependent manner. The currents with outward rectification were activated when the cells were exposed to 5 μmol/L As2O3. No obvious time-and voltage-dependent inactivation of the currents was observed. The reverse potential of the currents was close to the equilibrium potential for chloride. The activated currents were inhibited by the chloride channel blockers NPPB and DIDS. The 47% hypertonic solution inhibited the activated currents completely.Chloride channel blocker DIDS inhibited the apoptosis of CNE-2Z cells induced by As2O3. CONCLUSION： As2O3 activates volume-sensitive chloride channels,and chloride channels may play an important role in the apoptosis of CNE-2Z cells induced by As2O3.