氯通道在华蟾酥毒基诱导的鼻咽癌细胞凋亡中起重要作用

Roles of chloride channels in apoptosis induced by cinobufagin in nasopharyngeal carcinoma cells

目的:研究氯离子通道在华蟾酥毒基(CBG)诱导低分化鼻咽癌CNE-2Z细胞凋亡和凋亡性容积减小中的作用。方法:实验设立空白对照组、CBG高、中、低剂量组及CBG与氯通道阻断剂NPPB联合作用组。Hoechst 33342染色检测细胞的凋亡率,活细胞图像分析法检测细胞容积变化,全细胞膜片钳法记录氯电流。结果:(1)CBG浓度依赖性诱导鼻咽癌细胞凋亡,高剂量CBG(8μmol/L)诱导的细胞凋亡率为43.2%;(2)CBG可诱导细胞产生凋亡性容积减小,在CBG作用早期(50 min),细胞容积减小约9.9%。(3)CBG可激活氯通道,产生一个无明显外向优势的氯电流。(4)氯通道阻断剂NPPB可抑制CBG诱导的细胞凋亡、凋亡性细胞容积减小和氯电流。NPPB对CBG诱导的细胞凋亡和凋亡性容积减小的抑制率分别达80.1%和74.8%。结论:以上结果提示CBG可能通过激活氯通道而诱导细胞凋亡,氯通道的激活可能在CBG抗肿瘤机制中起重要作用。

AIM： To investigate the roles of chloride channels in the apoptosis and apoptotic volume decrease（AVD） induced by cinobufagin in nasopharyngeal carcinoma CNE-2Z cells.METHODS： Five experimental groups in this study were set up,including control group,cinobufagin groups treated with low,medium or high concentration of cinobufagin alone,and the combination group treated with cinobufagin and the chloride channel blocker 5-nitro-2-（3-phenylpropylamino）-benzoate（NPPB）.Apoptotic rates were detected by Hoechst 33342 staining and the volume changes were measured by the method of time-lapse live cell imaging.The patch clamp technique was used to record whole-cell chloride currents.RESULTS： Cinobufagin induced apoptosis of nasopharyngeal carcinoma cells in a concentration-dependent manner.The apoptotic rate was 43.2% in the cells treated with cinobufagin at high concentration（8 μmol/L）.An AVD was observed in the cells treated with cinobufagin.Cinobufagin decreased the cell volume by 9.9% in 50 min and activated a chloride current which did not show significant outward rectification.The chloride channel blocker NPPB inhibited the cinobufagin-induced apoptosis,AVD and chloride currents.NPPB decreased the cinobufagin-induced apoptosis and AVD by 80.1% and 74.8%,respectively.CONCLUSION： Our findings suggest that cinobufagin induces apoptosis by activation of chloride channels,which may play an important role in the anti-tumour action of cinobufagin.