褪黑素通过调控EZH2表达增强食管癌细胞对5⁃氟尿嘧啶的敏感性

Melatonin enhances the sensitivity of esophageal cancer cellsto 5⁃fluorouracil by regulating EZH2 expres⁃sion

目的探讨褪黑素(melatonin,MLT)协同5⁃氟尿嘧啶(5⁃fluorouracil,5⁃FU)抑制食管癌细胞的作用及其分子机制。方法采用不同浓度的褪黑素和5⁃FU处理人食管癌EC⁃9706和EC⁃109细胞;通过检测细胞活性、侵袭迁移、细胞凋亡和蛋白表达来探讨褪黑素对5⁃FU化疗敏感性的影响,进一步探索其可能的作用机制。通过荷瘤实验探讨褪黑素和5⁃FU协同抗肿瘤的作用。结果褪黑素对EC⁃9706和EC⁃109细胞活力的抑制呈剂量依赖性;与空白对照组相比,褪黑素能够降低EC⁃9706和EC⁃109细胞的侵袭和迁移能力(P<0.01),增加细胞的凋亡率(P<0.01)。与单独褪黑素和5⁃FU药物处理组比较,褪黑素和5⁃FU联合组显著降低食管癌细胞的增殖、侵袭和迁移,增加细胞凋亡(P<0.01)。同时,与单独褪黑素和5⁃FU药物处理组比较,褪黑素和5⁃FU联合组显著降低EZH2的表达。过表达EZH2能够逆转褪黑素和5⁃FU对EC⁃9706细胞的影响(P<0.01)。此外,与单独5⁃FU给药组比较,褪黑素和5⁃FU联合给药显著抑制裸鼠体内肿瘤的生长(P<0.01)。结论褪黑素和5⁃FU协同抑制EZH2的表达、促进食管癌细胞凋亡,提高5⁃FU对食管癌细胞的敏感性、抑制肿瘤生长。

Objective To investigate the inhibitory effect of melatonin in conjunction with 5⁃fluorouracil and its molecular mechanism in esophageal cancer.Methods Human esophageal carcinoma EC⁃9706 and EC⁃109 cells were treated with MLT and 5⁃FU at different concentrations.The effects of MLT on the chemotherapy sensitivi⁃ty of 5⁃FU were investigated by detecting cell activity,invasion,migration,apoptosis and protein expression,and the possible mechanism was further explored.The synergistic antitumor effect of MLT and 5⁃FU was investigated by tumor⁃bearing experiment.Results MLT inhibited the activity of EC⁃9706 and EC⁃109 cells in a dose⁃dependent manner.Compared with blank controls,melatonin reduced the invasion and migration of EC⁃9706 and EC⁃109 cells(P<0.01),but increased the apoptosis rate(P<0.01).Compared with MLT and5⁃FU alone group,the combinational use of melatonin and 5⁃FU significantly reduced the proliferation,invasion,migration and apoptosis of esophageal carcinoma cells(P<0.01).Meanwhile,compared with MLT and5⁃FU alone,the combinational use of melatonin and 5⁃FU significantly reduced EZH2 expression,and overexpression of EZH2 reversed the effects of MLT and 5⁃FU on EC⁃9706 cells(P<0.01).In addition,MLT and 5⁃FU combined administration significantly inhibited the growth of esophageal cancer in nude mice compared with 5⁃FU alone(P<0.01).Conclusion The combinational use of melatonin and 5⁃FU promotes apoptosis by inhibiting the expression of EZH2,thus improving the sensitivity of 5⁃FU to esophageal carcinoma cells and inhibiting tumor growth.