亚硝酸钠对人肝癌细胞增殖与凋亡的影响

Effects of sodium nitrite on proliferation and apoptosis on human hepatocarcinoma cells

目的探讨亚硝酸盐对人肝癌细胞增殖和凋亡作用。方法用不同浓度的亚硝酸钠处理人肝癌SMMC-7721细胞不同时间,用MTT分析细胞增殖,荧光显微镜下观察细胞分裂指数和凋亡率,RT-PCR分析c-myc mRNA变化,Westernblot分析缺氧诱导因子-1α(HIF-1α)蛋白表达。结果亚硝酸钠诱导SMMC-7721细胞增殖和凋亡呈双相剂量效应,亚硝酸钠在低浓度时(20～200 mg.L-1),刺激细胞增殖,抑制细胞凋亡,在高浓度时(>800 mg.L-1),抑制增殖,促进凋亡。20～200 mg.L-1亚硝酸钠处理细胞可以明显增加c-myc mRNA和HIF-1α蛋白表达。结论亚硝酸钠在一定浓度范围内刺激SMMC-7721细胞增殖,但是超过一定剂量则诱导细胞凋亡。

Aim To investigate the effects of nitrite-induced proliferation and apoptosis on human hepatocarcinoma cells in vitro.Methods The proliferation and time-dependent response of SMMC-7221 cells was measured by MTT after exposing to variant dosages of sodium nitrite.Apoptosis and mitotic index were routinely evaluated by fluorescence microscopic assay.The reverse transcriptase-polymerase chain reaction（RT-PCR）was used to detect changes of c-myc mRNA.The protein expression of hypoxia-inducible factor-1α（HIF-1α）in cells was revealed by Western blot.Results At low dosage range of 20 mg·L-1 to 200 mg·L-1,the proliferation of SMMC-7721 cell was promoted while apoptosis was suppressed simultaneously.At higher dosage range（800 mg·L-1）,the scenario was reversed,which showed suppressed proliferation and enhanced apoptosis reciprocally.After being treated with 20～200 mg·L-1 sodium nitrite,SMMC-7721 cells expressed a high level of c-myc mRNA and HIF-1α protern significantly.Conclusions Sodium nitrite induced cell proliferation versus apoptosis in a biphasic dose-response fashion in human hepatocarcinoma SMMC-7721.