硒-甲基硒代半胱氨酸对肝癌HepG_2细胞的抑制作用

Inhibition on liver carcinoma cells HepG_2 by Se-methylselenocysteine

目的:研究硒-甲基硒代半胱氨酸(Se-methyl-selenocysteine,MSC)对肝癌HepG2细胞增殖及凋亡的影响,探讨其分子机制。方法:用不同浓度的MSC处理培养的HepG2细胞,镜下观察细胞的形态学变化,MTT法和流式细胞仪分别检测其对细胞生长和细胞周期的影响,软琼脂生长试验观察瘤细胞恶性表型的变化,并检测细胞周期蛋白D1(Cyclin D1)mRNA的表达和半胱氨酸蛋白酶-3(Caspase-3)的活性。结果:25μmol.L-1的MSC处理HepG2细胞24 h后,细胞生长受到明显抑制,出现S期阻滞和细胞凋亡,呈现浓度和时间依赖关系。软琼脂生长试验显示MSC抑制HepG2细胞在软琼脂上的生长能力。RT-PCR和Caspase-3的活性检测显示,25μmol.L-1MSC处理HepG2细胞244、8 h后,Cyclin D1 mRNA表达下降了38%和47%,而Caspase-3活性分别升高(39.61±6.65)%和(118.73±6.48)%;50μmol.L-1MSC处理HepG2细胞244、8 h后,Cyclin D1 mRNA表达下降了53%和82%,而Caspase-3活性分别升高(80.66±9.31)%和(152.67±7.95)%。结论:MSC抑制HepG2细胞增殖,诱导其凋亡,瘤细胞的恶性程度减弱,这种表型变化与Cyclin D1的表达减弱和Caspase-3的活性增强有关。

AIM： To study the effects of Se-methylselenocysteine （MSC） on the growth and apoptosis of human liver carcinoma cell line, HepG2 cells and the molecular mechanism of effects. METHODS： After HepG2 cells treated with various concentrations of MSC, survival and apoptosis were determined by MTT assay and light microscope, apoptosis and cell cycle were determined by flow cytometry. Malignant phenotype was determined by soft agarose growth assay. Cyclin D1 mRNA expression was determined by RT-PCR and Caspase-3 activity wasmeasured by Caspase-3 activity assay kit. RESULTS： After being treated with 25 μmol.L^-1 MSC for 24 h, the survival of HepG2 cells was decreased, a marked apoptosis and S phase arrest characteristic was observed in timeand dose- dependent manner. Soft agatose growth assay showed MSC inhibited HepG2 cells growth in soft agarose. RT-PCR and Caspase-3 assay showed that HepG2 cells treated with 25 μmol. L^-1 MSC for 24 and 48 hours, the expression of Cyclin D1 mRNA was down-regulated by 38% and 47%, while Caspase-3 activity was up-regulated by （39.61±6.65）%and （118.73±6.48）%. HepG^2 cells treated with 50μmol.L^-1 MSC for 24 and 48 h, the expression of Cyclin D1 mRNA was down-regulated by 53% and 82%, whereas Caspase-3 activity was up-regulated by （80.66 ± 9.31）% and （152.67 ± 7.95）%. CONCLUSION： MSC can inhibit the growth of HepG2 cells, and induce apoptosis and S phase arrest of HepG2 cells. The phenotype alterations of HepG2 cells might relate with inhibition of Cyclin D 1 expression and Caspase-3 activity by MSC in the cells.