光敏化促进姜黄素诱导人胃癌MGC-803细胞凋亡

目的: 探讨光敏化促进姜黄素诱导人胃癌MGC-803细胞凋亡及其机制。方法: 用MTT法检测光敏化姜黄素对胃癌MGC-803细胞株的增殖抑制率,Hoechst 33258荧光染色观察细胞核形态的变化,流式细胞术检测细胞的凋亡率、线粒体膜电位、细胞内活性氧和Ca²⁺;比色法检测caspase-3、8和9酶活性;Western blotting分析细胞色素C、Bcl-2、Bax和热休克蛋白70(HSP70)水平。结果: 单纯姜黄素(5.0μmol/L)对MGC-803细胞增殖抑制率为(29.74±2.30)%,在光学显微镜下可见部分凋亡细胞,凋亡率为(12.54±1.75)%。而光敏化姜黄素组细胞增殖抑制率则为(44.93±3.61)%,在光学显微镜下能见明显细胞核形态改变,染色质凝集,凋亡小体形成,凋亡率为(26.58±2.67)%,细胞周期主要阻滞于G₀/G₁期。光敏化姜黄素显著降低线粒体膜电位,显著增加细胞色素C、细胞内活性氧和Ca²⁺以及caspase-3、8和9酶活性,与单纯姜黄素组比较,差异显著(P<0.01)。Western blotting结果显示光敏化姜黄素同时显著抑制Bcl-2和HSP70蛋白表达水平。结论: 光敏化姜黄素通过Bcl-2和线粒体途径增强其诱导胃癌MGC-803细胞凋亡的作用。

Photoactivation promotes curcumin to induce apoptosis of human gastric cancer MGC-803 cells

AIM: To investigate the effect of photoactivated curcumin on apoptosis of human gastric cancer MGC-803 cells.METHODS: The effect of photoactivated curcumin on the growth inhibitory rate of gastric cancer MGC-803 cells was detected by MTT assay.The changes of nuclear morphology were observed under optical microscope with Hoechst 33258 fluorescent staining.The apoptotic rate,mitochondrial membrane potential,intracellular reactive oxygen species and Ca2+ level was determined by flow cytometry.The activity of caspase-3,caspase-8 and caspase-9 was detected by colorimetry.The protein levels of cytochrome C,Bcl-2,Bax and heat-shock protein 70(HSP70) were analyzed by Western blotting.RESULTS: The growth inhibitory rate of MGC-803 cells treated with curcumin at concentration of 5.0 μmol/L was(29.74±2.30)%.Some apoptotic cells were observed under optical microscope,and the apoptotic rate was(12.54±1.75)%.The growth inhibitory rate of MGC-803 cells treated with photoactivated curcumin was(44.93±3.61)%.Significant morphological changes in the nucleus,such as chromatin condensation and apoptotic body formation,were observed under light microscope,and the apoptotic rate was(26.58±2.67)%.The cell cycle was arrested at G0/G1 phase.Compared with curcumin group,significant reduction in mitochondrial membrane potential,significant increase in cytochrome C,intracellular reactive oxygen species,Ca2+ level and the activity of caspase-3,caspase-8 and caspase-9 were observed in photoactivated curcumin group(P<0.01).Photoactivated curcumin also significantly inhibited the protein expression of Bcl-2 and HSP70 in the cells.CONCLUSION: Photoactivated curcumin enhances the apoptosis of gastric cancer MGC-803 cells by inhibiting Bcl-2 expression and promoting the mitochondrial pathway.