人参皂苷Rg3对人胃癌细胞Pim-3及Bad凋亡蛋白表达的影响

Effect of ginsenoside Rg3 on the expression of Pim-3 and bad in human colon cancer cell lines

目的研究人参皂苷Rg3对人胃癌细胞株MKN28中Pim-3及磷酸化Bad蛋白pBad(Ser112),pBad(Ser136)表达的影响。方法用浓度为0,10,20,40和80μmol/L的人参皂苷Rg3处理MKN28细胞24h后。采用四甲基偶氮唑盐(MTT)方法检测人参皂苷Rg3对MKN28细胞增殖的抑制作用,倒置显微镜和流式细胞术观察人参皂苷Rg3对MKN28细胞凋亡的诱导作用,Westernblot方法检测经不同浓度人参皂苷Rg3处理后MKN28细胞中Pim-3,pBad(Ser112)和pBad(Ser136)的表达情况。结果10,20,40和80μmo1/L的人参皂苷Rg3对MKN28细胞增殖的抑制率分别为18.70,34.06,54.49,69.28%。10～80μmol/L的人参皂苷Rg3处理细胞呈现明显的凋亡形态学改变,80μmol/L人参皂苷Rg3处理MKN28细胞24h后,凋亡细胞占(12.23±2.1)%,处理组比正常对照组(3.28±1.7)%凋亡明显增加,差异有统计意义(P<0.01)。Bad总蛋白表达没有明显影响。pim-3和pBad(Ser112)的表达均随人参皂苷Rg3浓度的增加而逐渐减弱。pBad(Ser136)不表达。结论人参皂苷Rg3的抗癌活性与其调节Pim-3以及磷酸化Bad蛋白表达有关;Pim-3可磷酸化Bad抑制胃癌细胞的凋亡。

Objective To investigate the effects of Ginsenoside Rg3 on the expression of Pim-3 and Bad phosphorylated proteins：pBad（Ser112）,pBad（Ser136）in human gastric cancer cell line MKN28. Methods MKN28 cells were exposed to 0,10,20,40 and 80 Ixmol/L Ginsenoside Rg3 for 24 hours.The effect of Ginsenoside Rg3 on cell proliferation was measured by methyl thiazolyl tetra- zolium （MTT） assay, and the apoptosis of MKN28 cells was evaluated by invert microscope and flow cytometry.The expression of Pim-3 and pBad（Ser112） and pBad（ser136） were measured by Western blot.Results The inhibitory rate was 18.70,34.06,54.49,69.28% respectively,as MKN28 cells were exposed to 10,20,40 and 80 μmol/L Ginsenoside Rg3 for 24 hours.Typical morphological changes of apoptosis were induced by Ginsenoside Rg3 at the concentratations（10-80~mol/L） and flow cytometry showed the apoptosis rate was 3.28% in the normal control cells and 12.23% in the cells exposed to 80 μmol/L Ginsenoside Rg3 for 24 hours.The apoptosis rate in the cells exposed to 80 μmol/L Ginsenoside Rg3 for 24 hours was obviously higher than the control group, （P〈0.01）.Ginsenoside Rg3 had no marked influences on the total Bad protein expression. Pim-3 and pBad（Ser112） expression were both decreased with the increasing of Ginsenoside Rg3.The pBad（Ser136） was not expressed.Conclusion The anti-cancer action of GinsenosideRg3 may be associated with the decreased expression of Pim-3 and pBad（Ser112）;Pim-3 can phosphorylate Bad and inhibite the apoptosis of gastric tumor cells.