水苏碱通过调控ACTG2蛋白表达抑制结肠癌生长

Stachydrine Inhibits the Growth of Colon Cancer by Regulating the Expression of ACTG2

目的探讨水苏碱(stachydrine)对结肠癌生长的影响及其分子作用机制。方法采用3-(4,5-二甲基吡啶-2-基)-5-(羧基甲氧基苯基)-2-(4-磺苯基)-2H-四唑(MTS)法研究水苏碱对人结肠癌细胞HCT116增殖的影响;构建人结肠癌HCT116裸小鼠细胞移植瘤模型,研究水苏碱对体内结肠癌生长的影响;免疫组化研究水苏碱对移植瘤中平滑肌肌动蛋白2(smooth muscle actin 2,ACTG2)蛋白表达的影响;构建ACTG2的siRNA质粒并转染HCT116细胞,采用小管形成实验研究ACTG2干扰以后水苏碱对结肠癌血管生成的影响;Western blot实验检测ACTG2干扰如何影响水苏碱对结肠癌细胞中血管内皮生长因子(vascular endothelial growth factor,VEGF)、碱性成纤维细胞生长因子(basic fibroblast growth factor,b FGF)、肿瘤坏死因子(tumor necrosis factor,TNF-α)及血小板衍生生长因子(platelet derived growth factor,PDGF)表达的作用。结果水苏碱处理HCT116细胞后,肿瘤细胞的体外增殖及体内生长均较对照组明显受到抑制;免疫组化结果显示,水苏碱能够显著抑制ACTG2蛋白的表达;干扰ACTG2后能够显著减弱水苏碱抑制肿瘤细胞血管生成的能力;进一步机制研究发现,水苏碱能够显著下调VEGF、bFGF、TNF-α及PDGF的表达,而干扰ACTG2则能够恢复上述血管生成因子的表达。结论水苏碱能够通过抑制ACTG2蛋白的表达抑制血管生成,进而发挥抑制结肠癌生长的能力。

OBJECTIVE To investigate the effect of stachydrine on tumor growth of colon cancer and its mechanisms.METHODS MTS was used to test the effect of stachydrine on proliferation of HCT116 colon cancer cell. HCT116 colon cancer xenograft model was used to detect the effect of stachydrine on tumor growth in vivo. Immunohistochemical was used to determine the effect of stachydrine on expression of smooth muscle actin 2 （ACTG2） in subcutaneous transplantation tumor. The transfection of ACTG2 siRNA into HCT116 cells was conducted to study the effect of ACTG2 intervene on tumor angiogenesis by tube formation experiment in colon cancer. The protein expression of VEGF, bFGF, TNF-α and PDGF after ACTG2 intervene were examined by Western blotting to explore the potential mechanisms of stachydrine on regulation of tumor angiogenesis.RESULTS Compared with the control group, the proliferation and growth of HCT116 colon cancer cells were significant inhibited by stachydrine in vitro and in vivo. Immunohistochemical showed that the expression of ACTG2 was significantly decreased by treatment with stachydrine. ACTG2 siRNA transfection could significantly decreased the inhibition effect of stachydrine on tumor angiogenesis. Mechanistic study found that stachydrine could inhibit the expression of VEGF, bFGF, TNF-α and PDGF, however, ACTG2 siRNA transfection could significantly reverse the expression of above mentioned angiogenesis-related factors.CONCLUSION Stachydrine could inhibit the growth of colon cancer by suppressing tumor angiogenesis, and such effect is dependent on ACTG2 expression.