黄芩苷对结肠癌细胞凋亡的影响及作用机制

Effect of Baicalin on Apoptosis of Colon Cancer Cells and Its Mechanism

黄芩苷在多种肿瘤中具有较高的抗肿瘤活性,然而,其在结肠癌中的抗肿瘤作用尚不清楚。本研究考察了黄芩苷对人结肠癌细胞系RKO的增殖和凋亡的影响,并探讨了其相关作用机制。研究发现,黄芩苷可按照剂量依赖性方式和时间依赖性方式抑制结肠癌细胞增殖及集落形成能力。流式细胞术显示,与对照细胞相比,黄芩苷处理后的RKO细胞的凋亡率显著增加(5.6%vs 33.6%)。RT-PCR和Western blotting检测显示,黄芩苷处理可显著增加结肠癌RKO细胞中DKK1(Wnt信号通路的关键负调节因子)mRNA和蛋白表达水平。相反,黄芩苷处理则显著抑制结肠癌RKO细胞中c-Myc和β-catenin(DKK1的下游靶基因)的m RNA和蛋白表达。敲低DKK1后明显阻断了黄芩苷诱导的结肠癌细胞中DKK1蛋白的上调。此外,敲低DKK1逆转了黄芩苷对其下游基因c-Myc和β-catenin的抑制作用。黄芩苷处理后,结肠癌细胞中miR-217的表达显著下调。RT-PCR和Western blotting结果显示,下调miR-217显著促进DKK1的mRNA和蛋白表达。综上所述,本研究表明黄芩苷可通过抑制结肠癌细胞增殖并诱导细胞凋亡来发挥其抗肿瘤作用,黄芩苷通过激活结肠癌细胞中DKK1来抑制Wnt信号通路。此外,黄芩苷通过下调结肠癌细胞中miR-217的表达来上调DKK1的表达,从而起到抗癌作用。

Baicalin has high antitumor activity in various tumors.However,its antitumor effect in colon cancer is still unclear.This study investigated the effects of baicalin on the proliferation and apoptosis of human colon cancer cell line RKO and explored the relevant mechanisms of action.It was found that baicalin can inhibit colon cancer cell proliferation and colony forming ability in a dose-dependent and time-dependent manner.Flow cytometry showed a significant increase in apoptotic rate of baicalin-treated RKO cells compared to control cells(5.6%vs 33.6%).RT-PCR and Western blotting showed that baicalin treatment significantly increased m RNA and protein expression levels of DKK1,a key negative regulator of the Wnt signaling pathway,in colon cancer RKO cells.In contrast,baicalin treatment significantly inhibited mRNA and protein expression of c-Myc andβ-catenin(downstream target genes of DKK1)in colon cancer RKO cells.Knockdown of DKK1 significantly blocked up-regulation of DKK1 protein in baicalin-induced colon cancer cells.In addition,knockdown of DKK1 reversed the inhibitory effect of baicalin on its downstream genes c-Myc andβ-catenin.After treatment with baicalin,the expression of miR-217 was significantly down-regulated in colon cancer cells.RT-PCR and Western blotting showed that down-regulation of miR-217 significantly promoted DKK1 mRNA and protein expression.Taken together,this study demonstrates that baicalin exerts its anti-tumor effect by inhibiting colon cancer cell proliferation and inducing apoptosis.Baicalin inhibits Wnt signaling by activating DKK1 in colon cancer cells.In addition,baicalin can up-regulate the expression of DKK1 by down-regulating the expression of miR-217 in colon cancer cells,thus playing an anti-cancer role.