PI3K/Akt信号与吴茱萸碱抑制人结肠癌细胞增殖的关系研究

Correlation of PI3K / Akt signaling pathway with anti-proliferative effect of evodiamine in colon cancer cells

目的研究吴茱萸碱(Evodiamine,Evo)对结肠癌Lo Vo细胞增殖的抑制作用及可能的分子机制。方法采用结晶紫染色分析Evo(0、0.5、1、2、4μmol/L)对Lo Vo细胞的增殖抑制作用;应用流式细胞术分析Evo(0、0.5、1、2μmol/L)对Lo Vo细胞凋亡的促进作用;Western blot法分析Evo(0、0.5、1μmol/L)对Lo Vo细胞中增殖细胞核抗原(proliferating cell nuclear antigen,PCNA)及Caspase-3蛋白表达水平的影响;利用缺氧诱导因子-1α(hypoxia inducible factor 1-alpha,HIF-1α)荧光素酶报告质粒检测Evo(0、0.5、1、2μmol/L)对HIF-1α转录活性的影响。采用Western blot法分析Evo(0、0.5、1、2μmol/L)对Lo Vo细胞中HIF-1α、Akt1/2和磷酸化Akt1/2蛋白水平的影响。结果与对照组相比,Evo明显抑制Lo Vo细胞增殖,下调PCNA蛋白水平,促进Lo Vo细胞凋亡;报告质粒统计结果显示,Evo呈浓度依赖性降低HIF-1α荧光素酶报告质粒活性(Evo为0.5μmol/L时,P<0.05;Evo为1μmol/L或2μmol/L时,P<0.01);Western blot检测结果显示,Evo能够明显降低HIF-1α蛋白水平,下调Akt1/2磷酸化水平。结论 Evo能够抑制Lo Vo细胞增殖并促进凋亡,其机制可能与Evo下调HIF-1α蛋白表达,抑制PI3K/Akt信号转导相关。

Objective To determine the anti-proliferative effect of evodiamine （Evo） on colon cancer cells and investigate the possible underlying mechanism. Methods LoVo cells were treated with 0, 0.5, 1, 2 and 4 μmol/L Evo, and then the anti-proliferation effect of Evo was assessed by crystal violet staining. Flow cytometry was used to determine the apoptosis of LoVo cells after the treatment of 0, 0.5, 1 and 2 μmol/L Evo. Western blotting was adopted to detect the expression of proliferating cell nuclear antigen （PCNA） and Caspase-3 in the cells treated with 0, 0.5 and 1 μmol/L Evo. Hypoxia inducible factor 1-alpha （HIF-α）-responsive firefly luciferase reporter was employed to measure the transcription activity of HIF-1α in 0, 0.5, 1 and 2 μmol/L Evo treated cells, and Western blotting was used to detect the expression of HIF-1α, Akt1/2, and p-Akt1/2 in the LoVo cells. Results Evo obviously inhibited the proliferation of LoVo cells, down-regulated the expression of PCNA and promoted the cell apoptosis. Luciferase reporter system indicated that Evo decreased the transcriptional activity of HIF-1α in a dose-dependent manner （Evo 0.5 μmol/L, P〈0.05; 1 or 2 μmol/L, P〈0.01）. Western blotting showed that the expression levels of HIF-1α and p-Akt1/2 were reduced after Evo treatment. Conclusion Evo inhibits the proliferation and promotes the apoptosis in LoVo cells, which may be due to its down-regulating HIF-1α and inhibiting the transconduction of PI3K/Akt signaling pathway.