吉非替尼通过抑制EGFR/Akt信号通路特异性抑制平滑肌细胞增殖

Special inhibition of smooth muscle cell proliferation by gefitinib via EGFR/Akt pathway

【摘要】 目的：探讨表皮生长因子受体 （epidermal growth factor receptor，EGFR）抑制剂吉非替尼对平滑肌细胞（smooth muscle cells, VSMC） 和内皮细胞 （ndothelial cells, EC） 增殖的影响，以及对EGFR和Akt蛋白表达及磷酸化的影响。方法：将大鼠VSMC及EC置于含0.01～10 μmol？L的吉非替尼的培养基中培养24～72 h，以MTT法测定细胞增殖的抑制率。Western-blot检测EGFR及磷酸化EGFR（p-EGFR）、Akt及磷酸化Akt（p-Akt）蛋白水平。结果：MTT结果显示，吉非替尼抑制VSMC增殖呈时间和浓度依赖性，而吉非替尼对EC增殖的抑制作用明显低于紫杉醇；Western-blot结果显示VSMC中EGFR（1.07±0.13）表达与EC（0.58±0.05）相比明显增多（P〈0.01），而吉非替尼可明显抑制VSMC中EGFR及Akt蛋白的磷酸化。结论：类似紫于杉醇，吉非替尼可抑制VSMC增殖，而对EC的细胞毒性作用明显低于紫杉醇，其机制可能是通过抑制EGFR及Akt蛋白磷酸化来实现的。

OBJECTIVE To investigate effects of gefitinib, an epidermal growth factor receptor （EGFR） inhibitor, against proliferation of smooth muscle cells and endothelial cells, and effects against expression and phosphorylation of EGFR/Akt pro- tein. METHODS Rat smooth muscle cells and endothelial cells were cultured in medium with 0. 01 - 10μmol.L^-1 of gefitinib for 24-72h. MTT assay was used to test inhibition of cell proliferation. Western blot was used to detect expression of EGFR and phosphorylated EGFR （p-EGFR）, Akt and phosphorylated Akt （p-Akt）. RESULTS MTT showed inhibiting effects of gefitinib against smooth muscle cell proliferation in a time and concentration dependent manner. Inhibition rate of gefitinib on endothelial ceil proliferation was significantly lower than paclitaxel. Western blot showed expression of EGFR in smooth muscle cells （1.07 - 0. 13） was more obvious than endothelial cells （0. 58 ± 0. 05）, and gefitinib inhibited expression of EGFR and phosphorylated Akt in smooth muscle cells. CONCLUSION Compared to paclitaxel, gefitinib can inhibit proliferation of smooth muscle cells, while eytotoxic effects of gefitinib on endothelial ceils are significantly lower, and the mechanism may be realized by inhibiting phosphorylation of EGFR and Akt.