血管内皮生长因子体外刺激卵巢癌细胞株信号转导及转录激活因子3磷酸化的研究

Phosphorylation of signal transducer and activators of transcription 3 induced by vascular endothelial growth factor in ovarian carcinoma cell line in vitro

目的 观察血管内皮生长因子 (VEGF)刺激上皮性卵巢癌细胞株Caov 3(Caov 3细胞 )后 ,信号转导及转录激活因子 3(STAT3)磷酸化的变化 ,探讨磷酸化的STAT3是否参与Caov 3细胞VEGF的信号转导。方法 采用免疫细胞化学和蛋白印迹的方法 ,测定体外不同浓度VEGF刺激Caov 3细胞STAT3磷酸化的水平 ;并观察能与VEGF受体 2 (VEGFR2 )特异性结合的短肽 ,对VEGF刺激STAT3磷酸化的阻断作用。结果 VEGF能够刺激Caov 3细胞的STAT3磷酸化。采用免疫细胞化学和蛋白印迹方法 ,浓度为 5 0ng/ml的VEGF刺激Caov 3细胞 30min后 ,Caov 3细胞STAT3磷酸化水平均增高 ,分别为 2 2 0± 0 2 8和 1 37± 0 17,与VEGF浓度为 0ng/ml时Caov 3细胞STAT3磷酸化的水平 (分别为 0 5 6± 0 15和 0 4 7± 0 19)比较 ,差异有极显著性 (P <0 0 0 1) ;并且STAT3磷酸化蛋白发生向细胞核内移位。VEGF刺激Caov 3细胞 6 0min后 ,Caov 3细胞STAT3磷酸化的水平 (分别为 0 95± 0 18和 0 6 6± 0 2 0 ) ,与刺激 30min时Caov 3细胞STAT3磷酸化的水平 (分别为 2 0 3± 0 17和 1 5 8±0 2 3)比较 ,差异有极显著性 (P <0 0 0 1)。与VEGFR2特异性结合的 80 μmol/L的短肽能有效抑制VEGF诱导STAT3的磷酸化水平。结论 VEGF在体外可诱导Caov 3?

Objective To observe phosphorylation of signal transducer and activators of transcription 3(STAT3) in Caov-3 induced by vascular endothelial growth factor(VEGF), and to investigate molecular mechanisms of the effect of VEGF on ovarian carcinoma cells. Methods The expressions of phosphorylated STAT3 in Caov-3 induced by VEGF were detected by immunocytochemistry and Western blot methods. Furthermore, the relationship between STAT3 phosphorylation and VEGF stimulation in ovarian carcinoma cells was investigated using a peptide which could specifically bind VEGFR2 and thus block the binding of VEGF to its receptors. Results With VEGF stimulation, the expressions of phosphorylated STAT3 were significantly higher than those without VEGF stimulation in Caov-3. And 50 ng /ml was the effective dose resulting in a significant increase of phosphorylated STAT3(2.20±0.28/1.37±0.17)compared to 0 ng/ml(0.56±0.15/0.47±0.19)(P<0.001). Translocation into nuclei of activated STAT3 occurred after 30 min,while STAT3 phosphorylation decreased after 60 min of stimulation(0.95±0.18/0.66±0.20). A small peptide specific for VEGFR2, blocked the increase of STAT3 phosphorylation induced by VEGF in a dose dependent manner and 80 μmol/L was the effective dose(P<0.001). Conclusions VEGF could induce STAT3 phosphorylation and translocation into nuclei of activated STAT3 in Caov-3, and the small peptide could effectively inhibit these effects of VEGF. It suggests that STAT3 participates in the VEGF signal transduction mediated by VEGFR2 in ovarian carcinoma cells.