Cai T, Lei Q Y, Zha X L
Key Laboratory of Glycoconjugate Research, Shanghai Medical University, Shanghai 200032.
Shi Yan Sheng Wu Xue Bao. 2000 Dec;33(4):333-9.
In order to investigate whether TGF-beta 1 could rapidly regulate integrin induced signaling, we treated SMMC-7721 human hepatocellular carcinoma cells with human recombinant TGF-beta 1 for 10 min, and examined cell adhesion, integrin amount and FAK tyrosine phosphorylation. We used cell adhesion assay to estimate the affinity of alpha 5 beta 1 integrin with fibronectin, and analyzed the amount of integrin alpha 5 and beta 1 subunits by performing FACS analysis. Then western blot analysis was carried out to examine tyrosine phosphorylation level of FAK. Our results showed that TGF-beta 1 could rapidly attenuated cell adhesion onto Fn without changing the expression of alpha 5 beta 1 integrin, and at the meantime dephosphorylated FAK. It suggested that TGF-beta 1 rapidly regulated the activation of integrin, and stimulated FAK dephosphorylation, which might induce depolarization in SMMC-7721 hepatocellular carcinoma cells, then facilitates the detachment of tumor cells at early stages of migration.
为了研究转化生长因子β1（TGF-β1）是否能快速调节整合素诱导的信号传导，我们用人重组TGF-β1处理人肝癌细胞SMMC-7721 10分钟，并检测细胞黏附、整合素含量和黏着斑激酶（FAK）酪氨酸磷酸化。我们使用细胞黏附试验来评估α5β1整合素与纤连蛋白的亲和力，并通过流式细胞术分析整合素α5和β1亚基的含量。然后进行蛋白质免疫印迹分析以检测FAK的酪氨酸磷酸化水平。我们的结果表明，TGF-β1可快速减弱细胞在纤连蛋白上的黏附，而不改变α5β1整合素的表达，同时使FAK去磷酸化。这表明TGF-β1可快速调节整合素的激活，并刺激FAK去磷酸化，这可能诱导SMMC-7721肝癌细胞去极化，进而促进肿瘤细胞在迁移早期的脱离。
