EGF/PI3K信号传导调控骨桥蛋白在肝癌HepG2细胞中的表达

EGF/PI3K signaling pathway regulates the expression of osteopontin in liver cancer HepG2 cells

目的 检测生长因子受体激活后骨桥蛋白在肝癌细胞株HepG2中表达的变化规律 ,并探讨这一变化的信号传导途径。方法 利用RNA酶保护性分析、蛋白质印迹技术检测HepG2在表皮生长因子 (EGF)刺激前后骨桥蛋白的表达 ;并用Wortmannin特异性地阻断磷脂酰肌醇 3激酶(PI3K)信号通道 ,以观察骨桥蛋白表达的变化是否与PI3K信号传导途径有关。结果 在无血清培养条件下 ,骨桥蛋白在HepG2中少量表达 ,而EGF能诱导其表达 ,且呈剂量依赖性及时间依赖性。先用Wortmannin预处理HepG2细胞再用EGF诱导 ,能阻断骨桥蛋白的表达。结论 EGF通过PI3K信号通道诱导转移相关基因 骨桥蛋白的表达 ,提示可通过干预该途径中的某些关键基因来阻断骨桥蛋白的产生 ,从而抑制肝癌的转移。

Objective To investigate the effect of epidermal growth factor (EGF) on the expression of osteopontin (OPN) in liver cancer HepG2 cells. Methods Human liver caner cells of HepG2 line were cultured in medium without bovine serum. EGF was added. Another cells were pretreated with specific phosphatidylinositol 3 (PI3) inhibitor Wortmannin and then added with EGF. HepG2 cell were collected. RNase prote4ction assay and Western blotting were used to examine the expression of OPN in the HepG2 cells. Results HepG2 cells cultured in the bovine serum free medium expressed very low level of OPN. EGF increased the expression of OPN mRNA and protein in a dose- and time-dependent manners. Pretreatment of Wortmannin significantly reduced the EGF-induced OPN expression. Conclusion EGF increases the OPN expression, possibly through PI3 signaling pathway. It is possible to block the synthesis of OPN through manipulating several target genes, thus inhibiting the metastasis of liver cancer.