The tetraspanin CD9 modulates epidermal growth factor receptor signaling in cancer cells
The tetraspanin CD9 modulates epidermal growth factor receptor signaling in cancer cells
复制标题
DOI：
10.1002/jcp.21384
复制
发表时间：
2008-07-01
影响因子：
5.6
通讯作者：
Hayashi, Norio
中科院分区：
文献类型：
--
作者：
Murayama, Yoko;Shinomura, Yasuhisa;Hayashi, Norio
CD 9是四跨膜蛋白的一员，并且已经被证明参与多种细胞活动，如迁移、增殖和粘附。此外，已知CD 9可以与其他蛋白质缔合。在这里，我们证明了MKN-28细胞上的CD 9与表皮生长因子受体（EGFR）的物理和功能关联。双重免疫荧光染色和免疫沉淀证实了CD 9-EGFR和CD 9-β（1）整联蛋白的复合物形成，并且两种复合物共定位于细胞表面，特别是在细胞-细胞接触位点。抗CD 9单克隆抗体ALB 6诱导CD 9-EGFR和CD 9-β（1）整联蛋白呈点状或斑片状聚集模式。EGF刺激后的EGFR内化通过用ALB 6处理显著增强。转染pTJ/human EGFR/CD 9的肝癌细胞（HepG 2/CD 9）和中国仓鼠卵巢癌细胞（CHO-HER/CD 9）中，CD 9与EGFR结合。此外，CD 9的表达通过下调EGFR的表面表达而特异性地减弱CHO-HER/CD 9细胞中的EGFR信号传导。这些结果表明，CD 9可能具有减弱EGFR信号传导的重要作用。因此，CD 9不仅与EGFR相关，而且是一种新的调节因子，可能影响癌细胞中EGF诱导的信号传导。
CD9 is a member of the tetraspanins, and has been shown to be involved in a variety of cellular activities such as migration, proliferation, and adhesion. In addition, it has been known that CD9 can associate with other proteins. Here we demonstrated the physical and functional association of CD9 with epidermal growth factor receptor (EGFR) on MKN-28 cells. Double-immunofluorescent staining and immunoprecipitation demonstrated the complex formation of CD9-EGFR and CD9-beta(1) integrin, and that both complexes are colocalized on the cell surface especially at the cell-cell contact site. Anti-CD9 monoclonal antibody ALB6 induced a dotted or patch-like aggregation pattern of both CD9-EGFR and CD9-beta(1) integrin. The internalization of EGFR after EGF-stimulation was significantly enhanced by the treatment with ALB6. CD9 can associate with EGFR in hepatocellular carcinoma cells (HepG2/CD9) and Chinese hamster ovary cancer cells (CHO-HER/CD9), which were transfected with pTJ/human EGFR/CD9. Furthermore expression of CD9 specifically attenuated EGFR signaling in CHO-HER/CD9 cells through the down regulation of surface expression of EGFR. These results suggest that CD9 might have an important role that attenuates EGFR signaling. Therefore, CD9 not only associates EGFR but also a new regulator, which may affect EGF-induced signaling in cancer cells.