Department of Orthodontics, School of Stomatology, China Medical University, No. 117. Nanjing Bei Street, Heping District, Shenyang, Liaoning 110002, PR China.
Oncol Rep. 2011 Mar;25(3):729-37. doi: 10.3892/or.2010.1109. Epub 2010 Dec 14.
Metastatic squamous cell carcinoma of the head and neck (SCCHN) has been shown to express chemokine receptor 7 (CCR7), which activates phosphoinositide-3 kinase (PI3K) to promote invasion and survival of SCCHN cells. We hypothesized that Cdc42 might be involved in the CCR7-PI3K pathway. Adhesion assays, migration assays, immunofluorescence staining, Western blotting and immunohistochemical analysis were used to find whether Cdc42 can be activated by CCL19 (the CCR7 ligand) and its role in SCCHN. Results showed that CCL19 induced polarized localization of Cdc42 and actin polymerization in the leading edge of migrating cells. The level of activated membrane-bound Cdc42 was elevated, as measured by the GTPase activity pull-down assay. The increased membrane localization and membrane-bound activity of Cdc42 were abolished by CCR7 and PI3K inhibition, indicating the involvement of Cdc42 in the CCR7-PI3K cascade. Knockdown of Cdc42 by small interfering RNA (siRNA) led to significant reduction in the activation of Rac, filamentous actin (F-actin) accumulation as well as in the migration and invasion induced by CCL19. Taken together, our data indicate the important role played by Cdc42 in CCL19-induced migration and invasion of SCCHN cells.
头颈部转移性鳞状细胞癌（SCCHN）已被证明表达趋化因子受体 7（CCR7），其激活磷酸肌醇-3-激酶（PI3K）以促进 SCCHN 细胞的侵袭和存活。我们假设 Cdc42 可能参与 CCR7-PI3K 通路。我们使用粘附试验、迁移试验、免疫荧光染色、Western blot 和免疫组织化学分析来确定 Cdc42 是否可以被 CCL19（CCR7 配体）激活及其在 SCCHN 中的作用。结果表明，CCL19 诱导极化的 Cdc42 定位和细胞迁移前沿的肌动蛋白聚合。通过 GTPase 活性下拉测定测量，激活的膜结合 Cdc42 水平升高。CCR7 和 PI3K 抑制消除了 Cdc42 的膜定位和膜结合活性，表明 Cdc42 参与 CCR7-PI3K 级联反应。小干扰 RNA（siRNA）敲低 Cdc42 导致 Rac 的激活、丝状肌动蛋白（F-actin）积累以及 CCL19 诱导的迁移和侵袭显著减少。总之，我们的数据表明 Cdc42 在 CCL19 诱导的 SCCHN 细胞迁移和侵袭中发挥重要作用。
