Koh Sung Ae, Kim Min Kyoung, Lee Kyung Hee, Kim Sang Woon, Kim Jae-Ryong
Department of Hematology-Oncology, College of Medicine, Yeungnam University, 317-1 Daemyung-Dong, Taegu, 705-717, Republic of Korea.
Clin Exp Metastasis. 2014 Oct;31(7):805-15. doi: 10.1007/s10585-014-9671-4. Epub 2014 Sep 25.
RhoGDP dissociation inhibitor 2 (RhoGDI2) has been identified as a regulator of tumor metastasis; however, its role in cancer remains controversial. The aims of this study were to analyze RhoGDI2 in gastric cancer growth and metastasis, and to determine its possible signaling pathway. The level of expression of RhoGDI2 was further confirmed by real time RT-RCR and Western blot analysis. Transfection of cells with RhoGDI2 shRNA resulted in no effects of cell proliferation, as determined with MTT assays. In an in vitro invasion assay, significantly fewer cells transfected with RhoGDI2 shRNA, compared with control cells, were able to invade across a Matrigel membrane barrier. The role of RhoGDI2 in the level of HGF-induced up-regulation of vascular endothelial growth factor (VEGF) was measured by knockdown of RhoGDI2 with RhoGDI2 shRNA and a chromatic immuno-precipitation assay. The levels of RhoGDI2 and VEGF were up-regulated in cells treated with HGF in a dose-dependent manner. HGF-induced up-regulation of VEGF was repressed by RhoGDI2 knockdown. HGF-induced upregulation of phosphorylated ERK and P38 levels was inhibited in RhoGDI2 knockdown cells. HGF enhanced the binding activity of RhoGDI2 to the VEGF promoter in control cells, but not in RhoGDI2-shRNA cells. Findings of this study also showed a statistically significant difference in the mean RhoGDI2 level before and after surgery (p < 0.01) and the mean level of RhoGDI2 before surgery showed a statistically significant difference depending on lymphatic, neural invasion and stage (p < 0.05). In conclusion, RhoGDI2 might play an important role in up-regulation of VEGF induced by HGF and contributes to HGF-mediated tumor invasion and metastasis, which may serve as a promising target for gastric cancer therapy.
RhoGDP解离抑制剂2（RhoGDI2）已被确定为肿瘤转移的调节因子；然而，其在癌症中的作用仍存在争议。本研究的目的是分析RhoGDI2在胃癌生长和转移中的作用，并确定其可能的信号通路。通过实时RT - RCR和蛋白质印迹分析进一步证实了RhoGDI2的表达水平。用RhoGDI2 shRNA转染细胞后，MTT法检测结果显示对细胞增殖无影响。在体外侵袭试验中，与对照细胞相比，用RhoGDI2 shRNA转染的细胞能够穿过基质胶膜屏障侵袭的细胞明显减少。通过用RhoGDI2 shRNA敲低RhoGDI2并进行染色质免疫沉淀试验，检测了RhoGDI2在肝细胞生长因子（HGF）诱导的血管内皮生长因子（VEGF）上调水平中的作用。用HGF处理的细胞中，RhoGDI2和VEGF的水平呈剂量依赖性上调。RhoGDI2敲低可抑制HGF诱导的VEGF上调。在RhoGDI2敲低的细胞中，HGF诱导的磷酸化细胞外信号调节激酶（ERK）和P38水平的上调受到抑制。在对照细胞中，HGF增强了RhoGDI2与VEGF启动子的结合活性，但在RhoGDI2 - shRNA细胞中则没有。本研究结果还显示，手术前后RhoGDI2平均水平存在统计学显著差异（p < 0.01），术前RhoGDI2平均水平根据淋巴、神经侵犯和分期存在统计学显著差异（p < 0.05）。总之，RhoGDI2可能在HGF诱导的VEGF上调中起重要作用，并有助于HGF介导的肿瘤侵袭和转移，这可能成为胃癌治疗的一个有前景的靶点。
