Expression Of RhoGDI2in Colorectal Cancer And The Influence Of Its Overexpression On Biology Of This Cancer

Objective: Rho GTPase, as a significant cellular molecular switch ofcontrolling many signal transduction pathways, plays an essential role in thecytoskeleton reorganization, cell shape, cell migration, cell cycle and genetictranscription，in addition, it also plays a role in regulating tumor proliferation andapoptosis. Rho-specific guanine nucleotide dissociation inhibitor2(RhoGDI2) hasbeen identified as a regulator of Rho family GTPase and received most attention intumorigenesis and progression. RhoGDI2has been found to be vital forcarcinogenesis in bladder, breast, ovarian, pancreatic and gastric cancers, especially inregulating tumor cell apoptosis, invasion and metastasis, and angiogenesis effect,however only limited analyses have been done in the colorectal cancer. In thisresearch we aimed to further verify the expression and clinical significance ofRhoGDI2in colorectal cancer, clarify the influence of RhoGDI2on the prognosis ofpatients with colorectal cancer, research RhoGDI2in different expression incolorectal cancer cell lines, build stable expression of RhoGDI2cell lines,andevaluate the functions of RhoGDI2in colorectal cancer cells with respect togrowth,invasion, metastasis.Methods:(1) Immunohistochemistry was used to identify RhoGDI2expressionin clinical samples of colorectal cancer tissues, para-tumorous tissues and lymph nodemetastasis tissues which had different pathologic stages and integrated follow-up data.At the same time, analyzed the relationship of RhoGDI2and colorectal cancerpatients’ overall survival and disease-free survival by drawing the survival curve, andfurther defined the relevance between RhoGDI2and the prognosis of patients withcolorectal cancer.(2) The expression levels of RhoGDI2in HT29, SW620andHCT116cells was examined by qRT-PCR and Western Blot.(3) Establishedfull-length RhoGDI2expression vector and transfected the HCT116cells which hadlow expression of RhoGDI2with full-length RhoGDI2expression vector and received the stably forced expression of RhoGDI2cell lines.(4) qRT-PCR and Western Blotwere applied to identify RhoGDI2has been transfected into the cells, secured a stabletransfection cell lines concluding HCT116-RhoGDI2, HCT116-control. In HCT116cells with different expression of RhoGDI2we used CCK8and transwell chamber testto evaluate the influence of RhoGDI2on cells behaviors including proliferation,motility and invasion in vitro.Results:(1) RhoGDI2expression contributed positively with tumor progressionand metastasis in clinical tissues, the positive expression rate in primary tumor,tissueadjacent to carcinoma and lymph node was0%,33.3%,66.7%(P＜0.001). It wasassociated with the lymph node metastasis,remote metastasis (P＜0.05), but notassociated with gender, age, the size of tumor, the location of tumor, the number oftumor, the differentiation of tumor, the stage of the tumor, and the vessel and venousinvasion (P＞0.05). Patients with higher RhoGDI2expression had poorer overallsurvival and disease-free survival, while lower RhoGDI2expression had longeroverall survival and disease-free survival;(2) The RhoGDI2protein expression levelsvaried widely in colorectal cancer cells, and the expression of RhoGDI2mRNAgradually reduced in HT29, SW620, HCT116cell lines. The expression of RhoGDI2protein in HT29, SW620, HCT116was1.393805±0.1307,0.087765±0.0313,0.04362±0.017, which had statistical significance（P＜0.05）.(3) Successfullyreceived the stably forced expression of RhoGDI2cell lines. The RhoGDI2proteinexpression levels varied widely in colorectal cancer cells, and the expression ofRhoGDI2mRNA was the highest in HCT116-RhoGDI2, which had statisticalsignificance（P＜0.01）with HCT116-control and HCT116cell lines. The expressionof RhoGDI2protein in HCT116-RhoGDI2, HCT116-control and HCT116was1.5658±0.1787,0.0523±0.04396,0.0133±0.014436which had statistical significance（P＜0.01）.(4) The overexpression of RhoGDI2ehanced the colorectal cancer cellproliferation, motility, and invasion.Conclusion: Our findings forebode that RhoGDI2is up-regulation in colorectalcancer, and associated with lymph node metastasis and remote metastasis, but notassociated with gender, age, the size of tumor, the location of tumor, the number of tumor, the differentiation of tumor, the stage of the tumor, and the vessel and venousinvasion. Patients with higher RhoGDI2expression had poorer overall survival anddisease-free survival, while lower RhoGDI2expression had longer overall survivaland disease-free survival. The overexpression of RhoGDI2involved in colorectalcancer proliferation, motility and invasion. Thus RhoGDI2may be a useful marker indiagnosis and prognosis of colorectal cancer,meanwhile, a potential therapeutic targetfor better treatment.