The Study On Roles Of MiR-430Target Regulated CXCR7in The Biological Behavior Of Bladder Cancer Cells And Their Corresponding Mechanisms

Objective:Bladder cancer is a common malignant tumor in human; however, the molecular mechanism underlying its growth and invasion remains unclear. MicroRNAs (miRNAs) are small, endogenous and non-coding RNAs that inhibit gene expression via interaction with target sites in the3’-untranslational region (UTRs) of mRNA.. Emerging data has shown that miRNAs play crucial roles in the regulation of various biological processes including the development of human cancers. MiRNA-430(miR-430) has mainly been researched in zebrafish, and has been shown to be associated with early embryo development. However, whether miR-430involves in the development of malignant tumors has not been reported.CXCR7is7-transmembrane chemokine receptors of the stroma-derived factor (SDF-1α). Its expression has been reported to be enhanced during tumor development, suggesting that CXCR7is an attractive therapeutic target for cancer. Yates. et al. found that CXCR7expression was elevated in bladder cancer tissues and was associated with high-grade and metastasis. Moreover, CXCR7has been demonstrated to be associated with proliferation, migration and invasion of bladder cancer through several signaling pathways including ERK, Stat3and AKT signaling. The present study firstly revealed a miR-430expression pattern in normal bladder, adjacent tissue and bladder cancer tissue. Moreover, forced overexpression of miR-430in human bladder cancer5637cells significantly inhibited cell proliferation, migration and colony-formation efficiency, entirely contrary to the results of forced overexpression of CXCR7, which was validated to be a direct target of miR-430in this study. Further analysis showed that cell proliferation-and migration-related genes including ERK, p-ERK, MMP2and MMP9were significantly downregulated in miR-430overexpressed5637cells, while markedly upregulated in CXCR7overexpressed5637cells. Our study reveals a novel role as well as a potential regulation mechanism of miR-430in bladder cancer cells. Methods:1.The expression of miR-430was detected by Real-time PCR in thebladder cancer, adjacent tissues and normal tissues.The regulatory relation between miR-430and CXCR7was tested and verified by the Dual-Luciferase reporter assays.2. Construct the vectors of miR-430and CXCR7overexpression3. Effects of miR-430and CXCR7overexpression on proliferation,cell cycle, colony-formation efficiency and migration of5637cells were detected by MTT assays, flow cytometry assays and Trans-Well.4. The expressions of ERK、p-ERK、MMP-2and MMP-9in cellswhich were transfected with miR-430lentiviral vectors and CXCR7over-expression vectors were detected, to seek the signal control paths of their regulatory relation.Results:1.The bladder cancer tissues showed lower expression of miR-430th an normal tissue and adjacent tissues. Moreover, the higher stage of blad der cancer, the lower expression of miR-430. Dual Luciferase reporter assays Show that CXCR7was the direct target of miR-430.and miR-430can induce the expression of CXCR7.2. The vectors of miR-430and CXCR7overexpression were constructed.3. forced overexpression of miR-430in human bladder cancer5637cells significantly inhibited cell proliferation, migration and colony-formation efficiency, entirely contrary to the results of forced overexpression of CXCR7, which was validated to be a direct target of miR-430in this study.4.The results indicated that the expressions of ERK,p-ERK, MMP-2and MMP-9was decreased in cells transfected with miR-430lentiviral v ectors, while increased in the cells transfected with CXCR7overexpression vectors when compared with controls.