miR-638 Suppresses Cell Proliferation in Gastric Cancer by Targeting Sp2
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MicroRNAs play important roles in the development and progression of various cancers. Recent studies have shown that miR-638 was downregulated in several tumors; however, its role in gastric cancer (GC) has not been investigated in detail.
The purpose of this study was to determine the role of miR-638 and to elucidate its regulatory mechanism in GC.
The expression levels of miR-638 and specificity protein 2 (Sp2) were detected by real-time PCR and Western blotting in GC. After pcDNA6.2-GW/EmGFP-miR-638 vector, miR-638 inhibitor and Sp2-siRNA transfection, the AGS cell proliferation was investigated by MTT assay and cell cycle, and apoptosis was detected using the Annexin V/PI. In addition, the regulation of Sp2 by miR-638 was evaluated by real-time RT-PCR, Western blot and luciferase reporter assays; cyclin D1 expression was measured by Western blotting.
The expression of miR-638 is dramatically down-regulated and Sp2 expression is remarkably up-regulated in GC tissues. Luciferase assays revealed that miR-638 inhibited Sp2 expression by targeting the 3′-UTR of Sp2 mRNA. Overexpression of miR-638 and Sp2-siRNA reduced Sp2 expression at both the mRNA and protein levels in vitro, and inhibition of miR-638 increased Sp2 expression. Moreover, we found that miR-638 overexpression and Sp2-siRNA markedly suppressed cell proliferation with decreasing expression of cyclin D1 and inducing G1-phase cell-cycle arrest in vitro; inhibition of miR-638 significantly promoted cell proliferation by increasing expression of cyclin D1 and leading more cells into the S and G2/M phase.
Our results demonstrated that miR-638 suppressed GC cell proliferation by targeting Sp2 with influence on the expression of cyclin D1. We suggest that miR-638 might be a candidate predictor or an anticancer therapeutic target for GC patients.
KeywordsmiR-638 Gastric cancer Sp2 Proliferation
This work was supported by a grant from China Postdoctoral Science Foundation grant (No. 2013M542358) and a fund from the Fundamental Research Funds for the Central Universities, China.
Conflict of interest
- 11.Zhang F, Yang Z, Cao M, et al. MiR-203 suppresses tumor growth and invasion and down-regulates MiR-21 expression through repressing Ran in esophageal cancer. Cancer Lett. 2014;342:121–129.Google Scholar
- 14.Gopalan V, Pillai S, Ebrahimi F, et al. Regulation of microRNA-1288 in colorectal cancer : Altered expression and its clinicopathological significance. Mol Carcinog. 2013;53:E36–E44.Google Scholar