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Dig Dis Sci. 2014 Aug;59(8):1743-53. doi: 10.1007/s10620-014-3087-5. Epub 2014 Mar 13.

miR-638 suppresses cell proliferation in gastric cancer by targeting Sp2.

Author information

1
Department of Genetics and Cell Biology, Environment and Genes Related to Diseases Key Laboratory of Education Ministry, College of Medicine, Xi'an Jiaotong University, Xi'an, 710061, People's Republic of China, lingyuzhao@aliyun.com.

Abstract

BACKGROUND:

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.

AIMS:

The purpose of this study was to determine the role of miR-638 and to elucidate its regulatory mechanism in GC.

METHODS:

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.

RESULTS:

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.

CONCLUSIONS:

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.

PMID:
24623314
DOI:
10.1007/s10620-014-3087-5
[Indexed for MEDLINE]

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