MicroRNA-212 functions as an epigenetic-silenced tumor suppressor involving in tumor metastasis and invasion of gastric cancer through down-regulating PXN expression
Authors: Yi Liu
Heping Chen
Binbin Gong
Daojiang Li
Chao Cao
Hong Xiong
Jianbo Xiong
Miantian Yang
Lingyu Qiu
Xiongwen Yang
Yi Cao
Hongping Chen
Guoyang Zhang
Zhengrong Li
Shuping Jiang
Yufeng Yan
Zhigang Jie
Journal: American journal of cancer research (2015)
Discipline: CLINICAL MEDICINE
Keywords: 5-aza-2’-deoxycytidine; MiR-212; PXN; cancer invasion; cancer metastasis
Affiliations: Department of Gastrointestinal Surgery, First Affiliated Hospital, Nanchang University Nanchang 330000, Jiangxi Province, China ; Nanchang University Medical College Nanchang 330000, Jiangxi Province, China., Department of Gastrointestinal Surgery, First Affiliated Hospital, Nanchang University Nanchang 330000, Jiangxi Province, China., Nanchang University Medical College Nanchang 330000, Jiangxi Province, China., The Key Laboratory of Basic Pharmacology, School of Pharmaceutical Science, Nanchang University Nanchang 330006, Jiangxi Province, China., Department of Histology and Embryology, Medical College, Nanchang University Bayi Road 603, Nanchang 330006, China.

Abstract:  Altered expression of paxillin (PXN) is closely linked to the pathogenesis progression, metastasis and prognosis of different malignancies including gastric cancer (GC). Epigenetic silencing of tumor-suppressive microRNAs (miRNAs) is a crucial component of the mechanism underlying activation of oncogenes in tumor. To screen for epigenetically silenced miRNAs which target PXN in GC, we performed bioinformatics algorithms and real-time PCR analysis, and identified miR-212 as the optimum candidate gene. A luciferase reporter gene assay validated that miR-212 directly targets the 3'UTR region of PXN. Importantly, miR-212 levels were inversely correlated with PXN expression in GC cell lines and clinical tumor tissues. The use of miR-212 minics decrease PXN mRNA and protein level in GC cell lines. Moreover, low expression of miR-212 and its promoter hypermethylation were causally related and were associated with aggressive tumor phenotype and adverse prognosis in GC. Restoring mir-212 expression by exogenous mirprecursor molecules transfection or reexpression of endogenous miR-212 treated by 5-aza-2'-deoxycytidine (5-aza) can exert similar effect that reduce GC cells invasion and metastasis abilities in vitro by interacting PXN gene. In addition, 5-aza-induced PXN reduction could be partically blocked by miR-212 inhibitor, resulting in a reversal of weankening cell migration and invasion ability of 5-aza. A rescue experiment and a loss-of-function experiment in vitro and vivo showed that PXN restoration rescues migration and invasion phenotype in miR-212 overexpressed GC cell lines and PXN knockdown blocks GC cells migration and invasion in the presence miR-212 inhibitors. Taken together, our results clearly show that overexpression of PXN induced by methylationsuppressed miR-212 promotes tumor metastasis and invasion, and regulation of miR-212 expression may be a novel therapeutic strategy for gastric cancer. 

Retracted: No

PubPeer comments:
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