406938

MIR146A

BACKGROUND: Our previous study found that dysregulated microRNA-146a-5p (miR-146a-5p) is involved in oesophageal squamous cell cancer (ESCC) proliferation. This article aimed to evaluate its detailed mechanisms in ESCC epithelial-mesenchymal transition (EMT) progression. METHODS: Invasion assay, qRT-PCR and western blotting were used to validate the roles of miR-146a-5p and Notch2 in EMT progression. miRNA target gene prediction databases and dual-luciferase reporter assay were used to validate the target gene. RESULTS: miR-146a-5p inhibitor led to increase of invaded ESCC cells, while miR-146a-5p mimics inhibited invasion ability of ESCC cells. Protein level of E-cadherin decreased, whereas those of Snail and Vimentin increased in the anti-miR-146a-5p group, which demonstrated that miR-146a-5p inhibits EMT progression of ESCC cells. miRNA target gene prediction databases indicated the potential of Notch2 as a direct target gene of miR-146a-5p and dual-luciferase reporter assay validated it. Importantly, shRNA-Notch2 restrained EMT and partially abrogated the inhibiting effects of miR-146a-5p on EMT progression of ESCC cells. CONCLUSIONS: miR-146a-5p functions as a tumour-suppressive miRNA targeting Notch2 and inhibits the EMT progression of ESCC.

BACKGROUND/AIMS: miR-146a has recently been shown to promote cell proliferation, migration, and invasion in many cancers, but the role of miR-146a in clear cell renal cell carcinoma (ccRCC) remains unclear. METHODS: Reverse transcription quantitative PCR (RT-qPCR) was performed to investigate the mRNA expression of miR-146a and CADM2 in ccRCC tissues. The luciferase reporter assay, Western blotting, and ChIP assay were carried out to explore the promoter and the transcription factor of miR-146a. Moreover, the effect of miR-146a and CADM2 on ccRCC cells was explored using methyl thiazolyl tetrazolium, colony formation, and migration and invasion assays. The luciferase reporter assay, RT-qPCR, western blotting, and immunofluorescence assay were carried out to investigate whether CADM2 is directly regulated by miR-146a. A tumor xenograft model and immunohistochemical staining were used to examine the carcinogenic effect of miR-146a and CADM2 in vivo. RESULTS: miR-146a has been shown to promote cell proliferation, migration, and invasion. Here, we found that miR-146a is highly expressed in ccRCC tissues, whereas CADM2 is down-regulated. Hypoxia can induce the expression of miR-146a by stimulating its promoter. In addition, we demonstrated that miR-146a promoted and CADM2 inhibited proliferation, migration, and invasion of ccRCC cells. The 3' untranslated region (UTR) luciferase reporter assay identified that miR-146a targeted the 3' UTR of CADM2 and negatively regulated its expression. Ectopic expression of CADM2 counteracted the promoting effect of miR-146a on cell proliferation, migration, invasion, and the epithelial-mesenchymal transition process. CONCLUSION: Together, the finding of down-regulation of CADM2 by miR-146a can provide new insights into ccRCC pathogenesis and might contribute to the development of novel therapeutic strategies.CI - (c) 2018 The Author(s). Published by S. Karger AG, Basel.