MiR-132-3p suppresses cell proliferation and migration in gastric cancer by targeting KIF21B/Wnt/β-catenin signaling pathway

Abstract Background: Recently, kinesin family member 21B (KIF21B) has been reported to be an oncogene in non-small cell lung cancer and hepatocellular carcinoma. However, the functional role and related molecular mechanisms underlying gastric cancer (GC) pathogenesis remain largely uncovered. Methods: The expression of KIF21B was investigated by analysis of Oncomine microarray gene expression datasets and clinical specimens. The association between KIF21B and miR-132-3p was assessed by luciferase reporter assay. CCK-8 assay and transwell assay were performed to analyze the functional role of miR-132-3p/KIF21B in GC cells. Related protein expression levels were evaluated by immunohistochemistry and western blot analysis.Results: We first found that the expression of KIF21B was upregulated in GC tissues compared with adjunct normal tissues. Knockdown of KIF21B significantly suppressed the proliferation, migration and invasion in GC cell lines (AGS and SNU-5). KIF21B was confirmed as the target of miR-132-3p in GC cells. Moreover, miR-132-3p was down-regulated and inversely correlated with KIF21B expression in GC tissues. Further functional experiments demonstrated that overexpression of KIF21B remarkedly reversed the suppressive effects of miR-132-3p overexpression on GC cell proliferation, migration and invasion. Furthermore, miR-132-3p overexpression downregulated the protein levels of Wnt1, c-Myc, β-catenin, PCNA and N-cadherin, and upregulated E-cadherin expression in GC cells, which were all alleviated after KIF21B overexpression. Conclusions: In summary, our findings provide the first evidence that down-regulation of KIF21B by miR-132-3p suppresses cellular functions in GC via regulating Wnt/β-catenin signaling.