The Role Of MiR-22and MiR-200b On Gastric Cancer Biological Behaviour And The Molecular Mechanism

Purpose: In this study we investigated the potential effects of miR-22and miR-200bon gastric cancer biological behaviour and the molecular mechanism.Methods: The expression of miR-22and miR-200b in89cases of gastric cancerpatients’ tissues and41cases of normal stomach mucosa were examined by In situhybridization (ISH) analysis; A luciferase assay was conducted for targetidentification; qRT-PCR and Western blot analysis was performed to detect the proteinand mRNA expression of Wnt-1regulated by miR-22and miR-200b in MGC-803cells; RNA interference was imployed to silence Wnt-1in MGC-803cells; Theability of proliferation, migration, invasion and apoptosis of gastric cancer cellsregulated by miR-22, miR-200b and si-Wnt-1in vitro were evaluated by MTT,wound-healing, transwell invasion assays and Annexin V/propidium iodide staining.Results: In situ hybridization showed that miR-22and miR-200b were downregulatedin gastric cancer tissues, and the expression levels of both them were positivelycorrelated in gastric cancer tissues. The expression of miR-22and miR-200b werenegatively correlated with the clinical stage and lymph node metastasis in gastriccancer patients; Luciferase reporter vector system confirmed that Wnt-1was the targetgene of both miR-22and miR-200b. qRT-PCR and Western blot analysis resultsshowed that a notable reduction of the mRNA and protein level of Wnt-1by restoredof miR-22or miR-200b; MTT assay showed that ectopic expression of miR-22andmiR-200b or si-Wnt-1could significantly inhibite MGC-803cell proliferationcapacity compared with the control group, however, miR-200b or miR-22inhibitorscould antagonize the role of si-Wnt-1; wound-healing assay showed that ectopicexpression of miR-22and miR-200b or si-Wnt-1could significantly inhibiteMGC-803cell migration capacity compared with the control group, nevertheless,miR-200b or miR-22inhibitors could antagonize the role of si-Wnt-1; transwellinvasion assays showed that ectopic expression of miR-22and miR-200b or si-Wnt-1 could significantly inhibite MGC-803cell invasion capacity compared with thecontrol group, whereas, miR-200b or miR-22inhibitors could antagonize the role ofsi-Wnt-1; Annexin V/propidium iodide staining showed that ectopic expression ofmiR-22and miR-200b or si-Wnt-1could significantly induce MGC-803cellapoptosis compared with the control group, however, miR-200b or miR-22inhibitorscould antagonize the role of si-Wnt-1.Conclusions:1. The expression level of miR-22and miR-200b was downregulated in gastriccancer and had a close correlation to lymph node metastasis and advanced clinicalstage.2. Wnt-1is the target gene of both miR-22and miR-200b.3. miR-22and miR-200b inhibited gastric cancer cell proliferation, migration,invasion and induce apoptosis by targeting Wnt-1.