Mechanism Of Action Of MiR-339-5p Targeting Tspan15 To Inhibit Invasive Migration Of Breast Cancer Cells

Objectives:Breast cancer is the most common tumor among women worldwide and the leading cause of death among women with cancer,with approximately 1.67 million cases of breast cancer diagnosed each year.Breast cancer metastasis is an important reason in the failure of breast cancer treatment.Tspan15,a member of the four-transmembrane protein family,functions as a transmembrane transporter protein,and our group found that Tspan15 is highly expressed in breast cancer tissues and may be a potential breast cancer-related gene,but the mechanism of Tspan15 protein’s role in breast cancer invasion and metastasis is still unclear.miR-339-5p can inhibit tumor invasion and metastasis,but its role involves However,its role involves different target genes and many mechanisms are still unclear and need to be further investigated.In the present study,we investigated the role of Tspan15 in MCF-7 and MDA-MB-231 cell lines,and further explored the targeting and regulatory effects of upstream miRNAs on it,and initially explored its mechanism of action.Methods:1.analyze the expression of Tspan15 m RNA in breast cancer in TCGA database using bioinformatics website;K-M plotter database to analyze whether there is a correlation between Tspan15 expression and patient survival.2.analyze the effects of Tspan15 silencing mediated by si RNA on MCF-7,MDA-MB-231 two breast cancer cell Biological properties:(1)CCK-8assay,Transwell,and scratch assay were performed to analyze the effect of Tspan15 silencing on the proliferation,invasion and migration ability of breast cancer cells,respectively.(2)RT-q PCR and Western Blot to detect the effects of silencing Tspan15 on the expression levels of N-cadherin,β-catenin,and MMP-2 in breast cancer cells MCF-7 and MDA-MB-231 cells.3.Targetscan was used to analyze the targeting regulation of miR-339-5p on Tspan15 The effect was verified by dual luciferase reporter assay.4.RT-q PCR and Western Blot assays were used to detect the effect of miR-339-5p expression on Tspan15 expression.5.miR-339-5p mimics assays were used to detect its effect on the biological properties of breast cancer cells.All experiments were repeated three times,and the results were statistically analyzed using SPSS23.0 statistical software,and the differences were considered statistically significant at P<0.05.Results:1.Clinical validation and raw letter analysis showed that Tspan15 was highly expressed in breast cancer tissues.2.Silencing Tspan15 inhibited invasive migration of breast cancer cells by downregulating the expression of EMT-related factors N-cadherin,β-catenin,and MMP-2.3.Dual luciferase validation of miR-339-5p could target Tspan15.4.The mimics of miR-339-5p mimics can inhibit breast cancer cell proliferation and miR-339-5p inhibitorinhibitor promotes the proliferation ability of breast cancer cells;the mimics of miR-339-5p mimics inhibit the invasion and migration ability of breast cancer cells;the mimics of miR-339-5p mimics can increase the proliferation ability of MCF-7 and MDA-MB-231 cells;overexpression of miR-339-5p can block the cell cycle of MCF-7 cells.Conclusions:1.Tspan15 was highly expressed in breast cancer tissues from clinically collected specimens and TCGA database,and correlated with patients’ DFS,and the expression level correlated significantly with prognosis.2.Tspan15 could promote invasive migration of breast cancer cells through upregulation of EMT-related factors N-cadherin,β-catenin,and MMP-2,and the specific mechanism needs to be further investigated.3.miR-339-5p can target Tspan15 in breast cancer cell lines,and may also inhibit breast cancer cell invasion and migration by targeting other genes,the mechanism of which needs to be further investigated.