MiR-203 inhibits ovarian tumor metastasis by targeting BIRC5 and attenuating the TGF\u03b2 pathway

Baojin Wang,Guannan Zhao,Michelle Sims,Lawrence M Pfeffer,Huan Yan,Junming Yue,Hidemichi Watari,Yuqi Guo,Wei Li,Peixin Dong,Xia Li

doi:10.1186/s13046-018-0906-0

Abstract

BackgroundWe previously reported that miR-203 functions as a tumor suppressor in ovarian cancer cells by directly targeting transcription factor Snai2 and inhibiting epithelial to mesenchymal transition (EMT), whereas BIRC5/survivin promotes EMT. In this study, we tested our hypothesis that miR-203 inhibits ovarian tumor metastasis by suppressing EMT through targeting BIRC5, using an orthotopic ovarian cancer mouse model.MethodsWe overexpressed miR-203 in ovarian cancer SKOV3 and OVCAR3 cells using a lentiviral vector and examined cell migration and invasion using transwell plates. The small molecule inhibitor, YM155, was used to inhibit survivin expression. miR-203-expressing and control SKOV3 cells were intrabursally injected into immunocompromised NSG female mice. Primary tumors in ovaries and metastatic tumors were collected to determine the expression of survivin and EMT markers using Western blot and immunostaining.ResultsOverexpression of miR-203 inhibits EMT by targeting BIRC5 in ovarian cancer SKOV3 and OVCAR3 cells. miR-203 expression enhances the ability of the survivin inhibitor YM155 to reduce tumor cell migration and invasion in vitro. We further showed that miR-203 expression attenuated the TGFβ pathway in both SKOV3 and OVCAR3 cells. miR-203 expression also inhibited primary tumor growth in ovaries and metastatic tumors in multiple peritoneal organs including liver and spleen.ConclusionmiR-203 inhibits ovarian tumor metastasis by targeting BIRC5/survivin and attenuating the TGFβ pathway.

Highlights

We previously reported that miR-203 functions as a tumor suppressor in ovarian cancer cells by directly targeting transcription factor Snai2 and inhibiting epithelial to mesenchymal transition (EMT), whereas Baculoviral IAP Repeat Containing 5 (BIRC5)/survivin promotes EMT
We demonstrate that miR-203 expression inhibits EMT by targeting BIRC5 in ovarian cancer cells and enhances the efficacy of the survivin small molecule inhibitor YM155 on cell migration and invasion. miR-203 expression inhibits ovarian tumor metastasis by targeting BIRC5 and attenuating the TGFβ pathway in an orthotopic ovarian cancer mouse model
Cell culture Ovarian cancer cell lines SKOV3 and OVCAR3 were purchased from ATCC and maintained in Dulbecco’s Modified Eagle Medium (DMEM) supplemented with 10% FBS (Hyclone; Logan, UT), 100 U/mL penicillin, and 100 μg/mL streptomycin (Invitrogen; Carlsbad, CA). miR-203-expressing and control SKOV3 and OVCAR3 stable cell lines were established by transducing both cell lines with lentiviral vector pEF1a-miR-203 vector, and miR-203 expression was detected by polyA tailing RT-PCR as described previously [23]

Summary

Introduction

We previously reported that miR-203 functions as a tumor suppressor in ovarian cancer cells by directly targeting transcription factor Snai and inhibiting epithelial to mesenchymal transition (EMT), whereas BIRC5/survivin promotes EMT. We tested our hypothesis that miR-203 inhibits ovarian tumor metastasis by suppressing EMT through targeting BIRC5, using an orthotopic ovarian cancer mouse model. The epithelial to mesenchymal transition (EMT) is implicated in ovarian tumor metastasis. EMT is regulated by transcription factors including Snai1/2, ZEB1/2, and twist1 [11], and by multiple signaling pathways including TGFβ, AKT, ERK1/2, Notch, and WNT [12,13,14,15]. Previous studies showed that miRNAs regulate EMT in different type of cancer cells. MiR-448 inhibits EMT by directly targeting E-cadherin repressor Zeb1/2 in breast cancer cells [16]. Previous studies showed that miRNAs regulate EMT in different type of cancer cells. miR-448 inhibits EMT by directly targeting E-cadherin repressor Zeb1/2 in breast cancer cells [16].

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