Circ_0070203 Promotes Epithelial-mesenchymal Transition in Ovarian Serous Cystadenocarcinoma through miR-370-3p/TGFßR2 Axis.

ABSTRACT

INTRODUCTION: Circular RNAs (circRNAs) are important biological molecules associated with the pathogenesis of multiple cancers. OBJECTIVE: This work aimed to investigate the function and molecular mechanism of circ_0070203 in high-grade serous ovarian cystadenocarcinoma (HGSOC). METHODS: circRNA microarray was conducted to detect the circ_0070203 expression in HGSOC tissues. Bioinformatics analysis was used to find the binding sites between circ_0070203, miR- 370-3p and TGFßR2. Real-time quantitative reverse transcription PCR (RT-qPCR) was executed to detect the expressions of circ_0070203, miR-370-3p and TGFßR2 in HGSOC tissues and SKOV3 cells. Dual-luciferase reporter gene assay was used to validate the relationships between miR-370-3p and circ_0070203 or TGFßR2. Besides, transwell assays were conducted to assess the migrative, invasive abilities of ovarian cancer (OC) cells. Western blotting was adopted to detect the expression of epithelial-mesenchymal transition (EMT)-related proteins. The related patents were also studied during the research. RESULTS: Circ_0070203 and TGFßR2 were upregulated, while miR-370-3p was downregulated in FIGO stage III-IV HGSOC tissues and SKOV-3 cell lines. circ_0070203 overexpression changed the expression of other EMT-related proteins and enhanced the migrative, invasive abilities of OC cells, while silencing circ_0070203 worked oppositely. Mechanistically, circ_0070203 could upregulate TGFßR2 expression in OC cells via sponging miR-370-3p. CONCLUSION: Circ_0070203 could promote the epithelial-mesenchymal transition, invasion, and metastasis of HGSOC via regulating the miR-370-3p/TGFßR2 axis. Our findings provided a potential biomarker for HGSOC therapy.