MiR-10a as a Modulator of Proliferation and Cell Cycle Progression in Ovarian Clear Cell Carcinoma

Abstract

Endometriosis, a benign inflammatory disease whereby endometrial-like tissue grows outside the uterus, is a significant risk factor for endometriosis-associated ovarian cancers. In particular, ovarian endometriomas, cystic lesions of deeply invasive endometriosis, are a potential precursor lesion for ovarian clear cell carcinoma (OCCC). To explore the transcriptomic landscape, OCCC from women with pathology-proven concurrent endometriosis (n=4) were compared to benign endometriomas (n=4) by bulk RNA and small-RNA sequencing. Analysis of protein-coding genes identified 2449 upregulated and 3131 downregulated protein-coding genes (DESeq2, P<0.05, log2 fold-change>|1|) in OCCC with concurrent endometriosis compared to endometriomas. Gene set enrichment analysis showed upregulation of cell cycle regulation and DNA replication pathways and downregulation in cytokine receptor signaling and matrisome pathways. Analysis of miRNAs revealed 64 upregulated and 61 downregulated mature miRNA molecules (DESeq2, P<0.05, log2 fold-change>|1|). Hsa-miR-10a-5p represented over 21% of the miRNA molecules in OCCC with endometriosis and was significantly upregulated (NGS: log2 fold change=4.37, P=2.43E-18; QPCR: 8.1-fold change, P<0.05). Correlation between miR-10a expression level in OCCC cell lines and IC50 (50% inhibitory concentration) of carboplatin in vitro revealed a positive correlation (R2=0.92). The cellular function of miR-10a was investigated by overexpressing miR-10a in vitro. MiR-10a overexpression revealed a significant decrease in proliferation (n=6; P< 0.05), compared to a non-targeting control. Cell-cycle analysis revealed a significant shift in cells from S and G2 to G1 in (n=6; P<0.0001). MiR-10a overexpression in vitro was correlated with decreased expression of predicted miR-10a target genes critical for proliferation, cell-cycle regulation, and cell survival [SERPINE1 (3.2 downregulated; P<0.05), CDK6 (2.4 downregulated; P<0.05) and, RAP2A (2-3 downregulated; P<0.05)].