The molecular mechanism underlying ovarian cancer invasiveness and metastasis remains unclear. Since significant downregulation in microRNA 200 (miRNA200) family (miR200a, miR200b, and miR200c) has been reported in the invasive ovarian cancer cells, here, we used two human ovarian cancer cell lines, OVCAR3 and SKOV3, to study the molecular basis of miR200, matrix metalloproteinase 3 (MMP3) activation, and cancer invasiveness. We found that overexpression of either miR200 family member in OVCAR3 or SKOV3 cells significantly inhibited production and secretion of MMP3 and cancer invasiveness. Moreover, forced MMP3 expression abolished miR200-induced inhibition of ovarian cancer cell invasiveness, suggesting that miR200 family inhibited ovarian cell invasiveness via downregulating MMP3. Furthermore, ZEB1, a major target of miR200, was inhibited by miR200 overexpression. Forced ZEB1 expression abolished miR200-induced inhibition of ovarian cancer cell invasiveness, suggesting that ZEB1 is a direct target of miR200 for inhibiting ovarian cell invasiveness. Finally, phosphorylated SMAD3 (pSMAD3), a major partner of ZEB1, was efficiently inhibited by miR200, which could be restored by forced expression of ZEB1, but not by forced expression of MMP3, suggesting that ZEB1/pSMAD3 is signaling cascade upstream of MMP3 in this model. Taken together, our data suggest that miR200 family inhibited ovarian cancer cell invasiveness and metastasis by downregulating MMP3, possibly through ZEB1/pSMAD3.

Context Androgen excess is a key feature of polycystic ovary syndrome (PCOS), but the underlying molecular mechanism remains unclear. Objective To determine the role and mechanism of novel long noncoding RNA (lncRNA) highly up-regulated in PCOS (HUPCOS) in the androgen excess of PCOS patients. Design The lncRNA expression profile in granulosa cells derived from PCOS and non-PCOS women were analyzed by using microarray assay. Human granulosa cell line KGN was used for mechanism investigation. Setting This was a university-based study. Patients Thirty-eight PCOS and 38 control patients were recruited: 8 PCOS and 8 control samples used for microarray discovery, the remaining 30 PCOS cases and 30 controls for quantitative RT-PCR validation. Main Outcome Measures The aberrant expression lncRNA profile of PCOS patients was measured using microarray. The relationship of HUPCOS and follicular fluid testosterone was measured. Aromatase expression were analyzed after HUPCOS downregulation. HUPCOS interaction protein was confirmed by RNA pull-down. Results The significantly elevated lncRNA in PCOS granulosa cells was named HUPCOS, which was positively correlated with follicular fluid testosterone of PCOS patients. HUPCOS downregulation increased aromatase expression and promoted conversion of androgen to estrogen. RNA-binding protein with multiple splicing (RBPMS) was the most likely protein that combined with HUPCOS. Conclusions Our findings suggested that HUPCOS mediated androgen excess in follicular fluid of PCOS patients by suppressing aromatase expression via interaction with RBPMS.

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