MicroRNAs in ovarian cancer biology and therapy resistance

Since 2006, an increasing number of studies have indicated an essential role for microRNAs in ovarian cancer tumorigenesis. In this review, we provide an overview of the microRNAs that have been associated with different aspects of ovarian cancer, such as tumor subtype, stage, histological grade, germline mutations in BRCA genes, prognosis and therapy resistance. We highlight the role of the let-7 and miR-200 families, two major microRNA families that are frequently dysregulated in ovarian cancer and have been associated with poor prognosis. Interestingly, both have been implicated in the regulation of the epithelial-to-mesenchymal transition, a cellular transition associated with tumor aggressiveness, tumor invasion and chemoresistance. Furthermore, we discuss several other microRNAs that have been associated with chemotherapy resistance, such as miR-214, miR-130a, miR-27a and miR-451. In the final section, we speculate on the possibilities of microRNA-based therapies and the use of microRNAs as diagnostic tools.