MicroRNAs in ovarian carcinomas

Abstract

The molecular mechanisms involved in epithelial ovarian cancer initiation and progression are just beginning to be elucidated. In particular, it has become evident that microRNAs (miRNAs or miRs), a class of molecules that post-transcriptionally regulate gene expression, play a major role in ovarian tumorigenesis. Several microRNA profiling studies have identified changes in microRNA patterns that take place during ovarian cancer development. While most deregulated microRNAs are down-regulated in cancer, and may therefore act as tumor suppressors, others are elevated and may represent novel oncogenes in this disease. A number of microRNAs identified as aberrantly expressed in ovarian carcinoma have been shown to have important functional roles in cancer development and may therefore represent targets for therapy. In addition, some of the microRNA patterns may have prognostic significance. The identification of functional targets represents a major hurdle in our understanding of microRNA function in ovarian carcinoma, but significant progress is being made. It is hoped that a better understanding of the microRNA expression and roles in ovarian cancer may provide new avenues for the detection, diagnosis, and therapy of this deadly disease.

Figure 1

Schematic representation of selected known targets for miRNAs that are frequently altered in ovarian carcinoma. The miRNAs frequently down-regulated in ovarian carcinoma (shown in green boxes) typically target genes that have growth promoting functions, while miRNAs that are up-regulated (red boxes) target genes that have negative effects on cell growth. These miRNAs may represent targets for therapeutic interventions.

Figure 2

MiRNAs with potential clinical use in ovarian carcinoma. List of miRNAs with potential roles in recurrence/drug resistance (Laios et al. 2008; Yang et al. 2008a; Yang, et al. 2008b), diagnosis/detection (Shell et al. 2007; Shen et al. 2008), prognosis (Nam et al. 2008a; Yang et al. 2008a; Zhang et al. 2008) of ovarian cancer. MiRNAs indicated in green are typically down-regulated in ovarian carcinoma, while miRNAs indicated in red are up-regulated.