MicroRNA activity profile in the ovarian cancer cell line OVCAR3 identifies a proapoptotic effect of miR-23a

Abstract

Introduction: Molecular profiling has revealed that many microRNAs (miRNAs) are highly expressed in ovarian carcinoma. However, it is not yet known which miRNAs are biologically active (ie, they suppress expression of a target gene) in ovarian cancer cells. Here we set out to determine the most active miRNAs in ovarian cancer cells. Methods: We performed miRNA molecular profiling by quantitative polymerase chain reaction array, and measured miRNA activity using a library of sensor vectors for 291 different conserved miRNAs. We inhibited miR-23a activity using a lentiviral-based decoy, and measured the percentage of apoptotic cells by flow cytometry. Results: Our miRNA activity profiling identified 54 active miRNAs in OVCAR3 cells, and found that over 150 miRNAs had no detectable activity. To study the function of an active miRNA, we selected miR-23a for further analysis. We inhibited miR-23a in OVCAR3 cells using a decoy vector, and found that there was decreased cell death compared to control (7.4%±1.4% versus 11.2%±0.5%; P<0.05) when the cells were treated with cisplatin. Moreover, the percentage of apoptotic cells was significantly lower in miR-23a inhibited cells compared to control (2.3%±0.4% versus 9.4%±2.6%; P<0.05). Conclusion: This study identifies the active miRNAs in OVCAR3 cells, and suggests that miR-23a may help to regulate chemosensitivity of ovarian cancer cells.