Combination of miRNA-379-5p and miRNA-125a-3p for the treatment of platinum resistant ovarian cancer

Ovarian cancer (OC) is the second most common gynecologic cancer and the leading cause of death from cancers of the female reproductive system. The development of resistance to first-line platinum chemotherapy (e.g., cisplatin, carboplatin) contributes to high recurrence and lethality of OC, with over 50% of patients with advanced-stage OC relapsing due to drug resistance within two years of remission. Therefore, there is a need for alternative methods to treat platinum-resistant OC (PROC). Among several mechanisms, resistance to platinum-based therapy has been linked to upregulation of focal adhesion kinase (FAK), which activates signaling pathways that promote cell migration, invasion, adhesion, proliferation, and survival, and its overexpression is an accurate predictor of poor survival. Because FAK inhibitors have been unsuccessful when tested as single agents, combining them with other therapeutic agents may be more effective. Combination therapies are promising as they can improve treatment response while minimizing resistance and adverse side effects. Furthermore, cancer is often driven by multiple molecular pathways, and thus, a single therapy may not be sufficient. miRNA-379-5p has been shown to act as a tumor suppressor by directly targeting FAK and is downregulated in several OC cell lines and patient tumor samples. Additionally, overexpression of miRNA-125a-3p has been shown to inhibit cell invasion, migration, and proliferation, and induce apoptosis and cell cycle arrest in OC cells. BCL2-related ovarian killer (BOK) is a direct downstream target of miRNA-125a-3p, which acts as a pro-apoptotic regulator, and its protein levels can be increased by miRNA-125a-3p. The objective of this study was to investigate the dual delivery of miRNA-379-5p and miRNA-125a-3p for the treatment of PROC. OVCAR3 cells (i.e., adenocarcinoma ovarian cells shown to be platinum resistant) were transfected with each miRNA individually or in combination using Lipofectamine RNAiMAX, and cell viability was assessed using an MTT assay after 48 and 72 hours. After 48 hours, miRNA-379-5p, miRNA-125a-3p, and a combination of these miRNAs reduced cell viability by ~5, 14, and 21%, respectively, compared to the negative control. After 72 hours of exposure, both individual miRNA treatments significantly reduced cell viability by ~13%, while the treatment with both miRNAs reduced cell viability by ~28% compared to the negative control. The treatment of OVCAR3 with the combination of miRNA-379-5p and miRNA-125a-3p was able to significantly reduce cell viability compared to the treatment with each miRNA alone, suggesting a possible additive effect on cell death. Future studies will evaluate the mechanisms underlying reduced cell viability by investigating protein levels of markers for apoptosis, proliferation, and invasion.