Purpose: Ovarian cancer (OC) is perhaps the most difficult problem in gynaecologic oncology; in particular the drug-resistant ovarian cancer remains a challenge for the clinicians. Therefore there is a pressing need for novel and effective chemotherapeutic agents against OC. The main objective of the current research work was to study the anticancer effects of a naturally occurring triterpene acid, ursolic acid, against SKOV-3 OC cells. Its effects on reactive oxygen species (ROS)-mediated apoptosis were also studied along with cell cycle phase distribution and PI3K/AKT signalling pathway.
Methods: Cell proliferation was checked by CCK8 cell viability assay. Apoptosis-related studies were examined by fluorescent microscopy using acridine orange (AO)/ethidium bromide (EB) and DAPI staining as well as flow cytometry using annexin V/propidium iodide (PI) assay. Further, western blot assay was used to study effects of ursolic acid on the apoptosis-related protein expressions including Bax, Bcl-2 as well as PI3K/AKT signalling pathway. Effects on cell cycle were examined by flow cytometry while effects on ROS production were evaluated by fluorescent microscopy.
Results: Ursolic acid caused significant reduction in the viability of the SKOV-3 ovarian carcinoma cells in a dose-dependent manner, exhibiting an IC50 of 35 µM in cancer cells and IC50 of 75 µM in normal cell lines (normal ovarian surface epithelial (OSE). Ursolic acid inhibited the viability of cancer cells via induction of apoptotic cell death which was associated with increase in Bax and decrease in Bcl-2 levels. DAPI staining results also confirmed that ursolic acid induced apoptotic cell death. Ursolic acid also induced dose-dependent G2/M phase cell cycle arrest along with causing significant upsurge in ROS production. Western blot analysis revealed that ursolic acid had the potential to inhibit I3K/AKT signalling pathway.
Conclusion: The results of this study clearly indicate that ursolic acid has the potential to be developed as a potent drug candidate against OC provided further in vivo and toxicological studies are carried out.