Inhibition of in vitro and in vivo ovarian cancer cell growth by pinoresinol occurs by way of inducing autophagy, inhibition of cell invasion, loss of mitochondrial membrane potential and inhibition Ras/MEK/ERK signalling pathway.

Ovarian cancer causes considerable mortality in women across the globe. The limited availability of the efficient chemotherapeutic agents and associated side effects of the existing drugs forms a bottle neck in the treatment of ovarian cancer. In this study, the in vitro and in vivo anticancer activity of a plant derived lignan pinoresinol was investigated along with deciphering its mode of action.The anticancer activity was evaluated by MTT cell viability assay and its effects on mitochondrial membrane potential loss was checked by flow cytometry. Effects on cell invasion were measured by Matrigel invasion assay, whereas effects on autophagy were evaluated by electron microscopy and Western blotting assay. Protein expressions of the phosphor (p)-MEK and p-ERK were measured by Western blot.Results revealed that Pinoresinol inhibits the growth of the ovarian SKOV-3 cancer cells and exhibits an IC50 of 20 µM. The anticancer effects were found to be due to the induction of autophagy which was associated with increase in the expression of LC3 II and Beclin and decrease in the expression of p62. Furthermore, pinoresinol also caused reduction in the mitochondrial membrane potential (MMP) of the SKOV-3 cells and inhibited their invasion capacity. The effects of pinoresinol were also investigated on the Raf/MEK/ERK signalling pathway and it was observed that pinoresinol inhibited the expression of phosphore (p)-MEK and p-ERK in a concentration-dependent manner. Finally, in vivo evaluation revealed that pinoresinol significantly inhibited the growth of xenografted tumors in mice, indicating the potential of pinoresinol in the treatment of ovarian cancer.Pinoresinol, as per the current study, has the potential to inhibit in vitro and in vivo cancer cell growth of SKOV-3 human ovarian cancer cells and as such could be a possible drug candidate for future research.