The ginsenoside metabolite compound K inhibits growth, migration and stemness of glioblastoma cells

Glioblastoma (GBM) is the most aggressive and malignant form of primary brain cancer. Despite recent advances in cancer treatment, it remains a substantially incurable disease. Accordingly, more effective GBM therapeutic options are urgently required. In the present study, we investigated the anticancer effect of a ginsenoside metabolite, compound K (CK), against GBM cells. CK significantly inhibited not only growth, but also metastatic ability of U87MG and U373MG cells. CK arrested cell cycle progression at the G0/G1 phase with a decrease in the expression levels of cyclin D1 and cyclin D3 in both cell types. CK also induced apoptosis in GBM cells through nuclear condensation, an increase in ROS generation, mitochondrial membrane potential depolarization, and activation of caspase-3, caspase-9 and poly(ADP-ribose) polymerase (PARP). Furthermore, CK inhibited phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway, contributing to the antiproliferative and apoptotic effects. Moreover, CK suppressed the self-renewal capacity as well as the invasiveness of U87MG and U373MG GBM stem-like cells (GSCs) by inducing a reduction in the expression of GSC markers, such as CD133, Nanog, Oct4 and Sox2. Taken together, our findings suggest that CK may potentially be useful for GBM treatment.