Pterostilbene induces cell apoptosis and inhibits lipogenesis in SKOV3 ovarian cancer cells by activation of AMPK-induced inhibition of Akt/mTOR signaling cascade

This study investigates if the anti-tumor effect of Pterostilbene in the SKOV3 ovarian cancer (OC) cell line involves inhibition of cell metabolism and tested in this effect involves modulating AMPK and Akt-induced regulation of mTORC1. Initially, SKOV3 cells were cultured in the humidified conditions in DMEM media for 24 h with or without increasing concentration of Pterostilbene. Then, the cells were incubated with Pterostilbene (IC50 = 50 mu M) under similar conditions with or without pre-incubation with Dorsomorphin, an AMPK inhibitor. In a dose-dependent manner, Pterostilbene inhibited SKOV3 cell survival and increased their lysate levels of lactate dehydrogenase (LDH) and single-stranded DNA (ssDNA). When SKOV3 cells were treated with 50 mu M Pterostilbene, Pterostilbene significantly suppressed cell migration and invasion, reduced lysate levels of lactic acid and the optical density of Oil Red O staining, and increased lysate glucose levels. It also increased levels of malondialdehyde (MDA), reactive oxygen species (ROS), and induced intrinsic cell apoptosis by upregulating protein levels of Box and cleaved caspase-3 and reducing protein levels of Bcl-2. Besides, Pterostilbene reduced mRNA levels of sterol regulatory element-binding protein 1 (SREBP-1), fatty acid synthase (FAS), acetyl CoA carboxylase-1 (ACC-1), and AMP-activated protein kinase (AMPK). Furthermore, Pterostilbene increased the protein levels of p-AMPK, p-p53, p-raptor, p-TSC-2, but significantly decreased protein levels of p-Akt, p-TSC-2, p-mTOR, p-S6K1, and p-4E-BP. Treatment with Dorsomorphin (CC) abolished all the anti-tumorigenesis effects afforded by Pterostilbene and prevented Pterostilbene-induced phosphorylation of Akt, p53, and mTOR In conclusion, the tumor-suppressive effect of Pterostilbene in SKOV3 cells involves the induction of ROS and inhibition of dysregulation cell metabolism mainly due to AMPK-induced Akt-dependent or independent suppression of mTOR.