Protein arginine methyltransferase 5 (PRMT5) is implicated in various types of human cancer and tumor development, especially in lung cancer. Nevertheless, it is still unclear whether suppression of PRMT5 could promote lung cancer cell apoptosis and chemosensitivity induced by resveratrol, and the underlying molecular mechanism remains completely unknown. Here, we showed that PRMT5 was overexpressed in human lung cancer tissues and different types of lung cancer cell lines. Moreover, we constructed PRMT5 stable knockdown cell lines (A549 and ASCT-a-1) and investigated the roles of PRMT5 and the related signaling pathway in lung cancer cell apoptosis induced by resveratrol. Our results indicated that inhibition or down-regulation of PRMT5 by GSK591, a PRMT5-specific inhibitor, or shRNAs markedly enhanced cell apoptosis and chemosensitivity stimulated by resveratrol. Further investigation showed that inhibition or down-regulation of PRMT5 further reduced Akt/GSK3β phosphorylation and the downstream targets cyclin D1 and E1 expression upon resveratrol treatment. Our findings suggest that PRMT5 is a pivotal mediator for human lung cancer cell death induced by resveratrol, which also reveals that PRMT5 may serve as a new therapeutic target for the treatment of human lung cancer.
Keywords: Akt; GSK3β; PRMT5; cyclin D1; cyclin E1; lung cancer; resveratrol.