Dehydrocostuslactone Suppresses Angiogenesis In Vitro and In Vivo through Inhibition of Akt/GSK-3 beta and mTOR Signaling Pathways

作者:Wang Chih Ya*; Tsai An Chi; Peng Chieh Yu; Chang Ya Ling; Lee Kuo Hsiung; Teng Che Ming; Pan Shiow Lin
来源:PLos One, 2012, 7(2): e31195.
DOI:10.1371/journal.pone.0031195

摘要

The traditional Chinese medicine component dehydrocostuslactone (DHC) isolated from Saussurea costus (Falc.) Lipschitz, has been shown to have anti-cancer activity. Angiogenesis is an essential process in the growth and progression of cancer. In this study, we demonstrated, for the first time, the anti-angiogenic mechanism of action of DHC to be via the induction of cell cycle progression at the G0/G1 phase due to abrogation of the Akt/glycogen synthase kinase-3 beta (GSK-3 beta)/cyclin D1 and mTOR signaling pathway. First, we demonstrated that DHC has an anti-angiogenic effect in the matrigel-plug nude mice model and an inhibitory effect on human umbilical vein endothelial cell (HUVEC) proliferation and capillary-like tube formation in vitro. DHC caused G0/G1 cell cycle arrest, which was associated with the down-regulation of cyclin D1 expression, leading to the suppression of retinoblastoma protein phosphorylation and subsequent inhibition of cyclin A and cdk2 expression. With respect to the molecular mechanisms underlying the DHC-induced cyclin D1 down-regulation, this study demonstrated that DHC significantly inhibits Akt expression, resulting in the suppression of GSK-3b phosphorylation and mTOR expression. These effects are capable of regulating cyclin D1 degradation, but they were significantly reversed by constitutively active myristoylated (myr)-Akt. Furthermore, the abrogation of tube formation induced by DHC was also reversed by overexpression of Akt. And the co-treatment with LiCl and DHC significantly reversed the growth inhibition induced by DHC. Taken together, our study has identified Akt/GSK-3 beta and mTOR as important targets of DHC and has thus highlighted its potential application in angiogenesis-related diseases, such as cancer.