1. The glycogen synthase kinase-3β/nuclear factor-kappa B pathway is involved in cinobufagin-induced apoptosis in cultured osteosarcoma cells.
- Author
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Yin JQ, Wen L, Wu LC, Gao ZH, Huang G, Wang J, Zou CY, Tan PX, Yong BC, Jia Q, and Shen JN
- Subjects
- Amphibian Venoms analysis, Amphibian Venoms chemistry, Antineoplastic Agents pharmacology, Apoptosis Regulatory Proteins genetics, Apoptosis Regulatory Proteins metabolism, Cell Cycle drug effects, Cell Line, Tumor, Cell Proliferation drug effects, Down-Regulation, Glycogen Synthase Kinase 3 genetics, Glycogen Synthase Kinase 3 beta, Humans, NF-kappa B genetics, Osteosarcoma metabolism, Phosphorylation, Poly(ADP-ribose) Polymerases genetics, Poly(ADP-ribose) Polymerases metabolism, Signal Transduction, Transcription Factor RelA genetics, Transcription Factor RelA metabolism, Transfection, Up-Regulation, Apoptosis drug effects, Bufanolides pharmacology, Glycogen Synthase Kinase 3 metabolism, NF-kappa B metabolism
- Abstract
Cinobufagin, a major component of cinobufacini (huachansu), is an important cardenolidal steroid. Several studies have suggested that cinobufagin has potent anti-cancer effects. The present study examines the apoptosis-inducing activity and the underlying mechanism of action of cinobufagin in osteosarcoma (OS) cells. Our results showed that cinobufagin potently inhibited the proliferation of U2OS, MG63 and SaOS-2 cells. Significant increases in G2/M cell-cycle arrest and apoptosis in OS cells were also observed. The expression levels of several apoptotic proteins were assessed after cinobufagin treatment in U2OS cells. Among them, xIAP, cIAP-1, survivin and Bcl-2 levels decreased remarkably, while the levels of Bax and cleaved-PARP increased. Furthermore, we validated the inhibition of GSK-3β/NF-κB signaling following cinobufagin treatment. Western blots showed a decrease in nuclear p65 protein expression after exposure to different concentrations of cinobufagin, while the phosphorylation of GSK-3β was simultaneously increased. Transduction with constitutively active forms of GSK-3β could protect against the downregulation of p65 and upregulation of cleaved-PARP that are induced by cinobufagin treatment. However, combined treatment with cinobufagin and SB216367 resulted in a significant reduction in p65 and an increase in cleaved-PARP in U2OS cells. Altogether, these results show that cinobufagin is a promising agent for the treatment of OS. These studies are the first to reveal the involvement of the GSK-3β/NF-κB pathway in cinobufagin-induced apoptosis., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2013
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