Probucol suppresses human glioma cell proliferation in vitro via ROS production and LKB1-AMPK activation

• Published in: Acta pharmacologica Sinica Vol. 35; no. 12; pp. 1556 - 1565
• Main Authors: Jiang, Yong-sheng, Lei, Jing-an, Feng, Fang, Liang, Qi-ming, Wang, Fu-rong
• Format: Journal Article
• Language: English
• Published: United States Nature Publishing Group 01.12.2014
• Subjects: 26S蛋白酶体; AMP-Activated Protein Kinases - antagonists & inhibitors; AMP-Activated Protein Kinases - genetics; AMP-Activated Protein Kinases - metabolism; Antineoplastic Agents - pharmacology; Antioxidants - pharmacology; Cell Line, Tumor; Cell Proliferation - drug effects; Cyclin-Dependent Kinase Inhibitor p27 - metabolism; Dose-Response Relationship, Drug; Enzyme Activation; Glioma - enzymology; Glioma - genetics; Glioma - pathology; Humans; Original; Oxidative Stress - drug effects; Phosphorylation; Probucol - pharmacology; Proteasome Endopeptidase Complex - metabolism; Proteasome Inhibitors - pharmacology; Protein Kinase Inhibitors - pharmacology; Protein-Serine-Threonine Kinases - genetics; Protein-Serine-Threonine Kinases - metabolism; Reactive Oxygen Species - metabolism; RNA Interference; ROS; Signal Transduction - drug effects; Transfection; 体外培养; 普罗布考; 活化; 生产; 细胞增殖; 脑胶质瘤
• ISSN: 1671-4083; 1745-7254
• DOI: 10.1038/aps.2014.88

Aim： Probucol, an anti-hyperlipidemic drug, has been reported to exert antitumor activities at various stages of tumor initiation, promotion and progression. In this study we examined whether the drug affected glioma cell growth in vitro and the underlying mechanisms. Methods： Human glioma U87 and glioblastoma SF295 cell lines were used. Cell proliferation was accessed using the cell proliferation assay and BrdU incorporation. The phosphorylation of AMPK, liver kinase B1 （LKB1） and p27Kip1 was detected by Western blot. The activity of 26S proteasome was assessed with an in situ fluorescent substrate, siRNAs were used to suppress the expression of the rel- evant signaling proteins. Results： Treatment of U87 glioma cells with probucol （10-100 pmol/L） suppressed the cell proliferation in dose- and time-dependent manners. Meanwhile, probucol markedly increased the ROS production, phosphorylation of AMPK at Thr172 and LKB1 at Ser428 in the cells. Furthermore, probucol significantly decreased 26S proteasome activity and increased p27Kip1 protein level in the cells in an AMPK-dependent manner. Probucol-induced suppression of U87 cell proliferation could be reversed by pretreatment with tempol （a superoxide dismutase mimetic）, MG132 （proteasome inhibitor） or compound C （AMPK inhibitor）, or by gene silencing of LKB1, AMPK or p27Kip1. Similar results were observed in probucoi-treated SF295 cells. Conclusion： Probucol suppresses human glioma cell proliferation in vitro via ROS production and LKB1-AMPK activation, which reduces 26S proteasome-dependent degradation of p27Kip1.