Triptolide induces growth inhibition and apoptosis of human laryngocarcinoma cells by enhancing p53 activities and suppressing E6-mediated p53 degradation.
Triptolide, an active compound extracted from Chinese herb Leigongteng (Tripterygium wilfordii Hook F.), shows a broad-spectrum of anticancer activity through its cytotoxicity. However, the efficacy of triptolide on laryngocarcinoma rarely been evaluated, and the mechanism by which triptolide-induced cellular apoptosis is still not well understood. In this study, we found that triptolide significantly inhibited the laryngocarcinoma HEp-2 cells proliferation, migration and survivability. Triptolide induces HEp-2 cell cycle arrest at the G1 phase and apoptosis through intrinsic and extrinsic pathways since both caspase-8 and -9 are activated. Moreover, triptolide enhances p53 expression by increasing its stability via down-regulation of E6 and E6AP. Increased p53 transactivates down-stream target genes to initiate apoptosis. In addition, we found that short time treatment with triptolide induced DNA damage, which was consistent with the increase in p53. Furthermore, the cytotoxicity of triptolide is decreased by p53 knockdown or use of caspases inhibitor. In conclusion, our results demonstrated that triptolide inhibits cell proliferation and induces apoptosis in laryngocarcinoma cells by enhancing p53 expression and activating p53 functions through induction of DNA damage and suppression of E6 mediated p53 degradation. These studies indicate that triptolide is a potential anti-laryngocarcinoma drug.
Key Laboratory of Agricultural Molecular Biology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi Province, People's Republic of China.
Fei
F
Zhao
Weiwei
W
Huang
Tamgue
T
Ousman
Bin
B
Zhang
Yangyang
Y
Han
Daguia Zambe John
DZ
Clotaire
Chen
C
Wang
Huanhuan
H
Chang
Huanan
H
Luo
Xiaoyong
X
Ren
Ming
M
Lei
D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D004224:Diterpenes / Q000494:pharmacology*; D004852:Epoxy Compounds / Q000494:pharmacology; D006801:Humans; D007822:Laryngeal Neoplasms / Q000378:metabolism*; D009856:Oncogene Proteins, Viral / Q000378:metabolism*; D010616:Phenanthrenes / Q000494:pharmacology*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
D000970:Antineoplastic Agents; D004224:Diterpenes; D004852:Epoxy Compounds; D009856:Oncogene Proteins, Viral; D010616:Phenanthrenes; D016159:Tumor Suppressor Protein p53; C001899:triptolide