TPX2 in malignantly transformed human bronchial epithelial cells by anti-benzo[ a ]pyrene-7,8-diol-9,10-epoxide

• Published in: Toxicology (Amsterdam) 2008-10, Vol.252 (1), p.49-55
• Main Authors: Zhang, Lijuan, Huang, He, Deng, Luyao, Chu, Ming, Xu, Lan, Fu, Juanling, Zhu, Yunlan, Zhang, Xiuchun, Liu, Shulin, Zhou, Zongcan, Wang, Yuedan
• Format: Article
• Language: English
• Subjects: 7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide - toxicity; Anti-benzo[ a]pyrene-7,8-diol-9,10-epoxide; Apoptosis - drug effects; Biological and medical sciences; Blotting, Western; Bronchi - cytology; Bronchi - drug effects; Cell Cycle - drug effects; Cell Cycle Proteins - genetics; Cell Cycle Proteins - metabolism; Cell Line, Tumor; Cell Proliferation - drug effects; Cell Transformation, Neoplastic - genetics; Cell Transformation, Neoplastic - metabolism; Databases, Protein; Electrophoresis, Gel, Two-Dimensional; Emergency; Epithelial Cells - drug effects; Gene Expression - drug effects; Humans; Immunohistochemistry; Immunoprecipitation; Isoelectric Focusing; Lung cancer; Medical sciences; Microtubule-Associated Proteins - genetics; Microtubule-Associated Proteins - metabolism; Mutagens - toxicity; Nuclear Proteins - genetics; Nuclear Proteins - metabolism; Phosphorylation - drug effects; Pneumology; RNA Interference; RNA, Small Interfering; Sister Chromatid Exchange - drug effects; Toxicology; TPX2; Tumors of the respiratory system and mediastinum; Tyrosine - metabolism; Tyrosine phosphorylation; Xenopus
• ISSN: 0300-483X; 1879-3185
• DOI: 10.1016/j.tox.2008.07.059

Abstract In order to elucidate the function of the targeting protein for Xenopus kinesin-like protein 2 (Xklp2) (TPX2) in the malignant transformation of human bronchial epithelial cells induced by anti-benzo[ a ]pyrene- trans -7, 8-dihydrodiol-9, 10-epoxide (anti-BPDE), TPX2 was characterized in cells at both the gene and the protein levels. TPX2 was present at higher levels in 16HBE-C cells than in 16HBE cells as demonstrated by two-dimensional gel electrophoresis, immunocytochemistry, Western blot analysis and RT-PCR. TPX2 was also detected in lung squamous-cell carcinoma tissues by immunohistochemistry, but not in normal lung tissues. Depression of TPX2 by RNA interference in 16HBE-C cells led to a decrease in cell proliferation, S-phase cell cycle arrest and cell apoptosis. Abnormal TPX2 tyrosine phosphorylation was detected in 16HBE-C cells, and this could be inhibited, to different degrees, by tyrosine kinase inhibitors. Inhibiting tyrosine phosphorylation in 16HBE-C cells by three selected tyrosine protein kinase inhibitors, tyrphostin 47, AG112 and AG555, caused G0 /G1 -phase cell cycle arrest. Our results suggest that anti-BPDE can cause the over-expression of TPX2 and its aberrant tyrosine phosphorylation. Misregulation of TPX2 affects the cell cycle state, proliferation rates and apoptosis.