This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Cheung, H. W. Articles by Wang, X. Search for Related Content PubMed PubMed Citation Articles by Cheung, H. W. Articles by Wang, X.

Mitotic Arrest Deficient 2 Expression Induces Chemosensitization to a DNA-Damaging Agent, Cisplatin, in Nasopharyngeal Carcinoma Cells

Departments of ¹ Anatomy and ² Biochemistry, Faculty of Medicine, University of Hong Kong, Hong Kong, China

Requests for reprints: Xianghong Wang, Department of Anatomy, University of Hong Kong, 1/F, Faculty of Medicine Building, 21 Sassoon Road, Hong Kong, China. Phone: 852-2819-2867; Fax: 852-2817-0857; E-mail: xhwang{at}hkucc.hku.hk.

Recently, mitotic arrest deficient 2 (MAD2)–mediated spindle checkpoint is shown to induce mitotic arrest in response to DNA damage, indicating overlapping roles of the spindle checkpoint and DNA damage checkpoint. In this study, we investigated if MAD2 played a part in cellular sensitivity to DNA-damaging agents, especially cisplatin, and whether it was regulated through mitotic checkpoint. Using nine nasopharyngeal carcinoma (NPC) cell lines, we found that decreased MAD2 expression was correlated with cellular resistance to cisplatin compared with the cell lines with high levels of MAD2. Exogenous MAD2 expression in NPC cells also conferred sensitivity to DNA-damaging agents especially cisplatin but not other anticancer drugs with different mechanisms of action. The increased cisplatin sensitivity in MAD2 transfectants was associated with mitotic arrest and activation of apoptosis pathway evidenced by the increased mitotic index and apoptosis rate as well as decreased Bcl-2 and Bax ratio and expression of cleaved poly(ADP-ribose) polymerase and caspase 3. Our results indicate that the MAD2-induced chemosensitization to cisplatin in NPC cells is mediated through the induction of mitotic arrest, which in turn activates the apoptosis pathway. Our evidence further confirms the previous hypothesis that spindle checkpoint plays an important part in DNA damage-induced cell cycle arrest and suggests a novel role of MAD2 in cellular sensitivity to cisplatin.

Key Words: MAD2 • cisplatin • sensitivity • apoptosis • cell cycle checkpoints • mechanisms of drug action/new molecular target/therapeutics • cell cycle mechanisms of anticancer drug action • effectors of apoptosis

This article has been cited by other articles:

				A.-L. Cheng, W.-G. Huang, Z.-C. Chen, F. Peng, P.-F. Zhang, M.-Y. Li, F. Li, J.-L. Li, C. Li, H. Yi, et al. Identification of Novel Nasopharyngeal Carcinoma Biomarkers by Laser Capture Microdissection and Proteomic Analysis Clin. Cancer Res., January 15, 2008; 14(2): 435 - 445. [Abstract] [Full Text] [PDF]

				J. Xu, H. Peng, Q. Chen, Y. Liu, Z. Dong, and J.-T. Zhang Oligomerization Domain of the Multidrug Resistance-Associated Transporter ABCG2 and Its Dominant Inhibitory Activity Cancer Res., May 1, 2007; 67(9): 4373 - 4381. [Abstract] [Full Text] [PDF]

				H. W. Cheung, A. C.S. Chun, Q. Wang, W. Deng, L. Hu, X.-Y. Guan, J. M. Nicholls, M.-T. Ling, Y. Chuan Wong, S. Wah Tsao, et al. Inactivation of Human MAD2B in Nasopharyngeal Carcinoma Cells Leads to Chemosensitization to DNA-Damaging Agents. Cancer Res., April 15, 2006; 66(8): 4357 - 4367. [Abstract] [Full Text] [PDF]