title: Endoreduplication of human smooth muscle cells induced by 2-methoxyestradiol: a role for cyclin-dependent kinase 2.
abstract: Endoreduplication has been suggested to contribute to the development of hypertrophy of smooth muscle cells (SMCs) in hypertension. However, endoreduplication in vascular SMCs and the underlying molecular mechanisms are not clear. Treatment of human SMCs with 10 microM 2-methoxyestradiol (2-ME) for 24 h induces accumulation of cells with > or =4N DNA content, and some polyploid/aneuploid cells actively synthesize their DNA, suggesting the occurrence of endoreduplication. In addition, 2-ME treatment upregulates the expression of cyclin-dependent kinase 2 (Cdk2). The present study was designed to characterize endoreduplication of human SMCs and explore the potential roles of Cdk2 in endoreduplication induced by 2-ME. Treatment with 2-ME (10 microM) for 2-4 days not only caused increases in >4N cells and their reentry into S phase but also induced overduplication of chromosomes. Furthermore, 2-ME increased the kinase activity of Cdk2 and its interaction with cyclin E. Inducible overexpression of dominant-negative Cdk2 in human SMCs inhibited both DNA synthesis of >4N cells and the accumulation of >4N cells induced by 2-ME. We conclude that 2-ME induces endoreduplication of human SMCs and Cdk2 plays an important role in endoreduplication in response to 2-ME.
authors.affiliation: Smooth Muscle Research Group, Department of Biochemistry and Molecular Biology, Faculty of Medicine, Univ of Calgary, Calgary, Alberta, Canada.
authors.forename: Yu
authors.initials: Y
authors.lastname: Gui
authors.forename: Hao
authors.initials: H
authors.lastname: Yin
authors.forename: Jia-Yin
authors.initials: JY
authors.lastname: He
authors.forename: Song-Hua
authors.initials: SH
authors.lastname: Yang
authors.forename: Michael P
authors.initials: MP
authors.lastname: Walsh
authors.forename: Xi-Long
authors.initials: XL
authors.lastname: Zheng
mesh_terms: D000077584:2-Methoxyestradiol; D000782:Aneuploidy; D001011:Aorta; D002455:Cell Division / Q000187:drug effects; D051357:Cyclin-Dependent Kinase 2 / Q000235:genetics*; D004261:DNA Replication / Q000187:drug effects; D004958:Estradiol / Q000031:analogs & derivatives* / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D006973:Hypertension / Q000473:pathology; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology
chemical_list: D004958:Estradiol; D000077584:2-Methoxyestradiol; D051357:Cyclin-Dependent Kinase 2