title: Overexpression of p21Waf1 induces apoptosis in immortalized human vascular smooth muscle cells.
abstract: To understand the role of the cell cycle regulatory protein in the control of smooth muscle cell (SMC) proliferation, we tested the overexpression of p21Waf1, a cyclin-dependent kinase inhibitor, in human normal (MS9) and immortalized SMCs (ISS10) transfected with ori-minus simian virus 40 DNA, using an adenovirus-mediated system. In MS9, overexpression of p21Waf1 resulted in the inhibition of cell cycle progression at the G1/S boundary without apoptosis. On the other hand, in ISS10, overexpression of p21Waf1 induced marked apoptosis. In these cells, immunohistochemistry revealed that overexpressed p21Waf1 was localized in the nucleus. No differential expression pattern of either p53 or SV40T was observed in p21Waf1- and control gene (beta-galactosidase)-infected cells. Old-passaged ISS10 cells eventually showed growth arrest and a senescent-like phenotype. Immunohistochemistry revealed that p21Waf1 was localized in the cytoplasm of the early-passaged cells, but was found in the nucleus of the old-passaged cells. Our data suggested that nuclear accumulation of p21Waf1 plays a role in the cell death of immortalized SMC, which carries dysfunction of the cell cycle regulatory proteins such as p53. This culture model may be useful for studying the process of SMC proliferation, cell death, senescence, and cell cycle regulation.
authors.affiliation: Department of Pathology, Kurume University, School of Medicine, Fukuoka, Japan. seikato@med.kurume-u.ac.jp
authors.forename: Seiya
authors.initials: S
authors.lastname: Kato
authors.forename: Seiji
authors.initials: S
authors.lastname: Ueda
authors.forename: Miki
authors.initials: M
authors.lastname: Yamaguchi
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Miyamoto
authors.forename: Teruhiko
authors.initials: T
authors.lastname: Fujii
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Izumaru
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Kume
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Toyozumi
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Arima
authors.forename: Minoru
authors.initials: M
authors.lastname: Morimatsu
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000952:Antigens, Polyomavirus Transforming / Q000235:genetics / Q000378:metabolism*; D017209:Apoptosis; D015153:Blotting, Western; D002455:Cell Division / Q000502:physiology; D002460:Cell Line; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000378:metabolism*; D016158:Genes, p53 / Q000502:physiology*; D006801:Humans; D007150:Immunohistochemistry; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D010641:Phenotype; D014162:Transfection
chemical_list: D000952:Antigens, Polyomavirus Transforming; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins