TY - JOUR
T1 - p53, p21(WAF1/CIP1), and MDM2 involvement in proliferation and apoptosis in an in vitro model of conditionally immortalized human vascular smooth muscle cells
AU - Hsieh, J. Kuang
AU - Kletsas, Dimitris
AU - Clunn, Gerard
AU - Hughes, Alun D.
AU - Schachter, Michael
AU - Demoliou-Mason, Catherine
PY - 2000/3
Y1 - 2000/3
N2 - Using an in vitro model of a conditionally immortalized cell line, we investigated how human vascular smooth muscle cells (VSMCs) are affected by the expression of simian virus 40 (SV40) large T antigen (LT antigen), which binds to cell cycle regulators, such as the tumor suppressor protein p53. Cells were obtained after infection of saphenous vein-derived VSMCs with a nonreplicative retroviral vector containing a temperature-sensitive (ts) mutant of SV40 LT antigen and were shown to have maintained some characteristics and responses of VSMCs. Under permissive temperature conditions (36°C), the increased rate of cell proliferation was shown to be associated with expression of LT antigen and with LT-antigen binding to and inactivation of p53. p53 inactivation failed to block apoptosis induced by serum withdrawal or by UV irradiation. Downregulation of LT-antigen expression at the nonpermissive temperature (39°C) was shown to be associated with growth arrest, increased expression of the cell cycle inhibitor p21(WAF1/CIP1), increased MDM2-promoter activity, and differential expression of MDM2 gene products, suggesting that p53-induced transcription/transactivation may be involved in VSMC cell cycle control but not necessarily apoptosis. The established SMC line HVTs-SM1 may be a useful model for the study of processes involved in myointimal hyperplasia and cellular aging, as well as for the study of cell cycle control in general.
AB - Using an in vitro model of a conditionally immortalized cell line, we investigated how human vascular smooth muscle cells (VSMCs) are affected by the expression of simian virus 40 (SV40) large T antigen (LT antigen), which binds to cell cycle regulators, such as the tumor suppressor protein p53. Cells were obtained after infection of saphenous vein-derived VSMCs with a nonreplicative retroviral vector containing a temperature-sensitive (ts) mutant of SV40 LT antigen and were shown to have maintained some characteristics and responses of VSMCs. Under permissive temperature conditions (36°C), the increased rate of cell proliferation was shown to be associated with expression of LT antigen and with LT-antigen binding to and inactivation of p53. p53 inactivation failed to block apoptosis induced by serum withdrawal or by UV irradiation. Downregulation of LT-antigen expression at the nonpermissive temperature (39°C) was shown to be associated with growth arrest, increased expression of the cell cycle inhibitor p21(WAF1/CIP1), increased MDM2-promoter activity, and differential expression of MDM2 gene products, suggesting that p53-induced transcription/transactivation may be involved in VSMC cell cycle control but not necessarily apoptosis. The established SMC line HVTs-SM1 may be a useful model for the study of processes involved in myointimal hyperplasia and cellular aging, as well as for the study of cell cycle control in general.
KW - Cell line
KW - MDM2
KW - p21(WAF1/CIP1)
KW - p53
KW - SV-40
KW - Vascular smooth muscle
UR - http://www.scopus.com/inward/record.url?scp=0034021808&partnerID=8YFLogxK
M3 - Article
C2 - 10712385
AN - SCOPUS:0034021808
SN - 1079-5642
VL - 20
SP - 636
EP - 644
JO - Arteriosclerosis, Thrombosis, and Vascular Biology
JF - Arteriosclerosis, Thrombosis, and Vascular Biology
IS - 3
ER -