Effects of ectopic overexpression of p21(WAF1/CIP1) on aneuploidy and the malignant phenotype of human brain tumor cells.
p21WAF1/CIP1 is a downstream effector of the p53 tumor suppressor gene and a universal cyclin-dependent kinase (CDK) inhibitor. To determine the ability of p21WAF1/CIP1 to function as a tumor suppressor, we constructed a replication-defective adenovirus vector containing p21WAF1/CIP1 (Adp21WAF1/CIP1) to effect ectopic overexpression in a p53-defective human astrocytoma cell line, U-373MG. We observed a marked decrease in CDC2 and CDK2 kinase activity associated with a corresponding decrease in the amount of CDC2 but not CDK2 protein; a decreased growth potential of Adp21WAF1/CIP1-infected cells demonstrated by diminished [3H]thymidine incorporation, increased cell doubling time and G1-arrested cell cycle; an association between Adp21WAF1/CIP1-infected cells and inhibition of aneuploid cell accumulation; and an alteration of the malignant phenotype of cells was evidenced by the loss of anchorage-independent growth in soft agar and the failure to induce tumorigenesis in both peripheral and intracerebral xenograft models, including the prevention of tumor formation Adp21WAF1/CIP1 infection 2 days post tumor cell implantation. Adp21WAF1/CIP1. Adp21WAF1/CIP1 appears to be a strong candidate for gene therapy studies based on these studies indicating that Adp21WAF1/CIP1 inhibits proliferation, tumorigenicity and aneuploidy in human brain tumor cells.
Chen
J
J
Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas 75235-9063, USA.
Willingham
T
T
Shuford
M
M
Bruce
D
D
Rushing
E
E
Smith
Y
Y
Nisen
P D
PD
D000782:Aneuploidy; D000818:Animals; D017209:Apoptosis; D001254:Astrocytoma / Q000235:genetics / Q000378:metabolism* / Q000628:therapy*; D001932:Brain Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000628:therapy*; D018797:Cell Cycle Proteins / Q000378:metabolism; D002455:Cell Division / Q000235:genetics; D050759:Cyclin-Dependent Kinase Inhibitor p21; D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D016213:Cyclins / Q000378:metabolism* / Q000502:physiology; D003673:Defective Viruses; D016193:G1 Phase / Q000502:physiology; D016158:Genes, p53 / Q000502:physiology; D015316:Genetic Therapy; D005822:Genetic Vectors; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D010641:Phenotype; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured
C493956:CDKN1A protein, human; C493957:Cdkn1a protein, mouse; D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D018844:Cyclin-Dependent Kinases