The over-expression of p53 H179Y residue mutation causes the increase of cyclin A1 and Cdk4 expression in HELF cells.
Down-regulation of p53 expression has been found in a broad range of human cancers and cell proliferation disorders, indicating that p53 plays a key role in cell cycle regulation and tumor suppression. In our current study, we transfected human embryonic lung fibroblast (HELF) cells with pcDNA3-wild-type p53 (pcDNA3-wtp53) plasmid, or pcDNA3-H179Y-mutated p53 (pcDNA3-mtp53) plasmid that mimics the mutation found in some human lung tumors, and further studied the role of p53 in the regulation of cell proliferation. Over expression of wild-type p53 caused cell cycle arrest at G1 phase with reduced cell size, decreased expression of cyclin D3, cyclin E, Cdk2 and Cdk4, and increased expression of p21. In contrast, over expression of H179Y-mutant p53 promoted G1 to S phase transition with enlarged cell size and increased cyclin A1 and Cdk4 expression in HELF cells. These results indicate that mutation at the p53 H179Y residue up-regulates cyclin A1 and Cdk4 expression, and promotes HELF cell proliferation.
Yang
Di
D
Department of Pharmacology and Toxicology, College of Veterinary Medicine, China Agricultural University, Beijing 100094, P.R. China.
Qi
Yitao
Y
Chen
Qian
Q
Wang
Zhiqin
Z
Jin
Xi
X
Gao
Jie
J
Fu
Juanling
J
Xiao
Xilong
X
Zhou
Zongcan
Z
D049109:Cell Proliferation; D002478:Cells, Cultured; D019925:Cyclin A / Q000235:genetics*; D056750:Cyclin A1; D051358:Cyclin-Dependent Kinase 4 / Q000235:genetics*; D005347:Fibroblasts / Q000166:cytology; D016158:Genes, p53; D006801:Humans; D008168:Lung / Q000166:cytology / Q000196:embryology; D017354:Point Mutation; D014162:Transfection; D015854:Up-Regulation
C503745:CCNA1 protein, human; D019925:Cyclin A; D056750:Cyclin A1; C495900:CDK4 protein, human; D051358:Cyclin-Dependent Kinase 4