DNA damage-associated dysregulation of the cell cycle and apoptosis control in cells with germ-line p53 mutation.
Lymphoblastoid cell lines (LCLs) with heterozygous p53 mutations at residues 286A, 133R, 282W, 132E, and 213ter were established from five independent Li-Fraumeni syndrome families. When cell cycle regulation in response to gamma-irradiation was studied, these LCLs showed an abnormal G1 checkpoint associated with defective inhibition of cyclin E/cyclin-dependent kinase 2 activity in all cases except for 282W LCL, which showed a normal G1 checkpoint. On the other hand, the control of S-phase-G2 as determined by cyclin A/cyclin-dependent kinase 2 activity was defective in all these LCLs. The mitotic checkpoint was also defective in the two LCLs analyzed as either competent or incompetent for G1 arrest. When radiation-induced apoptosis, which requires wild-type p53 function under optimal conditions, was studied, all of these LCLs showed significant failure compared to normal LCLs. These findings indicate that although p53-dependent transactivation and G1-S-phase cell cycle control are variably dysregulated, the induction of apoptosis and control of the cell cycle at S-phase-G2 and the mitotic checkpoint in response to DNA-damaging agents are consistently dysregulated in heterozygous mutant LCLs. This suggests that these dysfunctions underlie, at least in part, the susceptibility of Li-Fraumeni syndrome families to cancer. Furthermore, the approach presented is a potentially useful method for studying individual carriers of different germ-line p53 mutations and different biological features.
Goi
K
K
Department of Virology, The National Children's Medical Research Center, Setagaya-ku, Tokyo, Japan.
Takagi
M
M
Iwata
S
S
Delia
D
D
Asada
M
M
Donghi
R
R
Tsunematsu
Y
Y
Nakazawa
S
S
Yamamoto
H
H
Yokota
J
J
Tamura
K
K
Saeki
Y
Y
Utsunomiya
J
J
Takahashi
T
T
Ueda
R
R
Ishioka
C
C
Eguchi
M
M
Kamata
N
N
Mizutani
S
S
D000293:Adolescent; D000328:Adult; D000483:Alleles; D017209:Apoptosis / Q000502:physiology* / Q000528:radiation effects; D042846:CDC2-CDC28 Kinases; D002453:Cell Cycle / Q000502:physiology; D016923:Cell Death / Q000528:radiation effects; D002472:Cell Transformation, Viral; D002675:Child, Preschool; D051357:Cyclin-Dependent Kinase 2; D050759:Cyclin-Dependent Kinase Inhibitor p21; D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D016213:Cyclins / Q000096:biosynthesis / Q000378:metabolism; D004249:DNA Damage; D004198:Disease Susceptibility; D005260:Female; D015870:Gene Expression; D016158:Genes, p53; D018095:Germ-Line Mutation; D004854:Herpesvirus 4, Human; D006801:Humans; D016864:Li-Fraumeni Syndrome / Q000097:blood / Q000235:genetics* / Q000473:pathology*; D008214:Lymphocytes / Q000166:cytology / Q000502:physiology / Q000528:radiation effects; D008297:Male; D010641:Phenotype; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D015533:Transcriptional Activation; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis / Q000502:physiology
C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D016159:Tumor Suppressor Protein p53; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases