Transfection with mutant p53 gene inhibits heat-induced apoptosis in a head and neck cell line of human squamous cell carcinoma.
OBJECTIVE
To confirm that human cancer cells show p53-dependent heat sensitivity through an apoptosis-related mechanism, we examined the heat sensitivity and Bax-mediated apoptosis after heating in a human squamous cell carcinoma cell line, SAS, with identical genetic backgrounds except for the p53 status.


METHODS
We performed colony formation assay, Western blotting and analyses of apoptosis, using the SAS cells transfected with pC53-248 vector with mutant p53 gene (SAS/Trp248 cells) or the cells transfected with pCMV-Neo-Bam vector (SAS/neo cells) as a control.


RESULTS
SAS/Trp248 cells showed heat resistance due to the dominant negative nature of mp53, compared with SAS/neo cells. The incidence of DNA ladders and apoptotic bodies increased markedly after heating in SAS/neo cells, but increased very little in SAS/Trp248 cells.


CONCLUSIONS
These results suggest that heat resistance brought by mp53-transfection is p53-dependent and closely correlates with the induction of apoptosis in human squamous cell carcinomas.
Ota
I
I
Department of Otorhinolaryngology, Nara Medical University, Kashihara, Nara, Japan.
Ohnishi
K
K
Takahashi
A
A
Yane
K
K
Kanata
H
H
Miyahara
H
H
Ohnishi
T
T
Hosoi
H
H
D017209:Apoptosis / Q000235:genetics / Q000502:physiology*; D015153:Blotting, Western; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000503:physiopathology* / Q000628:therapy; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002470:Cell Survival; D053938:DNA Fragmentation; D004789:Enzyme Activation; D005786:Gene Expression Regulation; D016158:Genes, p53 / Q000502:physiology*; D005822:Genetic Vectors / Q000235:genetics; D006258:Head and Neck Neoplasms / Q000235:genetics / Q000503:physiopathology* / Q000628:therapy; D006801:Humans; D006979:Hyperthermia, Induced; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D014407:Tumor Cells, Cultured; D014410:Tumor Stem Cell Assay; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D051028:bcl-2-Associated X Protein
C494826:BAX protein, human; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases