Resistance of MCF7 human breast carcinoma cells to TNF-induced cell death is associated with loss of p53 function.
We have investigated the relationship between the development of tumor resistance towards the cytotoxic action of tumor necrosis factor-alpha (TNF) and p53 function, using the TNF-sensitive MCF7 human breast adenocarcinoma cell line and two TNF-resistant sublines, MCF7/R-A1 and MCF7/Adr. Use of single-strand conformation polymorphism (SSCP) analysis and DNA sequencing shows that MCF7 has a wild-type p53 gene, whereas both TNF-resistant sublines exhibit mutant p53. This includes a point mutation R280K in MCF7/R-A1 cells, and a point mutation at the splicing acceptor site on the upstream border of exon 5 resulting in a 21 pb deletion in MCF7/Adr cells. These mutations result in loss of p53 capacity to transactivate FASAY (functional assay in yeast). In contrast to what is observed for parental MCF7 cells, treatment of resistant sublines with TNF or gamma-irradiation fails neither to induce the expression of the p53-regulated gene products p21waf1/CIP1 and MDM2, nor to arrest the cells in the G1 phase of the cell cycle. Disruption of p53 wild-type function in MCF7 cells by transfection with human papillomavirus type-16 E6 gene, leads to abrogation of the cytotoxic, but not the cytostatic activity of TNF. Altogether, our results strongly suggest that wild-type p53 is involved in cytotoxic action of TNF, and point out that loss of p53 function contributes to resistance of tumor cell to TNF-induced killing.
Cai
Z
Z
INSERM CJF 94-11 Cytokines et Immunité Antitumorale, Institut Gustave-Roussy, Villejuif, France.
Capoulade
C
C
Moyret-Lalle
C
C
Amor-Gueret
M
M
Feunteun
J
J
Larsen
A K
AK
Paillerets
B B
BB
Chouaib
S
S
D017209:Apoptosis / Q000187:drug effects*; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology*; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000235:genetics; D019008:Drug Resistance, Neoplasm; D016193:G1 Phase / Q000187:drug effects / Q000528:radiation effects; D005814:Genes, Viral; D016158:Genes, p53; D006801:Humans; D009154:Mutation; D009687:Nuclear Proteins; D027383:Papillomaviridae / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics; D051736:Proto-Oncogene Proteins c-mdm2; D015533:Transcriptional Activation; D014162:Transfection; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis; D015678:Viral Structural Proteins / Q000235:genetics
C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D014409:Tumor Necrosis Factor-alpha; D016159:Tumor Suppressor Protein p53; D015678:Viral Structural Proteins; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2