Adenovirus-mediated wild-type-p53-gene expression sensitizes TNF-resistant tumor cells to TNF-induced cytotoxicity by altering the cellular redox state.
We have shown that the loss of p53 function contributed to resistance of tumor cells to TNF-induced cytotoxicity. In the present study, we evaluated the effect of wild-type p53 (wt-p53) expression on TNF sensitivity, by introducing wt-p53 into MCF7/Adr cells in which p53 was deleted, via a recombinant adenovirus encoding p53 (Ad-p53). Our results indicate that infection with Ad-p53 (50-100 viral particles per cell) resulted in pronounced cytotoxicity, whereas infection with 10 viral particles per cell, which was weakly toxic for the MCF7/Adr cells, sensitized these cells to TNF-induced cell death. Moreover, expression of wt-p53 in MCF7/Adr cells induced the production of reactive oxygen intermediates (ROIs) and caused glutathione (GSH) depletion, indicating disturbances in the cellular redox state. Additional treatment of cells with the anti-oxidant and glutathione (GSH) precursor N-acetylcysteine (NAC) resulted in inhibition of p53-induced ROIs production and in partial restoration of intracellular GSH levels, which was associated with the ability of NAC to inhibit p53-modulated TNF-induced cytotoxicity. Interestingly, Ad-p53 was able to inhibit TNF-induced MnSOD mRNA expression in MCF7/Adr cells, which might contribute to the sensitization of cells to the cytotoxic action of TNF. Taken together, our data strongly suggest that wt-p53 expression sensitizes TNF-resistant MCF7 cells with p53 deletion to TNF-induced cell death by a pathway that is dependent on ROIs production.
Shatrov
V A
VA
INSERM U487, "Cytokines et Immunologie des Tumeurs Humaines," Institut Gustave Roussy, Villejuif, France.
Ameyar
M
M
Bouquet
C
C
Cai
Z
Z
Stancou
R
R
Haddada
H
H
Chouaib
S
S
D000111:Acetylcysteine / Q000494:pharmacology; D000256:Adenoviridae / Q000235:genetics*; D001943:Breast Neoplasms / Q000201:enzymology / Q000235:genetics / Q000473:pathology / Q000821:virology; D003588:Cytopathogenic Effect, Viral; D015536:Down-Regulation / Q000187:drug effects; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D005260:Female; D015870:Gene Expression / Q000187:drug effects*; D005822:Genetic Vectors / Q000235:genetics / Q000494:pharmacology*; D006801:Humans; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D016159:Tumor Suppressor Protein p53 / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics*
D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; D016159:Tumor Suppressor Protein p53; D013482:Superoxide Dismutase; D000111:Acetylcysteine