title: Influence of p53 and p21(WAF1) expression on sensitivity of cancer cells to cladribine.
abstract: The present study was performed to gain insight into the role of p53 and p21(WAF1) on the cytotoxicity of the purine analogue cladribine (2-CdA) on cancer cells. Drug sensitivity, cell cycle distribution and drug-induced cell death were compared in three lines derived from the colorectal carcinoma HCT116: the p53+/+ cell line containing wild-type p53 and the p53-/- and p21(WAF1)-/- lines, in which both alleles of p53 or p21(WAF1) were deleted by homologous recombination, respectively. p53-/- and p21(WAF1)-/- cells were significantly more resistant to the cytotoxic effects of 2-CdA than the p53+/+ cells. p53+/+ cells and p21(WAF1)-/-, but not p53-/- cells, displayed wt-p53 protein accumulation and arrested in S-phase after exposure to 2-CdA. mRNA analysis of the transporter hENT1 and of enzymes involved in drug metabolism did not show alterations which might explain a drug-resistant phenotype in the p53-/- or p21(WAF1)-/- cells. Exposure of p53+/+ cells to 2-CdA resulted in expression of p21(WAF1) mRNA and protein, enhanced expression of uncleaved PARP-1, and a higher degree both of apoptosis and necrosis than in p53-/- and p21(WAF1)-/- cells exposed to 2-CdA. Addition of the specific PARP-1 inhibitor 3-AB to 2-CdA-treated cells rendered p53+/+ cells resistant to this drug. Bax levels were reduced in the p53-/- while they increased in the p53+/+ line and remained stable in the p21(WAF1)-/- cells. We conclude that p53 and p21(WAF1) status of cancer cells influences their sensitivity to 2-CdA cytotoxicity. This may involve alterations in the apoptotic cascade as well as in PARP-1-dependent cell death.
authors.affiliation: INSERM 453. 8 Avenue Rockefeller, 69373 Lyon Cedex 08, France. fgalma@rockefeller.univ-lyon1.fr
authors.forename: Carlos María
authors.initials: CM
authors.lastname: Galmarini
authors.forename: Nathalie
authors.initials: N
authors.lastname: Voorzanger
authors.forename: Nicole
authors.initials: N
authors.lastname: Falette
authors.forename: Lars
authors.initials: L
authors.lastname: Jordheim
authors.forename: Emeline
authors.initials: E
authors.lastname: Cros
authors.forename: Alain
authors.initials: A
authors.lastname: Puisieux
authors.forename: Charles
authors.initials: C
authors.lastname: Dumontet
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis; D015152:Blotting, Northern; D015153:Blotting, Western; D002453:Cell Cycle / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D017338:Cladribine / Q000494:pharmacology*; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000378:metabolism*; D004354:Drug Screening Assays, Antitumor; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D009336:Necrosis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D016159:Tumor Suppressor Protein p53; D017338:Cladribine