Influence of p53 and p21(WAF1) expression on sensitivity of cancer cells to cladribine

• Published in: Biochemical pharmacology 2003-01, Vol.65 (1), p.121-129
• Main Authors: Galmarini, Carlos María, Voorzanger, Nathalie, Falette, Nicole, Jordheim, Lars, Cros, Emeline, Puisieux, Alain, Dumontet, Charles
• Format: Article
• Language: English
• Subjects: Antineoplastic Agents - pharmacology; Apoptosis; Blotting, Northern; Blotting, Western; Cell Cycle - drug effects; Cell Survival - drug effects; Cladribine - pharmacology; Cyclin-Dependent Kinase Inhibitor p21; Cyclins - metabolism; Drug Screening Assays, Antitumor; Gene Expression - drug effects; Humans; Necrosis; Reverse Transcriptase Polymerase Chain Reaction; Tumor Cells, Cultured; Tumor Suppressor Protein p53 - metabolism
• ISSN: 0006-2952
• DOI: 10.1016/S0006-2952(02)01448-X

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.