Cisplatinum and taxol induce different patterns of p53 phosphorylation.
Posttranslational modifications of p53 induced by two widely used anticancer agents, cisplatinum (DDP) and taxol were investigated in two human cancer cell lines. Although both drugs were able to induce phosphorylation at serine 20 (Ser20), only DDP treatment induced p53 phosphorylation at serine 15 (Ser15). Moreover, both drug treatments were able to increase p53 levels and consequently the transcription of waf1 and mdm-2 genes, although DDP treatment resulted in a stronger inducer of both genes. Using two ataxia telangiectasia mutated (ATM) cell lines, the role of ATM in drug-induced p53 phosphorylations was investigated. No differences in drug-induced p53 phosphorylation could be observed, indicating that ATM is not the kinase involved in these phosphorylation events. In addition, inhibition of DNA-dependent protein kinase activity by wortmannin did not abolish p53 phosphorylation at Ser15 and Ser20, again indicating that DNA-PK is unlikely to be the kinase involved. After both taxol and DDP treatments, an activation of hCHK2 was found and this is likely to be responsible for phosphorylation at Ser20. In contrast, only DDP was able to activate ATR, which is the candidate kinase for phosphorylation of Ser15 by this drug. This data clearly suggests that differential mechanisms are involved in phosphorylation and activation of p53 depending on the drug type.
Damia
G
G
Laboratory of Molecular Pharmacology, Department of Oncology, Istituto di Ricerche Farmacologiche Mario Negri, via Eritrea 62, 20157 Milan, Italy. damia@irfmn.mnegri.it
Filiberti
L
L
Vikhanskaya
F
F
Carrassa
L
L
Taya
Y
Y
D'incalci
M
M
Broggini
M
M
D000730:Androstadienes / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology*; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D064007:Ataxia Telangiectasia Mutated Proteins; D015153:Blotting, Western; D018797:Cell Cycle Proteins / Q000378:metabolism; D002945:Cisplatin / Q000494:pharmacology*; D003110:Colonic Neoplasms / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000378:metabolism; D051747:DNA-Activated Protein Kinase; D004268:DNA-Binding Proteins; D005260:Female; D006801:Humans; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009687:Nuclear Proteins; D010051:Ovarian Neoplasms / Q000378:metabolism; D017239:Paclitaxel / Q000494:pharmacology*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051736:Proto-Oncogene Proteins c-mdm2; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D000077191:Wortmannin
D000730:Androstadienes; D000970:Antineoplastic Agents; D000972:Antineoplastic Agents, Phytogenic; C493956:CDKN1A protein, human; D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011518:Proto-Oncogene Proteins; D016159:Tumor Suppressor Protein p53; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D051747:DNA-Activated Protein Kinase; C497263:PRKDC protein, human; D017346:Protein Serine-Threonine Kinases; D020928:Mitogen-Activated Protein Kinases; D017239:Paclitaxel; D002945:Cisplatin; D000077191:Wortmannin