title: Disruption of the MDM2-p53 interaction strongly potentiates p53-dependent apoptosis in cisplatin-resistant human testicular carcinoma cells via the Fas/FasL pathway.
abstract: Wild-type p53 has a major role in the response and execution of apoptosis after chemotherapy in many cancers. Although high levels of wild-type p53 and hardly any TP53 mutations are found in testicular cancer (TC), chemotherapy resistance is still observed in a significant subgroup of TC patients. In the present study, we demonstrate that p53 resides in a complex with MDM2 at higher cisplatin concentrations in cisplatin-resistant human TC cells compared with cisplatin-sensitive TC cells. Inhibition of the MDM2-p53 interaction using either Nutlin-3 or MDM2 RNA interference resulted in hyperactivation of the p53 pathway and a strong induction of apoptosis in cisplatin-sensitive and -resistant TC cells. Suppression of wild-type p53 induced resistance to Nutlin-3 in TC cells, demonstrating the key role of p53 for Nutlin-3 sensitivity. More specifically, our results indicate that p53-dependent induction of Fas membrane expression (∼threefold) and enhanced Fas/FasL interactions at the cell surface are important mechanisms of Nutlin-3-induced apoptosis in TC cells. Importantly, an analogous Fas-dependent mechanism of apoptosis upon Nutlin-3 treatment is executed in wild-type p53 expressing Hodgkin lymphoma and acute myeloid leukaemia cell lines. Finally, we demonstrate that Nutlin-3 strongly augmented cisplatin-induced apoptosis and cell kill via the Fas death receptor pathway. This effect is most pronounced in cisplatin-resistant TC cells.
authors.affiliation: Department of Medical Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: Koster
authors.forename: H
authors.initials: H
authors.lastname: Timmer-Bosscha
authors.forename: R
authors.initials: R
authors.lastname: Bischoff
authors.forename: J A
authors.initials: JA
authors.lastname: Gietema
authors.forename: S
authors.initials: S
authors.lastname: de Jong
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology*; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000378:metabolism; D019008:Drug Resistance, Neoplasm; D004357:Drug Synergism; D053222:Fas Ligand Protein / Q000378:metabolism*; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D047468:Immunoprecipitation; D008297:Male; D009154:Mutation; D010879:Piperazines / Q000494:pharmacology; D011485:Protein Binding / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D051736:Proto-Oncogene Proteins c-mdm2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D015398:Signal Transduction / Q000187:drug effects; D013736:Testicular Neoplasms / Q000378:metabolism / Q000473:pathology*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects; D019014:fas Receptor / Q000235:genetics / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; C491901:FAS protein, human; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D007093:Imidazoles; D010879:Piperazines; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D019014:fas Receptor; C482205:nutlin 3; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2; D002945:Cisplatin