title: Nutlin-3 protects kidney cells during cisplatin therapy by suppressing Bax/Bak activation.
abstract: Nutlins, the newly developed small molecule antagonists of MDM2, activate p53 and induce apoptosis in cancer cells, offering a novel strategy of chemotherapy. Recent studies have further suggested synergistic effects of nutlins with other chemotherapeutic drugs. However, it is unclear whether nutlins increase or decrease the side effects of these drugs in normal non-malignant cells or tissues. Cisplatin is a widely used chemotherapy drug, which has a major side effect of kidney injury. Here we show that Nutlin-3 protected kidney cells against cisplatin-induced apoptosis. The cytoprotective effects of Nutlin-3 were not related to its regulation of p53 or consequent gene expression during cisplatin treatment. Moreover, the protective effects were shown in MDM2-, MDM4-, or p53-deficient cells. On the other hand, Nutlin-3 suppressed mitochondrial events of apoptosis during cisplatin incubation, including Bax activation and cytochrome c release. Nutlin-3 attenuated cisplatin-induced oligomerization of Bax and Bak but not their interactions with Bcl-XL. In isolated mitochondria, Nutlin-3 inhibited cytochrome c release induced by Ca2+, Bim peptide, and recombinant tBid. Importantly, it blocked both Bax and Bak oligomerization under these conditions. Together, the results have uncovered a new pharmacological function of nutlins, i.e. suppression of Bax and Bak, two critical mediators of apoptosis.
authors.affiliation: Department of Cellular Biology and Anatomy, Medical College of Georgia and Veterans Affairs Medical Center, Augusta, Georgia 30912, USA.
authors.forename: Man
authors.initials: M
authors.lastname: Jiang
authors.forename: Navjotsin
authors.initials: N
authors.lastname: Pabla
authors.forename: Robert F
authors.initials: RF
authors.lastname: Murphy
authors.forename: Tianxin
authors.initials: T
authors.lastname: Yang
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Yin
authors.forename: Kurt
authors.initials: K
authors.lastname: Degenhardt
authors.forename: Eileen
authors.initials: E
authors.lastname: White
authors.forename: Zheng
authors.initials: Z
authors.lastname: Dong
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000009:adverse effects*; D017209:Apoptosis / Q000187:drug effects; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D000072224:Bcl-2-Like Protein 11; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D002945:Cisplatin / Q000009:adverse effects*; D045304:Cytochromes c / Q000037:antagonists & inhibitors; D004336:Drug Antagonism; D007093:Imidazoles / Q000494:pharmacology*; D007687:Kidney Tubules, Proximal / Q000187:drug effects* / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D009369:Neoplasms / Q000188:drug therapy / Q000473:pathology; D010879:Piperazines / Q000494:pharmacology*; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051736:Proto-Oncogene Proteins c-mdm2 / Q000037:antagonists & inhibitors*; D051381:Rats; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D050998:bcl-2 Homologous Antagonist-Killer Protein / Q000037:antagonists & inhibitors; D051028:bcl-2-Associated X Protein / Q000037:antagonists & inhibitors
chemical_list: D000970:Antineoplastic Agents; D051017:Apoptosis Regulatory Proteins; D000072224:Bcl-2-Like Protein 11; C000606778:Bcl2l11 protein, rat; D007093:Imidazoles; D008565:Membrane Proteins; D010879:Piperazines; D011518:Proto-Oncogene Proteins; D016159:Tumor Suppressor Protein p53; D050998:bcl-2 Homologous Antagonist-Killer Protein; D051028:bcl-2-Associated X Protein; C482205:nutlin 3; D045304:Cytochromes c; D051736:Proto-Oncogene Proteins c-mdm2; D002945:Cisplatin; D002118:Calcium