title: The p53 stabilizing compound CP-31398 induces apoptosis by activating the intrinsic Bax/mitochondrial/caspase-9 pathway.
abstract: p53 is considered the guardian of the genome and has a number of biological functions, including cell cycle arrest, DNA repair, and apoptosis. In a recent study by Foster and colleagues, the pharmacological compound CP-31398 was found to stabilize wild-type p53 to enhance its transcriptional activity and inhibit tumor growth in mice. We hypothesize that CP-31398 induces apoptosis by stabilizing the p53 protein and activating the mitochondrial-mediated pathway. Using the wild-type p53 HCT116+/+ and the p53-deficient HCT116-/- colon carcinoma cell lines, we demonstrate here that CP-31398 induces apoptosis in a dose-, time-, and p53-dependent manner. CP-31398 dramatically elevated p53 and p21(Waf1) protein levels in HCT116+/+, while a smaller p53-independent p21(Waf1) induction by CP-31398 in HCT116-/- cells was also observed. Moreover, we also found that CP-31398 increased Bax expression, altered mitochondrial membrane potential causing the release of cytochrome c, and induced the cleavage of caspases-9 and -3. Taken together, our results indicate that CP-31398 induces p53-dependent apoptosis by activating the Bax/mitochondrial/caspase-9 pathway. Elucidating the mechanism by which CP-31398 induces cell death may establish it as an anticancer agent.
authors.affiliation: Division of Dermatology, Department of Medicine, Vancouver Hospital, Health Sciences Centre, University of British Columbia, Canada.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Luu
authors.forename: Jason
authors.initials: J
authors.lastname: Bush
authors.forename: K-John
authors.initials: KJ
authors.lastname: Cheung
authors.forename: Gang
authors.initials: G
authors.lastname: Li
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects* / Q000235:genetics; D002277:Carcinoma / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects / Q000235:genetics; D002471:Cell Transformation, Neoplastic / Q000187:drug effects / Q000235:genetics; D003110:Colonic Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism; D003574:Cytochrome c Group / Q000187:drug effects / Q000378:metabolism; D005057:Eukaryotic Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008564:Membrane Potentials / Q000187:drug effects / Q000235:genetics; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D009369:Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000187:drug effects / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2; D011743:Pyrimidines / Q000494:pharmacology*; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D051028:bcl-2-Associated X Protein
chemical_list: D000970:Antineoplastic Agents; C494826:BAX protein, human; D003574:Cytochrome c Group; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D011743:Pyrimidines; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; C505407:CASP3 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases; C402665:CP 31398