title: Curcumin-induced apoptosis in PC3 prostate carcinoma cells is caspase-independent and involves cellular ceramide accumulation and damage to mitochondria.
abstract: Curcumin, the principal curcuminoid of tumeric, has potent anticancer activity. To determine the mechanism of curcumin-induced cytotoxicity in prostate cancer cells, we exposed PC3 prostate carcinoma cells to 25 to 100 microM curcumin for 24 to 72 h. Curcumin treatment of PC3 cells caused time- and dose-dependent induction of apoptosis and depletion of cellular reduced glutathione (GSH). Exogenous GSH and its precursor N-acetyl-cysteine, but not ascorbic acid (AA) or ebselen, decreased curcumin accumulation in PC3 cells and also prevented curcumin-induced DNA fragmentation. The failure of AA and ebselen to protect PC3 cells from curcumin-induced apoptosis argued against the involvement of reactive oxygen species; rather, GSH-mediated inhibition of curcumin-induced cytotoxicity was due to reduced curcumin accumulation in PC3 cells. Curcumin-treated PC3 cells showed apoptosis-inducing cellular ceramide accumulation and activation of p38 mitogen-activated protein kinase (MAPK) and c-jun N-terminal kinase (JNK). Caspase-3, caspase-8, and caspase-9 were activated, and cytochrome c and apoptosis-inducing factor (AIF) were released from mitochondria following curcumin treatment. Interestingly, curcumin-induced apoptosis was not prevented by p38 MAPK, JNK, or caspase inhibition. We conclude that curcumin-induced cytotoxicity was due to cellular ceramide accumulation and damage to mitochondria that resulted in apoptosis mediated by AIF and other caspase-independent processes.
authors.affiliation: Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Ashley L
authors.initials: AL
authors.lastname: Hilchie
authors.forename: Suzanne J
authors.initials: SJ
authors.lastname: Furlong
authors.forename: Kimberly
authors.initials: K
authors.lastname: Sutton
authors.forename: Angela
authors.initials: A
authors.lastname: Richardson
authors.forename: Matthew R J
authors.initials: MR
authors.lastname: Robichaud
authors.forename: Carman A
authors.initials: CA
authors.lastname: Giacomantonio
authors.forename: Neale D
authors.initials: ND
authors.lastname: Ridgway
authors.forename: David W
authors.initials: DW
authors.lastname: Hoskin
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D020169:Caspases / Q000502:physiology*; D045744:Cell Line, Tumor; D002518:Ceramides / Q000378:metabolism*; D003474:Curcumin / Q000494:pharmacology*; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D008297:Male; D008928:Mitochondria / Q000502:physiology*; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D017382:Reactive Oxygen Species / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D002518:Ceramides; D017382:Reactive Oxygen Species; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D020169:Caspases; D005978:Glutathione; D003474:Curcumin