title: Participation of Omi Htra2 serine-protease activity in the apoptosis induced by cisplatin on SW480 colon cancer cells.
abstract: Apoptosis is triggered by two interconnected pathways, extrinsic and intrinsic. The intrinsic pathway is activated by genomic stress promoting mitochondrial release of apoptotic proteins. One of these proteins is Omi/Htra2, a serine protease which inactivates Inhibitor of Apoptosis Proteins (IAPs). In the present work, we assessed the participation of Omi/Htra2 in the cell death induced by the chemotherapeutic drugs 5-fluorouracil (5-FU) and cisplatin (CDDP) in SW480 colon cancer cells. CDDP and 5-FU induced apoptosis mediated by the intrinsic pathway in colon cancer cells, as demonstrated by morphological analyses, mitochondrial cytochrome c release and cleavage of caspase 3. Omi/Htra2 was also released from mitochondria of cells exposed to these drugs, as demonstrated by immunofluorescence and western blot assays of subcellular fractions. Exposure of cells to the Omi/Htra2 serine protease inhibitor UCF-101 prevented death p<0.0001 and partially suppressed reproductive cell death of cells exposed to cisplatin p<0.05, but not to 5-FU p=0.49. From these experiments we show that Omi/Htra2 serine protease activity participates in the cell death induced by CDDP but not of 5-FU in colon cancer cells.
authors.affiliation: Molecular Biology Laboratory, Subdireccion de Investigacion Básica, Instituto Nacional de Cancerología, Mexico City, Mexico.
authors.forename: F G
authors.initials: FG
authors.lastname: Pruefer
authors.forename: F
authors.initials: F
authors.lastname: Lizarraga
authors.forename: V
authors.initials: V
authors.lastname: Maldonado
authors.forename: J
authors.initials: J
authors.lastname: Melendez-Zajgla
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology*; D003110:Colonic Neoplasms / Q000201:enzymology*; D005472:Fluorouracil / Q000494:pharmacology; D000074923:High-Temperature Requirement A Serine Peptidase 2; D006801:Humans; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology; D024101:Mitochondrial Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011744:Pyrimidinones / Q000494:pharmacology; D012697:Serine Endopeptidases / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D013871:Thiones / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; D024101:Mitochondrial Proteins; D011744:Pyrimidinones; D015842:Serine Proteinase Inhibitors; D013871:Thiones; C501517:UCF 101; D012697:Serine Endopeptidases; C000615914:HTRA2 protein, human; D000074923:High-Temperature Requirement A Serine Peptidase 2; D002945:Cisplatin; D005472:Fluorouracil