Participation of Omi Htra2 serine-protease activity in the apoptosis induced by cisplatin on SW480 colon cancer cells.
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.
Pruefer
F G
FG
Molecular Biology Laboratory, Subdireccion de Investigacion Básica, Instituto Nacional de Cancerología, Mexico City, Mexico.
Lizarraga
F
F
Maldonado
V
V
Melendez-Zajgla
J
J
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
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