title: 12-Lipoxygenase inhibition induced apoptosis in human gastric cancer cells.
abstract: Arachidonic acid release from membrane phospholipids is essential for tumour cell proliferation. Lipoxygenases constitute a pathway for arachidonate metabolism. The present study investigated the expression of 12-lipoxygenase and its effect on cell proliferation as well as survival in two human gastric cancer cell lines (AGS and MKN-28). RT-PCR and western blots, respectively, showed 12-LOX mRNA and protein expression in both AGS and MKN-28 cell lines. Treatment with a 12-LOX inhibitor, baicalein, significantly inhibited cancer cell proliferation, but a metabolite of 12-LOX activity, 12 hydroxyeicosatetraenoic acid (12-HETE) reversed baicalein-induced growth inhibition. Furthermore, the blockade of the 12-LOX pathway through a 12-LOX inhibitor and antisense induced apoptosis of gastric cancer cell lines. The biochemical characteristics of apoptosis were p53-independent combined with a decrease in bcl-2 expression. Caspase-7 was proteolytically activated and responsible for the apoptosis execution.
authors.affiliation: Department of Medicine, Department of Pharmacology and Institute of Molecular Biology, University of Hong Kong, Hong Kong, China. bcywong@hku.hk
authors.forename: B C
authors.initials: BC
authors.lastname: Wong
authors.forename: W P
authors.initials: WP
authors.lastname: Wang
authors.forename: C H
authors.initials: CH
authors.lastname: Cho
authors.forename: X M
authors.initials: XM
authors.lastname: Fan
authors.forename: M C
authors.initials: MC
authors.lastname: Lin
authors.forename: H F
authors.initials: HF
authors.lastname: Kung
authors.forename: S K
authors.initials: SK
authors.lastname: Lam
mesh_terms: D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D001092:Arachidonate 12-Lipoxygenase / Q000096:biosynthesis / Q000235:genetics; D001792:Blood Platelets / Q000201:enzymology; D015153:Blotting, Western; D053148:Caspase 3; D053179:Caspase 7; D020169:Caspases / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D004347:Drug Interactions; D044950:Flavanones; D005419:Flavonoids / Q000494:pharmacology*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006131:Growth Inhibitors / Q000494:pharmacology; D006801:Humans; D016859:Lipoxygenase Inhibitors / Q000494:pharmacology*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D013274:Stomach Neoplasms / Q000201:enzymology / Q000473:pathology*; D014407:Tumor Cells, Cultured
chemical_list: D044950:Flavanones; D005419:Flavonoids; D006131:Growth Inhibitors; D016859:Lipoxygenase Inhibitors; D012333:RNA, Messenger; C006680:baicalein; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D001092:Arachidonate 12-Lipoxygenase; C505407:CASP3 protein, human; C505520:CASP7 protein, human; D053148:Caspase 3; D053179:Caspase 7; D020169:Caspases