title: Anti-apoptotic phenotypes of cholestan-3β,5α,6β-triol-resistant human cholangiocytes: characteristics contributing to the genesis of cholangiocarcinoma.
abstract: The oxysterols cholestan-3β,5α,6β-triol (Triol) and 3-keto-cholest-4-ene (3K4) are increased in Opisthorchis viverrini-associated hamster cholangiocarcinoma and induce DNA damage and apoptosis via a mitochondria-dependent mechanism in MMNK-1 human cholangiocytes. Based on these observations, we hypothesized that chronic exposure of cholangiocytes to these pathogenic oxysterols may allow a growth advantage to a subset of these cells through selection for resistance to apoptosis, thereby contributing to cholangiocarcinogenesis. To test this hypothesis, we cultured MMNK-1 cells long-term in the presence of Triol. Alteration in survival and apoptotic factors of Triol-exposed cells were examined. Cells cultured long-term in the presence of Triol were resistant to H2O2-induced apoptosis, and demonstrated an increase in the phosphorylation of p38-α, CREB, ERK1/2 and c-Jun. Elevations in the ratio of Bcl-2/Bax and in the protein levels of anti-apoptotic factors including cIAP2, clusterin, and survivin were detected. These results show that long-term exposure of MNNK-1 cells to low doses of Triol selects for kinase-signaling molecules which regulate resistance to apoptosis and thereby enhance cell survival. Clonal expansion of such apoptosis-resistant cells may contribute to the genesis of cholangiocarcinoma.
authors: Department of Biochemistry, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand; Liver Fluke and Cholangiocarcinoma Research Center, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand; Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA; Department of Veterans Affairs Medical Center, Seattle, WA, USA.
authors: Apinya
authors: A
authors: Jusakul
authors: Watcharin
authors: W
authors: Loilome
authors: Nisana
authors: N
authors: Namwat
authors: Anchalee
authors: A
authors: Techasen
authors: Rahul
authors: R
authors: Kuver
authors: George N
authors: GN
authors: Ioannou
authors: Christopher
authors: C
authors: Savard
authors: W Geoffrey
authors: WG
authors: Haigh
authors: Puangrat
authors: P
authors: Yongvanit
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects*; D018281:Cholangiocarcinoma / Q000378:metabolism*; D002777:Cholestanols / Q000494:pharmacology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D002777:Cholestanols; C000474:cholestane-3,5,6-triol; D006861:Hydrogen Peroxide; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases
keywords: 3-keto-cholest-4-ene; 3K4; Apoptosis; CCA; CREB; Cholangiocarcinoma; Cholestan-3β,5α,6β-triol; ERK 1/2; MMNK-1 cells; Oxysterols; Triol; cAMP response element-binding; cIAP2; cellular inhibitor of apoptosis 2; cholangiocarcinoma; cholestan-3β,5α,6β-triol; extracellular signal-regulated kinase 1/2; p38 mitogen-activated protein kinase α; p38-α
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