Protective effects of glycoursodeoxycholic acid in Barrett's esophagus cells.
Barrett's esophagus (BE) is a premalignant condition associated with the development of esophageal adenocarcinoma (EAC). Previous studies have implicated hydrophobic bile acids and gastric acid in BE and EAC pathogenesis. In this study, we tested the hypothesis that DNA damage, cytotoxicity and oxidative stress induced by bile acids and gastric acid can be attenuated by the cytoprotective, hydrophilic bile acid glycoursodeoxycholic acid (GUDCA). Non-dysplastic BE cells were exposed for 10 min to pH 4 and/or bile acid cocktail or to pH 4 and a modified cocktail consisting of a mixture of bile acids and GUDCA. DNA damage was evaluated by the comet assay; cell viability and proliferation were measured by trypan blue staining and the MTS assay; reactive oxygen species (ROS) were measured using hydroethidium staining; oxidative DNA/RNA damage was detected by immunostaining with antibody against 8-OH-dG; thiol levels were measured by 5-chloromethylfluorescein diacetate (CMFDA) staining; and the expression of antioxidant proteins was evaluated by western blotting. DNA damage and oxidative stress were significantly increased, while thiol levels were decreased in BE cells treated with pH 4 and bile acid cocktail compared with cells treated with pH 4 alone or untreated cells. Bile acids and low pH also significantly decreased cell proliferation. Expression of the antioxidant enzymes, MnSOD and CuZnSOD, was elevated in the cells treated with bile acids and low pH. When GUDCA was included in the medium, all these effects of pH 4 and bile acids were markedly reduced. In conclusion, treatment of BE cells with acidified medium and a bile acid cocktail at physiologically relevant concentrations induces DNA damage, cytotoxicity, and ROS. The cytoprotective bile acid, GUDCA, inhibits these deleterious effects by inhibiting oxidative stress.
Goldman
A
A
Department of Cell Biology and Anatomy, the University of Arizona, Tucson, Arizona, USA.
Condon
A
A
Adler
E
E
Minnella
M
M
Bernstein
C
C
Bernstein
H
H
Dvorak
K
K
D000080242:8-Hydroxy-2'-Deoxyguanosine; D000975:Antioxidants / Q000032:analysis; D001471:Barrett Esophagus / Q000473:pathology*; D001647:Bile Acids and Salts / Q000009:adverse effects; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D019610:Cytoprotection / Q000187:drug effects*; D004249:DNA Damage / Q000187:drug effects; D003840:Deoxycholic Acid / Q000009:adverse effects; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000032:analysis; D004947:Esophagus / Q000187:drug effects / Q000473:pathology; D016166:Free Radical Scavengers / Q000032:analysis; D005999:Glycochenodeoxycholic Acid / Q000009:adverse effects; D006000:Glycocholic Acid / Q000009:adverse effects; D006002:Glycodeoxycholic Acid / Q000009:adverse effects; D006801:Humans; D006863:Hydrogen-Ion Concentration; D018384:Oxidative Stress / Q000187:drug effects; D020011:Protective Agents / Q000494:pharmacology*; D012313:RNA / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000032:analysis; D013438:Sulfhydryl Compounds / Q000032:analysis; D013482:Superoxide Dismutase / Q000032:analysis; D013656:Taurocholic Acid / Q000009:adverse effects; D013997:Time Factors; D014580:Ursodeoxycholic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology
D000975:Antioxidants; D001647:Bile Acids and Salts; D016166:Free Radical Scavengers; D020011:Protective Agents; D017382:Reactive Oxygen Species; D013438:Sulfhydryl Compounds; D003840:Deoxycholic Acid; D006002:Glycodeoxycholic Acid; D013656:Taurocholic Acid; D012313:RNA; D005999:Glycochenodeoxycholic Acid; C024033:glycoursodeoxycholic acid; D014580:Ursodeoxycholic Acid; D000080242:8-Hydroxy-2'-Deoxyguanosine; D013482:Superoxide Dismutase; D006000:Glycocholic Acid; D003849:Deoxyguanosine