title: Ethanol promotes cytotoxic effects of tumor necrosis factor-related apoptosis-inducing ligand through induction of reactive oxygen species in prostate cancer cells.
abstract: BACKGROUND
  Effective treatment of prostate cancer (PCa) remains a major challenge due to chemoresistance to drugs including tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Ethanol and ethanol extracts are known apoptosis inducers. However, cytotoxic effects of ethanol on PCa cells are unclear.
  
  
  METHODS
  In this study we utilized PC3 and LNCaP cell culture models. We used immunohistochemical analysis, western blot analysis, reactive oxygen species (ROS) measurement, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) Cell Proliferation Assay, Annexin-V staining and flow cytometry for quantification of apoptosis. In vitro soft agar colony formation and Boyden chamber invasion assays were used. Tumorigenicity was measured in a xenotransplantation mouse model.
  
  
  RESULTS
  Here, we demonstrate that ethanol enhances the apoptosis-inducing potential of TRAIL in androgen-resistant PC3 cells and sensitizes TRAIL-resistant, androgen sensitive LNCaP cells to apoptosis through caspase activation, and a complete cleavage of poly (ADP)-ribose polymerase, which was in association with increased production of ROS. The cytotoxicity of ethanol was suppressed by an antioxidant N-acetyl cystein pretreatment. Furthermore, ethanol in combination with TRAIL increased the expression of cyclin-dependent kinase inhibitor p21 and decreased the levels of Bcl-2 and phosphorylated-AKT. These molecular changes were accompanied by decreased proliferation, anchorage-independent growth and invasive potential of PC3 and LNCaP cells. In vivo studies using a xenotransplantation mouse model with PC3 cells demonstrated significantly increased apoptosis in tumors treated with ethanol and TRAIL in combination.
  
  
  CONCLUSIONS
  Taken together, use of ethanol in combination with TRAIL may be an effective strategy to augment sensitivity to TRAIL-induced apoptosis in PCa cells.
authors.affiliation: Department of Surgery and Urology, University of Vermont, Burlington, VT, USA.
authors.forename: M K
authors.initials: MK
authors.lastname: Plante
authors.forename: W T
authors.initials: WT
authors.lastname: Arscott
authors.forename: J B
authors.initials: JB
authors.lastname: Folsom
authors.forename: S W
authors.initials: SW
authors.lastname: Tighe
authors.forename: R J
authors.initials: RJ
authors.lastname: Dempsey
authors.forename: U V
authors.initials: UV
authors.lastname: Wesley
mesh_terms: D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D000431:Ethanol / Q000494:pharmacology*; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008819:Mice, Nude; D011471:Prostatic Neoplasms / Q000378:metabolism*; D017382:Reactive Oxygen Species; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000494:pharmacology*; D023041:Xenograft Model Antitumor Assays
chemical_list: D017382:Reactive Oxygen Species; D053221:TNF-Related Apoptosis-Inducing Ligand; D000431:Ethanol