title: Curcumin-mediated regulation of Notch1/hairy and enhancer of split-1/survivin: molecular targeting in cholangiocarcinoma.
abstract: BACKGROUND
  Cholangiocarcinoma (CCA) is highly malignant and characterized by poor prognosis with chemotherapeutic resistance. Therefore, continued development of novel, effective approaches are needed. Notch expression is markedly upregulated in CCA, but the utility of Notch1 inhibition is not defined. Based on recent findings, we hypothesized that curcumin, a polyphenolic phytochemical, suppresses CCA growth in vitro via inhibition of Notch1 signaling.
  
  
  METHODS
  Established CCA cell lines CCLP-1 and SG-231 were treated with varying concentrations of curcumin (0-20 μM). Viability was assessed through 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide and clonogenic assays. Evaluation of apoptosis was determined via Western analysis for apoptotic markers and Caspase-Glo 3/7 assay. Cell lysates were further analyzed via Western blotting for Notch1/HES-1/survivin pathway expression, cell cycle progression, and survival.
  
  
  RESULTS
  Curcumin-treated CCA cells exhibited reduced viability compared with control treatment. Statistically significant reductions in cell viability were observed with curcumin treatment at concentrations of 7.5, 10, and 15 μM by approximately 10%, 48%, and 56% for CCLP-1 and 13%, 25%, and 50% for SG-231, respectively. On Western analysis, concentrations of ≥10 μM showed reductions in Notch1, HES-1, and survivin. Apoptosis was evidenced by an increase in expression of cleaved poly [ADP] ribose polymerase and an increase in caspase activity. Cyclin D1 (cell cycle progression) expression levels were also reduced with treatment.
  
  
  CONCLUSIONS
  Curcumin effectively induces CCA (CCLP-1 and SG-231) growth suppression and apoptosis at relatively low treatment concentrations when compared with the previous research. A concomitant reduction of Notch1, HES-1, and survivin expression in CCA cell lines provides novel evidence for a potential antitumorigenic mechanism-of-action. To our knowledge, this is the first report showing reduction in HES-1 expression via protein analysis after treatment with curcumin. Such findings merit further investigation of curcumin-mediated inhibition of Notch signaling in CCA either alone or in combination with chemotherapeutic agents.
authors.affiliation: Division of Surgical Oncology, Department of Surgery, MCW Cancer Center, Translational and Biomedical Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin.
authors.forename: Steven
authors.initials: S
authors.lastname: Koprowski
authors.affiliation: Division of Surgical Oncology, Department of Surgery, MCW Cancer Center, Translational and Biomedical Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin.
authors.forename: Kevin
authors.initials: K
authors.lastname: Sokolowski
authors.affiliation: Division of Surgical Oncology, Department of Surgery, MCW Cancer Center, Translational and Biomedical Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin.
authors.forename: Selvi
authors.initials: S
authors.lastname: Kunnimalaiyaan
authors.affiliation: Division of Surgical Oncology, Department of Surgery, MCW Cancer Center, Translational and Biomedical Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin. Electronic address: tcgamblin@mcw.edu.
authors.forename: T Clark
authors.initials: TC
authors.lastname: Gamblin
authors.affiliation: Division of Surgical Oncology, Department of Surgery, MCW Cancer Center, Translational and Biomedical Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin. Electronic address: mkunnima@mcw.edu.
authors.forename: Muthusamy
authors.initials: M
authors.lastname: Kunnimalaiyaan
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism; D001650:Bile Duct Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D018281:Cholangiocarcinoma / Q000188:drug therapy* / Q000378:metabolism; D030024:Curcuma; D003474:Curcumin / Q000494:pharmacology / Q000627:therapeutic use*; D004354:Drug Screening Assays, Antitumor; D018398:Homeodomain Proteins / Q000378:metabolism; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins / Q000378:metabolism; D008517:Phytotherapy; D051881:Receptor, Notch1 / Q000378:metabolism; D000077022:Survivin; D000072056:Transcription Factor HES-1
chemical_list: D000970:Antineoplastic Agents; D051792:Basic Helix-Loop-Helix Proteins; D003474:Curcumin; D018398:Homeodomain Proteins; D051034:Inhibitor of Apoptosis Proteins; D051881:Receptor, Notch1; D000077022:Survivin; D000072056:Transcription Factor HES-1; C107489:BIRC5 protein, human; C497761:NOTCH1 protein, human; C078493:HES1 protein, human
keywords: Apoptosis; Cholangiocarcinoma; Curcumin; Notch signaling; Survivin