title: Identification and manipulation of biliary metaplasia in pancreatic tumors.
abstract: OBJECTIVE
  Metaplasias often have characteristics of developmentally related tissues. Pancreatic metaplastic ducts are usually associated with pancreatitis and pancreatic ductal adenocarcinoma. The tuft cell is a chemosensory cell that responds to signals in the extracellular environment via effector molecules. Commonly found in the biliary tract, tuft cells are absent from normal murine pancreas. Using the aberrant appearance of tuft cells as an indicator, we tested if pancreatic metaplasia represents transdifferentiation to a biliary phenotype and what effect this has on pancreatic tumorigenesis.
  
  
  METHODS
  We analyzed pancreatic tissue and tumors that developed in mice that express an activated form of Kras (Kras(LSL-G12D/+);Ptf1a(Cre/+) mice). Normal bile duct, pancreatic duct, and tumor-associated metaplasias from the mice were analyzed for tuft cell and biliary progenitor markers, including SOX17, a transcription factor that regulates biliary development. We also analyzed pancreatic tissues from mice expressing transgenic SOX17 alone (ROSA(tTa/+);Ptf1(CreERTM/+);tetO-SOX17) or along with activated Kras (ROSAtT(a/+);Ptf1a(CreERTM/+);tetO-SOX17;Kras(LSL-G12D;+)).
  
  
  RESULTS
  Tuft cells were frequently found in areas of pancreatic metaplasia, decreased throughout tumor progression, and absent from invasive tumors. Analysis of the pancreatobiliary ductal systems of mice revealed tuft cells in the biliary tract but not the normal pancreatic duct. Analysis for biliary markers revealed expression of SOX17 in pancreatic metaplasia and tumors. Pancreas-specific overexpression of SOX17 led to ductal metaplasia along with inflammation and collagen deposition. Mice that overexpressed SOX17 along with Kras(G12D) had a greater degree of transformed tissue compared with mice expressing only Kras(G12D). Immunofluorescence analysis of human pancreatic tissue arrays revealed the presence of tuft cells in metaplasia and early-stage tumors, along with SOX17 expression, consistent with a biliary phenotype.
  
  
  CONCLUSIONS
  Expression of Kras(G12D) and SOX17 in mice induces development of metaplasias with a biliary phenotype containing tuft cells. Tuft cells express a number of tumorigenic factors that can alter the microenvironment. Expression of SOX17 induces pancreatitis and promotes Kras(G12D)-induced tumorigenesis in mice.
authors.affiliation: Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York; Department of Cancer Biology, Mayo Clinic, Jacksonville, Florida.
authors.forename: Kathleen E
authors.initials: KE
authors.lastname: Delgiorno
authors.affiliation: Department of Cancer Biology, Mayo Clinic, Jacksonville, Florida; Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York.
authors.forename: Jason C
authors.initials: JC
authors.lastname: Hall
authors.affiliation: Department of Cancer Biology, Mayo Clinic, Jacksonville, Florida.
authors.forename: Kenneth K
authors.initials: KK
authors.lastname: Takeuchi
authors.affiliation: Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee.
authors.forename: Fong Cheng
authors.initials: FC
authors.lastname: Pan
authors.affiliation: Department of Cancer Biology, Mayo Clinic, Jacksonville, Florida; Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Halbrook
authors.affiliation: Department of Pathology, Vanderbilt University Medical Center, Nashville, Tennessee.
authors.forename: M Kay
authors.initials: MK
authors.lastname: Washington
authors.affiliation: Departments of Medicine and Pathology, Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, New York.
authors.forename: Kenneth P
authors.initials: KP
authors.lastname: Olive
authors.affiliation: Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan.
authors.forename: Jason R
authors.initials: JR
authors.lastname: Spence
authors.affiliation: Department of Pathology, University Hospital Tubingen, Tubingen, Germany.
authors.forename: Bence
authors.initials: B
authors.lastname: Sipos
authors.affiliation: Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee.
authors.forename: Christopher V E
authors.initials: CV
authors.lastname: Wright
authors.affiliation: Department of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.
authors.forename: James M
authors.initials: JM
authors.lastname: Wells
authors.affiliation: Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York; Department of Cancer Biology, Mayo Clinic, Jacksonville, Florida. Electronic address: crawford.howard@mayo.edu.
authors.forename: Howard C
authors.initials: HC
authors.lastname: Crawford
mesh_terms: D000818:Animals; D001652:Bile Ducts / Q000166:cytology* / Q000378:metabolism; D021441:Carcinoma, Pancreatic Ductal / Q000150:complications / Q000378:metabolism / Q000473:pathology*; D002471:Cell Transformation, Neoplastic / Q000378:metabolism / Q000473:pathology*; D024002:HMGB Proteins / Q000378:metabolism*; D006801:Humans; D008679:Metaplasia / Q000150:complications / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008822:Mice, Transgenic; D010183:Pancreatic Ducts / Q000166:cytology / Q000378:metabolism / Q000473:pathology*; D010190:Pancreatic Neoplasms / Q000150:complications / Q000378:metabolism / Q000473:pathology*; D010195:Pancreatitis / Q000378:metabolism; D011230:Precancerous Conditions / Q000378:metabolism / Q000473:pathology*; D016283:Proto-Oncogene Proteins p21(ras) / Q000378:metabolism; D055760:SOXF Transcription Factors / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D024002:HMGB Proteins; D055760:SOXF Transcription Factors; C511606:Sox17 protein, mouse; C495971:Hras protein, mouse; D016283:Proto-Oncogene Proteins p21(ras)
keywords: 4′,6-diamidino-2-phenylindole; ADM; COX; DAPI; DCLK1; EGFR; IF; IHC; Mouse Model; PBG; PDA; PDG; PanIN; Pancreatic Cancer; Pathogenesis; Signal Transduction; YFP; acinar-to-ductal metaplasia; cyclooxygenase; doublecortin-like kinase 1; epidermal growth factor receptor; immunofluorescence; immunohistochemistry; mPanIN; murine pancreatic intraepithelial neoplasia; pancreatic duct gland; pancreatic ductal adenocarcinoma; pancreatic intraepithelial neoplasia; peribiliary gland; yellow fluorescent protein