title: Nicotine promotes initiation and progression of KRAS-induced pancreatic cancer via Gata6-dependent dedifferentiation of acinar cells in mice.
abstract: OBJECTIVE
  Although smoking is a leading risk factor for pancreatic ductal adenocarcinoma (PDAC), little is known about the mechanisms by which smoking promotes initiation or progression of PDAC.
  
  
  METHODS
  We studied the effects of nicotine administration on pancreatic cancer development in Kras(+/LSLG12Vgeo);Elas-tTA/tetO-Cre (Ela-KRAS) mice, Kras(+/LSLG12D);Trp53+/LSLR172H;Pdx-1-Cre (KPC) mice (which express constitutively active forms of KRAS), and C57/B6 mice. Mice were given nicotine for up to 86 weeks to produce blood levels comparable with those of intermediate smokers. Pancreatic tissues were collected and analyzed by immunohistochemistry and reverse transcriptase polymerase chain reaction; cells were isolated and assayed for colony and sphere formation and gene expression. The effects of nicotine were also evaluated in primary pancreatic acinar cells isolated from wild-type, nAChR7a(-/-), Trp53(-/-), and Gata6(-/-);Trp53(-/-) mice. We also analyzed primary PDAC cells that overexpressed GATA6 from lentiviral expression vectors.
  
  
  RESULTS
  Administration of nicotine accelerated transformation of pancreatic cells and tumor formation in Ela-KRAS and KPC mice. Nicotine induced dedifferentiation of acinar cells by activating AKT-ERK-MYC signaling; this led to inhibition of Gata6 promoter activity, loss of GATA6 protein, and subsequent loss of acinar differentiation and hyperactivation of oncogenic KRAS. Nicotine also promoted aggressiveness of established tumors as well as the epithelial-mesenchymal transition, increasing numbers of circulating cancer cells and their dissemination to the liver, compared with mice not exposed to nicotine. Nicotine induced pancreatic cells to acquire gene expression patterns and functional characteristics of cancer stem cells. These effects were markedly attenuated in K-Ras(+/LSL-G12D);Trp53(+/LSLR172H);Pdx-1-Cre mice given metformin. Metformin prevented nicotine-induced pancreatic carcinogenesis and tumor growth by up-regulating GATA6 and promoting differentiation toward an acinar cell program.
  
  
  CONCLUSIONS
  In mice, nicotine promotes pancreatic carcinogenesis and tumor development via down-regulation of Gata6 to induce acinar cell dedifferentiation.
authors.affiliation: Stem Cells and Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.
authors.forename: Patrick C
authors.initials: PC
authors.lastname: Hermann
authors.affiliation: Stem Cells and Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.
authors.forename: Patricia
authors.initials: P
authors.lastname: Sancho
authors.affiliation: Comparative Pathology Core Unit, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Cañamero
authors.affiliation: Epithelial Carcinogenesis Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.
authors.forename: Paola
authors.initials: P
authors.lastname: Martinelli
authors.affiliation: Epithelial Carcinogenesis Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.
authors.forename: Francesc
authors.initials: F
authors.lastname: Madriles
authors.affiliation: Department of Gastroenterology, Endocrinology, Metabolism and Infectiology, University of Marburg, Marburg, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Michl
authors.affiliation: Department of Gastroenterology, Endocrinology, Metabolism and Infectiology, University of Marburg, Marburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Gress
authors.affiliation: Instituto Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.
authors.forename: Ricardo
authors.initials: R
authors.lastname: de Pascual
authors.affiliation: Instituto Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Gandia
authors.affiliation: Experimental Oncology Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Guerra
authors.affiliation: Experimental Oncology Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.
authors.forename: Mariano
authors.initials: M
authors.lastname: Barbacid
authors.affiliation: Department of Internal Medicine I, Ulm University, Ulm, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Wagner
authors.affiliation: Stem Cells and Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.
authors.forename: Catarina R
authors.initials: CR
authors.lastname: Vieira
authors.affiliation: Stem Cells and Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Aicher
authors.affiliation: Epithelial Carcinogenesis Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.
authors.forename: Francisco X
authors.initials: FX
authors.lastname: Real
authors.affiliation: Stem Cells and Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain. Electronic address: bruno.sainz@uam.es.
authors.forename: Bruno
authors.initials: B
authors.lastname: Sainz
authors.affiliation: Stem Cells and Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain; Centre for Stem Cells in Cancer & Ageing, Barts Cancer Institute, Queen Mary University of London, UK. Electronic address: c.heeschen@qmul.ac.uk.
authors.forename: Christopher
authors.initials: C
authors.lastname: Heeschen
mesh_terms: D061354:Acinar Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D000818:Animals; D021441:Carcinoma, Pancreatic Ductal / Q000139:chemically induced* / Q000235:genetics / Q000378:metabolism / Q000517:prevention & control / Q000556:secondary; D054337:Cell Dedifferentiation / Q000187:drug effects*; D045744:Cell Line, Tumor; D002471:Cell Transformation, Neoplastic / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D050993:GATA6 Transcription Factor / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism / Q000556:secondary; D008687:Metformin / Q000494:pharmacology; D057507:Mice, 129 Strain; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008819:Mice, Nude; D009154:Mutation; D009360:Neoplastic Cells, Circulating / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D009538:Nicotine / Q000633:toxicity*; D018722:Nicotinic Agonists / Q000633:toxicity*; D010179:Pancreas / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000139:chemically induced* / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism; D016283:Proto-Oncogene Proteins p21(ras) / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D014162:Transfection; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism; D064569:alpha7 Nicotinic Acetylcholine Receptor / Q000235:genetics / Q000378:metabolism
chemical_list: C579166:Chrna7 protein, mouse; D050993:GATA6 Transcription Factor; C494760:Gata6 protein, mouse; C489428:Myc protein, mouse; D018722:Nicotinic Agonists; D016271:Proto-Oncogene Proteins c-myc; D016159:Tumor Suppressor Protein p53; D064569:alpha7 Nicotinic Acetylcholine Receptor; D009538:Nicotine; D008687:Metformin; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; C495971:Hras protein, mouse; D016283:Proto-Oncogene Proteins p21(ras)
keywords: Metastasis; Mouse Model; Pancreas; Progenitor Cells