title: Zebrafish reporter lines reveal in vivo signaling pathway activities involved in pancreatic cancer.
abstract: Pancreatic adenocarcinoma, one of the worst malignancies of the exocrine pancreas, is a solid tumor with increasing incidence and mortality in industrialized countries. This condition is usually driven by oncogenic KRAS point mutations and evolves into a highly aggressive metastatic carcinoma due to secondary gene mutations and unbalanced expression of genes involved in the specific signaling pathways. To examine in vivo the effects of KRAS(G12D) during pancreatic cancer progression and time correlation with cancer signaling pathway activities, we have generated a zebrafish model of pancreatic adenocarcinoma in which eGFP-KRAS(G12D) expression was specifically driven to the pancreatic tissue by using the GAL4/UAS conditional expression system. Outcrossing the inducible oncogenic KRAS(G12D) line with transgenic zebrafish reporters, harboring specific signaling responsive elements of transcriptional effectors, we were able to follow TGFβ, Notch, Bmp and Shh activities during tumor development. Zebrafish transgenic lines expressing eGFP-KRAS(G12D) showed normal exocrine pancreas development until 3 weeks post fertilization (wpf). From 4 to 24 wpf we observed several degrees of acinar lesions, characterized by an increase in mesenchymal cells and mixed acinar/ductal features, followed by progressive bowel and liver infiltrations and, finally, highly aggressive carcinoma. Moreover, live imaging analysis of the exocrine pancreatic tissue revealed an increasing number of KRAS-positive cells and progressive activation of TGFβ and Notch pathways. Increase in TGFβ, following KRAS(G12D) activation, was confirmed in a concomitant model of medulloblastoma (MDB). Notch and Shh signaling activities during tumor onset were different between MDB and pancreatic adenocarcinoma, indicating a tissue-specific regulation of cell signaling pathways. Moreover, our results show that a living model of pancreatic adenocarcinoma joined with cell signaling reporters is a suitable tool for describing in vivo the signaling cascades and molecular mechanisms involved in tumor development and a potential platform to screen for novel oncostatic drugs.
authors.affiliation: Department of Biology, University of Padua, 35131 Padua, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Schiavone
authors.affiliation: Department of Molecular Medicine, University of Padua, 35131 Padua, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Rampazzo
authors.affiliation: Department of Biology, University of Padua, 35131 Padua, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Casari
authors.affiliation: Department of Molecular Medicine, University of Padua, 35131 Padua, Italy.
authors.forename: Giusy
authors.initials: G
authors.lastname: Battilana
authors.affiliation: Department of Woman and Child Health, University of Padua, 35131 Padua, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Persano
authors.affiliation: Department of Molecular Medicine, University of Padua, 35131 Padua, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Moro
authors.affiliation: Department of Surgery and The McKusick-Nathans Institute of Genetic Medicine Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Shu
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Surgery and The McKusick-Nathans Institute of Genetic Medicine Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Steve D
authors.initials: SD
authors.lastname: Leach
authors.affiliation: Department of Biology, University of Padua, 35131 Padua, Italy.
authors.forename: Natascia
authors.initials: N
authors.lastname: Tiso
authors.affiliation: Department of Biology, University of Padua, 35131 Padua, Italy. francesco.argenton@unipd.it.
authors.forename: Francesco
authors.initials: F
authors.lastname: Argenton
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics / Q000473:pathology; D000818:Animals; D030801:Animals, Genetically Modified; D017209:Apoptosis / Q000235:genetics; D015415:Biomarkers / Q000378:metabolism; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic / Q000235:genetics / Q000473:pathology; D004195:Disease Models, Animal; D018450:Disease Progression; D058750:Epithelial-Mesenchymal Transition / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000378:metabolism; D053208:Kaplan-Meier Estimate; D008527:Medulloblastoma / Q000473:pathology; D050505:Mutant Proteins / Q000378:metabolism; D009928:Organ Specificity; D010190:Pancreatic Neoplasms / Q000235:genetics* / Q000473:pathology*; D011401:Promoter Regions, Genetic / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras); D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics; D015027:Zebrafish / Q000235:genetics*; D029961:Zebrafish Proteins / Q000378:metabolism
chemical_list: D015415:Biomarkers; D050505:Mutant Proteins; D014157:Transcription Factors; D029961:Zebrafish Proteins; C485184:enhanced green fluorescent protein; C062602:transcription factor PTF1; D049452:Green Fluorescent Proteins; C000589775:Kras protein, zebrafish; D016283:Proto-Oncogene Proteins p21(ras)
keywords: KRAS; Medulloblastoma; Notch; Pancreatic adenocarcinoma; Reporters; Shh; TGFβ; Zebrafish