title: Loss of Stromal IMP1 Promotes a Tumorigenic Microenvironment in the Colon.
abstract: The colon tumor microenvironment is becoming increasingly recognized as a complex but central player in the development of many cancers. Previously, we identified an oncogenic role for the mRNA-binding protein IMP1 (IGF2BP1) in the epithelium during colon tumorigenesis. In the current study, we reveal the contribution of stromal IMP1 in the context of colitis-associated colon tumorigenesis. Interestingly, stromal deletion of Imp1 (Dermo1Cre;Imp1(LoxP/LoxP), or Imp1(ΔMes)) in the azoxymethane/dextran sodium sulfate (AOM/DSS) model of colitis-associated cancer resulted in increased tumor numbers of larger size and more advanced histologic grade than controls. In addition, Imp1(ΔMes) mice exhibited a global increase in protumorigenic microenvironment factors, including enhanced inflammation and stromal components. Evaluation of purified mesenchyme from AOM/DSS-treated Imp1(ΔMes) mice demonstrated an increase in hepatocyte growth factor (HGF), which has not been associated with regulation via IMP1. Genetic knockdown of Imp1 in human primary fibroblasts confirmed an increase in HGF with Imp1 loss, demonstrating a specific, cell-autonomous role for Imp1 loss to increase HGF expression. Taken together, these data demonstrate a novel tumor-suppressive role for IMP1 in colon stromal cells and underscore an exquisite, context-specific function for mRNA-binding proteins, such as IMP1, in disease states.
  
  
  CONCLUSIONS
  The tumor-suppressive role of stromal IMP1 and its ability to modulate protumorigenic factors suggest that IMP1 status is important for the initiation and growth of epithelial tumors.
authors.affiliation: Division of Gastroenterology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania. Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.
authors.forename: Kathryn E
authors.initials: KE
authors.lastname: Hamilton
authors.affiliation: Division of Gastroenterology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania. Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.
authors.forename: Priya
authors.initials: P
authors.lastname: Chatterji
authors.affiliation: Division of Gastroenterology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania. Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.
authors.forename: Emma T
authors.initials: ET
authors.lastname: Lundsmith
authors.affiliation: Division of Gastroenterology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania. Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.
authors.forename: Sarah F
authors.initials: SF
authors.lastname: Andres
authors.affiliation: Division of Gastroenterology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania. Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.
authors.forename: Veronique
authors.initials: V
authors.lastname: Giroux
authors.affiliation: Division of Gastroenterology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania. Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.
authors.forename: Philip D
authors.initials: PD
authors.lastname: Hicks
authors.affiliation: Department of Pediatrics, Pennsylvaia State University, College of Medicine, Hershey, Pennsylvania. Division of Pediatric Hematology/Oncology, Pennsylvaia State University, College of Medicine, Hershey, Pennsylvania. Department of Biomedical Engineering, University of Minnesota Twin Cities, Minneapolis, Minnesota.
authors.forename: Felicite K
authors.initials: FK
authors.lastname: Noubissi
authors.affiliation: Department of Pediatrics, Pennsylvaia State University, College of Medicine, Hershey, Pennsylvania. Division of Pediatric Hematology/Oncology, Pennsylvaia State University, College of Medicine, Hershey, Pennsylvania.
authors.forename: Vladimir S
authors.initials: VS
authors.lastname: Spiegelman
authors.affiliation: Division of Gastroenterology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania. Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania. Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania. Abramson Cancer Center, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania. anil2@mail.med.upenn.edu.
authors.forename: Anil K
authors.initials: AK
authors.lastname: Rustgi
mesh_terms: D000818:Animals; D003110:Colonic Neoplasms / Q000378:metabolism / Q000473:pathology; D017353:Gene Deletion; D017228:Hepatocyte Growth Factor / Q000378:metabolism; D006801:Humans; D008648:Mesoderm / Q000378:metabolism; D051379:Mice; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D017154:Stromal Cells / Q000378:metabolism; D059016:Tumor Microenvironment
chemical_list: C406144:IGF2BP1 protein, human; D016601:RNA-Binding Proteins; D017228:Hepatocyte Growth Factor