title: Murine portal vein catheterization to analyze liver-directed therapies.
abstract: BACKGROUND
  Small interfering RNA (siRNA) provides a highly selective method to target mutated pathways; however, its use is complicated by specific delivery to tumor cells. The aims of the present study were to develop a novel murine model of portal vein catheterization for the chronic delivery of therapeutic agents to liver metastases, determine the benefits of local delivery of siRNA to liver metastases, and determine the utility of epithelial cell adhesion molecule (EpCAM) as a selective target for siRNA delivery to colorectal cancer (CRC) metastases.
  
  
  METHODS
  First, portal vein catheterization was performed through a midline laparotomy in 2 mo-old Balb/C mice. Second, the portal venous flow distribution and catheter patency were evaluated using fluorescent-labeled microspheres. Metastatic studies were performed by splenic injection of CT26 murine colon cancer cells. Uptake of DY-547-labeled siRNA was assessed by IVIS imaging, with delivery to the metastases confirmed using fluorescent microscopy. Finally, EpCAM expression was evaluated using immunohistochemical staining of human tissue microarrays.
  
  
  RESULTS
  Successful portal vein catheterization was confirmed by saline injection and ultrasound. Fluorescent imaging of microspheres confirmed excellent distribution and catheter patency. Portal venous injection of DY547-labeled siRNA demonstrated a high level of fluorescence throughout the liver, with siRNA also identified within the liver metastases. Also, all primary CRCs and liver metastases stained strongly for EpCAM, with no expression in normal hepatocytes.
  
  
  CONCLUSIONS
  Liver-directed therapy can provide the selective delivery of siRNA to CRC metastases. EpCAM expression in CRC, but not normal liver, could further selectively target hepatic metastases of epithelial origin.
authors.affiliation: Department of Surgery, University of Kentucky, Lexington, Kentucky; Markey Cancer Center, University of Kentucky, Lexington, Kentucky.
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Valentino
authors.forename: Piotr G
authors.initials: PG
authors.lastname: Rychahou
authors.forename: W Conan
authors.initials: WC
authors.lastname: Mustain
authors.forename: Victoria A
authors.initials: VA
authors.lastname: Elliott
authors.forename: B Mark
authors.initials: BM
authors.lastname: Evers
mesh_terms: D000818:Animals; D000951:Antigens, Neoplasm / Q000235:genetics*; D002405:Catheterization, Central Venous / Q000379:methods*; D015815:Cell Adhesion Molecules / Q000235:genetics*; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000556:secondary / Q000628:therapy*; D004195:Disease Models, Animal; D000071858:Epithelial Cell Adhesion Molecule; D015316:Genetic Therapy / Q000379:methods*; D008099:Liver / Q000098:blood supply / Q000473:pathology; D008114:Liver Neoplasms, Experimental / Q000556:secondary / Q000628:therapy*; D051379:Mice; D008807:Mice, Inbred BALB C; D008863:Microspheres; D009368:Neoplasm Transplantation; D011137:Polystyrenes / Q000493:pharmacokinetics; D011169:Portal Vein; D034741:RNA, Small Interfering / Q000494:pharmacology
chemical_list: D000951:Antigens, Neoplasm; D015815:Cell Adhesion Molecules; D000071858:Epithelial Cell Adhesion Molecule; D011137:Polystyrenes; D034741:RNA, Small Interfering
keywords: Animal model; Catheterization; Colorectal cancer; Liver metastasis; Portal vein; siRNA
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