title: Specific occlusion of murine and human tumor vasculature by VCAM-1-targeted recombinant fusion proteins.
abstract: BACKGROUND
  The tumor vasculature is increasingly recognized as a target for cancer therapy. We developed and evaluated recombinant fusion proteins targeting the coagulation-inducing protein soluble tissue factor (sTF) to the luminal tumor endothelial antigen vascular cell adhesion molecule 1 (VCAM-1, CD106).
  
  
  METHODS
  We generated fusion proteins consisting of sTF fused to antibody fragments directed against mouse or human VCAM-1 and characterized them in vitro by flow cytometry, surface plasmon resonance, and two-stage coagulation assays. Their therapeutic effects were tested in three human xenograft tumor models: L540rec Hodgkin lymphoma, Colo677 small-cell lung carcinoma, and Colo677/HDMEC small-cell lung carcinoma with human vasculature. Toxicity was analyzed by histologic examination of organs and determination of laboratory blood parameters.
  
  
  RESULTS
  The fusion proteins bound VCAM-1 with nanomolar affinities and had the same coagulation activity as an sTF standard. Xenograft tumor-bearing mice treated with fusion protein (FP) alone or in combination with lipopolysaccharide (FP/L) or doxorubicin (FP/D) exhibited tumor-selective necrosis (L540rec tumors: 74% tumor necrosis [95% confidence interval {CI} = 55% to 93%] with FP/L versus 13% tumor necrosis [95% CI = 4% to 22%] with vehicle; Colo677 tumors: 26% [95% CI = 16% to 36%] with FP versus 8% [95% CI = 2% to 14%] with vehicle); tumor growth delay (Colo677/HDMEC: mean tumor weights after 3 days = 42 mg in FP-treated mice versus 71 mg in vehicle-treated mice, difference = 29 mg, 95% CI = 8 to 100, Mann-Whitney P = .008); and some tumor regressions (one of seven FP-treated Colo677 tumor-bearing mice and two of seven FP/D-treated mice). The fusion protein was well tolerated.
  
  
  CONCLUSIONS
  Recombinant tissue factor-based fusion proteins directed against an intraluminal tumor endothelial cell marker induce tumor-selective intravascular coagulation, tumor tissue necrosis, and tumor growth delay.
authors.affiliation: Department of Internal Medicine I, University Hospital Cologne, Cologne, Germany.
authors.forename: Ariane
authors.initials: A
authors.lastname: Dienst
authors.forename: Andrea
authors.initials: A
authors.lastname: Grunow
authors.forename: Maike
authors.initials: M
authors.lastname: Unruh
authors.forename: Berit
authors.initials: B
authors.lastname: Rabausch
authors.forename: Jacques E
authors.initials: JE
authors.lastname: Nör
authors.forename: Jochen W U
authors.initials: JW
authors.lastname: Fries
authors.forename: Claudia
authors.initials: C
authors.lastname: Gottstein
mesh_terms: D020533:Angiogenesis Inhibitors / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D000818:Animals; D001780:Blood Coagulation Tests; D018288:Carcinoma, Small Cell / Q000098:blood supply / Q000188:drug therapy; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006689:Hodgkin Disease / Q000188:drug therapy / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000098:blood supply / Q000188:drug therapy; D051379:Mice; D008833:Microcirculation / Q000187:drug effects; D009336:Necrosis; D009374:Neoplasms, Experimental / Q000098:blood supply* / Q000188:drug therapy*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D012107:Research Design; D020349:Surface Plasmon Resonance; D014183:Transplantation, Heterologous; D019010:Vascular Cell Adhesion Molecule-1 / Q000187:drug effects*
chemical_list: D020533:Angiogenesis Inhibitors; D011993:Recombinant Fusion Proteins; D019010:Vascular Cell Adhesion Molecule-1