Acidic fibroblast growth factor-Pseudomonas exotoxin chimeric protein elicits antiangiogenic effects on endothelial cells

Cancer Res. 1992 Sep 15;52(18):4995-5001.

Abstract

It has recently been shown that chimeric toxins composed of acidic fibroblast growth factor fused to mutant forms of Pseudomonas exotoxin (aFGF-PE) are cytotoxic to a variety of tumor cell lines with FGF receptors. Although aFGF-PE might be considered as a possible chemotherapeutic toxin, limited knowledge is available concerning its effect on endothelia. This study investigates whether one of the aFGF-PE fusion proteins, aFGF-PE664GluKDEL, can function as an anti-angiogenic agent. Protein synthesis studies using rat epididymal fat pad microvascular endothelial cells (RFCs) indicated that after 24 h in culture, aFGF-PE had a significant inhibitory effect on protein synthesis at concentrations greater than 100 ng/ml. In cultures incubated with 1000 ng/ml aFGF-PE, RFC protein synthesis was inhibited as much as 83%. RFCs were also cultured in a 3-dimensional type I collagen gel and incubated with either transforming growth factor beta 1, aFGF-PE, or a combination of both. Transforming growth factor beta 1 elicits in vitro angiogenesis in these 3-dimensional cultures which consist of rapid formation of complex tubular structures. Transforming growth factor beta 1-treated RFCs incubated with aFGF-PE were unable to produce this angiogenic response, nor were they able to migrate out of the 3-dimensional culture to form a monolayer as shown by controls. Cell viability analyses showed that aFGF-PE produced a dose-dependent toxic effect which ranged from 10 to 90% cell death. Competition assays in which the chimeric toxin was preincubated with antibodies to aFGF resulted in an 89% reversal of the inhibitory effects of aFGF-PE on endothelial cells. Acidic FGF-PE with a mutation in the ADP ribosylation domain of PE was inactive in both 2-dimensional and 3-dimensional cultures. These data show that aFGF-PE has specific in vitro cytotoxic, antiangiogenic, and antimigratory effects on microvascular endothelia.

MeSH terms

  • ADP Ribose Transferases*
  • Amino Acid Sequence
  • Animals
  • Bacterial Toxins*
  • Cell Movement / drug effects
  • Cell Survival / drug effects
  • Cells, Cultured
  • Endothelium, Vascular / drug effects*
  • Exotoxins / administration & dosage*
  • Exotoxins / chemistry
  • Fibroblast Growth Factor 1 / chemistry*
  • In Vitro Techniques
  • Molecular Sequence Data
  • Neovascularization, Pathologic*
  • Pseudomonas aeruginosa Exotoxin A
  • Rats
  • Rats, Inbred Strains
  • Receptors, Cell Surface / metabolism
  • Receptors, Fibroblast Growth Factor
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / toxicity
  • Virulence Factors*

Substances

  • Bacterial Toxins
  • Exotoxins
  • Receptors, Cell Surface
  • Receptors, Fibroblast Growth Factor
  • Recombinant Fusion Proteins
  • Virulence Factors
  • Fibroblast Growth Factor 1
  • ADP Ribose Transferases