Angiostatin-like activity of a monoclonal antibody to the catalytic subunit of F1F0 ATP synthase

Cancer Res. 2007 May 15;67(10):4716-24. doi: 10.1158/0008-5472.CAN-06-1094.

Abstract

The antiangiogenic protein angiostatin inhibits ATP synthase on the endothelial cell surface, blocking cellular proliferation. To examine the specificity of this interaction, we generated monoclonal antibodies (mAb) directed against ATP synthase. mAb directed against the beta-catalytic subunit of ATP synthase (MAb3D5AB1) inhibits the activity of the F(1) domain of ATP synthase and recognizes the catalytic beta-subunit of ATP synthase. We located the antibody recognition site of MAb3D5AB1 in domains containing the active site of the beta-subunit. MAb3D5AB1 also binds to purified Escherichia coli F(1) with an affinity 25-fold higher than the affinity of angiostatin for this protein. MAb3D5AB1 inhibits the hydrolytic activity of F(1) ATP synthase at lower concentrations than angiostatin. Like angiostatin, MAb3D5AB1 inhibits ATP generation by ATP synthase on the endothelial cell surface in acidic conditions, the typical tumor microenvironment where cell surface ATP synthase exhibits greater activity. MAb3D5AB1 disrupts tube formation and decreases intracellular pH in endothelial cells exposed to low extracellular pH. Neither angiostatin nor MAb3D5AB1 showed an antiangiogenic effect in the corneal neovascularization assay; however, both were effective in the low-pH environment of the chicken chorioallantoic membrane assay. Thus, MAb3D5AB1 shows angiostatin-like properties superior to angiostatin and may be exploited in cancer chemotherapy.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adenosine Triphosphate / biosynthesis
  • Angiostatins / metabolism*
  • Animals
  • Antibodies, Monoclonal / immunology*
  • Antibodies, Monoclonal / metabolism
  • Antibodies, Monoclonal / pharmacology*
  • Binding Sites, Antibody
  • Biomimetic Materials
  • Catalytic Domain / immunology
  • Cattle
  • Chorioallantoic Membrane / blood supply
  • Corneal Neovascularization / drug therapy
  • Endothelial Cells / cytology
  • Endothelial Cells / drug effects
  • Epitope Mapping
  • Female
  • Humans
  • Hydrogen-Ion Concentration
  • Mice
  • Mice, Inbred BALB C
  • Mitochondrial Proton-Translocating ATPases / antagonists & inhibitors
  • Mitochondrial Proton-Translocating ATPases / immunology*
  • Mitochondrial Proton-Translocating ATPases / metabolism
  • Models, Molecular
  • Neovascularization, Physiologic / drug effects
  • Rats
  • Rats, Inbred F344

Substances

  • Antibodies, Monoclonal
  • Angiostatins
  • Adenosine Triphosphate
  • F1F0-ATP synthase
  • Mitochondrial Proton-Translocating ATPases