Direct targeting of tumor cell F(1)F(0) ATP-synthase by radioiodine angiostatin in vitro and in vivo.

Unlabelled: Recent discoveries have identified endothelial cell-surface F(1)F(0) adenosine triphosphate (ATP) synthase as the key target for angiostatin (AST) action. As this enzyme is also present on tumor cells, we investigated whether radiolabeled AST may directly target cancer cell-surface ATP synthase in vitro and in vivo.

Methods: Cell-binding characteristics of (125)I-AST was evaluated on human umbilical vein endothelial (HUVE) and SNU-C5 colon carcinoma cells.

Distribution and pharmacokinetic analysis of angiostatin radioiodine labeled with high stability.

Objective: Radiotracers of anticancer agents provide important information on its in vivo handling. Angiostatin (AST) is a promising anticancer drug with potent antiangiogenic effects, but reported AST radiotracers suffer from poor in vivo stability. In this study, we synthesized an AST probe radioiodinated via the Bolton-Hunter reagent (125I-BH-AST) and investigated its stability and biokinetics in mice.