In vitro and in vivo evaluation of a Cu-64-labeled propylene amine oxime complex as a potential hypoxia imaging agent bearing two 3-nitrotriazole groups

The propylene amine oxime (PnAO) ligand, PnAO-1, 1'-bis(3-nitrotriazole) (3P3) with two 3-nitrotriazole groups was labeled with (CuCl2)-Cu-64. In vitro results suggest that Cu-64-3P3 can accumulate in hypoxic S180 tumor cells. Biodistribution studies of Cu-64-3P3 in mice bearing S180 tumor demonstrate that the tumor uptake, tumor-to-muscle ratio, and tumor-to-blood ratio are considerable. A tumor area could also be found in positron emission tomography imaging 18 h post-administration. For comparison, the classical hypoxia imaging agent Cu-64-ATSM was also investigated. The experimental data obtained demonstrate that Cu-64-3P3 may potentially be used as an efficient hypoxia imaging agent.