[32P]ATP inhibits the growth of xenografted tumors in nude mice.

The search for new therapeutic agents that are effective against cancer has been difficult and expensive. The activity of anticancer candidate agents against human cancer-derived cell lines in immunocompromised mice is an important tool in this search. Because ATP is a naturally occurring small molecule, its radiolabeled form poses many advantages as a potential anticancer therapeutic agent. We previously found that a single, low-dose intravenous injection of [ ( 32) P]ATP inhibited the growth of xenografted tumors in nude mice for up to several weeks. The current study describes the biodistribution and the results and advantages of multi-dose administration of this potential drug. Future studies should investigate the mechanism involved in the possible use of [ ( 32) P]ATP as a cytotoxic agent that homes naturally to the tumor microenvironment.