Chelators slow cancer growth

A new class of iron chelators has potent anticancer properties, according to a report (Proc. Natl. Acad. Sci. USA, DOI: 10. 1073/pnas.0604979103). Prem Ponka of McGill University, Montreal, and Des R. Richardson and coworkers at Children's Cancer Institute Australia for Medical Research, Sydney, identified di-2-pyridylketone-4,4-dimethyl-3-thiosemicarbazone (Dp44mT, shown) as the most efficient of these chelators. Dp44mT was effective against a variety of tumor types, including those that are resistant to other chemotherapeutics. The chelator doesn't significantly reduce the amount of iron in the cancer cells, the authors note, suggesting that it works by forming a complex that is toxic to tumors rather than by depleting iron. Dp44mT worked at doses as low as 0.4 mg/kg, but doses of 0.75 mg/kg caused irreversible heart damage in the mice. The next step will be to use the chelator as a starting point to find other members of the class that are effective against cancer cells without the toxicity.