2-(二-2-吡啶基亚甲基)-N,N-二甲基肼基硫代甲酰胺

Target: Iron chelator

Dp44mT is cytotoxic to breast cancer cells, at least in part, due to selective inhibition of top2α. Dp44mT alone induced selective cell killing in the breast cancer cell line MDA-MB-231 when compared with healthy mammary epithelial cells (MCF-12A). It induces G1 cell cycle arrest and reduces cancer cell clonogenic growth at nanomolar concentrations. Dp44mT, but not the iron chelator desferal, induces DNA double-strand breaks quantified as S139 phosphorylated histone foci (γ-H2AX) and Comet tails induced in MDA-MB-231 cells. Doxorubicin-induced cytotoxicity and DNA damage are both enhanced significantly in the presence of low concentrations of Dp44mT. The chelator caused selective poisoning of DNA topoisomerase IIα (top2α) as measured by an in vitro DNA cleavage assay and cellular topoisomerase-DNA complex formation. Dp44mT targets lysosome integrity through copper binding. Copper binding is essential for the potent antitumor activity of Dp44mT, as coincubation with nontoxic copper chelators markedly attenuated its cytotoxicity.