New imidazole-coordinated chemotherapeutics with low epithelial toxicity

The new imidazole-coordinated chemotherapeutics with low epithelial toxicity (NICE) presented in this article feature innovative drugs that combine epithelial toxicity comparable with that of carboplatin with novel carrier ligands optimized for DNA interaction. Recent identification of the pivotal role of basolateral organic cation transporters (OCTs) in cisplatin nephrotoxicity by a new model system (electrical resistance breakdown assay) facilitated the search for substances with a favorable organotoxic profile. The assay uses the high transepithelial electrical resistance (TEER) of the C7-clone of Madin-Darby canine kidney (MDCK) cells and the exclusive basolateral expression of OCT2 in these cells. TEER and caspase-3 activity of MDCK-C7-cells grown on microfilter membranes were monitored in response to exposure of either the apical or basolateral plasma membrane to platinum complexes. The impact of complexes on cancer cell lines was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bomide tests. Effects of substituents on pharmacological properties of NICE were systematically investigated by introducing sterically demanding groups as well as electron-donating and electron-withdrawing groups. Derivatives of NICE showed different renal epithelial toxic profiles and effects on cancer cells. NICE were significantly less toxic than cis-or oxaliplatin. The chlorine substituted NICE had no effect on epithelial integrity but markedly cytotoxic activity against amelanotic melanoma cells. Together, side effect targeted screening for new anticancer drugs with the electrical resistance breakdown assay offers an interesting approach for identifying and investigating new compounds. NICE feature the first group of platinum-based cytostatics discovered by using this system for systematic screening of new chemotherapeutics with low renal epithelial toxicity.