Discovery of iminobenzimidazole derivatives as novel cytotoxic agents

In our quest to identify inhibitors of the eukaryotic translation initiation factor 4F (eIF4F), we serendipitously discovered a novel cytotoxic agent. Even though this compound did not inhibit translation, we explored the structural requirements for its cytotoxicity due to its structural originality. A series of 1,3-disubstituted iminobenzimidazoles was synthesized and evaluated for their in vitro cytotoxicity. The structure-activity relationship studies demonstrate that hydrophobic substituent is essential for activity. The most active compounds displayed a cytotoxicity in KB, HL60 and HCT116 human cancer cells with an IC₅₀ of about 1μM. These first-in-class series of low molecular weight synthetic molecules may provide the basis for the development of new anticancer drugs.