Urea derivatives as anticancer agents.

Within the past ten years, a huge volume of research on the synthesis, structure-activity relationships (SAR), and anticancer activities of the urea derivatives was reported. Many aromatic urea derivatives such as N-phenyl-N'-(2-chloroethyl)ureas (CEUs) and benzoylureas (BUs) show good anticancer activity, and these compounds have mainly been proved to be tubulin ligands that inhibit the polymerization of tubulin. Heterocyclic urea derivatives play an important role in anticancer agents because of their good inhibitory activity against receptor tyrosine kinases (RTKs), raf kinases, protein tyrosine kinases (PTKs), and NADH oxidase, which play critical roles in many aspects of tumorigenesis. Thiourea derivatives are also of wide interest because of their diverse anticancer activity against various leukemias and solid tumors. In this review, the anticancer activity of the urea derivatives mentioned above is summarized in detail. It is hoped that increasing knowledge of the SAR and cellular processes underlying the antitumor-activity of urea derivatives will be beneficial to the rational design of new generation of urea anticancer drugs.