Design, synthesis and evaluation of 2,4-diaminoquinazoline derivatives as potential tubulin polymerization inhibitors.

Microtubules are highly dynamic polymers composed of alpha- and beta-tubulin proteins that have been shown to be potential therapeutic targets for the development of anticancer drugs. Currently, a wide variety of chemically diverse agents that bind to beta-tubulin have been reported. Nocodazole (NZ) and colchicine (COL) are well-known tubulin-depolymerizing agents that have close binding sites in the beta-tubulin. In this study, we designed and synthesized a set of nine 2,4-diaminoquinazoline derivatives that could occupy both NZ and COL binding sites. The synthesized compounds were evaluated for their antiproliferative activities against five cancer cell lines (PC-3, HCT-15, MCF-7, MDA-MB-231, and SK-LU-1), a noncancerous one (COS-7), and peripheral blood mononuclear cells (PBMC). The effect of compounds4 eand4 ion tubulin organization and polymerization was analyzed on the SK-LU-1 cell line by indirect immunofluorescence, western blotting, and tubulin polymerization assays. Our results demonstrated that both compounds exert their antiproliferative activity by inhibiting tubulin polymerization. Finally, a possible binding pose of4 iin the NZ/COL binding site was determined by using molecular docking and molecular dynamics (MD) approaches. To our knowledge, this is the first report of non-N-substituted 2,4-diaminoquinazoline derivatives with the ability to inhibit tubulin polymerization.