Discovery, synthesis, and investigation of the antitumor activity of novel piperazinylpyrimidine derivatives.

Protein kinases play several pertinent roles in cell proliferation, and targeting these proteins has been shown to be a successful strategy toward controlling different malignancies. Despite the great discovery stories during the last two decades, there is still a demand for anticancer small molecules with the potential of being selective on both the protein kinase and/or the cellular level. A series of novel piperazinylpyrimidine compounds were synthesized and tested for their potential to selectively inhibit the growth of certain tumor cell lines included within the NCI-60 cell line panel. MDA-MB-468, a triple-negative/basal-like breast carcinoma, cell line was among the most sensitive cell lines towards compounds 4 and 15. The three most interesting compounds identified in cellular screens (4, 15, and 16) were subjected to kinase profiling and found to have an interesting selective tendency to target certain kinase subfamily members; PDGFR, CK1, RAF and others. Compound 4 showed a selective tendency to bind to and/or inhibit the function of certain KIT and PDGFRA mutants compared to their wild-type isoforms. Piperazinylpyrimidine based derivatives represent a new class of selective kinase inhibitors. Significantly 4 is more potent at inhibiting oncogenic mutant forms of PDGFR family kinases, which is relevant in terms of its potential use in treating tumors that have become resistant to treatment or driven by such mutations. The clinical demand for agents useful in the control of triple-negative/basal-like breast cancer justifies our interest in compound 15 which is a potent growth inhibitor of MDA-MB-468 cell line.