Novel Aminopyrimidine-2,4-diones, 2-Thiopyrimidine-4-ones, and 6-Arylpteridines as Dual-Target Inhibitors of BRD4/PLK1: Design, Synthesis, Cytotoxicity, and Computational Studies.

Structural-based drug design and solvent-free synthesis were combined to obtain three novel series of 5-arylethylidene-aminopyrimidine-2,4-diones (, -, ,), 5-arylethylidene-amino-2-thiopyrimidine-4-ones (,), and 6-arylpteridines (,) as dual BRD4 and PLK1 inhibitors. MTT assays of synthesized compounds against breast (MDA-MB-231), colorectal (HT-29), and renal (U-937) cancer cells showed excellent-to-good cytotoxic activity, compared to Methotrexate; MDA-MB-231 were the most sensitive cancer cells. The most active compounds were tested against normal Vero cells. Compounds and significantly inhibited BRD4 and PLK1, with IC values of 0.029, 0.042 µM, and 0.094, 0.02 µM, respectively, which are nearly comparable to volasertib (IC = 0.017 and 0.025 µM). Compound triggered apoptosis and halted cell growth at the G2/M phase, similarly to volasertib. It also upregulated the BAX and caspase-3 markers while downregulating the Bcl-2 gene. Finally, active compounds fitted the volasertib binding site at BRD4 and PLK1 and showed ideal drug-like properties and pharmacokinetics, making them promising anticancer candidates.