Bioactive dihydropyrimidinones (DHPs) were designed and synthesized by a multicomponent Biginelli reaction. The reaction was catalyzed by the polarized surface of nano-zirconium dioxide with partial positive charge of 0.52e at the Zr center and a negative charge of −0.23e at the oxygen center. There was good corroboration between the computed and experimental ZrO2 cell parameters and bond distances as determined by in silico and in vitro experimental methods. Since DHPs were found to target the peroxisome proliferator-activated receptor (PPAR)-γ, we tested these ligands toward MCF-7 cell toxicity, which revealed that the compounds 4d [ethyl-4-(4′-fluoro-[1,1′-biphenyl]-4-yl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate] and 4e [ethyl-4-(3′-methoxy-[1,1′-biphenyl]-4-yl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate] inhibited proliferation with IC50 values of 11.8 and 15.8 μM, respectively. Further, our bioinformatic analysis found that the active molecule 4d, fit into the enzyme’s catalytic site, almost in the same position as rosiglitazone, which was buried deep inside the cavity. In conclusion, we herein report novel DHPs which could be better structures to help explore a new class of synthetic PPAR-γ ligands.

Novel PARP inhibitors with selective mode-of-action have been approved for clinical use. Herein, oxadiazole based ligands that are predicted to target PARP-1 have been synthesized and screened for the loss of cell viability in mammary carcinoma cells, wherein seven compounds were observed to possess significant IC50 values in the range of 1.4 to 25 µM. Furthermore, compound 5u, inhibited the viability of MCF-7 cells with an IC50 value of 1.4µM, when compared to Olaparib (IC50 = 3.2 µM). Compound 5s also decreased cell viability in MCF-7 and MDA-MB-231 cells with IC50 values of 15.3 and 19.2 µM, respectively. Treatment of MCF-7 cells with compounds 5u and 5s produced PARP cleavage, H2AX phosphorylation and CASPASE-3 activation comparable to that observed with Olaparib. Compounds 5u and 5s also decreased foci-formation and 3D Matrigel growth of MCF-7 cells equivalent to or greater than that observed with Olaparib. Finally, in silico analysis demonstrated binding of compound 5s towardsthe catalytic site of PARP-1, indicating that these novel oxadiazoles synthesized herein may serve as exemplars for the development of new therapeutics in cancer.

Small molecules are being used to inhibit cyclin dependent kinase (CDK) enzymes in cancer treatment. There is evidence that CDK is a drug-target for cancer therapy across many tumor types because it catalyzes the transfer of the terminal phosphate of ATP to a protein that acts as a substrate. Herein, the identification of pyranopyrazoles that were CDK inhibitors was attempted, whose synthesis was catalyzed by nano-zirconium dioxide via multicomponent reaction. Additionally, we performed an in-situ analysis of the intermediates of multicomponent reactions, for the first-time, which revealed that nano-zirconium dioxide stimulated the reaction, as estimated by Gibbs free energy calculations of spontaneity. Functionally, the novel pyranopyrazoles were tested for a loss of cell viability using human breast cancer cells (MCF-7). It was observed that compounds 5b and 5f effectively produced loss of viability of MCF-7 cells with IC50 values of 17.83 and 23.79 µM, respectively. In vitro and in silico mode-of-action studies showed that pyranopyrazoles target CDK1 in human breast cancer cells, with lead compounds 5b and 5f having potent IC50 values of 960 nM and 7.16 μM, respectively. Hence, the newly synthesized bioactive pyranopyrazoles could serve as better structures to develop CDK1 inhibitors against human breast cancer cells.