Synthesis, in vitro anticancer activity and in silico studies of certain pyrazole-based derivatives as potential inhibitors of cyclin dependent kinases (CDKs).

New diphenyl-1H-pyrazoles were synthesized and screened for CDK2 inhibition where 8d, 9b, 9c, and 9e exhibited promising activity (IC50 = 51.21, 41.36, 29.31, and 40.54 nM respectively) compared to R-Roscovitine (IC50 = 43.25 nM). Furthermore, preliminary anti-proliferative activity screening of some selected compounds on 60 cancer cell lines was performed at the (NCI/USA). Compounds 8a-c displayed promising growth inhibitory activity (mean %GI; 73.74, 94.32 and 74.19, respectively). Additionally, they were further selected by the NCI for five-dose assay, exhibiting pronounced activity against almost the full panel (GI50 ranges; 0.181-5.19, 1.07-4.12 and 1.07-4.82 µM, respectively) and (Full panel GI50 (MG-MID); 2.838, 2.306 and 2.770 µM, respectively). Screening the synthesized compounds 8a-c for inhibition of CDK isoforms revealed that compound 8a exhibited nearly equal inhibition to all the tested CDK isoforms, while compound 8b inhibits CDK4/D1 preferentially than the other isoforms and compound 8c inhibits CDK1, CDK2 and CDK4 more than CDK7. Flow cytometry cell cycle assay of 8a-c on Non-small cell lung carcinoma (NSCL HOP-92) cell line revealed S phase arrest by 8a and G1/S phase arrest by 8b and 8c. Apoptotic induction in HOP-92 cell line was also observed upon treatment with compounds 8a-c. Docking to CDK2 ATP binding site revealed similar interactions as the co-crystallized ligand R-Roscovitine (PDB code; 3ddq). These findings present compounds 8a-c as promising anti-proliferative agents.