Synthesis and anticancer evaluation of novel pyrrole-pyrido[2,3-d] pyrimidine-based compounds as thymidylate synthase inhibitors

Cancer is an abnormal growth of cells and major cause of death globally. As an important part of DNA biosynthesis, thymidylate synthase (TS) has garnered attention as a potential target for cancer therapy. In this work, we developed and synthesized 22 nobel pyrido[2,3-d]pyrimidine/alkylated pyrido[2,3-d]pyrimidines based on pyrrole/alkylated pyrrole and evaluated their anti-proliferative efficacy against PC-3, Hep G2, A549, and HCT 116 cell lines. For compounds IIId, and IVb, TS inhibitory activity was also performed along with in silico studies. Further, all the synthesized compounds exhibited anti-proliferative activity, but particularly, compounds IIId, and IVb were showed excellent anti-proliferative activity having IC50 values of 2.601+ 0.66, 3.554+0.69, 4.482+1.41, and 9.869+1.08 mu M; and, 1.182+1.06, 1.801+ 0.92, 4.787+1.51, and 7.174+1.18 mu M respectively with control raltitrexed (IC50 1.813+1.46, 2.091+1.11, 2.816+0.19, and 3.215+0.91 mu M, respectively) and IC50 values for hTS inhibitory action were 20.782+0.08 and 15.502+0.11 nM, respectively, compared to 13.254+0.52 nM for control raltitrexed. Moreover, molecular docking, which demonstrated the binding pattern of IVb to the TS catalytic site, and molecular dynamics simulations, which examined the conformational behavior and stability of compound IVb over a 100 ns period, corroborated the inhibitory mechanism. Furthermore, these compounds' ADME properties fell within the permissible range. SAR was also carried out for lead optimization based on the anti-proliferative effect.