Discovery of novel pyridazinone derivatives as EGFRWT/ EGFRT790M kinase inhibitors; design, synthesis, antitumor evaluation, and molecular dynamic simulations.

Two new series of pyridazinone derivatives, 4a-h and 5a-d, were designed and synthesized as potent cytotoxic agents against prostate (PC-3), colon (Caco-2), and breast (MDA-231) cancers. The safety of the synthesized derivatives was assessed on normal cell (WISH). Compounds 4a and 5d showed outstanding cytotoxic activity against all tested cell lines (PC-3, Caco-2, and MDA-231) with IC50 values of 11.17, 13.80 & 7.92 μM for 4a, 9.46, 7.45 & 5.92 μM for 5d, respectively, compared to doxorubicin (IC50 of 8.87, 12.49 and 3.18 μM) and sorafenib (IC50 of 11.53, 10.29 and 7.64 μM) respectively. Furthermore, both derivatives exhibited advanced selectivity to the tested cancer cells (SI values of 2.4-5.4) compared to sorafenib (SI values of 1.16-1.8) and doxorubicin (SI values of 0.7-2.7). Additionally, pyridazinone derivatives 4a and 5d exhibited potent EGFRWT/ EGFRT790M kinase inhibitory activity (regarding EGFRWT, IC50 = 0.136 and 0.133 μM, respectively), (regarding EGFRT790M, IC50 = 0.076, 0.043 μM, respectively) compared to Erlotinib (IC50 = 0.189, 0.190 μM, respectively). The most potent derivative 5d inhibits proliferation and apoptosis by inducing cell cycle arrest at the G1/S phase, as demonstrated by cell cycle analysis. Molecular docking of compounds 4a and 5d exhibited strong binding affinities for the active site in a similar pattern to Erlotinib. Moreover, molecular dynamics simulations results revealed that derivatives 4a and 5d forms a more stable and tighter complex with the EGFRWT kinase domain, as evidenced by lower RMSD, higher interaction stability, and a more favorable binding free energy. The aforementioned findings proposed that derivatives 4a and 5d are promising lead for the future design of EGFRWT/ EGFRT790M kinase inhibitors.