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 EGFR^WT/ EGFR^T790M kinase inhibitory activity (regarding EGFR^WT, IC₅₀ = 0.136 and 0.133 μM, respectively), (regarding EGFR^T790M, 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 EGFR^WT 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 EGFR^WT/ EGFR^T790M kinase inhibitors.

Antitumor; Apoptosis; EGFR(WT)/ EGFR(T790M) inhibitors; Molecular docking; Molecular dynamics simulations; Pyridazinone.