Design, Synthesis, and Biological Evaluation of N,N-Diphenylaniline-Based Derivatives as Antiproliferative Agents and ABL TK Inhibitors Against CML

<b>Background/Objectives</b>: Targeting ABL tyrosine kinase (TK) remains a cornerstone of chronic myeloid leukemia (CML) therapy. <b>Methods:</b> In this study, a series of novel 4-((2-(4-(aryl)thiazol-2-yl)hydrazineylidene)methyl)-<i>N</i>,<i>N</i>-diphenylaniline derivatives (<b>1-12</b>) were synthesized through the reaction of 2-(4-(diphenylamino)benzylidene)hydrazine-1-carbothioamide (intermediate <b>A</b>) with substituted 2-bromo-1-arylethanones. Cytotoxic activity was evaluated in K562 CML cells using the MTT assay. The most active compound was further assessed in HL-60 acute myeloid leukemia (AML) cells and healthy peripheral blood mononuclear cells (PBMCs). Apoptosis induction was analyzed by Annexin V/ethidium homodimer staining, while ABL TK inhibition was determined using the ADP-Glo kinase assay. Molecular docking studies were performed to investigate binding interactions within the ATP-binding site of ABL TK, and pharmacokinetic properties were also predicted. <b>Results:</b> Intermediate <b>A</b> demonstrated superior antiproliferative activity compared to derivatives <b>1-12</b> and exhibited cytotoxicity comparable to imatinib in K562 cells (IC₅₀ = 6.15 ± 1.26 µM vs. 5.14 ± 1.44 µM, respectively). In HL-60 cells, intermediate <b>A</b> showed an IC₅₀ of 12.04 ± 1.70 µM, similar to imatinib. Notably, intermediate <b>A</b> displayed enhanced selectivity toward K562 cells over PBMCs (SI = 12.9) relative to imatinib (SI = 6.2). The compound significantly induced apoptosis in K562 cells and inhibited ABL TK activity. Docking studies revealed a distinct binding orientation within the ATP-binding pocket of ABL TK. The compound showed acceptable predicted physicochemical and ADME characteristics based on in silico analysis. <b>Conclusions:</b> Intermediate <b>A</b> emerges as a significant anti-CML candidate exhibiting potent cytotoxic, apoptotic, and moderate ABL TK inhibitory activity, together with a favorable selectivity profile.