Diaryl terephthalamides as small-molecule disruptors of the c-Myb-CBP/p300 KIX protein-protein interaction: Mechanistic insights and biochemical validation.

The interaction between the transcription factor c-Myb and the CBP/p300 KIX domain is a functionally important protein-protein interface that supports oncogenic transcriptional programs in acute myeloid leukemia and therefore represents an attractive target for inhibitor discovery. Herein, we investigated diaryl terephthalamides as a new small-molecule chemotype for disruption of the c-Myb-CBP/p300 KIX interaction by integrating computational screening with experimental validation. A virtual-screening workflow was applied to a library diaryl terephthalamide derivatives affording five hit compounds (C1-C5). Docking and simulation results showed that C1 and C4 most consistently occupied the c-Myb-facing groove, whereas C5 adopted a distinct but still stable KIX-associated binding mode. Protein-protein interaction metrics calculations indicated that all five compounds weakened the c-Myb-KIX interface to varying extents, with C4 showing the strongest predicted disruptive effect and the most favorable ligand binding free energy, while C5 also exhibited substantial activity. MM/PBSA-based protein-protein interaction perturbation analysis further showed that all five compounds produced positive ΔΔGPPI values, consistent with weakening of the c-Myb-CBP/p300 KIX interface, with C4 and C5 showing the largest predicted disruptive effects (+25.85 and + 18.27 kcal/mol, respectively). Free-energy landscape analysis further supported stable low-energy binding states for C1 and C4, whereas C3 showed greater conformational heterogeneity. In silico ADMET profiling suggested that the series satisfies basic drug-likeness criteria but still carries notable developability liabilities requiring future optimization. Experimental microscale thermophoresis confirmed direct disruption of the Myb-KIX interaction, with C4 and C5 showing the best inhibitory potency, yielding IC50 values of 27.72 ± 7.80 and 27.11 ± 7.45 μM, respectively, compared with 34.74 ± 12.93 μM for Naphthol AS-E phosphate. Consistent with these biochemical findings, C4 and C5 showed the strongest reduction in AML cell viability in HL-60 and THP-1 cells. Overall, these findings identify diaryl terephthalamides as promising c-Myb-CBP/p300 KIX disruptors and establish C4 and C5 as the most compelling leads for further medicinal-chemistry development.