HDAC specificity and kinase off-targeting by purine-benzohydroxamate anti-hematological tumor agents

A series of hybrid inhibitors, combining pharmacophores of known kinase inhibitors bearing anilino-purines (ruxolitinib, ibrutinib) and benzohydroxamate HDAC inhibitors (nexturastat A), were generated in the present study. The compounds have been synthesized and tested against solid and hematological tumor cell lines. Compounds 4d-f were the most promising in cytotoxicity assays (IC50 <= 50 nM) vs. hematological cells and displayed moderate activity in solid tumor models (EC50 = 9.3-21.7 mu M). Compound 4d potently inhibited multiple kinase targets of interest for anticancer effects, including JAK2, JAK3, HDAC1, and HDAC6. Molecular dynamics simulations showed that 4d has stable interactions with HDAC and members of the JAK family, with differences in the hinge binding energy conferring selectivity for JAK3 and JAK2 over JAK1. The kinase inhibition profile of compounds 4d-f allows selective cytotoxicity, with minimal effects on non-tumorigenic cells. Moreover, these compounds have favorable pharmacokinetic profiles, with high stability in human liver microsomes (e.g., see t1/2: >120 min for 4f), low intrinsic clearance, and lack of significant inhibition of four major CYP450 isoforms.

Automated summary

A series of hybrid inhibitors combining pharmacophores of known kinase inhibitors and benzohydroxamate HDAC inhibitors were synthesized and evaluated for their anticancer activity and pharmacokinetic properties. Compounds 4d-f exhibited promising cytotoxicity against hematological cells and moderate activity against solid tumor models. Compound 4d showed potent inhibition of multiple kinase targets and had stable interactions with HDAC and members of the JAK family. These compounds showed selective cytotoxicity with minimal effects on non-tumorigenic cells and favorable pharmacokinetic profiles.