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 µM). 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.

ANKHD1 contributes to the malignant phenotype of triple-negative breast cancer cells.

Ankyrin repeat and KH domain-containing protein 1, ANKHD1, has been identified as a regulator of signaling pathways and cellular processes of relevance in carcinogenesis. However, the role of ANKHD1 in breast cancer remains unclear. The aim of the present study was to characterize the expression pattern and involvement of ANKHD1 in the malignant phenotype of breast cancer cell lines and to investigate the clinical relevance of ANKHD1 in a breast cancer context. Gene and protein expressions were assessed in the cell lines by quantitative reverse transcription PCR and Western blot analysis, respectively, and ANKHD1 silencing through siRNA transfection was conducted for further in vitro functional assays. The expression of ANKHD1 was identified in non-tumorigenic breast epithelium and breast cancer cell lines, but differences in cellular localization were found among the neoplasia subtypes. ANKHD1 silencing reduced the viability, clonogenicity, and migration of triple-negative breast cancer (TNBC) cells. Bioinformatics analyses demonstrated that patients with triple-negative basal-like 2 and mesenchymal breast cancer subtypes had high ANKHD1 expression associated with poor recurrence-free survival. Therefore, these data indicate that ANKHD1 relevance in breast cancer varies among its subtypes, indicating the importance of ANKHD1 in TNBC.