Discovery of quinazolinyl-containing benzamides derivatives as novel HDAC1 inhibitors with in vitro and in vivo antitumor activities

Trifluoromethyl quinoline derivative targets inhibiting HDAC1 for promoting the acetylation of histone in cervical cancer cells

Cervical cancer is the leading cause of death among gynecological malignant tumors, especially due to the poor prognosis of patients with advanced tumors due to recurrence, metastasis, and chemotherapy resistance. Therefore, exploring new antineoplastic drugs with high efficacy and low toxicity may bring new expectations in patients with cervical cancer. Natural products and their derivatives exert an antitumor activity. Therefore, in this work, combined with network pharmacology analysis and experimental validation, we investigated the anti-cervical cancer activity and molecular mechanism of a new trifluoromethyl quinoline (FKL) derivative in vivo and in vitro. FKL117 inhibited the proliferation of cervical cancer cells in a dose and time-dependent manner, induced apoptosis in HeLa cells, arrested the cell cycle in the G2/M phase, and regulated the expression of the apoptotic and cell cycle-related proteins Bcl-2, Bax, cyclin B1, and CDC2. We used online databases to obtain HDAC1 as one of the possible targets of FKL117 and the target binding and binding affinity were modeled by molecular docking. The results showed that FKL117 formed a hydrogen bond with HDAC1 and had good binding ability. We found that FKL117 targeted to inhibit the expression and function of HDAC1 and increased the acetylation of histone H3 and H4, which was also confirmed in vivo. The migration of HMGB1 from the nucleus to the cytoplasm further verified the above results. In conclusion, our study suggested that FKL117 might be used as a novel candidate for targeting the inhibition of HDAC1 against cervical cancer.

N-(2-Aminophenyl)-benzamide Inhibitors of Class I HDAC Enzymes with Antiproliferative and Antifibrotic Activity

Inhibitors of histone deacetylases (HDACs) have received special attention as novel anticancer agents. Among various types of synthetic inhibitors, benzamides constitute an important class, and one is an approved drug (chidamide). Here, we present a novel class of HDAC inhibitors containing the N-(2-aminophenyl)-benzamide functionality as the zinc-binding group linked to various cap groups, including the amino acids pyroglutamic acid and proline. We have identified benzamides that inhibit HADC1 and HDAC2 at nanomolar concentrations, with antiproliferative activity at micromolar concentrations against A549 and SF268 cancer cell lines. Docking studies shed light on the mode of binding of benzamide inhibitors to HDAC1, whereas cellular analysis revealed downregulated expression of EGFR mRNA and protein. Two benzamides were investigated in a mouse model of bleomycin-induced pulmonary fibrosis, and both showed efficacy on a preventative dosing schedule. N-(2-Aminophenyl)-benzamide inhibitors of class I HDACs might lead to new approaches for treating fibrotic disorders.

Elucidation of bioinformatic-guided high-prospect drug repositioning candidates for DMD via Swanson linking of target-focused latent knowledge from text-mined categorical metadata

Duchenne Muscular Dystrophy (DMD)'s complex multi-system pathophysiology, coupled with the cost-prohibitive logistics of multi-year drug screening and follow-up, has hampered the pursuit of new therapeutic approaches. Here we conducted a systematic historical and text mining-based pilot feasibility study to explore the potential of established or previously tested drugs as prospective DMD therapeutic agents. Our approach utilized a Swanson linking-inspired method to uncover meaningful yet largely hidden deep semantic connections between pharmacologically significant DMD targets and drugs developed for unrelated diseases. Specifically, we focused on molecular target-based MeSH terms and categories as high-yield bioinformatic proxies, effectively tagging relevant literature with categorical metadata. To identify promising leads, we comprehensively assembled published reports from 2011 and sampling from subsequent years. We then determined the earliest year when distinct MeSH terms or category labels of the relevant cellular target were referenced in conjunction with the drug, as well as when the pertinent target itself was first conclusively identified as holding therapeutic value for DMD. By comparing the earliest year when the drug was identifiable as a DMD treatment candidate with that of the first actual report confirming this, we computed an Index of Delayed Discovery (IDD), which serves as a metric of Swanson-linked latent knowledge. Using these findings, we identified data from previously unlinked articles subsetted via MeSH-derived Swanson linking or from target classes within the DrugBank repository. This enabled us to identify new but untested high-prospect small-molecule candidates that are of particular interest in repurposing for DMD and warrant further investigations.

Discovery of Indole-Containing Benzamide Derivatives as HDAC1 Inhibitors with In Vitro and In Vivo Antitumor Activities

Targeting histone deacetylases (HDACs) has become an important focus in cancer inhibition. The pharmacophore of HDAC inhibitors (HDACis) reported so far is composed of three parts: a zinc-binding group (ZBG), a hydrophobic cavity-binding linker, and a surface-recognition cap interacting with HDAC surface located at the rim of active site cavity. This study aims to discover novel HDAC1 inhibitors with potent antitumor activities through modifying the cap and ZBG based on the structures of two marketed oral HDACis: chidamide and entinostat (MS-275). In this work, a series of benzamide derivatives were designed, synthesized, and evaluated for their antitumor activity. The structures of novel compounds were confirmed by 1H NMR (nuclear magnetic resonance) and ESI-MS (electrospray ionization mass spectrometry), and all target compounds were tested in both HDAC1 enzymatic inhibitory activity and cellular antiproliferative activity. Our data showed that the potent compound 3j exhibited good HDAC1 enzyme inhibitory activity and high antitumor cell proliferation activity against a selected set of cancer cells (PC-3, HCT-116, HUT-78, Jurkat E6–1, A549, Colo205, and MCF-7 cells) with no observed effects on human normal cells. In particular, compound 3j inhibited HDAC1 over the other tested HDAC isoforms (HDAC2, HDAC6, and HDAC8). Encouraged by this, the safety characteristics, molecular docking, preliminary pharmacokinetic characteristics, and antitumor effect in vivo of compound 3j were further investigated. Our data showed that compound 3j demonstrated acceptable safety profiles and favorable oral pharmacokinetic properties. Moreover, compound 3j could bind well with HDAC1 and showed significant antitumor activity in a PC-3 tumor xenograft model in vivo, though not as potent as positive control entinostat (MS-275). In summary, 3j might have therapeutic potential for the treatment of human cancers.

Design, Synthesis, and Evaluation of Benzoheterocyclic-Containing Derivatives as Novel HDAC1 Inhibitors

In this study, the synthesis and biological evaluation of a variety of benzoheterocyclic-containing benzamide derivatives were described. Some of these compounds were proved to inhibiting the activity of histone deacetylase 1 (HDAC1) with IC50 values below the micromolar range, retarding proliferation of several human cancer cells, and surprisingly, not possessing toxicity to human normal cells and hERG K+ ion channels. Among those compounds, 3c was the most potent and efficacious derivative. Compound 3c was orally active and displayed excellent in vivo antitumor activity in a HCT-116 xenograft mice model.