Design and synthesis of 1H-benzo[d]imidazole selective HDAC6 inhibitors with potential therapy for multiple myeloma

Design, synthesis and evaluation of structural optimization derived HDAC6 isoform-selective inhibitor

In stark contrast to other HDAC isoforms, deletion or inhibition of HDAC6 suppresses cell proliferation without lethality or defective phenotypes, thereby establishing HDAC6 as a compelling anti-cancer target. In pursuit of safe and effective anti-cancer chemotherapy, we preformed three-round structural optimization and developed several potent HDAC6-selective inhibitors. Among these, HDSI-18 exhibited remarkable inhibitory activity (IC50 = 1.6 nM) and exceptional isoform selectivity (over 975-fold) against HDAC6. Further biological evaluations highlighted the promising properties of HDSI-18 in terms of anti-proliferative activity, mitochondrial depolarization, caspase-3 activation, apoptosis induction and druggability (both in vivo and in vitro). This study demonstrated a paradigm for the rational structural optimization of HDAC6 selective inhibitors, which may serve as a beacon for the development of more promiscuous compounds.

Imidazole Hybrids: A Privileged Class of Heterocycles in Medicinal Chemistry with New Insights into Anticancer Activity

Imidazole is a five-membered heterocyclic system featuring two nitrogen heteroatoms at the 1- and 3-positions of the ring. The imidazole scaffold is particularly suited for kinase inhibition concepts. This further confirms that this scaffold is a privileged structure in the development of anticancer drugs. Considering these key factors and the recent focus of scientists on imidazole compounds, we discuss the anticancer activities of imidazole-containing hybrids and related compounds, highlighting articles published in 2023 that serve as a basis for medicinal chemistry leads. From a chemical perspective, the present review emphasizes hybrid molecules with an imidazole ring in the side chain, imidazole-centered hybrid molecules, condensed imidazole hybrids, hybrid compounds containing two or more imidazole rings, polycyclic imidazole hybrids, imidazole-containing metal complexes, and benzimidazole hybrids.

HDAC6 mediates tumorigenesis during mitosis and the development of targeted deactivating agents

Epigenetics, particularly deacetylation, plays a critical role in tumorigenesis as many carcinogens are under tight control by post-translational modification. HDAC6, an important and special histone deacetylase (HDAC) family member, has been indicated to increase carcinogenesis through various functions. Recent studies demonstrated the effects of HDAC6 inhibitors in mitotic arrest, however, detailed mechanisms still remain unknown. Herein, we review and summarize HDAC6-associated proteins that have been implicated in important roles in mitosis. We also discuss the development of medicinal agents targeting HDAC6.

Balancing the interplay of histone deacetylases and non-coding genomes: a step closer to understand the landscape of cancer treatment

Histone deacetylase (HDAC) inhibitors have enormous therapeutic potential as effective epigenetic regulators, and now with the focus on the selective HDAC6 inhibitor in ongoing clinical trials, more advantages over other non-selective pan-HDAC inhibitors are foreseeable. As it is of paramount importance to understand the complex regulatory web of mutual interactions involving epigenetic machinery and non-coding genome in regulating gene expression, herein, we investigated the intriguing interactions between HDAC6-induced lncRNA (LINC00152) and its possible sponge miRNA (hsa-miR-499a-5p) in multiple myeloma.