C8-substituted pyrido[3,4-d]pyrimidin-4(3H)-ones: Studies towards the identification of potent, cell penetrant Jumonji C domain containing histone lysine demethylase 4 subfamily (KDM4) inhibitors, compound profiling in cell-based target engagement assays

Derivatives of the Clinically Used HIF Prolyl Hydroxylase Inhibitor Desidustat Are Efficient Inhibitors of Human γ-Butyrobetaine Hydroxylase

The 2-oxoglutarate (2OG)/Fe(II)-dependent γ-butyrobetaine hydroxylase (BBOX) catalyzes the final step in l-carnitine biosynthesis, i.e., stereoselective C-3 oxidation of γ-butyrobetaine (GBB). BBOX inhibition is a validated clinical strategy to modulate l-carnitine levels and to enhance cardiovascular efficiency. Reported BBOX inhibitors, including the clinically used cardioprotective agent Mildronate, manifest moderate inhibitory activity in vitro, limited selectivity, and/or unfavorable physicochemical properties, indicating a need for improved BBOX inhibitors. We report that the clinically used hypoxia-inducible factor-α prolyl residue hydroxylase (PHD) inhibitors Desidustat, Enarodustat, and Vadadustat efficiently inhibit isolated recombinant BBOX, suggesting that BBOX inhibition by clinically used PHD inhibitors should be considered as a possible off-target effect. Structure-activity relationship studies on the Desidustat scaffold enabled development of potent BBOX inhibitors that manifest high levels of selectivity for BBOX inhibition over representative human 2OG oxygenases, including PHD2. The Desidustat derivatives will help to enable investigations into the biological roles of l-carnitine and the therapeutic potential of BBOX inhibition.

The emerging roles of lysine-specific demethylase 4A in cancer: Implications in tumorigenesis and therapeutic opportunities

Lysine-specific demethylase 4 A (KDM4A, also named JMJD2A, KIA0677, or JHDM3A) is a demethylase that can remove methyl groups from histones H3K9me2/3, H3K36me2/3, and H1.4K26me2/me3. Accumulating evidence suggests that KDM4A is not only involved in body homeostasis (such as cell proliferation, migration and differentiation, and tissue development) but also associated with multiple human diseases, especially cancers. Recently, an increasing number of studies have shown that pharmacological inhibition of KDM4A significantly attenuates tumor progression in vitro and in vivo in a range of solid tumors and acute myeloid leukemia. Although there are several reviews on the roles of the KDM4 subfamily in cancer development and therapy, all of them only briefly introduce the roles of KDM4A in cancer without systematically summarizing the specific mechanisms of KDM4A in various physiological and pathological processes, especially in tumorigenesis, which greatly limits advances in the understanding of the roles of KDM4A in a variety of cancers, discovering targeted selective KDM4A inhibitors, and exploring the adaptive profiles of KDM4A antagonists. Herein, we present the structure and functions of KDM4A, simply outline the functions of KDM4A in homeostasis and non-cancer diseases, summarize the role of KDM4A and its distinct target genes in the development of a variety of cancers, systematically classify KDM4A inhibitors, summarize the difficulties encountered in the research of KDM4A and the discovery of related drugs, and provide the corresponding solutions, which would contribute to understanding the recent research trends on KDM4A and advancing the progression of KDM4A as a drug target in cancer therapy.

Exploring the potential of histone demethylase inhibition in multi-therapeutic approaches for cancer treatment

Histone demethylases play a critical role in gene transcription regulation and have been implicated in cancer. Numerous reports have highlighted the overexpression of histone demethylases, such as LSD1 and JmjC, in various malignant tumor tissues, identifying them as effective therapeutic targets for cancer treatment. Despite many histone demethylase inhibitors entering clinical trials, their clinical efficacy has been limited. Therefore, combination therapies based on histone demethylase inhibitors, along with other modulators like dual-acting inhibitors, have gained significant attention and made notable progress in recent years. In this review, we provide an overview of recent advances in drug discovery targeting histone demethylases, focusing specifically on drug combination therapy and histone demethylases-targeting dual inhibitors. We discuss the rational design, pharmacodynamics, pharmacokinetics, and clinical status of these approaches. Additionally, we summarize the co-crystal structures of LSD1 inhibitors and their target proteins as well as describe the corresponding binding interactions. Finally, we also provided the challenges and future directions for utilizing histone demethylases in cancer therapy, such as PROTACs and molecular glue etc.

KDM4 Demethylases: Structure, Function, and Inhibitors

KDM4 histone demethylases mainly catalyze the removal of methyl marks from H3K9 and H3K36 to epigenetically regulate chromatin structure and gene expression. KDM4 expression is strictly regulated to ensure proper function in a myriad of biological processes, including transcription, cellular proliferation and differentiation, DNA damage repair, immune response, and stem cell self-renewal. Aberrant expression of KDM4 demethylase has been documented in many types of blood and solid tumors, and thus, KDM4s represent promising therapeutic targets. In this chapter, we summarize the current knowledge of the structures and regulatory mechanisms of KDM4 proteins and our understanding of their alterations in human pathological processes with a focus on development and cancer. We also review the reported KDM4 inhibitors and discuss their potential as therapeutic agents.

Recent Advances with KDM4 Inhibitors and Potential Applications

The histone lysine demethylase 4 (KDM4) family plays an important role in regulating gene transcription, DNA repair, and metabolism. The dysregulation of KDM4 functions is associated with many human disorders, including cancer, obesity, and cardiovascular diseases. Selective and potent KDM4 inhibitors may help not only to understand the role of KDM4 in these disorders but also to provide potential therapeutic opportunities. Here, we provide an overview of the field and discuss current status, challenges, and opportunities lying ahead in the development of KDM4-based anticancer therapeutics.

Targeting cancer epigenetic pathways with small-molecule compounds: Therapeutic efficacy and combination therapies

Epigenetics mainly refers to covalent modifications to DNA or histones without affecting genomes, which ultimately lead to phenotypic changes in cells or organisms. Given the abundance of regulatory targets in epigenetic pathways and their pivotal roles in tumorigenesis and drug resistance, the development of epigenetic drugs holds a great promise for the current cancer therapy. However, lack of potent, selective, and clinically tractable small-molecule compounds makes the strategy to target cancer epigenetic pathways still challenging. Therefore, this review focuses on epigenetic pathways, small molecule inhibitors targeting DNA methyltransferase (DNMT) and small molecule inhibitors targeting histone modification (the main regulatory targets are histone acetyltransferases (HAT), histone deacetylases (HDACs) and histone methyltransferases (HMTS)), as well as the combination strategies of the existing epigenetic therapeutic drugs and more new therapies to improve the efficacy, which will shed light on a new clue on discovery of more small-molecule drugs targeting cancer epigenetic pathways as promising strategies in the future.

Unravelling KDM4 histone demethylase inhibitors for cancer therapy

Epigenetic enzyme-targeted therapy is a promising new development in the field of drug discovery. To date, histone deacetylases and DNA methyltransferases have been investigated as druggable epigenetic enzyme targets in cancer therapeutics. Histone methyltransferases and lysine demethylase inhibitors are the latest groups of epi-drugs being actively studied in clinical trials. KDM4s are JmjC domain-containing histone H3 lysine 9/36 demethylase enzymes, belonging to the 2-OG-dependent oxygenases, which are upregulated in multiple malignancies. In the recent years, these enzymes have captured much attention as a novel target in cancer therapy. Herein, we traverse the discovery path and current challenges in designing potent KDM4 inhibitors as potential anticancer agents. We discuss the considerable efforts and proposed future strategies to develop selective small molecule inhibitors of KDM4s, highlighting scaffold candidates and cyclic skeletons for which activity data, selectivity profiles and structure-activity relationships (SARs) have been studied.

Dimethylamination of Primary Alcohols Using a Homogeneous Iridium Catalyst: A Synthetic Method for N,N-Dimethylamine Derivatives

A new catalytic system for N,N-dimethylamination of primary alcohols using aqueous dimethylamine in the absence of additional organic solvents has been developed. The reaction proceeds via borrowing hydrogen processes, which are atom-efficient and environmentally benign. An iridium catalyst bearing an N-heterocyclic carbene (NHC) ligand exhibited high performance, without showing any deactivation under aqueous conditions. In addition, valuable N,N-dimethylamine derivatives, including biologically active and pharmaceutical molecules, were synthesized. The practical application of this methodology was demonstrated by a gram-scale reaction.

Targeting histone demethylase KDM5B for cancer treatment

KDM5B (Lysine-Specific Demethylase 5B) erases the methyl group from H3K4me2/3, which performs wide regulatory effects on chromatin structure, and represses the transcriptional function of genes. KDM5B functions as an oncogene and associates with human cancers closely. Targeting KDM5B has been a promising direction for curing cancer since the emergence of potent KDM5B inhibitor CPI-455. In this area, most reported KDM5B inhibitors are Fe (Ⅱ) chelators, which also compete with the cofactor 2-OG in the active pockets. Besides, Some KDM5B inhibitors have been identified through high throughput screening or biochemical screening. In this reviewing article, we summarized the pioneering progress in KDM5B to provide a comprehensive realization, including crystal structure, transcriptional regulation function, cancer-related functions, development of inhibitors, and SAR studies. We hope to provide a comprehensive overview of KDM5B and the development of KDM5B inhibitors.