International Union of Basic and Clinical Pharmacology CXIII: Nuclear Receptor Superfamily-Update 2023

The NR superfamily comprises 48 transcription factors in humans that control a plethora of gene network programs involved in a wide range of physiologic processes. This review will summarize and discuss recent progress in NR biology and drug development derived from integrating various approaches, including biophysical techniques, structural studies, and translational investigation. We also highlight how defective NR signaling results in various diseases and disorders and how NRs can be targeted for therapeutic intervention via modulation via binding to synthetic lipophilic ligands. Furthermore, we also review recent studies that improved our understanding of NR structure and signaling. SIGNIFICANCE STATEMENT: Nuclear receptors (NRs) are ligand-regulated transcription factors that are critical regulators of myriad physiological processes. NRs serve as receptors for an array of drugs, and in this review, we provide an update on recent research into the roles of these drug targets.

A step-economical divergent approach to isoflavenes based on Suzuki-Miyaura cross coupling of a 3-boryl-2H-chromene with aryl bromides: application to total synthesis of isoflavonoid natural products

We present a step-economical divergent synthetic approach for isoflavene derivatives using the Suzuki-Miyaura cross coupling of a 3-boryl-2H-chromene and three aryl bromides. 3-Boryl-2H-chromene, which is not a well-explored species, was prepared via Miyaura-Ishiyama borylation of a 3-chloro-2H-chromene obtained through a Claisen rearrangement cyclization cascade reaction. Further conversion of the cross-coupling products, three isoflavene derivatives, afforded three isoflavonoid natural products with one or two additional reaction steps.

Estrogenic flavonoids and their molecular mechanisms of action

Flavonoids are a major group of phytoestrogens associated with physiological effects, and ecological and social impacts. Although the estrogenic activity of flavonoids was reported by researchers in the fields of medical, environmental and food studies, their molecular mechanisms of action have not been comprehensively reviewed. The estrogenic activity of the respective classes of flavonoids, anthocyanidins/anthocyanins, 2-arylbenzofurans/3-arylcoumarins/α-methyldeoxybenzoins, aurones/chalcones/dihydrochalcones, coumaronochromones, coumestans, flavans/flavan-3-ols/flavan-4-ols, flavanones/dihydroflavonols, flavones/flavonols, homoisoflavonoids, isoflavans, isoflavanones, isoflavenes, isoflavones, neoflavonoids, oligoflavonoids, pterocarpans/pterocarpenes, and rotenone/rotenoids, was summarized through a comprehensive literature search, and their structure-activity relationship, biological activities, signaling pathways, and applications were discussed. Although the respective classes of flavonoids contained at least one chemical mimicking estrogen, the mechanisms varied, such as those with estrogenic, anti-estrogenic, non-estrogenic, and biphasic activities, and additional activities through crosstalk/bypassing, which exert biological activities through cell signaling pathways. Such mechanistic variations of estrogen action are not limited to flavonoids and are observed among other broad categories of chemicals, thus this group of chemicals can be termed as the "estrogenome". This review article focuses on the connection of estrogen action mainly between the outer and the inner environments, which represent variations of chemicals and biological activities/signaling pathways, respectively, and form the basis to understand their applications. The applications of chemicals will markedly progress due to emerging technologies, such as artificial intelligence for precision medicine, which is also true of the study of the estrogenome including estrogenic flavonoids.

4-Dimethylaminopyridine (DMAP), A Superior Mediator for Morita-Balylis-Hillman Reaction-Triggered Annulative Condensation of Salicylaldehydes and Acrylonitrile to Form 3-Cyano-2H-chromenes

We unveiled superior base mediators for the annulative condensation of salicylaldehydes and acrylonitrile to give 3-cyano-2H-chromenes, which has been mediated only by 1,4-diazabicyclo[2.2.2]octane (DABCO) over the past two decades. The reactions were most efficiently mediated by 4-dimethylaminopyridine (DMAP), which yielded 3-cyano-2H-chromenes in higher yields than DABCO in most cases. We also confirmed that the reaction remained high yielding in a decagram-scale experiment with a catalytic amount of DMAP. The utility of this reaction was also exemplified by derivatization of an obtained 3-cyano-2H-chromene into a known 2H-chromene-3-carboxylic acid, which was previously synthesized with a non-readily available reagent.

Discovery of novel 2H-chromene-3-carbonyl derivatives as selective estrogen receptor degraders (SERDs): Design, synthesis and biological evaluation

Selective estrogen receptor degraders (SERDs) not only block ERα activity but degrade this receptor at the same time and are effective in relapsed ERα positive breast cancer patients who have accepted other endocrine therapies. Herein, through scaffold hopping of coumarin skeleton, a series of 2H-chromene-3-carbonyl-based SERDs with phenyl acrylic acid group as the side chain were designed and synthesized. Compound XH04 containing 7-hydroxy-2H-chromene-3-carbonyl skeleton exhibited the most potent activities in 2D (IC₅₀ = 0.8 μM) and 3D cells culture models (MCF-7) and had the best ERα binding affinity as well. Furthermore, the significant antiestrogen property of compound XH04 was confirmed by inhibiting the expression of progesterone receptor (PgR) mRNA in MCF-7 cells. On the other hand, the outgoing ERα degradation property of compound XH04 was qualitatively and quantificationally verified by immunofluorescence analysis and Western blot assay in MCF-7 cells. Besides, compound XH04 repressed the expression level of Ki67 in MCF-7 cells and induced the apoptosis increase of this tumor cells in a dose-dependent manner like approved-SERD fulvestrant (2), while compound XH04 exhibited better preliminary pharmacokinetics in human and rat liver microsomes in vitro and a lower LogD_7.4 value than fulvestrant. And further molecular docking study revealed that compound XH04 possessed a proverbial and typical binding model with ERα like other reported SERD. All these results confirmed that 7-hydroxy-2H-chromene-3-carbonyl structure could be a feasible skeleton for design of ERα antagonists including SERDs and compound XH04 is a promising candidate for further development of ERα + breast cancer therapy agents.

Access to Electron-Deficient 2,2-Disubstituted Chromanes: A Highly Regioselective One-Pot Synthesis via an Inverse-Electron-Demand [4 + 2] Cycloaddition of ortho-Quinone Methides

We report the one-pot synthesis of 2,2-disubstituted chromanes with electron-withdrawing substituents. This reaction provides a simple yet efficient route to a wide range of electron-deficient chromanes in high yield and excellent regioselectivity. The reaction of salicylaldehyde with 1,1-disubstituted ethylenes smoothly furnishes these electron-deficient chromanes, which can be further transformed into functionalized chromanes or chromene. For example, BW683C was effectively synthesized from 5-chlorosalicylaldehyde with 4-chlorostyrene in two steps in excellent yield. The present reaction thus provides versatile access to functionalized electron-deficient chromanes and chromenes and therefore constitutes a promising tool for the synthesis of biologically and photochemically active molecules.