Targeting the TGF-ß signaling pathway: an updated patent review (2021-present).

INTRODUCTION: The TGF-ß signaling pathway is a complex network that plays a crucial role in regulating essential biological functions and is implicated in the onset and progression of multiple diseases. This review highlights the recent advancements in developing inhibitors targeting the TGF-ß signaling pathway and their potential therapeutic applications in various diseases. AREA COVERED: The review discusses patents on active molecules related to the TGF-ß signaling pathway, focusing on three strategies: TGF-ß activity inhibition, blocking TGF-ß receptor binding, and disruption of the signaling pathway using small molecule inhibitors. Combination therapies and the development of fusion proteins targeting multiple pathways are also explored. The literature search was conducted using the Cortellis Drug Discovery Intelligence database, covering patents from 2021 onwards. EXPERT OPINION: The development of drugs targeting the TGF-ß signaling pathway has made significant progress in recent years. However, addressing challenges such as specificity, systemic toxicity, and patient selection is crucial for their successful clinical application. Targeting the TGF-ß signaling pathway holds promise as a promising approach for the treatment of various diseases.

Discovery of Covalent Lead Compounds Targeting 3CL Protease with a Lateral Interactions Spiking Neural Network.

Covalent drugs exhibit advantages in that noncovalent drugs cannot match, and covalent docking is an important method for screening covalent lead compounds. However, it is difficult for covalent docking to screen covalent compounds on a large scale because covalent docking requires determination of the covalent reaction type of the compound. Here, we propose to use deep learning of a lateral interactions spiking neural network to construct a covalent lead compound screening model to quickly screen covalent lead compounds. We used the 3CL protease (3CL Pro) of SARS-CoV-2 as the screen target and constructed two classification models based on LISNN to predict the covalent binding and inhibitory activity of compounds. The two classification models were trained on the covalent complex data set targeting cysteine (Cys) and the compound inhibitory activity data set targeting 3CL Pro, respected, with good prediction accuracy (ACC > 0.9). We then screened the screening compound library with 6 covalent binding screening models and 12 inhibitory activity screening models. We tested the inhibitory activity of the 32 compounds, and the best compound inhibited SARS-CoV-2 3CL Pro with an IC50 value of 369.5 nM. Further assay implied that dithiothreitol can affect the inhibitory activity of the compound to 3CL Pro, indicating that the compound may covalently bind 3CL Pro. The selectivity test showed that the compound had good target selectivity to 3CL Pro over cathepsin L. These correlation assays can prove the rationality of the covalent lead compound screening model. Finally, covalent docking was performed to demonstrate the binding conformation of the compound with 3CL Pro. The source code can be obtained from the GitHub repository (https://github.com/guzh970630/Screen_Covalent_Compound_by_LISNN).

Structure-Guided Design, Synthesis, and Antivirulence Assessment of Covalent Staphylococcus aureus Sortase A Inhibitors.

Sortase A (SrtA) is a membrane-associated cysteine transpeptidase required for bacterial virulence regulation and anchors surface proteins to cell wall, thereby assisting biofilm formation. SrtA is targeted in antivirulence treatments against Gram-positive bacterial infections. However, the development of potent small-molecule SrtA inhibitors is constrained owing to the limited understanding of the mode of action of inhibitors in the SrtA binding pocket. Herein, we designed and synthesized a novel class of covalent SrtA inhibitors based on the binding mode detailed in the X-ray crystal structure of the ML346/Streptococcus pyogenes SrtA complex. ML346 analog Y40 exhibited 2-fold increased inhibitory activity on Staphylococcus aureus SrtA and showed superior inhibitory effects on biofilm formation in vitro. Y40 protected Galleria mellonella larvae fromS. aureusinfections in vivo while minimally attenuating staphylococcal growth in vitro. Our study indicates that the covalent SrtA inhibitor Y40 is an antivirulence agent that is effective againstS. aureusinfections.

Discovery of a Novel, Potent, Orally Active, and Safe Inhibitor Targeting Human Mitochondrial RNA Polymerase.

High oxidative phosphorylation (OXPHOS) happens in some tumors, which depends on OXPHOS for energy supply, particularly in slow-cycling tumor cells. Therefore, targeting human mitochondrial RNA polymerase (POLRMT) to inhibit mitochondrial gene expression emerges as a potential therapeutic strategy to eradicate tumor cells. In this work, exploration and optimization of the first-in-class POLRMT inhibitor IMT1B and its SAR led to the identification of a novel compound D26, which exerted a strong antiproliferative effect on several cancer cells and decreased mitochondrial-related genes expression. In addition, mechanism studies demonstrated that D26 arrested cell cycle at the G1 phase and had no effect on apoptosis, depolarized mitochondria, or reactive oxidative stress generation in A2780 cells. Importantly, D26 exhibited more potent anticancer activity than the lead IMT1B in A2780 xenograft nude mice and had no observable toxic effect. All results suggest that D26 deserves to be further investigated as a potent and safe antitumor candidate.

New Set of Isobaric Labeling Reagents for Quantitative 16Plex Proteomics.

Peptide labeling by isobaric tags is a powerful approach for the relative quantitative analysis of proteomes in multiple groups. There has been a revolution in the innovation of new isobaric reagents; however, great effort is being made to expand simultaneous labeling groups to identify more labeled peptides and reduce reporter ion signal suppression. We redesigned the original chemical structure of the deuterium isobaric amine-reactive tag developed in our laboratory. We optimized the synthetic pathway to create a new set of 16-plex isobaric tags (IBT-16plex). The novel reagent enabled almost complete labeling of peptides within 90 min, with all labeling reporter ions exhibiting comparable MS/MS signals. Compared to a typical 16plex reagent, TMTpro-16plex, the peptides and proteins identified by IBT-16plex in trypsinized HeLa cells were significantly increased by 14.8 and 8.6%, respectively. Moreover, differences in peptide abundance within 10-fold among multiple groups were barely suppressed in IBT-16plex, whereas the dynamic range in TMTpro-16plex-labeled groups was smaller. After quantitative examination of MCF7 cell proteins, IBT-16plex was confirmed as feasible and useful for evaluating protein responses of glucose-starved MCF7 cells to a glucose-rich medium.

Design, Synthesis, and Biological Evaluation of Novel Chromanone Derivatives as Multifunctional Agents for the Treatment of Alzheimer's Disease.

Based on a multitarget strategy, a series of novel chromanone-1-benzyl-1,2,3,6-tetrahydropyridin hybrids were identified for the potential treatment of Alzheimer's disease (AD). Biological evaluation demonstrated that these hybrids exhibited significant inhibitory activities toward acetylcholinesterase (AChE) and monoamine oxidase B (MAO-B). The optimal compound C10 possessed excellent dual AChE/MAO-B inhibition both in terms of potency and equilibrium (AChE: IC50 = 0.58 ± 0.05 µM; MAO-B: IC50 = 0.41 ± 0.04 µM). Further molecular modeling and kinetic investigations revealed that compound C10 was a dual-binding inhibitor bound to both the catalytic anionic site and peripheral anionic site of AChE. In addition, compound C10 exhibited low neurotoxicity and potently inhibited AChE enzymatic activity. Furthermore, compound C10 more effectively protected against mitochondrial dysfunction and oxidation than donepezil, strongly inhibited AChE-induced amyloid aggregation, and moderately reduced glutaraldehyde-induced phosphorylation of tau protein in SH-SY5Y cells. Moreover, compound C10 displayed largely enhanced improvements in cognitive behaviors and spatial memory in a scopolamine-induced AD mice model with better efficacy than donepezil. Overall, the multifunctional profiles of compound C10 suggest that it deserves further investigation as a promising lead for the prospective treatment of AD.

Discovery of novel hybrids containing clioquinol-1-benzyl-1,2,3,6-tetrahydropyridine as multi-target-directed ligands (MTDLs) against Alzheimer's disease.

Based on the multitarget strategy, a series of novel clioquinol-1-benzyl-1,2,3,6-tetrahydropyridine hybrids were identified for the potential treatment of Alzheimer's disease (AD). Biological evaluation in vitro revealed that these hybrids exhibited significant inhibitory activities toward acetylcholinesterase (AChE). The optimal compound, 19n, exhibited excellent AChE inhibitory potency (IC50 = 0.11 µM), appropriate metal chelating functions, modulation of AChE- and metal-induced Aß aggregation, neuroprotection against okadaic acid-induced mitochondrial dysfunction and ROS damage, and interesting properties that reduced p-Tau levels in addition to no toxicity on SH-SY5Y cells observed at a concentration up to 50 µM. Most importantly, compound 19n was more well tolerated (>1200 mg/kg) than donepezil (LD50 = 28.124 mg/kg) in vivo. Moreover, compound 19n demonstrated marked improvements in cognitive and spatial memory in two AD mice models (scopolamine-induced and Aß1-42-induced) and suppressed inflammation induced by Aß1-42 in the cortex. The multifunctional profiles of compound 19n demonstrate that it deserves further investigation as a promising lead in the development of innovatively multifunctional drugs for Alzheimer's disease.

Identification of a Potent Oridonin Analogue for Treatment of Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is one of the most highly invasive and metastatic breast cancers without safe and effective therapeutic drugs. The natural product oridonin is reported to be a potential anti-TNBC agent. However, its moderate activity and complex structure hampered its clinical application. In this study, the novel oridonin analogues were first identified by removal of multiple hydroxyl groups and structural simplification of oridonin. The representative analogue 20 exhibited potent anticancer effects. Further structural modification on 20 generated the most potent derivative 56, which possessed 120-fold more potent antiproliferative activity than oridonin in the TNBC cell line HCC1806. Importantly, compound 56 exhibited more potent anticancer activity than paclitaxel in TNBC xenograft nude mice. Moreover, 56 could attenuate the expression of MMP-2, MMP-9, p-FAK, and integrin ß1 to inhibit TNBC cell metastasis. All results suggest that compound 56 may warrant further investigation as a promising candidate agent for the treatment of TNBC.

Author Correction: Novel 2-phenyloxypyrimidine derivative induces apoptosis and autophagy via inhibiting PI3K pathway and activating MAPK/ERK signaling in hepatocellular carcinoma cells.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Nickel-Catalyzed Reductive 1,2-Dialkynylation of Alkenes Bearing an 8-Aminoquinoline Directing Group.

An unprecedented nickel-catalyzed reductive 1,2-dialkynylation of alkenes bearing an 8-aminoquinoline directing group has been developed. This method proceeded through a migratory insertion/reductive-coupling process under mild conditions with a wide substrate scope and good functional group tolerance, providing direct access to the synthetically flexible 1,5-diynes. Moreover, the 1,2-dialkynylation products could be further converted to borate-ester- or azide-functionalized 1,5-dienes, ditriazole, ß-diyne primary amide, and trisubstituted benzene.

The Characteristics of PD-L1 Inhibitors, from Peptides to Small Molecules.

The programmed cell death ligand protein 1 (PD-L1) is a member of the B7 protein family and consists of 290 amino acid residues. The blockade of the PD-1/PD-L1 immune checkpoint pathway is effective in tumor treatment. Results: Two pharmacophore models were generated based on peptides and small molecules. Hypo 1A consists of one hydrogen bond donor, one hydrogen bond acceptor, two hydrophobic points and one aromatic ring point. Hypo 1B consists of one hydrogen bond donor, three hydrophobic points and one positive ionizable point. Conclusions: The pharmacophore model consisting of a hydrogen bond donor, hydrophobic points and a positive ionizable point may be helpful for designing small-molecule inhibitors targeting PD-L1.

Design, synthesis and biological evaluation of pyridine-chalcone derivatives as novel microtubule-destabilizing agents.

Further optimization of the trimethoxyphenyl scaffold of parent chalcone compound (2a) by introducing a pyridine ring afforded a series of novel pyridine-chalcone derivatives as potential anti-tubulin agents. All the target compounds were evaluated for their antiproliferative activities. Among them, representative compound 16f exhibited the most potent activity with the IC50 values ranging from 0.023 to 0.045 µM against a panel of cancer cell lines. Further mechanism study results demonstrated that compound 16f effectively inhibited the microtubule polymerization by binding to the colchicine site of tubulin. Moreover, cellular mechanism studies disclosed that 16f caused G2/M phase arrest, induced cell apoptosis and disrupted the intracellular microtubule network. Also, 16f reduced the cell migration and disrupted the capillary-like tube formation of human umbilical vein endothelial cells (HUVECs). Importantly, 16f significantly inhibited tumor growth in H22 xenograft models without apparent toxicity, which was stronger than the reference compound CA-4, indicating that it is worthy to investigate 16f as a potent microtubule-destabilizing agent for cancer therapy.

Characteristics of parathyroid hormone-1 receptor agonists and antagonists.

Aim: Parathyroid hormone-1 receptor (PTH1R) is a member of B G protein-coupled receptors. The agonistic activation of the PTH1R results in the production and secretion of osteoclast-stimulating cytokines while antagonists may be used to treat bone metastases, hypercalcemia, cachexia and hyperparathyroidism. Results: We built pharmacophore models and investigated the characteristics of PTH1R agonists and antagonists. The agonist model consists of three hydrophobic points, one hydrogen bond acceptor and one positive ionizable point. The antagonist model consists of one hydrogen bond donor and three hydrophobic points. Conclusion: The features of the two models are similar, but the hydrogen bond acceptor, which is the main difference between PTH1R agonists and antagonists, suggests it may be essential for the agonist.

Discovery of trans-3-(pyridin-3-yl)acrylamide-derived sulfamides as potent nicotinamide phosphoribosyltransferase (NAMPT) inhibitors for the potential treatment of cancer.

Nicotinamide phosphoribosyltransferase (NAMPT) has emerged as a promising target for the discovery of anticancer drugs. Based on NAMPT inhibitor FK866 that has been advanced into phase II trial, we identified a trans-3-(pyridin-3-yl)acrylamide compound 13 incorporating with a biarylsulfanilamide moiety as a new NAMPT inhibitor. Further structure-activity relationship (SAR) exploration led to additional biarylsulfanilamide-derived compounds with high in vitro NAMPT inhibitory potency and antiproliferative activity. In particular, compound 23, the most potent NAMPT inhibitor (IC50 = 5.08 nM), showed single-digit nanomolar antiproliferative activity against DU145, Hela, and H1975 cells with IC50 values of 2.90 nM, 2.34 nM, and 2.24 nM, respectively, and even subnanomolar level against K562, MCF-7, and HUH7 cells with IC50 values of 0.46 nM, 0.23 nM and 0.53 nM, respectively. Our findings provided promising lead compounds for the discovery of more potent NAMPT inhibitors as anticancer drugs.

Macrocyclization of peptidoarylacetamides with self-assembly properties through late-stage palladium-catalyzed C(sp2)▬H olefination.

Peptide macrocycles often display diverse bioactivities and self-assembly properties, which lead to a variety of applications in medicinal and material sciences. Transition metal-catalyzed C▬H activations are emerging strategies for site-selective functionalization of amino acids and peptides, as well as the construction of cyclic peptides. Here, we report the development of a peptide-directed method for the macrocyclization of peptidoarylacetamides by Pd(II)-catalyzed late-stage C(sp2)▬H olefination. In this protocol, peptide backbones act as internal directing groups and enable facile preparation of diverse cyclic peptides that are difficult to synthesize by conventional macrolactamization. Furthermore, we show that the incorporation of aryl-alkene cross-link in the backbone constrains cyclic peptides into conformations for self-assembly.

Design, synthesis, and biological evaluation of truncated deguelin derivatives as Hsp90 inhibitors.

A series of novel B and C-rings truncated deguelin derivatives have been designed and synthesized in the present study as heat shock protein 90 (Hsp90) inhibitors. The synthesized compounds exhibited micromolar antiproliferative potency toward a panel of human cancer cell lines. Their structure-activity relationships (SARs) were investigated in a systematic manner. Compound 21c was identified to have high Hsp90 binding potency (60 nM) and caused degradation of client proteins through ubiquitin proteasome system. Further biological studies showed that compound 21c induced a dose-dependent S and G2-phase cell cycle arrest on human breast cancer MCF-7 cells. Flow cytometry and Western blot analyses confirmed that compound 21c caused apoptosis of MCF-7 cells. In addition, compound 21c showed much potent inhibition on the migration and invasion of MCF-7 cells. Taken together, these results suggest that 21c might be a promising lead compound for further development of Hsp90 inhibitors.

Synthesis, molecular properties prediction and biological evaluation of indole-vinyl sulfone derivatives as novel tubulin polymerization inhibitors targeting the colchicine binding site.

Twenty-two novel indole-vinyl sulfone derivatives were designed, synthesized and evaluated as tubulin polymerization inhibitors. The physicochemical and drug-likeness properties of all target compounds were predicted by Osiris calculations. All compounds were evaluated for their antiproliferative activities, among them, compound 7f exhibited the most potent activity against a panel of cancer cell lines, which was 2-7 folds more potent than our previously reported compound 4. Especially, 7f displayed about 8-fold improvement of selective index as compared with compound 4, indicating that 7f might have lower toxicity. Besides, 7f inhibited the microtubule polymerization by binding to the colchicine site of tubulin. Further investigations showed that compound 7f effectively disrupted microtubule network, caused cell cycle arrest at G2/M phase and induced cell apoptosis in K562 cells. Moreover, 7f reduced the cell migration and disrupted capillary-like tube formation in HUVEC cells. Importantly, the in vivo anti-tumor activity of 7f was validated in H22 liver cancer xenograft mouse model without apparent toxicity, suggesting that 7f is a promising anti-tubulin agent for cancer therapy.

Discovery of Novel Quinoline-Chalcone Derivatives as Potent Antitumor Agents with Microtubule Polymerization Inhibitory Activity.

A series of novel quinoline-chalcone derivatives were designed, synthesized, and evaluated for their antiproliferative activity. Among them, compound 24d exhibited the most potent activity with IC50 values ranging from 0.009 to 0.016 µM in a panel of cancer cell lines. Compound 24d also displayed a good safety profile with an LD50 value of 665.62 mg/kg by intravenous injection, and its hydrochloride salt 24d-HCl significantly inhibited tumor growth in H22 xenograft models without observable toxic effects, which was more potent than that of CA-4. Mechanism studies demonstrated that 24d bound to the colchicine site of tubulin, arrested the cell cycle at the G2/M phase, induced apoptosis, depolarized mitochondria, and induced reactive oxidative stress generation in K562 cells. Moreover, 24d has potent in vitro antimetastasis and in vitro and in vivo antivascular activities. Collectively, our findings suggest that 24d deserves to be further investigated as a potent and safe antitumor agent for cancer therapy.

Design, synthesis and biological evaluation of quinoline-indole derivatives as anti-tubulin agents targeting the colchicine binding site.

A series of novel isocombretastatin A-4 (isoCA-4) analogs were designed and synthesized by replacing 3,4,5-trimethoylphenyl and isovanillin of isoCA-4 with quinoline and indole moieties, respectively. The structure activity relationships (SARs) of these synthesized quinoline-indole derivatives have been intensively investigated. Two compounds 27c and 34b exhibited the most potent activities against five cancer cell lines with IC50 values ranging from 2 to 11 nM, which were comparable to those of Combretastatin A-4 (CA-4, 1). Further mechanism investigations revealed that 34b effectively inhibited the microtubule polymerization by binding to the colchicine site of tubulin. Further cellular mechanism studies elucidated that 34b disrupted cell microtubule networks, arrested the cell cycle at G2/M phase, induced apoptosis and depolarized mitochondria of K562 cells. Moreover, 34b displayed potent anti-vascular activity in both wound healing and tube formation assays. Importantly, 27c and 34b significantly inhibited tumor growth in H22 xenograft models without apparent toxicity, suggesting that 27c and 34b deserve further research as potent antitumor agents for cancer therapy.

Synthesis, Biological Evaluation of Fluorescent 23-Hydroxybetulinic Acid Probes, and Their Cellular Localization Studies.

23-Hydroxybetulinic acid (23-HBA) is a complex lupane triterpenoid, which has attracted increasing attention as an anticancer agent. However, its detailed mechanism of anticancer action remains elusive so far. To reveal its anticancer mode of action, a series of fluorescent 23-HBA derivatives conjugated with coumarin dyes were designed, synthesized, and evaluated for their antiproliferative activities. Subcellular localization and uptake profile studies of representative fluorescent 23-HBA probe 26c were performed in B16F10 cells, and the results suggested that probe 26c was rapidly taken up into B10F10 cells in a dose-dependent manner and mitochondrion was the main site of its accumulation. Further mode of action studies implied that the mitochondrial pathway was involved in 23-HBA-mediated apoptosis. Together, our results provided new clues for revealing the molecular mechanism of natural product 23-HBA for its further development into an antitumor agent.