Brazilian Organic Honeydew Reduces In Vitro and In Vivo Periodontal Disease-Related Subgingival Biofilm

We investigated the antimicrobial properties and effects on bone resorption of Brazilian organic honeydew (OHD) from the Bracatinga tree (Mimosa scabrella Benth.), a rare honey certified with Denomination of Origin, using a periodontal disease model. Antibiofilm activity was assessed using a subgingival biofilm adhered to the Calgary device. Biofilms were treated with OHD, chlorhexidine (0.12%), or a vehicle twice daily for 1 min starting on day 3, at concentrations of 2× and 10× the minimum inhibitory concentration (MIC). We employed a ligature-induced chronic periodontal disease model and challenged it with Porphyromonas gingivalis in C57BL/6 mice. The chemical profile of OHD was analyzed using LC-ESI-IT-MS/MS. Results were evaluated by measuring bone loss and microbial composition of the ligature biofilm through DNA-DNA hybridization. OHD demonstrated significant activity against P. gingivalis (MIC 4%, MBC 6%) and reduced biofilm viability by 80% in vitro. In vivo, OHD decreased microbial populations and decreased bone loss associated with periodontal disease. Chemical analysis identified seven compounds in OHD, including five flavonoids and two lignans. This Brazilian honeydew from the Atlantic Forest exhibits strong antimicrobial properties and potential as a functional food for oral health, offering a promising alternative for the control and prevention of periodontal disease.

Post-translational modifications of immune checkpoints: unlocking new potentials in cancer immunotherapy

Immunotherapy targeting immune checkpoints has gained traction across various cancer types in clinical settings due to its notable advantages. Despite this, the overall response rates among patients remain modest, alongside issues of drug resistance and adverse effects. Hence, there is a pressing need to enhance immune checkpoint blockade (ICB) therapies. Post-translational modifications (PTMs) are crucial for protein functionality. Recent research emphasizes their pivotal role in immune checkpoint regulation, directly impacting the expression and function of these key proteins. This review delves into the influence of significant PTMs-ubiquitination, phosphorylation, and glycosylation-on immune checkpoint signaling. By targeting these modifications, novel immunotherapeutic strategies have emerged, paving the way for advancements in optimizing immune checkpoint blockade therapies in the future.

High-Throughput Repurposing Screen Reveals Compounds with Activity against Toxoplasma gondii Bradyzoites

Toxoplasma gondii causes widespread chronic infections that are not cured by current treatments due to the inability to affect semidormant bradyzoite stages within tissue cysts. To identify compounds to eliminate chronic infection, we developed an HTS using a recently characterized strain of T. gondii that undergoes efficient conversion to bradyzoites in vitro. Stage-specific expression of luciferase was used to selectively monitor the growth inhibition of bradyzoites by the Library of Pharmacological Active Compounds, consisting of 1280 drug-like compounds. We identified 44 compounds with >50% inhibitory effects against bradyzoites, including new highly potent compounds, several of which have precedent for antimicrobial activity. Subsequent characterization of the compound sanguinarine sulfate revealed potent and rapid killing against in vitro-produced bradyzoites and bradyzoites harvested from chronically infected mice, including potent activity against intact cysts. These findings provide a platform for expanded screening and identify promising compounds for further preclinical development against T. gondii bradyzoites that are responsible for chronic infection.

Is a Fungal Apocalypse Inevitable or Just a Hallucination? An Overview of the Antifungal Armamentarium Used in the Fight against Pathogenic Fungi

The World Health Organization (WHO) fungal priority pathogens list (WHO FPPL) published in 2022 highlighted the inequity and research challenges faced by researchers who study pathogenic fungi that afflict humans. Antifungal drugs are the only weapon available to treat infections; however, these drugs are old, are not effective against multidrug-resistant (MDR) fungal strains, and are associated with substantial toxicity in clinical use. This Microperspective summarizes challenges pertaining to antifungal drug discovery in addition to highlighting recent advances and antifungal agents in clinical trials.

Immune checkpoint blockade for cancer therapy: current progress and perspectives

Dysfunction of anti-tumor immune responses is crucial for cancer progression. Immune checkpoint blockade (ICB), which can potentiate T cell responses, is an effective strategy for the normalization of host anti-tumor immunity. In recent years, immune checkpoints, expressed on both tumor cells and immune cells, have been identified; some of them have exhibited potential druggability and have been approved by the US Food and Drug Administration (FDA) for clinical treatment. However, limited responses and immune-related adverse events (irAEs) cannot be ignored. This review outlines the development and applications of ICBs, potential strategies for overcoming resistance, and future directions for ICB-based cancer immunotherapy.

Development of Potent SHP2 Allosteric Inhibitors: Design, Synthesis, and Evaluation with Antitumor Effects

Src homology-2-containing protein tyrosine phosphatase (PTP) 2 (SHP2) is a pivotal PTP that modulates key cellular processes including proliferation, differentiation, and migration. Its overexpression is implicated in the pathogenesis of various malignancies, highlighting the need for effective SHP2 inhibitors. Herein, we report the design and synthesis of a novel series of thiazolo[5,4-b]pyridine and imidazo[1,2-c]pyrimidine derivatives as SHP2 allosteric inhibitors identified through active fragment splicing. The synthesized compounds exhibited potent SHP2 inhibition, with IC50 values ranging from 9.0 to 34.5 nM. Notably, compound B8 demonstrated superior potency, with an IC50 of 0.04 μM for p-ERK modulation. Compound B8 also displayed favorable drug-like properties and significant antitumor activity in a KYSE520 xenograft mouse model, underscoring its potential as a lead candidate for further development. Our findings provide a foundation for the advancement of SHP2-targeted therapeutics.

The Endo-GeneScreen Platform Identifies Drug-Like Probes that Regulate Endogenous Protein Levels within Physiological Contexts

Traditional phenotypic drug discovery platforms have suffered from poor scalability and a lack of mechanistic understanding of newly discovered phenotypic probes. To address this, we created Endo- GeneScreen (EGS), a high-throughput enabled screening platform that identifies bioactive small molecules capable of regulating endogenous protein expression encoded by any preselected target gene within a biologically appropriate context. As a proof-of-concept, EGS successfully identified drug candidates that up-regulate endogenous expression of neuronal Syngap1, a gene that causes a neurodevelopmental disorder when haploinsufficient. For example, SR-1815, a previously unknown and undescribed kinase inhibitor, alleviated major cellular consequences of Syngap1 loss-of-function by restoring normal SynGAP protein levels and dampening neuronal hyperactivity within haploinsufficient neurons. Moreover, we demonstrate that EGS assays accelerate preclinical development of identified drug candidates and facilitate mode-of-action deconvolution studies. Thus, EGS identifies first-in-class bioactive small molecule probes that promote biological discovery and precision therapeutic development.

Discovery of Potent and Selective MNK Kinase Inhibitors for the Treatment of Leukemia

MNK activity is regulated by the p38 and Erk MAPK pathways. Phosphorylation of MNK leads to its activation and binding to the eIF4G/eIF4E complex. MNK then phosphorylates eIF4E at Ser209, whose activation is associated with oncogene translation, leading to tumorigenesis. Given this important role for eIF4E in tumorigenesis, MNK inhibition with novel small molecule inhibitors could be a promising strategy to combat AML, which continues to be an area of unmet medical need. Here, we report the medicinal optimization of a series of novel inhibitors and their evaluation of their effects on eIF4E and leukemia cell viability. We discovered a class of ether-containing compounds with a high MNK1/2 selectivity. These MNK inhibitors show good potency in reducing cell viability and colony formation and have desirable pharmacokinetic properties. X-ray cocrystallization was accomplished to confirm the binding mode of our inhibitors and aid in future optimization.

Recent Progress of Triplex DNA Formation and Its Applications

Recently, much attention has been focused on oligonucleotide drugs that precisely control the gene expression. Among these, triplex-forming oligonucleotides (TFOs) represent common antigene strategies because they bind specifically to the major groove position of genomic DNA to form a triplex DNA structure. Thus far, this promising triplex formation technique represents a successful strategy with strong application prospects for gene manipulation applications (e.g., cancer, Huntington's disease, inflammatory disease, etc.), analytical detection (e.g., nucleic acid, small molecules, etc.), and nanotechnology (e.g., molecular machines, etc.). This review summarizes in detail the full range of potential applications described above, particularly the various chemical modification strategies that have facilitated the stepwise advancement of TFO-based oligonucleotide drugs in recent years to improve the effectiveness, specificity, and applicability of triplex DNA and synergistically promote the effectiveness of triplex DNA.

Dynamic optimization elucidates higher-level pathogenicity strategies of Pseudomonas aeruginosa

Multiple dangerous pathogens from the World Health Organization's priority list possess a plethora of virulence components, including the ability to survive inside macrophages. Often, the pathogens rely on a multi-layered defence strategy in order to defend themselves against the immune system. Here, a minimal model is proposed to study such a strategy. By way of example, we consider the interaction between Pseudomonas aeruginosa and the human host, in which the host and the pathogen counter each other in a back-and-forth interaction. In particular, the pathogen attacks the host, macrophages of the host engulf the pathogen and reduce its access to glucose, the pathogen activates the glyoxylate shunt, which is started by the enzyme isocitrate lyase (Icl), the host inhibits it by itaconic acid, and the pathogen metabolizes itaconic acid using the enzyme succinyl-CoA:itaconate CoA transferase (Ict). The flux through the glyoxylate shunt allows the pathogen to avoid carbon loss and oxidative stress. These functions are of utmost importance inside a phagolysosome. Therefore, the pathogen needs to allocate its limited protein resource between the enzymes Icl and Ict in order to maximize the time integral of a flux through the enzyme Icl. We use both random search and dynamic optimization to identify the enzyme Ict as a cost-effective means of counter-counter-counter-defence and as a possible drug target during the early phase of infection.

Valproic Acid Improves Antisense-Mediated Exon-Skipping Efficacy in mdx Mice

Duchenne muscular dystrophy (DMD) is a severe genetic disorder characterized by the progressive degeneration of skeletal and cardiac muscles due to the absence of dystrophin. Exon-skipping therapy is among the most promising approaches for treating DMD, with several antisense oligonucleotides (ASO) already approved by the FDA; however, their limited efficacy highlights substantial potential for further improvement. In this study, we evaluate the potential of combining ASO with valproic acid (VPA) to enhance dystrophin expression and improve functional outcomes in a murine model of DMD. Our results indicate that the ASO+VPA treatment significantly increases dystrophin restoration across various muscle tissues, with particularly pronounced effects observed in cardiac muscle, where levels are nearly doubled compared to ASO monotherapy. Additionally, we demonstrate significant improvements in functional outcomes in treated mdx mice. Our findings suggest that the combined ASO+VPA therapy holds promise as an effective therapeutic approach to ameliorate muscle function in DMD, warranting further exploration of its mechanistic pathways and long-term benefits.

Nanoenabling MbtI Inhibitors for Next-Generation Tuberculosis Therapy

The urgent need for safer and innovative antitubercular agents remains a priority for the scientific community. In pursuit of this goal, we designed and evaluated novel 5-phenylfuran-2-carboxylic acid derivatives targeting Mycobacterium tuberculosis (Mtb) salicylate synthase (MbtI), a key enzyme, absent in humans, that plays a crucial role in Mtb virulence. Several potent MbtI inhibitors demonstrating significant antitubercular activity and a favorable safety profile were identified. Structure-guided optimization yielded 5-(3-cyano-5-isobutoxyphenyl)furan-2-carboxylic acid (1e), which exhibited strong MbtI inhibition (IC50 = 11.2 μM) and a promising in vitro antitubercular activity (MIC99 = 32 μM against M. bovis BCG). Esters of 1e were effectively loaded into poly(2-methacryloyloxyethyl phosphorylcholine)-poly(2-(diisopropylamino)ethyl methacrylate) (PMPC-PDPA) polymersomes (POs) and delivered to intracellular mycobacteria, resulting in reduced Mtb viability. This study provides a foundation for the use of POs in the development of future MbtI-targeted therapies for tuberculosis.

Systematic Determination of the Impact of Structural Edits on Peptide Accumulation into Mycobacteria

Understanding the factors that influence the accumulation of molecules beyond the mycomembrane of Mycobacterium tuberculosis ( Mtb ) - the main barrier to accumulation - is essential for developing effective antimycobacterial agents. In this study, we investigated two design principles commonly observed in natural products and mammalian cell-permeable peptides: backbone N -alkylation and macrocyclization. To assess how these structural edits impact molecule accumulation beyond the mycomembrane, we utilized our recently developed Peptidoglycan Accessibility Click-Mediated Assessment (PAC-MAN) assay for live-cell analysis. Our findings provide the first empirical evidence that peptide macrocyclization generally enhances accumulation in mycobacteria, while N -alkylation influences accumulation in a context-dependent manner. We examined these design principles in the context of two peptide antibiotics, tridecaptin A1 and griselimycin, which revealed the roles of N -alkylation and macrocyclization in improving both accumulation and antimicrobial activity against mycobacteria in specific contexts. Together, we present a working model for strategic structural modifications aimed at enhancing the accumulation of molecules past the mycomembrane. More broadly, our results also challenge the prevailing belief in the field that large and hydrophilic molecules, such as peptides, cannot readily traverse the mycomembrane.

Advances in the structures, mechanisms and targeting of molecular chaperones

Molecular chaperones, a class of complex client regulatory systems, play significant roles in the prevention of protein misfolding and abnormal aggregation, the modulation of protein homeostasis, and the protection of cells from damage under constantly changing environmental conditions. As the understanding of the biological mechanisms of molecular chaperones has increased, their link with the occurrence and progression of disease has suggested that these proteins are promising targets for therapeutic intervention, drawing intensive interest. Here, we review recent advances in determining the structures of molecular chaperones and heat shock protein 90 (HSP90) chaperone system complexes. We also describe the features of molecular chaperones and shed light on the complicated regulatory mechanism that operates through interactions with various co-chaperones in molecular chaperone cycles. In addition, how molecular chaperones affect diseases by regulating pathogenic proteins has been thoroughly analyzed. Furthermore, we focus on molecular chaperones to systematically discuss recent clinical advances and various drug design strategies in the preclinical stage. Recent studies have identified a variety of novel regulatory strategies targeting molecular chaperone systems with compounds that act through different mechanisms from those of traditional inhibitors. Therefore, as more novel design strategies are developed, targeting molecular chaperones will significantly contribute to the discovery of new potential drugs.

Fluorescent labeling strategies for molecular bioimaging

Super-resolution microscopy (SRM) has transformed biological imaging by circumventing the diffraction limit of light and enabling the visualization of cellular structures and processes at the molecular level. Central to the capabilities of SRM is fluorescent labeling, which ensures the precise attachment of fluorophores to biomolecules and has direct impact on the accuracy and resolution of imaging. Continuous innovation and optimization in fluorescent labeling are essential for the successful application of SRM in cutting-edge biological research. In this review, we discuss recent advances in fluorescent labeling strategies for molecular bioimaging, with a special focus on protein labeling. We compare different approaches, highlight technological breakthroughs, and address challenges such as linkage error and labeling density. By evaluating both established and emerging methods, we aim to guide researchers through all aspects that should be considered before opting for any labeling technique.

Molecules Targeting EriCF1 Increase Streptococcus mutans Fluoride Sensitivity

Dental caries, as one of the prevalent oral infectious diseases worldwide, constitutes a considerable disease burden. Fluoride has been widely used to prevent dental caries for decades. However, fluoride alone may not always be sufficient. The major cariogenic bacterial species, Streptococcus mutans, has not been effectively controlled by daily fluoride exposure, possibly because it has a detoxification mechanism. Studies have shown that most microorganisms have fluoride exporters dedicated to exporting fluoride ions (F-). S. mutans possesses 2 homologous genes, eriCF1 and eriCF2, which encode fluoride exporters, but their function has not been fully clarified. In this work, we constructed the markerless gene deletion mutants, overexpression, and complemented strains of S. mutans UA159. Assessing fluoride sensitivity, intracellular F- levels, and cell membrane permeability revealed that EriCF1 was the major functional unit of the fluoride exporter in S. mutans. To further enhance the antibacterial efficiency of fluoride, we identified 3 diphenylurea derivatives that might target EriCF1 by molecular docking, which significantly enhanced the antibacterial effect of sodium fluoride (NaF) by synergistically impeding fluoride efflux, as demonstrated by chequerboard broth microdilution assays. Moreover, these compounds combined with 1 mM NaF impaired the cariogenicity of S. mutans significantly in vivo and with good biocompatibility, especially compounds 9 and 15. Collectively, these findings suggest that fluoride exporters in S. mutans could serve as a potential target for caries prevention, and the diphenylurea derivatives identified for targeting EriCF1 could be a valuable therapeutic approach when combined with fluoride, providing promising measures for dental caries prevention.

An integrated structural and biophysical approach to study carbon metabolism in Mycobacterium tuberculosis

Metabolic enzymes are the catalysts that drive the biochemical reactions essential for sustaining life. Many of these enzymes are tightly regulated by feedback mechanisms. To fully understand their roles and modulation, it is crucial to investigate the relationship between their structure, catalytic mechanism, and function. In this perspective, by using three examples from our studies on Mycobacterium tuberculosis (Mtb) isocitrate lyase and related proteins, we highlight how an integrated approach combining structural, activity, and biophysical data provides insights into their biological functions. These examples underscore the importance of employing fast-fail experiments at the early stages of a research project, emphasise the value of complementary techniques in validating findings, and demonstrate how in vitro data combined with chemical, biochemical, and physiological knowledge can lead to a broader understanding of metabolic adaptations in pathogenic bacteria. Finally, we address the unexplored questions in Mtb metabolism and discuss how we expand our approach to include microbiological and bioanalytical techniques to further our understanding. Such an integrated and interdisciplinary strategy has the potential to uncover novel regulatory mechanisms and identify new therapeutic opportunities for the eradication of tuberculosis. The approach can also be broadly applied to investigate other biochemical networks and complex biological systems.

The Cation-π Interaction in Chemistry and Biology

The cation-π interaction is an important noncovalent binding force that impacts all areas of chemistry and biology. Extensive computational and gas phase experimental studies have established the potential strength and the essential nature of the interaction. Previous reviews have emphasized studies of model systems and a variety of biological examples. This work includes discussion of those areas but emphasizes other areas that are perhaps less well appreciated. These include the novel cation-π binding ability of alkali metals in water; the application of the cation-π interaction to organic synthesis and chemical biology; cooperative behaviors of multiple cation-π interactions, including adhesive proteins from mussels and similar organisms and the formation and modulation of biomolecular condensates (phase separation); and cation-π interactions involved in recognizing DNA/RNA.

Unlocking the potential of organopalladium complexes for high-grade serous ovarian cancer therapy

High-Grade Serous Ovarian Cancer (HGSOC) is the most common and lethal subtype of ovarian cancer, known for its high aggressiveness and extensive genomic alterations. Typically diagnosed at an advanced stage, HGSOC presents formidable challenges in drug therapy. The limited efficacy of standard treatments, development of chemoresistance, scarcity of targeted therapies, and significant tumor heterogeneity render this disease incurable with current treatment options, highlighting the urgent need for novel therapeutic approaches to improve patient outcomes. In this study we report a straightforward and stereoselective synthetic route to novel Pd(II)-vinyl and -butadienyl complexes bearing a wide range of monodentate and bidentate ligands. Most of the synthesized complexes exhibited good to excellent in vitro anticancer activity against ovarian cancer cells. Particularly promising is the water-soluble complex bearing two PTA (1,3,5-triaza-7-phosphaadamantane) ligands and the Pd(II)-butadienyl fragment. This compound combines excellent cytotoxicity towards cancer cells with substantial inactivity towards non-cancerous ones. This derivative was selected for further studies on ex vivo tumor organoids and in vivo mouse models, which demonstrate its remarkable efficacy with surprisingly low collateral toxicity even at high dosages. Moreover, this class of compounds appears to operate through a ferroptotic mechanism, thus representing the first such example for an organopalladium compound.

Conceptual expansion of photomedicine for spatiotemporal treatment methods

Photomedicine has evolved from basic phototherapy to a broad range of light-based technologies to achieve precise and minimally invasive therapeutic outcomes. Recent advances in light sources, photochemical reactions, and photoswitches have facilitated the development of light-activated methodologies for modulating biological processes. This review discusses the history of light therapy that leads to the emergence of a new field known as photopharmacology, mode of actions in photopharmacology such as photodynamic, photo-uncaging and photoswitchable methods, a few representative examples in photopharmacology, and a brief overview of its associated challenges. The current developments in photopharmacology hold great promise for the treatment of diseases such as cancer, with enhanced therapeutic precision, and minimal side effects. We foresee further expansion of photomedicine for novel approaches in precision medicine and healthcare, and unprecedented treatment methods.

Monitoring of Propiolamide-Mediated Molecular Crosstalk between Ferroptosis and Apoptosis by Raman Spectroscopy

Inducing programmed cell death is an efficient strategy for cancer treatments, and a deep understanding of the molecular mechanisms underlying cell death pathways is of significance for the rational design of anticancer drugs. Herein, propiolamide-mediated crosstalk between ferroptosis and apoptosis is investigated. In situ monitoring of reactive oxygen species (ROS) formation and the structural changes of propiolamide compounds is achieved by Raman spectroscopy. The molecular mechanisms of propiolamides in inducing monooxygenase-mediated ROS generation and inhibiting GPX4 activities are revealed. Furthermore, the pro-ferroptotic and pro-apoptotic roles of the propiolamides containing terminal alkynes are verified. This study provides an in situ and label-free strategy for monitoring enzyme-drug interactions and their dynamics. It is a first attempt to study the structural basis of molecular crosstalk through two important enzymes in cell death. This study paves the way for designing novel drugs that are capable of triggering a synergistic contribution of multiple cell death forms to anticancer efficacy.

Fifteen years of ChEMBL and its role in cheminformatics and drug discovery

In October 2024 we celebrated the 15th anniversary of the first launch of ChEMBL, Europe's most impactful, open-access drug discovery database, hosted by EMBL's European Bioinformatics Institute (EMBL-EBI). This is a good moment to reflect on ChEMBL's history, the role that ChEMBL plays in Cheminformatics and Drug Discovery as well as innovations accelerated using data extracted from it. The review closes by discussing current challenges and possible directions that need to be taken to guarantee that ChEMBL continues to be the pioneering resource for highly curated, open bioactivity data on the European continent and beyond.

The role of PTP1B in cardiometabolic disorders and endothelial dysfunction

Cardiovascular diseases (CVD) are a global health concern that accounts for a large share of annual mortality. Endothelial dysfunction is the main underlying factor that eventually leads to cardiovascular events. Recent studies have underscored the critical function of Protein Tyrosine Phosphatase 1B (PTP1B) in the onset of endothelial dysfunction, chiefly through its involvement in metabolic diseases such as diabetes, obesity, and leptin resistance. PTP1B attenuates insulin and leptin signalling by dephosphorylating their respective receptors at key tyrosine residues, resulting in resistance-both of which are significant mechanisms underpinning the development of endothelial dysfunction. PTP1B also contributes to the disruption of the endoplasmic reticulum, causing endoplasmic reticulum stress, another molecular driver of endothelial dysfunction. Efforts to inhibit PTP1B activity hold the promise of advancing the prevention and management of CVD and metabolic disorders, as these conditions share common risk factors and underlying cellular mechanisms. Numerous small molecules have been reported as PTP1B inhibitors; however, their progression to advanced clinical trials has been hindered by major challenges such as low selectivity and undesirable side effects. This review provides an in-depth analysis of PTP1B's involvement in metabolic diseases and its interaction with CVD and examines the strategies and challenges related to inhibiting this enzyme.

Pyrazolopyrimidines: A Promising Frontier in Cancer Treatment-Reviewing Their Potential as Inhibitors of Serine/Threonine Kinases

Pyrazolopyrimidine derivatives have emerged as potent inhibitors targeting a broad spectrum of kinases, particularly serine/threonine kinases (STK). This review provides a comprehensive overview of the structural modifications and pharmacological relevance of pyrazolopyrimidine compounds in the realm of kinase inhibition. Specifically, the focus is placed on their inhibitory action against STK, key players in cell signaling and potential therapeutic targets in various diseases, especially cancer. The structure-activity relationship (SAR) of these derivatives highlights the importance of specific substituents in enhancing inhibitory activity, and pyrazolopyrimidine derivatives have shown promising inhibitory activity against certain STK. Challenges remain, including issues related to drug resistance, off-target effects, and potential toxicity. Future research is geared toward designing more selective derivatives with improved pharmacokinetic properties and reduced side effects.

Exploring USFDA-Approved Imidazole-Based Small Molecules in Drug Discovery: A Mini Perspective

In the present work, we have explored the importance of the imidazole ring and its importance in drug discovery, citing the key approvals in the present decade (2013-2024). The pharmacological attribution for the approved drugs revealed that out of 20 approved drugs, 45% of the approvals were made as anti-infectives, followed by approvals under the category of genetic and metabolic disorders, sexual endocrine disorders, anticancer, and to treat blood pressure, gastrointestinal disorders, and neurological conditions. Most approved drugs were dispensed through solid dosage forms (13) and thus had predominantly oral routes beside others. The metabolism pattern revealed that the drugs undergo metabolism via the involvement of multiple enzymes, where CYP3A4 and CYP3A5 were the core enzymes. The excretion pattern of these drugs revealed that the drugs are majorly excreted via the fecal route. The chemical analysis showed that pyrrolidine/pyrrole was the major heterocycle in the approved drugs, followed by the indole ring in the hybridization. Considering the substitution pattern, most drugs possessed amide, amines, and fluoro group as the functional substitution with the 2,4-substitution pattern seen in most approved drugs. Besides this, the three approved drugs were found to possess chiral centers and exhibit chirality. The article also expanded to cover the synthetic routes and metabolic routes for this versatile ring system and case studies for its utility to serve as bioisostere in drug discovery. Furthermore, this article also presents the receptor-ligand interactions of imidazole-based drugs with various target receptors. The present article is, therefore, put forth to assist medicinal chemists and chemists working in drug discovery of this versatile ring system.

Estimating Absolute Protein-Protein Binding Free Energies by a Super Learner Model

Protein-protein binding is central to most biochemical processes of all living beings. Its importance underlies mechanisms ranging from cell interactions to metabolic control, but also to ex vivo biotechnology, such as the development of therapeutic monoclonal antibodies, the engineering of enzymes for industrial biocatalysis, the development of biosensors for disease detection, and the assembly of artificial protein complexes for drug screening. Therefore, predicting the strength of their association allows for understanding the molecular mechanisms and ultimately controlling them. We devised a machine learning ensemble model that uses Rosetta-based quantities to predict binding free energies of protein-protein complexes with accuracy rivaling both computationally demanding methods and currently available ML/DL tools. The method was encoded into an application Python pipeline named PBEE, which stands for Protein Binding Energy Estimator, allowing a rapid calculation of the absolute binding free energies of protein complexes from their PDB coordinates.

An innovative approach to development of new pyrazolylquinolin-2-one hybrids as dual EGFR and BRAFV600E inhibitors

Novel quinoline-based derivatives 2a-e and 4a-j have been designed and synthesized as potential antiproliferative agents. The designed compounds were screened for their antiproliferative activity against sixty cell lines according to NCI protocol. The promising hybrids 4d-g are screened by MTT assays on three cancer cell lines: leukemia (MOLT-4), lung cancer (HOP-92), and breast cancer (T47D), with IC50 values ranging from 4.982 ± 0.2 to 36.52 ± 1.46 µM compared to Staurosporine, with compound 4e being the most effective. Derivatives 4d-g were evaluated for their inhibitory activity on EGFR and BRAFV600E. Compound 4e exhibited the highest inhibitory activities, with IC50 values of 0.055 ± 0.002 μM for EGFR and 0.068 ± 0.003 μM for BRAFV600E, compared to the reference drugs erlotinib (IC50 0.06 ± 0.002 μM) and vemurafenib (IC50 0.035 ± 0.001 μM), respectively. Cell cycle analysis of the HOP-92 manifested that pre-G1 apoptosis signaling took place after 4e treatment. Docking simulations were employed to analyze the modes and scores of compounds 4d-g with respect to EGFR and BRAFV600E. The results revealed that compound 4e exhibited strong affinity for both EGFR and BRAFV600E compared to the reference drugs with values of - 3.226 and - 3.474 kcal/mol, respectively.

Meta-, Regioselective Amination of Cyclic Diaryliodoniums through C-I and C-O Bond Cleavages: An Access to Functionalized Coumarins

Despite the widespread ortho-functionalization of cyclic diaryliodoniums in organic chemistry, the corresponding meta-functionalization is less explored. Herein, we report a practical meta-selective activation of cyclic hypervalent iodoniums for the synthesis of 4-amino coumarin derivatives in a broad functional group tolerance and environmentally friendly manner. The practicability of this protocol was further highlighted by the late-stage modification of some common pharmaceuticals and natural products.

A guide to selecting high-performing antibodies for Rab1A and Rab1B for use in Western Blot, immunoprecipitation and immunofluorescence

Rab1 is a highly conserved small GTPase that exists in humans as two isoforms: Rab1A and Rab1B, sharing 92% sequence identity. These proteins regulate vesicle trafficking between the endoplasmic reticulum (ER) and Golgi and within the Golgi stacks. Rab1A and Rab1B may be oncogenes, as they are frequently dysregulated in various human cancers. Moreover, they contribute to the progression of Parkinson's disease. The availability of high-quality antibodies specific for Rab1A or Rab1B is essential to understand the distinct functions of these Rab1 proteins in both health and diseaseand to enhance the reproducibility of research involving these proteins. In this study, we characterized seven antibodies targeting Rab1A and five antibodies targeting Rab1B for Western Blot, immunoprecipitation, and immunofluorescence using a standardized experimental protocol based on comparing read-outs in knockout cell lines and isogenic parental controls. These studies are part of a much larger, collaborative initiative seeking to address the antibody reproducibility issue by characterizing commercially available antibodies for human proteins and publishing the results openly as a valuable resource for the scientific community. While uses of antibodies and protocols vary between laboratories, we encourage readers to use this report as a guide to select the most appropriate antibodies for their specific needs.

Mitochondria-targeting nanostructures from enzymatically degradable fluorescent amphiphilic polyesters

Water-soluble π-conjugated luminescent bioprobes have been broadly used in biomedical research but are limited by the nonbiodegradability associated with their rigid C-C backbones. In the present work, we introduced three naphthalene monoimide (NMI)-functionalized amphiphilic fluorescent polyesters (P1, P2, and P3) prepared by transesterification of functional diols with an activated diester monomer of adipic acid. These polyesters featured a side-chain NMI fluorophore, imparting the required hydrophobicity for self-assembly in water and endowing the polymeric nanoassemblies with green fluorescence. Two polymers (P1 and P2) were intrinsically cationic at physiological pH (7.4), while neutral P3 exhibited pH-triggered (pH ∼6.2) cationic features due to the protonation of the tertiary amine groups present in its backbone. These biocompatible polymers revealed around 85% cellular uptake after 1 hour of incubation. However, the initial uptake for the cationic polymers (P1 and P2) within 15 minutes was significantly greater than that of the neutral P3 because of their stronger electrostatic interactions with the negatively charged cell membranes. Notably, cationic P1 and P2 could specifically target mitochondria in cancerous HeLa cells by escaping the initial endosome/lysosome trap. In contrast, neutral P3 exhibited cell-selective mitochondria targeting in cancerous (HeLa) cells over non-cancerous (NKE) cells. This is attributed to P3's protonation-induced positive charge accumulation in the acidic environment of cancer cells, unlike in the non-acidic environment of non-cancerous cells. This possibly causes P3 nanoassemblies to behave similarly to P1 and P2 in HeLa cells despite P3 being intrinsically neutral. The insights gained from this work may be relevant for future development of cell-specific, mitochondria-targeted drug delivery systems from enzymatically degradable polyester backbones.

Development of xanthone derivatives as effective broad-spectrum antimicrobials: Disrupting cell wall and inhibiting DNA synthesis

Discovering potent antibiotics is of critical importance due to the substantial increases of microbial resistance. Xanthones are intriguing sources of antimicrobials, despite a scarcity of extensive investigations into their mechanisms of action. Here, we reported the development of a series of xanthone derivatives, among which compound XT17 displayed strong broad-spectrum antibacterial activity, weak hemolytic activity, and low cytotoxicity against mammalian cell lines, low frequencies of drug resistance, and potent in vivo efficacy in Staphylococcu aureus- or Pseudomonas aeruginosa-induced murine corneal infection models. Compound XT17 presented a multifaceted mode of actions, involving the disruption of cell wall by interacting with lipoteichoic acid or lipopolysaccharides and the suppression of DNA synthesis. A further docking study confirmed the capability of compound XT17 to form a stable complex with the bacterial gyrase enzyme. This work could offer an innovative design strategy for developing broad-spectrum therapeutic agents against drug-resistant bacteria.

Silicon incorporated tacrine: design, synthesis, and evaluation of biological and pharmacokinetic parameters

Tacrine, an orally bioavailable cholinesterase inhibitor, was previously used to treat Alzheimer's disease but was withdrawn due to hepatotoxicity. The unique structural features of tacrine have once again captured the interest of medicinal chemists. However, the blood-brain barrier (BBB) permeability hampered the development of the majority of its new analogs. Herein, we employed a silicon switch approach for improving the BBB permeability of CNS drugs with tacrine as a tool compound. The replacement of C2 methylene of tacrine with dimethyl silicon yielded 'sila-tacrine' that inhibits acetylcholinesterase as well as butyrylcholinesterase with IC50 values of 3.18 and 6.09 μM, respectively. Sila-tacrine competitively inhibits acetylcholinesterase while it is a non-competitive inhibitor of butyrylcholinesterase. The molecular docking results corroborated with the in vitro cholinesterase inhibition activity of tacrine vs. sila-tacrine. Sila-tacrine demonstrated metabolic stability in HLM and MLM and exhibited superior plasma exposure in an oral pharmacokinetic study in Swiss albino mice. However, tissue distribution studies revealed lower-than-expected brain levels due to efflux pump-mediated transport. This study offers a proof-of-concept for the silicon switch approach in improving the BBB permeability of CNS-active compounds.

Pharmacophore screening, molecular docking, and MD simulations for identification of VEGFR-2 and c-Met potential dual inhibitors

Introduction

The vascular endothelial growth factor receptor 2 (VEGFR-2) and the mesenchymal-epithelial transition factor (c-Met) are critical in the pathogenesis and progression of various cancers by synergistically contributing to angiogenesis and tumor progression. The development of dual-target inhibitors for VEGFR-2 and c-Met holds promise for more effective cancer therapies that could overcome tumor cell resistance, a limitation often observed with inhibitors targeting a single receptor.

Methods

In this study, a computational virtual screening approach involving drug likeness evaluation, pharmacophore modeling and molecular docking was employed to identify VEGFR-2/c-Met dual-target inhibitors from ChemDiv database. Subsequent molecular dynamics (MD) simulations and MM/PBSA calculations were conducted to assess the stability of the protein-ligand interactions.

Results

From the virtual screening process, 18 hit compounds were identified to exhibit potential inhibitory activity against VEGFR-2 and c-Met. Among them, compound17924 and compound4312 possessed the best inhibitory potential according to our screening criteria.

Discussion

The analysis of the MD simulation results indicated that compound17924 and compound4312 showed superior binding free energies to both VEGFR-2 and c-Met when compared to the positive ligands. These findings suggested that both compounds were promising candidates for further drug development and could potentially serve as improved alternatives of cancer therapeutics.

Polycomb repressive complex 2 (PRC2) pathway's role in cancer cell plasticity and drug resistance

Polycomb Repressive Complex 2 (PRC2) is a central regulator of gene expression via the trimethylation of histone H3 on lysine 27. This epigenetic modification plays a crucial role in maintaining cell identity and controlling differentiation, while its dysregulation is closely linked to cancer progression. PRC2 silences tumor suppressor genes, promoting cell proliferation, metastasis, epithelial-mesenchymal transition, and cancer stem cell plasticity. Enhancement of zeste homolog 2 (EZH2) overexpression or gain-of-function mutations have been observed in several cancers, including lymphoma, breast, and prostate cancers, driving aggressive tumor behavior and drug resistance. In addition to EZH2, other PRC2 components, such as embryonic ectoderm development (EED) and suppressor of zeste 12, are essential for complex stability and function. EED, in particular, enhances EZH2 activity and has emerged as a therapeutic target. Inhibitors like MAK683 and EED226 disrupt EED's ability to maintain PRC2 activity, thereby reducing H3K27me3 levels and reactivating tumor suppressor genes. Valemetostat, a dual inhibitor of both EZH2 and EED, has shown promising results in aggressive cancers like diffuse large B-cell lymphoma and small-cell lung cancer, underlining the therapeutic potential of targeting multiple PRC2 components. PRC2's role extends beyond gene repression, as it contributes to metabolic reprogramming in tumors, regulating glycolysis and lipid synthesis to fuel cancer growth. Furthermore, PRC2 is implicated in chemoresistance, particularly by modulating DNA damage response and immune evasion. Tazemetostat, a selective EZH2 inhibitor, has demonstrated significant clinical efficacy in EZH2-mutant cancers, such as non-Hodgkin lymphomas and epithelioid sarcoma. However, the compensatory function of enhancer of zeste homolog 1 (EZH1) in some cancers requires dual inhibition strategies, as seen with agents like UNC1999 and Tulmimetostat, which target both EZH1 and EZH2. Given PRC2's multifaceted role in cancer biology, its inhibition represents a promising avenue for therapeutic intervention. The continued development of PRC2 inhibitors and exploration of their use in combination with standard chemotherapy or immunotherapy has great potential for improving patient outcomes in cancers driven by PRC2 dysregulation.

Reductive Zincke Reaction: Opening of Pyridinium Rings to δ-Amino Ketones via Transfer Hydrogenation

The Zincke reaction and Birch reduction have been one of the few reactions that allow for ring opening of pyridines ever since the discovery of pyridine more than a century ago. This paper presents a new addition to the list of pyridine ring-opening reactions, reductive Zincke reaction, which affords saturated δ-amino ketones. Under the catalysis of a simple rhodium complex, pyridinium salts with diverse substituents are reduced with formic acid, ring-opened with water, transaminated with a secondary amine and further reduced to afford a wide range of δ-amino ketones, including those in which the alkane chain of the ketones is selectively deuterated or fluorinated. The applicability of the reaction is exemplified by the synthesis of drug analogues and late-stage modification of drug molecules.

Fluorogenic Platform for Real-Time Imaging of Subcellular Payload Release in Antibody-Drug Conjugates

Antibody-drug conjugates (ADCs) represent promising therapeutic constructs to enhance the selective delivery of drugs to target cells; however, attaining precise control over the timing and location of payload release remains challenging due to the complex intracellular processes that define ADC internalization, trafficking, and linker cleavage. In this study, we present novel real-time fluorogenic probes to monitor both subcellular dynamics of ADC trafficking and payload release. We optimized a tandem molecular design of sequential pH- and enzyme-activatable naphthalimide fluorophores to (1) track their subcellular localization along the endolysosomal pathway and (2) monitor linker cleavage with OFF-to-ON fluorescence switches. Live-cell imaging microscopy revealed that fluorogenic ADCs can traffic to the lysosomes and yet require residence time in these subcellular compartments for efficient linker cleavage. Notably, the compact size of fluorogenic naphthalimides did not impair the recognition of target cell surface reporters or the kinetics of payload release. This modular platform is applicable to many ADCs and holds promise to inform their rational design for optimal release profiles and therapeutic efficacy.

Cefepime-taniborbactam and ceftibuten-ledaborbactam maintain activity against KPC variants that lead to ceftazidime-avibactam resistance

Klebsiella pneumoniae carbapenemases (KPCs) are widespread β-lactamases that are a major cause of clinical non-susceptibility of Gram-negative bacteria to carbapenems and other β-lactam antibiotics. Ceftazidime combined with the β-lactamase inhibitor avibactam (CAZ-AVI) has been effective in treating infections by KPC-producing bacteria, but emerging KPC variants confer resistance to the combination. Taniborbactam and ledaborbactam are bicyclic boronate β-lactamase inhibitors currently under development with cefepime and ceftibuten, respectively, to treat carbapenem-resistant bacterial infections. Here, we assessed the effects of clinically important KPC-2 and KPC-3 variants (V240G, D179Y, and D179Y/T243M) on the antibacterial activity of cefepime-taniborbactam (FEP-TAN) and ceftibuten-ledaborbactam (CTB-LED) and examined catalytic activity and inhibition of these variants. Unlike CAZ-AVI, FEP-TAN and CTB-LED were highly active against Escherichia coli strains expressing these KPC variants. Experiments with purified enzymes showed that FEP and CTB were poorly hydrolyzed by the KPC variants and had weak affinity for variants containing D179Y. In addition, the D179Y substitution in KPC-2 reduced inhibition by TAN and LED, but inactivation efficiencies (k2/K) for these inhibitors were significantly higher than those for AVI. K2/K was less affected for D179Y-containing KPC-3 variants, and robust inhibition was observed by TAN, LED, and AVI. Together, the findings illustrate a biochemical basis for FEP-TAN and CTB-LED efficacy in KPC variant-mediated CAZ-AVI resistance backgrounds, whereby the boronate inhibitors have sufficient inhibitory activity, while FEP and CTB are poor substrates and bind to the variant enzymes with reduced affinity.

Development of molecular Trojan horses targeting New Delhi metallo-β-lactamase-1 for the restoration of meropenem susceptibility in drug-resistant bacteria

The emergence of New Delhi metallo-β-lactamase-1 (NDM-1) poses a significant threat to the clinical application of antibiotics, as it possesses the ability to hydrolyze nearly all β-lactam antibiotics. Regrettably, there are currently no clinical drugs targeting NDM-1, making it imperative to develop highly potent and minimally toxic NDM-1 inhibitors. Herein, a series of molecular Trojan horses targeting NDM-1 were synthesized by introducing ebselen into 7-aminocephalosporanic acid derivatives via a C-Se bond. Representative compound 18b exhibited potent inhibitory activity against NDM-1, with an IC50 value of 7.03 μM, and combining with meropenem (Mem) decreased the minimum inhibitory concentration (MIC) of Mem by 4-32-fold in NDM-1 expressing bacteria. Mechanistically, 18b released the ebselen moiety at the active site of NDM-1, forming a Se-S bond with Cys208 to achieve targeted drug delivery of ebselen. Importantly, 18b demonstrated potent inhibition of resistant bacterial growth and replication in mice when administered in combination with Mem. These results suggest that 18b is a promising candidate for treating infections caused by resistant bacteria expressing NDM-1.

Functionalized regioisomers of the natural product phenazines myxin and iodinin as potent inhibitors of Mycobacterium tuberculosis and human acute myeloid leukemia cells

The natural bioactive products myxin and iodinin are phenazine 5,10-dioxides possessing potent anti-bacterial and anti-cancer activity in vitro. This work describes the synthesis and derivatization of new myxin and iodinin regioisomers, developed from 1,3-dihydroxyphenazine 5,10-dioxide. Compounds were evaluated for activity towards M. tuberculosis (Mtb) strains, a human AML cell line (MOLM-13), and two non-cancerous mammalian cell lines (NRK and H9c2). Highly potent analogs were developed having IC50 values against MTB down to 20 nM and 1.4 μM for human AML cells. 1-OH-3-O-alkyl substituted derivatives demonstrated high efficacy against Mtb and low toxicity in normal cells. 2,3-substituted regioisomers of myxin and iodinin were shown to be inactive, highlighting the importance of oxygen substituent in position 1 of the scaffold. A strong positive correlation between anti-MTB and anti-AML activity was revealed, suggesting a common mechanism of action in bacteria and cancer cells. These findings demonstrate the therapeutic potential of 1,3-O-functionalized phenazine 5,10-dioxides in chemotherapy for Mtb and AML and contribute to the structure-activity understanding of phenazine 5,10-dioxides with respect to their biological activity.

The polypharmacy combination of the BCL-2 inhibitor venetoclax (VEN) and the FLT3 inhibitor gilteritinib (GIL) is more active in acute myeloid leukemia cells than novel polypharmacologic BCL-2/FLT3 VEN-GIL hybrid single-molecule inhibitors

Current treatments for acute myeloid leukemias (AMLs) cure fewer than 30 % of patients. This low efficacy is due, in part, to the inter-patient and intra-patient heterogeneity of AMLs; accordingly, all current AML treatment regimens involve drug combinations (polypharmacy). A recently-completed clinical trial in relapsed/refractory AML using a combination of two newer targeted antileukemics, the BCL-2 inhibitor venetoclax (VEN) plus the FLT3 inhibitor gilteritinib (GIL), yielded highly promising results for this two-drug polypharmacy combination. Polypharmacology - wherein a single drug molecule that inhibits two or more biological targets is created - has been proposed to offer superior therapeutic results, as compared to the corresponding polypharmacy approach. Herein, we designed and synthesized several polypharmacologic dual BCL-2/FLT3 hybrid single-molecule inhibitors by tethering VEN to GIL, through their solvent-exposed domains. While the in vitro antileukemic activity of the two-drug VEN + GIL polypharmacy combination proved superior to our focused library of VEN-GIL hybrids, alternative grafting points on GIL may yield improved results for future hybrid compounds.

Efficacy of ginkgo biloba extract in the treatment of idiopathic pulmonary fibrosis: a systematic review and meta-analysis of randomized controlled trials

Objective

This systematic review and meta-analysis aims to assess the efficacy of GBE in the treatment of IPF by evaluating its impact on total effective rate, blood gas analysis, pulmonary function tests, and markers of inflammation and fibrosis.

Methods

We conducted a comprehensive search across seven databases, including PubMed, EMBASE, Web of Science, CNKI, Wanfang DATA, VIP, and CBM, without restrictions on publication date. Randomized controlled trials (RCTs) that investigated the effects of GBE on IPF patients were eligible for inclusion. Relevant literature was screened, and the data in the included studies were extracted for quality assessment according to the Risk of bias tool.

Results

A total of 14 RCTs involving 1043 patients were included in the analysis. GBE significantly improved the total effective rate, arterial oxygen partial pressure, arterial oxygen saturation, forced vital capacity, forced expiratory volume in one second, maximum voluntary ventilation, and 6-min walk test compared to the control group. Additionally, there was a significant reduction in arterial carbon dioxide partial pressure, interleukin-4, hyaluronan, and laminin levels.

Conclusion

GBE may offer therapeutic benefits in IPF by improving respiratory function, modulating inflammation, and affecting fibrosis markers. These findings support the potential use of GBE as an adjunct therapy in IPF and suggest that further large-scale, multicenter trials are warranted to confirm its efficacy and safety.

Structural insights, regulation, and recent advances of RAS inhibitors in the MAPK signaling cascade: a medicinal chemistry perspective

The MAPK pathway has four main components: RAS, RAF, MEK, and ERK. Among these, RAS is the most frequently mutated protein and the leading cause of cancer. The three isoforms of the RAS gene are HRAS, NRAS, and KRAS. The KRAS gene is characterized by two splice variants, K-Ras4A and K-Ras4B. The occurrence of cancer often involves a mutation in both KRAS4A and KRAS4B. In this study, we have elucidated the mechanism of the RAS protein complex and the movement of switches I and II. Only two RAS inhibitors, sotorasib and adagrasib, have been approved by the FDA, and several are in clinical trials. This review comprises recent developments in synthetic RAS inhibitors, their unique properties, their importance in inhibiting RAS mutations, and the current challenges in developing new RAS inhibitors. This review will undoubtedly help researchers design novel RAS inhibitors.

Toward Realization of Bioorthogonal Chemistry in the Clinic

In the last decade, the use of bioorthogonal chemistry toward medical applications has increased tremendously. Besides being useful for the production of pharmaceuticals, the efficient, nontoxic reactions open possibilities for the development of therapies that rely on in vivo chemistry between two bioorthogonal components. Here we discuss the latest developments in bioorthogonal chemistry, with a focus on their use in living organisms, the translation from model systems to humans, and the challenges encountered during preclinical development. We aim to provide the reader a broad presentation of the current state of the art and demonstrate the numerous possibilities that bioorthogonal reactions have for clinical use, now and in the near future.

Development of novel melatonin-isatin hybrids as multifunctional agents for Alzheimer's disease

The development of multifunctional agents has been a heated area of research for AD treatment in recent years. In this work, a series of melatonin-isatin hybrids were designed, synthesized, and evaluated as multifunctional agents for treating AD. In vitro studies indicated that most of the synthesized compounds displayed moderate to good MAO-B inhibition activities and good antioxidant activities. In particular, compounds IM-5 and IM-10 exhibited the best inhibitory activities with IC50 value of 12.4 μM and 15.6 μM against MAO-B, and potent antioxidant activities with their ORAC-FL values of 4.6 and 5.2 at 5 μM, respectively. ThT assay revealed compounds IM-5 and IM-10 exhibited the optimal Aβ1-42 self-induced aggregation inhibitory activities with the inhibition ratio of 72.8% and 69.7% at 20 μM. In addition, compounds IM-5 and IM-10 exhibited low cytotoxicities and significant neuroprotective effects on Aβ1-42-induced and H2O2-induced SH-SY5Y cell injury. More importantly, compounds IM-5 and IM-10 could significantly ameliorate the memory impairment and cognition injury in scopolamine-induced mice. The SwissADME program was used to predict drug-like properties of compounds IM-5 and IM-10 which exhibited they had good pharmacokinetics and drug-likeness properties. Molecular docking study further manifested that compounds IM-5 and IM-10 showed high hMAO-B inhibitory potency. In summary, all above results revealed compounds IM-5 and IM-10 might be promising multifunctional agents for AD treatment.

Synthesis of electrophile-tethered preQ1 analogs for covalent attachment to preQ1 RNA

The preQ1 cIass-I riboswitch aptamer can utilize 7-aminomethyl-7-deazaguanine (preQ1) ligands that are equipped with an electrophilic handle for the covalent attachment of the ligand to the RNA. The simplicity of the underlying design of irreversibly bound ligand-RNA complexes has provided a new impetus in the fields of covalent RNA labeling and RNA drugging. Here, we present short and robust synthetic routes for such reactive preQ1 and (2,6-diamino-7-aminomethyl-7-deazapurine) DPQ1 ligands. The readily accessible key intermediates of preQ0 and DPQ0 (both bearing a nitrile moiety instead of the aminomethyl group) were reduced to the corresponding 7-formyl-7-deazapurine counterparts. These readily undergo reductive amination to form the hydroxyalkyl handles, which were further converted to the haloalkyl or mesyloxyalkyl-modified target compounds. In addition, we report hydrogenation conditions for preQ0 and DPQ0 that allow for cleaner and faster access to preQ1 compared to existing routes and provide the novel compound DPQ1.

Conformationally Restricted Macrocycles as Improved FKBP51 Inhibitors Enabled by Systematic Linker Derivatization

Macrocycles are increasingly considered as promising modalities to target challenging intracellular proteins. However, strategies for transitioning from active linear starting points to improved macrocycles are still underdeveloped. Here we explored the derivatization of linkers as an approach for macrocycle optimization. Using the FK506-binding protein 51 (FKBP51) as a model system we prepared >140 macrocycles with systematically derivatized linkers. Two backbones were identified as promising frameworks for subsequent optimization. Surprisingly, co-crystal structure analyses revealed that these chemical templates represent an ensemble of three-dimensional (3D) conformations that can give rise to several distinct 3D-scaffolds. This resulted in a set of macrocycles with consistently improved affinity, plasma stability, and aqueous solubility compared to the linear precursors or the non-functionalized macrocycles. Our results highlight linkers as an opportunity for macrocyclic drug development, show how linker derivatization can improve the performance of macrocycles, and emphasizes the need to track macrocyclic scaffold evolution at a three-dimensional level.

Rhodium-mediated Assembly of New Heterocycles: From Borylenes to Oxaboroles

Base-stabilized rhodium borylene complex κ2-L(CO)Rh(BMes), 2; κ2-L=κ2-NN'-Rh,κ1-N-B-(2,5-[iPr2P=N(4-iPrC6H4)]2-N'(C4H2)-); Mes=mesityl, reacts with a series of alkynes (PhC≡C-R; R=Ph, Me, CO2Et, H) to yield unique structures whereby the alkyne has regioselectively added across boron and the carbon atom of a CO ligand. The resulting complexes, LRh[C(O)C(Ph)C(R)B(Mes)], 3R, react with additional CO to afford cycle-containing products, L(CO)Rh( P h C C R = B M e s O C ‾ ${(\overline{{\rm P}{\rm h}{\rm C}{\rm C}{\rm R}=B{\rm M}{\rm e}{\rm s}{\rm O}{\rm C}}}$ ), 5R, that ultimately release highly functionalized organic heterocycles of the formP h C = C R B M e s O C ‾ ${\overline{{\rm P}{\rm h}{\rm C}=C{\rm R}{\rm B}{\rm M}{\rm e}{\rm s}{\rm O}{\rm C}}}$ =NPipp (Pipp=4-iPrC6H4), 6. These oxaboroles, which were assembled from a primary hydroborane, CO, an alkyne, and an azide-generated NPipp, are structurally analogous to two of the five boron-containing therapeutics approved by the FDA.

Discovering Cell-Targeting Ligands and Cell-Surface Receptors by Selection of DNA-Encoded Chemical Libraries against Cancer Cells without Predefined Targets

Small molecules that can bind to specific cells have broad application in cancer diagnosis and treatment. Screening large chemical libraries against live cells is an effective strategy for discovering cell-targeting ligands. The DNA-encoded chemical library (DEL or DECL) technology has emerged as a robust tool in drug discovery and has been successfully utilized in identifying ligands for biological targets. However, nearly all DEL selections have predefined targets, while target-agnostic DEL selections interrogating the entire cell surface remain underexplored. Herein, we systematically optimized a cell-based DEL selection method against cancer cells without predefined targets. A 104.96-million-member DEL was selected against MDA-MB-231 and MCF-7 breast cancer cells, representing high and low metastatic properties, respectively, which led to the identification of cell-specific small molecules. We further demonstrated cell-targeting applications of these ligands in cancer photodynamic therapy and targeted drug delivery. Finally, leveraging the DNA tag of DEL compounds, we identified α-enolase (ENO1) as the cell surface receptor of one of the ligands targeting the more aggressive MDA-MB-231 cells. Overall, this work offers an efficient approach for discovering cell-targeting small molecule ligands by using DELs and demonstrates that DELs can be a useful tool to identify specific surface receptors on cancer cells.

Nickel-Catalyzed Reductive Hydrolysis of Nitriles to Alcohols

Nitriles are an abundant class of compounds that are widely used as versatile feedstocks to produce various chemicals including pharmaceuticals, and agrochemicals as well as materials. Here we report Ni-catalyzed reductive hydrolysis of nitriles to alcohols in the presence of molecular hydrogen. This conversion likely occurs in a domino reaction sequence that first involves the hydrogenation of nitrile to primary imine, then the hydrolysis of imine, and subsequent deamination to the aldehyde, which is finally hydrogenated to the desired alcohol. Crucial for this reductive hydrolysis process is the commercially available triphos-ligated Ni-complex that enables highly efficient and selective transformation of aromatic, heterocyclic, and aliphatic nitriles including fatty nitriles to prepare functionalized primary alcohols. Further, the synthetic applicability of this Ni-based protocol is presented for the selective conversion of nitrile to alcoholic group in structurally diverse and complex drug molecules as well as agrochemicals. The resulting products, alcohols are indispensable chemicals commonly used in organic synthesis and life sciences as well as material and energy technologies.