Synthesis, in vitro and in silico studies of a novel chrysin-ferrocene Schiff base with potent anticancer activity via G1 arrest, caspase-dependent apoptosis and inhibition of topoisomerase II

A novel chrysin-ferrocene Schiff base (CFSB) was synthesised as a potential anticancer agent. CFSB demonstrated high cytotoxicity against cancer cells with HepG2 (liver) being the most susceptible (IC50 = 3.11 µM). The compound was less toxic towards normal MRC5 cells and exhibited ∼5-fold selectivity towards most cancer cells. CFSB caused G1-phase arrest, induced caspase-dependent apoptosis by increasing Bax/Bcl2 ratio and reduced metastasis by decreasing MMP9 in HepG2. Furthermore, CFSB was inactive against CDK2, EGFR, TrkA and VEGFR, but it strongly inhibited topoisomerase II (IC50 = 20 µM) with potency comparable to etoposide (IC50 = 15 µM), while weak inhibition was observed against tubulin (IC50 = 76 µM). DFT calculations revealed that CFSB had desirable reactivity, while docking indicated high binding affinity with topoisomerase II. Molecular dynamics and MM-GBSA analyses showed that CFSB-topoisomerase II complex was stable with favourable binding energies, while in silico ADMET studies showed drug-like properties for CFSB.

Identification of host genetic factors modulating β-lactam resistance in Escherichia coli harbouring plasmid-borne β-lactamase through transposon-sequencing

Since β-lactam antibiotics are widely used, emergence of bacteria with resistance to them poses a significant threat to society. In particular, acquisition of genes encoding β-lactamase, an enzyme that degrades β-lactam antibiotics, has been a major contributing factor in the emergence of bacteria that are resistant to β-lactam antibiotics. However, relatively few genetic targets for killing these resistant bacteria have been identified to date. Here, we used a systematic approach called transposon-sequencing (Tn-Seq), to screen the Escherichia coli genome for host genetic factors that, when mutated, affect resistance to ampicillin, one of the β-lactam antibiotics, in a strain carrying a plasmid that encodes β-lactamase. This approach enabled not just the isolation of genes previously known to affect β-lactam resistance, but the additional loci skp, gshA, phoPQ and ypfN. Individual mutations in these genes modestly but consistently affected antibiotic resistance. We have identified that these genes are not only implicated in β-lactam resistance by itself but also play a crucial role in conditions associated with the expression of β-lactamase. GshA and phoPQ appear to contribute to β-lactam resistance by regulating membrane integrity. Notably, the overexpression of the uncharacterized membrane-associated protein, ypfN, has been shown to significantly enhance β-lactam resistance. We applied the genes identified from the screening into Salmonella Typhimurium and Pseudomonas aeruginosa strains, both critical human pathogens with antibiotic resistance, and observed their significant impact on β-lactam resistance. Therefore, these genes can potentially be utilized as therapeutic targets to control the survival of β-lactamase-producing bacteria.

Structural comparison of substrate-binding pockets of serine β-lactamases in classes A, C, and D

β-lactams have been the most successful antibiotics, but the rise of multi-drug resistant (MDR) bacteria threatens their effectiveness. Serine β-lactamases (SBLs), among the most common causes of resistance, are classified as A, C, and D, with numerous variants complicating structural and substrate spectrum comparisons. This study compares representative SBLs of these classes, focusing on the substrate-binding pocket (SBP). SBP is kidney bean-shaped on the indented surface, formed mainly by loops L1, L2, and L3, and an additional loop Lc in class C. β-lactams bind in a conserved orientation, with the β-lactam ring towards L2 and additional rings towards the space between L1 and L3. Structural comparison shows each class has distinct SBP structures, but subclasses share a conserved scaffold. The SBP structure, accommodating complimentary β-lactams, determines the substrate spectrum of SBLs. The systematic comparison of SBLs, including structural compatibility between β-lactams and SBPs, will help understand their substrate spectrum.

Discovery of novel biphenyl compounds bearing hydroxamic acid moiety as the first PD-L1/class I HDACs dual inhibitors

Herein, we firstly reported a series of biphenyl compounds bearing hydroxamic acid moiety as PD-L1/class I HDACs dual inhibitors. Among them, compound 14 displayed the strongest inhibitory activity in vitro against HDAC2 and HDAC3 with IC50 values of 27.98 nM and 14.47 nM, and had an IC50 value of 88.10 nM for PD-1/PD-L1 interaction. Importantly, 14 could upregulate the expression of PD-L1 and CXCL10 in a PD-L1 low-expression cancer cell line (MCF-7), highlighting the potential to enhance efficacy by recruiting T-cell infiltration into TME and improving the response of PD-1/PD-L1 inhibitor associated with PD-L1 low-expression. Besides, we identified another compound, 22, which possessed the strongest inhibitory activity against PD-1/PD-L1 interaction with an IC50 value of 12.47 nM, and effectively inhibited the proliferation of three cancer cell lines. Our results suggest that compounds 14 and 22 can be served as lead compounds of PD-L1/class I HDACs dual inhibitors for further optimisation.

Exploring covalent inhibitors of SARS-CoV-2 main protease: from peptidomimetics to novel scaffolds

Peptidomimetic inhibitors mimic natural peptide substrates, employing electrophilic warheads to covalently interact with the catalytic Cys145 of Mpro. Examples include aldehydes, α-ketoamides, and aza-peptides, with discussions on their mechanisms of action, potency, and structural insights. Non-peptidomimetic inhibitors utilise diverse scaffolds and mechanisms, achieving covalent modification of Mpro.

Bioactivity profiling of Sanghuangporus lonicerinus: antioxidant, hypoglycaemic, and anticancer potential via in-vitro and in-silico approaches

This study investigates the mycochemical profile and biological activities of hydroethanolic (EtOH), chloroform (CHCl3), and hot water (H2O) extracts of Sanghuangporus lonicerinus from Uzbekistan. Antioxidant capacity was assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), NO, and FRAP assays, and in vitro hypoglycaemic effects were evaluated through α-amylase and α-glucosidase inhibition. Antiproliferative potential was explored by analysing the binding affinities of EtOH and H2O extracts to estrogen receptor α (ERα), ERβ, androgen receptor (AR), and glucocorticoid receptor (GR), with molecular docking providing structural insights. LC-MS/MS analysis revealed solvent-dependent phenolic profiles, with the EtOH extract containing the highest total phenolic content (143.15 ± 6.70 mg GAE/g d.w.) and the best antioxidant capacity. The EtOH extract showed significant hypoglycaemic effects, with 85.29 ± 5.58% inhibition of α-glucosidase and 41.21 ± 0.79% inhibition of α-amylase. Moderate ERβ binding suggests potential for estrogen-mediated cancer therapy, while strong AKR1C3 inhibition by the EtOH extract supports its therapeutic potential.

Tetra-anionic porphyrin mimics protein-protein interactions between regulatory particles and the catalytic core, allosterically activating human 20S proteasome

Decreased proteasome activity is a hallmark of brain and retinal neurodegenerative diseases (Alzheimer's, Parkinson's diseases, glaucoma) boosting the search for molecules acting as proteasome activators. Based on the hypothesis of an electrostatic key code driving catalytic core particle (20S) activation by regulatory particles (RPs), we identified the tetra-anionic meso-Tetrakis(4-sulphonatophenyl)-porphyrin (H2TPPS) as a new activator of human proteasome. By means of an integrated approach, including bioinformatics, enzymatic kinetic analysis, atomic force microscopy, and dynamic docking simulations, we show how binding of H2TPPS affects the closed/open conformational equilibrium of human 20S to ultimately promote substrate gate opening and proteolytic activity. These outcomes support our hypothesis and pave the way to the rational discovery of new proteasome allosteric modulators able to reproduce the key structural elements of regulatory particles responsible for catalytic activation.

Discussion on the mechanism of HER2 resistance in esophagogastric junction and gastric cancer in the era of immunotherapy

Human epidermal growth factor receptor 2 (HER2) is a critical biomarker and therapeutic target in gastric/gastroesophageal junction (G/GEJ) cancers, despite the initial success of HER2-targeted therapies, such as trastuzumab, resistance to these drugs has emerged as a major impediment to effective long-term treatment. This review examines the mechanisms of drug resistance in HER2-positive G/GEJ cancer, the primary mechanisms of resistance explored include alterations in the HER2 receptor itself, such as mutations and changes in expression levels, as well as downstream signaling pathways, and interactions with the tumor microenvironment (TME). Furthermore, the review discusses the Novel therapeutic approaches, including the use of antibody-drug conjugates (ADCs) and combination therapies are assessed for their potential to enhance outcomes. By integrating recent research findings and clinical trials, this review aims to provide oncologists and researchers with insights into developing more effective treatments for patients with drug-resistant HER2-positive G/GEJ cancer.

Rational design, synthesis, and molecular modelling insights of dual DNA binders/DHFR inhibitors bearing arylidene-hydrazinyl-1,3-thiazole scaffold with apoptotic and anti-migratory potential in breast MCF-7 cancer cells

In light of searching for new breast cancer therapies, DNA-targeted small molecules were rationally designed to simultaneously bind DNA and inhibit human dihydrofolate reductase (hDHFR). Fourteen new arylidene-hydrazinyl-1,3-thiazoles (5-18) were synthesised and their dual DNA groove binding potential and in vitro hDHFR inhibition were performed. Two compounds, 5 and 11, proved their dual efficacy. Molecular docking and molecular dynamics simulations were performed for those active derivatives to explore their mode of binding and stability of interactions inside DHFR active site. Anti-breast cancer activity was assessed for 5 and 11 on MCF-7 cells using MTX as reference. IC50 measurements revealed that both compounds were more potent and selective than MTX. Cytotoxicity was examined against normal skin fibroblasts to examine safety and selectivity Moreover, mechanistic studies including apoptosis induction and wound healing were performed. Further in silico ADMET assessment was conducted to determine their eligibility as drug leads suitable for future optimisation and development.

Synthesis and characterization of a solvatochromic urea-schiff base derivative: Investigating optical properties, hydrogen bonding effect, copper ion sensing, computational analysis, DNA and β-cyclodextrin interactions

This study investigates the fluorescence behavior of the synthesized compound (E)-1-(4-chloro-2-(((2-hydroxynaphthalen-1-yl) methylene) amino) phenyl)-3-(naphthalen-1-yl) urea (3DB) in various solvents. A significant increase in fluorescence intensity was observed when transitioning from ethanol to less polar solvents like CH2Cl2, CHCl3, and CCl4, indicating enhanced fluorescence due to reduced non-radiative processes. Emission wavelengths remained stable with minor shifts (5-6 nm), while significant blue shifts in absorption occurred in water due to strong hydrogen bonding. Fluorescence spectra showed red shifts (519 nm in water, 508 nm in glycerol, and 486 nm in ethylene glycol), highlighting the impact of hydrogen bonding on electronic transitions. Emission intensity in water was six times higher than in ethylene glycol, suggesting that strong hydrogen bonds stabilize the excited state. The study also revealed that 3DB exhibits a large Stokes shift, avoiding reabsorption of emitted light (inner filter effect). Fluorescence was completely quenched by low concentrations of copper ions, demonstrating 3DB's potential as a copper sensor. Density functional theory (DFT) and time-dependent DFT (TDDFT) calculations indicated that luminescence quenching in the Cu(II) complex is due to intramolecular charge transfer (ICT). Additionally, 3DB formed stable complexes with DNA and β-cyclodextrin (β-CD), with binding constants (Kb) of 1.30 × 103 M-1 and 1.89 × 103 M-1, respectively, and negative Gibbs free energy values, indicating spontaneous interactions. Fluorescence spectroscopy confirmed DNA binding, showing a 49.62 % increase in intensity and a 4 nm blue shift, consistent with groove-binding. Docking studies further supported favorable interactions with DNA. These results underscore 3DB's potential in sensing, imaging, environmental monitoring, and biological applications.

Dimer peptidomimetics-based non-toxic immunoassay for bongkrekic acid in food and biosamples compatible with smartphone demonstration

Non-toxic immunoassays are effective analytic methods that offer enhanced safety and cost efficiency by substituting toxins with peptidomimetics. Bongkrekic acid (BA), a highly lethal bacterial toxin, has recently garnered significant attention due to its toxicity. This work isolated a phage-borne peptide (CFSFQVGDC) with a strong binding affinity to an anti-BA monoclonal antibody (mAb) from a peptide phage library. Monomer and dimer peptidomimetics were synthesized to achieve a phage-free peptide. ELISA revealed a detection sensitivity of 0.63 ng/mL for the dimer, which is 120-fold higher than that of the monomer. Meanwhile, computer-aided simulations revealed that the enhancement of the hydrogen bonding network of the dimer was the key factor driving its stronger binding affinity. Then, a sensitive immunochromatographic assay (ICA) based on the dimer peptidomimetic was developed to detect BA, compatible with smartphone demonstration. The visible limit of detection (vLOD) was 2.50 μg/kg, while the quantitative limit of detection (qLOD) was 0.12 μg/kg. The recovery rates for real samples, including blood and urine, ranged from 85.00 % to 115.20 %, consistent with standard LC-MS/MS. Importantly, the dimer restored binding capacity to levels comparable to the native toxin, laying a robust foundation for further optimization of toxin-free peptide designs via directed evolution. The developed ICA platform also provided an alternative method for the non-toxic, sensitive, and on-site detection of BA.

Characterization of a dual degrader of MDM2 and GSPT1

Murine double minute 2 (MDM2) has long been a therapeutic target to stabilize and upregulate wild-type tumor protein 53 (p53) in cancer. We initially reported WB156 as a degrader of MDM2 that can upregulate p53 levels in acute leukemia. To further evaluate the therapeutic potential of WB156, we tested it in a variety of cancers alongside another reported MDM2 degrader. We found that WB156 is active in wild-type and mutant p53-bearing leukemias due to its ability to degrade both MDM2 and G1 To S Phase Transition 1 (GSPT1) protein. In cancers that are non-responsive to MDM2 degradation alone, WB156 acts as a GSPT1 degrader to induce anti-proliferative effects. Here, we report the first MDM2/GSPT1 dual degrader that also upregulates p53 levels.

Nicotinamide N-methyltransferase in cardiovascular Diseases: Mechanistic insights and therapeutic potential

Cardiovascular diseases (CVDs), including conditions like ischemic heart disease, heart failure (HF), and atherosclerosis (AS), have complex pathogenesis that involves both behavioral and metabolic factors. Nicotinamide N-methyltransferase (NNMT) is an enzyme involved in the methylation of nicotinamide (NAM), and its increased activity is associated with disruptions in the NAD+ and methionine cycles. These disruptions are considered significant risk factors for cardiovascular diseases, though the specific mechanisms of NNMT remain unclear. This review discusses the role of NNMT in cardiovascular diseases by modulating NAD+ and methionine metabolism, including mechanisms such as NAD+ depletion, mitochondrial energy crisis, SIRTs deactivation, PARP hyperactivation, as well as hyperhomocysteinemia and epigenetic dysregulation. NNMT is linked to diseases such as atherosclerosis, pulmonary arterial hypertension, heart failure, and coronary heart disease, playing a critical role in their progression. Moreover, the potential of NNMT as a therapeutic target for cardiovascular diseases is explored. RNAi therapies, NNMT small-molecule inhibitors, and exercise therapies are promising treatment approaches, but there are limitations in current research, including discrepancies between animal models and human tissue expression, the dual role of NNMT, and the dose-dependent effects of NNMT inhibitors. Future studies should further clarify NNMT's mechanisms and assess its feasibility as a therapeutic target, aiming to develop more effective treatments and enhance prevention and treatment strategies for cardiovascular diseases.

A novel colorimetric assay for early differentiation of mucocutaneous and cutaneous leishmaniasis via species-specific identification

Mucocutaneous leishmaniasis (MCL) is a severe and debilitating progression of cutaneous leishmaniasis (CL) that occurs when the disease spreads to involve mucosal tissues. Contrasting CL, which can often be treated with local therapies, MCL requires aggressive systemic treatment, strict adherence to a 30-day regimen and regular monitoring to prevent recurrence. These requirements highlight the critical need for accurate and rapid early diagnosis to guide effective treatment strategies. However, differentiating between the Leishmania species responsible for MCL and CL remains a significant challenge, particularly in resource-limited settings. To address this gap, this study introduces a novel colorimetric assay that integrates the Spin-Tube platform with Dynamic Chemical Labeling (DCL) technology for species-specific identification of Leishmania parasites. This approach targets single nucleotide fingerprints (SNFs) within the conserved hsp70 gene, allowing precise differentiation between species associated with MCL and CL. The assay employs single-plex PCR followed by DCL-based detection of SNFs, providing rapid and visually interpretable results to facilitate species differentiation. The assay demonstrated remarkable sensitivity, with a detection limit of 1 copy of parasite DNA per μL and performed effectively even under resource-limited conditions. It was used to identify ten MCL patients, with the results confirmed through DNA sequencing. Its simplicity and rapid turnaround could make it an ideal diagnostic solution for endemic regions. By providing accurate early differentiation between CL and MCL, this assay enables the implementation of personalised treatment plans, minimising unnecessary exposure to toxic therapies and reducing the risk of irreversible mucosal damage for affected patients.

Discovery of indole derivatives as STING degraders

Aberrant activation of the stimulator of interferon genes (STING) pathway is associated with the development of various inflammatory and autoimmune diseases. Targeting STING for degradation represents a novel strategy for the treatment of these diseases. In this study, we designed and synthesized a series of STING-PROTACs based on a nitro-free covalent warhead and different E3 ligase binders. The representative compound 2h specifically degraded STING protein through the proteasome pathway with a DC50 value of 3.23 μM and exhibited sustained degradation activity over 72 h. Further biological studies demonstrated that compound 2h inhibited STING signaling and effectively suppressed immune-inflammatory cytokines both in vitro and in vivo. Moreover, compound 2h offered better safety compared to its warhead molecule and SP23. Collectively, compound 2h is a potent nitro-free covalent STING degrader and warrants further investigation.

Therapeutic potential of dual HDAC6/SIRT2 inhibition in Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by hallmark pathological changes such as amyloid β (Aβ) plaques, neurofibrillary tangles (NFTs) due to tau hyperphosphorylation, and neuroinflammation. Current therapeutic approaches focusing on single-target strategies exhibit limited efficacy, necessitating the exploration of novel multi-target approaches. Histone deacetylase 6 (HDAC6) and SIRT2, as two types of cytosolic histone deacetylases, have emerged as promising targets for AD treatment. HDAC6 plays a role in tau protein phosphorylation, while SIRT2 is involved in Aβ production. Both enzymes regulate microtubule proteins, impacting the formation of NFTs and Aβ plaques. Inhibition of HDAC6 reduces tau hyperphosphorylation, improves microtubule stability, and mitigates neuroinflammation, whereas SIRT2 inhibition attenuates Aβ accumulation and neuroinflammation. Recent studies indicate that dual-targeted inhibition of HDAC6 and SIRT2 may exhibit synergistic effects, suggesting it as a promising strategy for AD treatment. This review summarizes the biological roles of HDAC6 and SIRT2 in AD pathology and examines the development of dual-target inhibitors. It also discusses the challenges, including selectivity and toxicity, emphasizing that the development of combined HDAC6 and SIRT2 inhibitors represents a new direction for future AD treatment.

Design and development of chromene-3-carboxylate derivatives as antidiabetic agents: Exploring the antidiabetic potential via dual inhibition of angiotensin II type 1 receptor and neprilysin enzyme

Diabetes mellitus, particularly type II diabetes mellitus, is a metabolic condition that has a substantial impact on the health of individuals. The implication of diabetes with increased risk of cardiovascular diseases (CVD) and, consequently, myocardial infarction is well established. However, developing new antidiabetic drugs with an established efficacy on cardiovascular health is an underdeveloped area of research. To address this, in the present study, a new series of chromene-3-carboxylate derivatives (1B1-1B22) as dual inhibitors of Angiotensin II Type 1 Receptor (AT1R) and Neprilysin (NEP), which are recognized targets in diabetes with CVD, is reported. The compounds were rationally designed and synthesized, considering the pharmacophoric features of these two targets. The evaluation was performed via glucose uptake, α-amylase, AT1R, and NEP inhibition assay. The derivatives were found to increase glucose uptake and inhibit all three targets, of which compound 1B15 was the most active. The most active compound, 1B15, reduced the oxidative stress and restored the mitochondrial membrane potential. The biological findings were further corroborated by in silico studies, which included molecular modelling and dynamics. It was deduced that 1B15 remains unionized in acidic to weak basic pH and may be passively absorbed. Further, the molecule was found to undergo hydroxylation as a means of Phase I metabolism and glucuronic conjugation in Phase II. The wet lab experiments on 1B15 further validated the in-silico absorption and metabolism prediction. The compounds, particularly 1B15, could be explored further as a lead for its utility as an antidiabetic with profound implications on cardiovascular health.

Design and synthetic approaches to thalidomide based small molecule degraders

Thalidomide has been used as a repurposed drug for treating multiple myeloma since 1997. Several novel anticancer drugs containing thalidomide active moiety has been discovered since then. Many thalidomide drug candidates with tuned linker size have been instrumental in inhibiting histone deacetylase, kinase, transcription factors etc. and facilitate selective degradation of E3 ligase and other enzymes. Here we are focused on small molecule degraders that are being tailored with tweaking synthetic architectures around thalidomide chemical motif towards the development of promising drug candidates. Interesting biomedical applications of thalidomide-based degraders with recent developments including pharmacokinetic profiles, protein stability, activity studies, degradation assays, and antitumor response are elucidated.

Exploring indole-dihydropyrimidinone derivatives: Design, synthesis, biological assessment, SAR analysis, and evaluation of mode of action in experimental visceral leishmaniasis

The emergence of drug resistance and the non-availability of vaccines encouraged us to identify novel chemical scaffolds as new anti-leishmanial agents. In doing so, a series of thirty-four indole-dihydropyrimidinone hybrid compounds were synthesized using the Biginelli multicomponent reaction. These synthesized compounds were tested against L. donovani in vitro and in vivo in experimental golden hamster model of visceral leishmaniasis. Compounds 4f and 4m were found to have promising anti-leishmanial properties against intracellular amastigotes (IC504.54 & 5.05 μM, respectively) with minimal cytotoxicity against J774.1 macrophage. 4f and 4m were tested in vivo, and only 4f effectively cleared the parasite burden (>65 %) in infected golden hamsters. Mode of action studies discloses that 4f induces oxidative stress-mediated mitochondrial dysfunction and impairment of ATP production and triggers apoptosis. SAR and PK studies revealed that compound 4f (indole-dihydropyrimidinone hybrid) may be used as a lead for developing future chemotherapeutic options for VL.

D-(+)-Biotinylated squaraine dyes: A journey from synthetic conception, photophysical and -chemical characterization, to the exploration of their photoantitumoral action mechanisms

Biotin is primarily taken up by cells through sodium-dependent multivitamin transporter, which is highly expressed in aggressive cancer cell lines, often at levels surpassing those of the folate receptor. This makes biotin an attractive ligand for tumor-targeted drug delivery. Building on this rationale, this study presents a series of six D-(+)-biotin-conjugated squaraine dyes derived from benzothiazole, indolenine, and benz[e]indole, with N-ethyl and N-hexyl chains. These compounds were thoroughly characterized in terms of their photophysical and photochemical properties, revealing strong absorption in the so-called "phototherapeutic window", notable fluorescence, especially the benzothiazole derivatives, aqueous stability, particularly the indolenine-based dyes, and moderate to high photostability. Computational studies further indicated a strong binding affinity to human serum albumin and avidin proteins. All dyes exhibited photodynamic activity, with indolenine derivatives showing remarkable tumor selectivity and benz[e]indole analogs evidencing superior photocytotoxicity. The most promising compounds preferentially accumulated in mitochondria, and both singlet oxygen and other reactive oxygen species were found to play a role in their photobiological effects. Additionally, they were non-genotoxic in the absence of irradiation, and apoptosis was the primary mechanism of cell death upon light activation. This was evidenced by preserved cytoplasmic membrane integrity, nuclear fragmentation, and caspase-3/7 activation, reinforcing the safety and potential of these compounds as phototherapeutic agents. Although cellular uptake via the sodium-dependent multivitamin transporter was not established, and diffusion is expected to be the predominant mechanism, the high predicted avidin-binding affinity of these dyes opens exciting new avenues for photodynamic therapy-combined strategies.

Development of Carprofen analogues with activity against Mycobacterium tuberculosis

Carprofen, a veterinary non-steroidal anti-inflammatory drug, has demonstrated bactericidal activity against Mycobacterium tuberculosis and the closely related model organism M. bovis BCG. Herein, we present the SAR-driven optimisation of three series of carbazole-based carprofen analogues for increased antimycobacterial potency and selectivity over the human monocyte-derived THP-1 cell line. An efficient synthetic route was employed to assemble a range of carprofen analogues which were then evaluated in whole-cell phenotypic assays to establish their activity against well-studied model organisms for M. tuberculosis. The most promising compound was further profiled against M. tuberculosis H37Rv, confirming the identification of a potent antitubercular carbazole with significantly enhanced therapeutic potential.

Synthesis and in vivo biological characterization of six carbon-11 sigma-1 receptor radiotracers in rodent and nonhuman primate

Six enantiomers of three racemic sigma-1 receptor (σ1R) ligands were resolved, and absolute configuration was determined. Their high σ1R potency and selectivity were determined through in vitro binding assays, further validated by molecular docking analysis. Central Nervous System Multiparameter Optimization algorithm (CNS MPO) predicts efficient brain penetration for these enantiomers. Six C-11 radiotracers were radiosynthesized successfully, ex vivo biodistribution in rats showed that (-)-[11C]7 had high brain uptake of ∼4.8-fold for 5 min versus 60 min. Mouse brain PET imaging studies showed (-)-[11C]7 and (-)-[11C]16 have in vivo binding specificity for σ1R. Macaque PET scans showed high brain uptake for all six radiotracers, with (-)-[11C]7 peaked at ∼45 min (SUV 2.5), possessing the best washout kinetics and highest cerebellum-to-white matter ratio (∼3.1), in agreement with in vitro or ex vivo measures of σ1R expression. Radiometabolite analysis showed that no newly formed radiometabolite was observed post-injection of (-)-[11C]7. Our data suggest that further evaluation is warranted to determine that (-)-[11C]7 is a suitable PET radiotracer for imaging σ1R in the brain of animal and human.

Screening and evaluation of hydrophobic cell-penetrating peptides for antisense oligonucleotide delivery

Antisense oligonucleotides (ASOs) are promising therapeutic agents targeting intracellular RNA, yet their clinical application is limited by poor membrane permeability. To overcome this challenge, we investigated hydrophobic cell-penetrating peptides (CPPs) as alternative delivery vectors. Ten hydrophobic CPPs were synthesized and screened for cellular uptake using live-cell fluorescence imaging. Selected CPPs were conjugated to a chemically modified ASO via click chemistry, and their intracellular delivery and antisense efficacy were evaluated using a splicing reporter assay in HeLa 705 cells. While certain CPPs, such as MPG, showed high membrane permeability, conjugation with ASOs did not always translate to enhanced antisense activity. Notably, among the evaluated CPP-ASO conjugates, SP-ASO exhibited the most potent functional activity despite moderate uptake. This finding suggests that factors beyond membrane permeability, such as endosomal escape, intracellular trafficking, or nuclear delivery efficiency, may critically influence the overall efficacy. Fluorescence microscopy confirmed lysosomal entrapment of both naked and CPP-conjugated ASOs. These findings emphasize the importance of rational design strategies that address endosomal release to maximize the therapeutic potential of CPP-ASO conjugates.

Structure based design, synthesis and identification of novel covalent reversible dual TLR2/TLR9 small molecule antagonists

Inflammation is a key driver of the onset and progression of neurodegenerative diseases and cancer and can be caused by aggregated proteins, injured neurons or synapses, dysregulation of inflammatory control mechanisms, and other factors. Tolllike receptors (TLRs) are important mediators of inflammatory pathways, and their activation leads to pro-inflammatory cytokine release by immune cells in the periphery or in the central nervous system (CNS). TLR2 and TLR9 are implicated in the inflammatory pathogenesis of CNS degenerative diseases such as Parkinson's Disease (PD) and amyotrophic lateral sclerosis (ALS). They are also held to be important in the etiology of certain malignancies like inflammatory pancreatic ductal adenocarcinoma and glioblastoma. Inactivation of TLR2/9 in animal models of neurodegeneration has reduced pathological markers and diminished neuronal loss, while in animal models of cancer it has suppressed tumors. Therefore, TLR2 and TLR9 may be potential targets for the treatment of neurodegenerative disorders and cancers. We identified for the first time a key binding locus in TLR2/9 TIR domain which guided reversible covalent drug (RCD) design of a novel, first-in class series of dual TLR2/9 antagonists. Sub-micromolar antagonist concentrations potently inhibited TLR2 and TLR9 signaling induced by TLR2/9 specific agonists. Importantly, this series of antagonists did not discernably activate other TLRs and exhibited favorable in-vitro ADME and safety. The analogs described here may help realize effective TLR2/9 antagonism as a viable therapeutic strategy for inflammation driven CNS diseases and various malignancies with an inflammatory etiology.

Virtual screening and fragment growth strategy for developing near-infrared fluorescent probes to detect Aβ in Alzheimer's disease model

Amyloid fibrils are well-established biomarkers of Alzheimer's disease (AD), and the development of novel near-infrared fluorescent (NIRF) probes for early detection of β-amyloid can help differentiate AD from other neurodegenerative conditions. In this study, we report the discovery of an effective NIRF probe, probe 6-4, through a combined approach of virtual screening and fragment growth. Probe 6-4 binds strongly to Aβ oligomers and aggregates, showing robust fluorescent properties with an emission maximum near 650 nm when bound to Aβ aggregates and oligomers. It exhibits high sensitivity, with a nearly 100-fold increase in fluorescence intensity, and strong affinity (Kd = 9.4 nM for oligomers and 12.5 nM for aggregates). In vivo and ex-vivo NIRF imaging studies further demonstrated that probe 6-4 can distinguish AD transgenic model mice from wild-type controls. Overall, probe 6-4 proves to be a potent and efficient tool for detecting Aβ aggregates and oligomers in the brain, validating the effectiveness of combining virtual screening and fragment growth in developing NIRF probes for AD research.

Annual review of EGFR inhibitors in 2024

Epidermal growth factor receptor (EGFR) inhibitors play a crucial role in the treatment of EGFR mutation-driven cancers, such as non-small cell lung cancer (NSCLC). In 2024, significant breakthroughs were made in new drug development, resistance mechanisms, and combination therapy strategies. This review summarizes the key studies published in 2024, with a focus on the design strategies, structure-activity relationships (SAR), mechanisms of action, and both in vitro and in vivo activities of EGFR inhibitors. The aim is to provide new research perspectives and theoretical foundations for developing highly effective and selective inhibitors targeting diverse EGFR mutations.

Effects of mono-substituents on the polarity-sensitive fluorescent probe properties of pyrene

This study investigates the effects of mono-substituents (i.e., hydroxyl, methyl, amino and nitro groups) on the polarity-sensitive fluorescent probe properties of pyrene (Pyr) using fluorescence, UV-vis, and circular dichroism absorption spectroscopy. The results indicate that the four mono-substituents altered the fluorescence spectral characteristics of Pyr to varying degrees, with the most to least influential order being: nitro, amino, hydroxyl, and methyl. 1-Aminopyrene (1-APyr) and 1-nitropyrene (1-NPyr) are deemed unsuitable for use as polarity-sensitive fluorescent probes due to their limited or absent spectral characteristics. The I386/I406 and I376/I396 ratios of 1-HPyr and 1-MPyr decrease as solvents polarity increases, contrasting with the I372/I384 ratio of Pyr. Thus, 1-hydroxypyrene (1-HPyr) and 1-methylpyrene (1-MPyr) also exhibit polarity-sensitive characteristics similar to Pyr, and their solubility in PBS buffer surpasses that of Pyr at 298 K. Moreover, 1-HPyr and 1-MPyr are practicable for detecting the polarity of human serum albumin (HSA) under simulated physiological conditions. The results underscore the potential of the polarity-sensitive mono-substituents of Pyr in biological applications, particularly in probing protein polarity and conformational changes, and further providing a potential tool for the related research in biochemistry and pathology.

19F NMR in RNA structural biology: exploring structures, dynamics, and small molecule interactions

RNA molecules play essential roles in numerous biological pathways, making them attractive targets for drug discovery. Despite the challenges in developing small molecules targeting RNA, the success in developing compounds that modulate RNA function underscores its therapeutic potential. 19F NMR spectroscopy has emerged as a powerful tool in structural biology and drug discovery, particularly for studying macromolecular structures and ligand interactions. As RNA continues to gain prominence as a drug target, 19F NMR is expected to play a pivotal role in advancing RNA-focused drug discovery. This review describes the diverse applications of 19F NMR in RNA biology, including its use in characterizing RNA structures, probing molecular dynamics, identifying small-molecule binders, and investigating interaction mechanisms of small-molecule ligands. By providing detailed structural and ligand binding insights, 19F NMR will facilitate the discovery of RNA-targeting therapeutics and deepen our understanding of RNA modulatory mechanisms.

Molecular mechanisms of antibiotic inhibition on microbial dissimilatory iron reduction

Microbe-mediated iron cycling plays a pivotal role in biogeochemical processes. However, the impact of trace-level antibiotics on microbially mediated dissimilatory iron reduction (DIR) remains unexplored. In this study, we investigated the effects of four typical antibiotics on DIR mediated by Shewanella oneidensis MR-1, with a focus on their inhibitory effects on three extracellular electron transfer (EET) pathways: 1) direct EET, 2) soluble redox mediator-dependent EET, and 3) nanowire-mediated EET. Our findings demonstrate a concentration-dependent decline in DIR activity with increasing ceftizoxime concentrations, culminating in complete suppression at 64 μg/L. Polymyxin disrupts the cell membrane, causing structural damage that subsequently impairs the electron transport chain (ETC), leading to a reversible reduction in DIR activity. In contrast, ofloxacin and tetracycline directly down-regulated genes associated with electron production and transfer, thereby suppressing both electron transport system activity and the synthesis of NADH dehydrogenase and c-type cytochromes. This irreversibly disrupts ETC function, blocking S. oneidensis MR-1 from conducting EET and impairing DIR activity. This finding reveals antibiotic-induced alterations in microbial iron metabolism and provides new insights into their potential impact on the environmental iron cycling.

Novel tacrine-based multi-target directed Ligands: Enhancing cholinesterase inhibition, NMDA receptor antagonism, and CNS bioavailability for Alzheimer's disease treatment

Alzheimer's disease (AD) is a multifaceted neurodegenerative disorder for which current treatments provide only symptomatic relief, primarily through cholinesterase (ChE) inhibition and N-methyl-d-aspartate receptor (NMDAR) antagonism. To improve therapeutic efficacy and safety, we designed and synthesized 16 novel tacrine derivatives modified at position 7 with various (hetero)aryl groups or deuterium substitution. Initially, in silico screening predicted favorable CNS permeability and oral bioavailability. Subsequent in vitro evaluations demonstrated significant inhibitory potency against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), with derivatives 5i and 5m displaying particularly promising profiles. Metabolic stability assessed using human liver microsomes revealed enhanced stability for compound 5e, whereas 5i and 5m underwent rapid metabolism. Notably, compound 7 showed improved metabolic stability attributed to deuterium incorporation. The newly synthesized compounds were further tested for antagonistic activity on the GluN1/GluN2B subtype of NMDAR, with compound 5m exhibiting the most potent and voltage-independent inhibition. The ability of these compounds to permeate the blood-brain barrier (BBB) was confirmed through in vitro PAMPA assays. In preliminary hepatotoxicity screening (HepG2 cells), most derivatives exhibited higher cytotoxicity than tacrine, emphasizing the ongoing challenge in hepatotoxicity management. Based on its overall favorable profile, compound 5m advanced to in vivo pharmacokinetic studies in mice, demonstrating efficient CNS penetration, with brain concentrations exceeding plasma levels (brain-to-plasma ratio 2.36), indicating active transport across the BBB. These findings highlight compound 5m as a promising tacrine-based multi-target-directed ligand, supporting further preclinical development as a potential therapeutic candidate for AD.

Phytoflavonoids as alternative therapeutic effect for melanoma: Integrative Network pharmacology, molecular dynamics and drug-likeness profiling for lead discovery

Melanoma, an aggressive skin cancer, poses significant therapeutic challenges due to its resistance to conventional therapies and high metastatic potential. From this perspective, phytoflavonoids from different medicinal and aromatic plants gained attention due to their diverse multimodal anticancer effects with higher antioxidant and anti-inflammatory properties. This study explores phytoflavonoid potency against melanoma via a computer-aided drug design (CADD) platform. Using the core moiety of flavonoids (flavan), four most putative targets, such as cyclin-dependent kinases 1 and 5 (CDK1, CDK5), cell division cycles 25B and 225 C (CDC25B, and CDC225C), have been identified through a network pharmacology approach using TNMplot datasets (GenChip and RNA sequence). Further, 44 phytoflavonoids were selected from extensive literature, and molecular docking studies were carried out against four targets along with standard drugs using AutoDock 4.2 software. Subsequently, physicochemical, toxicity, pharmacokinetics, and drug-ability profiles of phytoflavonoids were predicted. Based on potency and drug-ability, we have selected 'CDK1-naringenin' with the standard drug complex, 'CDK1-dinaciclib,' for molecular dynamic simulation at 100 nanoseconds using GROMACS 2020 software. Based on potency (average docking score: 8.35 kcal/mol.), physicochemical properties (obeyed Lipinski rule of five), toxicity (class-IV), fifty percent lethal dose (2000 mg/kg), bioavailability (0.55), drug-likeness score (0.82), along with ideal pharmacokinetics profiles and higher protein-ligand stability, naringenin is considered as a potential and non-toxic anticancer candidate to be used for melanoma as alternative or complementary agent. The integrative and systematic analyses not only highlight the potential of phytoflavonoids but also select the potential lead from the library within limited resources to accelerate the current anticancer drug discovery process.

Pro-apoptotic and mitochondria-disrupting effects of 4-methylthiazole in K562 leukemia cells: A mechanistic investigation

Thiazole derivatives have garnered attention for their anticancer potential. This study investigates the antileukemic effects of 4-methylthiazole on K562 chronic myeloid leukemia (CML) cells, focusing on apoptosis induction and mitochondrial dysfunction. Cell viability was assessed using MTS assays; apoptosis and necrosis were analyzed via Annexin V/PI staining and flow cytometry; mitochondrial membrane potential changes were evaluated with JC-1 dye; gene expression levels were measured by qRT-PCR; and levels of apoptosis- and cytokine-related proteins were quantified using ELISA. Treatment with 4-methylthiazole led to selective cytotoxicity in K562 cells while sparing healthy peripheral blood mononuclear cells (PBMNCs). Apoptotic induction was evidenced by Caspase-3 (CASP-3) activation, Cytochrome-C (CYT-C), release, and mitochondrial depolarization. Gene expression analysis showed upregulation of pro-apoptotic markers such as TP53 (tumor suppressor protein 53), BAX and BAK (pro-apoptotic Bcl-2 family proteins), while upregulation of CASP3 (caspase-3) expression was not statistically significant. Conversely, levels of GPX4 (glutathione peroxidase 4, involved in oxidative stress protection) remained unchanged, indicating an apoptosis mechanism independent of oxidative stress. Additionally, SEMA3A (Semaphorin 3 A, involved in tumor progression and cell signaling) was significantly downregulated. Cytokine profiling revealed a dose-dependent modulation of IL-6, while TNF-α and IL-10 levels remained unaffected. These findings suggest that 4-methylthiazole induces apoptosis through mitochondrial pathways, affects cytokine signaling, and selectively targets leukemia cells, supporting its potential as a therapeutic candidate for CML treatment.

The potential of metal-organic framework MIL-101(Al)-NH2 in the forefront of antiviral protection of cells via interaction with SARS-CoV-2 spike RBD protein and their antibacterial action mediated with hypericin and photodynamic treatment

The global pandemic of SARS-CoV-2 has highlighted the necessity for innovative therapeutic solutions. This research presents a new formulation utilising the metal-organic framework MIL-101(Al)-NH2, which is loaded with hypericin, aimed at addressing viral and bacterial challenges. Hypericin, recognised for its antiviral and antibacterial efficacy, was encapsulated to mitigate its hydrophobicity, improve bioavailability, and utilise its photodynamic characteristics. The MIL-101(Al)-NH2 Hyp complex was synthesised, characterised, and evaluated for its biological applications for the first time. The main objective of this study was to demonstrate the multimodal potential of such a construct, in particular the effect on SARS-CoV-2 protein levels and its interaction with cells. Both in vitro and in vivo experiments demonstrated the effective transport of hypericin to cells that express ACE2 receptors, thereby mimicking mechanisms of viral entry. In addition, hypericin found in the mitochondria showed selective phototoxicity when activated by light, leading to a decrease in the metabolic activity of glioblastoma cells. Importantly, the complex also showed antibacterial efficacy by selectively targeting Gram-positive Staphylococcus epidermidis compared to Gram-negative Escherichia coli under photodynamic therapy (PDT) conditions. To our knowledge, this study was the first to demonstrate the interaction between hypericin, MIL-101(Al)-NH2 and the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein, which inhibits cellular uptake and colocalises with ACE2-expressing cells. Therefore, the dual functionality of the complex - targeting the viral RBD and the antibacterial effect via PDT - emphasises its potential to mitigate complications of viral infections, such as secondary bacterial infections. In summary, these results suggest that MIL-101(Al)-NH2 Hyp is a promising multifunctional therapeutic agent for antiviral and antibacterial applications, potentially contributing to the improvement of COVID-19 treatment protocols and the treatment of co-infections.

Structural studies on ribosomes of differentially macrolide-resistant Staphylococcus aureus strains

Antimicrobial resistance is a major global health challenge, diminishing the efficacy of many antibiotics, including macrolides. In Staphylococcus aureus, an opportunistic pathogen, macrolide resistance is primarily mediated by Erm-family methyltransferases, which mono- or dimethylate A2058 in the 23S ribosomal RNA, reducing drug binding. Although macrolide-ribosome interactions have been characterized in nonpathogenic species, their structural basis in clinically relevant pathogens remains limited. In this study, we investigate the impact of ermB-mediated resistance on drug binding by analyzing ribosomes from S. aureus strains with varying levels of ermB expression and activity. Using cryo-electron microscopy, we determined the high-resolution structures of solithromycin-bound ribosomes, including those with dimethylated A2058. Our structural analysis reveals the specific interactions that enable solithromycin binding despite double methylation and resistance, as corroborated by microbiological and biochemical data, suggesting that further optimization of ketolide-ribosome interactions could enhance macrolide efficacy against resistant S. aureus strains.

Tiny but mighty! N,N-dimethyl-4-(5-nitrothiophen-2-yl)aniline, a push-pull fluorescent dye for lipid droplet imaging

Lipid droplets (LDs) are ubiquitous cellular organelles with a neutral lipid core containing triacylglycerols and cholesteryl esters surrounded by phospholipids. Recent findings indicate that LDs are intricately linked to diseases, such as cancer and neurological disorders, in addition to their roles in cellular senescence and immune responses. Herein, we describe a simple yet robust push-pull molecule, N,N-dimethyl-4-(5-nitrothiophen-2-yl)aniline (NiTA), as a versatile LD fluorescent probe. NiTA showed an absorption spectrum with a substantial bathochromic shift and a fluorescence spectrum with excellent solvatochromism. Leveraging the remarkable photophysical features of NiTA, we stained LDs in major immune cells, including T and B cells, and macrophages, and monitored the changes in LDs under oxidative and starvation conditions. Furthermore, we demonstrated the applicability of NiTA for visualizing the organization of medaka fish (Oryzias latipes) embryos during development. We expect the small yet powerful NiTA to be utilized in various applications, including fluorescence mapping to observe LD numbers, morphology, and polarity changes in animals and cells.

Structural optimization and pharmacological evaluation of diphenyl amine esters as anti-hepatocellular carcinoma agents by targeting TAR RNA-binding protein 2

Hepatocellular Carcinoma (HCC), a leading cause of cancer-related death in the world, urgently requires novel therapeutic strategies and drug targets. The TRBP-Dicer complex plays a critical role in miRNA biosynthesis, which can be regulated by small molecules to exert anti-cancer effects. This study presented the structural modification of the natural product (-)-Gomisin M1(GM), resulting in the synthesis of 37 derivatives with a diphenyl amine ester scaffold. Several of these derivatives exhibited enhanced modulation of miRNA biogenesis compared to GM. Notably, derivative 13j displayed improved binding affinity to TRBP and greater efficacy in modulating miRNA biosynthesis, as well as anti-HCC activity in vitro and in vivo. Further investigation revealed that 13j induced apoptosis and pyroptosis while inhibiting the epithelial-to-mesenchymal transition process in HCC cells. In terms of druggability, 13j possesses favorable drug-likeness and a promising safety profile. These findings provide a promising scaffold with potent activity and low toxicity, offering a foundation for the development of miRNA-based therapeutic strategies for HCC.

Silaproline-bearing nirmatrelvir derivatives are potent inhibitors of the SARS-CoV-2 main protease highlighting the value of silicon-derivatives in structure-activity-relationship studies

Nirmatrelvir is a substrate-related inhibitor of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) main protease (Mpro) that is clinically used in combination with ritonavir to treat COVID-19. Derivatives of nirmatrelvir, modified at the substrate P2-equivalent position, have been developed to fine-tune inhibitor properties and are now in clinical use. We report the synthesis of nirmatrelvir derivatives with a (R)-4,4-dimethyl-4-silaproline (silaproline) group at the P2-equivalent position. Mass spectrometry (MS)-based assays demonstrate that silaproline-bearing nirmatrelvir derivatives efficiently inhibit isolated recombinant Mpro, albeit with reduced potency compared to nirmatrelvir. Investigations with SARS-CoV-2 infected VeroE6 cells reveal that the silaproline-bearing inhibitors with a CF3 group at the P4-equivalent position inhibit viral progression, implying that incorporating silicon atoms into Mpro inhibitors can yield in vivo active inhibitors with appropriate optimization. MS and crystallographic studies show that the nucleophilic active site cysteine residue of Mpro (Cys145) reacts with the nitrile group of the silaproline-bearing inhibitors. Substituting the electrophilic nitrile group for a non-activated terminal alkyne shifts the inhibition mode from reversible covalent inhibition to irreversible covalent inhibition. One of the two prochiral silaproline methyl groups occupies space in the S2 pocket that is unoccupied in Mpro:nirmatrelvir complex structures, highlighting the value of sila-derivatives in structure-activity-relationship (SAR) studies. The combined results highlight the potential of silicon-containing molecules for inhibition of Mpro and, by implication, other nucleophilic cysteine enzymes.

Discovery of a first-in-class protein arginine methyltransferase 1 (PRMT1) degrader for nonenzymatic functions studies

Among the type I Protein Arginine Methyltransferases (PRMTs), PRMT1 plays a predominant part in catalyzing asymmetric dimethylation of arginine residues on histone or nonhistone substrates. PRMT1 level is abnormally elevated in numerous cancer cell types and inflammation diseases. Compared to the enzymatic functions of PRMT1, its nonenzymatic functions are shortly investigated in diseases. Previous study has confirmed that the stability of orphan receptor TR3, a binding partner of PRMT1, is closely regulated by PRMT1, but the effect is independent of PRMT1's methyltransferase activity, but depends on the physical binding of PRMT1. To date, multiple inhibitors targeting methyltransferase enzymatic activity of PRMT1 are developed, but all of them lack selectivity for PRMT1. Among them, only GSK3368715 advanced to clinical trials but was discontinued in phase I due to inadequate efficacy and thrombosis toxicity. Currently, small molecule degraders are gaining significant attention due to their advantages in efficacy and selectivity in therapeutic applications. Presumably, a potent and selective PRMT1 degrader could serve as a valuable alternative in the treatment of PRMT1-driven diseases and act as an instrumental tool in uncovering additional nonenzymatic functions of PRMT1. To date, however, the development of a PRMT1 degrader remains a challenge, with no such agents reported. In this study, we present the design, synthesis and characterization of CM112 (compound 12), a first-in-class PRMT1 degrader, designed by tethering adamantane to MS023, a type I PRMTs pan inhibitor, via a 5-PEG linker. CM112 demonstrates a concentration- and time-dependent ability to induce PRMT1 degradation in various solid cancer cell lines. Additionally, CM112 shows high selectivity for PRMT1 degradation, without causing degradation of other type I PRMTs (PRMT3/4/6), although it retains potent inhibitory effects on their enzymatic activity. Pharmacokinetics studies indicated that CM112 possesses favorable bioavailability in mice. Notably, as anticipated, CM112 could target PRMT1's nonenzymatic function by downregulating the stability of the orphan receptor TR3, an effect not observed with the PRMT1 inhibitor MS023, that is in consistence with the previous findings. Taken together, CM112 represents a valuable tool for elucidating the unknown, methyltransferase-independent roles of PRMT1 in disease progression and pave the way for developing more potent and drug like PRMT1 degraders in future.

Towards new antibiotics: P. aeruginosa FabF ligands discovered by crystallographic fragment screening followed by hit expansion

There is an urgent need for new antibiotics. FabF (3-oxoacyl-[acyl-carrier-protein] synthase 2), which catalyses the rate limiting condensation reaction in the fatty acid synthesis II pathway, is an attractive target. Very few inhibitors of FabF are known and most are derived from natural products. In an effort to further explore the chemical space of FabF ligands, we have carried out fragment screening by X-ray crystallography against an intermediated state-mimicking variant of P. aeruginosa FabF (PaFabF C164Q). This screen has resulted in 48 hits out of which 16 bind in or close to the malonyl-CoA or fatty acid binding site or an adjacent dimer interface. None of the closer investigated fragments were active in a binding assay, but the same was the case for fragments derived from a potent FabF inhibitor. For hit optimization, we focused on the two fragments binding close to the catalytic residues of FabF. Different strategies were followed in the optimization process: exploration of commercially available analogues, fragment merging, virtual screening of a combinatorial make-on-demand space, and design and in-house synthesis of analogues. In total, more than 90 analogues of the hit compounds were explored, and for 10 of those co-crystal structures could be determined. The most potent ligand was discovered using manual structure-based design and has a binding affinity of 65 μM. This data package forms a strong foundation for the development of more potent and diverse FabF inhibitors.

Redesigning oxazolidinones as carbonic anhydrase inhibitors against vancomycin-resistant enterococci

The rise of vancomycin-resistant enterococci (VRE) as a leading cause of hospital-acquired infections underscores the urgent need for new treatment strategies. In fact, resistance has developed not only to vancomycin but also to other clinically used agents, such as daptomycin and linezolid. We propose a novel drug design approach merging tedizolid, a second-generation oxazolidinone used as an unapproved salvage therapy in clinical settings, with carbonic anhydrase inhibitors (CAIs) recently validated as functioning decolonization agents. These sulfonamide derivatives showed potent inhibition of the carbonic anhydrases from Enterococcus faecium, with KI values in the range of 14.6-598 nM and 63.2-798 nM against EfCAα and EfCAγ. Computational simulations elucidated the binding mode of these dual-action antibiotics to the peptidyl transferase center (PTC) of the 50S ribosome subunit and bacterial CAs. A subset of six derivatives showed potent PTC-related anti-enterococcal effects against multidrug-resistant E. faecalis and E. faecium strains with some compounds outperforming both the oxazolidinone and CA inhibitor drugs (MIC values in the range 1-4 μg/mL).

Synthesis, in vitro and in vivo evaluation, and computational modeling analysis of thioxothiazolidine derivatives as highly potent and selective α-amylase inhibitors

Diabetes mellitus is not only a critical health concern in this era but also a major cause of damage to other organs such as eyes, nerves, kidneys, hearts and liver. Inhibiting α-amylase enzyme is considered as one of the key strategies for controlling chronic hyperglycemia. Therefore, the current work focuses on design and discovery of a series of thioxothiazolidine derivatives (5a-u and 6a-g) as selective α-amylase inhibitors. The target compounds were synthesized using the Knoevenagel condensation approach and evaluated for their α-amylase and α-glucosidase inhibitory activities. The in vitro assay results demonstrated that the tested thioxothiazolidine derivatives possess significantly high potency than the standard drug acarbose against α-amylase but were inactive against α-glucosidase. Among them, compound 5r exhibited remarkable inhibitory potential depicting an IC50 value of 0.71 ± 0.01 μM, significantly outperforming acarbose against α-amylase. In vivo results further demonstrated that the treatment of diabetic rats with compound 5r led to a significant reduction in blood glucose level, indicating its effectiveness in managing hyperglycemia. Biochemical profiling of the treated rats revealed favorable outcomes, including improved urea, creatinine, ALT, AST, ALP, and HbA1C values. Furthermore, in vivo testing in diabetic rats also demonstrated that treatment with compound 5r caused significant histopathological improvements in the kidney, liver and pancreas compared to acarbose. The Lineweaver-Burk plot analysis indicated that compound 5r inhibits α-amylase through a mixed type of inhibition mechanism. Furthermore, molecular docking and dynamics simulations confirmed the in vitro findings while pharmacokinetic properties suggested compound 5r as a favorable drug candidate for the treatment of diabetic complications.

Design, synthesis, and biological activity study of 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline derivatives against multidrug resistance in Eca109/VCR cells

The advent of multidrug resistance (MDR) in tumors markedly diminishes the effectiveness of anticancer therapies. P-glycoprotein (P-gp) plays a crucial role in tumor MDR by mediating the efflux of drugs and cytotoxic agents. Presently, small molecule agents targeting P-gp are among the promising therapeutic approaches to counteract MDR. In previous research, our team identified a novel class of P-gp inhibitors featuring a 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline scaffold. To further delineate the structure-activity relationship, this study conducted an extensive structural optimization, synthesizing 42 novel compounds. Evaluation on the drug-resistant cell line Eca109/VCR indicated that the majority of these compounds exhibited remarkable MDR-reversing activity. Notably, the optimized compound 41 demonstrated an outstanding ability to reverse MDR, with a reversal fold of up to 467.7, surpassing the efficacy of the standard third-generation P-gp inhibitor TQ, as evidenced by plate cloning assay and flow cytometry analysis. Subsequent mechanism validation experiments-including western blotting, chemosensitization tests, and fluorescent substrate accumulation assays-complemented by molecular docking studies, confirmed that compound 41 exerts its MDR-reversing effects through P-gp inhibition. This research offers new perspectives for the development of drug sensitizers targeting resistant tumors based on the tetrahydroisoquinoline scaffold.

The Groebke-Blackburn-Bienaymé (GBB) reaction: A powerful tool for generating diverse heterocyclic scaffold libraries in anticancer drug discovery

The Groebke-Blackburn-Bienaymé (GBB) reaction is a versatile multi-component (MCR) synthetic methodology that has transformed anticancer drug discovery by enabling the rapid and efficient generation of diverse heterocyclic scaffolds. These scaffolds, such as imidazo[1,2-a]pyridines, imidazo[1,2-a]pyrimidines, and their derivatives, are highly valuable moieties for targeting critical cancer pathways. The modular nature of the GBB reaction, coupled with post-reaction modifications, allows the design of compounds with tailored structures and enhanced pharmacological properties. GBB-derived compounds exhibit broad anticancer potential by modulating diverse molecular targets. These include protein kinases (e.g. Rock2, Gsk3β, B-Raf), microtubule dynamics via tubulin inhibition, and G-quadruplex DNA stabilization in oncogene promoters (e.g., c-MYC, BCL2), disrupting key mechanisms of tumour progression. Moreover, they target epigenetic regulators such as HDACs, CBP/P300 bromodomains, and BET bromodomains, affecting transcriptional regulation and chromatin remodeling. Immune checkpoints (e.g., PD-1/PD-L1), enzymes such as autotaxin, TDP1, and Hsp90, as well as apoptotic regulators (e.g., Bcl-2, BAG3), are also effectively inhibited. More importantly, these compounds address challenging targets, including KRAS G12C mutations and the menin-MLL interaction, offering solutions to previously "undruggable" pathways. The unparalleled efficiency of GBB reaction and its ability to generate structurally diverse, bioactive compounds spanning multiple oncogenic mechanisms highlights its central role in advancing anticancer drug discovery and its transformative impact on therapeutic innovation.

Mechanisms of NMDA receptor inhibition by vortioxetine - Comparison with fluoxetine

N-methyl-D-aspartate receptors (NMDARs) are involved in the pathophysiology of depression and are inhibited by many antidepressants. In this work, we studied the action of the vortioxetine, a relatively new multitarget antidepressant, on native NMDARs in rat hippocampal CA1 pyramidal neurons and compared it to the action of structurally similar antidepressant fluoxetine. Vortioxetine inhibited these receptors with IC50 value of 11 ± 1 μM at -80 mV holding voltage, being about three-fold more potent than fluoxetine in these conditions. The inhibition by both compounds was not competitive. Both vortioxetine and fluoxetine demonstrated complex voltage dependence with voltage-dependent and voltage-independent components. The voltage-dependent component corresponded to trapping channel block, while the voltage-independent component - to allosteric inhibition. Vortioxetine and fluoxetine were able to inhibit both open and closed NMDAR channels. Thus, NMDARs can be among important targets for vortioxetine or structurally related drugs. In addition, structural similarity of vortioxetine and fluoxetine allows to assume that these compounds may share other molecular targets besides serotonin transporter and NMDARs.

Advances and challenges in immunosuppressive antibody drug conjugates

Since the approval of Mylotarg™ in 2000 for acute myeloid leukemia, antibody-drug conjugates (ADCs) have significantly advanced precision medicine, particularly for oncology applications. ADCs combine an antibody, a linker, and a payload to result in a targeted therapeutic that minimizes toxicity resulting from systemic drug exposure. This review explores the innovative application of ADC technology towards immunosuppressive therapeutics, primarily focusing on antibody-mediated delivery of glucocorticoids (GCs). Despite their potent anti-inflammatory effects, the clinical use of GCs is limited by adverse systemic effects including osteoporosis, high blood sugar, adrenal insufficiency, weight gain, and glaucoma. Therefore, targeted delivery via ADCs presents a promising strategy to enhance therapeutic efficacy while reducing toxicity. Herein, we review the current status of immune-suppressing ADC technology, starting with early investigations of CD163-targeted dexamethasone and moving to the design of ADCs employing next-generation ultra-potent GCs. Additionally, we will discuss the current status of anti-inflammatory ADCs that employ non-glucocorticoid immune-suppressive medications. Throughout, we will highlight preclinical and clinical data that serves to derisk and drive investment in this new therapeutic class. In parallel, we will focus on ADC design principles that illustrate the importance of careful selection of payload, linker, and conjugation technology in this emerging field.

Development of GluN2A NMDA receptor positive allosteric modulators: Recent advances and perspectives

N-methyl-d-aspartate (NMDA) receptors, functioning as glutamate-gated ion channels, mediate the permeation of Ca2+ and are essential for excitatory synaptic transmission and synaptic plasticity within the central nervous system (CNS). During brain development, there is a switch from an early dominance of GluN2B subunit expression to the incorporation of GluN2A subunits at mature synapses. NMDARs hypofunction is implicated in various psychiatric disorders, and activation of NMDARs containing GluN2A has recently attracted attention as a promising therapeutic approach for treating these diseases. This review focuses on the selective positive allosteric modulators (PAMs) that specifically target the ligand-binding domain (LBD) and N-terminal domain (NTD) regions of GluN2A subtype, as well as non-subunit selective PAMs, and discusses their implications in neuropsychiatric diseases such as stroke, depression, Alzheimer's disease, and Huntington's disease.

Prospects of Innovative Therapeutics in Combating the COVID-19 Pandemic

The sudden global crisis of COVID-19, driven by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), demands swift containment measures due to its rapid spread and numerous problematic mutations, which complicate the establishment of herd immunity. With escalating fatalities across various nations no foreseeable end in sight, there is a pressing need to create swiftly deployable, rapid, cost-effective detection, and treatment methods. While various steps are taken to mitigate the transmission and severity of the disease, vaccination is proven throughout mankind history as the best method to acquire immunity and circumvent the spread of infectious diseases. Nonetheless, relying solely on vaccination might not be adequate to match the relentless viral mutations observed in emerging variants of SARS-CoV-2, including alterations to their RBD domain, acquisition of escape mutations, and potential resistance to antibody binding. Beyond the immune system activation achieved through vaccination, it is crucial to develop new medications or treatment methods to either impede the infection or enhance existing treatment modalities. This review emphasizes innovative treatment strategies that aim to directly disrupt the virus's ability to replicate and spread, which could play a role in ending the SARS-CoV-2 pandemic.

Gaudichaudion H inhibits KRAS-mutant pancreatic cancer cell growth through interfering PDEδ-KRAS interaction

KRAS mutation results in higher proliferation rates and miserable prognosis of cancers. Targeting the interaction between KRAS and PDE6D provided an alternative strategy to overcome KRAS-mutant pancreatic cancers. Gaudichaudione H (GH) is a prenylated caged xanthone isolated from Garcinia oligantha. In this work, GH was selected as a potential anti-cancer compound by MTT screening of twelve prenylated xanthonoids from G. oligantha. Further studies demonstrated that GH inhibited proliferation of a panel of cancer cell lines and induced pancreatic cancer cell apoptosis. GH suppressed xenograft tumor growth accompanied with decreased phosphorylation of ERK and AKT. Binding with PDEδ and thus interfering the KRAS-PDEδ interaction was verified as the possible mechanism of GH. These findings implicated GH as a promising candidate for the treatment of pancreatic cancers with KRAS mutation, provided novel insight into the underlying mechanisms of GH-induced anticancer effects.

Targeting DNA repair mechanisms: Spirobenzoxazinone and salicylamide derivatives as novel candidates for PARP-1 inhibition in cancer therapy

Poly(ADP-ribose) polymerase-1 (PARP-1) plays a crucial role in DNA repair, mediating approximately 90 % of ADP-ribosylation processes associated with DNA damage response. Consequently, inhibiting PARP-1 with small molecules represents a promising strategy for cancer therapy. Utilizing a structure-based design and molecular hybridization approach, we developed three novel series of spirobenzoxazinone-piperdine/salicylamide-based derivatives. These compounds were evaluated for their in vitro PARP-1 inhibitory activity, and their structure-activity relationships were analyzed. At 10 µM concentration, derivatives (18a-d) demonstrated nearly complete inhibition, and the spirocyclic derivative (7c) also achieved a considerable inhibitory effect, with IC50 values in the low micromolar range. The most promising compounds (7c, 18a-d) were tested for their antiproliferative activity against six cancer cell lines. Notably, compounds (7c) and (18d) exhibited significant antiproliferative effects against H1299 and FaDu cells, which correlated with their calculated logP values. These compounds were also tested against normal human skin fibroblasts (HSF), revealing a favorable safety profile compared to cancer cells. Basal anti-PARP-1 activity of the most promising compounds was validated in the HCT116 colorectal cancer cell line. Western blot analysis confirmed robust cleavage of PARP-1, indicating enzymatic inhibition and loss of PARP-1 activity. Combining these inhibitors with doxorubicin showed synergistic lethality in colony-formation assay. Finally, a molecular docking study was conducted to examine the binding modes of these compounds within the PARP-1 active site. The results demonstrated binding modes comparable to those of olaparib and other approved PARP-1 inhibitors, maintaining the key interactions necessary for activity. Based on these findings, compounds (7c) and (18d) emerge as promising candidates for further development in targeting anti-cancer drug resistance through PARP-1 inhibition.

Chromium-functionalized metal-organic frameworks as highly sensitive, dual-mode sensors for real time and rapid detection of dopamine

Dopamine (DA): the brain's "feel-good" chemical that keeps us motivated, happy, and ready to take on the world. This essential neurotransmitter is involved in various physiological processes such as motor control, reward, and mood regulation. Dysregulation of DA levels is linked to several neurodegenerative diseases, emphasizing the need for sensitive and accurate detection methods for both diagnostic and therapeutic purposes. Fluorometric sensing presents an appealing, cost-effective approach to detect DA, especially in complex biological fluids. In this study, we report the synthesis and application of chromium-based metal-organic frameworks (MOFs), Cr-IA and Cr-BTC (IA: itaconic acid and BTC: benzene-1,2,4-tricarboxylic acid), as highly sensitive fluorometric sensors for DA detection in bio-fluids. Cr-IA and Cr-BTC MOFs were synthesized using a solvothermal method with their respective ligands and chromium salts, utilizing a mixed solvent system comprising water, ethanol, and dimethylformamide (DMF). Both MOFs were characterized using a variety of techniques, including Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) surface area analysis, powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), zeta potential measurements, and energy-dispersive X-ray spectroscopy (EDS) that provided essential information on the structural integrity, surface morphology, crystallinity, thermal stability, and surface charge properties of the MOFs, confirming the successful synthesis and characterization of both materials. The synthesized MOFs exhibited remarkable fluorometric sensing capabilities for dopamine detection in HEPES buffer, aqueous solution, and human serum, showcasing strong fluorescence response with high sensitivity, selectivity, and stability across a wide pH range. Cr-IA MOF demonstrated a 3.4-fold fluorescence intensity increase in HEPES buffer, while Cr-BTC MOF achieved a 5-fold enhancement. Both MOFs showed low limits of detection, with Cr-IA and Cr-BTC achieving 21 nM and 41 nM in HEPES buffer, and 26 nM and 20 nM in water, respectively. Fluorescence quenching and visible color changes upon dopamine addition enabled real-time and visual detection, while their dose-response behavior in human serum further validated their reliability for bioanalytical applications. Cytotoxicity studies confirmed their biocompatibility, ensuring their safe use in biological systems. These findings establish Cr-IA and Cr-BTC as highly promising materials for diagnostic and therapeutic monitoring, offering potential for clinical diagnostics and broader biomedical applications.