Design, Synthesis, and Characterization of Novel Pyrazole Cross-Linked Chitosan Derivatives Modified with Zinc Oxide Nanoparticles for Boosting Their Anticancer Activity

A new series of chitosan-based pyrazole derivatives was successfully prepared via crosslinking chitosan using either malonopyrazole (MPy-Cs) or thiopyrazole (TPy-Cs). Three derivatives of TPy-Cs were produced based on their content of TPy, namely TPy-Cs1, TPy-Cs2, and TPy-Cs3 of crosslinking degrees of 71, 48, and 29%, respectively. Further, various weight ratios of ZnO nanoparticles were loaded into some of these derivatives to obtain the corresponding ZnONP bio-composites. FTIR, XRD, SEM, and TEM techniques were employed to emphasize the chemical, internal, and morphological structure of these derivatives. Although MPy-Cs derivatives did not show any activity against all the examined cancer cell lines, TPy-Cs derivatives exhibited an appreciable anticancer activity which greatly improved with increasing their TPy content, i.e., from TPy-Cs3 to TPy-Cs1. The TPy-Cs1 displayed IC50 (14.4 μg/mL) against the HN9 cell line that was comparable to the Doxorubicin (DOX) standard drug (12.6 μg/mL). Among all the prepared composites, TPy-Cs3/ZnONPs-5% was the most potent anticancer candidate against all the tested cancer cell lines, although it does not exceed the anticancer activity of DOX. Tpy-Cs2 and its ZnONP composites were safe on normal human skin fibroblast (HSF) cell lines. Thus, the inclusion of both TPy and ZnONPs into the chitosan matrix fostered its anticancer efficiency.

Diamino variants of piperazine-based tissue transglutaminase inhibitors

Tissue transglutaminase (TG2) is a multifunctional protein that can catalyze the cross-linking between proteins, and function as a G-protein. TG2's unregulated behaviour has been associated with fibrosis, celiac disease and cancer metastasis. Recently, small molecule irreversible inhibitors have been designed, bearing an electrophilic warhead that can react with the catalytic cysteine, abolishing TG2's catalytic and G-protein capabilities. Several research groups have converged on inhibitors comprising piperazine scaffolds, but no structure-activity relationships (SAR) of the piperazine core have been reported. In this study we synthesize a series of inhibitors with various diamino linkers, to understand what structural requirements are necessary for the core to help align the terminal acrylamide warhead in the optimal position. Kinetic evaluation using an in vitro biochemical assay provided the kinetic parameters kinact and KI for each inhibitor. This study revealed that adding a methyl group to the piperazine core can improve inhibitor efficiency.

Synthesis and biofilm inhibitory activity of cyclic dinucleotide analogues prepared with macrocyclic ribose-phosphate skeleton

Cyclic diguanosine monophosphate (c-di-GMP) is the key second messenger regulating bacterial biofilm formation related genes. Several c-di-GMP analogues have demonstrated biofilm inhibition activity. In this study, ribose-phosphate macrocyclic skeleton containing 1'-azido groups was constructed, and CDN analogues were prepared via click chemistry. The biofilm formation inhibition activity of the analogues was evaluated, and compound 17 illustrated better activity than c-di-GMP. This high-throughput strategy could be extended to synthesize cyclic analogues for biological research and immunotherapeutic development.

Discovery of novel imidazo[1,2-b]pyridazine derivatives as potent covalent inhibitors of CDK12/13

Triple-negative breast cancer (TNBC) is widely recognized as the most aggressive subtype of breast cancer, and treatment options for patients with TNBC remain highly limited. Recently, cyclin-dependent kinases 12/13 (CDK12/13) have been identified as promising therapeutic targets for TNBC. In our study, we report the design and synthesis of novel imidazo[1,2-b]pyrazine-based covalent inhibitors of CDK12/13, which exhibit potent inhibitory activity against TNBC cells. Among these compounds, compound 24 emerged as the most potent inhibitor, with CDK12 IC50 of 15.5 nM and CDK13 IC50 of 12.2 nM. Compound 24 forms a covalent bond with Cys1039 of CDK12 and effectively suppresses the proliferation of TNBC cell lines MDA-MB-231 and MDA-MB-468, with EC50 values of 5.0 nM and 6.0 nM, respectively. Compound 24 demonstrated superior efficacy to the currently known CDK12/13 covalent inhibitor, THZ531. These findings suggest compound 24 may be a promising lead for developing CDK12/13-targeted therapies for treating TNBC.

Role and mechanisms of m6A demethylases in digestive system tumors

Digestive system tumors are common malignancies in humans, often accompanied by high mortality and poor prognosis. Therefore, intensive research on the pathogenesis of digestive system tumors is imperative. N6-methyladenosine (m6A) is the most common RNA modification in eukaryotes and exerts regulatory effects on RNA expression and metabolism, including splicing, translation, stability, decay, and transport. m6A demethylases belong to the AlkB family of dioxygenases that can catalyze m6A demethylation. Accumulating evidence in recent years has shown that abnormal m6A levels caused by m6A demethylases play crucial roles in different aspects of human cancer development. In this review, we comprehensively summarize the recent findings on the functions and underlying molecular mechanisms of m6A demethylases in cell proliferation, apoptosis, migration, invasion, metastasis, angiogenesis, resistance to chemo- and radiotherapy, and the tumor immune microenvironment (TIME) of digestive system tumors. Furthermore, we discuss the therapeutic potential of targeting these m6A demethylases for treatment.

Targeting cancer-induced skeletal damage: a holistic approach to understanding pathophysiology, mechanisms, and management solutions

Cancer's insidious reach extends far beyond its initial site, particularly manifesting in the skeleton, where it precipitates a spectrum of pathological conditions ranging from bone metastases and cachexia to primary bone cancers. This review highlights the critical impact of cancer on skeletal health, including the development of bone metastases, cachexia, and primary bone cancers, underscoring the importance of understanding the complex interaction between cancer and the bones. It emphasizes the global burden of cancer and its skeletal complications, which severely affect quality of life. The article reviews the prevalence of bone metastases in various cancers, such as breast, prostate, lung, renal cancers, and multiple myeloma, and stresses the need for targeted treatments. It also discusses the mechanisms behind tumor spread to bones and the systemic effects of cancer, including reduced bone mineral density and increased fracture risk, even without direct bone invasion. The challenges posed by primary bone cancers, which are rarer but highly aggressive, are also examined, highlighting the role of genetics and molecular research in treatment development. The review calls for a multidisciplinary approach to manage the severe symptoms of cancer-induced bone damage and explores the potential of personalized medicine to improve treatment outcomes. It concludes by advocating for continued research and collaboration to develop more precise and personalized therapies for cancer-related bone issues, aiming to improve the lives of those affected.

A novel porphyrin-based theranostic agent activated by cysteine over-expressed in cancer cells shows promise for tumour-targeted monitoring and phototherapy

l-Cysteine (Cys) is a tumor-related biomarker. The photo- and Cys-activatable theranostic agent 4 was designed and synthesized based on 5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin (3). Compound 4 exhibited negligible fluorescence and photosensitizing activity in the absence of Cys. However, when activated by Cys, 3 was released, resulting in fluorescence and photosensitization. Moreover, upon irradiation with 660 nm light, 4 displayed selective and effective fluorescence and photo-cytotoxicity exclusively against cancer cells, such as HeLa and A549 cells, which express high levels of Cys. This wavelength of light falls within the phototherapeutic window.

The Druggable Transcriptome Project: From Chemical Probes to Precision Medicines

RNA presents abundant opportunities as a drug target, offering significant potential for small molecule medicine development. The transcriptome, comprising both coding and noncoding RNAs, is a rich area for therapeutic innovation, yet challenges persist in targeting RNA with small molecules. RNA structure can be predicted with or without experimental data, but discrepancies with the actual biological structure can impede progress. Prioritizing RNA targets supported by genetic or evolutionary evidence enhances success. Further, small molecules must demonstrate binding to RNA in cells, not solely in vitro, to validate both the target and compound. Effective small molecule binders modulate functional sites that influence RNA biology, as binding to nonfunctional sites requires recruiting effector mechanisms, for example degradation, to achieve therapeutic outcomes. Addressing these challenges is critical to unlocking RNA's vast potential for small molecule medicines, and a strategic framework is proposed to navigate this promising field, with a focus on targeting human RNAs.

Integrated computational and biosensor-based strategies for the discovery of allosteric SMYD3 ligands using diperodon as a starting point

SMYD3 (SET- and MYND-domain containing protein 3) is an epigenetic enzyme with lysine methyl transferase activity and multiple protein binding partners. It is implicated in cancer development and active site inhibitors with antitumor activity have been developed. We have previously discovered that diperodon is an allosteric SMYD3 ligand and are interested in developing ligands that can interfere with non-catalytic functions of SMYD3, while avoiding conceivable draw-backs of targeting a conserved site in an enzyme with several close family members. Herein, the features of the diperodon site were explored via computational modelling and served as a basis for identifying analogues in commercial compound space, thus avoiding the need for in-house compound synthesis. Time-resolved grating coupled interferometry (GCI) biosensor analysis confirmed that two out of 21 acquired analogues interacted with SMYD3, with similar affinities as diperodon (KD ∼ 180 and 210 vs. ∼200 µM). As a second approach, fragmentation of diperodon followed by growing of fragments identified an additional 11 compounds in commercial compound space. GCI analysis confirmed that N-phenylformamide and three compounds evolved from this fragment interacted with SMYD3. These four ligands varied structurally from diperodon and had higher affinities (KD = 0.4-130 µM) and superior ligand efficiencies. However, all ligands interacted with rapid kinetics and weak affinities, indicating that the site had poor ligandability, possibly a result of its extremely flexible structure. Difficulties in protein production and the overall flexible structure of SMYD3, prevented NMR experiments and X-ray crystallography. Nevertheless, the combination of computational ligand design supported by biosensor-based analyses resulted in new allosteric ligands with minimal resources in a short time.

Genomic characterization of Leishmania (V.) braziliensis associated with antimony therapeutic failure and variable in vitro tolerance to amphotericin B

Leishmaniasis, a vector-borne disease caused by protozoa from the Leishmania genus, presents a wide range of clinical manifestations in humans and varying responses to treatments. The main clinical presentations correspond with visceral leishmaniasis (VL), cutaneous leishmaniasis (CL), and mucosal leishmaniasis (ML). Amphotericin B (AmB) is a second-line therapeutic option in all forms of leishmaniasis with treatment failure or contraindication for Antimony derivates (SbV) therapy and in geographical regions with a high prevalence of SbV-resistant parasites. This study delves into the genomic features of thirteen L. (V.) braziliensis clinical isolates from CL patients who experienced therapeutic failure to SbV treatment. The isolates were categorized based on their AmB in vitro susceptibility in the amastigote stage, the intracellular parasitic form found in the vertebrate host. The whole genome sequences of the isolates were analyzed and compared with the reference genomes of L. (V.) braziliensis (MHOM/BR/75/M2904 and M2903). The average number of heterozygous SNPs in clinical isolates is at least 75% higher than the reference genomes, and the allele dosages suggest an overall ploidy of two, except in chromosome 31. The main mutations associated with AmB resistance previously reported in experimental cell lines from L. (L.) infantum, L. (L.) mexicana, and L. (L.) donovani were not found in this study. However, there were found mutations referred by other authors in parasites resistant to antileishmanial drugs in proteins such as GP63 (leishmanolysin), NADH-ubiquinone oxidoreductase- ESSS subunit- (putative), quinonoid dihydropteridine reductase, 20s proteasome beta 7 subunit- (putative), biopterin transporter- (putative), and common hypothetical proteins. CNV analysis revealed that the isolates most tolerant to AmB present duplications of genomic regions encompassing genes involved in N-Glycan biosynthesis and biopterin/folate transport and metabolism. Therefore, the present study uncovers previously undescribed metabolic pathways that could be involved in the natural AmB tolerance in Leishmania, which need to be functionally evaluated. These findings highlight the need for further drug response studies in field isolates.

Regioselective Hydrocyanation of Internal Alkynes Enabled by a Transition-Metal-Free Dual-Catalytic System

Since its discovery in 1954, the hydrocyanation of multiple carbon-carbon bonds has emerged as a powerful strategy for the synthesis of nitriles. However, the elusive control of selectivity and typical reliance on expensive and toxic transition metal (TM) based catalysts significantly hinder the utility of this process. Here, we report an exclusively regioselective hydrocyanation of unbiased alkynes, driven by base-catalyzed reversible alkyne-allene isomerization and phosphine-catalyzed HCN transfer to the allene. This TM-free, dual-catalytic approach introduces a novel mode of selectivity control via regioselective hydrocyanation of the allene intermediate. The methodology secures a cost-effective access to a broad range of vinyl nitriles (40 examples) with yields up to 97% and Z/E stereoselectivity up to 20:1, including complex natural product derivatives. A comparison with TM-based systems highlighted a 2500-fold cost reduction, as well as the elimination of the troublesome separation of the regioisomers. Mechanistic studies elucidated the reaction pathway, shedding light on the achieved regioselectivity. By altering one catalyst in a dual-catalytic system, we demonstrated the regioselectivity switch, thereby facilitating regiodivergent hydrocyanation (eight examples). In a broader context, this approach offers a foundation for developing the next generation of TM-free strategies for the regioselective hydrofunctionalizations of unbiased alkynes.

Disarming Staphylococcus aureus: Review of Strategies Combating This Resilient Pathogen by Targeting Its Virulence

Staphylococcus aureus is a formidable pathogen notorious for its antibiotic resistance and diverse virulence mechanisms, including toxin production, biofilm formation, and immune evasion. This article explores innovative anti-virulence strategies to disarm S. aureus by targeting critical virulence factors without exerting bactericidal pressure. Key approaches include inhibiting adhesion and biofilm formation, neutralizing toxins, disrupting quorum sensing (e.g., Agr system inhibitors), and blocking iron acquisition pathways. Additionally, interventions targeting two-component regulatory systems are highlighted. While promising, challenges such as strain variability, biofilm resilience, pharmacokinetic limitations, and resistance evolution underscore the need for combination therapies and advanced formulations. Integrating anti-virulence strategies with traditional antibiotics and host-directed therapies offers a sustainable solution to combat multidrug-resistant S. aureus, particularly methicillin-resistant strains (MRSA), and mitigate the global public health crisis.

Biosynthesis and structure assignment of a hydroxylated metabolite of the orexin-1 receptor antagonist JNJ-61393215

JNJ-61393215, a deuterated compound, is a selective OX1R antagonist. In both preclinical and clinical studies, a hydroxylated metabolite designated M54 was observed to be the most abundant metabolite in plasma. Screening of Hypha PolyCYPs®+ kit revealed PolyCYP 152 was the most proficient at producing M54 from JNJ-61393215 and subsequent scale up with PolyCYP 152 provided small but sufficient quantities of M54 for initial structure elucidation by NMR analyses. A microbial biosynthesis, using a Streptomyces strain from which PolyCYP 152 was genetically derived, provided gram quantities of M54. It allowed chemical epimerization of the chiral hydroxylated carbon of M54 and unequivocally established the metabolite's absolute stereo-configuration. The biotransformation provided remarkably efficient methodologies for quick synthesis of the metabolite M54 with stereoselective hydroxylation on the deuterated unique 2-aza-[2.2.1]-bicycle core structure, for which structure assignment via classical synthesis of speculative structures would be challenging and resource-intensive. Moreover, the microbial biosynthesis provided M54 with high purity for ongoing preclinical studies.

Side-Functionalization of Poly(l-methionine) for Ice Control

Controlling ice growth is crucial during the cryopreservation of cells, but the current application of small molecules as cryoprotectants still remains a challenge. Inspired by structures of natural antifreeze (glyco)proteins, in this work, functionalized poly(l-methionine)s (PMets) are synthesized with different side groups including hydroxyl, threonine-mimetic with both methyl and hydroxyl groups (PMet-MOH), zwitterion with carboxyl and sulfonium (PMet-COOH), glycerol, and trehalose pendants. Results suggest that these functionalized PMets tend to self-assemble into 100-300 nm nanoparticles with positive charges in water. The functional structures have a remarkable influence on their ice control properties. It is supposed that PMet-MOH inhibits ice growth possibly through the adsorption mechanism by adjacent methyl and hydroxyl groups, whereas trehalose-tethered PMet can restrict diffusion of water molecules with the strongest ice recrystallization inhibition activity and zwitterionic PMet-COOH promotes ice nucleation obviously. This work offers valuable insight into the development of functional polypeptides as promising biocompatible cryoprotectants.

The Potential Therapeutic Role of Beta-Caryophyllene as a Chemosensitizer and an Inhibitor of Angiogenesis in Cancer

The natural, highly lipophilic bicyclic sesquiterpenes, Beta-Caryophyllene (BCP), was highlighted in several recent preclinical studies to enhance chemo-sensitization in chemo-resistant tumors and to efficiently inhibit angiogenesis and cancer cells' ability to invade and metastasize. Previous studies have researched the reasons for the synergistic effect of Beta-Caryophyllene in combination therapy and its role as a chemosensitizer and an inhibitor of angiogenesis through investigating the involved mechanisms and signaling molecules. These include the lipophilic nature of BCP, the selective interaction of BCP with CB2, the binding affinity of BCP to the receptor binding sites at the angiogenic vascular endothelial growth factor, and the upstream effect on JAK1/STAT3 pathway and other signaling pathways. Herein, the BCP role in enhancing chemo-sensitization of chemo-resistant tumors and in inhibiting angiogenesis and cancer cells' ability to invade and metastasize are highlighted. Beta-Caryophyllene appears to be a promising candidate in treating cancer when co-supplemented with drugs such as cisplatin, gemcitabine and sorafenib. Clinical trials are needed to validate the potential therapeutic effect of BCP as a co-supplementary drug in cancer therapy, helping to sensitize cancer response to drugs, modulating signaling pathways, and lowering the drugs' doses besides working as anti-angiogenetic drug.

The Role of ETS2 in Macrophage Inflammation

Autoimmune and inflammatory diseases are rising globally yet widely effective therapies remain elusive. Most treatments have limited efficacy, significant potential side effects, or eventually lose response, underscoring the urgent need for new therapeutic approaches. We recently discovered that ETS2, a transcription factor, functions as a master regulator of macrophage-driven inflammation-and is causally linked to the pathogenesis of multiple inflammatory diseases via human genetics. The pleotropic inflammatory effects of ETS2 included upregulation of many cytokines that are individually targeted by current disease therapies, including TNFα, IL-23, IL1β, and TNF-like ligand 1A signaling. With the move toward combination treatment-to maximize efficacy-targeting ETS2 presents a unique opportunity to potentially induce a broad therapeutic effect. However, there will be multiple challenges to overcome since direct ETS2 inhibition is unlikely to be feasible. Here, we discuss these challenges and other unanswered questions about the central role that ETS2 plays in macrophage inflammation.

Beyond-Rule-of-Five Compounds Are Not Different: In Vitro-In Vivo Extrapolation of Female CD-1 Mouse Clearance Based on Merck Healthcare KGaA Compound Set

Background: Extrapolation of intrinsic clearance from in vitro systems such as liver microsomes or hepatocytes is an established approach to predict clearance in preclinical species and in humans. A common discussion in the literature is whether the predictive accuracy of such extrapolations is influenced by the chemotype and whether these methods are also applicable to compounds studied in early drug discovery programs. Compounds in such programs are frequently lipophilic and show low solubility and low free fraction in plasma, which may pose challenges to the extrapolation of clearance different from those of the final clinical candidates. A similar discussion has been raised about compounds residing beyond the traditional small-molecule property space, such as PROTACs© and other molecules incompatible with Lipinski's rule-of-five. Methods: To further enlighten the field on these matters, we present a study comparing the predictive accuracy between mouse hepatocytes and microsomes for a set of molecules (N = 211) from the Merck Healthcare drug discovery pipeline. This set was dominated by compounds belonging to class 2 and 4 of the extended clearance classification systems (ECCS). It contained a similar proportion of molecules compliant with the Lipinski rule-of-five (N = 127) and molecules lacking such compliance (N = 84). Results: This study showed no or little differences in predictive accuracy nor bias between the two groups, with an average fold error close to 1, an absolute average fold error of just over 2, and around 50% being within 2-fold and >90% being within 5-fold of the predicted unbound clearance in both in vitro systems. Furthermore, no significant differences in accuracy were observed for compounds with an extremely low free fraction (down to 0.05%) in plasma. Conclusions: The accuracy of in vitro-in vivo extrapolation of female CD-1 mouse clearance was not affected by the physicochemical properties.

Green Light Activated Dual-Action Pt(IV) Prodrug with Enhanced PDT Activity

Light induced release of cisplatin from Pt(IV) prodrugs is a promising tool for precise spatiotemporal control over the antiproliferative activity of Pt-based chemotherapeutic drugs. A combination of light-controlled chemotherapy (PACT) and photodynamic therapy (PDT) in one molecule has the potential to overcome crucial drawbacks of both Pt-based chemotherapy and PDT via a synergetic effect. Herein we report green-light-activated Pt(IV) prodrug GreenPt with BODIPY-based photosentitizer in the axial position with an incredible high light response and singlet oxygen generation ability. GreenPt demonstrated the ability to release cisplatin under low-dose green light irradiation up to 1 J/cm2. The investigation of the photoreduction mechanism of GreenPt prodrug using DFT modeling and ΔG0 PET estimation revealed that the anion-radical formation and substituent photoinduced electron transfer from the triplet excited state of the BODIPY axial ligand to the Pt(IV) center is the key step in the light-induced release of cisplatin. Green-light-activated BODIPY-based photosentitizers 5 and 8 demonstrated outstanding photosensitizing properties with an extraordinary phototoxicity index (PI)>1300. GreenPt prodrug demonstrated gradual intracellular accumulation and light-induced phototoxicity with PI>100, thus demonstrating dual action through light-controlled release of both cisplatin and a potent BODIPY-based photosensitizer.

Understanding the Link Between Sterol Regulatory Element Binding Protein (SREBPs) and Metabolic Dysfunction Associated Steatotic Liver Disease (MASLD)

PURPOSE OF THE REVIEW

This review aims to summarize the current scientific understanding on the complex interplay between sterol regulatory element-binding proteins (SREBPs) and metabolic dysfunction associated steatotic liver disease (MASLD) by critically examining a few significant molecular pathways. Additionally, the review explores the potential of both natural and synthetic SREBP inhibitors as promising therapeutic candidates for MASLD.

RECENT FINDINGS

SREBPs are central regulators of lipid homeostasis, with SREBP-1c primarily controlling fatty acid synthesis and SREBP-2 regulating cholesterol metabolism. Dysregulation of SREBP activity, often triggered by excessive caloric intake, insulin resistance, or endoplasmic reticulum (ER) stress, contributes to the development of metabolic syndrome and MASLD. SREBP-1c overexpression leads to increased de novo lipogenesis (DNL), hepatic lipid accumulation, and insulin resistance, while SREBP-2 modulates cholesterol metabolism via miRNA-33 and ABCA1 regulation leading to the pathogenesis of MASLD. The PI3K-Akt-mTORC1 pathway plays a critical role in SREBP activation, linking nutrient availability to lipid synthesis. Synthetic SREBP inhibitors, such as fatostatin and 25-hydroxycholesterol, and natural compounds, including kaempferol and resveratrol, show promise in modulating SREBP activity in vivo.

CONCLUSION

While targeting SREBP pathways presents a promising avenue for mitigating MASLD, further scientific investigation is imperative to identify and validate potential molecular targets. Although current studies on synthetic and natural SREBP inhibitors demonstrate encouraging results, rigorous pre-clinical and clinical research is warranted to translate these findings into effective MASLD treatments.

Development of an Environmentally Responsive Fluorescent Ligand for Vitamin D Receptor

Vitamin D receptor (VDR) plays a critical role in regulating multiple biological processes, including bone metabolism and cell differentiation, by mediating transcriptional activation in response to ligand binding. We have constructed an environmentally fluorescent probe 2 for VDR to facilitate real-time observation of its ligand-dependent conformational changes in living cells. This probe 2 was synthesized by introducing a dansyl fluorophore via an ethynyl group at the C11 position of 1α,25(OH)₂D₃. Probe 2 exhibited strong environmentally responsive fluorescence, showing increased intensity and a blue shift of the peak wavelength upon binding to VDR due to the increased hydrophobicity of the environment.

Revitalizing Antibiotics with Macromolecular Engineering: Tackling Gram-Negative Superbugs and Mixed Species Bacterial Biofilm Infections In Vivo

The escalating prevalence of multidrug-resistant Gram-negative pathogens, coupled with dwindling antibiotic development, has created a critical void in the clinical pipeline. This alarming issue is exacerbated by the formation of biofilms by these superbugs and their frequent coexistence in mixed-species biofilms, conferring extreme antibiotic tolerance. Herein, we present an amphiphilic cationic macromolecule, ACM-AHex, as an innovative antibiotic adjuvant to rejuvenate and repurpose resistant antibiotics, for instance, rifampicin, fusidic acid, erythromycin, and chloramphenicol. ACM-AHex mildly perturbs the bacterial membrane, enhancing antibiotic permeability, hampers efflux machinery, and produces reactive oxygen species, resulting in a remarkable 64-1024-fold potentiation in antibacterial activity. The macromolecule reduces bacterial virulence and macromolecule-drug cocktail significantly eradicate both mono- and multispecies bacterial biofilms, achieving >99.9% bacterial reduction in the murine biofilm infection model. Demonstrating potent biocompatibility across multiple administration routes, ACM-AHex offers a promising strategy to restore obsolete antibiotics and combat recalcitrant Gram-negative biofilm-associated infections, advocating for further clinical evaluation as a next-generation macromolecular antibiotic adjuvant.

Stacking Interactions of Druglike Heterocycles with Nucleobases

Stacking interactions contribute significantly to the interaction of small molecules with RNA, and harnessing the power of these interactions will likely prove important in the development of RNA-targeting inhibitors. To this end, we present a comprehensive computational analysis of stacking interactions between a set of 54 druglike heterocycles and the natural nucleobases. We first show that heterocycle choice can tune the strength of stacking interactions with nucleobases over a large range and that heterocycles favor stacked geometries that cluster around a discrete set of stacking loci characteristic of each nucleobase. Symmetry-adapted perturbation theory results indicate that the strengths of these interactions are modulated primarily by electrostatic and dispersion effects. Based on this, we present a multivariate predictive model of the maximum strength of stacking interactions between a given heterocycle and nucleobase that depends on molecular descriptors derived from the electrostatic potential. These descriptors can be readily computed using density functional theory or predicted directly from atom connectivity (e.g., SMILES). This model is used to predict the maximum possible stacking interactions of a set of 1854 druglike heterocycles with the natural nucleobases. Finally, we show that trivial modifications of standard (fixed-charge) molecular mechanics force fields reduce errors in predicted stacking interaction energies from around 2 kcal/mol to below 1 kcal/mol, providing a pragmatic means of predicting more reliable stacking interaction energies using existing computational workflows. We also analyze the stacking interactions between ribocil and a bacterial riboswitch, showing that two of the three aromatic heterocyclic components engage in near-optimal stacking interactions with binding site nucleobases.

Main methods and tools for peptide development based on protein-protein interactions (PPIs)

Protein-protein interactions (PPIs) regulate essential physiological and pathological processes. Due to their large and shallow binding surfaces, PPIs are often considered challenging drug targets for small molecules. Peptides offer a viable alternative, as they can bind these targets, acting as regulators or mimicking interaction partners. This review focuses on competitive peptides, a class of orthosteric modulators that disrupt PPI formation. We provide a concise yet comprehensive overview of recent advancements in in-silico peptide design, highlighting computational strategies that have improved the efficiency and accuracy of PPI-targeting peptides. Additionally, we examine cutting-edge experimental methods for evaluating PPI-based peptides. By exploring the interplay between computational design and experimental validation, this review presents a structured framework for developing effective peptide therapeutics targeting PPIs in various diseases.

Potentiating Antibody-Dependent Cellular Cytotoxicity in Triple-Negative Breast Cancer via the Humanized Anti-CD147 Antibody

BACKGROUND

Triple-negative breast cancer (TNBC) is an aggressive subtype with high metastatic potential, poor prognosis, and the absence of estrogen receptors, progesterone receptors, and human epidermal growth factor receptor 2 (HER2). The lack of these receptors limits the standard treatments, such as hormone therapies and HER2-targeted antibodies like trastuzumab. These challenges highlight the critical need for novel therapeutic strategies. CD147, a transmembrane glycoprotein overexpressed in TNBC, promotes tumor progression, metastasis, and chemoresistance, making it a promising therapeutic target. This study evaluates the antibody-dependent cellular cytotoxicity (ADCC) of HuM6-1B9, a humanized anti-CD147 antibody, against MDA-MB-231 cells, a TNBC model.

METHODS

CFSE-labelled MDA-MB-231 cells were co-cultured with PBMCs as effector cells (E:T ratio 80:1) in the presence of HuM6-1B9 and incubated for 4 h. Cells were then collected and stained with PI, and CFSE+/PI+ dead target cells were analyzed by flow cytometry.

RESULTS

Co-culturing MDA-MB-231 cells with peripheral blood mononuclear cells (PBMCs) in the presence of HuM6-1B9 demonstrated effective ADCC induction without direct cytotoxicity. HuM6-1B9 induced 54.01% cancer cell death via ADCC, significantly outperforming trastuzumab (26.14%) while sparing PBMCs.

CONCLUSION

These findings support HuM6-1B9 as a prospective TNBC therapeutic and warrant further investigation into its clinical potential.

Structural Insights into Bortezomib-Induced Activation of the Caseinolytic Chaperone-Protease System in Mycobacterium tuberculosis

The caseinolytic protease (Clp) system has recently emerged as a promising anti-tuberculosis target. The anti-cancer drug bortezomib exhibits potent anti-mycobacterial activity and binds to Mycobacterium tuberculosis (Mtb) Clp protease complexes. We determine cryo-EM structures of Mtb ClpP1P2, ClpC1P1P2 and ClpXP1P2 complexes bound to bortezomib in different conformations. Structural and biochemical data indicate that sub-stoichiometric binding by bortezomib to the protease active sites orthosterically activates the MtbClpP1P2 complex. Bortezomib activation of MtbClpP1P2 induces structural changes promoting the recruitment of the chaperone-unfoldases, MtbClpC1 or MtbClpX, facilitating holoenzyme formation. The structures of the MtbClpC1P1P2 holoenzyme indicate that MtbClpC1 motion, induced by ATP rebinding at the MtbClpC1 spiral seam, translocates the substrate. In the MtbClpXP1P2 holoenzyme structure, we identify a specialized substrate channel gating mechanism involving the MtbClpX pore-2 loop and MtbClpP2 N-terminal domains. Our results provide insights into the intricate regulation of the Mtb Clp system and suggest that bortezomib can disrupt this regulation by sub-stoichiometric binding at the Mtb Clp protease sites.

Recent Advances in the Development of Sigma Receptor (Radio)Ligands and Their Application in Tumors

Cancer ranks among the top triumvirate leading causes of human deaths worldwide. The pathological mechanisms are notably intricate, demonstrating proliferative and metastatic capabilities, which complicate therapeutic interventions. The sigma-1 receptor (σ1R) plays a crucial role in tumor survival and migration, while the sigma-2 receptor (σ2R) is intimately associated with tumor proliferation. This review encapsulated the investigation concerning σ1R and σ2R in neoplasms and rigorously summarized the ligands and radio-ligands development and their tumor applications, such as antitumor cell proliferation and PET/SPECT imaging in tumors. A comprehensive classification discussion was undertaken regarding the chemical structures and emphasized the possibility of dual/multitargeted ligands. Ultimately, we discussed the effects of chiral structures and the pharmacological characteristics of ligands on affinity and pharmacokinetic features in vivo, particularly concerning radiopharmaceuticals. This review functions as a beneficial resource, fostering ligand deployment and stimulating the generation of innovative ideas for developing innovative radiopharmaceuticals.

Searching for New Gold(I)-Based Complexes as Anticancer and/or Antiviral Agents

Approaches capable of simultaneously treating cancer and protecting susceptible patients from lethal infections are highly desirable, although they prove challenging. Taking inspiration from the well-known anticancer platinum complexes, successive studies about the complexation of organic compounds with other late transition metals, such as silver, gold, palladium, rhodium, ruthenium, iridium, and osmium, have led to remarkable anticancer activities. Among the numerous chemical moieties studied, N-heterocyclic carbenes (NHCs) have revealed very attractive activities due to their favorable chemical properties. Specifically, gold-NHC complexes emerged as some of the most active complexes acting as antitumor agents. On the other hand, some recent studies have highlighted the involvement of these complexes in antiviral research as well. The well-known gold-based, orally available complex auranofin approved by the Food and Drug Administration (FDA) for the treatment of rheumatoid arthritis has been suggested as a repositioned drug for both cancer and viral infections. In the era of the COVID-19 pandemic, the most interesting goal could be the discovery of gold-NHC complexes as dual antiviral and anticancer agents. In this review, the most recent studies regarding the anticancer and antiviral activities of gold(I)-NHC complexes will be analyzed and discussed, offering an interesting insight into the research in this field.

Nature-Inspired Anticancer Agents: The Synergy of Phytochemicals and Synthetic Analogs (2019-2024)

Cancer remains one of the most formidable global health challenges, marked by uncontrolled cell growth and division. Despite medical advancements, traditional treatments often fall short due to issues of specificity, resistance, and toxicity, compounded by the complex pathophysiology of the disease. In this context, natural products, particularly phytochemicals, have emerged as promising anticancer agents. Compounds such as vinca alkaloids, curcuminoids, flavonoids, terpenoids, polyphenols, and others have demonstrated potent anticancer properties by targeting key molecular pathways, including protein kinases, aromatase, EGFR, TNF-α, HER-2, and caspases. This review explores recent advancements in phytochemical research from 2019 to 2024 and includes natural product-inspired synthetic derivatives with enhanced therapeutic potential. A comprehensive literature survey was conducted using databases such as PubMed, Scopus, Web of Science, and Google Scholar. Keywords used included "phytochemicals," "natural products," "cancer," "anticancer agents," "kinase inhibitors," "EGFR," "HER2," "aromatase," and "synthetic analogs." Articles were selected based on relevance, recency, and impact in the field. By providing mechanistic insights and highlighting novel compounds with clinical relevance, this work underscores the critical role of phytochemicals and their derivatives in addressing current therapeutic limitations and shaping future cancer treatments.

Recommended Tool Compounds: Thienotriazolodiazepines-Derivatized Chemical Probes to Target BET Bromodomains

Thienotriazolodiazepines, including (+)-JQ1 (4), are well-known inhibitors of the bromodomain (BD) and extra-terminal domain (BET) family of proteins. Despite the suboptimal physicochemical properties as a drug candidate, such as poor solubility and half-life, (+)-JQ1 (4) has proven as an effective chemical probe with high target potency and selectivity. (+)-JQ1 (4) and (+)-JQ1-derived chemical probes have played a vital role in chemical biology and drug discovery over the past decade, which is demonstrated by the high number of impactful research studies published since the disclosure of (+)-JQ1 (4) in 2010. In this review, we discuss the development of (+)-JQ1-derivatized chemical probes over the past decade and their significant contribution to scientific research. Specifically, we will summarize the development of innovative label-free and labeled (+)-JQ1-derivatized chemical probes, such as bivalent, covalent, and photoaffinity probes as well as protein degraders, with a focus on the design of these chemical probes.

Binding-Site Purification of Actives (B-SPA) Enables Efficient Large-Scale Progression of Fragment Hits by Combining Multi-Step Array Synthesis With HT Crystallography

Fragment approaches are long-established in target-based ligand discovery, yet their full transformative potential lies dormant because progressing the initial weakly binding hits to potency remains a formidable challenge. The only credible progression paradigm involves multiple cycles of costly conventional design-make-test-analyse medicinal chemistry. We propose an alternative approach to fragment elaboration, namely performing large numbers of parallel and diverse automated multiple step reactions, and evaluating the binding of the crude reaction products by high-throughput protein X-ray crystallography. We show it is effective and low-cost to perform, in parallel, large numbers of non-uniform multi-step reactions, because, even without compound purification, crystallography provides a high-quality readout of binding. This can detect low-level binding of weakly active compounds, which the target binding site extracts directly from crude reaction mixtures. In this proof-of-concept study, we have expanded a fragment hit, from a crystal-based screen of the second bromodomain of pleckstrin homology domain-interacting protein (PHIP(2)), using array synthesis on low-cost robotics. We were able to implement 6 independent multi-step reaction routes of up to 5 steps, attempting the synthesis of 1876 diverse expansions, designs entirely driven by synthetic tractability. The expected product was present in 1108 (59%) crude reaction mixtures, detected by liquid chromatography mass spectrometry (LCMS). 22 individual products were resolved in the crystal structures of crude reaction mixtures added to crystals, providing an initial structure activity relationship map. 19 of these showed binding pose stability, while, through binding instability in the remaining 3 products, we could resolve a stereochemical preference for mixtures containing racemic compounds. One compound showed biochemical potency (IC50=34 μM) and affinity (Kd=50 μM) after resynthesis. This approach therefore lends itself to routine fragment progression, if coupled with algorithmically guided compound and reaction design and new formalisms for data analysis.

Naphthalene diimide-naphthalimide dyads promote telomere damage by selectively targeting multimeric G-quadruplexes

G-quadruplex (G4) nucleic acid ligands have attracted significant attention as putative anticancer agents for selectively stabilizing telomeric structures. In our pursuit of targeting the most biologically relevant telomeric structures, we have investigated a new class of naphthalene diimide (NDI)-based ligands designed to bind multimeric G4s. The NDI unit covalently linked with one 1,8-naphthalimide (NI) moiety, results in ligands able to fold into a sandwich-like conformation fitting into the binding pockets of telomeric multimeric G4s, thus optimizing binding complementarity. Varying the NDI decorations, we synthesized a small library of NDI-NI dyads and then examined their capability of stabilizing G4s by biophysical assays. Given the relevance of G4 stabilizing agents in fighting cancer, the most promising NDI-NIs were evaluated for their antitumoral activity on a panel of human cell lines originating from different tumor histotypes. Obtained results evidenced that three of the selected ligands promoted an accumulation of telomere-localized damage leading to a robust impairment of cell viability, regardless of homologous recombination status. These data, then confirmed in advanced 3D models, paved the way for the advancement of NDI-NIs as a new class of clinically relevant antitumoral agents. Finally, computational analyses gained deeper insight into their binding modality.

Identification of an Allene Warhead That Selectively Targets a Histidine Residue in the Escherichia coli Oxidoreductase Enzyme DsbA

Small molecules that covalently modify proteins typically contain an electrophile that selectively reacts with nucleophilic residues in a protein target, such as cysteine, serine, and threonine. Targeting other amino acids is an emerging strategy in covalent probe design. This study reports the discovery and characterization of the covalent reaction between a novel allene warhead and a histidine residue in the active site of the bacterial thiol-disulfide oxidoreductase enzyme Escherichia coli DsbA (EcDsbA). Allenes have not been widely reported for their use as covalent warheads. The interaction was characterized by X-ray crystallography, nuclear magnetic resonance spectroscopy, and mass spectrometry. This analysis provided insights into the structure, reaction rate, and selectivity of the allene. Investigation of the reactivity with nucleophilic amino acids revealed that the reaction with the allene warhead shows some specificity for the histidine in the active site of EcDsbA. Thus, the allene represents a novel histidine-modifying warhead.

Design, Synthesis, and Evaluation of Boron Dipyrromethene-Based Fluorescent Probes Targeting BRAF for Melanoma Diagnosis

Fluorescent dyes are widely applied in clinical diagnosis, detection, and treatment of diseases. Several image probes such as ICG, MB, and 5-ALA have been approved by FDA. However, the limited tumor-targeting capability of these dyes hinders their effectiveness in oncological imaging. Currently, various ligand-based targeting probes have been developed to minimize nonspecific background emission. BRAF, especially BRAF V600E, is a common cancer gene and undergoes frequent mutation in melanoma. Small molecular BRAF kinase inhibitors have been approved for the treatment of melanoma patients carrying the BRAF V600E mutation, including Vemurafenib, Dabrafenib and so on. Boron dipyrromethene (BODIPY) as an important fluorescent class has been investigated extensively. Vemurafenib-BODIPY has been reported to visualize BRAF V600E mutated cancer cells. Herein, the designed BODIPY-based Vemurafenib derivatives targeting BRAF for cancer cell imaging are reported. The fluorescent probes are characterized and evaluated of photophysical properties, targeted binding and live cell imaging. Compound 1a exhibited promising fluorescence imaging ability. To improve fluorescence quantum yield, structural optimization is performed by incorporating meso N,N'-dialkyl-substituted amides to BODIPY core. Compound 1d shows excellent fluorescence properties and nice binding affinity. It allows visualization of BRAF V600E mutated cancer cells at low concentrations.

From Natural Products to Small Molecules: Recent Advancements in Anti-MRSA Therapeutics

The urgent need for unique small molecules to treat increasing resistance in gram-positive pathogens, particularly methicillin-resistant Staphylococcus aureus, has motivated several creative research endeavors over the past decade. Recent advances have been inspired by natural products such as pleuromutilin, discovered in high-throughput screens, or repurposed approved drugs like sorafenib. This microperspective spotlights bioactive compounds, ranging from natural products to small molecule scaffolds, that have been reported in recent literature, highlighting their mechanisms of action, structure-activity relationships, and future potential.

Allosteric modulation by the fatty acid site in the glycosylated SARS-CoV-2 spike

The spike protein is essential to the SARS-CoV-2 virus life cycle, facilitating virus entry and mediating viral-host membrane fusion. The spike contains a fatty acid (FA) binding site between every two neighbouring receptor-binding domains. This site is coupled to key regions in the protein, but the impact of glycans on these allosteric effects has not been investigated. Using dynamical nonequilibrium molecular dynamics (D-NEMD) simulations, we explore the allosteric effects of the FA site in the fully glycosylated spike of the SARS-CoV-2 ancestral variant. Our results identify the allosteric networks connecting the FA site to functionally important regions in the protein, including the receptor-binding motif, an antigenic supersite in the N-terminal domain, the fusion peptide region, and another allosteric site known to bind heme and biliverdin. The networks identified here highlight the complexity of the allosteric modulation in this protein and reveal a striking and unexpected link between different allosteric sites. Comparison of the FA site connections from D-NEMD in the glycosylated and non-glycosylated spike revealed that glycans do not qualitatively change the internal allosteric pathways but can facilitate the transmission of the structural changes within and between subunits.

Design, Synthesis, and Evaluation of a New Fluorescent Ligand for the M2 Muscarinic Acetylcholine Receptor

The M2 muscarinic acetylcholine receptor (M2R) is a G protein-coupled receptor involved in regulating cardiovascular functions and mediation of central muscarinic effects, such as movement, temperature control, and antinociceptive responses. Molecular probes targeting this receptor are therefore important in exploring its pathophysiological role at a molecular level. Herein, we report the design, synthesis, and evaluation of a new fluorescent probe for M2R based on an anthranilamide ligand. In radioligand binding experiments, the presented Oregon Green 488-labeled conjugate (33) exhibited high M2R affinity (K i = 2.4 nM), a moderate preference for the M2R over the M4 receptor, and excellent to pronounced M2R selectivity compared to the M1, M3, and M5 receptors. The utility of the probe was demonstrated in confocal, two-photon, and stimulated emission depletion nanoscopy (STED) imaging to specifically label the receptors in human embryonic kidney (HEK) 293T cells. These properties suggest that our probe may be utilized in advanced microscopy to study the pharmacology of the M2R.

N-Terminal Stabilization of Radiolabeled Neurotensin Analogues for Improved Tumor Uptake

Peptide-based radiopharmaceuticals targeting neurotensin-receptor-1 (NTS1) are mainly stabilized using chemical modifications at the NT[8-13] sequence, thus increasing the stability and the uptake of the corresponding radionuclide-macrocycle-linker-bioconjugate. We postulate that the introduction of the linker at the N-term part induces additional cleavage sites that can be further stabilized to achieve a prolonged uptake. Double (JMV 7259 and JMV 7222) and triple-stabilized neurotensin analogues (JMV 7258 and JMV 7490) were synthesized, radiolabeled, and evaluated on HT-29 cells (NTS1+). Nanomolar NTS1-affinity and high internalization rates were observed for all of the radiopharmaceuticals. Efflux was lower for radiolabeled JMV 7490. Consequently, [111In]In-JMV 7490 showed uptake of 5.86 ± 0.86 and 3.65 ± 0.29% ID/g of tissue in HT-29 xenografts at 1 and 4 h, respectively. We have successfully shown that high and persistent uptake of NTS1-positive tumor cells is achievable by stabilization of the N-term part. Efflux also appears to be a critical parameter for the successful targeting of NTS1 using radiopharmaceuticals.

Global research trends in inflammaging from 2005 to 2024: a bibliometric analysis

Background

Inflammaging, defined as chronic low-grade inflammation associated with aging, is considered a key factor in many age-related diseases. Despite growing research, comprehensive assessments of trends and focuses on this field over the past 2 decades remain lacking.

Objective

To comprehensively analyze literature development trends, scientific priorities, and their evolution in the field of inflammaging from 2005 to 2024 using bibliometric analysis.

Methods

Academic literature on inflammaging was retrieved from the Web of Science Core Collection. CiteSpace software was used as the bibliometric tool to analyze annual publication trends, contributing countries/regions, leading research institutions, primary journals, and keyword co-occurrence, including clustering and burst analysis in this field.

Results

The study included 1,800 eligible articles, demonstrating a consistent growth in research publications over the past 20 years. The United States and Italy were the principal contributors. The University of Bologna had the highest publication. Professor Claudio Franceschi has been a leading figure in this field. Journal analysis shows that research themes predominantly focus on molecular biology/immunology and medicine/clinical fields. Keyword analysis identifies major research hotspots as "inflammaging," "Crohn's disease," "periodontitis," "immunosenescence," "skeletal muscle," "gut microbiota," and "Parkinson's disease." Emerging term analysis indicates a shift from specific inflammatory diseases to broader aging and immune modulation studies.

Conclusion

This first systematic assessment of literature trends in the field of inflammaging from 2005 to 2024 reveals sustained academic growth and an increasingly deep research focus.

Development of a Cyclic TMTP1-Based PET Probe for Visualization of Hepatocellular Carcinoma

TMTP1 is a tumor-homing peptide that selectively targets highly metastatic tumor cells with XPNPEP2 identified as its potential targeting receptor. Although TMTP1-based molecular probes have been explored for imaging tumors such as hepatocellular carcinoma (HCC), their clinical translation has been hampered by factors including suboptimal tumor uptake and rapid systemic clearance. To study possible solution for addressing these challenges, a cyclic TMTP1 based positron emission tomography (PET) probe, [68Ga]Ga-DOTA-cTMTP1, was designed, synthesized, and evaluated for imaging HCC in small animal models. [68Ga]Ga-DOTA-cTMTP1 demonstrated favorable aqueous solubility, with a log D 7.4 value of -3.28 ± 0.05, and it exhibited excellent in vitro stability in phosphate buffered saline (PBS) and fetal bovine serum (FBS). Biodistribution studies revealed a certain level of tumor accumulation (0.98 ± 0.14%ID/g at 30 min) and retention (0.40 ± 0.11%ID/g at 120 min). Impressively, [68Ga]Ga-DOTA-cTMTP1 maintained high tumor-to-liver contrast over time, with ratios of 2.65 ± 0.45 at 30 min, 2.37 ± 0.07 at 60 min, and 2.14 ± 0.20 at 120 min. It also displayed capability of clear visualization of small HCC foci (<4 mm) in transgenic c-Myc liver tumor mice models, with tumor/liver ratios 2.20 ± 0.10 at 30 min, 2.26 ± 0.11 at 60 min, and 2.55 ± 0.44 at 120 min, respectively. Overall, this study highlights that [68Ga]Ga-DOTA-cTMTP1 has favorable pharmacokinetic and in vivo tumor imaging profile, and it is a highly promising probe for visualization of HCC microlesions. Development of PET probes based on cyclic TMTP1 is a promising approach for discovering novel imaging probes.

Computational Investigation of Montelukast and Its Structural Derivatives for Binding Affinity to Dopaminergic and Serotonergic Receptors: Insights from a Comprehensive Molecular Simulation

Background/Objectives: Montelukast (MLK), a leukotriene receptor antagonist, has been associated with neuropsychiatric side effects. This study aimed to rationally modify MLK's structure to reduce these risks by optimizing its interactions with dopamine D2 (DRD2) and serotonin 5-HT1A receptors using computational molecular simulation techniques. Methods: A library of MLK derivatives was designed and screened using structural similarity analysis, molecular docking, molecular dynamics (MD) simulations, MM/PBSA binding free energy calculations, and ADME-Tox predictions. Structural similarity analysis, based on Tanimoto coefficient fingerprinting, compared MLK derivatives to known neuropsychiatric drugs. Docking was performed to assess initial receptor binding, followed by 100 ns MD simulations to evaluate binding stability. MM/PBSA calculations quantified binding affinities, while ADME-Tox profiling predicted pharmacokinetic and toxicity risks. Results: Several MLK derivatives showed enhanced DRD2 and 5-HT1A binding. MLK_MOD-42 and MLK_MOD-43 emerged as the most promising candidates, exhibiting MM/PBSA binding free energies of -31.92 ± 2.54 kcal/mol and -27.37 ± 2.22 kcal/mol for DRD2 and -30.22 ± 2.29 kcal/mol and -28.19 ± 2.14 kcal/mol for 5-HT1A, respectively. Structural similarity analysis confirmed that these derivatives share key pharmacophoric features with atypical antipsychotics and anxiolytics. However, off-target interactions were not assessed, which may influence their overall safety profile. ADME-Tox analysis predicted improved oral bioavailability and lower neurotoxicity risks. Conclusions: MLK_MOD-42 and MLK_MOD-43 exhibit optimized receptor interactions and enhanced pharmacokinetics, suggesting potential neuropsychiatric applications. However, their safety and efficacy remain to be validated through in vitro and in vivo studies. Until such validation is performed, these derivatives should be considered as promising candidates with optimized receptor binding rather than confirmed safer alternatives.

Discovery of a Series of Covalent Ligands That Bind to Cys77 of the Von Hippel-Lindau Tumor Suppressor Protein (VHL)

Most ligands for the Von Hippel-Lindau tumor suppressor (VHL) bind at the HIF-1α binding site. Ligands that bind to allosteric sites on VHL could be highly valuable for the field of protein degradation, therefore, a covalent hit identification campaign was run targeting Cys77 on VHL. Hit 2 bound selectively to Cys77 on VHL and did not alkylate the reactive Cys89 on Elongin B. It showed time- and concentration-dependent labeling, with a k inact/K I of 0.30 M-1 s-1, and does not affect binding at the HIF-1α site. This hit ligand was optimized to afford compound 15 which showed improved potency and labeling of VHL. An X-ray structure of a close analogue was determined revealing the compound binding in a shallow groove on the surface of VHL. These are the first small molecules that bind covalently to an allosteric site on VHL and provide a suitable starting point for further optimization.

Discovery of Highly Potent AKR1C3 Inhibitors Treating Sorafenib-Resistant Hepatocellular Carcinoma

Aldo-keto reductase 1C3 (AKR1C3) plays a key role in tumor progression and chemotherapy resistance, particularly in sorafenib-resistant hepatocellular carcinoma (HCC). Targeting AKR1C3 represents a promising strategy to restore chemosensitivity in resistant HCC. Previous research identified the lead compound S07-2005 through a cascade virtual screening approach (AKR1C3 IC50 = 130 ± 30 nM, SI (selective index) > 77). Using cocrystal-guided drug design, 30 was optimized to adopt an "L"-shaped conformation targeting AKR1C3's subpocket 1 (SP1) and oxyanion site (OS), enhancing inhibitory potency and selectivity (AKR1C3 IC50 = 5 ± 1 nM, SI > 2000). It enhanced sorafenib-induced ROS generation, promoted apoptosis, and restored sorafenib sensitivity in HCC models. In combination with sorafenib, compound 30 restored sorafenib sensitivity in HCC both in vitro and in vivo. Additionally, compound 30 demonstrated a favorable safety profile and pharmacokinetic properties, suggesting its potential as an adjunct to overcome AKR1C3-mediated chemotherapy resistance in cancer treatment.

Deubiquitinase-Targeting Chimeras (DUBTACs) as a Potential Paradigm-Shifting Drug Discovery Approach

Developing proteolysis-targeting chimeras (PROTACs) is well recognized through target protein degradation (TPD) toward promising therapeutics. While a variety of diseases are driven by aberrant ubiquitination and degradation of critical proteins with protective functions, target protein stabilization (TPS) rather than TPD is emerging as a unique therapeutic modality. Deubiquitinase-targeting chimeras (DUBTACs), a class of heterobifunctional protein stabilizers consisting of deubiquitinase (DUB) and protein-of-interest (POI) targeting ligands conjugated with a linker, can rescue such proteins from aberrant elimination. DUBTACs stabilize the levels of POIs in a DUB-dependent manner, removing ubiquitin from polyubiquitylated and degraded proteins. DUBTACs can induce a new interaction between POI and DUB by forming a POI-DUBTAC-DUB ternary complex. Herein, therapeutic benefits of TPS approaches for human diseases are introduced, and recent advances in developing DUBTACs are summarized. Relevant challenges, opportunities, and future perspectives are also discussed.

Adamantane-Quinoxalone Hybrids: Precision Chemotypes and Their Molecular Mechanisms in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is an aggressive blood cancer with a poor prognosis, especially when diagnosed late. Around 10-15% of cases involve the specific chromosomal abnormality t(8;21), which drives uncontrolled myeloid cell proliferation and contributes to disease onset. Despite advances in AML research and treatment protocols, outcomes for t(8;21) AML remain stagnant, as patients receive standard, nonspecific chemotherapies. This one-size-fits-all approach targets both cancerous and healthy cells, leading to unwanted toxicity and highlighting the urgent need for targeted therapies. In this study, we present a precision chemotype based on a quinoxalone-tethered adamantane framework developed via a metal- and light-free protocol. The compound selectively inhibits t(8;21) AML cell proliferation and induces cell death by disrupting growth and metabolic pathways, as demonstrated through bioassays, RNA sequencing, and proteomic analysis. Notably, it spares other leukemic and solid cancer cells, underscoring its specificity and potential as a targeted therapy for t(8;21) AML.

4-Exo-Trig Radical Cyclization: A Promising Approach to Four-Membered Rings

The 4-exo-trig radical cyclization represents a formidable challenge owing to the unfavorable thermodynamics associated with the formation of highly strained four-membered rings. Stimulated by the explosive advancements of radical chemistry over the past decades, significant progresses have been made in this area, including the SmI2-mediated 4-exo-trig carbonyl-alkene cyclization, n-Bu3SnH-mediated 4-exo cyclization of functionalized alkenes or alkynes, transition metal-catalyzed 4-exo-trig ring closures, and visible light-induced 4-exo-trig cyclization cascade, providing efficient protocols to overcome the inherent limitations and expand the synthetic utility of this methodology. Representative examples, reaction mechanism, scope and limitations, and synthetic applications are presented and discussed in detail. We believe that the systematic review of recent advances on 4-exo-trig radical cyclization will provide more insights in this field, and may enable further development of this cyclization process for the concise synthesis of four-membered carbo- and heterocycles that are difficult to access via traditional methods.

Antimicrobial p-terphenyl derivatives from the deep-sea cold seep-derived fungus Aspergillus candidus

Four new p-terphenyl derivatives named phenylcandilides C-F, together with nine known analogues, were isolated from the deep-sea cold-seep-derived fungus Aspergillus candidus HNNU0546. Compounds 10 and 12 exhibited antibacterial activity against Staphylococcus aureus with MIC values of 21.6 and 23.6 µM, respectively. Compound 5 showed antifungal activity with an EC50 value of 3.0 µM against phytopathogenic fungus Alternaria sp., while compound 6 exhibited inhibitory activity against Curvularia australiensis and Alternaria sp. with the same EC50 values of 3.0 µM, respectively.

A mechanoresponsive heterochiral hydrogelator as a potential matrix metalloproteinase-2 inhibitor: unravelling its anti-inflammatory efficacy in vitro and in vivo

Inflammations are innate and adaptive immune responses that get instigated in reciprocation to infection. However, if left unchecked, they pose a formidable challenge in clinical settings. In search of user-friendly solutions, our work delineated a rational combinatorial strategy, harnessing chiral orchestration in a triphenylalanine fragment and appending it to δ-amino valeric acid at the N-terminus (hydrogelators I-VIII) such that a potential matrix metalloproteinase-2 (MMP2) inhibitor could be fished out from the design. Our rigorous investigations revealed that from a pool of eight constructs, hydrogelator VIII, with a DLL configuration at the triphenylalanines, displayed excellent MMP2 inhibitory activities in vitro, which was further supported by molecular modelling studies. Besides, the β-sheet structured scaffold not only showed substantial antibacterial efficacy against the Gram-positive pathogens S. aureus, S. mutans, B. subtilis and E. fecalis but also exhibited proteolytic stability and biocompatibility towards mammalian cells. Furthermore, the scaffold possessed high mechanical strength at physiological pH and mechanical stress-triggered gel-sol-gel transition properties. Finally, the in vivo efficacy was evaluated using an air pouch model of acute inflammation in albino mice that certified hydrogelator VIII as a promising anti-inflammatory therapeutic to pave the path for future healthcare management.

MAST Kinases' Function and Regulation: Insights from Structural Modeling and Disease Mutations

Background/Objectives: The MAST kinases are ancient AGC kinases associated with many human diseases, such as cancer, diabetes, and neurodevelopmental disorders. We set out to describe the origins and diversification of MAST kinases from a structural and bioinformatic perspective to inform future research directions. Methods: We investigated MAST-lineage kinases using database and sequence analysis. We also estimate the functional consequences of disease point mutations on protein stability by integrating predictive algorithms and AlphaFold. Results: Higher-order organisms often have multiple MASTs and a single MASTL kinase. MAST proteins conserve an AGC kinase domain, a domain of unknown function 1908 (DUF), and a PDZ binding domain. D. discoideum contains MAST kinase-like proteins that exhibit a characteristic insertion within the T-loop but do not conserve DUF or PDZ domains. While the DUF domain is conserved in plants, the PDZ domain is not. The four mammalian MASTs demonstrate tissue expression heterogeneity by mRNA and protein. MAST1-4 are likely regulated by 14-3-3 proteins based on interactome data and in silico predictions. Comparative ΔΔG estimation identified that MAST1-L232P and G522E mutations are likely destabilizing. Conclusions: We conclude that MAST and MASTL kinases diverged from the primordial MAST, which likely operated in both biological niches. The number of MAST paralogs then expanded to the heterogeneous subfamily seen in mammals that are all likely regulated by 14-3-3 protein interaction. The reported pathogenic mutations in MASTs primarily represent alterations to post-translational modification topology in the DUF and kinase domains. Our report outlines a computational basis for future work in MAST kinase regulation and drug discovery.

The outcast of medicine: metals in medicine--from traditional mineral medicine to metallodrugs

Metals have long held a significant role in the human body and have been utilized as mineral medicines for thousands of years. The modern advancement of metals in pharmacology, particularly as metallodrugs, has become crucial in disease treatment. As the machanism of metallodurgsare increasingly uncovered, some metallodrugs are already approved by FDA and widely used in treating antitumor, antidiabetes, and antibacterial. Therefore, a thorough understanding of metallodrug development is essential for advancing future study. This review offers an in-depth examination of the evolution of mineral medicines and the applications of metallodrugs within contemporary medicine. We specifically aim to summarize the historical trajectory of metals and mineral medicines in Traditional Chinese Mineral Medicine by analyzing key historical texts and representative mineral medicines. Additionally, we discuss recent advancements in understanding metallodrugs' mechanisms, such as protein interactions, enzyme inhibition, DNA interactions, reactive oxygen species (ROS) generation, and cellular structure targeting. Furthermore, we address the challenges in metallodrug development and propose potential solutions. Lastly, we outline future directions for metallodrugs to enhance their efficacy and effectiveness. The progression of metallodrugs has broadened their applications and contributed significantly to patient health, creating good healthcare solutions for the global population.

Head-to-Head Comparison of the in Vivo Performance of Highly Reactive and Polar 18F-Labeled Tetrazines

Pretargeted imaging harnessing tetrazine ligation has gained increased interest over recent years. Targeting vectors with slow pharmacokinetics may be visualized using short-lived radionuclides, such as fluorine-18 (18F) for positron emission tomography (PET), and result in improved target-to-background ratios compared to conventionally radiolabeled slowly accumulating vectors. We recently developed different radiochemical protocols enabling the direct radiofluorination of various tetrazine scaffolds, resulting in the development of various highly reactive and polar 18F-labeled tetrazines as lead candidates for pretargeted imaging. Here, we performed a direct head-to-head-comparison of our lead candidates to evaluate the most promising for future clinical translation. For that, all 18F-labeled tetrazine-scaffolds were synthesized in similar molar activity for improved comparability of their in vivo pretargeting performance. Intriguingly, previously reported dicarboxylic acid lead candidates with a net charge of -1 were outperformed by respective monocarboxylic acid derivatives bearing a net charge of 0, warranting further evaluation of such scaffolds prior to their clinical translation.