An updated review on the role of small molecules in mediating protein degradation

Targeted protein degradation (TPD) technologies, inspired by physiological processes, have recently provided new directions for drug development. Unlike conventional drug development focusing on targeting the active sites of disease-related proteins, TPD can utilize any nook or cranny of a protein to drive degradation through the cell's inherent destruction mechanism. It offers various advantages such as stronger pharmacological effects, an expanded range of drug targets, and higher selectivity. Based on the ubiquitin-proteasome system and the lysosomal degradation pathway, a variety of TPD strategies have been developed including PROTAC, PROTAB, and AUTOTAC. These TPD strategies have continuously enriched the toolbox for targeted protein degradation and expanded the scope of application, providing new ideas for biological research and drug discovery. This review attempts to introduce up-to-date research progress in the TPD strategies, focusing mainly on their design concepts, advantages, potential applications, and challenges, which may provide some inspiration for drug design, drug discovery, and clinical application for biologists and chemists.

Synthesis and evaluation of piceatannol derivatives as novel arginase inhibitors with radical scavenging activity and their potential for collagen reduction in dermal fibroblasts

High arginase activity is associated with several pathological conditions, including TGF-β-induced fibrosis, by increasing levels of the proline precursor l-ornithine, thereby promoting collagen biosynthesis and increasing oxidative stress due to nitric oxide synthase (NOS) uncoupling. The natural piceatannol has been shown to have beneficial effects on collagen deposition, fibrosis and oxidative stress. In this study, we present an in-depth structure-activity relationship study on arginase I, which resulted in the thioamide derivative 12a with dual catechol rings that displays potent inhibitory activity with IC₅₀ values of 9 μM and 55 μM for bovine and human arginase I, respectively. Quantum chemical modelling suggested that the sulphur atom in the thioamide group plays a crucial role in binding affinity by forming a stable hydrogen bond within the active site of the enzyme. In addition, compound 12a demonstrated high radical scavenging activity and effectively normalised collagen and procollagen levels at 5 μM in an in vitro cell model of a dermal fibrosis.

Structure-Activity Study of the Antimicrobial Lipopeptide Humimycin A and Screening Against Multidrug-Resistant Staphylococcus aureus

BACKGROUND

The emergence of multidrug-resistant (MDR) Staphylococcus aureus presents a critical global health challenge due to treatment failures and high mortality rates. Faced with this growing threat, new antimicrobials with original modes of action are urgently needed, and antimicrobial peptides proved to be promising alternatives.

OBJECTIVES

The aim of this study is to explore the structure-function relationship of the lipopeptide humimycin A, compare the spectrum of activity of the synthetic analogs against a panel of S. aureus isolates, and investigate their binding to the humimycin target, the lipid II flippase MurJ.

METHODS

Humimycin A and 15 analogs were produced by solid-phase peptide synthesis, and their antimicrobial activity was evaluated by agar diffusion and microtitration assays against 19 S. aureus isolates from bovine mastitis and other pathogens.

RESULTS

Among the synthesized peptides, four humimycin analogs exhibited activity against methicillin-sensitive and methicillin-resistant S. aureus, as well as several isolates in the panel, including MDR S. aureus, with minimal inhibitory concentration values ranging from 0.5 to 256 µg/mL. Results from the structure-activity relationship study showed that the β-hydroxymyristoyl lipid chain and C-terminal carboxylic acid are essential for antimicrobial efficacy. In presence of human erythrocytes, the active humimycin analogs exhibited moderate hemolytic activity, suggesting selectivity indexes ranging from 3 to 27 against the more sensitive S. aureus strains. Critical micelle concentration measurements elucidated micelle formation and proved to not be essential for the antibacterial activity. Molecular docking and 100 ns simulations with the lipid II flippase MurJ (PDB: 5T77) provided favorable binding energy.

CONCLUSIONS

The findings underscore the potential of humimycin analogs as antimicrobials for preventing and treating MDR S. aureus infections in veterinary, animal husbandry, and human medicine.

Natural sideromycins and siderophore-conjugated natural products as inspiration for novel antimicrobial agents

The widespread emergence of multidrug-resistant (MDR) Gram-negative pathogens has posed a major challenge to clinical anti-infective therapy, and new effective treatments are urgently needed. A promising "Trojan horse" strategy involves conjugating antibiotics to siderophore molecules; the resulting siderophore-antibiotic conjugates (SACs) deliver antibiotics directly into cells by hijacking the sophisticated iron transport systems of Gram-negative bacteria, bypassing the outer membrane permeability barrier to enhance uptake and antibacterial efficacy. The clinical release of the first siderophore-antibiotic conjugate, cefiderocol, has aroused tremendous interest in the field among researchers and pharmaceutical companies. To date, most of the reported SACs have focused on the conjugation of siderophores to traditional antibacterial drugs. However, these antibacterial agents designed on the basis of the traditional antibiotic skeleton theoretically bear the risk of cross-resistance caused by shared molecular scaffolds. In this case, exploring novel natural product antibacterial conjugate scaffolds to circumvent the risk of early cross-resistance represents a presumably more sustainable approach for the development of SACs. In this review, we systematically summarize the research progress on siderophore-natural product conjugates as novel antimicrobial agents reported since 2010. Additionally, we propose challenges to be overcome and prospects for future development in this field.

In vitro and in vivo evaluation of anti-HER2 antibody conjugates labelled with 225Ac

BACKGROUND

Overexpression of human epidermal growth factor receptor type 2 (HER2) occurs in multiple carcinomas. For example, up to 20% of breast cancer cases are classified as HER2 positive (HER2+). Treatment of this condition typically involves immunotherapy using monoclonal antibodies, such as trastuzumab or pertuzumab. The precise targeting of monoclonal antibodies to HER2+ tumour lesions can be used as well in radioimmunotherapy to deliver medical radionuclides exactly to the afflicted area and therefore minimize radiation exposure of healthy tissues. In this study, DOTA conjugates of monoclonal antibodies trastuzumab and pertuzumab were prepared and tested in vitro. One of these, 225Ac-DOTA-pertuzumab, was also the subject of an ex vivo biodistribution study with normal as well as HER2+ and HER2- tumour-xenografted mice. This radioconjugate has not been previously described.

RESULTS

Three DOTA-conjugates of HER2 targeting monoclonal antibodies, one of trastuzumab and two of pertuzumab, were prepared and radiolabelled with 225Ac in different molar ratios. This procedure led to an optimisation of the preparation and radiolabelling process. The radioconjugates were shown to be highly stable in vitro in both fetal bovine serum and phosphate buffered saline under room temperature and decreased temperature for 10 days. In vitro cell studies with HER2-overexpressing cell-line (SKOV-3) and low HER2-expressing cell line (MDA-MB-231) proved that radioconjugates of both antibodies have high binding specificity and affinity towards HER2 receptors. These findings were confirmed for a novel radioconjugate 225Ac-DOTA-pertuzumab in an ex vivo biodistribution study, where uptake in HER2+ tumour was 50 ± 14% ID/g and HER2- tumour showed uptake comparable with healthy tissues (max. 5.0 ± 1.7% ID/g). The high uptake observed in the spleen can be attributed to the elimination of the antibody, as well as the use of an immunedeficient mouse strain (SCID).

CONCLUSIONS

During this study, the optimization of preparation and radiolabelling of HER2 targeting antibodies with 225Ac was accomplished. Furthermore, the radioconjugate 225Ac-DOTA-pertuzumab was prepared and evaluated for the first time. The radioconjugates of both tested antibodies demonstrated excellent qualities in terms of stability and HER2 receptor affinity. Initial ex vivo studies indicated that especially the radioconjugate 225Ac-DOTA-pertuzumab is a very promising candidate for further more detailed in vivo studies.

Argatroban and Menadione exert protective effects in ultraviolet-irradiated skin inflammation: A transcriptomic analysis based on identification of iron overload related biomarkers

Ultraviolet light (UV) can cause serious damage to human skin. The inflammatory reaction arising from repeated UV exposure leads to severe skin lesions and even promotes photo-carcinogenesis. Iron overload is featured by excessive iron intake and deposition and will promote inflammatory response inside cells. However, the core molecules involved in UV radiation induced iron overload and related anti-inflammatory strategies remain unclear. Signature genes involved in UV-irradiated skin were filtered through integrated datasets from the Gene Expression Omnibus (GEO) database. Subsequently, immune cell infiltration analysis was carried out to examine the relationship between signature gene expression and immune cell abundance. Single cell RNA-seq matrix data implicated in UV-irradiated skin was then applied to assess the expression level of signature genes in different cell clusters and to find out the core cell type and the key signaling pathway involved in UV radiation. Finally, cytological and animal experiments were conducted to investigate the potential of signature genes as therapeutic targets. SAT1 and RBMS1 were screened and validated as signature genes of UV irradiation. Immune cell infiltration analysis demonstrated that SAT1 and RBMS1 expression were associated closely with immune cell abundance, and skin fibroblasts were identified as the central cell type to communicate with other cell clusters in UV-irradiated skin. Disturbance of SAT1 exerted observably more suppressive effects on the release of inflammatory cytokines than overexpression of RBMS1. Two small molecule drugs targeting SAT1, namely Argatroban and Menadione, were predicted. Moreover, their therapeutic potentials in the treatment of UV-irradiated skin injury were confirmed experimentally.

Cinchona alkaloid copolymers as fluorimetric INHIBIT and colorimetric AND logic gates for detection of iodide

Four cinchona alkaloid-acrylamide water soluble copolymers with a mean hydrodynamic diameter of 3 nm were synthesised by free radical polymerization. The copolymers were characterised by 1H NMR, FTIR, GPC, DLS, UV-vis and fluorescence spectroscopy. A blue emission is observed with H+ switching of 185 and 175-fold for the quinidine and quinine copolymers, and 21 and 11-fold for the cinchonine and cinchonidine copolymers, while the presence of Cl-, Br- or I- causes fluorescence quenching. In emission mode, the copolymers function as fluorescent H+, X--driven INHIBIT logic gates (where X = Cl-, Br- or I-). In absorbance mode, the copolymers function as colorimetric H+, I--driven AND logic gates in 1 : 1 (v/v) THF/water with a 76-fold enhancement. The solution colour changes from colourless to yellow with formation of new absorbance bands at 288 nm and 353 nm due to a π-anion non-covalent charge transfer interaction. The copolymers may be useful as selective iodide sensors for medical and analytical diagnostics.

A scaffold repositioning approach: dihydroBenzoImidazoTriazineDione (BITD) derivatives as selective ALDH1A1 inhibitors

The overexpression of the Aldehyde Dehydrogenases 1A subfamily (ALDH1As) in various diseases, particularly in cancer, has made it an important target for therapeutic applications. Interestingly, the 1A1 isoenzyme plays a role in tumor initiation and progression, being identified as a biomarker for cancer stem cells. However, although promising, current ALDH1A1 inhibitors suffer from a lack of isoform selectivity and off-target toxicity. This study aims to address these limitations by developing a new class of ALDH1A1-selective inhibitors. By leveraging structural analogies with Isatin-based ALDH1A1 inhibitors, we designed compounds containing a dihydrobenzo[4,5]imidazo[2,1-c][1,2,4]triazine-3,4-dione (BITD) core, that emerged from a repositioning approach. Using a microwave-assisted protocol, a small library of derivatives was synthesized, and enzymatic assays highlighted a promising isoform specificity for ALDH1A1 among ALDH1As, with the best-in-class compound 5, showing an inhibition of the enzyme activity of 86% for ALDH1A1 and no inhibition for 1A2 and 1A3 isoenzymes. In silico studies further elucidated the binding mode of 5, providing a rational basis for the observed selectivity. These findings represent a promising strategy for the development of more selective ALDH1A1 inhibitors, laying the foundation for further optimization processes.

Photoredox/Copper Cooperatively Catalyzed Arylalkynylation of [1.1.1]Propellane

We present a sp2-sp3/sp3-sp bond formation reaction through a three-component coupling strategy involving terminal alkynes, [1.1.1]propellane, and aryl thianthrenium salts that are prepared from arenes. The reaction employs a dual photo/copper catalysis system and provides a streamlined approach for assembling 1-alkynyl-3-aryl bicyclo[1.1.1]pentane derivatives with a broad spectrum of functional group compatibility. Mechanistic studies suggest that the generation of aryl radicals and copper alkynide intermediates was involved.

Uvarinol and Dichamanetin Derived from Uvaria chamae as Potential Dual-Site Inhibitors Against PBP2a in Methicillin Resistant Staphylococcus aureus: An In Silico Study

Background/Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the resistant pathogenic microorganisms that poses a global health threat due to its resistance to β-lactam antibiotics where the protein penicillin-binding protein 2a (PBP2a) plays a crucial role in its resistance. This study explores the potential of phytochemicals from Uvaria chamae, a plant with known medicinal properties, to serve as dual-site inhibitors of PBP2a, targeting both the active and allosteric sites. Methods: Phytochemicals previously identified in U. chamae were subjected to molecular docking and molecular dynamics simulations to evaluate their binding affinities and stability at PBP2a's active and allosteric sites. The compounds' pharmacokinetic profiles were predicted in silico using SwissADME tools. Root-mean-square deviation (RMSD), radius of gyration, and binding free energy were analyzed for dynamic stability. Results: Among the evaluated compounds, Uvarinol and Dichamanetin demonstrated high binding affinities compared to the co-crystallized ligand and standard antibiotics like ceftaroline. Uvarinol exhibited the highest binding affinity at both sites, with a docking score of -14.94 kcal/mol and a predicted inhibition constant (Ki) of 0.01 nM. Molecular dynamics simulations further confirmed the robust stability of Uvarinol and Dichamanetin, as indicated by consistently lower RMSD values relative to the co-crystallized ligand. Pharmacokinetic predictions revealed favorable drug-likeness and low toxicity, although Uvarinol showed limited gastrointestinal absorption. Conclusions: Uvarinol and Dichamanetin show promise as dual-site PBP2a inhibitors, offering a novel strategy to combat MRSA resistance. Their structural and pharmacokinetic properties make them viable candidates for further development, though experimental validation and formulation optimization are necessary to overcome bioavailability challenges.

Discovery of a novel 4-pyridyl SLC-0111 analog targeting tumor-associated carbonic anhydrase isoform IX through tail-based design approach with potent anticancer activity

Introduction: Carbonic anhydrase IX (CA IX) is a tumor-associated enzyme involved in cancer progression and survival. Targeting CA IX with selective inhibitors like SLC-0111 has shown therapeutic potential. This study aimed to develop a novel 4-pyridyl analog (Pyr) of SLC-0111 with enhanced anticancer activity. Methods: Pyr was synthesized using a tail-based design and characterized by NMR. Its cytotoxicity was tested against cancer and normal cell lines. CA inhibition, cell cycle effects, apoptosis induction, and protein expression changes were evaluated. Molecular docking and ADMET predictions assessed binding and drug-like properties. Results and Discussion: Pyr showed selective cytotoxicity toward cancer cells and potent CA IX inhibition. It induced G0/G1 arrest, apoptosis, and modulated p53, Bax, and Bcl-2 levels. Docking confirmed strong CA IX binding, and ADMET analysis indicated good oral bioavailability. These results support Pyr as a promising anticancer candidate.

Nitrile-tolerant Iridium-catalysed Hydrogen Isotope Exchange

Isotopically labelled molecules are vital tools within drug discovery and are used extensively to assess a given candidate's absorption, distribution, metabolism, excretion, and toxicity (ADMET) profile. Related to this, transition metal-catalyzed hydrogen isotope exchange (HIE) has become a prominent technique for the rapid and selective late-stage installation of a deuterium or tritium label. Despite having a generally wide applicability, the current state-of-the-art in this specific field is limited when particularly co-ordinating motifs are present within a given molecule to be labelled. For example, the exceptional binding strength and sterically unencumbered nature of the nitrile functionality leads to inhibition of catalyst turnover, and has hindered the development of efficient methods for the HIE of nitrile-containing molecules. Herein, in silico solvent binding energy parameter approaches have been disclosed which have facilitated the discovery of uniquely tolerant neutral iridium catalyst species that demonstrate a significantly lower binding strength with nitrile functionality. In turn, we describe the first effective nitrile-tolerant HIE methodology enabled via ortho-directed C(sp2)-H activation using air- and moisture-stable iridium pre-catalysts of the type Ir(COD)(NHC)Cl under an atmosphere of deuterium gas. This methodology proceeds under mild and practically accessible reaction conditions with a range of directing groups, including heterocycles, ketones, and amines, with this class of catalyst also shown to be applicable towards bioactive molecules, resulting in products with high levels of isotopic labelling.

Combating Malaria: Targeting the Ubiquitin-Proteasome System to Conquer Drug Resistance

Malaria primarily affects developing nations and is one of the most destructive and pervasive tropical parasite infections. Antimalarial drug resistance, characterized by a parasite's ability to survive and reproduce despite recommended medication doses, poses a significant challenge. Along with resistance to antimalarial drugs, the rate of mutation a parasite undergoes, overall parasite load, drug potency, adherence to treatment, dosing accuracy, drug bioavailability, and the presence of poor-quality counterfeit drugs are some of the contributing factors that elicit opposition to treatment. The ubiquitin-proteasome system (UPS) has become a promising drug target for malaria because of its central importance in the parasite's life cycle and its contribution to artemisinin resistance. Polymorphisms in the Kelch13 gene of Plasmodium falciparum are the best-known markers for artemisinin resistance and are associated with a highly active UPS. Certain proteasome inhibitors, which are the other key players of the UPS, have demonstrated activity against malarial parasites and the ability to work with artemisinin. This work describes how, through targeting the UPS, the greater effectiveness of antimalarial drugs-especially where there is strong resistance-can be achieved, which contributes to overcoming the drug resistance phenomenon in malaria.

Silver N-Heterocyclic Biscarbene Complexes: Potent Inhibitors of Thioredoxin Reductase with Anticancer Activity in Vitro and in Vivo

Silver N-heterocyclic carbene (NHC) complexes are known to form biscarbene species from monocarbene analogs in protic polar solvents. However, the effect of the respective species of silver NHC complexes on their biological activity against bacteria or cancer cells has not been systematically explored, either in vitro or in vivo. The direct and simple conversion of monocarbene silver N-heterocyclic carbene (NHC) halide complexes (NHC)AgX, (X=Cl, Br) 1 a/b-5 a/b to their biscarbene analogues (NHC)2AgX 1 c/d-5 c/d is reported. The biscarbenes demonstrated generally lower activity against bacteria compared to the monocarbene complexes; however, both types showed similar activity against tumor cells and a non-tumor reference cell line. Selected mono- and biscarbene complexes 3 a and 3 c showed similar strong inhibitory effects on thioredoxin reductase in vitro and in cellulo and had a similar level of metal uptake into A549 cells. The subsequent evaluation of their effects in vivo revealed relatively low toxicity and high antitumoral efficacy of both selected complexes in mice. The biscarbene silver organometallic 3 c showed the most pronounced reduction of tumor growth in animals. The results indicate that both (NHC)AgX and (NHC)2AgX complexes could trigger their anticancer activity as biscarbene complexes, making this the preferred form for future anticancer metallodrug development.

Electrochemically Driven Site-Selective N-Hydroxymethylation of Indoles and Derivatives

Described herein is a facile electrochemical strategy for the generation of formaldehyde from N,N-dimethylacetamide (DMA) and water (H2O) toward a direct and site-selective N-hydroxymethylation of indoles and derivatives. Mechanistic studies suggested that N-(hydroxymethyl)-N-methylacetamide generated in situ from DMA/H2O under electrochemical conditions serves as a formaldehyde surrogate. The developed methodology features mild, base- and metal catalyst-free conditions. The reaction can accommodate a broad range of substrate scopes and offers an alternative route to access a series of N-hydroxymethylated indole, bis-indole, carbazole, and indazole derivatives. A gram-scale synthesis was demonstrated to show the scaled-up applicability of this transformation.

Delineating the tryptophan-galactosylamine conjugate mediated structural distortions in Aβ42 protofibrils

Amyloid-β (Aβ) fibrillation into neurotoxic soluble oligomers and mature fibrils is mainly responsible for the etiology of Alzheimer's disease (AD). A recent study revealed 61% disaggregation of the pre-formed Aβ42 fibrils upon incubating with a highly soluble tryptophan-galactosylamine conjugate, WGalNAc. WGalNAc displayed no toxicity and increased the viability of SH-SY5Y cells up to 62.9 ± 2% with an EC50 value of 2.3 μM against Aβ42 pre-formed fibrils. However, the key interactions and disruptive mechanism of WGalNAc against Aβ fibrils remain elusive. Thus, mechanistic insights into the disruptive potential of WGalNAc against Aβ42 protofibrils (PDB: 5OQV) were examined using molecular dynamics (MD) simulations. The molecular docking depicted a favourable binding energy (-6.60 kcal mol-1) and interaction of WGalNAc with the central hydrophobic core (CHC) region of chain A of the 5OQV protofibril. The MD simulations depicted that WGalNAc disrupted the contacts among Ala2, Phe4, Leu34, and Val36 in the hydrophobic core 1 of the 5OQV protofibril responsible for maintaining the stability of the LS-shaped 5OQV protofibril. WGalNAc binds favourably to the 5OQV protofibril (ΔGbinding = -21.76 ± 2.40 kcal mol-1) with a significant contribution from the van der Waals interaction term. Notably, the binding affinity between the neighbouring chains of the 5OQV protofibril was significantly reduced from -134.31 ± 11.12 to -121.88 ± 1.95 kcal mol-1 upon the incorporation of WGalNAc, which is consistent with the ThT kinetic results that revealed disaggregation of the pre-formed Aβ42 fibrils upon incubating with WGalNAc. The in silico ADMET properties of WGalNAc showed its ability as a promising therapeutic candidate due to its blood-brain barrier (BBB) permeability, extended half-life, and non-toxic profile. The MD simulations illuminated the binding interactions of WGalNAc with the 5OQV protofibril and provided mechanistic insights into the WGalNAc-mediated structural distortions in the 5OQV protofibril.

Pharmacochemical Studies of Synthesized Coumarin-Isoxazole-Pyridine Hybrids

Several new coumarin-isoxazole-pyridine hybrids were synthesized through a 1,3-dipolar cycloaddition reaction of nitrile oxides, prepared in situ from pyridine aldehyde oximes, with propargyloxy- or propargylaminocoumarins in moderate-to-good yields. Synthetic modifications were applied using (diacetoxyiodo)benzene (PIDA) at room temperature, microwave irradiation, or tert-butyl nitrite (TBN) under reflux. Coumarin, isoxazole, and pyridine groups were selected for hybridization in one molecule due to their biological impact to inhibit lipid peroxidation and an enzyme implicated in inflammation. Preliminary in vitro screening tests for lipoxygenase (LOX) inhibition and anti-lipid peroxidation for the new hybrids were performed. A discussion on the structure-activity relationship is presented. Compounds 12b and 13a were found to be potent LOX inhibitors with IC50 5 μΜ and 10 μΜ, respectively, while 12b presented high (90.4%) anti-lipid peroxidation. Furthermore, hybrids 12b and 13a exhibited moderate-to-low anticancer activities on HeLa, HT-29, and H1437 cancer cells.

Investigation of the Possible Antibacterial Effects of Corticioid Fungi Against Different Bacterial Species

Extracts from 58 species of corticioid fungi (phylum Basidiomycota), mainly belonging to the orders Hymenochaetales, Polyporales and Russulales, were tested for their inhibitory activity against five species of bacteria: Corynebacterium striatum, Haemophilus influenzae, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus. Twenty-four of the species we analyzed in this study were tested for antibacterial activity for the first time. The fruiting bodies of the fungi were collected from dead wood in the forests of north-eastern Poland, and macerated in methanol. Dried extracts were redissolved in dimethyl sulfoxide and applied to broth cultures of the bacteria, which were then inoculated on agar plates. Noblesia crocea demonstrated moderate inhibitory activity against all five tested bacteria; Amylocorticium subincarnatum, Laxitextum bicolor, Peniophora laeta, P. rufomarginata, Phanerochaete sordida, and Xylobolus frustulatus inhibited four bacterial species. The extracts from 14 fungal species tested were moderately active against only two bacteria, P. aeruginosa and C. striatum; 17 species were active against C. striatum only. The full inhibition was observed with concentrations of extract 25 or 50 mg/mL.

The evolution and application of RNA-focused small molecule libraries

RNA structure plays a role in nearly every disease. Therefore, approaches that identify tractable small molecule chemical matter that targets RNA and affects its function would transform drug discovery. Despite this potential, discovery of RNA-targeted small molecule chemical probes and medicines remains in its infancy. Advances in RNA-focused libraries are key to enable more successful primary screens and to define structure-activity relationships amongst hit molecules. In this review, we describe how RNA-focused small molecule libraries have been used and evolved over time and provide underlying principles for their application to develop bioactive small molecules. We also describe areas that need further investigation to advance the field, including generation of larger data sets to inform machine learning approaches.

Where lung cancer and tuberculosis intersect: recent advances

Lung cancer (LC) and tuberculosis (TB) represent two major global public health issues. Prior evidence has suggested a link between TB infection and an increased risk of LC. As advancements in LC treatment have led to extended survival rates for LC patients, the co-occurrence of TB and LC has grown more prevalent and poses novel clinical challenges. The intricate molecular mechanisms connecting TB and LC are closely intertwined and many issues remain to be addressed. This review focuses on resemblance between the immunosuppression in tumor and granuloma microenvironments, exploring immunometabolism, cell plasticity, inflammatory signaling pathways, microbiomics, and up-to-date information derived from spatial multi-omics between TB and LC. Furthermore, we outline immunization-related molecular mechanisms underlying these two diseases and propose future research directions. By discussing recent advances and potential targets, this review aims to establish a foundation for developing future therapeutic strategies targeting LC with concurrent TB infection.

A one-pot multicomponent tandem reaction for the rapid synthesis of 2-amino-3-benzylindoles

The simultaneous introduction of two functional groups into molecules via a one-pot process is of great importance for the synthesis of complex molecules. However, this remains a challenging task due to the need for precise control of regio- and chemo-selectivity. In this paper, we present a novel oxidative cross-dehydrogenation coupling (CDC) reaction that selectively introduces two nucleophiles at the C2,3-positions of indoles, thereby constructing the C-N and C-C bonds simultaneously in one pot. This method offers a streamlined and efficient approach for functionalizing indoles with high selectivity, expanding the synthetic toolbox for the construction of complex organic frameworks.

Fluorescent PyrAte-(S)-citalopram conjugates enable imaging of the serotonin transporter in living tissue

Fluorescent labeling techniques have enabled the visualization of various biomolecules, cellular structures, and their associated physiological processes. At the same time, there remains a demand for developing novel fluorescent compounds possessing unique chemical properties for biological imaging. A recently developed class of fluorophores, termed PyrAtes, displays optimal brightness and large Stokes shifts that are ideal for fluorescence microscopy. Herein, we report the development of PyrAte-based fluorescently labeled ligands that bind to the serotonin transporter (SERT), a membrane transport protein important for neurotransmitter homeostasis, which hitherto has not been visualized in its native environment using fluorescent small molecules. The design of a PyrAte fluorophore attached to (S)-citalopram, a selective serotonin reuptake inhibitor, resulted in the synthesis of two fluorescent drug conjugates varying in linker length: PYR-C6-CIT and PYR-C3-CIT. Docking and molecular dynamics experiments are performed to estimate their binding affinities to SERT. Our in vitro experiments confirm both compounds are effectively binding to SERT overexpressed in human embryonic kidney 293 cells, with the shorter conjugate displaying improved SERT affinity and membrane staining properties. Furthermore, ex vivo imaging of endogenous SERT was demonstrated in acute mouse brain slices using two-photon microscopy. The large Stokes shift of the PyrAte fluorophore enables simultaneous detection of its own fluorescence signal at 500 nm along with that of a yellow fluorescent protein-based serotonergic marker. Our findings provide novel tools for unprecedented SERT visualization and establish the utility of PyrAtes for the selective staining of membrane proteins in live cells and tissue.

Cysteine-selective [188Re]Re(v) radiolabelling of a Nanobody® for targeted radionuclide therapy using a "chelate-then-click" approach

In this study, we present the first reported use of bioorthogonal click chemistry with rhenium-188 for radiolabelling of an anti-c-Met VHH Nanobody®. We employed a "chelate-then-click" strategy, wherein a bifunctional chelator was designed in two parts, which were subsequently joined post-labelling and post-conjugation via the strain-promoted azide-alkyne cycloaddition (SPAAC) reaction. Cysteine-selective conjugation of the VHH was achieved through thiol-Michael addition, forming a VHH-DBCO construct. Radiolabelling of the azide-functionalised chelator with [188Re]Re(v) was optimised to achieve a radiochemical conversion of ∼70%, despite challenges associated with maintaining the azide functionality under reducing conditions. The final product, [188Re]Re-VHH, demonstrated high radiochemical purity and good in vitro stability over 48 h. In vitro cell-binding studies against U87MG and BxPC3 cell lines proved the retention of c-Met binding post-labelling. In vivo biodistribution studies on mice bearing BxPC3 tumour xenografts, however, exhibited suboptimal tumour uptake, likely a result of the low molar activity (1.4-3.3 MBq nmol-1) of the radioconjugate. This work illustrates the potential of bioorthogonal click chemistry for radiolabelling biomolecules with 188Re, although further optimisation or alternative radiolabelling strategies to enhance the molar activity are necessary to improve pharmacokinetics.

Identification of 6,8-ditrifluoromethyl halogenated phenazine as a potent bacterial biofilm-eradicating agent

Bacterial biofilms are surface-attached communities consisting of non-replicating persister cells encased within an extracellular matrix of biomolecules. Unlike bacteria that have acquired resistance to antibiotics, persister cells enable biofilms to demonstrate innate tolerance toward all classes of conventional antibiotic therapies. It is estimated that 50-80% of bacterial infections are biofilm associated, which is considered the underlying cause of chronic and recurring infections. Herein, we report a modular three-step synthetic route to new halogenated phenazine (HP) analogues from diverse aniline and nitroarene building blocks. The HPs were evaluated for antibacterial and biofilm-killing properties against a panel of lab strains and multidrug-resistant clinical isolates. Several HPs demonstrated potent antibacterial (MIC ≤ 0.39 μM) and biofilm-eradicating activities (MBEC < 10 μM) with 6,8-ditrifluoromethyl-HP 15 demonstrated remarkable biofilm-killing potencies (MBEC = 0.15-1.17 μM) against Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus clinical isolates. Confocal microscopy showed HP 15 induced significant losses in the polysaccharide matrix in MRSA biofilms. In addition, HP 15 showed increased antibacterial activities against dormant Mycobacterium tuberculosis (Mtb, MIC = 1.35 μM) when compared to replicating Mtb (MIC = 3.69 μM). Overall, this new modular route has enabled rapid access to an interesting series of potent halogenated phenazine analogues to explore their unique antibacterial and biofilm-killing properties.

Comparative life cycle assessment of the fabrication of visible-light-driven photocatalytic TiO2 - Carbon dots nanocomposites for wastewater treatment

TiO2 nanoparticles are promising photocatalysts due to their oxidizing strength and inertness. However, their inability to efficiently absorb visible light limits industrial applications that could use sunlight. The addition of carbon dots to TiO2 has been recently shown to have the potential to address this issue by enhancing the visible-light-driven photocatalytic efficiency of the resulting nanocomposites. However, concrete data on their sustainable development and fabrication is lacking. Herein, we performed a life cycle assessment (LCA) study to understand the environmental impacts of different TiO2‑carbon dots nanocomposites with enhanced visible-light-driven photocatalytic activity. It was found that the nanocomposites with the highest photocatalytic activity were the ones whose synthesis was associated with lower environmental impacts. Furthermore, the carbon dots generally have little to moderate contributions to most impact categories, except for marine eutrophication. Finally, the most critical parameter was found to be the source of TiO2 for the nanocomposites.

Intercepting a Mycobacterial Biosynthetic Pathway with Covalent Labeling

The mycobacterial cell envelope plays both infectious and protective roles. Understanding its structure is crucial for unlocking the molecular basis underlying these functions. Studying glycans, the primary components of the cell envelope, is challenging due to their limited native functional handles for chemoselective modification. New labeling methods exploit biorthogonal chemistry, using small molecule mimics that intercept cellular metabolism or late-stage glycan biosynthesis. However, these strategies can have practical limitations, including probe delivery and effectiveness. An ideal small molecule probe should be easily deployed and exploit the critical enzyme-substrate relationships of natural substrates. To this end, we developed a "probegenic" strategy to label mycobacteria. Our approach eliminates the need for explicit substrate mimicry, as the relevant functionality is revealed by a target enzyme. Specifically, we synthesized an azide-substituted trans-β-lactone probe (AzLac), which adopts a substrate-like structure upon covalent enzyme labeling. This probe is incorporated by mycolyltransferases into a core mycobacterial cell envelope glycan, including in the pathogen Mycobacterium tuberculosis. Unlike other probes of the cell envelope, AzLac facilitates selective covalent labeling of the inner leaflet of the mycomembrane. Using Corynebacterium glutamicum mycolyltransferase deletion strains, we implicated Cmt2 as the primary mycolyltransferase target. We leveraged the ability to modify the cell envelope by demonstrating that AzLac could be used to attach a DNA barcode to mycobacteria, which would help track infection dynamics. Thus, we expect AzLac will be a valuable means of monitoring and tracking the mycobacterial cell envelope. Moreover, we anticipate masking and revealing recognition motifs in probes can be applied to diverse cellular targets.

Structural regression modelling of peptide based drug delivery vectors for targeted anti-cancer therapy

Drug resistance in cancer poses a serious challenge in finding an effective remedy for cancer patients, because of the multitude of contributing factors influencing this complex phenomenon. One way to counter this problem is using a more targeted and dose-limiting approach for drug delivery, rather than relying on conventional therapies that exhibit multiple pernicious side-effects. Stability and specificity have traditionally been the core issues of peptide-based delivery vectors. In this study, we employed a structural regression modelling approach in the design, synthesis and characterization of a series of peptides that belong to approximately same topological cluster, yet with different electrostatic signatures encoded as a result of their differential positioning of amino acids in a given sequence. The peptides tagged with the fluorophore 5(6)-carboxyfluorescein, showed higher uptake in cancer cells with some of them colocalizing in the lysosomes. The peptides tagged with the anti-cancer drug methotrexate have displayed enhanced cytotoxicity and inducing apoptosis in triple-negative breast cancer cells. They also showed comparable uptake in side-population cells of lung cancer with stem-cell like properties. The most-optimized peptide showed accumulation in the tumor resulting in significant reduction of tumor size, compared to the untreated mice in in-vivo studies. Our results point to the following directives; (i) peptides can be design engineered for targeted delivery (ii) stereochemical engineering of peptide main chain can resist proteolytic enzymes and (iii) cellular penetration of peptides into cancer cells can be modulated by varying their electrostatic signatures.

A Structural Insight Into Two Important ErbB Receptors (EGFR and HER2) and Their Relevance to Non-Small Cell Lung Cancer

The epidermal growth factor receptor (EGFR) family, comprising receptor tyrosine kinases (RTK) such as EGFR and HER2, plays a critical role in various signaling pathways related to cell proliferation, differentiation, and growth. EGFR overactivation due to aberrant signaling can lead to various cancers, including non-small cell lung cancer (NSCLC). To develop treatment for EGFR-related NSCLC, several tyrosine kinase inhibitors (TKIs) were designed: gefitinib, erlotinib, as first-generation; neratinib, dacomitinib as second-generation; osimertinib, lazertinib as third-generation, as examples. However, due to the acquired resistance by the mutations such as EGFRT790M and EGFRC797S together with the exon 20 insertion mutations, these drugs do not provide promising results for NSCLC patients. The development of fourth-generation inhibitors like EAI045 and further innovative drugs to overcome this resistance problem is a must to cure EGFR-related NSCLC. Among these, pyrazoline-thiazole scaffolds are found effective as EGFR-HER2 inhibitors against NSCLC, making them promising drug candidates. Although structures obtained so far for the EGFR family provide meaningful insights into the mechanisms, the quality and the quantity of the EGFR family structures are insufficient to elucidate the complete structures and functions to overcome NSCLC. This review evaluates the structures of EGFR-HER2 and investigates their relation to NSCLC.

Innovative Multitarget Organoselenium Hybrids With Apoptotic and Anti-Inflammatory Properties Acting as JAK1/STAT3 Suppressors

Herein, we report the design, synthesis, and characterization of novel organoselenium (OSe) hybrids (5-19) via modifications of the lead, N-(4-selaneylphenyl)-2-selaneylacetamide. The OSe-based thiazol 9 showed the highest growth inhibition % (GI%) of 64.72% relative to the positive reference doxorubicin (DOX), with a GI% of 79.5%. Furthermore, the novel OSe derivatives showed low GI% values compared to the normal cell lines employed, demonstrating their selectivity. The OSe tethered N-chloroacetamide 5 and Schiff base 19 showed a cytotoxic effect with an IC50 of (25.07 and 11.61 µM), respectively, against the A549 tumor cell line and IC50 of (34.22 and 20.12 µM), respectively, against the HELA cancer cell line. Enzyme-linked immunosorbent assay to study the JAK1 and the STAT3 inhibitory potentials of OSe compounds 5 and 19 in the A549 cancer cells both showed promising inhibitory activities with IC50 values of 25.07 and 11.61 µM, respectively. Protein expression analysis on the A549 cancer cell line on OSe compounds 5 and 19 showed upregulation of P53, BAX, and Caspases 3, 6, 8, and 9 as apoptotic proteins. However, both candidates expressed downregulation of the antiapoptotic proteins (BCL2, MMP2, and MMP9). Moreover, OSe compounds 5 and 19 described the downregulation of the examined inflammatory proteins: COX2, IL-6, and IL-1β. In addition, OSe compound 19 showed potential cell cycle arrest at the G0, S, and G2-M layers, with an increase in cellular levels. Finally, molecular docking studies of OSe compound 19 showed the most promising inhibitory potential toward the JAK1 and STAT3 target receptors, with binding scores and interactions exceeding that of the cocrystallized inhibitor of JAK1.

In silico analysis of novel Triacontafluoropentadec-1-ene as a sustainable replacement for dodecane in fisheries microplastics: Molecular docking, dynamics simulation and pharmacophore studies of acetylcholinesterase activity

Plastics play an essential role in modern fisheries and their degradation releases micro- and nano-sized plastic particles which further causes ecological and human health hazards through various environmental contamination pathways and toxicity mechanisms, which can cause respiratory problems, cancer, reproductive toxicity, endocrine disruption and neurological effects in humans. This study utilized various bioinformatics tools through multi-step computational analyses to investigate the interactions between prevalent fisheries microplastics and the key protein receptor acetylcholinesterase (AChE), which is associated with neurotoxicity, as it can interfere with nerve impulses and muscle control. Our results indicate that the binding of seven polymers within AChE's active site, with dodecane and polypropylene exhibited highest affinity with hydrogen bonding were observed through Molecular docking of different program (PyRx) and servers (CB-Dock, eDock) then the stability of AChE-dodecane and AChE-polypropylene complexes were observed through MD simulations for 100 ns. Further analysis of dodecane was done by using pharmacophore modelling and virtual screening. The pharmacophore model of dodecane is based on six hydrophobic rings. Using this model, we screened among thousands of substrates form (CMNPD, COCONUT, NPASS, NANPDB, and ZINC) database and identified fifty highly similar candidates that align with dodecane's structure and interaction with acetylcholinesterase (AChE). The compound triacontafluoropentadec-1-ene exhibited highest binding affinity (score: -9.6) which was further confirmed through molecular dynamics for 100 ns. The key finding for this study is triacontafluoropentadec-1-ene as a promising alternative to dodecane, and the study highlights that the integrated in silico framework presents a valuable computational model for guiding future guidelines on environmental safety through prioritizing constituents and accelerated discovery of alternatives. These findings will help us identify the most hazardous plastics through ranking and characterizing the substance for sustainably "greening" fisheries worldwide. The study forecasts the groundwork of these compounds, which may be able to reduce the environmental toxicity of microplastics in future.

Hyaluronic acid modified metal-organic frameworks loading cisplatin achieve combined chemodynamic therapy and chemotherapy for lung cancer

As one of the most commonly used chemotherapeutic agents in clinical practice, cisplatin is unable to selectively accumulate in tumor tissue due to its lack of targeting ability, leading to increased systemic toxicities. Additionally, the effectiveness of monotherapy is greatly limited. Therefore, the development of new cisplatin-based drug delivery systems is essential to improve the effectiveness of tumor treatment. In this study, an iron-based metal-organic framework (MOF) was synthesized to encapsulate cisplatin, and then coated with hyaluronic acid (HA) to create a MOF-based nanoplatform called MPt@HA NPs. This novel nanoplatform achieved the combination of chemodynamic therapy (CDT) with targeted chemotherapy for the treatment of lung cancer. The results showed that MPt@HA NPs have stronger cytotoxicity compared to conventional doses of cisplatin due to the generation of reactive oxygen species (ROS) through the Fenton reaction and DNA damage caused by cisplatin. Therefore, MPt@HA NPs effectively inhibit the tumor growth and prolong the median survival of tumor-bearing mice. Therefore, the MOF-based nanoplatform MPt@HA NPs may present a new option for multi-modal therapy of solid tumors.

Optimizing the discovery bioanalysis strategy for macrocyclic peptides

Macrocyclic peptides (MCPs) have remained a compelling modality in drug discovery and development, with many successful marketed drugs. Their unique molecular structure and ADME properties have posed bioanalytical challenges that cannot be fully addressed with conventional small molecule LC-MRM assays. In this work, we developed and optimized a high-throughput discovery bioanalytical strategy for MCPs with 16 marketed MCP drugs. By evaluating ten different sample extraction methods based on the recovery and matrix effect, we identified that the protein precipitation extraction with MeOH/ACN (1/1 v/v) with 0.5% FA outperformed the other sample extraction methods, achieving 80% recovery for 80% of the MCP drugs and 90% matrix effect for 90% of the MCP drugs. By assessing the sensitivity of the targeted-selected ion monitoring (t-SIM) and parallel reaction monitoring (PRM) on the Orbitrap HRMS and comparing with the conventional LC-MRM, we concluded that the t-SIM provided comparable sensitivity with MRM (LOQ at 1~3 ng/mL for the majority of the MCP drugs), with the extra benefits of minimal method development and high post-acquisition flexibility in data processing. The optimized bioanalytical strategy was applied to various biological matrices and displayed performance that met the quantitation requirements for discovery bioanalysis.

Discovery of the potential of cholesterol-lowering human CYP7 enzymes as biocatalysts for the production of C7 hydroxylated steroids

Steroidal C7 alcohols and their esters are perspective agents in drug discovery. In addition, hydroxylation at C7 position could allow further modification of steroidal moiety. Such transformation is performed easily by the enzymes. Human steroid 7α-hydroxylases CYP7A1 and CYP7B1 are key enzymes taking part in the biotransformation of cholestanes, androstanes, pregnanes. In the article, we are focusing on the results of in vitro screening of a library of modified steroids toward CYP7 enzymes. A couple of compounds were found to express the affinity for binding to the enzymes, comparable with corresponding values for CYP7 natural ligands. Among them are 17-substituted androstane derivatives with N-containing pyridine ring and enone derivative of lithocholic acid, which bound by human CYP7A1, and D-seco and C16 oxime androstanes, which were identified as novel CYP7B1 ligands. Screening results revealed that both enzymes bind with high affinity a well-known drug abiraterone: in the case of CYP7A1 substrate-like binding mode was detected, with the formation of monohydroxylated product, while in case of CYP7B1 inhibitor-like binding was observed. Since CYP7 enzymes convert some of the studied compounds into their 7-hydroxy derivatives, potential of these enzymes as perspective regio- and stereoselective biocatalysts for obtaining C7 hydroxylated steroids could be assumed.

The Current Landscape of 1,2,3-triazole Hybrids With Anticancer Therapeutic Potential: Part II

Chemotherapy has been identified as a validated and critically important strategy for the treatment of cancer, but multidrug resistance and serious side effects remain grand challenges for effective cancer therapy. This highlights the urgent need for the development of alternative chemical entities that can modulate more than one biological target with high specificity and multitargeted mechanism of action in the disease progression pathway. 1,2,3-Triazole hybrids have the potential to act on dual/multiple targets in cancer cells simultaneously and possess potent broad-spectrum activity against various cancers, including drug-resistant forms. Thus, 1,2,3-triazole hybrids are valuable scaffolds in the treatment and eradication of cancer. This review provides a comprehensive overview of the evolving landscape of 1,2,3-triazole hybrids with their in vitro and in vivo anticancer potential, and the structure-activity relationships as well as mechanisms of action are also discussed, covering articles published from 2021 onward.

Recent in vitro advances in the ocular antimicrobial agents against Acanthamoeba

This review examines the advancements in antimicrobial drug discovery with in vitro assays for Acanthamoeba, highlighting the efficacy of current topical antimicrobial agents. In recent decades, the treatment and diagnosis of Acanthamoeba keratitis (AK) have presented clinical challenges. Clinicians often rely on clinical judgment, risk factors, and patient travel history to guide initial treatment decisions. The clinical presentation of AK frequently coincides with bacterial and fungal keratitis, leading to delays in diagnostic confirmation. This review compiles a list of commonly used antimicrobial agents that may be useful in controlling and preventing Acanthamoeba and other microbial infections during the diagnostic waiting period. Due to their unique life cycle, consisting of both trophozoite and cyst stages, amoebae exhibit resistance to various clinical drugs. Current research efforts are focused on identifying alternative and effective treatment options. Despite the ongoing characterization of various cytocidal agents from natural and synthetic sources, chlorhexidine gluconate (CHG) and polyhexamethylene biguanide (PHMB) have emerged as the most effective therapies for AK. Drawing from previous studies, we catalog several commonly used antimicrobial agents that may enhance the efficacy of PHMB and CHG while also preventing other microbial infections. These alternative agents present promising options for treating AK cases. This review evaluates progress in anti-amoebic drug discovery, focusing on antibiotics and cataloging their activity at different stages of Acanthamoeba.

Development of indole hybrids for potential lung cancer treatment - part II

Lung cancer has become the most prevalent cancer for the past three decades, and the 5-years survival rate of lung cancer is only ~20% nowadays. Chemotherapy is the mainstay of lung cancer therapy, especially for non-small cell lung cancer. However, drug resistance represents a principal cause of therapeutic failure in non-small cell lung cancer leading to therapeutic insensitivity, tumor recurrence, and disease progression. Indole hybrids have the potential to conquer drug resistance, enhance efficacy, reduce adverse events, and improve pharmacokinetic properties due to their capacity to inhibit multiple targets simultaneously. Moreover, indole hybrids osimertinib, mobocertinib, cediranib, and vizimpro are currently applied in clinics for lung cancer therapy, demonstrating that indole hybrids are valuable scaffolds in the treatment and eradication of lung cancer. This review provides a comprehensive overview of the evolving landscape of indole hybrids with the in vitro and in vivo efficacy against lung cancer, and the structure-activity relationships as well as mechanisms of action are also discussed, covering articles published from 2021 onward.

Unlocking the power of imidazoquinolines: recent advances in anticancer and immunotherapeutic strategies

The challenges in drug discovery aiming to mitigate cancer progression are the thrust area of scientific research for several decades. Since the advent of heterocyclic chemistry, drug discovery programs have made significant achievements that lead to the development of numerous drugs with broad spectrum of potencies, contributing to both diagnostic and therapeutic advancements. Till date, efforts to discover more potent and efficient drug candidates are underway to minimize adverse side effects of existing chemotherapeutics. In view of the above, small-molecule agonists that can interact with different immune modulators like toll like receptor-7 (TLR-7) and TLR-8 are being investigated and explored. These candidates are expected to display profound effect on anti-tumoral activity by enhancing the production of proinflammatory cytokines. Recently, numerous imidazoquinoline derivatives with proven TLR agonist activities have emerged as promising anticancer therapeutics. With advancements in technology and the evolution of new scopes in drug discovery, different strategies are being adopted, particularly with the help of nanotechnology, immune-technology, combination drug chemistry, etc., to curb the progression of various types of cancers. Herein, the novel strategies for cancer therapeutics with imidazoquinolines reported in the last 5 years, their structure-activity relationship along with important synthetic schemes for important TLR agonists, are discussed.

Light-induced chemistry for protein functionalisation

Derivatising biomolecules like monoclonal antibodies with drugs or imaging agents, whilst preserving their bioactivity, is a challenging task. Protein functionalisation ideally requires methods that operate under mild conditions, are rapid, efficient (high yielding), chemoselective or site-specific, and importantly, non-denaturing. A broad collection of thermally mediated reagents for direct labelling using protein-based reactivity, or bioorthogonal strategies, has been developed, but arguably the most exciting opportunities lie in the application of photochemistry to create new covalent bioconjugate bonds. With current chemical methods for auxochromic tuning of the spectral features of photoactive groups, and with cheap, high-powered light-emitting diodes with precise emission properties, it has never been easier to explore the use of light-induced chemistry for making protein-based bioactive molecules. In biomedicine, the nature of the covalent bond to the protein can have a dramatic impact on the physicochemical properties and performance of the protein-conjugate. Photochemical methods provide access to new types of covalent linkages on protein with the potential to fine-tune biological interactions, leading to improvements in target uptake, binding specificity, metabolic processing, and washout kinetics in vivo. This perspective/review highlights recent advances in the development of photoactive reagents for protein labelling. We also discuss the experimental conditions and critical requirements to implement light-induced synthesis of functionalised protein-conjugates in aqueous media effectively.

Local necrosis induced by intralesional treatment with amphotericin B- deoxycholate

Intralesional (IL) treatment of cutaneous leishmaniasis with pentavalent antimonials has greatly reduced the systemic toxicity imposed by the conventional intramuscular and intravenous injections. Nevertheless, therapeutic failure with antimonials can occur due to drug resistance and/or short retention in the inflamed skin. Here we evaluated the safety and efficacy of IL treatment with injectable amphotericin B (AmB), a powerful antileishmanial drug that is less prone to drug resistance, but due to its amphiphilic nature is formulated with the ionic detergent sodium deoxycholate (Deox). Thus, Deox-AmB reconstituted with injectable water as directed was evaluated in vivo in L. amazonensis - infected mice in comparison with equivalent Deox or AmB alone. On days 7, 10, 14 and 17 of infection, the infected ears were injected with 10, 50 or 150 μg of AmB/dose. After 34 days of infection, AmB was most effective in killing the parasites at 150 μg/dose. However, at that effective dose Deox-AmB produced severe skin necrosis due to Deox. Our findings indicate that the necrotizing effect of Deox should be considered before using commercial Deox-AmB formulations containing this stabilizing agent for intralesional treatment.

Design, synthesis and biological evaluation of new class of pyrazoles-dihydropyrimidinone derivatives as bone anabolic agents

This study explores a series of twenty-four newly synthesized pyrzole-dihydropyrimidinone hybrids as potential bone anabolic agents. Initially, an alkaline phosphatase assay, a common marker of bone formation, was used to screen all compounds for their ability to stimulate osteogenic potential. Initial screening identified three promising candidates (5f, 5u and 5w) that were subsequently confirmed to be non-toxic to osteoblasts. Further investigation revealed that compound 5w displayed the most potent osteoanabolic effect, promoting osteoblast differentiation and upregulating mRNAs expression of osteogenic gene. Based on the promising in vitro and in vivo activity, structure-activity relationship (SAR) analysis revealed a furan ring on the dihydropyrimidinone unit and electron-donating groups on the N-phenyl ring of the pyrazole moiety to be crucial for osteogenic activity. Additionally, molecular docking, favorable pharmacokinetic properties and In silico ADME predictions suggest potential oral bioavailability. These findings establish the pyrazole-dihydropyrimidinone scaffold as a promising hit for developing a new class of orally active bone anabolic agents.

Fundamental properties and principal areas of focus in antibody-drug conjugates formulation development

Antibody-drug conjugates (ADCs) have emerged as a rapidly expanding class of therapeutics driven by their superior specificity and clinical efficacy. 14 out of 16 commercially approved ADCs are formulated as lyophilized forms because ADC is generally considered to be less stable than unmodified antibody. The formulation development for ADCs, particularly liquid formulation, presents unique challenges due to their intricate structural complexity, physicochemical properties, and degradation pathways. This review provides the first comprehensive analysis of formulation strategies employed in commercial ADCs. Furthermore, this review discusses the key areas of focus for ADCs throughout the formulation development workflow, spanning from the initial formulation development to the final stage of drug product manufacturing. In addition, we identify and analyze the distinctive technical challenges in ADC formulation development compared to unconjugated antibody, while proposing potential solutions to these challenges. Finally, we offer strategic perspectives on future directions in ADC formulation development to advance this promising therapeutic modality.

The "three body solution": Structural insights into molecular glues

Molecular glues are small molecules that nucleate novel or stabilize natural, protein-protein interactions resulting in a ternary complex. Their success in targeting difficult to drug proteins of interest has led to ever-increasing interest in their use as therapeutics and research tools. While molecular glues and their targets vary in structure, inspection of diverse ternary complexes reveals commonalities. Whether of high or low molecular weight, molecular glues are often rigid and form direct hydrophobic interactions with their target protein. There is growing evidence that these hotspots can accommodate multiple ternary complex binding modes and enable targeting of traditionally undruggable targets. Advances in screening from the molecular glue degrader literature and insights in structure-based drug design, especially from the non-degrading tri-complex work, are likely intersectional.

The Development of Selective Chemical Probes for Serine Arginine Protein Kinase 3

The serine arginine protein kinases (SRPKs) are a family of kinases whose irregular function is implicated in cancer and viral infections. While the roles of SRPK1 and SRPK2 in disease are well established, much less is known about SRPK3. There are several studies implicating SRPK3 in breast cancer, but the mechanism is still unknown. This work describes the first-reported SRPK3 chemical probes that show excellent selectivity over the other SRPKs. 1-(4-cyanophenyl)-3-phenylurea was identified as an initial hit for SRPK3 through a kinase screen. Subsequent rounds of in silico docking, medicinal chemistry optimization, and biochemical assays were performed to increase its potency and selectivity for SRPK3. Six top compounds were identified that displayed single digit micromolar IC50 values in SRPK3 activity assays and negligible inhibition of SRPK1 or SRPK2. These six compounds demonstrated impairment of breast cancer cell viability that correlated with their biochemical IC50 values, suggesting that they can be used as tools to study the biological functions of SRPK3 in breast cancer. With an enhanced understanding of SRPK3's biological function, it may emerge as a meaningful drug target, wherein our top inhibitors could be further optimized to produce novel cancer therapeutics.

Diaryl Diimidazopyrimidine Derivatives as Potent Inhibitors of Influenza A Virus: Synthesis, Evaluation and Docking Studies

In this report, we present a new series of diaryl diimidazopyrimidine derivatives 3a-m, that have been synthesized and assessed for their in vitro antiviral activity. The derivatives were prepared through a one-step reaction involving commercially available 2,4-diamino-6-chloropyrimidine and various phenacyl bromides 2a-m, leading to the formation of the desired diaryl diimidazo- pyrimidines 3a-m with good yields. In vitro evaluations against the Influenza A H1N1 strain identified compounds 3m (SI = 73) and 3b (SI = 23) as the most potent candidates. Additionally, antimicrobial screening indicated that compounds 3d and 3j, which contain methyl and methoxy substitutions, exhibited moderate activity against Streptococcus mutans, Salmonella typhi, and Candida albicans. Molecular Docking studies of the promising compounds 3b and 3m demonstrated significant binding interactions with the M1 matrix protein (PDB ID: 5CQE) in comparison to M2 proton channel of Influenza A (PDB: 6US9), suggesting that these derivatives may be effectively targeting the M1 protein. Additionally, molecular dynamics (MD) simulations were conducted to evaluate the stability, dynamic behaviour, and binding affinity of the most potent compounds 3b and 3m. The in vitro antiviral studies, molecular docking and MD simulations data highlight the promising pharmacological potential of these analogues, paving the way for further structural optimization and development as potential antiviral agents.

WELPSA: A Green Catalyst Mediated Microwave Assisted Efficient Synthesis of Novel 5-Aminopyrazole-4-Carbonitrile Derivatives as Anticancer Agents (MCF-7, A-549) and In Silico Studies

Malononitrile, modified hydrazine, and quinoline aldehyde were combined in a one-pot reaction under microwave irradiation to create the medicinally significant family of heterocyclic scaffolds, quinoline, coumarin, thiazole, and pyrazole 4-carbonitrile derivatives with the help of green solvent as water. WELPSA (water extract of lemon peel-soaked ash) is used to speed up the reaction in a solvent-free environment, according to more environmentally friendly reaction protocols. This methodology offers several advantages like short reaction duration, green solvent synthesis, high yield, no need for chromatographic techniques, catalyst recyclability of up to five cycles, and so on. Synthesized derivatives were evaluated for anticancer potential against lung (A549) and breast cancer cell lines. Among the tested compounds, 4i and 4j exhibited remarkable anticancer activities. Further investigations using Annexin V staining and flow cytometry revealed that both compounds effectively induced apoptosis in A549 cancer cells. Compound 4i was subjected to molecular docking and dynamic studies to understand the molecular basis of their activity, which demonstrated a strong interaction with the target protein 1m17, providing insights into its mechanism of action. These findings highlight the potential of compounds 4i and 4j as promising candidates for anticancer drug development.

Innovative Pyrazole Hybrids: A New Era in Drug Discovery and Synthesis

Heterocyclic compounds that include nitrogen and their derivatives have long been regarded as excellent sources of medicinal substances. Pyrazole is a compound with two nitrogen atoms and an aromatic structure. It has several uses and intricate stereochemistry arranged in a five-membered ring. The knowledge of different pyrazole derivatives and their range of physiological and pharmacological actions has grown significantly in recent years. The scientific community has recently increasingly focused on exploring the chemistry of various pyrazole hybrids due to their enhanced biological activities. This review investigates the chemistry of these diverse pyrazole hybrids, emphasizing their synthesis and their antidiabetic, antibacterial, anticancer, antimicrobial, antioxidant, and anti-inflammatory activities. Articles published from 2014 onward with an emphasis on the last 5 years are included in this review. This review is anticipated to be useful for future investigations and innovative concepts in the pursuit of designs for creating more promising hybrids of pyrazoles.

Role of Chinese Medicine Monomers in Dry Eye Disease: Breaking the Vicious Cycle of Inflammation

Dry eye disease (DED) is a chronically inflammatory ocular surface disorder of unknown pathogenesis. Anti-inflammatory medications, artificial tears, autologous serum, and LipiFlow have been shown to be highly beneficial in alleviating symptoms. Nevertheless, these interventions often provide only short-term results and do not address the underlying problems of the disease. There is growing evidence that the risk of DED is associated with a vicious cycle of inflammation. This vicious cycle of inflammation is produced by the interaction of several factors, including tear film hyperosmolarity, tear film instability, inflammation, and apoptosis. Chinese medicine monomers, distinguished by their multicomponent and multitarget advantages, have been shown to help treat DED by modulating tear film status, and inhibiting inflammatory responses, and apoptosis, providing a new way of thinking of the management of DED in Chinese medicine.

Survival strategies of cancer cells: the role of macropinocytosis in nutrient acquisition, metabolic reprogramming, and therapeutic targeting

Macropinocytosis is a nonselective form of endocytosis that allows cancer cells to largely take up the extracellular fluid and its contents, including nutrients, growth factors, etc. We first elaborate meticulously on the process of macropinocytosis. Only by thoroughly understanding this entire process can we devise targeted strategies against it. We then focus on the central role of the MTOR (mechanistic target of rapamycin kinase) complex 1 (MTORC1) in regulating macropinocytosis, highlighting its significance as a key signaling hub where various pathways converge to control nutrient uptake and metabolic processes. The article covers a comprehensive analysis of the literature on the molecular mechanisms governing macropinocytosis, including the initiation, maturation, and recycling of macropinosomes, with an emphasis on how these processes are hijacked by cancer cells to sustain their growth. Key discussions include the potential therapeutic strategies targeting macropinocytosis, such as enhancing drug delivery via this pathway, inhibiting macropinocytosis to starve cancer cells, blocking the degradation and recycling of macropinosomes, and inducing methuosis - a form of cell death triggered by excessive macropinocytosis. Targeting macropinocytosis represents a novel and innovative approach that could significantly advance the treatment of cancers that rely on this pathway for survival. Through continuous research and innovation, we look forward to developing more effective and safer anti-cancer therapies that will bring new hope to patients.Abbreviation: AMPK: AMP-activated protein kinase; ASOs: antisense oligonucleotides; CAD: carbamoyl-phosphate synthetase 2, aspartate transcarbamylase, and dihydroorotase; DC: dendritic cell; EGF: epidermal growth factor; EGFR: epidermal growth factor receptor; ERBB2: erb-b2 receptor tyrosine kinase 2; ESCRT: endosomal sorting complex required for transport; GAP: GTPase-activating protein; GEF: guanine nucleotide exchange factor; GRB2: growth factor receptor bound protein 2; LPP: lipopolyplex; MTOR: mechanistic target of rapamycin kinase; MTORC1: mechanistic target of rapamycin kinase complex 1; MTORC2: mechanistic target of rapamycin kinase complex 2; NSCLC: non-small cell lung cancer; PADC: pancreatic ductal adenocarcinoma; PDPK1: 3-phosphoinositide dependent protein kinase 1; PI3K: phosphoinositide 3-kinase; PIK3C3: phosphatidylinositol 3-kinase catalytic subunit type 3; PtdIns(3,4,5)P3: phosphatidylinositol-(3,4,5)-trisphosphate; PtdIns(4,5)P2: phosphatidylinositol-(4,5)-bisphosphate; PTT: photothermal therapies; RAC1: Rac family small GTPase 1; RPS6: ribosomal protein S6; RPS6KB1: ribosomal protein S6 kinase B1; RTKs: receptor tyrosine kinases; SREBF: sterol regulatory element binding transcription factor; TFEB: transcription factor EB; TNBC: triple-negative breast cancer; TSC2: TSC complex subunit 2; ULK1: unc-51 like autophagy activating kinase 1; UPS: ubiquitin-proteasome system.