Search Results (59)

Enlicitide (MK-0616) is an oral proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor for the treatment of hypercholesterolemia. We conducted the first systematic review and meta-analysis evaluating the efficacy and safety of enlicitide across randomized controlled trials enrolling adults with hypercholesterolemia or heterozygous familial hypercholesterolemia (HeFH). The primary outcome was the baseline-to-endpoint percentage change in low-density lipoprotein cholesterol (LDL-C); secondary outcomes included apolipoprotein B (ApoB), non-high-density lipoprotein cholesterol (non-HDL-C), lipoprotein(a) [Lp(a)], and safety. Four randomized controlled trials involving 3894 participants were included. Enlicitide achieved a substantial reduction in LDL-C (mean difference [MD]: −55.78 percentage points; 95% confidence interval [CI]: −61.15 to −50.42; p < 0.0001; I² = 99.58%), with sustained efficacy demonstrated in the newly available 52-week Phase 3 CORALreef data. Significant reductions were also observed in ApoB (MD: −47.95 pp; 95% CI: −51.22 to −44.67), non-HDL-C (MD: −49.42 pp; 95% CI: −54.23 to −44.60), and Lp(a) (MD: −22.70 pp; 95% CI: −28.62 to −16.78). The pooled incidence of any adverse event was not statistically significant (event rate: 0.21; p = 0.087), and treatment discontinuation due to adverse events was uncommon (event rate: 0.007). Enlicitide demonstrated substantial lipid-lowering efficacy with an acceptable safety profile. The ongoing CORALreef Outcomes trial will determine whether these lipid improvements translate into reductions in major adverse cardiovascular events. Full article

Small-molecule kinase inhibitors offer a compelling therapeutic strategy for glioblastoma, yet their clinical efficacy remains severely limited by blood–brain barrier penetration and active efflux transporter extrusion. This review evaluates current medicinal chemistry approaches and translational paradigms to overcome these drug delivery and biological constraints. A critical analysis of the literature reveals that direct structural optimization faces a multidimensional balancing act; next-generation design must prioritize macrocyclization, structural rigidification, and bioisosteric capping to lower polar surface area and evade P-glycoprotein and BCRP efflux. Furthermore, carrier-mediated prodrugs targeting the LAT1 transporter provide a viable rescue strategy for highly potent scaffolds. Reviewing recent clinical failures, such as paxalisib and osimertinib, underscores that single-node monotherapies fail due to compensatory pathway hyperactivation and clonal heterogeneity, whereas multi-targeted agents or rational dual-node combinations prevent rapid tumor adaptation. Additionally, combining kinase inhibitors with DNA damage repair inhibitors, immune checkpoint modulation, or MR-guided focused ultrasound could provide powerful synergistic networks. Finally, bridging the translational gap requires complementing conventional serum-cultured cell lines with patient-derived glioma stem cells and orthotopic xenografts to better recapitulate the cellular architecture of the disease. Ultimately, overcoming the therapeutic challenges in glioblastoma demands a fundamental pivot toward rigorous neuro-pharmacological design and multi-lineage network oncology. Full article

Background/Objectives: mRNA display technology has emerged as a powerful platform for discovering macrocyclic peptides against intractable proteins. However, direct screening against the “undruggable” transcription factor MYC using this approach remains largely unexplored. In this study, we aimed to integrate tyrosinase-mediated cyclization with mRNA display to identify novel macrocyclic peptide inhibitors targeting MYC. Methods: We performed mRNA display combined with tyrosinase-mediated cyclization to generate macrocyclic peptides targeting MYC. Antiproliferative activity was assessed in MYC-dependent tumor cells using CCK8 assay. C-terminal fusions with a TAT-derived cell-penetrating peptide were generated to enhance cell membrane permeability. Binding affinities were measured by bio-layer interferometry (BLI). MYC transcriptional activity was evaluated by RNA sequencing (RNA-seq) analysis of canonical MYC target genes. Results: The identified macrocyclic peptides exhibited potent antiproliferative activity against MYC-dependent tumor cells, with half-maximal inhibitory concentration (IC₅₀) values in the micromolar range. Fusion with the TAT peptide improved antiproliferative potency, yielding IC₅₀ values of 1–3 μM in MYC-dependent cell lines. BLI assays confirmed dose-dependent binding of the peptides to MYC, with dissociation constants (Kd) in the micromolar range. Furthermore, RNA-seq analysis revealed significant downregulation of canonical MYC target genes upon treatment with the TAT-fusion macrocyclic peptide, indicating specific suppression of MYC transcriptional activity. Conclusions: This work establishes the feasibility of using mRNA display to target the “undruggable” protein MYC and identifies a panel of macrocyclic peptides as promising lead candidates for further optimization toward targeted therapies for MYC-driven cancers. Full article

Janus kinase 2 (JAK2) occupies a central position in cytokine signaling and plays essential roles in hematopoiesis, immune regulation, and cancer. Although recent advances in structural biology, cryo-EM, receptor modeling, and biophysical analysis have substantially expanded current views of JAK2 function, key mechanistic questions remain regarding how receptor geometry, JH2-mediated autoinhibition, and disease-associated mutations are structurally integrated. In this review, we discuss the multidomain organization of JAK2 and examine how the FERM–SH2 module, the pseudokinase domain (JH2), and the catalytic kinase domain (JH1) cooperate to govern receptor specificity, allosteric control, and cytokine-induced activation. We further analyze how pathogenic mutations rewire this regulatory system by weakening autoinhibitory contacts, altering linker-mediated communication, or stabilizing active dimeric conformations. Finally, we assess current and emerging therapeutic strategies, from ATP-competitive inhibitors to macrocyclic and JH2-selective allosteric modulators, with emphasis on how structural insight can guide next-generation drug design. These advances support a more integrated view of JAK2 regulation and define new opportunities for selective therapeutic intervention. Full article

Background/Objectives: Fragment-based approaches in the field of drug discovery and design have been widely developed and employed in both academia and industry. We present here an innovative in silico fragment-based drug design approach aimed at designing new inhibitors in the ATP-binding site of protein kinases. Methods: This tool, named Frags2Drugs (F2D), relies on a three-dimensional fragment library obtained from co-crystallized ligands. This library is stored in a graph-oriented database containing the required information to link fragments together. F2D builds every possible molecule that fits into the given cavity on a minute scale. Molecules are then filtered to keep those presenting the best predicted affinity. Several specific molecular filters can be applied, including protein kinase inhibitor-like filters. Results: We validated our method by reconstructing existing co-crystallized ligands and known kinase inhibitors. In this study, we provide several examples of its use to retrieve known or design new type I, type I1/2, type II, and macrocyclic inhibitors on several protein kinases. Conclusions: We have developed an in silico fragment-based ligand design tool able to identify novel kinase inhibitors by growing any scaffolds positioned in the ATP-binding site.. Full article

Macrocyclic drugs are promising for targeting undruggable proteins, including those in cancer. Our prior work identified BE-43547A₂ (BE) as a selective inhibitor of pancreatic cancer stem cells in PANC-1 cultures, but its high lipophilicity limits clinical application. To address this, we designed derivatives retaining BE’s backbone while modifying tail groups to improve its properties. A concise total synthesis enabled a versatile late-stage intermediate (compound 17), serving as a platform for efficient diversification of BE analogs via modular click chemistry. This approach introduced a central triazole ring connected by flexible alkyl spacers. Key properties, including lipophilicity, solubility, and Caco-2 permeability, were experimentally determined. These derivatives exhibited reduced lipophilicity and improved solubility but unexpectedly lost cellular activity. Direct target engagement studies using MicroScale Thermophoresis (MST) revealed compound-dependent deactivation mechanisms: certain derivatives retained binding to eEF1A1 with only modestly reduced affinity (e.g., compound 29), while others showed no detectable binding (e.g., compound 31). Microsecond-scale molecular dynamics simulations and free-energy calculations showed that, for derivatives retaining target affinity, tail modifications disrupted the delicate balance of drug–membrane and drug–solvent interactions, resulting in substantially higher transmembrane free-energy penalties (>5 kcal/mol) compared to active compounds (<2 kcal/mol). These insights emphasize the need to simultaneously preserve both target engagement and optimal permeability when modifying side chains in cell-permeable macrocyclic peptides, positioning compound 17 as a robust scaffold for future lead optimization. This work furnishes a blueprint for balancing drug-like properties with therapeutic potency in macrocyclic therapeutics. Full article

Viral fusion proteins are indispensable mediators of viral entry that orchestrate the fusion of viral and host membranes, making them primary targets for antiviral interventions. Class I fusion proteins, displayed on the surface of enveloped viruses (such as HIV-1, RSV, SARS-CoV-2, Nipah, influenza, and Ebola viruses), share conserved structural features, including the fusion peptide or loop and heptad repeat regions. These elements are essential for the formation of the post-fusion six-helix bundle during membrane fusion. Peptide inhibitors that mimic heptad repeat motifs have consequently emerged as an effective strategy for blocking the fusion process. This review summarizes design strategies for such inhibitors and highlights how sequence and structural insights have enabled their optimization via α-helical stabilization, hydrocarbon stapling, lactam bridges, lipid conjugation, macrocyclization, and multivalency. Using representative examples across major viral systems, this review illustrates how these strategies have led to the development of potent, stable, and even broad-spectrum antiviral peptides. This review provides insights to guide the rational design of next-generation peptide-based fusion inhibitors targeting viral membrane fusion. Full article

Antimicrobial resistance remains a critical global health challenge, and was intensified by the COVID-19 pandemic. To address this growing threat, novel antibacterial agents targeting unconventional mechanisms are urgently needed. One promising strategy involves inhibiting bacterial riboswitches—RNA elements that regulate gene expression. Unlike most riboswitches that respond to small-molecule metabolites, the T-box riboswitch uniquely binds non-aminoacylated tRNA and is predominantly found in Gram-positive bacteria, making it an attractive target due to its conserved sequences and regulatory role over essential genes. This study explored oxazolidinone- and triazole-based compounds as potential inhibitors of the T-box riboswitch. Prior investigations into tricyclic oxazolidinones revealed an allosteric modulator that effectively inhibited T-box riboswitch transcriptional readthrough in vitro, though it showed limited disruption of the isolated tRNA–antiterminator complex. To enhance RNA-binding affinity and stereoselectivity, a macrocyclic oxazolidinone scaffold was designed, incorporating a strategic substituent to expand the interaction footprint. A synthetically viable candidate was identified, and computational docking studies suggested that one of the designed compounds may interfere with tRNA-induced transcription by forming π–π stacking interactions with G5 in the antiterminator region. These findings support the potential of targeting the T-box riboswitch with structurally optimized small molecules as a novel antibacterial strategy. Full article

Antimicrobial resistance has emerged as one of the most critical public health challenges of the 21st century, threatening to undermine the foundations of modern medicine. In 2019, bacterial infections accounted for 13.6% of all global deaths, with more than 7.7 million fatalities directly attributable to 33 bacterial pathogens, most prominently Staphylococcus aureus, Streptococcus pneumoniae, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Resistance mechanisms are multifactorial, encompassing enzymatic degradation, target modification, efflux pump overexpression, reduced membrane permeability, and biofilm formation, often in combination, leading to multidrug-resistant, extensively drug-resistant, and pandrug-resistant phenotypes. Alarmingly, projections estimate that by 2050 AMR could result in over 10 million deaths annually. This comprehensive review synthesizes global epidemiological data, insights into bacterial resistance mechanisms, and emerging therapeutic solutions, including novel antibiotics such as lasso peptides and macrocyclic peptides (e.g., zosurabalpin), naturally derived compounds (e.g., corallopyronin, clovibactin, chlorotonil A), and targeted inhibitors (e.g., Debio 1453 for Neisseria gonorrhoeae). Addressing the AMR crisis requires coordinated international efforts, accelerated drug discovery, and the integration of innovative non-antibiotic approaches to preserve the efficacy of existing therapies and ensure preparedness against future bacterial threats. Full article

Signal-dependent transport into and out of the nucleus mediated by members of the importin (IMP) superfamily is crucial for eukaryotic function, with inhibitors targeting IMPα being of key interest as anti-infectious agents, including against the apicomplexan Plasmodium species and Toxoplasma gondii, causative agents of malaria and toxoplasmosis, respectively. We recently showed that the FDA-approved macrocyclic lactone ivermectin, as well as several other different small molecule inhibitors, can specifically bind to and inhibit P. falciparum and T. gondii IMPα functions, as well as limit parasite growth. Here we focus on the FDA-approved antiparasitic moxidectin, a structural analogue of ivermectin, for its IMPα-targeting and anti-apicomplexan properties for the first time. We use circular dichroism and intrinsic tryptophan fluorescence measurements to show that moxidectin can bind directly to apicomplexan IMPαs, thereby inhibiting their key binding functions at low μM concentrations, as well as possessing anti-parasitic activity against P. falciparum in culture. The results imply a class effect in terms of IMPα’s ability to be targeted by macrocyclic lactone compounds. Importantly, in the face of rising global emergence of resistance to approved anti-parasitic agents, the findings highlight the potential of moxidectin and possibly other macrocyclic lactone compounds as antimalarial agents. Full article

The insulin-regulated aminopeptidase (IRAP; oxytocinase) is part of the M1 aminopeptidase family and is highly expressed in many tissues, including the neocortex and hippocampus of the brain. IRAP is involved in various physiological functions and has been identified as a receptor for the endogenous hexapeptide Angiotensin IV (Ang IV). The binding of Ang IV inhibits the enzymatic activity of IRAP and has been proven to enhance learning and memory in animal models. The macrocyclic compound 9 (C9) is a potent synthetic IRAP inhibitor developed from the previously reported inhibitor HA08. In this study, we have examined compound C9 and its effects on cognitive markers drebrin, microtubule-associated protein 2 (MAP2), and glial fibrillary acidic protein (GFAP) in primary hippocampal and cortical cultures. Cells from Sprague Dawley rats were cultured for 14 days before treatment with C9 for 4 consecutive days. The cells were analysed for protein expression of drebrin, MAP2, GFAP, glucose transporter type 4 (GLUT4), vesicular glutamate transporter 1 (vGluT1), and synapsin I using immunocytochemistry. The gene expression of related proteins was determined using qPCR, and viability assays were performed to evaluate toxicity. The results showed that protein expression of drebrin and MAP2 was increased, and the corresponding mRNA levels were decreased after treatment with C9 in the hippocampal cultures. The ratio of MAP2-positive neurons and GFAP-positive astrocytes was altered and there were no toxic effects observed. In conclusion, the IRAP inhibitor compound C9 enhances the expression of the pro-cognitive markers drebrin and MAP2, which further confirms IRAP as a relevant pharmaceutical target and C9 as a promising candidate for further investigation. Full article

Furin, a serine protease enzyme located in the Golgi apparatus of animal cells, plays a crucial role in cleaving precursor proteins into their mature, active forms. It is ubiquitously expressed across various tissues, including the brain, lungs, gastrointestinal tract, liver, pancreas, and reproductive organs. Since its discovery in 1990, furin has been recognized as a significant therapeutic target, leading to the active development of furin inhibitors for potential use in antiviral, antibacterial, anticancer, and other therapeutic applications. This review provides a comprehensive overview of the progress in the development and characterization of furin inhibitors, encompassing peptides, linear and macrocyclic peptidomimetics, and non-peptide compounds, highlighting their potential in the treatment of both infectious and non-infectious diseases. Full article

Tropomyosin receptor kinases (Trks) are transmembrane receptor tyrosine kinases named TrkA, TrkB, and TrkC and encoded by the NTRK1, NTRK2, and NTRK3 genes, respectively. These kinases have attracted significant attention and represent a promising therapeutic target for solid tumor treatment due to their vital role in cellular signaling pathways. First-generation TRK inhibitors, i.e., Larotrectinib sulfate and Entrectinib, received clinical approval in 2018 and 2019, respectively. However, the use of these inhibitors was significantly limited because of the development of resistance due to mutations. Fortunately, the second-generation Trk inhibitor Repotrectinib (TPX-0005) was approved by the FDA in November 2023, while Selitrectinib (Loxo-195) has provided an effective solution to this issue. Another macrocycle-based analog, along with many other TRK inhibitors, is currently in clinical trials. Two of the three marketed drugs for NTRK fusion cancers feature a pyrazolo[1,5-a] pyrimidine nucleus, prompting medicinal chemists to develop numerous novel pyrazolopyrimidine-based molecules to enhance clinical applications. This article focuses on a comprehensive review of chronological synthetic developments and the structure–activity relationships (SAR) of pyrazolo[1,5-a]pyrimidine derivatives as Trk inhibitors. This article will also provide comprehensive knowledge and future directions to the researchers working in the field of medicinal chemistry by facilitating the structural modification of pyrazolo [1,5-a]pyrimidine derivatives to synthesize more effective novel chemotherapeutics as TRK inhibitors. Full article

Amyloid fibroproliferation leads to organ damage and is associated with a number of neurodegenerative diseases affecting populations worldwide. There are several ways to protect against fibril formation, including inhibition. A variety of organic compounds based on molecular recognition of amino acids within the protein have been proposed for the design of such inhibitors. However, the role of macrocyclic compounds, i.e., thiacalix[4]arenes, in inhibiting fibrillation is still almost unknown. In the present work, the use of water-soluble thiacalix[4]arene derivatives for the inhibition of hen egg-white lysozyme (HEWL) amyloid fibrillation is proposed for the first time. The binding of HEWL by the synthesized thiacalix[4]arenes (logKa = 5.05–5.13, 1:1 stoichiometry) leads to the formation of stable supramolecular systems capable of stabilizing the protein structure and protecting against fibrillation by 29–45%. The macrocycle conformation has little effect on protein binding strength, and the native HEWL secondary structure does not change via interaction. The synthesized compounds are non-toxic to the A549 cell line in the range of 0.5–250 µg/mL. The results obtained may be useful for further investigation of the anti-amyloidogenic role of thiacalix[4]arenes, and also open up future prospects for the creation of new ways to prevent neurodegenerative diseases. Full article

Tuberculosis is one of the most common infectious diseases in the world, caused by Mycobacterium tuberculosis. The outbreak of multiple drug-resistant tuberculosis has become a major challenge to prevent this disease worldwide. ClpC1 is a Clp ATPase protein of Mycobacterium tuberculosis, functioning as a chaperon when combined with the Clp complex. ClpC1 has emerged as a new target to discover anti-tuberculosis drugs. This study aimed to explore the ClpC1 inhibitors from actinomycetes, which have been known to provide abundant sources of antibiotics. Two cyclic peptides, including nocardamin (1), halolitoralin A (3), and a lactone pleurone (2), were isolated from the culture of Streptomyces aureus (VTCC43181). The structures of these compounds were determined based on the detailed analysis of their spectral data and comparison with references. This is the first time these compounds have been isolated from S. aureus. Compounds 1–3 were evaluated for their affection of ATPase activity of the recombinant ClpC1 protein. Of these compounds, halolitoralin A (1), a macrocyclic peptide, was effective for the ATPase hydrolysis of the ClpC1 protein. Full article