Chronic hepatitis B virus (HBV) infection is a serious public health burden, and current treatments fail to achieve satisfactory cure rates. RG7834 is a novel therapeutic agent with a differentiated mechanism of action (MOA) compared to current standard treatments. However, its Phase I clinical trial was terminated due to neurotoxicity issues. Furthermore, the pharmacokinetic performances of RG7834 are unsatisfactory, leaving significant room for improvement. This article reports some attempts and efforts based on the RG7834 molecule, including enhancing antiviral activity, improving pharmacokinetic performance in various genera. Ultimately, we obtained a preferred molecule 42 that, compared with RG7834, exhibited stronger in-vitro antiviral activity and significantly better pharmacokinetic performance in dogs, and cynomolgus monkeys. 42 demonstrated strong in vivo anti-HBV activity in an AAV/HBV mouse model, warranting further investigation.

A series of novel trans-stilbene-phytophenol/phenolic acid conjugates linked through a triazole moiety were synthesized via Knoevenagel condensation and copper-catalyzed azide-alkyne cycloaddition. Among the 24 synthesized compounds 23-46, compound 24 emerged as the most potent candidate, exhibiting strong cytotoxicity against MCF-7 and MDA-MB-231 breast cancer cells, while showing substantially lower toxicity toward normal NKE cells. Compound 24 markedly suppressed clonogenic survival and induced apoptosis, as demonstrated by Annexin V/PI staining, enhanced caspase-3 activity, and nuclear condensation and fragmentation. Cell-cycle analysis revealed pronounced G2/M arrest with increased sub-G0 accumulation. Mechanistically, compound 24 significantly increased intracellular and mitochondrial reactive oxygen species (ROS), accompanied by substantial mitochondrial membrane depolarization, suggesting ROS-mediated mitochondrial dysfunction as an important contributor to apoptosis. Molecular docking demonstrated favorable binding of compound 24 within the colchicine-binding pocket of β-tubulin supporting stable protein-ligand interactions. Furthermore, in silico ADMET profiling indicated favorable drug-like and predicted safety characteristics. Collectively, compound 24 represents a promising tubulin-targeting anticancer lead that suppresses breast cancer cell survival through coordinated G2/M arrest, oxidative stress, mitochondrial dysfunctions, and caspase-dependent apoptosis, warranting further preclinical investigation.

Neutral sphingomyelinase 2 (nSMase2) catalyzes the hydrolysis of sphingomyelin to generate ceramide and phosphocholine and has emerged as a potential therapeutic target for diseases associated with dysregulated ceramide signaling. Phenyl (R)-(1-(3-(3,4-dimethoxyphenyl)-2,6-dimethylimidazo[1,2-b]pyridazin-8-yl)pyrrolidin-3-yl)carbamate (PDDC), a submicromolar nSMase2 inhibitor based on an imidazo[1,2-b]pyridazin-8-amine scaffold, has been widely used to investigate the pharmacological effects of nSMase2 inhibition. In the course of our efforts to expand the structural diversity of nSMase2 inhibitors, we identified the imidazo[1,2-b]pyridazin-3-amine scaffold as a novel chemotype for nSMase2 inhibition. Systematic structure-activity relationship studies led to several submicromolar nSMase2 inhibitors, although the series generally exhibited high clearance in liver microsomes. These studies establish the imidazo[1,2-b]pyridazin-3-amine scaffold as a promising framework for the development of potent nSMase2 inhibitors while highlighting metabolic stability as a key remaining challenge for this chemotype.

Vincamine, a monoterpene indole alkaloid from Vinca minor, possesses a wide range of pharmacologically important biological activities including anticancer properties as well as antidiabetic and anti-Alzheimer's effects. Starting from tryptamine and various functionalized 5-chlorovaleraldehydes, seven vincamine derivatives containing a tetrahydro-β-carboline- (THBC)-scaffold were synthesized via Pictet-Spengler reaction. Selected products were further converted to their corresponding N-Boc functionalized counterparts. In addition to the THBC-compounds two sets of oxidized byproducts, open-chain formamides and spirocyclic molecules, were isolated from the Pictet-Spengler reaction. The latter showed a very distinct three-dimensional curved structure, which could lead to potential applications not only as lead compounds in drug development but also as ligands for metal ion coordination and thus as potential catalysts in synthesis. In this work, selected synthesized compounds were tested for biological activities in various assays representing the abovementioned properties of vincamine to gain insight in structure-activity-relationships. We could determine cytotoxic effects of vincamine derivatives in the low double digit micromolar range with the lowest IC50 value being 16 μM for 1-cyclohexyl-1,2,3,4,6,7,12,12b-octahydroindolo[2,3-a]quinolizine. Furthermore, promising results were obtained for BChE inhibition, again with IC50 values in the low micromolar range for most of the compounds. The most interesting result for α-glucosidase inhibition was achieved by N-Boc-1-methyl-1,2,3,4,6,7,12,12b-octahydroindolo[2,3-a]quinolizine with an IC50 value of 17 μM.

The cannabinoid receptor type 2 (CB2) is a promising therapeutic target for neuroinflammatory diseases, whereas conventional orthosteric agonists suffer from poor selectivity and metabolic instability. Allosteric modulation, particularly by peptide-based modulators, offers a new strategy to overcome these limitations, yet the molecular mechanisms underlying CB2 allosteric regulation and efficient discovery tools remain lacking. In this study, we computationally investigated the role of the CB2 extracellular putative site J as a predicted binding site for peptide modulators. Using molecular docking and dynamics simulations, we obtained computational insights into the dynamic hydrogen-bonding networks through which the known peptide allosteric modulators Pepcan-12 and osteogenic growth peptide (OGP) are predicted to selectively bind to putative site J in the active-state receptor, with key predicted interacting residues including Ser180, Asn188, Thr272 and Met22. Based on this computational model, we established a flexible docking screening framework targeting putative site J and identified five promising sequences from 56 peptides, among which Pep-5 exhibited the best performance. In vitro functional assays demonstrated that Pep-5 concentration-dependently inhibited cAMP accumulation (EC50 = 6.0 μM) in a manner dependent on CB2 expression. Furthermore, Pep-5 increased the cAMP inhibitory effect of the orthosteric agonist WIN55,212-2, an observation consistent with potential positive allosteric modulation. Through an integrated strategy of "computational mechanistic exploration-rational design-functional validation", this study proposes the putative site J as a potential allosteric site for peptide-based modulation of CB2 and provides candidate peptide Pep-5, offering a new theoretical basis for developing CB2-targeted allosteric drugs.

Targeting the epidermal growth factor receptor (EGFR) remains a proven strategy for the treatment of lung adenocarcinoma; however, acquired drug resistance and suboptimal long-term efficacy of the currently available EGFR inhibitors spurred the pursuit of new EGFR-targeted molecules. Hence, a series of pyridine-cored derivatives was rationally designed by strategically integrating pharmacophoric features of Gefitinib. Subsequently, the molecules were synthesised via promising synthetic approaches (Pd-catalyzed CN coupling, nucleophilic substitution reaction), and the characterized compounds (3-5 and 7a-h) were screened at the cellular level using the lung cancer cells (A549) via MTT assay. Consequently, the evaluated compounds were identified as promising leads at the cellular level. Specifically, molecule 5 exhibited potent antiproliferative activity against the A549 cells, with an IC50 value of 8.90 ± 1.6 μM, which was comparable to that of Gefitinib (IC50 = 9.22 ± 1.153 μM). Importantly, molecule 5 exhibited reduced cytotoxicity over the non-cancerous mouse fibroblast cells (L929). Moreover, mechanistic studies of molecule 5 demonstrated enhanced clonogenic survival, modulated intracellular ROS levels, substantially enhanced apoptotic cell populations, and modulation of EGFR protein expression as determined by ELISA. Notably, the combination of molecule 5 with gefitinib revealed the apparent IC50 value of 7.13 ± 0.53 μM under the specific experimental condition. On the other hand, molecular docking studies predicted the favourable binding modes with the EGFR binding sites, with predicted favourable binding affinities ranging from -7.4 to -10.3 kcal/mol. In addition, MD simulation and DFT calculations provide supportive insights into the predicted stability of the ligand-receptor complex and the electronic properties of the synthesised molecules. Collectively, molecule 5 represents as promising pyridine-based scaffold for further investigation as an anti-NSCLC lead, through additional structural modification, and further studies are required to establish its precise molecular mechanism.

Selective inhibition of protein tyrosine phosphatase 1B (PTP1B), a well-established target in metabolic and oncological signaling pathways, is limited by its 74% active-site identity with the closely related phosphatase TCPTP. Repurposing the clinical-stage Bcl-xL BH3 mimetic A-1331852, we identify it as a potent PTP1B inhibitor demonstrating a selectivity margin of at least 50-fold over TCPTP (IC50 = 4.0 μM vs >200 μM). Kinetic analysis reveals uncompetitive inhibition consistent with recognition of a substrate-induced binding site. Docking and 500 ns molecular dynamics simulations (MD) of full-length PTP1B support a putative multisite model that primarily engages the catalytic domain, with secondary stabilizing contacts at the intrinsically disordered C-terminus (ΔGbind = -42.95 kcal/mol). Comparative MD of Bcl-xL reveals a structurally distinct binding footprint, indicating that dual inhibition is driven by target-specific recognition rather than the engagement of a shared structural motif. In silico modeling of a predicted PTP1B-Bcl-xL complex suggests a coupled disorder-to-order interface bridging the PTP1B C-terminus and the Bcl-xL BH3-binding groove. Together, these results highlight A-1331852 as a promising starting point for developing PTP1B inhibitors designed to exploit transient, substrate-induced binding states.

Axially chiral benzochalcogenophene derivatives bearing sulfur and selenium atoms in their fused cyclic rings were synthesized. Subsequently, their anti-proliferative activity against pancreatic ductal adenocarcinoma and acute myelogenous leukemia cells was evaluated. Optical resolution of these compounds was achieved, and their absolute configurations were determined using X-ray crystallography and CD spectroscopy. Anti-proliferative activity revealed a marked dependence on both axial chirality and the identity of the chalcogen atoms. The benzothiophene derivative (S)-2 potently inhibited the proliferation of all tested cancer cell lines, whereas its enantiomer, (R)-2, displayed weaker activity. In addition, (S)-2 showed stronger anti-proliferative activity than the corresponding selenium analog (S)-1. These results demonstrate that both axial chirality and the nature of the chalcogen atoms affect biological activity. Mechanistic studies demonstrated that (S)-2 induces DNA damage, G2/M-phase arrest, mitotic accumulation, and caspase-dependent apoptosis. These results suggest that (S)-2 is a promising seed compound for the development of novel anticancer agents.

Tumor hypoxia, a characteristic feature of solid tumors that induces chemoresistance, enables the rational design of tumor-selective prodrugs. Brusatol (BST), a natural quassinoid with broad-spectrum antitumor effects, faces obstacles to clinical translation due to high systemic toxicity and insufficient tumor selectivity, and hypoxia-activated prodrug approaches for BST have not yet been investigated. In this study, 12 hypoxia-responsive BST derivatives were constructed using 2-nitroimidazole as the hypoxia-sensitive group; linkers with varied lengths and chemical bonds were introduced to establish structure-activity relationships. Serial screening of drug release behavior, antitumor potency and biosafety identified ZJ-1 as the optimal candidate. ZJ-1 rapidly and fully releases BST under hypoxia, effectively inhibits hypoxic tumor cell proliferation, and displays markedly lower toxicity toward normal hepatocytes and human peripheral blood mononuclear cells than parent BST. In MGC-803 gastric cancer xenografts, high-dose ZJ-1 achieved a tumor growth inhibition (TGI) rate of 74.37%, superior to oxaliplatin and unmodified BST. The median lethal dose (LD50) of ZJ-1 in mice was 2.7 times that of BST, demonstrating improved in vivo tolerability. Collectively, ZJ-1 holds promise for broadening the therapeutic window. This work describes the first hypoxia-activated BST prodrug with potent in vivo efficacy and improved safety, providing a targeted delivery strategy and a promising lead agent for gastric cancer treatment.

Alzheimer's disease (AD) is a progressive and multifactorial neurodegenerative disorder characterized by cholinergic dysfunction, amyloid-β (Aβ) aggregation, tau hyperphosphorylation, oxidative stress, mitochondrial impairment, metal dyshomeostasis, and chronic neuroinflammation, collectively leading to irreversible cognitive decline and neuronal degeneration. Despite decades of intensive research, currently approved therapeutic agents, including cholinesterase inhibitors (ChEI) and NMDA receptor antagonists, provide only symptomatic relief and do not substantially alter disease progression. Among the clinically available ChEI, rivastigmine (RIV) has attracted considerable attention owing to its dual inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), pseudo-irreversible mode of action, and established clinical efficacy in AD management. In recent years, RIV has emerged as a highly promising pharmacophoric scaffold for the development of multifunctional hybrid molecules designed according to the multi-target-directed ligand (MTDL) strategy to modulate multiple pathological pathways involved in AD simultaneously. This review comprehensively summarizes and critically analyzes advances reported from 2020 to 2026 in the design, synthesis, biological evaluation, and therapeutic potential of RIV-based hybrid molecules and scaffold modifications for AD treatment. The review places particular emphasis on the rational hybridization of RIV with diverse bioactive pharmacophores, including tryptamine, coumarin, flavonoids, melatonin, tacrine, ferulic acid, cannabidiol, benzimidazole, piperidine, aryloxacetic acid, and antioxidant motifs, to generate multifunctional agents with enhanced pharmacological profiles. The reviewed hybrids demonstrated remarkable multifunctional properties, including potent inhibition of AChE and BChE, suppression of Aβ aggregation, antioxidant and metal-chelating activities, anti-inflammatory effects, modulation of monoamine oxidases, neuroprotection, mitochondrial stabilization, and improved blood-brain barrier permeability. Several derivatives exhibited significantly greater potency and broader neuroprotective profiles than RIV itself, highlighting the therapeutic value of molecular hybridization approaches in AD drug discovery.

Histone deacetylases (HDACs) are epigenetic enzymes linked to several biological functions and diseases. Class I HDACs (HDAC1-3) share high protein sequence and active site similarity. Hydroxamate-based inhibitors, while highly potent, are non-selective with poor pharmacokinetic profile, prompting exploration of alternative zinc-binding groups. The study applied criteria-guided identification of HDAC3 inhibitors with alternative zinc-binding groups following structure-based virtual screening, with a prioritisation of HDAC3-specific binding interactions and bidentate/monodentate interaction with the zinc ion. Metal-focused chemical libraries were screened virtually followed by biochemical assessment of inhibitory activity of the hit compounds and cell cytotoxicity evaluation. Compound a displayed sub-micromolar HDAC3 potency (IC50 = 0.99 μM) but limited selectivity for HDAC3, whereas compound b showed reduced potency (IC50 = 15 μM) yet possessed HDAC3 preference. Molecular docking suggests that the zinc-binding group of the compounds form bidentate/monodentate metal coordination with the zinc ion and hydrogen bond interaction with Asp170. Compound a showed a high cytotoxicity IC50 value of 34.5 μM on neuroblastoma cells (IMR-32 cells) and IC50 on liver (HepG2) cells was >100 μM, while HDAC3 inhibition occurred at sub-micromolar concentrations. Compound b showed HDAC3 inhibitory preference without inducing cytotoxicity on liver and neuroblastoma cells.

Breast cancer is a primary contributor to cancer-related mortality, particularly among females worldwide, and the number of new cases is rising annually. For a very long period, breast carcinoma was treated with chemotherapy; however, its efficacy is often limited by drug resistance and severe side effects. Accordingly, the development of safer and more effective bioactive compounds capable of halting breast neoplastic cells' proliferation and metastasis remains a critical priority. In the present study, a series of novel dihydropyrimidinone (DHPM) imines (5-14) was synthesized and characterized via different spectroscopic techniques, including NMR, mass spectroscopy, FT-IR, and elemental analysis. The binding interactions of DHPMs with the AKT protein, along with their pharmacokinetic profiles, were evaluated through in silico analysis. Subsequent in vitro studies demonstrated that compound 10 exhibited substantial toxicity on MCF-7 cells with minimal toxicity towards normal fibroblasts. Flow cytometry revealed G0/G1 cell cycle arrest and apoptosis induction by compound 10 in MCF-7 cells. This was accompanied by the downregulation of RAS, PI3K, AKT, and GSK-3β protein levels, along with upregulation of p21 and Bax and suppression of c-Myc and Bcl-2 gene expression. Moreover, compound 10 suppressed colony formation and the wound healing assay confirmed its ability to constrain cell migration. Collectively, these findings indicate that compound 10 exerts efficient antineoplastic impact associated with the downregulation of the RAS/PI3K/AKT/GSK-3β pathway proteins.

JAK3 is a non-receptor tyrosine kinase that plays an important role in immune signaling pathways. It has long been indicated as a potential target for autoimmune diseases. In this work, a set of 28 novel JAK3 inhibitors were designed around a thieno[3,2-d]pyrimidine core, with aromatic moieties at the 2-position, and a range of alkyl linkers connected to electrophillic groups at the 4-position. Structure-based design has been employed in an attempt to maximize activity through direct reaction of the inhibitor electrophile and Cys909 residue located within the JAK3 active site. We identified the acrylamide containing compound 42 as a potent inhibitor of JAK3, with an IC50 of 6.2 nM and selectivity of 23.4-fold over the related JAK2 enzyme. This compares to 1.4 nM and 53.1-fold, respectively, for the 1st generation JAK3 inhibitor Tofacitinib. 42 also demonstrated good selectivity against 10 diverse kinases at a screening concentration of 1 μM, a low logD7.4 of 1.51 and good phosphate buffer solubility (1030.8 μg/ml). Computational analysis was undertaken to help rationalize the SAR in the form of molecular dynamics simulations and quantum chemical cluster calculations of electrophile-nucleophile reactivity.

Fms-like tyrosine kinase 3 (FLT3), a member of the type III receptor tyrosine kinase family, is identified as a promising drug target for treatment of acute myeloid leukemia (AML). Here, we designed and synthesized a series of new FLT3 PROTAC degraders by incorporating rigid linkers between gilteritinib and CRBN ligand. Among them, ZLC6-49 and ZLC10-3 were identified as the most potent degraders with DC50 values of 0.74 nM and 1.28 nM, and Dmax values of 85% and 88%, respectively. Mechanistic studies demonstrated that ZLC6-49 and ZLC10-3 induce FLT3 degradation in a cereblon- and proteasome-dependent manner. Furthermore, ZLC6-49 and ZLC10-3 potently inhibit FLT3 downstream signaling, suppress cell proliferation, induce apoptosis and G0/G1-phase arrest in MV4-11 cells.

Multidrug-resistant (MDR) Gram-negative bacteria pose significant therapeutic challenges due to their protective outer membranes and evolving resistance mechanisms. Exploiting bacterial iron uptake pathways via siderophore-antibiotic conjugates offers a promising strategy to enhance antibiotic efficacy. Here we synthesized siderophore-aztreonam, and siderophore-daptomycin conjugates and compared their activity to that of cefiderocol against select Gram-negative pathogens, including MDR Acinetobacter baumannii and Pseudomonas aeruginosa. Our in vitro studies demonstrated that siderophore conjugates exhibit comparable or superior antimicrobial activity to, with daptomycin conjugates notably retaining efficacy over extended periods. These findings suggest that conjugation with iron chelators that closely mimic natural siderophores can improve antibiotic delivery and activity, providing complementary options to existing therapies for multidrug-resistant Gram-negative infections.