Bioorganic Chemistry最新文献

A series of twenty novel imidazopyridine-benzoxazole hybrid (Imp1-20) derivatives was designed and synthesized, and their antiproliferative activities were evaluated against MDA-MB-231 breast and DLD-1 colorectal cancer cell lines. Among them, Imp-18 and Imp-20 emerged as the most potent candidates, with low micromolar to nanomolar IC₅₀ values and significant reductions in cancer cell adhesion and colony formation. Flow cytometry analyses demonstrated that both compounds induced apoptosis and promoted cell-cycle arrest, reflected by Sub-G1 accumulation and perturbations in G1/G0 and G2/M phases. Immunofluorescence imaging of β-tubulin confirmed that Imp-18 and Imp-20 compromise microtubule integrity, with Imp-18 displaying stronger tubulin-disrupting activity than nocodazole. The resulting microtubule destabilization was consistent with mitotic arrest and activation of apoptotic signaling pathways. Additionally, both compounds markedly inhibited cancer cell migration, indicating an ability to impair metastatic behavior. Overall, these findings identify Imp-18 and Imp-20 as promising microtubule-targeting agents with robust anticancer potential, providing a strong basis for further mechanistic studies and structural optimization within the framework of medicinal and bioorganic chemistry.

Edwardsiella tarda is an intracellular pathogen capable of surviving within macrophages, evading immune surveillance, and inducing apoptosis and necrosis, leading to systemic infections in both aquatic animals and humans. Unlike traditional ochratoxins-mycotoxins known for nephrotoxic, hepatotoxic, and immunotoxic effects-we identified a novel hydroxy-containing ochratoxin derivative, ochratoxin E (1), along with three known ochratoxins (2-4), from the marine fungus Aspergillus sp. NBU1109. The structure and absolute configuration of compound 1 were elucidated using HRESIMS, NMR, ECD calculations, and single-crystal X-ray diffraction. Crucially, compound 1 showed no cytotoxicity in human LX-2 or murine RAW 264.7 cells, in contrast to the toxic effects of compounds 2-4. Functionally, compound 1 enhanced macrophage phagocytosis and bactericidal activity against E. tarda, and suppressed apoptosis and necrosis. Mechanistically, drug-affinity responsive target stability (DARTS), molecular docking, and cellular thermal shift assays (CETSA) confirmed that compound 1 directly binds AIFM1. This interaction blocked the AIFM1-RIP3 association, reduced RIP3 nuclear translocation, and inhibited apoptotic-necroptotic signaling. These results delineate a unique, non-toxic ochratoxin derivative that targets the AIFM1/RIP3 axis to bolster macrophage defense, highlighting its promise as a lead compound for anti-E. tarda therapy development.

Cancer stem cells (CSCs) or tumor-initiating cells represent a drug-resistant subpopulation with self-renewal and metastatic capacity. There are no CSC-specific drugs that have been developed so far. Plectin is a cytoskeletal protein that uniquely translocates to the outer cell membrane (surface translocated plectin - STP) in CSCs and contributes to proliferation, migration, invasion, and metastasis. We previously identified an STP targeted peptoid-PCS2, and the dimeric version PCS2D1.2, which selectively binds to non-small cell lung cancer (NSCLC) derived CSCs, displayed both in vitro and in vivo anti-cancer activity. The current study reports the identification of the minimum pharmacophore and the optimization of PCS2D1.2 to obtain an improved version of trimeric peptoid PCS2T3.9. Various multimerization strategies with linker optimization and truncation of non-important residues resulted in PCS2T3.9, which demonstrated 21-fold improvement of the cytotoxic activity against high STP expressing H358 non-small cell lung cancer (NSCLC) cells, while showing minimum effects on low STP expressing H460 cells. PCS2T3.9 had no cytotoxic activity on normal bronchial epithelial HBEC-3KT cells. Furthermore, PCS2T3.9 effectively suppressed colony formation and cell migration-hallmarks of CSC phenotype-specifically in H358 cells but not in H460 cells. These findings strongly correlate high STP expression with cancer stemness characteristics and confirm the selective targeting of PCS2T3.9 on CSCs, producing anti-cancer activity. The highly specific and selective cytotoxic effects of PCS2T3.9 on STP-enriched CSCs offer a significant therapeutic advantage by potentially minimizing off-target effects on normal tissues, establishing this peptoid as a promising candidate for CSC-specific NSCLC therapy development.

Titanocene complexes are promising antineoplastic agents limited by poor aqueous stability. This study introduces a series of cytotoxic prodrugs designed to overcome inherent drawbacks of titanocene and its derivatives. We demonstrate that by attaching long aliphatic chains and a tridentate dipic-type ligand, we can improve their solubility and stability, while adjusting their affinity for albumin. The presence of the long aliphatic chain and the reduced polarity of the titanocene headgroup favor self-assembly in PBS with an apparent aggregation onset near ∼10^-5 M (onset concentration, OC). However, when albumin protein is present in solution the self-assembly process is strongly affected due to formation of protein-complex adducts and the OC increases almost 10-fold for the derivative with 14 carbon atoms chain and even higher for the 18 carbon atoms ones. Molecular docking studies indicate that the primary interaction site in BSA is IB, away from the classical fatty acid or drug interaction sites. UV-visible absorption and NMR spectroscopies demonstrate that the formed adducts are dynamic and undergo additional conformation changes. Finally, as proof-of-concept, we demonstrate the structure-activity relationship between cytotoxicity and the length of the aliphatic chain. An increase in the length of the aliphatic chain leads to enhanced cellular internalization of titanium, which correlates with greater cytotoxic activity. These results provide the basis for the development of stable and cytotoxic titanocene-based prodrugs with improved albumin protein affinity.

The global rise of multidrug-resistant (MDR) pathogens invalidates conventional antibiotics, while natural antimicrobial peptides (AMPs) lack proteolytic stability and precise targeting. This study reports a protease-resistant symmetric (RRYY)₂P(YYRR)₂ scaffold (Y = isoleucine/tryptophan) with alternating cationic-hydrophobic repeats, a central proline hinge, and palindromic topology for dual bacterial membrane-genomic DNA targeting. Two derived peptides, RI8 and RW8, were characterized: RI8 showed broad-spectrum activity against MDR pathogens (MIC: 2-16 μg/mL), high therapeutic index (39.4), negligible hemolysis (<1% at 128 μg/mL), and retained efficacy in physiological salts/serum. RW8 exhibited robust protease resistance (1-2× MIC vs trypsin/chymotrypsin, 0.5× MIC vs 8 mg/mL pepsin for 8 h) and Staphylococcus aureus biofilm inhibition (71.4% at 2× MIC) via downregulating icaD/icaB/sarA. Mechanistically, both peptides disrupted bacterial membranes and bound genomic DNA; molecular dynamics simulations confirmed membrane insertion via helix-to-coil transition. In murine models, RI8/RW8 accelerated MDR-infected wound healing and reduced bacterial burdens by 2-5 logs; for S. aureus pneumonia, they outperformed levofloxacin (3-5 vs 2 logs bacterial load reduction) and restored immune function (improved thymus index, reduced pro-inflammatory cytokines). This work establishes a symmetric peptide scaffold as a versatile AMP platform, with RI8 showing promise for systemic MDR infections and RW8 for localized biofilm-associated infections. Overall, these findings highlight a rational design strategy that may help address key translational limitations of conventional antibiotics.

Homoisoflavonoids, a unique subclass of flavonoids with an additional C3 carbon, exhibit diverse pharmacological activities. Herein, we report the first total synthesis and stereochemical elucidation of liriopeins A-D, naturally occurring homoisoflavonoids bearing methyl substituents on their A ring. Using regioselective aromatic halogenation and late-stage Suzuki-Miyaura methylation, we achieved straightforward access to the four compounds and resolved their enantiomers by chiral-phase HPLC. The absolute configuration of the natural liriopeins was unambiguously determined to be the (R)-form, representing the first structural confirmation of these natural products. In contrast, the synthetic (S)-enantiomer of liriopein C exhibited the markedly stronger cytotoxicity against non-small-cell lung cancer cells, with sub-micromolar IC₅₀ values. Mechanistic studies revealed the induction of apoptosis, as confirmed by Annexin V/7-AAD staining and poly (ADP-ribose) polymerase cleavage. In addition to its direct cytotoxicity, liriopein C treatment enhanced macrophage-mediated tumor cell clearance in vivo, significantly increasing the uptake of cancer cells by F4/80⁺CD11b⁺ peritoneal macrophages. These findings demonstrate that liriopeins possess dual antitumor and immunomodulatory activity, highlighting their potential as natural product-inspired leads for cancer immunochemotherapy.

Ischemic stroke arises from vascular occlusion that triggers oxygen-glucose deprivation in neurons and glial cells, subsequently leading to metabolic collapse, excitotoxicity, and ultimately neuronal dysfunction and cell death. Ferroptosis, a form of regulated cell death characterized by iron accumulation and excess reactive oxygen species (ROS), is a key process in the pathological progression of ischemic stroke. Yet, current approaches for the investigation and treatment of ferroptosis in ischemia are limited by sensitivity of detection, spatial resolution to examine affected cells and tissues, and capacity for real-time monitoring. To address such challenges, we have developed a novel mitochondria-targeted fluorescent probe, XZTU-red-GSH, based on an excited-state intramolecular proton transfer (ESIPT) mechanism, such that the probe exhibits prominent, near-infrared emission at 720 nm and a large stokes shift of 315 nm, markedly enhancing fluorescence sensitivity and signal-to-noise ratio. Structurally, XZTU-red-GSH incorporates an N-methylpyridinium moiety for mitochondria targeting via electrostatic interactions, a 2,4-dinitrobenzenesulfonyl group as a selective response unit for glutathione (GSH), and a triethylene glycol monomethyl ether fragment to optimize the lipophilicity-hydrophilicity balance for optimizing blood-brain barrier permeability. In both oxygen-glucose deprivation/reperfusion (OGD/R) cellular models and middle cerebral artery occlusion (MCAO) animal models, the probe enabled in situ visualization of dynamic mitochondrial glutathione (mGSH) depletion during ferroptosis. Furthermore, our experiments with this probe demonstrated that the ferroptosis inhibitor Ferrostatin-1 (Fer-1) mitigates neuronal injury by preserving mGSH homeostasis. Taken together, our results indicate that XZTU-red-GSH is a novel tool to explore the dynamic features ferroptosis and ischemic stroke.

Apigeninidin (APN) is a flavonoid belonging to the 3-deoxyanthocyanidin family, exhibiting diverse biological activities and representing a potential natural antitumor compound. However, the poor lipophilicity and cell membrane permeability of APN limit its bioavailability and antitumor activity. To overcome these limitations, we designed a site-specific propynylation strategy and synthesized two derivatives, APN-A and APN-B, investigating how targeted modification alters APN's antitumor activity. Comparative analysis of the physicochemical properties and bioactivities of these compounds revealed that APN-A exhibited significantly enhanced cell membrane permeability and increased anticancer activity against cervical cancer cells compared to the parent compound APN. In vitro experiments further demonstrated that APN-A can dramatically reduce the viability of cervical cancer cells, inhibited cell proliferation and migration, and synergistically potentiate the antitumor efficacy of 5-fluorouracil (5-FU). In addition, chemical proteomics enrichment analyses indicated that APN-A shows its antitumor effects primarily by targeting and inhibiting processes such as DNA replication and protein transcription-translation in cancer cells via targeting proteins such as PARP-1, EIF3J, and TCEA1. These findings provide a methodological reference and mechanistic insight for the propynyl modification of APN, and highlight its potential applications in the food industry and drug development.

Fatty acid synthase (FASN), which is highly expressed in multiple cancers, contributes critically to cancer cell survival, proliferation, and metastasis, rendering it a promising target for therapeutic intervention. To develop novel and efficient FASN inhibitors, a series of lipophilic amide fragments were introduced into the natural inhibitor mangiferin (MGF) to synthesize new MGF derivatives. Among these derivatives, compound 4 demonstrated notable antiproliferative activity against human hepatocellular carcinoma cell lines with high FASN expression. In particular, 4 exhibited the most potent activity against Hep-G2 cells (IC₅₀ = 0.47 ± 0.06 μM), demonstrating 185-fold greater potency than MGF (IC₅₀ = 87.24 ± 2.06 μM). The capability to bind to FASN and inhibit its activity was significantly stronger than that of MGF. Further investigations revealed that 4 was involved in blocking the activation of PI3K/AKT pathway, thereby inducing reactive oxygen species production and promoting cancer cells apoptosis. Moreover, 4 exhibited a high selectivity index toward Hep-G2 cells (SI = 260.00) and inhibited the migration and invasion of Hep-G2 cells. These findings may serve as a valuable reference for the development of novel FASN inhibitors exhibiting potent anti-hepatocellular carcinoma activity.