Journal of Enzyme Inhibition and Medicinal Chemistry最新文献

Inosine 5'-monophosphate dehydrogenase (IMPDH) is a promising antimicrobial target due to its central role in guanine nucleotide biosynthesis. Accurate and reliable kinetic measurements are essential for evaluating inhibitors. However, the enzyme's complex reaction mechanism and substrate cooperativity complicate analysis, leading to inconsistent reports on IMPDH reaction kinetics in key pathogenic mycobacteria. Here, we present an in-depth biochemical analysis of mycobacterial IMPDH, revealing pH-dependent cooperativity mediated by IMP-driven interactions between catalytic domains within the tetramer. This mechanism may result in paradoxical activation by IMP-competitive inhibitors under specific substrate conditions. We further show that such effects may influence apparent inhibition by the natural allosteric regulators GTP and ppGpp. Based on these findings, we outline practical recommendations for designing kinetic experiments that reflect physiologic conditions with the aim of more accurately evaluating IMPDH inhibitors for drug discovery.

Aberrant activation of YAP-TEAD4 drives tumorigenesis, progression, and chemoresistance. Disrupting their interaction serves as an alternative anticancer strategy, with peptides better adapting to the large, flat interaction interface. In this study, the peptides 1-4 were screened from the peptide database via pharmacophore modelling, molecular docking, and interaction analysis. Subsequently, affinity experiments showed that among the peptides 1-4, peptide-4 possessed the lowest K_d values (K_d = 5.08 ± 0.42 nM) measured by MST and exhibited the binding affinity for TEAD4. MD simulations further demonstrated that peptide-4 stably bound to the TEAD4. MTT assays showed that peptide-4 suppressed AML-193 cell viability with an IC₅₀ of 0.65 ± 0.04 μM. RT-qPCR assays demonstrated that Peptide-4 significantly downregulated the mRNA expression levels of CTGF and CYR61. In conclusion, the data demonstrated that the peptide-4 may serve as a promising candidate to disrupt the YAP-TEAD4 interaction and enhance biological activity in AML-related cellular models.

We recently observed a significantly higher level of renalase (RNLS) in aldosterone-producing adenomas (APAs) than in the APA-adjacent adrenal glands (AAGs). RNLS is a flavin adenine dinucleotide-dependent monoamine oxidase. In this study, we investi-gated the effect of RNLS on adrenocortical aldosterone production. RNLS upregulated aldosterone production in adrenocortical cells without interfering with cell proliferation. RNLS (4 μg/ml) increased the mRNA expression of HSD3B2 (p = 0.0128) and CYP21A2 (p = 0.0013) and markedly stimulated that of CYP11B2 (p < 0.0001). Regarding the mechanism, we excluded classical calcium signalling stimulation and found that RNLS activated cAMP/PKA signalling and then upregulated the transcription factor NR4A2 and the phosphorylation of ATF/CREB family members. Immunofluorescence and immuno-precipitation results revealed that RNLS bound to the receptor PMCA4b on the cell membrane, with siPMCA4b preventing RNLS from exerting pro-aldosterone production (p = 0.0157, RNLS+siPMCA4b vs RNLS+siNC). RNLS facilitates aldosterone secretion and may emerge as a hazardous molecule for promoting aldosterone-mediated pathological conditions.

In this work, 17 derivatives were synthesised by combining halogenated and non-halogenated cinnamoyl scaffolds with menthol and tested against a panel of Gram-positive and Gram-negative bacteria. Among the synthesised derivatives, MF1 and MCl2 demonstrated enhanced therapeutic potential. MF1 showed the most potent antimicrobial activity (MIC values ranging from 8 to 64 mg/L against E. faecium), representing a significant improvement over menthol, with a five-fold reduction in MIC₅₀. Additionally, MF1 effectively reduced biofilm biomass production by 50% in S. aureus and by 20% in P. aeruginosa at sub-MIC concentrations. MCl2 reduced biomass by up to 40% in A. baumannii at the lowest subMIC concentrations tested (0.06 x MIC). Moreover, MCl2 showed potential as a wound healing agent promoting fibroblast-mediated repair within just 24 h. Notably, both compounds exhibited no cytotoxic effects. Molecular docking and molecular dynamics simulations confirmed strong binding affinity and high stability of MF1 and MCl2 with the target protein.

A series of oxadiazole-based dual inhibitors targeting GSK3 and HDAC6 were rationally designed by integrating key pharmacophores into a single molecule. Among these derivatives, 4-(((5-(benzo[d][1, 3]dioxol-5-yl)-1,3,4-oxadiazol-2-yl)thio)methyl)-N-hydroxybenzamide (15i) was identified as the most potent compound with IC₅₀ of 5.50, 69 nM and 88 nM against HDAC6, GSK3α and GSK3β, respectively. 15i also exhibited potent cytotoxicity against the AGS cancer cell line, with IC₅₀ values in the submicromolar range. Molecular docking simulation confirmed that 15i fitted well into the active sites of both HDAC6 and GSK3β. These findings establish compound 15i as a promising candidate for further evaluation.

In studying the roles of reactive oxygen species (ROS) in various biological processes, the availability of appropriate cell culture models is critical. Addition of H₂O₂ to cells is commonly used to simulate oxidative stress. In doing so, generation of highly reactive oxygen species (hROS) in cell culture is used as an indication of successful model creation. The validity of such a model is predicated on the assumption that hROS formation is the result of cellular biochemical processes and not from the medium. However, we observed a significant level of hROS in various culture media alone upon H₂O₂ addition, raising questions about the validity of such models and suggesting a "Trojan Horse" role for such media in compromising the data. Given the wide-spread use of the said method, we urge caution in analysing information gained from such models in redox mechanistic studies.

Fluorescently labelled small molecule probes (fluorescent probes) play an important role in cell imaging and are often used in combination with light-affinity probes to determine the subcellular localisation of target proteins. To investigate the target proteins of 18β-glycyrrhetinic acid (18β-GA), which regulates the macrophage inflammatory response, we designed and synthesised three types of fluorescent probes. We analysed its structure-activity relationship by evaluating the biological activity and screening for fluorescent probes with high activity. Our results showed that modifying C-3 hydroxyl and C-30 carboxyl groups enhanced the anti-inflammatory activity of 18β-GA, and found that two preferred probes had similar effects on LPS-induced, inflammation-related factor release (IL-1β, TNF-α, IL-6, HDAC8, P-STAT3, and SOCS3) to those of 18β-GA. Fluorescence signals of the preferred probes Ia and IIc were observed in the cytoplasm. The above results indicated that the anti-inflammatory site of 18β-GA may be located in proteins in the cytoplasm, which would provide useful information for research on the anti-inflammatory targets of 18β-GA.

Poly(ADP-ribose) polymerase (PARP) inhibitors constitute a significant class of targeted anticancer therapies that leverage the principle of synthetic lethality in tumours deficient in homologous recombination (HR) repair. Although these agents have shown clinical efficacy in treating HR-deficient tumours, their wider application has been limited by challenges including the emergence of drug resistance, dependency on HR deficiency phenotypes, and related hematological toxicity. To mitigate these limitations, dual-target PARP inhibitors have emerged as a promising therapeutic strategy, simultaneously modulating PARP and synergistic pathways within a single molecular entity. This approach effectively circumvents the pharmacokinetic complexities and cumulative toxicity associated with multi-drug regimens, while simultaneously enhancing therapeutic efficacy through complementary mechanisms. This review highlights recent progress in PARP-based dual inhibitors, focusing on target selection, structure-activity relationships, synergistic antitumor mechanisms, and future research directions. It combines preclinical and clinical insights to guide the development of next-generation PARP dual-target inhibitors with improved efficacy and safety.

The liver is essential for metabolism and detoxification and can regenerate effectively. However, severe injuries or major surgeries can hinder this ability, leading to liver insufficiency or failure. Recent research has identified mitogen-activated protein kinase kinase 4 (MKK4) as a key negative regulator of liver regeneration, making it a promising therapeutic target. Inhibiting MKK4 reduces apoptosis and enhances liver regeneration, spurring interest in small molecule inhibitors of MKK4 for therapeutic strategies to promote liver recovery. This review systematically elucidates the structural characteristics and biological functions of MKK4, alongside its regulatory mechanisms in liver regeneration. It emphasises recent advancements in the research of small molecule inhibitors targeting MKK4 and offers a thorough and comprehensive analysis of the structure-activity relationships of the reported MKK4 inhibitors. The objective is to provide theoretical insights and research directions for the development of efficient and specific MKK4 inhibitors.

HIF2α is aberrantly upregulated in some renal cell carcinomas due to VHL mutations, supporting HIF2α inhibition as a compelling therapeutic approach for such cases. Therefore, the six compounds (designated as Compounds 1-6) were screened from the Maybridge database based on the constructed pharmacophore model and molecular docking. Subsequently, the docking models of Compounds 1-6 with HIF2α were analysed. Affinity assays revealed that both Compound-4 and Compound-5 exhibited robust affinity towards human recombinant HIF2α. MD simulations displayed that Compound-4 and Compound-5 stably bound to the active pocket of HIF2α. Cell experiments demonstrated that Compound-4 effectively inhibited the growth of the 786-O human renal cell carcinomas line (IC₅₀ = 1.35 ± 0.06 μM). This study demonstrates that Compound-4 may serve as a potential candidate compound for renal cell carcinomas therapy.