明治薬科大学

Advanced glycation end-products (AGEs), having multiple structures, are formed at the sites where the carbonyl groups of the reducing sugars bind to the free amino groups of the proteins through the Maillard reaction. The accumulation of AGEs, which are generated when carbonyl compounds produced in the process of glucose metabolism react with proteins, is involved in various carbonyl stress-related diseases. Meanwhile, guanidine compounds, represented by aminoguanidine, have possibilities as a scavenger that inhibits AGE formation by directly reacting with carbonyl compounds. We here focused on existing drugs with a guanidine-like structure and estimated the reactivity of nine drugs, including aminoguanidine, with methylglyoxal (MGO), a glucose metabolite, to assess their potential application to carbonyl stress-induced diseases. Considering the results of the two screening methods, we concentrated on streptomycin, which exhibited stable scavenging activity, and evaluated its inhibitory effect on the MGO-induced AGE formation in proteins in vitro. Furthermore, the effects of streptomycin on carbonyl protein accumulation in the cells and the MGO-induced cytotoxicity were investigated to elucidate the cytoprotective potential against glycation. The results revealed that streptomycin added to the culture medium with MGO suppressed the MGO-induced carbonylation of intracellular proteins and exerted a protective effect by alleviating the toxicity of MGO in a study using human-derived neuroblastoma SH-SY5Y. These findings suggest that the clinically available streptomycin has a potential to be utilized for carbonyl stress-related diseases as a repurposing drug.

PURPOSE:Amikacin (AMK) is a widely used therapeutic drug monitoring (TDM)-recommended treatment for nontuberculous mycobacterial pulmonary disease (NTM-PD). However, its optimal dosage and TDM target remain unclear. In this study, we aimed to clarify the relationship between AMK exposure, ototoxicity, and efficacy. METHODS:Patients with NTM-PD treated with AMK at Fukujuji Hospital were retrospectively included in this study. The correlation between AMK exposure, measured by peak and trough levels and the area under the concentration-time curve (AUC), ototoxicity, and culture conversion was analyzed using the Mann-Whitney U test and Cox regression analysis. A population pharmacokinetic/pharmacodynamic (PPK/PD) model was developed to predict ototoxicity using TDM measurements. RESULTS:A total of 185 patients were enrolled. The median AMK dose and observation period were 500 (interquartile range [IQR], 500-600) mg/day and 45.8 (IQR, 31.3-76.5) months, respectively. Ototoxicity and culture conversion were observed in 39% and 54% of the enrolled patients, respectively, after initiating AMK. The median time to the development of ototoxicity was 69 (IQR; 43-97) days. Neither ototoxicity nor culture conversion was associated with pharmacokinetic parameter of AMK exposure, including its minimum inhibitory concentration. However, the cumulative AUC was significantly higher in patients who developed ototoxicity (P < 0.001) than in those without ototoxicity. The developed PPK/PD model enabled calculation of cumulative AUC from TDM data and prediction of ototoxicity onset. CONCLUSION:Cumulative AMK exposure was associated with ototoxicity, and our findings allow prediction of ototoxicity onset using AMK TDM data.

Phospholipase A2 group VI (PLA2G6, also called iPLA2β) has been implicated in male fertility, neuronal disorders, and metabolic diseases. However, its therapeutic effects on metabolic disorders remain elusive. We investigated the effects of PLA2G6 suppression on glucose and lipid metabolism. Systemic inhibition of PLA2G6 in high-fat diet-fed mice reduced hepatic lipid droplet size without altering the levels of serum triglycerides and fasting blood glucose. Suppression of liver-specific Pla2g6 utilizing the short-hairpin RNA knockdown technique using an adenovirus vector (Ad-shPLA2G6) altered phospholipid and fatty acid metabolites and suppressed hepatic lipid accumulation, serum triglyceride, fasting glucose, and insulin levels. Additionally, Ad-shPLA2G6 treatment downregulated lipid biosynthesis-related genes but upregulated peroxisomal fatty acid oxidation-related genes. These findings indicate that targeting hepatic Pla2g6 modulates phospholipid and fatty acid metabolites and improves glucose and lipid metabolism, suggesting Pla2g6 as a potential therapeutic target in metabolic disorders, including type 2 diabetes mellitus and metabolic dysfunction-associated steatotic liver disease.

Lung cancer remains the leading cause of cancer-related mortality worldwide, largely due to therapeutic resistance and tumor recurrence. In non-small cell lung cancer (NSCLC), cancer stem cells (CSCs) have emerged as key contributors to tumor persistence and progression. However, accelerated CSC-targeted drug discovery is limited by the lack of scalable and quantitative screening systems capable of capturing stemness-associated phenotypes. Conventional two-dimensional (2D) assays often fail to reflect the architectural and molecular complexity of CSC-enriched tumor populations. Here, we report the establishment of a luciferase-based three-dimensional (3D) NSCLC spheroid platform integrating CSC-like enrichment with a high-throughput quantitative readout. The luminescent signal strongly correlated with spheroid burden and viable cell content. Compared with 2D monolayers, 3D NSCLC spheroids exhibited elevated expression of pluripotency-associated factors, including OCT4, NANOG, and SOX2, and CSC-associated markers, namely CD44, ALDH1A1, and ABCG2, supporting the enrichment of CSC-like subpopulations. As a proof-of-concept, screening of renieramycin T right-half derivatives identified DH_18 as a lead compound in the established 3D NSCLC spheroid model, exhibiting greater potency than DH_19, accompanied by increased apoptosis and reduced CSC-associated proteins in follow-up experimental validation. Integrated network pharmacology incorporating enrichment and protein-protein interaction analyses further mapped DH_18-NSCLC targets to lung CSC-associated networks and pathways related to stemness and aggressive tumor phenotypes, reinforcing the biological relevance of the 3D screening context. Collectively, these findings present a quantitative and scalable 3D NSCLC spheroid platform suitable for CSC-targeted drug screening and nominate DH_18 as a candidate compound with potential activity against stemness-linked molecular networks.