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We previously demonstrated that monosodium glutamate (MSG) consumption increases trimethylamine (TMA) level in the renal tissue as well as dimethylamine and methylamine levels in urine of rats, suggesting the effects of MSG on humans. To better define the findings, we investigated whether MSG consumption alters serum trimethylamine N-oxide (TMAO) level, and as a consequence, induces kidney injury in the rat model. Adult male Wistar rats (n = 40) were randomized to be fed with a standard diet (control group) or a standard diet with 0.5, 1.5 or 3.0 g% MSG corresponding to 7, 21, or 42 g/day in 60 kg man, respectively in drinking water (MSG-treated groups), or a standard diet with 3.0 g% MSG in drinking water which was withdrawn after 4 weeks (MSG-withdrawal group). Blood and urine samples were collected to analyze the TMAO levels using 1H NMR and markers of kidney injury. Fecal samples were also collected for gut microbiota analysis. We found serum TMAO levels increased and urinary TMAO excretion decreased during MSG consumption, in parallel with the increase of the neutrophil gelatinase-associated lipocalin (NGAL) excretion which subsided with the withdrawal of MSG. The fecal 16 S rRNA analysis during MSG consumption showed gut microbiota changes with a consistent suppression of Akkermansia muciniphila, a mucin producing bacteria, but not of TMA-producing bacteria. In conclusions, our findings suggested that prolonged high dose MSG consumption may cause TMAO accumulation in the blood via reduction of renal excretion associated with acute kidney injury. The mechanisms by which MSG reduced TMAO excretion require further investigation.

Diabetes mellitus (DM) is associated with an increased risk and progression of cholangiocarcinoma (CCA). High glucose underlying the association between DM and CCA by modulating the intracellular signaling has been demonstrated. However, the effects of DM and hyperglycemia on cell cycle machineries and progression of CCA remain elucidated. CCA cells, KKU-213A and KKU-213B were cultured in normal (NG, 5.6 mM) or high glucose (HG, 25 mM) resembling euglycemia and hyperglycemia. Western blotting was used to determine expressions of cell cycle machineries in CCA cells. The expression of cyclin A in CCA tissues from patients with or without hyperglycemia was determined by immunohistochemistry. Pan-cyclin dependent kinases (CDKs) inhibitor and silencing of cyclin A expression were investigated as a possible modality targeting CCA treatment in patients with DM. High glucose induced expression of cell cycle machinery proteins in both CCA cells. Among these, cyclin A was consistently and significantly upregulated. Nuclear cyclin A was significantly increased in tumor tissues from CCA patients with hyperglycemia and was significantly associated with post-operative survival of shorter than 5 mo. Silencing cyclin A expression sensitized CCA cells to pan-CDKs inhibitor, suggesting the combined treatment as an alternative approach for treatment of CCA patients with DM. [ABSTRACT FROM AUTHOR]

Background: The association between diabetes mellitus (DM) and the increased risk and progression of cholangiocarcinoma (CCA) has been reported with unclear underlying mechanisms. Previous studies showed that γ-aminobutyric acid (GABA) B2 receptor (GABBR2) was upregulated in CCA cells cultured in high glucose (HG) conditions. Roles of GABA receptors in CCA progression have also been studied, but their association with DM and hyperglycemia in CCA remains unclarified., Aim: To investigate the effects of hyperglycemia on GABBR2 expression and the potential use of GABBR2 as a CCA therapeutic target., Methods: CCA cells, KKU-055 and KKU-213A, were cultured in Dulbecco Modified Eagle's Medium supplemented with 5.6 mmol/L (normal glucose, NG) or 25 mmol/L (HG) glucose and assigned as NG and HG cells, respectively. GABBR2 expression in NG and HG cells was investigated using real-time quantitative polymerase chain reaction and western blot. Expression and localization of GABBR2 in CCA cells were determined using immunocytofluorescence. GABBR2 expression in tumor tissues from CCA patients with and without DM was studied using immunohistochemistry, and the correlations of GABBR2 with the clinicopathological characteristics of patients were analyzed using univariate analysis. Effects of baclofen, a GABA-B receptor agonist, on CCA cell proliferation and clonogenicity were tested using the MTT and clonogenic assays. Phospho-kinases arrays were used to screen the affected signaling pathways after baclofen treatment, and the candidate signaling molecules were validated using the public transcriptomic data and western blot., Results: GABBR2 expression in CCA cells was induced by HG in a dose- and time-dependent manner. CCA tissues from patients with DM and hyperglycemia also showed a significantly higher GABBR2 expression compared with tumor tissues from those with euglycemia ( P < 0.01). High GABBR2 expression was significantly associated with a poorer non-papillary histological subtype but with smaller sizes of CCA tumors ( P < 0.05). HG cells of both tested CCA cell lines were more sensitive to baclofen treatment. Baclofen significantly suppressed the proliferation and clonogenicity of CCA cells in both NG and HG conditions ( P < 0.05). Phospho-kinase arrays suggested glycogen synthase kinase 3 (GSK3), β-catenin, and the signal transducer and activator of transcription 3 (STAT3) as candidate signaling molecules under the regulation of GABBR2, which were verified in NG and HG cells of the individual CCA cell lines. Cyclin D1 and c-Myc, the common downstream targets of GSK3/β-catenin and STAT3 involving cell proliferation, were accordingly downregulated after baclofen treatment., Conclusion: GABBR2 is upregulated by HG and holds a promising role as a therapeutic target for CCA regardless of the glucose condition., Competing Interests: Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article., (©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.)

Background/aim: Changes in epidermal growth factor receptor (EGFR) are commonly found in cancer progression, signaling a poor outcome in patients. In the present study, we aimed to investigate whether nimotuzumab could be of benefit for cholangiocarcinoma (CCA) treatment., Materials and Methods: The expression of EGFR was explored using immunohistochemical staining in cases divided into groups with low and high expression. The effect of nimotuzumab on CCA cell growth, metastasis and the molecular mechanisms by which nimotuzumab inhibits CCA cell metastasis were evaluated., Results: The expression of EGFR was high in 55% of patients with CCA. This was significantly correlated with a shorter survival of patients. CCA cells treated with nimotuzumab showed inhibited cell growth. Moreover, nimotuzumab inhibited CCA cell metastasis via induction of E-cadherin and suppression of zinc finger protein SNAI1 (SNAIL1), vimentin and matrix metalloproteinase 9 (MMP9) expression., Conclusion: Nimotuzumab appears to inhibit cell metastasis via suppression of the epithelial-mesenchymal transition process. Therefore, nimotuzumab should be considered as a potential therapeutic agent against CCA., (Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Background: Effective treatments for cholangiocarcinoma (CCA) are still lacking. There are promising results of checkpoint inhibitor programmed cell death ligand-1 (PD-L1) activities in early phase trials. This study aimed to investigate the expression of PD-L1 and its relation to possible treatments for CCA. Methods: Formalin-fixed paraffin-embedded tumor samples from 46 patients with cholangiocarcinoma were retrieved. PD-L1 expression was evaluated by immunohistochemistry using anti-PD-L1 antibody, clone 5H1. A PD-L1 positive response on tumor cells was defined as >1% of tumor cell membranes stained. The association between PD-L1, clinico-pathological characteristics was analyzed using Fisher’s exact test, and survival analysis was done with the Cox regression model. Results: Out of 46 samples, 32 (70%) had positive PD-L1 expression in tumor cell membranes. The median level of PD-L1 expression was 1.75% (0-34.7). PD-L1 expression was significantly associated with stage IV disease (OR 3.98, p=0.046) and a high neutrophil/lymphocyte ratio (OR 5.36, p=0.018). PD-L1 positivity was associated with worse overall survival compared with those with a PD-L1 negative tumor but did not reach a level of significance (7.2 vs. 7.9 months, p=0.32). Conclusion: PD-L1 is widely expressed in CCA but was not predictive for overall survival. PD-L1 positivity was (7.2 and 7.9 months, p=0.32). Significantly associated with stage IV disease and a high neutrophil/lymphocyte ratio., (Creative Commons Attribution License)