Background: Glutamate and glutamine are the most abundant amino acids in the blood and play a crucial role in cell survival in the nervous system. Various transporters found in cell and mitochondrial membranes, such as the solute carriers (SLCs) superfamily, are responsible for maintaining the balance of glutamate and glutamine in the synaptic cleft and within cells. This balance affects the metabolism of glutamate and glutamine as non‐essential amino acids. Aims: This review aims to provide an overview of the transporters and enzymes associated with glutamate and glutamine in neuronal cells. Discussion: We delve into the function of glutamate and glutamine in the nervous system by discussing the transporters involved in the glutamate‐glutamine cycle and the key enzymes responsible for their mutual conversion. Additionally, we highlight the role of glutamate and glutamine as carbon and nitrogen donors, as well as their significance as precursors for the synthesis of reduced glutathione (GSH). Conclusion: Glutamate and glutamine play a crucial role in the brain due to their special effects. It is essential to focus on understanding glutamate and glutamine metabolism to comprehend the physiological behavior of nerve cells and to treat nervous system disorders and cancer.
8 March 2019 in Journal of Experimental & Clinical Cancer Research
Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children with poor survival. New treatment approaches are urgently needed to improve treatment efficacy in RMS patients. DMAMCL is a novel agent from Asteraceae family that has been tested in phase I clinical trials in adult glioma in Australia. Five RMS cell lines (RD, RH18, RH28, RH30 and RH41) were used. The in vitro anti-tumor effect of DMAMCL, alone or in combination with VCR or Epirubicin, was studied using MTS assay or IncuCyte-Zoom cell confluency assay, and further validated by xenograft-mouse model in vivo. Changes in caspase-3/7 activity, cell-cycle progression and generation of ROS after DMAMCL treatment were investigated. Bim mRNA expression was measured by RT-qPCR, and protein expressions of Bim and phosphorylated-NF-κB(p65) by Western blotting. Small interfering RNAs (siRNA) of Bim were used to study the role of Bim in DMAMCL-induced cell death. In vitro, DMAMCL treatment induced a dose-dependent increase in cell death that could be blocked by pan-caspase-inhibitor-Z-VAD-fmk in five RMS cell lines. The percent of cells in SubG1 phase and activities of caspase-3/7 increased after DMAMCL treatment; The combination of DMAMCL with VCR or Epirubicin significantly increased cell death compared to each reagent alone. In vivo, DMAMCL(75 mg/kg or 100 mg/kg) inhibited tumor growth and prolonged survival of mice bearing xenograft RMS tumors (RD, RH18, RH30, RH41). Compared to treatment with DMAMCL or VCR, a combination of two reagents caused significant inhibition of tumor growth (RD, RH41), even after treatment termination. The expression of Bim increased at protein level after DMAMCL treatment both in vitro and in vivo. The expression of p-NF-κB(p65) had a transient increase and the generation of ROS increased after DMAMCL treatment in vitro. Transfection of Bim siRNA into RMS cells blocked the DMAMCL-induced increase of Bim and partially attenuated the DMAMCL-induced cell death. DMAMCL had an anti-tumor growth effect in vitro and in vivo that potentially mediated by Bim, NF-κB pathway and ROS. A combination of DMAMCL with chemotherapeutic drugs significantly increased the treatment efficacy. Our study supports further clinical evaluation of DMAMCL in combination with conventional chemotherapy.
Backgroud. Multiple studies have reported blood inflammatory markers as reliable prognostic factors in various malignant tumors. However, their prognostic effect in patients with bone sarcomas has not been determined. We performed this meta-analysis to evaluate the prognostic value of pretreated blood inflammatory markers in patients with bone sarcoma. Method. We conducted a detailed literature search in Medline and Embase databases and collected relevant publications written in English before April 2020. Overall survival (OS) and disease-free survival (DFS) were the primary and secondary outcomes, respectively. Basic features of patients, hazard ratios (HRs), and 95% confidence intervals (CI) were retrieved to assess the correlation between pretreated blood inflammatory markers and patients with bone sarcoma. This meta-analysis used Stata 12.0. Results. A total of 10 studies containing 1845 cases were included for analysis. Nine of them evaluated the neutrophil lymphocyte ratio (NLR), 7 the platelet lymphocyte ratio (PLR), and 4 the lymphocyte monocyte ratio (LMR). Pooled results revealed that higher pretreatment NLR was associated with poorer OS ( , 95% CI: 1.29–2.41, and ) and DFS ( , 95% CI: 1.09–2.88, and ). In contrast, a lower LMR was related to worse OS ( , 95% CI: 0.57–0.92, and ), but not DFS ( , 95% CI: 0.41–1.11, and ). Combined results did not show a significant predictive effect of PLR on the clinical outcomes of patients with bone sarcoma ( , 95% CI: 0.99–1.75, and ; DFS: , 95% CI: 0.87–1.44, ). Conclusion. NLR and LMR might be promising predictive biomarkers for patients with bone sarcoma and could be used to stratify patients and provide personalized therapeutic strategies.
Aims: Neuroblastoma (NB) is the most common extracranial solid tumor in children, with a 5‐year survival rate of <50% in high‐risk patients. MYCN amplification is an important factor that influences the survival rate of high‐risk patients. Our results indicated MYCN regulates the expression of SESN1. Therefore, this study aimed to investigate the role and mechanisms of SESN1 in NB.Methods: siRNAs or overexpression plasmids were used to change MYCN, SESN1, or MyD88's expression. The role of SESN1 in NB cell proliferation, migration, and invasion was elucidated. Xenograft mice models were built to evaluate SESN1's effect in vivo. The correlation between SESN1 expression and clinicopathological data of patients with NB was analyzed. RNA‐Seq was done to explore SESN1's downstream targets.Results: SESN1 was regulated by MYCN in NB cells. Knockdown SESN1 promoted NB cell proliferation, cell migration, and cell invasion, and overexpressing SESN1 had opposite functions. Knockdown SESN1 promoted tumor growth and shortened tumor‐bearing mice survival time. Low expression of SESN1 had a positive correlation with poor prognosis in patients with NB. RNA‐Seq showed that Toll‐like receptor (TLR) signaling pathway, and PD‐L1 expression and PD‐1 checkpoint pathway in cancer were potential downstream targets of SESN1. Knockdown MyD88 or TLRs inhibitor HCQ reversed the effect of knockdown SESN1 in NB cells. High expression of SESN1 was significantly associated with a higher immune score and indicated an active immune microenvironment for patients with NB.Conclusions: SESN1 functions as a new tumor suppressor gene via TLR signaling pathway in NB.
Corrigendum: Downregulation of ATXN3 enhances the sensitivity to AKT inhibitors (Perifosine or MK-2206), but decreases the sensitivity to chemotherapeutic drugs (etoposide or cisplatin) in neuroblastoma cells