Role Of Glucose Transporter 1 Research Articles

GLUT1 mediates the release of HMGB1 from airway epithelial cells in mixed granulocytic asthma

Asthma is quite heterogenous and can be categorized as eosinophilic, mixed granulocytic (presence of both eosinophils and neutrophils in the airways) and neutrophilic. Clinically, mixed granulocytic asthma (MGA) often tends to be severe and requires large doses of corticosteroids. High mobility group box 1 (HMGB1) is one of the epithelium-derived alarmins that contributes to type 2 inflammation and asthma. This study was aimed to investigate the role of glucose transporter 1 (GLUT1) in modulation of airway epithelial HMGB1 production in MGA. Induced sputum and bronchial biopsy specimens were obtained from healthy subjects and asthma patients. BALB/c mice, the airway epithelial cell line BEAS-2B, or primary human bronchial epithelial cells (HBECs) were immunized with allergens. Intracellular and extracellular HMGB1 were both detected. The role of GLUT1 was assessed by using a pharmacological antagonist BAY876. MGA patients have a significant higher sputum HMGB1 level than the health and subjects with other inflammatory phenotypes. Nuclear-to-cytoplasmic translocation of HMGB1 was also observed in the bronchial epithelia. Allergen exposure markedly induced GLUT1 expression in murine lungs and cultured epithelial cells. Pharmacological antagonism of GLUT1 with BAY876 dramatically decreased airway hyperresponsiveness, neutrophil and eosinophil accumulation, as well as type 2 inflammation in murine models of MGA. Besides, the allergen-induced up-regulation of HMGB1 was also partly recovered by BAY876, accompanied by inhibited secretion into the airway lumen. In vitro, treatment with BAY876 relieved the allergen-induced over-expression and secretion of HMGB1 in airway epithelia. Taken together, our data indicated that GLUT1 mediates bronchial epithelial HMGB1 release in MGA.

Extracellular vesicle glucose transporter-1 and glycan features in monocyte-endothelial inflammatory interactions

Monocyte-induced endothelial cell inflammation is associated with multiple pathological conditions, and extracellular vesicles (EVs) are essential nanosized components of intercellular communication. EVs derived from endotoxin-stimulated monocytes were previously shown to carry pro-inflammatory proteins and RNAs. The role of glucose transporter-1 (GLUT-1) and glycan features in monocyte-derived EV-induced endothelial cell inflammation remains largely unexplored. This study demonstrates that EVs derived from endotoxin-stimulated monocytes activate inflammatory pathways in endothelial cells, which are partially attributed to GLUT-1. Alterations in glycan features and increased levels of GLUT-1 were observed in EVs derived from endotoxin-stimulated monocytes. Notably, inhibition of EV-associated GLUT-1, through the use of fasentin, suppressed EV-induced inflammatory cytokines in recipient endothelial cells.

EgGLUT1 Is Crucial for the Viability of Echinococcus granulosus sensu stricto Metacestode: A New Therapeutic Target?

Cystic echinococcosis (CE) is a zoonotic parasitic disease caused by infection with the larvae of Echinococcus granulosus sensu lato (s.l.) cluster. It is urgent to identify novel drug targets and develop new drug candidates against CE. Glucose transporter 1 (GLUT1) is mainly responsible for the transmembrane transport of glucose to maintain its constant cellular availability and is a recent research hotspot as a drug target in various diseases. However, the role of GLUT1 in E. granulosus s.l. (EgGLUT1) was unknown. In this study, we cloned a conserved GLUT1 homology gene (named EgGLUT1-ss) from E. granulosus sensu stricto (s.s.) and found EgGLUT1-ss was crucial for glucose uptake and viability by the protoscoleces of E. granulosus s.s. WZB117, a GLUT1 inhibitor, inhibited glucose uptake by E. granulosus s.s. and the viability of the metacestode in vitro. In addition, WZB117 showed significant therapeutic activity in E. granulosus s.s.-infected mice: a 10 mg/kg dose of WZB117 significantly reduced the number and weight of parasite cysts (P < 0.05) as efficiently as the reference drug, albendazole. Our results demonstrate that EgGLUT1-ss is crucial for glucose uptake by the protoscoleces of E. granulosus s.s., and its inhibitor WZB117 has a therapeutic effect on CE.

EgGLUT1 is Crucial for the Viability of &lt;i&gt;Echinococcus granulosus sensu stricto&lt;/i&gt; Metacestode: A New Therapeutic Target?

Background: Cystic echinococcosis (CE) is a zoonotic parasitic disease caused by infection with the larvae of Echinococcus granulosus sensu lato (s.l.) cluster. It is urgent to identify novel drug targets and develop new drug candidates against CE. Glucose transporter 1 (GLUT1) is mainly responsible for the transmembrane transport of glucose and is a valuable drug target. However, the role of GLUT1 in E. granulosus s.l. (EgGLUT1) was unknown. Methods: The EgGLUT1-ss gene was cloned from E. granulosus sensu stricto (s.s.). The function of EgGLUT1-ss was identified by interfereing with EgGLUT1-specific siRNA or GLUT1 inhibitor WZB117 in vitro. The therapeutic effect of WZB117 and its effect on the glucose metabolism of larvae of E. granulosus s.s. in vivo were further validated in murine models. Findings: Knockdown of EgGLUT1 and WZB117 inhibited the glucose uptake and the viability of the larvae of E. granulosus s.s. in vitro (P < 0.01). In addition, WZB117 showed significant therapeutic activity in E. granulosus s.s.-infected mice: a 10 mg/kg dose of WZB117 significantly reduced the number and weight of parasite cysts (P < 0.05) as efficiently as the reference drug, albendazole. Interpretation: Our results demonstrate that EgGLUT1-ss is crucial for glucose uptake by the protoscoleces of E. granulosus s.s., and its inhibitor WZB117 has a therapeutic effect on CE. Funding Information: The National Natural Science Foundation of China (82060373, 81760369 and 81360251); State Key Laboratory of Pathogenesis, Prevention and Treatment of Central Asian High Incidence Diseases Fund (SKL-HIDCA-2020-BC3); Tianshan Cedar Science and Technology Innovation Talents Support Plan of Xinjiang Uygur Autonomous Region (No. 2019XS13). Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: All procedures carried out with animals were approved by the Ethical Committee of the First Affiliated Hospital of Xinjiang Medical University (IACUC-20130425012).

Role of GLUT-1 in the Upregulation of PD-L1 Expression After Radiotherapy and Association of PD-L1 with Favourable Overall Survival in Hypopharyngeal Cancer.

PurposeThe alteration of tumor immunity after radiotherapy (RT) has been widely studied in recent years. However, the mechanism through which RT mediates tumor immunity and the involvement of glycolysis in this mediation in hypopharyngeal cancer remain unclear. This study investigated whether RT regulates programmed cell death ligand 1(PD-L1) partly via glucose transporter 1(GLUT-1) expression and whether PD-L1 expression predicts overall survival (OS) in patients with hypopharyngeal cancer.MethodsThe expression of PD-L1 and Glut-1, and the numbers of CD4+, CD8+ T cells were detected by immunohistochemical analysis on 47 pre-RT and 25 post-RT specimens of hypopharyngeal cancer. Changes in these indicators before and after RT were compared, and their association with the OS of patients was analyzed. Moreover, we used siRNA-GLUT-1 to inhibit GLUT-1 expression and examined whether GLUT-1 was a key factor involved in the mediation of PD-L1 expression by RT in vitro.ResultsIn the multivariate analysis, patients with higher PD-L1 expression (p=0.037), higher CD4+ T cell infiltration (p=0.016) and earlier clinical stage (p=0.019) had favourable OS. The expression of PD-L1, and the CD4+ and CD8+ T cells was markedly increased following RT. PD-L1 expression was correlated with Glut-1 pre-RT (p=0.002), but not after RT (p=0.051). The expression of PD-L1 in FaDu cells was upregulated after RT, especially at 96h after RT in vitro. However, the expression of PD-L1 in siRNA-GLUT-1 FaDu cells was markedly decreased at 96h after RT compared with that measured in FaDu cells.ConclusionPatients with high PD-L1 expression and CD4+ T cell infiltration may have favourable OS in hypopharyngeal cancer. RT may increase PD-L1 expression and alter tumor immunity. The expression of PD-L1 was correlated with Glut-1, and inhibition of GLUT-1 expression may decrease the expression of PD-L1. GLUT-1 may participate in the alteration of tumor immunity after RT.

Differential effect of GLUT1 overexpression on survival and tumor immune microenvironment of human papilloma virus type 16-positive and -negative cervical cancer

Glucose transporter-1 (GLUT1) has been proposed as a prognosticator in various cancers associated with therapeutic resistance and immune evasion; however little data is available on the role of GLUT1 in cervical cancer. Most cervical cancers are caused by human papilloma virus (HPV), but studies on the treatment response and prognosis depending on the HPV subtype, are conflicting. This hypothesis-generating study aims to investigate the prognostic impact of GLUT1 in cervical cancer, in conjunction with HPV subtype. Clinicopathologic factors, along with mRNA expression data were obtained using The Cancer Genome Atlas database. Tumor HPV status and immune cell scores were extracted from previous publications. In total, 298 patients were analyzed. High GLUT1 expression was associated with old age, squamous cell carcinoma, high tumor stage, pelvic lymph node metastases, and low hysterectomy rate. Multivariate survival analysis revealed that high GLUT1 expression (Hazard ratio (HR) 2.57, p = 0.002) and HPV16 subtype (HR 0.56, p = 0.033) were independent prognostic factors for overall survival. In the subgroup analysis, poor prognostic impact of high GLUT1 expression was maintained in HPV16-positive group (p < 0.001), but not in HPV16-negative group (p = 0.495). Decreased immune cell scores of CD8+ T cells, B cells, and Th1 cells by high GLUT1 expression were observed only in HPV16-positive group. In conclusion, these results suggested that GLUT1 expression and HPV16 subtype might have an independent prognostic value in cervical cancer. GLUT1-mediated immunomodulation might be an important cause of treatment failure, especially in HPV16-positive group.

Abstract 4074: The effects of the HIF pathway inhibitor NSC-134754 on glucose metabolism

Abstract The master regulator in hypoxic cell survival and adaptation is the hypoxia-inducible factor-1 (HIF-1) pathway. Altered HIF-1 regulated gene expression drives a tumour towards a more malignant phenotype. HIF-1 is thus a therapeutic target, and small molecule inhibitors such as NSC-134754 are being investigated. Glucose transporter 1 (GLUT-1) is an important downstream target of the HIF-1 pathway, with fundamental roles in intracellular glucose flux and availability. Given the intrinsic role of GLUT-1 in glucose metabolism, the ability of NSC-134754 to evoke a unique metabolic response in vitro and in vivo was investigated. Human PC3LN5 prostate tumour cells were treated with 7.5µM NSC-134754 and incubated in a humidified hypoxic workstation (1.0% O2) for 24h. Western blot analysis demonstrated a reduction in GLUT-1 expression in treated cells compared to controls. GLUT-1 immunocytofluorescence confirmed control cells exhibited extensive membranous and diffuse cytoplasmic expression compared to treated cells. Culture media and cell extracts were collected and metabolites analysed using 1H magnetic resonance spectroscopy (MRS). A significant decrease in glucose consumption (p&amp;lt;0.01) and lactate production (p&amp;lt;0.05) in NSC-134754 treated cells compared to control was determined. No significant differences in intracellular lactate concentration were found. However, treatment significantly increased intracellular glucose by &amp;gt;3 fold compared to control cells (p&amp;lt;0.01). Glutamine/glutamate metabolism was also significantly increased in NSC-134754 treated cells (p&amp;lt;0.05). Mice bearing established (∼1cm diameter) orthotopic PC3LN5 prostate tumours were treated with either 100mg/kg i.p. NSC-134754 (n=4) or vehicle alone (n=5) for 24h. Subsequent semi-quantitative immunohistochemical analyses revealed a significant 28 ± 2% decrease in GLUT-1 membrane expression in the treated tumours compared to controls (p&amp;lt;0.01). These data suggest that NSC-134754 has a profound effect on glucose metabolism in vitro and in vivo. Treatment of PC3LN5 cells for 24h in hypoxia significantly reduced the expression and distribution of GLUT-1, decreased glucose uptake and reduced lactate production. A reduction in glucose transport and lactate production have been shown to be indicators of response to therapy. The increased uptake and metabolism of glutamine/glutamate may reflect compensatory mechanisms for reduced glycolysis in order to sustain cellular bioenergetics. Interestingly, we have also shown that NSC-134754 increased intracellular glucose accumulation. Many glycolytic enzymes are known gene targets of HIF, thus a reduction in their availability (and hence glycolysis) could lead to glucose trapping. To our knowledge, this is a novel finding of a small molecule inhibitor of the HIF pathway. Increased intracellular glucose with decreased glucose uptake has been reported with other therapeutics in vitro. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4074. doi:10.1158/1538-7445.AM2011-4074

The Role of GLUT1 in the Sugar-Induced Dielectric Response of Human Erythrocytes

We propose a key role for the glucose transporter 1 (GLUT1) in mediating the observed changes in the dielectric properties of human erythrocyte membranes as determined by dielectric spectroscopy. Cytochalasin B, a GLUT1 transport inhibitor, abolished the membrane capacitance changes in glucose-exposed red cells. Surprisingly, D-fructose, known to be transported primarily by GLUT5, exerted similar membrane capacitance changes at increasing D-fructose concentrations. In order to evaluate whether the glucose-mediated membrane capacitance changes originated directly from intracellularly bound adenosine triphosphate (ATP) or other components of the glycolysis process, we studied the dielectric responses of swollen erythrocytes with a decreased ATP content and of nucleotide-filled ghosts. Resealed ghosts containing physiological concentrations of ATP yielded the same glucose-dependent capacitance changes as biconcave intact red blood cells, further supporting the finding that ATP is the effector of the glucose-mediated dielectric response where the ATP concentration is also the mediating factor in swollen red blood cells. The results suggest that ATP binding to GLUT1 elicits a membrane capacitance change that increases with the applied concentration gradient of D-glucose. A simplified model of the membrane capacitance alteration with glucose uptake is proposed.