Glucose transporter-1 expression in squamous cell carcinoma of the tongue

Study of expression of GLUT-1 in oral potentially malignant disorders and oral squamous cell carcinoma: An immuno-histochemical analysis

Background

Glucose is the chief source of energy for cells, and glucose transporter 1 (GLUT-1) is one of the most common glucose transporters in humans. Tumour cells are known to express hypoxia-related protein, and these may allow tumour cells to survive under a sustained hypoxic environment. Surviving cells develop a more aggressive phenotype, which results in poor prognosis.

Aims and Objectives

Expression and comparison of GLUT-1 in normal tissues, potentially malignant disorders (PMDs), and oral squamous cell carcinoma (OSCC) and comparison of expression in different grades of OSCC.

Material and Methods

A total of 57 cases (10 normal, 17 PMD, and 30 cases of OSCC) were stained immuno-histochemically with GLUT-1. The expression was scored as 0, 1, 2, 3, and 4 for negative, mild, moderate, severe, and intense staining, respectively.

Results

GLUT-1 expression was detected in all grades of OSCC. A significant correlation was found on comparing normal and OSCC, normal and PMDs, and PMD and OSCC. The expression of GLUT-1 was significant when compared with different histopathological grades of OSCC.

Conclusions

Expression of GLUT-1 increased from normal to PMDs to increasing grades of OSCC and hence can be used as a prognostic predictive marker for OSCC.

The Role of Glucose Transporters in Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is a prevalent malignancy associated with a poor prognosis. The Warburg effect can be observed in OSCCs, with tumours requiring a robust glucose supply. Glucose transporters (GLUTs) and sodium-glucose co-transporters (SGLTs) are overexpressed in multiple malignancies, and are correlated with treatment resistance, clinical factors, and poor overall survival (OS). We conducted a systematic review to evaluate the differences in GLUT/SGLT expression between OSCC and normal oral keratinocytes (NOK), as well as their role in the pathophysiology and prognosis of OSCC. A total of 85 studies were included after screening 781 papers. GLUT-1 is regularly expressed in OSCC and was found to be overexpressed in comparison to NOK, with high expression correlated to tumour stage, treatment resistance, and poor prognosis. No clear association was found between GLUT-1 and tumour grade, metastasis, and fluorodeoxyglucose (FDG) uptake. GLUT-3 was less thoroughly studied but could be detected in most samples and is generally overexpressed compared to NOK. GLUT-3 negatively correlated with overall survival (OS), but there was insufficient data for correlations with other clinical factors. Expression of GLUT-2/GLUT-4/GLUT-8/GLUT-13/SGLT-1/SGLT-2 was only evaluated in a small number of studies with no significant differences detected. GLUTs 7 and 14 have never been evaluated in OSCC. In conclusion, the data demonstrates that GLUT-1 and GLUT-3 have a role in the pathophysiology of OSCC and represent valuable biomarkers to aid OSCC diagnosis and prognostication. Other GLUTs are comparatively understudied and should be further analysed because they may hold promise to improve patient care.

Prognostic value of glycolysis markers in head and neck squamous cell carcinoma: a meta-analysis

Glycolysis markers including glucose transporter 1 (GLUT1), monocarboxylate transporter 4 (MCT4), hexokinase 2 (HK2), pyruvate kinase M2 (PKM2) and glucose transporter 4 (GLUT4) play vital roles in head and neck squamous cell carcinoma (HNSCC). However, their prognostic value in HNSCC is still controversial. In this meta-analysis, we searched the PubMed, Web of Science and Cochrane Library databases and included thirty-seven studies (3272 patients) that met the inclusion criteria. Higher expression levels of the glycolysis markers in tumor tissues correlated with poorer overall survival (OS; P < 0.001), disease-free survival (DFS; P = 0.03) and recurrence-free survival (RFS; P < 0.001) of HNSCC patients. Subgroup and sensitivity analyses demonstrated that higher expression levels of GLUT1 (P < 0.001), MCT4 (P = 0.002), HK2 (P = 0.002) and PKM2 (P < 0.001) correlated with poorer OS among HNSCC patients. Higher expression of MCT4 (P < 0.001) and PKM2 (P = 0.008) predicted poorer DFS among HNSCC patients. However, GLUT4 expression levels did not associate with clinical outcomes in HNSCC patients. These results demonstrate that glycolysis markers, such as GLUT1, MCT4, HK2 and PKM2, are potential prognostic predictors and therapeutic targets in HNSCC.

Can Increased Metabolic Status be a Grading Tool for Oral Squamous Cell Carcinoma? A Glucose Transporter 1 Immunoexpression Study

Background:

Glucose transporter-1 (GLUT-1) is a GLUT protein whose expression is upregulated in malignant cells where enhanced uptake of glucose is observed.

Aim:

The aim of this study is to evaluate the expression of GLUT-1 protein in oral squamous cell carcinoma (OSCC) tissue sections using immunohistochemistry and to describe the relationship between increased metabolic status and the grades of OSCC.

Materials and Methods:

This is cross-sectional study with 76 formalin-fixed paraffin-embedded tissue blocks of OSCC, obtained from the archives of the department. All the cases were scored using Bryne's grading system by three oral pathologists independently. The tissue sections were then stained using immunohistochemistry with anti-GLUT-1 rabbit monoclonal antibody.

Results:

Staining intensity and localization of positively stained slides were evaluated. Overall, a significant correlation between Bryne's histopathological grading system for OSCC and GLUT-1 immunohistochemical expression was observed. Thus, high GLUT-1 expressions are observed with increasing grades of OSCC.

Conclusion:

This study shows that a significant positive correlation exists between GLUT-1 immunoexpression and histological grading of OSCC. Thus, GLUT-1 expression can be used as a diagnostic adjunct and prognostic marker for OSCC patients.

Glut 1 in Cancer Cells and the Inhibitory Action of Resveratrol as A Potential Therapeutic Strategy

An important hallmark in cancer cells is the increase in glucose uptake. GLUT1 is an important target in cancer treatment because cancer cells upregulate GLUT1, a membrane protein that facilitates the basal uptake of glucose in most cell types, to ensure the flux of sugar into metabolic pathways. The dysregulation of GLUT1 is associated with numerous disorders, including cancer and metabolic diseases. There are natural products emerging as a source for inhibitors of glucose uptake, and resveratrol is a molecule of natural origin with many properties that acts as antioxidant and antiproliferative in malignant cells. In the present review, we discuss how GLUT1 is involved in the general scheme of cancer cell metabolism, the mechanism of glucose transport, and the importance of GLUT1 structure to understand the inhibition process. Then, we review the current state-of-the-art of resveratrol and other natural products as GLUT1 inhibitors, focusing on those directed at treating different types of cancer. Targeting GLUT1 activity is a promising strategy for the development of drugs aimed at treating neoplastic growth.

Expression of GLUT-1 in oral squamous cell carcinoma in tobacco and non-tobacco users

BACKGROUND

GLUTs are a family of proteins that mediate glucose transport through the membrane, expressed in head and neck squamous cell carcinoma. GLUT-1 positivity in malignant cells indicates increased proliferative activity, energy requirements, aggressive behaviour and poor radiation response.

AIM

To observe the expression of GLUT-1 protein in oral squamous cell carcinoma in tobacco and non-tobacco users and to correlate the expression with histopathological grading and pathological staging.

METHODS

50 cases (25 tobacco and 25 non-tobacco) of oral squamous cell carcinoma, selected during period of August 2014 to July 2015. Histopathological grading, TNM and staging were done. Immunohistochemical staining was performed using standard protocol for paraffin embedded sections. Analysis was performed on SPSS software (Windows version 17.0).

RESULTS

Significant association of GLUT-1 expression was found with history of tobacco (p < 0.001), Bryne's grade (p < 0.001), tumour size (p = 0.001), nodal metastasis (p = 0.022) and stage (p < 0.001). Higher GLUT-1 expression in stage II, stage III and stage IV was found as compared to stage I. GLUT-1 immunoexpression also shows progressive switch from membranous to cytoplasmic to combined location correlating with histopathologic grade and pTNM stage.

CONCLUSION

GLUT-1 expression correlates significantly with histological grade and pTNM staging of oral squamous cell carcinoma. It also significantly correlates with tobacco addiction. Thus, GLUT-1 expression may serve as a biomarker for patients of oral squamous cell carcinoma.

Distribution of Hypoxia-Inducible Factor-1α and Glucose Transporter-1 in Human Tongue Cancers

PURPOSE

Oral squamous cell carcinomas have the potential for rapid and unlimited growth. Therefore, hypoxic tissue areas are common in these malignant tumors and contribute to cancer progression, therapy resistance, and poor outcomes. The aim of the present study was to analyze the gene product distribution of hypoxia-inducible factor-1α (HIF-1α) and glucose transporter-1 (GLUT-1) in cases of tongue squamous cell carcinoma (TSCC) and to identify a preliminary correlation between these proteins and clinical staging and Brynes's histologic grading system (HGS).

MATERIALS AND METHODS

The sample included 57 cases of TSCC. Histologic sections of 3 μm were submitted to the immunoperoxidase method and semiquantitative analysis. The association between HIF-1α and GLUT-1 expression in TSCC and the clinical stage and the HGS of Bryne (1998) was evaluated using the χ(2) test, with the significance level set at 0.05 (α = 0.05).

RESULTS

HIF-1α was mainly expressed in the nucleus/cytoplasm of neoplastic cells, most specimens exhibited diffuse staining in neoplastic cells (84.2%), and focal staining was only observed in perinecrotic areas (15.8%). GLUT-1 was expressed in the cytoplasm and membrane of malignant cells, and diffuse staining was observed in all cases. The intensity of HIF-1α expression correlated significantly with clinical stage (P = .011) and HGS (P = .002). A significant association was observed between the distribution of HIF-1α expression and metastasis (P = .040). Immunoexpression of GLUT-1 correlated significantly with clinical stage (P = .002) and HGS (P = .000). GLUT-1 expression in the peripheral island was predominant in most low-grade tumors (78.6%); in the high-grade cases, the expression prevailed in the location center/periphery (55.8%). Comparison of the location of the tumor island in the different histologic grades showed a statistically significant difference (P = .025).

CONCLUSION

The expression of HIF and GLUT proteins within TSCC appears to be associated with disease stage, grade, and the presence of metastases. Additional studies are needed to evaluate the diagnostic and prognostic uses of these proteins in the treatment of TSCC.

T-type Ca2+ channels in normal and abnormal brain functions

Low-voltage-activated T-type Ca(2+) channels are widely expressed in various types of neurons. Once deinactivated by hyperpolarization, T-type channels are ready to be activated by a small depolarization near the resting membrane potential and, therefore, are optimal for regulating the excitability and electroresponsiveness of neurons under physiological conditions near resting states. Ca(2+) influx through T-type channels engenders low-threshold Ca(2+) spikes, which in turn trigger a burst of action potentials. Low-threshold burst firing has been implicated in the synchronization of the thalamocortical circuit during sleep and in absence seizures. It also has been suggested that T-type channels play an important role in pain signal transmission, based on their abundant expression in pain-processing pathways in peripheral and central neurons. In this review, we will describe studies on the role of T-type Ca(2+) channels in the physiological as well as pathological generation of brain rhythms in sleep, absence epilepsy, and pain signal transmission. Recent advances in studies of T-type channels in the control of cognition will also be briefly discussed.

Prognostic impacts of hypoxic markers in soft tissue sarcoma

Background. We aimed to explore the prognostic impact of the hypoxia-induced factors (HIFαs) 1 and 2, the metabolic HIF-regulated glucose transporter GLUT-1, and carbonic anhydrase IX (CAIX) in non-gastrointestinal stromal tumor soft tissue sarcomas (non-GIST STS). Methods. Duplicate cores with viable tumor tissue from 206 patients with non-GIST STS were obtained and tissue microarrays were constructed. Immunohistochemistry (IHC) was used to evaluate expression of hypoxic markers. Results. In univariate analyses, GLUT-1 (P < 0.001) and HIF-2α (P = 0.032) expression correlated significantly with a poor disease-specific survival (DSS). In the multivariate analysis, however, only high expression of GLUT-1 (HR 1.7, CI 95% 1.1–2.7, P = 0.021) was a significant independent prognostic indicator of poor DSS. Conclusion. GLUT-1 is a significant independent negative prognostic factor in non-GIST STS.

Glucose uptake mediated by glucose transporter 1 is essential for early tooth morphogenesis and size determination of murine molars

Glucose is an essential source of energy for body metabolism and is transported into cells by glucose transporters (GLUTs). Well-characterized class I GLUT is subdivided into GLUTs1-4, which are selectively expressed depending on tissue glucose requirements. However, there is no available data on the role of GLUTs during tooth development. This study aims to clarify the functional significance of class I GLUT during murine tooth development using immunohistochemistry and an in vitro organ culture experiment with an inhibitor of GLUTs1/2, phloretin, and Glut1 and Glut2 short interfering RNA (siRNA). An intense GLUT1-immunoreaction was localized in the enamel organ of bud-stage molar tooth germs, where the active cell proliferation occurred. By the bell stage, the expression of GLUT1 in the dental epithelium was dramatically decreased in intensity, and subsequently began to appear in the stratum intermedium at the late bell stage. On the other hand, GLUT2-immunoreactivity was weakly observed in the whole tooth germs throughout all stages. The inhibition of GLUTs1/2 by phloretin in the bud-stage tooth germs induced the disturbance of primary enamel knot formation, resulting in the developmental arrest of the explants and the squamous metaplasia of dental epithelial cells. Furthermore, the inhibition of GLUTs1/2 in cap-to-bell-stage tooth germs reduced tooth size in a dose dependent manner. These findings suggest that the expression of GLUT1 and GLUT2 in the dental epithelial and mesenchymal cells seems to be precisely and spatiotemporally controlled, and the glucose uptake mediated by GLUT1 plays a crucial role in the early tooth morphogenesis and tooth size determination.

Hypoxia-related protein expression and its clinicopathologic implication in carcinoma of unknown primary

Carcinoma of unknown primary (CUP) is a heterogeneous entity with different clinical and histological features. The aim of this study was to investigate the clinicopathological features and expression of proteins associated with carcinogenesis and tumor environment in different histological subtypes of CUP. Sixty-nine cases of CUP were subjected to immunohistochemistry for EGFR, phospho-EGFR, HER-2, phospho-HER-2, p53, ERCC1, RRM1, REDD1, HIF1α, COX-2, GLUT-1, 14-3-3σ, Phospho-mTOR, Phospho-S6, AMPKα1, Phospho-Akt, PDGF-β receptor, and caveolin-1, and fluorescence in situ hybridization for HER-2 gene amplification. Fourteen (20.3%) cases were poorly differentiated carcinoma, 24 (34.8%) were adenocarcinoma (AD), 17 (24.6%) were squamous cell carcinoma (SC), and 14 (20.3%) were undifferentiated carcinoma (UD). AD were mostly carcinomatosis type, while SC and UD were mostly nodal type (p < 0.001). SC showed more frequent EGFR overexpression (p < 0.001) and Glut-1 (p = 0.001). AD (p = 0.001) and carcinomatosis (p < 0.001) types showed shorter overall survival. SCs expressing Glut-1, HIF1α, and COX2 showed a poor prognosis (p = 0.048, 0.029, and 0.042, respectively). CUP shows various clinicopathological features according to the histological subtypes. SC is mainly associated with nodal metastasis in the head and neck, and frequent EGFR overexpression and Glut-1 expression. Glut-1, HIF1α, and COX2 expression in SC is associated with a poor prognosis.