Analysis of GLUT-1, GLUT-3, and angiogenic index in syndromic and non-syndromic keratocystic odontogenic tumors.

The aim of this study was to evaluate the immunoexpression of glucose transporters 1 (GLUT-1) and 3 (GLUT-3) in keratocystic odontogenic tumors associated with Gorlin syndrome (SKOTs) and non-syndromic keratocystic odontogenic tumors (NSKOTs), and to establish correlations with the angiogenic index. Seventeen primary NSKOTs, seven recurrent NSKOTs, and 17 SKOTs were selected for the study. The percentage of immunopositive cells for GLUT-1 and GLUT-3 in the epithelial component of the tumors was assessed. The angiogenic index was determined by microvessel count. The results were analyzed statistically using the nonparametric Kruskal-Wallis test and Spearman's correlation test. High epithelial immunoexpression of GLUT-1 was observed in most tumors (p = 0.360). There was a higher frequency of negative cases for GLUT-3 in all groups. The few GLUT-3-positive tumors exhibited low expression of this protein in epithelial cells. No significant difference in the angiogenic index was observed between groups (p = 0.778). GLUT-1 expression did not correlate significantly with the angiogenic index (p > 0.05). The results suggest that the more aggressive biological behavior of SKOTs when compared to NSKOTs may not be related to GLUT-1 or GLUT-3 expression. GLUT-1 may play an important role in glucose uptake by epithelial cells of KOTs and this process is unlikely related to the angiogenic index. GLUT-1 could be a potential target for future development of therapeutic strategies for KOTs.

Analysis of GLUT-1, GLUT-3, and angiogenic index in syndromic and non-syndromic keratocystic odontogenic tumors

Abstract The aim of this study was to evaluate the immunoexpression of glucose transporters 1 (GLUT-1) and 3 (GLUT-3) in keratocystic odontogenic tumors associated with Gorlin syndrome (SKOTs) and non-syndromic keratocystic odontogenic tumors (NSKOTs), and to establish correlations with the angiogenic index. Seventeen primary NSKOTs, seven recurrent NSKOTs, and 17 SKOTs were selected for the study. The percentage of immunopositive cells for GLUT-1 and GLUT-3 in the epithelial component of the tumors was assessed. The angiogenic index was determined by microvessel count. The results were analyzed statistically using the nonparametric Kruskal-Wallis test and Spearman’s correlation test. High epithelial immunoexpression of GLUT-1 was observed in most tumors (p = 0.360). There was a higher frequency of negative cases for GLUT-3 in all groups. The few GLUT-3-positive tumors exhibited low expression of this protein in epithelial cells. No significant difference in the angiogenic index was observed between groups (p = 0.778). GLUT-1 expression did not correlate significantly with the angiogenic index (p > 0.05). The results suggest that the more aggressive biological behavior of SKOTs when compared to NSKOTs may not be related to GLUT-1 or GLUT-3 expression. GLUT-1 may play an important role in glucose uptake by epithelial cells of KOTs and this process is unlikely related to the angiogenic index. GLUT-1 could be a potential target for future development of therapeutic strategies for KOTs.

Expression of glucose transporters 1 and 3 in metastatic and non-metastatic lower lip squamous cell carcinoma.

This study aimed to evaluate the immunoexpression of glucose transporters 1 (GLUT-1) and 3 (GLUT-3) in metastatic and non-metastatic lower lip squamous cell carcinoma (LLSCC). Twenty LLSCCs with regional nodal metastasis and 20 LLSCCs without metastasis were selected. The distribution of staining and the percentage of GLUT-1 and GLUT-3 staining in each tumor core and at the deep invasive front were assessed. Most tumors (70%) exhibited peripheral staining for GLUT-1 in nests, sheets and islands of neoplastic cells, whereas predominantly central staining was observed for GLUT-3 (72.5%). A high percentage of GLUT-1-positive cells was observed at the deep invasive front and in the tumor core of metastatic and non-metastatic tumors (p>0.05). The percentage of GLUT-1-positive cells was much higher than that of GLUT-3-positive cells both in the deep invasive front (p<0.001) and in the tumor core (p<0.001) of LLSCCs. No significant differences in the percentage of GLUT-1- and GLUT-3-positive cells were observed according to nodal metastasis, clinical stage or histological grade of malignancy (p>0.05). In conclusion, the results of the present study suggest an important role of GLUT-1 in glucose uptake in LLSCCs, although this protein does not seem to be involved in the progression of these tumors. On the other hand, GLUT-3 expression may represent a secondary glucose uptake mechanism in LLSCCs.

Maximum standardized uptake value on 18F-fluoro-2-deoxy-glucose positron emission tomography/computed tomography and glucose transporter-1 expression correlates with survival in invasive ductal carcinoma of the pancreas.

OBJECTIVES: The purpose of this study was to assess the correlations among the maximum standardized uptake value (SUVmax) on 18F-fluoro-2-deoxy-glucose positron emission tomography/computed tomography (FDG-PET/CT); the expressions of glucose transporter 1 (GLUT-1), glucose transporter 3, and epidermal growth factor receptor (EGFR); as well as prognosis in patients with invasive ductal carcinoma of the pancreas. METHODS: A total of 41 patients with surgically resected and histologically proven invasive ductal carcinoma of the pancreas who underwent preoperative FDG-PET/CT were assessed. The SUVmax at the primary tumor site was measured by FDG-PET/CT, and immunohistochemical staining of tumor sections was performed for GLUT-1, glucose transporter 3, and EGFR. RESULTS: Higher FDG uptake (SUVmax, >3.40) and GLUT-1 expression were significantly associated with shorter overall survival (P < 0.05). The SUVmax was not found to be significantly correlated with clinicopathological characteristics such as TNM classification, lymph node metastasis, and tumor differentiation. The EGFR expression was significantly correlated with the SUVmax (P = 0.024). CONCLUSIONS: Higher FDG uptake and GLUT-1 expression in invasive ductal carcinoma of the pancreas seems to be an important prognostic factor. In addition, the EGFR expression was significantly correlated with the SUVmax.

Freezability prediction of boar ejaculates assessed by functional sperm parameters and sperm proteins.

The objective of this work was to look for useful predictive indicators of the potentially "good" or "poor" ability of a boar ejaculate to sustain cryopreservation by assessing both the conventional sperm quality parameters (Study 1) and the immunolabeling of three proteins involved in the physiology of the sperm cell: GLUT3, HSP90AA1 and Cu/ZnSOD (Study 2). Study 1 was carried out in three different steps during the cryopreservation process of the sperm-rich fraction of 29 Piétrain boar ejaculates (17 degrees C, 5 degrees C, and 240min postthaw). These ejaculates were clustered based on sperm quality parameters analyzed at 240min postthaw, obtaining 16 good freezability ejaculates (GFEs) and 13 poor freezability ejaculates (PFEs). The sperm linearity (LIN) and the straightforward (STR) indexes at 5 degrees C showed higher hyperactivated movement in the PFEs than in the GFEs, which suggests that analyzing these sperm kinematic parameters could be a useful tool for predicting the potential freezability of an ejaculate. This statement was demonstrated by grouping the 29 ejaculates into two clusters (A and B) based on LIN and STR values assessed after 30 min at 5 degrees C, which resulted in around 72% of coincidence with the GFE and PFE groups. Study 2, performed at 17 degrees C and 240 min postthaw, revealed no differences between GFEs and PFEs in the immunolabeling of the three proteins within a same step, in terms of location and reactivity, although reactivity was generally weaker at 240 min postthaw in both groups. Additional studies on Western blot are currently being carried out with the objective to quantify the expression of the three proteins in GFEs and PFEs in the three steps of the cryopreservation process.

Expressions of glucose transporter Types 1 and 3 and hexokinase-II in diffuse large B-cell lymphoma and other B-cell non-Hodgkin's lymphomas.

INTRODUCTION: Diffuse large B-cell lymphoma (DLBCL) has been reported to show higher uptake of 2-deoxy-2-F18-fluoro-d-glucose (FDG) by positron emission tomography than other B-cell non-Hodgkin's lymphomas (non-DLBCL). The authors addressed the mechanism of FDG uptake in DLBCL by immunostaining for glucose transporter Types 1 (Glut-1) and 3 (Glut-3) and hexokinase-II (HK-II) in excised lymphoma tissues. METHODS: Sixteen B-cell non-Hodgkin's lymphoma patients (11 DLBCL and 5 non-DLBCL patients) were included in the study because the lymphoma tissues obtained by excision were eligible for immunostaining. The expressions of Glut-1, Glut-3 and HK-II were assessed regarding the percentages of positively stained lymphoma cells (%expression), the staining intensities (none=0, weak=1, moderate=2 and strong=3) and the staining patterns (membranous or cytoplasmic) and compared between DLBCL and non-DLBCL. RESULTS: Glut-1 was not expressed at all in DLBCL or non-DLBCL, and their Glut-3 expressions were not significantly different (P>.05) with respect to %expression (mean+/-S.E.M., 73.6+/-7.3% vs. 72.0+/-3.7%), staining intensity (2.5+/-0.2 vs. 2.6+/-0.2) and staining pattern (membranous pattern dominant; 54.5% vs. 60.0%). However, DLBCL expressed more HK-II than non-DLBCL, i.e., %expression (45.2+/-11.5% vs. 17.0+/-15.8%, P=.0275) and staining intensity (2.3+/-0.2 vs. 0.6+/-0.4, P=.0032). HK-II showed a cytoplasmic location in DLBCL and non-DLBCL. CONCLUSIONS: HK-II and Glut-3 contribute significantly to FDG uptake in DLBCL. DLBCL may have higher FDG uptake because it expresses more HK-II, whereas Glut-1 appears to play no role in FDG uptake in B-cell non-Hodgkin's lymphoma.

Influence of blood glucose on the expression of glucose trans-porter proteins 1 and 3 in the brain of diabetic rats.

BACKGROUND: The delivery of glucose from the blood to the brain involves its passage across the endothelial cells of the blood-brain barrier (BBB), which is mediated by the facilitative glucose transporter protein 1 (GLUT(1)), and then across the neural cell membranes, which is mediated by GLUT(3). This study aimed to evaluate the dynamic influence of hyperglycemia on the expression of these GLUTs by measuring their expression in the brain at different blood glucose levels in a rat model of diabetes. This might help to determine the proper blood glucose threshold level in the treatment of diabetic apoplexy. METHODS: Diabetes mellitus was induced with streptozotocin (STZ) in 30 rats. The rats were randomly divided into 3 groups: diabetic group without blood glucose control (group DM1), diabetic rats treated with low dose insulin (group DM2), and diabetic rats treated with high dose insulin (group DM3). The mRNA and protein levels of GLUT(1) and GLUT(3) were assayed by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry, respectively. RESULTS: Compared with normal control rats, the GLUT(1) mRNA was reduced by 46.08%, 29.80%, 19.22% (P < 0.01) in DM1, DM2, and DM3 group, respectively; and the GLUT(3) mRNA was reduced by 75.00%, 46.75%, and 17.89% (P < 0.01) in DM1, DM2, and DM3 group, respectively. The abundance of GLUT(1) and GLUT(3) proteins had negative correlation with the blood glucose level (P < 0.01). The density of microvessels in the brain of diabetic rats did not change significantly compared with normal rats. CONCLUSIONS: Chronic hyperglycemia downregulates GLUT(1) and GLUT(3) expression at both mRNA and protein levels in the rat brain, which is not due to the decrease of the density of microvessels. The downregulation of GLUT(1) and GLUT(3) expression might be the adaptive reaction of the body to prevent excessive glucose entering the cell that may lead to cell damage.

Effects of cryopreservation on semen quality and the expression of sperm membrane hexose transporters in the spermatozoa of Iberian pigs.

This study evaluated the effects of cooling, freezing and thawing on the plasma membrane integrity, kinetics and expression of two sugar transporters glucose transporter-3 and -5 (GLUT-3 and GLUT-5) in spermatozoa from Iberian boars. Semen samples were collected twice weekly from eight young, fertile Iberian boars of the 'Entrepelado' and 'Lampiño' breeds. The samples were suspended in a commercial extender and refrigerated to 17 degrees C for transport to the laboratory (step A), where they were further extended with a lactose-egg yolk-based extender and chilled to 5 degrees C (step B) prior to freezing in the presence of glycerol (3%). Spermatozoa were assessed for plasma membrane integrity and sperm motility at each of the steps, including post-thaw (step C). Aliquots were also prepared for immunocytochemical localisation of the sugar transporters (fixed and thin smears for transmission and scanning electron microscopy levels respectively) and for SDS-PAGE electrophoresis and subsequent western blotting, using the same antibodies (rabbit anti-GLUT-3 and anti-GLUT-5 polyclonal antibodies). The results showed lower percentages of progressively motile spermatozoa at step C in both breeds, while the percentage of live spermatozoa was significantly lower only in the 'Entrepelado' breed. The results obtained from electron microscopy clearly showed that Iberian boar spermatozoa expressed the hexose transporters, GLUT-3 and GLUT-5. The pattern of expression, in terms of location and concentration, was characteristic in each case but, in the case of isoform GLUT-5, it remained constant during the different steps of freezing-thawing protocol. These results indicate that cryopreservation affects the status of sperm cells of Iberian boars by altering the distribution of some membrane receptors and decreasing the percentage values of parameters linked to sperm quality.

Glucose uptake inhibitor sensitizes cancer cells to daunorubicin and overcomes drug resistance in hypoxia.

PURPOSE: A high-rate glycolysis is a fundamental property of solid tumors and is associated with an over-expression of glucose transporters and glycolytic enzymes. We hypothesize that over-expression of glucose transporters in tumors prevents apoptosis, promotes cancer cell survival, and confers drug resistance. Inhibition of glucose transporter will preferentially sensitize the anticancer effects of chemotherapeutic drugs to overcome drug resistance in hypoxia. METHODS: Glucose transporter expressions were detected in cancer tissues and NCI 60 cancer cells with immunostaining and DNA microarray. Glucose uptake was measured with 3H-2-deoxy-glucose. Cytotoxicity of daunorubicin (DNR) in combination of glucose inhibitor was detected by MTS assay under hypoxic condition. Early stage apoptosis was monitored with Annexin V-FITC staining. RESULTS: Immunostaining showed that GLUT1 was significantly increased in hypoxic regions of the human colon and breast tumors. The expression profiles of all glucose transporters in NCI 60 cancer cells exhibited distinct expression patterns. Phloretin exhibited more than 60% glucose uptake inhibition. Hypoxia conferred two to fivefold higher drug resistance in SW620 and K562 to DNR. Inhibition of glucose uptake by phloretin sensitized cancer cells to DNR for its anticancer activity and apoptosis to overcome drug resistance only under hypoxia. CONCLUSION: Cancer cells heavily rely on glucose transporters for glucose uptake to facilitate a high-rate glycolysis under hypoxia for their survival and drug resistance. Combination of glucose transporter inhibitors and chemotherapeutic drugs may provide a preferential novel therapeutic strategy to overcome drug resistance in hypoxia.

Asymmetric subcellular distribution of glucose transporters in the endothelium of small contractile arteries.

The authors have recently reported the presence and asymmetric distribution of the glucose transporters GLUT-1 to -5 and SGLT-1 in the endothelium of rat coronary artery (Gaudreault et al. 2004, Diabetologica, 47, 2081-2092). In the present study the authors investigate and compare the presence and subcellular distribution of the classic glucose transporter isoforms in endothelial cells of cerebral, renal, and mesenteric arteries. The GLUTs and SGLT-1 were examined with immunohistochemistry and wide-field fluorescence microscopy coupled to deconvolution in en face preparation of intact artery. We identified GLUT-1 to -5 and SGLT-1 in the endothelial cells of all three vascular beds. The relative level of expression for each isoform was found comparable amongst arteries. Clusters of the glucose transporter isoforms were found at a high density in proximity to the cell-to-cell junctions. In addition, a consistent asymmetric distribution of GLUT-1 to -5 was found, predominantly located on the abluminal side of the endothelium in all three vascular beds examined (ranging from 68% to 91%, p<.05). The authors conclude that the expression and subcellular distribution of glucose transporters are similar in endothelial cells from vascular beds of comparable diameter and suggest that their subcellular organization may facilitate transendothelial transport of glucose in small contractile arteries.

The prognostic value of endogenous hypoxia-related markers for head and neck squamous cell carcinomas treated with ARCON.

BACKGROUND AND PURPOSE: Hypoxic radioresistance is an important cause for treatment failure in a number of tumor types including head and neck cancers. Recent studies suggest that outcome can be improved by oxygenation modifying treatments such as ARCON. A robust endogenous marker of hypoxia might be a valuable aid to select patients for such treatments. The aim of this investigation was to study associations between the putative endogenous hypoxia markers CA-IX, Glut-1 and Glut-3 and clinical tumor and patient characteristics and to evaluate the prognostic value of these markers. PATIENTS AND METHODS: Tumor biopsies from 58 patients treated with ARCON in a phase II trial were included. Tumor sections were immunohistochemically stained for CA-IX, Glut-1 and Glut-3. Sections were scored for relative tumor area stained by the markers (CA-IX and Glut-3) and for intensity of staining (Glut-1 and Glut-3). Further, sections were stained for CD34, an endothelial marker to assess microvascular density. RESULTS: Staining of CA-IX and Glut-3 was observed at some distance from vessels and adjacent to necrosis. Glut-1 staining was generally very diffuse. The distribution of clinical characteristics was equal between tumors with high and low marker expression. Significant differences were found for locoregional control (P = 0.04) and for freedom of distant metastases (P = 0.02) in favour of patients with high CA-IX positivity (>25% of tumor area). High Glut-3 expression was associated with a better locoregional control (P = 0.04). Higher Glut-1 intensity was associated with an increased rate of distant metastases (P = 0.0005) and a worse overall survival (P = 0.001). CONCLUSIONS: The inconsistent associations with outcome of CA-IX and the glucose transporters indicate that different factors play a role in up-regulation of these markers. Compared to studies with conventional treatment, the correlation between CA-IX expression and Glut-3 expression and outcome was reversed after treatment with ARCON. This does not support the potential of any of these proteins as very specific and robust hypoxia markers.

Hexose transporters GLUT1 and GLUT3 are colocalized with hexokinase I in caveolae microdomains of rat spermatogenic cells.

Postmeiotic spermatogenic cells, but not meiotic spermatogenic cells respond differentially with glucose-induced changes in [Ca2+]i indicating a differential transport of glucose via facilitative hexose transporters (GLUTs) specifically distributed in the plasma membrane. Several studies have indicated that plasma membrane in mammalian cells is not homogeneously organized, but contains specific microdomains known as detergent-resistant membrane domains (DRMDs), lipid rafts or caveolae. The association of these domains and GLUTs isoforms has not been characterized in spermatogenic cells. We analyzed the expression and function of GLUT1 and GLUT3 in isolated spermatocytes and spermatids. The results showed that spermatogenic cells express both glucose transporters, with spermatids exhibiting a higher affinity glucose transport system. In addition, spermatogenic cells express caveolin-1, and glucose transporters colocalize with caveolin-1 in caveolin-enriched membrane fractions. Experiments in which the integrity of caveolae was disrupted by pretreatment with methyl-beta-cyclodextrin, indicated that the involvement of cholesterol-enriched plasma membrane microdomains were involved in the localization of GLUTs and uptake of 2-deoxyglucose. We also observed cofractionation of GLUT3 and caveolin-1 in low-buoyant density membranes together with their shift to higher densities after methyl-beta-cyclodextrin treatment. GLUT1 was found in all fractions isolated. Immunofluorescent studies indicated that caveolin-1, GLUT1, and hexokinase I colocalize in spermatocytes while caveolin-1, GLUT3, and hexokinase I colocalize in spermatids. These findings suggest the presence of hexose transporters in DRMDs, and further support a role for intact caveolae or cholesterol-enriched membrane microdomains in relation to glucose uptake and glucose phosphorylation. The results would also explain the different glucose-induced changes in [Ca2+]i in both cells.

Effects of different antipsychotics and the antidepressant mirtazapine on glucose transporter mRNA levels in human blood cells.

A relationship between cell metabolism and the expression of glucose transporters (GLUT) has been reported. On the other side, treatment with some antipsychotics has been associated with an increased incidence of hyperglycemia and new-onset type 2 diabetes. We here examined the effects of different concentrations of the conventional antipsychotic haloperidol (400 and 800 microg/ml), of the atypical antipsychotics clozapine (100 and 200 microg/ml) and olanzapine (100 and 200 microg/ml) as well as of the antidepressant mirtazapine (10(-7) mol) on the mRNA levels of GLUT1-5 in the human leukemic blood cell line U937 after incubation for 48 h. After experimental treatment, significant increases were detected by ANOVA and appropriate post-hoc tests for mirtazapine in GLUT4 mRNA levels as well as for haloperidol 400 and 800 microg/ml, olanzapine 200 microg/ml, and mirtazapine in GLUT5 mRNA levels. ANOVAs revealed no statistically significant changes in GLUT1-3 and beta-actin mRNA levels. These findings suggest that direct effects of psychotropic drugs on cellular GLUT4 and GLUT5 may be involved in the metabolic dysfunctions occurring during psychopharmacological treatment.