Gold Nanoparticle Delivery of Glut1 SiRNA Facilitates Glucose Starvation Therapy in Lung Cancer.

Glucose transporter protein-1 (Glut1), is highly expressed in many cancer types and plays a crucial role in cancer progression through enhanced glucose transport. Its overexpression is associated with aggressive tumor behavior and poor prognosis. Herein, the nucleic acids modified gold nanoparticles (AuNPs) was synthesized to deliver small interfering RNA (siRNA) against Glut1 by microRNA 21 (miR-21) triggers toehold-mediated strand displacement reaction for lung cancer starvation therapy. Overexpression of miR-21 triggers toehold-mediated strand displacement, releasing the siRNA to knockdown of Glut1 in cancer cell instead of normal cell. Furthermore, the glucose oxidase-like activity of the AuNPs accelerates intracellular glucose consumption, promoting cancer cell starvation. The engineered AuNPs@anti-miR-21/siGlut1 complex inhibits cancer cell proliferation, xenograft tumor growth and promotes apoptosis through glucose starvation and ROS cascade signaling, underscoring its potential as an effective therapeutic strategy for lung cancer.

Spectrins: a structural platform for stabilization and activation of membrane channels, receptors and transporters.

This review focuses on structure and functions of spectrin as a major component of the membrane skeleton. Recent advances on spectrin function as an interface for signal transduction mediation and a number of data concerning interaction of spectrin with membrane channels, adhesion molecules, receptors and transporters draw a picture of multifaceted protein. Here, we attempted to show the current depiction of multitask role of spectrin in cell physiology. This article is part of a Special Issue entitled: Reciprocal influences between cell cytoskeleton and membrane channels, receptors and transporters. Guest Editor: Jean Claude Hervé.

Immunocytochemical analysis of glucose transporter protein-1 (GLUT-1) in typical, brain invasive, atypical and anaplastic meningioma.

Glucose transporter-1 (GLUT-1) is one of the major isoforms of the family of glucose transporter proteins that facilitates the import of glucose in human cells to fuel anaerobic metabolism. The present study was meant to determine the extent of the anaerobic/hypoxic state of the intratumoral microenvironment by staining for GLUT-1 in intracranial non-embolized typical (WHO grade I; n = 40), brain invasive and atypical (each WHO grade II; n = 38) and anaplastic meningiomas (WHO grade III, n = 6). In addition, GLUT-1 staining levels were compared with the various histological criteria used for diagnosing WHO grade II and III meningiomas, namely, brain invasion, increased mitotic activity and atypical cytoarchitectural change, defined by the presence of at least three out of hypercellularity, sheet-like growth, prominent nucleoli, small cell change and "spontaneous" necrosis. The level of tumor hypoxia was assessed by converting the extent and intensity of the stainings by multiplication in an immunoreactive score (IRS) and statistically evaluated. The results were as follows. (1) While GLUT-1 expression was found to be mainly weak in WHO grade I meningiomas (IRS = 1-4) and to be consistently strong in WHO grade III meningiomas (IRS = 6-12), in WHO grade II meningiomas GLUT-1 expression was variable (IRS = 1-9). (2) Histologically typical, but brain invasive meningiomas (WHO grade II) showed no or similarly low levels of GLUT-1 expression as observed in WHO grade I meningiomas (IRS = 0-4). (3) GLUT-1 expression was observed in the form of a patchy, multifocal staining reaction in 76% of stained WHO grade I-III meningiomas, while diffuse staining (in 11%) and combined multifocal and areas of diffuse staining (in 13%) were only detected in WHO grades II and III meningiomas, except for uniform staining in angiomatous WHO grade I meningioma. (4) "Spontaneous" necrosis and small cell change typically occurred away from the intratumoral capillary network embedded within the pattern of GLUT-1 staining. Taken together, GLUT-1 staining cannot be applied as a substitute for histologic grading in order to predict tumor behavior. However, assessment of tumor hypoxia in association with "spontaneous" necrosis and foci of small cell change may substantially contribute to the neuropathologic diagnosis of WHO grades II and III meningioma.

Expression of glucose transporter protein 1 and p63 in serous ovarian tumor.

AIM: It has been shown that glycolytic metabolism is increased in malignant cells. Cancer cell growth is an energy-related process supported by an increased glucose metabolism. In addition, p63, a known homolog of p53, is expressed predominantly in basal cell and squamous cell carcinomas. The purpose of this study was to evaluate the expression of glucose transporter protein 1 (GLUT1) and p63 in patients with serous ovarian tumor (benign, borderline and malignant) and study their close relationship with the malignant transformation of serous ovarian tumors. METHODS: Two hundred formalin-fixed, paraffin-embedded sections were immunostained with rabbit anti-GLUT1 polyclonal antibody and mouse anti-p63 monoclonal antibody using the streptavidin-biotin method. The samples were as follows: 40 normal ovarian tissues, 40 serous cystadenomas, 40 borderline serous cystadenomas and 80 serous cystadenocarcinomas were stained. RESULT: Normal ovarian tissues showed completely negative staining for GLUT1 and p63. However, from benign serious cystadenomas, borderline cystadenomas to cystadenocarcinomas, the expression of GLUT1 and p63 grew stronger (P < 0.05). Moreover, the intensity staining of GLUT1 maintained a significant association with the expression of p63 (P < 0.05). In χ²-test analysis, expression of borderline cystadenomas and cystadenocarcinomas, intraperitoneal implants, ascites, lymph node status and International Federation of Gynecology and Obstetrics (FIGO) stage and GLUT1 expression levels have an appalling significance (P < 0.05), while FIGO stage, intraperitoneal implants and lymph node status except patient age and ascites have a statistical significance with the expression of p63 levels (P < 0.05). CONCLUSION: Our findings show a progressive increase in the expression of GLUT1 and p63 from the benign serous cystadenomas, borderline cystadenomas to cystadenocarcinomas. Overexpression of GLUT1 and p63 are associated with the histology FIGO stage and metastasis of the tumors. These data suggested that the expression of GLUT1 and p63 may be closely related to the malignant transformation of serous ovarian tumors. However, the relative importance of GLUT1 and p63 in ovarian serous tumor development and tumorigenesis remains mostly unclear and awaits further investigation.

Recombinant Adenovirus-Mediated HIF-lα Ameliorates Neurological Dysfunction by Improving Energy Metabolism in Ischemic Penumbra After Cerebral Ischemia-Reperfusion in Rats.

Background: Hypoxia inducible factor-1α (HIF-1α) regulates glucose metabolism during ischemia. This study investigated the effect of recombinant adenovirus HIF-1ɑ on neurological function and energy metabolism in a rat cerebral ischemia-reperfusion model. Methods: Rats were divided into four groups: sham-operated (Sham) group, cerebral ischemia-reperfusion (CIR) group, recombinant adenovirus empty vector (Ad) group, and recombinant adenovirus-mediated HIF-1α (AdHIF-1α) group. The AdHIF-1α group and the Ad group were injected with AdHIF-1α and Ad in the lateral ventricle. The mNSS was performed at post-ischemia day 0 (P0) and P1, P14 and P28. At P14, the cerebral infarct volume was compared. At P28, HE staining, Nissl stains and TUNEL staining were performed. The expression of HIF-1α, GLUT1 and PFKFB3 were evaluated by Western Blot and immunohistochemistry. High performance liquid chromatography (HPLC) was used to determine the expression of GLUT1 and PFKFB3, and the level of energy metabolites: ATP, ADP and AMP. Results: mNSS scores in the AdHIF-1α group were consistently lower than those in the CIR and Ad groups from P14 (P < 0.05) and Ad groups (P < 0.05). The cerebral infarct volume was reduced in the AdHIF-1α group compared with that in CIR group and Ad group (P < 0.05). At P28, HE showed better pathological changes in AdHIF-1α group. The number of Nissl bodies was increased in the AdHIF-1α group compared with the CIR and Ad groups (P < 0.05). The number of apoptotic cells in the AdHIF-1α group was fewer than that in the CIR and Ad groups (P < 0.05). The expression of HIF-1α, GLUT1 and PFKFB3 was significantly higher in the AdHIF-1α group compared with the CIR and Ad groups (P < 0.05). The ATP, ADP and AMP in the ischemic penumbra were also higher in the AdHIF-1α group (P < 0.05). Conclusion: HIF-lα promoted neurological function recovery and decreased cerebral infarct volume in rats after cerebral ischemia-reperfusion injury by improving energy metabolism.

Glioblastoma Contains Topologically Distinct Proliferative and Metabolically Defined Subpopulations of Nestin- and Glut1-Expressing Cells.

The difficulty in treatment of glioblastoma is a consequence of its natural infiltrative growth and the existence of a population of therapy-resistant glioma cells that contribute to growth and recurrence. To identify cells more likely to have these properties, we examined the expression in tumor specimens of several protein markers important for glioma progression including the intermediate filament protein, Nestin (NES), a glucose transporter (Glut1/SLC2A1), the glial lineage marker, glial fibrillary acidic protein, and the proliferative indicator, Ki-67. We also examined the expression of von Willebrand factor, a marker for endothelial cells as well as the macrophage/myeloid markers CD163 and CD15. Using a multicolor immunofluorescence and hematoxylin and eosin staining approach with archival formalin-fixed, paraffin embedded tissue from primary, recurrent, and autopsy IDH1 wildtype specimens combined with high-resolution tissue image analysis, we have identified highly proliferative NES(+)/Glut1(-) cells that are preferentially perivascular. In contrast, Glut1(+)/NES(-) cells are distant from blood vessels, show low proliferation, and are preferentially located at the borders of pseudopalisading necrosis. We hypothesize that Glut1(+)/NES(-) cells would be naturally resistant to conventional chemotherapy and radiation due to their low proliferative capacity and may act as a reservoir for tumor recurrence.

Relationships between expression of glucose transporter protein-1 and hypoxia inducible factor-1α, prognosis and 18F-FDG uptake in laryngeal and hypopharyngeal carcinomas.

BACKGROUND: We investigated the relationships between glucose transporter protein-1 (GLUT-1) and hypoxia inducible factor-1α (HIF-1α) expression, 2-deoxy-2-[18F]-fluoro-D-glucose (18F-FDG) uptake and prognosis in laryngeal and hypopharyngeal carcinomas patients. METHODS: Levels of GLUT-1 and HIF-1α proteins were examined by immunohistochemistry in 55 patients with laryngeal and hypopharyngeal carcinomas. All patients underwent 18F-FDG positron emission tomography-computed tomography (PET/CT) before surgery. RESULTS: Levels of GLUT-1 and HIF-1α in laryngeal and hypopharyngeal carcinomas were significantly higher than in vocal cord polyps. GLUT-1 expression was correlated with HIF-1α expression (r=0.571, P<0.001) and SUVmax (r=0.495, P<0.001). HIF-1α expression was not correlated with SUVmax (P=0.199). HIF-1α expression was correlated with tumor size (r=0.351, P=0.009). Multivariate analysis demonstrated that treatment method (P=0.025), tumor size (P=0.008), GLUT-1 expression (P=0.032), and HIF-1α expression (P=0.032) were correlated with overall survival (OS). CONCLUSIONS: Treatment method, tumor size, GLUT-1 and HIF-1α levels were correlated with prognosis in laryngeal and hypopharyngeal carcinomas patients.

Transporter Gene Expression and Transference of Fructose in Broiler Chick Intestine.

Recent studies have suggested that a high-fructose diet leads to the development of metabolic syndrome in mammals. However, relatively little information is available regarding the absorption of fructose in the chicken intestine. We therefore investigated fructose absorption and its transporters in the chicken small intestine. The gene expression of three transporters (glucose transporter protein member 2 and 5 and sodium-dependent glucose transporter protein 1) in the jejunum of fasted chicks were lower than those in chicks fed ad libitum. The everted intestinal sacs (in vitro method for investigating intestinal absorption) showed that the concentration of fructose uptake rapidly increased within 15 min after incubation, and then gradually increased until 60 min. After 15 min of incubation, fructose uptake in the ad libitum chick intestine was approximately 2-fold that in the fasted intestine and was less than half of the glucose uptake in the ad libitum chick intestine. Our results suggest that fructose is absorbed in the small intestine of chicks and that uptake is decreased by fasting treatment with decreases in the mRNA expression of related transporters.

Clinicopathological significance of glucose transporter protein-1 overexpression in human osteosarcoma.

Although previous studies have demonstrated that Glut-1 is the predominant glucose transporter, is significantly overexpressed in various types of tumor and is correlated with poor prognosis, the potential function and clinical value of Glut-1 expression in osteosarcoma remains largely unclear. In particular, the prospective associations between Glut-1 expression levels and clinicopathological factors remains to be elucidated. In the present study, immunohistochemistry was performed to detect Glut-1 protein expression in 51 paired osteosarcoma specimens and adjacent non-cancerous tissues, and reverse transcription-quantitative polymerase chain reaction analysis was performed to examine Glut-1 mRNA expression levels in 6 pairs of these tissues. Statistical analyses were conducted to determine the associations between Glut-1 expression and various clinicopathological parameters. Glut-1 protein was revealed to be overexpressed in 38 (74.5%) osteosarcoma tissues, but only in 6 (11.8%) adjacent non-cancerous tissues. Glut-1 mRNA levels were also upregulated in osteosarcoma tissues compared with adjacent non-cancerous tissues. While there were no clear statistical relationships between Glut-1 expression and patient sex, resection, tumor location, size, T stage and adjuvant treatment, Glut-1 expression levels were significantly associated with age, tumor-node-metastasis stage, lymph node metastasis and survival. The median survival time in patients with low Glut-1 expression levels was longer than in patients with a high expression level. Glut-1 was significantly overexpressed in osteosarcoma tissues, and Glut-1 expression was associated with clinicopathological factors which upregulate the invasion and metastasis of osteosarcoma, and may be a potential predictor of survival in patients with osteosarcoma.

Silencing of Glucose Transporter Protein-1 by RNA Interference Inhibits Human Osteosarcoma Mg63 Cells Growth in vivo.

While knock-down of glucose transporter protein 1 (GLUT-1) inhibited various human cancer cell growth in vitro and in vivo, including osteosarcoma cell growth in vitro, there has been no report on whether knock-down of GLUT-1 by siRNA may inhibit osteosarcoma cell growth in vivo. We hypothesized that siRNA may inhibit osteosarcoma cell growth in vivo. We introduced siRNA-GLUT-1 by lentivirus into MG63 osteosarcoma cells which were xenograted into nude mice. Immunohistochemical staining, Western blot and reverse transcriptase quantitative (RT-qPCR) were used to determine GLUT-1 protein and mRNA expression of the tumor cells. The results showed the tumor volume of GLUT-1-siRNA-MG63 cells xenorafted nude mice was significantly less than that of siGFP-MG63 or MG63 cells xenografted nude mice (P < 0.05), suggesting that silencing of GLUT-1 inhibited tumor formation and growth of osteosarcoma cells in vivo. Our findings suggest that the lentiviral-mediated siRNA interference against GLUT-1 may be a valuable tool for gene therapy for osteosarcoma.

Propranolol treatment in life-threatening airway hemangiomas: a case series and review of literature.

OBJECTIVES: Infantile hemangiomas (IHs) in the airway may be potentially life-threatening during the proliferative phase. Available treatments like oral corticosteroids (OCS) and chemotherapeutic agents usually showed variable responses and serious side effects. Propranolol is a new and promising treatment option. METHODS: A case series of five IH patients with airway involvement is presented, supplemented with a review of literature. Propranolol treatment (2.0-3.0mg/kg/day) was initiated between 3 weeks and 6 months of age. Three cases were treated with propranolol monotherapy, 2 cases with OCS primarily and propranolol secondarily, in which treatment with OCS could be reduced rapidly. RESULTS: In our case series a dramatic, fast response was observed in all cases, with a permanent effect after discontinuation in four cases. In one patient a relapse of airway problems occurred two months after discontinuation of propranolol at 16 months of age; this resolved after re-start of propranolol. Review of literature together with these five cases showed 81 patients with airway IHs treated with propranolol. Propranolol was effective in 90% of the cases and seven patients were classified as non-responders. Eight IHs relapsed while weaning of propranolol or after discontinuation; dose adjustment or restart was effective in most cases but one patient appeared resistant to therapy. CONCLUSIONS: Propranolol seems to be a rapidly effective and safe treatment strategy for most IHs obstructing the airway. Because of the fast and important effects of propranolol, randomized controlled trials are hardly justifiable for this specific, relatively rare but, acute treatment indication. Despite the efficacy of propranolol, close monitoring of the patients with an airway IH is required, considering the risk of relapse of symptoms during or after treatment and the reported resistance to propranolol in at least 9% of the published cases. The dose and duration of treatment should be high and long enough to prevent relapse. Further research should focus on the optimal treatment protocol; the actual percentage of non-responders and also the mechanism of resistance to propranolol is unknown and needs to be illuminated.

Regulation of glucose transporter protein-1 and vascular endothelial growth factor by hypoxia inducible factor 1α under hypoxic conditions in Hep-2 human cells.

The present study evaluated the regulation of glucose transporter protein-1 (Glut-1) and vascular endothelial growth factor (VEGF) by hypoxia inducible factor 1α (HIF-1α) under hypoxic conditions in Hep-2 human cells to explore the feasibility of these three genes as tumor markers. Hep-2 cells were cultured under hypoxic and normoxic conditions for 6, 12, 24, 36 and 48 h. The proliferation of Hep-2 cells was evaluated using an MTT assay. The protein and mRNA expression levels of HIF-1α, Glut-1 and VEGF were detected using the S-P immunocytochemical method, western blotting and reverse transcription polymerase chain reaction (RT-PCR). The results revealed that the expression levels of HIF-1α, Glut-1 and VEGF protein in Hep-2 cells were significantly elevated under hypoxic conditions compared with those under normoxic conditions over 36 h. Under hypoxic conditions, mRNA levels of HIF-1α were stable, while mRNA levels of Glut-1 and VEGF changed over time. In conclusion, Glut-1 and VEGF were upregulated by HIF-1α under hypoxic conditions in a time-dependent manner in Hep-2 cells and their co-expression serves as a tumor marker.