Could GLUT12 be a Potential Therapeutic Target in Cancer Treatment? A Preliminary Report.

Background: Recent studies proposed GLUT12 to be a major glucose transporter involved in the glycolytic metabolism of cancer cells.

Methods: GLUT12 expression was determined by immunohistochemistry in a selection of cancer cell lines and a tumour spheroid model.

Results: GLUT12 expression was high in A549 and RH-36; low in HT29; and absent in NB-EB cancer cell lines.

Role of carbohydrate response element-binding protein (ChREBP) in generating an aerobic metabolic phenotype and in breast cancer progression.

Background: The lipogenic transcription factor carbohydrate response element-binding protein (ChREBP) may play a key role in malignant progression of breast cancer by allowing metabolic adaptations to take place in response to changes in oxygenation.

Methods: Immunohistochemical analysis of ChREBP was carried out in human breast tumour tissue microarrays representative of malignant progression from normal breast through to metastatic cancer. The ChREBP protein and mRNA expressions were then analysed in a series of breast cancers for correlative analysis with common and breast-specific hypoxia signatures, and survival.

Adaptation to HIF-1 deficiency by upregulation of the AMP/ATP ratio and phosphofructokinase activation in hepatomas.

Background: HIF-1 deficiency has marked effects on tumour glycolysis and growth. We therefore investigated the consequences of HIF-1 deficiency in mice, using the well established Hepa-1 wild-type (WT) and HIF-1β-deficient (c4) model. These mechanisms could be clinically relevant, since HIF-1 is now a therapeutic target.

Glucose transporter Glut-1 is detectable in peri-necrotic regions in many human tumor types but not normal tissues: Study using tissue microarrays.

The hypoxic tumor microenvironment is associated with malignant progression and poor treatment response. The glucose transporter Glut-1 is a prognostic factor and putative hypoxia marker. So far, studies of Glut-1 in cancer have utilized conventional immunohistochemical analysis in a series of individual biopsy or surgical specimens.

No relationship between 18F-fluorodeoxyglucose positron emission tomography and expression of Glut-1 and -3 and hexokinase I and II in high-grade glioma.

The purpose of this study was to compare glucose metabolism, measured using 18F-fluorodeoxyglucose positron emission tomography ([18F]FDG-PET), with the expression of Glut-1 and -3 and hexokinase I (Hex I) and II in high-grade glioma. The retrospective study involved 27 patients with WHO classification grade III and IV glioma, with either newly diagnosed or recurrent tumours. Patients underwent dynamic and static [18F]FDG-PET to glucose metabolic rate (MRGlu) and standardised uptake value (SUV), respectively.

Hypoxic regulation of glucose transport, anaerobic metabolism and angiogenesis in cancer: novel pathways and targets for anticancer therapeutics.

Cancer cells require a steady source of metabolic energy in order to continue their uncontrolled growth and proliferation. Accelerated glycolysis is one of the biochemical characteristics of cancer cells. Recent work indicates that glucose transport and metabolism are essential for the posttreatment survival of tumor cells, leading to poor prognosis.

Glut-1 as a therapeutic target: increased chemoresistance and HIF-1-independent link with cell turnover is revealed through COMPARE analysis and metabolomic studies.

The facilitative glucose transporter Glut-1 is overexpressed and confers poor prognosis in a wide range of solid tumours. The peri-necrotic pattern of expression often seen in human tumour samples is linked with its transcriptional control in hypoxic conditions by hypoxia-inducible factor HIF-1 or through a reduced rate of oxidative phosphorylation. Hypoxia-regulated genes offer promise as novel therapeutic targets as a means of preventing the proliferation and eventual metastatic spread of tissue originating from residual chemically and radio resistant hypoxic cells that have survived treatment.

Hypoxia-regulated glucose transporter Glut-1 may influence chemosensitivity to some alkylating agents: results of EORTC (First Translational Award) study of the relevance of tumour hypoxia to the outcome of chemotherapy in human tumour-derived xenografts.

Tumour hypoxia confers poor prognosis in a wide range of solid tumours, due to an increased malignancy, increased likelihood of metastasis and treatment resistance. Poorly oxygenated tumours are resistant to both radiation therapy and chemotherapy. However, although the link between radiation therapy and hypoxia is well established in a range of clinical studies, evidence of its influence on chemotherapy response is lacking.

Heterogeneous expression of the aquaporin 1 (AQP1) water channel in tumors of the prostate, breast, ovary, colon and lung: a study using high density multiple human tumor tissue microarrays.

Aquaporin 1 (AQP1) water channels are membrane proteins that control the permeability of endothelial and epithelial barriers by facilitating water movement across cell membranes. Recent studies suggest that AQP1 may be responsible for the high vascular permeability and interstitial fluid pressure in tumors of the brain, colon, breast and pancreas. AQP1 may also play a role in tumor angiogenesis and may be involved in development of effusions or edema fluid.

Prognostic value of facilitative glucose transporter Glut-1 in oral squamous cell carcinomas treated by surgical resection; results of EORTC Translational Research Fund studies.

Hypoxia in tumours of the oral cavity has not been extensively investigated with regard to clinical outcome and prognosis. The expression of the facilitative glucose transporter, Glut-1, has been shown to be related to hypoxia in tumours at other sites. The aim of the present study was to investigate the relationship between Glut-1 expression and clinical outcome in a series of oral squamous cell carcinomas.

Post-genomic applications of tissue microarrays: basic research, prognostic oncology, clinical genomics and drug discovery.

Tissue microarrays (TMAs) are an ordered array of tissue cores on a glass slide. They permit immunohistochemical analysis of numerous tissue sections under identical experimental conditions. The arrays can contain samples of every organ in the human body, or a wide variety of common tumors and obscure clinical cases alongside normal controls.

Viral delivery of P450 reductase recapitulates the ability of constitutive overexpression of reductase enzymes to potentiate the activity of mitomycin C in human breast cancer xenografts.

Indolequinones such as mitomycin C (MMC) require enzymatic bioreduction to yield cytotoxic moieties. An attractive approach to overcome the potential variability in reductive bioactivation between tumors is to exploit specific enzyme-bioreductive drug combinations in an enzyme-directed gene therapy (GDEPT) approach. To this end, human breast cancer cell lines (T47D, MDA468, and MDA231) that overexpress either DT-diaphorase (DTD) or NADPH:cytochrome P450 reductase (P450R) have been developed.

Glucose transporter-1 (GLUT-1): a potential marker of prognosis in rectal carcinoma?

The aim of the study is to evaluate the pattern and level of expression of glucose transporter-1 (GLUT-1) in rectal carcinoma in relation to outcome as a potential surrogate marker of tumour hypoxia. Formalin-fixed tumour sections from 43 patients with rectal carcinoma, who had undergone radical resection with curative intent, were immunohistochemically stained for GLUT-1. A mean of three sections per tumour (range 1-12) were examined.

GLUT-1 and CAIX as intrinsic markers of hypoxia in carcinoma of the cervix: relationship to pimonidazole binding.

The presence of hypoxia in tumours results in the overexpression of certain genes, which are controlled via the transcription factor HIF-1. Hypoxic cells are known to be radioresistant and chemoresistant, thus, a reliable surrogate marker of hypoxia is desirable to ensure that treatment may be rationally applied. Recently, the HIF-1-regulated proteins Glut-1 and CAIX were validated as intrinsic markers of hypoxia by comparison with pO(2) measured using oxygen electrodes.

Oxygen-sensitive enzyme-prodrug gene therapy for the eradication of radiation-resistant solid tumours.

Overwhelming clinical and experimental data demonstrate that tumour hypoxia is associated with aggressive disease and poor treatment outcome as hypoxic cells are refractive to radiotherapy and some forms of chemotherapy. However, hypoxia is rare in physiologically normal tissues representing a tumour-specific condition. To selectively target this therapeutically refractive cell population, we have combined bioreductive chemotherapy with hypoxia-directed gene therapy.

A protective role for HIF-1 in response to redox manipulation and glucose deprivation: implications for tumorigenesis.

We have investigated the role of HIF-1 in the cellular response to redox modulation via the inhibition of oxidative phosphorylation. We demonstrate that manipulation of redox in air, achieved by inhibiting cytochrome oxidase with cyanide, induces HIF-1 mediated transcription in wild-type CHO and HT1080 human tumour cells but not in CHO cells deficient in the oxygen responsive, HIF-1alpha sub-unit of HIF-1. Hypoglycaemia attenuates cyanide-mediated transcription in non-transformed HIF-1 wild-type CHO cells but not the human tumour derived cell line.

Glucose transporter glut-1 expression correlates with tumor hypoxia and predicts metastasis-free survival in advanced carcinoma of the cervix.

Hypoxic tumors are known to be more malignant, to be more likely to metastasize, and to have a poor prognosis. They are also radio- and chemoresistant. For this reason, it is desirable that a clinically useful marker of hypoxia is found, so that treatment with radiotherapy and bioreductive chemotherapy can be rationally applied to individual patients.