Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.3.9 (glucose-6-phosphatase)
 3,081 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sarcoma cells exhibit higher rates of glycolysis than normal tissues and may be dependent on glucose utilization for growth. Accordingly, we tested the ability of the glucose antimetabolite 2-deoxy-D-glucose (2-DG) to inhibit the growth of an established methylcholanthrene-induced rat fibrosarcoma in three groups of F344 rats with increasing subcutaneous inoculations of tumor (2 X 10(6) cells, 1 X 10(7) cells, and 1 mm tumor fragments). Rats were randomized to receive 2-DG or saline solution at doses of 0.75 gm/kg, 1.5 gm/kg, or 1.75 gm/kg, beginning 3 days after tumor implantation and continuing for 10 days. Tumors were removed and weighed on day 14. We measured tissue [14C]-2-DG levels in tumor, brain, liver, and muscle after intraperitoneal injection of radiolabeled 2-DG. In these same tissues we determined the activity of glucose-6-phosphatase (G-6-Pase), an enzyme which dephosphorylates the intracellular glycolytic inhibitor 2-DG-6-phosphate, thus reversing the antitumor effect of 2-DG. All groups treated with 2-DG had a significant reduction in tumor weight of 50% to 70% when compared with saline solution-treated controls. Toxicity was substantial at the highest dose of 2-DG, but minimal toxicity was noted at intermediate and low doses. Tumor had the greatest uptake of [14C]-2-DG, with low levels of G-6-Pase leading to prolonged retention and highest tissue levels of radiolabeled 2-DG. Use of 2-DG inhibits established sarcoma growth because it is rapidly transported into tumors, cannot be metabolized after phosphorylation, and is dephosphorylated and released slowly from tumor cells. Rat sarcoma growth is dependent on glucose utilization and can be effectively inhibited by glucose antagonism.
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PMID:Inhibition of established rat fibrosarcoma growth by the glucose antagonist 2-deoxy-D-glucose. 303 79

To elucidate interactions between the glucose transport system and hepatic glucose production in the tumour-bearing state, glycogen storage, expression of glucose transporter isoform 2 (Glut 2) and activities of glucose-6-phosphatase (G-6-Pase) and hexokinase were histochemically examined in hepatocytes of tumour-bearing rats. Five male F344 rats, subcutaneously inoculated with methylcholanthrene (MCA)-induced sarcoma cells were compared with five pair-fed animals and four ad libitum fed controls. Glycogen storage was markedly decreased in liver cells of tumour-bearing rats compared to in those of control animals. Glut 2 immunoreactivity was uniformly seen in the cellular membrane of hepatocytes from control animals. In rats bearing sarcoma, the staining intensity was significantly decreased, suggesting that Glut 2 with its bi-directional transport capacity was down-regulated in the tumour-bearing state. Positive staining for hexokinase activity was located in the perivenous area in livers from control animals and was more diffusely located and more intense in livers from tumour-bearing animals. G-6-Pase activity, limited to the peripheral area in livers from controls, extended to the intermediate area and had stronger reactivity in livers from tumour-bearing animals. In the tumour-bearing cachectic condition, glucose may be partially consumed by a futile cycle, hepatic metabolic zonation was disturbed, and the release of glucose from the liver may not be mediated by a facilitative glucose transporter-2.
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PMID:Alteration in immunoexpression of glucose transporter 2 in liver of tumour-bearing rats. 961 47

Previously, we described that embryonic day 14.5 (E14.5) mouse fetal hepatocytes differentiate to express tyrosine amino transferase (TAT) and glucose-6-phosphatase, which are expressed in the perinatal liver, in response to oncostatin M (OSM) or in high-cell-density culture. However, under such conditions, fetal hepatic cells failed to express genes for adult liver-specific enzymes, such as tryptophan oxygenase (TO). Although phenobarbital (PB) and dimethylsulfoxide (DMSO) have been known to maintain the functions of adult hepatocytes in vitro, they failed to induce TO expression in fetal hepatic cells. Thus far, no system has been developed that reproduces terminal differentiation of fetal hepatocytes in vitro. Here, we describe that extracellular matrices derived from Engelbreth-Holm-Swarm sarcoma (EHS) in combination with OSM or high-cell-density culture induced expression of TO as well as cytochrome P450 genes that are involved in detoxification. However, EHS alone was insufficient to induce expression of TO, although it induced TAT expression in fetal hepatocytes. In addition, high-density culture further augmented differentiation. In conclusion, the combination of signals by cytokines, cell-cell contact, and cell-matrix interaction is required for induction of adult liver functions in fetal hepatocytes in vitro. This primary culture system will be useful for studying the mechanism of liver development.
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PMID:Maturation of fetal hepatocytes in vitro by extracellular matrices and oncostatin M: induction of tryptophan oxygenase. 1202 20

The usefulness of whole-body 18-fluoro-2-deoxyglucose (FDG)-fluorodeoxyglucose positron emission (PET)/computed tomography (CT) is established for assessment of disease staging, detection of early disease recurrence, therapeutic evaluation, and predicting prognosis in various malignancies; and for evaluating the spread of inflammation. However, the role of FDG-PET/CT for the liver is limited because CT and magnetic resonance imaging (MRI) can provide an accurate diagnosis of most tumors. In addition, in other potentially useful roles there are several pitfalls in the interpretation of FDG uptake in PET/CT imaging. Accurate evaluation demands knowledge of the FDG uptake of each lesion, including potential negative and positive uptakes, and requires an understanding of the underlying background of the molecular mechanisms. The degree of FDG uptake is dependent on cellular metabolic rate and the expression of glucose transporter, hexokinase, and glucose-6-phosphatase, which in turn are closely affected by biological characteristics such as pathological category (e.g., adenocarcinoma, squamous cell carcinoma, small cell cancer, transitional cell cancer, neuroendocrine tumor, sarcoma, lymphoma), tumor differentiation, histological behavior (e.g., solid, cystic, mucinous), and intratumoral alterations (e.g., necrosis, degeneration, hemorrhage). Correlation with the CT and MRI findings, which also precisely depict the pathological findings, is important to avoid misdiagnosis.
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PMID:FDG-PET/CT imaging findings of hepatic tumors and tumor-like lesions based on molecular background. 3224 50