Renal cell carcinoma and oxidative stress: The lack of peroxisomes.

Oxidative stress plays an important role in carcinogenesis because of induction of DNA damage and its effects on intracellular signal transduction pathways. Here, we investigated the relationship between the defence against oxidative stress and human renal cell carcinoma that originates from proximal tubular epithelium. Oxygen insensitivity of the histochemical assay of glucose-6-phosphate dehydrogenase (G6PD) activity is a diagnostic tool for the detection of carcinomas.

Modulation of pentose phosphate pathway during cell cycle progression in human colon adenocarcinoma cell line HT29.

Cell cycle regulation is dependent on multiple cellular and molecular events. Cell proliferation requires metabolic sources for the duplication of DNA and cell size. However, nucleotide reservoirs are not sufficient to support cell duplication and, therefore, biosynthetic pathways should be upregulated during cell cycle.

Noninvasive magnetic resonance imaging of the development of individual colon cancer tumors in rat liver.

Monitoring tumor development is essential for the understanding of mechanisms involved in tumor progression and to determine efficacy of therapy. One of the evolving approaches is longitudinal noninvasive magnetic resonance imaging (MRI) of tumors in experimental models. We applied high-resolution MRI at 7 Tesla to study the development of colon cancer tumors in rat liver.

Elevated activity of the oxidative and non-oxidative pentose phosphate pathway in (pre)neoplastic lesions in rat liver.

(Pre)neoplastic lesions in livers of rats induced by diethylnitrosamine are characterized by elevated activity of the first irreversible enzyme of the oxidative branch of the pentose phosphate pathway (PPP), glucose-6-phosphate dehydrogenase (G6PD), for production of NADPH. In the present study, the activity of G6PD, and the other NADPH-producing enzymes, phosphogluconate dehydrogenase (PGD), isocitrate dehydrogenase (ICD) and malate dehydrogenase (MD) was investigated in (pre)neoplastic lesions by metabolic mapping. Transketolase (TKT), the reversible rate-limiting enzyme of the non-oxidative branch of the PPP, mainly responsible for ribose production, was studied as well.

Metastasis is promoted by a bioenergetic switch: new targets for progressive renal cell cancer.

Targeted therapies have demonstrated clinical benefit with limited impact on long-term disease specific survival in the treatment of renal cell cancer (RCC). New opportunities for the treatment of tumors that are resistant or have relapsed, are needed. Increased anaerobic glucose fermentation to lactate (aerobic glycolysis), leading to oxygen- and mitochondria-independent ATP generation is a hallmark of aggressive cancer growth.

NADPH production by the pentose phosphate pathway in the zona fasciculata of rat adrenal gland.

Biosynthesis of steroid hormones in the cortex of the adrenal gland takes place in smooth endoplasmic reticulum and mitochondria and requires NADPH. Four enzymes produce NADPH: glucose-6-phosphate dehydrogenase (G6PD), the key regulatory enzyme of the pentose phosphate pathway, phosphogluconate dehydrogenase (PGD), the third enzyme of that pathway, malate dehydrogenase (MDH), and isocitrate dehydrogenase (ICDH). However, the contribution of each enzyme to NADPH production in the cortex of adrenal gland has not been established.

Loss of peroxisomes causes oxygen insensitivity of the histochemical assay of glucose-6-phosphate dehydrogenase activity to detect cancer cells.

Oxygen insensitivity of carcinoma cells and oxygen sensitivity of non-cancer cells in the histochemical assay of glucose-6-phosphate dehydrogenase (G6PD) enables detection of carcinoma cells in unfixed cell smears or cryostat sections of biopsies. The metabolic background of oxygen insensitivity is still not understood completely. In the present study, rat hepatocytes, rat hepatoma cells (FTO-2B), and human colon carcinoma cells (HT29) were used to elucidate these backgrounds.

Tissue-type plasminogen activator modulates inflammatory responses and renal function in ischemia reperfusion injury.

Acute renal failure is often the result of ischemia-reperfusion (I/R) injury. Neutrophil influx is an important damaging event in I/R. Tissue-type plasminogen activator (tPA) not only is a major fibrinolytic agent but also is involved in inflammatory processes.

In situ localization of transketolase activity in epithelial cells of different rat tissues and subcellularly in liver parenchymal cells.

Metabolic mapping of enzyme activities (enzyme histochemistry) is an important tool to understand (patho)physiological functions of enzymes. A new enzyme histochemical method has been developed to detect transketolase activity in situ in various rat tissues and its ultrastructural localization in individual cells. In situ detection of transketolase is important because this multifunctional enzyme has been related with diseases such as cancer, diabetes, Alzheimer's disease, and Wernicke-Korsakoff's syndrome.

Improved localization of glucose-6-phosphate dehydrogenase activity in cells with 5-cyano-2,3-ditolyl-tetrazolium chloride as fluorescent redox dye reveals its cell cycle-dependent regulation.

Since the introduction of cyano-ditolyl-tetrazolium chloride (CTC), a tetrazolium salt that gives rise to a fluorescent formazan after reduction, it has been applied to quantify activity of dehydrogenases in individual cells using flow cytometry. Confocal laser scanning microscopy (CLSM) showed that the fluorescent formazan was exclusively localized at the surface of individual cells and not at intracellular sites of enzyme activity. In the present study, the technique has been optimized to localize activity of glucose-6-phosphate dehydrogenase (G6PD) intracellularly in individual cells.

The role of gelatinases in colorectal cancer progression and metastasis.

Various proteases are involved in cancer progression and metastasis. In particular, gelatinases, matrix metalloproteinase-2 (MMP-2) and MMP-9, have been implicated to play a role in colon cancer progression and metastasis in animal models and patients. In the present review, the clinical relevance and the prognostic value of messenger ribonucleic acid (mRNA) and protein expression and proenzyme activation of MMP-2 and MMP-9 are evaluated in relation to colorectal cancer.

Kupffer cells and not liver sinusoidal endothelial cells prevent lentiviral transduction of hepatocytes.

Lentiviral vectors can stably transduce dividing and nondividing cells in vivo and are best suited to long-term correction of inherited liver diseases. Intraportal administration of lentiviral vectors expressing green fluorescent protein (Lenti-GFP) in mice resulted in a higher transduction of nonparenchymal cells than hepatocytes (7.32 +/- 3.

Metabolic mapping of proteinase activity with emphasis on in situ zymography of gelatinases: review and protocols.

Proteases are essential for protein catabolism, regulation of a wide range of biological processes, and in the pathogenesis of many diseases. Several techniques are available to localize activity of proteases in tissue sections or cell preparations. For localization of the activity of matrix metalloproteinases, in situ zymography was introduced some decades ago.

Visualization of early events in tumor formation of eGFP-transfected rat colon cancer cells in liver.

Colon cancer preferentially metastasizes to the liver. To determine cellular backgrounds of this preference, we generated an enhanced green fluorescent protein (eGFP)-expressing rat adenocarcinoma cell line (CC531s) that forms metastases in rat liver after administration to the portal vein. Intravital videomicroscopy (IVVM) was used to visualize early events in the development of tumors in livers of live animals from the time of injection of the cancer cells up to 4 days afterward.

In situ localization of gelatinolytic activity in the extracellular matrix of metastases of colon cancer in rat liver using quenched fluorogenic DQ-gelatin.

Matrix metalloproteinases (MMPs) such as gelatinases are believed to play an important role in invasion and metastasis of cancer. In this study we investigated the possible role of MMP-2 and MMP-9 in an experimental model of colon cancer metastasis in rat liver. We demonstrated with gelatin zymography that the tumors contained MMP-2 and MMP-9, but only MMP-2 was present in the active form.

Electron microscopical enzyme histochemistry on unfixed tissues and cells. Bridging the gap between LM and EM enzyme histochemistry.

In principle, enzyme histochemistry should be performed on unfixed tissues and cells to avoid inhibition of enzyme activity by chemical fixation. For EM enzyme histochemistry, unfixed tissue specimens include fresh tissue blocks, non-frozen tissue chopper sections, cryostat sections and cell preparations. Studies on localization of enzyme activity at the ultrastructural level in unfixed specimens, be it fresh or frozen, are reviewed here.

Post-translational regulation of glucose-6-phosphate dehydrogenase activity in (pre)neoplastic lesions in rat liver.

Glucose-6-phosphate dehydrogenase (G6PD; EC 1.1.1.

Metabolic control analysis aimed at the ribose synthesis pathways of tumor cells: a new strategy for antitumor drug development.

Metabolic control analysis predicts that effects on tumor growth are likely to be obtained with lower concentrations of drug, if an enzyme with a high control coefficient on tumor growth is being inhibited. Here we measure glucose-6-phosphate dehydrogenase (G6PDH) control coefficient on in vivo tumor growth using mice bearing Ehrlich ascites tumor cells. We used dehydroepiandrosterone-sulphate (DHEA-S), an uncompetitive inhibitor of this enzyme and the in situ cytochemical method to measure the enzyme activity changes that accompany changes on tumor cell growth.

Ultrastructural localization of xanthine oxidoreductase activity in isolated rat liver cells.

Xanthine oxidoreductase (XOR) can exist in a dehydrogenase form (XD) and an oxidase form (XO). The D-form uses NAD as cofactor and the O-form uses oxygen as second substrate and produces oxygen radicals. Both enzymes have a high affinity for hypoxanthine and xanthine as substrate and produce uric acid, a potent antioxidant.