Search results for "tumor cell"
showing 10 items of 694 documents
Induction of the fatty acid transport protein 1 and acyl-CoA synthase genes by dimer-selective rexinoids suggests that the peroxisome proliferator-ac…
2000
The intracellular fatty acid content of insulin-sensitive target tissues determines in part their insulin sensitivity. Uptake of fatty acids into cells is a controlled process determined in part by a regulated import/export system that is controlled at least by two key groups of proteins, i.e. the fatty acid transport protein (FATP) and acyl-CoA synthetase (ACS), which facilitate, respectively, the transport of fatty acids across the cell membrane and catalyze their esterification to prevent their efflux. Previously it was shown that the expression of the FATP-1 and ACS genes was controlled by insulin and by peroxisome proliferator-activated receptor (PPAR) agonists in liver or in adipose t…
Glutamine potentiates TNF-α-induced tumor cytotoxicity
2001
L-glutamine (Gln) sensitizes tumor cells to tumor necrosis factor (TNF)-alpha-induced cytotoxicity. The type and mechanism of cell death induced by TNF-alpha was studied in Ehrlich ascites tumor (EAT)-bearing mice fed a Gln-enriched diet (GED; where 30% of the total dietary nitrogen was from Gln). A high rate of Gln oxidation promotes a selective depletion of mitochondrial glutathione (mtGSH) content to approximately 58% of the level found in tumor mitochondria of mice fed a nutritionally complete elemental diet (standard diet, SD). The mechanism of mtGSH depletion involves a glutamate-induced inhibition of GSH transport from the cytosol into mitochondria. The increase in reactive oxygen in…
Visible light (>395nm) causes micronuclei formation in mammalian cells without generation of cyclobutane pyrimidine dimers
2004
Solar radiation gives rise to DNA damage in mammalian cells not only directly by excitation of DNA, which generates predominantly pyrimidine dimers, but also indirectly by the excitation of endogenous photosensitizers, which causes oxidative DNA modifications. The latter mechanism has a low quantum yield, but it is the only one proceeding in the visible range of the spectrum. To investigate its relevance for the genotoxicity of sunlight, we have analysed the generation of micronuclei associated with the induction of oxidative DNA damage by visible light in melanoma cells and primary human skin fibroblasts. Similar yields of light-induced oxidative DNA base modifications sensitive to the rep…
Effect of Chemokine Receptors CXCR4 and CCR7 on the Metastatic Behavior of Human Colorectal Cancer
2005
AbstractPurpose: The expression of chemokine receptors CXCR4 and CCR7 has been associated with tumor dissemination and poor prognosis in a limited number of tumor entities. However, no data are currently available on the impact of chemokine receptor expression on disease progression and prognosis in human colorectal cancer.Experimental Design: The expression of CXCR4 and CCR7 was evaluated in 96 patients with histologically confirmed colorectal cancers and in four colorectal cancer cell lines by immunohistochemical staining. Furthermore, cell migration assays were done with SW480, SW620, and LS174T cancer cells to confirm the effect of the CXCR4 ligand stromal cell–derived factor 1α on migr…
Dissemination of hepatocellular carcinoma is mediated via chemokine receptor CXCR4
2006
In different tumour entities, expression of the chemokine receptor 4 (CXCR4) has been linked to tumour dissemination and poor prognosis. Therefore, we evaluated, if the expression of CXCR4 exerts similar effects in human hepatocellular carcinoma (HCC). Expression analysis and functional assays were performed in vitro to elucidate the impact of CXCL12 on human hepatoma cells lines. In addition, expression of CXCR4 was evaluated in 39 patients with HCC semiquantitatively and correlated with both, tumour and patients characteristics. Human HCC and hepatoma cell lines displayed variable intensities of CXCR4 expression. Loss of p53 function did not impact on CXCR4 expression. Exposure to CXCL12 …
IL-6 receptor independent stimulation of human gp130 by viral IL-6.
2000
Abstract The genome of human herpes virus 8, which is associated with Kaposi’s sarcoma, encodes proteins with similarities to cytokines and chemokines including a homologue of IL-6. Although the function of these viral proteins is unclear, they might have the potential to modulate the immune system. For viral IL-6 (vIL-6), it has been demonstrated that it stimulates IL-6-dependent cells, indicating that the IL-6R system is used. IL-6 binds to IL-6R, and the IL-6/IL-6R complex associates with gp130 which dimerizes and initiates intracellular signaling. Cells that only express gp130 but no IL-6R cannot be stimulated by IL-6 unless a soluble form of the IL-6R is present. This type of signaling…
Cytostatic Activity of Aeroplysinin-1 against Lymphoma and Epithelioma Cells
1989
(±)-Aeroplysinin-1, an optically active 1.2-dihydroarene-1.2-diol. was isolated from the marine sponges Verongia aerophoba (+-isomer) and lanthella ardis (--isomer). For the experiments presented we used the +-isomer from Verongia aerophoba. Here we describe the hitherto unknown biological and pharmacological property of this compound to display pronounced anticancer activity against L5178y mouse lymphoma cells (ED50: 0.5 μm). Friend erythroleukemia cells (ED50: 0.7μm) , human mamma carcinoma cells (ED50: 0.3μm) and human colon carcinoma cells (ED50: 3.0 μm) in vitro. Furthermore, aeroplysinin caused a preferential inhibition of [3H]thymidine (dThd) incorporation rates in L5178y mouse lymph…
Inhibition of the epidermal growth factor receptor tyrosine kinase activity by leflunomide.
1993
AbstractThe active metabolite of leflunomide, A77 1726 inhibits the proliferation of a variety of mammalian cell lines in culture. Epidermal growth factor (EGF)-dependent proliferation is inhibited by A77 1726 at an effective dose of 30–40 μM. A77 1726 appears to directly inhibit the EGF receptor tyrosine-specific kinase activity both in intact cells and purified EGF receptors at the same effective dose. These data suggest that leflunomide inhibits cellular proliferation by the inhibition of tyrosine-specific kinase activities.
Anti-inflammatory effects of cerebrocrast in a model of rat paw edema and on mononuclear THP-1 cells.
2002
Cerebrocrast (IOS 1.1212; 4-[2-(difluoromethoxy)phenyl]-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylic acid di(2-propoxyethyl) diester) is a novel derivative of 1,4-dihydropyridine, which does not antagonize Ca(2+) influx in neuronal tissues. Since several classical dihydropyridines possess anti-inflammatory properties, we first studied the effects of cerebrocrast in a model of rat paw edema induced by carrageenan. Cerebrocrast had a preventative effect in this model of inflammation, with maximal activity (32-45% inhibition) in the 0.1-0.25 mg kg(-1) range. It was ineffective when added after the injection of carrageenan. Subsequent in vitro experiments showed that cerebrocrast in the mi…
Regulation of cell-to-cell communication in non-tumorigenic and malignant human prostate epithelial cells.
2002
BACKGROUND Gap-junction-mediated intercellular communication (GJIC) is required for normal development and tissue homeostasis. However, the role of GJIC in human prostate carcinogenesis and progression remains ill-defined. METHODS The ability of hormones, anti-hormones, and the anti-hypertensive drug, forskolin, to restore GJIC in non-tumorigenic (RWPE-1 and PWR-1E) and malignant (RWPE-2, LNCaP, DU-145) human prostate epithelial cell lines, was examined by Scrape-Loading/Dye Transfer (SL/DT) and Fluorescence Recovery After Photobleaching (FRAP) methods using an Ultima laser cytometer. RESULTS Results from both assays show that PWR-1E, RWPE-2, LNCaP, and DU-145 cells have weak or absent GJIC…