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Query: UMLS:C0025202 (melanoma)
 69,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Here we describe a two-step procedure for purification of human tenascin from conditioned medium of the SK-MEL-28 human melanoma cell line. The first step consists in passing the conditioned media through two chromatography columns connected in sequence. The first is a large capacity gelatin--Sepharose affinity chromatography column (to remove fibronectin), the second, over which the unbound material from the first column flows directly, is a hydroxyapatite chromatography column. Under these conditions, all tenascin present in the conditioned medium binds to the hydroxyapatite chromatography column from which it is then eluted by a 5-300 mM sodium phosphate gradient. With this step, we obtain a crude tenascin preparation, concentrated about 20 times with respect to the starting conditioned medium, and in which tenascin represents more than 50% of the total protein. The second step consists of two sequential precipitations with 6% and 12.8% poly(ethylene glycol). After this step, tenascin is more than 95% pure and does not show any contamination of chondroitin-sulfate-containing proteoglycans that are known to bind to it. From 21 medium we obtain about 3-4 mg tenascin which corresponds to a yield of about 40-50%. This procedure gives a higher yield, is simpler with respect to procedures previously described, avoids the exposure of the protein to denaturing agents or harsh conditions and could be used for purification of tenascin from the conditioned media of other cell lines. Thus, this procedure may represent a simple and useful tool for the preparation of tenascin to study its biological functions.
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PMID:A simple procedure for tenascin purification. 137 29

Aberrant signal transduction has been implicated in malignant transformation, growth, and progression. This has led to the proposal to use inhibitors of signal transduction pathways to treat cancer. One approach to circumventing potential toxicity and improving efficacy would be to target pathways upon which cancer cells selectively depend. Pathways associated with the malignant process involve calcium fluxes, the release of arachidonic acid, and the generation of phosphoinositides. In this report, CAI (L651582, NSC 609974), a substituted carboxyamido-imidazole and novel inhibitor of these selected signal transduction pathways, inhibits anchorage-dependent and -independent growth in a large series of human cancer cell lines. CAI pretreatment of HT-29 human colon cancer and 5R ras-transfected rat embryo fibroblast cells inhibits the formation and growth of experimental pulmonary metastases in nude mice. Oral administration of CAI in PEG-400 vehicle arrests growth and metastasis of transplanted human melanoma and ovarian cancer xenografts. No significant gross or histological toxicity was observed at CAI doses yielding blood levels in the concentration range demonstrated to inhibit select signal transduction pathways in vitro. These data indicate the feasibility and demonstrate a potential selectivity and sensitivity of using specific signal transduction inhibitors for the experimental treatment of cancer.
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PMID:In vivo efficacy of a novel inhibitor of selected signal transduction pathways including calcium, arachidonate, and inositol phosphates. 159 30

Hybrids of a fibronectin-related tripeptide (Arg-Gly-Asp) and amino-poly(ethylene glycol) were prepared and their inhibitory effect on experimental metastasis in mice was examined. The hybrids exhibited a potent inhibitory effect on the metastasis of B16 melanoma BL6.
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PMID:Preparation of [Arg-Gly-Asp]-[amino-poly(ethylene glycol)] hybrids and their inhibitory effect on experimental metastasis. 181 33

Inhibitory effects of synthetic laminin related peptides on experimental metastasis formation in mice were examined. Of the synthetic peptides, YIGSRG-[amino-poly(ethylene glycol)] hybrid exhibited the most potent inhibitory effect on the metastasis of B16 melanoma BL6.
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PMID:Amino acids and peptides. XIV. Laminin related peptides and their inhibitory effect on experimental metastasis formation. 199 83

When mixed in aqueous solution at low concentrations, the neutral polymers dextran and poly(ethylene glycol) (PEG) rapidly form a two-phase system, consisting of a dextran-enriched lower phase and a PEG-enriched upper phase. Two B16 mouse melanoma cell lines, B16-F1 (low lung colonizing capability) and B16-F10 (high lung colonizing capability) were found to partition differentially into the upper phase in a variety of two-phase systems. Upper-phase partition depends primarily on either hydrophilic (i.e., surface charge density) or hydrophobic (i.e., affinity for the hydrocarbon chain of a PEG-fatty acid ester) cell surface properties, depending on the system used. In single-step partition studies, cells of the B16-F10 subline displayed a greater preference than B16-F1 cells for the upper phase in the hydrophilic system and less preference in systems sensitive to hydrophobic properties. Countercurrent distribution (CCD) experiments, performed with [125I]deoxyuridine DNA-labelled cells, were consistent with single-step partition results. These CCD results demonstrated that B16-F10 cells exhibited greater DNA synthesis than B16-F1 cells and that considerable heterogeneity, in both hydrophobic and hydrophilic surface properties, was present in subpopulations of cells of both sublines. The data also showed considerable enrichment of 125I-specific cell activity in certain sections of the distributions, indicating that differences in cellular DNA synthesis are reflected in the surface properties to which partition is sensitive.
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PMID:Heterogeneity in the surface properties of B16 melanoma cells from sublines with differing metastatic potential detected via two-polymer aqueous-phase partition. 242 47

The recombinant lymphokine interleukin-2 (IL-2) has activity in renal cell carcinoma, melanoma, and other cancers. A side effect of IL-2 use is a "capillary leak phenomenon" which is purported to be related to endothelial effects of IL-2 itself or to cells activated by IL-2. We studied IL-2 effects on rat lung lavage parameters to determine whether endothelial damage occurred. The specific endpoints were 125I-albumin extravasation, lavage protein, and lavage angiotensin-converting enzyme (ACE) activity. To ensure sensitivity of these endpoints, we used the known endothelial toxicant thiourea, which increases lung lavage protein and lavage ACE. We found that both PEG IL-2 and thiourea increased the amount of protein and 125-I flux into the lavage. However, although thiourea increased lavage ACE, PEG IL-2 did not. These results suggest that PEG IL-2 can increase protein and iodine flux across the endothelium without causing cell injury.
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PMID:Effects of PEG-coupled interleukin-2 on rat lung lavage parameters. 256 75

B16 mouse melanoma cells in monolayers may be satisfactorily fused with 50% PEG 1500. However, pre-treatment with detergents in solution at low concentrations significantly increases PEG fusion, up to 8-fold in some instances, without impairing cell viability. The practical and mechanistical implications of this finding are discussed.
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PMID:Surfactant enhancement of polyethyleneglycol-induced cell fusion. 259 1

Modification of recombinant human interleukin 2 (rhIL-2) with monomethoxy polyethylene glycol has been shown to alter its pharmacokinetic properties. Therefore, we investigated the pharmacological parameters of schedule and dose in order to assess the impact on the in vivo antitumor activity of this modification. The antitumor efficacy, as well as the toxicity, of polyethylene glycol-interleukin 2 (PEG-IL-2) was compared to that of rhIL-2 in three transplantable syngeneic murine tumor models, Meth A fibrosarcoma, B16 melanoma, and Pan-02 pancreatic carcinoma. At equitoxic dose levels, the antitumor activity of PEG-IL-2 was far superior to that of rhIL-2 in all three tumor models. This efficacy of PEG-IL-2 was dose dependent and was greatest on a Q7D x 2 schedule in Meth A and B16. When the same total doses were further divided and delivered on any of several alternative schedules, either the efficacy was reduced or the toxicity of the treatments was increased. In Pan-02, a rhIL-2-resistant tumor, PEG-IL-2 treatment on either the Q7D x 2, Q4D x 3, or Q3D x 4 schedule resulted in approximately a 200% increase in lifespan; however, the toxicity of the treatment increased as the interval between doses was shortened. Simulations of the pharmacokinetic profiles of these various regimens suggested that the toxicity of PEG-IL-2 and rhIL-2 was related to the minimum plasma concentration that was obtained and the time interval between peak levels. The efficacy of the treatment was associated with the interleukin 2 plasma peak height, since a dose response was observed; however, peak plasma concentration did not appear to be the only parameter which determined efficacy. We hypothesize that this observed schedule dependence is also affected by the kinetics of the host's biological response to rhIL-2.
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PMID:Schedule dependency of the antitumor activity and toxicity of polyethylene glycol-modified interleukin 2 in murine tumor models. 281 8

Human intraspecific hybrids were formed between tumor cells isolated from both primary and metastatic tumors and a tissue culture adapted cell line, D98OR, a HeLa derivative which is thioguanine and ouabain resistant. Five different tumor types in all were attempted: renal cell carcinoma, colon adenocarcinoma, melanoma, chrondrosarcoma, and hepatocarcinoma. The tumor tissue was either (1) immediately dissociated and fused, or (2) frozen and later thawed, dissociated, and fused. Two different PEG concentrations were used. The results reported here demonstrate that: (1) hybrid tumor cell lines can be made from several types of cancer, (2) unfrozen tumor tissue fused with D98OR by exposure to 50% PEG appears optimal, (3) chromosome loss, as determined by flow cytometry studies of hybrid DNA content, is minimal, and (4) hybrids have characteristics consistent with derivation from tumor cells rather than derivation from the nonmalignant cells of a tumor.
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PMID:Somatic cell hybridization of human tumor samples. 658 90

The various manipulations involved in the isolation of membrane fragments from culture fluids of murine melanoma cells were examined to discern their effect on membrane fragment structure. Ultracentrifugation and gel chromatography were compared using the presence of marker enzymes and the sensitivity to a non-ionic detergent (Triton X-100). Fractionation of media by gel chromatography resulted in only one major form of membrane particles, while ultracentrifugation, followed by resuspension, produced at least two major populations from the identical material. These results indicate that the optimal procedure for membrane fragment isolation is fractionation by an agarose-containing gel, followed by concentration using PEG 20,000.
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PMID:Isolation of plasma membrane fragments from cultured murine melanoma cells. 687 Aug 70


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