chondroitin and Neuroblastoma

Although a number of features distinguish the disease isoform of the prion protein (PrPSc) from its normal cellular counterpart (PrPC) in the transmissible spongiform encephalopathies (TSEs), the neuropathogenesis of these diseases remains an enigma. The amyloid fibrils formed by fragments of human PrP have, however, been shown to be directly neurotoxic in vitro. We show here that sulphated polysaccharides (heparin, keratan and chondroitin) inhibit the neurotoxicity of these amyloid fibrils and this appears to be mediated via inhibition of the polymerization of the PrP peptide into fibrils. This provides a rationale for the therapeutic effects of sulphated polysaccharides and suggests a rapid in vitro functional screen for TSE therapeutics.

Topics: Chondroitin; Glycosaminoglycans; Heparin; Humans; Keratan Sulfate; Neuroblastoma; Peptide Fragments; Prions

Beta-Xylosides stimulate 2- to 6-fold the synthesis of glycosaminoglycans by three types of nonconnective tissue cells (RG-C6, NB41A, and rat hepatoma cells, and normal and simian virus 40 (SV40)-transformed normal human skin fibroblasts. The effect, which is specific for the anomeric linkage and the glycone, is observed in the presence and absence of puromycin. Beta-Xylosides may substitute for xylosylated core protein as initiators of synthesis of chondroitin sulfate chains. No stimulation of synthesis of heparan sulfate was observed. With the use of a fluorogenic xyloside, 4-methylumbelliferyl-beta-D-xyloside, it was demonstrated that the free chondroitin sulfate chains secreted into the medium bear the xyloside at the reducing end, and have an average molecular weight of 16,500.

Topics: Animals; Carcinoma, Hepatocellular; Cells, Cultured; Chondroitin; Chromatography, Gel; Dermatan Sulfate; Fibroblasts; Galactose; Glycosaminoglycans; Glycosides; Heparitin Sulfate; Humans; Hyaluronic Acid; Hymecromone; Liver Neoplasms; Mice; Neuroblastoma; Neuroglia; Nitrophenols; Rats; Simian virus 40; Skin; Spectrometry, Fluorescence; Sulfur Radioisotopes; Sulfuric Acids; Tritium; Xylose

Previous studies have shown that D-xylose partially overcomes the puromycin inhibition of chondroitin sulfate synthesis in cultured chick embryo chondrocytes. Likewise, D-xylose stimulates chondroitin sulfate synthesis by limb bud mesenchyme cells previously treated with BrdU or limb bud cartilage cells treated with puromycin. The studies reported here show that p-nitrophenyl-beta-D-xylopyranoside and 4-methyl-umbelliferyl-beta-D-xylopyranoside cause a much greater stimulation than does D-xylose and are active at much lower concentrations. In contrast to D-xylose, the xylosides strikingly stimulate chondroitin sulfate synthesis in predifferentiated mesenchyme cells. The xylosides stimulate synthesis of chondroitin sulfate by rat glial cell tumor cells (RC-6), a mouse neuroblastoma (C1300, NB41A), and two strains of cultured rat hepatoma cells (HTC, H(4)). These results indicate that certain types of nonconnective tissue cells contain the enzymic machinery for synthesis of chondroitin sulfate which is normally not utilized because of limited synthesis of core protein and/or xylosyltransferase. The beta-xylosides may be used as a probe of the capacity of various cell types to synthesize sulfated glycosaminoglycans.

Topics: Animals; Bromodeoxyuridine; Carcinoma, Hepatocellular; Cartilage; Cell Line; Cells, Cultured; Chick Embryo; Chondroitin; Coumarins; Glioma; Glycosaminoglycans; Glycosides; Liver Neoplasms; Mice; Neuroblastoma; Puromycin; Rats; Stimulation, Chemical; Xylose

In a case of neuroblastoma the presence of an abnormal blood constituent was suspected from the raised erythrocyte sedimentation rate, sludging of the red cells, marked rouleaux formation, an atypical Leishman stain, increased plasma viscosity, and a distorted protein electrophoresis pattern. The abnormal constituent was shown to be a mucopolysaccharide which was either hyaluronic acid or chondroitin sulphate.

Topics: Biopsy; Blood Protein Electrophoresis; Blood Sedimentation; Blood Viscosity; Child, Preschool; Chondroitin; Erythrocytes; Female; Glycosaminoglycans; Humans; Hyaluronic Acid; Liver; Neuroblastoma; Staining and Labeling