Characterization of cell-surface glycopeptides from mouse cerebral cortex that inhibit cell growth and protein synthesis

Abstract

Glycopeptides were isolated from the cell surfaces of mouse brain cortical tissue that inhibited both cell division and protein synthesis by cells in culture. The protein-synthesis inhibition appeared to affect most cells exposed and was equally effective against glycoprotein and protein synthesis. The inhibition of protein metabolism was independent of mRNA synthesis and uptake of labelled precursors into intracellular pools, indicating that it was directed at intracellular translational events. Fractionation of chloroform/methanol-extracted preparations of this brain cell-surface substance on Bio-Gel P-100 revealed the material to be quite heterogenous, although inhibitory activity was found only in fractions of mol.wt. 25000--30000 and 6000--10000. Biochemical analysis of these fractions demonstrated that they were 6% carbohydrate and 94% amino acid by weight. The 25000--30000-mol.wt. glycopeptides were shown to inhibit cell growth at concentrations of 2 microgram/ml in cultured cells and to inhibit protein synthesis by 50% at concentrations of 3 microgram/ml. The 25000--30000-mol.wt. brain-cell-surface-substance glycopeptides were further purified by ultrafiltration and affinity chromatography with Ulex europaeus agglutinin, resulting in a 400-fold increase in specific biological activity. The inhibitor was not lethal to cells and was not species- or tissue-specific.

Density dependent regulation of human Schwann cell proliferation

“…Confluent cultures of human diploid cells show a strongly reduced proliferation rate compared to sparsely seeded cells (Augenlicht and Baserga, 1974;Bard and Elsdale, 1986) and the addition of isolated plasma membranes, or membrane proteins reduce growth rate in a concentration-dependent fashion (Natraj and Datta, 1978;Kinders et al, 1980;Raben et al, 1981;Nilsson et al, 1983;Yaoi, 1984;Fritze et al, 1985;Heimark and Schwartz, 1985;Pereira-Smith et al, 1985;Wieser et al, 1985;Stein and Alkins, 1986;Oesch, 1986, 1987). Wieser et al (1990) reported evidence that a 60 -70 kDa plasma membrane glycoprotein, contactinhibin (CI), is responsible for the density-dependent growth inhibition of normal human diploid fibroblasts.…”

Growth control in cultured 3T3 fibroblasts: neutralization and identification of a growth-inhibitory factor by a monoclonal antibody.

“…4, compo In addition, it would be of obvious interest to establish the relationship between the Mr 13,000 polypeptide in FGR-s and similar growth-inhibitory activities reported in other systems. These include (i) the membrane-bound growth-inhibitory activities of 3T3 cells reported by Glaser (13,14), Peterson (15,16), and Datta (17,18) and their co-workers; (ii) the highly purified growth-inhibitory factor from medium of BSC-1 cells (19,20); (iii) the hepatic proliferation inhibitor (Mr, 26,000; pI, 4.65) isolated from normal rat livers (21,22); and (iv) the growth-inhibitory glycopeptides identified and partially purified from mouse and bovine cerebral cortex cells (23,24). More recently, it has been shown that secondary cultures of mouse embryo fibroblasts release into the medium a growth-inhibitory activity whose physicochemical behavior closely parallels that of FGR-s (25) and that a growth inhibitor for Ehrlich ascites mammary carcinoma cells can be isolated from the bovine mammary gland (26).…”

Receptor occupancy by a bovine sialoglycopeptide inhibitor correlates with inhibition of protein synthesis

“…We have been interested in understanding the mechanisms of density-dependent regulation of cell growth for several years (Kinders et al, 1980;Kinders and Johnson, 1982;Johnson et al, 1985). We recently purified a 18,000 dalton sialoglycopeptide (PI 3.0) that inhibits protein synthesis and DNA synthesis of non-transformed but not transformed cells while not afl'ecting uptake of radiolabeled precursors (Sharifi et al, 1986a;Sharifi et al, 1986b).…”