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Titolo:
HUMAN LEUKEMIA-CELL LINES BIND BASIC FIBROBLAST GROWTH-FACTOR (FGF) ON FGF RECEPTORS AND HEPARAN SULFATES - DOWN-MODULATION OF FGF RECEPTORS BY PHORBOL ESTER
Autore:
LIUZZO JP; MOSCATELLI D;
Indirizzi:
NYU,MED CTR,DEPT CELL BIOL,550 1ST AVE NEW YORK NY 10016 NYU,MED CTR,DEPT CELL BIOL NEW YORK NY 10016 NYU,MED CTR,KAPLAN COMPREHENS CANC CTR NEW YORK NY 10016
Titolo Testata:
Blood
fascicolo: 1, volume: 87, anno: 1996,
pagine: 245 - 255
SICI:
0006-4971(1996)87:1<245:HLLBBF>2.0.ZU;2-4
Fonte:
ISI
Lingua:
ENG
Soggetto:
HUMAN BONE-MARROW; PLASMINOGEN-ACTIVATOR PRODUCTION; CAPILLARY ENDOTHELIAL-CELLS; HIGH-AFFINITY RECEPTOR; TYROSINE KINASES; MEGAKARYOBLASTIC DIFFERENTIATION; EXTRACELLULAR-MATRIX; SIGNAL TRANSDUCTION; EXPRESSION; LIGAND;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
55
Recensione:
Indirizzi per estratti:
Citazione:
J.P. Liuzzo e D. Moscatelli, "HUMAN LEUKEMIA-CELL LINES BIND BASIC FIBROBLAST GROWTH-FACTOR (FGF) ON FGF RECEPTORS AND HEPARAN SULFATES - DOWN-MODULATION OF FGF RECEPTORS BY PHORBOL ESTER", Blood, 87(1), 1996, pp. 245-255

Abstract

Basic fibroblast growth factor (bFGF) has been identified as an important cytokine for blood cells. To determine whether hematopoietic cells have receptors that recognize bFGF, the ability of human leukemia cell lines to bind I-125-bFGF was investigated. Specific bFGF-binding sites were identified on K562 and HL60 cells, but not on U937 cells. DAMI cells bound low amounts of I-125-bFGF specifically. Binding of I-125-bFGF to K562 cell surfaces was reduced in a dose-dependent manner by unlabeled bFGF or by heparin. Scatchard analysis of binding to K562 cells revealed two classes of binding sites: 1,650 high affinity bindingsites per cell with a dissociation constant (kd) of 192 pmol/L, and 36,600 low affinity sites per cell with a kd of 9.3 nmol/L. Chemical crosslinking experiments with K562, HL60, and DAMI cells revealed receptor-growth factor complexes with molecular masses of 140 to 160 kD, similar in size to complexes formed by known receptor species. Binding ofI-125-bFGF to K562 cells was sensitive to heparinase treatment but not to chondroitinase treatment, suggesting that heparan sulfate proteoglycans (HSPGs) may be responsible for the low affinity binding sites. To further investigate whether K562 cells make HSPG, the incorporationof (SO4)-S-35 into proteoglycans was assessed. Metabolically labeled cell-surface proteoglycans with molecular masses of 180 to 300 kD wereidentified in K562 cells. These proteoglycans were sensitive to heparinase, demonstrating that K562 cells synthesize bFGF-binding HSPG. Treatment of K562 cells with phorbol-12-myristate-13-acetate (PMA) causeda loss of bFGF-binding capacity. This decreased binding capacity reflected a rapid loss of high affinity receptors. The ability to form bFGF-receptor complexes decreased by 65% to 70% within 1 hour and declined continuously thereafter. The decrease in binding of bFGF was not dueto an autocrine downregulation of bFGF receptors, because there was no increase in bFGF after PMA treatment as detected by Western blotting, and suramin, which blocks bFGF binding to receptors, did not preventthe loss of receptors after exposure to PMA. In addition, inhibitors of either protein synthesis or protease activity did not prevent the loss of bFGF receptors in PMA-treated cells. In summary, this work demonstrates that leukemia cell lines have receptors that specifically bind bFGF and supports the hypothesis that bFGF acts directly on certain blood cells to stimulate their proliferation. (C) 1996 by The AmericanSociety of Hematology.

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Documento generato il 05/12/20 alle ore 19:55:55