Expression of functional Y1 receptors for neuropeptide Y in human Ewing's sarcoma cell lines.
In the human Ewing's sarcoma cell line WE-68, saturation analysis using 3H-labelled neuropeptide Y ([3H]NPY) as the radioligand disclosed a homogeneous population of binding sites with a dissociation constant (Kd) of 4.5 nM and maximal binding capacity (B(max)) of 712 fmol/mg cell protein. Besides the WE-68 cell line, ten other human Ewing's sarcoma cell lines (FM-62, HS-80, HT-78, HT-M1-78, NT-68, RM-82, RS-63, VH-64, WE-M1-68, WE-M2-68) were also found to display NPY receptors with Kd varying from 3.5 nM to 10.7 nM and B(max) = 247-3744 fmol/mg cell protein. NPY, its natural analogues and the Y1-receptor-specific peptide ligand [Leu31,Pro34]NPY inhibited [3H]NPY binding in the potency order: [Leu31,Pro34]NPY greater than or equal to human NPY greater than or equal to peptide YY (PYY) greater than salmon pancreatic polypeptide (PP) greater than human PP greater than porcine NPY13-36 much greater than NPY22-36. In the Ewing's sarcoma cell lines NPY provoked inhibition of forskolin-stimulated cyclic AMP formation by up to 98%. Pertussis toxin alleviated the cyclic-AMP-inhibitory response to NPY. In isolated Ewing's sarcoma plasma membranes pertussis toxin [32P]ADP-ribosylated a 41-kDa protein. The ability of NPY and analogues to inhibit cyclic AMP accumulation paralleled their potencies in displacing radioligand binding. By contrast, a cell line derived from an atypical form of Ewing's sarcoma did not express specific and functional NPY receptors. These results demonstrate that conventional Ewing's sarcoma cells possess Gi-protein-coupled NPY receptors of the Y1 type, which upon interaction with NPY, PYY, and PP mediate inhibition of cyclic AMP generation.
van Valen
F
F
Abt. für Pädiatrische Hämatologie und Onkologie, Westfälische Wilhelms-Universität, Münster, Federal Republic of Germany.
Winkelmann
W
W
Jürgens
H
H
D000328:Adult; D001667:Binding, Competitive; D002648:Child; D000242:Cyclic AMP / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D009478:Neuropeptide Y / Q000378:metabolism*; D010191:Pancreatic Polypeptide / Q000378:metabolism; D011869:Radioligand Assay; D017476:Receptors, Neuropeptide Y; D017981:Receptors, Neurotransmitter / Q000378:metabolism*; D012512:Sarcoma, Ewing / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D009478:Neuropeptide Y; D017476:Receptors, Neuropeptide Y; D017981:Receptors, Neurotransmitter; D010191:Pancreatic Polypeptide; D000242:Cyclic AMP