Presence of dopamine D-2 receptors in human tumoral cell lines.
[125I] Iodosulpride binding was examined on eight human cell lines derived from lung, breast and digestive tract carcinomas, neuroblastomas and leukemia. Specific binding was detected in five of these cell lines. In the richest cell line N417, derived from small cell lung carcinoma, [125I] iodosulpride bound with a high affinity (Kd = 1.3 nM) to an apparently homogeneous population of binding site (Bmax = 1,606 sites per cell). These sites displayed a typical D-2 specificity, established with several dopaminergic agonists and antagonists selective of either D-1 or D-2 receptor subtypes. In addition, dopamine, apomorphine and RU 24926 distinguished high- and low-affinity sites, suggesting that the binding sites are associated with a G-protein. The biological significance and the possible diagnostic implication of the presence of D-2 receptors on these cell lines are discussed.
Sokoloff
P
P
Unité de Neurobiologie et Pharmacologie (U. 109) de l'INSERM, Centre Paul Broca, Paris, France.
Riou
J F
JF
Martres
M P
MP
Schwartz
J C
JC
D001058:Apomorphine / Q000378:metabolism; D001943:Breast Neoplasms / Q000032:analysis; D002462:Cell Membrane / Q000032:analysis; D004067:Digestive System Neoplasms / Q000032:analysis; D004298:Dopamine / Q000378:metabolism; D006801:Humans; D007457:Iodine Radioisotopes; D007938:Leukemia / Q000378:metabolism; D008175:Lung Neoplasms / Q000032:analysis; D009369:Neoplasms / Q000032:analysis*; D009447:Neuroblastoma / Q000032:analysis; D010627:Phenethylamines / Q000378:metabolism; D011954:Receptors, Dopamine / Q000032:analysis* / Q000378:metabolism; D017448:Receptors, Dopamine D2; D013469:Sulpiride / Q000031:analogs & derivatives / Q000378:metabolism; D014407:Tumor Cells, Cultured
D007457:Iodine Radioisotopes; D010627:Phenethylamines; D011954:Receptors, Dopamine; D017448:Receptors, Dopamine D2; C045105:iodosulpride; C025254:RU 24926; D013469:Sulpiride; D001058:Apomorphine; D004298:Dopamine