Characterization, in some human breast cancer cell lines, of gastrin-releasing peptide-like receptors which are absent in normal breast epithelial cells.
The binding of 125I-Tyr4 bombesin was investigated on plasma membranes of 8 human breast cancer cell lines and 2 long-term cultures of normal human breast epithelial cells. Scatchard plots were compatible with high-affinity, single-site class of receptors in 3 cell lines (KD of 0.75 x 10(-9) and 10(-9) M, Bmax of 0.75 x 10(-13) and 9.7 x 10(-13) M/mg protein in MDA-MB231 and in T47D cells, respectively) while no binding was observed in 5 other cell lines and normal epithelial cells. The neuropeptide and its structural analogues (natural or synthetic) inhibited the binding of 125I-Tyr4 bombesin in the following order of potency: gastrin-releasing peptide (GRP, EC50 = 1.7 x 10(-10) M) greater than BIM 26159 greater than bombesin, Tyr4 bombesin greater than BIM 26147 greater than litorin greater than neuromedin C. In contrast, 125I-Tyr4 bombesin binding was not displaced by neuromedin B, somatostatin, bradykinin and insulin. In agreement with our binding data, SDS-PAGE of the complex 125I-Tyr4 bombesin-receptor covalently linked by ethylene glycol-bis succinimidyl succinate (EGS) identified after autoradiography a single band with a molecular weight of 75,000, which disappeared in the presence of bombesin in excess. No transcription of either GRP or neuromedin B mRNA could be shown in tumor or normal cells. Exogenous gastrin-releasing peptide had no effect on growth of the cell lines when a serum-free medium was used, implicating that in breast cancer cell lines this receptor does not mediate growth but has a functional role.
Giacchetti
S
S
Laboratory of Pharmacology, Hopital Saint-Louis, Paris, France.
Gauvillé
C
C
de Crémoux
P
P
Bertin
L
L
Berthon
P
P
Abita
J P
JP
Cuttitta
F
F
Calvo
F
F
D015152:Blotting, Northern; D001839:Bombesin / Q000032:analysis* / Q000378:metabolism / Q000494:pharmacology; D001940:Breast / Q000032:analysis* / Q000187:drug effects / Q000378:metabolism; D001943:Breast Neoplasms / Q000032:analysis* / Q000378:metabolism; D002460:Cell Line; D002462:Cell Membrane / Q000032:analysis / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured / Q000032:analysis / Q000187:drug effects / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004848:Epithelium / Q000032:analysis / Q000187:drug effects / Q000378:metabolism; D005260:Female; D019886:Gastrin-Releasing Peptide; D006801:Humans; D010455:Peptides / Q000032:analysis* / Q000378:metabolism / Q000494:pharmacology; D011869:Radioligand Assay; D018004:Receptors, Bombesin; D017981:Receptors, Neurotransmitter / Q000032:analysis* / Q000187:drug effects / Q000378:metabolism; D014407:Tumor Cells, Cultured / Q000032:analysis / Q000187:drug effects / Q000378:metabolism
D003432:Cross-Linking Reagents; D010455:Peptides; D018004:Receptors, Bombesin; D017981:Receptors, Neurotransmitter; D019886:Gastrin-Releasing Peptide; D001839:Bombesin