High affinity receptors for bombesin/GRP-like peptides on human small cell lung cancer |
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Authors: | T W Moody D N Carney F Cuttitta K Quattrocchi J D Minna |
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Affiliation: | 1. Department of Biochemistry, The George Washington University School of Medicine and Health Sciences, Washington, D.C. 20037, USA;2. NCI-Navy Medical Oncology Branch, National Cancer Institute, National Institutes of Health and Naval Hospital, Bethesda, MD 20814, USA |
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Abstract: | The binding of a radiolabeled bombesin analogue to human small cell lung cancer (SCLC) cell lines was investigated. (125I-Tyr4)bombesin bound with high affinity (Kd = 0.5 nM) to a single class of sites (2,000/cell) using SCLC line NCI-H446. Binding was reversible, saturable and specific. The pharmacology of binding was investigated using NCI-H466 and SCLC line NCI-H345. Bombesin and structurally related peptides, such as gastrin releasing peptide (GRP), but not other peptides, such as substance P or vasopressin, inhibited high affinity (125I-Tyr4)BN binding activity. Finally, the putative receptor, a 78,000 dalton polypeptide, was identified by purifying radiolabeled cell lysates on bombesin or GRP affinity resins and then displaying the bound polypeptides on sodium dodecylsulfate polyacrylamide gels. Because SCLC both produces bombesin/GRP-like peptides and contains high affinity receptors for these peptides, they may function as important autocrine regulatory factors for human SCLC. |
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Keywords: | Address all correspondence to Dr. Terry W. Moody |
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