Characterization of bombesin/gastrin-releasing peptide receptors in membranes of MKN45 human gastric cancer

Gabor Halmos, Jacek Pinski, Balazs Szoke, Andrew V. Schally

Research output: Contribution to journalArticlepeer-review

28 Scopus citations

Abstract

Binding of the radiolabeled bombesin analog [125I-Tyr4]bombesin to crude cell membranes of MKN45 human gastric cancer grown in nude mice was investigated in vitro. Scatchard analyses of multipoint binding data, performed by complete displacement method demonstrated the presence of two classes of [Tyr4]bombesin binding sites. The high-affinity binding sites had a mean dissociation constant (Kd1) of 2.75 nM with a mean maximal binding capacity (Bmax1) of 492 fmol/mg membrane protein, while the low-affinity binding sites showed a mean dissociation constant (Kd2) of 0.41 μM with a mean maximal binding capacity (Bmax2) of 41.4 pmol/mg membrane protein. Binding of [125I-Tyr4]bombesin was specific, reversible and linearly related to the protein concentration of tumor membrane. In displacement studies, the binding of radiolabeled [Tyr4]bombesin was inhibited in a dose-dependent manner by gastrin releasing peptide (GRP)(14-27) and two synthetic antagonists of bombesin/GRP, RC-3095 and RC-3950-II. Both antagonists exhibited high affinity in nearly the same concentration range as GRP(14-27). The presence of receptors for bombesin/GRP on human gastric cancer membranes suggests that bombesin-like peptides may play a role in growth of gastric cancer.

Original languageEnglish (US)
Pages (from-to)111-118
Number of pages8
JournalCancer letters
Volume85
Issue number1
DOIs
StatePublished - Sep 30 1994
Externally publishedYes

Keywords

  • Bombesin/GRP receptors
  • Human gastric cancer cell line

ASJC Scopus subject areas

  • Cancer Research
  • Molecular Biology
  • Oncology

Fingerprint

Dive into the research topics of 'Characterization of bombesin/gastrin-releasing peptide receptors in membranes of MKN45 human gastric cancer'. Together they form a unique fingerprint.

Cite this