Inhibition of growth of human malignant glioblastoma in nude mice by antagonists of bombesin/gastrin-releasing peptide

H. Kiaris, A. V. Schally, B. Sun, P. Armatis, K. Groot

Research output: Contribution to journalArticlepeer-review

45 Scopus citations

Abstract

The effects of antagonists of bombesin/gastrin-releasing peptide (GRP) on the growth of human malignant glioblastoma cell line U-87MG xenografted into nude mice were evaluated. Nude mice bearing s.c. implanted U-87MG tumors were treated with bombesin/GRP antagonists RC-3095 and RC-3940-II. RC-3095 and RC-3940-II administered s.c. at a dose of 20 μg/day for 4 weeks decreased the volume of U-87MG xenografts by 60 and 74%, respectively, compared with controls, RT-PCR analys. RT-PCR analysis showed that U-87MG xenografts expressed mRNA for bombesin receptor subtype (BRS)-1 (GRP receptor) and BRS-2 (neuromedin-B receptor), but the mRNA for GRP ligand was not detected in U-87MG cells suggesting that GRP may stimulate the growth of U-87MG glioblastomas by a paracrine mechanism. The levels of mRNA for c-fos oncogene were decreased by 30-40% in U-87MG tumors treated with RC-3095 or RC-3940-II. In U-373MG glioblastoma cells, which also express BRS-1, and U-87MG cells, cultured in vitro, GRP(14-27) induced the expression of c-fos mRNA, and some c-jun mRNA, in a time-dependent manner with the maximal effect occurring 2 h after the stimulation and a return to basal levels after 8 h. Antagonist RC-3940-II inhibited the stimulation of c-fos by GRP(14-27). Our results indicate that antagonists of bombesin/GRP inhibit the growth of U-87MG glioblastomas by a mechanism that may involve the downregulation of c-fos oncogene.

Original languageEnglish (US)
Pages (from-to)7168-7173
Number of pages6
JournalOncogene
Volume18
Issue number50
DOIs
StatePublished - Nov 25 1999
Externally publishedYes

Keywords

  • Autocrine
  • Brain tumors
  • Cancer therapy
  • Oncogene stimulation
  • Paracrine
  • Peptide analogs

ASJC Scopus subject areas

  • Molecular Biology
  • Cancer Research
  • Genetics

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