Cholera toxin inhibits signal transduction by several mitogens and the in vitro growth of human small-cell lung cancer

J. Viallet, Y. Sharoni, H. Frucht, R. T. Jensen, J. D. Minna, E. A. Sausville

Research output: Contribution to journalArticle

28 Scopus citations

Abstract

Cholera toxin (CT) inhibited the in vitro growth of three of four human small-cell lung carcinoma (SCLC) cell lines with a 50% inhibitory concentration of 27-242 ng/ml. Loss of surface membrane ruffling and the capacity of [Tyr4]-bombesin, vasopressin, and fetal calf serum to stimulate increases in intracellular free calcium clearly preceded effects on cellular metabolic activity and cell growth. 125I-[Tyr4]-bombesin binding was unaffected by CT treatment but [Tyr4]-bombesin stimulated phospholipase C activity was decreased in membranes from CT-treated SCLC cells. CT stimulated a rapid but transient increase in intracellular cyclic AMP ([cAMP](i)) in SCLC. The effect of CT on susceptible SCLC were not reproduced by elevations of [cAMP](i) induced by forskolin or cyclic AMP analogues. G(M1) ganglioside, the cellular binding site for CT, was highly expressed in the CT-sensitive but not the CT-resistant SCLC cell lines. In contrast, expression of guanine nucleotide binding protein substrates for ADP-ribosylation by CT was similar. These data demonstrate the existence of a CT-sensitive growth inhibitory pathway in SCLC-bearing G(M1) ganglioside. Addition of CT results in decreased responsiveness to several mitogenic stimuli. These results suggest novel therapeutic approaches to humans SCLC.

Original languageEnglish (US)
Pages (from-to)1904-1912
Number of pages9
JournalJournal of Clinical Investigation
Volume86
Issue number6
DOIs
StatePublished - Jan 1 1990

Keywords

  • G protein
  • cyclic adenosine monophosphate
  • gastrin-releasing peptide
  • growth factor
  • phospholipase C

ASJC Scopus subject areas

  • Medicine(all)

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