The overexpression of insulin receptor makes CHO cells resistant to the action of IGF-1: Role of IRS-1

D. Maggi, C. Laurino, G. Andraghetti, R. Cordera

Research output: Contribution to journalArticle

Abstract

We investigated the influence of the relative abundance of insulin and IGF-1 receptors on cellular growth, by measuring the stimulation of c-fos expression and of 3H-thymidine incorporation into DNA by insulin and IGF-1 in CHO cells overexpressing Insulin Receptor (CHO-IR). We found that CHO-IR cells were resistant to the action of IGF-1, but were more responsive to insulin, compared to parental clone. This result suggested the presence of a limiting step, distal to the IGF-1 receptor, in the transduction pathway. To address this question we measured the IGF-1 effect on c-fos expression in CHO-IR cells, transiently transfected with the cDNA for IRS-1, the common intracellular substrate for both insulin and IGF-1 receptors (CHO-IR/IRS-1 cells). In these cells IGF-1 stimulated a 10 fold higher c-fos expression compared to CHO-IR cells. These results suggest that the abundance of IRS-1, relative to the number of insulin and IGF-1 receptors, represents a limiting step for the intracellular transduction of insulin and IGF-1 biological messages.

Original languageEnglish
Pages (from-to)693-699
Number of pages7
JournalBiochemical and Biophysical Research Communications
Volume205
Issue number1
DOIs
Publication statusPublished - 1994

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

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