Expression of type I, but not type II insulin-like growth factor receptor on both undifferentiated and differentiated HT29 human colon carcinoma cell line. - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Clinical Endocrinology and Metabolism Année : 1992

Expression of type I, but not type II insulin-like growth factor receptor on both undifferentiated and differentiated HT29 human colon carcinoma cell line.

J Culouscou
  • Fonction : Auteur
Fl Garrouste
  • Fonction : Auteur
C Rabenandrasana
J. Marvaldi
  • Fonction : Auteur
G. Pommier
  • Fonction : Auteur

Résumé

The HT29 human colonic carcinoma cell line secretes insulin-like growth factor (IGF)-II. We have examined these cells for expression of IGF receptors. Competitive binding assays as affinity cross-linking experiments using 125I-IGF-II fail to reveal type II IGF receptors at the cell surface. In contrast, cross-linking studies with either 125I-IGF-I or 125I-IGF-II reveal an M(r) 135,000 protein that follows a peptide binding specificity characteristic of the alpha-subunit of the type I IGF receptor. However, 125I-IGF-II binding to this receptor is not inhibited at 4 C by alpha IR-3, a monoclonal antibody to the type I IGF receptor. Analysis of the competitive binding curves with each one of these radioligands suggests that HT29 cells express both a classical type I IGF receptor (about 6,000/cell; KdIGF-I = 0.48 nmol) and a variant one whose 125I-IGF-II binding is not blocked by alpha IR-3 (about 15,000/cell; KdIGF-II = 4.0 nmol). Endocytosis studies of specific cell-bound 125I-IGF-I or 125I-IGF-II suggest that ligand interaction with the classical, but not the variant, binding site is only able to induce receptor internalization. An identical IGF receptors pattern is observed with HT29-D4 clonal cells induced to differentiate by culture in a glucose-free medium.
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hal-02136045 , version 1 (21-05-2019)

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M Remacle-Bonnet, J Culouscou, Fl Garrouste, C Rabenandrasana, J. Marvaldi, et al.. Expression of type I, but not type II insulin-like growth factor receptor on both undifferentiated and differentiated HT29 human colon carcinoma cell line.. Journal of Clinical Endocrinology and Metabolism, 1992, 75 (2), pp.609-616. ⟨10.1210/jcem.75.2.1322432⟩. ⟨hal-02136045⟩

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