Type I and type II insulin-like growth factor receptors and their function in human Ewing's sarcoma cells

摘要: Binding studies using recombinant human125I-labelled insulin-like growth factor I ([125I]IGF-I) revealed IGF-I receptors in three Ewing's sarcoma cell lines withKd ranging from 74×10−12M to 100×10−12M andBmax=36–63 fmol/mg protein. [125I]IGF-I binding was displaced by IGF-I, IGF-II and insulin with IC50 values of 1.5 nM, 6.3 nM 0.7 μM respectively. Recombinant human [125I]IGF-II radioligand-binding assays the disclosed specific sites for withKd=(110–175)×10−12M andBmax varying 21 72 Neither nor binding. found increase basal glucose transport maximally times EC50=0.9 IGF-I. The efficacy potency on uptake were comparable those whereas ineffective. also provoked stimulation glycogen synthesis cells. maximal glycogenic response reached at 0.01 0.1 IGF-II, EC50 value being approximately 1 2 IGF-II. Insulin did not significantly influence formation. but increased DNA mitogenic obtained 10 or an about both peptides. α-IR-3, a monoclonal antibody IGF type receptor, effectively blocked IGF-I- IGF-II-mediated metabolic responses. In conclusion, data show that induce rapid longterm biological responses cells exclusively through interaction receptors.