Expression and function of the insulin-like growth factor I system in human non-small-cell lung cancer and normal lung cell lines

Int J Cancer. 1994 Mar 15;56(6):858-66. doi: 10.1002/ijc.2910560618.


In order to analyze the presence and the function of the "insulin-like growth factor I (IGF-I) system" in human non-small-cell lung cancer (N-SCLC) we tested 5 cell lines of different histological sub-types: A549, Ca-Lu-6, SK-Lu-1 (adenocarcinoma); Ca-Lu-1, SK-Mes-1 (squamous carcinoma) and one normal fibroblast-like fetal lung cell line (IMR-90) for expression of the IGF-I peptide and its RNA transcribed from the IGF-I gene; IGF-binding proteins (IGF-BP); IGF-I receptor (IGF-I-R) and its mRNA. In addition, we examined the capacity of exogenous human recombinant IGF-I to enhance the in vitro cell proliferation. In medium conditioned from cell cultures, we detected immunoreactive IGF-I material by radioimmunoassay. Western ligand blot and affinity labelling demonstrated the presence of several molecular species of IGF-BPs (IGF-BP-4, -1, -2, -3) as well. Northern blot analysis of polyA+ RNA from all cell lines examined revealed the presence of IGF-I and IGF-I-R mRNA. Moreover, binding studies on cultured cell lines showed one class of high-affinity, operative type-I IGF cell-surface binding sites. Finally, by thymidine uptake and colorimetric metabolic MTT assays, we found that most neoplastic cell lines react mitogenically to IGF-I and that its physiological effect is abolished by an anti-IGF-I-receptor antibody. These data indicate the importance of the IGF-I system in N-SCLC growth. Furthermore, they suggest that this mitogenic complex should be appraised as a possible target for anti-neoplastic drugs, antibodies or growth-factor analogues offering potential new approaches to therapy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding, Competitive
  • Carcinoma, Non-Small-Cell Lung / chemistry*
  • Carrier Proteins / analysis*
  • Cell Line
  • Dose-Response Relationship, Drug
  • Humans
  • Insulin-Like Growth Factor Binding Proteins
  • Insulin-Like Growth Factor I / analysis*
  • Insulin-Like Growth Factor I / metabolism
  • Insulin-Like Growth Factor I / pharmacology
  • Lung / chemistry*
  • Lung Neoplasms / chemistry*
  • RNA, Messenger / analysis
  • Receptor, IGF Type 1 / analysis*
  • Receptor, IGF Type 1 / metabolism
  • Tumor Cells, Cultured


  • Carrier Proteins
  • Insulin-Like Growth Factor Binding Proteins
  • RNA, Messenger
  • Insulin-Like Growth Factor I
  • Receptor, IGF Type 1