The IGF-I receptor protects tumor cells from apoptosis induced by high concentrations of serum.
High concentrations of fetal bovine serum (FBS) induce apoptosis of cells in culture. A decrease in the number of insulin-like growth factor I receptors (IGF-IR) sensitizes the cells to serum-induced apoptosis. Autophosphorylation of the IGR-IR is not affected by high serum. These results may explain why the targeting of the IGF-IR renders tumor cells much more sensitive to apoptosis in vivo than in vitro.
Valentinis
B
B
Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
Baserga
R
R
D000818:Animals; D017209:Apoptosis; D001769:Blood; D002417:Cattle; D002455:Cell Division; D002460:Cell Line; D003470:Culture Media; D016895:Culture Media, Serum-Free; D046508:Culture Techniques / Q000379:methods; D004273:DNA, Neoplasm / Q000032:analysis; D005434:Flow Cytometry; D005909:Glioblastoma; D007700:Kinetics; D010766:Phosphorylation; D051381:Rats; D017526:Receptor, IGF Type 1 / Q000378:metabolism / Q000502:physiology*; D011994:Recombinant Proteins / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured
D003470:Culture Media; D016895:Culture Media, Serum-Free; D004273:DNA, Neoplasm; D011994:Recombinant Proteins; D017526:Receptor, IGF Type 1