Insulin-Like Growth Factors are Mitogenic for Human Keratinocytes and a Squamous Cell Carcinoma

摘要: Normal adult human keratinocytes in monolayer culture and SCL-1, a skin-derived squamous-cell carcinoma cell line, were investigated for the expression of receptors insulin- like growth factors (IGF) insulin. As demonstrated by affinity crosslinking, radiolabeled IGF-1, IGF-2, insulin bound specifically to both types. Each expressed type I IGF receptors, with IGF-1 > IGF-2 >> Insulin highest insulin, also present on cells. However, SCL-1 cells differed 125I-IGF-2 binding. 1251-JGF-2-bound II normal keratinocytes, but predominantly membrane-associated binding proteins SCL-1. was slightly more potent than stimulating In concentrations ranging from 5–100 ng/ml, 50–100 resulted significant increase number. At maximum dose 100 either or caused 2.3-times cells, at lower concentrations, maximal concentration 333 ng/ml stimulated 4.7-times thymidine incorporation. The stimulatory effect 10–50 times less that IGF. completely inhibited receptor antibody alphaIR-3, suggesting IGFs are mitogenic through receptor. action partially blocked alphalR-3, can act receptors. It thus appears mitogens transformed their actions primarily mediated receptor, whereas is mitogen