The epidermal growth factor-mediated inhibition of growth in A431 cells is accompanied by an atypical stimulation of protein breakdown.
Addition of epidermal growth factor (EGF) to serum-free or serum-supplemented cultures of A431 cells stimulates protein breakdown without affecting rates of protein synthesis. These effects are atypical because in other cell lines, including AG2804-transformed human fibroblasts examined for comparison, EGF inhibits protein breakdown and stimulates protein synthesis. The response to EGF in A431 cells does not reflect a general post-receptor modification in growth factor action, since addition of insulin to the cells leads to the normal inhibition of protein breakdown. These findings indicate that the unusual growth inhibition produced by EGF in A431 cells can be explained by an increased rate of intracellular protein breakdown.
D002294:Carcinoma, Squamous Cell / Q000473:pathology; D002455:Cell Division; D002460:Cell Line; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D066246:ErbB Receptors; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D011506:Proteins / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000502:physiology*
D007328:Insulin; D011506:Proteins; D011956:Receptors, Cell Surface; D004815:Epidermal Growth Factor; D066246:ErbB Receptors