Résumé
The studies on the factors that regulate the biology of the neuroblastoma cell lines may ofter important information on the development of tissues on organs that derive from the neural crest. In the present paper we study the action of epidermal growth factor (EGF) on two human neuroblastoma cell lines: SK-N-SH which is composed at least of two cellular phenotypes (neuroblastic and melanocytic/glial cells), and its pure neuroblastic subclone SH-SY5Y. The results show that EGF (10 ng/ml) significantly stimulates the incorporation of [3H]-thymidine in the SK-N-SH cells only in the presence of fetal bovine serum (FBS) (control = 58285 + 9327 cpm; EGF= 75523 + 4457; p<0.05). Such effect is not observed in the presence of a chemical defined medium, that is, in the absence of FBS (control = 100997 + 4375; EGF = 95268 + 4683; NS). In the SH-SY5Y cells the EGF does not modify the incorporation of [3H]thymidine either in the presence of 10 percent of BFS (control = 113838 + 6978; EGF = 119434 + 9411; NS) or in its absence (control = 46197 + 3335; EGF = 44472 + 3493; NS). The results here reported suggest that: a) EGF may effect the proliferation of cells derived from a primary human neuroblastoma; b) this is evident by the EGF-induced increase of [3H]-thymidine incorporation in SK-N-SH cells; c) it is required the presence of other growth factors, present in the FBS, for the mitogenic action to be accomphished; d) since the pure neuroblastic SH-SY5Y cell line are refractory to the EGF, the effects observed in SK-N-SH cells probably occur on the melanocytic/glial cell subpopulation.