Nerve growth factor-induced differentiation of human neuroblastoma and neuroepithelioma cell lines

A series of neuroepithelioma and neuroblastoma cell lines were screened for nerve growth factor (NGF)-induced differentiation. All three neuroepithelioma cell lines and all nine neuroblastoma cell lines with amplified N-myc oncogene did not show any apparent NGF-induced differentiation. However, neurite extension was observed for three of six neuroblastoma cell lines with single-copy N-myc oncogene. The three responsive lines had a neuronal phenotype (short processes) which was enhanced by the addition of NGF. The three nonresponsive cell lines were flat without any processes. The addition of NGF to the responsive cell lines resulted in an up-regulation of neurofilament mRNA expression. Peripherin and synapsin, two markers of terminal neuronal differentiation, were not induced. There was little effect of NGF on the rate of cell growth or colony formation on soft agar. Binding of NGF to eight of the cell lines was analyzed by the method of Scatchard. Two responsive neuroblastoma cell lines and one nonresponsive neuroepithelioma cell line expressed both low- and high-affinity binding sites. Two nonresponsive neuroblastoma cell lines expressed only a small number of high-affinity binding sites, and two other nonresponsive neuroblastoma cell lines did not detectably bind NGF. Hence, NGF-induced differentiation is confined to a particular class of neural-related tumors, and, even for these cell lines, differentiation is incomplete.