Nerve growth factor may stimulate either division or differentiation of cloned C1300 neuroblastoma cells in serum-free cultures.

Two clones of mouse C1300 neuroblastoma cells (clones NB1R and NB6R) bind mouse 2.5S Nerve Growth Factor (NGF) in vitro. The ligand is then capped and internalized by the cells. This step requires active cell processing. In serum-free or low serum conditions, clear effects of NGF are seen with both clones. Cultured NB1R cells are stimulated, after a lag interval of a few hours, to synthesize DNA and to proliferate, whereas NB6R cells are stimulated to cell differentiation and maintain viability under these conditions much longer than similar cultures in the absence of NGF. Stimulation of clone NB1R occurs within an optimal dose concentration of the same order as that used in the Levi-Montalcini bioassay with 8-day-old chick embryo-sensitive ganglia; the effects on clone NB6R, however, need higher NGF concentrations. Both effects are protein-specific since they are inhibited in the presence of added anti-NGF antibodies. This system could provide a convenient means to study the control of cell division in susceptible malignant neuroblastoma clones and to correlate NGF binding to receptors and biological activity.