We treated a classic neuroblastoma (NB) and a peripheral neuroepithelioma (PN) with the differentiating agents dibutyryl-cyclic (dbc) AMP and retinoic acid (RA) and evaluated the influence of several factors, such as morphologic transformation, biochemical expression, cell growth, total protein synthesis and extracellular matrix (ECM) protein synthesis to their metastatic capacity in vivo. The latter was evaluated by injecting treated and untreated cells from both lines in the tail vein of 31 nude mice. The mice were sacrificed after the injection and complete autopsies were performed. The results showed that the same differentiating agents favored a diverse pathway of differentiation in the 2 studied lines. Moreover, Schwannian transformation was associated with a remarkable increase in total protein synthesis and ECM protein synthesis and no changes in cell growth, whereas neuronal transformation was accompanied by a minor increase in total protein synthesis, decrease in ECM protein synthesis and inhibition of cell growth. Schwannian transformation was associated with a higher metastatic potential, when compared to untreated or neuronally transformed cells. The explanation of the latter phenomenon is not known. However, high levels of LM and unsaturated receptors have been alternatively implicated in the high metastatic potential of other cell types and we intend to look for LM and its receptors in the nude mice tumors from metastatic sites.
