DFMO and retinoic acid induce two different types of morphological changes in a human neuroblastoma cell line

The human neuroblastoma SK-N-BE(2) cell line, treated with either retinoic acid (RA) or α-difluoromethylornithine (DFMO) has already proved to be a suitable system to analyze stable in vitro differentiation towards neurocrest specific cell types. With the present study we show that the expression of the Nmyc oncogene is reduced in both RA and DFMO induced cell populations. This is a typical indication of cell differentiation in the nervous system. Ultrastructural analysis shows that the cells treated with either of the two agents undergo morphological changes that render them different between themselves as well as with the untreated population. The changes go in the direction of neural characteristics for RA treated cells, and Schwannian-like characteristics for DFMO induced cells. These results confirm our previous morphological and biochemical observations.