SENSITIVITY TO 2,5-HEXANEDIONE OF NEUROFILAMENTS IN NEUROBLASTOMA CELL-LINE SK-N-SH INCREASES DURING DIFFERENTIATION

The effect of 2,5-hexanedione (2,5-HD) on the distribution of the neur ofilamental (NF) proteins and vimentin was examined in human neuroblas toma cell line SK-N-SH with immunocytochemical methods. Retinoic acid (10 mu M) induced differentiation into neuronal cells resulting in the outgrowth of processes and synthesis of NF proteins in the majority o f the cells. A minority (4%) differentiated as large fibroblasts. Cell s were exposed to 0-10 mM 2,5-HD for 3 days. In neuronal cells a conce ntration-dependent accumulation of NF proteins was detected as a spher ical structure in the perikaryon. Neurofilaments in differentiated SK- N-SH cells were more susceptible to 2,5-HD than NF in undifferentiated cells, as the effects were observed at much lower 2,5-HD concentratio ns. In contrast, no accumulation of vimentin was detected in the fibro blastic cells.