Characterization of neuronal differentiation factor(s) produced by Kagura-2 cells established from aflatoxin B1-induced rat hepatoma

Abstract

Recently we have demonstrated that the growth of Kagura-2 cells established from aflatoxin B1 (AFB1)-induced rat hepatoma was markedly stimulated by glucocorticoids (GCs). To investigate a possible role of GCs in the growth of Kagura-2 cells, we studied the effect of conditioned medium (CM) prepared from Kagura-2 cells on the neuronal differentiation of pheochromocytoma (PC12) cells. Kagura-2 cell-CM caused in PC12 cells a number of physiological changes which mimic the nonreplicating sympathetic neuron-like cells, including induction of neurite extension and acetylcholinesterase activity. The neuronal differentiation factor(s) in CM were inactivated by the treatments of trypsin, acetic acid, dithiothreitol and heat. The molecular weights of factor(s) ranged from 6,000 to 14,000 on the basis of experiments using various molecular weight cutoff dialysis tubing and gel filtration.