Neuronal differentiation of neuro 2a cells by inhibitors of cell cycle progression, trichostatin A and butyrolactone I

Trichostatin A (TSA, 17 nM), a specific and reversible inhibitor of histone deacetylase induced neurite network formation at and after 4 days. The networks were preserved for at least 3 weeks in the presence of TSA. Butyrolactone I (BLI, 23.6 microM), an inhibitor of cdc2 and cdk2 kinases, also induced neurite extension. Both compounds enhanced the acetylcholinesterase activity of the cells. Cell cycle progression of the cells was blocked by TSA (17 nM) at G1 phase alone. Furthermore, the level of histone hyperacetylation and p21(WAF1) expression in TSA-treated cells increased transiently. These findings suggest that the induction of the neuronal differentiation in Neuro 2a cells by these agents requires the cell cycle arrest at G1 phase, which is caused by inhibition of cycline dependent kinase, a target molecule of BLI and p21(WAF1).