In vitro differentiation of human neuroblastoma cells induced by sodium phenylacetate.

Sodium phenylacetate (NaPA) at concentrations ranging from 2 to 6 mM stimulated morphological differentiation of two human neuroblastoma cell lines IMR-32 and UKF-NB-3. These concentrations inhibited growth and DNA synthesis of the cells in a dose dependent manner without significant effect on cell viability. The differentiated cells showed pseudoganglia formation and extension of cellular processes. The morphological differentiation in both cell lines was accompanied by decreased expression of N-myc oncoprotein. These results suggest that NaPA at concentrations, which have been achieved in humans with no significant adverse effects, promotes differentiation of cultured human neuroblastoma cells in association with the reduced expression of the malignant phenotype.