Potentiation of PGE(2)-mediated cAMP production during neuronal differentiation of human neuroblastoma SK-N-BE(2)C cells

Abstract

The prostagland in-evoked cAMP production was studied in human neuroblastoma SK-N-BE(2)C cells during neuronal differentiation induced by all-trans retinoic acid. The incubation with 5 mum all-trains retinoic acid for 4-6 days promoted neurite outgrowth of cells. After differentiation, prostaglandin E-2 (PGE(2))-induced cAMP production was dramatically increased, whereas forskolin- and AIF -induced cAMP productions were not changed. The increase reached maximum after 4-days of incubation with all-trans retinoic acid. The differentiation caused an increase in the maximal response and a decrease in the half-maximal effective concentration of the PGE(2)-induced cAMP production. In addition, the binding of [3H]PGE(2) to membrane receptors was enhanced in differentiated cells. However, the order of potency of the various prostaglandins (PGE(1) = PGE(2) > PGD2 = PGF2 alpha = PGI(2)) incAMP production did not change during the differentiation, suggesting that mainly E-prostanoid (EP) receptors were involved. Butaprost, an EP2 receptor specific agonist, increased the cAMP level in a concentration dependent manner and had a similar potentiating effect on cAMP production as PGE(2) upon differentiation. Northern blot analysis using the human cDNA probes shows that the EP2 mRNA level was about seven times higher in differentiated cells, while the dopamine P-hydroxylase (DBH) mRNA completely disappeared. Our results, thus, suggest that elevated gene expression of the prostanoid EP2 receptor results in an increase in the PGE(2)-evoked cAMP production in SK-N-BE(2)C cells during neuronal differentiation.