Binding of cyclic nucleotides with proteins in malignant and adenosine cyclic 3':5'-monophosphate-induced "differentiated" neuroblastoma cells in culture (original) (raw)

Cancer Research

The binding of adenosine cyclic 3':5'-monophosphate (cyclic AMP) with soluble (100,000 X g supernatant), pellet, and total homogenate proteins from cyclic AMP-induced "differentiated" mouse neuroblastoma cells increased by about two-fold. The extent of binding with soluble proteins was higher than that with pellet proteins. The binding of cyclic AMP with soluble proteins from 5'-adenosine monophosphate-treated, serum-free medium-treated, sodium butyrate-treated, 6-thioguanine-treated, or X-irradiated neuroblastoma cells did not significantly change. When the soluble proteins containing bound cyclic [3H]AMP were filtered through a Sephadex G-25 column, the relative amount of protein-bound cyclic [3H]AMP in differentiated cells was greater than that in malignant cells, but the amount of free cyclic [3H]AMP was correspondingly less. The electrophoretic characteristics of cyclic AMP-binding proteins of differentiated and malignant cells were identical. There were t...

Cyclic AMP levels and the morphological differentiation of mouse neuroblastoma cells

1973

ABSTRACT Serum free media, prostaglandin E1 and inhibitors of cyclic nucleotide phosphodiesterase stimulate axon formation of mouse neuroblastoma cells grown in culture. These agents are shown here to also increase the basal cellular level of cyclic AMP supporting the hypothesis that cyclic AMP may be an important molecule in the differentiation process. Several inhibitors of macromolecular synthesis and assembly were examined for any effect on the neuroblastoma cell's basal or stimulated cyclic AMP level. Cycloheximide, an inhibitor of protein synthesis was observed to depress cAMP levels suggesting that protein synthesis is necessary for the maintenance of the basal cellular cyclic AMP level. Results from experiments using combinations of agents which stimulate axon formation and the inhibitors of macromolecular synthesis and assembly further support a possible relationship between cyclic AMP and the morphological differentiation of neuroblastoma.

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