Divergent changes of chromogranin A/secretogranin II levels in differentiating human neuroblastoma cells.

Human neuroblastoma cells were cultured either in the absence or presence of 12-O-tetradecanoylphorbol-13-acetate (TPA) known to induce neuronal differentiation. This treatment led to a marked increase in the concentration of secretogranin II but to a decrease of chromogranin A. Analogous changes were observed for the respective mRNAs. Thus during differentiation of these cells the biosynthesis of two vesicle constituents of large dense core vesicles is differentially regulated as determined both at the mRNA and the protein level. Levels of both synaptin/synaptophysin large dense core vesicles is differentially regulated as determined both at the mRNA and the protein level. Levels of both synaptin/synaptophysin and SV2 were also elevated but to a smaller degree than that of secretogranin II.