Protein kinase C activation and down-regulation in relation to phorbol ester-induced differentiation of SH-SY5Y human neuroblastoma cells.
The role of protein kinase C activation in changes in muscarinic receptor functions and in the appearance of biochemical properties characteristic of neuronal cells was studied in SH-SY5Y human neuroblastoma cells induced to differentiate with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA). A decrease in muscarinic receptor sensitivity with respect to agonist induced Ca2+ mobilization and receptor number parallelled the increase in membrane-associated protein kinase C (PK-C) activity. These changes occurred during the first 6 h of culture, and they were associated with rounding-up of cells. A subsequent decrease in particulate PK-C activity was followed by an increase in noradrenaline content, the appearance of an electrically excitable membrane, and an increase in the level of neuron-specific enolase. These changes were accompanied by a pronounced neurite outgrowth. 1-(5-Isoquinolinesulphonyl)-2-methylpiperazine (H-7), an inhibitor of PK-C and cyclic nucleotide-dependent protein kinases, enhanced the morphological differentiation induced by TPA, whereas N-(2-guanidinoethyl)-5-isoquinolinesulphonamide (HA-1004), which primarily inhibits cyclic nucleotide-dependent protein kinases, had no effect on the TPA-induced phenotypic differentiation. H-7 inhibited the decrease in muscarinic receptor sensitivity and receptor number, but had no effect on the appearance of the electrically excitable membrane or on the increase in the neuron-specific enolase level. Both H-7 and HA-1004 inhibited the TPA-induced increase in noradrenaline content.
Heikkilä
J E
JE
Department of Biochemistry and Pharmacy, Abo Academy, Finland.
Akerlind
G
G
Akerman
K E
KE
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D002118:Calcium / Q000502:physiology; D015220:Calcium Channels / Q000502:physiology; D002451:Cell Compartmentation / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D004075:Diglycerides / Q000494:pharmacology; D004789:Enzyme Activation; D006801:Humans; D007546:Isoquinolines / Q000494:pharmacology; D008564:Membrane Potentials; D009447:Neuroblastoma / Q000473:pathology*; D010879:Piperazines / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism*; D047428:Protein Kinase Inhibitors; D011976:Receptors, Muscarinic / Q000502:physiology; D013449:Sulfonamides; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D013997:Time Factors; D014407:Tumor Cells, Cultured
D015220:Calcium Channels; D004075:Diglycerides; D007546:Isoquinolines; D010879:Piperazines; D047428:Protein Kinase Inhibitors; D011976:Receptors, Muscarinic; D013449:Sulfonamides; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; C043204:N-(2-guanidinoethyl)-5-isoquinolinesulfonamide; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium; C013965:diolein