DIFFERENTIAL-EFFECTS OF VARIOUS PROTEIN-KINASE-C ACTIVATORS ON PROTEIN-PHOSPHORYLATION IN HUMAN ACUTE MYELOBLASTIC-LEUKEMIA CELL-LINE KG-1 AND ITS PHORBOL ESTER-RESISTANT SUBLINE KG-1A

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  • 1 March 1987
    • journal article
    • research article
    • Vol. 47  (5) , 1302-1307
Abstract
Human myeloid leukemia KG-01 cells are induced to differentiate to macrophage-like cells by tumor-promoting phorbol esters, such as 12-O-tetradecanoylphorbol-13-acetate (TPA). Cells from the cloned subline, KG-Ia, unlike the parental line, are resistant to the differentiating effect of TPA. In the present studies, we investigated in these cells protein phosphorylation stimulated by various protein kinase C activators, including 1-oleoyl-2-acetylglycerol in the presence of the diacylglycerol kinase inhibitor R59022. TPA, mezerein, and bryostatin. All the agents stimulated, to a greater extent and with a higher potency, phosphorylation of several proteins in KG-1 cells than in Kg-1a cells. On the other hand, these agents markedly stimulated phosphorylation of other proteins in KG-1a cells compared to that in KG-1 cells. The findings indicated that the actions of the diacylglycerol, 1-oleoyl-2-acteylglycerol, and the non-metabolizable activators (TPA, mezerein, and bryostatin) were very similar but not fully equivalent; and that Kg-1a cells exhibited altered (increased or decreased) phosphorylation patterns, perhaps related to the TPA resistance characteristic of this subline of cells.

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