engleski

Analysis of the Role of Protein Kinase C-alpha in HL-60 Cell Proliferation and Differentiation

The role of protein kinase C (PKC) alpha in HL-60 cell proliferation and 1,25-dihidroxyvitamin D3 [1,25(OH)_2 D_3]-induced monocytic differentiation was investigated. The pretreatment of HL-60 cells with different PKC inhibitors abolished the 1,25(OH)_2 D_3-mediated effects on sphingomyelin hydrolysis, ceramide release and the activity of cytosolic, Mg^2^+-independent, neutral sphingomyelinase. Immunodepletion studies shown that of all classical, novel and atypical isoforms tested, only the depletion of PKCalphafrom cytosol completely inhibited the activation of sphingomyelinase induced by 1,25(OH)_2D_3. The most specific PKC inhibitors were further used in order to investigate the role of PKC in 1,25(OH)_2D_3-induced growth arrest and monocytic marker expression in HL-60 cells. The treatment of HL-60 cells with calphostin C, an inhibitor of classical and novel PKC isoforms, induced apoptosis. The pretreatment of HL-60 cells with Gö 6976, a specific inhibitor of PKCalpha and beta1, had no effects on 1,25(OH)_2D_3-mediated induction of CD14 expression. The treatment for 24 to 72 hours with Gö 6976 alone caused the progressive increase in the relative number of G1 DNA cells.

protein kinase-C; HL-60 cell; proliferation; differantiation

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