Specific role for protein kinase C beta in cell differentiation.
A critical role for protein kinase C (PKC) in signal transduction events has been well established. On the other hand, emerging evidence also suggests a role for regulation of PKC levels in mediating long term cellular functions. In human leukemia cell line HL-60, the action of 1,25-dihydroxyvitamin D3 results in transcriptional up-regulation of PKC beta (within 8-12 h) (L. M. Obeid et al., J. Biol. Chem., 265: 2370-2374, 1990). In this study, the role of PKC beta in the regulation of proliferation and differentiation was studied. 1,25-Dihydroxyvitamin D3 caused an increase in PKC beta I, beta II, and, to a lesser extent, PKC alpha, as determined by Western blot analysis. This increase was accompanied by inhibition of proliferation and induction of differentiation. The addition of a 25-base pair antisense oligonucleotide directed against the 5' coding sequence of PKC beta attenuated up-regulation of PKC beta I and beta II levels in response to 1,25-dihydroxyvitamin D3. This antisense oligonucleotide, but not sense oligonucleotide or antisense oligonucleotide to PKC alpha, caused inhibition of 1,25-dihydroxyvitamin D3-induced differentiation by 25-45%. On the other hand, inhibition of cell proliferation by 1,25-dihydroxyvitamin D3 was minimally affected by the addition of antisense oligonucleotides. These results identify a role for PKC beta in cell differentiation and underscore the significance of transcriptional activation of PKC as a mechanism for long-term regulation of PKC. The results also distinguish signaling pathways involved in cell differentiation from those involved in antiproliferation.
Gamard
C J
CJ
Division of Hematology/Oncology, Duke University Medical Center, Durham, North Carolina 27710.
Blobe
G C
GC
Hannun
Y A
YA
Obeid
L M
LM
D001483:Base Sequence; D002117:Calcitriol / Q000037:antagonists & inhibitors / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute; D008969:Molecular Sequence Data; D016376:Oligonucleotides, Antisense; D011493:Protein Kinase C / Q000502:physiology*; D064546:Protein Kinase C beta; D014407:Tumor Cells, Cultured
D016376:Oligonucleotides, Antisense; D011493:Protein Kinase C; D064546:Protein Kinase C beta; D002117:Calcitriol