Protein kinase C-mediated inhibition of cyclin A expression in human vascular endothelial cells.
Proliferation of cultured human vascular endothelial cells may be negatively regulated by the protein kinase C (PKC) pathway, because phorbol 12-myristate, 13-acetate (PMA) inhibits DNA synthesis and cell population doubling in PKC-retaining cells, but not in cells depleted of PKC by a long-term exposure to PMA. We investigated the mechanism through which PKC arrests the cell cycle with regard to cyclin A, which has been reported to play a key role in G1/S progression activating CDK2. Cyclin A mRNA was elevated from late G1 in accordance with the protein expression, which reached the maximal level during the S phase. PMA added at late G1 potently reduced the levels of cyclin A mRNA and the protein in concentration-dependent manners parallel to its effect on the proliferation. However, it failed to inhibit the expression in PKC-depleted cells. The mRNA reduction by PMA was due to inhibition of the transcription. The PMA effects were mimicked by multiple doses of 1,2-dioctanoylglycerol. These findings suggest that PKC inhibits G1/S progression through suppression of cyclin A gene transcription in endothelial cells.
Kosaka
C
C
National Cardiovascular Center Research Institute, Osaka, Japan.
Sasaguri
T
T
Masuda
J
J
Zen
K
K
Shimokado
K
K
Yokota
T
T
Ogata
J
J
D015153:Blotting, Western; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D016213:Cyclins / Q000096:biosynthesis*; D004261:DNA Replication / Q000187:drug effects; D004075:Diglycerides / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D007700:Kinetics; D011493:Protein Kinase C / Q000096:biosynthesis / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000378:metabolism / Q000494:pharmacology; D013997:Time Factors; D014471:Umbilical Veins
D016213:Cyclins; D004075:Diglycerides; D012333:RNA, Messenger; D016222:Fibroblast Growth Factor 2; C044295:1,2-dioctanoylglycerol; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate