Phosphatidylcholine could be the source of 1,2-DAG which activates protein kinase C in EGF-stimulated colon carcinoma cells (HT29).
In our previous study (A. Balogh et al, Cell. Signalling 5 (6), 795-802, 1993.), we have shown that epidermal growth factor (EGF) increased protein kinase C (PKC) activities in colon carcinoma cell line (HT29), possibly through the increased 1,2-diacylglycerol (1,2-DAG) production via phosphatidylcholine (PC). Here we investigate the effect of well-known PKC activator 12-O-tetradecanoyl-2 phorbol-13-acetate (TPA), on the levels of 32P incorporation into EGF induced phosphatidylinositols (PI, PI4P, PI4, 5P2) and different phospholipids (PC, PA, PS) as well as on induced tyrosine kinase activity. TPA significantly decreased the effects of EGF and it had the biggest inhibitory effect on EGF induced PC level. These data support our contention that PC plays an important role in the activation of PKC via 1,2-DAG production in the EGF stimulated pathway.
Balogh
A
A
First Institute of Biochemistry, Semmelweis University Medical School, Hungarian Academy of Sciences, Budapest, Hungary.
Csuka
O
O
Teplán
I
I
Kéri
G
G
D003110:Colonic Neoplasms / Q000473:pathology*; D004075:Diglycerides / Q000378:metabolism*; D004347:Drug Interactions; D004789:Enzyme Activation / Q000187:drug effects; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D066246:ErbB Receptors / Q000378:metabolism; D019073:HT29 Cells; D006801:Humans; D010710:Phosphates / Q000378:metabolism; D010713:Phosphatidylcholines / Q000378:metabolism*; D010716:Phosphatidylinositols / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism*; D015398:Signal Transduction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
C011439:1,2-diacylglycerol; D004075:Diglycerides; D010710:Phosphates; D010713:Phosphatidylcholines; D010716:Phosphatidylinositols; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate