Incorporation of 12(S)-hydroxyeicosatetraenoic acid into phospholipids and active diacylglycerols in rat liver epithelial cells: effects on DNA synthesis.
12(S)-Hydroxyeicosatetraenoic acid (12-HETE), the 12-lipoxygenase-derived metabolite of arachidonic acid, was incorporated into membrane phospholipids (PL) in various cells. PL are precursors of diacylglycerol (DAG), a protein kinase C (PKC) activator involved in cell-growth signaling. We studied 12-HETE incorporation into PL in non-transformed (NT-) and spontaneously transformed (T-) rat liver epithelial cells (RLEC), and its consequence on DNA synthesis. NT- and T-RLEC incorporated 12-HETE predominantly into phosphatidylcholine (PC). 12-HETE was incorporated at a greater rate, and with a higher phosphatidylethanolamine (PE)/PC ratio in T-cells. Preincubation of RLEC with 12-HETE at > or = 0.5 microM partially inhibited basal DNA synthesis in NT- and T-RLEC. Preincubation of NT-RLEC with 12-HETE (2.5 microM) also decreased bradykinin-stimulated DNA synthesis. Unstimulated RLEC produced 1-acyl-2-(12-HETE)DAG which was increased in NT-RLEC by bradykinin stimulation. Finally, 1-stearoyl-2-(12-HETE)DAG was as potent an in vitro PKC activator as 1-stearoyl-2-arachidonyl-DAG. These data demonstrate that 12-HETE incorporation into PL resulted in the production of active 12-HETE-containing DAG, together with reduced DNA synthesis.
Vernhet
L
L
Groupe de Recherche sur les Signaux Lipidiques Membranaires, Faculté des Sciences Pharmaceutiques et Biologiques, Université de Rennes I, France.
Hichami
A
A
Hamon
L
L
Cochet
M F
MF
Legrand
A B
AB
D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid / Q000378:metabolism*; D000818:Animals; D002455:Cell Division / Q000187:drug effects; D004247:DNA / Q000096:biosynthesis; D004075:Diglycerides / Q000096:biosynthesis*; D004789:Enzyme Activation; D004847:Epithelial Cells; D004848:Epithelium / Q000378:metabolism; D006801:Humans; D007231:Infant, Newborn; D008099:Liver / Q000166:cytology* / Q000378:metabolism; D010743:Phospholipids / Q000096:biosynthesis*; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats
D004075:Diglycerides; D010743:Phospholipids; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D004247:DNA; D011493:Protein Kinase C