A lysophosphatidic acid analogue is revealed as a potent inhibitor of phosphatidylcholine synthesis, inducing apoptosis.
A previous study demonstrated that cross-desensitization experiments performed with the lysophosphatidic acid (LPA) analogues (R)- and (S)-N-palmitoyl-norleucinol 1-phosphate (PNPAs) inhibited LPA-induced platelet aggregation without any stereospecificity. Here we report opposite biological effects of the two enantiomers on mitogenesis of IMR-90 fibroblasts in relation to their respective metabolism. (R)PNPA was proliferative, while (S)PNPA induced apoptosis by specifically inhibiting phosphatidylcholine biosynthesis at the last step of the CDP-choline pathway controlled by cholinephosphotransferase. This effect was not direct but required dephosphorylation of PNPAs by ecto-lipid phosphate phosphatase before cellular uptake of the generated N-palmitoyl-norleucinols (PNOHs). Inhibition of cholinephosphotransferase by the derivative (S)PNOH was confirmed by an in vitro assay. (S)PNPA proapoptotic effects led us to clarify the mechanism linking cholinephosphotransferase inhibition to apoptosis. Three proapoptotic responses were observed: the activation of caspase-3, the production of ceramides from newly synthesized pools (as demonstrated by the inhibitor Fumonisin B1) and finally the activation of stress-activated protein kinase, p38 and c-Jun N-terminal kinases 1/2, as a result of ceramide increase. Thus our data demonstrate that synthetic analogues of LPA might display stereospecific effects leading to apoptosis independently of classical LPA-activated pathways.
Institut fédératif de recherche Claude de Préval, INSERM U326, Phospholipides membranaires, Signalisation cellulaire et Lipoprotéines, Hôpital Purpan, 31059 Toulouse Cedex, France.
Geneviéve
G
Gueguen
Virginie
V
Granci
Pierre
P
Rogalle
Fabienne
F
Briand-Mésange
Michéle
M
Wilson
Alain
A
Klaébé
François
F
Tercé
Hugues
H
Chap
Jean-Pierre
JP
Salles
Marie-Françoise
MF
Simon
Frédérique
F
Gaits
D017209:Apoptosis / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D002518:Ceramides / Q000494:pharmacology; D002798:Diacylglycerol Cholinephosphotransferase / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D037341:Fumonisins / Q000494:pharmacology; D006801:Humans; D008244:Lysophosphatidylcholines / Q000494:pharmacology; D008246:Lysophospholipids / Q000494:pharmacology; D048055:Mitogen-Activated Protein Kinase 8; D048056:Mitogen-Activated Protein Kinase 9; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000378:metabolism; D009646:Norleucine / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology*; D009687:Nuclear Proteins / Q000187:drug effects / Q000235:genetics; D010755:Organophosphates / Q000737:chemistry / Q000494:pharmacology*; D010713:Phosphatidylcholines / Q000096:biosynthesis*; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000235:genetics; D043562:Receptors, G-Protein-Coupled; D049368:Receptors, Lysophosphatidic Acid; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D014157:Transcription Factors / Q000187:drug effects / Q000235:genetics; D048051:p38 Mitogen-Activated Protein Kinases
D002518:Ceramides; D004791:Enzyme Inhibitors; D037341:Fumonisins; D008244:Lysophosphatidylcholines; D008246:Lysophospholipids; C470244:N-palmitoylnorleucinol 1-phosphate; D009687:Nuclear Proteins; D010755:Organophosphates; D010713:Phosphatidylcholines; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D049368:Receptors, Lysophosphatidic Acid; D014157:Transcription Factors; C056933:fumonisin B1; D009646:Norleucine; D048056:Mitogen-Activated Protein Kinase 9; D048055:Mitogen-Activated Protein Kinase 8; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D002798:Diacylglycerol Cholinephosphotransferase