Activation of phosphoinositide 3-kinase/PKB pathway by CB(1) and CB(2) cannabinoid receptors expressed in prostate PC-3 cells. Involvement in Raf-1 stimulation and NGF induction.
Cannabinoids exert a variety of physiological and pharmacological responses in humans through interaction with specific cannabinoid receptors. Cannabinoid receptors described to date belong to the seven-transmembrane-domain receptor superfamily and are coupled through the inhibitory G(i) protein to adenylyl cyclase inhibition. However, downstream signal transduction mechanisms triggered by cannabinoids are poorly understood. We examined here the involvement of the phosphoinositide 3-kinase (PI3K)/PKB pathway in the mechanism of action of cannabinoids in human prostate epithelial PC-3 cells. Cannabinoid receptors CB(1) and CB(2) are expressed in these cells, as shown by RT-PCR, Western blot and immunofluorescence techniques. Treatment of PC-3 cells with either Delta(9)-tetrahydrocannabinol (THC), the major psychoactive ingredient of marijuana, or R-(+)-methanandamide (MET), an analogue of the endogenous cannabinoid anandamide, increased phosphorylation of PKB in Thr308 and Ser473. The stimulation of PKB induced by cannabinoids was blocked by the two cannabinoid receptor antagonists, SR 141716 and SR 144528, and by the PI3K inhibitor LY 294002. These results indicate that activation of cannabinoid receptors in PC-3 cells stimulate the PI3K/PKB pathway. We further investigated the involvement of Raf-1/Erk activation in the mechanism of action of cannabinoid receptors. THC and MET induced translocation of Raf-1 to the membrane and phosphorylation of p44/42 Erk kinase, which was reversed by cannabinoid receptor antagonists and PI3K inhibitor. These results point to a sequential connection between cannabinoid receptors/PI3K/PKB pathway and Raf-1/Erk in prostate PC-3 cells. We also show that this pathway is involved in the mechanism of NGF induction exerted by cannabinoids in PC-3 cells.
Sánchez
María G
MG
Department of Biochemistry and Molecular Biology, School of Medicine, University of Alcalá, Alcalá de Henares, 28871 Madrid, Spain.
Ruiz-Llorente
Lidia
L
Sánchez
Ana M
AM
Díaz-Laviada
Inés
I
D064413:3-Phosphoinositide-Dependent Protein Kinases; D000818:Animals; D001095:Arachidonic Acids / Q000494:pharmacology; D015152:Blotting, Northern; D015153:Blotting, Western; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor / Q000187:drug effects / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002531:Cerebellum / Q000737:chemistry; D002867:Chromones / Q000494:pharmacology; D013759:Dronabinol / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D005786:Gene Expression Regulation; D006801:Humans; D008099:Liver / Q000737:chemistry; D008214:Lymphocytes / Q000378:metabolism; D008297:Male; D008856:Microscopy, Fluorescence; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000502:physiology; D009025:Morpholines / Q000494:pharmacology; D020932:Nerve Growth Factor / Q000378:metabolism*; D016716:PC12 Cells; D010766:Phosphorylation / Q000187:drug effects; D010880:Piperidines / Q000494:pharmacology; D016133:Polymerase Chain Reaction; D011467:Prostate / Q000378:metabolism / Q000473:pathology; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000187:drug effects / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D019908:Proto-Oncogene Proteins c-raf / Q000187:drug effects / Q000502:physiology*; D011720:Pyrazoles / Q000494:pharmacology; D051381:Rats; D043884:Receptor, Cannabinoid, CB1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D043885:Receptor, Cannabinoid, CB2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000077285:Rimonabant; D015398:Signal Transduction / Q000187:drug effects; D013154:Spleen / Q000737:chemistry
D001095:Arachidonic Acids; D002867:Chromones; D005419:Flavonoids; D009025:Morpholines; D010880:Piperidines; D011518:Proto-Oncogene Proteins; D011720:Pyrazoles; D043884:Receptor, Cannabinoid, CB1; D043885:Receptor, Cannabinoid, CB2; C088155:methanandamide; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D013759:Dronabinol; D020932:Nerve Growth Factor; D064413:3-Phosphoinositide-Dependent Protein Kinases; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D019908:Proto-Oncogene Proteins c-raf; D020928:Mitogen-Activated Protein Kinases; D000077285:Rimonabant; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one