title: Inhibition of human tumour prostate PC-3 cell growth by cannabinoids R(+)-Methanandamide and JWH-015: involvement of CB2.
abstract: BACKGROUND
  We have previously shown that cannabinoids induce growth inhibition and apoptosis in prostate cancer PC-3 cells, which express high levels of cannabinoid receptor types 1 and 2 (CB(1) and CB(2)). In this study, we investigated the role of CB(2) receptor in the anti-proliferative action of cannabinoids and the signal transduction triggered by receptor ligation.
  
  
  METHODS
  The human prostate cancer cell lines, namely PC-3, DU-145 and LNCaP, were used for this study. Cell proliferation was measured using MTT proliferation assay, [(3)H]-thymidine incorporation assay and cell-cycle study by flow cytometry. Ceramide quantification was performed using the DAG kinase method. The CB(2) receptor was silenced with specific small interfering RNA, and was blocked pharmacologically with SR 144528. In vivo studies were conducted by the induction of prostate xenograft tumours in nude mice.
  
  
  RESULTS
  We found that the anandamide analogue, R(+)-Methanandamide (MET), as well as JWH-015, a synthetic CB(2) agonist, exerted anti-proliferative effects in PC-3 cells. R(+)-Methanandamide- and JWH-015-induced cell death was rescued by treatment with the CB(2) receptor antagonist, SR 144528. Downregulation of CB(2) expression reversed the effects of JWH-015, confirming the involvement of CB(2) in the pro-apoptotic effect of cannabinoids. Further analysing the mechanism of JWH-015-induced cell growth inhibition, we found that JWH-015 triggered a de novo synthesis of ceramide, which was involved in cannabinoid-induced cell death, insofar as blocking ceramide synthesis with Fumonisin B1 reduced cell death. Signalling pathways activated by JWH-015 included JNK (c-Jun N-terminal kinase) activation and Akt inhibition. In vivo treatment with JWH-015 caused a significant reduction in tumour growth in mice.
  
  
  CONCLUSIONS
  This study defines the involvement of CB(2)-mediated signalling in the in vivo and in vitro growth inhibition of prostate cancer cells and suggests that CB(2) agonists have potential therapeutic interest and deserve to be explored in the management of prostate cancer.
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Medicine, University of Alcalá, Alcalá de Henares, 28871 Madrid, Spain.
authors.forename: N
authors.initials: N
authors.lastname: Olea-Herrero
authors.forename: D
authors.initials: D
authors.lastname: Vara
authors.forename: S
authors.initials: S
authors.lastname: Malagarie-Cazenave
authors.forename: I
authors.initials: I
authors.lastname: Díaz-Laviada
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001095:Arachidonic Acids / Q000494:pharmacology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002518:Ceramides / Q000096:biosynthesis; D006801:Humans; D007211:Indoles / Q000494:pharmacology*; D008297:Male; D051379:Mice; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000473:pathology; D043885:Receptor, Cannabinoid, CB2 / Q000502:physiology*; D015398:Signal Transduction; D023041:Xenograft Model Antitumor Assays
chemical_list: D001095:Arachidonic Acids; D002518:Ceramides; D007211:Indoles; D043885:Receptor, Cannabinoid, CB2; C088155:methanandamide; C402944:JHW 015
references.citation: Life Sci. 2005 Aug 19;77(14):1723-31
references.pmid: 15958274
references.citation: J Biol Chem. 2006 Dec 22;281(51):39480-91
references.pmid: 17068343
references.citation: Prostate. 2003 Feb 1;54(2):95-102
references.pmid: 12497582
references.citation: Mol Ther. 2009 Mar;17(3):430-8
references.pmid: 19107118
references.citation: Mini Rev Med Chem. 2005 Jan;5(1):97-106
references.pmid: 15638794
references.citation: Cancer Res. 2008 Jan 15;68(2):339-42
references.pmid: 18199524
references.citation: J Clin Invest. 2009 May;119(5):1359-72
references.pmid: 19425170
references.citation: Trends Pharmacol Sci. 2001 Jan;22(1):19-22
references.pmid: 11165667
references.citation: Biochem Pharmacol. 2009 Jan 1;77(1):86-100
references.pmid: 18848818
references.citation: Cancer Res. 2005 Mar 1;65(5):1635-41
references.pmid: 15753356
references.citation: Toxicol Appl Pharmacol. 2008 Sep 15;231(3):282-90
references.pmid: 18556036
references.citation: Nat Rev Mol Cell Biol. 2008 Jul;9(7):532-42
references.pmid: 18568041
references.citation: Recent Pat Anticancer Drug Discov. 2006 Nov;1(3):369-82
references.pmid: 18221047
references.citation: Curr Med Chem. 2006;13(14):1609-16
references.pmid: 16787207
references.citation: Prostate. 2003 Jun 15;56(1):1-12
references.pmid: 12746841
references.citation: J Neuroendocrinol. 2008 May;20 Suppl 1:10-4
references.pmid: 18426493
references.citation: J Urol. 2007 Oct;178(4 Pt 1):1148
references.pmid: 17698142
references.citation: Sci STKE. 2007 Jul 10;2007(394):jc1
references.pmid: 17622645
references.citation: Curr Med Chem. 2008;15(14):1428-43
references.pmid: 18537620
references.citation: Cancer Res. 2006 Jul 1;66(13):6748-55
references.pmid: 16818650
references.citation: Biochim Biophys Acta. 2009 Jan;1792(1):3-13
references.pmid: 19022377
references.citation: Cancer Lett. 2008 Jun 8;264(1):1-10
references.pmid: 18353542
references.citation: Apoptosis. 2007 Nov;12(11):2013-24
references.pmid: 17828457
references.citation: Clin Cancer Res. 2008 Dec 1;14(23):7691-700
references.pmid: 19047095
references.citation: Pharmacol Biochem Behav. 2008 Oct;90(4):501-11
references.pmid: 18584858
references.citation: Life Sci. 2006 Jan 2;78(6):549-63
references.pmid: 16109430
references.citation: Dialogues Clin Neurosci. 2007;9(4):413-30
references.pmid: 18286801
references.citation: Trends Pharmacol Sci. 2007 Jan;28(1):39-45
references.pmid: 17141334
references.citation: FEBS Lett. 1999 Sep 24;458(3):400-4
references.pmid: 10570948
references.citation: Methods Mol Biol. 2008;414:191-220
references.pmid: 18175821
references.citation: Methods Enzymol. 2000;312:22-31
references.pmid: 11070860
references.citation: Cancer Cell. 2006 Apr;9(4):301-12
references.pmid: 16616335
references.citation: Mol Neurobiol. 2007 Aug;36(1):60-7
references.pmid: 17952650
references.citation: Cancer Biol Ther. 2009 Jan;8(1):64-5
references.pmid: 19127120
references.citation: Semin Cancer Biol. 2008 Jun;18(3):176-89
references.pmid: 18249558
references.citation: Mol Pharmacol. 1998 Nov;54(5):834-43
references.pmid: 9804618
references.citation: Cancer Res. 2006 Jul 1;66(13):6615-21
references.pmid: 16818634
references.citation: Best Pract Res Clin Endocrinol Metab. 2009 Feb;23(1):117-31
references.pmid: 19285265
references.citation: Apoptosis. 2006 Jan;11(1):89-99
references.pmid: 16374544
references.citation: Subcell Biochem. 2008;49:413-40
references.pmid: 18751921
references.citation: Adv Exp Med Biol. 2008;630:57-71
references.pmid: 18637485
references.citation: Apoptosis. 2004 Jul;9(4):423-7
references.pmid: 15192324
references.citation: Mol Cell Biol. 2009 Aug;29(16):4431-40
references.pmid: 19528225
references.citation: Nat Rev Cancer. 2003 Oct;3(10):745-55
references.pmid: 14570037
references.citation: Int J Obes (Lond). 2006 Apr;30 Suppl 1:S13-8
references.pmid: 16570099
references.citation: Mini Rev Med Chem. 2005 Jul;5(7):619-30
references.pmid: 16026308
references.citation: Exp Cell Res. 2006 Jul 1;312(11):2121-31
references.pmid: 16624285
references.citation: FEBS Lett. 2003 Dec 18;555(3):561-6
references.pmid: 14675774
references.citation: Br J Pharmacol. 2006 May;148(2):123-35
references.pmid: 16501583
references.citation: Cancer Res. 2001 Aug 1;61(15):5784-9
references.pmid: 11479216
references.citation: Cancer Res. 2008 Mar 15;68(6):1945-52
references.pmid: 18339876
references.citation: Pharmacol Res. 2003 May;47(5):383-92
references.pmid: 12676512
references.citation: Neuroscience. 2005;134(2):567-74
references.pmid: 15975726
references.citation: Biochem J. 2002 Apr 1;363(Pt 1):183-8
references.pmid: 11903061
references.citation: Endocr Relat Cancer. 2008 Jun;15(2):391-408
references.pmid: 18508995
references.citation: Mol Pharmacol. 2006 Nov;70(5):1612-20
references.pmid: 16936228