title: Anticancer activity of anandamide in human cutaneous melanoma cells.
abstract: Cannabinoids are implicated in the control of cell proliferation, but little is known about the role of the endocannabinoid system in human malignant melanoma. This study was aimed at characterizing the in vitro antitumor activity of anandamide (AEA) in A375 melanoma cells. The mRNA expression of genes that code for proteins involved in the metabolism and in the mechanism of AEA action was assessed by RT-PCR. Cell viability was tested using WST-1 assay and the apoptotic cell death was determined by measuring caspase 3/7 activities. A375 cells express high levels of fatty acid amide hydrolase (FAAH), cyclooxygenase (COX)-2, cannabinoid receptor 1 (CB1), transient receptor potential cation channel subfamily V member 1 (TRPV1) and G-protein-coupled receptor 55 (GPR55) genes. AEA induced a concentration-dependent cytotoxicity with an IC50 of 5.8 ± 0.7 µM and such an effect was associated to a caspase-dependent apoptotic pathway. AEA cytotoxicity was potentiated by FAAH inhibition (2-fold increase, p<0.05) and mitigated by COX-2 or lipoxygenase (LOX) inhibition (5- and 3-fold decrease, respectively; p<0.01). Blocking CB1 receptors partially decreased AEA cytotoxicity, whereas selective antagonism on the TRPV1 barely affected the mechanism of AEA action. Finally, methyl-β-cyclodextrin, a membrane cholesterol depletory, completely reversed the cytotoxicity induced by the selective GPR55 agonist, O-1602, and AEA. Overall, these findings demonstrate that AEA induces cytotoxicity against human melanoma cells in the micromolar range of concentrations through a complex mechanism, which involves COX-2 and LOX-derived product synthesis and CB1 activation. Lipid raft modulation, probably linked to GPR55 activation, might also have a role.
authors.affiliation: Department of Pharmacy, University of Pisa, Via Bonanno 6, 56100 Pisa, Italy. Electronic address: badinolfi@yahoo.it.
authors.forename: Barbara
authors.initials: B
authors.lastname: Adinolfi
authors.forename: Antonella
authors.initials: A
authors.lastname: Romanini
authors.forename: Alessia
authors.initials: A
authors.lastname: Vanni
authors.forename: Enrica
authors.initials: E
authors.lastname: Martinotti
authors.forename: Andrea
authors.initials: A
authors.lastname: Chicca
authors.forename: Stefano
authors.initials: S
authors.lastname: Fogli
authors.forename: Paola
authors.initials: P
authors.lastname: Nieri
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001095:Arachidonic Acids / Q000494:pharmacology*; D045744:Cell Line, Tumor; D063388:Endocannabinoids / Q000494:pharmacology*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008545:Melanoma / Q000473:pathology*; D053284:Polyunsaturated Alkamides / Q000494:pharmacology*; D043882:Receptors, Cannabinoid / Q000378:metabolism; D012878:Skin Neoplasms / Q000473:pathology*; D050916:TRPV Cation Channels / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D001095:Arachidonic Acids; D063388:Endocannabinoids; D053284:Polyunsaturated Alkamides; D043882:Receptors, Cannabinoid; D050916:TRPV Cation Channels; C494482:TRPV1 protein, human; C078814:anandamide
keywords: Anandamide; Apoptosis; Cytotoxicity; Endocannabinoid system; Melanoma