Figure 1

Enzymatic hydrolysis and cytotoxicity of AEA, 2-AG and PEA in B16 melanoma cells. (A) Enzymatic activities for AEA, 2-AG and PEA hydrolysis were measured in B16 cell homogenates using [³H]-AEA, [³H]-2-OG and [³H]-PEA, respectively. Data are the mean of three experiments performed in duplicate. (B) B16 cells express endocannabinoid degrading enzymes FAAH, NAAA and MAGL. Detection of mRNA was performed by RT-PCR using respectively mouse liver, lung and brain as control and RPL19 as house keeping gene (blot representative of three). (C) The endocannabinoids AEA, 2-AG and PEA decrease B16 cell viability. Cells were seeded 5 h before treatment (2000 cells/well in microwells) and incubated with 10 μM of endocannabinoids. After 24 h, 48 h or 72 h of treatment, cytotoxicity was assessed by a MTT test. Data are expressed as percentage of the vehicle control and are the mean of three experiments performed in quintuplicate. Significantly different (**P < 0.01) from vehicle incubation. (D) PEA dose-dependently decreases B16 cell viability. The cells were incubated with 1 μM, 10 μM and 20 μM of PEA. After 72 h of treatment, cytotoxicity was assessed by a MTT test. Data are expressed as percentage of the vehicle control and are the mean of three experiments performed in quintuplicate. Significantly different (**P < 0,01) from vehicle incubation. (E) Palmitic acid does not decrease B16 viability. The cells were incubated with 1 μM, 10 μM and 20 μM of palmitic acid. After 72 h of treatment, cytotoxicity was assessed by a MTT test. Data are expressed as percentage of the vehicle control and are the mean of three experiments performed in quintuplicate.