Inhibition of HMG-CoA reductase activity and of Ras farnesylation mediate antitumor effects of anandamide in human breast cancer cell.

The endocannabinoid system regulates cell proliferation in human breast cancer cells. Recently, we described that a metabolically stable anandamide analogue, 2-methyl-2'-F-anandamide, by activation of CB1 receptors significantly inhibited cell proliferation of human breast cancer cell lines. In this study, we observed that the activation of the CB1 receptor, in two human mammary carcinoma cell lines, MDA MB 231 and MCF7,caused the inhibition of 3-hydroxy-3-methylglutaryl (HMG)-coenzyme A (CoA)-reductase activity due to a reduction of HMG-CoA reductase transcript levels. The decrease of HMG-CoA reductase activity induced the inhibition of the prenylation of proteins, in particular of the farnesylation of Ras oncogenic protein involved in cell proliferation of these cell lines. We suggest that the inhibitory effect of anadamide analogue on tumor cell proliferation could be related to the inhibition of Ras farnesylation.