De Petrocellis L, Melck D, Palmisano A, Bisogno T, Laezza C, Bifulco M, Di Marzo V
Istituto di Cibernetica, Consiglio Nazionale delle Ricerche), Consiglio Nazionale delle Ricerche, Via Toiano 6, 80072 Arco Felice, Naples, Italy.
Proc Natl Acad Sci U S A. 1998 Jul 7;95(14):8375-80. doi: 10.1073/pnas.95.14.8375.
Anandamide was the first brain metabolite shown to act as a ligand of "central" CB1 cannabinoid receptors. Here we report that the endogenous cannabinoid potently and selectively inhibits the proliferation of human breast cancer cells in vitro. Anandamide dose-dependently inhibited the proliferation of MCF-7 and EFM-19 cells with IC50 values between 0.5 and 1.5 microM and 83-92% maximal inhibition at 5-10 microM. The proliferation of several other nonmammary tumoral cell lines was not affected by 10 microM anandamide. The anti-proliferative effect of anandamide was not due to toxicity or to apoptosis of cells but was accompanied by a reduction of cells in the S phase of the cell cycle. A stable analogue of anandamide (R)-methanandamide, another endogenous cannabinoid, 2-arachidonoylglycerol, and the synthetic cannabinoid HU-210 also inhibited EFM-19 cell proliferation, whereas arachidonic acid was much less effective. These cannabimimetic substances displaced the binding of the selective cannabinoid agonist [3H]CP 55, 940 to EFM-19 membranes with an order of potency identical to that observed for the inhibition of EFM-19 cell proliferation. Moreover, anandamide cytostatic effect was inhibited by the selective CB1 receptor antagonist SR 141716A. Cell proliferation was arrested by a prolactin mAb and enhanced by exogenous human prolactin, whose mitogenic action was reverted by very low (0.1-0.5 microM) doses of anandamide. Anandamide suppressed the levels of the long form of the prolactin receptor in both EFM-19 and MCF-7 cells, as well as a typical prolactin-induced response, i.e., the expression of the breast cancer cell susceptibility gene brca1. These data suggest that anandamide blocks human breast cancer cell proliferation through CB1-like receptor-mediated inhibition of endogenous prolactin action at the level of prolactin receptor.
花生四烯乙醇胺是首个被证明作为“中枢”CB1大麻素受体配体的脑代谢物。在此我们报告，内源性大麻素在体外能有效且选择性地抑制人乳腺癌细胞的增殖。花生四烯乙醇胺呈剂量依赖性地抑制MCF - 7和EFM - 19细胞的增殖，IC50值在0.5至1.5微摩尔之间，在5至10微摩尔时最大抑制率达83 - 92%。10微摩尔的花生四烯乙醇胺对其他几种非乳腺肿瘤细胞系的增殖没有影响。花生四烯乙醇胺的抗增殖作用并非由于细胞毒性或凋亡，而是伴随着细胞周期S期细胞数量的减少。花生四烯乙醇胺的一种稳定类似物（R）-甲基花生四烯酸乙醇胺、另一种内源性大麻素2 - 花生四烯酸甘油酯以及合成大麻素HU - 210也抑制EFM - 19细胞增殖，而花生四烯酸的效果则差得多。这些类大麻物质以与抑制EFM - 19细胞增殖所观察到的效力顺序相同的方式，取代了选择性大麻素激动剂[3H]CP 55,940与EFM - 19细胞膜的结合。此外，花生四烯乙醇胺的细胞生长抑制作用被选择性CB1受体拮抗剂SR 141716A所抑制。细胞增殖被催乳素单克隆抗体阻断，而外源性人催乳素可增强细胞增殖，其促有丝分裂作用可被极低剂量（0.1 - 0.5微摩尔）的花生四烯乙醇胺逆转。花生四烯乙醇胺抑制了EFM - 19和MCF - 7细胞中催乳素受体长形式的水平，以及一种典型的催乳素诱导反应，即乳腺癌细胞敏感性基因brca1的表达。这些数据表明，花生四烯乙醇胺通过CB1样受体介导的对催乳素受体水平内源性催乳素作用的抑制来阻断人乳腺癌细胞的增殖。
