Izzo Angelo A, Aviello Gabriella, Petrosino Stefania, Orlando Pierangelo, Marsicano Giovanni, Lutz Beat, Borrelli Francesca, Capasso Raffaele, Nigam Santosh, Capasso Francesco, Di Marzo Vincenzo
Department of Experimental Pharmacology, University of Naples Federico II, Naples, Italy.
J Mol Med (Berl). 2008 Jan;86(1):89-98. doi: 10.1007/s00109-007-0248-4. Epub 2007 Sep 6.
Colorectal cancer is an increasingly important cause of death in Western countries. Endocannabinoids inhibit colorectal carcinoma cell proliferation in vitro. In this paper, we investigated the involvement of endocannabinoids on the formation of aberrant crypt foci (ACF, earliest preneoplastic lesions) in the colon mouse in vivo. ACF were induced by azoxymethane (AOM); fatty acid amide hydrolase (FAAH) and cannabinoid receptor messenger ribonucleic acid (mRNA) levels were analyzed by the quantitative reverse transcription polymerase chain reaction (RT-PCR); endocannabinoid levels were measured by liquid chromatography-mass spectrometry; caspase-3 and caspase-9 expressions were measured by Western blot analysis. Colonic ACF formation after AOM administration was associated with increased levels of 2-arachidonoylglycerol (with no changes in FAAH and cannabinoid receptor mRNA levels) and reduction in cleaved caspase-3 and caspase-9 expression. The FAAH inhibitor N-arachidonoylserotonin increased colon endocannabinoid levels, reduced ACF formation, and partially normalized cleaved caspase-3 (but not caspase-9) expression. Notably, N-arachidonoylserotonin completely prevented the formation of ACF with four or more crypts, which have been show to be best correlated with final tumor incidence. The effect of N-arachidonoylserotonin on ACF formation was mimicked by the cannabinoid receptor agonist HU-210. No differences in ACF formation were observed between CB(1) receptor-deficient and wild-type mice. It is concluded that pharmacological enhancement of endocannabinoid levels (through inhibition of endocannabinoid hydrolysis) reduces the development of precancerous lesions in the mouse colon. The protective effect appears to involve caspase-3 (but not caspase-9) activation.
在西方国家，结直肠癌正成为一个日益重要的死亡原因。内源性大麻素在体外可抑制结肠癌细胞增殖。在本文中，我们研究了内源性大麻素在体内对小鼠结肠异常隐窝灶（ACF，最早的癌前病变）形成的影响。ACF由氧化偶氮甲烷（AOM）诱导产生；通过定量逆转录聚合酶链反应（RT-PCR）分析脂肪酸酰胺水解酶（FAAH）和大麻素受体信使核糖核酸（mRNA）水平；通过液相色谱-质谱法测量内源性大麻素水平；通过蛋白质免疫印迹分析测量半胱天冬酶-3和半胱天冬酶-9的表达。给予AOM后结肠ACF的形成与2-花生四烯酸甘油水平升高（FAAH和大麻素受体mRNA水平无变化）以及裂解的半胱天冬酶-3和半胱天冬酶-9表达降低有关。FAAH抑制剂N-花生四烯酰基血清素可提高结肠内源性大麻素水平，减少ACF形成，并使裂解的半胱天冬酶-3（而非半胱天冬酶-9）表达部分恢复正常。值得注意的是，N-花生四烯酰基血清素完全阻止了具有四个或更多隐窝的ACF的形成，而这些ACF已被证明与最终肿瘤发生率最相关。大麻素受体激动剂HU-210模拟了N-花生四烯酰基血清素对ACF形成的影响。在CB(1)受体缺陷型小鼠和野生型小鼠之间未观察到ACF形成的差异。得出的结论是，通过抑制内源性大麻素水解来药理增强内源性大麻素水平可减少小鼠结肠癌前病变发展。这种保护作用似乎涉及半胱天冬酶-3（而非半胱天冬酶-9）的激活。
