Carrasco-Legleu Claudia-Esther, Sánchez-Pérez Yesennia, Márquez-Rosado Lucrecia, Fattel-Fazenda Samia, Arce-Popoca Evelia, Hernández-García Sergio, Villa-Treviño Saúl
Departamento de Biología Celular, Laboratorio 50, Centro de Investigación y de Estudios Avanzados del IPN (Cinvestav). Ave. IPN #2508. Col. San Pedro Zacatenco, C.P. 07360, México, D.F., México.
World J Gastroenterol. 2006 Nov 14;12(42):6779-85. doi: 10.3748/wjg.v12.i42.6779.
To study of the effect of caffeic acid phenethyl ester (CAPE) on the initiation period in a medium-term assay of hepatocarcinogenesis.
Male Wistar rats were subjected to a carcinogenic treatment (CT) and sacrificed at 25th d; altered hepatic foci (AHF) were generated efficiently. To a second group of rats a single 20 mg/kg doses of CAPE was given 12 h before initiation with CT and were sacrificed at 25th d. We evaluated the expression of preneoplastic markers as gamma-glutamyltranspeptidase (GGT) and glutathione S-transferase type pi protein (GSTp) by histochemistry, RT-PCR and Western blot analyses, respectively. We measured thiobarbituric acid reactive substances (TBARS) in homogenates of liver and used Unscheduled DNA Synthesis (UDS) assay by incorporation of [3H] thymidine (3HdT) in primary hepatocyte cultures (PHC).
At 25th d after CT CAPE reduced the observed increase of GGT+AHF by 84% and liver expression of ggt mRNA by 100%. In case of the GSTp protein, the level was reduced by 90%. As indicative of oxidative stress generated by diethylnitrosamine (DEN) 12 h after its administration, we detected a 68% increase of TBARS. When CAPE was administered before DEN, it completely protected from liver TBARS induction. To have an indication of the sole effect of CAPE on initiation, two carcinogens were tested in a UDS assay in PHC, we used methyl-n-nitrosoguanidine as a direct carcinogen and DEN, as indirect carcinogen. In this assay, genotoxic damage caused by carcinogens was abolished at 5 microM CAPE concentration.
Our results demonstrated that CAPE possesses anti-genotoxic and antineoplastic capabilities, by an anti-oxidative and free-radical scavenging mechanism.
在肝癌发生中期试验中研究咖啡酸苯乙酯（CAPE）对起始阶段的影响。
对雄性Wistar大鼠进行致癌处理（CT），并在第25天处死；有效诱导产生了肝灶性病变（AHF）。对第二组大鼠在进行CT起始处理前12小时给予单次20mg/kg剂量的CAPE，并在第25天处死。我们分别通过组织化学、逆转录聚合酶链反应（RT-PCR）和蛋白质免疫印迹分析评估了癌前标志物γ-谷氨酰转肽酶（GGT）和π型谷胱甘肽S-转移酶蛋白（GSTp）的表达。我们测量了肝脏匀浆中的硫代巴比妥酸反应性物质（TBARS），并通过在原代肝细胞培养物（PHC）中掺入[3H]胸腺嘧啶核苷（3HdT）进行非程序性DNA合成（UDS）试验。
CT处理后第25天，CAPE使观察到的GGT+AHF增加减少了84%，ggt mRNA的肝脏表达减少了100%。就GSTp蛋白而言，其水平降低了90%。作为二乙基亚硝胺（DEN）给药后12小时产生的氧化应激的指标，我们检测到TBARS增加了68%。当在DEN之前给予CAPE时，它完全保护肝脏免受TBARS诱导。为了了解CAPE对起始阶段的单独作用，在PHC的UDS试验中测试了两种致癌物，我们使用甲基-n-亚硝基胍作为直接致癌物，DEN作为间接致癌物。在该试验中，在5μM CAPE浓度下，致癌物引起的遗传毒性损伤被消除。
我们的结果表明CAPE通过抗氧化和自由基清除机制具有抗遗传毒性和抗肿瘤能力。
