东莨菪亭(7-羟基-6-甲氧基香豆素)对7 ,12-二甲基苯并蒽诱导的皮肤乳头状瘤小鼠相关关键信号蛋白的影响(英文)

Anti-oncogenic potentials of a plant coumarin (7-hydroxy-6-methoxy coumarin) against 7,12-dimethylbenz[a]anthracene-induced skin papilloma in mice:the possible role of several key signal proteins

目的:东莨菪亭(7-羟基-6-甲氧基香豆素)是从常绿钩吻中提取的有效成分,前期体外研究证实了其抗肿瘤潜能,本研究评价其在小鼠体内的抗肿瘤作用。方法:30只健康小鼠随机分为正常对照组、模型组、溶剂对照组和低、高剂量东莨菪亭组,每组6只。正常对照组小鼠不接受任何干预,其余小鼠背部涂抹100μg 7 ,12-二甲基苯并蒽(7 ,12-di methylbenz[a]anthra-cene ,DMBA)(每周一次)和1 %巴豆油(每周2次)诱导皮肤乳头状瘤,共24周。溶剂组小鼠在造模基础上每天予2 %酒精口服,低剂量(50 mg/kg)和高剂量(100 mg/kg)东莨菪亭组小鼠每天予东莨菪亭治疗。治疗24周后,检测碱性磷酸酶、超氧化物歧化酶、过氧化氢酶、谷胱甘肽过氧化物酶和谷胱甘肽S-转移酶活性;信号蛋白及其受体,包括芳香烃受体(Aryl hydrocarbon receptor , AhR)、p53、细胞色素P450亚酶1A1(cytochrome P450 1A1 , CYP1A1)、增殖细胞核抗原(proliferating cell nuclear antigen,PCNA)、信号转导和转录激活因子3(signal transducer and activator of transcription-3 ,Stat-3)、存活素、金属基质蛋白酶2、cyclin D1、c-myc、金属蛋白酶组织抑制因子2和半胱氨酸蛋白酶3(caspase-3) ,采用逆转录聚合酶链反应、蛋白印迹法或免疫沉淀法检测。结果:致癌物DMBA和巴豆油可以诱导毒性反应,生化指标中相关酶活性升高,AhR、CYP1A1、PCNA、Stat-3、存活素、MMP-2、cyclin D1和c-myc表达上调,p53、caspase-3和TI MP-2表达下调。荷瘤小鼠采用东莨菪亭治疗后,生化指标中相关酶的活性下降,蛋白表达和毒性生物标志物恢复正常。结论:东莨菪亭可能通过下调AhR表达来下调一些重要信号蛋白的表达,其作用机制可能是通过竞争性抑制存活素的表达。分裂原活化蛋白激酶可能也起到关键作用。东莨菪亭或许可作为化疗的替代药物用于治疗肿瘤。

Objective：Anti-cancer potentials of scopoletin （7-hydroxy-6-methoxy coumarin） separated from plant extract （Gelsemium sempervirens） were demonstrated earlier from our in vitro studies.In the present study,its in vivo effects have been evaluated in mice.Methods：Mice were chronically administered 7,12-dimethylbenz[a]anthracene （DMBA） once a week and croton oil twice a week on their back,which resulted in the development of fully grown finger-like projections （papilloma） after 24 weeks.Two subgroups of mice （drug-treated） were treated with two doses of scopoletin （50 mg and 100 mg/kg body weight） respectively while control received 2% ethyl alcohol （the ＂vehicle＂ of scopoletin）.After the 24-week drug administration,expressions of several key receptors such as aryl hydrocarbon receptor （AhR） and signal proteins like p53,cytochrome P450 1A1 （CYP1A1）,proliferating cell nuclear antigen （PCNA）,signal transducer and activator of transcription-3 （Stat-3）,survivin,matrix metalloproteinase-2 （MMP-2）,cyclin D1,c-myc,tissue inhibitor of matrix metalloproteinase-2 （TIMP-2） and caspase-3,and some anti-oxidant markers were studied.Lipid peroxidation,superoxide dismutase,catalase,glutathione peroxidase and glutathione-s-transferase in supernatant were also detected.Results：Carcinogens induced toxicity,and over-expression of AhR,CYP1A1,PCNA,Stat-3,survivin,MMP-2,cyclin D1 and c-myc and down-regulation of p53,caspase-3 and TIMP-2.In mice treated with scopoletin,the expressions of these proteins and toxicity biomarkers were reverted.Conclusion：Since AhR is known to be ligand-activated by DMBA to release signals for several downstream proteins initiating reactive oxygen species generation,the down-regulation of AhR by scopoletin appeared to play a significant role in subsequent down-regulation of some key signal proteins.One possible mechanism of down-regulation of AhR may be through competitive inhibition by scopoletin.Mitogen-activated protein kinases may also have some critical role.This compound can be considered as a possible candidate for chemoprevention.