基于NF-κB研究赣南中草药乌苏烷型三萜类抗肿瘤活性成分

As a new therapeutic target in tumor treatment, NF-κB signaling pathway had been the research focus in recent years. It had a wide application prospect screening for selective NF-κB inhibitor as antitumor drugs from abundant Chinese medicine resources. Six ursane triterenoids had been isolated and identified from Gannan hebal medicine through the preliminary research, among which compound Ilexgenin A(IA) was with antitumor activity and could inhibit the expression level of NF-κB. Based on the previous chemical and biological researches, this project would continue the directional separation of characteristic ursane triterenoids from Chinese medicine resources in Gannan region. And the target compound with obvious NF-κB inhibition activity would be selected to study their tumor inhibition activity and mechanisms from the levels of molecule, cell and animal by MTT(4-methyl thiazolyl tetrazolium) assay, FCM (flow cytometry), method of immunocytechemistry, EMSA (electrophoretic mobility shift assay ),Western blotting and RT-PCR(reverse transcription-polymerase chain reaction). The final target of this project was to obtain antitumor lead compounds with potential medical value. This research would provide reference not only for reasonable exploitation and utilization of Chinese medicine resources in Gannan region, but also for the development of antitumor drug NF-κB inhibitors.

项目组前期研究从赣南中草药中分离得到6个乌苏烷三萜类化合物，其中具有抗肿瘤活性的化合物IA可抑制NF-κB表达水平。近年来NF-κB信号途径作为肿瘤治疗的靶点引起人们的高度关注，从资源丰富的中草药中寻找和发现具选择性的NF-κB抑制类抗肿瘤药物具有广阔的应用前景。故本项目拟在前期化学和生物学研究的工作基础上，继续从赣南地区资源丰富的中草药中定向分离特征性的乌苏烷三萜类，选择具有明显NF-κB抑制活性的目标化合物为研究对象，并采用MTT、FCM、免疫组化法、Westen blot、EMSA、RT-PCR等实验方法从分子水平、细胞水平、动物水平三个层次对该类化合物进行靶向NF-κB抑制抗肿瘤活性筛选和作用机制研究，以期获得具有潜在药用价值的抗肿瘤活性先导化合物。本课题的开展将为合理开发利用江西省赣南地区中草药资源积累资料，为NF-κB抑制类抗肿瘤药物的研究开发提供一定的科学依据。

NF-κB信号途径作为肿瘤治疗的靶点已引起人们的高度关注，从赣南地区资源丰富的中草药中寻找和发现具选择性的NF-κB抑制类抗肿瘤药物具有广阔的应用前景。本项目主要采用MTT、FCM、免疫组化法、Westen blot、EMSA、RT-PCR等实验方法从分子水平、细胞水平、动物水平三个层次对从山绿茶Ilex hainanensis Merr.、藤梨根（中华猕猴桃根Actinidia chinensis Radix）、对萼猕猴桃根Actinidia valvata Dunn.Radix等中草药中分离得到的三个乌苏烷类化合物Ilexgenin A（IA），2β, 3β, 23-trihydroxy-urs-12-ene-28-olic acid (TUA)，Corosolic acid（CRA）进行靶向NF-κB抑制抗肿瘤活性筛选和作用机制研究。结果表明，IA具有诱导HeLa细胞凋亡的作用，其机制可能与激活Caspase-3/7和抑制NF-κB蛋白表达有关；TUA对肺癌NCI-H460细胞的增殖抑制作用与其抑制NF-κB信号通路有关；体内实验结果进一步证实TUA能显著抑制肺癌移植瘤的生长，其机制可能与抑制肿瘤组织中凋亡相关蛋白p65,Survivin表达和上调IκBα, Caspase-3蛋白的表达相关；CRA 能降低胃癌BGC823细胞内p65, bcl-2, Fas, smac蛋白及基因表达水平，增加IκBα, bax, survivin蛋白及基因表达水平，免疫荧光染色及EMSA实验结果进一步证明了CRA能够通过抑制p65核移位从而诱导胃癌细胞凋亡，说明CRA对胃癌BGC823细胞的诱导凋亡作用与其抑制NF-κB表达、增加IκBα表达水平有关。本课题的开展为合理开发利用江西省赣南地区中草药资源积累资料，为NF-κB抑制类抗肿瘤药物的研究开发提供了一定的科学依据。