STAT3是癌细胞生存信号通路中的关键分子，是目前国际上高度关注的抗癌药物新靶标。本课题组前期研究发现，北美海蓬子中30-降齐墩果烷型三萜皂苷Bigelovii A既具有显著的体内外抗肝癌活性，还是一种新型的STAT3抑制剂，而且北美海蓬子和盐角草中都含有此类降三萜皂苷。本项目拟运用UPLC/DAD/Q-TOF/MS技术快速发现并靶向分离北美海蓬子和盐角草中降三萜皂苷成分，评价其抑制STAT3活性和抗肝癌作用，选择活性强毒性小的皂苷作为先导化合物，并重点研究该化合物对STAT3转位、结合DNA、反式激活的作用，对STAT3五种磷酸激酶（JAK、Src、ERK、JNK、p38）和一种磷酸酶（SHP-1）的作用，以及JAK-STAT信号通路在此皂苷诱导线粒体途径凋亡中的作用，从而为寻找和开发出靶点清楚、机制明确的新型抗肝癌药物奠定科学基础，为盐角草属植物的深度开发利用提供理论支持。

The signal transducer and activator of transcription 3 (STAT3) is a kind of important signal transduction protein in cells. Since this protein is closely related with the occurrence and development of the tumors, inhibiting STAT3 activation can be used to fight against tumors. Our group first reported that Bigelovii A, the new nortriterpenoid glycosides isolated from Salicornia bigelovii Torr., had eminent anti-tumor activity both in vitro and in vivo. Furthermore, BA can inhibit STAT3 phosphorylation, induce mitochondria mediated apoptosis. We also found these nortriterpenoid glycosides not only existed in Salicornia bigelovii Torr., but also existed in Salicornia europaea. In the project, we use variety of modern chromatography separation technologies, combined with UPLC/DAD/Q-TOF/MS, to isolate nortriterpenoid glycosides from Salicornia bigelovii Torr. and Salicornia europaea. Then we investigate their antitumor activity and their effect on STAT3 phosphorylation to choose the lead compound. Furthermore, we will research its effects not only on the nuclear translocation, DNA binding of STAT3, STAT3-dependent reporter gene expression, but also on five STAT3 kinases (JAK, Src, ERK, JNK, p38) and one STAT3 phosphatase (SHP-1). By the project, we will illuminate the anti-cancer mechanism induced by the representational nortriterpenoid glycoside, which will be beneficial to the new drug research and the utilization of the two halophytes, Salicornia bigelovii Torr. and Salicornia europaea.

乳腺癌是女性人群中发病率居首位的恶性肿瘤，全国肿瘤登记中心2015年年报显示中国女性乳腺癌年发病人数约24.9万，近10年来发病一直呈上升趋势。因此，寻找安全有效的抗乳腺癌药物具有十分重要的意义。降三萜类化合物结构新奇，生物活性显著，是当今世界天然产物化学的研究热点。本项目运用UPLC/DAD/Q-TOF/MS技术，结合降三萜类化合物的质谱特点，从盐生植物海蓬子和盐角草中分离得到降三萜皂苷类化合物10个，三萜皂苷类化合物14个，其中新降三萜皂苷2个；对量大的21个皂苷进行抗肿瘤活性筛选，发现2个活性较好的降三萜皂苷，海蓬子皂苷甲和海蓬子皂苷乙。构效分析发现C3位葡萄糖醛酸酯化，尤其是丁基酯化，是这类三萜皂苷细胞毒作用的关键；C28羧基也是这类三萜皂苷细胞毒作用的必需基团；C23位为甲基时细胞毒作用优于醛基。STAT3、NF-κB、mTOR是癌细胞生存信号通路中的关键分子，是目前国际上高度关注的抗癌药物新靶标。本项目采用凝胶迁移阻滞实验（EMSA）、免疫印迹、流式细胞仪等技术，结果发现海蓬子皂苷甲可通过抑制IKK激酶的活化从而抑制NF-κB磷酸化、NF-κB转位入核以及NF-κB与靶DNA的结合；通过激活酪氨酸磷酸酶SHP-1和SHP-2从而抑制IL6诱导的STAT3磷酸化和转位，从而降低下游靶基因Bcl-2、Bcl-xl、COX-2和Cyclin D1的表达，诱导肿瘤细胞凋亡和细胞周期阻滞；海蓬子皂苷甲还可通过抑制Akt和p-ERK蛋白表达，从而抑制mTOR及其下游通路激活，诱导细胞自噬水平的提高；同时，海蓬子皂苷甲通过抑制NF-κB、p38 MAPK/ERK1/2、炎性介质信号通路，从而减弱LPS诱导的急性肺损伤。本项目的完成，初步解析了海蓬子皂苷甲药效作用的分子机制，有利于北美海蓬子及野生盐角草资源的深度开发利用，提高相关产品的附加值。