基于肿瘤微环境干预的重楼皂苷抗转移性肺癌作用机制及物质基础研究

Tumor metastasis is an important clinical issue for the malignant tumor treatment. Meanwhile, tumor microenvironment as the driving factor for the tumor metastasis, its intervention is pivotal to inhibiting the tumor metastasis. As we know, cell metabolism influences tumor microenvironment. At the same time, cisplatin and sorafenib promote tumor metastasis through the regulation of the tumor microenvironment. Rhizoma Paridis is regarded as a common herb and one of the main materials used in the anticancer Traditional Chinese medicine (TCM) prescription. Rhizoma Paridis Saponins (RPS) as its effective part shows multi-component, multi-target and strong inhibition of the pulmonary metastasis. Our preliminary experiments also indicated that combination of RPS and platinum enhanced efficacy and reduced toxicity of platinum. In order to prove the hypothesis that “RPS can act on the axis ‘tumor microenvironment-cell metabolism-signaling pathway’, and further enhance efficacy and reducing toxicity of cisplatin and sorafenib to inhibit the pulmonary metastasis”, we are going to set up 3 kinds of metastatic lung cancer models, evaluate the activity of RPS used alone or combined with chemotherapy, explore its material basis and analyze the mechanisms of its anti-metastatic lung cancer effects base on the tumor microenvironment intervention. All in all, this project will promote the clinical application of RPS, and enrich the pharmacological theory of TCM based on the targets on the tumor microenvironment to inhibit the metastatic lung cancer. Furthermore, it may serve as an indication for the safe medication and rational administration of the anticancer drugs such as cisplatin and sorafenib.

肿瘤转移是恶性肿瘤治疗的核心问题，而肿瘤微环境作为其驱动因素，它的调节是抑制肿瘤转移的关键。目前认为，细胞代谢可整体调控肿瘤微环境；同时顺铂、索拉非尼有通过改变微环境促转移的报道。我们的前期试验表明，中药重楼的活性成分重楼皂苷（RPS）具有多成分、多靶点性，可显著抑制转移性肺癌；预实验也显示RPS与铂类药联用有增效减毒的优势。为进一步证明“RPS可作用于‘肿瘤微环境-细胞代谢-信号通路’的信号轴，进而与顺铂、索拉非尼联用，可增效减毒发挥抗转移作用”的假说，本项目拟从转移性肺癌模型的建立、活性评价、药效物质基础研究到基于肿瘤微环境的机制探讨，全面分析RPS发挥抗转移作用的药效物质基础及作用机制；同时对比顺铂、索拉非尼等抗癌药，分析RPS与其联用的优势。总之，本项目的顺利实施将促进RPS的临床应用，丰富中药基于肿瘤微环境干预发挥抗转移作用的基础理论，同时为顺铂、索拉非尼的合理用药奠定理论依据。

本项目立项目的是为了证明“重楼皂苷（RPS）可作用于‘肿瘤微环境-细胞代谢-信号通路’的信号轴，进而与顺铂、索拉非尼联用，增效减毒发挥抗转移作用”的假说。项目从转移性肺癌模型的建立、活性评价、药效物质基础研究到基于肿瘤微环境的机制探讨，全面分析RPS发挥抗转移作用的药效物质基础及作用机制；同时对比顺铂、索拉非尼等抗癌药，分析RPS与其联用的优势。首先，组织分布实验证明RPS在重复给药后逐渐在肝、肺、脾等处蓄积，含量可达到比较高的水平，这为RPS用于肝癌、肺癌及相关疾病的治疗提供理论依据。随后采用荧光标记重楼皂苷VI的方式，观测重楼皂苷主要通过OATP1B1转运蛋白进入细胞，与内质网、线粒体、溶酶体等结合，诱发内质网应激及线粒体凋亡途径，并引发自噬，最终发挥抗肝癌作用。同时重楼皂苷Ⅱ还可诱导新的死亡途径——旁凋亡、铁死亡等，利用该途径可增敏顺铂的抗肿瘤活性。其次，课题组发现RPS中不同苷元母核的皂苷联用存在协同效能，以重楼皂苷Ⅱ和Ⅶ联合为例，二者联用显著高于单体的抗癌活性。其作用机制主要是通过重楼皂苷Ⅱ能激活细胞自噬，引发低剂量的自我保护和高剂量的细胞死亡作用，重楼皂苷Ⅶ会引发Beclin1裂解为Beclin1-c从而抑制重楼皂苷Ⅱ引起的自噬，达到二者联用增敏的作用。此外，RPS的17位羟基影响重楼皂苷对MMPs的选择，这些为继续开展RPS的药效物质与靶蛋白的效能关系提供依据。另外，课题组利用多种转移性肺癌模型（包括CT26结肠癌肝、肺转移模型，H22肝癌肺转移模型，二乙基亚硝胺诱发的肝癌肺转移模型等），H460人肺癌、HepG2人肝癌裸鼠模型等评价了RPS与索拉非尼、顺铂等联用的抗肿瘤活性。与索拉非尼联用，可抑制索拉非尼单独使用引发的线粒体损伤、厌氧糖酵解和脂代谢重编程等现象，发挥抑制肿瘤转移的作用。与顺铂联合，可诱发P53依赖性的DNA损伤，且能降低DNA损伤修复的产生，显著提高肺癌细胞凋亡率，同时，重楼皂苷II可抑制肿瘤的脂质代谢重编程，最终增敏顺铂。以上结果为RPS在抗肿瘤中的临床应用提供理论依据，同时为以RPS为核心的中成药新药研发提供临床前数据支持。