基于紫杉醇耐药特异性导向的两种胡椒属植物中二聚酰胺类生物碱及抗肿瘤耐药机制研究

肿瘤耐药机制极其复杂，克服肿瘤耐药是急需解决的难题。前期研究中，本项目组首次发现胡椒属植物荜茇和胡椒中的二聚酰胺类生物碱具有逆转紫杉醇耐药的活性。该类成分在没有细胞毒的剂量下，与紫杉醇合用调控宫颈癌紫杉醇耐药细胞中Mcl-1、p-Akt、HIF-1α等的表达，促进自噬死亡与凋亡。本项目拟在前期研究基础上，基于NMR特征信号及LC-MS/MS分析方法，采用现代色谱分离技术，从荜茇和胡椒植物中获得多种具有逆转紫杉醇耐药作用的二聚酰胺类生物碱；研究该类生物碱与紫杉醇联用对耐药细胞环境、自噬、凋亡及葡萄糖酵解的影响，采用基因干扰及过表达等手段，研究Noxa/Mcl-1轴的变化、PI3K-Akt-mTOR通路及HIF-1α之间的关系，揭示调控的关键信号枢纽，阐释该类成分克服紫杉醇耐药的分子机制，并采用裸鼠模型确证该类活性化合物作用效果和涉及的主要信号通路，为克服紫杉醇耐药开辟新方向。

Complex mechanisms have been implicated in cancer drug resistance, which is a major problem facing current cancer research, and there is an urgent need to find effective approaches to overcome drug resistance. We have recently found that the dimeric amide alkaloids from two plants of the genus Piper, including Piper longum and Piper nigrum, can overcome the resistance of cancer cells to paclitaxel. At a low dose, at which this dimeric amide alkaloid alone did not cause cytotoxic effect, the combination of this alkaloid with paclitaxel regulated the expression levels of Mcl-1, phosphorylated Akt and HIF-1α, caused autophagic cell death, and enhanced apoptosis. In order to search for more dimeric amide alkaloids which can overcome the resistance of cancer cells to paclitaxel, we will isolate these alkaloids from the Piper longum and Piper nigrum by modern chromatograph approaches, based on the characteristic NMR signals and LC-MS/MS characteristic spectrum analysis. To elucidate the molecular mechanisms of active dimeric amide alkaloids, the effects of the combination treatment of paclitaxel with these active compounds on the paclitaxel-resistant cell microenvironment, autophagy, apoptosis and glycolysis will be investigated. To reveal the critical signaling molecules regulated by the combination treatment, the interaction and correlations among Noxa/Mcl-1 axis, PI3K-Akt-mTOR pathway and HIF-1α will be explored through gene silencing and overexpressing. Furthermore, the inhibition effects on tumor xenograft growth and the changes of critical signaling molecules in vivo will be determined. Successful completion of the project will find novel approaches for developing new drug to overcome tumor resistance to paclitaxel.