土木香中与顺铂相互作用增加卵巢癌耐药细胞敏感性的不饱和内酯类成分及调控信号通路研究

Cisplatin-resistance is a major hurdle in cancer chemotherapy. There is an urgent need to find an effective approach to overcome tumor resistance. We have recently found that the unsaturated lactones from Inula helenium may overcome the resistance of ovarian cancer cells to cisplatin at the low dose, at which the unsaturated lactone alone did not cause cell growth inhibition. Our previous study showed that the combinations of cisplatin with the unsaturated lactones such as alantolactone regulated the levels of phosphorylated Akt, phosphorylated p38 and NF-κB expression. Based on these findings, we will isolate a large number of the unsaturated-lactones from Inula helenium, test the potential of these compounds to sensitize cisplatin-resistant human ovarian cancer cells to cisplatin-induced cell death, and investigate the underlying mechanism. To reveal the critical signaling molecules regulated by the combinations of cisplatin and active compounds and elucidate the mechanism of synergetic effect, the cell microenvironment such as redox status and multiple signaling pathways including PI3K/Akt, MAPK and apoptosis pathway will be investigated. Furthermore, we will determine the synergetic effect on the inhibition of tumor xenograft growth and the changes of critical signaling molecules in vivo. This study will elucidate mechanism of synergetic effect on cisplatin-resistant ovarian cancer treated by the combinations of cisplatin with the unsaturated lactones. Successful completion of the proposed study will provide a novel strategy for developing new drug with a low toxicity to overcome tumor resistance to cisplatin.

肿瘤对顺铂耐药是临床化疗亟待解决的难题。申请者发现土木香中不饱和内酯类成分，在对细胞生长没有影响的剂量下，能逆转卵巢癌对顺铂的耐药作用；与顺铂合用可调控卵巢癌耐药细胞Akt、p38磷酸化水平及NF-kB等的表达。基于这类成分新的活性及解决肿瘤对顺铂耐药的迫切需求，本项目拟采用现代色谱分离技术，从土木香中获得多种具有逆转卵巢癌对顺铂耐药作用的不饱和内酯类成分，研究该类成分调控耐药细胞环境以及与顺铂的相互作用、调控PI3K/Akt及MAPK信号通路与细胞凋亡的关系，探讨不饱和内酯类化合物增加耐药细胞对顺铂敏感性的分子机制，揭示该类化合物如何与顺铂相互作用和调控的关键信号分子，并采用裸鼠模型确证该类化合物逆转卵巢癌对顺铂的耐药作用和涉及的主要信号通路。该研究为克服卵巢癌耐药提供重要的理论和实验依据，为寻找高效低毒的肿瘤顺铂耐药逆转剂开辟新途径。

卵巢癌患者死亡率高，顺铂作为卵巢癌治疗一线药物，绝大多数病人治疗初期对顺铂很敏感，但最终出现耐药性，导致病情难以控制而死亡。因此，寻找顺铂增敏剂，克服肿瘤耐药具有重要意义。该项目从土木香中提取分离倍半萜及其衍生物，获得主要类型为不饱和内酯类成分，包括一系列新化合物，其中6个为新骨架类型化合物,评价获得化合物增加顺铂对卵巢癌耐药细胞敏感性的药效，进行构效分析。对主要活性化合物进行作用机制研究，包括对耐药细胞DNA损伤、氧化还原状态、凋亡及自噬的相关蛋白、PI3K/Akt及MAPK通路的调控，并进行裸鼠体内药效试验及调控关键信号分子的研究。该项目揭示了土木香中倍半萜类成分克服顺铂耐药的构效关系，发现活性化合物与顺铂相互作用促进ROS产生，抑制自噬促进细胞凋亡，揭示了调控耐药细胞中mcl-1、PI3K/Akt等信号通路和自噬及凋亡的关系，阐释了活性化合物逆转卵巢癌顺铂耐药机制，为克服肿瘤耐药提供了重要的理论依据，同时为发现逆转肿瘤耐药的先导化合物开辟了新方向。该项目也丰富了土木香中化学成分类型，对该植物资源充分利用具有重要意义。发表SCI论文10篇，其中新骨架类型化合物发表在Organic Letters及 Organic Chemistry Frontiers期刊。申报发明专利2项。