一种新齐墩果酸衍生物银莲花素A靶向ABC蛋白逆转骨肉瘤化疗耐药作用机制研究

骨肉瘤化疗耐药是当今亟待于解决的难题。 ABC家族蛋白的异常高表达，在耐药机制中扮演重要角色。从天然物筛选新的抗肿瘤化合物具有广阔前景，银莲花素A（RA）是齐墩果烷为母核的三萜皂苷类化合物，具有抑制血管生成、细胞增殖和诱导凋亡等作用。本项目前期工作表明，RA对尤其是耐药骨肉瘤细胞具有良好的杀伤作用，在体内抑制骨肉瘤的生长，且RA可抑制ABCB1、ABCC1和ABCG2的表达，激活JNK通路。因此我们提出假说，RA靶向ABC家族蛋白逆转骨肉瘤耐药，其机制为Erk/JNK/c-Jun信号通路激活，活化转录调控因子c-Jun（AP-1），结合ABC家族启动子，抑制ABC蛋白表达，从而逆转耐药。本项目拟使用CRISPR CAS9和其他多种实验技术，阐明RA靶向ABC家族逆转骨肉瘤化疗耐药的分子机制，为解决临床化疗耐药难题提供扎实的理论基础。

Osteosarcoma chemotherapy multidrug resistance（MDR） is the urgent need to solved problem. Upregulation the ATP-binding cassette（ABC）family, including ABCC1, ABCB1 and ABCG2 abnormally, is one of the major cause to multidrug resistance in cancer, which eventually leads to the failure of cancer chemotherapy. Raddeanin A (RA), is a cytotoxic oleanane-type triterpenoid saponin, a traditional Chinese medicinal herb, which suppresses the angiogenesis, inhibits the cell proliferation and induces cell apoptosis, and so on. Our previous work has demonstrated that RA can significantly decrease the viability of osteosarcoma cells in vitro and in vivo，and decrease the viability of multidrug resistance osteosarcoma cells especially. The precious work suggestted that RA reverses multidrug resistance by targeting ABC family in osteosarcoma. Therefore we proposed that RA target ABC family to active the Erk/Jnk/c-Jun signaling pathways, and activation of the transcription regulatory factors c-Jun (AP-1) ,which combinated on the promoter region of the ABC family, inhibits the protein expression of ABC family.We will use the CRISPR CAS9 gene edit and varies of other experimental technique, to investigate the molecular mechanism of reversing multidrug resistance by targeting the ABC family in human osteosarcoma. The application of RA to restore sensitivity of osteosarcoma MDR cells to the cytotoxic effects of chemotherapeutics will be useful for further study of MDR in human cancer and may ultimately benefit cancer patients.