基于Hsp90蛋白靶标的雷公藤红素抑制乳腺癌作用机制研究

Breast cancer is one of the malignant tumors that threaten women's health in the world. Currently, clinical treatment of breast cancer is facing a serious challenge. In recent years, traditional chinese medicine (TCM) has received increasing attention to the treatment of tumors, and there have been more studies and effective clinical applications. Celastrol is one of the effective components of Tripterygium wilfordii, which is a natural product with various biological activities. Studies have shown that celastrol has the potential capacity to treat breast cancer, but its mechanism and direct target proteins are still unclear. Our previous study showed that celastrol could inhibit the growth of breast cancer cells and tumor in mice. Furthermore, celastrol could directly interact with intracellular Hsp90 protein, suggesting that Hsp90 protein and its downstream service protein may be involved in inhibiting the growth of breast cancer cells. In view of this, we intend to explore the direct target protein of Tripterygium wilfordii by using activity-based proteomics method, and to explore the signal pathways and important cellular processes affected by celastrol. The structural basis and molecular mechanism of its effect on Hsp90 and its service protein were elucidated by structural biology and molecular biology methods, which provided the structural basis and new targets for celastrol as a potential antineoplastic drug.

乳腺癌是世界范围内威胁女性健康的恶性肿瘤之一，目前临床治疗乳腺癌面临严峻挑战。近些年，中医药在肿瘤的治疗中日益得到人们的关注和重视，已有较多的研究及有效的临床应用。雷公藤红素是中药雷公藤的有效成分之一，是一种具有多种生物活性的天然产物。研究表明雷公藤红素表现出潜在治疗乳腺癌的能力，然而其作用机理及直接靶标蛋白目前尚不清楚。申请人前期发现雷公藤红素可明显抑制乳腺癌细胞及小鼠肿瘤的生长，进一步实验发现雷公藤红素可直接与细胞内Hsp90蛋白相互作用，提示Hsp90蛋白及其下游服务蛋白可能参与抑制乳腺癌细胞的生长。鉴于此，我们拟利用化学蛋白质组学方法探究雷公藤红素的直接靶标蛋白，探索其影响的信号通路及重要细胞过程，同时结合结构生物学和分子生物学方法阐明其影响Hsp90及其服务蛋白的结构基础和分子机理，为雷公藤红素作为潜在抗癌药提供新的靶标和结构基础。

雷公藤红素（celastrol，cel）是一种天然衍生的化合物，其药理作用被广泛研究，包括抗肿瘤、抗肥胖和抗炎。越来越多的证据表明，雷公藤红素对广泛的癌细胞，包括前列腺癌、肝癌、乳腺癌、黑色素瘤和胶质瘤表现出有效的抗肿瘤功效。尽管对雷公藤红素已经有了大量的研究，但其如何抑制乳腺癌仍不清楚。.本课题采用定量化学蛋白质组学方法，对雷公藤红素结合的蛋白靶点进行了全面分析，总共有800个蛋白靶点被确定为雷公藤红素的靶标。分析发现有100多个蛋白靶点可信度较高。有研究发现HDSL2蛋白与乳腺癌相关，HSDL2也是最可靠的靶点之一。我们利用CETSA技术和靶点垂钓技术证明了雷公藤红素可直接与HSDL2蛋白结合。细胞成像实验证实，cel-p可以进入细胞，与HSDL2共定位，并与雷公藤红素竞争。原位细胞给药后，随着雷公藤红素药物浓度的增加，HSDL2的表达可受到抑制，促凋亡蛋白BaX的表达增加，抗凋亡蛋白BcL2的表达降低，从而诱导细胞凋亡。si-HSDL2转染细胞后，细胞凋亡增加，过表达后凋亡相反，提示雷公藤红素可能通过抑制HSDL2的表达来促进乳腺癌细胞凋亡，进而发挥抗乳腺癌的作用，我们的研究结果为雷公藤红素作为潜在抗癌药提供新的靶标和研究基础。