抑瘤沙门氏菌在肿瘤原位的蛋白质表达组研究

As an emerging type of biological agent, the anti-tumor Salmonella is able to repress tumor growth and metastasis, has a great potential in targeted cancer therapy. Previously, we found that, Salmonella has different impacts on its host in vivo and in vitro . However, the absent methodology for translatome profiling of the Salmonella in tumor holds up the understanding of its anti-cancer mechanism. Therefore, "how to profile the bacterial translatome in mouse tumor with an ultra high sensitivity?" has become the key scientific question in this project. Its major bottleneck is that, in the tumor tissue, the bacterial protein concentration is several magnitude lower than the murine proteins, leading to a difficult identification of them from the mixture. We propose that, through developing a new chemical proteomics method combining unnatural amino acid incorporation and Click chemistry, we can efficiently and selectively enrich the bacterial proteins from the tumor tissue lysates, and subsequently identify and quantify them. With this method, we plan to compare the translatome profiling of anti-tumor salmonella under different growth conditions (in mouse tumor and in co-cultures) in a quantitative manner. This is an important methodological innovation to study the molecular pharmacology of medical synthetic microbial, and also an useful tool for the next generation design and modification of the bacteria.

作为一种新型抗癌生物制剂，抑瘤沙门氏菌对肿瘤生长和转移表现出显著的抑制效果，在肿瘤治疗方面具有广阔的应用前景。我们前期发现沙门氏菌在体内和体外环境中对宿主的影响不同。但是其在小鼠肿瘤原位的蛋白质表达组仍无法有效鉴定，这严重的阻碍了其抗癌分子机制研究的深入。因此，“如何对肿瘤原位的抑瘤沙门氏菌蛋白质表达组进行超高灵敏度鉴定？”成为本项目的关键科学问题。目前的主要瓶颈在于，细菌蛋白在肿瘤原位的浓度要远低于小鼠蛋白，常规蛋白质组学方法无法在高背景中有效鉴定细菌蛋白。申请人提出，利用非天然氨基酸嵌入结合Click化学的新型化学蛋白质组学方法，高效的实现抑瘤沙门氏菌的蛋白质富集，高灵敏度鉴定其蛋白质表达组。我们将应用该方法，对抑瘤沙门氏菌在肿瘤原位和体外共培养环境的基因线路表达谱进行定量表征。这对医学合成微生物的分子药理学研究是一种重要的方法创新，同时对于新型抑瘤细菌的设计和改造也有重要的指导意义。

抑瘤沙门氏菌对肿瘤生长和转移表现出显著的抑制效果，在肿瘤治疗方面具有广阔的应用前景。但沙门氏菌在小鼠肿瘤原位的蛋白质表达组仍无法有效鉴定，这严重的阻碍了其抗癌分子机制研究的深入。为了解析抑瘤沙门氏菌的抗癌机制，我们对沙门氏菌与宿主细胞互作蛋白质组进行时空动力学解析。研究团队综合利用多种新型化学和定量蛋白质组学方法，高效的实现（抑瘤）沙门氏菌及宿主细胞新生蛋白的有效富集，高灵敏度鉴定其蛋白质表达组。我们应用该方法，对（抑瘤）沙门氏菌治疗后肿瘤原位蛋白质表达组变化及宿主细胞新生蛋白质表达组变化进行解析，揭示了在沙门氏菌治疗后的肿瘤和宿主内的免疫学变化过程，沙门氏菌侵入宿主细胞后的蛋白质表达谱，及沙门氏菌诱导宿主细胞死亡的新机制。这对医学合成微生物的分子药理学研究是一种重要的方法创新，同时对于新型抑瘤细菌的设计和改造也有重要的指导意义。