外泌体蛋白PPP1CB介导的食管癌放疗抵抗机制研究

局部晚期食管癌患者放化疗抵抗仍然是临床治疗所面临的一个挑战，迫切需要一种无创的液体标志物在治疗前精确地预测食管癌患者对放化疗是否敏感。研究表明放疗可以促进肿瘤细胞外泌体释放，至于外泌体蛋白通过何种机制介导食管癌放疗抵抗尚不清楚。我们前期以食管癌耐放射细胞为模型，建立和优化外泌体分离、纯化及检测平台；利用蛋白质谱iTRAQ/TMT方法确定差异表达的外泌体蛋白；本课题以外泌体蛋白PPP1CB为研究对象，探讨PPP1CB的生物学功能；筛选PPP1CB相互作用蛋白(PIPs)，确定PPP1CB-PIPs作用模式；检测血清PPP1CB蛋白水平，确定其与食管癌放疗疗效及预后的关系；应用外泌体递送系统(PPP1CB siRNA-iExosome 或PPP1CB调节蛋白-Exosome)，确定其是否影响使放疗敏感性；深入阐述外泌体蛋白PPP1CB介导的食管癌放疗抵抗机制，为临床个体化精准治疗提供依据。

Radiochemoresistance of patients with locally advanced esophageal cancer （ESCC）is still a challenge for the clinical treatment. A noninvasive liquid biomarker is urgently needed to accurately predict the sensitivity of patients with ESCC before treatment. Previous studies showed that radiotherapy can promote the release of exosomes in cancer cells. However, the mechanism of exosomal protein mediating radioresistance of esophageal cancer remains unclear. We used the radioresistant esophageal cancer cell model, and established methods of exosome isolation and purification. Protein spectrum（ITRAQ/TMT）is used to determine the type of exosome-derived proteins, and identify the differentially expressed exosomal proteins. In this study, we explore the biological function of PPP1CB. PPP1CB interaction proteins (PIPs) will be screened using protein spectrum and determine the model of PPP1CB-PIPs interaction. Moreover, serum PPP1CB will be detected in patients with ESCC using EILSA kit，and identify the correlation of PPP1CB protein levels with the pathological response or prognosis. The exosome-based delivery systems (PPP1CB siRNA-iExosome or PPP1CB regulated protein-exosome) will be used to explore whether or not PPP1CB affect the sensitivity of radiotherapy. This study, focusing on the role of PPP1CB in regulating radiosensitivity in ESCC, could be a promising non-invasive biomarker for facilitating personalized treatments.