胃癌外泌体中SERPINA3通过HNRNPA1/Rubicon轴调控巨噬细胞LC3相关吞噬促进化疗后免疫耐受的机制研究

“冷肿瘤”类型胃癌在化疗后可出现肿瘤免疫微环境中巨噬细胞浸润及T细胞缺乏，导致免疫耐受继而发生化疗抵抗。我们在前期研究发现胃癌外泌体中SERPINA3蛋白促进巨噬细胞对化疗诱导凋亡细胞LC3相关吞噬作用，并抑制巨噬细胞固有免疫反应及活化。根据预实验结果，我们提出“胃癌外泌体中SERPINA3被巨噬细胞摄取后与HNRNPA1结合，发生核转位并激活Rubicon转录，调控LC3相关吞噬进而促进胃癌化疗后免疫耐受”的机制假说。本项目拟利用多种体内外模型明确SERPINA3调控巨噬细胞LC3相关吞噬并抑制其活化的生物学功能；并结合生信分析、分子生物学技术、高通量测序及Rubicon敲除小鼠模型等深入探讨SERPINA3调控巨噬细胞LC3相关吞噬的具体分子机制。本项目的顺利完成有助于完善对SERPINA3在胃癌化疗后免疫耐受中的功能及机制认识，并有望为胃癌化疗抵抗提供新的免疫微环境靶点。

Abundant infiltration of macrophages and low infiltration of T cells in tumor immune microenvironment were characterized in “cold tumor” type gastric cancer after chemotherapy, which promoted immune tolerance and ultimately chemotherapy resistance. Our preliminary data showed that exosomal SERPINA3 protein from gastric cancer cells promoted LC3-associated phagocytosis(LAP) of chemotherapy-induced apoptotic cells in macrophages, thus inhibited innate immunity and activation. According to preliminary results, we hypothesized that exosomal SERPINA3 protein from gastric cancer cells was intaked by macrophages and modulated HNRNPA1’s transcriptional activity on Rubicon via its interaction with HNRNPA1 and promotion of nuclear translocation. Upregulation of Rubicon contributed to LAP in macrophages and induced immune tolerance after chemotherapy. To test the hypothesis, this program will identify the biological function of SERPINA3 in modulating LAP and activation of macrophages both in vitro and in vivo, and further explore the detailed mechanism with bioinformatic analysis, molecular biological techniques, high-throughput sequence and Rubicon-knockout mice. This study will provide new insights into the function of SERPINA3 in immune tolerance of gastric cancer after chemotherapy, and identify a new therapeutic target in immune microenvironment for the treatment of chemotherapy-resistant gastric cancer.