基于类器官技术探索胃癌腹水患者的腹腔液态微环境促进腹腔胃癌细胞恶性生物学行为的机制及其临床转化应用研究

胃癌腹膜转移及其合并的恶性腹水是胃癌患者的主要致死原因之一，但机制尚不明了，临床治疗效果亟需提高。胃癌高度异质性及缺乏有效的研究模型，制约了其基础研究进展。课题组前期成功构建了胃癌恶性腹水肿瘤类器官（MADO），并在病理组织学、基因组学和分子标志物等多个层面证实了MADO保持了亲本来源腹水癌细胞的异质性，药敏反应发现MADO对不同药物敏感性不同，提示其具有个体化筛药的潜在应用价值。研究中发现，恶性腹水是MADO存活和增殖所必须的，且恶性腹水胃癌细胞产生大量与T细胞增殖、活化和分化相关的基因突变，提示恶性腹水中可能存在影响腹水中肿瘤细胞增殖等恶性生物学行为的特殊“液态微环境”。本项目拟利用临床样本、动物模型、MADO模型和分子技术探讨胃癌恶性腹水与腹水胃癌细胞crosstalk的作用机制，并揭示恶性腹水分子分型和MADO作为药物筛选和指导临床用药的潜能，为胃癌腹膜转移精准治疗。

Malignant ascites (MA) is a common manifestation in advanced gastric cancer withperitoneal carcinoma and usually indicates a poor prognosis. However, lack of in vitro models that can faithfully recapitulate the characteristics of tumour cells in ascites hinders related researches. Tumour organoids have emerged as a robust in vitro model for tumour research and drug screening. Yet, the potential of using the malignant ascites-derived organoids(MADOs) for disease modelling and drug screening remains an open question. In our study, we successfully generated 11 MADOs from MA tumour cells of gastric cancer patients. Our results demonstrated MA was essential for the survival and proliferation of MADO, whereas the growth ratio of MADOs, which were incubated with MA with same concentration from different patients, were different. And using immunohistochemistry (IHC) and genomics by whole-exome sequencing (WES), we conpared MADOs with original MA tumour cells in histology and genomics respectively. The results suggested that MADO cultures preserve the histological architecture, genomic landscape of the corresponding MA tumour cells. Notably, we also found that abundant mutations existed, which were associated with the proliferation, activation and differentiation of T cells. In additionally, we tested whether MADOs could be used for drug sensitivity screens and we found that MADOs exhibited heterogeneous responses to standard-of-care chemotherapeutics. Herein, in this project, we will reveal the crosstalk between MA and gastric cancer cells in MA, which may provide basis for clinical therapy for advanced gastric cancer with peritoneal carcinama.