肿瘤源性白介素-11上调间质纤维连接蛋白促进胃癌生长的分子机制研究

Gastric cancer is one of the most malignant cancers in China, with high incidence and mortality rate. The interaction between tumor cells and tumor microenvironment plays important role in regulating tumor growth. In our pervious works, interleukin-11 (IL-11) was identified as an important effector on promoting growth of gastric cancer cells. However, the impact of tumor cell derived IL-11 on tumor microenvironment during growth of gastric cancer is currently unclear. In our preliminary work, expression of IL-11 was found positively correlated with expression of stromal fibronectin (FN) in gastric cancer tissues. Co-expression of IL-11 and FN was significantly correlated with advanced TNM stage. FN is one of the components of extracellular matrix, and mainly secreted by fibroblast, which can promote tumor growth. In tissue fibrosis, IL-11 participated in regulating stromal FN expression. Therefore, we hypothesize that inducing fibronectin expression in tumor stroma is one of the mechanisms of tumor cell derived IL-11 promoting gastric cancer growth. To validate the hypothesis, the main components of present study include: 1) To clarify the effect of gastric cancer cell derived IL-11 on FN expression of fibroblast and its mechanisms; 2) To investigate the impact of up-regulated FN of fibroblast on growth of gastric cancer cells regulating by IL-11.

胃癌是高度恶性肿瘤，发病率高、预后差。肿瘤细胞与其微环境相互调控是影响胃癌生长的重要因素。申请人既往研究报道，肿瘤源性白介素-11（Interleukin-11，IL-11）是促胃癌生长效应分子。然而，调控肿瘤微环境在IL-11促胃癌生长中的作用尚不明确。申请人前期工作显示，胃癌中IL-11与间质纤维连接蛋白（Fibronectin，FN）表达呈正相关，两者共表达与胃癌恶性表型相关。FN是肿瘤间质主要成分，源于成纤维细胞，参与肿瘤生长调控。纤维化疾病中，IL-11可调控FN表达。故课题假设，肿瘤源性IL-11可通过上调间质成纤维细胞FN表达促进胃癌生长。课题将从以下方面验证假设：1）明确胃癌细胞源性IL-11调控成纤维细胞FN表达的作用及分子机制；2）明确成纤维细胞FN表达上调在IL-11促胃癌细胞生长中的作用。上述研究将进一步阐明IL-11调控胃癌恶性表型的作用及分子机制。

IL-11作为分泌性细胞因子可能通过调控宿主微环境参与胃癌生长及转移调控。通过蛋白质组学分析显示，IL-11可影响间皮细胞内多种蛋白表达，并参与调控其生物学功能。IL-11可能通过激活下游RELA蛋白磷酸化上调TMOD1表达调控间皮细胞运动及细胞结构。通过收集患者外周血外泌体，应用蛋白质谱分析技术检测并比较外泌体中差异蛋白，鉴定发现与胃癌腹膜特异性转移潜在相关的外泌体蛋白质，并显示该差异蛋白功能与肌动蛋白细胞骨架功能、NF-κB信号通路及糖酵解/糖异生通路有关。而在发生肝脏特异性转移胃癌中，差异蛋白功能与脂肪消化和吸收、维生素消化和吸收及PPAR信号通路。腹膜转移患者外泌体中存在ACTG、VINC、ENOA、KPYM、CD14等蛋白的异常表达。肿瘤微环境异常除与肿瘤发生、发展、转移相关外，可参与调控肿瘤免疫微环境，进而影响免疫检查点抑制剂疗效。基于单细胞测序技术，比较接受免疫检查点抑制剂治疗后晚期胃癌患者多部位肿瘤样本中免疫细胞构成情况，发现特定亚群M2型巨噬细胞在治疗后出现富集。差异基因功能分析显示，该M2型巨噬细胞亚群下调基因功能富集与抗原提呈有关，而上调基因功能与中性粒细胞活化有关。同时，该亚群上调基因TIMP1、IFI27等具有促肿瘤作用，可能与治疗后肿瘤持续进展有关。通过全基因组检测发现，在HER2阳性胃癌中发现CDK12基因扩增，通过免疫组化检查显示，CDK12表达与胃癌患者恶性临床表型及不良预后有关，并可能通过调控CCL21表达，诱导CD8+细胞向肿瘤内浸润，进而参与调控肿瘤免疫微环境。上述研究围绕肿瘤与宿主微环境调控作用，探索胃癌腹膜特异性转移调控机制，以及影响胃癌免疫治疗疗效的重要因素及潜在分子机制。为临床诊疗策略优化及研发新治疗策略提供线索。