胃癌细胞源性外泌体蛋白Hsp90ab1通过激活血管内皮细胞促进胃癌转移的机制研究

Infiltration and metastasis are the important factors which affected the prognosis of patients with gastric cancer. Its mechanism is complex and it is still a hot topic of current research. We previously found that Hsp90ab1 protein expression was detected in gastric cancer cell-derived exosomes, and exosomes could increase vascular permeability and promote vascular endothelial cell infiltration and migration. Silencing Hsp90ab1 can inhibit the content of inflammation-related protein S100A9 in exosomes, and thus proposes the research hypothesis that "gastric cancer cell - derived exosomal protein Hsp90ab1 promotes gastric cancer metastasis by activating vascular endothelial cells", this project intends to detect the expression of Hsp90ab1 and its related proteins in clinical samples and analyze its clinical significance on the basis of the preliminary study by using elisa. To clarify the effect of Hsp90ab1 on the biological behavior of cells in vitro and in vivo, we identify and analyze the downstream proteins interacting with Hsp90ab1 by mass spectrometry, identify and determine the ligands between exocytic activated vascular endothelial cells, and the biological function of Hsp90ab1 in exosomes in gastric cancer metastasis was clarified, and the molecular mechanism of Hsp90ab1 affecting S100A9 content and activating vascular endothelial cells was clarified, and then we provide new ideas for the occurrence, development and related mechanisms of gastric cancer.

浸润和转移是影响胃癌患者预后的重要因素，其机制复杂多样，仍是目前研究热点。我们前期在胃癌细胞源性的外泌体中检测到Hsp90ab1表达，且外泌体可增加血管通透性，促进血管内皮细胞浸润和迁移；沉默Hsp90ab1能抑制外泌体中炎症相关蛋白S100A9的含量，由此提出“胃癌细胞源性外泌体蛋白Hsp90ab1通过激活血管内皮细胞促进胃癌转移的机制研究”的研究假设，本项目拟在前期基础上，利用酶联免疫吸附检测临床样本中Hsp90ab1及其相关蛋白的表达并分析其临床意义；从体内外明确外泌体中Hsp90ab1对细胞生物学行为的影响，通过质谱分析鉴定与并分析与Hsp90ab1相互作用的下游蛋白，鉴别并确定外泌体激活血管内皮细胞间的配体，明确外泌体中Hsp90ab1在胃癌转移中的生物学功能并阐明Hsp90ab1影响S100A9含量并激活血管内皮细胞的分子机制，为胃癌的发生、发展及其相关的机制提供新思路。

浸润和转移是影响胃癌患者预后的重要因素，而血管生成在胃癌浸润和转移中扮演着重要角色，因此更好地阐明肿瘤血管生成的机制具有重要而深远的意义。迄今为止，研究人员对外泌体中Hsp90ab1的表达对肿瘤血管生成的影响知之甚少。在本研究中我们探究了外泌体中Hsp90ab1对胃癌血管生成的影响并初步阐明了其机制。首先我们统计了临床血清样本中Hsp90ab1及S100A9蛋白的表达情况，发现Hsp90ab1、S100A9的表达与肿瘤病人预后息息相关；体内外实验中，我们在胃癌细胞中通过过表达/沉默实验发现抑制Hsp90ab1表达后外泌体中Hsp90ab1蛋白影响血管内皮细胞的生成且EMT通路受到影响；后续分子实验中，我们研究发现S100A9是Hsp90ab1的下游靶蛋白，二者存在相互作用且该相互作用可靶向调节 S100A9 蛋白的稳定性；回复实验表明沉默S100A9表达能减弱Hsp90ab1对胃癌血管内皮细胞的影响，由此阐明外泌体中Hsp90ab1与S100A9 蛋白结合并靶向调节 S100A9 蛋白的稳定性增加外泌体中 S100A9蛋白进而促进胃癌血管生成参与胃癌演进过程。本研究以外泌体中Hsp90ab1为出发点阐明了其影响胃癌血管内皮细胞产生的可能机制，Hsp90ab1蛋白有望成为预防和治疗胃癌的一个潜在的药物作用靶标。