水通道蛋白3在上皮间质转化介导的胃癌侵袭转移中的作用及机制

Invasion and metastasis are the most important prognostic factors for gastric carcinoma, and epithelial mesenchymal transition (EMT) and acquired stem cell-like properties of tumor cells are involved in the invasion and metastasis of gastric carcinoma. Our previous studies showed that the gastric cancer tissue presents over-expression of aquaporin 3 (AQP3), which is associated with lymph node metastasis. In addition, AQP3 over-expression can promote invasion and metastasis of gastric cancer, but the molecular mechanism remains unclear. We have recently found that AQP3 can upregulate MMP-2 and MMP-9 expression, downregulate E-Cadherin expression and increase CD44 expression in gastric carcinoma in vitro. Therefore, we hypothesize that: AQP3 can promote invasion and metastasis of gastric cancer via inducing EMT occurrence and acquired stem cell properties. The project includes: (1) clinical study with the specimens of gastric carcinoma to confirm the regulation of AQP3 on EMT in gastric cancer, (2) in vitro study to investigate the mechanisms of AQP3 on regulating EMT and acquired stem cell properties in gastric cancer, and (3) in vivo study to further validate the role of AQP3 on regulating EMT and acquired stem cell properties, and to explore the experimental therapeutic effect of the blockage of AQP3 on invasion and metastasis in the xenograft model and in the induced gastric cancer model. This study will help to elucidate the role and mechanism of AQP3 on the invasion and metastasis of gastric cancer, and provide experimental evidence for AQP3 as the potential therapeutic target for the invasion and metastasis of gastric cancer.

侵袭转移严重影响胃癌患者预后，上皮间质转化（EMT）和干细胞特性获得与胃癌侵袭转移密切相关。我们前期研究显示胃癌组织水通道蛋白3（AQP3）表达上调，AQP3可促进胃癌侵袭转移，但其机制尚不清楚。我们最近发现AQP3可使胃癌细胞MMP-2及MMP-9表达上调、E-Cadherin表达下调、CD44表达增加。因此，我们推测：AQP3通过促进胃癌EMT发生，使胃癌细胞获得干细胞特性，促进胃癌侵袭转移。本项目内容包括：（1）临床标本研究明确AQP3调节胃癌EMT；（2）体外研究AQP3调节EMT、干细胞特性获得的机制；（3）移植瘤及诱发瘤模型进一步验证AQP3调节EMT、干细胞特性获得的作用与机制，并探讨阻断AQP3对胃癌转移的实验性治疗作用。本研究有助于阐明AQP3在胃癌侵袭转移中的作用与机制，为将AQP3作为胃癌侵袭转移防治靶点提供实验依据。

肿瘤细胞上皮间质转化（epithelial-mesenchymal transition，EMT）及干细胞特性获得是胃癌侵袭转移的关键因素。我们前期研究显示胃癌组织水通道蛋白3（aquaporin3，AQP3）表达上调，AQP3可促进胃癌侵袭转移，但其机制不清。在本项目资助下，我们进行了较为系统的研究。（1）胃癌组织AQP3表达明显高于相应正常黏膜；在胃癌组织表达EMT相关蛋白；AQP3与EMT相关蛋白表达具有相关性且与患者生存期呈负相关；AQP3调控胃癌细胞增殖、迁移与侵袭；AQP3通过PI3K/AKT/SNAIL信号通路介导胃癌细胞EMT的发生。（2）胃癌组织CD44表达增加，且与AQP3表达具相关性；AQP3及CD44表达均与胃癌Lauren分型、淋巴结转移及脉管浸润显著相关；AQP3表达上调或下调后，胃癌细胞CD44表达、平板克隆形成能力、锚定非依赖性生长能力及胃癌细胞球形成能力则相应增减；AQP3通过Wnt/GSK -3β/β-catenin通路调控CD44表达。（3）胃黏膜肠上皮化生（gastric intestinal metaplasia，GIM）是胃癌前状态，我们发现AQP3在杯状细胞膜上特异性表达，采用gastric mucosal sausage roll技术对胃窦小弯侧肠型胃癌进一步研究提示AQP3可能在GIM癌变过程中发挥重要作用；AQP3与CD24有望成为GIM的分子标志，为胃黏膜GIM筛查提供精准策略。（4）胃黏膜癌变过程中如何获得AQP3表达？临床病理研究显示胃癌AQP3表达与H. pylori感染呈正相关；H. pylori感染可通过ROS/HIF-1α上调AQP3表达，并形成ROS/HIF-1α/AQP3/ROS环路；小鼠H. pylori感染模型证实了细胞学发现。.我们还开展了其他研究，结果显示：高血糖可通过AQP3促进胃癌进展；AQP3可通过促进自噬导致胃癌细胞对顺铂耐药；成功构建了人胃癌斑马鱼卵patient-derived xenograft（PDX）模型，为开展进一步研究奠定了基础。.本项目阐明了AQP3通过促进胃癌细胞EMT及干细胞干性获得进而促进胃癌侵袭转移的作用及机制，明确AQP3在胃黏膜炎癌转化及胃癌发生、发展中的作用，为将AQP3作为胃癌预防与治疗的靶点提供理论依据与实验基础。