Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China; Department of Surgery, University of Miami Miller School of Medicine, Miami, Florida; Department of Thoracic Surgery, Jiangsu Cancer Hospital, Jiangsu Institute of Cancer Research, the Affiliated Cancer Hospital of Nanjing Medical University, Nanjing, Jiangsu, China.
Department of Surgery, University of Miami Miller School of Medicine, Miami, Florida.
Gastroenterology. 2022 Sep;163(3):620-636.e9. doi: 10.1053/j.gastro.2022.05.016. Epub 2022 May 17.
BACKGROUND & AIMS: Helicobacter pylori (H pylori) infection is the main risk factor for gastric cancer. The role of fibroblast growth factor receptors (FGRFs) in H pylori-mediated gastric tumorigenesis remains largely unknown. This study investigated the molecular and mechanistic links between H pylori, inflammation, and FGFR4 in gastric cancer.
Cell lines, human and mouse gastric tissue samples, and gastric organoids models were implemented. Infection with H pylori was performed using in vitro and in vivo models. Western blot, real-time quantitative reverse-transcription polymerase chain reaction, flow cytometry, immunofluorescence, immunohistochemistry, chromatin immunoprecipitation, and luciferase reporter assays were used for molecular, mechanistic, and functional studies.
Analysis of FGFR family members using The Cancer Genome Atlas data, followed by validation, indicated that FGFR4 messenger (m)RNA was the most significantly overexpressed member in human gastric cancer tissue samples (P < .001). We also detected high levels of Fgfr4 mRNA and protein in gastric dysplasia and adenocarcinoma lesions in mouse models. Infection with J166, 7.13, and PMSS1 cytotoxin-associated gene A (CagA)+ H pylori strains induced FGFR4 mRNA and protein expression in in vitro and in vivo models. This was associated with a concordant activation of signal transducer and activator of transcription 3 (STAT3). Analysis of the FGFR4 promoter suggested several putative binding sites for STAT3. Using chromatin immunoprecipitation assay and an FGFR-promoter luciferase reporter containing putative STAT3 binding sites and their mutants, we confirmed a direct functional binding of STAT3 on the FGFR4 promoter. Mechanistically, we also discovered a feedforward activation loop between FGFR4 and STAT3 where the fibroblast growth factor 19–FGFR4 axis played an essential role in activating STAT3 in a SRC proto-oncogene non-receptor tyrosine kinase dependent manner. Functionally, we found that FGFR4 protected against H pylori-induced DNA damage and cell death.
Our findings demonstrated a link between infection, inflammation, and FGFR4 activation, where a feedforward activation loop between FGFR4 and STAT3 is established via SRC proto-oncogene non-receptor tyrosine kinase in response to H pylori infection. Given the relevance of FGFR4 to the etiology and biology of gastric cancer, we propose FGFR4 as a druggable molecular vulnerability that can be tested in patients with gastric cancer.
幽门螺杆菌（H pylori）感染是胃癌的主要危险因素。成纤维细胞生长因子受体（FGRFs）在 H pylori 介导的胃癌发生中的作用在很大程度上尚不清楚。本研究旨在探讨 H pylori、炎症与 FGFR4 之间在胃癌发生中的分子和机制联系。
使用细胞系、人和鼠胃组织样本以及胃类器官模型进行研究。采用体外和体内模型进行 H pylori 感染。使用 Western blot、实时定量逆转录聚合酶链反应、流式细胞术、免疫荧光、免疫组织化学、染色质免疫沉淀和荧光素酶报告基因检测进行分子、机制和功能研究。
利用癌症基因组图谱（The Cancer Genome Atlas）数据对成纤维细胞生长因子家族成员进行分析，并进行验证，结果表明 FGFR4 信使（m）RNA 在人胃癌组织样本中表达最为显著（P <.001）。我们还在小鼠模型的胃发育不良和腺癌病变中检测到 Fgfr4 mRNA 和蛋白的高水平表达。在体外和体内模型中，J166、7.13 和 PMSS1 细胞毒素相关基因 A（CagA）+ H pylori 菌株的感染诱导了 FGFR4 mRNA 和蛋白的表达。这与信号转导和转录激活因子 3（STAT3）的一致性激活相关。FGFR4 启动子分析表明，STAT3 可能有几个结合位点。通过染色质免疫沉淀分析和含有 STAT3 结合位点及其突变的 FGFR 启动子荧光素酶报告基因检测，我们证实了 STAT3 直接在 FGFR4 启动子上的功能结合。在机制上，我们还发现了 FGFR4 和 STAT3 之间的正反馈激活环，其中成纤维细胞生长因子 19-FGFR4 轴通过 SRC 原癌基因非受体酪氨酸激酶以依赖方式在激活 STAT3 中发挥重要作用。功能上，我们发现 FGFR4 可防止 H pylori 诱导的 DNA 损伤和细胞死亡。
我们的研究结果表明，感染、炎症和 FGFR4 激活之间存在联系，在 H pylori 感染时，通过 SRC 原癌基因非受体酪氨酸激酶建立了 FGFR4 和 STAT3 之间的正反馈激活环。鉴于 FGFR4 与胃癌的病因和生物学有关，我们提出 FGFR4 是一种可测试的分子脆弱性，可在胃癌患者中进行测试。
