幽门螺杆菌（H. pylori）感染会导致异常的DNA甲基化并增加胃癌（GC）的风险。鸟苷酸结合蛋白亚基β-4（GNB4）参与各种肿瘤发生过程。我们在以前的生物信息学分析中发现在H. pylori诱导的GC中，GNB4的甲基化水平异常；然而，它的表达和基础分子机制知之甚少。我们对当地的107名GC患者和几个公共数据库进行了GNB4的表达、基础信号通路和临床意义的分析。H. pylori感染在体外和体内模型中诱导。使用甲基化特异性PCR、焦磷酸测序和质谱分析检测甲基化水平的变化。在GC细胞系中，过表达或敲低GNB4、TET1和YAP1。我们进行了增益和失去功能实验，包括CCK-8、EdU、菌落形成、Transwell迁移和侵袭实验。裸鼠被注射随机改变的GC细胞，测量异种移植肿瘤和转移的生长。进行实时定量PCR、Western blotting、免疫荧光、免疫组化、染色质免疫共沉淀和共免疫沉淀实验以阐明基础分子机制。GNB4表达在GC中显著上调，并与侵袭性临床特征和不良预后相关。增加的GNB4水平与较短的生存时间相关。H. pylori 26695和SS1菌株的感染诱导GC细胞和小鼠GNB4mRNA和蛋白表达。此外，静默GNB4阻止了H. pylori在GC细胞中的增殖、转移和侵袭能力。H. pylori感染显着降低了GNB4启动子区域的甲基化水平，尤其是在CpG #5位点（chr3:179451746-179451745）。 H. pylori感染通过激活NF-κB上调TET1表达。TET结合GNB4启动子区域，经过去甲基化修饰。在功能上，我们确定了GNB4通过Hippo-YAP1信号通路诱导肿瘤的致癌行为，无论在体内还是体外模型中。我们的发现表明，H. pylori感染激活了NF-κB-TET1-GNB4去甲基化-YAP1的轴，这可能是GC的潜在治疗靶点。©2023.作者（们）。

Helicobacter pylori (H. pylori) infection causes aberrant DNA methylation and contributes to the risk of gastric cancer (GC). Guanine nucleotide-binding protein subunit beta-4 (GNB4) is involved in various tumorigenic processes. We found an aberrant methylation level of GNB4 in H. pylori-induced GC in our previous bioinformatic analysis; however, its expression and underlying molecular mechanisms are poorly understood.The expression, underlying signaling pathways, and clinical significance of GNB4 were analyzed in a local cohort of 107 patients with GC and several public databases. H. pylori infection was induced in in vitro and in vivo models. Methylation-specific PCR, pyrosequencing, and mass spectrometry analysis were used to detect changes in methylation levels. GNB4, TET1, and YAP1 were overexpressed or knocked down in GC cell lines. We performed gain- and loss-of-function experiments, including CCK-8, EdU, colony formation, transwell migration, and invasion assays. Nude mice were injected with genetically manipulated GC cells, and the growth of xenograft tumors and metastases was measured. Real-time quantitative PCR, western blotting, immunofluorescence, immunohistochemistry, chromatin immunoprecipitation, and co-immunoprecipitation experiments were performed to elucidate the underlying molecular mechanisms.GNB4 expression was significantly upregulated in GC and correlated with aggressive clinical characteristics and poor prognosis. Increased levels of GNB4 were associated with shorter survival times. Infection with H. pylori strains 26695 and SS1 induced GNB4 mRNA and protein expression in GC cell lines and mice. Additionally, silencing of GNB4 blocked the pro-proliferative, metastatic, and invasive ability of H. pylori in GC cells. H. pylori infection remarkably decreased the methylation level of the GNB4 promoter region, particularly at the CpG#5 site (chr3:179451746-179451745). H. pylori infection upregulated TET1 expression via activation of the NF-κB. TET binds to the GNB4 promoter region which undergoes demethylation modification. Functionally, we identified that GNB4 induced oncogenic behaviors of tumors via the Hippo-YAP1 pathway in both in vitro and in vivo models.Our findings demonstrate that H. pylori infection activates the NF-κB-TET1-GNB4 demethylation-YAP1 axis, which may be a potential therapeutic target for GC.© 2023. The Author(s).