背景:激活转录因子3(ATF3)在人膀胱中的功能仍未研究。这项研究深入研究了表达,功能,ATF3在人膀胱癌中的调控机制。
方法:用免疫印迹法测定基因表达,RT-qPCR,和报告分析。Ki67的测定,殖民地形成,基质胶入侵,异种移植动物研究用于评估细胞增殖,入侵,和体外和体内肿瘤发生。来自TCGA数据库的Silico分析检查了GDF15和ATF3表达之间的相关性,临床病理特征,和无进展生存率。
结果:Silico分析证实ATF3是一种抗肿瘤基因,膀胱癌组织中的表达与GDF15呈正相关。多因素分析显示,ATF3/GDF15低表达而不是ATF3低表达是膀胱癌患者无进展生存期的独立预后因素。ATF3的异位过表达下调膀胱癌细胞的体外增殖和侵袭,而ATF3敲低逆转了这些结果。敲除ATF3上调EMT标记以增强体外细胞侵袭和下调GDF15、NDRG1和KAI-1以提高体内肿瘤生长。二甲双胍对膀胱癌细胞ATF3和GDF15的激活被TGFβ受体抑制剂SB431542阻断。ATF3通过反馈回路正向调节膀胱癌细胞中的GDF15表达。
结论:我们的结果确定ATF3是二甲双胍上调的抗肿瘤基因。Silico分析的结果与基于细胞的研究一致,表明低ATF3/GDF15可能是膀胱癌的阴性预后标志物。
BACKGROUND: The functions of activating transcription factor 3 (ATF3) within the human bladder remain unexplored. This study delves into the expressions, functions, and regulatory mechanisms of ATF3 in human bladder cancer.
METHODS: Gene expressions were determined by immunoblot, RT-qPCR, and reporter assays. Assays of Ki67, colony formation, Matrigel invasion, and the xenograft animal study were used to assess the cell proliferation, invasion, and tumorigenesis in vitro and in vivo. Silico analysis from TCGA database examined the correlations between GDF15 and ATF3 expressions, clinicopathologic features, and progression-free survival rates.
RESULTS: Silico analysis confirmed that ATF3 is an antitumor gene, and the expression positively correlates with GDF15 in bladder cancer tissues. Multivariate analysis revealed that low ATF3/GDF15 but not a single low expression of ATF3 is an independent prognostic factor for progression-free survival of bladder cancer patients. Ectopic overexpression of ATF3 downregulated cell proliferation and invasion in bladder cancer cells in vitro, while ATF3-knockdown reversed these results. Knockdown of ATF3 upregulated EMT markers to enhance cell invasion in vitro and downregulated GDF15, NDRG1, and KAI-1 to elevate tumor growth in vivo. The activation of metformin on ATF3 and GDF15 in bladder cancer cells was blocked by SB431542, a TGFβ receptor inhibitor. ATF3 positively regulated GDF15 expression in bladder cancer cells through a feedback loop.
CONCLUSIONS: Our results identify that ATF3 is a metformin-upregulated antitumor gene. Results of Silico analysis align with cell-based studies suggesting that low ATF3/GDF15 could be a negative prognostic marker for bladder cancer.