Department of Gastroenterology, The First Affiliated Hospital, Jinan University, Guangzhou, 510632, China.
Department of Gastroenterology, Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, 533000, China.
Oncol Res. 2023 Jun 27;31(4):515-541. doi: 10.32604/or.2023.029101. eCollection 2023.
The dysregulation of exosomal microRNAs (miRNAs) plays a crucial role in the development and progression of cancer. This study investigated the role of a newly identified serum exosomal miRNA miR-4256 in gastric cancer (GC) and the underlying mechanisms. The differentially expressed miRNAs were firstly identified in serum exosomes of GC patients and healthy individuals using next-generation sequencing and bioinformatics. Next, the expression of serum exosomal miR-4256 was analyzed in GC cells and GC tissues, and the role of miR-4256 in GC was investigated by and experiments. Then, the effect of miR-4256 on its downstream target genes HDAC5/p16 was studied in GC cells, and the underlying mechanisms were evaluated using dual luciferase reporter assay and Chromatin Immunoprecipitation (ChIP). Additionally, the role of the miR-4256/HDAC5/p16 axis in GC was studied using and experiments. Finally, the upstream regulators SMAD2/p300 that regulate miR-4256 expression and their role in GC were explored using experiments. miR-4256 was the most significantly upregulated miRNA and was overexpressed in GC cell lines and GC tissues; and results showed that miR-4256 promoted GC growth and progression. Mechanistically, miR-4256 enhanced HDAC5 expression by targeting the promoter of the HDAC5 gene in GC cells, and then restrained the expression of p16 through the epigenetic modulation of HDAC5 at the p16 promoter. Furthermore, miR-4256 overexpression was positively regulated by the SMAD2/p300 complex in GC cells. Our data indicate that miR-4256 functions as an oncogene in GC via the SMAD2/miR-4256/HDAC5/p16 axis, which participates in GC progression and provides novel therapeutic and prognostic biomarkers for GC.
外泌体 microRNAs（miRNAs）的失调在癌症的发生和发展中起着关键作用。本研究探讨了一种新鉴定的血清外泌体 miRNA miR-4256 在胃癌（GC）中的作用及其潜在机制。首先使用下一代测序和生物信息学方法鉴定 GC 患者和健康个体血清外泌体中的差异表达 miRNA。接下来，分析 GC 细胞和 GC 组织中血清外泌体 miR-4256 的表达，并通过 和 实验研究 miR-4256 在 GC 中的作用。然后，在 GC 细胞中研究 miR-4256 对其下游靶基因 HDAC5/p16 的影响，并通过双荧光素酶报告基因检测和染色质免疫沉淀（ChIP）评估其潜在机制。此外，还通过 和 实验研究了 miR-4256/HDAC5/p16 轴在 GC 中的作用。最后，通过 实验探讨了调节 miR-4256 表达的上游调节因子 SMAD2/p300 及其在 GC 中的作用。miR-4256 是上调最显著的 miRNA，在 GC 细胞系和 GC 组织中过度表达； 和 结果表明，miR-4256 促进 GC 的生长和进展。在机制上，miR-4256 通过靶向 HDAC5 基因启动子增强 GC 细胞中的 HDAC5 表达，然后通过 HDAC5 在 p16 启动子上的表观遗传修饰抑制 p16 的表达。此外，miR-4256 过表达在 GC 细胞中受到 SMAD2/p300 复合物的正向调节。我们的数据表明，miR-4256 通过 SMAD2/miR-4256/HDAC5/p16 轴在 GC 中作为癌基因发挥作用，参与 GC 进展，并为 GC 提供新的治疗和预后生物标志物。
