高甲基化诱导的ITGA4沉默通过上调SNX5促进口腔鳞状细胞癌进展

摘要(中文译文)

表观遗传修饰，尤其是DNA甲基化，在口腔癌中发挥着越来越重要的作用。然而，其在口腔鳞状细胞癌（OSCC）进展中的具体作用仍不清楚。本研究利用Shiny甲基化分析资源工具（SMART）数据库（https://smart.embl.de/smart/change_mode.cgi）鉴定与OSCC相关的甲基化驱动基因。在鉴定出的候选基因中，整合素亚基α4（ITGA4）在头颈癌中表现出显著升高的甲基化水平。甲基化特异性PCR检测显示，与正常永生化人口腔角质形成细胞（iNOK）相比，ITGA4在OSCC细胞中高度甲基化。此外，与正常iNOK细胞相比，OSCC细胞系中ITGA4的mRNA表达水平显著降低。ITGA4过表达显著抑制了FaDu和YD-15细胞的细胞增殖、迁移能力和集落形成能力，并诱导细胞凋亡。在蛋白质组学分析中，ITGA4抑制了分选连接蛋白5（SNX5）的表达，该蛋白与癌症进展相关。siRNA介导的SNX5敲低显著抑制了FaDu和YD-15细胞的细胞增殖、迁移和集落形成。此外，在鸡胚绒毛尿囊膜异种移植模型中，ITGA4过表达或小干扰SNX5显著抑制了OSCC肿瘤生长和血管生成。总之，这些研究结果表明，ITGA4通过下调SNX5在OSCC中发挥抑癌作用，并提示ITGA4可能作为OSCC有价值的预后生物标志物和潜在治疗靶点。

Abstract

Epigenetic modifications, especially DNA methylation, play an increasingly important role in oral cancer. However, their specific contributions to the progression of oral squamous cell carcinoma (OSCC) remain unclear. The present study used the Shiny Methylation Analysis Resource Tool (SMART) database (https://smart.embl.de/smart/change_mode.cgi) to identify methylation‑driven genes associated with OSCC. Among the identified candidates, integrin subunit α4 (ITGA4) exhibited significantly elevated methylation levels in head and neck cancers. A methylation‑specific PCR assay showed that ITGA4 is highly methylated in OSCC cells compared with normal immortalized human normal oral keratinocyte (iNOK) cells. Additionally, the mRNA expression levels of ITGA4 were significantly lower in OSCC cell lines compared with normal iNOK cells. ITGA4 overexpression markedly inhibited the cell proliferation, migratory ability and capacity of colony formation and induced apoptosis in FaDu and YD‑15 cells. In proteomic analysis, ITGA4 suppressed the expression of Sorting Nexin 5 (SNX5), a protein linked to cancer progression. siRNA‑mediated knockdown of SNX5 importantly inhibited cell proliferation, migration, and colony formation in FaDu and YD‑15 cells. Moreover, in a chick chorioallantoic membrane xenograft model, overexpression of ITGA4 or small interfering SNX5 significantly inhibited OSCC tumor growth and angiogenesis . Collectively, these findings demonstrated that ITGA4 acts as a tumor suppressor in OSCC by downregulating SNX5 and suggested that ITGA4 may serve as a valuable prognostic biomarker and potential therapeutic target for OSCC.

如何引用