Background:Epigenetic alterations, including DNA methylation, play a crucial role in the development of oral squamous cell carcinoma (OSCC) by regulating the expression of tumor suppressor genes and oncogenes. This study investigated the methylation status of miR-124-3 and its role in OSCC progression.Methods:This study applied the Illumina Infinium MethylationEPIC BeadChip assay to profile >850,000 CpG sites in paired OSCC and normal tissues. The methylation data were validated by further analyzing the methylation level of miR-124-3 by using a bisulfite pyrosequencing assay. We investigated whether miR-124-3 acts as a tumor suppressor by establishing miR-124-3-overexpressing OSCC cells and subjecting them to cell proliferation, colony formation, and migration assays. Dual-luciferase reporter assay was used to validate the target genes of miR-124-3 in OSCC cells.Results:The Infinium MethylationEPIC BeadChip and bisulfite pyrosequencing assays consistently identified hypermethylation of miR-124-3 in OSCC tissues relative to normal oral tissues. It was especially notable that miR-124-3 methylation levels were markedly higher in late-stage tumors than in early-stage, and differed significantly between early-stage tumor and normal tissues, indicating that miR-124-3 methylation is an early event in OSCC development. Methylation of miR-124-3 contributes markedly to the downregulation of the gene, leading to the increased expression of its target gene, leucine-rich repeat-containing 1 (LRRC1), which is considered to be positively associated with cancer progression. Moreover, overexpression of miR-124-3 suppressed the proliferation and migration of OSCC cells, while silencing the expression of LRRC1 produced similar tumor-suppressive effects. Luciferase reporter assays confirmed that miR-124-3 directly targets the 3′ untranslated region of LRRC1 to downregulate LRRC1 expression.Conclusions:Hypermethylation-mediated downregulation of miR-124-3 results in increased LRRC1 expression, which drives OSCC progression. These findings highlight DNA methylation of miR-124-3 as a potential biomarker for the early detection of OSCC and a therapeutic target for OSCC treatments.
背景：包括DNA甲基化在内的表观遗传改变通过调控抑癌基因和癌基因的表达，在口腔鳞状细胞癌（OSCC）的发生发展中起关键作用。本研究探讨了miR-124-3的甲基化状态及其在OSCC进展中的作用。 方法：本研究采用Illumina Infinium MethylationEPIC BeadChip芯片技术，对配对OSCC组织与正常组织中的85万余个CpG位点进行甲基化谱分析。通过亚硫酸氢盐焦磷酸测序法进一步验证miR-124-3的甲基化水平。通过建立miR-124-3过表达的OSCC细胞系，并进行细胞增殖、克隆形成及迁移实验，探究miR-124-3是否发挥抑癌作用。采用双荧光素酶报告基因实验验证miR-124-3在OSCC细胞中的靶基因。 结果：Infinium甲基化芯片与亚硫酸氢盐焦磷酸测序结果一致显示，相较于正常口腔组织，OSCC组织中miR-124-3呈现高甲基化状态。值得注意的是，晚期肿瘤中miR-124-3甲基化水平显著高于早期肿瘤，且早期肿瘤与正常组织间存在显著差异，表明miR-124-3甲基化是OSCC发展过程中的早期事件。miR-124-3甲基化显著导致该基因表达下调，进而使其靶基因富含亮氨酸重复序列蛋白1（LRRC1）表达升高，而LRRC1被认为与癌症进展呈正相关。此外，过表达miR-124-3可抑制OSCC细胞的增殖与迁移，而沉默LRRC1表达也产生类似的抑癌效应。荧光素酶报告基因实验证实，miR-124-3通过直接靶向LRRC1的3′非翻译区来下调其表达。 结论：高甲基化介导的miR-124-3表达下调导致LRRC1表达升高，从而驱动OSCC进展。这些发现提示，miR-124-3的DNA甲基化可作为OSCC早期检测的潜在生物标志物及治疗靶点。
肿瘤(癌症)患者之家