Ten-11 易位 2 (TET2) 和 5-甲基胞嘧啶 (5mC) 转化为 5-羟甲基胞嘧啶 (5hmC) 在结外自然杀伤/T 细胞淋巴瘤 (ENKTL) 发展中的生物学作用仍不清楚。采用免疫组织化学（IHC）染色法检测112例ENKTL组织标本中5mC和5hmC的水平。随后，在 ENKTL 细胞系中构建 TET2 敲低和过表达细胞模型。生化分析用于评估用 L-抗坏血酸钠盐 (LAASS) 处理或未处理的细胞的增殖、凋亡、细胞周期和单克隆形成。使用斑点印迹检测基因组5mC和5hmC的水平。此外，利用ILLUMINA 850k甲基化芯片分析TET2调控基因的变化。 RNA-Seq 用于分析 TET​​2 调控的差异表达基因。 5hmC的整体水平显着降低，而5mC在ENKTL组织中高表达。 TET2 蛋白表达与 5mC/5hmC 的比率呈负相关 (p < 0.0001)。 5mC/5hmC状态与疾病部位、临床分期、PINK评分和Ki-67指数以及5年OS相关。 TET2敲低延长了DNA合成周期，增加了肿瘤细胞的克隆能力，增加了ENKTL细胞中5mC的水平并降低了5hmC的水平。而TET2的过度表达则呈现相反的效果。此外，用 LAASS 处理 ENKTL 细胞显着诱导 ENKTL 细胞凋亡。这些结果表明，TET2 通过调节 5mC 和 5hmC 在 ENKTL 发育中发挥重要作用，并可能作为 ENKTL 的新型治疗靶点。© 2024 John Wiley

The biological role of Ten-11 translocation 2 (TET2) and the conversion of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) in the development of extra-nodal natural killer/T-cell lymphoma (ENKTL) remains unclear. The level of 5mC and 5hmC was detected in 112 cases of ENKTL tissue specimens by immunohistochemical (IHC) staining. Subsequently, TET2 knockdown and the overexpression cell models were constructed in ENKTL cell lines. Biochemical analyses were used to assess proliferation, apoptosis, cell cycle and monoclonal formation in cells treated or untreated with L-Ascorbic acid sodium salt (LAASS). Dot-Blots were used to detect levels of genome 5mC and 5hmC. Additionally, the ILLUMINA 850k methylation chip was used to analyze the changes of TET2 regulatory genes. RNA-Seq was used to profile differentially expressed genes regulated by TET2. The global level of 5hmC was significantly decreased, while 5mC was highly expressed in ENKTL tissue. TET2 protein expression was negatively correlated with the ratio of 5mC/5hmC (p < 0.0001). The 5mC/5hmC status were related to the site of disease, clinical stage, PINK score and Ki-67 index, as well as the 5-year OS. TET2 knockdown prolonged the DNA synthesis period, increased the cloning ability of tumor cells, increased the level of 5mC and decreased the level of 5hmC in ENKTL cells. While overexpression of TET2 presented the opposite effect. Furthermore, treatment of ENKTL cells with LAASS significantly induced ENKTL cell apoptosis. These results suggest that TET2 plays an important role in ENKTL development via regulation of 5mC and 5hmC and may serve as a novel therapeutic target for ENKTL.© 2024 John Wiley & Sons Ltd.