通过 LPS-TET3-HOXB2 信号轴在食管鳞状细胞癌中诱导肿瘤干性的表观遗传。

BACKGROUND: Esophageal squamous cell cancer (ESCC) is one kind of frequent digestive tumor. The inflammatory environment plays an important role in the tumorigenesis and development of ESCC. Cancer stem cells are a small group of tumor cells with stem cell characteristics, which can potentially hinder the tumor management and treatment. METHODS: ELISA was performed to detect the lipopolysaccharide concentration in cancer tissues. qPCR, Western blot, FACS, Immunohistochemistry, Immunofluorescence and Dot blot were applied to detect target genes expression. CCK-8, Colony-formation, Transwell, Sphere and Xenograft were conducted to investigate the function of cells, influenced by risk factors. The survival curve was drawn with the Kaplan-Meier product limit estimator. Nano-hmC-Seal-seq was utilized to detect the downstream target of TET3. ChIP-qPCR was adopted to demonstrate the transcriptional regulation of stem cell-associated genes by HOXB2. RESULTS: Lipopolysaccharide concentration was significantly up-regulated in ESCC. High concentration of lipopolysaccharide stimulation induced the stemness of ESCC cells. TET3 expression was elevated with lipopolysaccharide stimulation via p38/ERK-MAPK pathway in ESCC and negatively correlated with patients' survival. TET3 induced the stemness of ESCC cells. Nano-hmC-Seal-seq showed that TET3 overexpression led to a significant increase in 5hmC levels of HOXB2 gene region, which was thus identified as the downstream target of TET3. The binding of HOXB2 to NANOG and cMYC was verified by ChIP-qPCR. CONCLUSIONS: Lipopolysaccharide served as a tumor promotor in ESCC by inducing cancer cell stemness through the activation of a LPS-TET3-HOXB2 signaling axis, which might provide a novel therapeutic strategy for ESCC. Video Abstract.

背景：食管鳞状细胞癌（ESCC）是一种常见的消化道肿瘤。炎症微环境在 ESCC 的发生和发展中起着重要作用。癌症干细胞是一群具有干细胞特征的肿瘤细胞，它们可能会阻碍肿瘤的管理和治疗。

方法：采用 ELISA 法检测癌组织中脂多糖浓度。采用 qPCR、Western blot、FACS、免疫组化、免疫荧光和斑点印迹法检测靶基因表达。采用 CCK-8、集落形成、Transwell、球状体和异种移植实验研究细胞功能，受危险因素影响。采用 Kaplan-Meier 乘积限估计法绘制生存曲线。采用纳米 hmC-Seal-seq 检测 TET3 的下游靶标。采用 ChIP-qPCR 证明 HOXB2 对干细胞相关基因的转录调控。

结果：ESCC 中脂多糖浓度显著上调。高浓度脂多糖刺激通过 p38/ERK-MAPK 通路诱导 ESCC 细胞的干性。TET3 表达随着脂多糖刺激而升高，与患者的生存呈负相关。TET3 诱导 ESCC 细胞的干性。纳米 hmC-Seal-seq 显示，TET3 过表达导致 HOXB2 基因区域的 5hmC 水平显著增加，从而确定为 TET3 的下游靶标。通过 ChIP-qPCR 验证了 HOXB2 与 NANOG 和 cMYC 的结合。

结论：脂多糖通过激活 LPS-TET3-HOXB2 信号轴诱导癌细胞干性，在 ESCC 中充当肿瘤促进剂，这可能为 ESCC 提供一种新的治疗策略。视频摘要。