Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093, USA.
Department of Otolaryngology‑Head and Neck Surgery, Tokai University, School of Medicine, Isehara, Kanagawa 259‑1193, Japan.
Int J Oncol. 2021 Feb;58(2):226-237. doi: 10.3892/ijo.2020.5156. Epub 2020 Dec 10.
Several comprehensive studies have demonstrated that the NOTCH pathway is altered in a bimodal manner in head and neck squamous cell carcinoma (HNSCC). In a previous study, it was found that the NOTCH4/HEY1 pathway was specifically upregulated in HNSCC and promoted epithelial‑mesenchymal transition (EMT), and that HEY1 activation supported SOX2 expression. However, the interactions in this pathway have not yet been fully elucidated. The present study investigated the NOTCH4/HEY1/SOX2 axis in HNSCC using in vitro models and the Cancer Genome Atlas (TCGA) database. To explore the association, reporter and ChIP RT‑qPCR assays using SOX2‑overexpressing (SOX2‑OE) cells were performed. The association between NOTCH4 and HEY1 was examined in the same manner using HEY1‑overexpressing (HEY1‑OE) cells. The results of the in vitro experiments indicated that HEY1 promoted EMT in the HNSCC cells. Furthermore, the overexpression of HEY1 also promoted sphere formation and increased murine xenograft tumorigenicity. Reporter assays and ChIP RT‑qPCR experiments indicated that SOX2 regulated HEY1 expression via direct binding of the HEY1 promoter. HEY1 expression significantly correlated with SOX2 expression in primary lung SCC and other SCCs using the TCGA database. HEY1 also regulated NOTCH4 expression to create a positive reciprocal feedback loop. On the whole, the present study demonstrates that HEY1 expression in HNSCC is regulated via the promotion of SOX2 and promotes EMT. The NOTCH4/HEY1 pathway is specifically upregulated via a positive reciprocal feedback loop mediated by the HEY1‑medaited regulation of NOTCH4 transcription, and SOX2 correlates with HEY1 expression in SCC from other primary sites.
几项综合研究表明，NOTCH 通路在头颈部鳞状细胞癌（HNSCC）中呈双峰模式改变。在之前的一项研究中发现，NOTCH4/HEY1 通路在 HNSCC 中特异性上调，并促进上皮-间充质转化（EMT），并且 HEY1 的激活支持 SOX2 的表达。然而，该通路中的相互作用尚未完全阐明。本研究使用体外模型和癌症基因组图谱（TCGA）数据库研究了 HNSCC 中的 NOTCH4/HEY1/SOX2 轴。为了探讨这种关联，使用 SOX2 过表达（SOX2-OE）细胞进行了报告基因和 ChIP RT-qPCR 检测。使用 HEY1 过表达（HEY1-OE）细胞以相同的方式检查了 NOTCH4 和 HEY1 之间的关联。体外实验结果表明，HEY1 促进了 HNSCC 细胞的 EMT。此外，HEY1 的过表达还促进了球体形成，并增加了小鼠异种移植肿瘤发生。报告基因检测和 ChIP RT-qPCR 实验表明，SOX2 通过直接结合 HEY1 启动子调节 HEY1 的表达。使用 TCGA 数据库，在原发性肺 SCC 和其他 SCC 中，HEY1 表达与 SOX2 表达显著相关。HEY1 还调节 NOTCH4 表达以创建正反馈回路。总的来说，本研究表明，HEY1 在 HNSCC 中的表达是通过促进 SOX2 并促进 EMT 来调节的。NOTCH4/HEY1 通路通过 HEY1 介导的 NOTCH4 转录调节的正反馈回路特异性上调，并且 SOX2 与 SCC 中其他原发性部位的 HEY1 表达相关。
