University of Illinois Cancer Center, Chicago, IL, U.S.A.
Anticancer Res. 2024 Aug;44(8):3231-3242. doi: 10.21873/anticanres.17141.
BACKGROUND/AIM: The most frequently altered epigenetic modifier in head and neck squamous carcinoma (HNSC) is the histone methyltransferase KMT2D. KMT2D catalyzes methylation of histone H3K4 resulting in open chromatin and the activation of target genes. Tumor-associated macrophages (TAMs) promote cancer growth by causing T lymphocyte exhaustion. C-C motif chemokine ligand 2 (CCL2) is a potent TAM chemotactic factor. In HNSC, TAMs have been associated with unfavorable patient outcomes and metastasis. The aim of this study was to determine the role of KMT2D in HNSC using genetically engineered in vivo models.
KMT2D protein expression was correlated with lymph node metastasis in human HNSC using immunohistochemistry. Genetically engineered KMT2D and CCL2 knockout models of HNSC were created in vivo. HNSC was characterized using qRT-PCR, histopathology, and immunohistochemistry/immunofluorescence microscopy. We also analyzed the effects of KMT2D expression on the proliferation and migration of human HNSC lines. The regulation of the CCL2 gene by KMT2D was characterized using chromatin immunoprecipitation-sequencing assay of transposase accessible chromatin-sequencing, and chromatin conformation capture-sequencing.
Human HNSC cases with high KMT2D expression exhibited significantly increased lymph node metastasis. Reduced KMT2D expression in our genetically engineered model correlated with reduced lymph node metastasis, longer latency, and slow tumor growth. CCL2 expression was decreased in KMT2D deficient HNSC, which correlated with a reduced TAM gene expression signature. Genomic experiments demonstrated that KMT2D directly targeted the CCL2 gene. A new genetically engineered in vivo model of CCL2-null HNSC was created, recapitulating the KMT2D deficient phenotype and showing a decreased T lymphocyte exhaustion signature.
KMT2D regulates CCL2-mediated immune response and metastasis in HNSC.
背景/目的：在头颈部鳞状细胞癌（HNSC）中，最常改变的表观遗传修饰物是组蛋白甲基转移酶 KMT2D。KMT2D 催化组蛋白 H3K4 的甲基化，导致染色质开放和靶基因的激活。肿瘤相关巨噬细胞（TAMs）通过引起 T 淋巴细胞衰竭促进癌症生长。C-C 基序趋化因子配体 2（CCL2）是一种有效的 TAM 趋化因子。在 HNSC 中，TAMs 与患者不良预后和转移有关。本研究旨在使用基因工程体内模型确定 KMT2D 在 HNSC 中的作用。
使用免疫组织化学法检测 KMT2D 蛋白表达与人类 HNSC 淋巴结转移的相关性。在体内建立 KMT2D 和 CCL2 基因敲除的基因工程 HNSC 模型。使用 qRT-PCR、组织病理学和免疫组织化学/免疫荧光显微镜对 HNSC 进行表征。我们还分析了 KMT2D 表达对人 HNSC 系增殖和迁移的影响。使用染色质免疫沉淀测序分析转座酶可及染色质测序和染色质构象捕获测序来研究 KMT2D 对 CCL2 基因的调控。
高 KMT2D 表达的人类 HNSC 病例表现出明显增加的淋巴结转移。我们的基因工程模型中 KMT2D 表达减少与淋巴结转移减少、潜伏期延长和肿瘤生长缓慢相关。CCL2 在 KMT2D 缺陷的 HNSC 中表达减少，与 TAM 基因表达特征减少相关。基因组实验表明，KMT2D 直接靶向 CCL2 基因。创建了一种新的 CCL2 缺失的基因工程体内 HNSC 模型，重现了 KMT2D 缺陷表型，并显示出减少的 T 淋巴细胞衰竭特征。
KMT2D 调节 HNSC 中的 CCL2 介导的免疫反应和转移。
