PO.IM02.06 · 免疫学
KMT2C 和 KMT2D 在调节子宫内膜癌肿瘤免疫微环境中的作用
Role of KMT2C and KMT2D in modulating tumor immune microenvironment of endometrial cancer
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
背景：近期子宫内膜癌（EC）的分子分类提高了预后准确性并有助于指导靶向治疗。在频繁突变的因子中包括表观遗传调控因子，如赖氨酸甲基转移酶 KMT2C 和 KMT2D，它们在增强子位点对 H3K4 进行单甲基化，其功能缺失（LOF）突变与基因组不稳定、染色质可及性改变和免疫逃逸增加相关。尽管绝经后 EC 患者中 CD8+ T 细胞浸润增加和 PDL1 高表达与不良预后相关，但表观遗传突变对免疫信号的影响仍知之甚少。Cao 等人的泛癌分析提示，低 KMT2C 表达可能降低免疫抑制并带来更好的免疫治疗应答，在其他癌症中也观察到类似模式，提示其在调节免疫应答中的潜在作用。
方法：使用 CRISPR 技术在 12Z 和 HEC1a 细胞中生成 KMT2C 和 KMT2D 敲除，并使用这些细胞的全细胞裂解物进行免疫印迹分析。接下来，对 KMT2D 敲除小鼠组织进行免疫组织化学以观察特定免疫标志物。最后，进行流式细胞术分析以了解肿瘤微环境的构成并探索各种免疫细胞作用的差异。
结果：TCGA 数据库显示，当 KMT2C 发生改变时，免疫因子如 IFN-G 和 CTLA-4 上调。CRISPR 敲除细胞的免疫印迹分析显示 KMT2C 敲除细胞中 PDL1 表达上调。此外，KMT2D 敲除小鼠组织的免疫组织化学显示 CD8+ 表达降低。随后，KMT2D 敲除小鼠组织的流式细胞术分析显示髓源性抑制细胞增加、CD8+ 和 CD4+ 细胞减少，提示免疫抑制性环境。
结论：总体而言，这些发现凸显了 KMT2C 和 KMT2D 突变对肿瘤免疫微环境的作用，并支持它们作为子宫内膜癌中 ICI 应答性预测生物标志物的潜力。鉴于免疫治疗临床疗效不一，理解肿瘤微环境的复杂性至关重要。未来研究将侧重于在 KMT2C 敲除小鼠中重现这些结果，并进一步理解 KMT2C 和 KMT2D 改变在塑造免疫微环境中的潜力。
查看英文原文 English abstract
BACKGROUND: Recent molecular classifications of Endometrial Cancer (EC) have enhanced prognostic accuracy and helped guide targeted therapies. Among frequently mutated factors are epigenetic regulators like lysine methyltransferases KMT2C and KMT2D which monomethylate H3K4 at enhancer sites and their loss of function (LOF) mutation is associated with genomic instability, altered chromatin accessibility and increased immune evasion. Although increased CD8+ T cells infiltration and high PDL1 expression in postmenopausal EC patients is linked to poor prognosis, the impact of epigenetic mutation on immune signaling remains poorly understood. Pan-cancer analysis by Cao et al suggests that low KMT2C expression may reduce immunosuppressive and better immunotherapy responses, with similar patterns seen in other cancers suggesting a potential role in modulating immune response.
METHODS: CRISPR technology was used to generated KMT2C and KMT2D knockouts in 12Z and HEC1a cells and whole cell lysates of these cells were used for immunoblotting analysis. Next, Immunohistochemistry on KMT2D KO mouse tissues were performed to look at specific immune markers. Finally, flow cytometry analysis was done to understand the makeup of the tumor microenvironment and explore the differences in the role of various immune cells.
RESULTS: TCGA database showed upregulation of immune factors like IFN-G and CTLA-4 when KMT2C is altered. Immunoblotting analysis of the CRISPR knockout cells showed upregulation of PDL1 expression in KMT2C knockout cells. Further, Immunohistochemistry of KMT2D KO mouse tissues showed decreased CD8+ expression. Following this, flow cytometry analysis of KMT2D KO mouse tissues showed increased myeloid derived suppressor cells and decreased CD8+ and CD4+ cells which indicates an immunosuppressive environment.
CONLCUSION: Overall, these findings highlight the role of KMT2C and KMT2D mutations on the tumor immune microenvironment and support their potential as predictive biomarker for ICI responsiveness in endometrial cancer. The mixed clinical efficacy of immunotherapies, it is critical to understand the intricacies of the tumor microenvironment. Future studies will focus on replicating the results in KMT2C KO mice and further understand the potential of KMT2C and KMT2D alteration in shaping the immune microenvironment.
利益披露 Disclosure
S. Ganesh, None..
S. Pukhrambam, None..
J. Ali, None..
S. Hughes, None.