Department of Pancreatic Surgery, Fudan University Shanghai Cancer Center, China; Department of Oncology, Shanghai Medical College, Fudan University, China; Pancreatic Cancer Institute, Fudan University, Shanghai Pancreatic Cancer Institute, Shanghai, China.
Department of Pancreatic Surgery, Fudan University Shanghai Cancer Center, China; Department of Oncology, Shanghai Medical College, Fudan University, China; Pancreatic Cancer Institute, Fudan University, Shanghai Pancreatic Cancer Institute, Shanghai, China.
Cancer Lett. 2021 Feb 28;499:265-278. doi: 10.1016/j.canlet.2020.11.023. Epub 2020 Nov 21.
Constitutive ERK1/2 activation has been frequently observed in pancreatic adenocarcinoma (PDAC). How ERK1/2 activation status been potentiated and maintained by epigenetic mechanisms has seldom been discussed in PDAC. In this study, we first examined the expression status of p-ERK1/2 in PDAC tissues by immunohistochemical staining and then screened possible epigenetic factors that displayed different expression status between p-ERK1/2 high and low groups by RNA profiling, and found that SETD8 displayed an increased expressional pattern in p-ERK1/2 patient group. Then the impact of SETD8 on the proliferation of PDAC cells were investigated on the basis of gain or loss-of-function assays. RNA sequencing assays were performed to screen potential SETD8 downstream targets that contribute to ERK1/2 activation. Mass spectrometry and transcriptional analysis, including dual-luciferase assay and chromatin immunoprecipitation assay (ChIP), were used to explore the molecular mechanisms that governing SETD8-mediated ERK1/2 activation. In vitro cell line studies and in vivo xenograft mouse model studies indicated that SETD8 promoted cell proliferation and increased tumor formation capacity of PDAC cell lines. Mechanism explorations uncovered that SETD8 suppressed the expression of DUSP10, which was responsible for dephosphorylation of ERK1/2. Mass spectrometry and transcriptional analysis results demonstrated that STAT3 interacted with SETD8 and recruited SETD8 to the promoter region of DUSP10, leading to epigenetic silencing of DUSP10 and the resultant activation of ERK1/2. In conclusion, SETD8 interacts with STAT3 on DUSP10 promoter region and epigenetically silences DUSP10 expression. Decreased DUSP10 expression in PDAC potentiates activation of ERK1/2 phosphorylation, resulting in unfavorable prognosis of PDAC.
ERK1/2 的组成性激活在胰腺导管腺癌 (PDAC) 中经常观察到。ERK1/2 的激活状态如何通过表观遗传机制被增强和维持在 PDAC 中很少被讨论。在这项研究中，我们首先通过免疫组织化学染色检查了 PDAC 组织中 p-ERK1/2 的表达状态，然后通过 RNA 谱筛选可能显示 p-ERK1/2 高和低组之间不同表达状态的表观遗传因子，并发现 SETD8 在 p-ERK1/2 患者组中显示出增加的表达模式。然后，在功能获得或丧失测定的基础上，研究 SETD8 对 PDAC 细胞增殖的影响。进行 RNA 测序测定，以筛选有助于 ERK1/2 激活的潜在 SETD8 下游靶标。质谱和转录分析，包括双荧光素酶测定和染色质免疫沉淀测定 (ChIP)，用于探索调节 SETD8 介导的 ERK1/2 激活的分子机制。体外细胞系研究和体内异种移植小鼠模型研究表明，SETD8 促进 PDAC 细胞系的细胞增殖和增加肿瘤形成能力。机制探索发现，SETD8 抑制 DUSP10 的表达，这是 ERK1/2 去磷酸化的原因。质谱和转录分析结果表明，STAT3 与 SETD8 相互作用，并将 SETD8 募集到 DUSP10 启动子区域，导致 DUSP10 的表观遗传沉默和 ERK1/2 的激活。总之，SETD8 在 DUSP10 启动子区域与 STAT3 相互作用，并表观遗传沉默 DUSP10 的表达。PDAC 中 DUSP10 表达的减少增强了 ERK1/2 磷酸化的激活，导致 PDAC 的预后不良。
