KDM4A的结构、功能及其在肿瘤中作用的研究进展

组蛋白甲基化是一种重要的表观遗传修饰,而赖氨酸特异性去甲基化酶4A(KDM4A,也称JMJD2A)能特异性催化组蛋白赖氨酸残基的去甲基化过程,从而调节染色质的结构和基因转录.近年来研究发现,KDM4A参与调控了细胞增殖、分化、发育、代谢等多种重要的生物学进程,其功能异常也和肿瘤等疾病的发生发展密切相关,成为未来肿瘤治疗...     

组蛋白去甲基化酶KDM3B结构、功能及其相关疾病研究进展

表观遗传学是研究在DNA序列不变的前提下,其他机制异常引起基因表达改变并可遗传的学科。组蛋白甲基化/去甲基化修饰是表观遗传学的重要调控机制之一,是甲基化酶和去甲基化酶动态相互作用的结果,其中H3K9的甲基化和去甲基化是近年来研究最深入的组蛋白修饰之一。组蛋白去甲基化酶KDM3B包含一个JmjC结构域,并具有固有的H3K9去甲基化活性,能够特异性去除H3K9me1/2甲基化修饰,调控基因转录、DNA损伤修复,参与细胞增殖、细胞凋亡、干细胞干性维持、肿瘤和遗传病发生发展等。该文就组蛋白去甲基化酶KDM3B的结构、作用机制、生物学功能及其成为一个临床研究和治疗的潜在药理学靶点的可能性作一综述。     

组蛋白去甲基化酶与肿瘤发生

组蛋白甲基化修饰是一个可逆的动态的调节过程。甲基化和/或去甲基化状态与表观遗传、转录调控和维持基因组完整性等密切相关。组蛋白甲基化状态异常会直接或间接影响各种生理和病理过程。已知组蛋白去甲基化酶包括赖氨酸特异性去甲基化酶（LSD）家族和含JmjC结构域的JMJD家族。研究发现,两者与肿瘤的发生均有着密切的关系。本文总结了组蛋白去甲基化酶在组蛋白甲基化修饰及肿瘤研究方面的最新进展,为组蛋白修饰的功能及肿瘤诊断、治疗、预后监测等研究提供新思路。在胃癌、乳腺癌、结肠癌等常见肿瘤中,组蛋白去甲基化酶可改变组蛋白的甲基化水平或者直接作用于癌基因,也可调节microRNA或转录因子等,促进或抑制肿瘤的发生发展与影响肿瘤的预后。     

赖氨酸特异性组蛋白去甲基化酶1与白血病的研究进展

表观遗传学是后基因组时代兴起的一门新学科,它使人们认识到包括DNA甲基化、组蛋白修饰、染色质重塑及非编码RNA调控在内的修饰也可以记载遗传信息;并且许多表观遗传改变是可逆的,对表观遗传修饰和调控的研究已成为生命科学的热点和发展前沿。2004年发现的赖氨酸特异性组蛋白去甲基化酶1(LSD1)是第一个真正意义上的组蛋白赖氨酸去甲基化酶,使人们认识到组蛋白甲基化是一个动态的过程,通过组蛋白甲基转移酶和去甲基化酶的相互作用,动态地调控基因转录的激活和抑制等生物学过程。这重新定义了组蛋白甲基化,同时也为进一步深入研究组蛋白修饰提供了新的途径。我们在此简要介绍LSD1的结构与功能、LSD1与白血病的关系,LSD1在白血病的发生和发展中发挥重要作用,是一个潜在的治疗白血病的靶基因。     

组蛋白去甲基化酶KDM7家族在脑疾病中研究进展

组蛋白去甲基化酶KDM7家族包括KDM7A、KDM7B、KDM7C三种蛋白,主要通过去除与转录沉默相关的特定组蛋白赖氨酸甲基化修饰,进而对基因转录发挥调控作用。目前,对KDM7家族的研究主要集中于其在神经分化、肿瘤发生发展等过程中的作用,而对其在脑神经疾病中的作用却知之甚少。本文从该蛋白家族表观遗传调控机制、结构生物学及其在脑神经疾病中的作用等方面进行了综述,以期为研究其在脑神经疾病中的功能机制提供参考,为理解脑神经疾病分子病理机制以及探索基于该机制的有效治疗靶点带来新的启示。     

组蛋白去甲基化酶研究进展

组蛋白甲基化是一种重要的表观遗传修饰方式,2004年组蛋白去甲基化酶的发现使人们认识到组蛋白的甲基化也是一个可逆的修饰过程,并由此掀起了人们对组蛋白去甲基化研究的热潮。该文主要从近年来研究人员在组蛋白去甲基化酶的鉴定、组蛋白去甲基化酶的功能研究等方面取得的进展进行阐述,并就该方面的研究进行展望。     

组蛋白去甲基化酶KDM5A调控H3K4me3参与神经管畸形发生的分子机制

神经管畸形(NTDs)的病因与防治是出生缺陷领域研究的重点,叶酸可以预防神经管畸形但其机制不明。本文借助低叶酸细胞模型和低叶酸NTDs小鼠模型通过染色质免疫共沉淀、Cut&Tag等技术,探讨了组蛋白去甲基化酶lysine demethylase 5A(KDM5A)及其调控的下游组蛋白H3K4me3修饰在叶酸缺乏导致的NTDs发生中的潜在分子机制。结果显示,低叶酸的细胞模型中,qRT-PCR、Western印迹结果显示,KDM5A分子表达明显下降(P<0.05)。作为组蛋白H3K4me3调控的上游关键酶,进一步通过染色质免疫共沉淀ChIP、ChIP-qPCR实验证实,叶酸缺乏下组蛋白H3K4me3在神经发育基因Axin2和Atoh1基因启动子区富集增加(P<0.05)。通过构建KDM5A基因敲除细胞模型,借助Cut&Tag试验证实,KDM5A基因敲除后H3K4me3主要富集在神经发育基因上。最后在低叶酸导致的NTDs小鼠模型的脑组织中,RT-qPCR、Western印迹以及ChIP-qPCR实验显示,E9.5 d的NTDs胎鼠脑组织中KDM5A表达下降(P&l...     

组蛋白去甲基化酶LSD1及其生物学功能

赖氨酸特异性组蛋白去甲基化酶1(Lysine specific demethylase 1, LSD1) 的发现, 表明组蛋白的甲基化修饰是一个动态可调节的过程。结构分析显示, LSD1 是一个黄素腺嘌呤二核苷酸(Flavin adenine dinulcleotide, FAD) 依赖性胺氧化酶, 它能够特异性脱去单甲基化和二甲基化组蛋白H3第4位赖氨酸(H3K4) 和H3K9 位点上的甲基基团。功能研究显示, LSD1 定位于细胞核内, 调控着基因转录的激活和抑制, 被誉为细胞深处的基因“开关”, 在胚胎发育和肿瘤发生过程中起着重要的作用。文章主要综述了LSD1 的结构、作用机制及其调控作用研究的新进展。     

重组蛋白KDM4D对水牛成纤维细胞生长及组蛋白甲基化修饰的影响

本研究旨在探讨重组蛋白赖氨酸特异性去甲基化酶4D(lysine K-specific demethylase 4D, KDM4D)对水牛成纤维细胞(buffalo fetal fibroblasts, BFFs)生长及组蛋白甲基化修饰的影响,为提高水牛体细胞重编程效率提供理论基础。首先,使用不同浓度的重组蛋白KDM4D处理BFFs,摸索出最适宜的处理浓度和处理时间。其次,采用实时定量PCR技术和EdU方法检测重组蛋白KDM4D对BFFs增殖凋亡的影响。最后,使用细胞免疫荧光和Western blot对组蛋白H3第9位赖氨酸三甲基化(histone 3 lysine 9 trimethylation, H3K9me3)修饰水平和异染色质蛋白1α(heterochromatin protein 1α,HP1α)基因的表达水平进行检测。结果发现,适宜浓度的重组蛋白KDM4D(0.10μg/mL)处理36 h对BFFs形态无明显影响,可以显著提高细胞活力(P<0.05)。实时定量PCR分析结果显示,与对照组相比,重组蛋白KDM4D可以显著提高细胞周期蛋白依赖性激酶4(cyclin dep...     

组蛋白甲基化研究进展

组蛋白甲基化是表观遗传修饰方式中的一种,参与异染色质形成、基因印记、X染色体失活和基因转录调控.组蛋白甲基化过程的异常参与多种肿瘤的发生.既往认为组蛋白甲基化是稳定的表观遗传标记,而组蛋白去甲基化酶的发现对这一观点提出了挑战,也为进一步深入研究组蛋白修饰提供新的途径.     

Sumoylation of the histone demethylase KDM4A is required for binding to tumor suppressor p53 in HCT116 colon cancer cell lines

The histone demethylase lysine-specific demethylase 4A (KDM4A/Jmjd2A) has diverse functions, including involvement in gene regulation and cell cycle, and plays an oncogenic role in cancer cells. The modulation of KDM4A through post-translational modifications remains unclear. Here, we show that small ubiquitin-like modifier (SUMO) 1-mediated modification of KDM4A was required for interaction with tumor suppressor p53. Our data revealed that KDM4A is mainly sumoylated at lysine residue 471. However, the SUMO modification resulted in little change in subcellular localization, demethylase activity, or protein stability of KMD4A. Intriguingly, co-immunoprecipitation data revealed that sumoylation-defective mutants of KDM4A had a lower binding ability with p53 compared to that of wild-type KDM4A, suggesting a positive role for sumoylation in the interaction between KDM4A and p53. Together, these data suggest that KDM4A is post-translationally modified by SUMO, and this sumoylation may be a novel regulatory switch for controlling the interplay between KDM4A and p53.     

Regulation of Transient Site-specific Copy Gain by MicroRNA

Intra-tumor copy number heterogeneity is commonly observed in cancer; however, the molecular mechanisms that contribute to heterogeneity remain poorly understood. Up-regulation of the histone demethylase KDM4A promotes transient site-specific copy gain (TSSG) in cells; therefore, uncovering how KDM4A levels are controlled is important for understanding the regulation of copy number heterogeneity. Here, we demonstrate that KDM4A is regulated by hsa-mir-23a-3p, hsa-mir-23b-3p, and hsa-mir-137. Altering expression of these microRNAs (miRNAs) regulates KDM4A-dependent TSSG. miRNA inhibition promoted copy gains and increased expression of the drug-resistant oncogene CKS1B, which was further substantiated in primary breast tumors. Consistent with increased CKS1B expression, miRNA inhibition reduced breast cancer cell sensitivity to cisplatin. Our data identify these miRNAs as regulators of TSSG and copy gains of a drug resistance gene.     

KDM5D inhibit epithelial-mesenchymal transition of gastric cancer through demethylation in the promoter of Cul4A in male

Gastric cancer is one of the top causes of cancer-related death around the world, and poor prognosis of gastric cancer is due to the lack of early detection and effective treatment especially in male. Here, we first revealed the role of histone lysine-specific demethylase 5D (KDM5D) in gastric cancer in male. KDM5D was associated with the metastasis of gastric cancer because of its critical role in the epithelial-mesenchymal transition of gastric cancer cells. Downregulation of KDM5D in gastric cancer cells significantly increase the number of migrated or invaded cells due to the increasing expressions of mesenchymal markers. Downregulation of KDM5D also promotes tumor formation of gastric cancer cell in vivo. For mechanism, downregulation of KDM5D could inhibit the demethylation in the promoter of CUL4A, which lead to the increasing expression of ZEB1 and decreasing expressions of p21 and p53. Collectively, KDM5D performed its role in metastasis of gastric cancer through demethylation in the promoter of CUL4A, and it suggested us a novel target in gastric cancer treatment in male.     

Extracellular vesicles-encapsulated let-7i shed from bone mesenchymal stem cells suppress lung cancer via KDM3A/DCLK1/FXYD3 axis

Accumulating evidence has suggested that extracellular vesicles (EVs) play a crucial role in lung cancer treatment. Thus, we aimed to investigate the modulatory role of bone marrow mesenchymal stem cell (BMSC)-EV-derived let-7i and their molecular mechanism in lung cancer progression. Microarray-based analysis was applied to predict lung cancer-related miRNAs and their downstream genes. RT-qPCR and Western blot analyses were conducted to determine Let-7i, lysine demethylase 3A (KDM3A), doublecortin-like kinase 1 (DCLK1) and FXYD domain-containing ion transport regulator 3 (FXYD3) expressions, after which dual-luciferase reporter gene assay and ChIP assay were used to identify the relationship among them. After loss- and gain-of-function assays, the effects of let-7i, KDM3A, DCLK1 and FXYD3 on the biological characteristics of lung cancer cells were assessed. Finally, tumour growth in nude mice was assessed by xenograft tumours in nude mice. Bioinformatics analysis screened out the let-7i and its downstream gene, that is KDM3A. The findings showed the presence of a high expression of KDM3A and DCLK1 and reduced expression of let-7i and FXYD3 in lung cancer. KDM3A elevated DCLK1 by removing the methylation of H3K9me2. Moreover, DCLK1 suppressed the FXYD3 expression. BMSC-EV-derived let-7i resulted in the down-regulation of KDM3A expression and reversed its promoting role in lung cancer development. Consistently, in vivo experiments in nude mice also confirmed that tumour growth was suppressed by the BMSC-EV-derived let-7i. In conclusion, our findings demonstrated that the BMSC-EV-derived let-7i possesses an inhibitory role in lung cancer progression through the KDM3A/DCLK1/FXYD3 axis, suggesting a new molecular target for lung cancer treatment.     

长寿蛋白SIRT6在肿瘤发生发展中的作用

SIRT6作为组蛋白去乙酰化转移酶(Histone deacetylases,HDACs)第三家族长寿蛋白(Sirtuins,SIRTs)中的一员,具有多种催化酶活性,且在抗衰老、染色质调节、转录调控、糖脂代谢、DNA损伤修复等生物学过程中起着重要的作用。近年来的证据表明,SIRT6的表达与肿瘤的发生发展密切相关,且在多种肿瘤中起着关键的调节作用,比如肝癌、肺癌、乳腺癌和生殖系统肿瘤等。但是由于SIRT6功能的多样性,及其上下游信号通路的复杂性,SIRT6在肿瘤中可能扮演着双重角色。在大多数情况下,SIRT6扮演着抑癌基因的角色,少数情况下,SIRT6却又发挥着促癌作用。本文结合目前本实验室的研究,阐述了近几年来关于SIRT6在多种肿瘤发生及发展中的最新发现,总结了其作用机制,并对其研究及应用前景进行了展望。     

Knockdown of KDM1A suppresses tumour migration and invasion by epigenetically regulating the TIMP1/MMP9 pathway in papillary thyroid cancer

Epigenetic dysregulation plays an important role in cancer. Histone demethylation is a well‐known mechanism of epigenetic regulation that promotes or inhibits tumourigenesis in various malignant tumours. However, the pathogenic role of histone demethylation modifiers in papillary thyroid cancer (PTC), which has a high incidence of early lymphatic metastasis, is largely unknown. Here, we detected the expression of common histone demethylation modifiers and found that the histone H3 lysine 4 (H3K4) and H3 lysine 9 (H3K9) demethylase KDM1A (or lysine demethylase 1A) is frequently overexpressed in PTC tissues and cell lines. High KDM1A expression correlated positively with age <55 years and lymph node metastasis in patients with PTC. Moreover, KDM1A was required for PTC cell migration and invasion. KDM1A knockdown inhibited the migration and invasive abilities of PTC cells both in vitro and in vivo. We also identified tissue inhibitor of metalloproteinase 1 (TIMP1) as a key KDM1A target gene. KDM1A activated matrix metalloproteinase 9 (MMP9) through epigenetic repression of TIMP1 expression by demethylating H3K4me2 at the TIMP1 promoter region. Rescue experiments clarified these findings. Altogether, we have uncovered a new mechanism of KDM1A repression of TIMP1 in PTC and suggest that KDM1A may be a promising therapeutic target in PTC.