Human glioblastoma-initiating cells invade specifically the subventricular zones and olfactory bulbs of mice after striatal injection

In patients with glioblastoma multiforme, recurrence is the rule despite continuous advances in surgery, radiotherapy and chemotherapy. Within these malignant gliomas, glioblastoma stem cells or initiating cells have been recently described, and they were shown to be specifically involved in experimental tumorigenesis. In this study, we show that some human glioblastoma cells injected into the striatum of immunodeficient nude mice exhibit a tropism for the subventricular zones. There and similarily to neurogenic stem cells, these subventricular glioblastoma cells were then able to migrate toward the olfactory bulbs. Finally, the glioblastoma cells isolated from the adult mouse subventricular zones and olfactory bulbs display high tumorigenicity when secondary injected in a new mouse brain. Together, these data suggest that neurogenic zones could be a reservoir for particular cancer-initiating cells.     

Jmjd3基因RNAi慢病毒载体构建及转染BMSCs效应的实验研究

目的 构建针对SD大鼠Jmjd3基因RNAi慢病毒载体,转染大鼠骨髓间充质细胞(bone marrow stromal cells,BMSCs)后观察其对Jmjd3基因的抑制作用并筛选最有效干扰序列。方法 设计4对Jmjd3基因shRNA寡核苷酸序列,插入pGCSIL-GFP载体形成重组载体。重组载体经过测序鉴定后转染293T细胞生产病毒液,病毒液转染大鼠BMSCs,Western blot分析转染前后Jmjd3表达情况。通过计算Jmjd3灰度值/ACTIN灰度值,筛选出最有效的干扰序列。结果 测序结果证实Jmjd3基因shRNA寡核苷酸序列正确插入载体中,成功构建4个大鼠Jmjd3基因RNAi表达载体。Western blot检测显示转染后Jmjd3蛋白表达显著下调,半定量分析显示相对于未转染组,shRNA-1组、shRNA-2组、shRNA-3组、shRNA-4组分别下调79.5%(P<0.001)、90.7%(P<0.001)、73.7%(P<0.001)、56.5%(P<0.001),而GFP组下调11.5%(P>0.05),shRNA-2组为最佳干扰序列。结论 针对大鼠Jmjd3基因RNAi慢病毒载体构建成功,并能有效抑制BMSCs中Jmjd3基因的表达。     

LSD1在妇科恶性肿瘤中的研究进展

组蛋白赖氨酸特异性去甲基化酶1（lysine specific demethylase 1,LSD1）是一种核内黄素腺嘌呤二核苷酸（flavin adenine dinucleotide,FAD）依赖的单胺氧化酶,不但可以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）、第9位赖氨酸（H3K9）和非组蛋白位点上的甲基基团,而且可以使非组蛋白底物第370位赖氨酸二甲基化（K370Me2）去甲基化,从而通过抑制p53与p53结合蛋白1（53BP1）的相互作用来抑制p53的功能。近年来许多研究发现,LSD1在染色质调节中起重要作用,可以通过调节肿瘤细胞的增殖、侵袭和转移能力,影响多种恶性肿瘤的发生及发展。LSD1的特殊作用使其有望成为一个新的抗肿瘤靶点。而目前LSD1表达对妇科恶性肿瘤的作用报道较为少见。本文就LSD1的结构与功能以及LSD1在宫颈癌、卵巢癌及子宫内膜癌中的最新研究进展进行综述。     

Reply: Cytotoxic effect of disulfiram/copper on human glioblastoma cell lines and ALDH-positive cancer-stem-like cells

Background:

Emerging evidence has demonstrated that lysine-specific demethylase 1 (LSD1) has an important role in many pathological processes of cancer cells, such as carcinogenesis, proliferation and metastasis. In this study, we characterised the role and molecular mechanisms of LSD1 in proliferation and metastasis of colon cancer.

Methods:

We evaluated the correlation of LSD1, CDH-1 and CDH-2 with invasiveness of colon cancer cells, and investigated the roles of LSD1 in proliferation, invasion and apoptosis of colon cancer cells. We further investigated the mechanisms of LSD1-mediated metastasis of colon cancer.

Results:

Lysine-specific demethylase 1 was upregulated in colon cancer tissues, and the high LSD1 expression was significantly associated with tumour-node-metastasis (TNM) stages and distant metastasis. Functionally, inhibition of LSD1 impaired proliferation and invasiveness, and induced apoptosis of colon cancer cells in vitro. The LSD1 physically interacted with the promoter of CDH-1 and decreased dimethyl histone H3 lysine 4 (H3K4) at this region, downregulated CDH-1 expression, and consequently contributed to colon cancer metastasis.

Conclusion:

Lysine-specific demethylase 1 downregulates the expression of CDH-1 by epigenetic modification, and consequently promotes metastasis of colon cancer cells. The LSD1 antagonists might be a useful strategy to suppress metastasis of colon cancer.     

食管鳞癌组织LSDl表达与预后相关性分析

目的：研究组蛋白赖氨酸特异性脱甲基酶1（1ysinespecificdemethylase1,LSDl）在食管鳞癌组织中的表达及其与临床病理因素的关系,并探讨其与预后的相关性。方法：收集2005—01—01—2006—12—31在福建省肿瘤医院胸外科接受食管癌三野根治术且术前未接受放疗或化疗的食管鳞癌患者135例。免疫组化检测135例食管鳞癌及其配对癌旁正常食管黏膜组织的LSDl表达水平。运用Y。检验分析肿瘤组织LSDl表达与临床病理因素的关系。运用Kaplan-Meier方法和Log—rank检验分析肿瘤组织LSDl表达与患者术后总生存时间的关系。采用Cox模型对食管癌患者预后相关因素进行多因素回归分析。结果：食管鳞癌组织LSDl强阳性表达率为53．3％,在正常食管黏膜组织中为7．6％,差异有统计学意义,x2=9．016,P=0．002。LSDl高表达与性别（x2=0．396,P=0．546）、年龄（x2=2．530,P=0．123）、T分期（x2=1．264,P=0．286）、淋巴结转移（x2=1．136,P=0．343）、TNM分期（x2=0．396,P=0．546）和分化（x2=0．415,P=0．537）无显著相关性,而与生存时间是否超过5年（x2=6．699,P=0．013）显著相关。Cox多因素回归分析显示,淋巴结转移（p=0．001）、肿瘤浸润深度（P=0．004）和LSDl表达水平（P=0．020）是食管鳞癌患者的独立预后因素。生存分析提示,LSDl强阳性组患者预后明显差于LSDl弱阳性组患者,P=0．008。亚组分析显示,在有淋巴结转移的患者中,肿瘤LSDl强阳性与患者预后相关,P=0．014;而在无淋巴结转移的患者中,LSDl强阳性与预后无显著相关性,P=0373结诊．T-Snl在仓管鳞痛钼织申表达上调．其强阳性表达与不良预后相关。     

组蛋白赖氨酸去甲基化与基因调控

随着组蛋白赖氨酸去甲基化酶的发现,证实组蛋白赖氨酸甲基化是一个可以逆转的组蛋白表遗传修饰。赖氨酸特异性组蛋白去甲基化酶1(lysinespecificdemethylase1,LSD1)是一个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H3K4和H3K9位点上的甲基基团。JmjC蛋白JHDM1、JHDM2、JMJD23个亚家族都具有组蛋白赖氨酸去甲基化酶活性。目前证实组蛋白甲基化与去甲基化失平衡与肿瘤发生相关。组蛋白赖氨酸去甲基化酶有可能成为一个新的抗肿瘤治疗靶标。     

TGF-β1上调LSD1表达激活ERK/NF-κB p65通路促进胃癌增殖的实验研究

目的探讨转化生长因子β1(TGF-β1)上调赖氨酸特异性去甲基化酶1(LSD1)表达激活下游细胞外信号调节激酶1/2(ERK1/2)/核因子κBp65(NF-κB p65)信号通路促进胃癌细胞增殖的作用机制。方法利用外源性人重组TGF-β1作用于人胃癌细胞系MGC-803、SGC-7901、AGS和正常胃黏膜细胞系GES-1。MTT法检测各组细胞增殖活性。Western blotting法检测LSD1蛋白表达。将MGC-803细胞分为5组:空白对照组、TGF-β1组、TGF-β1+TCP(LDS1抑制剂)组、TGF-β1+SIS3(SMAD3抑制剂)组、TGF-β1+SCH772984(ERK1/2抑制剂)组。Western blotting法检测p-SMAD2、p-SMAD3、p-ERK1/2、p-p65蛋白和核p65蛋白表达。采用免疫荧光染色法检测p65在细胞核中的定位。结果TGF-β1可促进MGC-803、SGC-7901、AGS细胞的增殖活性,且上调LSD1蛋白表达,呈浓度和时间依赖性。与TGF-β1组比较,TGF-β1+TCP组MGC-803细胞LSD1蛋白表达下调,增殖抑制率降低(P<0.05)。与空白对照组比较,TGF-β1组MGC-803细胞LSD1、p-SMAD2、p-SMAD3、p-ERK1/2、p-p65和核蛋白p65蛋白表达量升高(P<0.05)。与TGF-β1组比较,TGF-β1+SIS3组LSD1蛋白表达无差异(P>0.05),TGF-β1+SCH772984组LSD1蛋白表达明显降低(P<0.05),p65蛋白核定位量也减少。结论LSD1在TGF-β1促进胃癌细胞增殖中发挥着重要作用,可能与TGF-β1上调LSD1表达与激活下游ERK/NF-κB p65信号通路,促进p65核转移有关。