透明细胞肾细胞癌组织中DNMT3B异构体表达及其整体甲基化的分析

目的检测透明细胞肾细胞癌组织中DNA甲基转移酶3B(DNA methyltransferase 3B,DNMT3B)异构体表达及其整体甲基化的变化,探讨这些变化与透明细胞肾细胞癌的关系。方法选取15例透明细胞肾细胞癌及其癌旁组织,应用Real-time PCR技术检测DNMT1、DNMT3A、DNMT3B与DNMT3B六种主要异构体的mRNA表达,应用Western blot法检验DNMT3B4蛋白表达;应用联合亚硫酸氢钠的限制性内切酶分析法(COBRA)分析重复序列Alu和LINE-1的甲基化水平。结果透明细胞肾细胞癌组织中DNMT3B4 mRNA和蛋白表达水平比癌旁组织高;重复序列Alu和LINE-1的甲基化水平在透明细胞肾细胞癌组织中比癌旁组织低。结论 DNMT3B4表达增加可能与整体甲基化降低及透明细胞肾细胞癌的发生有密切关系。     

DNMT3B基因启动子单核苷酸多态性与结直肠癌易感性的关联研究

目的通过对天津地区汉族结直肠癌（cRc）患者和正常人群中DNA甲基转移酶3B（DNMT3B）基因单核苷酸多态性（SNP）位点rsl569686基因型的检测,探讨rsl569686位点基因型与CRC易感性的关系。方法应用Sequenom MassArray飞行时间质谱系统检测89例CRC患者（观察组）及94例健康者（对照组）DNMT3B基因多态位点rsl569686的基因分型,判断其与CRC的相关性。结果DNMT3B基因多态位点rsl569686的3种基因型Iq＂、GT、GG在CRC患者中的频率分别为74．2％、24．7％、1．1％,与对照组（73．4％、23．4％、3．2％）相比,差异无统计学意义（P〉O．05）。结论天津汉族人群CRC的遗传易感性可能与DNMT3B基因rsl569686位点的SNP无关。     

Association of polymorphisms in DNMT1, DNMT3A,DNMT3B,MTHFR and MTRR genes with global DNA methylation levels and prognosis of autoimmune thyroid disease

To clarify the association between factors regulating DNA methylation and the prognosis of autoimmune thyroid diseases (AITDs), we genotyped single nucleotide polymorphisms in genes encoding DNA methyltransferase 1 (DNMT1), DNMT3A, DNMT3B, methylenetetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR), which are enzymes essential for DNA methylation. Subjects for this study included 125 patients with Hashimoto''s disease (HD), including 48 patients with severe HD and 49 patients with mild HD; 176 patients with Graves’ disease (GD), including 79 patients with intractable GD and 47 patients with GD in remission; and 83 healthy volunteers (control subjects). The DNMT1+32204GG genotype was more frequent in patients with intractable GD than in patients with GD in remission. Genomic DNA showed significantly lower levels of global methylation in individuals with the DNMT1+32204GG genotype than in those with the AA genotype. The MTRR+66AA genotype was observed to be more frequent in patients with severe HD than in those with mild HD. The DNMT1+14395A/G, DNMT3B−579G/T, MTHFR+677C/T and +1298A/C polymorphisms were not correlated with the development or prognosis of AITD. Our study indicates that the DNMT1+32204GG genotype correlates with DNA hypomethylation and with the intractability of GD, and that the MTRR+66AA genotype may correlate with the severity of HD.     

DNMT3B mutations and DNA methylation defect define two types of ICF syndrome

ICF syndrome is a rare autosomal recessive disease characterized by variable immunodeficiency, centromeric instability, and facial abnormalities. Mutations in the catalytic domain of DNMT3B, a gene encoding a de novo DNA methyltransferase, have been recognized in a subset of patients. ICF syndrome is a genetic disease directly related to a genomic methylation defect that mainly affects classical satellites 2 and 3, both components of constitutive heterochromatin. The variable incidence of DNMT3B mutations and the differential methylation defect of alpha satellites allow the identification of two types of patients, both showing an undermethylation of classical satellite DNA. This classification illustrates the specificity of the methylation process and raises questions about the genetic heterogeneity of the ICF syndrome.     

上调SMYD3对人胆管癌FRH0201细胞中DNMT3B表达及细胞增殖的影响

目的: 研究人胆管癌细胞株FRH0201中SET和MYND结构域含有蛋白3(SET and MYND domain-containing protein 3,SMYD3)过度表达对DNA甲基化转移酶3B(DNA methyltransferase 3B,DNMT3B)表达及细胞增殖能力的影响。方法: 瞬时转染SMYD3真核表达质粒后, RT-PCR检测细胞中DNMT3B mRNA水平的变化;Western blotting检测细胞中DNMT3B蛋白水平的变化;CCK-8检测细胞增殖能力的改变;流式细胞术检测细胞周期的改变。结果: 以未处理组为对照,胆管癌细胞FRH0201在转染pEGFP-C3-SMYD3质粒后,DNMT3B蛋白及mRNA表达均显著上升(P<0.01);细胞的增殖能力显著提高、细胞增殖速度加快(P<0.05);进入G₂/M期的细胞明显增多(P<0.05)。结论: 过度表达SMYD3,可引起细胞中DNMT3B的表达上调并增强细胞增殖能力。     

Single Nucleotide Polymorphism in DNMT3B Promoter and the Risk for Idiopathic Thrombocytopenic Purpura in Chinese Population

OBJECTIVE: Epigenetic changes in gene expression, including DNA methylation and histone modifications, might contribute to autoimmunity. DNA methylation is mediated by a family of DNA methyltransferases. Polymorphisms of the DNA methyltransferase 3B (DNMT3B) gene may influence DNMT3B activity on DNA methylation, thereby modulating the susceptibility to some diseases. The purpose of this study was to investigate the association between the single nucleotide polymorphism (SNP) in promoter of the DNMT3B gene and the risk for development of idiopathic thrombocytopenic purpura (ITP). METHODS: In this hospital-based case-control study, the DNMT3B SNP was genotyped in 201 patients with ITP and 136 healthy controls by polymerase chain reaction-restriction fragment length polymorphism. RESULTS: The C/C genotype was not detected in both the patients with ITP and the controls. In the controls, the frequencies of T/T and C/T genotypes and T and C alleles were 97.8%, 2.2%, 98.9%, and 1.1%, respectively. There was no significant difference in genotype and allele distribution between the patients with ITP and the controls (P = 0.745 and 0.747, respectively). No significant difference was observed in genotype and allele distribution between the two groups when stratified by the age. The similar results were shown among the four groups of patients with ITP: acute childhood, chronic childhood, acute adult, and chronic adult. CONCLUSION: This polymorphism was distributed similarly between the patients with ITP and the controls. It demonstrated that it may not be used as a stratification marker to predict the susceptibility to ITP, at least in the population of North China.     

Serum homocysteine, vitamin B12, folic acid levels and methylenetetrahydrofolate reductase (MTHFR) gene polymorphism in vitiligo

The aim of this study was to determine serum vitamin B12, folic acid and homocysteine (Hcy) levels as well as MTHFR (C677, A1298C) gene polymorphisms in patients with vitiligo, and to compare the results with healthy controls. Forty patients with vitiligo and 40 age and sex matched healthy subjects were studied. Serum vitamin B12 and folate levels were determined by enzyme-linked immunosorbent assay. Plasma Hcy levels and MTHFR polymorphisms were determined by chemiluminescence and real time PCR methods, respectively. Mean serum vitamin B12 and Hcy levels were not significantly different while folic acid levels were significantly lower in the control group. There was no significant relationship between disease activity and vitamin B12, folic acid and homocystein levels. No significant difference in C677T gene polymorphism was detected. Heterozygote A1298C gene polymorphism in the patient group was statistically higher than the control group. There was no significant relationship between MTHFR gene polymorphisms and vitamin B12, folic acid and homocysteine levels. In conclusion, vitamin B12, folate and Hcy levels are not altered in vitiligo and MTHFR gene mutations (C677T and A1298C) do not seem to create susceptibility for vitiligo.     

The 844ins68 cystathionine beta-synthase and C677T MTHFR gene polymorphism and the vaso-occlusive event risk in sickle cell disease

Introduction

Sickle cell disease (SCD) is an inflammatory condition with an increase in the adhesion of sickled erythrocytes, and it is a potential cause of vaso-occlusive episodes, an event related to clinical manifestations, morbidity and mortality. The cystathionine beta-synthase enzyme gene (CBS) and the methylenetetrahydrofolate reductase enzyme gene (MTHFR) are risk factors for thromboembolic disorders. This study evaluated the frequency of the 844ins68 CBS and C677T MTHFR gene polymorphisms and their possibility to be risk factors for vaso-occlusive crises.

Material and methods

In total 91 blood samples from SCD patients were studied by PCR-RFLP and PCR-allele-specific, for the SCD genotype confirmation and polymorphism identification.

Results

The presence of clinical manifestations related to vaso-occlusive crises were more frequent among patients with the Hb SS genotype (p = 0.007). The CBS enzyme gene was three times more frequent (p = 0.011) among patients with vaso-occlusive complications. The MTHFR gene mutation frequency showed no increased risk for vaso-occlusive crises in SCD patients (p = 0.193). The interaction between the two polymorphisms was evaluated in 12.08% of the SCD patients and doubled the vaso-occlusive disease risk (relative risk: 2.16).

Conclusions

We conclude that the presence of 844ins68 CBS and C677T MTHFR gene polymorphism was a risk factor for vaso-occlusive episodes in the SCD patients evaluated.     

Genetic and expressional alterations of CHD genes in gastric and colorectal cancers

Kim M S, Chung N G, Kang M R, Yoo N J & Lee S H
(2011) Histopathology 58 , 660–668
Genetic and expressional alterations of CHD genes in gastric and colorectal cancers Aims: Chromodomain helicase DNA‐binding protein (CHD) is a regulator of the chromatin remodelling process. The aim was to determine the CHD1, CHD2, CHD3, CHD4, CHD7, CHD8 and CHD9mutational status of mononucleotide repeats in gastric and colorectal cancers with microsatellite instability (MSI). Methods and Results: The repeats were determined in 28 gastric cancers (GCs) with high MSI (MSI‐H), 45 GCs with low MSI (MSI‐L)/stable MSI (MSS), 35 colorectal cancers (CRCs) with MSI‐H and 45 CRCs with MSI‐L/MSS by single‐strand conformation polymorphism analysis. CHD4 and CHD8 expressionwas also examined in GCs and CRCs by immunohistochemistry. CHD1, CHD2, CHD3, CHD4, CHD7, CHD8 and CHD9 mutations were found in five, 19, three, five, seven, 10 and seven cancers, respectively. They were detected in MSI‐H cancers, but not in MSI‐L/MSS cancers. Loss of CHD4 expression was observed in 56.4% of the GCs and 55.7% of the CRCs, and loss of CHD8 was observed in 35.7% of the GCs and 28.6% of the CRCs. The cancers with CHD4 and CHD8 mutations showed loss of CHD4 and CHD8 expression, respectively. Conclusions: Frameshift mutation and loss of expression of CHD genes are common in GCs and CRCs with MSI‐H.These alterations might contribute to cancer pathogenesis by deregulating CHD‐mediated chromatin remodelling.     

252例结直肠癌组织中KRAS、NRAS、BRAF、PIK3CA的基因突变分析

目的分析结直肠癌(colorectal cancer,CRC)组织中KRAS、NRAS、BRAF和PIK3CA基因的常见突变类型及其与临床病理指标的关系。方法对252例CRC石蜡包埋组织进行DNA提取,采用Sanger测序法对KRAS、NRAS、BRAF和PIK3CA基因进行检测,分析各个基因的突变率与临床病理特征的关系,并统计各个基因的突变类型。结果 252例CRC中,KRAS、BRAF、NRAS和PIK3CA突变发生率在性别、年龄、肿瘤部位、病理分期和有无淋巴结转移上差异均无统计学意义(P0.05);检测阳性突变共140例(55.5%),其中KRAS 113例(44.8%),NRAS 1例(0.4%),BRAF 19例(7.5%),PIK3CA 28例(11.1%),包括PIK3CA与KRAS、NRAS、BRAF基因发生双突变21例(8.3%);KRAS的主要突变类型包括G12A、G12C、G12D、G12R、G12S、G12V、G13D、T20M、A59T、Q61H、Q61L、Q61P;NRAS仅有1例突变为G12D;BRAF的主要突变类型为V600E、D594G、K601E;PIK3CA的主要突变类型包括E542K、E545K、Q546K、Q546P、Q546R、M1043I、H1047R。PIK3CA与KRAS、NRAS、BRAF之间会发生交叉突变,但KRAS、NRAS、BRAF三者之间基本不存在交叉突变。结论 CRC中KRAS阳性突变率居高,PIK3CA次之,BRAF、NRAS突变率最低,且PIK3CA常与KRAS、NRAS、BRAF发生交叉突变。对CRC患者行KRAS、NRAS、BRAF、PIK3CA等多基因检测,可正确指导并选择抗EGFR单抗药,从而实现真正意义上的个体化靶向治疗。     

自噬相关基因LC3、Beclin-1与凋亡相关基因p53、BCL-2在大肠癌中的表达及意义

目的检测自噬相关基因LC3、Beclin-1与凋亡相关基因p53、BCL-2在大肠癌、大肠腺瘤及正常大肠黏膜中的表达情况,探讨其与大肠癌发生、发展的相关性及意义。方法应用组织芯片技术和免疫组化SP法检测12例正常大肠黏膜、29例大肠腺瘤及115例大肠癌组织中LC3、Beclin-1、p53及BCL-2蛋白的表达水平,并结合临床病理因素进行分析。结果 LC3在大肠癌中的阳性率高于大肠腺瘤和正常大肠黏膜(P<0.01),且与大肠癌的组织学分化程度相关(P<0.05)。Beclin-1在大肠癌、大肠腺瘤组织中的表达高于正常大肠黏膜(P<0.01),但与大肠癌的组织学分化程度、Dukes分期及淋巴结转移无关(P均>0.05)。p53及BCL-2在正常大肠黏膜、大肠腺瘤及大肠癌中的表达逐渐增高(P<0.01),且与大肠癌的Dukes分期和淋巴结转移相关(P均<0.05)。经Spearman秩相关检验,Beclin-1蛋白与p53蛋白相关系数为0.224 3,成正相关表达(P<0.05)。结论在大肠癌中,自噬活性的上调与凋亡能力的下调并存;自噬相关基因LC3、Beclin-1与凋亡相关基因p53、BCL-2在大肠癌的发生、发展中起协调作用,对其联合检测有助于了解和判断大肠癌的进展程度及患者的预后情况。     

No difference in the occurrence of mismatch repair defects and APC and CTNNB1 genes mutation in a multi-racial colorectal carcinoma patient cohort

BACKGROUND AND AIMS: Colorectal cancers of different subtypes involve different pathogenic pathways like the Wnt and the mutator pathways. In this study, we screened 73 colorectal cancer cases from a multi-racial group for genetic and expression profile defects with the aim of correlating these with patients' clinicopathological characteristics. METHODS: Mutation screening of the entire coding region of APC and exon 3 of CTNNB1, loss of heterozygosity (LOH) of APC, and microsatellite instability (MSI) status were assessed for 44 patients with available paired frozen normal and tumour tissues. In addition, 29 cases with available paraffin embedded tumour blocks were screened for mutation in exon 3 of CTNNB1, the APC mutation cluster region (codon 1286-1513), and hMLH1, hMSH2, hMSH6 protein expressions by immunohistochemistry method. RESULTS: In our study, 15/73 cases showed APC mutations (20.5%), 1/73 cases had CTNNB1 mutation (1.4%), 5/32 cases had APC LOH (15.6%), and 16/70 (22.9%) cases revealed at least some form of mismatch repair (MMR) defect. Tumour grade (poor differentiation) was found to correlate significantly with right-sided tumour and mucinous histology (p = 0.01879 and 0.00320, respectively). Patients of younger age (below 45 years) more often had tumours of mucinous histology (p = 0.00014), while patients of older age (above 75 years) more often had tumours on the right side of the colon (p = 0.02448). Tumours of the mucinous histology subtype often had MMR defects (p = 0.02686). There was no difference in the occurrence of APC and CTNNB1 mutations and MMR defects found within our multi-racial colorectal cancer patient cohort. CONCLUSION: Our findings support the notion that racial factor may not be related to the occurrence of MMR defects and APC and CTNNB1 mutations in our multi-racial patient cohort.     

结直肠腺癌患者外周血CNRIP1基因启动子甲基化的临床病理学分析

目的 分析结直肠腺癌患者外周血大麻素受体互作蛋白1(cannabinoid receptor interacting protein 1,CNRIP1)基因启动子甲基化程度与临床病理学参数的相关性,探讨外周血CNRIP1基因启动子甲基化检测在结直肠腺癌早期筛查及病程评估中的价值.方法 采用定量甲基化特异性PCR技术(quantitative methylation-specific PCR,qMSP)检测结直肠腺癌患者(50例)、结直肠腺瘤患者(20例)、健康志愿者(20例)外周血CNRIP1基因启动子CpG岛甲基化程度,并通过焦磷酸测序技术确定该基因启动子甲基化位点.登记结直肠腺癌患者临床病理参数.采用Fisher检验分析CNRIP1基因启动子CpG岛甲基化与结直肠腺癌临床病理参数的相关性.结果 结直肠腺癌、结直肠腺瘤患者及健康志愿者外周血CNRIP1基因启动子CpG岛的2246位点甲基化程度分别为(85.50±8.24)％、(81.33±5.81)％、(63.66％±3.61)％(P＜0.01);结直肠腺癌CNRIP基因启动子CpG岛2246位点甲基化程度分别与肿瘤直径、原发灶浸润深度、TNM分期具有显著相关性(P＜0.01),与腺癌分化程度、淋巴结转移具有一定相关性(P＜0.05).结论 CNRIP1基因启动子CpG岛2246位点甲基化程度与结直肠腺癌病程进展相对一致,可作为结直肠腺癌早期筛查及病程评估的标志物.     

Two SNPs of ATP-binding cassette B1 gene on the risk and prognosis of colorectal cancer

We conducted a case-control study to investigate the role of ABCB1 C3435T and G2677T/A in the susceptibility and prognosis of colorectal cancer patients. A total of 316 patients with colorectal cancer and 316 controls were collected between January 2009 and January 2011. Genotyping of ABCB1 C3435T and G2677T/A was conducted by the methods of Polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). Conditional logistic regression analysis showed that subjects carrying CT and CC genotypes of ABCB1 C3435T were more frequently observed in colorectal cancer patients when compared with controls, and the adjusted ORs were 1.62 (1.05-2.52) and 2.05 (1.25-3.36), respectively. By Cox regression analysis, we found that the TT genotype of ABCB1 C3435T was significantly associated with shorter PFS and OS in patients with colorectal cancer when compared with CC genotype, with adjusted HR (95% CI) of 2.57 (1.14-6.04) and 2.54 (1.05-6.61), respectively. We found that the ABCB1 C3435T polymorphism could affect the susceptibility and clinical outcome of colorectal cancer patients.     

Microbiota-dependent activation of the myeloid calcineurin-NFAT pathway inhibits B7H3- and B7H4-dependent anti-tumor immunity in colorectal cancer

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大肠癌中Beclin1、LC3和mTOR的表达及意义

目的：探讨Beclin1、LC3和mTOR在大肠癌中的表达及意义。方法采用免疫组化EnVision法、Western blot和RT-PCR技术检测Beclin1、LC3和mTOR在大肠癌中的表达,并结合临床病理因素进行分析。结果 Beclin1、LC3和mTOR在大肠癌中的阳性率分别为90．50%、87．19%和46．28%,均明显高于癌旁组织( P<0．05),且LC3蛋白在中+低分化大肠癌中的表达(91．34%、89．58%)高于高分化大肠癌(77．61%),在有淋巴结转移组的表达(95．41%)高于无淋巴结转移组(80．45%), mTOR在有淋巴结转移组的表达(57．80%)高于无淋巴结转移组(35．33%)(P<0．05),Beclin1过表达与大肠癌分化程度和淋巴结转移均无关(P>0．05)。 LC3与Beclin1在大肠癌中表达呈正相关(rs =0．593,P<0．01),与mTOR表达呈负相关(rs =-0．165,P<0．01),Beclin1和mTOR表达之间无明显相关性(P>0．05)。 Kaplan-Meier生存分析显示,Beclin1和LC3均阳性、mTOR阴性、无淋巴结转移的大肠癌患者5年生存率高于Beclin1和LC3均阴性、mTOR阳性及有淋巴结转移的患者。多因素分析显示,LC3、mTOR和淋巴结转移是影响大肠癌预后的独立因素。 RT-PCR和Western blot检测结果显示：Beclin1、LC3和mTOR mRNA和蛋白表达水平均明显高于癌旁组织(P<0．05)。结论自噬相关基因Beclin1、LC3和mTOR的异常表达可能与大肠癌的发生、发展及预后相关;联合检测Beclin1、LC3和mTOR在大肠癌中的表达有助于评估进展程度和预后判断。     

Genetic polymorphisms and expression of NLRP3 inflammasome-related genes are associated with Philadelphia chromosome-negative myeloproliferative neoplasms

Inflammation plays a crucial role in the initiation, progression and prognosis of Philadelphia chromosome-negative myeloproliferative neoplasms (MPN), which could be clinically subdivided into polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). Nucleotide binding domain (NOD)-like receptor protein 3 (NLRP3) inflammasomes affect inflammatory diseases and carcinomas by excessive production of cytokines. To investigate a possible association of NLRP3 inflammasome signaling with MPN, we investigated the expression of selected inflammasome-related genes from bone marrow cells of 67 MPN patients as well as gene polymorphisms in NLRP3 (rs35829419), NF-κB1 (rs28362491), CARD8 (rs2043211), IL-1β (rs16944), and IL-18 (rs1946518). It showed that inflammasome-related genes (NLRP3, NF-κB1, CARD8, IL-1β, and IL-18) were highly expressed in BM cells from MPN patients and the increased expression was associated with JAK2^V617F mutation, white blood cell counts and splenomegaly. Analysis of genetic polymorphisms in 269 MPN patients and 291 healthy controls demonstrated that NF-κB1 (rs28362491) was associated with MPN and increased expression of NF-κB1, NLRP3 and IL-1β. This research provided novel biomarkers and potential targets for MPN.     

DNA甲基转移酶1、3A和3B在低氧预适应小鼠大脑中的表达简

 目的 研究DNA甲基转移酶（DNMT）1、3A和3B在低氧预适应小鼠大脑中的变化,探讨低氧预适应形成过程中DNMTs的变化与脑保护作用的关系。方法 小鼠随机分成常氧组（H0）、低氧1次组（H1）或4次（H4）后取大脑皮质组织,应用实时定量PCR 技术、免疫印迹技术和DNA甲基转移酶活性检测DNMT1、DNMT3A和DNMT3B mRNA和蛋白质及DNMT活性。结果H1组和H4组DNMT3A和DNMT3B的mRNA和蛋白质水平较H0组显著降低（p<0.05）,H4组DNMT活性较H0组降低（p<0.05）。结论DNMT3A和3B水平及DNMT活力的变化可能与低氧预适应小鼠获得脑保护的关系密切。