表观遗传学和环境因素与子宫内膜异位症

子宫内膜异位症(EMs)是一种雌激素依赖的炎性疾病,发病机制尚不清楚。越来越多的证据表明,一些基因的表观遗传学特性与EMs的发病有关。表观遗传学是指DNA序列不发生变化,但基因表达却发生了可遗传的改变,包括DNA甲基化、组蛋白共价修饰及染色质构象变化,这些改变可能会引发一系列包括肿瘤在内的病理变化。EMs异位组织中芳香化酶基因的Cp G岛序列低甲基化和(或)反式作用因子上调芳香化酶基因的表达;卵巢异位上皮及间质细胞的雌激素受体α(ERα)低表达而ERβ显著高表达;在位细胞的孕激素受体α(PRα)和PRβ均高表达;EMs异位内膜细胞的类固醇生成因子1(SF-1)启动子低甲基化而在位内膜高甲基化。此外,EMs异位组织E-钙黏蛋白(E-cadherin)基因及在位组织同源框基因A10(HOXA10)表达降低也与EMs有关;环境因素可能会影响表观遗传基因导致EMs的发生。综述表观遗传学改变和环境因素在EMs发病中的作用。     

DNA methylation changes in the placenta are associated with fetal manganese exposure

Adequate micronutrient intake, including manganese (Mn), is important for fetal development. Both Mn deficiencies and excess exposures are associated with later-life disease, and Mn accumulates in the placenta. Placental functional alterations may alter fetal programming and lifelong health, and we hypothesized that prenatal exposures to Mn may alter placental function through epigenetic mechanisms. Using Illumina's HumanMethylation450 BeadArray, DNA methylation of >485,000 CpG loci genome-wide was interrogated in 61 placental samples and Mn associations assessed genome-wide via omnibus test (p = 0.045). 713 loci were associated with Mn exposure (p < 0.0001). Five significantly differentially-methylated (p < 1.3 × 10⁻⁷) loci reside in neurodevelopmental, fetal growth and cancer-related genes. cg22284422, within the uncharacterized LOC284276 gene, was associated with birth weight; for every 10% increase in methylation, lower birth weights were observed, with an average decrease of 293.44 g. Our observations suggest a link between prenatal micronutrient levels, placental epigenetic status and birth weight, although these preliminary results require validation.     

5-Aza-CdR对人结肠癌Lovo细胞增殖凋亡及抑癌基因RUNX3表达的影响

目的:研究抑癌基因RUNX3在人结肠癌细胞中的表达情况,探讨5-氮-2′-脱氧胞苷 (5-Aza-CdR)对人结肠癌Lovo细胞增殖凋亡及 RUNX3表达的影响．方法:用特异性甲基转移酶抑制剂5-Aza-CdR 0．4,4,40μmol/L处理人结肠癌细胞株Lovo 3 d,继续常规培养5d后,采用四唑盐(MTT) 比色观察细胞经药物处理前后的生长活性．以半定量RT-PCR检测细胞处理前后抑癌基因 RUNX3 mRNA的表达,应用流式细胞仪进行细胞凋亡率的检测结果:人结肠癌细胞Lovo经处理后,与对照组比较,5-Aza-CdR 0．4,4,40 μmol/L均能明显抑制肿瘤细胞生长,随5-Aza-CdR浓度增加,细胞生长速率下降;对照组Lovo细胞未见 RUNX3 mRNA表达．经药物处理后的细胞均检出该种mRNA的重新表达,其mRNA的表达相对量分别为0．46±0．06,0．71±0．06,0．84 ±0．07,与药物存在剂量依赖性(F=168．4, P<0．01):对照组细胞凋亡率为2．92％±0．93％, 5-Aza-CdR 0．4,4,40 μmol／L处理后Lovo细胞凋亡率分别为10．95％±2．09％,17．61％± 1．51％,26．60％±1．89％,与对照组相比较均有统计学意义(P<0．01),且凋亡率与5-Aza-CdR 剂量呈正相关(F=145．7,P<0．01)．结论:在人结肠癌细胞株Lovo中,基因 RUNX3可能因过甲基化而导致转录失活, RUNX3基因重新表达能抑制细胞生长,并能诱导部分细胞凋亡．     

Normal colon tissue and colon carcinoma show no difference in heparanase promoter methylation

Introduction

Heparanase, the sole heparan sulfate degrading enzyme, has a role in cellular invasion. Accordingly, a large number of studies have demonstrated an association between heparanase expression and tumor stage and patients' prognosis. In colon carcinoma, heparanase shows increased expression in tumor compared to normal tissue and its expression correlates with the presence of metastasis. One of the regulatory mechanisms of heparanase expression is de-methylation on its promoter. In the present study we evaluated the role of heparanase promoter methylation in colon carcinoma.

Material and methods

Analysis of heparanase promoter methylation was done on 32 samples of colon carcinoma as well as 30 samples of normal colonic mucosa. DNA was extracted from FFPE tissue and subjected to bisulfite conversion. The relative fraction of methylated and unmethylated DNA was evaluated using quantitative real-time PCR.

Results

The fraction of methylated DNA was 1 ± 3.4% in the colon carcinoma group, and 2.5 ± 3.3% in the normal colon group (P = 0.11). Only one case in the normal group and one case in the tumor group showed more than 10% methylation in the heparanase promoter.

Conclusion

We did not find any significant difference in heparanase promoter methylation between colon carcinoma and normal colonic mucosa, suggesting that heparanase overexpression in colon carcinoma is mediated by other mechanisms.     

Quantitative Detection of ID4 Gene Aberrant Methylation in the Differentiation of Myelodysplastic Syndrome from Aplastic Anemia

Background:The diagnosis of myelodysplastic syndrome (MDS),especially hypoplastic MDS,and MDS with low blast counts or normal karyotype may be problematic.This study characterized ID4 gene methylation ...     

Blood-based DNA methylation of DNA repair genes in the non-homologous end-joining (NEHJ) pathway in patient with glioma

To investigate the blood-based DNA methylation of repair genes including LIG4, XRCC4, XRCC5, XRCC6 and XRCC7 that involved in non-homologous end-joining (NEHJ) DNA repair pathway in patients with glioma. Blood samples were obtained from 114 glioma patients, 96 normal controls, and 81 glioma patients after radiotherapy and chemotherapy. Blood-based DNA methylation of the five NHEJ repair genes was assayed by methylation-specific polymerase chain reaction (MSP). The DNA methylation level of XRCC5 and XRCC7 in glioma group are significantly higher than those of normal group (P<0.001). Moreover, radiotherapy treatment significantly increased methylation level of XRCC5 and XRCC7 compared to glioma group. No significant difference for the methylation of the other three genes, LIG4, XRCC4 and XRCC6 were detected among three groups. In conclusion: our findings indicate that DNA methylation modification plays an important role to regulate the gene expression of XRCC5 and XRCC7, from the results that the gene methylation level of the glioma group is higher than that of the normal group. Increased methylation of XRCC5 and XRCC7 in blood samples of glioma patients and patients with radiotherapy and chemotherapy suggests that blood-based methylation level of XRCC5 and XRCC7 could be a potential indicator for evaluating of the effect of radiotherapy and chemotherapy for glioma patient.     

胆囊癌中PTEN基因异常表达及甲基化的研究

目的 探讨胆囊癌的发生、发展及转移与PTEN 基因异常表达及其基因启动子区异常甲基化的关系。方法 选取胆囊癌标本44 例（胆囊癌组）和胆囊炎标本20 例（对照组）,通过免疫组织化学染色、Western-blot、甲基化特异性PCR法分析两组患者胆囊组织中PTEN 基因表达及启动子区甲基化差异。结果 与对照组相比,胆囊癌组中PTEN 基因表达阳性率明显下降（P＜0.01）,而启动子区甲基化阳性率显著增高（P＜0.01）;胆囊癌组中有淋巴结转移者PTEN 基因表达阳性率较无淋巴结转移者降低（P＜0.05）,而启动子区甲基化阳性率增高（P＜0.05）;胆囊癌分期增高,PTEN 基因表达阳性率降低（P＜0.05）,而启动子区甲基化阳性率增高（P＜0.05）。结论 PTEN 基因低表达是胆囊癌的发生、发展及转移的重要原因之一,其低表达与启动子区过度甲基化有关。     

Methylation status of interleukin-6 gene promoter in patients with Behçet's disease

BackgroundIL-6 mRNA expression is significantly high in many autoimmune diseases such as Behçet's disease; this is often related with more aggressive phenotypes. Nevertheless, the essential molecular process for its high expression has not been completely realized. The aim of this study was undertaken to estimate the gene copy number variation and promoter methylation to IL-6's high expression.MethodsThis study was performed on 51 patients and 61 healthy controls. Initially, DNA and RNA were extracted from all specimens. Promoter methylation levels of IL-6 were evaluated by MeDIP-qPCR technique. Also, IL-6 gene expression was measured by Real-time PCR. After that, we evaluated the relationship between gene expression and methylation, as well as their relationship with clinical specification.ResultsAs we expected, the expression level of IL-6 gene increased significantly in the patient group compared to the healthy subjects. Also, the relative promoter methylation level of the IL-6 mRNA was significantly lower in patient group compared to healthy group (p < 0.001).DiscussionWe disclosed that the promoter hypomethylation may be considered as one of the main defects for IL-6 mRNA high expression in patients with Behçet's disease.     

粪便基因甲基化分析对大肠癌的早期诊断价值

目的探讨人粪便中分泌型卷曲相关蛋白(SFRP2)及增生性息肉蛋白(HPP1)基因甲基化分析对患者大肠癌诊断的价值。方法从30例结直肠癌患者、30例结直肠腺瘤患者及30例正常对照者的粪便中分别提取DNA,采用甲基化特异性PCR(MSP)技术分析其SFRP2及HPP1基因甲基化状态。结果大肠癌、腺瘤和正常对照组的SFRP2基因甲基化阳性率分别为66.6%(20/30)、50.0%(15/30)和3.3%(1/30)。大肠癌、腺瘤和正常对照组的HPP1基因甲基化阳性率分别63.3%(19/30)、43.3%(13/30)和6.6%(2/30)。结论 SFRP2和HPP1基因甲基化是大肠癌进展过程中的早期事件。粪便SFRP2和HPP1基因甲基化分析可望成为大肠癌早期无创诊断的新途径。