Parkin基因甲基化在鼻咽癌发生发展中的作用

目的探讨Parkin基因甲基化在鼻咽癌发生发展中的作用。方法应用甲基化特异性PCR技术对5个鼻咽癌细胞株（CNE1、CNE2、TW03、HONE1、C666）和1个正常鼻咽上皮细胞株（NP69）、54例鼻咽癌组织和16例正常鼻咽上皮组织的Parkin基因启动子区甲基化状态进行检测,并分析鼻咽癌组织中Parkin基因甲基化与临床特征的关系;应用RT-PCR检测加入甲基转移酶抑制剂（5-氮-2-脱氧胞苷）后CNE1、CNE2中Parkin基因转录表达,分析去甲基化对Parkin基因转录表达的影响。结果1个正常鼻咽上皮细胞株和16例正常鼻咽上皮组织中均未检测到Parkin基因甲基化;5个鼻咽癌细胞株和54例鼻咽癌组织中Parkin基因甲基化频率分别为60.00%和62.96%;54例鼻咽癌患者中Parkin基因甲基化状态与临床因素均无关（均P＞0.05）。经过5-氮-2-脱氧胞苷处理后,Parkin基因在CNE1、CNE2中转录表达增加,分别从0提高至3.65和2.15。结论鼻咽癌中Parkin基因甲基化与转录表达密切相关,是基因表达调节的一种重要方式;可能成为鼻咽癌早期分子生物学辅助诊断的标志物和去甲基化基因治疗的靶点。     

Urinary arsenic metabolism in a Western Chinese population exposed to high-dose inorganic arsenic in drinking water: Influence of ethnicity and genetic polymorphisms

To investigate the differences in urinary arsenic metabolism patterns of individuals exposed to a high concentration of inorganic arsenic (iAs) in drinking water, an epidemiological investigation was conducted with 155 individuals living in a village where the arsenic concentration in the drinking water was 969 μg/L. Blood and urine samples were collected from 66 individuals including 51 cases with skin lesions and 15 controls without skin lesions. The results showed that monomethylated arsenic (MMA), the percentage of MMA (%MMA) and the ratio of MMA to iAs (MMA/iAs) were significantly increased in patients with skin lesions as compared to controls, while dimethylated arsenic (DMA), the percentage of DMA (%DMA) and the ratio of DMA to MMA (DMA/MMA) were significantly reduced. The percent DMA of individuals with the Ala/Asp genotype of glutathione S-transferase omega 1 (GSTO1) was significantly lower than those with Ala/Ala. The percent MMA of individuals with the A2B/A2B genotype of arsenic (+ 3 oxidation state) methyltransferase (AS3MT) was significantly lower than those with AB/A2B. The iAs and total arsenic (tAs) content in the urine of a Tibetan population were significantly higher than that of Han and Hui ethnicities, whereas MMA/iAs was significantly lower than that of Han and Hui ethnicities. Our results showed that when exposed to the same arsenic environment, different individuals exhibited different urinary arsenic metabolism patterns. Gender and ethnicity affect these differences and above polymorphisms may be effectors too.     

10-羟基喜树碱对肝癌细胞HepG2 DNA甲基化水平的调节作用研究

目的:研究10-羟基喜树碱对肝癌细胞Hep G2的DNA甲基化水平的调节作用。方法:体外培养Hep G2细胞,分为给药组(10-羟基喜树碱25μg/ml)和空白对照组,每组6个小组,每小组5个平行孔,分别于给药后24、48、72 h各组取2个小组,一组用MTT法检测Hep G2细胞的生长抑制率;另一组提取Hep G2细胞的DNA,酸水解后高效液相色谱法检测其甲基化率。结果:10-羟基喜树碱作用24、48、72 h后,Hep G2细胞的生长抑制率分别为(61.6±4.9)%、(85.7±0.7)%、(97.9±0.7)%;给药组Hep G2细胞DNA甲基化率分别为(2.81±0.34)%、(6.67±0.24)%、(6.83±0.24)%,明显高于相应的空白对照组[(1.88±0.13)%、(1.91±0.11)%、(1.98±0.18)%](P<0.05),且与作用时间呈正相关。结论:10-羟基喜树碱在抑制Hep G2细胞的生长的同时提高了细胞DNA的甲基化水平。     

Upregulation of microRNA-93-5p/microRNA-4668-5p,and promoter methylation of matrix metalloproteinase-3 and interleukin-16 genes in Turkish patients with rheumatoid arthritis

Aim of the workTo investigate promoter methylation of matrix metalloproteinase-3 (MMP-3) and interleukin-16 (IL-16) genes with the expression of miRNA-93-5p and miRNA-4668-5p which target these genes in rheumatoid arthritis (RA), respectively.Patients and methodsThe study included 49 RA patients and 38 healthy controls. Promoter methylation of MMP-3 and IL-16 was analyzed by methylation-specific PCR. The expression of miRNA-93-5p and miRNA-4668-5p were determined. Disease activity score (DAS28) was assessed.ResultsThe 49 patients (38 female, 11 male) mean age was 50.4 ± 10.5 years and disease duration of 9.1 ± 7.4 years. The mean DAS28 was 3.9 ± 1.4. The MMP-3 gene methylation frequency was significantly lower in patients (n = 37;75.5%) compared to control (n = 37;97.4%) (p = 0.004) while they were comparable for IL-16 gene (n = 46;93.9% vs n = 37;97.4%)(p = 0.45). The relative normalized expression of miRNA-93-5p and miRNA-4668-5p were significantly increased (p < 0.001) in patients (2.28 ± 3.71 and 2.47 ± 4.17-fold) compared to controls (1.12 ± 0.18 and 1.28 ± 0.53-fold) and both tended to decrease with high disease activity (r =  ? 0.104, p = 0.52; r = ?0.24, p = 0.15, respectively). There was no significant difference of miRNA-93-5p (p = 0.45), and miRNA-4668-5p (p = 0.26) expressions between patients receiving treatment and those not. A negative correlation was observed between disease activity and change in expression levels of miRNA-93-5p (r = ?0.104, p = 0.52) and miRNA-4668-5p (r = ?0.24, p = 0.15). The ROC curve analysis of target miRNAs showed the diagnostic potential of miRNA-93-5p and miRNA-4668-5p (p = 0.003 and p < 0.001 respectively).ConclusionsThe methylation status of MMP-3 promoter and expression levels of miRNA-93-5p and miRNA-4668-5p could be useful biomarkers for the pathogenesis of RA and might reflect disease activity.     

hMLH1基因高甲基化在胃癌发生、发展中的作用

基因启动子区CpG岛甲基化使许多基因失活，从而导致恶性肿瘤的发生和发展。目的：检测hMLHl基因启动子区CpG岛甲基化水平，探讨其胃癌发生、发展中的作用。方法：以甲基化特异性聚合酶链反应（MSP）检测41例胃癌、40例癌前病变和38例对照组织中hMLHl基因启动子区CpG岛甲基化状态，并分析其与胃癌患者临床病理特征的关系。结果：胃癌组织中hMLHl基因启动子区CpG岛甲基化阳性率为34．1％，显著高于癌前病变组的5．0％和对照组的0％（P〈0．05）。hMLHl基因甲基化阳性率与胃癌患者的年龄和肿瘤浸润深度有关（阳性率分别为46．4％对7．7％和55．0％对14.3％，P〈0．05），与性别、肿瘤分化程度和淋巴结转移无关（阳性率分别为34．8％对33．3％、28．0％对43．8％和38．1％对30．0％）。结论：胃癌组织中存在hMLHl基因启动子区CpG岛高甲基化，可能与胃癌的发生、发展有关．且可能在老年胃癌患者的肿瘤发生过程中起重要作用。     

Nicotinic Acid Supplementation in the Context of Alcoholic Liver Injury: Friend or Foe?

Li and colleagues (2014) in this issue report that dietary nicotinic acid (NA) supplementation ameliorates ethanol‐induced hepatic steatosis, but a deficiency does not worsen injury induced by alcohol alone. The authors further present some mechanistic insights into the protective role of NA supplementation. Results of this and other previous studies in the context of alcoholic liver injury raise one important question as to what should be an adequate dose of NA that will provide the maximum benefit to hepatic and extrahepatic tissues and with minimum adverse effects.     

Methylation status of the T-cadherin gene promotor in peripheral blood mononuclear cells is associated with HBV-related hepatocellular carcinoma progression

DNA methylation is one of the epigenetic mechanisms to regulate gene expression and frequently occurs in human cancer cells. T-cadherin (CDH13) is a new member of the cadherin superfamily and possesses multiple functions. Our study included 26 normal controls (NCs), 65 chronic hepatitis B patients (CHB), 14 liver cirrhosis patients (LC) and 157 hepatocellular carcinoma patients (HCC). We mainly focused on the mRNA expression and methylation status of CDH13 in peripheral blood mononuclear cells (PBMCs), which were detected by semi-quantitative real-time polymerase chain reaction (RT-qPCR) and methylation-specific polymerase chain reaction (MSP) respectively. The CDH13 mRNA level was lower in HCC, especially in early-stage of HCC than in NCs and CHB groups (p < 0.05). Methylation frequency of the CDH13 promoter was significantly higher in HCC patients than in the NCs and CHB groups (67.52 % vs 0.00 %, p < 0.001, 67.52 % vs 52.31 %, p < 0.05, respectively). CDH13 mRNA level was significantly and relatively lower in methylated groups than in unmethylated groups among the whole participants. The methylation level of CDH13 promoter in HCC might be influenced or partly influenced by some critical factors such as TBil, ALB and AFP (p < 0.05). As an important factor in signaling pathway regulating by CDH13 to promote carcinogenesis, JNK level was significantly higher in HCC which had a higher methylation frequency than in NCs, CHB and LC (p < 0.05). Furthermore, the combination of the methylated CDH13 level and AFP level showed a better score: AUC = 0.796 (SE = 0.031, 95 %CI 0.735–0.857; p < 0.001) in male and AUC = 0.832 (SE = 0.057, 95 %CI 0.721–0.944; p < 0.001) in female compared to AFP alone for diagnosing HCC from NCs, CHB and LC. The methylation of CDH13 promoter was an independent predictor for assessing the prognosis of HCC patients (r=-1.378 p < 0.05). In conclusion, hypermethylation of CDH13 in PBMCs was associated with the underexpression of mRNA and the high risk of HCC. The methylation status of the CDH13 promoter in PBMCs was a potential noninvasive biomarker to predict the prognosis of HCC patients.