背景:通过CpG岛甲基化的基因沉默是癌症最常见的表观遗传修饰。鉴于NIS在甲状腺癌(TC)分化中的重要作用,这项横断面研究旨在调查7个CpG岛(CpG1-7,分别包括+846、+918、+929、+947、+953、+955和+963)的DNA甲基化模式。卵泡(FTC),和多结节性甲状腺肿(MNG)。此外,我们对文献进行了系统综述,将我们的结果与有关NIS基因启动子甲基化的研究进行了比较.
方法:来自64例患者的甲状腺标本符合资格标准,由28个PTC组成,9联邦贸易委员会,和27例良性MNG病例。通过qRT-PCR检测NIS的mRNA。进行亚硫酸氢盐测序PCR(BSP)技术以评估NIS基因的启动子甲基化模式。色谱中收到测序结果,FASTA,SEQ,和pdf格式,并使用色度进行分析。对于所有检查的CpG,通过mC/(mCC)公式计算每个位置和每个样品的甲基化百分比;还计算了每个CpG位点的甲基化百分比.此外,在没有限制发表日期的情况下进行了文献检索.九项研究在删除重复项后符合资格标准,无关的文章,和评论。
结果:PTC(P=0.04)和FTC(P=0.03)患者的肿瘤组织中NISmRNA水平与匹配的非肿瘤组织相比降低。NIS启动子甲基化在PTC样品中并不常见,但在FTC中常见(P<0.05)。在第4位(+947)的甲基化水平中观察到显着差异,6th(+955),FTC和MNG组织之间NIS启动子正向链中的第7个(963个)CpG位点(分别为76.34±3.12vs40.43±8.42,P=0.004、69.63±3.03vs23.29±6.84,P=0.001和50.33±5.65vs24±6.89,P=0.030)。PTC和FTC组织中NIS的表达与甲基化状况无显著相干性。
结论:NIS启动子甲基化中的扰动可能在区分MNG和FTC组织中具有潜在的作用。缺乏独特的甲基化模式意味着其他表观遗传过程的重要性,这可能会改变NISmRNA的产生。此外,根据DNA甲基化的可逆性,预计特定靶向去甲基化药物的设计将导致新的癌症治疗策略.
BACKGROUND: Gene silence via methylation of the CpG islands is cancer\'s most common epigenetic modification. Given the highly significant role of NIS in thyroid cancer (TC) differentiation, this cross-sectional study aimed to investigate the DNA methylation pattern in seven CpG islands (CpG1-7 including +846, +918, +929, +947, +953, +955, and +963, respectively) of the NIS promoter in patients diagnosed with papillary (PTC), follicular (FTC), and multinodular goiter (MNG). Additionally, a systematic review of the literature was conducted to compare our results with studies concerning methylation of the NIS gene promoter.
METHODS: Thyroid specimens from 64 patients met the eligibility criteria, consisting of 28 PTC, 9 FTC, and 27 benign MNG cases. The mRNA of NIS was tested by qRT-PCR. The bisulfite sequencing PCR (BSP) technique was performed to evaluate the promoter methylation pattern of the NIS gene. Sequencing results were received in chromatograph, FASTA, SEQ, and pdf formats and were analyzed using Chromas. The methylation percentage at each position and for each sample was calculated by mC/(mC+C) formula for all examined CpGs; following that, the methylation percentage was also calculated at each CpG site. Besides, a literature search was conducted without restricting publication dates. Nine studies met the eligibility criteria after removing duplicates, unrelated articles, and reviews.
RESULTS: NIS mRNA levels decreased in tumoral tissues of PTC (P = 0.04) and FTC (P = 0.03) patients compared to their matched non-tumoral ones. The methylation of NIS promoter was not common in PTC samples, but it was frequent in FTC (P < 0.05). Significant differences were observed in the methylation levels in the 4th(+ 947), 6th(+ 955), and 7th(+ 963) CpGs sites in the forward strand of NIS promoter between FTC and MNG tissues (76.34 ± 3.12 vs 40.43 ± 8.42, P = 0.004, 69.63 ± 3.03 vs 23.29 ± 6.84, P = 0.001 and 50.33 ± 5.65 vs 24 ± 6.89, P = 0.030, respectively). There was no significant correlation between the expression and methylation status of NIS in PTC and FTC tissues.
CONCLUSIONS: Perturbation in NIS promoter\'s methylation individually may have a potential utility in differentiating MNG and FTC tissues. The absence of a distinct methylation pattern implies the importance of other epigenetic processes, which may alter the production of NIS mRNA. In addition, according to the reversibility of DNA methylation, it is anticipated that the design of particular targeted demethylation medicines will lead to a novel cancer therapeutic strategy.