JAM3基因甲基化是食管鳞状细胞癌潜在的分子标志物

目的研究JAM3基因启动子区在食管癌中的甲基化情况及其表达调控机制,探讨JAM3基因启动子区异常甲基化作为食管鳞状细胞癌的潜在诊断标志物和治疗靶标。方法应用半定量RT-PCR、甲基化特异性PCR等技术对7个食管癌细胞系(KYSE140、KYSE150、KYSE410、KYSE450、COLO680N、KYSE520和TE13)、5例正常食管黏膜组织和83例原发性食管鳞状细胞癌组织进行分析。结果JAM3 mRNA在KYSE520、KYSE140、KYSE450细胞中高表达,这些细胞的JAM3基因启动子区呈非甲基化状态。JAM3 mRNA在KYSE410、COLO680N、TE13、KYSE150细胞中表达缺失,且其基因启动子区在这些细胞中呈完全甲基化。经过5-Aza-dc处理后,JAM3基因在KYSE410、COLO680N、TE13、KYSE150细胞中恢复表达。这些结果表明,JAM3在食管癌细胞中的表达受启动子区甲基化的调控。JAM3基因启动子区在5例正常食管黏膜组织中呈非甲基化状态(0/5),而在原发性食管鳞状细胞癌中其甲基化率为50.6%(42/83),且JAM3甲基化与肿瘤的位置相关(P<0.05)。结论JAM3在食管鳞状细胞癌中频繁发生甲基化,JAM3基因的表达受启动子区甲基化的调控,JAM3基因是潜在的食管癌诊断标志物和治疗靶标。     

Expression of OCT4 in human esophageal squamous cell carcinoma is significantly associated with poorer prognosis

AIM: To explore the expression pattern of OCT4 in human esophageal squamous cell carcinoma and its significance in diagnosis and prognosis.METHODS: Using real-time polymerase chain reaction (PCR), Western blotting, immunocytochemistry and immunohistochemistry, the expression of OCT4 in three esophageal squamous cancer cell lines, KYSE70, KYSE140 and KYSE450, was characterized. OCT4 expression was investigated in a series of 153 esophageal squamous cell carcinoma samples using immunohistochemistry and explored its association with clinicopathological features.RESULTS: Immunohistochemically, OCT4 positive immunostaining was observed in cancer cell nuclei. OCT4 was variably expressed in three esophageal squamous cancer cell lines. Among 153 specimens, 105 (68.7%) were negative or weakly positive for OCT4 staining; 21 (13.7%) were moderately positive and 27 (17.6%) were strongly positive. Higher expression level of OCT4 was significantly associated with higher histological grade (P < 0.001) and poor clinic outcome (P < 0.001).CONCLUSION: The expression of OCT4 enables the tumor to have a higher degree of stemness, which in turn results in a poorer clinical outcome for patients with esophageal squamous cell carcinoma.     

p16 inactivation by methylation of the CDKN2A promoter occurs early during neoplastic progression in Barrett's esophagus

BACKGROUND & AIMS: The potential role of p16 inactivation by CDKN2A/p16 promoter hypermethylation and/or loss of heterozygosity (LOH) of the CDKN2A gene was investigated in neoplastic progression of Barrett's esophagus. METHODS: CDKN2A promoter hypermethylation was studied by methylation sensitive single-strand conformation analysis and sequencing using bisulfite modified DNA in Barrett's esophageal adenocarcinomas, premalignant lesions, and normal squamous esophageal epithelium. All of the lesions of interest were sampled by microdissection from paraffin-embedded fixed tissue sections. RESULTS: No methylation of the CDKN2A promoter was found in normal esophageal squamous cell epithelia, whereas methylation was detected in 18 of 22 (82%) adenocarcinomas and 10 of 33 (30%) premalignant lesions, including 4 of 12 (33%) samples with intestinal metaplasia only. LOH at the CDKN2A gene locus was found in 68% of adenocarcinomas and in 55% of premalignant lesions. Of 28 samples without p16 immunoreactivity, 25 (89%) showed CDKN2A promoter hypermethylation with or without LOH of CDKN2A. Only 2 (8%) samples expressing p16 protein were found to be methylated; these showed a mixture of completely methylated and unmethylated CDKN2A promoters. In 7 of 19 (37%) informative samples without LOH of CDKN2A, the CDKN2A promoter was found to be methylated at both alleles. Loss of p16 protein expression was strongly associated with CDKN2A promoter hypermethylation (P < 0.00001), but not with LOH (P = 0.33). CONCLUSIONS: Our results indicate that methylation of the CDKN2A promoter is the predominant mechanism for p16 inactivation. This hypermethylation is a very common event in esophageal adenocarcinoma and occurs as early as metaplasia.     

Aristaless-like homeobox-4 gene methylation is a potential marker for colorectal adenocarcinomas

BACKGROUND & AIMS: The identification of novel genetic and epigenetic markers indicative of changes in the pathogenesis of colon cancer, along with easier-to-use, more sensitive assay methods, may improve the detection, treatment, and overall prognosis of this malignancy. METHODS: Using methylation-specific arbitrarily primed polymerase chain reaction, a fragment of the Aristaless-like homeobox-4 (ALX4) gene that was highly methylated in colon adenomas and cancer was identified. Methylation of ALX4 was analyzed in colorectal adenomas and cancers, in the liver metastases of patients with colorectal cancer, and in 61 other neoplasias, including gastric, esophageal, and hepatocellular cancer and cholangiocarcinoma. ALX4 methylation was also analyzed in the serum of 30 patients with colon cancer. RESULTS: ALX4 gene methylation was confirmed in colon adenomas (11/13) and more frequently present in primary colorectal cancers (30/47) compared with the normal colon mucosa (0/21) (P < .0001). In addition, ALX4 methylation was frequently observed in adenocarcinomas of the esophagus (12/14), stomach (11/15), and bile ducts (4/5) compared with all other cancers (P < .001). ALX4 gene methylation was also more frequently found in sera of patients with colon cancer compared with noncancer controls (P < .0001). Using a cutoff of 41.4 pg/mL, sensitivity and specificity were 83.3% and 70%, respectively. CONCLUSIONS: Apart from colon adenomas and primary and metastatic colorectal cancers, ALX4 is frequently methylated in adenocarcinomas of the gastrointestinal tract. ALX4 gene methylation in sera of patients with cancer may thus serve as a methylation-specific test for colon and other gastrointestinal cancers.     

CHD5基因在食管癌中的表观遗传学改变

目的:研究食管癌发病过程中染色质解旋酶DNA结合蛋白5(Chromodomain helicase DNA-binding protein5,CHD5)基因表观遗传学改变,探讨CHD5基因甲基化作为食管癌诊断标志物的可行性.方法:用甲基化特异性聚合酶链反应(methylation specific PCR,MSP)检测72例食管癌组织及成对癌旁组织,9例正常食管黏膜组织及4株食管癌细胞系中CHD5基因的甲基化状态,并用逆转录聚合酶链式反应(RT-PCR)检测CHD5基因在上述食管癌细胞系的表达.结果:69%(50/72)食管癌组织发生CHD5基因启动子区甲基化,32%(23/72)癌旁组织发生甲基化,差异具有统计学意义(χ2=20.254,P<0.05).9例食管正常组织未发生甲基化,2株食管癌细胞系中由于基因启动子区甲基化导致CHD5基因表达缺失,经5-aza-deoxycytidine处理96h后CHD5重新表达.结论:食管癌中CHD5基因频繁发生甲基化,表观遗传学改变是其基因表达的重要调节机制,CHD5基因甲基化有可能作为食管癌诊断的标志物.     

粪便DNA中MGMT、XAF1基因启动子甲基化联合检测在结直肠癌筛查中的应用研究

目的使用甲基化特异性PCR(MSP)方法检测粪便DNA中O6-甲基鸟嘌呤-DNA甲基转移酶(MGMT)、X染色体连锁凋亡抑制蛋白相关因子1(XAF1)基因启动子甲基化情况,并探讨其在结直肠肿瘤诊断中的意义。方法收集40例结直肠腺癌、40例腺瘤性息肉、52例正常对照住院患者粪便标本,使用试剂盒提取其粪便中肠道脱离细胞DNA,通过MSP方法检测其MGMT、XAF1基因启动子甲基化情况。结果 MGMT、XAF1基因启动子甲基化在结直肠腺癌中的阳性率分别为50.0%、55.9%;在腺瘤性息肉中的阳性率分别为42.1%、52.6%;二者联合检测在结直肠腺癌及腺瘤性息肉中的阳性率分别为73.5%、68.4%;特异性为52.0%。结直肠腺癌患者粪便中粪便潜血阳性率为35.3%,CEA阳性率为35.3%。结论通过试剂盒提取粪便DNA具有较高成功率;粪便DNA中MGMT、XAF1基因启动子甲基化状态用于检测结直肠腺癌及腺瘤性息肉具有较高的敏感性。检测粪便基因甲基化有望成为CRC高风险人群筛查的一个重要途径。     

The methylation status of the TMS1/ASC gene in cholangiocarcinoma and its clinical significance

BACKGROUND: TMS1/ASC is a bipartite protein comprising two protein-protein interactive domains: pyrin (PYD) and caspase recruitment domain (CARD). Proteins containing these domains play pivotal roles in regulating apoptosis and immune response pathways. The absence of TMS1/ ASC expression in some tumors is because methylation of the TMS1/ASC gene contributes to carcinogenesis and cancer development. We studied the methylation status of the TMS1/ASC gene and its clinical significance in cholangiocarcinoma. METHODS: Target DNA was modified by sodium bisulfite, coverting all unmethylated, but not methylated, cytosines to uracil, and subsequently by a nested amplification with primers specific for methylated versus unmethylated DNA. The PCR product was detected by gel electrophoresis and combined with the clinical records of patients. RESULTS: Aberrant methylation of the TMS1/ASC gene was detected in specimens of colorectal cancer tissues from 13 (36.1%) of 36 patients, and specimens of adjacent normal tissues from 3 patients (8.3%). No statistical differences were seen in the extent of differentiation and invasion, lymph node metastasis, and pathologic type between the methylated and unmethylated tissues (P>0.05). CONCLUSIONS: The frequency of TMS1/ASC gene methylation in cholangiocarcinoma is high, but it is not related to pathologic changes. The TMS1/ASC gene is probably suppressed by methylation, and is resistant to apoptosis and immunological surveillance. The gene epigenetically affected in methylated tissues could be associated with carcinogenesis of cholangiocarcinoma.     

cystatin B基因在人食管癌中的表达

目的：研究cystatinB基因在人食管癌中的表达状况。方法：采用逆转录聚合酶链反应（RT－PCR）方法检测41对食管癌组织及配对食管癌旁黏膜和食管癌细胞系EC9706和肺癌细胞系GLC82中cystatinB基因的表达。结果：cystatinB基因在82．95（34／41例）食管癌组织中的表达水平,低于配对的食管癌旁黏膜,且与食管癌淋巴结转移显著相关（P＜0．05）。在食中细胞系EC9706有微弱表达,在肺癌细胞系GLC82未检测到表达。结论：cystatinB基因在人食管癌中表达显著下调且与淋巴结转移相关。     

长链非编码RNA-lncRNA2在食管癌中高表达

目的探讨lncRNA2在食管癌中的表达情况,及lncRNA2异常表达作为食管癌的潜在诊断标志物和治疗靶标的可能。方法应用lncRNA表达芯片技术对14对配对的食管癌和癌旁组织进行分析,获得在癌组织和癌旁组织中差异表达>10倍的lncRNA 134个。应用RT-PCR技术在食管癌细胞系进行验证,并分析43对配对的癌及癌旁组织中的表达情况。结果在14个食管癌细胞系中,lncRNA2在10个食管癌细胞系中高表达,而在4个食管癌细胞系中缺失表达。在43对配对的食管癌及癌旁组织中,lncRNA2在26例癌组织中高表达,在癌旁组织中缺失表达或低表达;11例在癌组织中缺失表达或低表达,而在癌旁组织中高表达;另外6例在癌组织和癌旁组织中均缺失表达。lncRNA2在60.47%(26/43)的食管癌组织中高表达,而在25.58%(11/43)的癌旁组织中高表达,差异有统计学意义(P<0.01)。lncRNA2高表达与患者年龄、性别、TNM分期、肿瘤大小、吸烟史、饮酒史、家族史等临床因素无相关性(P均>0.05)。结论lncRNA2在食管癌中表达明显升高,是食管癌潜在的诊断标志物和治疗靶标。     

肝素酶基因表达与食管癌转移的关系

目的　探讨肝素酶基因表达与食管癌转移的关系。方法　采用逆转录聚合酶链反应技术 ( RT-PCR)检测 5 4例食管癌组织、癌旁组织及正常粘膜中肝素酶基因的表达。结果　有淋巴结转移的食管癌癌组织中肝素酶基因阳性表达率为 90 .5 % ( 19/ 2 1) ,癌旁组织为 6 1.9% ( 13/ 2 1) ,正常粘膜为 0 ( 0 / 2 1)。无淋巴结转移的食管癌癌组织中肝素酶基因阳性表达率为 15 .2 % ( 5 / 33) ,癌旁组织为 6 % ( 2 / 33) ,正常粘膜为 0 ( 0 / 33)。有淋巴结转移的食管癌组织及癌旁组织中肝素酶基因阳性表达率均高于无淋巴结转移者 ,二者相比差异均有显著性 (癌组织 P<0 .0 0 1,癌旁组织 P<0 .0 5 )。结论　肝素酶基因表达可能与食管癌发生转移有关 ,其可能成为预测食管癌转移的指标     

特异性PCR法检测胰腺癌p16基因甲基化改变

目的：探讨胰腺癌p16基因启动子区5'CpG岛甲基化改变的特点及其与临床病理特征的关系。方法：应用甲基化特异性PCR法进行甲基化检测。结果：14／36例胰腺癌标本的p16基因启动子区5'CpG岛检测到甲基化，甲基化频率为38．9％，5例癌旁组织、1例正常胰腺组织、7例慢性胰腺炎及2例胰腺粘液性囊腺瘤未发现相应区域的甲基化。结论：p16基因启动子区5'CpG岛甲基化是胰腺癌p16基因失活的机制之一，是胰腺癌细胞区别与正常细胞的分子事件。检则p16基因甲基化可能有助于胰腺癌的诊断及鉴别诊断。