TIMP-3在肝癌组织中的表达及其与肿瘤侵袭转移的关系

目的: 检测金属蛋白酶-3组织抑制剂(TIMP-3)在肝细胞癌患者血浆和肿瘤及正常肝组织中的表达并探讨其临床意义。方法: 收集56例肝细胞癌患者和30例对照组的血浆,从肿瘤大小、分化程度、肝外转移、门脉转移及淋巴转移几个因素比较TIMP-3蛋白表达水平;取手术标本包括30例原位癌组织标本、30例门脉癌栓组织标本、30例淋巴转移组织标本以及30例肝正常组织标本,采用RT-PCR和Western blotting法检测各个样本的TIMP-3mRNA及蛋白表达,结合临床病理资料分析其意义。结果: (1)有肝外转移患者的血浆TIMP-3蛋白表达水平明显低于无肝外转移者(P<0.05)。(2)TIMP-3 mRNA在原位肝癌组织中表达水平为0.52±0.09,在门脉癌栓组织中的表达水平为0.42±0.07,在淋巴转移灶的表达水平为0.40±0.08,在正常肝组织中表达水平为0.78±0.09;3组肿瘤组织与正常肝组织相比,TIMP-3 mRNA表达均降低,显著差异(P＜0.01)。(3)TIMP-3蛋白在原位肝癌组织中表达水平为77.04±8.83,在门脉癌栓组织中的表达水平为64.43±3.80,在淋巴转移灶的表达水平为62.80±3.73,在正常肝组织中表达水平为115.08±8.60;3组肿瘤组织与正常肝组织相比TIMP-3蛋白表达均降低,显著差异(P＜0.01)。结论: 肝癌患者血浆和组织中TIMP-3的表达水平明显下降,在转移灶中的表达下降更显著,提示TIMP-3的低表达与肿瘤细胞的侵袭转移能力有关。     

骨巨细胞瘤TIMP-3启动子甲基化的研究

目的 检测骨巨细胞瘤(GCT)中TIMP—3启动子甲基化及其蛋白表达，探讨该肿瘤组织TIMP—3蛋白表达缺失的原因和TIMP-3启动子甲基化与GCT分级和复发的关系。方法 用免疫组织化学SP法和蛋白免疫印迹检测TIMP—3在GCT组织中的表达，用甲基化特异的PCR(MSP)法检测TIMP—3基因启动子的甲基化状态。结果 TIMP—3主要在单核基质细胞和多核巨细胞的胞质表达，后者的表达具有明显的极向性。17例GCT中有5例(29．4％)TIMP—3蛋白丢失，其中4例的TIMP—3启动子发生异常甲基化，且均为组织学分级为Ⅱ级的病例。结论 GCT的局部骨质破坏，可能与TIMP—3丢失有关；而TIMP—3启动子的异常甲基化，是TIMP—3基因失活和蛋白丢失的重要机制。     

肝细胞癌中ZHX2基因启动子甲基化增强AFP的表达

目的探讨肝细胞癌中锌指和同源框2(ZHX2)基因启动子甲基化表达与血清AFP水平的关系,分析AFP基因的表达调控机制。方法以0.5、1.0及5.0μmol/L甲基化抑制剂5-氮杂脱氧胞苷(5-Aza-Dc)培养人肝癌细胞株HepG2,采用RT-PCR及Western blot法检测用药前后ZHX2及AFP基因的mRNA和蛋白表达差异。运用甲基化特异性PCR检测肝细胞癌组织38例中ZHX2基因启动子表达情况,分析其与血清AFP水平的关系。结果 HepG2可见少量ZHX2 mRNA扩增,未检测到ZHX2蛋白表达,而AFP却高表达;应用终浓度为1.0μmol/L和5.0μmol/L的5-Aza-Dc处理肝癌细胞6 d,ZHX2表达明显增加,而AFP却表达下调。血清AFP高于25 ng/mL肝细胞癌组织中ZHX2启动子甲基化51.6%,明显高于血清AFP小于25 ng/mL组(P<0.05)。结论 ZHX2基因启动子甲基化与AFP基因的表达有关。     

DNA错配修复基因甲基化在肝细胞癌发生发展中的作用

目的探讨DNA错配修复基因(MMR)hMLH1,hMSH2和hMSH3甲基化在肝细胞癌(HCC)发生发展中的作用。方法采用甲基化特异性聚合酶链反应(MSP)法对38例新鲜HCC组织,相应非肿瘤肝组织,2例正常的捐肝组织及6种肝癌细胞系的hMLH1,hMSH2和hMSH3基因启动子CpG岛甲基化进行检测;培养6种肝癌细胞系,MSP法检测加入5-aza-2‘-deoxycytidine前后hMSH2基因在HCC中的甲基化状态改变;逆转录．聚合酶链反应(RT-PCR)方法检测加入5-aza-2’-deoxycytidine前后hMSH2在肝癌细胞株中的mRNA表达改变。结果HCC标本中13．2％(5／38)发生了hMLH1启动子甲基化,68．4％(26／38)发生了hMSH2启动子甲基化;相应的非肿瘤肝组织中hMLH1,hMSH2启动子甲基化阳性率分别为2．6％(1／38),55．3％(21／38);2例正常肝组织中未发现甲基化;6株肝癌细胞系中有5株发生了hMSH2启动子甲基化,而未发现有MLH1启动子甲基化。所有标本中均未发现有hMSH3启动子甲基化。5-aza-2‘-deoxycytidine处理细胞株后,可部分或完全逆转hMSH2启动子甲基化,各细胞株的mRNA均有不同程度的表达增加。结论hMSH3基因启动子CpG岛甲基化与HCC的发生发展关系不大。hMSH2基因甲基化与mRNA表达密切相关,是基因表达调节的一种重要方式。hMLH1和hMSH2基因启动子CpG岛的高甲基化在HCC中是一个常见的基因改变,DNA错配修复基因尤其是hMSH2基因启动子甲基化在HCC的发生中起了重要作用,是早期事件,其可能为临床诊断HCC提供新的检测指标。     

Hedgehog通路下游转录因子Gli1在肝细胞癌中的表达及其临床意义

目的:探讨hedgehog信号通路下游转录因子Gli1在肝细胞癌中的表达及临床意义。方法:收集63例肝细胞癌组织及相对应的癌旁组织构建成组织芯片,应用免疫组化、RT-PCR法检测Gli1在肝细胞癌及癌旁组织中的表达情况。结果:Gli1蛋白在肝癌组织与癌旁组织中表达具有显著性差异;Gli1mRNA含量在肝癌组织及癌旁组织中具有显著性差异;肝细胞癌中Gli1蛋白表达和mRNA含量与病理分级、门脉癌栓有无、淋巴结转移与否、原发肿瘤分级、TNM分期密切相关。结论:Gli1的上调参与了肝细胞癌的发生发展,与肿瘤转移侵润有关。Gli1可能成为肝细胞癌重要生物学标志和生物治疗靶点。     

TIMP-3基因甲基化与结直肠癌临床病理的关系

目的：探讨TIMP-3基因甲基化与结直肠癌临床病理指标和转移复发的关系。 方法： 采用巢式甲基化特异性PCR技术（nMSP法）检测100例结直肠癌组织和100例癌旁非癌组织TIMP-3基因甲基化；采用RT-PCR检测100例结直肠癌组织和100例癌旁非癌组织TIMP-3 mRNA的表达。 结果： 肿瘤组织TIMP-3 mRNA的表达阳性率为64%，肿瘤组织TIMP-3 mRNA的表达率明显低于癌旁非癌组织（P＜0.01）；TIMP-3 mRNA的表达率无淋巴结转移组（34/42）高于淋巴结转移组（30/58）（P＜0.01），甲基化阳性率Duke’s C+D期伴淋巴结转移组明显高于Duke’s A+B期不伴淋巴结转移组（P＜0.05）。结肠近端、分化程度差的结直肠癌组织甲基化阳性率明显高于远端直肠和分化程度高者（P＜0.05）。 结论： TIMP-3基因甲基化容易发生在结肠近端、Duke’s C、D期、伴淋巴结转移、细胞分化差和浸润型结直肠癌患者。     

5Aza-dc对癌细胞TIMP-3启动子去甲基化的作用

目的：观察5-氮杂-2'-脱氧胞苷（5-Aza-2'-deoxycytidine，5Aza-dc）对癌细胞TIMP-3启动子甲基化的影响。 方法： 用5Aza-dc处理TIMP-3启动子甲基化的H2M肝癌细胞和A431表皮癌细胞，用Transwell检测癌细胞的侵袭及运动能力，用Western blot 检测TIMP-3的蛋白表达，用RT-PCR检测TIMP-3 mRNA的表达，用甲基化特异性PCR检测TIMP-3基因启动子的甲基化。 结果： （1）5Aza-dc作用后的H2M和A431细胞的侵袭及运动能力降低；（2）5Aza-dc作用后的H2M和A431细胞的TIMP-3蛋白及mRNA表达量增加；（3）5Aza-dc作用后的H2M和A431细胞的TIMP-3启动子区未检测到甲基化。 结论： 5Aza-dc可以使肝癌和表皮癌细胞TIMP-3启动子区去甲基化，使TIMP-3得以重新表达，恢复其抑制肿瘤侵袭和移动的能力。     

肝癌患者组织中凝血及纤溶因子的基因表达检测与分析

目的:检测组织因子（TF）、尿激酶型纤溶酶原激活物（uPA）及其受体（uPAR ）mRNA在肝细胞癌组织中的表达并探讨其临床意义。 方法:利用RT-PCR法分别检测27例肝细胞癌、癌旁及27例正常肝组织中TF、uPA、uPA mRNA表达阳性率及相对表达强度，并结合临床病理资料进行分析。 结果:TF、uPA、uPAR在肝细胞癌组织中阳性率及相对表达强度分别为62.96%（17/27）、70.37%（19/27）、77.78%（21/27）；0.567±0.268、0.964±0.458、0.784±0.322,均显著高于癌旁组织及正常组织，差异显著(P<0.05)。3者在肝癌组织中相对表达强度与肿瘤大小及部分侵袭转移指标有关，其中TF mRNA表达强度在肝内及肝外转移及门脉癌栓组高于无肝内及肝外转移及无门脉癌栓组(P<0.05) ，uPA mRNA在有包膜侵润、肝内转移及门脉癌栓组高于无包膜侵润、无肝内转移及门脉癌栓组(P<0.05)；uPAR mRNA在有肝内转移及门脉癌栓组高于无肝内转移及门脉癌栓组(P<0.05)。经Pearson检验肝细胞癌患者TF、uPA和uPAR mRNA表达呈正相关［TF-uPA：r=0.373(P<0.01)，TF-uPAR：r=0.534(P<0.01)，uPA-uPAR：r=0.365 (P<0.01)］。 结论:肝细胞癌组织中TF、uPA及uPAR的mRNA显著升高并与部分侵袭转移指标有关，提示3者可能在肝细胞癌的发生及侵袭转移起协同作用。     

MMP-2,TIMP-1在肝细胞癌中的表达及临床意义

目的:探讨基质金属蛋白酶-2(MMP-2)及抑制剂-1(TIMP-1)在人肝癌及癌旁组织中的表达及其与肝癌侵袭转移的关系.方法:应用免疫组织化学法研究50例肝癌及癌旁组织中MMP-2和TIMP-1的表达.结果:MMP-2在肝癌和癌旁组织表达阳性率分别为76%和72%,明显高于正常肝组织的表达(P<0.01)a TIMP-1在肝癌组织和癌旁组织中的表达阳性率分别为58%和56%,高于正常肝组织中的表达(P<0.01).而MMP-2洋相表达率与肝细胞癌的转移、淋巴浸润、包膜形成和肿瘤分化有关(P<0.05).而TIMP-1的表达与癌组织的转移,淋巴结浸润和包膜形成有关(P<0.05).结论:MMP-2,TIMP-1在肝癌及癌旁组织中的表达明显增高,可能对于判断肝癌的浸润、转移有重要价值.     

肾细胞癌RASSF1A基因启动子区甲基化状况与表达水平研究

目的检测19例肾细胞癌患者癌组织及癌旁组织Ras相关区域家族蛋白1A（RASSFlA）基因启动子区甲基化情况并检测其mRNA表达水平，探索两者之间的联系。方法收集肾细胞癌患者癌组织及相应癌旁组织19份，分别提取其基因组DNA，以甲基化特异性PCR（Methylation special PCR，MSP）法检测RASSFlA基因启动子区甲基化情况。并以QPCR法检测了RASSFlA基因的mRNA表达水平。结果19例中有lO例肾细胞癌患者癌组织存在高甲基化，mRNA表达水平表达降低，二者之间存在显著负相关性（r=-0．8734，P〈0．01）。结论肾细胞癌中RASSFlA基因启动子区存在高甲基化，并抑制该基因的表达。     

Silencing of PCDH10 in hepatocellular carcinoma via de novo DNA methylation independent of HBV infection or HBX expression

PCDH10 is a key tumor suppressive gene for nasopharyngeal, esophageal, and other carcinomas with frequent methylation. In this study, we investigated the potential epigenetic modification of the PCDH10 gene by hepatitis B virus × protein (HBx), a pivotal factor in the progression of HBV replication and potential carcinogenesis. PCDH10 expression was found to be down-regulated in 9/13 (69.2 %) of hepatocellular carcinoma (HCC) cell lines. Decreased PCDH10 expression was correlated with the methylation status of the PCDH10 promoter. Treatment with the DNA methyltransferase inhibitor 5-aza-2′-deoxycytidine (Aza) was sufficient to restore PCDH10 mRNA expression by suppressing PCDH10 promoter methylation in HepG2 cells. Treatment with Trichostatin A alone had no significant effect on PCDH10 expression but enhanced the effect of Aza. PCDH10 methylation was further detected in 76 % (38 of 50) of HCC tissues compared with 40 % (20 of 50) of paired adjacent tissues, with no methylation detected in normal human liver tissues. There were significant correlations between methylation status of PCDH10 and tumor size, serum AFP levels, metastasis or TNM staging (P < 0.05). Moreover, PCDH10 promoter methylation status was not associated with HBV infection in our panel of 50 primary HCC tumors, and transfection with HBX could not alter the status of PCDH10 promoter methylation. Collectively, these observations suggested that the expression of PCDH10 was silenced in HCC via de novo DNA methylation independent of HBV infection or HBX expression, and PCDH10 might form a potentially useful therapeutic target for HCC.     

Detection of promoter methylation status of suppressor of cytokine signaling 3 (SOCS3) in tissue and plasma from Chinese patients with different hepatic diseases

SOCS3 as an important negative regulator of IL6/JAK/STAT3 signaling pathway may be early critical determinants of carcinogenesis. This study aimed to explore the aberrant promoter methylation of SOCS3 gene in circulating DNA as a noninvasive biomarker for screening hepatocellular carcinoma (HCC) high-risk individuals and for prognosis of HCC patients after partial hepatectomy. We detected its methylation status in 116 liver tissues and 326 plasma specimens of different hepatic diseases and healthy subjects, and its mRNA and protein expression in tissues. Higher methylation rate was remarkably detected in HCC (47.92%), compared with corresponding non-tumor (25.0%), liver cirrhosis (LC) (10.0%), benign liver diseases (0%) and normal liver tissues (0%) (all P < 0.05). SOCS3 mRNA level was significantly lower in methylated HCC tissues (P < 0.05). The expressions of SOCS3 and pSTAT3 were affected by methylation status. Correlation and consistency of SOCS3 methylation were found between cancer tissue and corresponding plasma (P < 0.001, κ = 0.747). The detection rate of plasma for HCC reached 73.91%, with no false positive error. SOCS3 methylation status both in tissue and plasma was significantly associated with AFP400, tumor size, tumor differentiation, LC, metastasis and recurrence (all P < 0.05). Patients with SOCS3 methylation were followed up a markedly poorer prognosis than those unmethylated for disease-free survival (P < 0.05). These data indicate that methylation status of SOCS3 in plasma cell-free DNA can correctly reflect that in tissue DNA and be used as a noninvasive potential biomarker for chronic liver disease monitoring, predicting the degree of malignancy and poor prognosis of HCC.     

Involvement of adenomatous polyposis coli (APC) gene in testicular yolk sac tumor of infants

The pathogenesis of testicular yolk sac tumor (YST) of infants is still unclear. Infantile YSTs rarely show isochromosome 12p or aneuploidy, which are common in adult germ cell tumors. On the other hand, recent epigenetic studies suggest the involvement of some tumor suppressor genes, including the adenomatous polyposis coli (APC) gene. In the present study, we examined 10 infantile pure YSTs for mutation, allelic loss, promoter methylation, and protein expression status of the APC gene to evaluate whether the APC gene plays a significant role in the pathogenesis of infantile YSTs. Loss of heterozygosity at 5q21, where the APC gene is localized, was detected in at least 3 (30%) of the 9 YSTs examined. None of the 10 YSTs showed mutations. Promoter methylation was detected in 7 (70%) of the 10 YSTs; among 7 YSTs showing methylation, 3 YSTs also harbored loss of heterozygosity at 5q21. Immunohistochemically, 8 infantile YSTs did not express the APC protein, whereas 2 YSTs without showing APC methylation, as well as germ cells of normal infantile testes, expressed this protein in the cytoplasm. These data indicate that inactivation of the APC gene, by allelic loss and/or promoter methylation, is related to the occurrence of infantile YSTs.     

EXTL3 promoter methylation down-regulates EXTL3 and heparan sulphate expression in mucinous colorectal cancers

Exostoses like-3 (EXTL3) is a putative tumour suppressor gene but its involvement in colorectal cancer (CRC) is unclear. We have investigated the role of methylation of the EXTL3 promoter as a mechanism for EXTL3 regulation and tested the hypothesis that loss of EXTL3 expression is associated with mucinous differentiation and alteration of glycoprotein expression in CRC cells. The methylation status of the EXTL3 gene promoter was analysed by methylation-specific PCR following bisulphite modification in CRC cell lines and microdissected primary CRC tissues and their corresponding adjacent normal colorectal mucosa. EXTL3 promoter methylation was detected in seven of 11 mucinous CRCs (63.6%) but in none of 26 non-mucinous CRCs examined. EXTL3 promoter methylation was also detected in the normal colonic mucosa of three patients with mucinous CRC but not in the normal colonic mucosa of any patients with non-mucinous CRC. The presence of EXTL3 methylation was significantly associated with the partial loss of HS expression in mucinous CRC lesions. The mucinous CRC cell lines, Colo201 and Colo205, showed EXTL3 promoter methylation and loss of EXTL3 mRNA expression. However 5-aza-2'-deoxycytidine treatment demethylated the EXTL3 gene promoter and restored its mRNA expression. Furthermore, the basal expression of HS in CRC cells was abolished by treatment with EXTL3-siRNA. We conclude that EXTL3 promoter methylation and its related loss of EXTL3 expression are involved in the loss of HS expression in mucinous CRCs.