Promoter hypermethylation of multiple genes in early gastric adenocarcinoma and precancerous lesions

Promoter hypermethylation is an alternative mechanism of gene silencing in human cancers including gastric cancer. To date, several reports on methylation of various genes in gastric cancer have been published. However, most of these studies have focused on cancer tissues or only a single gene. In this study, we determined the methylation frequency of 5 genes, including p16, Runx3, MGMT, DAPK, and RASSF1A, by methylation-specific polymerase chain reaction, in a series of formalin-fixed paraffin-embedded tissues including normal gastric mucosa (n = 20), intestinal metaplasia (n = 14), gastric epithelial dysplasia (n = 27), and early gastric adenocarcinoma (n = 16). Immunohistochemistry was used to determine expression of MGMT and RASSF1A protein. All 20 histologically normal gastric biopsy specimens were methylation-free for all 5 genes. Aberrant hypermethylation of RASSF1A was not detected in any case from intestinal metaplasia to early gastric adenocarcinoma. The methylation rate of the other 4 genes increased with the histological progression from intestinal metaplasia to gastric epithelial dysplasia, to early gastric adenocarcinoma. Methylation was detected in 28.6% of intestinal metaplasia (4/14), in 77.8% of gastric epithelial dysplasia (21/27), and in 87.5% of early gastric adenocarcinoma (14/16). The average number of methylated genes in intestinal metaplasia, gastric epithelial dysplasia, and early gastric adenocarcinoma was 0.43, 1.3, and 1.8, respectively. Concurrent methylation in 3 or more genes was found in 7.1% of intestinal metaplasia, 11.1% of gastric epithelial dysplasia, and 31.3% of early gastric adenocarcinoma. No correlation was found between hypermethylation and other clinicopathologic parameters such as age, sex, Helicobacter pylori infection, and location of lesions. However, we observed a significant association between hypermethylation of p16 and MGMT and elevated serum carcinoembryonic antigen level. No reduction or loss of RASSF1A expression was observed in our study. Weak or loss of MGMT expression was found in 20 lesions and was significantly associated with promoter hypermethylation (P < .01). Our results suggest that promoter hypermethylation of the p16, Runx3, MGMT, and DAPK genes may play an important role in the pathogenesis of gastric precancerous lesions and early gastric adenocarcinoma. Hypermethylation and inactivation of RASSF1A, however, could be a later event in malignant transformation. Further studies are warranted to determine whether the presence of promoter hypermethylation in gastric precancerous lesions is associated with higher risk of subsequent cancer development and how to interrupt the malignant transition from intestinal metaplasia and gastric epithelial dysplasia to early gastric adenocarcinoma by developing some gene-targeting therapies that may reverse aberrant methylation.     

Gene expression profiling with microarray and SAGE identifies PLUNC as a marker for hepatoid adenocarcinoma of the stomach.

Gastric cancer is one of the most common malignancies worldwide. In this study, we screened for genes upregulated in gastric cancer by comparing gene expression profiles from serial analysis of gene expression and microarray and identified the palate, lung, and nasal epithelium carcinoma-associated protein (PLUNC) gene. Immunostaining for PLUNC in 140 gastric cancer cases revealed strong and extensive staining of PLUNC in hepatoid adenocarcinoma of the stomach, whereas 7% of conventional gastric cancer cases showed focal immunostaining of PLUNC. Gastric hepatoid adenocarcinoma is an extrahepatic tumor characterized by morphologic similarities to hepatocellular carcinoma. To investigate the utility of PLUNC immunostaining in the diagnosis of gastric hepatoid adenocarcinoma, six cases of gastric hepatoid adenocarcinoma (six primary tumors and two associated liver metastases) were studied further. PLUNC staining was observed in all six primary hepatoid adenocarcinomas. PLUNC staining was observed in both the hepatoid adenocarcinoma and tubular/papillary adenocarcinoma components of primary tumors, although PLUNC staining was preferentially localized in tubular/papillary adenocarcinoma components. Staining of PLUNC was also detected in both liver metastases. PLUNC staining was not observed in 52 cases of primary hepatocellular carcinoma or in normal adult or fetal liver. These results indicate that PLUNC is a novel marker that distinguishes gastric hepatoid adenocarcinoma from primary hepatocellular carcinoma.     

紧密连接蛋白1 mRNA和蛋白表达与胃癌侵袭转移及预后的相关性

目的 探讨紧密连接蛋白1(ZO-1)mRNA及蛋白表达在胃癌侵袭转移及预后中的意义.方法 Real-time qPCR法检测52例胃腺癌细胞ZO-1 mRNA表达,组织芯片SP免疫组织化学法检测228例胃腺癌细胞ZO-1蛋白表达定位变化情况.结果 81.1%的胃癌组织出现不同程度的ZO-1胞膜表达异位至胞质迷离表达的现...     

Decreased expression of tumour suppressor Bax-interacting factor-1 (Bif-1), a Bax activator, in gastric carcinomas

AIMS: Evasion of apoptosis is one of the hallmarks of cancer. Bax-interacting factor-1 (Bif-1) interacts with both Bax and Bak that are essential for the intrinsic pathway of apoptosis, and enhances apoptosis. The aim of this study was to explore whether alteration of Bif-1 expression might be a characteristic of gastric cancer. METHODS: We analysed the expression of Bif-1 protein in 60 gastric adenocarcinomas by immunohistochemistry using a tissue microarray approach. RESULTS: In normal gastric mucosal cells, surface and glandular epithelial cells strongly expressed Bif-1. While Bif-1 expression was detected in 24 cases (40%) of the gastric carcinomas, there was no Bif-1 immunostaining in the remaining 36 cancers. Even in the 24 cases with positive Bif-1 immunostainings, 10 cancers showed decreased intensity of immunostaining compared with the normal mucosal epithelial cells. CONCLUSION: The decreased expression of Bif-1 in malignant gastric epithelial cells compared with the normal mucosal cells suggests that loss of Bif-1 expression may play a role in gastric tumorigenesis, possibly by inhibiting the apoptosis mediated by Bif-1.     

应激猪睾丸葡萄糖转运蛋白1和葡萄糖转运蛋白2的表达与定位

目的 探讨正常和热应激条件下,葡萄糖转运蛋白1（GLUT1）和葡萄糖转运蛋白2（GLUT2）在成年猪睾丸的表达和定位。 方法 性成熟长白公猪9头,随机分为3组。局部阴囊热刺激组（n=3）,用自制电热毯置阴囊42 ℃加热1 h;环境热应激组（n=3）,每天置于37～40 ℃猪舍环境3 h,连续7 d,每天于热处理结束后,将实验猪驱赶回21～25 ℃猪舍环境;对照组（n=3）,饲养在21～25 ℃猪舍环境。局部热刺激6 h后和环境热应激处理结束24 h后,手术摘除双侧睾丸。用Real-time PCR、Western blotting和免疫组织化学技术检测猪睾丸组织内GLUT1和GLUT2的表达。 结果 Real-time PCR和Western blotting结果显示,与对照组相比,环境热应激组GLUT1蛋白和mRNA的表达差异不显著,局部阴囊热刺激组GLUT1蛋白和mRNA表达显著升高;环境热应激组和局部阴囊热刺激组,GLUT2蛋白和mRNA表达均显著升高。免疫组织化学结果发现,热处理前后,GLUT1蛋白在曲精小管内定位于精母细胞和圆形精子细胞;环境热应激组GLUT1蛋白染色与对照组相比,无明显差异,局部阴囊热刺激后,GLUT1染色变深,表达升高。热处理前后,GLUT2蛋白在曲精小管定位于生精细胞和支持细胞,环境热应激和局部阴囊热刺激导致GLUT2染色变深,表达升高。 结论 葡萄糖转运蛋白GLUT1和GLUT2表达于猪睾丸曲精小管,环境高温和阴囊局部热刺激导致GLUT1和GLUT2在猪睾丸的表达水平改变,提示这两种葡萄糖转运蛋白在猪精子发生过程中发挥重要作用。     

MRP-1/CD9基因在胃癌及其癌前病变中的差异表达

目的　筛选和鉴定与胃癌发生、发展相关的基因片段 ,探讨胃癌的癌变分子机理。方法　应用荧光 m RNA差异显示技术对胃正常黏膜、癌前病变及癌组织的基因差异表达情况进行了分析。对其中的运动相关蛋白 (motility- related protein- 1,MRP- 1/CD9)基因 ,用 Northern印迹及逆转录 -聚合酶链反应技术分析在正常及不同病理状态下该基因表达的情况。结果　Northern印迹结果与 m RNA差异显示的结果相符合 ,逆转录 -聚合酶链反应显示 MRP- 1/CD9在胃癌组织中的表达 (0 .31± 0 .18)低于相应的正常胃黏膜 (0 .4 9± 0 .2 4 )及癌前病变组织 (0 .4 7± 0 .18) ,差异有显著性 (P<0 .0 5 ) ;在胃癌中 ,MRP- 1/CD9在弥漫型胃癌中的表达 (0 .2 2± 0 .17)明显低于肠型胃癌 (0 .38± 0 .16 ) (P<0 .0 5 )。结论　与正常胃黏膜及癌前病变组织相比 ,MRP- 1/CD9基因在胃癌组织中表达明显降低 ,提示 MRP- 1/CD9基因的表达情况可能与胃癌的发病及其组织学分型有关。     

运用亚细胞蛋白质组学方法发现胃腺癌潜在标志物UCHL1

目的:通过对胃腺癌细胞系SGC7901和永生化胃正常上皮细胞系GES胞浆组分蛋白进行差异蛋白质组学分析,为胃腺癌诊断提供候选生物标志物,进而为阐明胃腺癌发病机理提供新的线索和思路。方法:运用亚细胞蛋白组份分离结合双向凝胶电泳和基质辅助激光解吸电离飞行时间质谱(MALD I-TOF-MS)技术筛选鉴定出SGC7901和GES细胞系胞浆蛋白组分间的差异蛋白质,并且利用免疫印迹和半定量RT-PCR方法对得到的差异蛋白进行验证。结果:筛选得到10个差异蛋白,进一步证实,差异蛋白泛素羧基末端水解酶-L1(UCHL1)在蛋白质和mRNA水平上,在胃癌细胞系SGC7901、AGS、BGC823和MKN45中的表达水平均低于胃正常上皮细胞系GES;其在胃癌组织中的表达水平也远远低于癌旁正常胃组织中的水平。结论:UCHL1蛋白质分子具有作为胃腺癌诊断检测标志物的潜在应用价值,为开发胃腺癌诊断标志物提供了新的候选蛋白。     

鸢尾素抑制JAK/STAT3通路促进炎症状态下的血管生成

目的　研究急性炎症状态下鸢尾素对人脐静脉内皮细胞（human umbilical vein endothelial cell,HUVEC）血管生成的影响及其机制。 方法　通过CCK-8检测不同浓度（0.1、1.0、5.0、10.0、20.0 ng/mL）的鸢尾素对HUVEC增殖的影响;用脂多糖诱导HUVEC急性炎症状态,通过划痕和成管实验,研究鸢尾素对细胞迁移及管样形成的影响,通过RT-PCR研究相关细胞因子IL-1β、IL-6、TNF-α、PDGF-BB的基因表达;Western blot检测JAK／STAT3信号通路中关键蛋白Erk1／2、Jak、Stat3的表达。 结果　各浓度的重组鸢尾素均不影响HUVEC的增殖;在急性炎症状态下,鸢尾素可以促进HUVEC细胞迁移和管样形成,并且抑制HUVEC炎症因子IL-1β、IL-6、TNF-α基因的表达,增加组织修复相关因子PDGF-BB的基因表达;鸢尾素抑制LPS诱导的JAK／STAT3通路激活。 结论　鸢尾素可以抑制JAK／STAT3信号通路,缓解LPS诱导的HUVEC急性炎症状态,促进血管新生。     

蛋白激酶WEE1在胃癌组织中的表达及其临床意义

目的　探讨蛋白激酶WEE1在胃癌组织中的表达及其与胃癌临床指标的相关性,并阐述其在胃癌发生发展中的作用。 方法　使用Oncomine数据库分析WEE1在胃腺癌和胃黏膜组织中的表达差异。选取100例胃腺癌和80例癌旁组织标本,通过免疫组织化学法和组织芯片技术检测WEE1蛋白在胃癌和癌旁组织中的表达水平。对免疫组织化学结果中染色的比例以及染色程度进行半定量分析,对半定量分析结果与胃癌临床指标进行相关性分析。使用RT-PCR和Western blotting检测WEE1在胃癌和癌旁组织中的mRNA和蛋白表达水平。 结果　WEE1在100例胃癌患者中的阳性率为86%,高表达86例,低表达14例。通过Oncomine数据库分析,蛋白激酶WEE1在胃腺癌中的表达明显高于胃黏膜组织中的表达（P<0.01）。免疫组化、RT-PCR和Western blotting均显示,WEE1在胃癌组织中的表达明显高于癌旁组织（P<0.01）;免疫组化还显示WEE1的表达量随着胃癌组织分期的增加而增加（P<0.01）。 结论　蛋白激酶WEE1在胃癌组织中高表达,提示其可作为胃癌治疗靶点之一。     

Correlation of RKIP,STAT3 and cyclin D1 expression in pathogenesis of gastric cancer

RKIP is proposed as a new metastasis suppressor. Our recent study showed that RKIP inhibits malignant phenotypes of gastric cancer cells. However, the underlying mechanism of RKIP function in gastric cancer is unclear. This study aimed to investigate the correlation of RKIP, STAT3 and cyclin D1 expression in the tumorigenesis of gastric cancer. RKIP, STAT3 and cyclin D1 proteins were detected by immunohistochemistry in tissues of gastric ulcer (n = 27), gastric adenomatous polyp (n = 7), intestinal metaplasia (n = 26), dysplasia (n = 40), gastric carcinoma (n = 169) and metastatic lymph node (n = 36). RKIP, STAT3 and cyclin D1 mRNA levels were analyzed by RT-PCR in SGC7901 cells. We found that RKIP protein expression was significantly decreased in advanced gastric cancer and metastatic lymph node tissues while cyclin D1 and STAT3 protein expression was markedly increased in severe dysplasia, gastric cancer and metastatic lymph node tissue (P < 0.01). RKIP expression in gastric cancer was negatively correlated with the invasion, TNM stage and lymphoid node metastasis (P < 0.01), while cyclin D1 and STAT3 expression was positively correlated with histological differentiation and lymphoid node metastasis (P < 0.01). RKIP protein level was negatively correlated with cyclin D1 and STAT3 protein level, while cyclin D1 protein level was positively correlated with STAT3 protein level in gastric cancer samples. Moreover, reconstitution of RKIP in SGC7901 gastric cancer cells led to reduced cyclin D1 and STAT3 mRNA levels. In conclusion, these data suggest that RKIP inhibits gastric cancer metastasis via the downregulation of its downstream target genes STAT3 and cyclin D1.     

Prognostic value of Musashi-1 in endometrioid adenocarcinoma

Aims: Musashi-1, a RNA-binding protein, is suggested to be a cancer stem cell-related marker; its high level of protein expression is reported to be associated with high histological grade in some tumors. The aim of this study was to investigate the prognostic value of Musashi-1 in patients with endometrioid adenocarcinoma (EAC). Methods: We examined the Musashi-1 mRNA expression level in 35 fresh EAC tissue samples and 15 normal endometrium samples by real-time RT-PCR, and its protein expression level in 148 paraffin EAC tissue samples and 20 paraffin normal endometrium samples by immunohistochemistry. The correlation between Musashi-1 and overall survival (OS) used Cox proportional hazards regression. The prognostic accuracy of Musashi-1 compared with other clinicopathological risk factors by logistic regression. Furthermore, we examined whether Musashi-1 expression is correlated with another cancer stem cell marker CD133 by real-time RT-PCR. Results: Musashi-1 mRNA expression of EAC is 2.8-fold higher than that of normal endometrium (P = 0.0009). Musashi-1 protein expression level is correlated with tumor stage, grade and vascular invasion. Patients with higher protein expression level of Musashi-1 are associated with poor survival rate than those with negative or low level of expression (HR = 2.073, P = 0.001). The area under the curve (AUC) for Musashi-1 is 0.8, which is higher than other clinicopathological factors (P = 0.000). In addition, Musashi-1 mRNA expression seems to be closely correlated with CD133 expression (r = 0.7167, P < 0.0001). Conclusions: Our results suggest high level of Musashi-1 protein expression is associated with poor survival in EAC patients, which may be an independent prognostic factor for EAC.     

DARPP-32在胃癌中的表达及其意义

目的 探讨DARPP-32蛋白在胃癌组织、细胞系及耐药细胞系中的表达及意义。方法用免疫组织化学SABC法检测96例胃癌组织及57例正常胃黏膜中DARPP-32的表达,用Western蛋白印迹检测胃癌组织及细胞系中DARPP-32的表达。结果 胃腺癌组织中DARPP-32的表达率(92.7％,89/96)显著高于正常胃组织(52.6％,30/57,P<0.05),且DARPP-32表达与胃腺癌的分化、浸润、转移无关(P>0.05)。在胃癌患者的癌组织中DARPP-32和剪切产物t-DARPP均表达,其表达水平显著高于其癌旁组织(t=2.45,P=0.015),并以t-DARPP的表达为主。在人胃癌细胞系中也存在DARPP-32和t-DARPP的表达,而且DARPP-32在SGC7901耐药细胞株SGC7901/VCR和SGC7901/ADR中的表达水平较其亲本细胞明显下调。结论 DARPP-32在胃腺癌组织中的表达增高,DARPP-32参与胃癌的发生,其信号转导通路可能存在于胃上皮细胞,并与胃癌的发生及多药耐药相关。     

STC1在胃癌组织与外周血液中表达的意义

目的：研究外周血液与胃癌组织中斯钙素1 (STC1)的表达情况。方法: 分别在I-IV型的胃癌74例患者中，应用RT-PCR法检测外周血和肿瘤组织中STC1 mRNA表达情况，应用免疫组化法检测肿瘤组织中STC1蛋白表达情况。结果: 74例胃癌患者，48例外周血液中STC1 mRNA阳性；肿瘤组织STC1 mRNA与STC1蛋白全部表达。外周血中STC1 mRNA与肿瘤淋巴结转移数、肿瘤大小和病理TNM分期有(r分别为0.637、0.519、0.541, P<0.05、P<0.01、P<0.05)显著正相关。结论: STC1在胃癌的发生发展过程中具有抑制免疫系统功能等重要作用；外周血中STC1 mRNA检测可试用作为肿瘤微转移的1个新指标。     

Tiam1表达与胃癌侵袭转移关系的临床和实验研究

目的检测T淋巴瘤侵袭转移诱导因子1(Tiam1)在正常胃黏膜组织、胃癌组织以及胃癌细胞系中的表达,探讨其与胃癌侵袭转移的关系。方法(1)应用免疫组化SABC法检测60例胃癌及正常胃黏膜组织中Tiam1蛋白的表达并分析其与胃癌临床病理参数间的关系。(2)应用逆转录PCR和SABC免疫组化技术分别检测Tiam1mRNA与蛋白在胃癌MKN45细胞(MO)及其高(MH)、低(ML)侵袭转移亚株中的表达,分析其与胃癌细胞侵袭转移能力的关系。结果(1)Tiam1蛋白在正常胃黏膜组织中阴性表达显著低于癌组织(0vs78.3%),两者差异有统计学意义(P<0.01),且随胃癌组织分化程度的降低、浸润深度的增加、TNM分期的升高及伴有淋巴结转移,Tiam1蛋白染色阳性率逐渐升高,差异有统计学意义(P<0.05)。但Tiam1蛋白表达水平与胃癌患者的性别、年龄、部位及癌肿大小无关,差异无统计学意义(P>0.05)。(2)Tiam1mRNA和蛋白在胃癌MKN45细胞高侵袭转移亚株中的表达均较其在MKN45细胞及低侵袭转移亚株中的表达为强,差异有统计学意义(P<0.05)。结论Tiam1表达与胃癌侵袭转移能力呈正相关,且其有可能成为反映胃癌恶性生物学行为的一种新型标志物。     

GLUT1 and GLUT8 in endometrium and endometrial adenocarcinoma.

Glucose is provided to cells by a family of glucose transport facilitators known as GLUTs. These transporters are expressed in a tissue specific manner and are overexpressed in many primary tumors of these tissues. Regulation of glucose transport facilitator expression has been demonstrated in endometrial tissue and endometrial adenocarcinoma. The following experiments were conducted to quantify and localize the expression of GLUT1 and GLUT8 in benign endometrium and compare this expression to endometrial cancer. Endometrial tissue samples were obtained from random hysterectomy specimens of patients with benign indications for surgery and endometrial cancer. Immunoblot and immunolocatization studies were performed using GLUT1 and GLUT8 specific antisera. Endometrial samples from 65 women who had undergone hysterectomy were examined (n=38 benign, n=27 malignant). A 44 and a 35.4 kDa immunoreacive species was demonstrated in endometrium and endometrial cancer for GLUT1 and GLUT8, respectively. Upregulation of GLUT1 expression was demonstrated with increasing grade of tumors (P<0.002). GLUT8 expression was increased in all tumor subtypes compared to atrophic endometrium (P<0.001). Apical localization by GLUT1 and GLUT8 was demonstrated in endometrial glands. GLUT1 and GLUT8 demonstrated diffuse intracellular localization in the cancer subtypes. GLUT1 and GLUT8 are expressed in both human endometrium and endometrial cancer. There appears to be a step-wise progression in GLUT1 and GLUT8 expression as tumor histopathology worsens. GLUT1 and GLUT8 may be important markers in tumor differentiation, as well as providing energy to rapidly dividing tumor cells.     

VIP在胃腺癌中的表达及临床意义的研究

目的 研究血管活性肠肽(VIP)在胃腺癌组织和血浆中的表达及其与临床病理因素的关系.方法 采用ELISA法检测胃腺癌患者血浆中和正常对照组的VIP水平.RT-PCR方法检测VIPmRNA在胃腺癌组织、其相邻的正常胃腺癌组织及不典型增生胃黏膜的差异表达量,Western Blot法进一步检测胃腺癌组织中VLP蛋白的表达.结果 ELISA法检测正常人血浆vIP水平为(5.794±0.014)ng/ml,胃腺癌患者血浆中的VIP水平为(14.437±0.825)ng/ml.两者差异有统计学意义(P<0.05).RT-PCR分析胃腺癌组织中VIP mRNA的V/B值明显高于不典型增生胃黏膜及相应的癌旁正常胃黏膜,其V/B值分别为:(1.5261±0.3028)、(0.9334 ±0.2872)、(0.9051±0.2794),差异有统计学意义(P<0.01);正常胃窦黏膜与不典型增生胃黏膜中.V/B值的差异无统计学意义(P0.05);不同分化程度的胃腺癌组织VIP mRNA表达量的差异有统计学意义(P<0.05);有淋巴结转移与无淋巴结转移的胃腺癌组织VIP mRNA表达量之间差异亦有统计学意义(P<0.05).Western Blot法检测胃腺癌组织VIP蛋白表达量高于正常组织.结论 VIP可能参与了胃腺癌的发生.VIP蛋白的过度表达可能与胃腺癌的分化程度、侵袭有关,其表达对判断预后有参考价值.     

Expression of SNCG,MAP2, SDF-1 and CXCR4 in gastric adenocarcinoma and their clinical significance

Objectives: The purpose of the study was to detect the expression of SNCG, MAP2, SDF-1 and CXCR4 in gastric adenocarcinoma, and to evaluate their roles in the carcinogenesis of gastric adenocarcinoma, development, invasion and metastasis as well as their clinical significance. Methods: The expression of SNCG, MAP2, SDF-1 and CXCR4 was detected by SP immunohistochemical method in 225 cases of gastric adenocarcinoma and 105 cases of nonneoplastic adjacent gastric tissue. The expression of SNCG, MAP2, SDF-1 and CXCR4 mRNA was also detected by RT-PCR method in 50 cases of gastric adenocarcinoma and 30 cases of nonneoplastic adjacent gastric tissue. Results: The expression of SNCG, MAP2, SDF-1 and CXCR4 in the gastric adenocarcinoma was remarkably higher than those in the nonneoplastic adjacent gastric tissue (P < 0.01); The positive expression of SNCG and MAP2 was correlated with the depth of tumor invasion and the metastasis of lymph nodes (P < 0.05), and that of SDF-1 and CXCR4 was correlated with the metastasis of lymph nodes (P < 0.05). Conclusions: SNCG, MAP2, SDF-1 and CXCR4 may play an important role in the carcinogenesis, progression, invasion and metastasis of gastric adenocarcinoma. However, it still needs more exploration whether they can serve as promising therapeutic targets of gastric adenocarcinoma.