The insulin receptor substrate 1 (IRS1) in intestinal epithelial differentiation and in colorectal cancer

Colorectal cancer (CRC) is associated with lifestyle factors that affect insulin/IGF signaling, of which the insulin receptor substrate 1 (IRS1) is a key transducer. We investigated expression, localization and pathologic correlations of IRS1 in cancer-uninvolved colonic epithelium, primary CRCs with paired liver metastases and in vitro polarizing Caco2 and HT29 cells. IRS1 mRNA and protein resulted higher, relative to paired mucosa, in adenomas of familial adenomatous polyposis patients and in CRCs that overexpressed c-MYC, ß-catenin, InsRß, and IGF1R. Analysis of IRS1 immunostaining in 24 cases of primary CRC with paired colonic epithelium and hepatic metastasis showed that staining intensity was significantly higher in metastases relative to both primary CRC (P<0.01) and colonic epithelium (P<0.01). Primary and metastatic CRCs, compared to colonic epithelium, contained significantly higher numbers of IRS1-positive cells (P = 0.013 and P = 0.014, respectively). Pathologic correlations in 163 primary CRCs revealed that diffuse IRS1 staining was associated with tumors combining differentiated phenotype and aggressive markers (high Ki67, p53, and ß-catenin). In Caco 2 IRS1 and InsR were maximally expressed after polarization, while IGF1R was highest in pre-polarized cells. No nuclear IRS1 was detected, while, with polarization, phosphorylated IRS1 (pIRS1) shifted from the lateral to the apical plasma membrane and was expressed in surface cells only. In HT29, that carry mutations constitutively activating survival signaling, IRS1 and IGF1R decreased with polarization, while pIRS1 localized in nuclear spots throughout the course. Overall, these data provide evidence that IRS1 is modulated according to CRC differentiation, and support a role of IRS1 in CRC progression and liver metastatization.     

Expression Profile of the REG Gene Family in Colorectal Carcinoma

Regenerating (REG) gene family belongs to the calcium-dependent lectin gene superfamily and encodes small multifunctional secretory proteins, which might be involved in cell proliferation, differentiation, and carcinogenesis. To clarify REG expression profile in colorectal carcinoma (CRC), the authors examined the expression of REG Iα, Iβ, III, HIP/PAP, and REG IV by immunohistochemistry on tissue microarray. The expression of REG Iα, III, and HIP/PAP was more frequently observed in the CRCs than adjacent non-neoplastic mucosa (p < 0.001), whereas it was the converse for REG Iβ and IV (p < 0.001). The expression of REG Iα, Iβ, III, and HIP/PAP was negatively correlated with the depth of invasion of CRCs (p < 0.05). The REG Iβ and HIP/PAP were less expressed in CRCs with than without venous invasion (p < 0.05). The positive rates of REG Iα and HIP/PAP were significantly higher in CRCs without than with lymph node metastasis (p < 0.05). Mucinous carcinoma more frequently expressed REG IV protein than well- and moderately differentiated ones (p < 0.05). There was a positive relationship between REG Iα, Iβ, III, and HIP/PAP expression (p < 0.05). Survival analysis indicated the REG Iβ or HIP/PAP expression was positively linked to favorable prognosis of carcinoma patients (p < 0.05). This study indicated that aberrant REG expression might be closely linked to the pathogenesis, invasion, or lymph node metastasis of CRCs. REG Iβ and HIP/PAP could be considered reliable markers of favorable prognosis of CRC patients.     

Downregulation of exosome-encapsulated miR-548c-5p is associated with poor prognosis in colorectal cancer

The role of circulating exosomal microRNAs (miRNAs) in colorectal cancer (CRC) has drawn more and more attention during the past few years. Previously, we have identified several specific miRNAs in serum exosomes as potential CRC biomarkers. However, little is known about the association between exosome-encapsulated miR-548c-5p and outcomes of patients with CRC. In the current study, the expression of serum exosomal miR-548c-5p was investigated by quantitative real-time polymerase chain reaction. Its correlation with CRC prognosis was estimated by Kaplan-Meier survival and log-rank tests. Cox regression analysis based on uni- and multivariate analyses was performed to estimate the relationship of exosome-encapsulated miR-548c-5p with the clinicopathological factors of patients with CRC. Reduced levels of serum exosomal miR-548c-5p were more significant in CRC patients with liver metastasis and at later TNM stage (III/IV tumor stages). Serum exosomal miR-548c-5p could inhibit the proliferation of CRC cells, while the precise molecular mechanisms warranted further elucidation. In addition, decreased levels of serum exosomal miR-548c-5p were independently associated with shorter overall survival in CRC adjusted by age, sex, tumor grade vascular infiltration, TNM stage (III/IV tumor stages) and metastasis (hazard ratio = 3.40, 95% confidence interval 1.02-11.27; P = 0.046). The downregulation of exosomal miR-548c-5p in serum predicts poor prognosis in patients with CRC. Exosomal miR-548c-5p may be a critical biomarker for CRC diagnosis and prognosis.     

RAD50/MRE11/NBS1 proteins in relation to tumour development and prognosis in patients with microsatellite stable colorectal cancer

RAD50/MRE11/NBS1 complex is essential for DNA double-strand break repair and for maintaining genomic integrity. In this study, we immunohistochemically examined MRE11, NBS1 and RAD50 expression in primary CRCs (n=208), the corresponding distant (n=41) and adjacent normal mucosa (n=130), and lymph node metastases (n=26), and investigated their clinicopathological significance in colorectal cancers (CRCs). We found that the intensity and percentage of MRE11 and NBS1 in primary CRCs were positively correlated with each other and with RAD50 (P<0.0001). Strong expression of MRE11, NBS1 or combined RAD50/MRE11/NBS1 was related to MSS, positive hMLH1 expression, earlier tumour stage (TNM stage I and II) and favourable survival (P<0.05). A high percentage of MRE11 expression was associated with less local recurrence and high apoptotic activity (P<0.05). In MSS CRCs, the expression of MRE11 and NBS1 was stronger than that in normal mucosa (P<0.05), and strong expression of NBS1 in primary tumour was related to favourable survival of patients in TNM stage I and II (univariate analysis: P=0.03; multivariate analysis: P=0.07). In MSI CRCs, neither MRE11 nor NBS1 expression showed differences among normal mucosa, primary tumour and metastasis, or among clinicopathological variables. In conclusion, RAD50/MRE11/NBS1 proteins interacted with each other, which had different clinicopathological significance in MSS and MSI CRCs, and further, each component of the complex might have additional roles. NBS1 might be a prognostic factor for patients with MSS tumour in TNM stage I and II.     

SVM-T-RFE: a novel gene selection algorithm for identifying metastasis-related genes in colorectal cancer using gene expression profiles

Although metastasis is the principal cause of death cause for colorectal cancer (CRC) patients, the molecular mechanisms underlying CRC metastasis are still not fully understood. In an attempt to identify metastasis-related genes in CRC, we obtained gene expression profiles of 55 early stage primary CRCs, 56 late stage primary CRCs, and 34 metastatic CRCs from the expression project in Oncology (http://www.intgen.org/expo/). We developed a novel gene selection algorithm (SVM-T-RFE), which extends support vector machine recursive feature elimination (SVM-RFE) algorithm by incorporating T-statistic. We achieved highest classification accuracy (100%) with smaller gene subsets (10 and 6, respectively), when classifying between early and late stage primary CRCs, as well as between metastatic CRCs and late stage primary CRCs. We also compared the performance of SVM-T-RFE and SVM-RFE gene selection algorithms on another large-scale CRC dataset and the five public microarray datasets. SVM-T-RFE bestowed SVM-RFE algorithm in identifying more differentially expressed genes, and achieving highest prediction accuracy using equal or smaller number of selected genes. A fraction of selected genes have been reported to be associated with CRC development or metastasis.     

Hypermethylation of 5'CpG island of p14ARF flanking exon 1 Beta in human colorectal cancers displaying a restricted pattern of p53 overexpression concomitant with increased MDM2 expression

ABSTRACT: BACKGROUND: It has been suggested that inactivation of p14ARF, a tumor suppressor central to regulating p53 protein stability through interaction with the MDM2 oncoprotein, abrogates p53 activity in human tumors retaining the wild-type TP53 gene. Differences in expression of tumor suppressor genes are frequently associated with cancer. We previously reported on a pattern of restricted p53 immunohistochemical overexpression significantly associated with microsatellite instability (MSI), low TP53 mutation frequency, and MDM2 overexpression in colorectal cancers (CRCs). In this study, we investigated whether p14ARF alterations could be a mechanism for disabling the p53 pathway in this subgroup of CRCs. RESULTS: Detailed maps of the alterations in the p14ARF gene were determined in a cohort of 98 CRCs to detect both nucleotide and copy-number changes. Methylation-specific PCR combined with bisulfite sequencing was used to evaluate the prevalence and distribution of p14ARF methylation. p14ARF alterations were then correlated with MSI status, TP53 mutations, and immunohistochemical expression of p53 and MDM2. The frequency of p14ARF mutations was extremely low (1/98; 1%), whereas coexistence of methylated and unmethylated alleles in both tumors and normal colon mucosa was common (91/98; 93%). Only seven of nine tumors (7%) had a distinct pattern of methylation compared with normal colon mucosa. Evaluation of the prevalence and distribution of p14ARF promoter methylation in a region containing 27 CpG sites in 35 patients showed a range of methylated CpG sites in tumors (0 to 25 (95% CI 1 to 13) versus 0 to 17 (95% CI 0 to 2)) in adjacent colon mucosa (P = 0.004). Hypermethylation of the p14ARF promoter was significantly correlated with the restricted p53 overexpression pattern (P = 0.03), and MDM2 overexpression (P = 0.02), independently of MSI phenotype. Although no significant correlation between p14ARF methylation and TP53 mutational status was seen (P = 0.23), methylation involving the proximal CpG sites within the 5' CpG flanking exon 1beta was present more frequently in tumors with restricted p53 overexpression than in those with diffuse p53 overexpression (range of methylated clones 17 to 36% (95% CI 24 to 36%) versus range 0 to 3% (95% CI 0 to 3%), P = 0. 0003). CONCLUSION: p14ARF epigenetic silencing may represent an important deregulating mechanism of the p53- MDM2-p14ARF pathway in CRCs exhibiting a restricted p53 overexpression pattern.     

Fascin在结肠癌中表达的临床病理学研究

目的:Fascin是一种肌动蛋白结合蛋白,在多种上皮性肿瘤中高表达并与肿瘤侵袭有关。在本研究中观察fascin在结肠癌中表达及探讨其临床病理意义,为其在结肠癌早期诊断和预后预测方面的应用提供依据。方法:应用免疫组织化学技术检测Fascin在结肠肿瘤中的表达,并分析其表达的结肠癌临床病理意义。结果:Fascin在癌旁肠粘膜、腺瘤、腺癌中表达有显著性差异,其中癌旁肠粘膜组和腺瘤组阳性表达率无显著性差异(X2=0.344,P0.05),腺癌组阳性表达率显著高于癌旁粘膜组(X2=8.492,P0.0,1),腺癌组阳性表达率显著高于腺瘤组(X2=7.450,P0.01)。Fascin表达与结肠癌患者的年龄、性别、肿瘤浸润肠壁深度、淋巴结转移、分化程度无显著相关性,而在中-晚期病例(III/IV期)中的表达率显著高于早期病例(P0.05)。Fascin表达阳性病例的生存期显著高于Fascin表达阴性病例(P0.022)。结论:Fascin表达与结肠癌发生和预后密切相关,可能作为结肠癌早期诊断和预后的标志物。     

Src family kinases,HCK and FGR,associate with local inflammation and tumour progression in colorectal cancer

BackgroundIn colorectal cancer (CRC), inflammatory responses have been reported to associate with patient survival. However, the specific signalling pathways responsible for regulating inflammatory responses are not clear. Src family kinases (SFKs) impact tumourigenic processes, including inflammation.MethodsThe relationship between SFK expression, inflammatory responses and cancer specific survival (CSS) in stage I-III CRC patients was assessed using immunohistochemistry on a 272 patient discovery cohort and an extended 822 patient validation cohort.ResultsIn the discovery cohort, cytoplasmic FGR associated with improved CSS (P = 0.019), with membrane HCK (p = 0.093) trending towards poorer CSS. In the validation cohort membrane FGR (p = 0.016), membrane HCK (p = 0.019), and cytoplasmic HCK (p = 0.030) all associated with poorer CSS. Both markers also associated with decreased proliferation and cytotoxic T-lymphocytes (all p < 0.05). Furthermore, cytoplasmic HCK was an independent prognostic marker compared to common clinical factors. To assess synergy a combine FGR + HCK score was assessed. The membrane FGR + HCK score strengthened associations with poor prognosis (p = 0.006), decreased proliferation (p < 0.001) and cytotoxic T-lymphocytes (p < 0.001).ConclusionsSFKs associate with prognosis and the local inflammatory response in patients with stage I-III CRC. Active membrane FGR and HCK work in parallel to promote tumour progression and down-regulation of the local inflammatory lymphocytic response.     

Identification of IMPA2 as the hub gene associated with colorectal cancer and liver metastasis by integrated bioinformatics analysis

Background and ObjectivesColorectal cancer (CRC) is one of the most common malignant tumors worldwide with high incidence and mortality rate, while colorectal liver metastasis (CRLM) is one of the major causes of cancer-related deaths. Therefore, the present study aims to identify the hub gene associated with CRC carcinogenesis and liver metastasis, and then explore its diagnostic and prognostic value as well as the potential regulation mechanism.MethodsThe overlapping differential co-expression genes among CRC, CRLM, and normal tissues were explored on the GSE49355 and GSE81582 datasets from the Gene Expression Omnibus (GEO) database by integrated bioinformatics analysis. Then, the hub prognostic genes were selected from the overlapping genes by univariate Cox proportional hazard analysis and online database Gene Expression Profiling Interactive Analysis 2 (GEPIA2). Subsequently, the clinical value of the hub genes was evaluated in the TCGA and GSE39582 cohorts. Finally, the underlying mechanisms of the hub gene regulating CRC carcinogenesis and metastasis were explored by Gene function annotation and DNA methylation analysis.ResultsInositol mono-phosphatase 2 (IMPA2) was identified as the hub gene associated with CRC carcinogenesis and liver metastasis. IMPA2 had an excellent diagnostic efficiency, and its expression was significantly decreased in CRC and liver metastasis samples, being positively correlated with poor prognosis. Moreover, its low expression was associated with AJCC stage III+IV, T4, N1+2, and M1. In addition, our results revealed that the potential mechanisms used by IMPA2 to mediate CRC carcinogenesis and metastasis could be associated with lipid metabolism and epithelial mesenchymal transition (EMT). Finally, IMPA2 expression could be regulated by DNA methylation.ConclusionsIMPA2 was identified and reported for the first time as a hub gene biomarker in the diagnosis and prognosis of CRC, which could regulate CRC carcinogenesis and liver metastasis through the regulation of lipid metabolism, EMT, and DNA methylation.     

大肠癌组织中联合检测USP22和BMI-1表达的临床意义

目的:探讨大肠癌组织中联合检测USP22和BMI-1表达的临床意义。方法:应用定量RT-PCR检测82例大肠癌手术切除标本及相应的癌旁组织中USP22及BMI-1 mRNA的表达水平,并分析其表达的差异,研究其表达水平与大肠癌患者临床病理特征及预后的关系。结果:USP22、BMI-1 mRNA在大肠癌及癌旁组织中均可被检出,大肠癌组织中USP22、BMI-1 mRNA的相对表达水平均显著高于癌旁组织(P0.01),且二者之间呈显著正相关(r=0.708,P0.01)。USP22、BMI-1 mRNA的高表达均与大肠癌的美国癌症分期联合委员会(AJCC)分期密切相关(P0.01)。COX回归分析显示USP22及BMI-1的共表达可作为大肠癌患者预后的独立预测因素(P0.01)。结论:USP22和BMI-1的共同激活可促进大肠癌的进展,并预示预后不良。     

Activated cMET and IGF1R-Driven PI3K Signaling Predicts Poor Survival in Colorectal Cancers Independent of KRAS Mutational Status

Background

Oncogenic mutational analysis provides predictive guidance for therapeutics such as anti-EGFR antibodies, but it is successful only for a subset of colorectal cancer (CRC) patients.

Method

A comprehensive molecular profiling of 120 CRC patients, including 116 primary, 15 liver metastasis, and 1 peritoneal seeding tissue samples was performed to identify the relationship between v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) WT and mutant CRC tumors and clinical outcomes. This included determination of the protein activation patterns of human epidermal receptor 1 (HER1), HER2, HER3, c-MET, insulin-like growth factor 1 receptor (IGF1R), phosphatidylinositide 3-kinase (PI3K), Src homology 2 domain containing (Shc), protein kinase B (AKT), and extracellular signal-regulated kinase (ERK) kinases using multiplexed collaborative enzyme enhanced reactive (CEER) immunoassay.

Results

KRAS WT and mutated CRCs were not different with respect to the expression of the various signaling molecules. Poor prognosis in terms of early relapse (<2 years) and shorter disease-free survival (DFS) correlated with enhanced activation of PI3K signaling relative to the HER kinase pathway signaling, but not with the KRAS mutational status. KRAS WT CRCs were identified as a mixed prognosis population depending on their level of PI3K signaling. KRAS WT CRCs with high HER1/c-MET index ratio demonstrated a better DFS post-surgery. c-MET and IGF1R activities relative to HER axis activity were considerably higher in early relapse CRCs, suggesting a role for these alternative receptor tyrosine kinases (RTKs) in driving high PI3K signaling.

Conclusions

The presented data subclassified CRCs based on their activated signaling pathways and identify a role for c-MET and IGF1R-driven PI3K signaling in CRCs, which is superior to KRAS mutational tests alone. The results from this study can be utilized to identify aggressive CRCs, explain failure of currently approved therapeutics in specific CRC subsets, and, most importantly, generate hypotheses for pathway-guided therapeutic strategies that can be tested clinically.     

AnnexinⅠ蛋白在人前列腺癌中的表达及临床意义

目的：探讨AnnexinⅠ蛋白在前列腺癌组织中的表达及其与前列腺癌发生、发展、转移及预后的关系。方法：回顾性分析110例前列腺癌及40例前列腺增生组织中AnnexinⅠ蛋白的表达与前列腺癌Gleason分级、年龄、临床分期、转移及预后的相关性。结果：前列腺癌患者的AnnexinⅠ表达水平显著地低于良性前列腺增生症患者（P〈0．05）;AnnexinⅠ在低分化癌中表达较高,与高、中分化癌相比有显著性差异（P〈0．05）;而高、中分化癌之间AnnexinⅠ表达均较低,两者之间无显著性差异（P〉0．05）。前列腺癌AnnexinⅠ蛋白表达与年龄无关,而与临床分期、淋巴结转移及预后有关（P〈0．05）。结论：AnnexinⅠ蛋白表达下调与前列腺癌发生发展和预后密切相关,可作为反映前列腺癌生物学行为和判断预后的生物标记物.     

DNA methylation profiles of primary colorectal carcinoma and matched liver metastasis

Background

The contribution of DNA methylation to the metastatic process in colorectal cancers (CRCs) is unclear.

Methods

We evaluated the methylation status of 13 genes (MINT1, MINT2, MINT31, MLH1, p16, p14, TIMP3, CDH1, CDH13, THBS1, MGMT, HPP1 and ERα) by bisulfite-pyrosequencing in 79 CRCs comprising 36 CRCs without liver metastasis and 43 CRCs with liver metastasis, including 16 paired primary CRCs and liver metastasis. We also performed methylated CpG island amplification microarrays (MCAM) in three paired primary and metastatic cancers.

Results

Methylation of p14, TIMP3 and HPP1 in primary CRCs progressively decreased from absence to presence of liver metastasis (13.1% vs. 4.3%; 14.8% vs. 3.7%; 43.9% vs. 35.8%, respectively) (P<.05). When paired primary and metastatic tumors were compared, only MGMT methylation was significantly higher in metastatic cancers (27.4% vs. 13.4%, P = .013), and this difference was due to an increase in methylation density rather than frequency in the majority of cases. MCAM showed an average 7.4% increase in DNA methylated genes in the metastatic samples. The numbers of differentially hypermethylated genes in the liver metastases increased with increasing time between resection of the primary and resection of the liver metastasis. Bisulfite-pyrosequencing validation in 12 paired samples showed that most of these increases were not conserved, and could be explained by differences in methylation density rather than frequency.

Conclusions

Most DNA methylation differences between primary CRCs and matched liver metastasis are due to random variation and an increase in DNA methylation density rather than de-novo inactivation and silencing. Thus, DNA methylation changes occur for the most part before progression to liver metastasis.     

Sequential biphasic changes in claudin1 and claudin4 expression are correlated to colorectal cancer progression and liver metastasis

Terminal progression of colorectal cancer (CRC) culminates in liver metastasis. To identify genes that are involved in the metastatic phenotype, cDNA microarrays were used to analyse mRNA expression profiles of colorectal carcinoma (CC)531 rat colon adenocarcinoma cells for changes related to their homing into the liver. Briefly, CC531 cells were intraportally implanted into the liver of Wag-Rij rats and re-isolated after 3, 6, 9, 14 and 21 days. Compared to control CC531 cells, claudin1 and claudin4 were among the ≥8-fold initially down-regulated genes. The co-culture of tumour cells with isolated rat hepatocytes and Kupffer cells did not induce down-regulation of either claudin1 or 4. When the environment effective on circulating tumour cells was simulated by cell culture conditions favouring their adhesion, only claudin4 showed augmented expression. Knockdown of claudin1 and claudin4 mediated by small interfering RNA caused significantly increased migration and decreased clonogenic growth of tumour cells (P < 0.05), but had no effect on their proliferation. These experimental results were paralleled by increased claudin1 and claudin4 expression in human CRC samples in Union for International Cancer Control (UICC) stages I-III, as evaluated by real-time PCR. Increased claudin4 levels were correlated with significantly reduced overall survival (log-rank test, P= 0.018). Further, significantly (P < 0.05) reduced expression of claudin1 and claudin4 was observed in stage IV and liver metastasis by immunohistochemistry. In conclusion, sequential biphasic changes in claudin1 and claudin4 expression occur during the homing of rat CC531 CRC cells to the liver. This modulation is reflected by significant changes in claudin expression in human primary and metastatic CRC.     

人口腔鳞癌组织中HIF—1a和NF—κB的表达及意义

目的：探讨缺氧诱导因子（HIF—1a）和核因子-κB（NF—κB）口腔鳞癌中的表达及相互关系,研究它们的表达与肿瘤临床病理指标的联系。方法：应用SP染色法检测HIF—1a和NF—κB在49例口腔鳞癌组织、10例正常口腔黏膜组织中的阳性率。结果在口腔鳞癌中HIF—1a和NF—κB的阳性表达率分别为80．0％和78．4％,其阳性率及表达等级均显著高于正常对照组（P〈0．05）,在中-低分化组和有淋巴结转移组中的表达显著高于高分化组和无淋巴结转移组（P〈0．05）。HIF—1a表达与NF—κB表达成等级正相关（r=0．45,P〈0．05）。结论：HIF-1a或NF—κB与口腔鳞癌生物学行为有密切关系,二者的联合检测,有助于口腔鳞癌恶性程度和生物学特性的判断。     

High-frequency microsatellite instability and BRAF mutation (V600E) in unselected Serbian patients with colorectal cancer

Microsatellite instability (MSI) is a genetic consequence of a MisMatch Repair defect in colorectal cancer (CRC). We compared clinicopathohistological features with MSI status of CRC and evaluated prognostic significance of MSI status and BRAF mutation in the group of MSI-H tumors. 155 primary CRCs were excised surgically, 2006–2008. MSI analysis was carried out using a fluorescence-based pentaplex polymerase chain reaction technique. BRAF mutation (V600E) was analyzed by direct sequencing in MSI-H tumors. For all patients were evaluated: age, gender, localization, tumor cell type, tumor differentiation, mucin production, lymphocytic infiltration (TILs) and TNM stage. Patients’ disease-free survival (DFS) was compared according to MSI and BRAF status using Kaplan–Meier test. Of the 155 CRCs, 19 (12.3%) were MSI-H, and 136 (87.7%) were MSS/L. BRAF mutations were found in 4 of the MSI-H tumors. Patients with MSI-H CRC had lower recurrence rate (log rank test; P = 0.04) than MSS/L group. Patients with MSI-H tumor and BRAF mutation had worse DFS than MSI-H tumors without this mutation (log rank test; P = 0.01). Most of the clinicopathologic characteristics of MSI-H CRC in Serbian patients are similar to those reported in previous studies. Patients with MSI tumor phenotype had favourable prognosis, but in those with BRAF mutation higher recurrence rate was observed.     

Overexpression of ZEB1 associated with metastasis and invasion in patients with gastric carcinoma

The aim of this study was to investigate the expression of ZEB1 in gastric carcinoma, its correlation with the clinicopathology of gastric carcinoma, and the role of ZEB1 in invasion and metastasis in gastric carcinoma. ZEB1 expression was analyzed by immunohistochemistry and Western blot in 45 gastric carcinoma tissue samples that contained the adjacent gastric mucosa. The correlation between ZEB1 expression, the occurrence and development of gastric cancer, and clinical pathology was investigated. ZEB1 expression in the human gastric carcinoma cell line AGS was downregulated by RNA interference, and changes in ZEB1 expression corresponded with changes in the invasive and metastatic ability of AGS cells. Immunohistochemistry revealed that ZEB1 protein expression in gastric carcinoma tissues was significantly higher than in normal gastric mucosa tissues (p < 0.001). A lower degree of differentiation of gastric cancer (p = 0.009), a higher TNM (tumor, node, and metastasis) stage (p = 0.010), and a larger scope of invasion were correlated with higher expression of ZEB1 (p = 0.041, 0.002). However, the expression of ZEB1 in gastric carcinoma tissue was independent of gender, age, and tumor size (p > 0.05). Western blot results also showed that ZEB1 protein expression was significantly higher in gastric carcinoma tissue than in the adjacent normal gastric mucosa tissue (p = 0.008). A lower degree of differentiation of the gastric carcinoma correlated with a higher TNM stage, and a larger scope of invasion correlated with increased ZEB1 expression (p = 0.023). Transfection of ZEB1 siRNA in AGS cells significantly decreased the expression level of ZEB1 protein (p = 0.035). Furthermore, the number of cells that could pass through the Transwell chamber was significantly lower in the transfected group than in the non-transfected control group (p = 0.039), indicating that the suppression of ZEB1 expression could significantly reduce the invasive and metastatic ability of AGS cells (p = 0.005). Concluding, in gastric carcinoma tissue, overexpression of ZEB1 may be related to the occurrence and development as well as invasion and metastasis of gastric carcinoma.