The combined expression of metaplasia biomarkers predicts the prognosis of gastric cancer

Analysis of Molecular Genetic Variants of Lgals4 in Esophageal Cancer: A Preliminary Report

Esophageal cancer is the eighth most common cancer worldwide and fourth most common in developing countries. Altered glycosylation pattern of cell membrane molecules along with inflammation is a characteristic attribute of oncogenesis. Galectin-4, a tandem repeat galectin, has shown effect on cancer progression/metastasis in digestive system cancers. This role of galectin-4 can be attributed to variations in LGALS4, gene encoding galectin-4. The present case-control study was designed to analyze four intronic SNPs in LGALS4 with susceptibility toward esophageal cancer.Esophageal cancer cases and age- and gender-matched apparently healthy individuals were recruited for the present study. Genotyping of rs8113319, rs4802886, rs4802887, and rs12610990 was carried out using Sanger sequencing and PCR-RFLP. MedCalc software, SNPStats and SHEsis online platform were used for statistical analysis.Genotypic analyses revealed an overall increased heterozygosity of rs12610990, rs4802886, and rs4802887, and AA genotype of rs8113319 in the study participants. Haplotypic analyses also revealed a predominance of AAAT haplotype in the cases. Moreover, combined presence of wild alleles of rs4802886 and rs4802887 could influence protection toward disease, and combined presence of wild alleles of rs12610990 and rs8113319 could influence disease susceptibility. Furthermore, a strong linkage disequilibrium was also observed between the SNPs. Further studies are underway to validate galectin-4 and its genetic variants as blood-based biomarkers in early disease diagnosis, improving treatment outcome.

Single-cell Profiling Uncovers a Muc4-Expressing Metaplastic Gastric Cell Type Sustained by Helicobacter pylori-driven Inflammation

Mechanisms for Helicobacter pylori (Hp)-driven stomach cancer are not fully understood. In a transgenic mouse model of gastric preneoplasia, concomitant Hp infection and induction of constitutively active KRAS (Hp+KRAS+) alters metaplasia phenotypes and elicits greater inflammation than either perturbation alone. Gastric single-cell RNA sequencing showed that Hp+KRAS+ mice had a large population of metaplastic pit cells that expressed the intestinal mucin Muc4 and the growth factor amphiregulin. Flow cytometry and IHC-based immune profiling revealed that metaplastic pit cells were associated with macrophage and T-cell inflammation. Accordingly, expansion of metaplastic pit cells was prevented by gastric immunosuppression and reversed by antibiotic eradication of Hp. Finally, MUC4 expression was significantly associated with proliferation in human gastric cancer samples. These studies identify an Hp-associated metaplastic pit cell lineage, also found in human gastric cancer tissues, whose expansion is driven by Hp-dependent inflammation.

Significance

Using a mouse model, we have delineated metaplastic pit cells as a precancerous cell type whose expansion requires Hp-driven inflammation. In humans, metaplastic pit cells show enhanced proliferation as well as enrichment in precancer and early cancer tissues, highlighting an early step in the gastric metaplasia to cancer cascade.

Evaluation of the Effectiveness of Helicobacter pylori Eradication Regimens in Lithuania during the Years 2013-2020: Data from the European Registry on Helicobacter pylori Management (Hp-EuReg)

Background and Objectives: The prevalence of H. pylori in Eastern Europe remains quite high; however, there is insufficient data on the eradication regimens and their effectiveness. Therefore, the objective of the study was to evaluate the diagnostic methods and treatment of H. pylori infection as well as their adherence to Maastricht V/Florence consensus during the years 2013–2020 in Lithuania. Materials and Methods: Sub-study of the “European Registry on H. pylori Management” (Hp-EuReg), international multicenter prospective non-interventional registry of the routine clinical practice. Lithuanian data from the years 2013–2020 were analyzed for effectiveness on a modified intention-to-treat (mITT) basis. 2000 adult patients, diagnosed with H. pylori infection, were included. Data were compared to the European Maastricht V guidelines. Results: Triple-therapy was used in 90% of the cases. In 91% of the first-line prescriptions, standard triple therapy (STT) was used. The most common second-line treatment was a combination of PPI, amoxicillin and levofloxacin (PPI+A+L) (47%). The overall effectiveness in 552 cases valid for analysis was 90% by mITT. In first-line treatment, the STT effectiveness was 90% and second-line treatment with PPI+A+L achieved 92% by mITT. Increasing overall H. pylori eradication rates were observed: from 72% in 2013 to more than 90% in 2018–2020, as well as a shift from 7 to 10–14 days treatments duration throughout 2013–2020. Conclusions: In Lithuania, the prescribed eradication regimens for H. pylori were in accordance with the international guidelines but diagnostic methods and treatment duration only partially met Maastricht V/Florence guidelines. The eradication effectiveness was improved progressively during the years 2018–2020, reaching ≥90% cure rates.

Molecular Alterations in Gastric Intestinal Metaplasia

Gastric cancer (GC) remains one of the most common causes of mortality worldwide. Intestinal metaplasia (IM) is one of the preneoplastic gastric lesions and is considered an essential predisposing factor in GC development. Here we present a review of recent most relevant papers to summarize major findings on the molecular alterations in gastric IM. The latest progress in novel diagnostic methods allows scientists to identify various types of molecular alterations in IM, such as polymorphisms in various genes, changes in the expression of micro-RNAs and long noncoding RNAs, and altered microbiome profiles. The results have shown that some of these alterations have strong associations with IM and a potential to be used for screening, treatment, and prognostic purposes; however, one of the most important limiting factors is the inhomogeneity of the studies. Therefore, further large-scale studies and clinical trials with standardized methods designed by multicenter consortiums are needed. As of today, various molecular alterations in IM could become a part of personalized medicine in the near future, which would help us deliver a personalized approach for each patient and identify those at risk of progression to GC.

Helicobacter pylori Infection and the Patterns of Gastric Mucin Expression in Children

Background: The updated model for the mechanism of gastric carcinogenesis demonstrates that Helicobacter pylori (H. pylori) is a risk factor in every step of the process. The expression of certain gastric mucins is altered by H. pylori infection in adult patients. The aim of our research was to assess the impact of H. pylori infection on the expression of secretory mucins in the pediatric antral mucosa. Methods: Slides were stained with monoclonal antibodies for MUC5AC, MUC6 and MUC2, digitalized and scored using both a semiquantitative and a quantitative approach. Results: The expression of MUC5AC was significantly lower in infected children. Also, MUC2 expression was more pronounced in infected children. MUC6 expression did not differentiate between infected and noninfected children. Additionally, the presence of chronic inflammation significantly altered the expression of MUC6 and MUC2. The expression of MUC6 was significantly higher in patients with gastric atrophy. Conclusion: The minor differences in mucin expression at distinct ages might stem from different H. pylori exposure periods. Further research is needed to determine the particular patterns of expression according to age and to evaluate the effects of the interaction between H. pylori and mucins in the progression of the gastric carcinogenesis cascade.

Machine Learning Identifies Robust Matrisome Markers and Regulatory Mechanisms in Cancer

The expression and regulation of matrisome genes-the ensemble of extracellular matrix, ECM, ECM-associated proteins and regulators as well as cytokines, chemokines and growth factors-is of paramount importance for many biological processes and signals within the tumor microenvironment. The availability of large and diverse multi-omics data enables mapping and understanding of the regulatory circuitry governing the tumor matrisome to an unprecedented level, though such a volume of information requires robust approaches to data analysis and integration. In this study, we show that combining Pan-Cancer expression data from The Cancer Genome Atlas (TCGA) with genomics, epigenomics and microenvironmental features from TCGA and other sources enables the identification of "landmark" matrisome genes and machine learning-based reconstruction of their regulatory networks in 74 clinical and molecular subtypes of human cancers and approx. 6700 patients. These results, enriched for prognostic genes and cross-validated markers at the protein level, unravel the role of genetic and epigenetic programs in governing the tumor matrisome and allow the prioritization of tumor-specific matrisome genes (and their regulators) for the development of novel therapeutic approaches.

Immunoaffinity enrichment LC-MS/MS quantitation of CDH17 in tissues

Aim: There is little information in the literature regarding assays for measuring CDH17 in tissues. Numerous studies indicate overexpression of CDH17 in a variety of diseases including hepatocellular carcinoma, colorectal and gastric cancer. Here we present an immunoaffinity enrichment LC-MS/MS approach for analysis of CDH17 in human tissues, plasma and serum as well as preclinical models. Results: CDH17 levels were measured in colon and ileum tissues from healthy donors and inflamed tissues from patients with Ulcerative Colitus or Crohn's disease. Applicability of the immunocapture LC-MS/MS approach is demonstrated for colon tissues from non-diseased mouse and cynomolgus monkey. Conclusion: The analytical approaches discussed here are suitable for quantitation of CDH17 in various tissues to enable both preclinical and clinical assessment.

Long Noncoding RNA CAT104 Promotes Cell Viability, Migration, and Invasion in Gastric Carcinoma Cells Through Activation of MicroRNA-381-Inhibiting Zinc Finger E-box-Binding Homeobox 1 (ZEB1) Expression

Gastric carcinoma (GC) remains the second leading cause of cancer-related deaths worldwide. Good biomarkers are of paramount importance for GC therapy. This study aimed to assess the role of long noncoding RNA (lncRNA) CAT104 in GC. We found that CAT104 was highly expressed in human GC NCI-N87, SGC7901, BGC823, BGC803, and AGS cells. Suppression of CAT104 decreased NCI-N87 cell viability, migration, and invasion, but promoted apoptosis. CAT104 knockdown enhanced the expression of microRNA-381 (miR-381) expression in NCI-N87 cells. miR-381 participated in the regulatory effects of CAT104 on NCI-N87 cell viability, migration, invasion, and apoptosis. Zinc finger E-box-binding homeobox 1 (ZEB1) was identified as a direct target of miR-381. Overexpression of ZEB1 reversed the miR-381 mimic-induced cell viability, migration, and invasion inhibition. Suppression of ZEB1 reversed the miR-381 inhibitor-induced activation of the c-Jun N-terminal kinase (JNK) pathway and Wnt/β-catenin signaling pathways in NCI-N87 cells. In conclusion, CAT104 might function as an oncogenic factor in GC cells via regulating the expression of miR-381 and ZEB1.

Plasma olfactomedin 4 level in peripheral blood and its association with clinical features of breast cancer

The present study aimed to investigate the expression of olfactomedin 4 (OLFM4) in plasma of patients with breast cancer and its association with diagnosis, metastasis and prognosis of breast cancer. OLFM4 gene expression level of peripheral blood plasma in 60 patients with breast cancer and 26 healthy donors was examined by ELISA. The expression of OLFM4 in tumor tissues of patients with breast cancer was evaluated by immunohistochemistry (protein expression) and reverse transcription-quantitative polymerase chain reaction (mRNA expression), respectively. Circulating tumor cells (CTCs) were detected in a certain set of patients. The expression of OLFM4 in plasma of the overall healthy people was higher compared with patients with breast cancer. The plasma OLFM4 level in patients with breast cancer was consistent with the expression of OLFM4 protein in tumor tissues (R²=1), indicating that the level of plasma OLFM4 expression may represent the expression of OLFM4 in breast cancer tissues. The plasma OLFM4 level in patients with histological grade I was significantly lower compared with grade III (P<0.05). Breast cancer patients with positive CTC were associated with low level of plasma OLFM4. These results suggest that low OLFM4 expression in plasma or tissue specimens of breast cancer patients is more likely to represent low histological differentiation and decreased invasive/metastatic capabilities. Taken together, plasma OLFM4 level may be considered as a biomarker for diagnosis and prognosis of breast cancer for cases where there are difficulties in obtaining tumor tissue samples.

Differential expression of two genes Oct-4 and MUC5AC associates with poor outcome in patients with gastric cancer

Gastric cancer (GC) is the most frequent leading cause of cancer-associated mortality worldwide that is linked to poor prognosis due to the lack of appropriate biomarkers. Our aim was to evaluate the MUC5AC and Oct-4 expression levels in GC and to assess their association with clinical factors. Immunohistochemical analysis (IHC) and qRT-PCR were performed in GC patients to examine the MUC5AC and Oct-4 expression levels. The mRNA level of MUC5AC was significantly decreased in tumour tissues compared with non-cancerous tissues (1.11 ± 0.69 vs 3.7 ± 0.71; P = .024). On the other hand, Oct-4 mRNA level was upregulated in tumour tissues as compared to normal tissues (2. 86 ± 0.78 vs 0.87 ± 0.54; P = .0015). Decreased expression of MUC5AC was detected in 27 patients (67.5%), while high to moderate expression levels were observed in 13 cases (32.5%), but in normal tissues the expression levels of MUC5AC were increased (P = .001). The decreased expression of MUC5AC was associated with aggressive tumour characteristics, such as TNM stage (P = .023), histologic type (P = .012) and lymph node metastasis (P = .001). High expression of Oct-4 was detected in 24 tumour tissues (60%), while 16 cases (40%) showed low expression level. Increased Oct-4 expression was correlated with clinicopathological characteristics such TNM stage (P = .002), histologic type (P = .008) and lymph node metastasis (P = .001). Our results showed that high Oct-4 expression and the reduction of MUC5AC expression may be involved in the progression and an unfavorable prognosis of GC.

Lymph Node Metastasis in Mucosal Gastric Cancer: Reappraisal of Expanded Indication of Endoscopic Submucosal Dissection

OBJECTIVE

To evaluate risk factors for lymph node (LN) metastasis in mucosal gastric cancer, particularly the effect of cellular differentiation, and implications for the indication of endoscopic submucosal dissection (ESD).

SUMMARY BACKGROUND DATA

The indication of ESD has been expanded to undifferentiated-type (UD-type) gastric cancer despite risk of LN metastasis.

METHODS

Patients who underwent radical gastrectomy for pT1a stage primary gastric adenocarcinoma between 2008 and 2012 were retrospectively analyzed. We evaluated risk factors of LN metastasis using univariate and multivariate analyses. Pathologic slides of primary tumor and metastatic LNs from LN positive patients were reviewed.

RESULTS

A total of 1003 mucosal gastric cancer patients were enrolled, and mean number of retrieved LNs was 35.5. Eighteen (1.8%) among them had LN metastasis: 2 of the 502 differentiated-type (D-type) patients and 16 of the 501 UD-type patients (0.4% vs 3.2%, P < 0.001). Type of cellular differentiation was a significant risk factor for LN metastasis in univariate and multivariate analyses. Of 216 UD-type patients satisfying the expanded indication of ESD, 5 patients (2.3%) showed LN metastasis. Despite more aggressive clinical features such as larger size of tumor and more LN metastasis, the UD-type cancer showed a less invasion into the muscularis mucosae layer than the D-type cancer.

CONCLUSIONS

Because UD-type cancer is a risk factor for LN metastasis in mucosal gastric cancer, ESD cannot be concluded to be a better option than surgery in all UD-type cancer patients. Redefinition of the expanded indication of ESD is required.

Epigenetic silencing of olfactomedin-4 enhances gastric cancer cell invasion via activation of focal adhesion kinase signaling

Downregulation of olfactomedin-4 (OLFM4) is associated with tumor progression, lymph node invasion and metastases. However, whether or not downregulation of OLFM4 is associated with epigenetic silencing remains unknown. In this study, we investigate the role of OLFM4 in gastric cancer cell invasion. We confirm the previous result that OLFM4 expression is increased in gastric cancer tissues and decreases with an increasing number of metastatic lymph nodes, which are associated with OLFM4 promoter hypermethylation. Overexpression of OLFM4 in gastric cancer cells had an inhibitory effect on cell invasion. Furthermore, we found that focal adhesion kinase (FAK) was negatively correlated with OLFM4 in regards to lymph node metastasis in gastric cancer tissues. Also, inhibition of FAK induced by OLFM4 knockdown resulted in a decrease in cell invasion. Thus, our study demonstrates that epigenetic silencing of OLFM4 enhances gastric cancer cell invasion via activation of FAK signaling. [BMB Reports 2015; 48(11): 630-635]

Correlation of cadherin-17 protein expression with clinicopathological features and prognosis of patients with sporadic gastric cancer

This study aimed to explore the correlations between cadherin-17 (CDH17) protein expression and the clinicopathological features and prognosis of patients with sporadic gastric cancer (GC). Nine relevant studies of 1,960 patients were identified using electronic database searches supplemented with a manual search in strict accordance with inclusion and exclusion criteria. Statistical analyses were conducted using STATA 12.0 statistical software. Relative risks and 95% confidence intervals were determined, and Z test was used to measure the significance of the overall effect size. A total of nine eligible cohort studies were included in this meta-analysis. The expression of CDH17 in patients with diffuse GC was significantly higher than in those with intestinal-type GC. Moreover, the tumor depth of invasion differed significantly between patients with positive CDH17 (CDH17+) and negative CDH17 (CDH17-) GC. However, there were no significant differences between CDH17+ and CDH17- GC patients with respect to tumor node metastasis clinical stages, histological grades, or lymph node metastasis. Despite the differences in invasive depth, there was no significant difference in 5-year survival rates between CDH17+ and CDH17- GC patients. Our meta-analysis provides evidence that CDH17 protein expression may be associated with the development of GC, suggesting that CDH17 is an important biomarker that could be useful for the early diagnosis of GC. However, CDH17 levels do not appear to impact overall survival.

Prognostic value of Muc5AC in gastric cancer: A meta-analysis

AIM: To assess the correlation between decreased Muc5AC expression and patients’ survival and clinicopathological characteristics by conducting a meta-analysis.

METHODS: Literature searches were performed in PubMed and EMBASE, and 11 studies met our criteria. Summary hazard ratios or odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to estimate the effect. For the pooled analysis of the correlation between decreased Muc5AC expression and clinicopathological characteristics (tumour invasion depth, lymph node metastasis, tumour-node-metastasis stage, tumour size, venous invasion and lymphatic invasion), ORs and their variance were combined to estimate the effect.

RESULTS: Eleven retrospective cohort studies comprising 2135 patients were included to assess the association between Muc5AC expression and overall survival and/or clinicopathological characteristics. Decreased Muc5AC expression was significantly correlated with poor overall survival of gastric cancer patients (pooled HR = 1.35, 95%CI: 1.08-1.7). Moreover, decreased Muc5AC expression was also significantly associated with tumour invasion depth (pooled OR = 2.12, 95%CI: 1.56-2.87) and lymph node metastasis (pooled OR = 1.56, 95%CI: 1.00-2.44) in gastric cancer.

CONCLUSION: Decreased Muc5AC expression might be a poor prognostic predictor for gastric cancer.

Olfactomedin-related proteins 4 (OLFM4) expression is involved in early gastric carcinogenesis and of prognostic significance in advanced gastric cancer

Olfactomedin 4 (OLFM4) has been demonstrated to be upregulated in various cancers and involved in many cellular processes such as cell adhesion, apoptosis, and cell proliferation. In gastric cancer, clinicopathological relevance of OLFM4 expression has been reported. However, there are few studies showing how expression of OLFM4 evolves during multistep gastric carcinogenesis. In this study, we investigated OLFM4 expression during gastric carcinogenesis using RNA in situ hybridization (ISH). We found that OLFM4 expression is absent in normal gastric mucosa, begins to appear at the isthmus region in gastric glands in chronic gastritis, and is remarkably increased in intestinal metaplasia (IM). Interestingly, gastric-type glands around IM frequently expressed OLFM4 before CDX2 was expressed, suggesting that OLFM4 might be involved in regulating CDX2 expression. However, overexpression of OLFM4 failed to induce CDX2 transcription. All gastric adenomas were strongly positive for OLFM4. OLFM4 expression was higher in intestinal type, well to moderately differentiated and early-stage adenocarcinomas, and decreased in poorly differentiated and advanced-stage gastric cancer (GC). Although OLFM4 expression had no prognostic value for GC overall (P = 0.441), it was associated with poor survival of GC in stage II, III, and IV (P = 0.018), suggesting that OLFM4 expression has prognostic significance for late-stage GC. Our findings suggest that OLFM4 is not only involved in early stages of gastric carcinogenesis but also a useful prognostic marker for advanced GC, which is encouraging for further studies exploring OLFM4 as a potential target for therapy of GC.

Overexpression of Plasminogen Activator Inhibitor-1 in Advanced Gastric Cancer with Aggressive Lymph Node Metastasis

Purpose

The purpose of this study is to investigate differentially expressed genes using DNA microarray between advanced gastric cancer (AGC) with aggressive lymph node (LN) metastasis and that with a more advanced tumor stage but without LN metastasis.

Materials and Methods

Five sample pairs of gastric cancer tissue and normal gastric mucosa were taken from three patients with T3N3 stage (highN) and two with T4N0 stage (lowN). Data from triplicate DNA microarray experiments were analyzed, and candidate genes were identified using a volcano plot that showed ≥ 2-fold differential expression and were significant by Welch's t test (p < 0.05) between highN and lowN. Those selected genes were validated independently by reverse-transcriptase–polymerase chain reaction (RT-PCR) using five AGC patients, and tissue-microarray (TMA) comprising 47 AGC patients.

Results

CFTR, LAMC2, SERPINE2, F2R, MMP7, FN1, TIMP1, plasminogen activator inhibitor-1 (PAI-1), ITGB8, SDS, and TMPRSS4 were commonly up-regulated over 2-fold in highN. REG3A, CD24, ITLN1, and WBP5 were commonly down-regulated over 2-fold in lowN. Among these genes, overexpression of PAI-1 was validated by RT-PCR, and TMA showed 16.7% (7/42) PAI-1 expression in T3N3, but none (0/5) in T4N0 (p=0.393).

Conclusion

DNA microarray analysis and validation by RT-PCR and TMA showed that overexpression of PAI-1 is related to aggressive LN metastasis in AGC.

Olfactomedin-4 is a candidate biomarker of solid gastric, colorectal, pancreatic, head and neck, and prostate cancers

Olfactomedin-4 (OLFM4, OLM4) is a 72 kDa secreted glycoprotein belonging to the olfactomedin family. The OLFM4 gene expression is regulated by the transcription factors NF-kappa B and AP-1, and the OLM4 functions are poorly understood. OLM4 has been described as being able to interact with cell surface proteins such as lectins and concanavalin-A suggesting that one function of OLM4 is to regulate cell adhesion and migration. OLM4 is a marker for intestinal stem cells and is expressed at the bottom of the intestinal crypts. Expression of OLM4 during tumor development showed that OLM4 expression is increased in the early stages of tumor initiation. As OLM4 is a secreted protein, it is a prime candidate for biomarker research for tumor detection or progression. Levels of circulating OLM4 were significantly higher in patients with gastric, colorectal, and pancreatic cancers than in healthy subjects.

Upregulation of autophagy-related gene-5 (ATG-5) is associated with chemoresistance in human gastric cancer

Autophagy-related gene-5 (ATG-5) is one of the key regulators of autophagic cell death. It has been widely regarded as a protective molecular mechanism for tumor cells during the course of chemotherapy. In the present study, we investigated the expression pattern of ATG-5 and multidrug resistance-associated protein-1 (MRP-1) in 135 gastric cancers (GC) patients who were treated with epirubicin, cisplatin and 5-FU adjuvant chemotherapy (ECF) following surgical resection and explored their potential clinical significance. We found that both ATG-5 (77.78%) and MRP-1 (79.26%) were highly expressed in GC patients. ATG-5 expression was significantly associated with depth of wall invasion, TNM stages and distant metastasis of GC (P<0.05), whereas MRP-1 expression was significantly linked with tumor size, depth of wall invasion, lymph node metastasis, TNM stages and differentiation status (P<0.05). ATG-5 expression was positively correlated with MRP-1 (rp = 0.616, P<0.01). Increased expression of ATG-5 and MPR-1 was significantly correlated with poor overall survival (OS; P<0.01) and disease free survival (DFS; P<0.01) of our GC cohort. Furthermore, we demonstrated that ATG-5 was involved in drug resistant of GC cells, which was mainly through regulating autophagy. Our data suggest that upregulated expression of ATG-5, an important molecular feature of protective autophagy, is associated with chemoresistance in GC. Expression of ATG-5 and MRP-1 may be independent prognostic markers for GC treatment.

The changes in MUC5AC expression in gastric cancer before and after Helicobacter pylori eradication

PURPOSE

To investigate MUC5AC expression in gastric cancer before and after Hp eradication.

METHODS

The MUC5AC protein and mRNA were detected in gastric cancer tissue by western blot and real time PCR protocols before and after Hp eradication (Hp positive group). Gastric cancer tissue without Hp infection served as the control group (Hp negative group).

RESULTS

The MUC5AC protein and mRNA expression was more significantly increased in gastric cancer after Hp eradication as compared to that before Hp eradication, but it was significantly lower than of the control group. The relative amount of MUC5AC in the well-differentiated cancer was higher than that of the moderately or poorly-differentiated cancer, in either Hp positive or control groups. The relative amount of MUC5AC in cancer tissues with more than five metastatic lymph nodes was significantly lower than that of the cancer tissues with five or less metastatic lymph nodes, and was significantly lower in the Hp positive group as compared to that of the control group.

CONCLUSIONS

The reduction of the MUC5AC might be related to gastric carcinogenesis caused by Hp and the progression of gastric cancer.

Two-dimensional gel electrophoresis of gastric tissue in an alkaline pH range

2DE in combination with MS has facilitated the discovery of several proteins with altered abundance in gastric cancer. While acidic and wide pH ranges have been widely investigated, analysis in the alkaline pH range has not been specifically performed in gastric cancer to date. In the present study, we initially optimized the 2DE in alkaline pH range (pH 7-11) for gastric tissue samples. Using a modified lysis buffer, we analyzed pooled nontumor and tumor samples for proteins with altered abundance in gastric adenocarcinoma. We successfully identified 38 silver-stained spots as 24 different proteins. Four of these were chosen for investigation with immunoblotting on individual paired samples to determine whether the changes seen in 2DE represent the overall abundance of the protein or possibly only a single form. While mitochondrial trifunctional protein (MTP) subunits were decreased in 2DE gels, immunoblotting identified their overall abundance as being differently dysregulated: in the gastric tumor samples, the MTP-α subunit was decreased, and the MTP-β subunit was increased. On the other hand, heterogenous nuclear ribonucleoprotein M and galectin-4 were increased in the gastric tumor samples in both 2DE and immunoblotting.

Reg proteins and their roles in inflammation and cancer of the human digestive system

The regenerating gene (Reg) family is a group of small molecules that includes four members found in various species, although only three are found in human tissues. Their expression is stimulated by certain growth factors or cytokines. The Reg family plays different roles in proliferation, migration, and anti-apoptosis through activating different signaling pathways. Their dysexpression is closely associated with a number of human conditions and diseases such as inflammation and cancer, especially in the human digestive system. Clinically, upregulation of Reg proteins is usually demonstrated in histological sections and sera from cancer patients. Therefore, Reg proteins can predict the progression and prognosis of cancers, especially those of the digestive tract, and can also act as diagnostic markers and therapeutic targets.

Gene expression analysis of a Helicobacter pylori-infected and high-salt diet-treated mouse gastric tumor model: identification of CD177 as a novel prognostic factor in patients with gastric cancer

BACKGROUND

Helicobacter pylori (H. pylori) infection and excessive salt intake are known as important risk factors for stomach cancer in humans. However, interactions of these two factors with gene expression profiles during gastric carcinogenesis remain unclear. In the present study, we investigated the global gene expression associated with stomach carcinogenesis and prognosis of human gastric cancer using a mouse model.

METHODS

To find candidate genes involved in stomach carcinogenesis, we firstly constructed a carcinogen-induced mouse gastric tumor model combined with H. pylori infection and high-salt diet. C57BL/6J mice were given N-methyl-N-nitrosourea in their drinking water and sacrificed after 40 weeks. Animals of a combination group were inoculated with H. pylori and fed a high-salt diet. Gene expression profiles in glandular stomach of the mice were investigated by oligonucleotide microarray. Second, we examined an availability of the candidate gene as prognostic factor for human patients. Immunohistochemical analysis of CD177, one of the up-regulated genes, was performed in human advanced gastric cancer specimens to evaluate the association with prognosis.

RESULTS

The multiplicity of gastric tumor in carcinogen-treated mice was significantly increased by combination of H. pylori infection and high-salt diet. In the microarray analysis, 35 and 31 more than two-fold up-regulated and down-regulated genes, respectively, were detected in the H. pylori-infection and high-salt diet combined group compared with the other groups. Quantitative RT-PCR confirmed significant over-expression of two candidate genes including Cd177 and Reg3g. On immunohistochemical analysis of CD177 in human advanced gastric cancer specimens, over-expression was evident in 33 (60.0%) of 55 cases, significantly correlating with a favorable prognosis (P = 0.0294). Multivariate analysis including clinicopathological factors as covariates revealed high expression of CD177 to be an independent prognostic factor for overall survival.

CONCLUSIONS

These results suggest that our mouse model combined with H. pylori infection and high-salt diet is useful for gene expression profiling in gastric carcinogenesis, providing evidence that CD177 is a novel prognostic factor for stomach cancer. This is the first report showing a prognostic correlation between CD177 expression and solid tumor behavior.

Effects of Helicobacter pylori infection on MUC5AC protein expression in gastric cancer

AIM

To investigate the effects of the expression of the MUC5AC protein in gastric cancer depending on the Helicobacter pylori (Hp) infection status.

MATERIALS & METHODS

The MUC5AC protein and mRNA were detected using western blot and real-time PCR protocols in gastric cancer tissue and stratified for Hp infection. Gastric mucus membranes near the cancer site serve as the control group.

RESULTS

The expression of MUC5AC protein and mRNA is significantly decreased in gastric cancer tissue (p < 0.05). The decrease was more significant in the Hp-infected group than in the Hp-uninfected group (p < 0.05).

CONCLUSION

The infection of Hp is correlated with a decrease in MUC5AC protein amount in gastric cancer tissue. The current result suggests that there may be a potential necessary link between Hp, MUC5AC and gastric cancer.

Up-regulation of cadherin 17 and down-regulation of homeodomain protein CDX2 correlate with tumor progression and unfavorable prognosis in epithelial ovarian cancer

OBJECTIVE

Cadherin 17 (CDH17), belonging to the 7D-cadherin superfamily, represents a novel oncogene, which is involved in tumor invasion and metastasis. Its expression has been demonstrated to be regulated by caudal-related homeobox transcription factor CDX2. The roles of 2 biomarkers have been conflictingly explained. Therefore, the aims of this study were to investigate the expression patterns of CDH17 and CDX2 in human epithelial ovarian cancer (EOC) and to evaluate the clinical significance of these 2 markers in the progression and prognosis of EOC.

METHODS

CDH17 and CDX2 expressions in 182 paraffin-embedded EOC specimens were detected by immunohistochemical staining. Associations of their expression with clinical pathological factors and overall survival were statistically evaluated.

RESULTS

Compared with normal surface ovarian epithelium tissues, CDH17 expression was upregulated and CDX2 expression was downregulated in EOC tissues. There was a negative correlation between CDH17 and CDX2 expression in EOC tissues (r = -0.76, P = 0.001). Tumors with high CDH17 expression were more likely to have advanced stage (P = 0.01) and higher grade (P = 0.03). Patients with low CDX2 expression were more frequently to be at the advanced stage of disease (P = 0.01). In addition, univariate analysis indicated that the patients with high CDH17 expression correlated with poor prognosis in patients with EOC (P = 0.001), as opposed to CDX2 (P = 0.003). Especially, the survival rate of patients with EOC with CDH17-high/CDX2-low expression was the lowest (P < 0.001). Multivariate statistical analysis showed that the conjoined expression of CDH17/CDX2 was an independent prognostic indicator of EOC (P = 0.01).

CONCLUSIONS

Our data suggest that both the up-regulation of CDH17 and the down-regulation of CDX2 may be associated with the advanced stage of EOC. A conjoined detection of CDH17/CDX2 expression may be associated with unfavorable prognosis in patients with this disease.

Cadherin-17 induces tumorigenesis and lymphatic metastasis in gastric cancer through activation of NFκB signaling pathway

Cadherin-17 (CDH17), as a structurally unique member of the cadherin superfamily, has been identified to predict a poor prognosis for gastric cancer (GC). Our previous study demonstrated the positive correlation between CDH17 and lymph node micrometastasis in GC. We sought to further identify the role of CDH17 in the tumorigenesis and lymphatic metastasis of GC. Hence, we inhibited the CDH17 expression in MKN-45 gastric cancer cells by using RNA interference. Consequently, the malignant potency of cancer cells was evaluated, and the change in NFκB signaling pathway was also probed. Tumor growth and lymphatic metastasis model were conducted in nude mice to confirm the hypothesis. Downregulation of CDH17 not only suppressed the proliferation, adherence and invasion potency of MKN-45 cells, but also induced cell cycle arrest. Meanwhile, the NFκB signaling pathway was inactivated as well, with the reductions of downstream proteins including VEGF-C and MMP-9. Moreover, silencing CDH17 inhibited tumor growth in vivo significantly, and there was no lymph node metastasis detected in the mice without CDH17 expression, as opposed to the positive nodes found in controls. CDH17 is a novel oncogene in gastric cancer cells, which is associated with lymphatic metastasis and proliferation strongly. The inactivation of NFκB signaling pathway might be involved in targeting CDH17 in GC. On the whole, CDH17 is proposed to serve as a biomarker and attractive therapeutic target in GC.

Single nucleotide polymorphisms in the CDH17 gene of colorectal carcinoma

AIM: To investigate the relationship between c.343A>G and c.2216A>C polymorphism sites in the CDH17 gene and colorectal carcinoma.

METHODS: Ninety-three non-consanguineous colorectal carcinoma patients admitted to the Department of Oncology at the First Affiliated Hospital of Zhengzhou University were included in this study. Ninety-three peripheral venous blood samples, of approximately one milliliter from each patient, were collected between December 2009 and August 2010. The genomic DNA of these peripheral venous blood samples were extracted and purified using a Fermentas Genomic DNA Purification Kit (Fermentas, CA) according to the manufacturer’s protocol. The single nucleotide polymorphisms (SNPs) of the liver-intestine cadherin (CDH17) gene c.343A>G and c.2216A>C were determined by the polymerase chain reaction-single strand conformation polymorphism method (PCR-SSCP) in 93 peripheral venous blood samples from patients suffering with colorectal carcinoma. Typical samples that showed different migration bands in SSCP were confirmed by sequencing. Directed DNA sequencing was used to check the correctness of the genotype results from the PCR-SSCP method.

RESULTS: There was a significant association between the c.2216 A>C SNPs of the CDH17 gene and the tumor-node-metastasis (TNM) grade, as well as with lymph node status, in 93 peripheral venous blood samples from colorectal carcinoma patients. The genotype frequencies of A/C, A/A, and C/C were 12.90%, 33.33% and 53.76%, respectively. There was a significant correlation between lymph node metastasis, TNM grade, and the genotype distribution (P < 0.05). The C/C genotype raised the risk of lymph node metastasis and the TNM grade. There was a significant difference in the TNM grade and lymph node metastasis between the A/A and C/C genotypes (P = 0.003 and P = 0.013, respectively). Patients with colorectal carcinoma carrying the C allele tended to have a higher risk of lymph node metastasis and have a higher TNM grade. The difference between the TNM grades, as well as the lymph node metastasis of the two alleles, was statistically significant (P < 0.01).

CONCLUSION: The SNPs of the CDH17 gene c.2216 A>C might be clinically important in the prognosis of colorectal carcinoma.

Proteomic profiling of paraffin-embedded samples identifies metaplasia-specific and early-stage gastric cancer biomarkers

Early diagnosis and curative resection are the predominant factors associated with increased survival in patients with gastric cancer. However, most gastric cancer cases are still diagnosed at later stages. Since most pathologic specimens are archived as FFPE samples, the ability to use them to generate expression profiles can greatly improve cancer biomarker discovery. We sought to uncover new biomarkers for stomach preneoplastic metaplasias and neoplastic lesions by generating proteome profiles using FFPE samples. We combined peptide isoelectric focusing and liquid chromatography-tandem mass spectrometry analysis to generate proteomic profiles from FFPE samples of intestinal-type gastric cancer, metaplasia, and normal mucosa. The expression patterns of selected proteins were analyzed by immunostaining first in single tissue sections from normal stomach, metaplasia, and gastric cancer and later in larger tissue array cohorts. We detected 60 proteins up-regulated and 87 proteins down-regulated during the progression from normal mucosa to metaplasia to gastric cancer. Two of the up-regulated proteins, LTF and DMBT1, were validated as specific markers for spasmolytic polypeptide-expressing metaplasia and intestinal metaplasia, respectively. In cancers, significantly lower levels of DMBT1 or LTF correlated with more advanced disease and worse prognosis. Thus, proteomic profiling using FFPE samples has led to the identification of two novel markers for stomach metaplasias and gastric cancer prognosis.

Methylation-dependent activation of CDX1 through NF-κB: a link from inflammation to intestinal metaplasia in the human stomach

The caudal homeobox factor 1 (CDX1) is an essential transcription factor for intestinal differentiation. Its aberrant expression in intestinal metaplasia of the upper gastrointestinal tract is a hallmark within the gastritis-metaplasia-carcinoma sequence. CDX1 expression is influenced by certain pathways, such as Wnt, Ras, or NF-κB signaling; however, these pathways alone cannot explain the transient expression of CDX1 in intestinal metaplasia or the molecular inactivation mechanism of its loss in cases of advanced gastric cancer. In this study, we investigated the epigenetic inactivation of CDX1 by promoter methylation, as well as the functional link of CDX1 promoter methylation to the inflammatory NF-κB signaling pathway. We identified methylation-dependent NF-κB binding to the CDX1 promoter and quantified it using competitive electrophoretic mobility shift assays and chromatin immunoprecipitation. A methylated CDX1 promoter was associated with closed chromatin structure, reduced NF-κB binding, and transcriptional silencing. Along the gastritis-metaplasia-carcinoma sequence, we observed a biphasic pattern of tumor necrosis factor-α (TNF-α) protein expression and an inverse biphasic pattern of CDX1 promoter methylation; both are highly consistent with CDX1 protein expression. The stages of hyper-, hypo-, and hyper-methylation patterns of the CDX1 promoter were inversely correlated with the NF-κB signaling activity along this sequence. In conclusion, these functionally interacting events drive CDX1 expression and contribute to intestinal metaplasia, epithelial dedifferentiation, and carcinogenesis in the human stomach.