The expression of E-cadherin-catenin complex in patients with advanced gastric cancer: role in formation of metastasis

Reduced expression of E-cadherin correlates with poor prognosis and unfavorable clinicopathological features in gastric carcinoma: a meta-analysis

BACKGROUNDS

Gastric carcinoma (GC) is one of the most fatal human malignancies globally, with a median survival time less than 1 year. E-cadherin exerts a crucial role in the development and progression of GC as an adhesive, invasive suppressor gene. Whether reduced E-cadherin has an impact on prognosis, clinicopathological features for GC has been well studied, but no conclusive results has been obtained.

METHODS

Eligible studies and relevant data were obtained from PubMed, Elsevier, Embase, Cochrane Library and Web of Science databases until June 30, 2023. A fixed- or random-effects model was used to calculate pooled odds ratios (OR) and 95% confidence intervals (CI). Correlation of E-cadherin expression with overall survival (OS), clinicopathological features and risk factors were evaluated.

RESULTS

36 studies fulfilled the selected criteria. 9048 cases were included. This meta-analysis showed that patients with GC with reduced E-cadherin had unfavourable clinicopathological features and poor OS. The pooled ORs of one-, three- and five-year OS were 0.38 (n = 25 studies, 95%CI: 0.25-0.57, Z = 4.61, P < 0.00001), 0.33 (n = 25 studies, 95% CI: 0.23-0.47, Z = 6.22, P < 0.00001), 0.27 (n = 22 studies, 95% CI: 0.18-0.41, Z = 6.23, P < 0.00001), respectively. Moreover, reduced E-cadherin expression significantly correlated with differentiation grade (OR = 0.29, 95% CI: 0.22-0.39, Z = 8.58, P < 0.00001), depth of invasion (OR = 0.49, 95% CI: 0.36-0.66, Z = 4.58, P < 0.00001), lymphatic node metastasis (OR = 0.49, 95% CI: 0.38-0.64, Z = 5.38, P < 0.00001), distant metastasis (OR = 2.24, 95% CI: 1.62-3.09, Z = 4.88, P < 0.00001), peritoneal metastasis (OR = 2.17, 95% CI: 1.39-3.39, Z = 3.40, P = 0.0007), TNM stage (OR = 0.41, 95% CI: 0.28-0.61, Z = 4.44, P < 0.00001), lymphatic vessel invasion (OR = 1.77, 95% CI: 1.11-2.82, Z = 2.39, P = 0.02), vascular invasion (OR = 1.55, 95% CI: 1.22-1.96, Z = 3.58, P = 0.0003), Lauren type (OR = 0.35, 95% CI: 0.21-0.57, Z = 4.14, P < 0.0001), Borrmann classification (OR = 0.50, 95% CI: 0.25-0.99, Z = 1.97, P = 0.048) and tumor size (≥5 cm vs. <5 cm: OR = 1.73, 95% CI: 1.34-2.23, Z = 4.19, P < 0.0001; ≥6 cm vs. <6 cm: OR = 2.29, 95% CI: 1.51-3.49, Z = 3.87, P = 0.0001). No significant association was observed between reduced E-cadherin expression and liver metastasis, perineural invasion, alcohol consumption, smoking status, familial history, Helicobacter pylori (HP) infection.

CONCLUSIONS

The reduced expression of E-cadherin is significantly correlated with poor OS and unfavourable clinicopathological features in GC. The expression level of E-cadherin not only serves as a predictor for disease progression and prognosis in GC but also emerges as a novel therapeutic target.

Signaling pathways and therapeutic interventions in gastric cancer

Gastric cancer (GC) ranks fifth in global cancer diagnosis and fourth in cancer-related death. Despite tremendous progress in diagnosis and therapeutic strategies and significant improvements in patient survival, the low malignancy stage is relatively asymptomatic and many GC cases are diagnosed at advanced stages, which leads to unsatisfactory prognosis and high recurrence rates. With the recent advances in genome analysis, biomarkers have been identified that have clinical importance for GC diagnosis, treatment, and prognosis. Modern molecular classifications have uncovered the vital roles that signaling pathways, including EGFR/HER2, p53, PI3K, immune checkpoint pathways, and cell adhesion signaling molecules, play in GC tumorigenesis, progression, metastasis, and therapeutic responsiveness. These biomarkers and molecular classifications open the way for more precise diagnoses and treatments for GC patients. Nevertheless, the relative significance, temporal activation, interaction with GC risk factors, and crosstalk between these signaling pathways in GC are not well understood. Here, we review the regulatory roles of signaling pathways in GC potential biomarkers, and therapeutic targets with an emphasis on recent discoveries. Current therapies, including signaling-based and immunotherapies exploited in the past decade, and the development of treatment for GC, particularly the challenges in developing precision medications, are discussed. These advances provide a direction for the integration of clinical, molecular, and genomic profiles to improve GC diagnosis and treatments.

HER-2 positivity is a high risk of recurrence of stage I gastric cancer

BACKGROUND/AIMS

The treatment of gastric cancer remains unsatisfactory. We aimed to investigate the prognostic value of immunohistochemical staining in gastric cancer.

METHODS

We analyzed 505 (279 early staged, 226 advanced-staged) gastric cancer tissues from patients who underwent radical gastric resection between January 2014 and December 2016. Available surgical specimens immunohistochemically stained for p53, epidermal growth factor receptor (EGFR), human EGFR 2 (HER-2), E-cadherin, and Ki-67 were reviewed. We evaluated the association between positivity to various biomarkers and disease recurrence, disease-free survival, lymph node metastasis, and microscopic lymphovascular invasion.

RESULTS

The median follow-up duration was 32.5 months (range, 7 to 70). Advanced gastric cancer cases showed high Ki-67 expression; other cases showed unremarkable expression. Concerning disease recurrence, lymphatic invasion, and disease-free interval, all biomarkers had no prognostic effects. HER-2-positive stage I gastric cancer tended to occur in old patients and in the upper one-third of the stomach (p = 0.01). HER-2 positivity was significantly correlated with disease recurrence (p = 0.01), lymphatic invasion (p = 0.03), and vascular invasion (p = 0.03) in stage I cases.

CONCLUSION

Only HER-2 was associated with the recurrence of stage I gastric cancer. HER-2-positive stage I gastric cancer requires additional therapy despite curative resection.

mRNA Expression Analysis of E-Cadherin, VEGF, and MMPs in Gastric Cancer: a Pilot Study

Gastric cancer (GC) is a serious fatal cancer on a global scale because of its presentation at advanced stage. The expressions of vascular endothelial growth factor (VEGF), E-cadherin, and matrix metalloproteinases (MMPs) in other cancers have been reported. However, its expression and underlying mechanisms are little known in gastric cancer in Indian context. In this study, we detected mRNA expression of VEGF, E-cadherin, and MMPs (MMP-1, MMP-2, and MMP-9) in 73 gastric cancer tissues and 27 normal controls by reverse-transcriptase polymerase chain reaction (RT-PCR). Receiver operator characteristics analysis was done for determining the diagnostic utility of VEGF, MMPs and E-cadherin with respect to the sensitivity and specificity. The association of VEGF, MMPs, and E-cadherin expression with the clinicopathological characteristics and the prognosis was subsequently analyzed. The mRNA expression results showed that E-cadherin was significantly downregulated in 47.9% of GC in comparison to control. There was no change in VEGF expression observed in 90.4% GC cases. MMP-1, MMP-2, and MMP-9 were overexpressed in 13.7%, 28.8%, and 11% of GC, respectively, with significant change in MMP-2 (p ≤ 0.0001) and MMP-9 (p = 0.027) in comparison to control. Our results strengthen the necessity of more studies to elucidate the prophetic role of these genes in the development of gastric cancer.

12-Lipoxygenase promotes invasion and metastasis of human gastric cancer cells via epithelial-mesenchymal transition

The role of 12-lipoxygenase (12-LOX) in tumorigenesis has been well established in several types of human cancer, including gastric cancer. It was reported that epithelial-mesenchymal transition (EMT) contributes to tumor invasion and metastasis. However, whether 12-LOX promotes the invasion and metastasis of human gastric cancer cells via EMT remains to be elucidated. In the present study, the expression of 12-LOX and EMT markers, N-cadherin and E-cadherin, was evaluated in gastric cancer and adjacent normal mucosa samples by immunohistochemical analysis. 12-LOX-overexpressing gastric cancer cells were established via lentiviral transfection of SCG-7901 cells. Wound-healing and Transwell assays were performed to examine the regulation of cell metastasis and invasion by 12-LOX. Furthermore, the regulation of N-cadherin expression by 12-LOX was evaluated using reverse transcription-quantitative polymerase chain reaction and western blotting. The results revealed that the expression of 12-LOX and N-cadherin was significantly higher in gastric cancer compared with that in adjacent normal mucosa tissues (P<0.05). By contrast, the expression of E-cadherin was significantly decreased in gastric cancer compared with that in adjacent normal mucosa tissues (P<0.05). Furthermore, the expression of 12-LOX was positively associated with N-cadherin expression in gastric cancer tissues. 12-LOX-overexpressing gastric cancer cells exhibited significantly increased invasion and migration abilities compared with the empty vector and control groups. The expression of N-cadherin in 12-LOX-overexpressing gastric cancer cells was increased compared with that in the empty vector and control groups. The present study suggests that EMT may be involved in the promotion of the invasion and metastasis of human gastric cancer cells by 12-LOX.

Epigenetic inactivation of FAT4 contributes to gastric field cancerization

BACKGROUND

Gastric cancer (GC) is highly influenced by aberrant methylation, and accumulation of aberrant methylation in gastric mucosae produces an epigenetic field for cancerization. Nevertheless, the individual driver genes involved in such field cancerization are still unclear. Here, we aimed to demonstrate that FAT4, a novel tumor suppressor identified by exome sequencing of GC, is methylation-silenced and that such methylation is involved in epigenetic field cancerization for GC.

METHODS

A transcription start site was determined by the 5' rapid amplification of complementary DNA ends method. DNA methylation was analyzed by bisulfite sequencing with use of a next-generation sequencer or quantitative methylation-specific PCR. Gene expression was analyzed by quantitative reverse transcription PCR.

RESULTS

A single transcription start site was identified for FAT4 in gastric epithelial cells, and a CpG island was located in the FAT4 promoter region. FAT4 was highly methylated in two of 13 GC cell lines and was not expressed in them. Removal of FAT4 methylation by a DNA demethylating agent (5-aza-2'-deoxycytidine) restored its expression in the two cell lines. In primary GC samples, FAT4 was methylated in 12 of 82 GCs (14.6 %). FAT4 methylation was associated with the presence of the CpG island methylator phenotype but not with prognosis, tumor invasion, lymph node metastasis, or histological types. In noncancerous gastric mucosae, high FAT4 methylation levels were associated with the presence of GC and Helicobacter pylori infection.

CONCLUSIONS

FAT4 was methylation-silenced in GCs. Its methylation in gastric mucosae was associated with H. pylori infection and likely contributed to epigenetic field cancerization.

History and progression of Fat cadherins in health and disease

Intercellular adhesions are vital hubs for signaling pathways during multicellular development and animal morphogenesis. In eukaryotes, under aberrant intracellular conditions, cadherins are abnormally regulated, which can result in cellular pathologies such as carcinoma, kidney disease, and autoimmune diseases. As a member of the Ca²⁺-dependent adhesion super-family, Fat proteins were first described in the 1920s as an inheritable lethal mutant phenotype in Drosophila, consisting of four member proteins, FAT1, FAT2, FAT3, and FAT4, all of which are highly conserved in structure. Functionally, FAT1 was found to regulate cell migration and growth control through specific protein–protein interactions of its cytoplasmic tail. FAT2 and FAT3 are relatively less studied and are thought to participate in the development of human cancer through a pathway similar to that of the Ena/VASP proteins. In contrast, FAT4 has been widely studied in the context of biological functions and tumor mechanisms and has been shown to regulate the planar cell polarity pathway, the Hippo signaling pathway, the canonical Wnt signaling cascade, and the expression of YAP1. Overall, Fat cadherins may be useful as emerging disease biomarkers and as novel therapeutic targets.

Inhibition of green tea polyphenol EGCG((-)-epigallocatechin-3-gallate) on the proliferation of gastric cancer cells by suppressing canonical wnt/β-catenin signalling pathway

(-)-Epigallocatechin-3-gallate (EGCG), the major polyphenol in green tea, could affect carcinogenesis and development of many cancers. However, the effects and underlying mechanisms of EGCG on gastric cancer remain unclear. We found that EGCG significantly inhibited proliferation and increased apoptosis of SGC-7901 cells in vitro. The decreased expressions of p-β-catenin(Ser552), p-GSK3β(S9) and β-catenin target genes were detected in SGC-7901 cells after treated by EGCG. XAV939 and β-catenin plasmid were further used to demonstrate the inhibition of EGCG on canonical Wnt/β-catenin signalling. Moreover, EGCG significantly inhibited gastric tumour growth in vivo by inhibiting Wnt/β-catenin signalling. Taken together, our findings establish that EGCG suppressed gastric cancer cell proliferation and demonstrate that this inhibitory effect is related to canonical Wnt/β-catenin signalling. This study raises a new insight into gastric cancer prevention and therapy, and provides evidence that green tea could be used as a nutraceutical beverage.

Interaction between Wnt/β-catenin pathway and microRNAs regulates epithelial-mesenchymal transition in gastric cancer (Review)

Gastric cancer (GC) is the third primary cause of cancer-related mortality and one of the most common type of malignant diseases worldwide. Despite remarkable progress in multimodality therapy, advanced GC with high aggressiveness always ends in treatment failure. Epithelial-mesenchymal transition (EMT) has been widely recognized to be a key process associating with GC evolution, during which cancer cells go through phenotypic variations and acquire the capability of migration and invasion. Wnt/β-catenin pathway has established itself as an EMT regulative signaling due to its maintenance of epithelial integrity as well as tight adherens junctions while mutations of its components will lead to GC initiation and diffusion. The E-cadherin/β-catenin complex plays an important role in stabilizing β-catenin at cell membrane while disruption of this compound gives rise to nuclear translocation of β-catenin, which accounts for upregulation of EMT biomarkers and unfavorable prognosis. Additionally, several microRNAs positively or negatively modify EMT by reciprocally acting with certain target genes of Wnt/β-catenin pathway in GC. Thus, this review centers on the strong associations between Wnt/β-catenin pathway and microRNAs during alteration of EMT in GC, which may induce advantageous therapeutic strategies for human gastric cancer.

Aquaporin-1 retards renal cyst development in polycystic kidney disease by inhibition of Wnt signaling

Water channel aquaporin-1 (AQP1) is expressed at epithelial cell plasma membranes in renal proximal tubules and thin descending limb of Henle. Recently, AQP1 was reported to interact with β-catenin. Here we investigated the relationship between AQP1 and Wnt signaling in in vitro and in vivo models of autosomal dominant polycystic kidney disease (PKD). AQP1 overexpression decreased β-catenin and cyclinD1 expression, suggesting down-regulation of Wnt signaling, and coimmunoprecipitation showed AQP1 interaction with β-catenin, glycogen synthase kinase 3β, LRP6, and Axin1. AQP1 inhibited cyst development and promoted branching in matrix-grown MDCK cells. In embryonic kidney cultures, AQP1 deletion increased cyst development by up to ∼ 40%. Kidney size and cyst number were significantly greater in AQP1-null PKD mice than in AQP1-expressing PKD mice, with the difference mainly attributed to a greater number of proximal tubule cysts. Biochemical analysis revealed decreased β-catenin phosphorylation and increased β-catenin expression in AQP1-null PKD mice, suggesting enhanced Wnt signaling. These results implicate AQP1 as a novel determinant in renal cyst development that may involve inhibition of Wnt signaling by an AQP1-macromolecular signaling complex.

Abnormal β-catenin immunohistochemical expression as a prognostic factor in gastric cancer: A meta-analysis

AIM: To evaluate the effect of β-catenin immunohistochemical expression on the prognosis of gastric cancer (GC).

METHODS: We searched Pubmed and Embase to identify eligible studies. The search ended on November 10, 2013, with no lower date limit. The citation lists associated with the studies were used to identify additional eligible studies. We included studies reporting sufficient information to estimate the HR and 95%CI, and information to estimate the OR in the analysis of clinicopathological features. The qualities of these studies were assessed using the Newcastle-Ottawa Quality Assessment Scale. HRs and ORs and their variance were calculated and pooled using Review Manager Version 5.2.

RESULTS: A total of 24 studies were identified and comprised 3404 cases. β-catenin expression was significantly correlated with poor overall survival (OS) in GC patients (HR = 1.85, 95%CI: 1.39-2.46), but showed a significant degree of heterogeneity (I² = 71%, P < 0.0001). Subgroup analysis indicated that an abnormal pattern of β-catenin expression had an unfavorable effect on OS (HR = 1.79, 95%CI: 1.39-2.32). However, accumulation in the nucleus or loss of membrane did not influence the survival of GC patients independently. Moreover, the combined OR of β-catenin indicated that β-catenin expression was associated with Lauren classification (OR = 1.98, 95%CI: 1.19-3.29), lymph node metastasis (OR = 2.00, 95%CI: 1.44-2.77), distant metastasis (OR = 2.69, 95%CI: 1.35-5.38) and grade of differentiation (OR = 2.68, 95%CI: 1.66-4.34). β-catenin expression did not correlate with TNM stage (OR = 1.34 95%CI: 0.96-1.86), the depth of invasion (OR = 1.48, 95%CI: 0.94-2.33) or vascular invasion (OR = 1.11, 95%CI: 0.70-1.76).

CONCLUSION: Abnormal β-catenin immunohistochemical expression may be associated with tumor progression and could be a predictive factor of poor prognosis in patients with GC.

β-Catenin serves as a clutch between low and high intercellular E-cadherin bond strengths

A wide range of invasive pathological outcomes originate from the loss of epithelial phenotype and involve either loss of function or downregulation of transmembrane adhesive receptor complexes, including Ecadherin (Ecad) and binding partners β-catenin and α-catenin at adherens junctions. Cellular pathways regulating wild-type β-catenin level, or direct mutations in β-catenin that affect the turnover of the protein have been shown to contribute to cancer development, through induction of uncontrolled proliferation of transformed tumor cells, particularly in colon cancer. Using single-molecule force spectroscopy, we show that depletion of β-catenin or the prominent cancer-related S45 deletion mutation in β-catenin present in human colon cancers both weaken tumor intercellular Ecad/Ecad bond strength and diminishes the capacity of specific extracellular matrix proteins-including collagen I, collagen IV, and laminin V-to modulate intercellular Ecad/Ecad bond strength through α-catenin and the kinase activity of glycogen synthase kinase 3 (GSK-3β). Thus, in addition to regulating tumor cell proliferation, cancer-related mutations in β-catenin can influence tumor progression by weakening the adhesion of tumor cells to one another through reduced individual Ecad/Ecad bond strength and cellular adhesion to specific components of the extracellular matrix and the basement membrane.

Carbonic anhydrase IX: regulation and role in cancer

Tumor microenvironment substantially influences the process of tumorigenesis. In many solid tumors, imbalance between the demand of rapidly proliferating cancer cells and the capabilities of the vascular system generates areas with insufficient oxygen supply. In response to tumor hypoxia, cancer cells modulate their gene expression pattern to match the requirements of the altered microenvironment. One of the most significant adaptations to this milieu is the shift towards anaerobic glycolysis to keep up the energy demands. This oncogenic metabolism is often maintained also in aerobic cells. Lactic acid, its metabolic end-product, accumulates hand-in-hand with carbon dioxide, leading to acidification of the extracellular environment. Carbonic anhydrase IX (CA IX) is the most widely expressed gene in response to hypoxia. Its crucial role in intracellular pH maintenance represents the means by which cancer cells adapt to the toxic conditions of the extracellular milieu. Furthermore, the activity of CA IX stimulates the migratory pathways of cancer cells and is connected with the increase of the aggressive/invasive phenotype of tumors. CA IX expression in many types of tumors indicates its relevance as a general marker of tumor hypoxia. Moreover, its expression is closely related to prognosis of the clinical outcome in several tumor types. All above mentioned facts support the strong position of CA IX as a potential drug therapy target. Here, we summarize the state-of-the-art knowledge on its regulation and role in cancer development.

SIRT1 Expression Is Associated with Good Prognosis in Colorectal Cancer

Background

Silent mating type information regulation 2 homolog 1 (SIRT1), an NAD+-dependent deacetylase, might act as a tumor promoter by inhibiting p53, but may also as a tumor suppressor by inhibiting several oncogenes such as β-catenin and survivin. Deleted in breast cancer 1 (DBC1) is known as a negative regulator of SIRT1.

Methods

Immunohistochemical expressions of SIRT1, DBC1, β-catenin, surviving, and p53 were evaluated using 2 mm tumor cores from 349 colorectal cancer patients for tissue microarray.

Results

Overexpression of SIRT1, DBC1, survivin, and p53 was seen in 235 (67%), 183 (52%), 193 (55%), and 190 (54%) patients, respectively. Altered expression of β-catenin was identified in 246 (70%) patients. On univariate analysis, overexpression of SIRT1 (p=0.029) and altered expression of β-catenin (p=0.008) were significantly associated with longer overall survival. Expression of SIRT1 was significantly related to DBC1 (p=0.001), β-catenin (p=0.001), and survivin (p=0.002), but not with p53. On multivariate analysis, age, tumor stage, differentiation, and expression of SIRT1 were independent prognostic factors significantly associated with overall survival.

Conclusions

SIRT1 overexpression is a good prognostic factor for colorectal cancer, and SIRT1 may interact with β-catenin and survivin rather than p53.

Tumor suppressor function of ezrin-radixin-moesin-binding phosphoprotein-50 through β-catenin/E-cadherin pathway in human hepatocellular cancer

AIM: To determine the effect and molecular mechanism of ezrin-radixin-moesin-binding phosphoprotein-50 (EBP50) in hepatocellular carcinoma (HCC).

METHODS: Three human HCC cell lines, i.e., SM-MC7721, HepG2 and Hep3B, were used. We transfected the Pbk-CMV-HA-EBP50 plasmid into SMMC7721 cells with Lipofectamine 2000 to overexpress EBP50. Western blotting were performed to determine the effects of the plasmid on EBP50 expression and to detect the expression of β-catenin and E-cadherin before and after the transfection of the plasmid into SMMC7721 cells. In vitro cell proliferation was assessed with a Cell Counting Kit-8 (CCK-8) assay. Cell cycle distribution was assessed with flow cytometry. Invasion and migration ability of before and after the transfection were determined with a transwell assay. Cell apoptosis was demonstrated with Annexin V-FITC. The effect of EBP50 overexpressing on tumor growth in vivo was performed with a xenograft tumor model in nude mice.

RESULTS: The transfection efficiency was confirmed with Western blotting (1.36 ± 0.07 vs 0.81 ± 0.09, P < 0.01). The CCK8 assay demonstrated that the growth of cells overexpressing EBP50 was significantly lower than control cells (P < 0.01). Cell cycle distribution showed there was a G0/G1 cell cycle arrest in cells overexpressing EBP50 (61.3% ± 3.1% vs 54.0% ± 2.4%, P < 0.05). The transwell assay showed that cell invasion and migration were significantly inhibited in cells overexpressing EBP50 compared with control cells (5.8 ± 0.8 vs 21.6 ± 1.3, P < 0.01). Annexin V-FITC revealed that apoptosis was significantly increased in cells overexpressing EBP50 compared with control cells (14.8% ± 2.7% vs 3.4% ± 1.3%, P < 0.05). The expression of β-catenin was downregulated and E-cadherin was upregulated in cells overexpressing EBP50 compared with control cells (0.28 ± 0.07 vs 0.56 ± 0.12, P < 0.05; 0.55 ± 0.08 vs 0.39 ± 0.07, P < 0.05). In vivo tumor growth assay confirmed that up-regulation of EBP50 could obviously slow the growth of HCC derived from SMMC7721 cells (28.9 ± 7.2 vs 70.1 ± 7.2, P < 0.01).

CONCLUSION: The overexpression of EBP50 could inhibit the growth of SMMC7721 cells and promote apoptosis by modulating β-catenin, E-cadherin. EBP50 may serve asa potential therapeutic target in HCC.

Up-regulation of thy-1 promotes invasion and metastasis of hepatocarcinomas

Increasing evidence has revealed that thy-1 was a potential stem cell marker of liver cancer, but no data have been shown on how thy-1 regulates the pathophysiology of liver cancer, such as proliferation, apoptosis, invasion and migration. We previously demonstrated that thy-1 was expressed in about 1% of hepg2 cells, thy-1+ hepg2 cells, but not thy-1-, demonstrating high tumorigenesis on inoculation 0.5x10⁵ cells per BACA/LA mouse after 2 months. In the present study, our results showed that higher expression of thy-1 occurs in 72% (36/50 cases) of neoplastic hepatic tissues as compared to 40% (20/50 cases) of control tissues, and the expression of thy-1 is higher in poorly differentiated liver tumors than in the well-differentiated ones. In addition, thy-1 expression was detected in 85% of blood samples from liver cancer patients, but none in normal subjects or patients with cirrhosis or hepatitis. There was a significant negative correlation between thy-1 expression and E-cadherin expression (a marker of invasion and migraton), but not between thy-1 expression and AFP expression in all the liver cancer and blood samples. We further investigated the relationship between thy-1 and E- cadherin in liver cancer hepg2 cell line which was transfected with pReceiver-M29/thy-1 eukaryotic expression vector followed by aspirin treatment. Lower expression of E- cadherin but higher expressions of thy-1 were detected in hepg2 cells transfected with pReceiver-M29/thy-1. Taken together, our study suggested that thy-1 probably regulates liver cancer invasion and migration.

Expression of SIRT1 and DBC1 in Gastric Adenocarcinoma

BACKGROUND

Sirtuin 1 (SIRT1) and deleted in breast cancer 1 (DBC1) are known as tumor suppressor or promoter genes. This may be due to their diverse functions and interaction with other proteins. Gastric adenocarcinoma is one of the most common malignancies, but little is known about its carcinogenesis. Therefore, we investigated the association of immunohistochemical expression of SIRT1, DBC1, p53, and β-catenin and their variable clinicopathological characteristics.

METHODS

We obtained samples from 452 patients who underwent gastrectomy. Tissue microarray blocks were constructed and immonohistochemical staining was performed.

RESULTS

Expression of DBC1 and SIRT1 was associated with lower histologic grade, intestinal type of Lauren classification, and lower pT (p<0.001) and pN stage (DBC1, p=0.002; SIRT1, p<0.001). Association between absence of lymphatic invasion, and SIRT1 (p=0.001) and DBC1 (p=0.004) was observed. Cytoplasmic β-catenin expression was associated with lower histologic grade, pT, pN, tumor-node-metastasis (TNM) stage, DBC1 (p<0.001), and SIRT1 (p=0.001). Expression of SIRT1 and DBC1 was not associated with p53 (p=0.063 and p=0.060). DBC1 was an independent good prognostic factor in multivariate analysis (p=0.012).

CONCLUSIONS

SIRC1 and DBC1 can be considered to be good prognostic factors in gastric adenocarcinoma.

Impact of 4HPR on the expression of E-Cad in human bladder transitional epithelial cancer cells T24

Previous researches showed that the expression level of E-Cad in most infiltrating cancer cells was reduced or negative. This study explored whether 4HPR restrained the infiltration of bladder cancer cells through regulating the expression of E-Cad. The infiltrating bladder cancer cells T24 were cultured, and then treated by a proper dosage of drug. Their viability was a determined by MTT method. Western blotting and RT-PCR were adopted to detect the changes of E-Cad gene expression at both protein and mRNA levels. Moreover, immunofluorescent staining and confocal fluorescence microscopy were employed for the observation of the expression of E-Cad. The result showed that, at both mRNA and protein levels, the expression level of E-Cad in T24 cells treated by 4HPR was significantly higher than that of control group, while the β-Cat expression was also relocated from the cell nucleus to cytoplasm. Our findings suggested that the regulatory function of 4HPR on infiltration of bladder cancer cells T24 is at least partly achieved by regulating the expression of E-Cad.

CDH1 methylation in preoperative peritoneal washes is an independent prognostic factor for gastric cancer

Background and Objectives

To investigate the clinical value of CDH1 methylation in preoperative peritoneal washes (PPW) from gastric cancer patients.

Methods

CDH1 methylation was detected by real-time methylation specific-PCR in tumor tissues and corresponding PPW from 92 gastric cancer patients, gastric mucosa from 40 chronic gastritis patients and 48 normal persons.

Results

CDH1 methylation was found in 75 of 92 (81.5%) gastric cancer tissues, which significantly correlated with size, growth pattern, differentiation, lymphatic invasion, venous invasion, invasion depth, lymph node metastasis, distant metastasis, and TNM stage of tumor (all P < 0.05), but its relationship to age, gender, tumor site, and H. pylori infection was not found (all P > 0.05). The percentage of CDH1 methylation in PPW was 48.9%, of which the Aζ value of ROC curve was 0.8 compared to that in gastric cancer tissues. Kaplan–Meier analysis showed that there was a significant difference in disease-free survival (DFS) between the patients with or without methylated CDH1 in their PPW (χ² = 109.64, P < 0.000). Cox regression analysis revealed CDH1 methylation in PPW was an independent risk factor for gastric cancer patients, with a remarkable decrease in DFS after postoperative 30 months.

Conclusions

Methylated CDH1 in PPW predicts poor prognosis for gastric cancer patients. J. Surg. Oncol. 2012; 106:765–771. © 2012 Wiley Periodicals, Inc.

DLC1 interaction with α-catenin stabilizes adherens junctions and enhances DLC1 antioncogenic activity

The DLC1 (for deleted in liver cancer 1) tumor suppressor gene encodes a RhoGAP protein that inactivates Rho GTPases, which are implicated in regulation of the cytoskeleton and adherens junctions (AJs), a cell-cell adhesion protein complex associated with the actin cytoskeleton. Malignant transformation and tumor progression to metastasis are often associated with changes in cytoskeletal organization and cell-cell adhesion. Here we have established in human cells that the AJ-associated protein α-catenin is a new binding partner of DLC1. Their binding was mediated by the N-terminal amino acids 340 to 435 of DLC1 and the N-terminal amino acids 117 to 161 of α-catenin. These proteins colocalized in the cytosol and in the plasma membrane, where together they associated with E-cadherin and β-catenin, constitutive AJ proteins. Binding of DLC1 to α-catenin led to their accumulation at the plasma membrane and required DLC1 GAP activity. Knocking down α-catenin in DLC1-positive cells diminished DLC1 localization at the membrane. The DLC1-α-catenin complex reduced the Rho GTP level at the plasma membrane, increased E-cadherin's mobility, affected actin organization, and stabilized AJs. This process eventually contributed to a robust oncosuppressive effect of DLC1 in metastatic prostate carcinoma cells. Together, these results unravel a new mechanism through which DLC1 exerts its strong oncosuppressive function by positively influencing AJ stability.

Polycomb genes and cancer: time for clinical application?

Polycomb group genes (PcGs) are epigenetic effectors, essential for stem cell self-renewal and pluripotency. Two main Polycomb repressive complexes (PRC1, PRC2) mediate gene silencing through histone post-translational modifications. PcGs have been the focus of investigation in cancer research. Many cancer types show an over-expression of PcGs, predicting poor prognosis, metastasis and chemoresistance. Genetic polymorphisms of EZH2 (a PRC2 component) are significantly associated to lung cancer risk. Recently, 3-Deazaneplanocin A (DZNeP) was identified as an efficient inhibitor of PRC2 activity. DZNeP impairs cancer stem cell self-renewal and tumorigenicity. Despite the well-established role of PcGs in cancer stem cell biology, few studies dissected the clinical significance of these genes. In this paper, we explore PcGs as predictive and prognostic factors in oncology, with particular emphasis on what they can add to current biomarkers. We also propose a model for the rational development of DZNeP-based anticancer regimens and suggest the therapeutic applications of this drug.

Pathology, genetics and cytogenetics of Wilms' tumour

Wilms' tumour (WT) is an embryonal cancer of childhood and is thought to be derived from embryonic kidney precursor cells. The Knudson two hit model was initially thought to occur in WT, but findings emerging from genetic and cytogenetic studies in the past two decades have implicated several genetic events. Recent techniques in genetic analysis have improved our ability to characterise changes in genes involved in WT which include WT1, CTNNB1, IGF2 and WTX. These genetic events have not only provided insight into the pathobiology of this malignancy, but the recognition of these candidate genes may offer potential targets for novel therapies. In this review, we will provide an overview of the pathological, genetic and cytogenetic characteristics of WT.

Clinical significance of serum levels of soluble E-cadherin in patients with gastric carcinoma

AIM: To measure serum levels of soluble E-cadherin (sE-cadherin) in patients with gastric cancer and to evaluate the relationship of serum levels of sE-cadherin with tumor clinicopathological features and patient survival.

METHODS: Peripheral blood samples were collected from 127 gastric cancer patients and 31 healthy controls from March 2003 to September 2004. Serum levels of sE-cadherin were measured using double-antibody sandwich enzyme-linked immunosorbent assay. The clinical pathological data and survive data for all patients were recorded.

RESULTS: Serum levels of sE-cadherin were significantly higher in patients with gastric cancer than in healthy controls (43.83 μg/L ± 15.77 μg/L vs 17.17 μg/L ± 5.38 μg/L, P = 0.000, t = 8.34). Serum levels of sE-cadherin were closely associated with tumor differentiation, depth of invasion and lymph node metastasis (all P < 0.05). Patients with lower levels of serum sE-cadherin had significant survival advantage over those with higher levels of serum sE-cadherin (P < 0.001), and such survival advantage was independent of depth of invasion, lymph node metastasis and tumor differentiation.

CONCLUSION: sE-cadherin may serve as a potential biological marker for the diagnosis and prognosis of gastric cancer.