Disturbed expression of E-cadherin, beta-catenin and tight junction proteins in colon carcinoma is unrelated to growth pattern and genetic polymorphisms

Reduced occludin expression is related to unfavorable tumor phenotype and poor prognosis in many different tumor types: A tissue microarray study on 16,870 tumors

Occludin is a key component of tight junctions. Reduced occludin expression has been linked to cancer progression in individual tumor types, but a comprehensive and standardized analysis across human tumor types is lacking. To study the prevalence and clinical relevance of occludin expression in cancer, a tissue microarray containing 16,870 samples from 148 different tumor types and 608 samples of 76 different normal tissue types was analyzed by immunohistochemistry. Occludin immunostaining was observed in 10,746 (76.6%) of 14,017 analyzable tumors, including 18.9% with weak, 16.2% with moderate, and 41.6% with strong staining intensity. Occludin positivity was found in 134 of 148 tumor categories and was most frequent in adenocarcinomas (37.5-100%) and neuroendocrine neoplasms (67.9-100%), less common in squamous cell carcinomas (23.8-93%) and in malignant mesotheliomas (up to 48.1%), and rare in Non-Hodgkin's lymphomas (1-2%) and most mesenchymal tumors. Reduced occludin staining was linked to adverse tumor features in several tumor types, including colorectal adenocarcinoma (advanced pT stage, p < 0.0001; L1 status, p = 0.0384; absence of microsatellite instability, p < 0.0001), pancreatic adenocarcinoma (advanced pT stage, p = 0.005), clear cell renal cell carcinoma (high ISUP grade, p < 0.0001; advanced pT stage, p < 0.0001; high UICC stage, p < 0.0001; distant metastasis, p = 0.0422; shortened overall or recurrence-free survival, p ≤ 0.0116), papillary renal cell carcinoma (high pT stage, p < 0.0001; high UICC stage, p = 0.0228; distant metastasis, p = 0.0338; shortened recurrence-free survival, p = 0.006), and serous high-grade ovarian cancer (advanced pT stage, p = 0.0133). Occludin staining was unrelated to parameters of tumor aggressiveness in breast, gastric, endometrial, and thyroidal cancer. Our data demonstrate significant levels of occludin expression in many different tumor entities and identify reduced occludin expression as a potentially useful prognostic feature in several tumor entities.

Fractal nature of human gastrointestinal system: Exploring a new era

The morphological complexity of cells and tissues, whether normal or pathological, is characterized by two primary attributes: Irregularity and self-similarity across different scales. When an object exhibits self-similarity, its shape remains unchanged as the scales of measurement vary because any part of it resembles the whole. On the other hand, the size and geometric characteristics of an irregular object vary as the resolution increases, revealing more intricate details. Despite numerous attempts, a reliable and accurate method for quantifying the morphological features of gastrointestinal organs, tissues, cells, their dynamic changes, and pathological disorders has not yet been established. However, fractal geometry, which studies shapes and patterns that exhibit self-similarity, holds promise in providing a quantitative measure of the irregularly shaped morphologies and their underlying self-similar temporal behaviors. In this context, we explore the fractal nature of the gastrointestinal system and the potential of fractal geometry as a robust descriptor of its complex forms and functions. Additionally, we examine the practical applications of fractal geometry in clinical gastroenterology and hepatology practice.

Colorectal adenocarcinoma with mucinous component: relation of MMP-13, EGFR, and E-cadherin expressions to clinicopathological features and prognosis

The aim of this study was to compare colorectal adenocarcinoma with mucinous component, ordinary adenocarcinoma (OA) and mucinous adenocarcinoma (MA) regarding clinicopathological parameters, survival, EGFR, MMP-13, and E-cadherin. We studied tumor tissue specimens from 28 patients with adenocarcinoma with mucinous component, 47 with OA, and 56 with MA, who underwent radical surgery from January 2007 to January 2012 at the Gastroenterology Centre, Mansoura University, Egypt. High density manual tissue microarrays were constructed and immunohistochemistry for EGFR, MMP-13, and E-cadherin was done. Colorectal adenocarcinoma with mucinous component (AWMC) was significantly associated with more perineural invasion, lower EGFR, and MMP-13 expressions than OA, with no difference in E-cadherin expression. Conversely, only microscopic abscess formation was significantly more with colorectal AWMC than MC with no difference in EGFR, MMP-13 and E-cadherin expression between both groups. Colorectal AWMC showed a better survival than MA with no difference with OA. In a univariate analysis, EGFR, MMP-13, and E-cadherin expressions did not show a significant impact on disease-free or overall survival in patients with colorectal AWMC. Colorectal AWMC remains a vague entity that resembles OA in some clinicopathological and molecular respects as well as MA.

Relation of glypican-3 and E-cadherin expressions to clinicopathological features and prognosis of mucinous and non-mucinous colorectal adenocarcinoma

Glypican-3 (GPC3) is a member of the membrane-bound heparin sulfate proteoglycans. E-cadherin is an adhesive receptor that is believed to act as a tumor suppressor gene. Many studies had investigated E-cadherin expressions in colorectal carcinoma (CRC) while only one study had investigated GPC3 expression in CRC. This study aims to investigate expression of GCP3 and E-cadherin in colorectal mucinous carcinoma (MA) and non-mucinous adenocarcinoma (NMA) using manual tissue microarray technique. Tumor tissue specimens are collected from 75 cases of MC and 75 cases of NMA who underwent radical surgery from Jan 2007 to Jan 2012 at the Gastroenterology Centre, Mansoura University, Egypt. Their clinicopathological parameters and survival data were revised and analyzed using established statistical methodologies. High-density manual tissue microarrays were constructed using modified mechanical pencil tip technique and immunohistochemistry for GPC3 and E-cadherin was done. NMA showed higher expression of GPC3 than MA with no statistically significant relation. NMA showed a significantly higher E-cadherin expression than MA. GPC3 and E-cadherin positivity rates were significantly interrelated in NMA, but not in MA, group. In NMA group, there was no significant relation between either GPC3 or E-cadherin expression and the clinicopathological features. In a univariate analysis, neither GPC3 nor E-cadherin expression showed a significant impact on disease-free survival (DFS) or overall survival (OS). GPC3 and E-cadherin expressions are not independent prognostic factors in CRC. However, expressions of both are significantly interrelated in NMA patients, suggesting an excellent interplay between both, in contrast to MA. Further molecular studies are needed to further explore the relationship between GCP3 and E-cadherin in colorectal carcinogenesis.

Investigating the association between polymorphisms in connective tissue growth factor and susceptibility to colon carcinoma

There have been numerous studies on the gene expression of connective tissue growth factor (CTGF) in colorectal cancer, however very few have investigated polymorphisms in this gene. The present study aimed to determine whether single nucleotide polymorphisms (SNPs) in the CTGF gene are associated with a higher susceptibility to colon cancer and/or an invasive tumor growth pattern. The CTGF gene was genotyped for seven SNPs (rs6918698, rs1931002, rs9493150, rs12526196, rs12527705, rs9399005 and rs12527379) by pyrosequencing. Formalin-fixed paraffin-embedded tissue samples (n=112) from patients diagnosed with colon carcinoma, and an equal number of blood samples from healthy controls, were selected for genomic DNA extraction. The complexity index was measured using images of tumor samples (n=64) stained for cytokeratin-8. The images were analyzed and correlated with the identified CTGF SNPs and clinicopathological parameters of the patients, including age, gender, tumor penetration, lymph node metastasis, systemic metastasis, differentiation and localization of tumor. It was demonstrated that the frequency of the SNP rs6918698 GG genotype was significantly associated (P=0.05) with an increased risk of colon cancer, as compared with the GC and CC genotypes. The other six SNPs (rs1931002, rs9493150, rs12526196, rs12527705, rs9399005 and rs12527379) exhibited no significant difference in the genotype and allele frequencies between patients diagnosed with colon carcinoma and the normal healthy population. A trend was observed between genotype variation at rs6918698 and the complexity index (P=0.052). The complexity index and genotypes for any of the studied SNPs were not significantly correlated with clinical or pathological parameters of the patients. These results indicate that the rs6918698 GG genotype is associated with an increased risk of developing colon carcinoma, and genetic variations at the rs6918698 are associated with the growth pattern of the tumor. The present results may facilitate the identification of potential biomarkers of the disease in addition to drug targets.

Fascin promotes the motility and invasiveness of pancreatic cancer cells

AIM: To explore the role of actin-bundling protein, fascin during the progression of pancreatic cancer.

METHODS: The plasmid expressing human fascin-1 was stably transfected into the pancreatic cancer cell line MIA PaCa-2. The proliferation, cell cycle, motility, scattering, invasiveness and organization of the actin filament system in fascin-transfected MIA PaCa-2 cells and control non-transfected cells were determined.

RESULTS: Heterogeneous overexpression of fascin markedly enhanced the motility, scattering, and invasiveness of MIA PaCa-2 cells. However, overexpression of fascin had minimal effect on MIA PaCa-2 cell proliferation and cell cycle. In addition, cell morphology and organization of the actin filament system were distinctly altered in fascin overexpressed cells. When transplanted into BALB/c-nu mice, fascin-transfected pancreatic cancer cells developed solid tumors at a slightly slower rate, but these tumors displayed more aggressive behavior in comparison with control tumors.

CONCLUSION: Fascin promotes pancreatic cancer cell migration, invasion and scattering, thus contributes to the aggressive behavior of pancreatic cancer cells.

Prognostic significance of Wnt-1, β-catenin and E-cadherin expression in advanced colorectal carcinoma

Wnt/β-catenin pathway plays an important role in initiation and progression of colorectal oncogenesis. The aim of this study was to determine expression and localization of E-cadherin, β-catenin and Wnt-1 proteins in colorectal tumors. Expression of β-catenin, E-cadherin and Wnt-1 was determined by immunohistochemistry on advanced colorectal cancers. Abnormal expression of E-cadherin, β-catenin, Wnt-1 was observed. Additionally, we revealed correlations between levels of studied proteins and histoclinical data. In multivariate analysis nuclear β-catenin, higher carcinoembryonic antigen serum level before treatment, female sex and tumor localized in colon or rectum were independent unfavorable prognostic factors. These findings support the hypothesis that Wnt/β-catenin pathway plays an important role in advanced colorectal carcinoma.

The role of CDX2 in intestinal homeostasis and inflammation

Many transcription factors are known to control transcription at several promoters, while others are only active at a few places. However, due to their importance in controlling cellular functions, aberrant transcription factor function and inappropriate gene regulation have been shown to play a causal role in a large number of diseases and developmental disorders. Inflammatory bowel disease (IBD) is characterized by a chronically inflamed mucosa caused by dysregulation of the intestinal immune homeostasis. The aetiology of IBD is thought to be a combination of genetic and environmental factors, including luminal bacteria. The Caudal-related homeobox transcription factor 2 (CDX2) is critical in early intestinal differentiation and has been implicated as a master regulator of the intestinal homeostasis and permeability in adults. When expressed, CDX2 modulates a diverse set of processes including cell proliferation, differentiation, cell adhesion, migration, and tumorigenesis. In addition to these critical cellular processes, there is increasing evidence for linking CDX2 to intestinal inflammation. The aim of the present paper was to review the current knowledge of CDX2 in regulation of the intestinal homeostasis and further to reveal its potential role in inflammation.

Downregulation of Rap1GAP in human tumor cells alters cell/matrix and cell/cell adhesion

Rap1GAP expression is decreased in human tumors. The significance of its downregulation is unknown. We show that Rap1GAP expression is decreased in primary colorectal carcinomas. To elucidate the advantages conferred on tumor cells by loss of Rap1GAP, Rap1GAP expression was silenced in human colon carcinoma cells. Suppressing Rap1GAP induced profound alterations in cell adhesion. Rap1GAP-depleted cells exhibited defects in cell/cell adhesion that included an aberrant distribution of adherens junction proteins. Depletion of Rap1GAP enhanced adhesion and spreading on collagen. Silencing of Rap expression normalized spreading and restored E-cadherin, beta-catenin, and p120-catenin to cell/cell contacts, indicating that unrestrained Rap activity underlies the alterations in cell adhesion. The defects in adherens junction protein distribution required integrin signaling as E-cadherin and p120-catenin were restored at cell/cell contacts when cells were plated on poly-l-lysine. Unexpectedly, Src activity was increased in Rap1GAP-depleted cells. Inhibition of Src impaired spreading and restored E-cadherin at cell/cell contacts. These findings provide the first evidence that Rap1GAP contributes to cell/cell adhesion and highlight a role for Rap1GAP in regulating cell/matrix and cell/cell adhesion. The frequent downregulation of Rap1GAP in epithelial tumors where alterations in cell/cell and cell/matrix adhesion are early steps in tumor dissemination supports a role for Rap1GAP depletion in tumor progression.

Expression of tight and adherens junction proteins in ulcerative colitis associated colorectal carcinoma: upregulation of claudin-1, claudin-3, claudin-4, and beta-catenin

BACKGROUND

Tight junction (TJ) proteins play a critical role in cellular adhesion, glandular differentiation, and cellular proliferation. The function of these proteins is compromised in a number of intestinal diseases, including ulcerative colitis that has an increased incidence for colorectal carcinoma (CAC). The aim of this study was to determine the expression of TJ proteins, claudin-1-4, occludin, ZO-1, and the adherens junction (AJ) protein beta-catenin in CAC.

METHODS

Sixteen colectomy specimens with CAC, adjoining intraepithelial neoplasia, and normal mucosa were studied by immunofluorescence. A semiquantitative evaluation of all investigated proteins was performed by scoring the staining intensity, and the TJ and AJ protein expression in neoplastic cells was compared to normal and intraepithelial neoplastic colonic mucosa.

RESULTS

Using an intensity scoring system, mucosa of crypts and surfaces of CAC exhibited significantly elevated expression levels of claudin-1, claudin-3, claudin-4, and beta-catenin compared to intraepithelial neoplasia and normal mucosa (p<0.05). These data were confirmed by a comparative score. The expression of claudin-2, occludin, and ZO-1 showed no differences between the groups.

CONCLUSION

TJ proteins claudin-1, claudin-3, claudin-4, and the AJ protein beta-catenin are overexpressed in CAC. This suggests that these proteins may become potential markers and targets in CAC.

Claudin-1 and claudin-2 expression is elevated in inflammatory bowel disease and may contribute to early neoplastic transformation

Patients with inflammatory bowel disease (IBD) are at increased risk of developing colorectal adenocarcinoma. The factors that result in IBD-associated carcinogenesis are not understood. We hypothesized that altered expression of intestinal epithelial tight junction proteins might contribute to neoplastic progression. Semiquantitative immunohistochemical staining of human biopsies was used to assess expression of the tight junction proteins claudin-1, claudin-2, claudin-4, and occludin in IBD, IBD-associated dysplasia, acute, self-limited colitis (ASLC), and sporadic adenomas. Claudin-1 and claudin-2 expression was elevated in active IBD, adenomas, and IBD-associated dysplasia, but not ASLC. In contrast, claudin-4 expression was elevated in both active IBD and ASLC. Occludin expression was similar to control in all cases. Importantly, in IBD, claudin-1 and claudin-2 expression correlated positively with inflammatory activity. To investigate mechanisms underlying altered claudin expression, beta-catenin activation was assessed as nuclear localization. Like claudin-1 and claudin-2, beta-catenin was markedly activated in IBD, sporadic dysplasia, and IBD-associated dysplasia, but was only slightly activated in ASLC. Taken together, these data suggest that beta-catenin transcriptional activity is elevated in chronic injury and that this may contribute to increased claudin-1 and claudin-2 expression. We speculate that increased claudin-1 and claudin-2 expression may be involved at early stages of transformation in IBD-associated neoplasia.