Decreased expression of CD44, alpha-catenin, and deleted colon carcinoma and altered expression of beta-catenin in ulcerative colitis-associated dysplasia and carcinoma, as compared with sporadic colon neoplasms

Identification of hub genes and pathways in colitis-associated colon cancer by integrated bioinformatic analysis

Background

Colitis-associated colon cancer (CAC) patients have a younger age of onset, more multiple lesions and invasive tumors than sporadic colon cancer patients. Early detection of CAC using endoscopy is challenging, and the incidence of septal colon cancer remains high. Therefore, identifying biomarkers that can predict the tumorigenesis of CAC is in urgent need.

Results

A total of 275 DEGs were identified in CAC. IGF1, BMP4, SPP1, APOB, CCND1, CD44, PTGS2, CFTR, BMP2, KLF4, and TLR2 were identified as hub DEGs, which were significantly enriched in the PI3K-Akt pathway, stem cell pluripotency regulation, focal adhesion, Hippo signaling, and AMPK signaling pathways. Sankey diagram showed that the genes of both the PI3K-AKT signaling and focal adhesion pathways were upregulated (e.g., SPP1, CD44, TLR2, CCND1, and IGF1), and upregulated genes were predicted to be regulated by the crucial miRNAs: hsa-mir-16-5p, hsa-mir-1-3p, et al. Hub gene-TFs network revealed FOXC1 as a core transcription factor. In ulcerative colitis (UC) patients, KLF4, CFTR, BMP2, TLR2 showed significantly lower expression in UC-associated cancer. BMP4 and IGF1 showed higher expression in UC-Ca compared to nonneoplastic mucosa. Survival analysis showed that the differential expression of SPP1, CFRT, and KLF4 were associated with poor prognosis in colon cancer.

Conclusion

Our study provides novel insights into the mechanism underlying the development of CAC. The hub genes and signaling pathways may contribute to the prevention, diagnosis and treatment of CAC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12863-022-01065-7.

Transcriptome analysis of clock disrupted cancer cells reveals differential alternative splicing of cancer hallmarks genes

Emerging evidence points towards a regulatory role of the circadian clock in alternative splicing (AS). Whether alterations in core-clock components may contribute to differential AS events is largely unknown. To address this, we carried out a computational analysis on recently generated time-series RNA-seq datasets from three core-clock knockout (KO) genes (ARNTL, NR1D1, PER2) and WT of a colorectal cancer (CRC) cell line, and time-series RNA-seq datasets for additional CRC and Hodgkin’s lymphoma (HL) cells, murine WT, Arntl KO, and Nr1d1/2 KO, and murine SCN WT tissue. The deletion of individual core-clock genes resulted in the loss of circadian expression in crucial spliceosome components such as SF3A1 (in ARNTL^KO), SNW1 (in NR1D1^KO), and HNRNPC (in PER2^KO), which led to a differential pattern of KO-specific AS events. All HCT116^KO cells showed a rhythmicity loss of a crucial spliceosome gene U2AF1, which was also not rhythmic in higher progression stage CRC and HL cancer cells. AS analysis revealed an increase in alternative first exon events specific to PER2 and NR1D1 KO in HCT116 cells, and a KO-specific change in expression and rhythmicity pattern of AS transcripts related to cancer hallmarks genes including FGFR2 in HCT116_ARNTL^KO, CD44 in HCT116_NR1D1^KO, and MET in HCT116_PER2^KO. KO-specific changes in rhythmic properties of known spliced variants of these genes (e.g. FGFR2 IIIb/FGFR2 IIIc) correlated with epithelial-mesenchymal-transition signalling. Altogether, our bioinformatic analysis highlights a role for the circadian clock in the regulation of AS, and reveals a potential impact of clock disruption in aberrant splicing in cancer hallmark genes.

The prognostic significance of immunostaining of Wnt signalling pathway molecules, E-cadherin and β-catenin in colorectal carcinomacolorectal carcinoma

BACKGROUND AND STUDY AIMS

Colorectal carcinoma (CRC) is associated with high morbidity and mortality. The E-cadherin-catenin complex is crucial in the development and progression of carcinomas. This study was conducted to evaluate the relation between E-cadherin and β-catenin immunostaining and CRC outcome.

PATIENTS AND METHODS

Tissue microarrays were constructed from CRC, nodal metastases, adenomas, and normal mucosa. E-cadherin and β-catenin immunostaining was performed, and results were analyzed.

RESULTS

For E-cadherin, the membranous fraction (MF) was higher in normal mucosa, adenoma, CRC, and nodal metastasis than the cytoplasmic fraction (CF), but no difference in nodal metastasis was observed. A low MF in CRC was associated with disease relapse. For β-catenin, high MF and CF in normal mucosa, adenoma, CRC, and nodal metastasis were observed, whereas the nuclear fraction (NF) was high only in CRC. In CRC, a high CF was associated with nodal metastasis and the incidence of relapse and predicted nodal metastasis. A high NF could predict distance metastasis. A high CF in CRC was associated with favorable disease-free survival and overall survival.

CONCLUSION

Reduced E-cadherin and β-catenin immunostaining in CRC is related to prognostic factors. The Wnt/β-catenin pathway may play a crucial role in CRC progression and help identify the high risk of adverse outcomes and indicate close follow-up.

Alternative Splicing: Expanding the Landscape of Cancer Biomarkers and Therapeutics

Alternative splicing (AS) is a critical post-transcriptional regulatory mechanism used by more than 95% of transcribed human genes and responsible for structural transcript variation and proteome diversity. In the past decade, genome-wide transcriptome sequencing has revealed that AS is tightly regulated in a tissue- and developmental stage-specific manner, and also frequently dysregulated in multiple human cancer types. It is currently recognized that splicing defects, including genetic alterations in the spliced gene, altered expression of both core components or regulators of the precursor messenger RNA (pre-mRNA) splicing machinery, or both, are major drivers of tumorigenesis. Hence, in this review we provide an overview of our current understanding of splicing alterations in cancer, and emphasize the need to further explore the cancer-specific splicing programs in order to obtain new insights in oncology. Furthermore, we also discuss the recent advances in the identification of dysregulated splicing signatures on a genome-wide scale and their potential use as biomarkers. Finally, we highlight the therapeutic opportunities arising from dysregulated splicing and summarize the current approaches to therapeutically target AS in cancer.

Positive correlation of expression of L-type amino-acid transporter 1 with colorectal tumor progression and prognosis: Higher expression in sporadic colorectal tumors compared with ulcerative colitis-associated neoplasia

The role of L-type amino-acid transporter 1 (LAT1), an oncofetal protein, in tumor progression is not well known, although it is important for the survival and proliferation of cancer cells. LAT1 expression was immunohistochemically analyzed and compared in sporadic (conventional) colorectal tumors and ulcerative colitis (UC)-associated neoplasia development and progression. LAT1 expression showed a significant stepwise increase in the order: conventional low-grade tubular adenoma, high-grade tubular adenoma, and invasive adenocarcinoma. Similarly, the same increasing trend in LAT1 expression was found in UC-associated low-grade dysplasia, high-grade dysplasia, and adenocarcinoma, whereas expression was significantly lower compared with that in an adenoma-adenocarcinoma series. LAT1 expression was predominant in the upper half of mucosal lesions in low-grade adenoma. This localized difference in LAT1 expression between the upper and lower halves of mucosal lesions disappeared in conventional high-grade adenoma and adenocarcinoma. LAT1 expression in the colorectal mucosa was significantly increased in the order: nontumor mucosa, quiescent phase of UC, and active phase of UC. Considering the histological pattern of Ki-67 labeling, LAT1 expression appeared partly related to cell proliferation, but this was not significant. In relation to the prognosis of patients with sporadic phase IV colorectal adenocarcinoma, this was significantly poorer in the group with high LAT1 expression compared with that with low LAT1 expression. This suggests LAT1 expression may be used as a companion biomarker for anti-cancer therapy targeting the LAT1 molecule in colorectal cancers.

Proposal for an Organ-Specific Chronic Inflammation–Remodeling–Carcinoma Sequence

An organ-specific chronic inflammation–remodeling–carcinoma sequence has been proposed, mainly for the alimentary tract. As representative diseases, gastroesophageal reflux disease, chronic gastritis and inflammatory bowel disease (ulcerative colitis and Crohn’s disease of the colitis type) were adopted for this discussion. Tissue remodeling is such an important part of tumorigenesis in this sequence that an organ-specific chronic inflammation–remodeling–carcinoma sequence has been proposed in detail. Chronic inflammation accelerates the cycle of tissue injury and regeneration; in other words, cell necrosis (or apoptosis) and proliferation result in tissue remodeling in long-standing cases of inflammation. Remodeling encompasses epithelial cell metaplasia and stromal fibrosis, and modifies epithelial–stromal cell interactions. Further, the accumulation of genetic, epigenetic and molecular changes—as well as morphologic disorganization—also occurs during tissue remodeling. The expression of mucosal tissue adapted to chronic inflammatory injury is thought to occur at an early stage. Subsequently, dysplasia and carcinoma develop on a background of remodeling due to continuous, active inflammation. Accordingly, organ-specific chronic inflammation should be ameliorated or well controlled with appropriate monitoring if complete healing is unachievable.

An Overview of Molecular Profiles in Ulcerative Colitis-Related Cancer

Ulcerative colitis (UC) is an independent risk factor of colorectal cancer (CRC). Both genetic and epigentic events induce a unique molecular profile during the development from UC to UC-related CRC (UCRC). These molecular changes play varied roles in DNA repair, immune response, cell metabolism, and interaction with the microbiota during the carcinogenesis process. This review will systmatically discuss the molecular characteristics of UCRC and point out the future perspectives in this research field.

EB1 protein alteration characterizes sporadic but not ulcerative colitis associated colorectal cancer

Background

While carcinogenesis in Sporadic Colorectal Cancer (SCC) has been thoroughly studied, less is known about Ulcerative Colitis associated Colorectal Cancer (UCC). This study aimed to identify and validate differentially expressed proteins between clinical samples of SCC and UCC to elucidate new insights of UCC/SCC carcinogenesis and progression.

Results

Multiplex-fluorescence two-dimensional gel electrophoresis (2-D DIGE) and mass spectrometry identified 67 proteoforms representing 43 distinct proteins. After analysis by Ingenuity Pathway Analysis^® (IPA), subsequent Western blot validation proofed the differential expression of Heat shock 27 kDA protein 1 (HSPB1) and Microtubule-associated protein R/EB family, member 1 (EB1) while the latter one showed also expression differences by immunohistochemistry.

Materials and Methods

Fresh frozen tissue of UCC (n = 10) matched with SCC (n = 10) was investigated. Proteins of cancerous intestinal mucosal cells were obtained by Laser Capture Microdissection (LCM) and compared by 2-D DIGE. Significant spots were identified by mass spectrometry. After IPA, three proteins [EB1, HSPB1, and Annexin 5 (ANXA5)] were chosen for further validation by Western blotting and tissue microarray-based immunohistochemistry.

Conclusions

This study identified significant differences in protein expression of colorectal carcinoma cells from UCC patients compared to patients with SCC. Particularly, EB1 was validated in an independent clinical cohort.

Molecular Alterations of Colorectal Cancer with Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is an important etiologic factor in the development of colorectal cancer (CRC). The risk of CRC begins to increase 8 or 10 years after the diagnosis of IBD. This type of cancer is called colitis-associated CRC (CA-CRC). The molecular pathogenesis of inflammatory epithelium might play a critical role in the development of CA-CRC. Genetic alterations detected in CA-CRC such as genetic mutations, microsatellite instability, and DNA hypermethylation are also recognized in sporadic CRC; however, there are differences in the timing and frequency of molecular events between CA-CRC and sporadic CRC. Interaction between gene-environmental factors, including inflammation, lifestyle, psychological stress, and prior appendectomy, might be associated with the etiopathology of IBD. The mucosal inflammatory mediators, such as oxidant stress, free radicals, and chemokines, may cause the genetic alterations. Understanding the molecular mechanisms of CA-CRC might be important to develop clinical efficacies for patients with IBD. This review discusses the molecular characteristics of CA-CRC, especially ulcerative colitis-associated CRC, including clinical features, signaling pathways, and interactions between genetic alterations and environment involved in inflammatory carcinogenesis.

Tissue-specific patterns of gene expression in the epithelium and stroma of normal colon in healthy individuals in an aspirin intervention trial

Background

Regular aspirin use reduces colon adenoma and carcinoma incidence. UDP-glucuronosyltransferases (UGT) are involved in aspirin metabolism and clearance, and variant alleles in UGT1A6 have been shown to alter salicylic acid metabolism and risk of colon neoplasia.

Methods

In a randomized, cross-over, placebo-controlled trial of 44 healthy men and women, homozygous for UGT1A6*1 or UGT1A6*2, we explored differences between global epithelial and stromal expression, using Affymetrix U133 + 2.0 microarrays and tested effects of 60-day aspirin supplementation (325 mg/d) on epithelial and stromal gene expression and colon prostaglandin E2 (PGE2) levels.

Results

No statistically significant differences in gene expression were observed in response to aspirin or UGT1A6 genotype, but tissue PGE2 levels were lower with aspirin compared to placebo (p <0.001). Transcripts differentially expressed between epithelium and stroma (N = 4916, P <0.01, false discovery rate <0.001), included a high proportion of genes involved in cell signaling, cellular movement, and cancer. Genes preferentially expressed in epithelium were involved in drug and xenobiotic metabolism, fatty acid and lipid metabolism, apoptosis signaling, and ion transport. Genes preferentially expressed in stroma included those involved in inflammation, cellular adhesion, and extracellular matrix production. Wnt-Tcf4 pathway genes were expressed in both epithelium and stroma but differed by subcellular location.

Conclusions

These results suggest that, in healthy individuals, subtle effects of aspirin on gene expression in normal colon tissue are likely overwhelmed by inter-individual variability in microarray analyses. Differential expression of critical genes between colonic epithelium and stroma suggest that these tissue types need to be considered separately.

Electronic supplementary material

The online version of this article (doi:10.1186/s12881-015-0161-6) contains supplementary material, which is available to authorized users.

Colocalization of β-catenin with Notch intracellular domain in colon cancer: a possible role of Notch1 signaling in activation of CyclinD1-mediated cell proliferation

The Wnt and Notch1 signaling pathways play major roles in intestinal development and tumorigenesis. Sub-cellular localization of β-catenin has been implicated in colorectal carcinogenesis. However, the β-catenin and Notch intracellular domain (NICD) interaction has to be addressed. Immunohistochemistries of β-catenin, NICD, and dual immunofluorescence of β-catenin and NICD were analyzed in colorectal tissues and HT29 cell line. Moreover, real-time PCR analysis of CyclinD1, Hes1 and MUC2 was done in HT29 cells upon N-[N-(3, 5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT) treatment. Dual staining emphasized the strong interaction of β-catenin and NICD in adenoma and adenocarcinoma than in normal tissues. Hes1 transcript levels were decreased 1.5- and 7.1-fold in 12.5 and 25 µM DAPT-treated HT29 cells. CyclinD1 transcript levels decreased 1.2- and 1.6-fold, and MUC2 transcript level increased 4.3- and 7.5-fold in 12.5 and 25 µM DAPT-treated HT29 cells. The results of this study showed that the sub-cellular localization of β-catenin converges with NICD inducing proliferation through the activation of CyclinD1 and Hes1. Moreover, the inhibition of Notch1 signaling by DAPT leads to the arrest of cell proliferation and induces apoptosis leading to the upregulation of MUC2, a secretory cell lineage marker.

Colon Macrophages Polarized by Commensal Bacteria Cause Colitis and Cancer through the Bystander Effect

Intestinal commensal bacteria have recently been shown to trigger macrophages to produce diffusible clastogens (or chromosome-breaking factors) through a bystander effect (BSE) that mediates DNA damage and induces chromosomal instability in neighboring cells. Colon macrophages appear central to colon carcinogenesis and BSE through the expression of tumor necrosis factor-α (TNF-α) and cyclooxygenase-2 (COX-2). The former induces netrin-1, a regulator of intestinal epithelial cell apoptosis, and the latter generates trans-4-hydroxy-2-nonenal (4-HNE), an endogenous mutagen. To test whether colon macrophages are key effectors for BSE, we depleted these cells in interleukin-10 knockout mice colonized with Enterococcus faecalis using encapsulated liposomal clodronate (ELC), a bisphosphonate that causes macrophage apoptosis. We observed that E. faecalis polarizes colon macrophages to an M1 phenotype. In addition, depleting these cells suppressed COX-2 and TNF-α, blocked the formation of 4-HNE protein adducts, and inhibited up-regulation of netrin-1-all markers for BSE. Finally, treatment with ELC prevented colitis, β-catenin activation, and cancer formation. These results show that selected human commensals can polarize colon macrophages to the M1 phenotype and, when activated, serve as the key effector for bacterial-induced BSE. Our findings suggest that depleting M1-polarized macro-phages is a mechanism for the chemopreventive activity of bisphosphonates and that it represents a new strategy for preventing colon cancer induced by intestinal commensals.

Role of immunohistochemical markers in predicting progression of dysplasia to advanced neoplasia in patients with ulcerative colitis

BACKGROUND

Although dysplasia is thought to be the precursor lesion in the development of colitis-associated colorectal cancer (CRC), a significant proportion of patients with ulcerative colitis (UC) and low-grade (LGD) or indefinite (IND) dysplasia remain cancer-free during endoscopic follow-up. There is a need for biomarkers that predict neoplastic progression. We studied the value of a series of immunohistochemical markers in UC patients with flat LGD or IND with regard to neoplastic progression.

METHODS

Tissue samples were collected from 12 UC patients (six flat LGD, six IND) without progression and from 10 UC patients (eight flat LGD, two IND) with documented progression to HGD and/or CRC during a median of 25 and 23 months of colonoscopic follow-up, respectively. Immunohistochemistry using monoclonal antibodies was performed for p53, CD44, Ki67, AMACR, β-catenin, cyclin D1, p21, and ALDH. Positive and negative staining patterns were compared for progression to advanced neoplasia.

RESULTS

When patients showed coexpression of p53 and AMACR, 6/7 patients (86%) developed advanced neoplasia, compared to 4/15 patients (27%) without p53/AMACR coexpression (P = 0.02). Patients with p53/AMACR coexpression developed advanced neoplasia in a time period of 19 months (median, range 1-101) compared to 80 months (median, range 8-169) in patients without p53/AMACR coexpression (P = 0.14). Interestingly, in three patients with progression and previous dysplasia-negative biopsies, two out of three biopsies were p53-positive a median of 12 months (range 10-14) before the LGD/IND diagnosis.

CONCLUSIONS

This study suggests a role for p53/AMACR coexpression as a potential marker of neoplastic progression in patients with UC.

Cancer risk in IBD: How to diagnose and how to manage DALM and ALM

The risk of developing neoplasia leading to colorectal cancer is significantly increased in ulcerative colitis (UC) and most likely in Crohn’s disease. Several endoscopic surveillance strategies have been implemented to identify these lesions. The main issue is that colitis-associated neoplasms often occurs in flat mucosa, often being detected on taking random biopsies rather than by identification of these lesions via endoscopic imaging. The standard diagnostic procedure in long lasting UC is to take four biopsies every 10 cm. Image enhancement methods, such as chromoendoscopy and virtual histology using endomicroscopy, have greatly improved neoplasia detection rates and may contribute to reduced random biopsies by taking targeted “smart” biopsies. Chromoendoscopy may effectively be performed by experienced endoscopists for routine screening of UC patients. By contrast, endomicroscopy is often only available in selected specialized endoscopic centers. Importantly, advanced endoscopic imaging has the potential to increase the detection rate of neoplasia whereas the interplay between endoscopic experience and interpretation of histological biopsy evaluation allows the physician to make a proper diagnosis and to find the appropriate therapeutic approach. Colitis-associated intraepithelial neoplasms may occur in flat mucosa of endoscopically normal appearance or may arise as dysplasia-associated lesion or mass (DALM), which may be indistinguishable from sporadic adenomas in healthy or non-colitis mucosa [adenoma-like mass (ALM)]. The aim of this review was to summarize endoscopic and histological characteristics of DALM and ALM in the context of therapeutic procedures.

Invasive behavior of ulcerative colitis-associated carcinoma is related to reduced expression of CD44 extracellular domain: comparison with sporadic colon carcinoma

Background

To elucidate relations of invasion of ulcerative colitis (UC)-associated carcinoma with its prognosis, the characteristics of invasive fronts were analyzed in comparison with sporadic colonic carcinomas.

Methods

Prognoses of 15 cases of UC-associated colonic carcinoma were compared with those of sporadic colon carcinoma cases, after which 75 cases of sporadic invasive adenocarcinoma were collected. Tumor budding was examined histologically at invasive fronts using immunohistochemistry (IHC) of pancytokeratin. Expressions of beta-catenin with mutation analysis, CD44 extracellular domain, Zo-1, occludin, matrix matalloproteinase-7, laminin-5γ2, and sialyl Lewis X (Le^X) were immunohistochemically evaluated.

Results

UC-associated carcinoma showed worse prognosis than sporadic colon carcinoma in all the cases, and exhibited a tendency to become more poorly differentiated when carcinoma invaded the submucosa or deeper layers than sporadic carcinoma. When the lesions were compared with sporadic carcinomas considering differentiation grade, reduced expression of CD44 extracellular domain in UC-associated carcinoma was apparent. Laminin-5γ2 and sialyl-Le^X expression showed a lower tendency in UC-associated carcinomas than in their sporadic counterparts. There were no differences in the numbers of tumor budding foci between the two lesion types, with no apparent relation to nuclear beta-catenin levels in IHC.

Conclusions

UC-associated carcinoma showed poorer differentiation when the carcinoma invaded submucosa or deeper parts, which may influence the poorer prognosis. The invasive behavior of UC-associated carcinoma is more associated with CD44 cleavage than with basement membrane disruption or sialyl-Lewis-antigen alteration.

The AOM/DSS murine model for the study of colon carcinogenesis: From pathways to diagnosis and therapy studies

Colorectal cancer (CRC) is a major health problem in industrialized countries. Although inflammation-linked carcinogenesis is a well accepted concept and is often observed within the gastrointestinal tract, the underlying mechanisms remain to be elucidated. Inflammation can indeed provide initiating and promoting stimuli and mediators, generating a tumour-prone microenvironment. Many murine models of sporadic and inflammation-related colon carcinogenesis have been developed in the last decade, including chemically induced CRC models, genetically engineered mouse models, and xenoplants. Among the chemically induced CRC models, the combination of a single hit of azoxymethane (AOM) with 1 week exposure to the inflammatory agent dextran sodium sulphate (DSS) in rodents has proven to dramatically shorten the latency time for induction of CRC and to rapidly recapitulate the aberrant crypt foci–adenoma–carcinoma sequence that occurs in human CRC. Because of its high reproducibility and potency, as well as the simple and affordable mode of application, the AOM/DSS has become an outstanding model for studying colon carcinogenesis and a powerful platform for chemopreventive intervention studies. In this article we highlight the histopathological and molecular features and describe the principal genetic and epigenetic alterations and inflammatory pathways involved in carcinogenesis in AOM/DSS–treated mice; we also present a general overview of recent experimental applications and preclinical testing of novel therapeutics in the AOM/DSS model.

Role of different inflammatory and tumor biomarkers in the development of ulcerative colitis-associated carcinogenesis

BACKGROUND

Colorectal cancer (CRC) is the most severe complication in inflammatory bowel disease (IBD). In the present study we investigated different mechanistic links between chronic colonic inflammation and its progression to adenocarcinoma. Along these lines, given that adrenomedullin (AM) has been implicated in carcinogenesis, we also analyzed changes in its colonic expression.

METHODS

Mice were exposed to 5, 10, and 15 cycles of dextran sulfate sodium (DSS); each cycle consisted of 0.7% DSS for 1 week followed by distilled water for 10 days. After each period, macroscopic and histological studies, as well as characterization of inflammatory and tumor biomarkers, were carried out.

RESULTS

The disease activity index (DAI) showed that the disease was present from the third cycle and it gradually increased during the course of DSS treatment. Macroscopic tumors were only seen after 15 cycles, and microscopic study showed that inflammation, dysplasia, and adenocarcinomas correlated with DSS cycles. β-Catenin and proliferating cell nuclear antigen expressions progressively increased in animals treated with the different cycles of DSS. TNF-α and IFN-γ showed the highest production at the tenth cycle. COX-2, mPGES-1, and iNOS levels were also appreciably higher at the fifth and tenth cycles. Moreover, we observed a progressive enhancement in AM expression and changes in its intracellular location during the progression of the disease.

CONCLUSIONS

Our results show an early induction of proinflammatory factors, which may contribute to the development of colon cancer, as well as demonstrate, for the first time, the expression of AM in IBD-derived CRC.

Expression of standard CD44 in human colorectal carcinoma: association with prognosis

The aim of the present study was to evaluate the expression of standard CD44 (CD44s) in colorectal cancer (CRC), its relationship with clinicopathological characteristics, and its potential prognostic significance. CD44s levels were measured on immunohistochemistry in tumors and surrounding normal mucosa from 74 patients with primary colorectal carcinomas. The patients were followed for a median period of 37 months. Expression of CD44s in primary tumor and surrounding normal mucosa tissues was demonstrated in 100% (74/74) and 37.9% (28/74), respectively. The expression of CD44s in tumors was significantly associated with the depth of invasion (P = 0.034) and lymph node involvement (P = 0.031). A significant difference was observed between the overall survival and level of tumor CD44s expression, especially for stage IV carcinoma (P = 0.038). Multivariate analysis indicated that TNM stage (P = 0.020) and tumor CD44s expression (P = 0.008) were independent predictors of overall survival in adenocarcinomas. CD44s overexpression may be an independent unfavorable prognostic factor for overall survival in advanced CRC, especially stage IV disease. Further investigation, however, is necessary to assess the biological roles of CD44 in CRC, and validate their possible value as novel therapeutic targets.

Nuclear β-catenin expression as a prognostic factor in advanced colorectal carcinoma

AIM: To investigate the changing pattern of β-catenin expression and its prognostic value in advanced colorectal cancer (CRC).

METHODS: Archival tumor samples were analyzed for β-catenin using immunohistochemistry (IHC) in 95 patients with advanced CRC.

RESULTS: Membranous β-catenin expression was found in the normal colorectal epithelium. Almost 100% of CRC cases showed membranous and cytoplasmic expression, and 55 (58%) cases showed nuclear expression. In univariate (Kaplan-Meier) survival analysis, only the nuclear index (NI) was a significant predictor of disease-free survival (DFS) (P = 0.023; n = 35), with a NI above the median associated with longer DFS (34.2 mo) than those with a NI below the median (15.5 mo) (P = 0.045, ANOVA). The other indices were not significant predictors of DFS, and none of the three tested indices (for membranous, cytoplasmic, or nuclear expression) predicted disease-specific survival (DSS). However, when dichotomized as positive or negative nuclear expression, the former was a significant predictor of more favorable DFS (P = 0.041) and DSS (P = 0.046).

CONCLUSION: Nuclear β-catenin expression provides additional information in predicting patient outcome in advanced CRC.

Wnt pathway-related gene expression in inflammatory bowel disease

The purpose of this study was to examine the expression of Wnt pathway-related genes in patients with ulcerative colitis (UC). RNA from colonoscopic biopsies from noninflammatory bowel disease (non-IBD) subjects and UC patients were obtained and examined with a Wnt-specific microarray for the expression of Wnt pathway-related genes. Paired samples from uninflamed and inflamed areas of the colon were obtained for the UC patients. WNT2B, WNT3A, WNT5B, WNT6, WNT7A, WNT9A, and WNT11 exhibited significantly increased expression in UC compared to non-IBD patients. Frizzled 3 (FZD3) and FZD4 exhibited significantly increased expression, and FZD1 and FZD5 exhibited significantly decreased expression in UC patients. Genes with increased expression in inflamed mucosa included DKK4, DVL2, SOX17, and COL1A1. There was no difference in the expression of a panel of Wnt target genes. The expression of inducible nitric oxide synthase (INOS) was variably influenced by inflammation. Significant differences in extracellular and cell-surface components of the Wnt pathway exist in the colonic mucosa of patients with UC compared with non-IBD patients, which may influence the strength or specificity of Wnt signaling. In inflammation, inhibitory components of the Wnt pathway exhibit increased expression, but no changes in Wnt pathway target gene expression are seen. The role and complex regulation of Sox17 and iNOS in IBD warrant further investigation.

Bench to bedside and back again: molecular mechanisms of alpha-catenin function and roles in tumorigenesis

The cadherin/catenin complex, comprised of E-cadherin, beta-catenin and alpha-catenin, is essential for initiating cell-cell adhesion, establishing cellular polarity and maintaining tissue organization. Disruption or loss of the cadherin/catenin complex is common in cancer. As the primary cell-cell adhesion protein in epithelial cells, E-cadherin has long been studied in cancer progression. Similarly, additional roles for beta-catenin in the Wnt signaling pathway has led to many studies of the role of beta-catenin in cancer. Alpha-catenin, in contrast, has received less attention. However, recent data demonstrate novel functions for alpha-catenin in regulating the actin cytoskeleton and cell-cell adhesion, which when perturbed could contribute to cancer progression. In this review, we use cancer data to evaluate molecular models of alpha-catenin function, from the canonical role of alpha-catenin in cell-cell adhesion to non-canonical roles identified following conditional alpha-catenin deletion. This analysis identifies alpha-catenin as a prognostic factor in cancer progression.

Pathology of dysplasia and cancer in inflammatory bowel disease

Morphologic identification of dysplasia in mucosal biopsies is the best and most reliable marker of an increased risk for malignancy in patients who have inflammatory bowel disease, and it forms the basis of the recommended endoscopic surveillance strategies that are in practice for patients who have this illness. In ulcerative colitis (UC) and Crohn's disease (CD), dysplasia is defined as unequivocal neoplastic epithelium that is confined to the basement membrane, without invasion into the lamina propria. Unfortunately, unlike in UC, only a few studies have evaluated the pathologic features and biologic characteristics of dysplasia and carcinoma in CD specifically. As a result, this article focuses mainly on the pathologic features, adjunctive diagnostic methods, and differential diagnosis of dysplasia in UC.

Prognostic value of E-cadherin, beta-catenin, MMPs (7 and 9), and TIMPs (1 and 2) in patients with colorectal carcinoma

BACKGROUND AND OBJECTIVES

Therapy of colorectal tumors (CRC) based on histology and clinical factors is insufficient to predict the evolution of each patient. The finding of molecular abnormalities able to differentiate subgroups of patients with bad prognosis will improve our ability to treat them successfully. Our purpose was to analyze retrospectively the prognostic input of E-cadherin, beta-catenin, metalloproteinases (MMPs) (7 and 9), and tissue inhibitors of metalloproteinases (TIMPs) (1 and 2) in patients with a follow-up period of 5 years.

METHODS

Antigen expression was analyzed by immunohistochemistry. Prognostic evaluation was performed with the multivariate proportional hazards model.

RESULTS

We demonstrated a concomitant loss of E-cadherin and beta-catenin at membranous level and an abnormal accumulation of nuclear beta-catenin. Besides, we found that all MMPs and TIMPs studied were overexpressed in CRC tissue. There was no association between the expression of any of these molecules and the known clinical-pathological parameters employed in CRC pathology. A multivariate analysis demonstrated that the overall survival could be independently predicted by the loss of E-cadherin and the overexpression of TIMP-2.

CONCLUSIONS

The expression of E-cadherin and TIMP-2 could be relevant in determining the prognosis of CRC patients and providing a more accurate mechanism for their classification.

Bottom-up cell proliferation with cyclin A and p27Kip1 expression in ulcerative colitis-associated dysplasia

To analyze the cell kinetics of ulcerative colitis (UC)-associated dysplasia, cyclin A, cyclin D1, cyclin E, cdk2, cdk4, p21(Waf1), and p27(Kip1) were immunohistochemically examined, in comparison with sporadic tubular adenomas. Immunohistochemical labeling indices for each marker in formalin-fixed paraffin-embedded tissue sections were assessed in a total of 23 low-grade dysplasias, 27 high-grade dysplasias, and 14 invasive adenocarcinomas associated with UC. For comparison, 21 sporadic tubular adenomas with low-grade dysplasia, 33 with high-grade dysplasia, and 21 invasive adenocarcinomas were also examined. In UC-associated dysplasias, cyclin A and p27(Kip1) were located in the lower parts of the crypts and p21(Waf1) in the upper regions. In tubular adenomas, cyclin A, cdk4, p27(Kip1), and p21(Waf1) were all expressed in the upper parts of the crypts. The expression levels of cyclin D1, cyclin E, and cdk2 were low. The cell proliferation zone in UC-associated dysplasia is located towards the bases of the crypts with the strong expression of cyclin A and p27(Kip1), in contrast to tubular adenomas, which have their cell proliferation zone in the upper parts of neoplastic crypts. It is considered that tumorigenesis with UC-associated dysplasia is of the bottom-up type, related to altered expression of cyclin A and p27(Kip1).

A relação da caderina-E com o prognóstico do adenocarcinoma colorretal

OBJETIVO: Avaliar a relação da expressão da caderina-E com o intervalo livre de doença (ILD), com a sobrevida (S) e com o estadiamento de doentes operados por adenocarcinoma colorretal. MÉTODO: Foram estudados 89 doentes (41 homens e 48 mulheres) com média de idade de 62,3 anos. A distribuição segundo o estadiamento TNM foi: estádio I - 13 (14,6%) doentes, estádio II - 29 (32,6%), estádio III - 23 (25,8%) e estádio IV - 24 (27,0%). Sessenta e sete doentes foram submetidos à operação radical e acompanhados por um período médio de 37,9 meses. Os tumores foram examinados por técnica imuno-histoquímica e classificados como positivos ou negativos em relação à expressão da caderina-E. RESULTADOS: A caderina-E foi positiva em 49,4% e negativa em 50,6% dos doentes. A recidiva ocorreu em 22,4% dos doentes e não esteve relacionada à expressão da caderina-E. Não foi observada relação da caderina- E com intervalo livre de doença e com a sobrevida. Também não foi verificada a associação da caderina-E (p = 0,958) com o estadiamento TNM. CONCLUSÃO: Os resultados verificados nesta pesquisa não permitem relacionar a expressão tissular da caderina-E com o estadiamento e o prognóstico do adenocarcinoma colorretal.

Expression of cell adhesion molecules, CD44s and E-cadherin, and microvessel density in invasive micropapillary carcinoma of the breast

AIMS

Invasive micropapillary carcinoma (IMPC) is a rare variant of ductal carcinoma of the breast and is characterized by high metastatic potential and an aggressive clinical course. This tumour is hence ideal for studying the mechanism underlying tumour biological behaviour, especially metastasis. Cell adhesion molecules, such as CD44 and E-cadherin (Ecad), and angiogenesis are considered important in the invasion and metastasis of tumours.

METHODS AND RESULTS

We immunohistochemically analysed 23 IMPCs for expression of a standard form of CD44 (CD44s), Ecad, and CD34 to measure microvessel density (MVD). Results are compared with the changes observed in 23 tubular carcinomas (TCs), another variant of ductal carcinoma that rarely metastasizes. Evaluation of haematoxylin and eosin (H&E) sections showed a higher prevalence of lymph-vascular invasion (19/23, 83%) and regional lymph node involvement (12/15, 80%) in IMPCs; whereas no lymph-vascular invasion or lymph node metastasis was identified in TCs. Loss or reduction of CD44s immunoreactivity was significantly frequent in IMPC (39%) compared with TC (4%) (P = 0.0098), and was associated with positive axillary lymph nodes and lymph-vascular invasion. All cases of IMPC and TC strongly expressed Ecad. MVD (in five 200x fields) was significantly higher in IMPC (88 +/- 37) than in TC (57 +/- 16) (P = 0.001). In the IMPC group, MDV was higher in cases with positive lymph node(s) (P = 0.048), and cases with loss or reduction of CD44s expression (P = 0.011). The same trend was also demonstrated in cases with lymph-vascular invasion (P = 0.077). Moreover, the vessels in IMPC had much smaller calibres with thinner walls than those in TC.

CONCLUSIONS

Loss of the CD44 adhesion molecule and high MVD may play a significant role in the high incidence of lymph-vascular permeation and metastasis in IMPC.

Beta-Catenin mutations in a mouse model of inflammation-related colon carcinogenesis induced by 1,2-dimethylhydrazine and dextran sodium sulfate

In a previous study, we developed a novel mouse model for colitis-related carcinogenesis, utilizing a single dose of azoxymethane (AOM) followed by dextran sodium sulfate (DSS) in drinking water. In the present study, we investigated whether colonic neoplasms can be developed in mice initiated with a single injection of another genotoxic colonic carcinogen 1,2-dimethylhydrazine (DMH), instead of AOM and followed by exposure of DSS in drinking water. Male crj: CD-1 (ICR) mice were given a single intraperitoneal administration (10, 20 or 40 mg/kg body weight) of DMH and 1-week oral exposure (2% in drinking water) of a non-genotoxic carcinogen, DSS. All animals were killed at week 20, histological alterations and immunohistochemical expression of beta-catenin, cyclooxygenase (COX-2) and inducible nitric oxide synthase (iNOS) were examined in induced colonic epithelial lesions (colonic dysplasias and neoplasms). Also, the beta-catenin gene mutations in paraffin-embedded colonic adenocarcinomas were analyzed by the single strand conformation polymorphism method, restriction enzyme fragment length polymorphism and direct sequencing. The incidences of colonic neoplasms with dysplastic lesions developed were 100% with 2.29+/-0.95 multiplicity, and 100% with 10.38+/-4.00 multiplicity in mice given DMH at doses of 10 mg/kg or 20 mg/kg and 2%DSS, respectively. Although approximately half of the mice given DMH at a dose of 40 mg/kg bodyweight were dead after 2-3 days after the injection, mice who received DMH 40 mg/kg and 2%DSS had 100% incidence of colonic neoplasms with 9.75+/-6.29 multiplicity. Immunohistochemical investigation revealed that adnocarcinomas, induced by DMH at all doses and 2%DSS, showed positive reactivities against beta-catenin, COX-2 and iNOS. In DMH/DSS-induced adenocarcinomas, 10 of 11 (90.9%) adenocacrcinomas had beta-catenin gene mutations. Half of the mutations were detected at codon 37 or 41, encoding serine and threonine that are direct targets for phosphorylation by glycogen synthase kinase-3beta. The present results suggests that, as in the previously reported model (AOM/DSS) our experimental protocol, DMH initiation followed by DSS, may provide a novel and useful mouse model for investigating inflammation-related colon carcinogenesis and for identifying xenobiotics with modifying effects.

Upregulation of p16(INK4A) and Bax in p53 wild/p53-overexpressing crypts in ulcerative colitis-associated tumours

In ulcerative colitis (UC)-associated tumours, p53 gene mutations and p53 protein overexpression are frequently found in early stages, but the two types of alteration do not always coincide. To clarify this discrepancy, p53 mutations and expression of p53-associated molecules were analysed in UC-associated dysplasias by a combination of microdissection, polymerase chain reaction-direct sequencing and immunohistochemistry at the single crypt level. Mismatch of p53 protein overexpression (+)/mutation (−) or p53 overexpression (−)/gene mutation (+) was found in nine crypts in regenerative mucosa (19 crypts), in 27 in low-grade dysplasia (41), in one in high-grade dysplasia (5) and in 12 in invasive carcinomas (17). Regarding these mismatched crypts of the first type, significant increase in p16^INK4A and Bax expression was found. The Ki-67 labelling index was depressed in such p53-diffusely positive lesions with the wild-type p53 gene, compared to their p53-diffusely positive and mutant type counterparts. p16^INK4A was upregulated indirectly as part of the negative feedback, and increase in Bax, directly controlled by wild-type p53, indicates upregulation of apoptosis. No significant relation with p53-related gene products was detected with the p53 protein overexpression (−)/p53 mutation (+) mismatch. Therefore, a tumorigenesis pathway independent of p53 dysfunction appears to exist in association with ulcerative colitis.

A novel inflammation-related mouse colon carcinogenesis model induced by azoxymethane and dextran sodium sulfate

To develop an efficient animal model for colitis-related carcinogenesis, male Crj: CD-1 (ICR) mice were given a single intraperitoneal administration (10 mg/kg body weight) of a genotoxic colonic carcinogen, azoxymethane (AOM), and a 1-week oral exposure (2% in drinking water) to a non-genotoxic carcinogen, dextran sodium sulfate (DSS), under various protocols. At week 20, colonic neoplasms (adenocarcinomas, 100% incidence with 5.60 +/- 2.42 multiplicity; and adenomas, 38% incidence with 0.20 +/- 0.40 multiplicity) with dysplastic lesions developed in mice treated with AOM followed by DSS. Protocols in which AOM was given during or after DSS administration induced a few tubular adenomas or no tumors in the colon. Immunohistochemical investigation of such dysplasias and neoplasms revealed that all lesions were positive for beta-catenin, cyclooxygenase-2 and inducible nitric oxide synthase, but did not show p53 immunoreactivity. The results indicate that 1-week administration of 2% DSS after initiation with a low dose of AOM exerts a powerful tumor-promoting activity in colon carcinogenesis in male ICR mice, and may provide a novel mouse model for investigating colitis-related colon carcinogenesis and for identifying xenobiotics with modifying effects.

CD44 in cancer

CD44 is a multistructural and multifunctional cell surface molecule involved in cell proliferation, cell differentiation, cell migration, angiogenesis, presentation of cytokines, chemokines, and growth factors to the corresponding receptors, and docking of proteases at the cell membrane, as well as in signaling for cell survival. All these biological properties are essential to the physiological activities of normal cells, but they are also associated with the pathologic activities of cancer cells. Experiments in animals have shown that targeting of CD44 by antibodies, antisense,and CD44-soluble proteins markedly reduces the malignant activities of various neoplasms, stressing the therapeutic potential of anti-CD44 agents. Furthermore, because alternative splicing and posttranslational modifications generate many different CD44 sequences, including, perhaps, tumor-specific sequences, the production of anti-CD44 tumor-specific agents may be a realistic therapeutic approach. However, in many cancers (renal cancer and non-Hodgkin's lymphomas are exceptions), a high level of CD44 expression is not always associated with an unfavorable outcome. On the contrary, in some neoplams CD44 upregulation is associated with a favorable outcome. Even worse, in many cases different research grows analyzing the same neoplastic disease reached contradictory conclusions regarding the correlation between CD44 expression and disease prognosis, possibly due to differences in methodology. These problems must be resolved before applying anti-CD44 therapy to human cancers.

High resolution analysis of chromosome 18 alterations in ulcerative colitis-related colorectal cancer

We previously have demonstrated by comparative genomic hybridization that 80% of ulcerative colitis-related cancers show loss of all or part of chromosome 18, the site of at least three candidate tumor suppressor genes: DCC, SMAD2, and SMAD4. To determine whether these genes are targeted in colitis-related carcinogenesis, we performed a high-resolution analysis of chromosome 18 alteractions in 32 colitis-related colorectal cancers by assessing allelic imbalance at 11 microsatellite markers distributed along the chromosome, and by the quantitative polymerase chain reaction (PCR) method (TaqMan). TaqMan analysis was used to determine the relative copy number of five test genes on chromosome 18 (PACAP on 18p and DCC, SMAD2, SMAD4, and GALNR on 18q). We found allelic imbalance, as assessed by loss of heterozygosity, in at least one marker on chromosome 18 in 25 of the 29 tumors (86%) successfully tested. In 14 tumors, allelic imbalance was detected at all informative markers on 18q, while the other 11 tumors showed only partial loss. Allelic imbalance was most commonly detected at D18S363 (78% of informative cases). This marker is in closest proximity to SMAD4. By quantitative PCR analysis, a relative loss of copy number of SMAD2, SMAD4, and DCC were detected in 40%, 57%, and 53%, respectively, of the colitis-related cancers. SMAD2 was retained in four tumors having loss of SMAD4 and DCC. Loss of SMAD4 alone was seen in one tumor. The present data indicate that the loss of SMAD4 and DCC occurs in the majority of colitis-related cancers.

Colorectal cancer in inflammatory bowel disease: molecular and clinical features

The two forms of inflammatory bowel disease (IBD), Crohn's disease and ulcerative colitis, are characterized by chronic and relapsing inflammation of the intestines. Initiating events presumably occur well before patients are symptomatic. Evidence gathered over the past decade from both IBD patients and animal models of intestinal inflammation have confirmed that IBD represents complex heterogenic forms of diseases, influenced by a combination of environmental, genetic, and immunologic factors working in concert to produce exaggerated immune responses, resulting in chronic and remitting inflammation.