Analysis of Snail-1, E-cadherin and claudin-1 expression in colorectal adenomas and carcinomas

Expression of Claudins in Preneoplastic Conditions of the Gastrointestinal Tract: A Review

Premalignant lesions of the gastrointestinal tract are a group of disorders which act as the harbinger of malignant tumors. They are the ground-zero of neoplastic transformation, and their identification and management offer patients the best opportunity of blocking the progress of cancer. However, diagnoses of some of these conditions are hard to make, and their clinical importance is difficult to assess. Recent reports indicated that several claudin proteins have altered expressions in many cancers, including esophageal, gastric, colon, liver, and pancreatic cancers. The early identification of the aberrant expression of these proteins could lead to the early diagnosis and management of gastrointestinal tumors. Specifically, claudins -1, -2, -3, -4, and -18 are frequently overexpressed in gastrointestinal preneoplastic lesions. These altered expressions have shown clinical value in several tumors, providing diagnostic and prognostic information. In this article, we review the literature on the aberrant expression of claudins in preneoplastic lesions of the gastrointestinal tract. Additionally, we summarize their diagnostic and prognostic implications.

Claudins: The Newly Emerging Targets in Breast Cancer

Claudin-low breast cancers are recently described entities showing low expression of certain claudins and cell adhesion molecules. Claudins constitute the backbone of tight junctions (TJs) formed between 2 cells. Their dysregulation plays a vital role in tumorigenesis. First part of the article focuses on the role of claudins in the TJ organization, their structural-functional characteristics, and post-transcriptional and translational modifications. The latter part of the review attempts to summarize existing knowledge regarding the status of claudins in breast cancer. The article also provides an overview of the effect of claudins on tumor progression, metastasis, stemness, chemotherapy resistance, and their crosstalk with relevant signaling pathways in breast cancer. Claudins can act as 2-edged swords in tumors. Some claudins have either tumor-suppressive/ promoting action, while others work as both in a context-dependent manner. Claudins regulate many important events in breast cancer. However, the intricacies involved in their activity are poorly understood. Post-translational modifications in claudins and their impact on TJ integrity, function, and tumor behavior are still unclear. Although their role in adverse events in breast cancer is recognized, their potential to serve as relevant targets for future therapeutics, especially for difficult-to-treat subtypes of the above malignancy, remains to be explored.

Immunohistochemical expression of Snail1 protein in colorectal adenocarcinoma samples and its prognostic activity in Caucasian patients

Introduction

The current study investigated the expression of Snail1 protein in colon adenocarcinoma samples to assess its prognostic significance by correlating its expression with the clinicopathological variables and survival of Caucasian patients.

Aim

To investigate the clinicopathological and prognostic roles of Snail1 expression, the immunohistochemical analysis was performed in colon tumour tissues and adjacent non- pathological mucosa.

Material and methods

It should be noted that only trace expression of this protein was revealed in adjacent non-tumour colorectal mucosa, whereas the high expression was demonstrated in well differentiated, moderately differentiated, and poorly differentiated tumours.

Results

The Kaplan-Meier survival analysis showed that the overall survival rate in the group of patients with a low expression level of Snail1 was significantly longer than that for patients with a moderate or strong level of Snail1 immunoreactivity (p < 0.001). The 5-year overall survival for patients with a low, moderate, or strong level of Snail1 immunoexpression was 100%, 25.7%, and 2%, respectively. The Snail1-moderate patients had an average survival time of 44.886 months (95% CI: 40.855–48.916), whereas the Snail1-strong expression groups had an average survival time of 21.706 (95% CI: 17.863–25.549). The statistical analysis revealed that the level of the Snail1 immunohistochemical reactivity was correlated with the grade of the histological differentiation. A multivariate analysis demonstrated that the grade of tumour differentiation (HR = 2.150; 95% CI: 1.380–3.349, p = 0.001) and Snail1 expression (HR = 3.901; 95% CI: 2.436–6.247, p < 0.001) were the independent risk factors for worse survival.

Conclusions

In colon adenocarcinoma patients, the expression of Snail1 may act as the independent risk factors for worse survival.

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.

Expression of Claudin-1 in laryngeal squamous cell carcinomas (LSCCs) and its significance

BACKGROUND

A large body of scientific evidence points to the important roles of tight junction proteins in tumor development, progression and dissemination. The larynx has only a few studies, analyzing the role of this group of junctional proteins in its oncogenesis. In this study, the author sheds some light on the expression and possible role of claudin-1 in laryngeal squamous cell carcinomas.

MATERIALS AND METHODS

This study analyzed the expression of claudin-1, using immunohistochemistry, in a tissue microarray of 80 cases of laryngeal squamous cell cancers. Clinicopathological parameters were analyzed according to claudin-1 expression in the tissue microarray. Furthermore, the expression of slug/snail1, an Epithelial-Mesenchymal Transition (EMT) linked protein, was analyzed by immunohistochemistry in the same microarray, and the expressions of the two proteins were assessed for correlation.

RESULTS

A significant majority of laryngeal squamous cell cancers exhibited positive expression of claudin-1 proteins. The majority of those tumors expressed claudin-1 in their cytoplasm. The overall majority of those same tumors also exhibited a cytoplasmic shift of the slug-snail-1 protein from the nuclei to the cytoplasm. There was also evidence of correlation of the two proteins' expressions in the cytoplasm of laryngeal tumors.

CONCLUSION

The above may suggest a role for claudin-1 in the development and progression of laryngeal squamous cell carcinoma. Overall, claudin-1's aberrant expression in laryngeal cancer is in line with evidence seen in other head and neck cancers. Its co-expression with slug/snail-1 in LSCC patients should be investigated further to understand the nature of the relationship of the two proteins in LSCC and their possible contribution to its development and progression.

Identification of Radil as a Ras binding partner and putative activator

Ras genes are among the most frequently mutated oncogenes in human malignancies. To date, there are no successful anticancer drugs in the clinic that target Ras proteins or their pathways. Therefore, it is imperative to identify and characterize new components that regulate Ras activity or mediate its downstream signaling. To this end, we used a combination of affinity-pulldown and mass spectrometry to search for proteins that are physically associated with KRas. One of the top hits was Radil, a gene product with a Ras-association domain. Radil is known to be a downstream effector of Rap1, inhibiting RhoA signaling to regulate cell adhesion and migration. We demonstrate that Radil interacted with all three isoforms of Ras including HRas, NRas, and KRas, although it exhibited the strongest interaction with KRas. Moreover, Radil interacts with GTP-bound Ras more efficiently, suggesting a possibility that Radil may be involved in Ras activation. Supporting this, ectopic expression of Radil led to transient activation of mitogen-activated protein kinase kinase and extracellular signal-regulated kinase; Radil knockdown resulted in weakened activation of Ras downstream signaling components, which was coupled with decreased cell proliferation and invasion, and reduced expression of mesenchymal cell markers. Moreover, Radil knockdown greatly reduced the number of adhesion foci and depolymerized actin filaments, molecular processes that facilitate cancer cell migration. Taken together, our present studies strongly suggest that Radil is an important player for regulating Ras signaling, cell adhesion, and the epithelial–mesenchymal transition and may provide new directions for Ras-related anticancer drug development.

Cadherins down-regulation: towards a better understanding of their relevance in colorectal cancer

The down-regulation of cadherin expression in colorectal cancer (CRC) has been widely studied. However, existing data on cadherin expression are highly variable and its relevance to CRC development has not been completely established. This review examines published studies on cadherins whose down-regulation has been already demonstrated in CRC, trying to establish a relationship with promoter methylation, the capacity to influence the Wnt / CTNNB1 (catenin beta 1, beta-catenin) signalling pathway and the clinical implications for disease outcome. Moreover, it also analyses factors that may explain data variability and highlights the importance of considering the altered subcellular localization of the examined cadherins. The results of this survey reveal that thirty of one hundred existing cadherins appear to be down-regulated in CRC. Among these, ten are cadherins, sixteen are protocadherins, equally divided between clustered and non clustered, and four are cadherin - related. These findings suggest that, to better define the role played by cadherin down-regulation in CRC pathogenesis, the expression of multiple rather than individual cadherins should be taken into account and further functional studies are necessary to clarify the relative ability of individual cadherins to inhibit CTNNB1 therefore acting as tumor suppressors.

Epithelial-Mesenchymal Transition-Related MicroRNAs and Their Target Genes in Colorectal Cancerogenesis

MicroRNAs of the miR-200 family have been shown experimentally to regulate epithelial-mesenchymal transition (EMT). Although EMT is the postulated mechanism of development and progression of colorectal cancer (CRC), there are still limited and controversial data on expression of miR-200 family and their target genes during CRC cancerogenesis. Our study included formalin-fixed paraffin-embedded biopsy samples of 40 patients (10 adenomas and 30 cases of CRC with corresponding normal mucosa). Expression of miR-141, miR-200a/b/c and miR-429 and their target genes (CDKN1B, ONECUT2, PTPN13, RND3, SOX2, TGFB2 and ZEB2) was analysed using quantitative real-time PCR. Expression of E-cadherin was analysed using immunohistochemistry. All miRNAs were down-regulated and their target genes showed the opposite expression in CRC compared to adenoma. Down-regulation of the miR-200 family at the invasive front in comparison to the central part of tumour was observed as well as a correlation of expression of miR-200b, CDKN1B, ONECUT2 and ZEB2 expression to nodal metastases. Expression of the miR-200 family and SOX2 also correlated with E-cadherin staining. These results suggest that the miR-200 family and their target genes contribute to progression of adenoma to CRC, invasive properties and development of metastases. Our results strongly support the postulated hypotheses of partial EMT and intra-tumour heterogeneity during CRC cancerogenesis.

Expression and significance of PTEN and Claudin-3 in prostate cancer

Expression and significance of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and Claudin-3 in the blood of patients with prostate cancer [prostate cancer (PCa)] were investigated. Retrospective analysis of 84 cases of PCa patients confirmed by pathological diagnosis were studied, as the experiment group. Moreover, the physical examination data of 84 healthy volunteers examined in the Affiliated Hospital of Beihua University were the control group. The expression levels of blood in the PTEN and Claudin-3 of both the experiment group and the control group were determined by enzyme-linked immunosorbent assay. According to the blood expression in PTEN and Claudin-3 between both the experiment group and the control group, the test value of the ROC curve in PTEN and Claudin-3 were detected by both single detection and joint detection. The expression levels of PTEN in the experiment group were significantly lower than the control group (P<0.05). The expression levels of Claudin-3 were higher in the experiment group than the control group (P<0.01). The expression levels of PTEN and Claudin-3 in the experiment group were significantly associated with the distant metastasis of cancer cells, preoperative prostate-specific antigen levels, tumor diameter and pathological stages (P<0.01). The expression levels of PTEN in the pathological stage of T1-T2 group was lower than that of the T3-T4 group (P<0.01). The expression levels of PTEN and Claudin-3 are closely related to the distant metastasis of cancer cells, preoperative prostate-specific antigen level, tumor diameter and pathological stage. Combined detection of both PTEN and Claudin-3 can improve the specificity levels of PCa for diagnosis and has an important diagnostic value for PCa. It can be used as a biological indicator for PCa diagnosis, disease severity analysis and efficacy evaluation.

Targeting the Overexpressed YY1 in Cancer Inhibits EMT and Metastasis

There have been recent developments in the treatment of various cancers, in particular non-metastatic cancers. However, many of the responding patients often relapse initially through the development of spread micro and macro-metastases. Unfortunately, there are very few therapeutic modalities for the treatment of metastatic cancers. The development of cancer metastasis has been proposed to involve the epithelial-mesenchymal transition (EMT), in which the tumor cells with the EMT phenotype exhibit various phenotypic markers and molecular modifications that are manifested to resist most conventional therapies. YY1 is a target of the hyperactivated nuclear factor-kappa beta pathway in cancer and it was reported that YY1 also regulates cell survival and cell proliferation in addition to its role in EMT and resistance. The overexpression of YY1 in the majority of cancers has been correlated with poor prognosis. It is hypothesized that targeting YY1 may result in several anti-tumor activities, including inhibition of cell survival and cell proliferation, inhibition of EMT, and reversal of resistance. This review discusses the potential therapeutic targeting of an overexpressed transcription factor, Yin Yang 1 (YY1), which has been implicated in the development of EMT and drug resistance. Several examples targeting YY1 in experimental models are presented.

Therapeutic implications of cancer epithelial-mesenchymal transition (EMT)

The epithelial-mesenchymal transition (EMT) comprises an essential biological process involving cancer progression as well as initiation. While the EMT has been regarded as a phenotypic conversion from epithelial to mesenchymal cells, recent evidence indicates that it plays a critical role in stemness, metabolic reprogramming, immune evasion and therapeutic resistance of cancer cells. Interestingly, several transcriptional repressors including Snail (SNAI1), Slug (SNAI2) and the ZEB family constitute key players for EMT in cancer as well as in the developmental process. Note that the dynamic conversion between EMT and epithelial reversion (mesenchymal-epithelial transition, MET) occurs through variable intermediate-hybrid states rather than being a binary process. Given the close connection between oncogenic signaling and EMT repressors, the EMT has emerged as a therapeutic target or goal (in terms of MET reversion) in cancer therapy. Here we review the critical role of EMT in therapeutic resistance and the importance of EMT as a therapeutic target for human cancer.

Loss of claudin-1 expression induces epithelial-mesenchymal transition through nuclear factor-κB activation in colorectal cancer

OBJECTIVE

The aim of this study was to elucidate the clinicopathological significance and prognostic role of loss of claudin-1 in colorectal cancer (CRC).

METHODS

The correlations between claudin-1 expression and clinicopathological characteristics, including survival rates, were assessed using immunohistochemistry on 260 archival, paraffin-embedded CRC tissues. In addition, the correlations between cludin-1 and nuclear factor-kappa B (NF-κB), epithelial-mesenchymal transition markers and tumor-infiltrating lymphocytes were investigated.

RESULTS

Claudin-1 expression was markedly lost in 42.7% of the 260 CRCs analyzed. Loss of claudin-1 expression significantly correlated with larger tumor size, vascular invasion, higher pT stage, and high metastatic lymph node ratio. In addition, loss of claudin-1 expression significantly correlated with NF-κB activation (P < 0.001), high SNAI (P < 0.001), and low E-cadherin (P < 0.001) expressions. Patients with high immunoscores showed significantly lower rates of claudin-1 expression loss (P = 0.020). In detail, loss of claudin-1 expression were frequently found in CRCs low CD3- and CD8-positive lymphocytes. There were significant correlations between claudin-1 expression loss and poor overall and recurrence-free survivals (P < 0.001 and P < 0.001, respectively).

CONCLUSION

Taken together, our results suggest that the loss of claudin-1 expression significantly correlates with aggressive tumor behaviors, high SNAI expression, lower immunoscore, and poor prognoses.

Biological Aggressiveness of Subclinical No-Mass Ductal Carcinoma In Situ (DCIS) Can Be Reflected by the Expression Profiles of Epithelial-Mesenchymal Transition Triggers

Epithelial-mesenchymal transitions (EMTs) have been recently implicated in the process of cancer progression. The aim of this study was to assess how the preoperative expression patterns of EMT biomarkers correlate with the risk of postoperative invasion in ductal carcinoma in situ (DCIS) found on stereotactic breast biopsies. N-cadherin, Snail1, and secreted protein acidic and rich in cysteine (SPARC) immunoreactivity was observed in 8%, 62%, and 38% of tumors, respectively. Snail1 and SPARC expressions were significantly related to N-cadherin expression and to each other. The postoperative upgrading rate was associated with a positive preoperative expression of all biomarkers. Significance of Snail1 and SPARC persisted in multivariate analysis, but the impact of SPARC on invasion was more significant. When these two EMT triggers were considered together, the risk of invasion did not significantly differ between the subtypes of DCIS with single positive expression (SPARC−/Snail1+ vs. SPARC+/Snail1−). However, it was significantly lower in single-positive DCIS when compared to lesions of a double-positive profile (SPARC+/Snail1+). Moreover, there were no cases in the double-negative DCIS (SPARC−/Snail1−), with foci of infiltrating cancer found postoperatively in residual postbiopsy lesions. In contrast, DCIS with a combined high SPARC and Snail1 expression (intermediate or strong) had an invasive component in 66–100% of tumors.

Claudin-7 downregulation induces metastasis and invasion in colorectal cancer via the promotion of epithelial-mesenchymal transition

The dysregulation of the tight junctions (TJs) protein claudin-7 is closely related to the development and metastasis of colorectal cancer (CRC). The aim of this study was to investigate the expression of claudin-7 and characterize the relationship between claudin-7 expression and epithelial-mesenchymal transition (EMT) in CRC. In this study, the expression of claudin-7, E-cadherin, vimentin and snail-1 was detected by immunohistochemistry (IHC) in a set of 80 CRC specimens comprising 20 specimens each of well-differentiated, moderately differentiated, poorly differentiated and liver metastases tissues. The correlation between claudin-7 and EMT-related proteins in the stably transfected claudin-7 knockdown HCT116 cell line was analyzed by IHC, immunofluorescence (IF), Western blotting (WB) and nude mouse xenograft models. The results revealed that the expression of claudin-7 was downregulated as CRC tissue differentiation grade decreased, and that low claudin-7 expression corresponded to the downregulation of E-cadherin (r = 0.725, p < 0.001) and upregulation of vimentin (r = -0.376, p = 0.001) and snail-1 (r = -0.599, p < 0.001). Additionally, in the claudin-7 knockdown HCT116 cell line, the staining intensity and expression of E-cadherin was decreased, while the immunoreactivity and expression of vimentin and snail-1 was increased. Futhermore, the result of tumor formation experiment was consistent with CRC tissues. In conclusion, the expression of claudin-7 in CRC is downregulated as differentiation grade decreases. Claudin-7 downregulation may promote the invasion and metastasis of CRC by regulating EMT. Our results provide new perspectives for a potential therapeutic target for CRC.

Immunoreactivity patterns of tight junction proteins are useful for differential diagnosis of human salivary gland tumors

The expression pattern of tight junction proteins (TJPs) varies among organs and tumor types. In this study, we examined the immunoreactivity of claudin (CLDN)-1, -4, and -7, and JAM-A in salivary gland tumors (SGTs) by histological types and cell types to estimate their usefulness as differential diagnostic markers. Immunoreactivity of CLDN1 was higher in ductal epithelium cells of SGTs than in non-tumor tissues. Conversely, immunoreactivity of CLDN1 was significantly decreased in basal/myoepithelium cells of SGTs compared with that in non-tumor tissues. There was no significant difference between the immunoreactivity of CLDN1 in benign tumors and that in malignant tumors. Immunoreactivity of CLDN4, CLDN7, and JAM-A in ductal epithelium cells was higher in many SGTs than in non-tumor tissues. There was a difference depending on the histological type of SGT in immunoreactivity of CLDN4, CLDN7, and JAM-A in basaloid/myoepithelial cells. It was possible to classify SGTs by a hierarchical clustering using immunoreactivity of TJPs. The results suggest that an immunohistochemical marker panel including these TJPs may be useful for differential diagnosis of SGTs and that CLDN1 is associated with tumorigenesis of SGTs.

Peniciketal A, A Novel Spiroketal Compound, Exerts Anticancer Effects by Inhibiting Cell Proliferation, Migration and Invasion of A549 Lung Cancer Cells

BACKGROUND

Peniciketal A (Pe-A) is a spiroketal compound isolated from saline soil-derived fungus Penicillium raistrickii. However, its role for biological processes has not been clarified. In this study, we for the first time investigated the anticancer effects and the underlying mechanisms of Pe-A in A549 lung cancer cells. Metheds: Cell proliferation was tested by MTT assay and colony formation assay. Flow cytometry was performed to examine the cell cycle, apoptosis and mitochondrial membrane potential. Invasion and migration were analyzed using transwell assay and wound healing analysis. Immunofluorescence staining and western blotting were used to evaluate the protein expression.

RESULTS

Pe-A effectively inhibited proliferation, with IC50 values was 22.33 μM for 72 h. Mechanistic studies revealed that Pe-A caused cell cycle arrest at the G0-G1 phase by decreasing cyclinD1 expression and induced apoptosis through accelerating the mitochondrial apoptotic pathway. Moreover, Pe-A significantly inhibited A549 cell migration and invasion by reducing the protein levels of MMP-2 and MMP-9, while the Epithelial- Mesenchymal Transition (EMT) property was also changed. Importantly, Pe-A exhibited much lower toxicity towards L02, normal liver cells, and MRC5, normal fibroblast cells, compared to A549 cells.

CONCLUSION

Collectively, the current results indicate that Pe-A may offer effective potentials and insights for lung cancer treatment and drug design.

KCTD11 inhibits growth and metastasis of hepatocellular carcinoma through activating Hippo signaling

A lack of effective prognostic biomarkers and molecular targets is a serious problem in hepatocellular carcinoma. KCTD11, reported as a tumor suppressor, are still not well understood. In this study, KCTD11 was found low-expressed in HCC tissues and cell lines. The HCC patients with low expression of KCTD11 suggested shorter overall survival. We found KCTD11 inhibiting cell proliferation in vitro and tumor growth in vivo, by activating p21 and repressing cycle related proteins. KCTD11 also inhibited cell adhesion by decreasing CTGF and CLDN1. We found CTGF binding COL3A1 in HCCLM3, which might lead to reduction of COL3A1 expression. KCTD11 also inhibited cell migration and invasion in HCC, by repressing MMPs and EMT. We found the tumor suppression function of KCTD11 was at least partly through activating Hippo pathway in HCC. Base on the enhanced Hippo pathway, KCTD11 could activate p21 by stabilizing p53 or promoting the MST1/ GSK3β/p21 signaling in HCC. Overall, these results suggest that KCTD11 works as a tumor suppressor and owns prognostic and therapeutic potentials in HCC.

Urtica dioica extract suppresses miR-21 and metastasis-related genes in breast cancer

BACKGROUND

Breast cancer has a high prevalence among women worldwide. Tumor invasion and metastasis still remains an open issue that causes most of the therapeutic failures and remains the prime cause of patient mortality. Hence, there is an unmet need to develop the most effective therapeutic approach with the lowest side effects and highest cytotoxicity that will effectively arrest or eradicate metastasis.

METHODS

An MTT assay and scratch test were used to assess the cytotoxicity and migration effects of Urtica dioica on the breast cancer cells. The QRT-PCR was used to study the expression levels of miR-21, MMP1, MMP9, MMP13, CXCR4, vimentin, and E-cadherin.

RESULTS

The results of gene expression in tumoral groups confirmed the overexpression of miR-21, MMP1, MMP9, MMP13, vimentin, and CXCR4, and the lower expression of E-cadherin compared to control groups (P<0.05). Moreover, the results of the MTT assay show that Urtica dioica significantly inhibited breast cancer cell proliferation. Moreover, findings from the scratch assay exhibited the inhibitory effects of Urtica dioica on the migration of breast cancer cell lines.

CONCLUSION

Urtica dioica extract could inhibit cancer cell migration by regulating miR-21, MMP1, MMP9, MMP13, vimentin, CXCR4, and E-Cadherin. Moreover, our findings demonstrated that the extract could decrease miR-21 expression, which substantially lessens the overexpressed MMP1, MMP9, MMP13, vimentin, and CXCR4 and increases E-cadherin in the tumoral group.

Gadd45β silencing impaired viability and metastatic phenotypes in cholangiocarcinoma cells by modulating the EMT pathway

Growth arrest and DNA damage-inducible-β (Gadd45β) is a stress-response protein involved in a number of processes, including cell cycle control, DNA repair, survival and death control, and stress signaling, depending on its interactions. Gadd45β expression is dysregulated in numerous types of cancer, functioning as either a tumor promoter or a tumor suppressor. However, the functions of Gadd45β in cholangiocarcinoma (CCA), particularly in metastasis, has not been studied. The immunohistochemical analysis of Gadd45β expression revealed that 75% of histological specimens from patients with CCA expressed high levels of Gadd45β, and that high Gadd45β expression was associated with metastasis. The role of Gadd45β in CCA was examined using siRNA-mediated gene knockdown in HuCCA-1, a human CCA cell line established from a Thai patient. The effects of Gadd45β downregulation upon cell viability and death, invasion, migration, matrix metalloproteinase (MMP) activity and epithelial-mesenchymal transition (EMT) marker expression were investigated. Gadd45β knockdown impaired cell viability, which was associated with the induction of apoptosis. In addition, there was a marked reduction in invasion and migration, although MMP activity was unaffected. Impairment of these metastatic properties was accompanied by the decreased expression of EMT markers, including Slug, vimentin, claudin-1 and zona occludens protein 1, whereas E-cadherin expression was increased. The present study suggests that Gadd45β is involved in regulating the viability and the metastatic potential of CCA cells, which may be mediated by the modulation of the EMT pathway.

Epithelial-mesenchymal transition inducer Snail1 and invasive potential of intraductal breast cancer

BACKGROUND AND OBJECTIVES

Transcription factor Snail1 is a key inducer of epithelial-mesenchymal transition (EMT), a biological process implicated in the cancer progression and metastasis. The aim of the study was to investigate Snail1 expression in DCIS found on breast biopsy and assess its predictive value for the final invasion.

METHODS

A total of 209 patients with histologically diagnosed pure DCIS entered the study. Snail1 reactivity was evaluated with immunohistochemistry in tumor tissue from stereotactic vacuum-assisted biopsy of suspicious microcalcifications.

RESULTS

Snail1 staining was observed in 62% of tumors: weak, intermediate, and strong in 27%, 21%, and 14% of lesions, respectively. Positive Snail1 expression was significantly rarer in DCIS presenting as powdery microcalcifications, when compared with crushed stone-like and casting-type and was more common in DCIS with comedonecrosis. Correlation with other features was not significant. None of standard parameters significantly influenced the upgrading rate. In contrast, in uni- and multivariate analysis the risk of postoperative invasion was significantly associated with positive Snail1 immunoreactivity. Moreover, there was a significant stepwise increase of upgrading rate according to Snail1 expression in DCIS cells: weak 9%, intermediate 26%, and strong 55%, respectively.

CONCLUSIONS

Snail1 can reflect the invasive potential of DCIS and help identify its more aggressive subtypes.

Differential transcription profiles of long non-coding RNAs in primary human brain microvascular endothelial cells in response to meningitic Escherichia coli

Accumulating studies have indicated the influence of long non-coding RNAs (lncRNAs) on various biological processes as well as disease development and progression. However, the lncRNAs involved in bacterial meningitis and their regulatory effects are largely unknown. By RNA-sequencing, the transcriptional profiles of host lncRNAs in primary human brain microvascular endothelial cells (hBMECs) in response to meningitic Escherichia coli were demonstrated. Here, 25,257 lncRNAs were identified, including 24,645 annotated lncRNAs and 612 newly found ones. A total of 895 lncRNAs exhibited significant differences upon infection, among which 382 were upregulated and 513 were downregulated (≥2-fold, p < 0.05). Via bioinformatic analysis, the features of these lncRNAs, their possible functions, and the potential regulatory relationships between lncRNAs and mRNAs were predicted. Moreover, we compared the transcriptional specificity of these differential lncRNAs among hBMECs, human astrocyte cell U251, and human umbilical vein endothelial cells, and demonstrated the novel regulatory effects of proinflammatory cytokines on these differential lncRNAs. To our knowledge, this is the first time the transcriptional profiles of host lncRNAs involved in E. coli-induced meningitis have been reported, which shall provide novel insight into the regulatory mechanisms behind bacterial meningitis involving lncRNAs, and contribute to better prevention and therapy of CNS infection.

The role of Snail1 transcription factor in colorectal cancer progression and metastasis

Snail1 is a zinc-finger transcription factor, which plays a role in colorectal cancer development by silencing E-cadherin expression and inducing epithelialmesenchymal transition (EMT). During EMT tumour cells acquire a mesenchymal phenotype that is responsible for their invasive activities. Consequently, Snail1 expression in colorectal cancer is usually associated with progression and metastasis. Some studies revealed that about 77% of colon cancer samples display Snail1 immunoreactivity both in activated fibroblasts and in carcinoma cells that have undergone EMT. Therefore, expression of this factor in the stroma may indicate how many cells possess the abilities to escape from the primary tumour mass, invade the basal lamina and colonise distant target organs. Blocking snail proteins activity has the potential to avert cancer cell metastasis by interfering with such cellular processes as remodelling of the actin cytoskeleton, migration and invasion, which are clearly associated with the aggressive phenotype of the disease. Moreover, the link between factors from the snail family and cancer stem cells suggests that inhibitory agents may also prove their potency as inhibitors of cancer recurrence.

Expression Level of Genes Coding for Cell Adhesion Molecules of Cadherin Group in Colorectal Cancer Patients

Background

Colorectal Cancer (CRC) is one of the most frequently diagnosed neoplasms and also one of the main death causes. Cell adhesion molecules are taking part in specific junctions, contributing to tissue integrality. Lower expression of the cadherins may be correlated with poorer differentiation of the CRC, and its more aggressive phenotype. The aim of the study is to designate the cadherin genes potentially useful for the diagnostics, prognostics, and the treatment of CRC.

Material/Method

Specimens were collected from 28 persons (14 female and 14 male), who were operated for CRC. The molecular analysis was performed using oligonucleotide microarrays, mRNA used was collected from adenocarcinoma, and macroscopically healthy tissue. The results were validated using qRT-PCR technique.

Results

Agglomerative hierarchical clustering of normalized mRNA levels has shown 4 groups with statistically different gene expression. The control group was divided into 2 groups, the one was appropriate control (C1), the second (C2) had the genetic properties of the CRC, without pathological changes histologically and macroscopically. The other 2 groups were: LSC (Low stage cancer) and HSC (High stage cancer). Consolidated results of the fluorescency of all of the differential genes, designated two coding E-cadherin (CDH1) with the lower expression, and P-cadherin (CDH3) with higher expression in CRC tissue.

Conclusions

The levels of genes expression are different for several groups of cadherins, and are related with the stage of CRC, therefore could be potentially the useful marker of the stage of the disease, also applicable in treatment and diagnostics of CRC.

Restoration of the anti-proliferative and anti-migratory effects of 1,25-dihydroxyvitamin D by silibinin in vitamin D-resistant colon cancer cells

Colorectal carcinoma (CRC) is the third most common cancer in developed countries. A large fraction of cases are linked to chronic intestinal inflammation, with concomitant increased TNF-α release and elevated Snail1/Snail2 levels. These transcription factors in turn suppress vitamin D receptor (VDR) expression, resulting in loss of responsiveness to the protective anti-proliferative and anti-migratory effects of 1,25-dihydroxyvitamin D (1,25D). Experimental and epidemiologic evidence support the use of natural products to target CRC. Here we show that the flavonolignan silibinin reverses the TNF-α-induced upregulation of Snail1 and Snail2 in the 1,25D-resistant human colon carcinoma cells HT-29. These silibinin effects are accompanied by an increase in VDR levels; Snail1 overexpression reverses these silibinin effects. Silibinin also restores promoter activity from a vitamin D-response element (VDRE) reporter construct. While 1,25D had no significant effect on HT-29 and SW480-R cell proliferation and migration, co-treatment with silibinin restored 1,25D responsiveness. In addition, co-treatment with silibinin plus 1,25D decreased proliferation and migration at doses where silibinin alone had no effect. These findings demonstrate that this combination may present a novel approach to target CRC in conditions of chronic colonic inflammation.

Serum response factor accelerates the high glucose-induced Epithelial-to-Mesenchymal Transition (EMT) via snail signaling in human peritoneal mesothelial cells

Background

Epithelial-to-Mesenchymal Transition (EMT) induced by glucose in human peritoneal mesothelial cells (HPMCs) is a major cause of peritoneal membrane (PM) fibrosis and dysfunction.

Methods

To investigate serum response factor (SRF) impacts on EMT-derived fibrosis in PM, we isolated HPMCs from the effluents of patients with end-stage renal disease (ESRD) to analyze alterations during peritoneal dialysis (PD) and observe the response of PM to SRF in a rat model.

Results

Our results demonstrated the activation and translocation of SRF into the nuclei of HPMCs under extensive periods of PD. Accordingly, HPMCs lost their epithelial morphology with a decrease in E-cadherin expression and an increase in α-smooth muscle actin (α-SMA) expression, implying a transition in phenotype. PD with 4.25% glucose solution significantly induced SRF up-regulation and increased peritoneal thickness. In immortal HPMCs, high glucose (HG, 60 mmol/L) stimulated SRF overexpression in transformed fibroblastic HPMCs. SRF-siRNA preserved HPMC morphology, while transfection of SRF plasmid into HPMCs caused the opposite effects. Evidence from electrophoretic mobility shift, chromatin immunoprecipitation and reporter assays further supported that SRF transcriptionally regulated Snail, a potent inducer of EMT, by directly binding to its promoter.

Conclusions

Our data suggested that activation of SRF/Snail pathway might contribute to the progressive PM fibrosis during PD.

Claudin-1 Expression Is Elevated in Colorectal Cancer Precursor Lesions Harboring the BRAF V600E Mutation

BACKGROUND: Sessile serrated adenomas/polyps (SSA/P) are now recognised precursors of colorectal cancer (CRC) including cancers harbouring somatic BRAF (V600E) mutations. While the morphological diagnostic criteria of SSA/P have been established, distinguishing between small/early SSA/P and microvesicular hyperplastic polyps (MVHP) is challenging and may not be possible in routine practice. METHODS: Gene expression profiling of MVHP (n=5, all BRAF V600E wild-type) and SSA/P (n=5, all BRAF V600E mutant) samples was performed. Quantitative reverse transcription–polymerase chain reaction (qRT-PCR) and immunohistochemical analysis was performed to verify the expression of claudin 1 (CLDN1) in MVHP and SSA/P. RESULTS: Gene expression profiling studies conducted between MVHP and SSA/P identified CLDN1 as the most statistically significant differentially expressed gene (p<0.05). Validation with qRT-PCR confirmed an up-regulation of CLDN1 in BRAF V600E mutant polyps regardless of polyp type (p<0.0005). Immunohistochemical analysis of CLDN1 expression in BRAF V600E mutant SSA/Ps (n=53) and MVHPs (n=111) and BRAF wild-type MVHPs (n=58), demonstrated a strong correlation between CLDN1 expression and the BRAF V600E mutation in both SSA/P and MVHP samples when compared to wild-type polyps (p<0.0001). CONCLUSION: This study demonstrates an up regulation of CLDN1 protein in serrated colorectal polyps including MVHP harbouring the BRAF V600E mutation. Our results demonstrated an apparent heterogeneity on the molecular level within the MVHP group and suggest that MVHP with somatic BRAF V600E mutation and up-regulated expression of CLDN1 are closely related to SSA/P and may in fact represent a continuous spectrum of the same neoplastic process within the serrated pathway of colorectal carcinogenesis.

Epistemology of the origin of cancer: a new paradigm

Background

Carcinogenesis is widely thought to originate from somatic mutations and an inhibition of growth suppressors, followed by cell proliferation, tissue invasion, and risk of metastasis. Fewer than 10% of all cancers are hereditary; the ratio in gastric (1%), colorectal (3-5%) and breast (8%) cancers is even less. Cancers caused by infection are thought to constitute some 15% of the non-hereditary cancers. Those remaining, 70 to 80%, are called “sporadic,” because they are essentially of unknown etiology. We propose a new paradigm for the origin of the majority of cancers.

Presentation of hypothesis

Our paradigm postulates that cancer originates following a sequence of events that include (1) a pathogenic stimulus (biological or chemical) followed by (2) chronic inflammation, from which develops (3) fibrosis with associated changes in the cellular microenvironment. From these changes a (4) pre-cancerous niche develops, which triggers the deployment of (5) a chronic stress escape strategy, and when this fails to resolve, (6) a transition of a normal cell to a cancer cell occurs. If we are correct, this paradigm would suggest that the majority of the findings in cancer genetics so far reported are either late events or are epiphenomena that occur after the appearance of the pre-cancerous niche.

Testing the hypothesis

If, based on experimental and clinical findings presented here, this hypothesis is plausible, then the majority of findings in the genetics of cancer so far reported in the literature are late events or epiphenomena that could have occurred after the development of a PCN. Our model would make clear the need to establish preventive measures long before a cancer becomes clinically apparent. Future research should focus on the intermediate steps of our proposed sequence of events, which will enhance our understanding of the nature of carcinogenesis. Findings on inflammation and fibrosis would be given their warranted importance, with research in anticancer therapies focusing on suppressing the PCN state with very early intervention to detect and quantify any subclinical inflammatory change and to treat all levels of chronic inflammation and prevent fibrotic changes, and so avoid the transition from a normal cell to a cancer cell.

Implication of the hypothesis

The paradigm proposed here, if proven, spells out a sequence of steps, one or more of which could be interdicted or modulated early in carcinogenesis to prevent or, at a minimum, slow down the progression of many cancers.

TMPRSS4 correlates with colorectal cancer pathological stage and regulates cell proliferation and self-renewal ability

Transmembrane protease/serine 4 (TMPRSS4) is a member of the type II transmembrane serine protease (TTSP) family and it was found highly expressed in several cancers. This study aims to evaluate the expression of TMPRSS4 in colorectal cancer (CRC) and investigate its role in proliferation and self-renewal of colon cancer cells. qRT-PCR and immunohistochemistry were used to detect the mRNA and protein expression level of TMRPSS4 in CRC samples respectively. Loss of function assay was conducted with RNAi technique. Cell proliferation was done with WST-8 assay; cell apoptosis and cell cycle analysis were performed with flow cytometry; invasion and migration were done with transwell assay. Plate and soft agarose clonogenic assays were used to detect clone-formation ability. CD44 and CD133 expressions were analyzed by flow cytometry and western blot. We found that TMPRSS4 was highly expressed in CRC tissues both at mRNA and protein level and correlated with pathological stage. Knockdown of TMPRSS4 in highly expressed colon cancer cell line HCT116 resulted in inhibition of cell proliferation, induction of cell apoptosis and suppression of invasion and migration; moreover, knockdown of TMPRSS4 suppressed the in vitro clone-formation ability of HCT116 and reduced the expressions of CD44 and CD133. The findings in this research showed that TMPRSS4 was associated with CRC stage and regulated the proliferation and self-renewal ability of colon cancer cells; TMRPSS4 was involved in the development and progression of CRC.

Claudin-3 overexpression increases the malignant potential of colorectal cancer cells: roles of ERK1/2 and PI3K-Akt as modulators of EGFR signaling

The altered expressions of claudin proteins have been reported during the tumorigenesis of colorectal cancer. However, the molecular mechanisms that regulate these events in this cancer type are poorly understood. Here, we report that epidermal growth factor (EGF) increases the expression of claudin-3 in human colorectal adenocarcinoma HT-29 cells. This increase was related to increased cell migration and the formation of anchorage-dependent and anchorage-independent colonies. We further showed that the ERK1/2 and PI3K-Akt pathways were involved in the regulation of these effects because specific pharmacological inhibition blocked these events. Genetic manipulation of claudin-1 and claudin-3 in HT-29 cells showed that the overexpression of claudin-1 resulted in decreased cell migration; however, migration was not altered in cells that overexpressed claudin-3. Furthermore, the overexpression of claudin-3, but not that of claudin-1, increased the tight junction-related paracellular flux of macromolecules. Additionally, an increased formation of anchorage-dependent and anchorage-independent colonies were observed in cells that overexpressed claudin-3, while no such changes were observed when claudin-1 was overexpressed. Finally, claudin-3 silencing alone despite induce increase proliferation, and the formation of anchoragedependent and -independent colonies, it was able to prevent the EGF-induced increased malignant potential. In conclusion, our results show a novel role for claudin-3 overexpression in promoting the malignant potential of colorectal cancer cells, which is potentially regulated by the EGF-activated ERK1/2 and PI3K-Akt pathways.

Vitamin D3 insufficiency and colorectal cancer

Traditionally the main recognized function of vitamin D has been calcium and phosphate homeostasis. Nevertheless, recent evidences have highlighted the importance of vitamin D3 as a protective agent against various cancers. The association between CRC and vitamin D3 was first suggested in ecologic studies, but further was confirmed by observational studies in humans and experimental studies in both animal models and cellular lines. The protective role of vitamin D3 against cancer has been attributed to its influence of on cell proliferation, differentiation, apoptosis, DNA repair mechanisms, inflammation and immune function. In its active (calcitriol) form (1,25-dihydroxyvitamin D3[1α,25-(OH)2D3]) vitamin D3 and the nuclear vitamin D receptor (VDR) regulate hundreds of genes including those coding for proteins involved in cell differentiation and cell proliferation. The current review addresses some of the key mechanisms that influence the biological actions of vitamin D and its metabolites. The insights derived from these mechanisms may aid in designing new uses for this hormone and its non-hypercalcemic derivatives in the treatment and/or prevention of CRC.

Claudins and the modulation of tight junction permeability

Claudins are tight junction membrane proteins that are expressed in epithelia and endothelia and form paracellular barriers and pores that determine tight junction permeability. This review summarizes our current knowledge of this large protein family and discusses recent advances in our understanding of their structure and physiological functions.

Snail1 expression in colorectal cancer and its correlation with clinical and pathological parameters

Background

Snail1 is a transcription regulator of E-cadherin. The loss of E-cadherin seems to be a crucial step in the process of Epithelial-mesenchymal transition (EMT). EMT initiates invasion and proliferation in many tumours. Overexpression of Snail1 is known to be associated with poor outcome in several solid tumours. The aim of this study was to analyse its expression profile and prognostic significance in colorectal cancer.

Methods

Tissue microarrays (TMA) containing paraffin-embedded primary colorectal cancer (CRC) tissue samples from 251 patients were used in this study. The expression of Snail1 and E-cadherin was assessed by immunohistochemistry in different tumour compartments, corresponding lymph node metastases and normal colonic mucosa. Intensity of staining was classified according to the Remmele score (standardized scoring system) as well as the semiquantitative score established by Blechschmidt et al.

Results

Snail1 expression was observed in 76% of the CRC. Loss of E-cadherin was noted in 87% of the CRC. Snail1 positive tumours were significantly correlated with Snail1 positive lymph node metastases (p=0.03). There was no significant correlation between loss of E-cadherin and Snail1 expression, or between N-stage or grading and Snail1 expression. Kaplan-Meier survival analysis identified no prognostic impact of Snail1 expression on overall survival.

Conclusion

Snail1 expression was detectable in most of the CRC but showed no significant association with E-cadherin loss, clinical pathological characteristics or overall survival. The observed loss of E-cadherin could be explained by effects of other important EMT pathways, such as the Wnt-signalling cascade.

EMT-activating transcription factors in cancer: beyond EMT and tumor invasiveness

Cancer is a complex multistep process involving genetic and epigenetic changes that eventually result in the activation of oncogenic pathways and/or inactivation of tumor suppressor signals. During cancer progression, cancer cells acquire a number of hallmarks that promote tumor growth and invasion. A crucial mechanism by which carcinoma cells enhance their invasive capacity is the dissolution of intercellular adhesions and the acquisition of a more motile mesenchymal phenotype as part of an epithelial-to-mesenchymal transition (EMT). Although many transcription factors can trigger it, the full molecular reprogramming occurring during an EMT is mainly orchestrated by three major groups of transcription factors: the ZEB, Snail and Twist families. Upregulated expression of these EMT-activating transcription factors (EMT-ATFs) promotes tumor invasiveness in cell lines and xenograft mice models and has been associated with poor clinical prognosis in human cancers. Evidence accumulated in the last few years indicates that EMT-ATFs also regulate an expanding set of cancer cell capabilities beyond tumor invasion. Thus, EMT-ATFs have been shown to cooperate in oncogenic transformation, regulate cancer cell stemness, override safeguard programs against cancer like apoptosis and senescence, determine resistance to chemotherapy and promote tumor angiogenesis. This article reviews the expanding portfolio of functions played by EMT-ATFs in cancer progression.