Overall expression of beta-catenin outperforms its nuclear accumulation in predicting outcomes of colorectal cancers

KIS, a target of SOX4, regulates the ID1-mediated enhancement of β-catenin to facilitate lung adenocarcinoma cell proliferation and metastasis

PURPOSE

Kinase interacting with stathmin (KIS) is a serine/threonine kinase involved in RNA processing and protein phosphorylation. Increasing evidence has suggested its involvement in cancer progression. The aim of this study was to investigate the role of KIS in the development of lung adenocarcinoma (LUAD). Dual luciferase assay was used to explore the relationship between KIS and SOX4, and its effect on ID1/β-catenin pathway.

METHODS

Real-time qPCR and western blot were used to assess the levels of KIS and other factors. Cell proliferation, migration, and invasion were monitored, and xenograft animal model were established to investigate the biological functions of KIS in vitro and in vivo.

RESULTS

In the present study, KIS was found to be highly expressed in LUAD tissues and cell lines. KIS accelerated the proliferative, migratory and invasive abilities of LUAD cells in vitro, and promoted the growth of LUAD in a mouse tumor xenograft model in vivo. Mechanistically, KIS activated the β-catenin signaling pathway by modulating the inhibitor of DNA binding 1 (ID1) and was transcriptionally regulated by SOX4 in LUAD cells.

CONCLUSION

KIS, a target of SOX4, regulates the ID1-mediated enhancement of β-catenin to facilitate LUAD cell invasion and metastasis.

Exploring the pathogenesis of colorectal carcinoma complicated with hepatocellular carcinoma via microarray data analysis

Background: Despite the increasing number of research endeavors dedicated to investigating the relationship between colorectal carcinoma (CRC) and hepatocellular carcinoma (HCC), the underlying pathogenic mechanism remains largely elusive. The aim of this study is to shed light on the molecular mechanism involved in the development of this comorbidity. Methods: The gene expression profiles of CRC (GSE90627) and HCC (GSE45267) were downloaded from the Gene Expression Omnibus (GEO) database. After identifying the common differentially expressed genes (DEGs) of psoriasis and atherosclerosis, three kinds of analyses were performed, namely, functional annotation, protein-protein interaction (PPI) network and module construction, and hub gene identification, survival analysis and co-expression analysis. Results: A total of 150 common downregulated differentially expressed genes and 148 upregulated differentially expressed genes were selected for subsequent analyses. The significance of chemokines and cytokines in the pathogenesis of these two ailments is underscored by functional analysis. Seven gene modules that were closely connected were identified. Moreover, the lipopolysaccharide-mediated signaling pathway is intricately linked to the development of both diseases. Finally, 10 important hub genes were identified using cytoHubba, including CDK1, KIF11, CDC20, CCNA2, TOP2A, CCNB1, NUSAP1, BUB1B, ASPM, and MAD2L1. Conclusion: Our study reveals the common pathogenesis of colorectal carcinoma and hepatocellular carcinoma. These common pathways and hub genes may provide new ideas for further mechanism research.

Inhibitory effect of selected Indian honey on colon cancer cell growth by inducing apoptosis and targeting the β-catenin/Wnt pathway

Colon cancer is the most prevalent cause of death from cancer across the globe. Although chemotherapy drugs are predominantly used, their toxicity always remains a cause of concern. As an alternative to synthetic drugs, natural compounds or nutraceuticals are comparatively less toxic. Honey is widely used across different cultures as an alternative form of medicine. It represents a prominent source of plant-phenolic compounds and there is demonstrable evidence of its anti-oxidant and anti-microbial activities. The aim of the present work was to investigate the anti-proliferative effect of some Indian honeys and analyze their mechanism of action in colon cancer. In order to establish the composition-activity relationship, we evaluated the bioactive components present in selected honey samples by GC-MS and HPLC analysis. Indian honey samples showed a significant inhibitory impact on cell growth by restricting cell proliferation, causing apoptosis, and restricting the cell cycle in the G₂/M phase specifically for colon cancer cells. The apoptotic activities, as imparted by the honey samples, were established by Annexin V/PI staining, real-time PCR, and immunoblot analyses. The treated cells showed increased expressions of p53 and caspases 3, 8, and 9, thus indicating the involvement of both extrinsic and intrinsic apoptotic pathways. The honey samples were also found to inhibit the β-catenin/Wnt pathway. In the next phase of the study, the efficacy of these honey samples was evaluated in colon carcinoma induced SD-rats. Overall, these findings demonstrated that selected Indian honeys could be established as effective nutraceuticals for the prevention as well as cure of colon cancer.

Retinoic Acid-Induced 2 (RAI2) Is a Novel Antagonist of Wnt/β-Catenin Signaling Pathway and Potential Biomarker of Chemosensitivity in Colorectal Cancer

Objective

Aberrant activation of Wnt/β-catenin signaling contributes to the maintenance of cancer stem cells and chemoresistance in colorectal cancer (CRC). Retinoic acid-induced 2 (RAI2) was proved to be a tumor suppressor in CRC in our previous report. In this study, the role of RAI2 in Wnt/β-catenin signaling was further investigated.

Methods

As a transcriptional co-regulator, C-terminal Binding Protein 2 (CtBP2) was reported to be involved in Wnt signaling in multiple and complex ways. The correlation of RAI2 and CtBP2 in CRC was analyzed by TCGA dataset, and the interaction between RAI2 and CtBP2 was explored by co-immunoprecipitation (Co-IP) in CRC cells. The effect of RAI2 on the activity of Wnt signaling and the location of β-catenin was detected by Dual-Luciferase reporter assay and Immunofluorescence respectively. Western blotting analysis was performed to detect the expression of target genes involved in Wnt signaling. Sphere formation assay was employed to detect the effect of RAI2 on stem cell like properties. Cell viability assay was used to detect the chemosensitivity of cells before and after transfection of RAI2.

Results

The interaction between RAI2 and CtBP2 was confirmed by Co-IP in CRC cells. Besides, the negative correlation of RAI2 and CtBP2 in CRC was found by analyzing the TCGA dataset. Re-expression of RAI2 in human colon cancer cells (HCT116 and LoVo) suppressed the fluorescent activity of Wnt signaling, increased the phosphorylation and inhibited nuclear translocation of β-catenin, with down-regulation of target genes like c-Myc, CyclinD1, ASCL2, and LGR5. In contrast, the mutated RAI2, which can’t interact with CtBP2, has no above effects. We observed low expression of RAI2 in 33.89% (101/298) of CRC patients, which was significantly associated with reduced phosphorylation of β-catenin (r=0.8866, P<0.0001), poor 5-year relapse-free survival (RFS) (P = 0.0029) and overall survival (OS) (P = 0.0102). Restoration of RAI2 in HCT116 and LoVo cells inhibited stem cell-like properties of CRC cells and increased chemosensitivity of these cells to oxaliplatin and fluorouracil.

Conclusion

Low expression of RAI2 can serve as an independent poor prognostic marker. RAI2 inhibits Wnt signaling by interacting with or down-regulating CtBP2, resulting in repression of stem cell-like properties and increased chemosensitivity of CRC cells.

TNKS inhibitors potentiate proliferative inhibition of BET inhibitors via reducing β-Catenin in colorectal cancer cells

Colorectal cancer (CRC) is an aggressive malignancy with limited options for treatment. Targeting the bromodomain and extra terminal domain (BET) proteins by using BET inhibitors (BETis) could effectively interrupt the interaction with acetylated histones, inhibit genes transcription and have shown a certain effect on CRC inhibition. To improve the efficacy, the inhibitors of Tankyrases, which cause accumulation of AXIN through dePARsylation, in turn facilitate the degradation of β-Catenin and suppress the growth of adenomatous polyposis coli (APC)-mutated CRCs, were tested together with BETi as a combination treatment. We examined the effects of BETi and Tankyrases inhibitor (TNKSi) together on the proliferation, cell cycle and apoptosis of human CRCs cell lines with APC or CTNNB1 mutation, and elucidated the underlying molecular mechanisms affected by the double treatment. The result showed that the TNKSi could sensitize all tested CRC cell lines to BETi, and the synergistic effect was not only seen in cell proliferation inhibition, but also confirmed in decreased colony-forming ability and weaken EdU incorporation compared with monotherapy. Combined treatment resulted in enhanced G1 cell cycle arrest and increased apoptosis. In addition, we found β-Catenin was potentially inhibited by the combination and revealed that both BETi-induced transcriptional inhibition and TNKSi-mediated protein degradation all reduced the β-Catenin accumulation. In all, the synergistic effects suggest that combination of BETi and TNKSi could provide novel treatment opportunities for CRC, but both TNKSi and combination strategy need to be optimized.

Using Immune-Related Long Non-coding Ribonucleic Acids to Develop a Novel Prognosis Signature and Predict the Immune Landscape of Colon Cancer

Purpose: This study aimed to construct a novel signature to predict the survival of patients with colon cancer and the associated immune landscape, based on immune-related long noncoding ribonucleic acids (irlncRNAs).

Methods: Expression profiles of irlncRNAs in 457 patients with colon cancer were retrieved from the TCGA database (https://portal.gdc.cancer.gov). Differentially expressed (DE) irlncRNAs were identified and irlncRNA pairs were recognized using Lasso regression and Cox regression analyses. Akaike information criterion (AIC) values of receiver operating characteristic (ROC) curve were calculated to identify the ideal cut-off point for dividing patients into two groups and constructing the prognosis signature. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to validate the expression of LINC02195 and SCARNA9 in colon cancer.

Results: We identified 22 irlncRNA pairs and patients were divided into high-risk and low-risk groups based on the calculated risk score using these 22 irlncRNA pairs. The irlncRNA pairs were significantly related to patient survival. Low-risk patients had a significantly longer survival time than high-risk patients (p < 0.001). The area under the curve of the signature to predict 5-year survival was 0.951. The risk score correlated with tumor stage, infiltration depth, lymph node metastasis, and distant metastasis. The risk score remained significant after univariate and multivariate Cox regression analyses. A nomogram model to predict patient survival was developed based on the results of Cox regression analysis. Immune cell infiltration status, expression of some immune checkpoint genes, and sensitivity to chemotherapeutics were also related to the risk score. The results of qRT-PCR revealed that LINC02195 and SCARNA9 were significantly upregulated in colon cancer tissues.

Conclusion: The constructed prognosis signature showed remarkable efficiency in predicting patient survival, immune cell infiltration status, expression of immune checkpoint genes, and sensitivity to chemotherapeutics.

Involvement of integrin-activating peptides derived from tenascin-C in colon cancer progression

Tenascin-C (TNC) is an adhesion modulatory protein present in the extracellular matrix that is highly expressed in several malignancies, including colon cancer. Although TNC is considered a negative prognostic factor for cancer patients, the substantial role of the TNC molecule in colorectal carcinogenesis and its malignant progression is poorly understood. We previously found that TNC has a cryptic functional site and that a TNC peptide containing this site, termed TNIIIA2, can potently and persistently activate beta1-integrins. In contrast, the peptide FNIII14, which contains a cryptic bioactive site within the fibronectin molecule, can inactivate beta1-integrins. This review presents the role of TNC in the development of colitis-associated colorectal cancer and in the malignant progression of colon cancer, particularly the major involvement of its cryptic functional site TNIIIA2. We propose new possible prophylactic and therapeutic strategies based on inhibition of the TNIIIA2-induced beta1-integrin activation by peptide FNIII14.

Myofibroblasts: Function, Formation, and Scope of Molecular Therapies for Skin Fibrosis

Myofibroblasts are contractile, α-smooth muscle actin-positive cells with multiple roles in pathophysiological processes. Myofibroblasts mediate wound contractions, but their persistent presence in tissues is central to driving fibrosis, making them attractive cell targets for the development of therapeutic treatments. However, due to shared cellular markers with several other phenotypes, the specific targeting of myofibroblasts has long presented a scientific and clinical challenge. In recent years, myofibroblasts have drawn much attention among scientific research communities from multiple disciplines and specialisations. As further research uncovers the characterisations of myofibroblast formation, function, and regulation, the realisation of novel interventional routes for myofibroblasts within pathologies has emerged. The research community is approaching the means to finally target these cells, to prevent fibrosis, accelerate scarless wound healing, and attenuate associated disease-processes in clinical settings. This comprehensive review article describes the myofibroblast cell phenotype, their origins, and their diverse physiological and pathological functionality. Special attention has been given to mechanisms and molecular pathways governing myofibroblast differentiation, and updates in molecular interventions.

Exosomal miR-183-5p Shuttled by M2 Polarized Tumor-Associated Macrophage Promotes the Development of Colon Cancer via Targeting THEM4 Mediated PI3K/AKT and NF-κB Pathways

Background

Abnormal accumulation of macrophages in the colon cancer (CC) contribute to its progression. miR-183-5p has been confirmed as an oncogene in CC and this article explores the effect and mechanism of exosomal miR-183-5p enriched by M2-polarized tumor-associated macrophages (TAM) on CC cells.

Methods

The human macrophage THP1 was induced to M2 polarization through IL-4 and IL-13 treatment. Exosomes in THP1 were isolated through ultracentrifugation, and the miR-183-5p expression in macrophages and exosomes was verified by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The miR-183-5p inhibitors and mimics were applied to down-regulate and upregulate miR-183-5p in macrophages, respectively. Meanwhile, CC cell lines LoVo and SW480 were treated with the macrophage conditioned medium and exosomes, respectively. CC cells’ proliferation, invasion, and apoptosis were tested by the cell counting kit-8 (CCK-8) assay, colony formation assay, flow cytometry (FCM), Transwell assay, and xenograft assay, respectively. The profiles of thioesterase superfamily member 4 (THEM4), Akt, and NF-κB were compared by Western blotting (WB).

Results

The miR-183-5p level in M2-TAM and M2-TAM-derived exosomes was significantly increased. Meanwhile, M2-TAM and M2-TAM-derived exosomes significantly facilitated CC cell proliferation and invasion and dampened apoptosis. Overexpression of miR-183-5p in M2-TAM aggravated M2-TAM-mediated promotive effects on CC cells, with down-regulating miR-183-5p reversed M2-TAM-mediated tumor-promotive effects. Mechanically, miR-183-5p targeted THEM4 and inhibited its mRNA and protein expression. Overexpressing THEM4 abated miR-183-5p-mediated carcinogenic effects and inactivates Akt and NF-κB pathways in CC cells. Overall, this article elaborated that exosomal miR-183-5p shuttled by M2-TAM mediated Akt/NF-κB pathway to accelerate CC progression through targeting THEM4.

Aberrant KIF23 expression is associated with adverse clinical outcome and promotes cellular malignant behavior through the Wnt/β-catenin signaling pathway in Colorectal Cancer

Purpose: The aim of the present study was to reveal the clinicopathological significance and prognostic role of kinesin family member 23 (KIF23) in colorectal cancer (CRC) and characterize its biological function and the underlying mechanisms.

Methods: Bioinformatics analysis, immunohistochemistry, Western blot and qRT-PCR were utilized to investigate the expression of KIF23 in CRC tissues. The CCK-8 assay, wound healing assay and Matrigel assay were used to detect cell proliferation, migration and invasion in vitro. Western blot, immunofluorescence staining and cell function experiment were performed to explore the underlying mechanism.

Results: The overexpression of KIF23 was associated with T stage, N stage, M stage and TNM stage, and CRC patients with high KIF23 expression had a worse prognosis. KIF23 knockdown inhibits CRC cells proliferation, migration and invasion in vitro. The mechanism study determined that KIF23 activates the Wnt/β-catenin signaling pathway by promoting the nuclear translocation of β-catenin to regulate the malignant behavior of CRC cells.

Conclusion: These results suggest that KIF23 may act as a putative oncogene and a potential therapeutic target in CRC.

Molecular docking analysis of beta-catenin with compounds derived from Lycopersicon esculentum

Beta-catenin is linked with colorectal cancer (CRC). Therefore, it is of interest to design and develop novel compounds to combat CRC. Hence, we document compounds (chlorogenic acid, gallic acid, protocatechuic acid, quercetin and vanillic acid) from Lycopersicon esculentum with optimal binding features for further consideration.

Chlorquinaldol targets the β-catenin and T-cell factor 4 complex and exerts anti-colorectal cancer activity

Aberrant activation of Wnt signaling plays a critical role in the initiation and progression of colorectal cancer (CRC). Chlorquinaldol (CQD) is a topical antimicrobial agent used to treat skin infections. Little is known about the anticancer activity of CQD and its underlying mechanisms. In this study, CQD was demonstrated to inhibit Wnt/β-catenin signaling through targeting the downstream part of this pathway. The results showed that CQD could inhibit the acetylation of β-catenin and disrupt the interaction of β-catenin with T-cell factor 4 (TCF4), leading to reduced binding of β-catenin to the promoters of Wnt target genes and downregulation of the expression of these target genes. Moreover, treatment with CQD suppressed the proliferation, migration, invasion and stemness of CRC cells. In APC^min/+ mice and CRC cell xenografts, administration of CQD suppressed tumor growth and the expression of Wnt target genes c-Myc and Leucine-rich G protein-coupled receptor-5 (LGR5). These results strongly suggest that CQD may be a promising therapeutic agent in the treatment of CRC.

MALAT1 overexpression promotes the growth of colon cancer by repressing β-catenin degradation

Colon cancer is one of the most common types of cancer and more than 80% of colon cancer cases are associated with Wnt-β-catenin signaling activation. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a multi-functional long non-coding RNA that is overexpressed in many types of cancers, including colon cancer. In this study, MALAT1 and β-catenin were found to be overexpressed in tumor samples from 62 patients with colon cancer. A positive correlation was identified between MALAT1 levels and β-catenin protein levels in tumors. MALAT1 was found to upregulate β-catenin protein levels in HCT116 and LOVO cells without changing the mRNA expression levels. β-catenin degradation was confirmed to be upregulated in MALAT1-knockdown cells and inhibited in cells overexpressing MALAT1 overexpressing. MALAT1 was then identified as a negative regulator of GSK-3β; it did so via promotion of H3K27 trimethylation of the promoter region. In conclusion, MALAT1 is an oncogene in colon cancer, which inhibits β-catenin degradation by upregulating H3K27 trimethylation and repressing GSK-3β expression.

Hypoxia-Induced miR-675-5p Supports β-Catenin Nuclear Localization by Regulating GSK3-β Activity in Colorectal Cancer Cell Lines

The reduction of oxygen partial pressure in growing tumors triggers numerous survival strategies driven by the transcription factor complex HIF1 (Hypoxia Inducible Factor-1). Recent evidence revealed that HIF1 promotes rapid and effective phenotypic changes through the induction of non-coding RNAs, whose contribution has not yet been fully described. Here we investigated the role of the hypoxia-induced, long non-coding RNA H19 (lncH19) and its intragenic miRNA (miR-675-5p) into HIF1-Wnt crosstalk. During hypoxic stimulation, colorectal cancer cell lines up-regulated the levels of both the lncH19 and its intragenic miR-675-5p. Loss of expression experiments revealed that miR-675-5p inhibition, in hypoxic cells, hampered β-catenin nuclear localization and its transcriptional activity, while lncH19 silencing did not induce the same effects. Interestingly, our data revealed that miRNA inhibition in hypoxic cells restored the activity of Glycogen Synthase Kinase 3β (GSK-3β) reducing the amount of P-Ser9 kinase, thus unveiling a role of the miR-675-5p in controlling GSK-3β activity. Bioinformatics analyses highlighted the serine/threonine-protein phosphatases PPP2CA, responsible for GSK-3β activation, among the miR-675-5p targets, thus indicating the molecular mediator through which miR-675-5p may control β-catenin nuclear localization. In conclusion, here we demonstrated that the inhibition of the hypoxia-induced non-coding RNA miR-675-5p hampered the nuclear localization of β-catenin by regulating GSK-3β activity, thus proposing the miR-675-5p as a new therapeutic target for the treatment of colorectal cancer.

Columbamine suppresses the proliferation and malignization of colon cancer cells via abolishing Wnt/β-catenin signaling pathway

BACKGROUND

Colon cancer is one of the most common malignancies worldwide. Because of the side effects and defects in tolerance of chemotherapy, it is necessary to discover new drugs for colon cancer treatment. Columbamine has been identified as an effective anti-osteosarcoma compound with only minor side effects. In this study, we analyzed the anticancer effect of columbamine on colon cancer.

METHODS

Human colon cancer cell lines were treatment with columbamine. MTT assay, colony formation assay, apoptosis detection and tumorigenicity assay were performed to detect the protective effect of columbamine on colon cancer development. Western blot assay and luciferase reporter assay were conducted to investigate the potential mechanism of the columbamine treatment.

RESULTS

Columbamine significantly inhibited the proliferation, migration, invasion process of colon cancer cells, and dramatically promoted the apoptosis rate of colon cancer cells to further suppress the development of colon cancer to tumor. Both the signaling transducing and key factors expression of Wnt/β-catenin signaling pathway were obviously repressed by columbamine treatment in a dose-dependent manner.

CONCLUSION

The present study indicated that columbamine exerts its anti-tumor effect in colon cancer cells through abolishing Wnt/β-catenin signaling pathway. Columbamine may be a new therapy compound for colon cancer.

Salinomycin exerts anti-colorectal cancer activity by targeting the β-catenin/T-cell factor complex

BACKGROUND AND PURPOSE

Salinomycin is a well-known inhibitor of human cancer stem cells (CSCs). However, the molecular mechanism(s) by which salinomycin targets colorectal CSCs is poorly understood. Here, we have investigated underlying antitumour mechanisms of salinomycin in colorectal cancer cells and three tumour models.

EXPERIMENTAL APPROACH

The inhibitory effect of salinomycin on the Wnt/β-catenin pathway was analysed with the SuperTopFlash reporter system. The mRNA expression of Wnt target genes was evaluated with real-time PCR. Effects of salinomycin on β-catenin/TCF4E interaction were examined using co-immunoprecipitation and an in vitro GST pull-down assay. Cell proliferation was determined by BrdU incorporation and soft agar colony formation assay. The stemness of the cells was assessed by sphere formation assay. Antitumour effects of salinomycin on colorectal cancers was evaluated with colorectal CSC xenografts, APCmin/+ transgenic mice, and patient-derived colorectal tumour xenografts.

KEY RESULTS

Salinomycin blocked β-catenin/TCF4E complex formation in colorectal cancer cells and in an in vitro GST pull-down assay, thus decreasing expression of Wnt target genes. Salinomycin also suppressed the transcriptional activity mediated by β-catenin/LEF1 or β-catenin/TCF4E complex and exhibited an inhibitory effect on the sphere formation, proliferation, and anchorage-independent growth of colorectal cancer cells. In colorectal tumour xenografts and APCmin/+ transgenic mice, administration of salinomycin significantly reduced tumour growth and the expression of CSC-related Wnt target genes including LGR5.

CONCLUSIONS AND IMPLICATIONS

Our study suggested that salinomycin could suppress the growth of colorectal cancer by disrupting the β-catenin/TCF complex and thus may be a promising agent for colorectal cancer treatment.

Emodin Inhibits Colon Cancer Cell Invasion and Migration by Suppressing Epithelial-Mesenchymal Transition via the Wnt/β-Catenin Pathway

Colon cancer (CC) is the third most common cancer worldwide. Emodin is an anthraquinone-active substance that has the ability to affect tumor progression. Our study aims to explore the effects and the relevant mechanism of emodin on the invasion and migration of CC in vitro and in vivo. In our study, we found that emodin inhibited the invasion and migration abilities of RKO cells and decreased the expression of matrix metalloproteinase-7 (MMP-7), MMP-9, and vascular endothelial growth factor (VEGF) in a dose-dependent manner. Further research suggested that emodin inhibited EMT by increasing the mRNA level of E-cadherin and decreasing the expression of N-cadherin, Snail, and β-catenin. Emodin also significantly inhibited the activation of the Wnt/β-catenin signaling pathway by downregulating the expression of related downstream target genes, including TCF4, cyclin D1, and c-Myc. A Wnt/β-catenin signaling pathway agonist abolished the effect of emodin on EMT and cell mobility, suggesting that emodin exerted its regulating role through the Wnt/β-catenin pathway. The CC xenograft model was established to study the antitumor efficiency of emodin in vivo. The in vivo study further demonstrated that emodin (40 mg/kg) suppressed tumor growth by inhibiting EMT via the Wnt/β-catenin signaling pathway in vivo. Taken together, we suggest that emodin inhibits the invasion and migration of CC cells in vitro and in vivo by blocking EMT, which is related with the inhibition of the Wnt/β-catenin signaling pathway.

Molecular dynamic simulation of mutated β-catenin in solid pseudopapillary neoplasia of the pancreas

Solid pseudopapillary neoplasia of the pancreas (SPN) is a rare pancreatic neoplasm that frequently harbors mutations in catenin β1 (CTNNB1, encoding β-catenin) as a part of its molecular pathogenesis. Mutations to CTNNB1 reported in SPN usually occur at the serine/threonine phosphorylation sites, including codons 33, 37 and 41, and the flanking residues of codon 33. On analysis of 3 cases of SPN, mutations to CTNNB1 were detected in codon 32 (D32A and D32Y). As this residue, aspartic acid, is not a direct phosphorylation site of the protein, molecular modeling tools were used to predict the influence of these mutations on the protein structure of β-catenin. A total of three MD simulations (wild-type, D32A, and D32Y) were performed to visualize the conformations of β-catenin under in vivo, aqueous-phase conditions at 37°C. In the wild-type protein, the secondary structure of residues P16-H28 remained helical; we therefore hypothesized that the helical structure of this protein fragment (residues M11-G50) was necessary for phosphorylation of S33 phosphorylation. The loss of the secondary structure in P16-H28 was observed in D32A, losing its helical structure and becoming a turn; however, in the D32Y mutant, the helical structure remained. The present demonstrated that structural changes in the mutated β-catenin protein at D32 could potentially explain the mechanism behind its defective phosphorylation in the pathogenesis of SPN.

A scoring system based on artificial neural network for predicting 10-year survival in stage II A colon cancer patients after radical surgery

Nearly 20% patients with stage II A colon cancer will develop recurrent disease post-operatively. The present study aims to develop a scoring system based on Artificial Neural Network (ANN) model for predicting 10-year survival outcome. The clinical and molecular data of 117 stage II A colon cancer patients from Sun Yat-sen University Cancer Center were used for training set and test set; poor pathological grading (score 49), reduced expression of TGFBR2 (score 33), over-expression of TGF-β (score 45), MAPK (score 32), pin1 (score 100), β-catenin in tumor tissue (score 50) and reduced expression of TGF-β in normal mucosa (score 22) were selected as the prognostic risk predictors. According to the developed scoring system, the patients were divided into 3 subgroups, which were supposed with higher, moderate and lower risk levels. As a result, for the 3 subgroups, the 10-year overall survival (OS) rates were 16.7%, 62.9% and 100% (P < 0.001); and the 10-year disease free survival (DFS) rates were 16.7%, 61.8% and 98.8% (P < 0.001) respectively. It showed that this scoring system for stage II A colon cancer could help to predict long-term survival and screen out high-risk individuals for more vigorous treatment.

Rapidly cycling Lgr5+ stem cells are exquisitely sensitive to extrinsic dietary factors that modulate colon cancer risk

The majority of colon tumors are driven by aberrant Wnt signaling in intestinal stem cells, which mediates an efficient route toward initiating intestinal cancer. Natural lipophilic polyphenols and long-chain polyunsaturated fatty acids (PUFAs) generally suppress Wnt- and NF-κB- (nuclear factor-κ light-chain enhancer of activated B-cell) related pathways. However, the effects of these extrinsic agents on colonic leucine-rich repeat-containing G-protein-coupled receptor 5-positive (Lgr5⁺) stem cells, the cells of origin of colon cancer, have not been documented to date. Therefore, we examined the effect of n-3 PUFA and polyphenol (curcumin) combination on Lgr5⁺ stem cells during tumor initiation and progression in the colon compared with an n-6 PUFA-enriched control diet. Lgr5-EGFP-IRES-^creERT2 knock-in mice were fed diets containing n-6 PUFA (control), n-3 PUFA, n-6 PUFA+curcumin or n-3 PUFA+curcumin for 3 weeks, followed by 6 azoxymethane (AOM) injections, and terminated 17 weeks after the last injection. To further elucidate the effects of the dietary bioactives at the tumor initiation stage, Lgr5⁺ stem cells were also assessed at 12 and 24 h post AOM injection. Only n-3 PUFA+curcumin feeding reduced nuclear β-catenin in aberrant crypt foci (by threefold) compared with control at the progression time point. n-3 PUFA+curcumin synergistically increased targeted apoptosis in DNA-damaged Lgr5⁺ stem cells by 4.5-fold compared with control at 12 h and maximally reduced damaged Lgr5⁺ stem cells at 24 h, down to the level observed in saline-treated mice. Finally, RNAseq analysis indicated that p53 signaling in Lgr5⁺ stem cells from mice exposed to AOM was uniquely upregulated only following n-3 PUFA+curcumin cotreatment. These novel findings demonstrate that Lgr5⁺ stem cells are uniquely responsive to external dietary cues following the induction of DNA damage, providing a therapeutic strategy for eliminating damaged Lgr5⁺ stem cells to reduce colon cancer initiation.

[Impact of preoperative drug therapy on adhesion molecule expression in colorectal cancer liver metastases]

OBJECTIVE

To study E-cadherin and β-catenin expression in colorectal cancer (CRC) liver metastases in order to assess the impact of different drug therapy regimens on the adhesive properties of tumor cells.

MATERIAL AND METHODS

Intraoperative metastatic CRC samples from patients who had received preoperative cytotoxic chemotherapy or combined cytotoxic and targeted anti-VEGF (vascular endothelial growth factor) therapy were immunohistochemically examined using antibodies to E-cadherin and β-catenin. A comparison group consisted of patients who had not received drug therapy.

RESULTS

Combined therapy with cytotoxic and anti-VEGF agents was shown to result in a significant increase in the number of cases of normal membrane localization of E-cadherin as compared with control (p = 0.00043) and cytotoxic therapy-alone (p = 0.01) groups. A comparison of β-catenin levels in three patient groups revealed no significant differences, but addition of an anti-VEGF agent caused some decrease in the number of cases of abnormal nuclear localization of the protein as compared to both the control group and the cytotoxic therapy groups. The comparison of E-cadherin and β-catenin localization in tumor cells showed that a combination of normal E-cadherin membrane localization and β-catenin membrane-cytoplasmic expression prevailed in the combined therapy group compared to the control (p = 0.009) and cytotoxic therapy (p = 0.04) groups.

CONCLUSION

The addition of a targeted anti-VEGF agent to the drug therapy of metastatic CRC has a positive impact on the cadherin-catenin complex, leading to increased intercellular contacts and suppressed β-catenin functioning as a transcription factor that enhances tumor cell proliferation.

Kuppen P. Prognostic Significance of Nuclear β-Catenin Expression in Patients with Colorectal Cancer from Iran

Background:

Beta catenin plays a key role in cancer tumorigenesis. However, its prognostic significance in patients with colorectal cancer (CRC) remains controversial. It has been demonstrated that 90% of all tumors have a mutation in individual components of multiple oncogenes in Wnt/β-catenin pathway. Accumulation of nuclear β-catenin in cytoplasm leads to uncontrolled cell proliferation. Thus, nuclear β-catenin accumulation may be a valuable biomarker associated with invasion, metastasis and poor prognosis of CRC.

Objectives:

In this study the prognostic value of beta catenin expression in 165 Iranian CRC patients was evaluated.

Patients and Methods:

In this cross sectional retrospective study immunohistochemistry analyses of formalin-fixed paraffin-embedded (FFPE) tumor tissues were performed to characterize the expression of nuclear β-catenin in a series of 165 Iranian patients with colorectal carcinoma. Heat-induced antigen retrieval using the microwave method was applied for all staining procedures. Staining was scored independently by two observers, and a high level of concordance (90%) was achieved. Statistical analysis was done using the SPSS software for Windows, version 13.0.0 (SPSS Inc., Chicago, IL). Two-tailed P < 0.05 was considered statistically significant.

Results:

The patients consisted of 85 males and 80 females. Eighty-eight patients had primary tumor of the rectum and sigmoid, while 77 patients had primary tumor of the colon. The mean period of follow-up was 47.2 ± 10 months and the median period of follow-up was 38 months (range 6 - 58) for each patient. Of 165 tumors, 32 tumors (19.39 %) showed expression of β-catenin and 133 (80.6 %) were negative for β-catenin expression. Based on our findings the distribution of Microsatellite Instability (MSI) status differed between patients with nuclear β-catenin positive and negative tumors and this difference was significant (P = 0.001). Patients with nuclear β-catenin positive expression profile were found to be younger than patients with negative nuclear β-catenin expression (P = 0.010). Univariate and multivariate analysis showed that tumors with β-catenin expression had a poorer prognosis compared to tumors without β-catenin expression.

Conclusions:

According to our findings, the distribution of nuclear b-catenin expression is a poor prognostic marker in patients with colon cancer.

Expression of wingless-type mouse mammary tumor virus integration site family pathway effectors in lymphatic and hepatic metastases of patients with colorectal cancer: Associations with the primary tumor

The wingless-type mouse mammary tumor virus integration site family (Wnt) pathway plays a major role in the carcinogenesis of colorectal cancer (CRC). Its most important effector, the nuclear β-catenin, influences not only transcription but also the proliferation and dedifferentiation of the colonic mucosa. This induces an epithelial-mesenchymal transition which ultimately can lead to the development of cancer and the formation of metastases. However, little is known about the exact interaction and context-sensitive expression of Wnt-pathway effectors in the primary tumor and corresponding metastasis. Therefore, this study assessed the expression of the three most important effectors of the Wnt pathway, β-catenin, adenomatous polyposis coli (APC) and Wnt-1, in the primary tumor and corresponding metastasis of patients with CRC. Immunohistochemical staining of β-catenin, APC and Wnt-1 was performed in paraffin-embedded tissue samples of the primary tumor, and the corresponding hepatic and nodal metastasis samples from 24 patients with metastatic CRC. Isotype antibodies were used as negative controls. The results were visualized using the ABC-method. Analysis of the primary tumor comprised of a separate evaluation of the central tumor area as well as the invasion front. There was a significant overexpression of nuclear β-catenin at the tumor invasion front (P<0.001). Compared to normal colonic mucosa, expression of cytoplasmic β-catenin was significantly higher in the primary tumor (P<0.001) as well as all the corresponding hepatic and lymphatic metastases (hepatic metastases, P=0.001; nodal metastases, P=0.017). By contrast, APC expression was significantly lower in all analyzed tumor compartments compared with normal colonic mucosa (primary tumor, P=0.022; hepatic metastases, P=0.006; nodal metastases, P=0.012). Finally, Wnt-1 protein expression was significantly lower in liver metastases but not in the primary tumor or lymphatic metastases compared with normal colonic mucosa (P=0.003). The present study demonstrates that the major Wnt-effector proteins, β-catenin, APC and Wnt-1, are heterogeneously expressed in the primary tumor and corresponding hepatic as well as nodal metastases of patients with CRC. This context-sensitive diverse expression of Wnt-effector proteins may be important for future individualized targeted therapies.

Prognostic Significance of β-Catenin, E-Cadherin, and SOX9 in Colorectal Cancer: Results from a Large Population-Representative Series

Robust biomarkers that can precisely stratify patients according to treatment needs are in great demand. The literature is inconclusive for most reported prognostic markers for colorectal cancer (CRC). Hence, adequately reported studies in large representative series are necessary to determine their clinical potential. We investigated the prognostic value of three Wnt signaling-associated proteins, β-catenin, E-cadherin, and SOX9, in a population-representative single-hospital series of 1290 Norwegian CRC patients by performing immunohistochemical analyses of each marker using the tissue microarray technology. Loss of membranous or cytosolic β-catenin and loss of cytosolic E-cadherin protein expression were significantly associated with reduced 5-year survival in 903 patients who underwent major resection (722 evaluable tissue cores) independently of standard clinicopathological high-risk parameters. Pre-specified subgroup analyses demonstrated particular effect for stage IV patients for β-catenin membrane staining (P = 0.018; formal interaction test P = 0.025). Among those who underwent complete resection (714 patients, 568 evaluable), 5-year time-to-recurrence analyses were performed, and stage II patients with loss of cytosolic E-cadherin were identified as an independent high-risk subgroup (P = 0.020, formal interaction test was not significant). Nuclear β-catenin and SOX9 protein, regardless of intracellular location, were not associated with prognosis. In conclusion, the protein expression level of membranous or cytosolic β-catenin and E-cadherin predicts CRC patient subgroups with inferior prognosis.

The potential of targeting Wnt/β-catenin in colon cancer

The Wnt signaling pathway controls several cell processes, such as motility and proliferation during embryonic development. Wnt signaling is also involved in the maintenance of potency and the induction of differentiation in stem cells. Aberrant Wnt signaling is implicated in several cancer types. Particularly in colorectal cancer (CRC), the Wnt-β-catenin signaling cascade is at the center of the carcinogenesis, and mutations in this pathway can be found in almost all CRC patients. We discuss the potential of targeting Wnt-β-catenin signaling with a brief overview of the pathway and the most promising pathway inhibitors.

Expression of RUNX3 and β-catenin in the carcinogenesis of sporadic colorectal tubular adenoma

The aim of this study is to investigate the possible roles of runt-related transcription factor 3 (RUNX3) and β-catenin in the carcinogenesis of sporadic colorectal tubular adenomas. The expression of the RUNX3 and β-catenin proteins was evaluated by immunohistochemistry in 23 normal colorectal mucosa (NCM), 81 sporadic colorectal tubular adenomas with different dysplasias (SCTA-D) (mild n=33, moderate n=23, and severe n=25 dysplasia), and 48 sporadic colorectal tubular adenomas with cancerous changes (SCTA-Ca). RUNX3 methylation was assessed by methylation-specific polymerase chain reaction (MSP), combined with laser capture microdissection (LCM), in 17 NCM, 41 SCTA-D (mild n=15, moderate n=12, and severe n=14 dysplasia), and 17 SCTA-Ca tissues. Compared to NCM (82.6 %), RUNX3 in SCTA-D (54.3 %) and SCTA-Ca (27.1 %) was significantly downregulated (P<0.05). In NCM, SCTA-D, and SCTA-Ca, the incidence of positive expression for β-catenin was 13.0, 60.5, and 79.2 %, respectively. A statistically significant difference was observed (P<0.05). RUNX3 levels were markedly higher in adenoma with mild dysplasia (75.8 %) and moderate dysplasia (60.9 %) than in adenoma with severe dysplasia (20.0 %) (both with P<0.05). Likewise, the expression of β-catenin in severe dysplasia adenoma was 84.0 %, which was significantly higher than that in mild dysplasia adenoma (39.4 %). An inverse correlation was found between the protein expression of RUNX3 and β-catenin in SCTA-D and SCTA-Ca (P<0.05). MSP results showed that RUNX3 methylation in NCM, SCTA-D, and SCTA-Ca was 5.9, 17.1, and 41.2 %, respectively, with a statistically significant difference between NCM and SCTA-Ca (P<0.05). However, no significant difference of RUNX3 methylation was observed among different dysplasia groups. RUNX3 and β-catenin play important roles in the carcinogenesis of sporadic colorectal tubular adenomas. In addition, hypermethylation of RUNX3 can downregulate its expression.

Molecular therapy of colorectal cancer: progress and future directions

Colorectal cancer (CRC) remains one of the most common types of cancer and leading causes of cancer death worldwide. Although the introduction of cytotoxic drugs such as oxaliplatin, irinotecan and fluorouracil has improved the treatment of advanced CRC, the individual response to chemoradiotherapy varies tremendously from one patient to another. However, recent progress in CRC molecular therapies may provide new insight into the treatment of this disease. Currently, components of the EGFR, VEGF, Wnt and NF-kB pathways are the most important targets for CRC therapy. This review chronicles the development of molecular CRC therapies over the past few decades. We also provide an update on the current progress of research concerning the molecular pathways leading to CRC and discuss the possible implications for CRC therapy.

Clinical significance of long intergenic noncoding RNA-p21 in colorectal cancer

BACKGROUND

Long intergenic noncoding RNAs (lincRNAs) have been shown to be novel regulators for both transcription and posttranscriptional/translation. One of them, lincRNA-p21, was regulated by p53 and contributed to apoptosis in mouse embryonic fibroblasts. However, the impact of such regulation on colorectal cancer (CRC) remains to be determined.

METHODS

Total RNA was extracted from CRC cell lines and snap fresh frozen CRC samples from 2 CRC patient cohorts. The expression of lincRNA-p21 was quantified by quantitative real-time polymerase chain reaction analysis.

RESULTS

We discovered that the expression level of lincRNA-p21 was increased by elevated wild-type p53 induced by nutlin-3 in HCT-116 colon cancer cells. The expression level of lincRNA-p21 was significantly (P = .0208) lower in CRC tumor tissue when compared with the paired normal tissue from the same patient. There was no significant correlation of lincRNA-p21 with p53 status (wild-type vs. mutant). Tumors in the rectum showed a higher level of lincRNA-p21 than tumors in the colon (P = .00005). In addition, lincRNA-p21 in patients with stage III tumors was significantly higher than in those with stage I tumors (P = .007). Elevated levels of lincRNA-p21 were significantly associated with higher pT (P = .037 between pT 2 and 3) and vascular invasion (P = .017).

CONCLUSIONS

These results indicate that lincRNA-p21 may contribute to CRC disease progression.

Oxidative DNA damage and β-catenin expression in colorectal cancer evolution

PURPOSE

Oxidative DNA damage is one of the mechanisms associated to initial colorectal carcinogenesis, but how it interacts with β-catenin, an adherence protein related to cancer evolution, is not clear. This study investigates the relationship between oxidative DNA damage and β-catenin expression in normal mucosa and colon tumor tissue (adenoma and adenocarcinoma) in colorectal adenocarcinoma evolution.

METHOD

One hundred and 13 samples were studied. Hematoxylin-eosin determined histological grade. β-Catenin expression was analyzed by immunohistochemistry. The oxidative DNA damage was evaluated using comet assay technique. The coefficient for rejection of the nullity hypothesis was taken to 5 %. Kruskal-Wallis, Spearman test, and partial correlation were used to analyze the data.

RESULTS

There was oxidative DNA damage increase in colorectal cancer evolution (p < 0.01). Histological grade was correlated with oxidative DNA damage (p < 0.01). There were differences in β-catenin expression among normal, adenoma, and adenocarcinoma tissue with progressive increase of β-catenin expression (p < 0.00). Histological grade was correlated to β-catenin expression (p < 0.00). There was a relationship (p < 0.00) between β-catenin and histological grade while controlling for the effect of oxidative DNA damage.

CONCLUSION

The findings of this study make it possible to establish a relationship between oxidative DNA damage and β-catenin expression in normal mucosa and colorectal tumor tissue. Additionally, they show a causal relationship between variations of β-catenin in different tissues analyzed while controlling for the effect of oxidative DNA damage.

S100A8 and S100A9 are associated with colorectal carcinoma progression and contribute to colorectal carcinoma cell survival and migration via Wnt/β-catenin pathway

Background and Objective

S100A8 and S100A9, two members of the S100 protein family, have been reported in association with the tumor cell differentiation and tumor progression. Previous study has showed that their expression in stromal cells of colorectal carcinoma (CRC) is associated with tumor size. Here, we investigated the clinical significances of S100A8 and S100A9 in tumor cells of CRC and their underlying molecular mechanisms.

Methods

Expression of S100A8 and S100A9 in colorectal carcinoma and matching distal normal tissues were measured by reverse transcriptase polymerase chain reaction (RT-PCR), immunohistochemistry and western blot. CRC cell lines treated with the recombinant S100A8 and S100A9 proteins were used to analyze the roles and molecular mechanisms of the two proteins in CRC in vitro.

Results

S100A8 and S100A9 were elevated in more than 50% of CRC tissues and their expression in tumor cells was associated with differentiation, Dukes stage and lymph node metastasis. The CRC cell lines treatment with recombinant S100A8 and S100A9 proteins promoted the viability and migration of CRC cells. Furthermore, the two recombinant proteins also resulted in the increased levels of β-catenin and its target genes c-myc and MMP7. β-catenin over-expression in CRC cells by Adβ-catenin increased cell viability and migration. β-catenin knock-down by Adsiβ-catenin reduced cell viability and migration. Furthermore, β-catenin knockdown also partially abolished the promotive effects of recombinant S100A8 and S100A9 proteins on the viability and migration of CRC cells.

Conclusions

Our work demonstrated that S100A8 and S100A9 are linked to the CRC progression, and one of the underlying molecular mechanisms is that extracellular S100A8 and S100A9 proteins contribute to colorectal carcinoma cell survival and migration via Wnt/β-catenin pathway.

Associations of beta-catenin alterations and MSI screening status with expression of key cell cycle regulating proteins and survival from colorectal cancer

Background

Despite their pivotal roles in colorectal carcinogenesis, the interrelationship and prognostic significance of beta-catenin alterations and microsatellite instability (MSI) in colorectal cancer (CRC) needs to be further clarified. In this paper, we studied the associations between beta-catenin overexpression and MSI status with survival from CRC, and with expression of p21, p27, cyclin D1 and p53, in a large, prospective cohort study.

Methods

Immunohistochemical MSI-screening status and expression of p21, p27 and p53 was assessed in tissue microarrays with tumours from 557 cases of incident CRC in the Malmö Diet and Cancer Study. Chi Square and Spearman’s correlation tests were used to explore the associations between beta-catenin expression, MSI status, clinicopathological characteristics and investigative parameters. Kaplan-Meier analysis and Cox proportional hazards modelling were used to assess the relationship between beta-catenin overexpression, MSI status and cancer specific survival (CSS).

Results

Positive MSI screening status was significantly associated with older age, female sex, proximal tumour location, non-metastatic disease, and poor differentiation, and inversely associated with beta-catenin overexpression. Beta-catenin overexpression was significantly associated with distal tumour location, low T-stage and well-differentiated tumours. Patients with MSI tumours had a significantly prolonged CSS in the whole cohort, and in stage III-IV disease, also in multivariable analysis, but not in stage I-II disease. Beta-catenin overexpression was associated with a favourable prognosis in the full cohort and in patients with stage III-IV disease. Neither MSI nor beta-catenin status were predictive for response to adjuvant chemotherapy in curatively treated stage III patients. P53 and p27 expression was positively associated with beta-catenin overexpression and inversely associated with MSI. Cyclin D1 expression was positively associated with MSI and beta-catenin overexpression, and p21 expression was positively associated with MSI but not beta-catenin overexpression.

Conclusions

Findings from this large, prospective cohort study demonstrate that MSI screening status in colorectal cancer is an independent prognostic factor, but not in localized disease, and does not predict response to adjuvant chemotherapy. Beta-catenin overexpression was also associated with favourable outcome but not a treatment predictive factor. Associations of MSI and beta-catenin alterations with other investigative and clinicopathological factors were in line with the expected.

Virtual slides

The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/8778585058652609

Dysregulation of Wnt/β-catenin signaling in gastrointestinal cancers

Aberrant Wnt/β-catenin signaling is widely implicated in numerous malignancies, including cancers of the gastrointestinal tract. Dysregulation of signaling is traditionally attributed to mutations in Axin, adenomatous polyposis coli, and β-catenin that lead to constitutive hyperactivation of the pathway. However, Wnt/β-catenin signaling is also modulated through various other mechanisms in cancer, including cross talk with other altered signaling pathways. A more complex view of Wnt/β-catenin signaling and its role in gastrointestinal cancers is now emerging as divergent phenotypic outcomes are found to be dictated by temporospatial context and relative levels of pathway activation. This review summarizes the dysregulation of Wnt/β-catenin signaling in colorectal carcinoma, hepatocellular carcinoma, and pancreatic ductal adenocarcinoma, with particular emphasis on the latter two. We conclude by addressing some of the major challenges faced in attempting to target the pathway in the clinic.

Expressions of sFRP1 and β-Catenin in Cervical Cancer

This study aimed to investigate the expressions of secreted frizzled-related protein 1 (sFRP1) and β-catenin in cervical cancer and cervical intraepithelial neoplasia (CIN), and to explore the relationship between both proteins and the prognosis of cervical cancer. Immunohistochemistry was performed to detect the protein expressions of sFRP1 and β-catenin in cervical cancer (n=78), CIN (n=30) and normal cervical tissues (n=20), and the relationships of sFRP1 and β-catenin with the clinicopathological characteristics and prognosis of cervical cancer were analyzed. The positive rate of sFRP1 was 100%, 70% and 33.3% in the normal cervical tissues, CIN and cervical cancer, respectively (P<0.05). The sFRP1 expression was positively correlated with the stage of cervical cancer and lymphatic metastasis (P<0.05). The 5-year survival rate was significantly higher in patients positive for sFRP1 than in those negative for sFRP1 (P<0.05). The rate of abnormal β-catenin expression in the normal cervical tissues, CIN and cervical cancer was 5%, 43.3% and 70.5%, respectively (P<0.05). The abnormal β-catenin expression was positively correlated with the stage of cervical cancer, lymphatic metastasis and pathological grade (P<0.05). The 5-year survival rate was markedly higher in patients with normal β-catenin expression than in those with abnormal β-catenin expression (P<0.05). The sFRP1 expression was negatively related to the β-catenin expression in cervical cancer (r = -0.557, P<0.001). Both sFRP1 and β-catenin play important roles in the initiation and development of cervical cancer, and both proteins can be used as indicators predicting the prognosis of cervical cancer.

Association of CTNNB1 (beta-catenin) alterations, body mass index, and physical activity with survival in patients with colorectal cancer

CONTEXT

Alterations of the WNT signaling pathway and cadherin-associated protein β 1 (CTNNB1 or β-catenin) have been implicated in colorectal carcinogenesis and metabolic diseases.

OBJECTIVE

To test the hypothesis that CTNNB1 activation in colorectal cancer modifies prognostic associations of body mass index (BMI) and level of postdiagnosis physical activity.

DESIGN, SETTING, AND PATIENTS

Two US prospective cohort studies (Nurses' Health Study and the Health Professionals Follow-up Study) were used to evaluate CTNNB1 localization by immunohistochemistry in 955 patients with stage I, II, III, or IV colon and rectal cancer from 1980 through 2004. A Cox proportional hazards model was used to compute the hazard ratio (HR) for mortality, adjusting for clinical and tumor features, including microsatellite instability, CpG island methylator phenotype, level of long interspersed nucleotide element 1 methylation, mutations in KRAS, BRAF, or PIK3CA, and tumor protein p53.

MAIN OUTCOME MEASURES

Colorectal cancer-specific mortality and overall mortality through June 30, 2009.

RESULTS

In obese patients (BMI ≥30), positive status for nuclear CTNNB1 was associated with significantly better colorectal cancer-specific survival (adjusted HR, 0.24 [95% confidence interval {CI}, 0.12-0.49], P <.001 for interaction; 5-year survival: 0.85 for patients with positive nuclear CTNNB1 status vs 0.78 for those with negative status) and overall survival (adjusted HR, 0.56 [95% CI, 0.35-0.90], P = .03 for interaction; 5-year survival: 0.77 for patients with positive nuclear CTNNB1 status vs 0.74 for those with negative status), while CTNNB1 status was not associated with prognosis among nonobese patients (BMI <30). Among patients with negative status for nuclear CTNNB1 and cancer in stages I, II, or III, postdiagnosis physical activity was associated with better colorectal cancer-specific survival (adjusted HR, 0.33 [95% CI, 0.13-0.81], P = .05 for interaction; 5-year survival: 0.97 for ≥18 vs 0.89 for <18 metabolic equivalent task hours/week), while postdiagnosis physical activity was not associated with colorectal cancer-specific survival among patients with positive status for nuclear CTNNB1 (adjusted HR, 1.07 [95% CI, 0.50-2.30]).

CONCLUSIONS

Among obese patients only, activation of CTNNB1 was associated with better colorectal cancer-specific survival and overall survival. Postdiagnosis physical activity was associated with better colorectal cancer-specific survival only among patients with negative status for nuclear CTNNB1. These molecular pathological epidemiology findings suggest that the effects of alterations in the WNT-CTNNB1 pathway on outcome are modified by BMI and physical activity.

L1 cell adhesion molecule as a novel independent poor prognostic factor in gallbladder carcinoma

Gallbladder carcinoma is a lethal malignancy and is hard to cure by current treatment. Thus, identification of molecular prognostic markers to predict gallbladder carcinoma as therapeutic targets is urgently needed. Recent studies have demonstrated that L1 cell adhesion molecule is associated with the prognosis of variable malignancy. Here, we investigated L1 cell adhesion molecule expression in gallbladder carcinoma and its prognostic significance. In this study, we examined L1 cell adhesion molecule expression in tumor specimens from 69 patients with gallbladder carcinoma by immunohistochemistry and analyzed the correlation between L1 cell adhesion molecule expression and clinicopathologic factors or survival. L1 cell adhesion molecule was not expressed in the normal epithelium of the gallbladder but in 63.8% of gallbladder carcinomas, remarkably at the invasive front of the tumors. In addition, L1 cell adhesion molecule expression was significantly associated with high histologic grade, advanced pathologic T stage and clinical stage, and positive venous/lymphatic invasion. Multivariate analyses showed that L1 cell adhesion molecule expression (hazard ratio, 3.503; P = .028) and clinical stage (hazard ratio, 3.091; P = .042) were independent risk factor for disease-free survival. L1 cell adhesion molecule expression in gallbladder carcinoma was significantly correlated with tumor progression and unfavorable clinicopathologic features. L1 cell adhesion molecule expression was an independent poor prognostic factor for disease-free survival in patients with gallbladder carcinoma. Taken together, our findings suggest that L1 cell adhesion molecule expression could be used as a novel prognostic factor for patient survival and might be a potential therapeutic target in gallbladder carcinomas.

Cell surface markers in colorectal cancer prognosis

The classification of colorectal cancers (CRC) is currently based largely on histologically determined tumour characteristics, such as differentiation status and tumour stage, i.e., depth of tumour invasion, involvement of regional lymph nodes and the occurrence of metastatic spread to other organs. These are the conventional prognostic factors for patient survival and often determine the requirement for adjuvant therapy after surgical resection of the primary tumour. However, patients with the same CRC stage can have very different disease-related outcomes. For some, surgical removal of early-stage tumours leads to full recovery, while for others, disease recurrence and metastasis may occur regardless of adjuvant therapy. It is therefore important to understand the molecular processes that lead to disease progression and metastasis and to find more reliable prognostic markers and novel targets for therapy. This review focuses on cell surface proteins that correlate with tumour progression, metastasis and patient outcome, and discusses some of the challenges in finding prognostic protein markers in CRC.

Current and emerging concepts in tumour metastasis

Disseminated cancer accounts for most deaths due to malignancy. Despite this, research has focused predominantly on tumour development and progression at the primary site. Recently, attention has shifted towards the field of tumour metastasis. Several new and exciting concepts that have emerged in the past few years may shed light on this complex area. The established canonical theory of tumour metastasis, as a process emerging from a stepwise accumulation of genetic events fuelled by clonal evolution, has been challenged. New evidence suggests that malignant cells can disseminate at a much earlier stage than previously recognized in tumourigenesis. These findings have direct relevance to clinical practice and shed new light on tumour biology. Gene-profiling studies support this theory, suggesting that metastatic ability may be an innate property shared by the bulk of cells present early in a developing tumour mass. There is a growing recognition of the importance of host factors outside the primary site in the development of metastatic disease. The role of the 'pre-metastatic niche' is being defined and with this comes a new understanding of the function of bone marrow-derived progenitor cells in directing the dissemination of malignant cells to distant sites. Current research has highlighted the crucial roles played by non-neoplastic host cells within the tumour microenvironment in regulating metastasis. These new concepts have wide-ranging implications for our overall understanding of tumour metastasis and for the development of cancer therapeutics.

Wilms' tumor 1 gene (WT1) is overexpressed and provides an oncogenic function in pediatric nephroblastomas harboring the wild-type WT1

Wilms' tumor 1 gene (WT1) is known to be a tumor suppressor gene in the subset of nephroblastomas that harbors WT1 mutations. However, its role in nephroblastomas without mutations remains unclear. This study aimed to evaluate the expression of WT1 and its potential oncogenic role in pediatric nephroblastoma with wild-type WT1. A total of 24 nephroblastomas were studied for WT1 mRNA expression by quantitative reverse-transcription polymerase chain reaction. The expression levels were compared between nephro-blastomas with and without WT1 mutations, as well as to normal kidney tissue, other pediatric renal tumors and neuroblastomas. Immunohistochemistry was used to evaluate expression patterns at the tissue level. Post-transcriptional inhibition of WT1 was performed in primary cultures of wild-type nephroblastoma using WT1 siRNA. The average WT1 expression level in nephroblastoma tissue was significantly higher than that in normal kidney tissue and neuroblastomas. Expression at the mRNA level was not different between nephroblastomas with WT1 mutations (4 cases) and those with wild-type WT1 (20 cases). However, while WT1 immunoreactivity was positive in all of the nephroblastoma components in the tumors with wild-type WT1, the protein expression was weaker and limited to stromal components in the tumors with mutated WT1, where it co-localized with β-catenin nuclear accumulation. The post-transcriptional inhibition of WT1 resulted in growth retardation and a significantly increased apoptotic fraction. Our study found overexpression of the WT1 gene in pediatric nephroblastomas with wild-type WT1. Moreover, the study suggests an oncogenic role of WT1 in this tumor subset.

Prognostic role of beta-catenin and p53 expression in the metastatic progression of sporadic colorectal cancer

Beta-catenin and p53 play key roles in tumorigenesis. The relationships between these 2 signaling pathways and their contribution to colorectal cancer metastatic progression have not been completely elucidated. We analyzed 141 cases of primary sporadic colorectal cancer, 45 matched metastases, and 80 samples of normal mucosa by immunohistochemistry on paraffin-embedded specimens. The expression profiles were also related to patients' clinicopathologic features and 5-year survival. In primary tumors, beta-catenin immunoreactivity was nuclear (27%), predominantly membrane/cytosolic (46.0%) or negative (27%). This latter subgroup was strongly related to microsatellite instability, in particular to MLH-1 deficiency. Remarkably, beta-catenin membrane/cytosolic expression in primary tumors was reduced in the corresponding matched metastases. p53 showed a significant increase in immunoreactivity in (66.7%), whereas it was negative in (33.3%) of tumors. When we considered the expression of both genes, the combination of negative beta-catenin and positive p53 nuclear staining (21%) was strongly related to a higher frequency of liver metastases. Such an association was significantly related to a worse prognosis than any other combination. In a multivariate analysis, beta-catenin and distant metastases were independent prognostic markers. We suggest that a combination of low beta-catenin and high p53 expression in primary colorectal cancers may be a prognostic factor in predicting the progression of the disease, the occurrence of metastasis, and a more severe outcome.

Immunohistological evidence for Wnt-signaling activation in Peutz-Jeghers polyposis

OBJECTIVE

Molecular pathogenesis of gastrointestinal polyposis in Peutz-Jegher's syndrome (PJS) has been linked to the loss-of-function mutation of LKB1. Recent functional genetic studies have pointed out that LKB1 plays a physiological role in controlling the Wnt-signaling pathway and activation of the pathway as a consequence of LKB1 haploinsufficiency might be responsible for the development of harmatomatous polyps. This study aimed to look for immunohistochemical evidence of Wnt-signaling activation in PJS polyps.

METHOD

Beta-catenin immunohistochemistry patterns were evaluated in gastrointestinal polyps from five cases of PJS. All patients were also evaluated for germline mutations of LKB1 and somatic mutations of beta-catenin in the polyps.

RESULTS

Four of the five cases had germline mutations of LKB1, including two novel mutations, a one-base insertion at codon 53 and a large deletion encompassing exon 3 (codon 136-155). PJS polyps from all patients showed generalized membrane and cytoplasmic localizations of beta-catenin along the mucosal endothelium. Polyps from two cases with LKB1 mutations revealed moderate-intensity nuclear staining in approximately 20 and 70% of the polyps.

CONCLUSION

The study offers additional evidence of Wnt-signaling activation in PJS polyp development at the tissue level, although the degree of up-regulation was not as high as has been found in Wnt-associated neoplasms.

Short hairpin RNA-mediated downregulation of the Pokemon gene suppresses proliferation and promotes apoptosis in HepG2 cells

AIM: To construct recombinant plasmids containing short hairpin RNA (shRNA) targeting the Pokemon gene and investigate the effects of shRNA-mediated downregulation of the Pokemon gene on the proliferation and apoptosis of HepG2 cells.

METHODS: Three shRNAs were designed according to the coding sequence of the Pokemon gene and used to construct recombinant plasmids. The recombinant plasmids were transfected into HepG2 cells using Lipofectamine 2000. The expression of Pokemon mRNA and protein was detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot, respectively. Cellular proliferation was measured by methyl thiazolyl tetrazolium (MTT) assay. Apoptosis was analyzed by flow cytometry. The expression of H-ras and β-catenin genes was detected by RT-PCR.

RESULTS: Three recombinant plasmids were successfully constructed. The expression of Pokemon mRNA and protein was obviously downregulated in HepG2 cells transfected with the recombinant plasmids. The best silencing effect was achieved in cells transfected with the pshRNA2 plasmid. The expression levels of Pokemon mRNA and protein were downregulated by 75.2% and 72.61%, respectively. MTT assay indicated that pshRNA2 transfection could inhibit cellular proliferation and promote apoptosis. After pshRNA2 transfection, the expression of H-ras mRNA was downregulated (P < 0.05) in HepG2 cells though no significant change was observed in β-catenin expression.

CONCLUSION: The recombinant plasmids containing shRNA targeting the Pokemon gene can specifically downregulate Pokemon expression. The Pokemon protein can promote proliferation and inhibit apoptosis in HepG2 cells possibly via downregulation of H-ras expression.