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

Primary urethral adenocarcinoma harbors recurrent KRAS and EGFR alterations

Primary urethral adenocarcinoma is an extremely rare malignancy with an unclear pathogenesis. Previously, we reported 4 brachytherapy-associated (BA) urethral mucinous adenocarcinomas that developed following treatment for prostate cancer. In the present study, we report one additional BA and 3 radiation-independent (RI) urethral adenocarcinomas. The aim of this study is to explore the molecular alterations and to compare the clinicopathologic features. RNA sequencing was performed on 5 tumors, and a next-generation sequencing (NGS)-based fusion assay was used to identify gene fusions in 6 tumors. Additionally, NGS-based targeted genomic DNA sequencing was employed to analyze one metastatic BA tumor and one metastatic RI tumor. The 8 patients had a mean age of 67 (range: 37-87) years, with one being female in the RI cohort. Cystoscopy revealed the following urethral findings: a papillary lesion (4/7), mass causing obstruction (1/7) and irregular friable tissue (2/7). Seven patients underwent urethrectomy with cystectomy/prostatectomy/hysterectomy. The mean tumor size was 3.4 cm (range: 1.5-6.5). Adenocarcinoma in situ was noted in 5 tumors. All 5 BA tumors originated from the prostatic urethra, with 4 showing mucinous morphology and one enteric morphology, and showed moderate to poor differentiation and tumor stages of pT2 (2/4), pT3 (1/3) and pT4 (1/4). Two patients developed metastasis, one at 3.3 and one at 4.2 years after diagnosis, and all patients were alive at a median follow-up of 4.5 (range: 2-14) years. In contrast, 3 RI tumors arose from bulbar, prostatic, or female mid/distal urethra, presenting as enteric, mucinous, and not otherwise specified (NOS) subtypes, with well to moderate differentiation and a tumor stage of pT4 (2/2). Two died of the disease, while one was alive without disease at a median follow-up of 4 (range: 2.2-14.5) years. All tumors were diffusely positive for CK20, CDX2 (7/7), and AMACR (3/3), and lacked nuclear β-catenin expression (5/5). Most expressed CK7 (5/7). KRAS mutations (p.Gly12Val and p.Gly13Asp) were observed in one BA mucinous tumor and one RI NOS tumor with the p.Gly13Asp mutation also detected in the metastatic RI tumor. The EGFR p.Ser784Phe mutation was detected in one RI enteric tumor. TP53 p.Val172Phe, CDKN2A p.Leu32_Leu37del, and amplifications of EGFR and MDM2, were identified in a metastatic BA enteric tumor. No fusion transcripts were identified. In conclusion, urethral adenocarcinoma harbors recurrent KRAS and EGFR alterations, independent of prior radiotherapy. RI tumors appear to be associated with a worse prognosis compared to BA tumors.

Aberrant β-Catenin Expression and Its Association With Epithelial-Mesenchymal Transition and Clinical Outcomes of Colorectal Cancer

Background Colorectal cancer (CRC) is a significant global health challenge with high mortality rates. Dysregulation of β-catenin, epithelial-mesenchymal transition (EMT), and adenomatous polyposis coli (APC) are crucial in CRC development. Mutations in the APC gene lead to aberrant β-catenin expression, a key player in CRC pathogenesis. β-catenin not only influences canonical Wnt signaling but also regulates EMT. This study investigated the correlation between APC mutations, β-catenin dysregulation, and EMT induction in CRC. Methodology Tissue samples from 96 CRC patients and 40 para-cancerous normal tissues were collected and subjected to immunohistochemistry to assess β-catenin, E-cadherin, ZEB1, Snail, and vimentin expression. Genomic DNA was extracted and analyzed for APC mutations. Next-generation sequencing was employed for data analysis. Results Aberrant β-catenin expression was found in 82.3% of CRC cases and correlated with advanced clinicopathological factors. Aberrant β-catenin expression was associated with age (p=0.01), tumor invasion depth (p=0.03), nodal/distant metastasis (p=0.001 and 0.004), and vascular invasion (p=0.001). Aberrant β-catenin was correlated with EMT status. A positive correlation was observed between aberrant β-catenin expression and ZEB1 (p=0.001), Snail (p=0.001), vimentin (p=0.001), and loss of membranous E-cadherin (p=0001). Coexistence of aberrant β-catenin and EMT markers was associated with advanced CRC progression. Cancerous tissues displayed higher aberrant β-catenin and EMT markers expression than para-cancerous tissues. APC mutations were present in 59.3% of cases, with 91.2% of mutated APC cases showing aberrant β-catenin expression. The coexistence of APC mutation and aberrant β-catenin expression was correlated with the clinical outcomes of CRC patients. Mutated APC cases exhibited significantly increased EMT marker expression. Conclusion This study underscores the importance of aberrant β-catenin expression in CRC progression, linked to APC mutations and EMT induction. Understanding these relationships could aid in developing targeted therapies for CRC.

Disruption of the crypt niche promotes outgrowth of mutated colorectal tumor stem cells

Recent data establish a logarithmic expansion of leucine rich repeat containing G protein coupled receptor 5–positive (Lgr5⁺) colonic epithelial stem cells (CESCs) in human colorectal cancer (CRC). Complementary studies using the murine 2-stage azoxymethane–dextran sulfate sodium (AOM-DSS) colitis-associated tumor model indicate early acquisition of Wnt pathway mutations drives CESC expansion during adenoma progression. Here, subdivision of the AOM-DSS model into in vivo and in vitro stages revealed DSS induced physical separation of CESCs from stem cell niche cells and basal lamina, a source of Wnt signals, within hours, disabling the stem cell program. While AOM delivery in vivo under non-adenoma-forming conditions yielded phenotypically normal mucosa and organoids derived thereof, niche injury ex vivo by progressive DSS dose escalation facilitated outgrowth of Wnt-independent dysplastic organoids. These organoids contained 10-fold increased Lgr5⁺ CESCs with gain-of-function Wnt mutations orthologous to human CRC driver mutations. We posit CRC originates by niche injury–induced outgrowth of normally suppressed mutated stem cells, consistent with models of adaptive oncogenesis.

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.

The relationship between β-catenin and patient survival in colorectal cancer systematic review and meta-analysis

β-catenin is a key component of Wnt signalling, which plays a crucial role in CRC progression. Therefore, a meta-analysis was performed to assess the prognostic value of β-catenin expression in CRC patients. PubMed and Web of Science were searched for relevant publications referring to the association between β-catenin expression and outcome of CRC patients. Review Manager version 5.4 was employed to analysis data from 28 eligible studies (containing 5475 patients). Of these, 6 provided data on DFS, 6 provided data on CSS and 18 reports provided data on OS. High nuclear β-catenin expression was significantly associated with poorer DFS, CSS and OS in patients with CRC whereas, low membranous β-catenin expression was associated to poor OS. In conclusion, β-catenin has prognostic value and potential as a biomarker to stratify patients with CRC. However, further work with high quantity tissue cohorts and patient data is required to confirm this conclusion.

Impact of Preanalytical Factors on the Measurement of Tumor Tissue Biomarkers Using Immunohistochemistry

Analysis of formalin-fixed paraffin-embedded (FFPE) tissue by immunohistochemistry (IHC) is commonplace in clinical and research laboratories. However, reports suggest that IHC results can be compromised by biospecimen preanalytical factors. The National Cancer Institute's Biospecimen Preanalytical Variables Program conducted a systematic study to examine the potential effects of delay to fixation (DTF) and time in fixative (TIF) on IHC using 24 cancer biomarkers. Differences in IHC staining, relative to controls with a DTF of 1 hr, were observed in FFPE kidney tumor specimens after a DTF of ≥2 hr. Reductions in H-score and/or staining intensity were observed for c-MET, p53, PAX2, PAX8, pAKT, and survivin, whereas increases were observed for RCC1, EGFR, and CD10. Prolonged TIF of 72 hr resulted in significantly reduced H-scores of CD44 and c-Met in kidney tumor specimens, compared with controls with 12-hr TIF. An elevated probability of altered staining intensity due to DTF was observed for nine antigens, whereas for prolonged TIF an elevated probability was observed for one antigen. Results reported here and elsewhere across tumor types and antigens support limiting DTF to ≤1 hr when possible and fixing tissues in formalin for 12-24 hr to avoid confounding effects of these preanalytical factors on IHC.

Forkhead box protein O3a promotes glioma cell resistance to temozolomide by regulating matrix metallopeptidase and β-catenin

Glioblastoma multiforme (GBM) is the most common type of malignant brain tumor. GBM is currently treated with temozolomide (TMZ), although patients often exhibit resistance to this agent. Although several mechanisms underlying the resistance of GBM to TMZ have been identified, the combination of these mechanisms is not sufficient to fully account for this phenomenon. Our previous study demonstrated that knocking down the Forkhead box protein O3a (FoxO3a) gene, a member of the FoxO subfamily of transcription factors, resulted in glioma cell sensitization to TMZ, accompanied by reduced levels of nuclear β-catenin. The aim of the present study was to specify how FoxO3a and β-catenin are implicated in glioma cell TMZ resistance. Using the U87 and U251 parental cell lines (also designated as sensitive cell lines) and corresponding resistant cell lines (U87-TR and U251-TR, generated by repeated TMZ treatments), coupled with a combined knockdown/overexpression strategy, it was revealed that FoxO3a or β-catenin overexpression in TMZ-treated U87 and U251 cells markedly increased cellular proliferation; co-expression of both FoxO3a and β-catenin resulted in the highest increase. Knockdown of either FoxO3a or β-catenin in U87-TR and U251-TR cells led to a significant decrease in cell viability, which was rescued by the re-expression of FoxO3a in FoxO3a-knockdown cells. Subsequent experiments demonstrated that, in U87-TR and U251-TR cells, FoxO3a knockdown significantly reduced the protein levels of matrix metallopeptidase (MMP)9, while overexpression of FoxO3a in U87 and U251 cells enhanced the nuclear accumulation of β-catenin, concomitantly with an increase in MMP9 levels. Furthermore, MMP9 knockdown markedly reduced the levels of nuclear β-catenin. Collectively, the findings of the present study suggest that FoxO3a may regulate the nuclear accumulation of β-catenin by modulating MMP9 expression, thereby rendering glioblastoma cells resistant to TMZ, and may provide unique molecular insights into the mechanisms underlying the development of TMZ resistance in GBM.

Differential Wnt-β- catenin pathway activation in HPV positive and negative oral epithelium is transmitted during head and neck tumorigenesis: clinical implications

The aim of this study is to understand the association of HPV infection and wnt-β-catenin self-renewal pathway in development of head and neck squamous cell carcinoma (HNSCC). For this reason, the molecular profiles (methylation/deletion/expression) of antagonists (SFRP1/2 and DKK1), agonists (FZD7 and LRP6) and effector protein β-catenin of the pathway were analyzed in HPV positive/negative oral epithelium at first, followed by its changes during development of the tumor along with correlations with different clinico-pathological parameters. HPV infection alone or in combination with tobacco habit could activate p- β-catenin expression in basal/parabasal layers of oral epithelium through high expression of FZD7 and significant down regulation of SFRP1/2 through promoter hypermethylation due to over expression of DNMT1 with ubiquitous down regulation of DKK1 and up-regulation of LRP6. This phenomenon has been seen in respective HPV positive and negative HNSCC tumors with additional deletion/microsatellite size alterations in the antagonists. Overall alterations (methylation/deletion) of SFRP1/2, DKK1 gradually increased from Group I (HPV-/Tobacco-) to Group IV(HPV+/Tobacco+) tumors, leading to the worst prognosis of the patients. Thus, the transmission of differentially activated wnt-β-catenin pathway from HPV positive/negative basal/parabasal layers of oral epithelium to HNSCC tumors determines differences in molecular pathogenesis of the disease.

β-catenin activation down-regulates cell-cell junction-related genes and induces epithelial-to-mesenchymal transition in colorectal cancers

WNT signaling activation in colorectal cancers (CRCs) occurs through APC inactivation or β-catenin mutations. Both processes promote β-catenin nuclear accumulation, which up-regulates epithelial-to-mesenchymal transition (EMT). We investigated β-catenin localization, transcriptome, and phenotypic differences of HCT116 cells containing a wild-type (HCT116-WT) or mutant β-catenin allele (HCT116-MT), or parental cells with both WT and mutant alleles (HCT116-P). We then analyzed β-catenin expression and associated phenotypes in CRC tissues. Wild-type β-catenin showed membranous localization, whereas mutant showed nuclear localization; both nuclear and non-nuclear localization were observed in HCT116-P. Microarray analysis revealed down-regulation of Claudin-7 and E-cadherin in HCT116-MT vs. HCT116-WT. Claudin-7 was also down-regulated in HCT116-P vs. HCT116-WT without E-cadherin dysregulation. We found that ZEB1 is a critical EMT factor for mutant β-catenin-mediated loss of E-cadherin and Claudin-7 in HCT116-P and HCT116-MT cells. We also demonstrated that E-cadherin binds to both WT and mutant β-catenin, and loss of E-cadherin releases β-catenin from the cell membrane and leads to its degradation. Alteration of Claudin-7, as well as both Claudin-7 and E-cadherin respectively caused tight junction (TJ) impairment in HCT116-P, and dual loss of TJs and adherens junctions (AJs) in HCT116-MT. TJ loss increased cell motility, and subsequent AJ loss further up-regulated that. Immunohistochemistry analysis of 101 CRCs revealed high (14.9%), low (52.5%), and undetectable (32.6%) β-catenin nuclear expression, and high β-catenin nuclear expression was significantly correlated with overall survival of CRC patients (P = 0.009). Our findings suggest that β-catenin activation induces EMT progression by modifying cell-cell junctions, and thereby contributes to CRC aggressiveness.

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.

FoxO3a induces temozolomide resistance in glioblastoma cells via the regulation of β-catenin nuclear accumulation

Glioblastoma multiforme (GBM), the most common malignant brain tumor, is currently treated with temozolomide (TMZ), but GBM often exhibits resistance to TMZ. Although several mechanisms underlying GBM resistance to TMZ have been identified, these mechanisms are yet to fully explain how GBM gains resistance to TMZ. Our previous work has shown that FoxO3a, a member of the FoxO subfamily of transcription factors, promotes glioma cell proliferation and invasion. In this study, we sought to determine whether FoxO3a participates in TMZ resistance in GBM cells. Parental cell lines (also designated as sensitive cell lines) U87-MG and U251-MG, as well as the corresponding resistant cell lines U87-TR and U251-TR (generated by repeated TMZ treatments), were subjected to western blot analysis. Our results showed that the resistant cells (both U87-TRand U251-TR) exhibited higher levels of FoxO3a and β-catenin relative to their corresponding sensitive counterparts. Depletion of FoxO3a in the resistant cells enhanced the cytotoxic effect of TMZ. Further investigation showed that FoxO3a depletion did not affect the total protein level of β-catenin, but otherwise markedly reduced the nuclear β-catenin level. Taken together, these findings strongly support that FoxO3a renders GBM cells resistant to TMZ treatment, at least in part, through the regulation of β-catenin nuclear accumulation.

α-methylacyl-CoA racemase (AMACR) expression in chordomas differentiates them from chondrosarcomas

Aims: Chordomas and chondrosarcomas are malignant mesenchymal tumours with overlapping morphological and immunohistochemical (IHC) characteristics. Our aim was to evaluate the IHC expression of α-methylacyl-CoA racemase (AMACR/P504S), β-catenin and E-cadherin in chordomas relative to chondrosarcomas and assess the utility of these markers for differential diagnosis. Methods: Archival sections of 18 chordomas, 19 chondrosarcomas and 10 mature cartilage samples were immunostained and scored for AMACR, β-catenin and E-cadherin and the relative differential capacity of each marker was calculated. In addition, AMACR mRNA level was assessed in 5 chordomas by RT-PCR and evaluated by comparative C_T method. Results: AMACR and β-catenin stained 88.9% and 94.1% of the chordomas respectively, 21.1% and 10.5% of the chondrosarcomas correspondingly and none of the mature cartilage samples. E-cadherin stained positively 82.4% of the chordomas, 36.8% of the chondrosarcomas and 42.9% of the mature cartilage cases. Both AMACR and β-catenin showed statistically significant difference between chordomas and chondrosarcomas (p < 0.001 for both), unlike E-cadherin. AMACR was detected at the mRNA level. Conclusions: AMACR is expressed in most of the chordomas but only in a minority of chondrosarcomas. AMACR may serve as IHC marker of chordoma with differentiating ability comparable to that of β-catenin.

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.

Assessment Of Plasma B-Catenin Concentration As Biomarker Of Thyroid Cancer

New diagnostic methods for thyroid diseases are still being searched for. Immunohistochemical diagnosis is expanded by the introduction of new biomarkers including ß-catenin (B-Cat). Associations are indicated between the cellular expression of this biomarker and tumor stage, nodal metastases and the degree of tumor cell differentiation. Reports are scarce regarding the plasma level of this biomarker in malignant neoplastic diseases. The aim of the study was to analyze the plasma B-Cat concentration and the possibility of it use in the diagnostics of patients with nodular goiter and papillary thyroid carcinoma.

MATERIAL AND METHODS

Plasma B-Cat concentration was determined in 64 patients with goiter and 15 healthy volunteers. The final histopathological examination revealed 41 cases of papillary thyroid carcinoma (PTC) and 13 cases of nodular goiter (NG).

RESULTS

A significant increase in B-Cat (p <0.05) in both groups compared to the control group. No differences in the concentrations of biomarker was demonstrated between the PTC and NG groups. After determining the AUC for the tested biomarker, the B-Cat ratio of the area value 0.721 was the strong diagnostic test.

CONCLUSIONS

Changes in the plasma B-Cat concentration can be the biomarker of thyroid cancer but it cannot be used for the detection of papillary thyroid carcinoma because of concomitant tumor-like lesions in the thyroid gland.

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.

Expression and mutation pattern of β-catenin and adenomatous polyposis coli in colorectal cancer patients

BACKGROUND AND AIMS

β-Catenin and adenomatous polyposis coli (APC) are major components of the Wnt pathway. This study aimed to investigate the expression of β-catenin and APC in tumors and lymph nodes in colorectal cancer (CRC) patients and the mutational spectrum of the genes coding these proteins.

METHODS

Expression of APC and β-catenin was examined in 124 tumors and 41 lymph nodes. Exon 3 of CTNNB1 and the mutation cluster region (MCR) in exon 15 of the APC gene were screened for mutation by PCR-sequencing.

RESULTS

Nuclear/cytoplasmic immunostaining of β-catenin was detected in 58.1 and 48.8% in tumors and lymph nodes, respectively. In tumors, abnormal expression of β-catenin correlated with tumor size and with those in lymph nodes. Membranous β-catenin expression occurred in 41.9 and 14.6% of tumors and lymph nodes, respectively. In tumors, lack of membranous β-catenin correlated with high invasiveness and metastatic potential. Positive immunostaining for APC was observed in 2 and 14% of tumors and lymph nodes, respectively. Overexpression in nucleus/cytoplasm and lack of membranous β-catenin significantly correlated with a reduced overall survival. Among 25 tumors, four harbour mutation in Ser33 and Ser47 and overexpress the β-catenin in the nucleus/cytoplasm. Mutations were identified in the APC gene in 13 tumors and six mutations were novel.

CONCLUSIONS

Positive association between aberrant expression of β-catenin in the nucleus/cytoplasm of tumors and lymph nodes was observed. Nucleus/cytoplasmic accumulation of β-catenin and loss of membranous expression are related to reduced survival and could serve as a candidate prognostic predictor.

Glucagon phosphorylates serine 552 of β-catenin leading to increased expression of cyclin D1 and c-Myc in the isolated rat liver

In the last 20 years the prevalence of metabolic disorders, in particular type 2 diabetes (T2D), has more than doubled. Recently, a strong link between T2D and cancer, in particularly liver cancer has been reported. However, the mechanism connecting the development of type 2 diabetes and cancer remains unknown. One of the biggest drivers of liver cancer is alterations in the Wnt/β-catenin pathway. In this study, we aimed to identify the effect of glucagon on β-catenin in the isolated rat liver. We found glucagon, which is substantially raised in patients with T2D, rapidly phosphorylates β-catenin on serine 552 that is associated with increased expression of genes cyclin D1 (CCND1) and c-Myc (MYC), which are known to be involved in liver cancer. This finding may explain the increased risk of liver cancer in people with T2D.

The expression of microRNA-375 in plasma and tissue is matched in human colorectal cancer

Background

MicroRNAs (miRNAs) offer great potential as cancer biomarkers. The importance of miRNAs profiling in tissue and body fluids in colorectal cancer (CRC) have been addressed respectively in many studies. The purpose of our study is to systematically assess the expression of miRNAs in cancer tissue and matched plasma samples and to evaluate their usefulness as minimally invasive diagnostic biomarkers for the detection of CRC.

Methods

The study was divided into two phases: firstly, qRT-PCR based TaqMan Low Density MiRNA Arrays (TLDAs) was used to screen the differentially expressed miRNAs in 6 plasma samples of CRC patients and 6 healthy controls. Secondly, marker validation by stem-loop reverse transcription real-time PCR using an independent set of paired cancer tissues (n = 88) and matched plasma samples (CRC, n = 88; control, n = 40). Correlation analysis was determined by Pearson’s test. Receiver operating characteristic curve analyses were applied to obtain diagnostic utility of the differentially expressed miRNAs. Target gene prediction and signal pathway analyses were used to predict the function of miRNAs.

Results

TLDAs identified 42 miRNAs, which were differentially expressed in patients and healthy individuals. Five of them (miR-375, miR-150, miR-206, miR-125b and miR-126*) were chosen to be validated in plasma and tissue samples. The results indicated that for plasma sample, miR-375 (p < 0.0001) and miR-206 (p = 0.0002) were dysregulated and could discriminate CRC patients from healthy controls. For tissue samples, miR-375 (p < 0.0001), miR-150 (p < 0.0001), miR-125b (p = 0.0065) and miR-126*(p = 0.0009) were down-regulated. miR-375 was significantly down-regulated and positively correlated in both tissue and plasma samples (r = 0.4663, p = 0.0007). Gene ontology and signal pathway analyses showed that most of the target genes that were regulated by miR-375 were involved in some critical pathways in the development and progression of cancer.

Conclusions

Our results indicate that the down-regulation of miR-375 in plasma and tissue is matched in CRC. Moreover, bioinformatics prediction revealed miR-375 association with some critical signal pathways in the development and progression of CRC. Therefore, plasma miR-375 holds great promise to be an alternative tissue biomarker for CRC detection.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-714) contains supplementary material, which is available to authorized users.

GSK-3β-regulated N-acetyltransferase 10 is involved in colorectal cancer invasion

PURPOSE

NAT10 (N-acetyltransferase 10) is a nucleolar protein, but may show subcellular redistribution in colorectal carcinoma. In this study, we evaluated membranous staining of NAT10 in colorectal carcinoma and its clinical implications, and explored the mechanism of regulation of NAT10 redistribution.

EXPERIMENTAL DESIGN

The expression and subcellular redistribution of NAT10, β-catenin, E-cadherin, and GSK-3β were evaluated by immunohistochemistry in 222 cases of colorectal carcinoma. Regulation of NAT10 and its influence on cell motility were analyzed with inhibitors of GSK-3β, transfection of wild-type or kinase-inactivated GSK-3β, or expression of various domains of NAT10, and evaluated with immunofluorescence, Western blotting, and Transwell assays.

RESULTS

NAT10 localized mainly in the nucleoli of normal tissues, and was redistributed to the membrane in cancer cells, particularly at the invasive "leading edge" of the tumor. This correlated well with nuclear accumulation of β-catenin (P<0.001; χ2=68.213). In addition, NAT10 membrane staining reflected the depth of invasion and tendency to metastasize (all P values<0.001), and was associated with a poorer prognosis (P=0.023; χ2=5.161). Evaluation of the mechanism involved demonstrated that subcellular redistribution of NAT10 may result from its increased stability and nuclear export, which is brought about by inhibition of GSK-3β. Moreover, redistribution of NAT10 induces alteration of cytoskeletal dynamics and increases cancer cell motility.

CONCLUSION

The subcellular redistribution of NAT10 can be induced by decreases in GSK-3β activity. This redistribution increases cancer cell motility, and is, thus, correlated with invasive potential and poorer clinical outcome. This finding suggests that NAT10 may be a useful prognostic marker and potential therapeutic target in colorectal carcinoma.

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.

Potential of long-chain n-3 polyunsaturated fatty acids in melanoma prevention

The possible antineoplastic activity of dietary long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFAs) has been supported by ample preclinical studies that have identified a number of molecular factors and pathways affected by these fatty acids and involved in cell growth, apoptosis, invasion, and angiogenesis. The aim of this critical review is to assess the current state of knowledge on the potential anticancer effects of LC n-3 PUFAs against malignant melanoma, one of the most common cancers among Western populations. The results of preclinical as well as human observational and interventional studies investigating the effects of LC n-3 PUFAs in melanoma were examined. Overall, the analysis of the literature reveals that, even though a large body of information is available, further effort is needed to identify the main molecular targets of LC n-3 PUFAs in melanoma. Moreover, additional well-designed human observational studies are essential to shed further light on the issue. The results of these studies could provide support and specific information for the development of clinical studies, especially those performed in combination with conventional or innovative antineoplastic therapies.

Preoperative chemoradiotherapy in rectal cancer induces changes in the expression of nuclear β-catenin: prognostic significance

BACKGROUND

Preoperative chemoradiotherapy (CRT) is the cornerstone of treatment for locally advanced rectal cancer (LARC). Although high local control is achieved, overall rates of distant control remain suboptimal. Colorectal carcinogenesis is associated with critical alterations of the Wnt/β-catenin pathway involved in proliferation and survival. The aim of this study was to assess whether CRT induces changes in the expression of β-catenin/E-cadherin, and to determine whether these changes are associated with survival.

METHODS

The Immunohistochemical expression of nuclear β-catenin and membranous E-cadherin was prospectively analysed in tumour blocks from 98 stage II/III rectal cancer patients treated with preoperative CRT. Tumour samples were collected before and after CRT treatment. All patients were treated with pelvic RT (46-50 Gy in 2 Gy fractions) and 5-fluorouracil (5FU) intravenous infusion (225 mg/m2) or capecitabine (825 mg/m2) during RT treatment, followed by total mesorectal excision (TME). Disease-free survival (DFS) was analysed using the Kaplan-Meier method and a multivariate Cox regression model was employed for the Multivariate analysis.

RESULTS

CRT induced significant changes in the expression of nuclear β-catenin (49% of patients presented an increased expression after CRT, 17% a decreased expression and 34% no changes; p = 0.001). After a median follow-up of 25 months, patients that overexpressed nuclear β-catenin after CRT showed poor survival compared with patients that experienced a decrease in nuclear β-catenin expression (3-year DFS 92% vs. 43%, HR 0.17; 95% CI 0.03 to 0.8; p = 0.02). In the multivariate analysis for DFS, increased nuclear β-catenin expression after CRT almost reached the cut-off for significance (p = 0.06).

CONCLUSIONS

In our study, preoperative CRT for LARC induced significant changes in nuclear β-catenin expression, which had a major impact on survival. Finding a way to decrease CRT resistance would significantly improve LARC patient survival.

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.

Wnt3a expression is associated with MMP-9 expression in primary tumor and metastatic site in recurrent or stage IV colorectal cancer

Background

The wnt/β-catenin signaling pathway is known to affect in cancer oncogenesis and progression by interacting with the tumor microenvironment. However, the roles of wnt3a and wnt5a in colorectal cancer (CRC) have not been thoroughly studied. In the present study, we investigated the expression of wnt protein and the concordance rate in primary tumor and metastatic sites in CRC. To determine the relationship of wnt proteins with invasion related protein, we also analyzed the association between wnt protein expression and the expression of matrix metalloproteinase-9 (MMP-9) and vascular endothelial growth factor receptor-2 (VEGFR-2).

Methods

Tumor tissue was obtained from eighty-three paraffin- embedded blocks which were using resected tissue from both the primary tumor and metastatic sites for each patient. We performed immunohistochemical staining for wnt3a, wnt5a, β-catenin, MMP-9 and VEGFR-2.

Results

Wnt3a, wnt5a, β-catenin, and MMP-9 expression was high; the proteins were found in over 50% of the primary tumors, but the prevalence was lower in tissue from metastatic sites. The concordance rates between the primary tumor and metastatic site were 76.2% for wnt5a and 79.4% for wnt3a and β-catenin, but VEGFR-2 was expressed in 67.4% of the metastatic sites even when not found in the primary tumor. Wnt3a expression in primary tumors was significantly associated with lymph node involvement (p = 0.038) and MMP-9 expression in the primary tumor (p = 0.0387), mesenchyme adjacent to tumor (p = 0.022) and metastatic site (p = 0.004). There was no other relationship in the expression of these proteins. Vascular invasion in primary tumor tissue may be a potential prognostic marker for liver metastasis, but no significant association was observed among the wnt protein, MMP-9, and VEGFR-2 for peritoneal seeding. In survival analysis, β-catenin expression was significantly correlated with overall survival (p = 0.05).

Conclusions

Wnt3a and wnt5a expression had a concordance rate higher than 60% with a high concordance rate between the primary tumor and metastatic site. Wnt3a expression is associated with the expression of MMP-9 in primary tumor tissue adjacent mesenchymal tissue, and at the metastatic site. As a prognostic marker, only β-catenin expression showed significant relation with survival outcome.

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

Nuclear LEF1/TCF4 correlate with poor prognosis but not with nuclear β-catenin in cerebral metastasis of lung adenocarcinomas

An essential function of the transcription factors LEF1/TCF4 in cerebral metastases of lung adenocarcinomas has been described in mouse models, suggesting a WNT/β-catenin effect as potential mechanism. Their role in humans is still unclear, thus we analyzed LEF1, TCF4, β-catenin, and early stage prognostic markers in 25 adenocarcinoma brain metastases using immunohistochemistry (IHC). IHC revealed nuclear TCF4 in all adenocarcinoma samples, whereas only 36 % depicted nuclear LEF1 and nuclear β-catenin signals. Samples with nuclear LEF1 as well as high TCF4 (++++) expression were associated with a shorter survival (p = 0.01, HR = 6.68), while nuclear β-catenin had no significant impact on prognosis and did not significantly correlate with nuclear LEF1. High proliferation index Ki67 was associated with shorter survival in late-stage disease (p = 0.03, HR 3.27). Additionally, we generated a LEF1/TCF4 as well as an AXIN2 signature, the latter as representative of WNT/β-catenin activity, following a bioinformatics approach with a gene expression dataset of cerebral metastases in lung adenocarcinoma. To analyze the prognostic relevance in primary lung adenocarcinomas, we applied both signatures to a microarray dataset of 58 primary lung adenocarcinomas. Only the LEF1/TCF4 signature was able to separate clusters with impact on survival (p = 0.01, HR = 0.32). These clusters displayed diverging enrichment patterns of the cell cycle pathway. In conclusion, our data show that LEF1/TCF4, but not β-catenin, have prognostic relevance in primary and cerebrally metastasized human lung adenocarcinomas. In contrast to the previous in vivo findings, these results indicate that LEF1/TCF4 act independently of β-catenin in this setting.

Targeting Wnt pathways in disease

Wnt-mediated signal transduction pathways have long been recognized for their roles in regulating embryonic development, and have more recently been linked to cancer, neurologic diseases, inflammatory diseases, and disorders of endocrine function and bone metabolism in adults. Although therapies targeting Wnt signaling are attractive in theory, in practice it has been difficult to obtain specific therapeutics because many components of Wnt signaling pathways are also involved in other cellular processes, thereby reducing the specificity of candidate therapeutics. New technologies, and advances in understanding the mechanisms of Wnt signaling, have improved our understanding of the nuances of Wnt signaling and are leading to promising new strategies to target Wnt signaling pathways.

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.

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

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

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.

Targeting the Wnt/β-catenin signaling pathway in human cancers

INTRODUCTION

The Wnt/β-catenin signaling pathway plays a pivotal role in the regulation of cell growth, cell development and the differentiation of normal stem cells. Constitutive activation of the Wnt/β-catenin signaling pathway is found in many human cancers, and is thus an attractive target for anti-cancer therapy. Specific inhibitors of this pathway have been keenly researched and developed.

AREAS COVERED

This review discusses the potential of inhibiting the Wnt/β-catenin signaling pathway, as a therapeutic approach for cancer, along with an overview of the development of specific inhibitors.

EXPERT OPINION

Cancer stem cells (CSCs) play a significant role in the development and recurrence of several cancers, and Wnt/β-catenin signaling is important for the proliferation of CSCs. Inhibition of Wnt/β-catenin signaling is therefore a promising treatment approach. Progress has been made in the development of screening methods to identify Wnt/β-catenin signaling inhibitors. Biomarker-based screening is an effective and promising method for the identification of compounds of interest.

β-catenin activation is associated with specific clinical and pathologic characteristics and a poor outcome in adrenocortical carcinoma

PURPOSE

Activation of the Wnt/β-catenin signaling pathway is frequent in adrenocortical carcinoma (ACC) and might be associated with a more aggressive phenotype. The objective of this study was to assess the prognostic value of β-catenin immunohistochemistry and CTNNB1 (β-catenin gene)/APC (adenomatous polyposis coli gene) mutations in patients with resected primary ACC.

EXPERIMENTAL DESIGN

In 79 patients with resected primary ACC from a French cohort (Cochin-COMETE), β-catenin expression was assessed on tumor specimens by immunohistochemistry. For patients with available DNA (n = 49), CTNNB1, and APC hotspot (mutation cluster region), were sequenced. Association between these results and the clinicopathologic characteristics of the ACC and overall and disease-free survival were studied. Results were confirmed on a tissue microarray from an independent multicentric cohort of 92 ACC from Germany (German-ENSAT cohort).

RESULTS

In the Cochin-COMETE cohort, the presence of a β-catenin nuclear staining was significantly associated with a higher ENSAT tumor stage (i.e., stages III and IV), higher Weiss score, more frequent necrosis, mitoses, and CTNNB1/APC mutations. β-Catenin nuclear staining and the presence of CTNNB1/APC mutations were both associated with decreased overall and disease-free survival, and were independent predictive factors of survival in multivariate analysis. The same results were observed in the German-ENSAT cohort.

CONCLUSIONS

Wnt/β-catenin activation, confirmed by the presence of β-catenin nuclear staining, is an independent prognostic factor of overall and disease-free survival in patients with resected primary ACC.

Prognostic relevance of β-catenin expression in T2-3N0M0 esophageal squamous cell carcinoma

AIM: To study the expression of β-catenin in esophageal squamous cell carcinoma (ESCC) at stage T2-3N0M0 and its relation with the prognosis of ESCC patients.

METHODS: Expression of β-catenin in 227 ESCC specimens was detected by immunohistochemistry (IHC). A reproducible semi-quantitative method which takes both staining percentage and intensity into account was applied in IHC scoring, and receiver operating characteristic curve analysis was used to select the cut-off score for high or low IHC reactivity. Then, correlation of β-catenin expression with clinicopathological features and prognosis of ESCC patients was determined.

RESULTS: No significant correlation was observed between β-catenin expression and clinicopathological parameters in terms of gender, age, tumor size, tumor grade, tumor location, depth of invasion and pathological stage. The Kaplan-Meier survival curve showed that the up-regulated expression of β-catenin indicated a poorer post-operative survival rate of ESCC patients at stage T2-3N0M0 (P = 0.004), especially of those with T3 lesions (P = 0.014) or with stage IIB diseases (P = 0.007). Multivariate analysis also confirmed that β-catenin was an independent prognostic factor for the overall survival rate of ESCC patients at stage T2-3N0M0 (relative risk = 1.642, 95% CI: 1.159-2.327, P = 0.005).

CONCLUSION: Elevated β-catenin expression level may be an adverse indicator for the prognosis of ESCC patients at stage T2-3N0M0, especially for those with T3 lesions or stage IIB diseases.

A re-evaluation of the "oncogenic" nature of Wnt/beta-catenin signaling in melanoma and other cancers

In cancer, Wnt/β-catenin signaling is ubiquitously referred to as an “oncogenic” pathway that promotes tumor progression. This review examines how the regulation and downstream effects of Wnt/β-catenin signaling in cancer varies depending on cellular context, with a focus on malignant melanoma. We emphasize that the cellular homeostasis of Wnt/β-catenin signaling may represent a more appropriate concept than the simplified view of the Wnt/β-catenin pathway as either oncogenic or tumor-suppressing. Ultimately, a more refined understanding of the contextual regulation of Wnt/β-catenin signaling will be essential for addressing if and how therapeutic targeting of this pathway could be leveraged for patient benefit.

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.

Immunohistochemical analyses of E-cadherin, beta-catenin, CD44s, and CD44v6 expressions, and Ki-67 labeling index in intraductal papillary mucinous neoplasms of the pancreas and associated invasive carcinomas

We examined the expressions of adhesion molecules (E-cadherin, beta-catenin, CD44s, and CD44v6) and Ki-67 labeling index (Ki-67 LI) in low- and moderate-grade dysplasia and invasive carcinoma components in ten noninvasive intraductal papillary mucinous neoplasms (IPMNs) of the pancreas and eight invasive carcinomas associated with IPMNs of the pancreas using immunohistochemical methods. There was no significant difference in regard to the proportion of components expressing either E-cadherin or beta-catenin in more than 70% of the tumor cells between the low- and moderate-grade dysplasia components. In contrast, the proportion of those in invasive carcinoma components was significantly lower than in low- or moderate-grade dysplasia components. Also, there was no significant difference in the proportion of components expressing CD44s or CD44v6 in more than 5% of tumor cells among low-grade dysplasia, moderate-grade dysplasia, and invasive carcinoma components. In contrast, the Ki-67 LI values increased in the order of low-grade dysplasia, moderate-grade dysplasia, and invasive carcinoma components, with significant differences among them. The present results indicate that carcinoma components are associated with a decrease in tumor cells expressing E-cadherin and beta-catenin and have the highest proliferative activity.

High expression of claudin-1 protein in papillary thyroid tumor and its regional lymph node metastasis

Claudins, known as major contributors in the formation of the tight junction, are differentially expressed in malignant tumors as compared to the corresponding healthy tissues. Therefore, they are thought to play a role in carcinogenesis and tumor progression. Altered expression of claudin-1 has been reported in several tumor types including endometrial, papillary renal cell and colonic carcinoma, and increased claudin-1 mRNA levels have been observed in papillary thyroid carcinoma (PTC). In this study, we aimed at determining the pattern of claudin-1 expression in various types of thyroid lesions at the protein level and investigating the immunolocalization of beta-catenin reported to regulate claudin-1 expression. Samples included 19 PTCs, ten cases of corresponding regional lymph node metastasis, eight papillary microcarcinomas (PMC), 17 follicular thyroid carcinomas (FTC) and 19 follicular adenomas (FA). All cases were evaluated by quantitative immunohistochemistry. Conspicuous claudin-1 immunostaining was detected in the majority of PTC/PMC primary tumors and lymph node metastases (19/27 and 9/10, respectively). On the other hand, we found weak or no claudin-1 expression in any of the FA and FTC cases or peritumoral non-malignant thyroid tissues. Our data prove that high claudin-1 protein expression is specific for PTC and its regional lymph node metastases, while we failed to verify that claudin-1 is regulated by beta-catenin in thyroid tumors. Based on these results, claudin-1 may be a useful tumor marker for PTC.

Expression of SFRP2 and β-catenin in the carcinogenesis and progression of colorectal carcinoma

AIM: To investigate the role of Secreted Frizzled-related proteins 2 (SFRP2) and β-catenin in carcinogenesis and progression of colorectal carcinoma.

METHODS: Expression of SFRP2 and β-catenin proteins were examined immunohistochemically in 20 cases of normal colorectal mucosa, 20 cases of colorectal polyp, 36 cases of colorectal adenomas and 42 cases of colorectal carcinoma. The corresponding clinical data between the expression of SFRP2 and β-catenin proteins were analyzed retrospectively.

RESULTS: The positive expression rates of SFRP2 were significantly lower in colorectal carcinoma and colorectal adenoma than in normal colorectal mucosa and colorectal polyp (28.57% vs 100.0%, 95.0%; 36.11% vs 100.0%, 95.0%, all P < 0.05). The reduced membranous β-catenin expression rate was significantly higher in colorectal carcinoma than in normal colorectal mucosa, colorectal polyp and colorectal adenoma (52.4% vs 0%, 0%, 11.1%, all P < 0.05). The cytoplasmic and nuclear β-catenin expression rates were significantly higher in colorectal carcinoma and colorectal adenomas than in normal colorectal mucosa and colorectal polyp (64.3% vs 0%, 0%; 30.6% vs 0%, 0%, all P < 0.05), higher in colorectal carcinoma than in colorectal adenomas (P < 0.05). The positive expression of SFRP2, reduced membranous β-catenin expression and cytoplasmic and nuclear β-catenin expression in colorectal carcinoma were significantly correlated with the tumor differentiation, but not with the tumor position, morphology or size, lymph node metastasis or Duke's stage. Besides, the positive expression of SFRP2 was significantly correlated with the depth of invasion in colorectal carcinoma. The positive expression of SFRP2 was negatively correlated with the reduced membranous β-catenin expression (r = -0.452, P = 0.003) and cytoplasmic and nuclear β-catenin expression (r = -0.519, P = 0.000). There existed positive correlation between the reduced membranous β-catenin expression and cytoplasmic and nuclear β-catenin expression (r = 0.782, P = 0.000).

CONCLUSION: The expression of SFRP2 and β-catenin are closely correlated with the carcinogenesis and progression of colorectal carcinoma, and may be an early event. The positive expression of SFRP2 is negatively correlated with the reduced membranous β-catenin expression and cytoplasmic and nuclear β-catenin expression. The former may inhibit carcinogenesis and latter may promote carcinogenesis.