Differential Wnt pathway gene expression and E-cadherin truncation in sporadic colorectal cancers with and without microsatellite instability

T cell-inflamed gene expression profile is associated with favorable disease-specific survival in non-hypermutated microsatellite-stable colorectal cancer patients

BACKGROUND

The anti-tumor immune response plays a key role in colorectal cancer (CRC) progression and survival. The T cell-inflamed gene expression profile (GEP) is a biomarker predicting response to checkpoint inhibitor immunotherapy across immunogenic cancer types, but the prognostic value in CRC is unknown. We evaluated associations with disease-specific survival, somatic mutations, and examined its differentially expressed genes and pathways among 84 sporadic CRC patients from the Seattle Colon Cancer Family Registry.

METHODS

Gene expression profiling was performed using Nanostring's nCounter PanCancer IO 360 panel. Somatic mutations were identified by a targeted DNA sequencing panel.

RESULTS

The T cell-inflamed GEP was positively associated with tumor mutation burden and microsatellite instability high (MSI-H). Higher T cell-inflamed GEP had favorable CRC-specific survival (hazard ratio [HR] per standard deviation unit = 0.50, p = 0.004) regardless of hypermutation or MSI status. Analysis of recurrently mutated genes having at least 10 mutation carriers, suggested that the T cell-inflamed GEP is positively associated with RYR1, and negatively associated with APC. However, these associations were attenuated after adjusting for hypermutation or MSI status. We also found that expression of genes RPL23, EPCAM, AREG and ITGA6, and the Wnt signaling pathway was negatively associated with the T cell-inflamed GEP, which might indicate immune-inhibitory mechanisms.

CONCLUSIONS

Our results show that the T cell-inflamed GEP is a prognostic biomarker in non-hypermutated microsatellite-stable CRC. This also suggests that patient stratification for immunotherapy within this CRC subgroup should be explored further. Moreover, reported immune-inhibitory gene expression signals may suggest targets for therapeutic combination with immunotherapy.

LIN28 promotes tumorigenesis in colorectal cancer but is not associated with metastatic spread

BACKGROUND

Tumor stem cells play a role in metastatic spread in colorectal cancer (CRC). The oncogene LIN28A/B, a prognostic marker in CRC, is involved in tumorigenesis and maintains stem cell function. Therefore, it was the aim of the present study to clarify whether LIN28A/B is involved in metastatic spread in CRC.

METHODS

Expression of LIN28A/B was analyzed in patients with colon adenocarcinoma in a matched case-control study comparing patients with corresponding liver metastases (n = 42) and patients without hepatic spread within five years (n = 42) by applying immunohistochemistry. Further, LIN28A/B expression was correlated with stem cell associated markers (SOX2, CD133).

RESULTS

LIN28A and B expression significantly correlated with SOX2 expression (p = .02, and p = .04 respectively) but not with CD133 expression. This correlation between LIN28 A/B and SOX2 was not reflected in differences in hepatic spread. In this respect, there was no significant association between LIN28A/B expression and liver metastases.

CONCLUSION

LIN28A/B might be involved in tumor initiation and progression in CRC but is not associated with hepatic spread.

Role of FUT8 expression in clinicopathology and patient survival for various malignant tumor types: a systematic review and meta-analysis

Dysregulation of α(1,6)-fucosyltransferase (FUT8) plays significant roles in development of a variety of malignant tumor types. We collected as many relevant articles and microarray datasets as possible to assess the prognostic value of FUT8 expression in malignant tumors. For this purpose, we systematically searched PubMed, Embase, Web of Science, Springer, Chinese National Knowledge Infrastructure (CNKI), and Wan Fang, and eventually identified 7 articles and 35 microarray datasets (involving 6124 patients and 10 tumor types) for inclusion in meta-analysis. In each tumor type, FUT8 expression showed significant (p< 0.05) correlation with one or more clinicopathological parameters; these included patient gender, molecular subgroup, histological grade, TNM stage, estrogen receptor, progesterone receptor, and recurrence status. In regard to survival prognosis, FUT8 expression level was associated with overall survival in non-small cell lung cancer (NSCLC), breast cancer, diffuse large B cell lymphoma, gastric cancer, and glioma. FUT8 expression was also correlated with disease-free survival in NSCLC, breast cancer, and colorectal cancer, and with relapse-free survival in pancreatic ductal adenocarcinoma. For most tumor types, survival prognosis of patients with high FUT8 expression was related primarily to clinical features such as gender, tumor stage, age, and pathological category. Our systematic review and meta-analysis confirmed the association of FUT8 with clinicopathological features and patient survival rates for numerous malignant tumor types. Verification of prognostic value of FUT8 in these tumor types will require a large-scale study using standardized methods of detection and analysis.

Metadherin-PRMT5 complex enhances the metastasis of hepatocellular carcinoma through the WNT-β-catenin signaling pathway

Accumulating data suggest that metadherin (MTDH) may function as an oncogene. Our previous study showed that MTDH promotes hepatocellular carcinoma (HCC) metastasis via the epithelial-mesenchymal transition. In this study, we aim to further elucidate how MTDH promotes HCC metastasis. Using Co-immunoprecipitation (co-IP) and mass spectrometry, we found that MTDH can specifically bind to protein arginine methyltransferase 5 (PRMT5). Further functional assays revealed that PRMT5 overexpression promoted the proliferation and motility of HCC cells and that knockout of PRMT5 impeded the effect of MTDH. The immunohistochemistry assay/tissue microarray results showed that when MTDH was overexpressed in HCC cells, PRMT5 translocated from the nucleus to the cytoplasm, with the subsequent translocation of β-catenin from the cytoplasm to the nucleus and upregulation of the WNT-β-catenin signaling pathway. Further in vivo experiments suggested that PRMT5 and β-catenin played a pivotal role in MTDH-mediated HCC metastasis. We therefore concluded that the MTDH-PRMT5 complex promotes HCC metastasis by regulating the WNT-β-catenin signaling pathway.

Characterization of canonical Wnt signalling changes after induced disruption of Müller cell in murine retina

Müller cells are the primary glia in the retina, playing a critical role in retinal homeostasis and retinal pathology. This study evaluated the canonical Wnt signalling pathway and its downstream effects on retinal degeneration in a transgenic mouse model of inducible Müller cell disruption. Increased expression of the LacZ reporter gene in the retina suggested Wnt signalling had been activated after induced Müller cell disruption. Activation was validated by observing nuclear translocation of β-Catenin. The mRNA expression of 80 Wnt related genes were assessed using real-time PCR. The Wnt signalling inhibitors Dkk1, Dkk3 and sFRP3 were significantly downregulated. Furthermore, the ubiquitin-mediated β-Catenin proteolysis genes β-TrCP and SHFM3, were also significantly downregulated. The downstream target genes of the Wnt signalling, including Fra1, CyclinD2 and C-Myc were upregulated. The changes of these genes at the protein level were validated by Western blot. Their distributions in the retina were evaluated by immunofluorescent staining. Our findings indicate that Müller cells are involved in retinal Wnt signalling. Activation of Wnt signalling and its downstream target genes may play important roles in photoreceptor degeneration and neovascularization occurring in the retina after induced disruption of Müller cells.

Down-regulating cyclin-dependent kinase 9 of alloreactive CD4+ T cells prolongs allograft survival

CDK9 (Cyclin-dependent kinase 9)/Cyclin T1/RNA polymerase II pathway has been demonstrated to promote the development of several inflammatory diseases, such as arthritis or atherosclerosis, however, its roles in allotransplantation rejection have not been addressed. Here, we found that CDK9/Cyclin T1 were apparently up-regulated in the allogeneic group, which was positively correlated with allograft damage. CDK9 was inhibited obviously in naive splenic CD4⁺ T cells treated 6 h with 3 μM PHA767491 (a CDK9 inhibitor), and adoptive transfer of these CD4⁺ T cells into allografted SCID mice resulted in prolonged survival compared with the group without PHA767491 pretreated. Decelerated rejection was correlated with enhanced IL-4 and IL-10 production and with decreased IFN-γ production by alloreactive T cells. More interestingly, we found that CDK9₄₂, not CDK9₅₅, was high expressed in allorejection group, which could be prominently dampened with PHA767491 treatment. The expression of CDK9₄₂ was consistent with its downstream molecule RNA polymerase II. Altogether, our findings revealed the crucial role of CDK9/Cyclin T1/Pol II pathway in promoting allorejection at multiple levels and may provide a new approach for transplantation tolerance induction through targeting CDK9.

Cancer risk and overall survival in mismatch repair proficient hereditary non-polyposis colorectal cancer, Lynch syndrome and sporadic colorectal cancer

Mismatch repair proficient hereditary non-polyposis colorectal cancer (MSS-HNPCC) encloses a heterogeneous group of families consisting of different unknown genetic syndromes and/or aggregations cases. The lack of information about the hereditability of cancer risk in these families makes it difficult to carry out an individualized Genetic Counseling. Therefore, deep description of such families becomes important for a better classification and search for underlying susceptibility causes. The aim of this study is to describe and compare the clinical, morphological features, tumor KRAS status and overall survival in MSS-HNPCC, Lynch and sporadic colorectal cancer. A total of 37 MSS-HNPCC families, 50 Lynch families and 612 sporadic CRC were included. Clinical and morphological data were evaluated by reviewing medical and pathology reports of 55, 69 and 102 tumors respectively. KRAS/BRAF status were detected by allele specific real-time PCR. Standardized incidence ratios (SIR) were calculated among 602 MSS-HNPCC relatives and 668 Lynch relatives. Main features distinguishing MSS-HNPCC were diagnosis age (55.1 ± 12.6), preferential distal location (76%), polyp detection (45%) and familial colorectal cancer incidence (SIR = 6.6). In addition, we found increased incidences rates for kidney, stomach and uterus tumors. KRAS mutation rates were similar in the study populations (48.8 ± 5.8) but higher than those described before by Sanger sequencing. MSS-HNPCC overall survival was similar to Lynch in B Dukes' stage tumors and between Lynch and sporadic in C stage tumors. Anatomical and morphological data of MSS-HNPCC are consistent with other described populations. Our studies disclose an increased HNPCC-extracolonic tumors incidence and improved overall survival in MSS-HNPCC families.

Molecular patterns in the evolution of serrated lesion of the colorectum

Colorectal cancer (CRC) mostly develops from a variety of polyps following mainly three different molecular pathways: chromosomal instability (CIN), microsatellite instability (MSI) and CpG island methylation (CIMP). Polyps are classified histologically as conventional adenomas, hyperplastic polyps, sessile serrated adenomas/polyps (SSA/P) and traditional serrated adenomas (TSA). However, the association of these polyps with the different types of CRCs and the underlying genetic and epigenetic aberrations has yet to be resolved. In order to address this question we analyzed 140 tumors and 20 matched mucosae by array comparative genomic hybridization, by sequence analysis of the oncogenes BRAF, KRAS, PI3K3CA and by methylation arrays. MSI was tested indirectly by immunohistochemistry (IHC) and a loss of MLH1, MSH2, MSH6 or PMS2 was assigned as high microsatellite instability (MSI-H), while low microsatellite instability (MSI-L) was defined as MGMT IHC negativity only. CIN was detected in 78% of all MSI-H CRCs, most commonly as a gain of chromosome 8. Methylation data analyses allowed classification of samples into four groups and detected similar methylation profiles in SSA/P and MSI-H CRC. TSA also revealed aberrant methylation pattern, but clustered more heterogeneously and closer to microsatellite stable (MSS) CRCs. SSA/P, TSA and MSI-H CRCs had the highest degree of promotor methylation (CIMP pathway). Chromosomal instability, in contrast to the established doctrine, is a common phenomenon in MSI CRCs, yet to a lower extent and at later stages than in MSS CRCs. Methylation analyses suggest that SSA/P are precursors for MSI-H CRCs and follow the CIMP pathway.

Genetic and epigenetic events generate multiple pathways in colorectal cancer progression

Colorectal cancer (CRC) is one of the most common causes of death, despite decades of research. Initially considered as a disease due to genetic mutations, it is now viewed as a complex malignancy because of the involvement of epigenetic abnormalities. A functional equivalence between genetic and epigenetic mechanisms has been suggested in CRC initiation and progression. A hallmark of CRC is its pathogenetic heterogeneity attained through at least three distinct pathways: a traditional (adenoma-carcinoma sequence), an alternative, and more recently the so-called serrated pathway. While the alternative pathway is more heterogeneous and less characterized, the traditional and serrated pathways appear to be more homogeneous and clearly distinct. One unsolved question in colon cancer biology concerns the cells of origin and from which crypt compartment the different pathways originate. Based on molecular and pathological evidences, we propose that the traditional and serrated pathways originate from different crypt compartments explaining their genetic/epigenetic and clinicopathological differences. In this paper, we will discuss the current knowledge of CRC pathogenesis and, specifically, summarize the role of genetic/epigenetic changes in the origin and progression of the multiple CRC pathways. Elucidation of the link between the molecular and clinico-pathological aspects of CRC would improve our understanding of its etiology and impact both prevention and treatment.

Colon cancer molecular subtypes identified by expression profiling and associated to stroma, mucinous type and different clinical behavior

Background

Colon cancer patients with the same stage show diverse clinical behavior due to tumor heterogeneity. We aimed to discover distinct classes of tumors based on microarray expression patterns, to analyze whether the molecular classification correlated with the histopathological stages or other clinical parameters and to study differences in the survival.

Methods

Hierarchical clustering was performed for class discovery in 88 colon tumors (stages I to IV). Pathways analysis and correlations between clinical parameters and our classification were analyzed. Tumor subtypes were validated using an external set of 78 patients. A 167 gene signature associated to the main subtype was generated using the 3-Nearest-Neighbor method. Coincidences with other prognostic predictors were assesed.

Results

Hierarchical clustering identified four robust tumor subtypes with biologically and clinically distinct behavior. Stromal components (p < 0.001), nuclear β-catenin (p = 0.021), mucinous histology (p = 0.001), microsatellite-instability (p = 0.039) and BRAF mutations (p < 0.001) were associated to this classification but it was independent of Dukes stages (p = 0.646). Molecular subtypes were established from stage I. High-stroma-subtype showed increased levels of genes and altered pathways distinctive of tumour-associated-stroma and components of the extracellular matrix in contrast to Low-stroma-subtype. Mucinous-subtype was reflected by the increased expression of trefoil factors and mucins as well as by a higher proportion of MSI and BRAF mutations. Tumor subtypes were validated using an external set of 78 patients. A 167 gene signature associated to the Low-stroma-subtype distinguished low risk patients from high risk patients in the external cohort (Dukes B and C:HR = 8.56(2.53-29.01); Dukes B,C and D:HR = 1.87(1.07-3.25)). Eight different reported survival gene signatures segregated our tumors into two groups the Low-stroma-subtype and the other tumor subtypes.

Conclusions

We have identified novel molecular subtypes in colon cancer with distinct biological and clinical behavior that are established from the initiation of the tumor. Tumor microenvironment is important for the classification and for the malignant power of the tumor. Differential gene sets and biological pathways characterize each tumor subtype reflecting underlying mechanisms of carcinogenesis that may be used for the selection of targeted therapeutic procedures. This classification may contribute to an improvement in the management of the patients with CRC and to a more comprehensive prognosis.

Loss of E-cadherin promotes the growth, invasion and drug resistance of colorectal cancer cells and is associated with liver metastasis

The recent studies indicated that the epithelial cell adhesion molecule E-cadherin is a well-recognized molecule that is important in cell adhesion. To further investigate the molecular basis of this notion, we used small-interfering RNA to inhibit E-cadherin function and found that loss of E-cadherin promoted Colorectal cancer cell growth, invasion and drug resistance through induction of β-catenin nuclear translocation and epithelial-to-mesenchymal transition. Further analysis of E-cadherin expression with clinicopathologic parameters showed that E-cadherin expression decreased in Colorectal cancer patients who developed liver metastasis (P = 0.043). These findings indicate that E-cadherin loss in tumors contributes to progression and metastatic dissemination. Thus, E-cadherin can act as a central modulator of the cell biological phenotypes and a potential prognostic marker in Colorectal cancer.

Metadherin promotes hepatocellular carcinoma metastasis through induction of epithelial-mesenchymal transition

PURPOSE

To investigate the expression of metadherin (MTDH) for its prognostic value in hepatocellular carcinoma (HCC) and its role in promoting HCC metastasis.

EXPERIMENTAL DESIGN

This study employed a tissue microarray containing samples from 323 HCC patients to examine the expression of MTDH and its correlation with other clinicopathologic characteristics. The role of MTDH in the regulation of HCC metastasis was investigated both in vitro and in vivo using short hairpin RNA (shRNA)-mediated downregulation of MTDH in HCC cell lines with various metastatic potentials.

RESULTS

The expression of MTDH was markedly higher in HCC tumors than in normal liver tissue. Particularly high MTDH expression was observed in tumors with microvascular invasion, pathologic satellites, poor differentiation, or tumor-node-metastasis stages II to III. Furthermore, the clinical outcome was consistently poorer for the MTDH(high) group than for the MTDH(low) group in the 1-, 3-, and 5-year overall survival (OS) rates and in the 1-, 3-, 5-year cumulative recurrence rates. In a nude mice model, the shRNA-mediated downregulation of MTDH resulted in a reduced migratory capacity in HCC cell lines, as well as a reduction in pulmonary and abdominal metastasis. Furthermore, we found that the expression level of MTDH correlated with four epithelial-mesenchymal transition (EMT) markers. Knockdown of MTDH expression in HCC cell lines resulted in downregulation of N-cadherin and snail, upregulation of E-cadherin, and translocation of β-catenin.

CONCLUSIONS

MTDH may promote HCC metastasis through the induction of EMT process and may be a candidate biomarker for prognosis as well as a target for therapy.

Epithelial-mesenchymal transition (EMT) protein expression in a cohort of stage II colorectal cancer patients with characterized tumor budding and mismatch repair protein status

INTRODUCTION

The relationship between tumor budding, epithelial-mesenchymal transition (EMT) protein expression, and survival has not been closely examined in stage II colorectal cancer (CRC). This study aimed to assess proteins implicated in EMT and to correlate their expression with tumor budding, microsatellite status, and survival.

METHODS

A total of 258 stage II CRCs were identified (tumor budding characterized in 122 cases). Immunohistochemistry for LAMC2, E cadherin, cathepsin L, and β catenin using tissue microarrays was performed. EMT and mismatch repair (MMR) protein expression were correlated with tumor budding and survival.

RESULTS

LAMC2 positivity (P < .001) and low membranous β catenin (P = .056) were associated with tumor budding. In a univariate survival analysis, tumor budding (P < .001), LAMC2 positivity (P < .03), and stromal cytoplasmic cathepsin L (P = .025) predicted poorer prognosis. Multivariate analysis showed tumor budding to be the only variable independently associated with survival: hazard ratio = 7.9 (95% confidence interval = 3-21); P < .001. Tumor budding was more frequent in microsatellite-stable (MSS) versus microsatellite-instable (MSI) tumors: 48% versus 26%, respectively; P = .087. MSS cases exhibited reduced membranous β catenin (P = .002) and increased cytoplasmic and nuclear β catenin (P < .001) compared with MSI cases.

CONCLUSION

Epithelial mesenchymal protein expression plays a key role in tumor budding and prognosis in early-stage colorectal cancer and requires further evaluation.

Promoter methylation of Wnt5a is associated with microsatellite instability and BRAF V600E mutation in two large populations of colorectal cancer patients

Background:

In colorectal cancer (CRC), tumour microsatellite instability (MSI) status and CpG island methylator phenotype (CIMP) status are indicators of patient outcome, but the molecular events that give rise to these outcomes remain largely unknown. Wnt5a is a critical regulator of non-canonical Wnt activity and promoter hypermethylation of this gene has emerging prognostic roles in CRC; however the frequency and prognostic significance of this epigenetic event have not been explored in the context of colorectal tumour subtype. Consequently, we investigated the frequency and prognostic significance of Wnt5a methylation in a large cohort of MSI-stratified CRCs.

Methods:

Methylation was quantified in a large cohort of 1232 colorectal carcinomas from two clinically distinct populations from Canada. Associations were examined between methylation status and clinicopathlogical features, including tumour MSI status, BRAF V600E mutation, and patient survival.

Results:

In Ontario, Wnt5a methylation was strongly associated with MSI tumours after adjustment for age, sex, and tumour location (odds ratio (OR)=4.2, 95% confidence interval (CI)=2.4–7.4, P<10⁻⁶) and with BRAF V600E mutation, a marker of CIMP (OR=12.3, 95% CI=6.9–21.7, P<10⁻¹⁷), but was not associated with patient survival. Concordant results were obtained in Newfoundland.

Conclusion:

Methylation of Wnt5a is associated with distinct tumour subtypes, strengthening the evidence of an epigenetic-mediated Wnt bias in CRC.

Alternatively Expressed Genes Identified in the CD4+ T Cells of Allograft Rejection Mice

Allograft rejection is a leading cause for the failure of allotransplantation. CD4+ T cells play critical roles in this process. The identification of genes that alternatively expressed in CD4+ T cells during allograft rejection will provide critical information for studying the mechanism of allograft rejection, finding specific gene markers for monitoring, predicting allograft rejection, and opening new ways to regulate and prevent allograft rejection. Here, we established allograft and isograft transplantation models by adoptively transferring wild-type BALB/c mouse CD4+ T cells into severe combined immunodeficient (SCID) mice with a C57BL/6 or BALB/c mouse skin graft. Using the whole transcriptome sequencing-based serial analysis of gene expression (SAGE) technology, we identified 97 increasingly and 88 decreasingly expressed genes that may play important roles in allograft rejection and tolerance. Functional classification of these genes shows that apoptosis, transcription regulation, cell growth and maintenance, and signal transduction are among the frequently changed functional groups. This study provides a genome-wide view for the candidate genes of CD4+ T cells related to allotransplantation, and this report is a good resource for further microarray studies and for identifying the specific markers that are associated with clinical organ transplantations.

Promoter methylation of Wnt antagonists DKK1 and SFRP1 is associated with opposing tumor subtypes in two large populations of colorectal cancer patients

Aberrant activation of canonical Wnt signaling is a hallmark event in colorectal carcinogenesis. The Dickkopf-1 (DKK1) and Secreted Frizzled Related Protein 1 (SFRP1) genes encode extracellular inhibitors of Wnt signaling that are frequently silenced by promoter hypermethylation in colorectal cancer (CRC). These methylation events have been identified as prognostic markers of patient outcome and tumor subtype in several cancers but similar roles in CRC have not been comprehensively examined. In CRC, the microsatellite instability (MSI) subtype associates with favorable disease outcome but the molecular events that are responsible remain poorly understood. Consequently, we quantified promoter methylation status of the Wnt antagonist genes DKK1 and SFRP1 in a large population-based cohort of CRCs from Ontario (n = 549) and Newfoundland (n = 696) stratified by MSI status. We examined the association between methylation status and clinicopathological features including tumor MSI status and patient survival. DKK1 and SFRP1 were methylated in 13 and 95% of CRCs, respectively. In Ontario, DKK1 methylation was strongly associated with MSI tumors after adjustment for age, sex and tumor location [odds ratio (OR) = 13.7, 95% confidence interval (CI) = 7.8-24.2, P < 0.001]. Conversely, SFRP1 methylation was inversely associated with MSI tumors after these adjustments (OR = 0.3, 95% CI = 0.1-0.9, P = 0.009). Similar results were obtained in Newfoundland. There were no independent associations with recurrence-free survival. This is the first large study to identify associations between Wnt antagonist promoter hypermethylation and CRC MSI subtype. These events provide insight into subtype-specific epigenetic mediation of Wnt signaling in CRC.

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.

Relationship of CDX2 loss with molecular features and prognosis in colorectal cancer

PURPOSE

The homeodomain transcription factor CDX2 is a relatively specific immunohistochemical marker for gastrointestinal carcinoma. However, no study has comprehensively examined the relationship between CDX2 expression in colon cancer and clinical, pathologic, prognostic, and molecular features, including microsatellite instability and CpG island methylator phenotype (CIMP).

EXPERIMENTAL DESIGN

Utilizing 621 colorectal cancers with clinical outcome and molecular data, CDX2 loss was detected in 183 (29%) tumors by immunohistochemistry.

RESULTS

In multivariate logistic regression analysis, CDX2 loss was associated with female gender [odds ratio (OR), 3.32; P < 0.0001], CIMP-high (OR, 4.42; P = 0.0003), high tumor grade (OR, 2.69; P = 0.0085), stage IV disease (OR, 2.03; P = 0.019), and inversely with LINE-1 hypomethylation (for a 30% decline; OR, 0.33; P = 0.0031), p53 expression (OR, 0.55; P = 0.011), and beta-catenin activation (OR, 0.60; P = 0.037), but not with body mass index, tumor location, microsatellite instability, BRAF, KRAS, PIK3CA, p21, or cyclooxygenase-2. CDX2 loss was not independently associated with patient survival. However, the prognostic effect of CDX2 loss seemed to differ according to family history of colorectal cancer (P(interaction) = 0.0094). CDX2 loss was associated with high overall mortality (multivariate hazard ratio, 2.40; 95% CI, 1.28-4.51) among patients with a family history of colorectal cancer; no such association was present (multivariate hazard ratio, 0.97; 95% CI, 0.66-1.41) among patients without a family history of colorectal cancer.

CONCLUSIONS

CDX2 loss in colorectal cancer is independently associated with female gender, CIMP-high, high-level LINE-1 methylation, high tumor grade, and advanced stage. CDX2 loss may be associated with poor prognosis among patients with a family history of colorectal cancer.

Relationship of CDX2 loss with molecular features and prognosis in colorectal cancer

PURPOSE

The homeodomain transcription factor CDX2 is a relatively specific immunohistochemical marker for gastrointestinal carcinoma. However, no study has comprehensively examined the relationship between CDX2 expression in colon cancer and clinical, pathologic, prognostic, and molecular features, including microsatellite instability and CpG island methylator phenotype (CIMP).

EXPERIMENTAL DESIGN

Utilizing 621 colorectal cancers with clinical outcome and molecular data, CDX2 loss was detected in 183 (29%) tumors by immunohistochemistry.

RESULTS

In multivariate logistic regression analysis, CDX2 loss was associated with female gender [odds ratio (OR), 3.32; P < 0.0001], CIMP-high (OR, 4.42; P = 0.0003), high tumor grade (OR, 2.69; P = 0.0085), stage IV disease (OR, 2.03; P = 0.019), and inversely with LINE-1 hypomethylation (for a 30% decline; OR, 0.33; P = 0.0031), p53 expression (OR, 0.55; P = 0.011), and beta-catenin activation (OR, 0.60; P = 0.037), but not with body mass index, tumor location, microsatellite instability, BRAF, KRAS, PIK3CA, p21, or cyclooxygenase-2. CDX2 loss was not independently associated with patient survival. However, the prognostic effect of CDX2 loss seemed to differ according to family history of colorectal cancer (P(interaction) = 0.0094). CDX2 loss was associated with high overall mortality (multivariate hazard ratio, 2.40; 95% CI, 1.28-4.51) among patients with a family history of colorectal cancer; no such association was present (multivariate hazard ratio, 0.97; 95% CI, 0.66-1.41) among patients without a family history of colorectal cancer.

CONCLUSIONS

CDX2 loss in colorectal cancer is independently associated with female gender, CIMP-high, high-level LINE-1 methylation, high tumor grade, and advanced stage. CDX2 loss may be associated with poor prognosis among patients with a family history of colorectal cancer.

Wnt-1 protein as a prognostic biomarker for hepatitis B-related and hepatitis C-related hepatocellular carcinoma after surgery

BACKGROUND

Up-regulation of Wnt-1 protein has been reported in hepatitis B virus (HBV)-related and hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC) tissues and cell lines. It is known to play a fundamental role in signaling cancer progression, whereas its prognostic role in HCC remains unexplored.

METHODS

As a prognostic biomarker, this study analyzed Wnt-1 protein expression in 63 histology-verified HCC patients receiving curative resection. In each paired tumor and nontumor specimen, Wnt-1 levels were semiquantitatively measured by Western blotting and expressed by tumor/nontumor ratio. The data were further correlated with quantitative real-time PCR as well as with beta-catenin and E-cadherin expression by immunohistochemistry. Cumulative tumor recurrence-free survival curves were constructed using the Kaplan-Meier method and compared by the log-rank test.

RESULTS

The results showed that 26 (group I) and 37 (group II) HCC patients had an expression ratio of Wnt-1 > or =1.5 and <1.5, respectively. The amount of Wnt-1 estimated by tumor/nontumor ratio correlated with the results by quantitative real-time PCR. High tumor Wnt-1 expression correlated with enhanced nuclear beta-catenin accumulation, diminished membranous E-cadherin expression, and increased tumor recurrence after curative tumor resection.

CONCLUSIONS

These results suggest that Wnt-1 may be used as a predisposing risk factor for HCC recurrence. The use of tumor Wnt-1 as prognostic biomarker may identify patients with HBV- and/or HCV-related HCC patients with a high risk of tumor recurrence who may then benefit from further intensive therapy after surgery.

Targeted endoscopic imaging

Endoscopy has undergone explosive technological growth in recent years, and with the emergence of targeted imaging, its truly transformative power and impact on medicine lies just over the horizon. Today, our ability to see inside the digestive tract with medical endoscopy is headed toward exciting crossroads. The existing paradigm of making diagnostic decisions based on observing structural changes and identifying anatomic landmarks may soon be replaced by visualizing functional properties and imaging molecular expression. In this novel approach, the presence of intracellular and cell surface targets unique to disease are identified and used to predict the likelihood of mucosal transformation and response to therapy. This strategy could result in the development of new methods for early cancer detection, personalized therapy, and chemoprevention. This targeted approach will require further development of molecular probes and endoscopic instruments, and will need support from the US Food and Drug Administration for streamlined regulatory oversight. Overall, this molecular imaging modality promises to significantly broaden the capabilities of the gastroenterologist by providing a new approach to visualize the mucosa of the digestive tract in a manner that has never been seen before.

TNF-induced activation of pulmonary microvessel endothelial cells: a role for GSK3beta

The hypothesis tested was PKCalpha mediates the phosphorylation of glycogen synthetase kinase 3beta (GSK3beta) and that the GSK3beta inhibition modulates the response to tumor necrosis factor-alpha (TNF) in rat pulmonary microvessel endothelial cells (PMEC). PMEC were treated with TNF for 4.0 h (100 ng/ml) or vehicle. First, to assess the role of PKCalpha in the phosphorylation of GSK3beta (i.e., an indicator of GSK3beta inhibition), PMEC were pretreated with 1) nonsense-RNA-PKCalpha, 2) siRNA-PKCalpha, and 3) the PKC inhibitor Gö6983. In the nonsense RNA-PKCalpha+TNF and TNF groups, there was increased phosphorylated GSK3beta-Ser9 that did not occur in the Gö6983+TNF group. In the TNF groups, there was a significant correlation between PKCalpha protein and phosphorylated GSK3beta-Ser9 that did not occur in the groups without TNF. Second, to assess the role of GSK3beta in beta-catenin activity, PMEC were pretreated with 1) wild-type (w) GSK3beta plasmid to enhance GSK3beta activity, 2) kinase dead (kd)-GSK3beta plasmid, and 3) the GSK3beta inhibitor SB-216763. In the TNF group, there was increased unphosphorylated beta-catenin-Ser37/33 compared with the control group. In the GSK3beta-inhibited groups (i.e., SB-216763 and kdGSK3beta) +/- TNF, the unphosphorylated beta-catenin-Ser37/33 was similar to the TNF group. In the GSK3beta-enhanced group +/- TNF, the unphosphorylated beta-catenin-Ser37/33 was similar to the control. Finally, PMEC were also treated with TOPflash, a beta-catenin-dependent promoter luciferase reporter, or the mutant construct FOPflash, 2 days before treatment with TNF. In the TNF group, there was an increased TOPflash/FOPflash activity ratio compared with the control group. In the GSK3beta-inhibited groups (i.e., SB-216763 and kdGSK3beta) +/- TNF, the TOPflash/FOPflash activity ratio was similar to the TNF group. In the GSK3beta-enhanced group +/- TNF, the TOPflash/FOPflash activity ratio was similar to the control. The data indicate that TNF induces endothelial activation that is modulated by a PKCalpha-dependent inhibition of GSK3beta.

Cyclin D1 is frequently overexpressed in microsatellite unstable colorectal cancer, independent of CpG island methylator phenotype

AIMS

Cyclin D1 and cyclin-dependent kinases are commonly activated in colorectal cancer. Microsatellite instability (MSI) and CpG island methylator phenotype (CIMP) are important molecular classifiers in colorectal cancer. The aim was to clarify the relationship between cyclin D1, MSI and CIMP.

METHODS AND RESULTS

Among 865 colorectal cancers with MSI and CIMP data, 246 tumours (28.4%) showed cyclin D1 overexpression by immunohistochemistry. DNA methylation in p14 and eight CIMP-specific promoters (CACNA1G, CDKN2A (p16), CRABP1, IGF2, MLH1, NEUROG1, RUNX3 and SOCS1) was quantified by real-time polymerase chain reaction (MethyLight). Both MSI-high and CIMP-high were associated with cyclin D1 overexpression (P < 0.0001). After tumours were stratified by MSI and CIMP status, the relationship between MSI-high and cyclin D1 persisted (P < or = 0.02), whereas the relationship between CIMP-high and cyclin D1 did not. Cyclin D1 overexpression was correlated with BRAF mutation (P = 0.0001), p27 loss (P = 0.0007) and p16 loss (P = 0.02), and inversely with p53 expression (P = 0.0002) and p21 loss (P < 0.0001). After stratification by MSI status, the inverse relationship between cyclin D1 and p21 loss still persisted (P < 0.008).

CONCLUSIONS

Cyclin D1 activation is associated with MSI and inversely with p21 loss in colorectal cancers. Cyclin D1 may play an important role in the development of MSI-high tumours, independent of CIMP status.

Ribonucleotide reductase small subunit p53R2 promotes oral cancer invasion via the E-cadherin/beta-catenin pathway

The p53-inducible p53R2 gene has been isolated and shown to play a crucial role in DNA repair and synthesis after DNA damage. Moreover, the expression and activity of p53R2 has been reported to be associated with the anticancer agent resistance of human cancer cells. Previously, we reported that the presence of p53R2 expression was a predictive factor for regional lymph node metastasis in oral squamous cell carcinoma; however, the mechanism of cancer metastasis by p53R2 expression is still unclear. In the present study, we analyzed the correlation of p53R2 expression with cancer invasion in vitro. Three human oral cancer cell lines (SAS, HSC-3 and Ca9-22) were cultured, and the invasive potential of these cancer cells was evaluated using Matrigel invasion assay. To investigate the effect of p53R2 on cancer invasion, the down-regulation of p53R2 was examined by small interfering RNA (siRNA). Moreover, we examined the intracellular localization of cell adhesion molecules (E-cadherin and beta-catenin) in subcellular extractions of cancer cells by immunoblotting. The proteolytic activity of matrix metalloproteinases (MMPs) was assessed by gelatin zymography. Down-regulation of p53R2 significantly enhanced the invasion potential (p<0.01), and enhanced nuclear translocation of beta-catenin with loss of total cellular E-cadherin expression in p53 mutant cancer cells, but not in p53 wild-type cancer cells. These changes in the invasion index by p53R2 siRNA transfection were not accompanied by alterations in MMP activity and expression. These results suggested that the expression of p53R2 could be associated with the invasion of cancer cells, and indicated that p53R2 might promote cancer invasion via the E-cadherin/beta-catenin pathway without the alteration of MMP activity.