Reduced membranous and ectopic cytoplasmic expression of beta -catenin correlate with cyclin D1 overexpression and poor prognosis in pancreatic cancer

PNU-74654 Induces Cell Cycle Arrest and Inhibits EMT Progression in Pancreatic Cancer

Background and Objectives: PNU-74654, a Wnt/β-catenin pathway inhibitor, has an antiproliferative effect on many cancer types; however, its therapeutic role in pancreatic cancer (PC) has not yet been demonstrated. Here, the effects of PNU-74654 on proliferation and cell cycle phase distribution were studied in PC cell lines. Materials and Methods: The cancer-related molecular pathways regulated by PNU-74654 were determined by a proteome profiling oncology array and confirmed by western blotting. Results: The cell viability and proliferative ability of PC cells were decreased by PNU-74654 treatment. G1 arrest was observed, as indicated by the downregulation of cyclin E and cyclin-dependent kinase 2 (CDK2) and the upregulation of p27. PNU-74654 inhibited the epithelial-mesenchymal transition (EMT), as determined by an increase in E-cadherin and decreases in N-cadherin, ZEB1, and hypoxia-inducible factor-1 alpha (HIF-1α). PNU-74654 also suppressed cytoplasmic and nuclear β-catenin and impaired the NF-κB pathway. Conclusions: These results demonstrate that PNU-74654 modulates G1/S regulatory proteins and inhibits the EMT, thereby suppressing PC cell proliferation, migration, and invasion. The synergistic effect of PNU-74654 and chemotherapy or the exclusive use of PNU-74654 may be therapeutic options for PC and require further investigation.

Implication of ERBB2 as a Predictive Tool for Survival in Patients with Pancreatic Cancer in Histological Studies

Pancreatic cancer will be positioned by the year 2030 as the second cause of oncological death after lung cancer. The pathophysiology of the most common variety, which involves the adenocarcinoma of the pancreas, represents one of the main challenges for current oncology to explain its tumorigenesis and create a targeted treatment. The tumor microenvironment, metastatic capacity, and lack of early diagnosis lead patients to present advanced stages at the time of diagnosis. Despite numerous efforts, little progress has been made in clinical outcomes and with respect to the improved survival of these patients. For this reason, in recent years, numerous diagnostic tests, treatments, and possible approaches in the fields of radiotherapy, chemotherapy, immunotherapy, and surgery have been developed to find a combination of methods that improves life expectancy in patients diagnosed with this disease. On the other hand, the scientific community has made numerous advances in the molecular bases of pancreatic cancer since several oncogenetic pathways have been described and the markers expressed by the tumor have proven to be useful in the prognosis of pancreatic adenocarcinoma. These molecular alterations allow the study of possible therapeutic targets that improve the prognosis of these patients, but even numerous tumor cell-individual interactions must be explained to understand the underlying pathophysiology causing the high mortality. Therefore, the purpose of our study is to examine the expression of markers such as EGFR, Cyclin D1, andCDK4 in order to find a relationship with the possible long-term prognostic factors of patients affected by pancreatic ductal adenocarcinoma. Our results show that there is a prognostic role for ErbB2, EGFR, beta catenin, cyclin D1, and CDK4. Of these, we highlight the clinical importance of ErbB2 in the survival rates of patients who overexpress this component.

Silybum marianum total extract, silymarin and silibinin abate hepatocarcinogenesis and hepatocellular carcinoma growth via modulation of the HGF/c-Met, Wnt/β-catenin, and PI3K/Akt/mTOR signaling pathways

Hepatocellular carcinoma (HCC) has been identified as one of the most deadly malignancies with limited therapeutic efficacy worldwide. However, understanding the molecular mechanisms of crosstalk between signaling pathways in HCC and predicting cancer cell responses to targeted therapeutic interventions remain to be challenge. Thus, in this study, we aimed to evaluate the anticancerous efficacy of Silybum marianum total extract (STE), silymarin (Sm), and silibinin (Sb) against experimentally-induced HCC in rats. In vitro investigations were also performed and the anticancer effects against HCC cell lines (HepG2 and Huh7) were confirmed. Wistar rats were given diethylnitrosamine (DEN)/2-acetylaminofluorene (AAF)/carbon tetrachloride (CCl4) and were orally treated with STE (200 mg/kg body weight (bw)), Sm (150 mg/kg bw), and Sb (5 mg/kg bw) every other day from the 1st or 16th week to the 25th week of DEN/AAF/CCl4 injection. Treatment with STE, Sm, and Sb inhibited the growth of cancerous lesions in DEN/AAF/CCl4-treated rats. This inhibition was associated with inhibition of Ki-67 expression and repression of HGF/cMet, Wnt/β-catenin, and PI3K/Akt/mTOR signaling pathways. STE, Sm, and Sb improved liver function biomarkers and tumor markers (AFP, CEA, and CA19.9) and increased total protein and albumin levels in serum. STE, Sm, and Sb treatment was also noted to reduce the hepatic production of lipid peroxides, increase hepatic glutathione content, and induce the activities of hepatic antioxidant enzymes in DEN/AAF/CCl4-treated rats. These results indicate that STE, Sm, and Sb exert anti-HCC effects through multiple pathways, including suppression of Ki-67 expression and HGF/cMet, Wnt/β-catenin, and PI3K/Akt/mTOR pathways and enhancement of antioxidant defense mechanisms.

β-catenin plus PROX1 immunostaining stratifies disease progression and patient survival in neoadjuvant-treated pancreatic cancer

BACKGROUND

Wnt/β-catenin signaling is a highly conserved signaling pathway that regulates the transcription factor PROX1. The role of β-catenin and PROX1 in pancreatic cancer is ambiguous, as some studies have associated their expression with tumor regression and some with tumor progression.

OBJECTIVE

We have investigated their expression in surgically treated pancreatic cancer patients receiving neoadjuvant therapy (NAT), and patients treated upfront with surgery (US). We furthermore compared the expression of β-catenin and PROX1 between patients who had a good or poor response to NAT.

METHODS

We evaluated β-catenin and PROX1 expression through immunohistochemistry in 88 neoadjuvant and 144 upfront surgery patients by scoring the intensity of the immunopositivity as 0-3, corresponding to negative, weak, moderate, or strong. We developed a six-tier grading scheme for the neoadjuvant responses by analyzing the remaining tumor cells in surgical specimen histological sections.

RESULTS

Strong β-catenin immunopositivity associated with improved survival in the patients with good NAT-response (≤10% residual tumor cells) (Hazard ratio [HR] 0.26 95%, confidence interval [CI] 0.07-0.88 p = 0.030). Additionally, the combined moderate β-catenin and PROX1 expression associated with improved survival (HR 0.20 95% CI 0.05-0-76 p = 0.018) among the good responders. Among the patients with a poor NAT-response (> 10% residual tumor cells), both strong β-catenin immunopositivity and strong combined β-catenin and PROX1 associated with shorter survival (HR 2.03 95% CI 1.16-3.55 p = 0.013, and HR 3.1 95% CI 1.08-8.94 p = 0.03, respectively). PROX1 alone was not associated with survival.

CONCLUSIONS

Strong β-catenin immunopositivity and combined strong or moderate β-catenin and PROX1 immunopositivity associated with improved survival among the good NAT-responders and worse survival among the poor NAT-responders.

Prognostic impact of the expression of Wnt-signaling proteins in cervical carcinoma FIGO stage I-IV treated with radiotherapy or chemoradiotherapy

Wnt signaling proteins were assessed in patients with primary cervical carcinomas who received chemoradiation. The associations between three Wnt signaling proteins and prognosis were assessed. Specimens from 122 patients with cervical carcinomas (FIGO stage I-IV) were immunohistochemically (IHC) analyzed for β-catenin, APC and axin protein expression. Associations between these Wnt-protein expressions, clinicopathological factors, and clinical outcome data were examined.

Positive IHC staining for the β-catenin protein (cell-membranes, cytoplasm and nuclei) was recorded in 88%, 58% and 5%, respectively. There was a strong association between β-catenin staining of the cell-membranes and prediction of recurrences and prognosis (p = 0. 002). Tumors with > 5% of nuclear β-catenin staining were associated with inferior cancer-specific survival (p = 0.048) compared with no staining. The overall recurrence rate was significantly higher in the group with increased nuclear staining (67%) compared with the group with no staining (33%). Nuclear APC staining of high intensity was associated with a significantly worse cancer-specific survival and increased overall recurrence rate compared to tumors with weak staining. Distant recurrences were recorded in 29% of cases with intense staining and in 14% of cases with low staining.

The Wnt signaling pathway seems to be of importance in the process of cervical oncogenesis. A predictive and prognostic value was found for β-catenin, where strong cell-membrane staining was favorable, and > 5% positive nuclear staining was associated with poorer cancer-specific survival and overall recurrence rate. Nuclear APC staining intensity was also associated with a less favorable prognosis.

YEATS4 promotes the tumorigenesis of pancreatic cancer by activating beta-catenin/TCF signaling

Beta-catenin/TCF signaling has been reported to promote the growth and metastasis of pancreatic cancer cells. However, the regulation for the beta-catenin/TCF transcriptional complex remains largely unknown. Here, we have found that YEATS4 is a positive regulator for Beta-catenin/TCF signaling. The expression of YEATS4 was elevated in clinical pancreatic cancer samples and pancreatic cancer mouse model. Up-regulation of YEATS4 promoted the growth, migration and invasion of pancreatic cancer cells, while knocking down the expression of YEATS4 inhibited the growth, migration, invasion and metastasis of pancreatic cancer cells. Moreover, the mechanism study revealed that YEATS4 interacted with beta-catenin and activated beta-catenin/TCF signaling. Furthermore, knocking down the expression of YEATS4 impaired the malignant transformation of normal pancreatic cells (HPDE6C7) by the oncogenic Ras. Taken together, our study demonstrated the oncogenic roles of YEATS4 in the progression of pancreatic cancer by activating beta-catenin/TCF signaling and suggested that YEATS4 might be a promising therapeutic target for pancreatic cancer.

FH535, a β-catenin pathway inhibitor, represses pancreatic cancer xenograft growth and angiogenesis

The WNT/β-catenin pathway plays an important role in pancreatic cancer carcinogenesis. We evaluated the correlation between aberrant β-catenin pathway activation and the prognosis pancreatic cancer, and the potential of applying the β-catenin pathway inhibitor FH535 to pancreatic cancer treatment. Meta-analysis and immunohistochemistry showed that abnormal β-catenin pathway activation was associated with unfavorable outcome. FH535 repressed pancreatic cancer xenograft growth in vivo. Gene Ontology (GO) analysis of microarray data indicated that target genes responding to FH535 participated in stemness maintenance. Real-time PCR and flow cytometry confirmed that FH535 downregulated CD24 and CD44, pancreatic cancer stem cell (CSC) markers, suggesting FH535 impairs pancreatic CSC stemness. GO analysis of β-catenin chromatin immunoprecipitation sequencing data identified angiogenesis-related gene regulation. Immunohistochemistry showed that higher microvessel density correlated with elevated nuclear β-catenin expression and unfavorable outcome. FH535 repressed the secretion of the proangiogenic cytokines vascular endothelial growth factor (VEGF), interleukin (IL)-6, IL-8, and tumor necrosis factor-α, and also inhibited angiogenesis in vitro and in vivo. Protein and mRNA microarrays revealed that FH535 downregulated the proangiogenic genes ANGPT2, VEGFR3, IFN-γ, PLAUR, THPO, TIMP1, and VEGF. FH535 not only represses pancreatic CSC stemness in vitro, but also remodels the tumor microenvironment by repressing angiogenesis, warranting further clinical investigation.

Identfication of key miRNAs in pancreatitis using bioinformatics analysis of microarray data

Pancreatitis is a type of inflammation in the pancreas, which frequently occurs due to alcohol and gallstones. The present study aimed to identify pancreatitis-associated microRNAs (miRNAs) by analyzing the microarray of GSE24279. GSE24279 was downloaded from the Gene Expression Omnibus, composed of a collective of 27 pancreatitis and 22 normal control samples. The differentially expressed miRNAs (DE-miRNAs) in pancreatitis samples were screened using the Limma package in Bioconductor. Subsequently, target genes of the DE-miRNAs were predicted using the miRecords and miRWalk databases. Their potential functions were analyzed by functional and pathway enrichment analysis using the Database for Annotation, Visualization and Integrated Discovery online tool. Finally, pancreatitis-associated genes among the target genes identified were searched using the Comparative Toxicogenomics Database, and a regulatory network of pancreatitis-associated genes and their target miRNAs were constructed using Cytoscape software. A total 14 upregulated and 39 downregulated miRNAs were identified in pancreatitis samples compared with control samples and 290 target genes of DE-miRNAs were determined. Cyclin D1 (CCND1), v-akt murine thymoma viral oncogene homolog 2 (AKT2), cyclin-dependent kinase 6 (CDK6) and SMAD family member 2 (SMAD2) were involved in the pathway of pancreatic cancer. Among the target genes, 279 genes were pancreatitis-associated genes, which in turn were targeted by 37 miRNAs in the regulatory network. Hsa-miR-15a, hsa-miR-16, hsa-miR-155, hsa-miR-375 and hsa-miR-429 in particular may be involved in pancreatitis by targeting genes in the regulatory network, including hsa-miR-15a→CCND1, hsa-miR-16→CCND1, hsa-miR-155→CCND1/SMAD2, hsa-miR-375→AKT2/CDK6 and hsa-miR-429→CCND1. The above miRNAs and their targets may contribute to the pathogenesis of pancreatitis; therefore, they may be potential therapeutic targets.

PROX1 and β-catenin are prognostic markers in pancreatic ductal adenocarcinoma

Background

The Wnt/β-catenin pathway has a key role in regulating cellular processes and its aberrant signaling can lead to cancer development. The role of β-catenin expression in pancreatic ductal adenocarcinoma is somewhat controversial. Transcription factor PROX1 is a target of Wnt/β-catenin signaling and it is involved in carcinogenesis through alterations in its expression. The actions can be either oncogenic or tumor suppressive depending on the tissue. The aim of this study was to investigate PROX1 and β-catenin expression in pancreatic ductal adenocarcinoma (PDAC).

Methods

Expression of PROX1 and β-catenin were evaluated in 156 patients by immunohistochemistry of tissue microarrays. Associations between tumor marker expression and clinicopathological parameters were assessed by the Fischer’s exact-test or the linear-by-linear association test. The Kaplan-Meier method and log-rank test were used for survival analysis. Uni- and multivariate survival analyses were carried out by the Cox regression proportional hazard model.

Results

High PROX1 expression was seen in 74 (48 %) tumors, and high β-catenin expression in 100 (65 %). High β-catenin expression was associated with lower tumor grade (p = 0.025). High PROX1 and β-catenin expression associated significantly with lower risk of death from PDAC in multivariate analysis (HR = 0.63; 95 % CI 0.42–0.95, p = 0.026; and HR = 0.54; 95 % CI 0.35–0.82, p = 0.004; respectively). The combined high expression of PROX1 and β-catenin also predicted lower risk of death from PDAC (HR = 0.46; 95 % CI 0.28–0.76, p = 0.002).

Conclusion

In conclusion, high PROX1 and β-catenin expression were independent factors for better prognosis in pancreatic ductal adenocarcinoma.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2497-5) contains supplementary material, which is available to authorized users.

Clinicopathological Implications of Wingless/int1 (WNT) Signaling Pathway in Pancreatic Ductal Adenocarcinoma

Pancreatic cancer is still one of the most lethal malignancies in the world, and a more thorough understanding of its detailed pathogenetic mechanisms and the development of more effective therapeutic strategies are urgently required. Pancreatic ductal adenocarcinoma (PDA), the most common type of pancreatic cancer, is characterized by consistent genetic abnormalities such as point mutations in the Kirsten rat sarcoma viral oncogene homolog (KRAS) and in the tumor suppressor protein p53 (TP53) genes. Alterations in intracellular core signal pathways have also been shown to induce the development or progression of PDA. The Wingless/int1 (WNT) signal pathway plays a pivotal role in embryonic development, cellular proliferation and differentiation, and dysregulation of WNT signaling can lead to neoplastic transformation in a variety of organ systems, including the pancreas. Recent studies have shown that altered WNT signaling is associated with a poor prognosis in patients with PDA, suggesting that the pathway is a predictor of patients' survival and a potential therapeutic target of PDA. In this review, the clinicopathological implications of WNT signaling in PDA are highlighted.

The canonical Wnt pathway regulates the metastasis-promoting mucin MUC4 in pancreatic ductal adenocarcinoma

Aberrant Wnt signaling frequently occurs in pancreatic cancer (PC) and contributes to disease progression/metastases. Likewise, the transmembrane-mucin MUC4 is expressed de novo in early pancreatic intraepithelial neoplasia (PanINs) and incrementally increases with PC progression, contributing to metastasis. To determine the mechanism of MUC4 upregulation in PC, we examined factors deregulated in early PC progression, such as Wnt/β-catenin signaling. MUC4 promoter analysis revealed the presence of three putative TCF/LEF-binding sites, leading us to hypothesize that MUC4 can be regulated by β-catenin. Immunohistochemical (IHC) analysis of rapid autopsy PC tissues showed a correlation between MUC4 and cytosolic/nuclear β-catenin expression. Knock down (KD) of β-catenin in CD18/HPAF and T3M4 cell lines resulted in decreased MUC4 transcript and protein. Three MUC4 promoter luciferase constructs, p3778, p3000, and p2700, were generated. The construct p3778, encompassing the entire MUC4 promoter, elicited increased luciferase activity in the presence of stabilized β-catenin. Mutation of the TCF/LEF site closest to the transcription start site (i.e., -2629/-2612) and furthest from the start site (i.e., -3425/-3408) reduced MUC4 promoter luciferase activity. Transfection with dominant negative TCF4 decreased MUC4 transcript and protein levels. Chromatin immunoprecipitation confirmed enrichment of β-catenin on -2629/-2612 and -3425/-3408 of the MUC4 promoter in CD18/HPAF. Functionally, CD18/HPAF and T3M4 β-catenin KD cells showed decreased migration and decreased Vimentin, N-cadherin, and pERK1/2 expression. Tumorigenicity studies in athymic nude mice showed CD18/HPAF β-catenin KD cells significantly reduced primary tumor sizes and metastases compared to scrambled control cells. We show for the first time that β-catenin directly governs MUC4 in PC.

Downregulation of miR-610 promotes proliferation and tumorigenicity and activates Wnt/β-catenin signaling in human hepatocellular carcinoma

BACKGROUND

Wnt/β-catenin signaling pathway plays important roles in human cancer progression. Better understanding the mechanism underlying regulation of Wnt/β-catenin signaling pathway might provide novel therapeutic targets for cancer treatment.

METHODS

miR-610 expression levels in hepatocellular carcinoma (HCC) cell lines, HCC tissues and 76 archived HCC specimens were determined using real-time PCR. Cell viability was measured by 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay. The level of DNA synthesis was determined by BrdU incorporation assay. Flow cytometry analysis was used to analyze cell cycle progression. The cells proliferation and tumorigenesis were determined by colony formation and anchorage-independent growth assays in vitro, and by xenograft tumors in vivo. Luciferase assay and micro-ribonucleoprotein complex immunoprecipitation assay were used to confirm the association of the targeted mRNAs with miR-610.

RESULTS

miR-610 was downregulated in human HCC cells and tissues, and correlated with HCC progression and patient survival. Inhibition of miR-610 promoted, but overexpression of miR-610 reduced, HCC cell proliferation and tumorigenicity both in vitro and in vivo. Furthermore, we found that inhibiting miR-610 activated, but overexpressing miR-610 decreased, the Wnt/β-catenin activity through directly suppressing lipoprotein receptor-related protein 6 (LRP6) and transducin β-like protein 1 (TBL1X). The in vitro analysis was consistent with the inverse correlation detected between miR-610 levels with expression of LRP6 and TBL1X in a cohort of human HCC samples.

CONCLUSIONS

Our results indicate that miR-610 downregulation plays essential roles in HCC progression and reduced miR-610 is correlated with Wnt/β-catenin signaling pathway.

Cyclin D1, p16(INK) (4A) and p27(Kip1) in pancreatic adenocarcinoma: assessing prognostic implications through quantitative image analysis

The prognostic significance of cyclin D1, p16(INK) (4A) and p27(Kip1) expression has been documented in several human malignancies; however, their prognostic potential in pancreatic adenocarcinoma is still unclear. This study aimed to assess the correlation of the aforementioned molecules with clinicopathological parameters and prognosis. Sixty patients with pancreatic ductal adenocarcinoma underwent surgical resection at a single institution; immunohistochemical staining of the studied markers was quantified by Ιmage analysis system. Cyclin D1 overexpression was positively associated with grade, neural infiltration and vascular invasion, whereas p27 positively correlated with age. Higher cyclin D1 expression indicated poorer survival (adjusted HR = 9.75, 95%CI: 1.48-64.31, p = 0.018, increment: one unit in H-score), whereas a marginal trend toward an association between p16 positivity and improved survival was observed (adjusted HR = 0.58, 95%CI: 0.32-1.05, p = 0.072 regarding positive vs negative cases). No significant association with overall survival was noted regarding p27. In conclusion, cyclin D1 overexpression and possibly p16 loss of expression in pancreatic adenocarcinoma seem to be adverse prognostic factors, whereas p27 expression did not seem to possess such prognostic properties. Further validation of the present findings in studies encompassing larger samples seems to be needed.

Reversion of trichostatin A resistance via inhibition of the Wnt signaling pathway in human pancreatic cancer cells

Drug resistance is a major impediment to successful chemotherapy in pancreatic cancer (PC) patients. We investigated the effect of Wnt/β-catenin signaling inhibition by wnt-c59 on chemoresistance in a trichostatin A-resistant Panc-1 cell line (Panc-1/TSA). Panc-1/TSA cells were treated with the Wnt/β‑catenin signaling inhibitor wnt-c59 (10 µmol · l-1) and/or trichostatin A (TSA; 10 µmol · l-1) for 24 h. CCK-8 assay was utilized to analyze the interactive effect of TSA and wnt-c59 on induction of apoptosis of the Panc-1/TSA cells. Cell apoptosis was measured by flow cytometry. Real-time PCR and western blotting were used to assess Wnt/β-catenin signaling, epithelial-mesenchymal transition (EMT) and multidrug resistance (MDR). Real-time cell analysis (RTCA) was used to detect the cell migration ability. After wnt-c59 treatment for 24 h, relative genes and transcriptional targets of Wnt/β-catenin signaling were downregulated (P<0.05). CCK-8 assay indicated that the combination of TSA and wnt-c59 had a synergistic effect on induction of Panc-1/TSA cell apoptosis. As detected by FACS, cell apoptosis rates increased significantly (P<0.05). The results of RTCA showed that the cell indices of the control group, wnt-c59 group, TSA group and TSA+wnt-c59 combination group were 1.2842±0.0257, 1.2155±0.0282, 1.2533±0.0194 and 0.8541±0.0250, respectively. In accordance, MMP-9 protein in the wnt-c59 treatment groups was decreased compared to the non-wnt-c59 treatment groups. Meanwhile, E-cadherin protein was upregulated and vimentin protein was downregulated, both of which are characteristic markers of EMT. Chemoresistant gene MDR1 and P-glycoprotein (P-gp) in the wnt-c59 treatment groups had a reduced expression compared to the non-wnt-c59 treatment groups. This study revealed that TSA sensitivity, migration ability, and the EMT phenotype in Panc-1/TSA cells were reversed following Wnt/β-catenin signaling inhibition.

Prognostic significance of WNT signaling in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDA) is one of the most lethal human malignancies and is associated with a variety of molecular abnormalities. Although WNT signaling through its canonical/non-canonical pathways is one of the major factors involved in oncogenesis or progression of PDA, the prognostic significance of WNT signaling still remains poorly investigated. In this study, the status of the WNT signaling pathways was immunohistochemically analyzed in 101 PDAs, and its potential association with patient postoperative survival was assessed. Nuclear expression of beta-catenin, a hallmark of the activated canonical pathway, was identified in 59 cases, and was associated with reduced survival compared to the patients lacking nuclear beta-catenin expression (P = 0.002). In contrast, activation of the non-canonical pathway (25 cases), as indicated by co-expression of WNT2/5a and nuclear NFATc1, was not correlated with reduced survival (P = 0.268). Co-activation of both pathways (16 cases) was associated with worse prognosis in comparison with cases with an activated non-canonical pathway (P = 0.034). In addition, nuclear beta-catenin expression was an independent unfavorable prognostic factor (P = 0.006). Our data indicate that activated WNT signaling through its canonical pathway has a significantly negative effect on the clinical course of PDA, and the canonical WNT pathway should be considered as a future therapeutic target for PDA.

PP2A inhibitors suppress migration and growth of PANC-1 pancreatic cancer cells through inhibition on the Wnt/β-catenin pathway by phosphorylation and degradation of β-catenin

Cantharidin is an active constituent of mylabris, a traditional Chinese medicine, and presents strong anticancer activity in various cell lines. Cantharidin is a potent and selective inhibitor of serine/threonine protein phosphatase 2A (PP2A). Our previous studies revealed the prospect of application of cantharidin, as well as other PP2A inhibitors, in the treatment of pancreatic cancer. However, the mechanisms involved in the anticancer effect of PP2A inhibitors have not been fully explored. The Wnt/β-catenin pathway is involved in cell migration and proliferation and participates in the progression of pancreatic cancer. If β-catenin is phosphorylated and degraded, the Wnt/β-catenin pathway is blocked. PP2A dephosphorylates β-catenin and keeps the Wnt/β-catenin pathway active. In the present study, we found that PP2A inhibitor treatment induced phosphorylation and degradation of β-catenin. The suppression on the migration and growth of PANC-1 pancreatic cancer cells could be attenuated by pretreatment with FH535, a β-catenin pathway inhibitor. Microarray showed that PP2A inhibitor treatment induced expression changes in 13 of 138 genes downstream of the β-catenin pathway. Real-time PCR further confirmed that FH535 attenuated the expression changes induced by PP2A inhibitors in 6 of these 13 candidate genes. These 6 genes, VEGFB, Dkk3, KRT8, NRP1, Cacnalg and WISP2, have been confirmed to participate in the migration and/or growth regulation in previous studies. Thus, the phosphorylation- and degradation-mediated suppression on β-catenin participates in the cytotoxicity of PP2A inhibitors. Our findings may provide insight into the treatment of pancreatic cancer using a targeting PP2A strategy.

TWIST1 and SNAI1 as markers of poor prognosis in human colorectal cancer are associated with the expression of ALDH1 and TGF-β1

Epithelial-mesenchymal transition (EMT) is an important factor in cancer invasiveness and metastatic progression. During EMT, cancer cells acquire stem cell properties. The role of EMT and stemness in colon cancer has not been fully understood. We aimed to demonstrate the clinical significance of EMT and the stem cell phenotype in colorectal cancer. Two hundred and thirty-one surgically resected colon cancer cases were included in the present study. mRNAs of E-cadherin, TWIST1 and SNAI1 were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) (n=109). Immunohistochemical staining was performed for six markers (ALDH1, TGF-β1, E-cadherin, β-catenin, TWSIT1 and SNAI1) (n=231). We assessed clinicopathological characteristics according to the expression of the stem cell phenotype and EMT markers. Based on the results of qRT-PCR, TWIST1 and SNAI1 significantly influenced node metastasis (P=0.04 and P=0.02, respectively). High TWIST1 and SNAI1 mRNA expression was associated with poor overall survival according to the univariate analysis (P<0.01 and P=0.01, respectively) and the multivariate analysis (P=0.04 and P=0.04, respectively). ALDH1 expression as detected by immunohistochemical staining was associated with high nodal stage, advanced clinical stage, lymphatic invasion and poor survival (P=0.01, P=0.04, P<0.05 and P<0.01, respectively) and with the expression of TGF-β1 and β-catenin. In conclusion, in human colorectal cancer, the EMT markers TWIST1 and SNAI1 are suggested as important markers of poor prognosis. Their expression is associated with the expression of putative stem cell marker ALDH1, and ALDH1 is associated with the expression of TGF-β1.

Uterine fibroids: pathogenesis and interactions with endometrium and endomyometrial junction

Uterine leiomyomas (fibroids or myomas) are benign tumors of uterus and clinically apparent in a large part of reproductive aged women. Clinically, they present with a variety of symptoms: excessive menstrual bleeding, dysmenorrhoea and intermenstrual bleeding, chronic pelvic pain, and pressure symptoms such as a sensation of bloatedness, increased urinary frequency, and bowel disturbance. In addition, they may compromise reproductive functions, possibly contributing to subfertility, early pregnancy loss, and later pregnancy complications. Despite the prevalence of this condition, myoma research is underfunded compared to other nonmalignant diseases. To date, several pathogenetic factors such as genetics, microRNA, steroids, growth factors, cytokines, chemokines, and extracellular matrix components have been implicated in the development and growth of leiomyoma. This paper summarizes the available literature regarding the ultimate relative knowledge on pathogenesis of uterine fibroids and their interactions with endometrium and subendometrial myometrium.

LRP5 knockdown: effect on prostate cancer invasion growth and skeletal metastasis in vitro and in vivo

Prostate cancer (PCa) is a common hormone-dependent malignancy associated with the development of skeletal metastases. This is due to the increased expression of a number of growth factors, cytokines, and proteases which collectively drive the metastatic cascade in general and increased propensity to develop skeletal metastasis in particular. While a number of signaling pathways have been implicated in PCa progression, the highly complex wnt/β-catenin pathway is unique due to its ability to regulate gene expression, cell invasion, migration, survival, proliferation, and differentiation to contribute in the initiation and progression of PCa. Members of the wnt family bind to the Frizzle proteins or lipoprotein-related receptor proteins 5, 6 (LRP5, -6) to activate this key pathway. In the current study, we have investigated the role of wnt/β-catenin pathway in PCa progression, skeletal metastasis, and gene expression using the dominant negative plasmid of LRP5 (DN-LRP5) and human PCa cells PC-3. Inactivation of LRP5 resulted in mesenchymal to epithelial shift, lack of translocation of β-catenin to cell surface, increased tumor cell proliferation, decreased colony formation, migration and invasion in vitro. These effects were attributed to decreased expression of pro-invasive and pro-metastatic genes. In in vivo studies, PC-3-DN-LRP5 cells developed significantly smaller tumors and a marked decrease in skeletal lesion area and number as determined by X-ray, micro (μ) CT and histological analysis. Collectively results from these studies demonstrate the dominant role of this key pathway in PCa growth and skeletal metastasis and its potential as a viable therapeutic target.

The influence of matrix properties on growth and morphogenesis of human pancreatic ductal epithelial cells in 3D

A highly tunable synthetic biomimetic hydrogel platform was developed to study the growth and morphogenesis of pancreatic ductal epithelial cells (PDEC) under the influence of a myriad of instructive cues. A PDEC line, PANC-1, was used as a model system to illustrate the importance of matrix compositions on cell fate determination. PANC-1 is an immortalized ductal epithelial cell line widely used in the study of pancreatic tumor cell behaviors. PANC-1 cells are also increasingly explored as a potential cell source for endocrine differentiation. Thus far, most studies related to PANC-1, among other PDEC lines, are performed on 2D culture surfaces. Here, we evaluated the effect of matrix compositions on PANC-1 cell growth and morphogenesis in 3D. Specifically, PANC-1 cells were encapsulated in PEG-based hydrogels prepared by step-growth thiol-ene photopolymerization. It was found that thiol-ene hydrogels provided a cytocompatible environment for encapsulation and 3D culture of PANC-1 cells. In contrast to a monolayer morphology on 2D culture surfaces, PANC-1 cells formed clusters in 3D thiol-ene hydrogels within 4 days of culture. After culturing for 10 days, however, the growth and structures of these clusters were significantly impacted by gel matrix properties, including sensitivity of the matrix to proteases, stiffness of the matrix, and ECM-mimetic motifs. The use of matrix metalloproteinase (MMP) sensitive linker or the immobilization of fibronectin-derived RGDS ligand in the matrix promoted PANC-1 cell growth and encouraged them to adopt ductal cyst-like structures. On the other hand, the encapsulated cells formed smaller and more compact aggregates in non-MMP responsive gels. The incorporation of laminin-derived YIGSR peptide did not enhance cell growth and caused the cells to form compact aggregates. Immobilized YIGSR also enhanced the expression of epithelial cell markers including β-catenin and E-cadherin. These studies have established PEG-peptide hydrogels formed by thiol-ene photo-click reaction as a suitable platform for studying and manipulating pancreatic epithelial cell growth and morphogenesis in 3D.

Clinical implications of biological markers in Pancreatic Ductal Adenocarcinoma

Pancreatic Ductal Adenocarcinoma (PDAC) is a malignant neoplasm and is the fourth leading cause of cancer-related deaths in US with a 5-year survival rate less than 5%. Surgery is the only potentially curative treatment even though the result is a palliation in the majority of cases and the majority of lesions are lately diagnosed. Progression from normal pancreatic epithelium to metastatic disease is now a well-characterized sequence of events. Research has shown that pancreatic cancer is fundamentally a genetic disease with several biological pathway implied in apoptosis, cell proliferation and self-sufficiency in growth signaling, but how those findings could be applied in daily clinical practice remain unknown. Several studies tried to characterize diagnostic and prognostic biomarkers in PDAC to make it possible an earlier diagnosis, guarantee a more effective treatment and reach a better prognosis even though the results remain contrasting. The main limit of the published researches is the small number of patients studied, but even the heterogeneity of the used methods of analysis. Examining critically the research of the last years future trials may be addressed toward a translational models integrating "the bench and the bed" with the clinical experience and drive the basic research toward the clinical applications.

MED12 alterations in both human benign and malignant uterine soft tissue tumors

The relationship between benign uterine leiomyomas and their malignant counterparts, i.e. leiomyosarcomas and smooth muscle tumors of uncertain malignant potential (STUMP), is still poorly understood. The idea that a leiomyosarcoma could derive from a leiomyoma is still controversial. Recently MED12 mutations have been reported in uterine leiomyomas. In this study we asked whether such mutations could also be involved in leiomyosarcomas and STUMP oncogenesis. For this purpose we examined 33 uterine mesenchymal tumors by sequencing the hot-spot mutation region of MED12. We determined that MED12 is altered in 66.6% of typical leiomyomas as previously reported but also in 11% of STUMP and 20% of leiomyosarcomas. The mutated allele is predominantly expressed in leiomyomas and STUMP. Interestingly all classical leiomyomas exhibit MED12 protein expression while 40% of atypical leiomyomas, 50% of STUMP and 80% of leiomyosarcomas (among them the two mutated ones) do not express MED12. All these tumors without protein expression exhibit complex genomic profiles. No mutations and no expression loss were identified in an additional series of 38 non-uterine leiomyosarcomas. MED12 mutations are not exclusive to leiomyomas but seem to be specific to uterine malignancies. A previous study has suggested that MED12 mutations in leiomyomas could lead to Wnt/β-catenin pathway activation however our immunohistochemistry results show that there is no association between MED12 status and β-catenin nuclear/cytoplasmic localization. Collectively, our results show that subgroups of benign and malignant tumors share a common genetics. We propose here that MED12 alterations could be implicated in the development of smooth muscle tumor and that its expression could be inhibited in malignant tumors.

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.

Pancreatic ductal adenocarcinoma and transcription factors: role of c-Myc

INTRODUCTION

Deregulated expression/activation of transcription factors is a key event in the establishment and progression of human cancer. Furthermore, most oncogenic signaling pathways converge on sets of transcription factors that ultimately control gene expression patterns resulting in cancer development, progression, and metastasis.

METHODS

Ductal pancreatic adenocarcinoma (PDA) is the main type of pancreatic cancer and the fourth leading cause of cancer mortality in the Western world. The early stage of the disease is characterized by pancreatic intraepithelial neoplasia lesions bearing mutations in the K-RAS proto-oncogene, which progress to malignant PDA by accumulating additional mutations in the tumor suppressor gene CDKN2A (p16) and in SMAD4 and TP53 transcription factors. The involvement of other signaling pathways in PDA development and progression is an active area of research which may help to clarify the critical steps of this devastating disease.

RESULTS

In this regard, several in vitro and in vivo data have demonstrated the contribution of the transcription factor c-Myc to pancreatic carcinogenesis although the molecular mechanisms are poorly understood. c-Myc is a proto-oncogene which has a pivotal function in growth control, differentiation and apoptosis and is known to act as a downstream transcriptional effector of many signaling pathways involved in these processes. It is regulated at multiple levels and its abnormal expression contributes to the genesis of many human tumors.

CONCLUSIONS

This review focuses on the role of c-Myc in pancreatic embryonic development and homeostasis as well as its involvement on pancreatic tumorigenesis. Evidences showing that c-Myc function is highly dose and cell context dependent, together with its recently demonstrated ability to reprogram somatic cells towards a pluripotent stem cell-like state, indicate that the role of c-Myc in pancreas pathophysiology might have been previously underscored.

Tissue biomarkers for prognosis in pancreatic ductal adenocarcinoma: a systematic review and meta-analysis

PURPOSE

The management of pancreatic ductal adenocarcinoma (PDAC) continues to present a great challenge particularly with regard to prediction of outcome following pancreaticoduodenectomy. Molecular markers have been extensively investigated by numerous groups with the aim of enhancing prognostication; however, despite hundreds of studies that have sought to assess the potential prognostic value of molecular markers in predicting the clinical course following resection of PDAC, at this time, no molecular marker assay forms part of recommended clinical practice.

EXPERIMENTAL DESIGN

We conducted a systematic review and meta-analysis of the published literature for immunohistochemistry-based biomarkers of PDAC outcome. A dual search strategy was applied to the PubMed database on January 6, 2010, to identify cohort studies that reported associations between immunohistochemical biomarker expression and survival outcomes in PDAC, and conformed to the REMARK (REporting recommendations for tumor MARKer prognostic studies) criteria.

RESULTS

A total of 103 distinct proteins met all inclusion criteria. Promising markers that emerged for the prediction of overall survival included BAX (HR = 0.31, 95% CI: 0.71-0.56), Bcl-2 (HR = 0.41, 95% CI: 0.27-0.63), survivin (HR = 0.46, 95% CI: 0.29-0.73), Ki-67: (HR = 2.42, 95% CI: 1.87-3.14), COX-2 (HR = 1.39, 95% CI: 1.13-1.71), E-cadherin (HR = 1.80, 95% CI: 1.33-2.42), and S100 calcium-binding proteins, in particular S100A2 (HR = 3.23, 95% CI: 1.58-6.62).

CONCLUSIONS

We noted that that there was incomplete adherence to the REMARK guidelines with inadequate methodology reporting as well as failure to perform multivariate analysis. Addressing the persistent incomplete adoption of these criteria may eventually result in the incorporation of molecular marker assessment within PDAC management algorithms.

CRH and SRIF have opposite effects on the Wnt/β-catenin signalling pathway through PKA/GSK-3β in corticotroph pituitary cells

The Wnt/ß-catenin signalling pathway is involved in tumorigenesis including endocrine tumors. We investigated the Wnt/ß-catenin pathway's modulation by corticotropin-releasing hormone (CRH) and somatostatin or somatotropin release-inhibiting factor (SRIF) in mouse pituitary AtT-20 corticotroph cells. The Wnt/β-catenin signalling pathway was activated by CRH and inhibited by SRIF. We provide evidence that cAMP/PKA signalling is involved affecting the GSK-3β phosphorylation status at phospho-GSK-3β (Ser9), thereby altering β-catenin degradation downstream. Furthermore, CRH and SRIF showed concordant effects on cell proliferation. Our data demonstrate an important role of the Wnt/β-catenin pathway in the proliferative control of pituitary corticotroph cells and describe a mechanism for its regulation by CRH and SRIF.

Immunohistochemical study of β-catenin and functionally related molecular markers in tongue squamous cell carcinoma and its correlation with cellular proliferation

β-catenin plays an important role in the maintenance of cell adhesion and is a key component of the Wnt signaling pathway. However, little is known about its prognostic significance or its role in tumor progression in tongue squamous cell carcinoma (SCC). This study conducted an immunohistochemical analysis of the expression of β-catenin. Moreover, its possible correlation with clinical parameters and with the expression of the functionally related molecular markers cyclin D1 and p53 was evaluated in 50 cases of tongue SCC and 10 cases of normal tongue epithelium. The ki-67 labeling index (LI) was also examined to evaluate cellular proliferation. Our results showed a higher frequency of abnormal β-catenin expression, positive cyclin D1 and p53 expression, and a significantly higher ki-67 LI in the tongue SCC samples compared with normal tongue epithelium (P<0.05). Abnormal β-catenin and a higher ki-67 expression was significantly associated with moderately or poorly differentiated carcinoma (P<0.05). Cyclin D1-positive immunostaining showed a statistically significant association with lymph node metastasis (P<0.05). Furthermore, the abnormal expression of β-catenin significantly correlated with a higher ki-67 LI and p53 expression (P<0.05); however, there was no correlation with cyclin D1 expression (P>0.05). Taken together, our results suggest that abnormal β-catenin expression is related to the impaired cellular differentiation and proliferation involved in tumor progression in tongue SCC.

Advances in pancreatic cancer detection

Pancreatic cancer represents a major challenge for research studies and clinical management. No specific tumor marker for the diagnosis of pancreatic cancer exists. Therefore, extensive genomic, transcriptomic, and proteomic studies are being developed to identify candidate markers for use in high-throughput systems capable of large cohort screening. Understandably, the complex pathophysiology of pancreatic cancer requires sensitive and specific biomarkers that can improve both early diagnosis and therapeutic monitoring. The lack of a single diagnostic marker makes it likely that only a panel of biomarkers is capable of providing the appropriate combination of high sensitivity and specificity. Biomarker discovery using novel technology can improve prognostic upgrading and pinpoint new molecular targets for innovative therapy.

Increased expression of beta-catenin, phosphorylated glycogen synthase kinase 3beta, cyclin D1, and c-myc in laterally spreading colorectal tumors

Laterally spreading tumors (LSTs) are considered a special subtype of superficial colorectal tumor. This study was performed to characterize the clinicopathological features and examine activation of the Wnt/beta-catenin pathway in LSTs and protruded-type colorectal adenomas (PAs). Fifty LSTs and 54 PAs were collected, and their clinicopathological characteristics were compared. The expression of E-cadherin, beta-catenin, glycogen synthase kinase-3beta (GSK-3beta), phosphorylated GSK-3beta, (phospho-GSK-3beta), cyclin D1, and c-myc was investigated by immunohistochemical staining on serial sections. Patients with LSTs were significantly older than those bearing PAs (63.4 vs 47.4 years old; p<0.001). The mean size of LSTs was significantly larger than that of PAs (27.0 mm vs 14.6 mm; p<0.01). Forty-eight percent of LSTs were located in the proximal colon, which was significantly higher than that of PAs (18.5%; p<0.05). Expression of beta-catenin, phospho-GSK-3beta, cyclin D1, and c-myc was significantly increased in LSTs compared with PAs (p<0.05). However, E-cadherin and total GSK-3beta expression was not significantly different between the two groups. The level of beta-catenin expression correlated strongly with phospho-GSK-3beta, cyclin D1, and c-myc expression in LSTs but not in PAs. Our findings suggest that activation of the Wnt/beta-catenin pathway is more prevalent in LSTs than in PAs, suggesting that phosphorylation-dependent inactivation of GSK-3beta may be involved in LST carcinogenesis.

Decreased expression of CXXC4 promotes a malignant phenotype in renal cell carcinoma by activating Wnt signaling

The Wnt signaling pathway is involved in normal embryonic development and controls the homeostatic self-renewal of stem cells in adult tissues. Constitutive activation of Wnt signaling contributes to cancer development and progression. We identified a CXXC4 homozygous deletion at 4q24 in an aggressive renal cell carcinoma (RCC) using single-nucleotide polymorphism (SNP) arrays. CXXC4 encodes Idax, which negatively regulates Wnt signaling by binding to the PDZ domain of Dishevelled. CXXC4 mRNA levels in tumor samples were significantly lower in patients with metastases compared with those without (P=0.0016). Patients whose tumors had lower CXXC4 expression than normal kidney showed a poorer cause-specific survival outcome than those with higher expression (P=0.0095). Decreased expression of CXXC4 also correlated with cytoplasmic staining of beta-catenin. Knockdown of CXXC4 induced the nuclear translocation of beta-catenin and altered expression of a set of genes involved in cell proliferation, invasion and survival. Furthermore, reduced expression of CXXC4 by small interfering RNAs promoted cell proliferation and inhibited apoptosis after 5-FU and doxorubicin treatment in RCC cells. These data suggest that CXXC4 plays a critical role in tumor progression of RCC through Wnt signaling. Wnt signaling could thus be a potential molecular target in RCC indicating decreased CXXC4 expression.

Dishevelled family proteins are expressed in non-small cell lung cancer and function differentially on tumor progression

BACKGROUND

Dishevelled (Dvl) family proteins are cytoplasmic mediators of the Wnt/beta-catenin signaling pathway and have recently been linked to cancers. However, the roles of individual Dvls and their expression in human cancers are poorly defined. This work aimed to characterize the expression of Dvls and their correlation to clinicopathological factors and beta-catenin expression in non-small cell lung cancer (NSCLC).

METHODS

We used immunohistochemistry to assess the presence of the three Dvl family proteins in 113 individual NSCLC specimens. Thirty-nine of the 113 cases were examined further for Dvl and beta-catenin protein expression in matched primary growths and autologous nodal metastases. We also examined the effect of Dvl-1 and Dvl-3 overexpression on beta-catenin expression and the invasive ability of A549 and QG56 lung cancer cells.

RESULTS

The positive expression rate in primary tumors was 53.1% (60/113) for total Dvl, 36.3% (41/113) for Dvl-1, 36.3% (41/113) for Dvl-2 and 41.6% (47/113) for Dvl-3, while normal adult bronchial and alveolar epithelia showed negative expression of all these proteins. The expression levels of all three Dvl proteins were significantly higher in adenocarcinomas than in squamous carcinomas, and were associated with poor tumor differentiation. The positive expression of Dvl-1 and Dvl-2 proteins was correlated to advanced pTNM stages (III-IV vs. I-II). In addition, the expression levels of Dvl-1 and Dvl-3 were significantly higher in nodal metastases than in primary growths, with the Dvl-1 expression correlating to beta-catenin expression in the metastases. Exogenous expression of Dvl-1 and Dvl-3 both enhanced the invasive ability of A549 and QG56 cells, but had differential effects on beta-catenin protein expression in either cell line, without influencing beta-catenin mRNA levels.

CONCLUSIONS

Expression of Dvl family proteins, Dvl-1, Dvl-2 and Dvl-3, is common in NSCLCs. They may contribute to the progression of NSCLCs, but Dvl-1 and Dvl-3 may function on this process through different signaling pathways.

Targeting of extracellular proteases required for the progression of pancreatic cancer

BACKGROUND

Pancreatic ductal adenocarcinoma (PDA) is the fourth leading cause of cancer-related death in the United States. Its lethality is due, in large part, to its resistance to traditional chemotherapeutics. As a result, there is an enormous effort being put into basic research to identify proteins that are required for PDA progression so that they may be specifically targeted for therapy.

OBJECTIVE

To compile and analyze the evidence that suggests that extracellular proteases are significant contributors to PDA progression.

METHODS

We focus on three different extracellular protease subclasses expressed in PDA: metalloproteases, serine proteases and cathepsins. Based on data from PDA and other cancers, we suggest their probable roles in PDA.

RESULTS/CONCLUSIONS

Of the proteases expressed in PDA, many appear to have overlapping functions, based on the substrates they process, making therapeutics complicated. Two protease families most likely to have unique, critical functions during tumor progression, and therefore strong potential as therapeutic targets, are the a disintegrin and metalloproteases (ADAMs) and the cathepsins.

Immunohistochemical expression of cell-cycle proteins in gastric precancerous lesions

BACKGROUND

The early indicator for the subject predisposed to gastric cancer is abnormal proliferation of gastric epithelial cells, such as atrophic gastritis (AG), intestinal metaplasia (IM), and dysplasia, which have been considered as precancerous lesions of gastric cancer. To determine whether p53 protein, cyclins D1, and D3, and p27(kip1) play a role in the carcinogenesis pathway of gastric cancer, we performed an immunohistochemical study of their expression in gastric precancerous lesions.

METHODS

A total of 1 45 endoscopic gastric biopsy specimens of AG, IM, and gastric dysplasia were studied. These molecular markers were localized by immunohistochemistry.

RESULTS

P53 was expressed in 15% of cases with gastric dysplasia and not in the pre-dysplastic stages of the gastric mucosa. All cases were concerning high-grade dysplasia. Cyclin D1 protein was almost undetectable in the precancerous lesions of gastric cancer. Cyclin D3 protein overexpression was seen in 10% of biopsies with IM, and 50% of biopsies with gastric dysplasia. High expression of p27(kip1) protein was demonstrated in all cases of chronic gastritis. As atrophy, IM, and dysplasia develop, expression of p27(kip1) protein is suppressed. In total, 15% of dysplastic cases showed no expression of p27(kip1) protein.

CONCLUSIONS

(i) P53 mutation must be a late event during the development of gastric cancer. (ii) Cyclin D1 protein overexpression may not play a role in the progression from normal to neoplastic gastric mucosa, while overexpression of cyclin D3 is an earlier event during gastric carcinogenesis, and its role must be further evaluated. (iii) Reduced expression of p27(kip1) is a rather early event in gastric tumorigenesis, before dysplastic changes occur.

beta-Catenin nuclear accumulation in head and neck mucoepidermoid carcinoma: its role in cyclin D1 overexpression and tumor progression

BACKGROUND

Nuclear/cytoplasmic accumulation of beta-catenin is mainly regulated by its degradation, which is initiated by interaction with adenomatous polyposis coli (APC) protein. Accumulation of beta-catenin activates the transcription of 1 of the target oncogenic genes, cyclin D1, in the Wnt/Wingless pathway. The role of beta-catenin and cyclin D1 in this pathway has not been previously studied in head and neck mucoepidermoid carcinoma (MEC). This study investigates abnormalities of beta-catenin and the APC gene in MEC and correlates the patterns of cyclin D1 overexpression and nuclear/cytoplasmic accumulation of beta-catenin with the clinical outcome.

METHODS

Mutations of the beta-catenin and APC genes, as well as overexpression of cyclin D1, were investigated by polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) in tissue samples from 44 cases of MEC. In addition, we employed differential PCR method to detect amplification of the cyclin D1 gene. Furthermore, the overexpression of cyclin D1 and nuclear/cytoplasmic accumulation of beta-catenin was examined by immunohistochemistry, and any correlation with clinicopathologic parameters was evaluated.

RESULTS

Nuclear/cytoplasmic accumulation of beta-catenin was observed in 6 of 44 MEC cases (13.6%), 5 of which were high-grade MEC, while the other 1 case was intermediate-grade tumor. Mutational analysis of exon 3 of the beta-catenin gene revealed that 4 of 26 cases (15.4%) contained point mutations (3 in codon 32, GAC [Asp] to GGC [Gly]; 1 in codon 42, ACA [Thr] to ATA [Ile]), and all these 4 cases showed beta-catenin accumulation immunohistochemically. The nuclear/cytoplasmic accumulation of beta-catenin was significantly correlated with the adverse outcome of patients (p = .011). Two APC gene alterations were detected in 2 cases of low-grade MEC, where there was no beta-catenin nuclear accumulation. Amplification of the cyclin D1 gene was observed in 10 of 26 cases (38.5%). Cyclin D1 overexpression was recognized in 19 of 44 cases (43.2%) and was significantly correlated with beta-catenin accumulation (p = .003).

CONCLUSIONS

These findings suggest that beta-catenin, which, in cooperation with cyclin D1, plays crucial role in the Wnt-signaling pathway, may also contribute to the adverse outcome and high-grade tumor staging of MEC.

Altered expression of desmocollin 3, desmoglein 3, and beta-catenin in oral squamous cell carcinoma: correlation with lymph node metastasis and cell proliferation

Desmocollin 3 (Dsc3) and desmoglein 3 (Dsg3) are both transmembrane glycoproteins that belong to the cadherin family of calcium-dependent cell adhesion molecules. beta-Catenin is a member of the cadherin-catenin complex that mediates homotypic cell-cell adhesion and is also an important molecule in the wnt signaling pathway. In this study, we examined the simultaneous expression level of Dsc3, Dsg3, and beta-catenin in oral squamous cell carcinomas (OSCCs) and normal oral epithelia using immunohistochemistry. There was a significant correlation (p < 0.05) among the following variables in OSCCs: reduced or loss of expression of Dsc3, Dsg3, and beta-catenin compared to normal oral epithelium, reduced or loss of expression of Dsc3 and histological grade (moderately or poorly differentiated), and reduced or loss of expression of beta-catenin and lymph node metastasis. Furthermore, a positive correlation was found between reduced or loss of beta-catenin staining and reduced or loss of Dsc3 staining in lymph node metastatic cancer tissue (r = 0.734, p < 0.05). These results suggest an abnormal expression of Dsc3, Dsg3, and beta-catenin induced in the progression of oral carcinomas and that the Dsc3 expression level might be related to the regulation of beta-catenin in lymph node metastasis and cell proliferation in OSCCs.

Differential Expressions of Cyclin D1 Associated with Better Prognosis of Cancers of Ampulla of Vater

BACKGROUND

Periampullary cancers, the incidence of which increases gradually with industrialization, still pose a significant challenge to clinicians and researchers. Specifically, the role of cell-cycle proteins and tumor suppressor genes in these cancers is not yet clear. Recent studies have revealed that genes and proteins related to cell cycle and apoptosis regulation may be involved in pancreatic carcinogenesis.

METHODS

Tissue samples were obtained from patients with periampullary cancers who underwent surgery at the National Taiwan University Hospital without receiving previous chemotherapy or radiation therapy. All periampullary cancer tissue samples were examined by a pathologist, who was unaware of the parameters to be investigated. A total of 68 patients with periampullary cancers (29 ampulla of Vater cancers (AVCs) and 39 pancreatic ductal cancers (PDCs), including various stages and histological subtypes, were enrolled. The relevant demographic and clinicopathological information was obtained from medical records.

RESULTS

Cell-cycle proteins, including p16, Rb, cyclin D1, p53, and E2F1, were analyzed by immunohistochemical staining. Here, significant differences were noted between AVCs and PDCs with regard to the expression of cyclin D1. This corresponded to a poor prognosis in PDCs (P < 0.05); AVCs, on the other hand, showed a relatively high survival rate. There is no obvious statistical difference between the 2 groups with regard to the expression of p16, Rb, p53, and E2F1. The study also revealed that cyclin D1 plays different roles in the carcinogenesis of AVCs and PDCs.

CONCLUSIONS

The expression of cyclin D1 is more often correlated with prognosis in AVCs than in PDCs, and may serve as a biomarker for the disease.

Apoptosis, proliferation and differentiation patterns are influenced by Zebularine and SAHA in pancreatic cancer models

OBJECTIVE

Pancreatic cancer continues to be an urgent clinical problem. We used the novel DNA methyltransferase inhibitor Zebularine and the histone deacetylase inhibitor SAHA to investigate the epigenetic influence on viability and differentiation of the pancreatic cancer cell lines YAP C, DAN G and Panc-89 in vitro and in vivo.

MATERIAL AND METHODS

Cell vitality, proliferation and expression of PDX-1, cytokeratin 7 and 20, chromogranin A, vimentin, bax and bcl-2 were determined on the protein and mRNA level in vitro and in a subcutaneous xenograft model.

RESULTS

A time- and dose-dependent increase of apoptosis, paralleled by decreased proliferation, was observed after incubation with single agents or a combination therapy with lower concentrations. This was associated with up-regulation of pro-apoptotic bax and a phenotypic stabilization by the enhanced expression of cytokeratin 7. In vivo, growth of xenografts was delayed with the most pronounced effect in Panc-89 after 1 week of daily intraperitoneal injections of Zebularine paralleled with CK7 up-regulation and down-regulation of dedifferentiation markers.

CONCLUSIONS

Epigenetic modulation via inhibition of DNA methyltransferase and histone deacetylase induces apoptosis in human pancreatic cancer cells in vitro and delays xenograft growth in vivo, which is associated with a morphological/molecular phenotypic stabilization. These compounds may therefore be suitable as adjunctive therapeutic agents in the treatment of pancreatic cancer.

Collagen type I induces disruption of E-cadherin-mediated cell-cell contacts and promotes proliferation of pancreatic carcinoma cells

Pancreatic cancer is characterized by its invasiveness, early metastasis, and the production of large amounts of extracellular matrix (ECM). We analyzed the influence of type I collagen and fibronectin on the regulation of cellular adhesion in pancreatic cancer cell lines to characterize the role of ECM proteins in the development of pancreatic cancer. We show that collagen type I is able to initiate a disruption of the E-cadherin adhesion complex in pancreatic carcinoma cells. This is due to the increased tyrosine phosphorylation of the complex protein beta-catenin, which correlates with collagen type I-dependent activation of the focal adhesion kinase and its association with the E-cadherin complex. The activation and recruitment of focal adhesion kinase to the E-cadherin complex depends on the interaction of type I collagen with beta1-containing integrins and an integrin-mediated activation of the cellular kinase Src. The disassembly of the E-cadherin adhesion complex correlates with the nuclear translocation of beta-catenin, which leads to an increasing expression of the beta-catenin-Lef/Tcf target genes, cyclin D1 and c-myc. In addition to that, cells grown on collagen type I show enhanced cell proliferation. We show that components of the ECM, produced by the tumor, contribute to invasiveness and metastasis by reducing E-cadherin-mediated cell-cell adhesion and enhance proliferation in pancreatic tumor cells.

Cyclin A and beta-catenin expression in actinic keratosis, Bowen's disease and invasive squamous cell carcinoma of the skin

BACKGROUND

Actinic keratosis (AK) has been defined as a precancerous lesion or an early phase in the evolution of squamous cell carcinoma (SCC) and histological changes seen in the individual cells of an AK are indistinguishable from those seen in SCC, which invade the dermis. Cyclin A is an increasingly utilized proliferation marker that has functions in both S phase (DNA replication) and initiation of mitosis, whereas alterations of beta-catenin, the molecule involved in cell-cell adhesion and in signalling transduction, could promote invasive and proliferative capacities of malignant tumours.

OBJECTIVES

To determine cyclin A and beta-catenin expression pattern in cutaneous SCC and in in situ lesions classified as keratinocytic intraepidermal neoplasia (KIN) and, using traditional terms, as AK and Bowen's disease (BD), and to analyse it in relation to SCC differentiation, diameter and thickness.

METHODS

Immunohistochemical staining was performed on 110 formalin-fixed paraffin-embedded tissue samples with the streptavidin-biotin technique using antibodies to cyclin A and beta-catenin. On histological examination, 53 lesions were diagnosed as AK, 16 as BD and 41 as SCC-11 well differentiated (WD), 16 moderately differentiated (MD) and 14 poorly differentiated (PD). Using KIN classification, 22 lesions were KIN1, 23 were KIN2 and 24 were KIN3. For cyclin A, distribution and labelling index (LI), and for beta-catenin, level of membranous staining and presence of aberrant (nuclear/cytoplasmic) localization were examined.

RESULTS

Diffuse cyclin A presence was observed more frequently in BD than in AK (P < 0.0001) or SCC (P = 0.0002), and in SCC-PD compared with SCC-WD (P < 0.0001) or SCC-MD (P = 0.0003). Differences between KIN3 and KIN2, as well as KIN3 and KIN1 lesions, were statistically significant (P < 0.0001), and the same result appeared when KIN1 and KIN2 cases were grouped and compared with those of KIN3 (P < 0.0001). Cyclin A LI was significantly lower (P < 0.05) in AK than in BD or SCC, but no difference between BD and SCC was found, and LI in BD was even higher than in SCC-WD or SCC-MD, while analysis regarding SCC differentiation and KIN classification revealed the same correlation as for the cyclin A distribution. Reduced or absent beta-catenin membranous staining was found in 90 cases (81.8%), more often in SCC than in AK (P = 0.03) or in AK and BD grouped together (P = 0.02). There was no statistical difference between SCCs of various level of differentiation, or between different KIN grades. Diffuse loss of membranous beta-catenin staining showed 36 lesions (32.7%), more frequently SCC than AK (P = 0.003) or AK and BD grouped (P = 0.006), as well as SCC-PD compared with SCC-WD (P = 0.01) and SCC-MD (P = 0.03), whereas all KIN comparisons remained nonsignificant. Aberrant beta-catenin cellular localization demonstrated 28 lesions (25.5%), most often in the basal or peripheral parts and in the lesions with diffuse beta-catenin loss (P = 0.009), but revealed no correlation with the histological type, SCC level of differentiation or KIN grades. Diffuse loss of membranous beta-catenin staining was found to be significantly more frequent in SCC thicker than 4 mm (P = 0.03), while all other comparisons between cyclin A or beta-catenin with the tumour size remained nonsignificant. Cyclin A LI was higher in cases with diffuse loss of membranous staining (P = 0.001) or with aberrant cellular localization of beta-catenin (P = 0.002).

CONCLUSIONS

Cyclin A LI showed greater difference between AK and BD than between BD and SCC, suggesting that increased proliferation (measured by cyclin A LI) characterizes progression of in situ lesions from AK to BD, whereas reduced beta-catenin expression separates more clearly SCC from the in situ lesions. Diffuse pattern of loss of membranous beta-catenin staining correlated better with the type of lesion, SCC differentiation and tumour size than reduced expression in general or aberrant cellular localization of beta-catenin. KIN classification does not seem to be supported by our findings, except when KIN1 and KIN2 lesions (in situ, partial thickness) are grouped.

[Undifferentiated pancreatic carcinomas. Leap into chaos]

Undifferentiated pancreatic carcinomas are rare anaplastic variants of ductal adenocarcinoma of the pancreas. They have to be distinguished immunohistochemically from metastases of malignant melanoma or an infiltrating sarcoma. An uncommon variant is undifferentiated pancreatic carcinoma with osteoclast-like giant cells. This variant can be associated with mucinous cystic neoplasms and is characterized by abundant non-neoplastic osteoclast-like giant cells.

Molecular prognostic markers in pancreatic cancer: a systematic review

Pancreatic cancer is one of the most lethal tumours of the gastrointestinal tract. The ability to predict which patients would benefit most from surgical intervention and/or chemotherapy would be a great clinical asset. Considerable research has focused on identifying molecular events in pancreatic carcinogenesis, and their correlation with clinicopathological variables of pancreatic tumours and survival. This systematic review examined evidence from published manuscripts looking at molecular markers in pancreatic cancer and their correlation with tumour stage and grade, response to chemotherapy and long-term survival. A literature search was undertaken using PubMed and MEDLINE search engines, using the keywords p53, p21, p16, p27, SMAD4, K-ras, cyclin D1, Bax, Bcl-2, EGFR, EGF, c-erbB2, HB-EGF, TGFbeta, FGF, MMP, uPA, cathepsin, heparanase, E-cadherin, laminins, integrins, TMSF, CD44, cytokines, angiogenesis, VEGF, IL-8, beta-catenin, DNA microarray, and gene profiling. A bewildering number of biomarkers are currently under evaluation. For the most part, the evidence regarding their application as prognostic indicators is conflicting. The advent of gene microarray and mass spectrometric protein profiling offers the potential to examine many different biomarkers simultaneously. This 'protein/gene signature' could revolutionise work in this field and allow researchers to develop accurate and reproducible predictions of survival based on protein or gene profiles.

The Wnt pathway is active in a small subset of pancreas cancer cell lines

Activation of the Wnt pathway plays an important role in the development of a wide variety of tumor types. Two genes involved in the activation of this pathway in tumors are Adenomatous Polyposis Coli (APC) and beta-catenin. Here, we analyze the activity of the Wnt pathway in cultured cells derived from ductal and acinar pancreatic adenocarcinomas using a reporter assay dependent on the activity of the beta-catenin/Tcf4 complex. We find that low-level Wnt activity can be detected in several pancreas cancer lines. High levels of reporter activity were detected exclusively in RWP-1 cells. These cells display nuclear beta-catenin and express a truncated APC protein resulting from a CAA>TAA mutation (Q1303X). Expression of a dominant negative Tcf4 protein inhibited proliferation of RWP-1 cells but not in other lines lacking beta-catenin-dependent reporter activity, supporting the functional relevance of this mutation. Our findings indicate that activation of the Wnt pathway may play a role in a small subset of ductal pancreatic cancers. Alternatively, RWP-1 cells may have been derived from a tumor arising in a structure adjacent to the pancreas such as the biliary tract or the Ampulla of Vater. Additional studies on the role of Wnt pathway components in the development/progression of tumors of the peripancreatic region merit consideration.

Different capabilities of morphological pattern formation and its association with the expression of differentiation markers in a xenograft model of human pancreatic cancer cell lines

AIMS

New concepts of tumorigenesis favor an unregulated process recapitulating different stages of embryogenic development with dysregulation of transition states. The aim of our study was to investigate the possibility of differentiation pathways of human pancreatic cancer cell lines in vivo.

MATERIAL AND METHODS

Different human pancreatic cancer cell lines (YAPC, DAN-G, CAPAN-1, PANC-1 and MIA PaCa-2) were implanted subcutaneously (3 x 10(6) cells) for 28 days in nude mice. Xenotransplants were characterized with histochemistry (HE, PAS), immunohistochemistry (cytokeratin (CK)7, CK8, CK18, CK19, CK20, vimentin, chromogranin A (Chr-A), alpha1-antichymotrypsin (alpha1-chym), beta-catenin, laminin-5, pancreatic and duodenal homeobox gene 1 (pdx-1), sonic hedgehog protein (shh), Patched (ptc)), Western blotting and real-time PCR (CK7, CK8, CK20, Chr-A, pdx-1, shh, ptc).

RESULTS

Depending on three major morphologic phenotypes of tumor cell xenotransplants (ductal (YAPC), ductal/solid (DAN-G, CAPAN-1), solid (PANC-1, MIA PaCa-2)), a decrease of CK7/CK19 was found, accompanied by an increase of CK8/18 and vimentin. Predominantly the CK7-positive ductal phenotype (YAPC and DAN-G) was associated with pdx-1 expression, whereas the CK8-positive solid phenotype was associated with shh/ptc expression on protein and mRNA level. Additionally, CK-20 expression was mainly linked to the ductal phenotype, co-localized with nuclear beta-catenin. The endocrine-exocrine transdifferentiation, as assessed by Chr-A and alpha1-chym, was on a constant low to moderate level in all xenotransplants. Finally, an intensive epithelial-mesenchymal interaction was observed by overexpression of laminin-5 at the invasion front.

CONCLUSION

The observed patterns of morphology and molecular differentiation in human pancreatic cancer xenografts indicate that these cancer cell lines have different capabilities of pattern formation in vivo associated with molecular differentiation markers, especially of embryonic pancreatic development.

Alteration of frizzled expression in renal cell carcinoma

To evaluate the involvement of frizzled receptors (Fzds) in oncogenesis, we investigated mRNA expression levels of several human Fzds in more than 30 different human tumor samples and their corresponding (matched) normal tissue samples, using real-time quantitative PCR. We observed that the mRNA level of Fzd5 was markedly increased in 8 of 11 renal carcinoma samples whilst Fzd8 mRNA was increased in 7 of 11 renal carcinoma samples. Western blot analysis of crude membrane fractions revealed that Fzd5 protein expression in the matched tumor/normal kidney samples correlated with the observed mRNA level. Wnt/beta-catenin signaling pathway activation was confirmed by the increased expression of a set of target genes. Using a kidney tumor tissue array, Fzd5 protein expression was investigated in a broader panel of kidney tumor samples. Fzd5 membrane staining was detected in 30% of clear cell carcinomas, and there was a strong correlation with nuclear cyclin D1 staining in the samples. Our data suggested that altered expression of certain members of the Fzd family, and their downstream targets, could provide alternative mechanisms leading to activation of the Wnt signaling pathway in renal carcinogenesis. Fzd family members may have a role as a biomarker.

β-catenin up-regulates the expression of cyclinD1, c-myc and MMP-7 in human pancreatic cancer: Relationships with carcinogenesis and metastasis

AIM: To investigate whether abnormal expression of β-catenin in conjunction with overexpression of cyclinD1, c-myc and matrix metalloproteinase-7 (MMP-7) correlated with the carcinogenesis, metastasis and prognosis of pancreatic cancer, and to analyze the relationship of β-catenin expression with cyclinD1, c-myc and MMP-7 expression.

METHODS: Using immunohistochemistry, we examined the expression of β-catenin, cyclinD1, c-myc and MMP-7 in 47 pancreatic adenocarcinoma tissues, 12 pancreatic intraepithelial neoplasia (PanIN) and 10 normal pancreases, respectively. Proliferation cell nuclear antigen was also tested as the index of proliferative activity of pancreatic cancer cells.

RESULTS: In 10 cases of normal pancreatic tissues, epithelial cells showed equally strong membranous expression of β-catenin protein at the cell-cell boundaries, but the expression of cyclinD1, c-myc and MMP-7 was negative. The expression of β-catenin, cyclinD1, c-myc and MMP-7 in PanIN and pancreatic adenocarcinoma tissues had no significant difference [6/12 and 32/47 (68.1%), 6/12 and 35/47 (74.5%), 5/12 and 33/47 (70.2%), 7/12 and 30/47 (63.8%), respectively]. The abnormal expression of β-catenin was significantly correlated to metastasis and one-year survival rate of pancreatic cancer, but had no relation with size, differentiation and cell proliferation. The expression of cyclinD1 was correlated with cell proliferation and extent of differentiation, but not with size, metastasis and one-year survival rate of the pancreatic cancer. The expression of c-myc was not correlated with size, extent of differentiation, metastasis and 1-year survival rate, but closely with cell proliferation of pancreatic cancer. The overexpression of MMP-7 was significantly associated with metastasis and 1-year survival rate of pancreatic cancer, but not with size, extent of differentiation and cell proliferation. There was a highly significant positive association between abnormal expression of β-catenin and overexpression of cyclinD1, c-myc and MMP-7 not only in PanIN (r = 1.000, 0.845, 0.845), but also in pancreatic cancer (r = 0.437, 0.452, 0.435).

CONCLUSION: The abnormal expression of β-catenin plays a key role in the carcinogenesis and progression of human pancreatic carcinoma by up-regulating the expression of cyclinD1, c-myc and MMP-7, resulting in the degradation of extracellular matrix and uncontrolled cell proliferation and differentiation. β-catenin abnormal expression and MMP-7 overexpression may be considered as two useful markers for determining metastasis and prognosis of human pancreatic cancer.

Changes in the Wnt signalling pathway in gastrointestinal cancers and their prognostic significance

Many steps in the Wnt signalling pathway may be altered during the process of carcinogenesis. This Review focuses on the changes observed in gastrointestinal cancers. A literature search was undertaken and the currently available data summarised. Understanding the alterations to this signalling pathway may help to reveal future targets for therapeutic agents. In addition, since in some tumours, levels of components of the Wnt pathway have been found to correlate with clinical stage, their potential use as prognostic indicators is highlighted.

Up-regulation of Wnt-1 and beta-catenin production in patients with advanced metastatic prostate carcinoma: potential pathogenetic and prognostic implications

BACKGROUND

Wnt-1 and beta-catenin expression levels play an important role in several malignancies. The authors determined the level of production of Wnt-1 and beta-catenin in normal and malignant human prostate carcinoma cell lines. Surgical pathology specimens from primary prostatic adenocarcinoma, lymph node metastases, and skeletal metastases were used to establish a correlation between the level of Wnt-1/beta-catenin expression, Gleason score, serum prostate-specific antigen (PSA) status, and androgen receptor (AR) status.

METHODS

Immunohistochemical analysis was used to investigate the expression of Wnt-1 and beta-catenin in human prostate carcinoma cell lines and in paraffin embedded sections of archival samples from 67 patients with prostate carcinoma. Comparison was made with the expression of tumoral AR and lymph node and skeletal metastases. These results were used to establish a correlation with the clinicopathologic status of patients with prostate carcinoma.

RESULTS

Levels of both Wnt-1 and beta-catenin were low in normal prostate cells and were expressed highly in human prostate carcinoma cell lines. Wnt-1 and cytoplasmic/nuclear beta-catenin expression was observed in 52% and 34%, respectively, of primary prostate carcinoma specimens. High levels of expression of Wnt-1 and beta-catenin were seen in 77% of lymph node metastases and in 85% of skeletal metastases. These increased levels of expression were related directly to the Gleason score and to serum PSA levels in these patients. Maximum levels of Wnt-1 and beta-catenin production were observed in skeletal metastases, whereas normal prostatic tissue failed to exhibit any detectable nuclear staining for beta-catenin.

CONCLUSIONS

High levels of Wnt-1 and beta-catenin expression were associated with advanced, metastatic, hormone-refractory prostate carcinoma, in which they can serve as markers of disease progression.