beta-catenin regulates the expression of the matrix metalloproteinase-7 in human colorectal cancer

A point mutation in the extracellular domain of L1 blocks its capacity to confer metastasis in colon cancer cells via CD10

The neural L1 transmembrane cell adhesion receptor of the immunoglobulin-like family is a target gene of Wnt-β-catenin signaling in human colorectal cancer (CRC) cells and is expressed at the invasive edge of the tumor tissue. L1 overexpression in cultured CRC cells confers enhanced proliferation, motility and liver metastasis. We have analyzed the mechanisms of L1-mediated signaling in CRC cells by using various point mutations in the L1 ectodomain that are known to cause severe genetically inherited mental retardation disorders in patients. We found that all such L1 ectodomain mutations abolish the ability of L1 to confer metastatic properties in CRC cells. Using gene array analysis, we identified L1-mutation-specific gene expression signatures for the L1/H210Q and L1/D598N mutations. We identified CD10, a metalloprotease (neprilysin, neutral endopeptidase) and a gene that is specifically induced in CRC cells by L1 in an L1/H210Q mutation-specific manner. CD10 expression was required for the L1-mediated induction of cell proliferation, motility and metastasis, as suppression of CD10 levels in L1-expressing CRC cells abolished the L1 effects on CRC progression. The signaling from L1 to CD10 was mediated through the L1-ezrin-NF-κB pathway. In human CRC tissue L1 and CD10 were localized in partially overlapping regions in the more invasive areas of the tumor tissue. The results suggest that CD10 is a necessary component conferring the L1 effects in CRC cells. The identification of gene expression patterns of L1-domain-specific point mutations may provide novel markers and targets for interfering with L1-mediated CRC progression.

Nuclear expression of TCF4/TCF7L2 is correlated with poor prognosis in patients with esophageal squamous cell carcinoma

The prognosis for patients with esophageal cancer remains poor. Therefore, the identification of novel target molecules for the treatment of esophageal cancer is necessary. Here, we investigated the clinicopathological significance of transcription factor 4/transcription factor 7-like 2 (TCF4/TCF7L2) in resectable esophageal squamous cell carcinoma (ESCC), because TCF4/TCF7L2 expression has not been studied in esophageal cancer previously.

This study included 79 patients with esophageal cancer who underwent surgery between 1998 and 2005. The expression of the TCF4/TCF7L2 protein in the nucleus of esophageal cancer cells was analyzed using immunohistochemistry. We examined the correlation between TCF4/TCF7L2 expression, clinicopathological factors, and prognosis in patients with ESCC.

TCF4/TCF7L2 was expressed in 57 % (45/79) of patients. TCF4/TCF7L2 expression was correlated with T factor (T1 vs. T2-4, p = 0.001), stage (I vs. II-IV, p =0.0058), Ly factor (p =0.038), and V factor (p =0.038) and did not correlate with age, gender or N factor. Furthermore, patients who were positive for TCF4/TCF7L2 had a significantly lower survival rate than those who were negative for TCF4/TCF7L2 (log-rank test, p = 0.0040). TCF4/TCF7L2 expression significantly affected the survival of patients with ESCC. Positive expression of TCF4/TCF7L2 was correlated with a poor prognosis after a curative operation in patients with ESCC.

The receptor for advanced glycation end products is required for β-catenin stabilization in a chemical-induced asthma model

BACKGROUND AND PURPOSE

Cytoplasmic retention of β-catenin will lead to its nuclear translocation and subsequent interaction with the transcription factor TCF/LEF that regulates target gene expression. We have previously demonstrated aberrant expression of β-catenin in a model of asthma induced by toluene diisocyanate (TDI). The aim of this study was to examine whether the receptor for advanced glycation end products (RAGE) can regulate β-catenin expression in TDI-induced asthma.

EXPERIMENTAL APPROACH

Male BALB/c mice were sensitized and challenged with TDI to generate a chemically-induced asthma model. Inhibitors of RAGE, FPS-ZM1 and the RAGE antagonist peptide (RAP), were injected i.p. after each challenge. Airway resistance was measured in vivo and bronchoalveolar lavage fluid was analysed. Lungs were examined by histology and immunohistochemistry. Western blotting and quantitative PCR were also used.

KEY RESULTS

Expression of RAGE and of its ligands HMGB1, S100A12, S100B, HSP70 was increased in TDI-exposed lungs. These increases were inhibited by FPS-ZM1 or RAP. Either antagonist blunted airway reactivity, airway inflammation and goblet cell metaplasia, and decreased release of Th2 cytokines. TDI exposure decreased level of membrane β-catenin, phosphorylated Akt (Ser(473) ), inactivated GSK3β (Ser(9) ), dephosphorylated β-catenin at Ser(33) /(37) /Thr(41) , which controls its cytoplasmic degradation, increased phosphorylated β-catenin at Ser(552) , raised cytoplasmic and nuclear levels of β-catenin and up-regulated its targeted gene expression (MMP2, MMP7, MMP9, VEGF, cyclin D1, fibronectin), all of which were reversed by RAGE inhibition.

CONCLUSION AND IMPLICATIONS

RAGE was required for stabilization of β-catenin in TDI-induced asthma, identifying protective effects of RAGE blockade in this model.

WNT Signaling in Cutaneous Squamous Cell Carcinoma: A Future Treatment Strategy?

The molecular mechanisms underlying cutaneous squamous cell carcinoma are less well established than those for other common skin cancers, but recent evidence has highlighted a potentially critical role for WNT signaling in both the development and progression of cutaneous squamous cell carcinoma. WNT pathways are aberrantly regulated in multiple tumor types (albeit in a context-dependent manner), and this has stimulated the development of WNT inhibitory compounds for cancer treatment. In this review, we examine existing evidence for a role of WNT signaling in cutaneous squamous cell carcinoma and discuss if WNT inhibition represents a realistic therapeutic strategy for the future.

Expressions of TIMP-1, COX-2 and MMP-7 in Colon Polyp and Colon Cancer

Objective

We aimed to investigate the relationship of expression of matrix metalloproteinase-7 (MMP-7), tissue inhibitor of metalloproteinase-1 (TIMP-1) and cyclooxygenase-2 (COX-2) in colon cancer and its predecessor colon polyp.

Materials and methods

This study included 29 patients with colon polyp, 19 patients with colon cancer and 65 healthy control subjects. The expressions of MMP-7, TIMP-1 and COX-2 were investigated by real time-polymerase chain reaction (RT-PCR).

Results

The expressions of TIMP-1, COX-2 and MMP-7 levels were significantly higher in polyp tissue compared to normal tissue (p = 0.024, p < 0.001, p = 0.009, respectively). Expression of TIMP-1, COX-2 and MMP-7 in cancer tissues were higher than both normal tissue and polyp tissue (p = 0.009 and p = 0.001; p < 0.001 and p < 0.001; p = 0.029 and p = 0.008, respectively). In the cancer group, no significant relationship was detected between metastasis and MMP-7, TIMP-1 and COX-2 expressions (p > 0.05). In the polyp tissues, no significant relationship was detected between the histologic type and size of polyps and MMP-7, TIMP-1 and COX-2 levels (p > 0.05). The areas under the receiver operating characteristic (ROC) curve for the cancer group were 0.821 for TIMP-1, 0.888 for COX-2, and 0.880 for MMP-7 (p = 0 < 0.001).

Conclusion

A role and implication of expressions of MMP-7, COX-2 and TIMP-1 in colon cancer is predicted.

How to cite this article

Bengi G, Keles D, Topalak Ö, Yalçin M, Kiyak R, Oktay G. Expressions of TIMP-1, COX-2 and MMP-7 in Colon Polyp and Colon Cancer. Euroasian J Hepato-Gastroenterol 2015;5(2):74-79.

Macrophage TCF-4 co-activates p65 to potentiate chronic inflammation and insulin resistance in mice

Transcription factor 4 (TCF-4) was recently identified as a candidate gene for the cause of type 2 diabetes, although the mechanisms have not been fully elucidated. In the present study, we demonstrated that the TCF-4 transgene in macrophages aggravated high-fat diet (HFD)-induced insulin resistance and chronic inflammation, characterized by the elevation of proinflammatory cytokines in the blood, liver and white adipose tissue, as well as a proinflammatory profile of immune cells in visceral fats in mice. Mechanistically, TCF-4 functioned as a co-activator of p65 to amplify the saturated free fatty acid (FFA)-stimulated promoter activity, mRNA transcription and secretion of proinflammatory cytokines in primary macrophages. Blockage of p65 with a specific interfering RNA or inhibitor could prevent TCF-4-enhanced expression of proinflammatory cytokines in FFA/lipopolysaccharide-treated primary macrophages. The p65 inhibitor could abolish macrophage TCF-4 transgene-aggravated systemic inflammation, glucose intolerance and insulin resistance in HFD-treated mice. In addition, we demonstrated that the mRNA expression of TCF-4 in the peripheral blood monocytes from humans was positively correlated to the levels of interleukin (IL)-1β, tumour necrosis factor α, IL-6 and fasting plasma glucose. In summary, we identified TCF-4 as a co-activator of p65 in the potentiation of proinflammatory cytokine production in macrophages and aggravation of HFD-induced chronic inflammation and insulin resistance in mice.

Glucose induced activation of canonical Wnt signaling pathway in hepatocellular carcinoma is regulated by DKK4

Elevated glycemic index, an important feature of diabetes is implicated in an increased risk of hepatocellular carcinoma (HCC). However, the underlying molecular mechanisms of this association are relatively less explored. Present study investigates the effect of hyperglycemia over HCC proliferation. We observed that high glucose culture condition (HG) specifically activates canonical Wnt signaling in HCC cells, which is mediated by suppression of DKK4 (a Wnt antagonist) expression and enhanced β-catenin level. Functional assays demonstrated that a normoglycemic culture condition (NG) maintains constitutive expression of DKK4, which controls HCC proliferation rate by suppressing canonical Wnt signaling pathway. HG diminishes DKK4 expression leading to loss of check at G0/G1/S phases of the cell cycle thereby enhancing HCC proliferation, in a β-catenin dependent manner. Interestingly, in NOD/SCID mice supplemented with high glucose, HepG2 xenografted tumors grew rapidly in which elevated levels of β-catenin, c-Myc and decreased levels of DKK4 were detected. Knockdown of DKK4 by shRNA promotes proliferation of HCC cells in NG, which is suppressed by treating cells exogenously with recombinant DKK4 protein. Our in vitro and in vivo results indicate an important functional role of DKK4 in glucose facilitated HCC proliferation.

The Hippo pathway in intestinal regeneration and disease

The Hippo pathway is a signalling cascade conserved from Drosophila melanogaster to mammals. The mammalian core kinase components comprise MST1 and MST2, SAV1, LATS1 and LATS2 and MOB1A and MOB1B. The transcriptional co-activators YAP1 and TAZ are the downstream effectors of the Hippo pathway and regulate target gene expression. Hippo signalling has crucial roles in the control of organ size, tissue homeostasis and regeneration, and dysregulation of the Hippo pathway can lead to uncontrolled cell growth and malignant transformation. Mammalian intestine consists of a stem cell compartment as well as differentiated cells, and its ability to regenerate rapidly after injury makes it an excellent model system to study tissue homeostasis, regeneration and tumorigenesis. Several studies have established the important role of the Hippo pathway in these processes. In addition, crosstalk between Hippo and other signalling pathways provides tight, yet versatile, regulation of tissue homeostasis. In this Review, we summarize studies on the role of the Hippo pathway in the intestine on these physiological processes and the underlying mechanisms responsible, and discuss future research directions and potential therapeutic strategies targeting Hippo signalling in intestinal disease.

Matrix metalloproteinase (MMP) -2, -7 and -9 promoter polymorphisms in colorectal cancer in ethnic Kashmiri population - A case-control study and a mini review

Matrix metalloproteinases (MMPs) are proteolytic enzymes that play a pivotal role in the transformation and progression of tumors at all stages, especially during the invasion and metastasis. The aim of this study was to determine the genetic association of MMP2, MMP7 and MMP9 promoter polymorphisms with colorectal cancer (CRC) susceptibility and development risk in ethnic Kashmiri population. The genotype frequencies of MMP2-1306C/T, MMP7-181A/G and MMP9-1562C/T SNPs were compared between 142 CRC patients and 184 healthy controls by using PCR-RFLP method. The association between all the three MMP promoter polymorphisms and the modulation of risk of CRC was found to be significant (p≤0.05). The heterozygous genotype (CT) of MMP2-1306C/T SNP and variant genotype (GG) of MMP7-181A/G SNP showed a significant association with decreased risk for the development of CRC [OR, 0.61 (95%CI, 0.37-1.01); p=0.05 and OR, 0.43 (95%CI, 0.20-0.90); p=0.02, respectively] whereas the heterozygous genotype (CT) of MMP9-1562C/T SNP showed a significant association with increased risk for the development of colorectal cancer [OR, 1.88 (95%CI, 1.11-3.18); p=0.02]. Further, the less common MMP9-1562T allele was found to be significantly associated with an increased risk of colorectal cancer [OR, 1.74 (95%CI, 1.15-2.62); p=0.007]. Our results suggest that these MMP2, MMP7 and MMP9 promoter polymorphisms play a role as one of the key modulators of the risk of developing colorectal cancer in Kashmiri population.

Sporadic early-onset colon cancer expresses unique molecular features

BACKGROUND

The overall incidence of colon cancer (CC) has steadily declined in the last decades but has increased in patients under age 50 y. The etiology of early-onset (EO) CC is not understood. The aim of this study was to elucidate gene expression patterns in EOCC and show its uniqueness compared to late-onset (LO) disease.

METHODS

Two cohorts of patients with sporadic CC were identified. Tumors and matching noninvolved tissues from six EOCC patients (<50) and six late-onset colon cancers (LOCC) patients (>65) were obtained from pathology archives. De-paraffinized tissues were macrodissected from FFPE sections, RNA isolated, and used for expression profiling of 770 cancer-related genes representing 13 canonical pathways.

RESULTS

Among 770 genes assayed, changes in expression levels of 93 genes were statistically significant between EOCC and matching noninvolved tissues. There were also significant differences in expression levels of 118 genes between LOCC and matching noninvolved tissues. Detailed comparative gene expression analysis between EOCC and LOCC normalized to their matching noninvolved tissues revealed that changes in expression of 88 genes were unique to EOCC using the cutoff criteria of expression levels difference >2 fold and P value <0.01. From these differentially expressed genes specific to EOCC, 28 genes were upregulated and 60 genes downregulated. At the pathway level, RAS, MAPK, WNT, and DNARepair pathways were similarly deregulated in both age groups, whereas PI3K-AKT signaling was more specific to EOCC and cell cycle pathway to LOCC.

CONCLUSIONS

These results suggest that sporadic EOCC is characterized by distinct molecular events compared to LOCC.

MSK1-Mediated β-Catenin Phosphorylation Confers Resistance to PI3K/mTOR Inhibitors in Glioblastoma

Glioblastoma (GBM) represents a compelling disease for kinase inhibitor therapy because most of these tumors harbor genetic alterations that result in aberrant activation of growth factor-signaling pathways. The PI3K/mammalian target of the rapamycin (mTOR) pathway is dysregulated in over 50% of human GBM but remains a challenging clinical target. Inhibitors against PI3K/mTOR mediators have limited clinical efficacy as single agents. We investigated potential bypass mechanisms to PI3K/mTOR inhibition using gene expression profiling before and after PI3K inhibitor treatment by Affymetrix microarrays. Mitogen- and stress-activated protein kinase 1 (MSK1) was markedly induced after PI3K/mTOR inhibitor treatment and disruption of MSK1 by specific shRNAs attenuated resistance to PI3K/mTOR inhibitors in glioma-initiating cells (GIC). Further investigation showed that MSK1 phosphorylates β-catenin and regulates its nuclear translocation and transcriptional activity. The depletion of β-catenin potentiated PI3K/mTOR inhibitor-induced cytotoxicity and the inhibition of MSK1 synergized with PI3K/mTOR inhibitors to extend survival in an intracranial animal model and decreased phosphorylation of β-catenin at Ser(552) These observations suggest that MSK1/β-catenin signaling serves as an escape survival signal upon PI3K/mTOR inhibition and provides a strong rationale for the combined use of PI3K/mTOR and MSK1/β-catenin inhibition to induce lethal growth inhibition in human GBM. Mol Cancer Ther; 15(7); 1656-68. ©2016 AACR.

LMX1A inhibits metastasis of gastric cancer cells through negative regulation of β-catenin

Previously, we reported that the LIM homeobox transcription factor 1, alpha (LMX1A) presented tumor-suppressing roles in gastric AGS cells. Here, we showed that LMX1A also inhibits metastasis-related behaviors including migration and invasion of gastric cancer cells. Mechanistic study revealed that the role of LMX1A was mediated by β-catenin, as knockdown of LMX1A upregulated the expression of β-catenin and knockdown of β-catenin reversed the effects of LMX1A silencing. β-catenin is essential for the activation of WNT signaling pathway. Indeed, knockdown of LMX1A activated the expressions of WNT signaling target genes T cell-specific transcription factor 4 (TCF4) and matrix metalloproteinase-7 (MMP7). What is more, the expression of LMX1A was negatively correlated with WNT signaling target genes in two datasets of human gastric cancer tissues. Thus, our study revealed an anti-metastatic role of LMX1A in gastric cancer which is mediated by the negative regulation of β-catenin signaling target genes.

T cell factor-4 functions as a co-activator to promote NF-κB-dependent MMP-15 expression in lung carcinoma cells

Both TCF-4 and MMP-15 are closely linked to the development of lung cancer, while the regulatory role of TCF-4 in MMP-15 expression is still obscure. Here we found that expression of TCF-4 and MMP-15 was increased in lung cancer cells or tissues versus the normal ones. With gain-or loss-of -function studies, we demonstrated that TCF-4 positively regulated MMP-15 expression in mRNA and protein levels. With reporter gene assay, we found that TCF-4 regulated MMP-15 expression via a potential NF-κB binding element locating at -2833/-2824 in the mouse MMP-15 promoter. With ChIP and immunoblotting assays, we identified that TCF-4 functioned as a co-activator to potentiate the binding between p65 and MMP-15 promoter. Functionally, TCF-4 silence attenuated the migration activity of LLC cells, while additional overexpression of MMP-15 rescued this effect in cell scratch test and transwell migration assay. In xenograft model, TCF-4 silence-improved tumor lesions in lungs and survival time of LLC-tumor bearing mice were abolished by MMP-15 overexpression. In conclusion, we are the first to identify TCF-4 as a co-activator of NF-κB p65 to promote MMP-15 transcription and potentiate the migration activity of the lung cancer cells. Our findings shed light on the therapeutic strategies of this malignancy.

The anthelmintic niclosamide inhibits colorectal cancer cell lines via modulation of the canonical and noncanonical Wnt signaling pathway

BACKGROUND

Wnt/β-catenin signaling is known to play an important role in colorectal cancer (CRC). Niclosamide, a salicylamide derivative used in the treatment of tapeworm infections, targets the Wnt/β-catenin pathway. The objective of this study was to investigate niclosamide as a therapeutic agent against CRC.

METHODS

The antiproliferative effects of 1, 3, 10, and 50 μM concentrations of niclosamide on human (SW480 and SW620) and rodent (CC531) CRC cell lines were determined by MTS assay and direct cell count. The lymphoid enhancer-binding factor 1/transcription factor (LEF/TCF) reporter assay monitored the activity of Wnt signaling. Immunofluorescence staining demonstrated the expression pattern of active β-catenin. Gene expression of canonical and noncanonical Wnt signaling components was analyzed using qRT-PCR. Western blot analysis was performed with antibodies detecting nuclear localization of β-catenin and c-jun.

RESULTS

Cell proliferation in CRC cell lines was blocked dose dependently after 12 and 24 h of incubation. The Wnt promoter activity of LEF/TCF significantly decreased with niclosamide concentrations of 10 and 50 μM after 12 h of incubation. Active β-catenin did not shift from the nuclear to the cytosolic pool. However, canonical target genes (met, MMP7, and cyclin D1) as well as the coactivating factor Bcl9 were downregulated, whereas the noncanonical key player c-jun was clearly activated.

CONCLUSIONS

Niclosamide treatment is associated with an inhibitory effect on CRC development and reduced Wnt activity. It may exert its effect by interfering with the nuclear β-catenin-Bcl9-LEF/TCF triple-complex and by upregulation of c-jun representing noncanonical Wnt/JNK signaling. Thus, our findings warrant further research into this substance as a treatment option for patients with advanced CRC.

Extracellular Matrix Metalloproteinase Inducer (EMMPRIN) promotes lung fibroblast proliferation, survival and differentiation to myofibroblasts

Background

Idiopathic pulmonary fibrosis (IPF) is a chronic progressively fatal disease. Extracellular Matrix Metalloproteinase Inducer (EMMPRIN) is a glycosylated transmembrane protein that induces the expression of some matrix metalloproteinase (MMP) in neighboring stromal cells through direct epithelial–stromal interactions. EMMPRIN is highly expressed in type II alveolar epithelial cells at the edges of the fibrotic areas in IPF lung sections. However, the exact role of EMMPRIN in IPF is unknown.

Methods

To determine if EMMPRIN contributes to lung fibroblast proliferation, resistance to apoptosis, and differentiation to myofibroblasts, normal Human lung fibroblasts (NHLF) transiently transfected with either EMMPRIN/GFP or GFP were treated with TGF- β1 from 0 to 10 ng/ml for 48 h and examined for cell proliferation (thymidine incorporation), apoptosis (FACS analysis and Cell Death Detection ELISA assay), cell migration (Modified Boyden chamber) and differentiation to myofibroblasts using Western blot for α–smooth actin of cell lysates. The effect of EMMPRIN inhibition on NHLF proliferation, apoptosis, migration and differentiation to myofibroblasts after TGF- β1 treatment was examined using EMMPRIN blocking antibody. We examined the mechanism by which EMMPRIN induces its effects on fibroblasts by studying the β-catenin/canonical Wnt signaling pathway using Wnt luciferase reporter assays and Western blot for total and phosphorylated β-catenin.

Results

Human lung fibroblasts overexpressing EMMPRIN had a significant increase in cell proliferation and migration compared to control fibroblasts. Furthermore, EMMPRIN promoted lung fibroblasts resistance to apoptosis. Lung fibroblasts overexpressing EMMPRIN showed a significantly increased expression of α- smooth muscle actin, a marker of differentiation to myofibroblasts compared to control cells. TGF-β1 increased the expression of EMMPRIN in lung fibroblasts in a dose-dependent manner. Attenuation of EMMPRIN expression with the use of an EMMPRIN blocking antibody markedly inhibited TGF-β1 induced proliferation, migration, and differentiation of fibroblasts to myofibroblasts. EMMPRIN overexpression in lung fibroblasts was found to induce an increase in TOPFLASH luciferase reporter activity when compared with control fibroblasts.

Conclusion

These findings indicate that TGF-β1 induces the release of EMMPRIN that activates β-catenin/canonical Wnt signaling pathway. EMMPRIN overexpression induces an anti-apoptotic and pro-fibrotic phenotype in lung fibroblasts that may contribute to the persistent fibro-proliferative state seen in IPF.

Alternative splicing within the Wnt signaling pathway: role in cancer development

BACKGROUND

The Wnt signaling cascade plays a fundamental role in embryonic development, adult tissue regeneration, homeostasis and stem cell maintenance. Abnormal Wnt signaling has been found to be prevalent in various human cancers. Also, a role of Wnt signaling in the regulation of alternative splicing of several cancer-related genes has been established. In addition, accumulating evidence suggests the existence of multiple splice isoforms of Wnt signaling cascade components, including Wnt ligands, receptors, components of the destruction complex and transcription activators/suppressors. The presence of multiple Wnt signaling-related isoforms may affect the functionality of the Wnt pathway, including its deregulation in cancer. As such, specific Wnt pathway isoform components may serve as therapeutic targets or as biomarkers for certain human cancers. Here, we review the role of alternative splicing of Wnt signaling components during the onset and progression of cancer.

CONCLUSIONS

Splice isoforms of components of the Wnt signaling pathway play distinct roles in cancer development. Isoforms of the same component may function in a tissue- and/or cancer-specific manner. Splice isoform expression analyses along with deregulated Wnt signaling pathway analyses may be of help to design efficient diagnostic and therapeutic strategies.

Matrix metalloproteinases as therapeutic targets for idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a restrictive lung disease that is associated with high morbidity and mortality. Current medical therapies are not fully effective at limiting mortality in patients with IPF, and new therapies are urgently needed. Matrix metalloproteinases (MMPs) are proteinases that, together, can degrade all components of the extracellular matrix and numerous nonmatrix proteins. MMPs and their inhibitors, tissue inhibitors of MMPs (TIMPs), have been implicated in the pathogenesis of IPF based upon the results of clinical studies reporting elevated levels of MMPs (including MMP-1, MMP-7, MMP-8, and MMP-9) in IPF blood and/or lung samples. Surprisingly, studies of gene-targeted mice in murine models of pulmonary fibrosis (PF) have demonstrated that most MMPs promote (rather than inhibit) the development of PF and have identified diverse mechanisms involved. These mechanisms include MMPs: (1) promoting epithelial-to-mesenchymal transition (MMP-3 and MMP-7); (2) increasing lung levels or activity of profibrotic mediators or reducing lung levels of antifibrotic mediators (MMP-3, MMP-7, and MMP-8); (3) promoting abnormal epithelial cell migration and other aberrant repair processes (MMP-3 and MMP-9); (4) inducing the switching of lung macrophage phenotypes from M1 to M2 types (MMP-10 and MMP-28); and (5) promoting fibrocyte migration (MMP-8). Two MMPs, MMP-13 and MMP-19, have antifibrotic activities in murine models of PF, and two MMPs, MMP-1 and MMP-10, have the potential to limit fibrotic responses to injury. Herein, we review what is known about the contributions of MMPs and TIMPs to the pathogenesis of IPF and discuss their potential as therapeutic targets for IPF.

Evaluation of the correlation of KAI1/CD82, CD44, MMP7 and β-catenin in the prediction of prognosis and metastasis in colorectal carcinoma

BACKGROUND

To investigate the relationship of KAI1/CD82, CD44, matrix metalloproteinase 7 (MMP7) and β-catenin, and examine its association with clinicopathological features, metastasis and prognosis in colorectal carcinoma (CRC).

METHODS

Immunohistochemical (IHC) analysis was used to detect the expression of KAI1/CD82, CD44, MMP7 and β-catenin in 174 archival surgical specimens of human CRC. Furthermore, clinicopathological features such as age, sex and so on were also collected retrospectively.

RESULTS

CD44, MMP7 and β-catenin expression was positively associated with distant metastasis, lymph node metastasis and tumor-node-metastasis (TNM) stage. However, decreased KAI1/CD82 expression correlated significantly with distant metastasis, lymph node metastasis and TNM stage. KAI1/CD82 expression showed a negative correlation with CD44, MMP7 and β-catenin. Furthermore, β-catenin expression showed a positive correlation with CD44 and MMP7. Multivariate logistic regression analysis showed that KAI1/CD82 and β-catenin expression were significantly associated with lymph node metastasis and KAI1/CD82 was significantly associated with distant metastasis. Kaplan-Meier analysis revealed that CD44, MMP7 and β-catenin expression was negatively correlated with overall survival (OS), while KAI1/CD82 expression was positively correlated with OS. Low KAI1/CD82 expression and high expression of CD44, MMP7 and β-catenin was associated with a poor prognosis in CRC. Multivariate Cox regression analysis indicated that the expression of KAI1/CD82, MMP7 and β-catenin were independent predictors of OS in CRC.

CONCLUSION

The expression of KAI1/CD82, CD44, MMP7 and β-catenin is related to tumor metastasis and prognosis in CRC. Combined detection of these factors may be of significant value in predicting the prognosis and metastasis in CRC patients.

Properties and Clinical Relevance of Speckle-Type POZ Protein in Human Colorectal Cancer

BACKGROUND

The aims of this study are to evaluate the effect of Speckle-type POZ protein (SPOP) in colorectal cancer (CRC) patients and explore its significance in the prognosis.

METHODS

We used immunohistochemistry to detect the expression of SPOP in CRC. Moreover, this result was further confirmed at the protein and messenger RNA (mRNA) level in paired CRC specimens and matched adjacent noncancerous colon tissues by Western blotting and real-time quantitative PCR (qRT-PCR), respectively. Furthermore, we evaluate the effects of SPOP on CRC cell proliferation and migration in vitro. The Kaplan-Meier method and log-rank test were employed to compare the overall survival between SPOP low expression group and SPOP high expression group. Correlation of survival with clinicopathologic parameters, including SPOP level, was investigated with multivariate analyses.

RESULTS

We confirmed frequent SPOP downregulation in both mRNA (P = 0.0286) and protein (P = 0.004) levels in CRC tissues as compared to matched adjacent nontumorous tissues. Besides, the downregulated SPOP expression in CRC tissues was significantly correlated to poor differentiation (P = 0.013), distant metastasis (P = 0.003), gross type (P < 0.001), and high TNM stage (P = 0.002). Kaplan-Meier survival analysis showed that low SPOP expression exhibited a significant correlation with poor prognosis for CRC patients. Overexpression of SPOP in CRC cell lines significantly suppressed cell proliferation, migration, and clone formation. In contrast, SPOP knockdown dramatically promoted cell proliferation, migration, and clone formation in vitro. In addition, overexpression of SPOP increased E-cadherin and suppressed vimentin in HCT116 cells and silencing of SPOP reversed all these biomarkers. Furthermore, SPOP significantly downregulated MMP2 and MMP7 protein levels in HCT116 cell lines.

CONCLUSION

Our results suggest that SPOP plays a pivotal role in colorectal cancer (CRC) through mesenchymal-epithelial transition and MMPs, and it may be a potential therapeutic target in colorectal cancer.

PEDF and its roles in physiological and pathological conditions: implication in diabetic and hypoxia-induced angiogenic diseases

Pigment epithelium-derived factor (PEDF) is a broadly expressed multifunctional member of the serine proteinase inhibitor (serpin) family. This widely studied protein plays critical roles in many physiological and pathophysiological processes, including neuroprotection, angiogenesis, fibrogenesis and inflammation. The present review summarizes the temporal and spatial distribution patterns of PEDF in a variety of developing and adult organs, and discusses its functions in maintaining physiological homoeostasis. The major focus of the present review is to discuss the implication of PEDF in diabetic and hypoxia-induced angiogenesis, and the pathways mediating PEDF's effects under these conditions. Furthermore, the regulatory mechanisms of PEDF expression, function and degradation are also reviewed. Finally, the therapeutic potential of PEDF as an anti-angiogenic drug is briefly summarized.

Role of MCP-1 in alcohol-induced aggressiveness of colorectal cancer cells

Epidemiological studies demonstrate that alcohol consumption is associated with an increased risk of colorectal cancer (CRC). In addition to promoting carcinogenesis, alcohol may also accelerate the progression of existing CRC. We hypothesized that alcohol may enhance the aggressiveness of CRC. In this study, we investigated the effect of alcohol on the migration/invasion and metastasis of CRC. Alcohol increased the migration/invasion of colorectal cancer cells (DLD1, HCT116, HT29, and SW480) in a concentration-dependent manner. Among these colon cancer cell lines, HCT116 cells were most responsive while HT29 cells were the least responsive to ethanol-stimulated cell migration/invasion. These in vitro results were supported by animal studies which demonstrated that ethanol enhanced the metastasis of colorectal cancer cells to the liver and lung. Monocyte chemoattractant protein-1 (MCP-1) is a chemokine that plays an important role in regulating tumor microenvironment and metastasis. Alcohol increased the expression of MCP-1 and its receptor CCR2 at both protein and mRNA levels. The pattern of alcohol-induced alterations in MCP-1 expression was consistent with its effect on migration/invasion; HCT116 cells displayed the highest up-regulation of MCP-1/CCR2 in response to alcohol exposure. An antagonist of CCR2 blocked alcohol-stimulated migration. Alcohol caused an initial cytosolic accumulation of β-catenin and its subsequent nuclear translocation by inhibiting GSK3β activity. Alcohol stimulated the activity of MCP-1 gene promoter in a β-catenin-dependent manner. Furthermore, knock-down of MCP-1/CCR2 or β-catenin was sufficient to inhibit alcohol-induced cell migration/invasion. Together, these results suggested that alcohol may promote the metastasis of CRC through modulating GSK3β/β-catenin/MCP-1 pathway.

Hypoxia-inducible factor-1α and Wnt/β-catenin signaling pathways promote the invasion of hypoxic gastric cancer cells

The present study aimed to examine the association between hypoxia-inducible factor (HIF)-1α and the Wnt/β-catenin signaling pathway in a hypoxic environment. The study also aimed to explore the possible mechanisms underlying the invasion of hypoxic gastric cancer cells in vitro and in vivo. The pcDNA™ 6.2‑GW/EmGFP‑miR‑β‑catenin plasmid was transfected into SGC‑7901 gastric cancer cells, resulting in cells with stable suppression of β‑catenin expression. The biological characteristics of the control, liposome, negative control, β‑catenin knockdown, hypoxia and hypoxia β‑catenin knockdown groups were tested using an invasion assay. The differences in the invasive capacity of the control, negative control and liposome groups were not statistically significant. However, the hypoxia group demonstrated a significantly enhanced invasive capacity, as compared with that in the control group (P<0.05). In the hypoxia β‑catenin knockdown group, reduced cell penetration and diminished invasive behavior was observed (P<0.05). In the hypoxia and double (chemical + physical) hypoxia groups, HIF‑1α, β‑catenin, urokinase‑type plasminogen activator (uPA) and matrix metalloproteinase (MMP‑7) protein and mRNA expression levels were elevated. In response to knockdown of β‑catenin expression, HIF‑1α, β‑catenin, uPA and MMP‑7 protein as well as mRNA expression levels were significantly reduced in the hypoxia β‑catenin knockdown and the double hypoxia β‑catenin knockdown groups. In an in vivo experiment, the growth rate of xenograft tumors of hypoxic and control cells was high alongside increased HIF‑1α, β‑catenin, uPA and MMP‑7 levels according to western blot and immunohistochemical analyses, while growth and protein levels of tumors from hypoxic β‑catenin knockdown cells were significantly lower and those of β‑catenin knockdown cells were lowest. In conclusion, these results suggested that HIF‑1α activation was able to regulate the Wnt/β‑catenin pathway, and that HIF‑1α may be controlled by the Wnt/β‑catenin pathway. A potential mechanism underlying SGC‑7901 tumorigenicity is the activation of the Wnt/β‑catenin signaling pathway, which activates uPA and MMP‑7 expression and contributes to the enhanced invasion of hypoxic cancer cells.

Targets of Wnt/ß-catenin transcription in penile carcinoma

Penile squamous cell carcinoma (PeCa) is a rare malignancy and little is known regarding the molecular mechanisms involved in carcinogenesis of PeCa. The Wnt signaling pathway, with the transcription activator ß-catenin as a major transducer, is a key cellular pathway during development and in disease, particularly cancer. We have used PeCa tissue arrays and multi-fluorophore labelled, quantitative, immunohistochemistry to interrogate the expression of WNT4, a Wnt ligand, and three targets of Wnt-ß-catenin transcription activation, namely, MMP7, cyclinD1 (CD1) and c-MYC in 141 penile tissue cores from 101 unique samples. The expression of all Wnt signaling proteins tested was increased by 1.6 to 3 fold in PeCa samples compared to control tissue (normal or cancer adjacent) samples (p<0.01). Expression of all proteins, except CD1, showed a significant decrease in grade II compared to grade I tumors. High magnification, deconvolved confocal images were used to measure differences in co-localization between the four proteins. Significant (p<0.04-0.0001) differences were observed for various permutations of the combinations of proteins and state of the tissue (control, tumor grades I and II). Wnt signaling may play an important role in PeCa and proteins of the Wnt signaling network could be useful targets for diagnosis and prognostic stratification of disease.

Interference with the β-catenin gene in gastric cancer induces changes to the miRNA expression profile

Aberrant activation of the Wnt/β-catenin signaling pathway plays a major role in carcinogenesis and the progression of many malignant tumors, especially gastric cancer (GC). Some research has suggested that expression of the β-catenin protein is associated with clinicopathologic factors and affects the biological behaviors of GC cells. However, the mechanism of these effects is not yet clear. Studies show that the Wnt/β-catenin pathway regulates some miRNAs. We hypothesize that oncogenic activation of β-catenin signaling is involved in the formation of GC through regulating certain microRNAs (miRNAs). The results of the current study demonstrate that expression of the β-catenin protein is associated with many clinicopathologic characteristics including the degree of differentiation, depth of tumor invasion, tumor site, and 5-year survival rate. We found that silencing the expression of β-catenin with lentiviruses could delay cell proliferation, promote apoptosis, weaken the invasive power of GC cells, and increase the sensitivity of GC cells to 5-fluorouracil in vitro. Using miRNA microarrays to detect changes in the miRNA transcriptome following interference with β-catenin in GC cells, we found that miR-1234-3p, miR-135b-5p, miR-210, and miR-4739 were commonly upregulated and that miR-20a-3p, miR-23b-5p, miR-335-3p, miR-423-5p, and miR-455-3p were commonly downregulated. These data provide a theoretical basis for the potential interaction between miRNA and the β-catenin signaling pathway in GC.

Biology of colorectal cancer

Colorectal cancer is a serious health problem, a challenge for research, and a model for studying the molecular mechanisms involved in its development. According to its incidence, this pathology manifests itself in three forms: family, hereditary, and most commonly sporadic, apparently not associated with any hereditary or familial factor. For the types having inheritance patterns and a family predisposition, the tumours develop through defined stages ranging from adenomatous lesions to the manifestation of a malignant tumour. It has been established that environmental and hereditary factors contribute to the development of colorectal cancer, as indicated by the accumulation of mutations in oncogenes, genes which suppress and repair DNA, signaling the existence of various pathways through which the appearance of tumours may occur. In the case of the suppressive and mutating tracks, these are characterised by genetic disorders related to the phenotypical changes of the morphological progression sequence in the adenoma/carcinoma. Moreover, alternate pathways through mutation in BRAF and KRAS genes are associated with the progression of polyps to cancer. This review surveys the research done at the cellular and molecular level aimed at finding specific alternative therapeutic targets for fighting colorectal cancer.

Expression of Matrix Metalloproteinase (MMP)-20 and Potential Interaction with Dentin Sialophosphoprotein (DSPP) in Human Major Salivary Glands

Matrix metalloproteinase-20 (MMP-20) expression is widely regarded as tooth-specific, with expression limited to dental hard tissues. Necessary for sound enamel formation, MMP-20 and MMP-2 proteolytically process dentin sialophosphoprotein (DSPP) into dentin sialoprotein, dentin phosphoprotein, and dentin glycoprotein during tooth formation. In the mid-2000s, three members of the small integrin-binding ligand N-linked glycoproteins (SIBLINGs) were reported to bind specifically with high affinity (nM) to, and activate, three MMPs in vitro: bone sialoprotein with MMP-2; osteopontin with MMP-3; and dentin matrix protein1 with MMP-9. The SIBLING-MMP interaction was confirmed in biological systems such as the ducts of salivary glands, where all five members of the SIBLINGs are expressed. Recently, we documented MMP-20 expression and interaction with DSPP (another member of the SIBLING family) in human oral squamous cell carcinoma. Here we report the expression of MMP-20, and confirm its co-expression and potential interaction with DSPP in human major salivary gland tissues and cell line using immunohistochemistry, immunofluorescence, western blot, quantitative RT-PCR, and proximity ligation assay. This report reinforces our earlier suggestion that the SIBLING-MMP complexes may be involved in the turnover of extracellular proteins damaged by oxidation byproducts in metabolically active duct epithelial systems.

The Wnt signalling cascade and the adherens junction complex in craniopharyngioma tumorigenesis

Craniopharyngiomas are epithelial, sellar tumours with adamantinomatous (aCP) and papillary (pCP) subtypes. The aCP type usually occurs during childhood and pCP in middle-aged adults; aCPs often contain mutations in CTNNB1, encoding β-catenin, a component of the adherens junction and a mediator of Wnt signalling. No such mutational event has been associated with pCPs, where the BRAF gene appears to be more important. In a large series of 95 craniopharyngiomas, we show that the aCP subtype harbours mutations in CTNNB1 in 52 % of cases, while the pCP subtype does not, with agreement between immunohistochemistry and sequencing methods in the majority of cases. When present, the CTNNB1 mutation is found throughout the aCP tumour, while translocation of β-catenin from membrane to cytosol and nucleus is restricted to small cell clusters near the invading tumour front. We observed translocated β-catenin in 100 % of aCPs, occurring not only in cell clusters but also in individual cells scattered throughout the tumour. We characterised the adherens junction involving α-catenin, β-catenin, γ-catenin, p120 and E-cadherin (cytosolic and membranous components). Although suggested to be important in other sellar mass tumourigenesis pathways, there was no disruption of the adherens junction in these tumours, indicating that a loss of junctional integrity is not associated with β-catenin translocation or mutation. We conclude that mutations in CTNNB1 underlie tumourigenesis in the majority of aCPs, which are distinct morphologically and at the molecular level from pCPs.

Matrix Metalloproteinase 20–Dentin Sialophosphoprotein Interaction in Oral Cancer

Matrix metalloproteinase 20 (MMP-20), widely regarded as tooth specific, participates with MMP-2 in processing dentin sialophosphoprotein (DSPP) into dentin sialoprotein, dentin phosphoprotein, and dentin glycoprotein. In biochemical system, MMP-2, MMP-3, and MMP-9 bind with high affinity to, and are activated by, specific small integrin-binding ligand N-linked glycoproteins (SIBLINGs): bone sialoprotein, osteopontin, and dentin matrix protein 1, respectively. Subsequent reports documented possible biological relevance of SIBLING-MMP interaction in vivo by showing that SIBLINGs are always coexpressed with their MMP partners. However, the cognate MMPs for 2 other SIBLINGs—DSPP and matrix extracellular phosphogylcoprotein—are yet to be identified. Our goal was to investigate MMP-20 expression and to explore preliminary evidence of its interaction with DSPP in oral squamous cell carcinomas (OSCCs). Immunohistochemistry analysis of sections from 21 cases of archived human OSCC tissues showed immunoreactivity for MMP-20 in 18 (86%) and coexpression with DSPP in all 15 cases (71%) positive for DSPP. Similarly, 28 (93%) of 30 cases of oral epithelial dysplasia were positive for MMP-20. Western blot and quantitative real-time polymerase chain reaction analysis on OSCC cell lines showed upregulation of MMP-20 protein and mRNA, respectively, while immunofluorescence showed coexpression of MMP-20 and DSPP. Colocalization and potential interaction of MMP-20 with dentin sialoprotein was confirmed by coimmunoprecipitation and mass spectrometry analysis of immunoprecipitation product from OSCC cell lysate, and in situ proximity ligation assays. Significantly, results of chromatin immunoprecipation revealed a 9-fold enrichment of DSPP at MMP-20 promoter–proximal elements. Our data provide evidence that MMP-20 has a wider tissue distribution than previously acknowledged. MMP-20–DSPP specific interaction, excluding other MMP-20–SIBLING pairings, identifies MMP-20 as DSPP cognate MMP. Furthermore, the strong DSPP enrichment at the MMP-20 promoter suggests a regulatory role in MMP-20 transcription. These novel findings provide the foundation to explore the mechanisms and significance of DSPP-MMP-20 interaction in oral carcinogenesis.

LEF1 Targeting EMT in Prostate Cancer Invasion Is Regulated by miR-34a

The microRNA-34a (miR-34a), a tumor-suppressive microRNA (miRNA), is implicated in epithelial-mesenchymal transition (EMT) and cancer stem cells. Lymphoid enhancer-binding factor-1 (LEF1) is a key transcription factor in the Wnt signaling pathway, and has been suggested to be involved in regulation of cell proliferation and invasion. Here, the molecular mechanism of miR-34a and LEF1 in cooperatively regulating prostate cancer cell invasion is described. Molecular profiling analysis of miRNA levels in prostate cancer cells revealed a negative correlation between miR-34a and LEF1 expression, and the downregulation of LEF1 by miR-34a was confirmed by luciferase assays. Furthermore, miR-34a specifically repressed LEF1 expression through direct binding to its 3'-untranslated regions (3'-UTR). miR-34a modulated the levels of LEF1 to regulate EMT in prostate cancer cells. Functionally, miR-34a negatively correlated with the migration and invasion of prostate cancer cells through LEF1. An analysis of miR-34a expression levels in matched human tumor and benign tissues demonstrated consistent and statistically significant downregulation of miR-34a in primary prostate cancer specimens. These data strongly suggest that miR-34a/LEF1 regulation of EMT plays an important role in prostate cancer migration and invasion.

IMPLICATIONS

The miR-34a-LEF1 axis represents a potential molecular target for novel therapeutic strategies in prostate cancer.

Wnt-3a-activated human fibroblasts promote human keratinocyte proliferation and matrix destruction

Aberrant Wnt regulation, detectable by nuclear translocation of beta-catenin, is a hallmark of many cancers including skin squamous cell carcinomas (SCCs). By analyzing primary human skin SCCs, we demonstrate that nuclear beta-catenin is not restricted to SCC cells but also detected in stromal fibroblasts, suggesting an important role for aberrant Wnt regulation also in the tumor microenvironment. When human keratinocytes and fibroblasts were treated with Wnt-3a, fibroblasts proved to be more responsive. Accordingly, Wnt-3a did not alter HaCaT cell functions in a cell-autonomous manner. However, when organotypic cultures (OTCs) were treated with Wnt-3a, HaCaT keratinocytes responded with increased proliferation. As nuclear beta-catenin was induced only in the fibroblasts, this argued for a Wnt-dependent, paracrine keratinocyte stimulation. Global gene expression analysis of Wnt-3a-stimulated fibroblasts identified genes encoding interleukin-8 (IL-8) and C-C motif chemokine 2 (CCL-2) as well as matrix metalloproteinase-1 (MMP-1) as Wnt-3a targets. In agreement, we show that IL-8 and CCL-2 were secreted in high amounts by Wnt-3a-stimulated fibroblasts also in OTCs. The functional role of IL-8 and CCL-2 as keratinocyte growth regulators was confirmed by directly stimulating HaCaT cell proliferation in conventional cultures. Most important, neutralizing antibodies against IL-8 and CCL-2 abolished the Wnt-dependent HaCaT cell hyperproliferation in OTCs. Additionally, MMP-1 was expressed in high amounts in Wnt-3a-stimulated OTCs and degraded the stromal matrix. Thus, our data show that Wnt-3a stimulates fibroblasts to secrete both keratinocyte proliferation-inducing cytokines and stroma-degrading metalloproteinases, thereby providing evidence for a novel Wnt deregulation in the tumor-stroma directly contributing to skin cancer progression.

Tropomodulin 1 expression driven by NF-κB enhances breast cancer growth

Triple-negative breast cancers (TNBC), which include the basal-like and claudin-low disease subtypes, are aggressive malignancies for which effective therapeutic targets are lacking. NF-κB activation has an established role in breast malignancy, and it is higher in TNBC than other breast cancer subtypes. On this basis, we hypothesized that proteins derived from NF-κB target genes might be molecular targets for TNBC therapy. In this study, we conducted a microarray-based screen for novel NF-κB-inducible proteins as candidate therapeutic targets, identifying tropomodulin 1 (TMOD1) as a lead candidate. TMOD1 expression was regulated directly by NF-κB and was significantly higher in TNBC than other breast cancer subtypes. TMOD1 elevation is associated with enhanced tumor growth in a mouse tumor xenograft model and in a 3D type I collagen culture. TMOD1-dependent tumor growth was correlated with MMP13 induction, which was mediated by TMOD1-dependent accumulation of β-catenin. Overall, our study highlighted a novel TMOD1-mediated link between NF-κB activation and MMP13 induction, which accounts in part for the NF-κB-dependent malignant phenotype of TNBC.

Proton pump inhibitor pantoprazole abrogates adriamycin-resistant gastric cancer cell invasiveness via suppression of Akt/GSK-β/β-catenin signaling and epithelial-mesenchymal transition

The effect of proton pump inhibitor (PPI) on cancer risk has received much attention recently. In this study, we investigated the mechanism underlying multidrug resistance and the effect of a PPI pantoprazole using an adriamycin-resistant gastric cancer cell model (SGC7901/ADR). Compared with the parental cell line, SGC7901/ADR cells showed reduced proliferation rate, but higher resistance to adriamycin under both anchorage-dependent and -independent conditions. Notably, SGC7901/ADR cells underwent epithelial to mesenchymal transition (EMT) and showed increased migrating and invading capabilities. At molecular level, SGC7901/ADR cells showed strong activation of Wnt/β-catenin signaling pathway compared with parental sensitive cells. Interestingly, we found that a PPI pantoprazole can effectively reverse the aggressiveness and EMT marker expression of SGC7901/ADR cells. Furthermore, pantoprazole treatment resulted in a profound reduction of both total and phosphorylated forms of Akt and GSK-3β, which in turn suppressed the adriamycin-induced Wnt/β-catenin signaling in SGC7901/ADR cells. Taken together, we demonstrate that the aggressive phenotype of adriamycin-resistant SGC7901/ADR cells is mediated by induction of EMT and activation of the canonical Wnt/β-catenin signaling pathway. And for the first time, we show that it is possible to suppress the invasiveness of SGC7901/ADR cells by pantoprazole which targets the EMT and Akt/GSK-3β/β-catenin signaling.

The parasite Entamoeba histolytica exploits the activities of human matrix metalloproteinases to invade colonic tissue

Intestinal invasion by the protozoan parasite Entamoeba histolytica is characterized by remodelling of the extracellular matrix (ECM). The parasite cysteine proteinase A5 (CP-A5) is thought to cooperate with human matrix metalloproteinases (MMPs) involved in ECM degradation. Here, we investigate the role CP-A5 plays in the regulation of MMPs upon mucosal invasion. We use human colon explants to determine whether CP-A5 activates human MMPs. Inhibition of the MMPs' proteolytic activities abolishes remodelling of the fibrillar collagen structure and prevents trophozoite invasion of the mucosa. In the presence of trophozoites, MMPs-1 and -3 are overexpressed and are associated with fibrillar collagen remodelling. In vitro, CP-A5 performs the catalytic cleavage needed to activate pro-MMP-3, which in turn activates pro-MMP-1. Ex vivo, incubation with recombinant CP-A5 was enough to rescue CP-A5-defective trophozoites. Our results suggest that MMP-3 and/or CP-A5 inhibitors may be of value in further studies aiming to treat intestinal amoebiasis.

Bidirectional cross-regulation between the endothelial nitric oxide synthase and β-catenin signalling pathways

AIMS

β-catenin has been shown to be regulated by inducible nitric oxide synthase (NOS) in endothelial cells. We investigated here whether β-catenin interacts with and regulates endothelial NOS (eNOS) and whether eNOS activation promotes β-catenin signalling.

METHODS AND RESULTS

We identified β-catenin as a novel eNOS binding protein in human umbilical vein endothelial cells (HUVECs) by mass spectroscopy and western blot analyses of β-catenin and eNOS immunoprecipitates. This was confirmed by in situ proximity ligation assay. eNOS activity, assessed by cGMP production and eNOS phosphorylation (Ser1177), was enhanced in β-catenin(-/-) mouse pulmonary endothelial cells (MPECs) relative to wild-type MPECs. eNOS activation (using adenosine, salbutamol, thrombin, or histamine), or application of an NO donor (spermine NONOate) or cGMP-analogue (8-bromo-cGMP) caused nuclear translocation of β-catenin in HUVEC as shown by western blotting of nuclear extracts. Exposure to spermine NONOate, 8-bromo-cGMP, or sildenafil (a phosphodiesterase type 5 inhibitor) also increased the expression of β-catenin-dependent transcripts, IL-8, and cyclin D1. Stimulation of wild-type MPECs with basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), spermine NONOate, 8-bromo-cGMP, or sildenafil increased tube length relative to controls in an angiogenesis assay. These responses were abrogated in β-catenin(-/-) MPECs, with the exception of that to bFGF which is NO-independent. In C57BL/6 mice, subcutaneous VEGF-supplemented Matrigel plugs containing β-catenin(-/-) MPECs exhibited reduced angiogenesis compared with plugs containing wild-type MPECs. Angiogenesis was not altered in bFGF-supplemented Matrigel.

CONCLUSION

These data reveal bidirectional cross-talk and regulation between the NO-cGMP and β-catenin signalling pathways.

Activation of c-Myc and Cyclin D1 by JCV T-Antigen and β-catenin in colon cancer

During the last decade, mounting evidence has implicated the human neurotropic virus JC virus in the pathology of colon cancer. However, the mechanisms of JC virus-mediated oncogenesis are still not fully determined. One candidate to mediate these effects is the viral early transcriptional product T-Antigen, which has the ability to inactivate cell cycle regulatory proteins such as p53. In medulloblastomas, T-Antigen has been shown to bind the Wnt signaling pathway protein β-catenin; however, the effects of this interaction on downstream cell cycle regulatory proteins remain unknown. In light of these observations, we investigated the association of T-Antigen and nuclear β-catenin in colon cancer cases and the effects of this complex in the activation of the transcription and cell cycle regulators c-Myc and Cyclin D1 in vitro. Gene amplification demonstrated the presence of viral sequences in 82.4% of cases and we detected expression of T-Antigen in 64.6% of cases by immunohistochemistry. Further, we found that T-Antigen and β-catenin co-localized in the nuclei of tumor cells and we confirmed the physical binding between these two proteins in vitro. The nuclear presence of T-Antigen and β-catenin resulted in the significant enhancement of TCF-dependent promoter activity and activation of the β-catenin downstream targets, c-Myc and Cyclin D1. These observations provide further evidence for a role of JCV T-Antigen in the dysregulation of the Wnt signaling pathway and in the pathogenesis of colon cancer.

Beyond TGFβ--novel ways to target airway and parenchymal fibrosis

Within the lungs, fibrosis can affect both the parenchyma and the airways. Fibrosis is a hallmark pathological change in the parenchyma in patients with idiopathic pulmonary fibrosis (IPF), whilst in asthma or chronic obstructive pulmonary disease (COPD) fibrosis is a component of the remodelling of the airways. In the past decade, significant advances have been made in understanding the disease behaviour and pathogenesis of parenchymal and airway fibrosis and as a result a variety of novel therapeutic targets for slowing or preventing progression of these fibrotic changes have been identified. This review highlights a number of these targets and discusses the potential for treating parenchymal or airway fibrosis through these mediators/pathways in the future.

SDF-1/CXCR4 promotes epithelial-mesenchymal transition and progression of colorectal cancer by activation of the Wnt/β-catenin signaling pathway

Stromal cell-derived factor 1 (SDF-1) and its receptor, CXCR4, play an important role in angiogenesis and are associated with tumor progression. This study aimed to investigate the role of SDF-1/CXCR4-mediated epithelial-mesenchymal transition (EMT) and the progression of colorectal cancer (CRC) as well as the underlying mechanisms. The data showed that expression of CXCR4 and β-catenin mRNA and protein was significantly higher in CRC tissues than in distant normal tissues. CXCR4 expression was associated with β-catenin expression in CRC tissues, whereas high CXCR4 expression was strongly associated with low E-cadherin, high N-cadherin, and high vimentin expression, suggesting a cross talk between the SDF-1/CXCR4 axis and Wnt/β-catenin signaling pathway in CRC. In vitro, SDF-1 induced CXCR4-positive colorectal cancer cell invasion and EMT by activation of the Wnt/β-catenin signaling pathway. In contrast, SDF-1/CXCR4 axis activation-induced colorectal cancer invasion and EMT was effectively inhibited by the Wnt signaling pathway inhibitor Dickkopf-1. In conclusion, CXCR4-promoted CRC progression and EMT were regulated by the Wnt/β-catenin signaling pathway. Thus, targeting of the SDF-1/CXCR4 axis could have clinical applications in suppressing CRC progression.

Serum endostatin levels are elevated in colorectal cancer and correlate with invasion and systemic inflammatory markers

Background:

Endostatin, a fragment of collagen XVIII, is an endogenous angiogenesis inhibitor with anti-tumour functions. However, elevated circulating endostatin concentrations have been found in several human cancers including colorectal cancer (CRC).

Methods:

Serum endostatin levels were measured by enzyme-linked immunoassay from a series of 143 patients with CRC and from 84 controls, and correlated with detailed clinicopathological features of CRC, serum leukocyte differential count and C-reactive protein (CRP) levels.

Results:

Patients with CRC had higher serum endostatin levels than the controls (P=0.005), and high levels associated with age, tumour invasion through the muscularis propria and poor differentiation, but not with metastases. Endostatin levels showed a positive correlation with the markers of systemic inflammatory response and a negative correlation with the densities of tumour-infiltrating mast cells and dendritic cells. Collagen XVIII was expressed in tumour stroma most strikingly in blood vessels and capillaries, and in the muscle layer of the bowel wall.

Conclusions:

Elevated endostatin levels in CRC correlate with systemic inflammation and invasion through the muscularis propria. Increased endostatin level may be a result of invasion-related cleavage of collagen XVIII expressed in the bowel wall. The negative correlations between serum endostatin and intratumoural mast cells and immature dendritic cells may reflect angiogenesis inhibition by endostatin.

Kidney tubular β-catenin signaling controls interstitial fibroblast fate via epithelial-mesenchymal communication

Activation of β-catenin, the principal mediator of canonical Wnt signaling, is a common pathologic finding in a wide variety of chronic kidney diseases (CKD). While β-catenin is induced predominantly in renal tubular epithelium in CKD, surprisingly, depletion of tubular β-catenin had little effect on the severity of renal fibrosis. Interestingly, less apoptosis was detected in interstitial fibroblasts in knockout mice, which was accompanied by a decreased expression of Bax and Fas ligand (FasL). Tubule-specific knockout of β-catenin diminished renal induction of matrix metalloproteinase (MMP-7), which induced FasL expression in interstitial fibroblasts and potentiated fibroblast apoptosis in vitro. These results demonstrate that loss of tubular β-catenin resulted in enhanced interstitial fibroblast survival due to decreased MMP-7 expression. Our studies uncover a novel role of the tubular β-catenin/MMP-7 axis in controlling the fate of interstitial fibroblasts via epithelial-mesenchymal communication.

Expression and activity levels of matrix metalloproteinase-7 and in situ localization of caseinolytic activity in colorectal cancer

OBJECTIVES

Matrix metalloproteinase-7 is capable of degrading several ECM and non-ECM molecules and contributes to colorectal cancer progression and metastasis. Here, we examined the significance of MMP-7 in colorectal tumors by detecting active and latent MMP-7 levels and localization of its caseinolytic activity.

DESIGN AND METHODS

We investigated expression levels, localization, and proteolytic activity of MMP-7 and local caseinolytic activity in colorectal tumor and paired normal tissues by using real time PCR, casein zymography, immunohistochemistry and in situ casein zymography, respectively. In addition the results were compared with clinicopathological variables.

RESULTS

Real time PCR and immunohistochemistry showed that MMP-7 expressions were higher in colorectal tumor tissues than in normal tissues. Also, mRNA expressions of MMP-7 were positively correlated with tumor and pathological stages and negatively correlated with age. Furthermore, MMP-7 mRNA expression had a sensitivity of 81.3% and a specificity of 81.2% at a cut-off value of 0.0006, making it a potential marker for diagnosis of colorectal cancer. According to casein zymography, pro- and active MMP-7 levels were also elevated in tumor tissues. In addition, we assessed local caseinolytic activity using in situ casein zymography. Increased immunoreactivity of MMP-7 and local caseinolytic activity were found in neoplastic cells but not in stromal cells.

CONCLUSION

We emphasized the significant role of MMP-7 in diagnosis and progression and/or development of colorectal cancer.

Loss of E-cadherin promotes migration and invasion of cholangiocarcinoma cells and serves as a potential marker of metastasis

Tumor progression is characterized by loss of cell adhesion and increase of invasion and metastasis. E-cadherin, a cell adhesion molecule, is frequently downregulated and has been proposed as an important mediator in epithelial-mesenchymal transition (EMT) in tumors. In this study, we investigated the expression of E-cadherin and its association with cancer invasion and prognosis in cholangiocarcinoma (CCA). Immunohistochemistry results demonstrated a statistically significant association between the positive metastasis status with low E-cadherin protein expression in human CCA tissues (P = 0.04). Statistical trends were identified for low E-cadherin level and shorter survival time (P = 0.08). Targeting the E-cadherin expression in CCA cells with siRNA caused upregulation of vimentin, a mesenchymal marker, and disappearance of the E-cadherin/β-catenin adhesion complex from cell membranes. Moreover, migration and invasion abilities of the cells were increased under this condition. These findings suggest that reduction of E-cadherin contributes to CCA progression by attenuating the strength of cellular adhesion, which affects motility as well as regulating the expression of EMT-related genes during CCA invasion and metastasis. Thus, E-cadherin can act as a central modulator of tumor cell phenotype and is a potential metastasis marker in CCA.

Cooperativity of E-cadherin and Smad4 loss to promote diffuse-type gastric adenocarcinoma and metastasis

Loss of E-cadherin (CDH1), Smad4, and p53 has been shown to play an integral role in gastric, intestinal, and breast cancer formation. Compound conditional knockout mice for Smad4, p53, and E-cadherin were generated to define and compare the roles of these genes in gastric, intestinal, and breast cancer development by crossing with Pdx-1-Cre, Villin-Cre, and MMTV-Cre transgenic mice. Interestingly, gastric adenocarcinoma was significantly more frequent in Pdx-1-Cre;Smad4(F/F);Trp53(F/F);Cdh1(F) (/+) mice than in Pdx-1-Cre;Smad4(F/F);Trp53(F/F);Cdh1(+/+) mice, demonstrating that Cdh1 heterozygosity accelerates the development and progression of gastric adenocarcinoma, in combination with loss of Smad4 and p53. Pdx-1-Cre;Smad4(F/F);Trp53(F/F);Cdh1(F) (/+) mice developed gastric adenocarcinomas without E-cadherin expression. However, intestinal and mammary adenocarcinomas with the same genetic background retained E-cadherin expression and were phenotypically similar to mice with both wild-type Cdh1 alleles. Lung metastases were identified in Pdx-1-Cre;Smad4(F/F);Trp53(F/F);Cdh1(F) (/+) mice, but not in the other genotypes. Nuclear β-catenin accumulation was identified at the invasive tumor front of gastric adenocarcinomas arising in Pdx-1-Cre;Smad4(F/F);Trp53(F/F);Cdh1(F) (/+) mice. This phenotype was less prominent in mice with intact E-cadherin or Smad4, indicating that the inhibition of β-catenin signaling by E-cadherin or Smad4 downregulates signaling pathways involved in metastases in Pdx-1-Cre;Smad4(F/F);Trp53(F/F);Cdh1(F) (/+) mice. Knockdown of β-catenin significantly inhibited the migratory activity of Pdx-1-Cre;Smad4(F/F);Trp53(F/F);Cdh1(F) (/+) cell lines. Thus, loss of E-cadherin and Smad4 cooperates with p53 loss to promote the development and metastatic progression of gastric adenocarcinomas, with similarities to human gastric adenocarcinoma.

IMPLICATIONS

This study demonstrates that inhibition of β-catenin is a converging node for the antimetastatic signaling pathways driven by E-cadherin and Smad4 in Pdx-1-Cre;Smad4(F/F);Trp53(F/F);Cdh1(F) (/+) mice, providing novel insights into mechanisms for gastric cancer metastasis.

Downregulation of SCAI enhances glioma cell invasion and stem cell like phenotype by activating Wnt/β-catenin signaling

SCAI (suppressor of cancer cell invasion), has been recently characterized as a novel tumor suppressor that inhibits the invasive migration of several human tumor cells. However, the expression pattern, biological role and molecular mechanism of SCAI in human glioma remain unknown. In this study, we found that levels of SCAI protein and mRNA expression were significantly down-regulated in glioma tissues and cell lines. Overexpression of SCAI inhibited, but silencing of SCAI robustly promoted the invasive and cancer stem cell-like phenotypes of glioma cells. Furthermore, we demonstrated that SCAI downregualtion activated the Wnt/β-catenin signaling, and blockade of the Wnt/β-catenin pathway abrogated the effects of SCAI downregulation on glioma cell aggressiveness. Taken together, our results provide the first demonstration of SCAI downregulation in glioma, and its downregulation contributes to increased glioma cell invasion and self-renewal by activating the Wnt/β-catenin pathway.

Lemur tyrosine kinase-3 is a significant prognostic marker for patients with colorectal cancer

Lemur tyrosine kinase-3 (LMTK3) belongs to the family of serine-threonine-tyrosine kinases and the aberrant expression of LMTK3 was observed in several human malignancies. However, the association of LMTK3 with clinical outcomes in colorectal cancer patients is unclear. Thus, this present study was to evaluate the association of LMTK3 expression level with clinicopathologic factors and prognosis of patients with colorectal cancer (CRC). The expression level of LMTK3 in 69 archival paraffin-embedded colorectal tumor tissue specimens was examined by immunohistochemistry (IHC). As a result, we found that the LMTK3 expression level was significantly elevated in CRC tissues as compared with Crohn's disease or colorectal polyp tissues (P<0.0001, P<0.0001, respectively). Positive LMTK3 signals in the colorectal cancer cells were observed in about 89.9% (62 of 69) CRC tissue specimens. Additionally, LMTK3 expression was significantly correlated with lymph node metastasis and tumor-node-metastasis (TNM) classification (P=0.003, and P=0.008, respectively), but not with sex, age, tumor location, histological differentiation, tumor size, or depth of tumor invasion (all P>0.05). Kaplan-Meier survival curves showed that the overall survival rate was significantly higher in the patients with low expression of LMTK3 when compared with those patients with high LMTK3 (P=0.010). Moreover, multivariate analysis revealed that LMTK3 expression was an independent prognostic factor for CRC patients (P=0.047). These results suggest that LMTK3 protein could serve as a prognostic marker for CRC patients.