The Wnt signal transduction pathway in stem cells and cancer cells: influence on cellular invasion

Identification and validation of metastasis-related gene ZG16 in the prognosis and progression in colorectal cancer

Background

Metastasis remains the leading cause of mortality among colorectal cancer (CRC) patients. Identification of new metastasis-related genes are critical to improve colorectal cancer prognosis.

Methods

Data on mRNA expression in metastatic and primary CRC was obtained from the Gene Expression Omnibus (GEO) database, including GSE81986, GSE41568, GSE71222, GSE21510, and GSE14333. Additionally, data concerning mRNA expression in colon cancer (COAD) and adjacent normal tissues were acquired from The Cancer Genome Atlas (TCGA) database. Hub genes were identified by weighted gene co-expression network analysis (WGCNA) and differential gene expression analysis. Moreover, we assessed the impact of hub gene expression on both overall survival (OS) and disease-free survival (DFS) in patients and identified ZG16 as a potential target. We generated CRC cell lines transfected with lentivirus OE-ZG16 to investigate proliferation, invasion, and migration in vitro. To further elucidate the involvement of ZG16, we utilized gene set enrichment analysis (GSEA) to identify enriched pathways, which were subsequently validated via Western blot analysis.

Results

Five datasets containing primary and metastatic CRC samples from GEO database and CRC samples from TCGA database were included in this study and 29 hub genes were identified by WGCNA and differentially expressed gene (DEG) analysis. Low expression of the hub genes (CLCA1 and ZG16) was associated with poor DFS and OS. We confirmed the low expression of ZG16 in CRC using external database and IHC analysis at both transcriptional and protein levels. In addition, the expression of ZG16 was notably elevated in NCM460 cells in comparison to CRC cell lines. The overexpression of ZG16 in CRC cells has been shown to inhibit the proliferation, invasion, and migration of CRC cells. Furthermore, the overexpression of ZG16 has been found to suppress the activation of the epithelial-mesenchymal transition (EMT) and Wnt/β-catenin signaling pathways in CRC.

Conclusion

ZG16 may serve as a promising therapeutic target for metastatic CRC treatment.

About a Possible Impact of Endodontic Infections by Fusobacterium nucleatum or Porphyromonas gingivalis on Oral Carcinogenesis: A Literature Overview

Periodontitis is linked to the onset and progression of oral squamous cell carcinoma (OSCC), an epidemiologically frequent and clinically aggressive malignancy. In this context, Fusobacterium (F.) nucleatum and Porphyromonas (P.) gingivalis, two bacteria that cause periodontitis, are found in OSCC tissues as well as in oral premalignant lesions, where they exert pro-tumorigenic activities. Since the two bacteria are present also in endodontic diseases, playing a role in their pathogenesis, here we analyze the literature searching for information on the impact that endodontic infection by P. gingivalis or F. nucleatum could have on cellular and molecular events involved in oral carcinogenesis. Results from the reviewed papers indicate that infection by P. gingivalis and/or F. nucleatum triggers the production of inflammatory cytokines and growth factors in dental pulp cells or periodontal cells, affecting the survival, proliferation, invasion, and differentiation of OSCC cells. In addition, the two bacteria and the cytokines they induce halt the differentiation and stimulate the proliferation and invasion of stem cells populating the dental pulp or the periodontium. Although most of the literature confutes the possibility that bacteria-induced endodontic inflammatory diseases could impact on oral carcinogenesis, the papers we have analyzed and discussed herein recommend further investigations on this topic.

NCAPD2 promotes the malignant progression of oral squamous cell carcinoma via the Wnt/β-catenin pathway

Oral squamous cell carcinoma (OSCC) is the most common type of oral cancer, with a poor prognosis, yet the underlying mechanism needs further exploration. Non-SMC condensin I complex subunit D2 (NCAPD2) is a widely expressed protein in OSCC, but its role in tumor development is unclear. This study aimed to explore NCAPD2 expression and its biological function in OSCC. NCAPD2 expression in OSCC cell lines and tissue specimens was analyzed using quantitative polymerase chain reaction, western blotting, and immunohistochemistry. Cancer cell growth was evaluated using cell proliferation, 5-Ethynyl-2'-deoxyuridine (EdU) staining, and colony formation assays. Cell migration was evaluated using wound healing and Transwell assays. Apoptosis was detected using flow cytometry. The influence of NCAPD2 on tumor growth in vivo was evaluated in a mouse xenograft model. NCAPD2 expression was significantly higher in OSCC than that in normal oral tissue. In vitro, the knockdown of NCAPD2 inhibited OSCC cell proliferation and promoted apoptosis. NCAPD2 depletion also significantly inhibited the migration of OSCC cells. Moreover, NCAPD2 overexpression induced inverse effects on OSCC cell phenotypes. In vivo, we demonstrated that downregulating NCAPD2 could inhibit the tumorigenicity of OSCC cells. Mechanically, OSCC regulation by NCAPD2 involved the Wnt/β-catenin signaling pathway. These results suggest NCAPD2 as a novel oncogene with an important role in OSCC development and a candidate therapeutic target for OSCC.

ECM1 promotes migration and invasion in endometriosis

Extracellular matrix protein 1 (ECM1) is a glycoprotein that may be a key player in tumorigenesis and tumor progression. However, knowledge regarding the role of ECM1 in endometriosis (EM) is still lacking. Microarray analyses were performed to compare the mRNA expression patterns between paired EU tissues and ectopic endometrial (EC) tissues (n = 4) from EM patients. ECM1 expression was significantly increased in the eutopic endometrial (EU) tissues than paired EC tissues of endometriotic patients and normal endometrial (NE) tissues of controls without EM. Blocking ECM1 with siRNA attenuated the migration and invasion of hEM15A cells and modified the distribution of the F-actin cytoskeleton. We conducted microarray analyses and bioinformatics analyses to investigate the differentially expressed genes (DEGs) and related pathways regulated by ECM1. A total of 161 DEGs between the siECM1 and the negative control (siNC) treatments were identified, consisting of 79 downregulated genes and 82 upregulated genes. Enriched DEGs were associated with 9 gene ontology (GO) terms. Moreover, a protein-protein interaction (PPI) network was constructed for the hub genes and modules. Radixin (RDX) was the second most downregulated gene in the siECM1 group compared with the siNC group. ECM1 knockdown significantly decreased the expression of RDX, RhoC, ROCK1, N-cadherin and β-catenin but not ROCK2. ECM1 showed high tissue-specific expression in EU tissues from EM patients, and may contribute to the migration, invasion and reorganization of the F-actin cytoskeleton in eutopic endometrial stromal cells via the RhoC/ROCK1 signaling pathway in EM.

MicroRNA-191 regulates oral squamous cell carcinoma cells growth by targeting PLCD1 via the Wnt/β-catenin signaling pathway

BACKGROUND

Studies have shown that microRNA-191 (miR-191) is involved in the development and progression of a variety of tumors. However, the function and mechanism of miR-191 in oral squamous cell carcinoma (OSCC) have not been clarified.

METHODS

The expression level of miR-191 in tumor tissues of patients with primary OSCC and OSCC cell lines were detected using real-time quantitative polymerase chain reaction (RT-qPCR) and western blot. OSCC cells were treated with miR-191 enhancers and inhibitors to investigate the effects of elevated or decreased miR-191 expression on OSCC cells proliferation, migration, cell cycle, and tumorigenesis. The target gene of miR-191 in OSCC cells were analyzed by dual-Luciferase assay, and the downstream signaling pathway of the target genes was detected using western blot assay.

RESULTS

The expression of miR-191 was significantly upregulated in OSCC tissues and cell lines. Upregulation of miR-191 promoted proliferation, migration, invasion, and cell cycle progression of OSCC cells, as well as tumor growth in nude mice. Meanwhile, reduced expression of miR-191 inhibited these processes. Phospholipase C delta1 (PLCD1) expression was significantly downregulated, and negatively correlated with the expression of miR-191 in OSCC tissues. Dual-Luciferase assays showed that miR-191-5p could bind to PLCD1 mRNA and regulate PLCD1 protein expression. Western blot assay showed that the miR-191 regulated the expression of β-catenin and its downstream gene through targeting PLCD1.

CONCLUSION

MicroRNA-191 regulates oral squamous cell carcinoma cells growth by targeting PLCD1 via the Wnt/β-catenin signaling pathway. Thus, miR-191 may serve as a potential target for the treatment of OSCC.

Perspective: Why and How Ubiquitously Distributed, Vascular-Associated, Pluripotent Stem Cells in the Adult Body (vaPS Cells) Are the Next Generation of Medicine

A certain cell type can be isolated from different organs in the adult body that can differentiate into ectoderm, mesoderm, and endoderm, providing significant support for the existence of a certain type of small, vascular-associated, pluripotent stem cell ubiquitously distributed in all organs in the adult body (vaPS cells). These vaPS cells fundamentally differ from embryonic stem cells and induced pluripotent stem cells in that the latter possess the necessary genetic guidance that makes them intrinsically pluripotent. In contrast, vaPS cells do not have this intrinsic genetic guidance, but are able to differentiate into somatic cells of all three lineages under guidance of the microenvironment they are located in, independent from the original tissue or organ where they had resided. These vaPS cells are of high relevance for clinical application because they are contained in unmodified, autologous, adipose-derived regenerative cells (UA-ADRCs). The latter can be obtained from and re-applied to the same patient at the point of care, without the need for further processing, manipulation, and culturing. These findings as well as various clinical examples presented in this paper demonstrate the potential of UA-ADRCs for enabling an entirely new generation of medicine for the benefit of patients and healthcare systems.

CDX2 inhibits epithelial-mesenchymal transition in colorectal cancer by modulation of Snail expression and β-catenin stabilisation via transactivation of PTEN expression

Background

Emerging evidence suggests the involvement of caudal-related homoeobox transcription factor 2 (CDX2) in tumorigenesis of various cancers. Although CDX2 functions in cancer invasion and metastasis, fewer studies focus on the role of CDX2 during the induction of epithelial–mesenchymal transition (EMT) in colorectal cancer (CRC).

Methods

Immunohistochemical analysis of CDX2 was performed. A series of in vitro and in vivo experiments were conducted to reveal the role of CDX2 in the invasion and metastasis of CRC.

Results

CDX2 was downregulated in CRC tissues and reduced CDX2 correlated with poor prognosis. Knockdown of CDX2 promoted colon cancer cell invasion in vitro and facilitated liver metastasis in vivo with inducing EMT phenotypes. Further investigation indicated that CDX2 retarded Akt and GSK-3β phosphorylation, and thereby diminished Snail expression, β-catenin stabilisation and nuclear translocation. The depletion of β-catenin neutralised the regulation of Slug and ZEB1 by CDX2 knockdown. Mechanistically, CDX2 antagonised PI3K/Akt activity in CRC by modulating PTEN expression. CDX2 directly bound to the promoter of PTEN and transactivated its expression.

Conclusions

Our study first uncovered that CDX2 inhibits EMT and metastasis of CRC by regulation of Snail expression and β-catenin stabilisation via transactivation of PTEN expression.

Dissecting molecular network structures using a network subgraph approach

Biological processes are based on molecular networks, which exhibit biological functions through interactions of genetic elements or proteins. This study presents a graph-based method to characterize molecular networks by decomposing the networks into directed multigraphs: network subgraphs. Spectral graph theory, reciprocity and complexity measures were used to quantify the network subgraphs. Graph energy, reciprocity and cyclomatic complexity can optimally specify network subgraphs with some degree of degeneracy. Seventy-one molecular networks were analyzed from three network types: cancer networks, signal transduction networks, and cellular processes. Molecular networks are built from a finite number of subgraph patterns and subgraphs with large graph energies are not present, which implies a graph energy cutoff. In addition, certain subgraph patterns are absent from the three network types. Thus, the Shannon entropy of the subgraph frequency distribution is not maximal. Furthermore, frequently-observed subgraphs are irreducible graphs. These novel findings warrant further investigation and may lead to important applications. Finally, we observed that cancer-related cellular processes are enriched with subgraph-associated driver genes. Our study provides a systematic approach for dissecting biological networks and supports the conclusion that there are organizational principles underlying molecular networks.

MicroRNAs in the Migration of Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) represent a promising source of cell-based therapies for treatment of a wide variety of injuries and diseases. Their tropism and migration to the damaged sites, which are elicited by cytokines secreted from tissues around pathology, are the prerequisite for tissue repair and regeneration. Better understanding of the elicited-migration of MSCs and discovering conditions that elevate their migration ability, will help to increase their homing to pathologies and improve therapeutic efficacy. It is increasingly recognized that microRNAs are important regulators of cell migration. Here we summarize current understanding of the microRNA-regulated migration of MSCs.

Application of a 3D Bioprinted Hepatocellular Carcinoma Cell Model in Antitumor Drug Research

The existing in vitro models for antitumor drug screening have great limitations. Many compounds that inhibit 2D cultured cells do not exhibit the same pharmacological effects in vivo, thereby wasting human and material resources as well as time during drug development. Therefore, developing new models is critical. The 3D bioprinting technology has greater advantages in constructing human tissue compared with sandwich culture and organoid construction. Here, we used 3D bioprinting technology to construct a 3D model with HepG2 cells (3DP-HepG2). The biological activities of the model were evaluated by immunofluorescence, real-time quantitative PCR, and transcriptome sequencing. Compared with the traditional 2D cultured tumor cells (2D-HepG2), 3DP-HepG2 showed significantly improved expression of tumor-related genes, including ALB, AFP, CD133, IL-8, EpCAM, CD24, and β-TGF genes. Transcriptome sequencing analysis revealed large differences in gene expression between 3DP-HepG2 and 2D-HepG2, especially genes related to hepatocyte function and tumor. We also compared the effects of antitumor drugs in 3DP-HepG2 and 2D-HepG2, and found that the large differences in drug resistance genes between the models may cause differences in the drugs' pharmacodynamics.

The basics of epithelial-mesenchymal transition (EMT): A study from a structure, dynamics, and functional perspective

Epithelial-mesenchymal transition (EMT) is a key step in transdifferentiation process in solid cancer development. Forthcoming evidence suggest that the stratified program transforms polarized, immotile epithelial cells to migratory mesenchymal cells associated with enhancement of breast cancer stemness, metastasis, and drug resistance. It involves primarily several signaling pathways, such as transforming growth factor-β (TGF-β), cadherin, notch, plasminogen activator protein inhibitor, urokinase plasminogen activator, and WNT/beta catenin pathways. However, current understanding on the crosstalk of multisignaling pathways and assemblies of key transcription factors remain to be explored. In this review, we focus on the crosstalk of signal transduction pathways linked to the current therapeutic and drug development strategies. We have also performed the computational modeling on indepth the structure and conformational dynamic studies of regulatory proteins and analyze molecular interactions with their associate factors to understand the complicated process of EMT in breast cancer progression and metastasis. Electrostatic potential surfaces have been analyzed that help in optimization of electrostatic interactions between the protein and its ligand. Therefore, understanding the biological implications underlying the EMT process through molecular biology with biocomputation and structural biology approaches will enable the development of new therapeutic strategies to sensitize tumors to conventional therapy and suppress their metastatic phenotype.

KIAA1199 is a secreted molecule that enhances osteoblastic stem cell migration and recruitment

Factors mediating mobilization of osteoblastic stem and progenitor cells from their bone marrow niche to be recruited to bone formation sites during bone remodeling are poorly known. We have studied secreted factors present in the bone marrow microenvironment and identified KIAA1199 (also known as CEMIP, cell migration inducing hyaluronan binding protein) in human bone biopsies as highly expressed in osteoprogenitor reversal cells (Rv.C) recruited to the eroded surfaces (ES), which are the future bone formation sites. In vitro, KIAA1199 did not affect the proliferation of human osteoblastic stem cells (also known as human bone marrow skeletal or stromal stem cells, hMSCs); but it enhanced cell migration as determined by scratch assay and trans-well migration assay. KIAA1199 deficient hMSCs (KIAA1199down) exhibited significant changes in cell size, cell length, ratio of cell width to length and cell roundness, together with reduction of polymerization actin (F-actin) and changes in phos-CFL1 (cofflin1), phos-LIMK1 (LIM domain kinase 1) and DSTN (destrin), key factors regulating actin cytoskeletal dynamics and cell motility. Moreover, KIAA1199down hMSC exhibited impaired Wnt signaling in TCF-reporter assay and decreased expression of Wnt target genes and these effects were rescued by KIAA1199 treatment. Finally, KIAA1199 regulated the activation of P38 kinase and its associated changes in Wnt-signaling. Thus, KIAA1199 is a mobilizing factor that interacts with P38 and Wnt signaling, and induces changes in actin cytoskeleton, as a mechanism mediating recruitment of hMSC to bone formation sites.

CDX2 inhibits the proliferation and tumor formation of colon cancer cells by suppressing Wnt/β-catenin signaling via transactivation of GSK-3β and Axin2 expression

Caudal-related homeobox transcription factor 2 (CDX2), an intestine-specific nuclear transcription factor, has been strongly implicated in the tumourigenesis of various human cancers. However, the functional role of CDX2 in the development and progression of colorectal cancer (CRC) is not well known. In this study, CDX2 knockdown in colon cancer cells promoted cell proliferation in vitro, accelerated tumor formation in vivo, and induced a cell cycle transition from G0/G1 to S phase, whereas CDX2 overexpression inhibited cell proliferation. TOP/FOP-Flash reporter assay showed that CDX2 knockdown or CDX2 overexpression significantly increased or decreased Wnt signaling activity. Western blot assay showed that downstream targets of Wnt signaling, including β-catenin, cyclin D1 and c-myc, were up-regulated or down-regulated in CDX2-knockdown or CDX2-overexpressing colon cancer cells. In addition, suppression of Wnt signaling by XAV-939 led to a marked suppression of the cell proliferation enhanced by CDX2 knockdown, whereas activation of this signaling by CHIR-99021 significantly enhanced the cell proliferation inhibited by CDX2 overexpression. Dual-luciferase reporter and quantitative chromatin immunoprecipitation (qChIP) assays further confirmed that CDX2 transcriptionally activates glycogen synthase kinase-3β (GSK-3β) and axis inhibition protein 2 (Axin2) expression by directly binding to the promoter of GSK-3β and the upstream enhancer of Axin2. In conclusion, these results indicated that CDX2 inhibits the proliferation and tumor formation of colon cancer cells by suppressing Wnt/β-catenin signaling.

Inhibition of Wnt/β-catenin signaling suppresses myofibroblast differentiation of lung resident mesenchymal stem cells and pulmonary fibrosis

An emerging paradigm proposes a crucial role for lung resident mesenchymal stem cells (LR-MSCs) via a fibroblastic transdifferentiation event in the pathogenesis of idiopathic pulmonary fibrosis (IPF). Aberrant activation of Wnt/β-catenin signaling occurs in virtually all fibrotic lung diseases and is relevant to the differentiation of mesenchymal stem cells (MSCs). In vitro, by measuring the protein levels of several key components involved in Wnt/β-catenin signaling, we confirmed that this signaling pathway was activated in the myofibroblast differentiation of LR-MSCs. Targeted inhibition of Wnt/β-catenin signaling by a small molecule, ICG-001, dose-dependently impeded the proliferation and transforming growth factor-β1 (TGF-β1)-mediated fibrogenic actions of LR-MSCs. In vivo, ICG-001 exerted its lung protective effects after bleomycin treatment through blocking mesenchymal-myofibroblast transition, repressing matrix gene expression, and reducing cell apoptosis. Moreover, delayed administration of ICG-001 attenuated bleomycin-induced lung fibrosis, which may present a promising therapeutic strategy for intervention of IPF. Interestingly, these antifibrotic actions of ICG-001 are operated by a mechanism independent of any disruption of Smad activation. In conclusion, our study demonstrated that Wnt/β-catenin signaling may be an essential mechanism underlying the regulation of myofibroblast differentiation of LR-MSCs and their further participation in the development of pulmonary fibrosis.

Inhibition of Wnt/β-catenin signaling suppresses myofibroblast differentiation of lung resident mesenchymal stem cells and pulmonary fibrosis

An emerging paradigm proposes a crucial role for lung resident mesenchymal stem cells (LR-MSCs) via a fibroblastic transdifferentiation event in the pathogenesis of idiopathic pulmonary fibrosis (IPF). Aberrant activation of Wnt/β-catenin signaling occurs in virtually all fibrotic lung diseases and is relevant to the differentiation of mesenchymal stem cells (MSCs). In vitro, by measuring the protein levels of several key components involved in Wnt/β-catenin signaling, we confirmed that this signaling pathway was activated in the myofibroblast differentiation of LR-MSCs. Targeted inhibition of Wnt/β-catenin signaling by a small molecule, ICG-001, dose-dependently impeded the proliferation and transforming growth factor-β1 (TGF-β1)-mediated fibrogenic actions of LR-MSCs. In vivo, ICG-001 exerted its lung protective effects after bleomycin treatment through blocking mesenchymal-myofibroblast transition, repressing matrix gene expression, and reducing cell apoptosis. Moreover, delayed administration of ICG-001 attenuated bleomycin-induced lung fibrosis, which may present a promising therapeutic strategy for intervention of IPF. Interestingly, these antifibrotic actions of ICG-001 are operated by a mechanism independent of any disruption of Smad activation. In conclusion, our study demonstrated that Wnt/β-catenin signaling may be an essential mechanism underlying the regulation of myofibroblast differentiation of LR-MSCs and their further participation in the development of pulmonary fibrosis.

Downregulation of miR-3127-5p promotes epithelial-mesenchymal transition via FZD4 regulation of Wnt/β-catenin signaling in non-small-cell lung cancer

MiR-3127-5p has been implicated as a tumor-suppressive microRNA (miRNA) in non-small-cell lung cancer (NSCLC) and its expression was associated with tumor recurrence and poor prognosis. The aim of this study was to determine whether miR-3127-5p regulates epithelial-mesenchymal transition (EMT) in NSCLC, and to investigate the underlying mechanisms. Using qRT-PCR, we examined the expression levels of miR-3127-5p in a cohort of primary NSCLC specimens with and without distant metastasis. We further performed a series of in vitro and in vivo experiments to investigate the effects and underlying mechanism of miR-3127-5p on EMT, cell migration, invasion, and adhesion in NSCLC. We found that metastatic NSCLC tissues showed markedly downregulated miR-3127-5p expression. Transforming growth factor-β1 (TGF-β1) treatment induced EMT in A549 and H1299 cells, and downregulation of miR-3127-5p could result in the similar effect. Mechanically, we demonstrated that frizzled-4 (FZD4) is a target gene and miR-3127-5p exerts its effects by regulating the Wnt/β-catenin signaling. In addition, the expression levels of FZD4 and miR-3127-5p were also negatively associated in both clinical and xenografted tumors. Overall, these findings suggest that downregulation of miR-3127-5p promotes EMT through activating the Wnt/FZD4/β-catenin signaling pathway and may represent a therapeutic target for NSCLC metastasis.

Comprehensive assessment and meta-analysis of the association between CTNNB1 polymorphisms and cancer risk

CTNNB1, encoding β-catenin, is a well-known tumor-related gene in the wnt signaling pathway. It has been reported that CTNNB1 polymorphisms are associated with cancer risk. However, the data were inconsistent. In this article, we conducted a systematic review for the researches related to the association of single nucleotide polymorphisms (SNPs) in CTNNB1 with overall cancer risk. Meanwhile, a series of inclusion and exclusion criteria were set to select articles for quantitative analysis. Consequently, eight case-control studies containing 4388 cases and 4477 controls were included in a meta-analysis of four highly studied CTNNB1 SNPs (rs1798802 A/G, rs4135385 A/G, rs11564475 A/G, and rs2293303 C/T). The association between each SNP and cancer risk was estimated by calculating odds ratios (ORs) and their 95% confidence intervals (95%CIs). The results showed rs1798802 (AA compared with GG: P=0.044, OR=0.72) and rs2293303 (TT compared with CC: P=0.002, OR=2.86; recessive model: P=0.006, OR=2.91; T compared with C: P=0.004, OR=1.19) polymorphisms were associated with overall cancer risk. In stratified analysis, rs4135385 polymorphism was found to elevate the risk in Caucasian or in gastrointestinal cancer subgroup. Additionally, rs2293303 conferred to an increased cancer risk when the source of control groups was hospital-based (HB). In conclusion, the three CTNNB1 SNPs were suggested to have the potential to be novel biomarkers for risk prediction of cancer in overall population or some specific subgroups. Our study could provide research clues for further related investigations.

Molecular mechanisms involved in podocyte EMT and concomitant diabetic kidney diseases: an update

Epithelial–mesenchymal transition (EMT) is a tightly regulated process by which epithelial cells lose their hallmark epithelial characteristics and gain the features of mesenchymal cells. For podocytes, expression of nephrin, podocin, P-cadherin, and ZO-1 is downregulated, the slit diaphragm (SD) will be altered, and the actin cytoskeleton will be rearranged. Diabetes, especially hyperglycemia, has been demonstrated to incite podocyte EMT through several molecular mechanisms such as TGF-β/Smad classic pathway, Wnt/β-catenin signaling pathway, Integrins/integrin-linked kinase (ILK) signaling pathway, MAPKs signaling pathway, Jagged/Notch signaling pathway, and NF-κB signaling pathway. As one of the most fundamental prerequisites to develop ground-breaking therapeutic options to prevent the development and progression of diabetic kidney disease (DKD), a comprehensive understanding of the molecular mechanisms involved in the pathogenesis of podocyte EMT is compulsory. Therefore, the purpose of this paper is to update the research progress of these underlying signaling pathways and expound the podocyte EMT-related DKDs.

Inversin correlates with the malignant phenotype of non-small cell lung cancer and promotes the invasiveness of lung cancer cells

Inversin, encoded by NPHP2, is one of the 10 NPHP proteins known to be involved in nephronophthisis (an autosomal recessive cystic kidney). Although the previous reports showed that inversin played an important role in embryonic development and renal diseases, its function in cancer was not revealed clearly so far. As measured by immunohistochemical staining, inversin was highly expressed in the cytoplasm of lung cancer samples (63.4%, 161/254) compared with adjacent normal lung tissues (22.0%, 11/50, p < 0.01). Moreover, its expression was positively correlated with differentiation ( p = 0.014), tumor node metastasis staging ( p = 0.007), and lymph node metastasis ( p = 0.020). The overall survival of non-small cell lung cancer patients with inversin positive expression (45.41 ± 1.800 months) was significantly reduced compared with those with inversin negative expression (51.046 ± 2.238 months, p = 0.042). Consistently, we found that the invasion capacity of A549 cells transfected with inversin was significantly stronger than that of control cells ( p < 0.05), while inversin siRNA-treatment significantly reduced cell invasion in H1299 cells ( p < 0.05). Additionally, we demonstrated that inversin could upregulate the expression of N-cadherin, Vimentin, matrix metalloproteinase-2, and matrix metalloproteinase-9. Collectively, these results indicated that inversin might promote the tumorigenicity of lung cancer cells and serve as a novel therapeutic target of non-small cell lung cancer.

Functional Genomics Identifies Tis21-Dependent Mechanisms and Putative Cancer Drug Targets Underlying Medulloblastoma Shh-Type Development

We have recently generated a novel medulloblastoma (MB) mouse model with activation of the Shh pathway and lacking the MB suppressor Tis21 (Patched1^+/-/Tis21^KO ). Its main phenotype is a defect of migration of the cerebellar granule precursor cells (GCPs). By genomic analysis of GCPs in vivo, we identified as drug target and major responsible of this defect the down-regulation of the promigratory chemokine Cxcl3. Consequently, the GCPs remain longer in the cerebellum proliferative area, and the MB frequency is enhanced. Here, we further analyzed the genes deregulated in a Tis21-dependent manner (Patched1^+/-/Tis21 wild-type vs. Ptch1^+/-/Tis21 knockout), among which are a number of down-regulated tumor inhibitors and up-regulated tumor facilitators, focusing on pathways potentially involved in the tumorigenesis and on putative new drug targets. The data analysis using bioinformatic tools revealed: (i) a link between the Shh signaling and the Tis21-dependent impairment of the GCPs migration, through a Shh-dependent deregulation of the clathrin-mediated chemotaxis operating in the primary cilium through the Cxcl3-Cxcr2 axis; (ii) a possible lineage shift of Shh-type GCPs toward retinal precursor phenotype, i.e., the neural cell type involved in group 3 MB; (iii) the identification of a subset of putative drug targets for MB, involved, among the others, in the regulation of Hippo signaling and centrosome assembly. Finally, our findings define also the role of Tis21 in the regulation of gene expression, through epigenetic and RNA processing mechanisms, influencing the fate of the GCPs.

GalNAc-T14 promotes metastasis through Wnt dependent HOXB9 expression in lung adenocarcinoma

While metastasis, the main cause of lung cancer-related death, has been extensively studied, the underlying molecular mechanism remains unclear. A previous clinicogenomic study revealed that expression of N-acetylgalactosaminyltransferase (GalNAc-T14), is highly inversely correlated with recurrence-free survival in those with non-small cell lung cancer (NSCLC). However, the underlying molecular mechanism(s) has not been determined. Here, we showed that GalNAc-T14 expression was positively associated with the invasive phenotype. Microarray and biochemical analyses revealed that HOXB9, the expression of which was increased in a GalNAc-T14-dependent manner, played an important role in metastasis. GalNAc-T14 increased the sensitivity of the WNT response and increased the stability of the β-catenin protein, leading to induced expression of HOXB9 and acquisition of an invasive phenotype. Pharmacological inhibition of β-catenin in GalNAc-T14-expressing cancer cells suppressed HOXB9 expression and invasion. A meta-analysis of clinical genomics data revealed that expression of GalNAc-T14 or HOXB9 was strongly correlated with reduced recurrence-free survival and increased hazard risk, suggesting that targeting β-catenin within the GalNAc-T14/WNT/HOXB9 axis may be a novel therapeutic approach to inhibit metastasis in NSCLC.

Silencing MARCH1 suppresses proliferation, migration and invasion of ovarian cancer SKOV3 cells via downregulation of NF-κB and Wnt/β-catenin pathways

Membrane-associated RING-CH (MARCH) belongs to the family of RING-CH type E3 ubiquitin ligases. MARCH1 ubiquitinates and downregulates MHC class II expression in APCs and targets major players of the immune system. However, the role of MARCH1 in ovarian cancer has not been elucidated. The present study investigated the function of MARCH1 in ovarian cancer and the potential mechanisms involved. MARCH1 expression was examined in human ovarian cancer tissue specimens by immunohistochemistry. The role of MARCH1 in ovarian cancer cells was assessed by cell proliferation, migration and invasion assays with MARCH1 gene silencing. To investigate the mechanism by which MARCH1 functions, correlation between MARCH1 and the cell signaling pathways were analyzed using a luciferase reporter assay, real-time RT-PCR, western blot assay and immunofluorescence. MARCH1 was found to be overexpressed in ovarian cancer tissues when compared to adjacent non-tumor and normal ovarian tissues. Silencing MARCH1 inhibited SKOV3 cell proliferation, invasion and migration, as well as inhibiting the NF-κB and the Wnt/β-catenin pathways. MARCH1 functions as a tumor promoter by upregulating the NF-κB and the Wnt/β-catenin pathways, indicating that MARCH1 may be a therapeutic target for patients with ovarian cancer.

Identifying the Target Cells and Mechanisms of Merkel Cell Polyomavirus Infection

Infection with Merkel cell polyomavirus (MCPyV) can lead to Merkel cell carcinoma (MCC), a lethal form of skin cancer. However, the skin cell type productively infected by MCPyV remains a central question. We combined cell culture and ex vivo approaches to identify human dermal fibroblasts as natural host cells that support productive MCPyV infection. Based on this, we established a cell culture model for MCPyV infection, which will facilitate investigation of the oncogenic mechanisms for this DNA virus. Using this model, we discovered that induction of matrix metalloproteinase (MMP) genes by the WNT/β-catenin signaling pathway and other growth factors stimulates MCPyV infection. This suggests that MCC risk factors such as UV radiation and aging, which are known to stimulate WNT signaling and MMP expression, may promote viral infection and thus drive MCC. Our study also introduces the FDA-approved MEK antagonist trametinib as an effective inhibitor for controlling MCPyV infection.

β2-Adrenoceptor is involved in connective tissue remodeling in regenerating muscles by decreasing the activity of MMP-9

We investigated the role of β2-adrenoceptors in the connective tissue remodeling of regenerating muscles from β2-adrenoceptor knockout (β2KO) mice. Tibialis anterior muscles from β2KO mice were cryolesioned and analyzed after 3, 10, and 21 days. Regenerating muscles from β2KO mice showed a significant increase in the area density of the connective tissue and in the amount of collagen at 10 days compared with wild-type (WT) mice. A greater increase occurred in the expression levels of collagen I, III, and IV in regenerating muscles from β2KO mice evaluated at 10 days compared with WT mice; this increase continued at 21 days, except for collagen III. Matrix metalloproteinase (MMP-2) activity increased to a similar extent in regenerating muscles from both β2KO and WT mice at 3 and 10 days. This was also the case for MMP-9 activity in regenerating muscles from both β2KO and WT mice at 3 days; however, at 10 days post-cryolesion, this activity returned to baseline levels only in WT mice. MMP-3 activity was unaltered in regenerating muscles at 10 days. mRNA levels of tumor necrosis factor-α increased in regenerating muscles from WT and β2KO mice at 3 days and, at 10 days post-cryolesion, returned to baseline only in WT mice. mRNA levels of interleukin-6 increased in muscles from WT mice at 3 days post-cryolesion and returned to baseline at 10 days post-cryolesion but were unchanged in β2KO mice. Our results suggest that the β2-adrenoceptor contributes to collagen remodeling during muscle regeneration by decreasing MMP-9 activity.

Recombinant sFRP4 bound chitosan–alginate composite nanoparticles embedded with silver nanoclusters for Wnt/β-catenin targeting in cancer theranostics

Targeting a specific pathway aberrantly upregulated in cancer cells has shown immense potential in cancer therapy.

Matrix metalloproteinase 14 modulates signal transduction and angiogenesis in the cornea

The cornea is transparent and avascular, and retention of these characteristics is critical to maintaining vision clarity. Under normal conditions, wound healing in response to corneal injury occurs without the formation of new blood vessels; however, neovascularization may be induced during corneal wound healing when the balance between proangiogenic and antiangiogenic mediators is disrupted to favor angiogenesis. Matrix metalloproteinases (MMPs), which are key factors in extracellular matrix remodeling and angiogenesis, contribute to the maintenance of this balance, and in pathologic instances, can contribute to its disruption. Here, we elaborate on the facilitative role of MMPs, specifically MMP-14, in corneal neovascularization. MMP-14 is a transmembrane MMP that is critically involved in extracellular matrix proteolysis, exosome transport, and cellular migration and invasion, processes that are critical for angiogenesis. To aid in developing efficacious therapies that promote healing without neovascularization, it is important to understand and further investigate the complex pathways related to MMP-14 signaling, which can also involve vascular endothelial growth factor, basic fibroblast growth factor, Wnt/β-catenin, transforming growth factor, platelet-derived growth factor, hepatocyte growth factor or chemokines, epidermal growth factor, prostaglandin E2, thrombin, integrins, Notch, Toll-like receptors, PI3k/Akt, Src, RhoA/RhoA kinase, and extracellular signal-related kinase. The involvement and potential contribution of these signaling molecules or proteins in neovascularization are the focus of the present review.

Wnt/β-catenin signaling in bone marrow niche

The bone marrow (BM) niche is a specific physiological environment for hematopoietic and non-hematopoietic stem cells (HSCs). Several signaling pathways (including Wnt/β-catenin) regulate various aspects of stem cell growth, function and death in the BM niche. In addition, the canonical Wnt pathway is crucial for directing self-renewal and differentiation as important mechanisms in many types of stem cells. We review the role of the Wnt/β-catenin pathway in the BM niche and its importance in stem cells. Relevant literature was identified by a PubMed search (1997-2014) of English-language literature by using the following keywords: BM niche, Wnt/β-catenin signaling, osteoblast, osteoclast and bone disease. The Wnt/β-catenin pathway regulates the stability of the β-catenin proto-oncogene. The stabilized β-catenin then translocates to the nucleus, forming a β-catenin-TCF/LEF complex regulating the transcription of specific target genes. Stem cells require β-catenin to mediate their response to Wnt signaling for maintenance and transition from the pluripotent state during embryogenesis. In adult stem cells, Wnt signaling functions at various hierarchical levels to contribute to the specification of the diverse tissues. Aberrant Wnt/β-catenin signaling and its downstream transcriptional regulators are observed in several malignant stem cells and human cancers. Because Wnt signaling can maintain stem cells and cancer cells, the ability to modulate the Wnt pathway either positively or negatively may be of therapeutic relevance. The controlled activation of Wnt signaling might allow us to enhance stem and progenitor cell activity when regeneration is needed.

-148 C/T polymorphism of Axin2 contributes to a decreased risk of cancer: evidence from a meta-analysis

Several studies have reported an association between -148 C/T polymorphism of Axis inhibition protein 2 (Axin2) and cancer risk; however, the results are inconsistent. In this study, a meta-analysis was performed to assess the association between -148 C/T polymorphism of Axin2 and susceptibility to cancer. Published case-control and cohort-based studies from PubMed, Embase, Wanfang, and CNKI were retrieved, and data were manually extracted. The odds ratios (ORs) and 95% confidence intervals (CIs) of the included studies were pooled. Begg's and Egger's tests were used to evaluate publication bias. Cumulative and recursive cumulative meta-analyses (CMA) were performed as evidence accumulated to investigate the trends and stability of the effect size. Nine articles with 1,664 cases and 1,796 controls were included. The pooled effect size showed an association between -148 C/T polymorphism and the risk of cancer (dominant model, OR: 0.72, 95% CI: 0.63-0.83; allele model, OR: 0.81, 95% CI: 0.73-0.90). CMA showed an association trend, and the recursive CMA indicated that more evidence is needed to make conclusions about significance. In a subgroup analysis, a significant association between -148 C/T polymorphism and low cancer susceptibility was detected for lung cancer (dominant model, 0.69, 95% CI: 0.56-0.85; recessive model, OR: 0.75, 95% CI: 0.56-0.99; allele model, 0.76, 95% CI: 0.66-0.86). The -148 C/T polymorphism was also associated with low cancer susceptibility among Asians (dominant model, OR: 0.68, 95% CI: 0.57-0.81; recessive model, OR: 0.75, 95% CI: 0.56-0.99; allele model, OR: 0.76, 95% CI: 0.66-0.86). The Axin2 -148 C/T polymorphism was found to be significantly associated with a decreased risk of cancer, particularly lung cancer, in Asians and population-based controls. Thus, Axin2 should be considered as a potential therapeutic target for preventing tumor growth.

Quantitative assessment of the association between AXIN2 rs2240308 polymorphism and cancer risk

Axin2 is involved in the regulation of Wnt/β-catenin pathway and implicated in cancer development and progression. The association between AXIN2 rs2240308 polymorphism and cancer risk has been examined in several case-control studies, but the conclusions were conflicting. Here we performed a meta-analysis to evaluate the role of rs2240308 in cancer risk. A total of 8 studies were included in this meta-analysis (1559 cancer cases and 1503 controls). The pooled odds ratios (OR) and the 95% confidence intervals (CIs) were assessed to evaluate the association of the AXIN2 rs2240308 polymorphism with a susceptibility to cancer. A significantly decreased overall cancer risk was observed in the homozygous (TT vs. CC), heterozygous (CT vs. CC), dominant (CT+TT vs. CC) and allelic (T vs. C) models (P < 0.005), rather than that in the recessive (TT vs. CT+CC) model (P = 0.092). AXIN2 polymorphism rs2240308 was also associated with decreased cancer risk under all five models in lung cancer. However, AXIN2 rs2240308 polymorphism was not associated with cancer risk under any above model in Turkish population and under homozygous, heterozygous, recessive models in Japanese population. These findings indicate that AXIN2 rs2240308 polymorphism significantly and race-specifically correlates with decreased cancer risk.

ECM1 regulates tumor metastasis and CSC-like property through stabilization of β-catenin

Extracellular Matrix Protein 1 (ECM1) is a marker for tumorigenesis and is correlated with invasiveness and poor prognosis in various types of cancer. However, the functional role of ECM1 in cancer metastasis is unclear. Here, we detected high ECM1 level in breast cancer patient sera that was associated with recurrence of tumor. The modulation of ECM1 expression affected not only cell migration and invasion, but also sphere-forming ability and drug resistance in breast cancer cell lines. In addition, ECM1 regulated the gene expression associated with the epithelial to mesenchymal transition (EMT) progression and cancer stem cell (CSC) maintenance. Interestingly, ECM1 increased β-catenin expression at the post-translational level through induction of MUC1, which was physically associated with β-catenin. Indeed, the association between β-catenin and the MUC1 cytoplasmic tail was increased by ECM1. Furthermore, forced expression of β-catenin altered the gene expression that potentiated EMT progression and CSC phenotype maintenance in the cells. These data provide evidence that ECM1 has an important role in cancer metastasis through β-catenin stabilization.

FOXO3a modulates WNT/β-catenin signaling and suppresses epithelial-to-mesenchymal transition in prostate cancer cells

Emerging evidence has revealed a negative correlation between Forkhead box-O (FOXO) expression and prostate cancer grade and spread, indicating its role as a suppressor of prostate cancer metastasis. However, there is still incomplete understanding about the role of FOXO transcription factors in prostate cancer progression. In this investigation, we demonstrate that FOXO3a significantly inhibits the expression β-catenin in prostate cancer cells. The mechanism of inhibiting β-catenin expression involves the FOXO3a-mediated transactivated microRNA-34b/c, which consequently suppressed β-catenin mRNA expression by targeting the untranslated regions (UTRs) of β-catenin. Additionally, FOXO3a can directly bind to β-catenin, and competes with TCF for interaction with β-catenin, thereby inhibiting β-catenin/TCF transcriptional activity and reducing the expression of β-catenin target genes. Furthermore, prostate cancer cells expressing FOXO3a shRNAs display mesenchymal characteristics, including enhanced cell migration and differential regulation of the EMT markers, whereas knockdown of β-catenin results in reversal of shFOXO3a-mediated EMT phenotypic changes. Collectively, these observations demonstrated that FOXO3a inhibits malignant phenotypes that are dependent on β-catenin-dependent modulation of EMT-related genes, and provided fresh insight into the mechanisms by which a FOXO3a-miR-34b/c axis restrains canonical β-catenin signaling cascades in prostate cancer cell.

Expression of MTAP inhibits tumor-related phenotypes in HT1080 cells via a mechanism unrelated to its enzymatic function

Methylthioadenosine Phosphorylase (MTAP) is a tumor suppressor gene that is frequently deleted in human cancers and encodes an enzyme responsible for the catabolism of the polyamine byproduct 5′deoxy-5′-methylthioadenosine (MTA). To elucidate the mechanism by which MTAP inhibits tumor formation, we have reintroduced MTAP into MTAP-deleted HT1080 fibrosarcoma cells. Expression of MTAP resulted in a variety of phenotypes, including decreased colony formation in soft-agar, decreased migration, decreased in vitro invasion, increased matrix metalloproteinase production, and reduced ability to form tumors in severe combined immunodeficiency mice. Microarray analysis showed that MTAP affected the expression of genes involved in a variety of processes, including cell adhesion, extracellular matrix interaction, and cell signaling. Treatment of MTAP-expressing cells with a potent inhibitor of MTAP’s enzymatic activity (MT-DADMe-ImmA) did not result in a MTAP− phenotype. This finding suggests that MTAP’s tumor suppressor function is not the same as its known enzymatic function. To confirm this, we introduced a catalytically inactive version of MTAP, D220A, into HT1080 cells and found that this mutant was fully capable of reversing the soft agar colony formation, migration, and matrix metalloproteinase phenotypes. Our results show that MTAP affects cellular phenotypes in HT1080 cells in a manner that is independent of its known enzymatic activity.

S100A8/A9 regulates MMP-2 expression and invasion and migration by carcinoma cells

Intracellular calprotectin (S100A8/A9) functions in the control of the cell cycle checkpoint at G2/M. Dysregulation of S100A8/A9 appears to cause loss of the checkpoint, which frequently characterizes head and neck squamous cell carcinoma (HNSCC). In the present study, we analyzed carcinoma cells for other S100A8/A9-directed changes in malignant phenotype. Using a S100A8/A9-negative human carcinoma cell line (KB), transfection to express S100A8 and S100A9 caused selective down-regulation of MMP-2 and inhibited in vitro invasion and migration. Conversely, silencing of endogenous S100A8 and S100A9 expression in TR146 cells, a well-differentiated HNSCC cell line, increased MMP-2 activity and in vitro invasion and migration. When MMP-2 expression was silenced, cells appeared to assume a less malignant phenotype. To more closely model the architecture of cell growth in vivo, cells were grown in a 3D collagen substrate, which was compared to 2D. Growth on 3D substrates caused greater MMP-2 expression. Whereas hypermethylation of CpG islands occurs frequently in HNSCC, S100A8/A9-dependent regulation of MMP-2 could not be explained by modification of the upstream promoters of MMP2 or TIMP2. Collectively, these results suggest that intracellular S100A8/A9 contributes to the cancer cell phenotype by modulating MMP-2 expression and activity to regulate cell migration and mobility.

Significant association between the Axin2 rs2240308 single nucleotide polymorphism and the incidence of prostate cancer

The Wnt signaling pathway plays a crucial role in human cancer development, and axis inhibition protein 2 (Axin2) is a master scaffold protein involved in Wnt signaling. Axin2 negatively regulates Wnt signaling and acts as a tumor suppressor protein. The present study evaluated the association between the Axin2 single nucleotide polymorphism (SNP) rs2240308 [guanine (G)/adenine (A)] and the incidence of prostate cancer. In total, 103 patients with prostate cancer and 100 cancer-free control males were included in this case-control study, and were genotyped using the genomic DNA extracted from peripheral blood samples. The results revealed a higher incidence of prostate cancer in the subjects with the homozygous GG genotype and a reduced cancer incidence in the patients with the GA genotype of the rs2240308 SNP (G/A) in the Axin2 gene. The adjusted odds ratio for carriers with the GA genotype was 0.377 (95% CI, 0.206–0.688; P=0.001) and that for the AA genotype was 0.830 (95% CI, 0.309–2.232; P=0.712) compared with the GG genotype. Therefore, the GA genotype was found to exhibit a protective effect that decreased the risk of prostate cancer. To the best of our knowledge, this is the first study to demonstrate the significant association between this SNP (rs2240308, G/A) and the risk of prostate cancer. This association indicates the possibility that the variations in the Axin2 gene in this position may play a significant role in promoting the development of cancer in the prostate. We believe that the Axin2 SNP (rs2240308) could be a useful biomarker for the predisposition and early diagnosis of the disease.

SCF increases cardiac stem cell migration through PI3K/AKT and MMP‑2/‑9 signaling

The transplantation of cardiac stem cells (CSCs) is thought to be responsible for improving the performance of injured heart induced by myocardial infarction (MI). However, the mechanisms involved in the migration of activated CSCs post-MI remain to be clarified. In this study, CSCs were isolated from rat hearts and a cellular migration assay was performed using a 24-well Transwell system. Stem cell factor (SCF) induced CSC migration in a concentration-dependent manner, which could be blocked with an SCF antibody as well as a PI3K/AKT inhibitor, LY294002. Moreover, SCF induced the expression and activity of matrix metalloproteinase (MMP)-2 and MMP-9 in a concentration- and time-dependent manner, as measured by quantitative RT-PCR, western blot analysis and gelatin zymography. Results of western blot analysis revealed phosphorylated AKT was markedly increased in SCF-treated CSCs and that inhibition of SCF/c-Kit signaling or phospho-AKT activity significantly attenuated the SCF-induced expression of MMP-2 and MMP-9. Thus, our results showed that SCF partially mediated CSC migration via the activation of PI3K/AKT/MMP-2/-9 signaling.

Identification of a novel role of ZMIZ2 protein in regulating the activity of the Wnt/β-catenin signaling pathway

ZMIZ2, also named ZIMP7, is a protein inhibitor of activated STAT (PIAS)-like protein and a transcriptional coactivator. In this study, we investigated the interaction between ZMIZ2 and β-catenin, a key regulator of the Wnt signaling pathway. We demonstrated that the expression of exogenous ZMIZ2 augments TCF (T cell factor) and β-catenin-mediated transcription. In contrast, shRNA knockdown of ZMIZ2 expression specifically represses the enhancement of TCF/β-catenin-mediated transcription by ZMIZ2. Using Wnt3a-conditioned medium, we demonstrated that ZMIZ2 can enhance Wnt ligand-induced TCF/β-catenin-mediated transcription. We also showed a promotional role of ZMIZ2 in enhancing β-catenin downstream target gene expression in human cells and in Zmiz2 null (Zmiz2(-/-)) mouse embryonic fibroblasts (MEFs). The regulatory role of Zmiz2 in Wnt-induced TCF/β-catenin-mediated transcription can be restored in Zmiz2(-/-) MEFs that were infected with adenoviral expression vectors for Zmiz2. Moreover, enhancement of Zmiz2 on TCF/β-catenin-mediated transcription was further demonstrated in Zmiz2 knockout and Axin2 reporter compound mice. Furthermore, the protein-protein interaction between ZMIZ2 and β-catenin was identified by co-immunoprecipitation and in vitro protein pulldown assays. We also observed recruitment of endogenous ZMIZ2 onto the promoter region of the Axin 2 gene, a β-catenin downstream target promoter, in a Wnt ligand-inducible manner. Finally, a promotional role of ZMIZ2 on cell growth was demonstrated in human cell lines and Zmiz2 knockout MEFs. Our findings demonstrate a novel interaction between ZMIZ2 and β-catenin and elucidate a novel mechanism for PIAS-like proteins in regulating Wnt signaling pathways.

Glucose transporter-1 expression in CD133+ laryngeal carcinoma Hep-2 cells

CD133 is a useful putative marker of cancer stem cells (CSCs) in human laryngeal tumors. Numerous studies have demonstrated that CD133+ CSCs possess higher clonogenicity, invasiveness and tumorigenesis compared with CD133- cells. Recently, interest in the Warburg effect in the microenvironment of CSCs has escalated. The Warburg effect dictates that cancer cells rely on glycolysis rather than oxidative phosphorylation under aerobic conditions. In numerous cancer cells, glucose is used mainly for the glycolytic pathway. Stem cells express high levels of glycolytic enzymes and rely mostly on glycolysis to meet their energy demands. Glucose is transported through cell membranes by glucose transporters (Glut). Studies of Glut-1 expression in CSCs are limited. In the present study, we investigated the proliferation of CD133+ Hep-2 cells and whether Glut-1 is expressed in laryngeal carcinoma CD133+ Hep-2 cells. Real-time reverse transcription-polymerase chain reaction (RT-PCR) demonstrated that the size of the CD133 product was 213 bp. Dissociation curve analysis demonstrated only the expected peaks at 82.1˚C for CD133. The mean ΔCt of CD133 expression was 10.98. Prior to isolation, the CD133+ fraction was 1.2% by fluorescence-activated cell sorting (FACS) analysis. Following isolation, the CD133+ fraction was increased to 76.1%. Successive tests also demonstrated that cells grew well following isolation. The proliferation of CD133+ and CD133- cells was not different during the first 3 days (P>0.05). From day 4, the proliferation capacity of CD133+ cells in vitro was higher than that of CD133- cells (P<0.05). The mean ΔCt of Glut-1 mRNA expression was 1.78 for CD133+ cells and 1.00 for CD133- cells (P<0.05). The mean Glut-1 protein values in CD133+ and CD133- Hep-2 cells relative to β-tubulin were 0.48 ± 0.02 and 0.21 ± 0.03 (µg/µl), respectively (P<0.05). In conclusion, CD133+ cells demonstrated higher proliferation. Glut-1 mRNA and protein levels were higher in CD133+ than in CD133- cells. Our results suggest that Glut-1 is important in the energy supply of laryngeal CD133+ Hep-2 cells and Glut-1 may represent a potential therapeutic target for the inhibition of the proliferation of laryngeal CSCs.

MMP inhibition as a potential method to augment the healing of skeletal muscle and tendon extracellular matrix

The extracellular matrix (ECM) of skeletal muscle and tendon is composed of different types of collagen molecules that play important roles in the transmission of forces throughout the body, and in the repair and regeneration of injured tissues. Fibroblasts are the primary cells in muscle and tendon that maintain, repair, and modify the ECM in response to mechanical loading, injury, and inactivity. Matrix metalloproteinases (MMPs) are enzymes that digest collagen and other structural molecules, which are synthesized and excreted by fibroblasts. MMPs are required for baseline ECM homeostasis, but disruption of MMP regulation due to injury or disease can alter the normal ECM architecture and prevent proper force transmission. Chronic injuries and diseases of muscles and tendons can be severely debilitating, and current therapeutic modalities to enhance healing are quite limited. This review will discuss the mechanobiology of MMPs, and the potential use of MMP inhibitors to improve the treatment of injured and diseased skeletal muscle and tendon tissue.

Epithelial-mesenchymal Transition---A Hallmark of Breast Cancer Metastasis

Epithelial-mesenchymal transition (EMT) is a highly conserved cellular program that converts polarized, immotile epithelial cells to migratory mesenchymal cells. In addition, EMT was initially recognized as a key step for morphogenesis during embryonic development. Emerging evidences indicate that this important developmental program promotes metastasis, drug resistance, and tumor recurrence, features that are associated with a poor clinical outcome for patients with breast cancer. Therefore, better understanding of regulation and signaling pathways in EMT is essential to develop novel targeted therapeutics. In this review, we present updated developments underlying EMT in tumor progression and metastasis, and discuss the challenges remaining in breast cancer research.

Reprogramming adult Schwann cells to stem cell-like cells by leprosy bacilli promotes dissemination of infection

Differentiated cells possess a remarkable genomic plasticity that can be manipulated to reverse or change developmental commitments. Here, we show that the leprosy bacterium hijacks this property to reprogram adult Schwann cells, its preferred host niche, to a stage of progenitor/stem-like cells (pSLC) of mesenchymal trait by downregulating Schwann cell lineage/differentiation-associated genes and upregulating genes mostly of mesoderm development. Reprogramming accompanies epigenetic changes and renders infected cells highly plastic, migratory, and immunomodulatory. We provide evidence that acquisition of these properties by pSLC promotes bacterial spread by two distinct mechanisms: direct differentiation to mesenchymal tissues, including skeletal and smooth muscles, and formation of granuloma-like structures and subsequent release of bacteria-laden macrophages. These findings support a model of host cell reprogramming in which a bacterial pathogen uses the plasticity of its cellular niche for promoting dissemination of infection and provide an unexpected link between cellular reprogramming and host-pathogen interaction.

TLR2 enhances ovarian cancer stem cell self-renewal and promotes tumor repair and recurrence

Primary ovarian cancer is responsive to treatment, but chemoresistant recurrent disease ensues in majority of patients. Recent compelling evidence demonstrates that a specific population of cancer cells, the cancer stem cells, initiates and sustains tumors. It is therefore possible that this cell population is also responsible for recurrence. We have shown previously that CD44+/MyD88+ epithelial ovarian cancer stem cells (CD44+/MyD88+ EOC stem cells) are responsible for tumor initiation. In this study, we demonstrate that this population drives tumor repair following surgery- and chemotherapy-induced tumor injury. Using in vivo and in vitro models, we also demonstrate that during the process of tumor repair, CD44+/MyD88+ EOC stem cells undergo self-renewal as evidenced by upregulation of stemness-associated genes. More importantly, we show that a pro-inflammatory microenvironment created by the TLR2-MyD88-NFκB pathway supports EOC stem cell-driven repair and self-renewal. Overall, our findings point to a specific cancer cell population, the CD44+/MyD88+ EOC stem cells and a specific pro-inflammatory pathway, the TLR2-MyD88-NFκB pathway, as two of the required players promoting tumor repair, which is associated with enhanced cancer stem cell load. Identification of these key players is the first step in elucidating the steps necessary to prevent recurrence in EOC patients.

Epithelial-mesenchymal transition in breast cancer progression and metastasis

Breast cancer is the most common cancer in women, and approximately 90% of breast cancer deaths are caused by local invasion and distant metastasis of tumor cells. Epithelial-mesenchymal transition (EMT) is a vital process for large-scale cell movement during morphogenesis at the time of embryonic development. Tumor cells usurp this developmental program to execute the multi-step process of tumorigenesis and metastasis. Several transcription factors and signals are involved in these events. In this review, we summarize recent advances in breast cancer researches that have provided new insights in the molecular mechanisms underlying EMT regulation during breast cancer progression and metastasis. We especially focus on the molecular pathways that control EMT.

Migration of human mesenchymal stem cells under low shear stress mediated by mitogen-activated protein kinase signaling

Human mesenchymal stem cells (hMSCs) are attractive candidates for cell-based tissue repair approaches and have been used as vectors for delivering therapeutic genes to sites of injury. It is believed that hMSCs are able to detect and respond to shear stress due to blood and interstitial fluid flow through mechanotransduction pathways after transplantation. However, information regarding hMSC migration under shear stress and its mechanism is still limited. In this study, we examined the effect of shear stress on hMSC migration and the role of mitogen-activated protein kinases (MAPKs) in their migration. Shear stress between 0.2 and 10 Pa, which was produced by the flow medium, was exerted on fluorescently labeled hMSCs. Cell migration was evaluated using the scratch wound assay, and images were captured using a microscope equipped with a digital 3CCD camera. The results showed that hMSCs subjected to a shear stress of 0.2 Pa caused notably faster wound closure than statically cultured hMSCs, while migration in the 0.5- and 1-Pa shear stress group did not differ significantly from that in the control group. Shear stress >2 Pa markedly inhibited hMSC migration. hMSCs subjected to a shear stress of 0.2 Pa displayed an increase in extracellular signal-regulated kinases 1/2 (ERK1/2), c-Jun N-terminal kinases (JNK), and p38 MAPK activation for up to 60 min, while a shear stress of 2 Pa abrogated the activation. JNK and p38 MAPK inhibitors completely abolished the effect of shear stress on hMSC migration, while significant differences were observed between the ERK1/2 inhibitor-treated static control and shear stress groups. Taken together, these results demonstrate that low shear stress effectively induces hMSC migration and that JNK and p38 MAPK play more prominent roles in shear stress-induced migration than ERK1/2.

Significance of epithelial growth factor in the epithelial-mesenchymal transition of human gallbladder cancer cells

Five gallbladder cancer (GBC) cell lines were examined for morphological changes in collagen gel culture. GBh3 and HUCCT-1 cells formed tubules in response to treatment with epithelial growth factor (EGF) and hepatocyte growth factor (HGF), and showed high levels of expression of E-cadherin (ECD), and low levels of SNAIL, vimentin, transforming growth factor (TGF)-β, and nucleostemin (NS). In contrast, the GBd15 and FU-GBC-1 cell lines treated with EGF and HGF showed a scattering phenotype, and expressed low levels of ECD and high levels of SNAIL, vimentin, TGF-β, and NS. All cell lines expressed the EGF receptor, c-Met, EGF, and TGF-α, but not HGF. Transforming growth factor-β was upregulated by EGF. Knockdown of the EGF receptor abrogated both tubule formation and scattering, whereas KD of TGF-β abrogated only scattering. Knockdown of EGF induced nuclear translocation of β-catenin and Wnt-related NS induction in the scattering cell lines, but not in the tubule-forming cell lines, whereas KD of glycogen synthase kinase-3β in the tubule-forming cell lines resulted in the nuclear translocation of β-catenin and Wnt-related NS induction in response to EGF treatment. These results suggest that EGF enhances epithelial-mesenchymal transformation and acquisition of stemness in GBC cells with a scattering phenotype through the activity of β-catenin. Repression of ECD in scattering GBC cells induced the release of β-catenin from the cell adhesion complexes along the plasma membrane and its translocation to the nucleus to activate Wnt signaling, which upregulated NS.

Regulation of stem cell plasticity: mechanisms and relevance to tissue biology and cancer

Embryonic stem cells (ESCs) are associated with a high degree of plasticity, which allows them to self-renew and differentiate into every somatic cell. During differentiation, ESCs follow a hierarchically organized pattern towards tissue specificity, which ultimately results in permanent cell cycle arrest and a loss of cellular plasticity. In contrast to their normal somatic counterparts, cancer cells retain elevated levels of plasticity that include switches between epithelial and mesenchymal phenotypes. Transitions between these cell stages have lately been linked to the reacquisition of stem cell features during cellular reprogramming and dedifferentiation in normal and neoplastic cells. In this review, we discuss the key factors and their interplay that is needed to regain a stem cell stage with a particular emphasis put on the impact of cell cycle regulation. Apart from mechanistic insights into the emerging fundamental processes of stem cell plasticity and capacity to transdifferentiate, we also highlight implications of these concepts for tissue biology, tumorigenesis, and cancer therapy.

Multipotent mesenchymal stromal cells: clinical applications and cancer modeling

The recognition of the therapeutic potential of Multipotent Mesenchymal Stromal Cells (MSCs) is one of the most exciting recent advances in cell therapy. In just ten years, since the description of the multilineage potential of MSCs by Pittenger et al in 1999 until now, MSCs are being used in more than 150 clinical trials as therapeutic agents. The potential of these cells for cell-based therapies relies on several key properties: (1) their capacity to differentiate into several cell lineages; (2) their lack of immunogenicity and their immunomodulatory properties; (3) their ex vivo expansion potential; (4) their ability to secrete soluble factors which regulate crucial biological functions such as proliferation and differentiation over a broad spectrum of target cells; and (5) their ability to home to damaged tissues and tumor sites. Based on these properties MSCs are being exploited worldwide for a wide range of potential clinical applications including cell replacement strategies, treatment of graft-versus-host disease, autoimmune diseases and rejection after solid organ transplantation as well as their use as vehicles to deliver anti-cancer therapies. Importantly, the low inherent immunogenicity of MSCs means that they could be used not only for autologous but also for allogeneic cell therapies. In addition, increasing evidence has revealed a complex relationship between MSCs and cancer. Thus, solid evidence has placed MSCs transformed with specific mutations as the most likely cell of origin for certain sarcomas, and MSCs have been reported to both, inhibit or promote tumor growth depending on yet undefined conditions. Here we will thoroughly discuss the different potential clinical applications of MSC as well as the role of MSCs on sarcomagenesis and the control of tumor growth.