Retracted: Targeting of SPP1 by microRNA-340 inhibits gastric cancer cell epithelial–mesenchymal transition through inhibition of the PI3K/AKT signaling pathway

Gastric cancer (GC) is a common heterogeneous disease. The critical roles of microRNA-340 (miR-340) in the development and progression of GC were emphasized in accumulating studies. This study aims to examine the regulatory mechanism of miR-340 in GC cellular processes. Initially, microarray technology was used to identify differentially expressed genes and regulatory miRs in GC. After that, the potential role of miR-340 in GC was determined via ectopic expression, depletion, and reporter assay experiments. Expression of secreted phosphoprotein 1 (SPP1), miR-340, phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathway, and epithelial–mesenchymal transition (EMT)-related genes was measured. Moreover, to further explore the function of miR-340 in vivo and in vitro, proliferation, apoptosis, migration, invasion, and tumorigenic capacity were evaluated. SPP1 was a target gene of miR-340 which could then mediate the PI3K/AKT signaling pathway by targeting SPP1 in GC. Furthermore, miR-340 levels were reduced and SPP1 was enriched in GC tissues and cells, with the PI3K/AKT signaling pathway being activated. Inhibitory effects of upregulated miR-340 on SPP1 and the PI3K/AKT signaling pathway were confirmed in vivo and in vitro. Overexpression of miR-340 or the silencing of SPP1 inhibited GC cell proliferation, invasion, migration, and EMT process, but promoted apoptosis of GC cells. Typically, targeting of SPP1 by miR-340 may contribute to the inhibition of proliferation, migration, invasion, and EMT of GC cells via suppression of PI3K/AKT signaling pathway.     

Nigericin inhibits epithelial ovarian cancer metastasis by suppressing the cell cycle and epithelial−mesenchymal transition

Epithelial ovarian cancer (EOC) has the highest mortality among various types of gynecological malignancies. Most patients die of metastasis and recurrence due to cisplatin resistance. Thus, it is urgent to develop novel therapies to cure this disease. CCK-8 assay showed that nigericin exhibited strong cytotoxicity on A2780 and SKOV3 cell lines. Flow cytometry indicated that nigericin could induce cell cycle arrest at G0/G1 phase and promote cell apoptosis. Boyden chamber assay revealed that nigericin could inhibit migration and invasion in a dose-dependent manner by suppressing epithelial–mesenchymal transition (EMT) in EOC cells. These effects were mediated, at least partly, by the Wnt/β-catenin signaling pathway. Our results demonstrated that nigericin could inhibit EMT during cell invasion and metastasis through the canonical Wnt/β-catenin signaling pathway. Nigericin may prove to be a novel therapeutic strategy that is effective in patients with metastatic EOC.     

RNA-binding protein Dnd1 inhibits epithelial–mesenchymal transition and cancer stem cell-related traits on hepatocellular carcinoma cells

Objectives

To investigate the roles of Dead end 1 (Dnd1) in modulating cancer stem cell-related traits of hepatocellular carcinoma (HCC).

Results

Dead end (Dnd1) inhibited spheroid formation, suppressed the expression of stemness-related genes, and increased sensitivity to sorafenib in HCC cells. Mechanistically, Dnd1 could bind to 3′-UTR of LATS2, the key kinase of Hippo pathway, thus elevating LATS2 mRNA stability and its expression, subsequently leading to phosphorylation of YAP and its cytoplasmic retention. As a result, epithelial–mesenchymal transition (EMT) was weakened and therefore the generation of HCC stem cell properties was suppressed.

Conclusions

Dnd1 functions as a tumor suppressor by prohibiting CSC-like characteristics via activating Hippo pathway in HCC cells. Dnd1 could thus be a novel therapeutic target for HCC patients.

     

TGF-β1 regulates cell fate during epithelial–mesenchymal transition by upregulating survivin

Members of the transforming growth factor beta (TGF-β) superfamily are multifunctional cytokines that regulate several cellular processes, including cell cycle arrest, differentiation, morphogenesis, and apoptosis. TGF-β promotes extracellular matrix production and morphological change. Morphogenetic responses to TGF-β include cell migration and epithelial–mesenchymal transition (EMT), which are critical during embryogenesis, development of fibrotic diseases, and the spreading of advanced carcinomas. The purpose of this study was to clarify how TGF-β regulates the fate of retinal pigment epithelial (RPE) cells. TGF-β1 promoted cell cycle progression and phosphorylation of retinoblastoma protein (Rb) in ARPE-19 cells. TGF-β1 induced survivin expression, which in turn stabilized tubulin and Aurora B. RT-PCR and western blot analysis revealed that survivin expression increased in ARPE-19 cells following TGF-β1 treatment. When survivin was depleted, TGF-β1 induced cell cycle arrest and apoptosis and also reduced Rb phosphorylation. In conclusion, the present study shows that induction of EMT in human RPE cells upregulates survivin, leading to survivin-dependent inhibition of cell cycle arrest and apoptosis. Whether cells undergo EMT or apoptosis in response to TGF-β1 is dependent on their cell cycle state, and TGF-β1 regulates the cell cycle via survivin.     

Protocadherin 9 inhibits epithelial–mesenchymal transition and cell migration through activating GSK-3β in hepatocellular carcinoma

Protocadherin 9 (PCDH9) was found frequently lost in hepatocellular carcinoma (HCC). Here we investigated the role of PCDH9 in the development of HCC. We confirmed that PCDH9 was down-regulated in HCC tissues and cell lines compared with the adjacent non-tumor tissues. PCDH9 downregulation was significantly associated with malignant portal vein invasion of HCC patients. Gain- and loss-of-function studies revealed that downregulation of PCDH9 facilitated tumor cell migration and epithelial–mesenchymal transition (EMT). We identified PCDH9 as a novel regulator of EMT by increasing the activity of GSK-3β and inhibiting Snail1, indicating its potential therapeutic value for reducing metastasis of HCC.     

Role of fucosyltransferase IV in epithelial–mesenchymal transition in breast cancer cells

Epithelial–mesenchymal transition (EMT) is a crucial step in tumor progression and has an important role during cancer invasion and metastasis. Although fucosyltransferase IV (FUT4) has been implicated in the modulation of cell migration, invasion and cancer metastasis, its role during EMT is unclear. This study explores the molecular mechanisms of the involvement of FUT4 in EMT in breast cancer cells. Breast cancer cell lines display increased expression of FUT4, which is accompanied by enhanced appearance of the mesenchymal phenotype and which can be reversed by knockdown of endogenous FUT4. Moreover, FUT4 induced activation of phosphatidylinositol 3-kinase (PI3K)/Akt, and inactivation of GSK3β and nuclear translocation of NF-κB, resulting in increased Snail and MMP-9 expression and greater cell motility. Taken together, these findings indicate that FUT4 has a role in EMT through activation of the PI3K/Akt and NF-κB signaling systems, which induce the key mediators Snail and MMP-9 and facilitate the acquisition of a mesenchymal phenotype. Our findings support the possibility that FUT4 is a novel regulator of EMT in breast cancer cells and a promising target for cancer therapy.     

Amnion-derived mesenchymal stromal cells show a mesenchymal–epithelial phenotype in culture

The amnionic membrane is a rich source of multipotent mesenchymal stromal cells (hAMSC), which are readily available and show a potential use in regenerative medicine and tissue engineering. Before these cells can be applied clinically, careful characterization is necessary, especially as primary cells are known to change their phenotype in culture. We analyzed the mesenchymal phenotype of hAMSC at different stages after isolation using immunohistochemistry. Shortly after isolation (1 day), 92 % (±7 %) of the hAMSC expressed the mesenchymal marker vimentin, 2 % (±1 %) stained for the epithelial marker cytokeratin-7 and 5 % (±4 %) co-expressed these markers. After 5 days, the double positive cells slightly increased to 7 % (±3 %), while exclusive expression of cytokeratin-7 or vimentin remained unchanged (1 % ± 2 % and 92 % ± 1 %, respectively). After the first passage, all attached cells were vimentin-positive, while 54 % (±9 %) co-expressed cytokeratin-7 and vimentin. Thus, we conclude that under culture, hAMSC adopt a hybrid mesenchymal–epithelial phenotype. It is also essential to perform microscopical examination during the first days after isolation to detect contaminations with human amnion-derived epithelial cells in cultures of hAMSC.     

Extracellular matrix proteins regulate epithelial–mesenchymal transition in mammary epithelial cells

Mouse mammary epithelial cells undergo transdifferentiation via epithelial–mesenchymal transition (EMT) upon treatment with matrix metalloproteinase-3 (MMP3). In rigid microenvironments, MMP3 upregulates expression of Rac1b, which translocates to the cell membrane to promote induction of reactive oxygen species and EMT. Here we examine the role of the extracellular matrix (ECM) in this process. Our data show that the basement membrane protein laminin suppresses the EMT response in MMP3-treated cells, whereas fibronectin promotes EMT. These ECM proteins regulate EMT via interactions with their specific integrin receptors. α6-integrin sequesters Rac1b from the membrane and is required for inhibition of EMT by laminin. In contrast, α5-integrin maintains Rac1b at the membrane and is required for the promotion of EMT by fibronectin. Understanding the regulatory role of the ECM will provide insight into mechanisms underlying normal and pathological development of the mammary gland.     

Helicobacter pylori infection of gastrointestinal epithelial cells in vitro induces mesenchymal stem cell migration through an NF-κB-dependent pathway

The role of bone marrow-derived mesenchymal stem cells (MSC) in the physiology of the gastrointestinal tract epithelium is currently not well established. These cells can be recruited in response to inflammation due to epithelial damage, home, and participate in tissue repair. In addition, in the case of tissue repair failure, these cells could transform and be at the origin of carcinomas. However, the chemoattractant molecules responsible for MSC recruitment and migration in response to epithelial damage, and particularly to Helicobacter pylori infection, remain unknown although the role of some chemokines has been suggested. This work aimed to get insight into the mechanisms of mouse MSC migration during in vitro infection of mouse gastrointestinal epithelial cells by H. pylori. Using a cell culture insert system, we showed that infection of gastrointestinal epithelial cells by different H. pylori strains is able to stimulate the migration of MSC. This mechanism involves the secretion by infected epithelial cells of multiple cytokines, with a major role of TNFα, mainly via a Nuclear Factor-kappa B-dependent pathway. This study provides the first evidence of the role of H. pylori infection in MSC migration and paves the way to a better understanding of the role of bone marrow-derived stem cells in gastric pathophysiology and carcinogenesis.     

Chidamide alleviates TGF-β-induced epithelial–mesenchymal transition in lung cancer cell lines

Transforming growth factor-β (TGF-β)-induced epithelial–mesenchymal transition is a critical process in the initiation of metastasis of various types of cancer. Chidamide is a class I histone deacetylase inhibitor with anti-tumor activity. This study investigated the effects of chidamide on TGF-β-mediated suppression of E-cadherin expression in adenocarcinomic lung epithelial cells and the molecular mechanisms involved in these effects. Western blot analysis, confocal microscopy, Quantitative methyl-specific PCR and bisulfite sequencing were used to evaluate the effects of different treatments on chidamide ameliorating TGF-β induced-E-cadherin loss. H3 acetylation binding to the promoter of E-cadherin was detected by chromatin immunoprecipitations (CHIP). We found that chidamide reduced the level of lung cancer cell migration observed using a Boyden chamber assay (as an indicator of metastatic potential). Chidamide inhibited TGF-β-induced SMAD2 phosphorylation and attenuated TGF-β-induced loss of E-cadherin expression in lung cancer cells by Western blotting and confocal microscopy, respectively. Quantitative methyl-specific PCR and bisulfite sequencing revealed that TGF-β-enhanced E-cadherin promoter methylation was ameliorated in cells treated with chidamide. We demonstrated that histone H3 deacetylation within the E-cadherin promoter was required for TGF-β-induced E-cadherin loss; cell treatment with chidamide increased the H3 acetylation detected by CHIP. Taken together, our results demonstrate that TGF-β suppressed E-cadherin expression by regulating promoter methylation and histone H3 acetylation. Chidamide significantly enhanced E-cadherin expression in TGF-β-treated cells and inhibited lung cancer cell migration. These findings indicate that chidamide has a potential therapeutic use due to its capacity to prevent cancer cell metastasis.     

β5 integrin orchestrates epithelial mesenchymal transition in breast cancer

Comment on: Bianchi A, et al. Cell Cycle 2010; Volume 9, Issue 8.     

GPX2 silencing relieves epithelial–mesenchymal transition,invasion, and metastasis in pancreatic cancer by downregulating Wnt pathway

Glutathione peroxidase 2 (GPX2) participates in many cancers including pancreatic cancer (PC), and overexpression of GPX2 promotes tumor growth. Herein, we identified the role of GPX2 in epithelial–mesenchymal transformation (EMT), invasion, and metastasis in PC. Bioinformatics prediction was applied to select PC-related genes. The regulatory function of GPX2 in PC was explored by treatment with short hairpin RNA against GPX2 or LiCl (activator of wingless-type MMTV integration site [Wnt] pathway) in PC cells. GPX2 level in PC tissues, the levels of GPX2, β-catenin, Vimentin, Snail, epithelial-cadherin (E-cadherin), matrix metalloproteinase 2 (MMP2), MMP9, and Wnt2 in cells were determined. Subsequently, cell proliferation, invasion, and metastasis were assayed. Bioinformatics analysis revealed that GPX2 was involved in PC development mediated by the Wnt pathway. GPX2 was highly expressed in PC tissues. GPX2 silencing downregulated levels of β-catenin, Vimentin, Snail, MMP2, MMP9, and Wnt2 but upregulated levels of E-cadherin. It was confirmed that GPX2 silencing suppressed PC cell proliferation, metastasis, and invasion. Furthermore, the trend of EMT and invasion and metastasis of PC induced by the LiCl-activated Wnt pathway was reversed when the GPX2 was silenced. GPX2 silencing could inhibit the Wnt pathway, subsequently suppress PC development.     

AMD3100 inhibits epithelial–mesenchymal transition,cell invasion,and metastasis in the liver and the lung through blocking the SDF-1α/CXCR4 signaling pathway in prostate cancer

Stromal cell-derived factor-1 (SDF-1) and CXC chemokine receptor 4 (CXCR4) have been found to be tightly correlated with the progression of prostate cancer (PC). In this study, we investigated the effects of an SDF-1α/CXCR4 inhibitor, AMD3100, on cell progression and metastasis potential of human PC cells. Human PC cell lines (LNCaP, PC3, and DU145) were cultured to detect SDF-1α/CXCR4, which showed higher SDF-1α and CXCR4 expression than the normal human prostate epithelial cell line, RWPE-1. AMD3100 was confirmed to be an inhibitor of SDF-1α, and to detect the effect of SDF-1α/CXCR4 inhibition on PC, PC cells were treated with AMD3100 or/and CXCR4 siRNA. The results suggested that inhibition of the SDF-1α/CXCR4 pathway could promote the E-cadherin level but inhibit the levels of invasion and migration of vimentin, N-cadherin and α5β1 integrin. Finally, tumor formation in nude mice was conducted, and the cell experiment results were verfied. These data show that AMD3100 suppresses epithelial–mesenchymal transition and migration of PC cells by inhibiting the SDF-1α/CXCR4 signaling pathway, which provides a clinical target in the treatment of PC.