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AKT1

epithelial-mesenchymal transition (EMT) is an important process during development and oncogenesis by which epithelial cells acquire fibroblast-like properties and show reduced intercellular adhesion and increased motility. Squamous cell carcinoma lines engineered to express constitutively active Akt underwent EMT, characterized by down-regulation of the epithelial markers desmoplakin, E-cadherin, and beta-catenin and up-regulation of the mesenchymal marker vimentin. The cells lost epithelial cell morphology and acquired fibroblast-like properties. Additionally, E-cadherin was down-regulated transcriptionally. The cells expressing constitutively active Akt exhibited reduced cell-cell adhesion, increased motility on fibronectin-coated surfaces, and increased invasiveness in animals. AKT is activated in many human carcinomas, and the AKT-driven EMT may confer the motility required for tissue invasion and metastasis. These findings suggest that future therapies based on AKT inhibition may complement conventional treatments by controlling tumor cell invasion and metastasis.

Hypoxia activates genetic programs that facilitate cell survival; however, in cancer, it may promote invasion and metastasis. Although the exact mechanisms driving hypoxia-induced invasion and metastasis remain elusive, we hypothesized that epithelial-mesenchymal transition (EMT) may play a major role. We investigated this in vitro by treating hepatocellular carcinoma cells under 1.0% O(2). After the hypoxia treatment, the cells exhibited some morphological changes including cell elongation, cytoskeletal rearrangement, and junctional disruption. Moreover, expression of the epithelia-specific marker E-cadherin was decreased and expression of the myofibroblast-specific marker vimentin was detected in the treated cells. Cell migration and ECM gel invasion were increased. These findings were consistent with events observed during EMT. Hypoxia-induced EMT is accompanied by increased phosphorylation, activation of Akt and the downstream signaling. Hypoxia-induced EMT was blocked by PI3K inhibitor LY294002. The results suggest that the PI3K/Akt-dependent signaling pathways serve to regulate hypoxia-induced EMT of hepatocellular carcinoma cells.

Acquisition of resistance to tamoxifen is a critical therapeutic problem in breast cancer patients. epithelial-mesenchymal transition (EMT), where cells undergo a developmental switch from a polarized epithelial phenotype to a highly motile mesenchymal phenotype, is associated with invasion and motility of cancer cells. Here, we found that tamoxifen-resistant (TAMR)-MCF-7 cells had undergone EMT, as evidenced by mesenchymal-like cell shape, downregulation of basal E-cadherin expression, and overexpression of N-cadherin and vimentin, as well as increased Snail transcriptional activity and protein expression. Given the roles of glycogen synthase kinase (GSK)-3beta and nuclear factor (NF)-kappaB in Snail-mediated E-cadherin deregulation during EMT, we examined the role of these signaling pathways in the EMT of TAMR-MCF-7 cells. Both Ser9-phosphorylated GSK-3beta (inactive form) and NF-kappaB reporter activity were increased in TAMR-MCF-7 cells, as was activation of the phosphatase and tensin homolog depleted on chromosome ten (PTEN)-phosphoinositide 3 (PI3)-kinase-Akt pathway. Pin1, a peptidyl-prolyl isomerase, was overexpressed in TAMR-MCF-7 cells, and Snail transcription and the expression of EMT markers could be decreased by Pin1 siRNA treatment. These results imply that Pin1 overexpression in TAMR-MCF-7 cells is involved in the EMT process via PTEN-PI3-kinase-Akt-GSK-3beta and/or GSK-3beta-NF-kappaB-dependent Snail activation, and suggest the potential involvement of Pin1 in EMT during breast cancer development.

Metastasis of tumor cells is associated with epithelial-to-mesenchymal transition (EMT), which is a process whereby epithelial cells lose their polarity and acquire new features of mesenchyme. EMT has been reported to be induced by transforming growth factor-beta1 (TGF-beta1), but its mechanism remains elusive. In this study, we performed a study to investigate whether PI3K/Akt and MAPK/Erk1/2 signaling pathways involved in EMT in the human lung cancer A549 cells. The results showed that after treated with TGF-beta1 for 48 h, A549 cells displayed more fibroblast-like shape, lost epithelial marker E-cadherin and increased mesenchymal markers Vimentin and Fibronectin. Moreover, TGF-beta1-induced EMT after 48 h was accompanied by increased of cell migration and change of Akt and Erk1/2 phosphorylation. In addition, EMT was reversed by PI3K inhibitor LY294002 and MEK1/2 inhibitor U0126, which suggested that A549 cells under stimulation of TGF-beta1 undergo a switch into mesenchymal cells and PI3K/Akt and MAPK/Erk1/2 signaling pathways serve to regulate TGF-beta1-induced EMT of A549 cells.

Perturbations in the adipocytokine profile, especially higher levels of leptin, are a major cause of breast tumor progression and metastasis; the underlying mechanisms, however, are not well understood. In particular, it remains elusive whether leptin is involved in epithelial-mesenchymal transition (EMT). Here, we provide molecular evidence that leptin induces breast cancer cells to undergo a transition from epithelial to spindle-like mesenchymal morphology. Investigating the downstream mediator(s) that may direct leptin-induced EMT, we found functional interactions between leptin, metastasis-associated protein 1 (MTA1), and Wnt1 signaling components. Leptin increases accumulation and nuclear translocation of beta-catenin leading to increased promoter recruitment. Silencing of beta-catenin or treatment with the small molecule inhibitor, ICG-001, inhibits leptin-induced EMT, invasion, and tumorsphere formation. Mechanistically, leptin stimulates phosphorylation of glycogen synthase kinase 3beta (GSK3beta) via Akt activation resulting in a substantial decrease in the formation of the GSK3beta-LKB1-Axin complex that leads to increased accumulation of beta-catenin. Leptin treatment also increases Wnt1 expression that contributes to GSK3beta phosphorylation. Inhibition of Wnt1 abrogates leptin-stimulated GSK3beta phosphorylation. We also discovered that leptin increases the expression of an important modifier of Wnt1 signaling, MTA1, which is integral to leptin-mediated regulation of the Wnt/beta-catenin pathway as silencing of MTA1 inhibits leptin-induced Wnt1 expression, GSK3beta phosphorylation, and beta-catenin activation. Furthermore, analysis of leptin-treated breast tumors shows increased expression of Wnt1, pGSK3beta, and vimentin along with higher nuclear accumulation of beta-catenin and reduced E-cadherin expression providing in vivo evidence for a previously unrecognized cross-talk between leptin and MTA1/Wnt signaling in epithelial-mesenchymal transition of breast cancer cells.

Both SKP2 (S-phase kinase-associated protein 2) and transforming growth factor-beta1 (TGF-beta1) play important roles in cancer metastasis through different mechanisms: TGF-beta1 via induction of epithelial-mesenchymal transition (EMT) and SKP2 via downregulating p27(kip1). Recent studies indicated that c-Myc and Akt1 were active players in metastasis. In this study we demonstrated a crosstalk between these pathways. Specifically, we found that TGF-beta1 treatment increased SKP2 expression accompanied with increased phosphorylation of Akt1 and c-Myc protein accumulation during EMT. We demonstrated that Akt1 was required for TGF-beta1-mediated SKP2 upregulation and that c-Myc transcription factor specifically bound to the promoter of SKP2 for its enhanced transcription. Analysis of 25 samples of normal human skin, nevi, and melanomas revealed a positive correlation between c-Myc and SKP2 accumulation. Furthermore, accumulation of SKP2 and c-Myc proteins was significantly higher in metastatic melanoma samples as compared with that in primary melanomas, which again was higher than that in normal skin or nevi. In summary, our results integrated TGF-beta1 signals to SKP2 via Akt1 and c-Myc during EMT, and provided, to our knowledge, a previously unreported mechanistic molecular event for TGF-beta1-induced metastasis in human melanoma.

Activation of the serine-threonine protein kinase AKT has emerged as a central feature of epithelial-mesenchymal transition (EMT), which is the initial step for metastasis in many cancer models, including colorectal cancer. The focus of our study was to dissect the role of AKT and its molecular regulation of EMT in colorectal cancer. HCT-116 colorectal cancer cells stably overexpressing AKT (AKT/HCT-116) showed significantly higher cell proliferation compared with vector-transfected cells (pCMV/HCT-116). Elevated expression of important EMT-related transcription factors and genes such as Snail, Slug, beta-catenin, vimentin, and MMP-9 correlated with increased migration and invasion by AKT/HCT-116 cells. Further, in vivo studies confirmed that AKT/HCT-116 xenografts were highly aggressive and angiogenic in nature compared with pCMV/HCT-116 xenografts. Molecular analysis of tumor samples revealed transcriptional regulation of Snail, Slug, beta-catenin, MMP-2, and MMP-9 in AKT/HCT-116 tumors. These results were supported by immunohistochemistry analysis. Low levels of E-cadherin expression with a concomitant increase in and nuclear localization of beta-catenin were evident in AKT/HCT-116 tumors compared with control tumors. Increased microvessel formation coincident with high expression of Factor VIII and increased numbers of reticulocytes confirmed the angiogenic property of AKT/HCT-116 tumors. Our results confirm the potential role of AKT signaling in regulating EMT and angiogenesis in colorectal cancer and suggest that inhibition of AKT can serve as an important therapeutic strategy in modulating EMT in colorectal cancer growth and metastasis.CI - (c) 2013 Wiley Periodicals, Inc.

Chemokine (C-C motif) ligand 18 (CCL18), which is derived from tumour-associated macrophages (TAMs), plays a critical role in promoting breast cancer metastasis via its receptor, PYK2 N-terminal domain interacting receptor 1 (Nir1). However, the molecular mechanism by which Nir1 promotes breast cancer metastasis by binding to CCL18 remains elusive. In this study, Nir1 expression was associated with lymph node and distant metastasis in patients with invasive ductal carcinoma. For the first time, we report that Nir1 binding to CCL18 promotes the phosphorylation of Akt, LIN-11, Isl1 and MEC-3 protein domain kinase (LIMK), and cofilin, which is a critical step in cofilin recycling and actin polymerisation. Interestingly, Nir1 binding to CCL18 can enhance cell mesenchymal properties and induce epithelial-mesenchymal transition (EMT). Mechanistically, Nir1 binding to CCL18 stabilises Snail via the Akt/GSK3beta signalling pathway. In support of these observations, Nir1 binding to CCL18 promoted lung metastasis and LY294002 could inhibit it in vivo. In summary, our in vitro and in vivo results indicate that Nir1 binding to CCL18 plays an important role in breast cancer invasion/metastasis. This study identified both Nir1 and CCL18 as potential anti-invasion targets for therapeutic intervention in breast cancer.CI - Copyright (c) 2013 Elsevier Ltd. All rights reserved.

Head and neck squamous cell carcinoma (HNSCC) is one of the leading causes of cancer deaths worldwide. In recent studies, a crucial link has been discovered between the acquisition of metastatic traits and tumour-initiating abilities in cancer cells during the epithelial-mesenchymal transition (EMT). Herein, we demonstrated that the ectopic expression of TWIST1, the EMT regulator, in HNSCC FaDu cells triggered EMT and resulted in the acquisition of a mesenchymal phenotype. Moreover, FaDu-pFLAG-TWIST1 cancer cell populations that were induced to EMT displayed an increased proportion of cells with the CD44 marker, which is associated with tumour initiation. Interestingly, we found that emodin treatment reduced the tumour-initiating abilities and inhibited cell migration and invasion in FaDu-pFLAG-TWIST1 cells. Emodin directly inhibited TWIST1 expression, upregulated E-cadherin mRNA and protein expression, and downregulated vimentin mRNA and protein expression. Moreover, we found that emodin inhibited TWIST1 binding to the E-cadherin promoter and repressed E-cadherin transcription activity. We also found that emodin inhibited TWIST1-induced EMT by inhibiting the beta-catenin and Akt pathways. More interestingly, emodin significantly inhibited TWIST1-induced invasion in vivo. Therefore, emodin might be applicable to anticancer therapy and could be a potential new therapeutic drug for HNSCC.CI - Copyright (c) 2013 Elsevier Ltd. All rights reserved.

Cisplatin is a first-line chemotherapeutic agent in the treatment of non-small cell lung cancer (NSCLC), but the therapeutic effect is disappointing, partly due to drug resistance. Emerging evidence showed that chemoresistance associates with acquisition of epithelial-mesenchymal transition (EMT) phenotype and cancer stem cell-like properties. However, the underlying mechanism is not entirely clear. In this study, we showed that cisplatin-resistant A549 cells (A549/CDDP) acquire EMT phenotype associated with migratory and invasive capability. A549/CDDP cells also displayed enhanced cancer stem cell-like properties. Increased expression of transcription factor Snail, but not ZEB1, Slug and Twist, was observed in A549/CDDP cells. Knockdown of Snail reversed EMT and significantly attenuated migration, invasion and cancer stem cell-like properties of A549/CDDP cells. Conversely, overexpressed Snail in A549 cells induced EMT and cancer stem cell-like properties. Finally, we demonstrated that activated AKT signal leads to increased beta-catenin expression and subsequently up-regulates Snail in A549/CDDP cells. Taken together, these results revealed that AKT/beta-catenin/Snail signaling pathway is mechanistically associated with cancer stem cell-like properties and EMT features of A549/CDDP cells, and thus, this pathway could be a novel target for the treatment of NSCLC.CI - (c) 2013 Published by Elsevier B.V.

BACKGROUND: epithelial-mesenchymal transition (EMT) is a crucial programme in cancer metastasis. Epidermal growth factor (EGF) is a key inducer of EMT, and Ezrin has an important role in this process. However, how Ezrin is activated and whether it mediates EGF-induced EMT in tongue squamous cell carcinomas (TSCCs) through activating NF-kappaB remains obscure. METHODS: We used two TSCC cell lines as a cell model to study invasion and EMT in vitro, and used nude mice xenografts model to evaluate metastasis of TSCC cells. Finally, we evaluated the level of pEzrin Tyr353, nuclear p65 and EMT markers in TSCC clinical samples. RESULTS: Ezrin Tyr353 was phosphorylated through Akt (but not ERK1/2, ROCK1) pathway, and lead to the activation of NF-kappaB in EGF-treated TSCC cells. Akt and NF-kappaB inhibitors blocked EGF-induced EMT, and suppressed invasion and migration of TSCC cells. In vivo, silencing Ezrin significantly suppressed EGF-enhanced metastasis of TSCC xenografts. Finally, high levels of expression of pEzrin Tyr353, nuclear p65, vimentin and low level of expression of E-cadherin were correlated with cancer metastasis and poor patient prognosis. CONCLUSION: Our data suggest that Akt/Ezrin Tyr353/NF-kappaB pathway regulates EGF-induced EMT and metastasis inTSCC, and Ezrin may serve as a therapeutic target to reverse EMT in tongue cancers and prevent TSCC progression.

BACKGROUND: mTOR, which can form mTOR Complex 1 (mTORC1) or mTOR Complex 2 (mTORC2) depending on its binding partners, is frequently deregulated in the pulmonary neoplastic conditions and interstitial lung diseases of the patients treated with rapalogs. In this study, we investigated the relationship between mTOR signaling and epithelial mesenchymal transition (EMT) by dissecting mTOR pathways. METHODS: Components of mTOR signaling pathway were silenced by shRNA in a panel of non-small cell lung cancer cell lines and protein expression of epithelial and mesenchymal markers were evaluated by immunoblotting and immunocytochemistry. mRNA level of the E-cadherin repressor complexes were evaluated by qRT-PCR. RESULTS: IGF-1 treatment decreased expression of the E-cadherin and rapamycin increased its expression, suggesting hyperactivation of mTOR signaling relates to the loss of E-cadherin. Genetic ablation of rapamycin-insensitive companion of mTOR (Rictor), a component of mTORC2, did not influence E-cadherin expression, whereas genetic ablation of regulatory-associated protein of mTOR (Raptor), a component of mTORC1, led to a decrease in E-cadherin expression at the mRNA level. Increased phosphorylation of AKT at Ser473 and GSK-3beta at Ser9 were observed in the Raptor-silenced NSCLC cells. Of the E-cadherin repressor complexes tested, Snail, Zeb2, and Twist1 mRNAs were elevated in raptor-silenced A549 cells, and Zeb2 and Twist1 mRNAs were elevated in Raptor-silenced H2009 cells. These findings were recapitulated by treatment with the GSK-3beta inhibitor, LiCl. Raptor knockdown A549 cells showed increased expression of N-cadherin and vimentin with mesenchymal phenotypic changes. CONCLUSIONS: In conclusion, selective inhibition of mTORC1 leads to hyperactivation of the AKT/GSK-3beta pathway, inducing E-cadherin repressor complexes and EMT. These findings imply the existence of a feedback inhibition loop of mTORC1 onto mTORC2 that plays a role in the homeostasis of E-cadherin expression and EMT, requiring caution in the clinical use of rapalog and selective mTORC1 inhibitors.

Breast cancer already taken the first place of incidence in Chinese female cancer patients. TRPM8 is found to be over-expressed in breast cancer, but whether it promotes breast cancer aggressiveness remains unknown. In our study, TRPM8 was identified highly expressing in all the tested breast cancer cell lines including MCF-7, T47D, MDA-MB-231, BT549, SKBR3 and ZR-75-30, while it just could be detected in MCF-10A, the normal breast epithelial cell. Then four pairs of clinical samples were analyzed using Western blotting and the result showed that TRPM8 expression is higher in tumor tissues than in adjacent nontumor tissues. Subsequently, we established TRPM8 high-expressing MCF-7 cell line and TRPM8 knockout MDA-MB-231 cell line to explore expression status of cancer-related proteins. The Western blotting and immunofluorescence analysis outcomes demonstrated that TRPM8 might influence cancer cell metastasis by regulating the EMT phenotype via activating AKT/GSK-3beta pathway, and the hypothesis had been supported by cell function tests. All the results demonstrated that TRPM8 significantly up-expressed in breast cancer cells and promoted their metastasis by regulating EMT via activating AKT/GSK-3beta pathway, indicating TRPM8 gets the prospects of to be developed as medication or diagnostic indicator to be applied in clinical work.

Epidermal growth factor-like domain-containing protein 7 (EGFL7) is upregulated in human epithelial tumors and so is a potential biomarker for malignancy. Indeed, previous studies have shown that high EGFL7 expression promotes infiltration and metastasis of gastric carcinoma. The epithelial-mesenchymal transition (EMT) initiates the metastatic cascade and endows cancer cells with invasive and migratory capacity; however, it is not known if EGFL7 promotes metastasis by triggering EMT. We found that EGFL7 was overexpressed in multiple human gastric cancer (GC) cell lines and that overexpression promoted cell invasion and migration as revealed by scratch wound and transwell migration assays. Conversely, shRNA-mediated EGFL7 knockdown reduced invasion and migration. Furthermore, EGFL7-overexpressing cells grew into larger tumors and were more likely to metastasize to the liver compared to underexpressing CG cells following subcutaneous injection in mice. EGFL7 overexpression protected GC cell lines against anoikis, providing a plausible mechanism for this enhanced metastatic capacity. In excised human gastric tumors, expression of EGFL7 was positively correlated with expression levels of the mesenchymal marker vimentin and the EMT-associated transcription repressor Snail, and negatively correlated with expression of the epithelial cell marker E-cadherin. In GC cell lines, EGFL7 knockdown reversed morphological signs of EMT and decreased both vimentin and Snail expression. In addition, EGFL7 overexpression promoted EGF receptor (EGFR) and protein kinase B (AKT) phospho-activation, effects markedly suppressed by the EGFR tyrosine kinase inhibitor AG1478. Moreover, AG1478 also reduced the elevated invasive and migratory capacity of GC cell lines overexpressing EGFL7. Collectively, these results strongly suggest that EGFL7 promotes metastasis by activating EMT through an EGFR-AKT-Snail signaling pathway. Disruption of EGFL7-EGFR-AKT-Snail signaling may a promising therapeutic strategy for gastric cancer.

BACKGROUND: epithelial-mesenchymal transition (EMT) plays a pivotal role in the development of metastatic cancers. Basic fibroblast growth factor (bFGF) is significantly elevated in metastatic prostate cancers, which has been mentioned mainly to induce EMT in normal cells. However, there is no description about bFGF induced EMT and its underlying mechanism in prostate cancer cells. METHODS: Western blotting, immunofluorescence and qRT-PCR assays were used to study protein or mRNA expression profiles of the EMT. Wound healing scratch, migration and invasion assays were used to test the motility of cells undergoing EMT. More methods were used to explore the underlying mechanisms. RESULTS: We demonstrated that bFGF promoted EMT and motility of human prostate cancer PC-3 cells. Both protein and mRNA expression of Snail were rapidly increased after bFGF treatment. Ectopic expression of Snail triggered EMT and enhanced cell motility in PC-3 cells, and knockdown of Snail almost abolished bFGF induced EMT, suggesting the critical role of Snail. Mechanistic study demonstrated that bFGF promoted the stability, nuclear localization and transcription of Snail by inhibiting the activity of glycogen synthase kinase 3 beta (GSK-3beta) through phosphatidylinositide 3 kinases (PI3K)/protein kinase B (AKT) signaling pathway. CONCLUSIONS: It is concluded that bFGF can promote EMT and motility of PC-3 cells, and AKT/GSK-3beta signaling pathway controls the stability, localization and transcription of Snail which is crucial for this bFGF induced EMT. GENERAL SIGNIFICANCE: To our knowledge, this is the first study to demonstrate that bFGF can induce EMT via AKT/GSK-3beta/Snail signaling pathway in prostate cancer cells.CI - Copyright (c) 2014 Elsevier B.V. All rights reserved.

Both circulating tumor cells (CTCs) and epithelial-mesenchymal transition (EMT) play an important role in invasion, migration and chemoresistant in tumor development. This study aimed to detect whether EMT occurred in human gastric CTCs and to explore the mechanism of EMT in human gastric CTCs. We analysed epithelial markers (pan-CK, E-cadherin), mesenchymal markers (N-cadherin, vimentin) EMT related miR200s, and Akt in gastric CTCs. The impact of miR200s on EMT, migration and invasion in CTCs was tested. We found that epithelial markers pan-CK, E-cadherin were decreased, and mesenchymal markers N-cadherin, vimentin were overexpressed in gastric CTCs. expression of EMT related transcriptors, snail1, zeb1, twist1, were reversely correlated with miR200s, and were positively correlated with phospho-Akt. Upregulated of miR200s downregulated twist1 and zeb1 mRNA expression, and resulted in the supression of EMT, and impaired migration and invasion in gastric CTCs. Inhibition of p-Akt led to upregulation of miR200s. In conclusion, gastric CTCs exhibited remarkable EMT process, and p-Akt/miR200s signaling regulates EMT, migration and invasion in gastric CTCs.

miR-21 has been shown to play fundamental role in diverse biological and pathological processes, including fibrotic diseases. In the present study, we investigated whether miR-21 regulated the fibrogenic epithelial-mesenchymal transition (EMT) in human hepatocytes QSG-7701 and explored underlying mechanisms. The results showed that treatment of QSG-7701 cells with pro-fibrogenic factor TGF-beta1 resulted in increased expression of miR-21 and promoted fibrogenic EMT in hepatocytes. Downregulation of miR-21 expression by transfection of anti-miR-21 into QSG-7701 cells inhibited fibrogenic EMT induced by TGF-beta1. Furthermore, overexpression of miR-21 alone also resulted in EMT-like transformation in QSG-7701 cells. TGF-beta1 treatment resulted in decreased PTEN and increased Akt phosphorylation and anti-miR-21 abolished this effect. Overexpression of miR-21 in QSG-7701 cells also downregulated PTEN and upregulated Akt phosphralation. Inhibition of Akt signaling by specific inhibitor Akt inhibitor IV blocked TGF-beta1 and miR-21-induced fibrogenic EMT. In summary, our results identify miR-21 as a key regulator of fibrogenic EMT in hepatocytes via PTEN/Akt pathway. Targeting miR-21 may provide a new therapeutic strategy against hepatic fibrosis.CI - Copyright (c) 2014 Elsevier Masson SAS. All rights reserved.

In our previous study, the epithelial-to-mesenchymal transition (EMT) has been identified to be involved in gastric cancer progression. Notably, nuclear protein C23 and bone morphogenetic protein-2 (BMP2) have been linked into EMT. However, the specific mechanisms underlying BMP2 pathway-mediated EMT are not still unraveled. In this study, we adopted immunohistochemistry and immunoblotting to determine the expression of C23 and BMP2 receptor II (BMPR-II) in 90 gastric cancer samples and cell lines. Subsequently, relevant cell lines were selected to be treated with si-C23 or si-BMPRII and the detection of in vitro assay. Our results revealed that both C23 and BMPRII were aberrantly and constitutively expressed in gastric cancer specimens and cell lines, whose expression was positively associated with metastasis, stage and differentiation, and portended poor survival outcome of gastric cancer patients. In vitro assay validated the increased expression of p-Erk1/2, p-Akt, vimentin, N-cadherin, and MMP2 in BMP2-stimulated MGC803 cells, which was in a dose-dependent manner. By contrast, si-C23 treatment attenuated the BMP2-stimulated expression of p-Erk1/2, p-Akt, vimentin, N-cadherin, and MMP2. Also, the treatment of either si-C23 or si-BMPRII decreased the ability of migration and invasion of MGC803 cells. In conclusion, C23 mediates BMP2-induced EMT progression via the up-regulation of Erk1/2 and Akt signaling pathway in gastric cancer, which indicated both C23 and BMPRII pathway could be recommended as prospective targets or biomarkers to antagonize the progression of gastric cancer.

AIM: To explore whether monocyte chemotactic protein-1 (MCP1) is associated with the epithelial-mesenchymal transition (EMT) and neck metastases in head and neck cancer (HNC). MATERIALS AND METHODS: MCP1 and its related protein were evaluated using western blotting, and a migration assay for HNC cell lines. Thirty-five patients with HNC were recruited for the evaluation of MCP1 expression and pathologically-proven neck metastases from their tissue specimens. RESULTS: MCP1 changed the phenotype of OML-1 cells to a spindle shape, with increased mobility. In OML3 cells, MCP1 knockdown with siRNA blocked EMT. Activation of protein kinase B (AKT) was positively associated with the EMT phenotype, and this transition was abrogated with a phosphoinositide 3 kinase (PI3K) inhibitor. By comparing clinical outcomes, the histological MCP1 score was associated with pathological neck metastases (p=0.027). CONCLUSION: The overexpression of MCP1 in HNC cells may partially induce EMT through the AKT pathway. A high cellular expression of MCP1 was associated with pathological neck metastases.CI - Copyright(c) 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Gefitinib efficiency in non-small-cell lung cancer (NSCLC) therapy is limited due to development of drug resistance. The molecular mechanisms of gefitinib resistance remain still unclear. In this study, we first found that connexin 26 (Cx26) is the predominant Cx isoform expressed in various NSCLC cell lines. Then, two gefitinib-resistant (GR) NSCLC cell lines, HCC827 GR and PC9 GR, from their parental cells were established. In these GR cells, the results showed that gefitinib resistance correlated with changes in cellular EMT phenotypes and upregulation of Cx26. Cx26 was detected to be accumulated in the cytoplasm and failed to establish functional gap-junctional intercellular communication (GJIC) either in GR cells or their parental cells. Ectopic expression of GJIC-deficient chimeric Cx26 was sufficient to induce EMT and gefitinib insensitivity in HCC827 and PC9 cells, while knockdown of Cx26 reversed EMT and gefitinib resistance in their GR cells both in vitro and in vivo. Furthermore, Cx26 overexpression could activate PI3K/Akt signaling in these cells. Cx26-mediated EMT and gefitinib resistance were significantly blocked by inhibition of PI3K/Akt pathway. Specifically, inhibition of the constitutive activation of PI3K/Akt pathway substantially suppressed Cx26 expression, and Cx26 was confirmed to functionally interplay with PI3K/Akt signaling to promote EMT and gefitinib resistance in NSCLC cells. In conclusion, the reciprocal positive regulation between Cx26 and PI3K/Akt signaling contributes to acquired gefitinib resistance in NSCLC cells by promoting EMT via a GJIC-independent manner.

Overexpression of Twist, a highly conserved basic helix-loop-helix transcription factor, is associated with epithelial-mesenchymal transition (EMT) and predicts poor prognosis in various kinds of cancers, including breast cancer. In order to further clarify Twist's role in breast cancer, we detected Twist expression in breast cancer tissues by immunohistochemistry. Twist expression was observed in 54% (220/408) of breast cancer patients and was positively associated with tumor size, Ki67, VEGF-C and HER2 expression. Conversely, Twist was negatively associated with estrogen receptor (ER), progesterone receptor (PgR) and E-cadherin expression. Patients with Twist expression had a poorer prognosis for 30-month disease free survival (DFS) (82.9%) than patients with negative Twist (92.3%). Overexpression of Twist led to dramatic changes in cellular morphology, proliferation, migratory/invasive capability, and expression of EMT-related biomarkers in breast cancer cells. Moreover, we show that Twist serves as a driver of tumorigenesis, as well as an inducer of EMT, at least in part, through activation of the Akt and extracellular signal-regulated protein kinase (ERK) pathways which are critical for Twist-mediated EMT. Our results demonstrate that Twist expression is an important prognostic factor in breast cancer patients.

MicroRNAs (miRNAs) play important roles in epithelial-to-mesenchymal transition (EMT). Moreover, hyperglycaemia induces damage to renal tubular epithelial cells, which may lead to EMT in diabetic nephropathy. However, the effects of miRNAs on EMT in diabetic nephropathy are poorly understood. In the present study, we found that the level of microRNA-23b (miR-23b) was significantly decreased in high glucose (HG)-induced human kidney proximal tubular epithelial cells (HK2) and in kidney tissues of db/db mice. Overexpression of miR-23b attenuated HG-induced EMT, whereas knockdown of miR-23b induced normal glucose (NG)-mediated EMT in HK2 cells. Mechanistically, miR-23b suppressed EMT in diabetic nephropathy by targeting high mobility group A2 (HMGA2), thereby repressing PI3K-AKT signalling pathway activation. Additionally, HMGA2 knockdown or inhibition of the PI3K-AKT signalling pathway with LY294002 mimicked the effects of miR-23b overexpression on HG-mediated EMT, whereas HMGA2 overexpression or activation of the PI3K-AKT signalling pathway with BpV prevented the effects of miR-23b on HG-mediated EMT. We also confirmed that overexpression of miR-23b alleviated EMT, decreased the expression levels of EMT-related genes, ameliorated renal morphology, glycogen accumulation, fibrotic responses and improved renal functions in db/db mice. Taken together, we showed for the first time that miR-23b acts as a suppressor of EMT in diabetic nephropathy through repressing PI3K-AKT signalling pathway activation by targeting HMGA2, which maybe a potential therapeutic target for diabetes-induced renal dysfunction.CI - Copyright (c) 2015 Elsevier Ltd. All rights reserved.

Although periostin was confirmed to facilitate the pathogenesis of endometriosis by enhancing the migration, invasion, and adhesion of human endometrial stromal cells (ESCs), its effect on the endometrial epithelial cells (EECs) is still unknown. The current study aimed to determine whether periostin enhanced the epithelial-mesenchymal transition (EMT) of EECs. EECs were isolated from 12 women with endometriosis. The migration and invasion abilities of EECs were evaluated by transwell assays. expressions of proteins were detected by western blot. After treatment with periostin, the migration and invasion abilities of EECs were enhanced. Additionally, E-cadherin and keratin were downregulated while N-cadherin and vimentin were upregulated in EECs. Simultaneously, levels of ILK, p-Akt, slug, and Zeb1 were all upregulated in EECs. After silencing the expression of ILK in EECs, levels of p-Akt, slug, Zeb1, N-cadherin, and vimentin were downregulated while E-cadherin and keratin were upregulated. Although periostin weakened the above effects in EECs after silencing the expression of ILK, it failed to induce the EMT of EECs. Thus, periostin enhanced invasion and migration abilities of EECs and facilitated the EMT of EECs through ILK-Akt signaling pathway. Playing a pivotal role in the pathogenesis of endometriosis, periostin may be a new clinical therapy target for endometriosis.

epithelial-mesenchymal transition (EMT) plays an important role in metastasis of gastric cancer. Our previous study showed that Gastrokine-2 (GKN2) can inhibit the metastasis of SGC-7901 and AGS cells. Herein, we further explored the role of GKN2 in epithelial mesenchymal transition of gastric cancer cells and the underlying mechanisms. We found that overexpression of GKN2 can lower the protein expression level of Snail and markedly elevate E-cadherin protein level in SGC7901 and AGS cells. Further data showed that knockdown of snail can inhibit the migration and invasion of SGC-7901 and AGS cells. It is known that Snail can be phosphorylated by GSK3beta, a downstream protein of PI3K/AKT pathway. We then test protein expression of p-GSK3beta(Ser-9), the downstream protein of PI3K/AKT, which was significantly decreased under the circumstance of GKN2 overexpression. Moreover, LY294002, a PI3K inhibitor, can reverse the protein expression change of E-cadherin and snail induced by siGKN2. Taken together, these findings suggested that GKN2 suppressed epithelial mesenchymal transition of gastric cancer cells by downregulation of snail through PI3K/AKT/GSK3beta signaling pathway.

The zinc finger protein 143 (ZNF143) is a transcription factor, which regulates many cell cycle-associated genes. ZNF143 expressed strongly in multiple solid tumors. However, the influence of ZNF143 on gastric cancer (GC) remains largely unknown. In this study, we investigated the ZNF143 mRNA level in GC tissues and cells by quantitative real-time PCR (qRT-PCR). The protein expression of ZNF143 in GC cells, and the signaling pathway proteins were detected by Western blotting. Transwell assay and wound healing assay were performed to explore the effects of ZNF143 for the migration ability of GC cells in vitro. We also performed the tail vein injection in nude mice with GC cells to explore the impact of ZNF143 on GC metastasis in vivo. ZNF143 was overexpressed in specimens of GC compared with adjacent normal tissues and increased more significantly in GC tissues of patients who had lymph node metastasis. Ectopic overexpression of ZNF143 enhanced GC migration, whereas ZNF143 knockdown suppressed this effect in vitro. In vivo, ZNF143 knockdown reduced distant metastasis of GC cells in nude mice. In addition, overexpression of ZNF143 reduced the expression of epithelial cell marker (E-cadherin) and induced the expression of mesenchymal cell marker (N-cadherin,Vimentin), Snail and Slug. We also found that ZNF143 enhanced GC cell migration by promoting the process of EMT through PI3K/AKT signaling pathway. In general, our findings show that ZNF143 expressed strongly in GC and enhanced migration of GC cells in vitro and in vivo. It is conceivable that ZNF143 could be a therapeutic genetic target for GC treatment.

Metastasis is the major cause of treatment failure in anaplastic thyroid carcinoma (ATC) patients. In the preliminary study, we demonstrated that interleukin (IL)-11 expression is positively correlated with distant metastasis in ATC. However, the mechanisms underlying remain largely unknown. Here, we found that cobalt chloride (a hypoxia mimetic) promoted IL-11 expression via HIF-1alpha activation. Furthermore, the resultant increase in IL-11 expression significantly induced epithelial-mesenchymal transition (EMT) in ATC cells, accompanied by Akt/GSK3beta pathway activation and increased invasive and migratory abilities. Conversely, HIF-1alpha or IL-11 knockdown, or treating cells with a neutralizing antibody against IL-11, a PI3K inhibitor, or Akt inhibitor V, significantly suppressed the induction of EMT and counteracted the enhancements in invasive and migratory abilities. These results indicate that hypoxia increases IL-11 secretion in ATC cells via HIF-1alpha induction and that IL-11 then induces EMT in these cells via the PI3K/Akt/GSK3beta pathway, ultimately improving their invasive and migratory potential. This study elucidates the prometastatic role played by IL-11 in ATC metastasis and indicates it as a potential target for the treatment of cancer metastasis. However, many questions remain to be explored.

Colorectal cancer(CRC) is one of the most commonly diagnosed cancers in human beings and metastasis is the main death reason. Recently, Gli1 has been reported to be a key regulator of various cancer biologies and genes expressions. However, the detailed molecular mechanism of Gli1 in CRC metastasis remains largely unknown. In this study, we aimed to investigate the role of Gli1 in CRC metastasis. We used qRT-PCR, Immunohistochemistry and Western blot to test the expression levels of Gli1, Foxm1 and other target genes in the tissues and cells; Lentivirus stable transfection to change the expression levels of Gli1 and Foxm1; Wound-healing, cell invasion, migration assays and tail vein metastatic assay to test the role of Gli1 in CRC metastasis in vitro and vivo. We demonstrated that Gli1 was significantly overexpressed in colorectal cancer tissues and cells. Foxm1 level had a positive correlation with Gli1. Furthermore, we found that Gli1 promotes colorectal cancer cells metastasis in a Foxm1-dependent manner by activating EMT and PI3K-AKT signaling. Thus, we proved that Gli1 plays important role in CRC metastasis and provided a new visual field on the therapy of CRC metastasis.

Previous studies have found that miR-375 and miR-205 were significantly dysregulated in laryngeal squamous cell carcinoma, which contributed to the invasion and migration of LSCC. However, the mechanisms of miR-375 and miR-205 regulating the invasion and migration of LSCC remain unknown. qRT-PCR was performed in 40 pairs of tissue samples to investigate the expression of miR-375 and miR-205 in LSCC and paracarcinoma tissues. To investigate whether or not miR-375 and miR-205 regulated the invasion and migration of LSCC synergistically via AKT-mediated epithelial-mesenchymal transition, miR-375 mimic and miR-205 inhibitor were transfected into SNU899 cells and miR-375 inhibitor and miR-205 mimic were transfected into SNU899 cells, respectively, with or without AKT inhibitor. Then the expressions of miR-375 and miR-205 were validated by qRT-PCR, cell migration and invasion were determined by wound healing assay and transwell invasive assay, and western blot analysis was performed to detect the expression of related proteins. Our results showed that miR-375 and miR-205 regulated the invasion and migration of LSCC via AKT-mediated EMT synergistically. In conclusion, our findings provided not only new information about the molecular mechanism of miRNAs regulating invasion and migration of LSCC, but also a theoretical principle for potential targeting therapy of laryngeal squamous carcinoma.

The aim of the present study was to investigate the role of chemokine (C-X-C motif) ligand 8 (CXCL8) in the proliferation, invasiveness and metastasis of colon cancer and its role in the induction of epithelial-mesenchymal transition (EMT) via activation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/nuclear factor-kappaB (NF-kappaB) pathway. The plasmid vector containing CXCL8 cDNA was transfected into LoVo cells using Lipofectamine 2000 reagent. Real-time PCR and western blot analyses were performed to determine expression of CXCL8. MTT growth inhibition, scratch and Transwell invasion assays were conducted to assess cell proliferation, migration and invasiveness of the CXCL8-transfected LoVo cells. Western blot analyses were conducted to measure the levels of phosphorylation of protein in the PI3K/Akt/NF-kappaB pathway in the CXCL8-transfected LoVo cells. expression levels of CXCL8 mRNA and protein were significantly increased in the CXCL8-transfected LoVo cells compared with levels in the control and empty-vector cells (P<0.05). Overexpression of CXCL8 increased proliferation of the LoVo cells and significant differences in cell viability were observed 48 h after transfection (P<0.05) and remained significant at 72 and 96 h. CXCL8-transfected LoVo cells had a significantly higher migration rate and doubled invasion. The CXCL8-transfected LoVo cells exhibited an EMT-like phenotype, compared with control and empty-vector cells, with decreased expression of E-cadherin accompanied by increased expression of N-cadherin, vimentin and alpha-SMA. Overexpression of CXCL8 activated the PI3K/Akt/NF-kappaB pathway by promoting the phosphorylation of PI3K, Akt and NF-kappaB. Subcutaneous tumors were generated by subcutaneous injection of LoVo parental cells or CXCL8-transfected LoVo cells in BALB/c nude mice. The tumor growth was more rapid in the CXCL8-transfected group than that noted in the parental cell group. In conclusion, overexpression of CXCL8 induced cell proliferation, migration and invasion of colon cancer LoVo cells. CXCL8 may act through induction of EMT via the PI3K/AKT/NF-kappaB signaling axis.

A high incidence of tumor recurrence and metastasis has been reported in breast cancer patients; nevertheless, the underlying molecular mechanisms are largely unknown. epithelial-mesenchymal transition (EMT), which is induced by transforming growth factor-beta (TGF-beta), has been implicated in tumorigenesis and breast cancer metastasis. EMT events are now directly associated with tumor metastasis, and this progress is dependent on the inflammatory microenvironment. Cytosolic phospholipase A2alpha (cPLA2alpha) has been shown to participate in a series of biological processes including inflammation and cancer development. However, the role and molecular mechanism of cPLA2alpha in breast cancer EMT and metastasis remain enigmatic. In this study, we found that cPLA2alpha was commonly overexpressed in most human breast cancer tissues and significantly correlated with a poor prognosis for human breast cancer. Functional studies demonstrated that cPLA2alpha overexpression was significantly associated with elevated migration and invasion in MDA-MB-231 and T47D cells. Conversely, reduced cPLA2alpha expression strongly attenuated metastasis and the EMT program of MDA-MB-231 cells. Further study found that knockdown of cPLA2alpha in MDA-MB-231 cells inhibited TGF-beta-induced EMT through the PI3K/Akt signaling pathway. Animal experiments revealed that cPLA2alpha downregulation in MDA-MB-231 cells markedly restrained tumorigenesis and metastasis in vivo. This study indicates the potential role of cPLA2alpha in breast cancer metastasis and indicates that this molecule is a promising therapeutic target for breast cancer.

ADAMTS18 dysregulation plays an important role in many disease processes including cancer. We previously found ADAMTS18 as frequently methylated tumor suppressor gene (TSG) for multiple carcinomas, however, its biological functions and underlying molecular mechanisms in breast carcinogenesis remain unknown. Here, we found that ADAMTS18 was silenced or downregulated in breast cancer cell lines. ADAMTS18 was reduced in primary breast tumor tissues as compared with their adjacent noncancer tissues. ADAMTS18 promoter methylation was detected in 70.8% of tumor tissues by methylation-specific PCR, but none of the normal tissues. Demethylation treatment restored ADAMTS18 expression in silenced breast cell lines. Ectopic expression of ADAMTS18 in breast tumor cells resulted in inhibition of cell migration and invasion. Nude mouse model further confirmed that ADAMTS18 suppressed breast cancer metastasis in vivo. Further mechanistic studies showed that ADAMTS18 suppressed epithelial-mesenchymal transition (EMT), further inhibited migration and invasion of breast cancer cells. ADAMT18 deregulated AKT and NF-kappaB signaling, through inhibiting phosphorylation levels of AKT and p65. Thus, ADAMTS18 as an antimetastatic tumor suppressor antagonizes AKT and NF-kappaB signaling in breast tumorigenesis. Its methylation could be a potential tumor biomarker for breast cancer.CI - (c) 2017 The Authors. cancer Medicine published by John Wiley & Sons Ltd.

Akt1 is essential for the oncogenic transformation and tumor growth in various cancers. However, the precise role of Akt1 in advanced cancers is conflicting. Using a neuroendocrine TRansgenic Adenocarcinoma of the Mouse Prostate (TRAMP) model, we first show that the genetic ablation or pharmacological inhibition of Akt1 in mice blunts oncogenic transformation and prostate cancer (PCa) growth. Intriguingly, triciribine (TCBN)-mediated Akt inhibition in 25-week old, tumor-bearing TRAMP mice and Akt1 gene silencing in aggressive PCa cells enhanced epithelial to mesenchymal transition (EMT) and promoted metastasis to the lungs. Mechanistically, Akt1 suppression leads to increased expression of EMT markers such as Snail1 and N-cadherin and decreased expression of epithelial marker E-cadherin in TRAMP prostate, and in PC3 and DU145 cells. Next, we identified that Akt1 knockdown in PCa cells results in increased production of TGFbeta1 and its receptor TGFbeta RII, associated with a decreased expression of beta-catenin. Furthermore, treatment of PCa cells with ICG001 that blocks nuclear translocation of beta-catenin promoted EMT and N-cadherin expression. Together, our study demonstrates a novel role of the Akt1-beta-catenin-TGFbeta1 pathway in advanced PCa.CI - Copyright (c) 2017 Elsevier B.V. All rights reserved.

Accumulating evidence demonstrates that aberrant miRNAs contribute to gastric cancer (GC) development and progression. However, the roles of various miRNAs in GC remain to be determined. In the present study, we confirmed that a reduced miR-379 expression was present in GC tissues and cell lines. Our clinical analysis revealed that the downregulated miR-379 expression was significantly correlated with poor prognostic features including lymph node metastasis and advanced TNM stage. Moreover, we confirmed that miR-379 was a novel independent prognostic marker for predicting 5-year survival of GC patients. The ectopic overexpression of miR-379 inhibited cell migration, invasion and EMT progress, while downregulated miR-379 reversed the effect. In addition, miR-379 regulated the focal adhesion kinase (FAK) by directly binding to its 3'-UTR, resulting in suppression of AKT signaling. In clinical samples of GC, miR-379 inversely correlated with FAK, which was upregulated in GC. Alteration of FAK expression or activating AKT signaling at least partially abolished the migration, invasion and EMT progress effects of miR-379 on GC cells. In conclusion, our results indicated that miR-379 functioned as a tumor suppressor gene in regulating the EMT and metastasis of GC via targeting FAK/AKT signaling, and may represent a novel potential therapeutic target and prognostic marker for GC.

PURPOSE: Hyperfibrinogenemia is associated with unfavorable prognosis and advanced tumor behavior in various malignancies, including esophageal squamous cell carcinoma (ESCC). However, its biological function in ESCC is unknown. The present study was designed to further validate the prognostic value of preoperative plasma hyperfibrinogenemia and evaluate the biological role of fibrinogen, as well as the underlying mechanism in ESCC. METHODS: Data from 452 cases with newly diagnosed ESCC followed by curative surgery between 2006 and 2010 were retrospectively evaluated. The Clauss method was utilized to measure the preoperative plasma fibrinogen level. Correlations between the fibrinogen level and clinicopathologic characteristics and survival analysis were performed. The effects of fibrinogen on malignant behaviors, including tumor cell viability, colony formation, migration, and invasion, were also investigated. RESULTS: The optimal cut-off value for plasma fibrinogen level was defined as 4.0 g/L according to recommendations. Thus, the proportion of hyperfibrinogenemia was 24.8% (112/452). Preoperative plasma hyperfibrinogenemia was significantly associated with advanced tumor length, deep tumor invasion, advanced tumor-node-metastasis stage, alcohol consumption, a higher white blood cell count, a higher platelet count, and high globulin levels. Univariate survival analysis revealed that compared to those with normal plasma fibrinogen levels, patients with hyperfibrinogenemia tended to have poorer disease-free survival (DFS) [hazard ratio (HR), 1.692; 95% confidence interval (CI), 1.304-2.196; P < 0.001] and overall survival (OS) (HR 1.864; 95% CI 1.424-2.440; P < 0.001). In the multivariate Cox regression models, these factors remained independent predictors for impaired DFS (HR 1.491; 95% CI 1.138-1.955; P = 0.004) and OS (HR 1.648; 95% CI 1.246-2.180; P < 0.001) after adjusting for other confounding variables. In addition, fibrinogen could significantly promote cell migration and invasion but not proliferation. Moreover, it could also induce epithelial-mesenchymal transition (EMT) and increase the levels of p-PTEN, p-AKT, and p-mTOR in ESCC cell lines. CONCLUSIONS: Preoperative plasma hyperfibrinogenemia might serve as an independent predictor of unfavorable survival in ESCC. Furthermore, fibrinogen may promote cell motility by inducing EMT via the p-AKT/p-mTOR pathway.

N-Myc downstream-regulated gene 2 (NDRG2) has recently revealed as a candidate tumor suppressor gene. To inhibit tumor growth and decrease morbidity of esophageal cancer (EC), this study aims to test the hypothesis that the upregulation of NDRG2 may suppress proliferation, invasion, migration and epithelial-mesenchymal transition (EMT) of EC cells by regulating the AKT/XIAP signaling pathway. Immunohistochemistry was conducted for the identification of NDRG2, protein kinase B (p-AKT), X-linked inhibitor of apoptosis protein (XIAP) in EC tissues. To identify the regulatory mechanism of NDRG2 on the AKT/XIAP signaling pathway and EMT in EC, over-expressed lentiviral vector and shRNA were applied for up-regulating and interfering NDRG2 expression, and a series of determinations on the biological behavior of EC cells were performed to validate this regulation action. The results of immunohistochemistry showed NDRG2 was lowly expressed in EC tissues while p-AKT and XIAP are highly expressed. Over-expression of NDRG2 suppresses the proteins related to AKT/XIAP signaling pathway and EMT. Besides, a series of determinations shows the proliferation, migration and invasion of TE-13 cells were suppressed by over-expressed NDRG2, while the cell cycle progression was blocked and cell apoptosis was promoted. And in vivo experiment also demonstrated NDRG2 could inhibit tumor growth. Our findings demonstrate over-expression of NDRG2 works as tumor suppressive role in EC through its effects on inhibition of cell migration, invasion, and EMT by inhibiting the AKT/XIAP signaling pathway.CI - Copyright (c) 2018 Elsevier Ltd. All rights reserved.

G proteincoupled receptor 56 (GPR56), a member of the orphan GPCR family, has been reported to be an oncogene in various malignancies. However, little is known regarding the detailed molecular mechanism of GPR56 in colorectal cancer (CRC). The present study aimed to detect the expression level and biological function of GPR56 in CRC. We examined the expression of GPR56 in CRC tissues and cell lines by quantitative real time (qRT)PCR, immunohistochemistry, and western blot analysis. The prognostic significance of GPR56 in CRC patients was evaluated by KaplanMeier survival analysis. The influence of GPR56 on tumor cell proliferation (via Cell Counting Kit8, and a tumor formation assay in mice), apoptosis (flow cytometry), cell cycle distribution (flow cytometry) and migration (Transwell assay) was explored. We also investigated the underlying mechanism of GPR56 by western blot analysis. We found GPR56 expression was significantly upregulated in CRC tissues and cell lines compared to corresponding normal controls. Higher GPR56 expression in patients predicted poorer prognosis. Depletion of GPR56 markedly suppressed cell proliferation, migration, and invasion. GPR56 overexpression promoted CRC cell metastasis by expediting epithelialmesenchymal transition by activating PI3K/AKT signaling. In conclusion, GPR56 played an important role in CRC progression and may represent a new therapeutic target to reduce CRC metastasis.

Fetal rat hepatocytes treated with transforming growth factor beta (TGF-beta) die by apoptosis. However, a subpopulation of them survives and undergoes an epithelial mesenchymal transition (EMT). This transition also occurs upon incubation with fetal bovine serum. We have isolated the subpopulations that undergo EMT (TGF-beta-treated-fetal hepatocytes: TbetaT-FH; serum-treated-fetal hepatocytes: ST-FH) and show that they present high levels of vimentin and Snail expression and lack cytokeratin 18 and E-cadherin. Both TbetaT-FH and ST-FH cells require mitogens to grow and maintain the response to TGF-beta in terms of growth inhibition. However, they lack differentiation markers such as the liver-enriched transcription factors hepatocyte nuclear factor 4 (HNF-4) or HNF-1alpha and express the progenitor marker OV-6. Interestingly, the EMT process confers them resistance to the apoptotic effect of TGF-beta, with cells showing higher levels of active AKT and Bcl-x(L) than fetal hepatocytes. In summary, these cells are refractory to the apoptotic effects of TGF-beta, showing characteristics of liver progenitors and of some hepatocellular carcinoma cells.

epithelial-mesenchymal transition (EMT) has recently been studied to elucidate mechanisms of the liver metastatic process. We investigated EMT in the process of liver metastasis and the effects of chemotherapy on EMT cells as therapeutic strategy for colorectal liver metastasis. We used the CT26 murine colorectal carcinoma cell line to create an in vivo mouse liver metastasis model. Liver tumors were stained immuno-histochemically. expression of proteins associated with TGF-beta/Smad and hepatocyte growth factor (HGF)/c-Met pathways were investigated by western blotting. Cells with c-Met mRNA knockdown by siRNA techniques showed clearly reduced liver metastases compared with regular cells at 21 days. TGF-beta and HGF induced EMT expression, but signal transduction was quite different. TGF-beta induced ERK, but not Akt phosphory-lation. HGF mediated both ERK and Akt phosphorylation. Akt inhibitor blocked Akt phosphorylation but did not affect TGF-beta-induced activation of ERK, Snail and Slug. U-0126 did not reduce Snail activity by TGF-beta at a concentration to block ERK phosphorylation. However, Akt inhibitor and U-0126 completely inhibited HGF-induced Slug activation. 5-FU mediated cell death in the EMT process induced by TGF-beta more effectively than HGF. ERK/Akt signaling, but not the Smad pathway, may be one of the main processes in HGF-induced EMT, despite the Smad pathway, but not ERK/Akt, being critical for TGF-beta-induced EMT. The MAPK/Akt pathway is indispensable in HGF/c-Met signaling. The ERK/Akt pathway particularly may be critical in the HGF-induced EMT process. However, long-term use of chemotherapeutic agents may induce drug resistance and distant metastases through EMT-related signaling pathway activation.