The mechanisms that coordinate and balance a complex network of opposing regulators to control Schwann cell (SC) differentiation remain elusive. Here we demonstrate that zinc-finger E-box-binding homeobox 2 (Zeb2, also called Sip1) transcription factor is a critical intrinsic timer that controls the onset of SC differentiation by recruiting histone deacetylases HDAC 1 and 2 (HDAC1/2) and nucleosome remodeling and deacetylase complex (NuRD) co-repressor complexes in mice. Zeb2 deletion arrests SCs at an undifferentiated state during peripheral nerve development and inhibits remyelination after injury. Zeb2 antagonizes inhibitory effectors including Notch and Sox2. Importantly, genome-wide transcriptome analysis reveals a Zeb2 target gene encoding the Notch effector Hey2 as a potent inhibitor for Schwann cell differentiation. Strikingly, a genetic Zeb2 variant associated with Mowat-Wilson syndrome disrupts the interaction with HDAC1/2-NuRD and abolishes Zeb2 activity for SC differentiation. Therefore, Zeb2 controls SC maturation by recruiting HDAC1/2-NuRD complexes and inhibiting a Notch-Hey2 signaling axis, pointing to the critical role of HDAC1/2-NuRD activity in peripheral neuropathies caused by ZEB2 mutations.

Schwann cell development and peripheral nerve myelination require the serial expression of transcriptional activators, such as Sox10, Oct6 (also called Scip or Pou3f1) and Krox20 (also called Egr2). Here we show that transcriptional repression, mediated by the zinc-finger protein Zeb2 (also known as Sip1), is essential for differentiation and myelination. Mice lacking Zeb2 in Schwann cells develop a severe peripheral neuropathy, caused by failure of axonal sorting and virtual absence of myelin membranes. Zeb2-deficient Schwann cells continuously express repressors of lineage progression. Moreover, genes for negative regulators of maturation such as Sox2 and Ednrb emerge as Zeb2 target genes, supporting its function as an 'inhibitor of inhibitors' in myelination control. When Zeb2 is deleted in adult mice, Schwann cells readily dedifferentiate following peripheral nerve injury and become repair cells. However, nerve regeneration and remyelination are both perturbed, demonstrating that Zeb2, although undetectable in adult Schwann cells, has a latent function throughout life.

Early T-cell precursor leukaemia (ETP-ALL) is a high-risk subtype of human leukaemia that is poorly understood at the molecular level. Here we report translocations targeting the zinc finger E-box-binding transcription factor ZEB2 as a recurrent genetic lesion in immature/ETP-ALL. Using a conditional gain-of-function mouse model, we demonstrate that sustained Zeb2 expression initiates T-cell leukaemia. Moreover, Zeb2-driven mouse leukaemia exhibit some features of the human immature/ETP-ALL gene expression signature, as well as an enhanced leukaemia-initiation potential and activated Janus kinase (JAK)/signal transducers and activators of transcription (STAT) signalling through transcriptional activation of IL7R. This study reveals ZEB2 as an oncogene in the biology of immature/ETP-ALL and paves the way towards pre-clinical studies of novel compounds for the treatment of this aggressive subtype of human T-ALL using our Zeb2-driven mouse model.

Mowat-Wilson syndrome (MWS; OMIM #235730) is a genetic condition caused by heterozygous mutations or deletions of the ZEB2 gene, and characterized by typical face, moderate-to-severe mental retardation, epilepsy, Hirschsprung disease, and multiple congenital anomalies, including genital anomalies (particularly hypospadias in males), congenital heart defects, agenesis of the corpus callosum, and eye defects. Since the first delineation by Mowat et al. [Mowat et al. (1998); J Med Genet 35:617-623], approximately 179 patients with ZEB2 mutations, deletions or cytogenetic abnormalities have been reported primarily from Europe, Australia and the United States. Genetic defects include chromosome 2q21-q23 microdeletions (or different chromosome rearrangements) in few patients, and ZEB2 mutations in most. We report on clinical and genetic data from 19 Italian patients, diagnosed within the last 5 years, including six previously published, and compare them with patients already reported. The main purpose of this review is to underline a highly consistent phenotype and to highlight the phenotypic evolution occurring with age, particularly of the facial characteristics. The prevalence of MWS is likely to be underestimated. Knowledge of the phenotypic spectrum of MWS and of its changing phenotype with age can improve the detection rate of this condition.

This review article describes the main features of epithelial-to-mesenchymal transition (EMT) and its possible role in understanding myometrial invasion in endometrial carcinoma (EC), as well as the development of malignant mixed Müllerian tumor (MMMT). Moreover, the article discusses the possible role of somatic (SSC) and cancer stem cells (CSC) in EC. Different transcriptional repressors of E-cadherin have been identified in EMT, including Snail and Slug, ZEB1 and ZEB2, and E47 and Twist. The expression of some of these genes is increased at the myoinvasive front and correlates inversely with E-cadherin inmunoreactivity. Whereas the transient occurrence of the EMT phenomenon is important for myometrial invasion in conventional EC, MMMT shows permanent expression of EMT leading to repression of E-cadherin and increased expression of mesenchymal markers including proteins involved in skeletal muscle development. An SSC population, identified as a side population, assessed by the Hoechst dye exclusion test has been identified in human endometrium. CSCs have been defined in analogy to SSC as cancer cells that have the capacity to self-renew, which means undergoing divisions that allow the generation of more identical CSCs and give rise to the variety of more differentiated cells found in the malignancy. Although published data show that CD133(+) cells retain the characteristics of CSC, there is no conclusive evidence showing that CD133 is the universal marker for EC stem cells. Finally, a possible role for endometrial stem cells in the development of ovarian endometriosis and ovarian endometrioid carcinoma is commented.

MiR-145 could regulate tumor growth, apoptosis, migration, and invasion. In our present study, we investigated its role in epithelial-mesenchymal transition (EMT). Expression of miR-145 was decreased in breast tumor tissues at T3&4 stages in comparison with those at T1&2. Over-expression of miR-145 mimics enhanced protein levels of E-cadherin and dampened those of α-SMA and Fibronectin, indicative of its inhibitory role in EMT occurrence. Mechanistic studies showed that miR-145 mimics inhibited Oct4 expression and miR-145 inhibitor enhanced it. Over-expression of Oct4 reversed miR-145-regulated expression of EMT markers, suggesting that Oct4 mediated the inhibitory effects of miR-145. MiR-145 could inhibite the expression of Snail, ZEB1, and ZEB2, while over-expression of Oct4 rescued the effects. Furthermore, Oct-4 induced over-expression of transcription factor Snail, ZEB1 and ZEB2 was mediated by β-catenin. Expression of Slug and Twist were not altered by miR-145/Oct4. Taken together, our results have revealed a novel role of miR-145 on EMT. It inhibits EMT by blocking the expression of Oct4, and downstream transcriptional factors, Snail, ZEB1 and ZEB2.

BACKGROUND

The Epstein-Barr virus (EBV)-encoded EB nuclear antigen 1 (EBNA1) protein is required for maintenance and transmission of the viral episome in EBV-infected cells. The objective of this study was to investigate the role of EBNA1 protein in nasopharyngeal carcinoma (NPC).

METHODS

Tissue samples from 48 patients with NPC and 12 patients with chronic nasopharyngitis were subjected to immunohistochemical analysis of EBNA1 expression. EBNA1 combinational DNA was used to overexpress EBNA1 protein in NPC cell lines to assess tumor cell epithelial-mesenchymal transition (EMT), colony formation, migration and invasion, and gene expression.

RESULTS

EBNA1 protein was highly expressed in NPC tissue specimens, and its expression was associated with NPC lymph node metastasis. EBNA1 expression affected NPC cell morphology and the expression of EMT markers in vitro. Furthermore, overexpression of EBNA1 inhibited the expression of microRNA 200a (miR-200a) and miR-200b and, in turn, up-regulated expression of their target genes, zinc finger E-box binding homeobox 1 ( ZEB1) and ZEB2, which are well known mediators of EMT. In addition, EBNA1-regulated miR-200a and miR-200b expression was mediated by transforming growth factor-β1.

CONCLUSIONS

The current findings provided novel insight into the vital role of EBNA1 in manipulating a molecular switch of EMT in EBV-positive NPC cells.

Emerging evidence suggests that FoxM1 may have a crucial role in the development and progression of human gastric cancer. Therefore, we sought to determine the role of FoxM1 in gastric cancer epithelial-mesenchymal transition (EMT). The down-regulation of FoxM1 expression by the transfection of cells with FoxM1 siRNA decreased cell migration, invasion, and proliferation. Moreover, the over-expression of FoxM1 promoted cell migration, invasion, and proliferation, which led to the acquisition of an EMT phenotype by up-regulating the protein expression of the mesenchymal cell markers ZEB1, ZEB2, and vimentin and by down-regulating the epithelial cell marker E-cadherin in gastric epithelial cells. More important, the depletion of FoxM1 levels in gastric cancer cells led to significant decreases in the NF-κB p65 subunit, cyclin D1, Hes-1, VEGF, and EpCAM protein levels. Real-time PCR examination showed that the down-regulation of FoxM1 expression significantly inhibited vimentin and N-cadherin expression compared to that in control cells. Most important, cells transfected with FoxM1 siRNA displayed an elongated/irregular fibroblastoid morphology and reduction of the vimentin expression. Our current study strongly suggests that FoxM1 signaling has important roles in tumor cell aggressiveness through the acquisition of the EMT phenotype in gastric cancer cells.

Circulating tumor cells (CTCs), proposed as major players in cancer dissemination, have demonstrated clinical prognostic significance in several cancer types. However, their predictive value remains unclear. Here we evaluated the clinical utility of six CTC markers (tissue specific and epithelial to mesenchymal transition transcripts) both as prognostic and predictive tools in metastatic colorectal cancer (mCRC) patients. CTCs were immunoisolated from blood in 50 mCRC patients at baseline and at 4 and 16 weeks after treatment onset. Expression levels of GAPDH, VIL1, CLU, TIMP1, LOXL3 and ZEB2 were determined by qualitative polymerase chain reaction and normalized to the unspecific cell isolation marker CD45. At baseline, median progression-free survival (PFS) and overall survival (OS) for patients with high CTC markers were 6.3 and 12.7 months, respectively, versus 12.7 and 24.2 for patients with low CTC markers (PFS; p = 0.0003; OS; p = 0.044). Concerning response to therapy, PFS and OS for patients with increased CTC markers along treatment were, respectively, 6.6 and 13.1 months, compared with 12.7 and 24.3 for patients presenting CTC markers reduction (PFS; p = 0.004; OS; p = 0.007). Of note, CTC markers identified therapy-refractory patients not detected by standard image techniques. Patients with increased CTC markers along treatment, but classified as responders by computed tomography, showed significantly shorter survival times (PFS: 7.8 vs. 13.2; OS: 14.4 vs. 24.4; months). In conclusion, we have generated a CTC marker panel for prognosis evaluation and the identification of patients benefiting or not from therapy in mCRC. Our methodology efficiently classified patients earlier than routine computed tomography and from a minimally invasive liquid biopsy.

Most B cell precursor acute lymphoblastic leukemia (BCP ALL) can be classified into known major genetic subtypes, while a substantial proportion of BCP ALL remains poorly characterized in relation to its underlying genomic abnormalities. We therefore initiated a large-scale international study to reanalyze and delineate the transcriptome landscape of 1,223 BCP ALL cases using RNA sequencing. Fourteen BCP ALL gene expression subgroups (G1 to G14) were identified. Apart from extending eight previously described subgroups (G1 to G8 associated with MEF2D fusions, TCF3-PBX1 fusions, ETV6-RUNX1-positive/ETV6-RUNX1-like, DUX4 fusions, ZNF384 fusions, BCR-ABL1/Ph-like, high hyperdiploidy, and KMT2A fusions), we defined six additional gene expression subgroups: G9 was associated with both PAX5 and CRLF2 fusions; G10 and G11 with mutations in PAX5 (p.P80R) and IKZF1 (p.N159Y), respectively; G12 with IGH-CEBPE fusion and mutations in ZEB2 (p.H1038R); and G13 and G14 with TCF3/4-HLF and NUTM1 fusions, respectively. In pediatric BCP ALL, subgroups G2 to G5 and G7 (51 to 65/67 chromosomes) were associated with low-risk, G7 (with ≤50 chromosomes) and G9 were intermediate-risk, whereas G1, G6, and G8 were defined as high-risk subgroups. In adult BCP ALL, G1, G2, G6, and G8 were associated with high risk, while G4, G5, and G7 had relatively favorable outcomes. This large-scale transcriptome sequence analysis of BCP ALL revealed distinct molecular subgroups that reflect discrete pathways of BCP ALL, informing disease classification and prognostic stratification. The combined results strongly advocate that RNA sequencing be introduced into the clinical diagnostic workup of BCP ALL.

Plasmacytoid dendritic cells (DCs [pDCs]) develop from pre-pDCs, whereas two lineages of conventional DCs (cDCs; cDC1s and cDC2s) develop from lineage-committed pre-cDCs. Several transcription factors (TFs) have been implicated in regulating the development of pDCs (E2-2 and Id2) and cDC1s (Irf8, Id2, and Batf3); however, those required for the early commitment of pre-cDCs toward the cDC2 lineage are unknown. Here, we identify the TF zinc finger E box-binding homeobox 2 (Zeb2) to play a crucial role in regulating DC development. Zeb2 was expressed from the pre-pDC and pre-cDC stage onward and highly expressed in mature pDCs and cDC2s. Mice conditionally lacking Zeb2 in CD11c(+) cells had a cell-intrinsic reduction in pDCs and cDC2s, coupled with an increase in cDC1s. Conversely, mice in which CD11c(+) cells overexpressed Zeb2 displayed a reduction in cDC1s. This was accompanied by altered expression of Id2, which was up-regulated in cDC2s and pDCs from conditional knockout mice. Zeb2 chromatin immunoprecipitation analysis revealed Id2 to be a direct target of Zeb2. Thus, we conclude that Zeb2 regulates commitment to both the cDC2 and pDC lineages through repression of Id2.

The Forkhead Box A2 (FOXA2) transcription factor is required for embryonic development and for normal functions of multiple adult tissues, in which the maintained expression of FOXA2 is usually related to preventing the progression of malignant transformation. In this study, we found that FOXA2 prevented the epithelial to mesenchymal transition (EMT) in human breast cancer. We observed a strong correlation between the expression levels of FOXA2 and the epithelial phenotype. Knockdown of FOXA2 promoted the mesenchymal phenotype, whereas stable overexpression of FOXA2 attenuated EMT in breast cancer cells. FOXA2 was found to endogenously bind to and stimulate the promoter of E-cadherin that is crucial for epithelial phenotype of the tumor cells. Meanwhile, FOXA2 prevented EMT of breast cancer cells by repressing the expression of EMT-related transcription factor ZEB2 through recruiting a transcriptional corepressor TLE3 to the ZEB2 promoter. The stable overexpression of FOXA2 abolished metastasis of breast cancer cells in vivo. This study confirmed that FOXA2 inhibited EMT in breast cancer cells by regulating the transcription of EMT-related genes such as E-cadherin and ZEB2.

The microRNA (miRNA) landscape changes during the progression of cancer. We defined a metastasis-associated miRNA landscape using a systematic approach. We profiled and validated miRNA and mRNA expression in a unique series of human colorectal metastasis tissues together with their matched primary tumors and corresponding normal tissues. We identified an exclusive miRNA signature that is differentially expressed in metastases. Three of these miRNAs were identified as key drivers of an EMT-regulating network acting though a number of novel targets. These targets include SIAH1, SETD2, ZEB2, and especially FOXN3, which we demonstrated for the first time as a direct transcriptional suppressor of N-cadherin. The modulation of N-cadherin expression had significant impact on migration, invasion, and metastasis in two different in vivo models. The significant deregulation of the miRNAs defining the network was confirmed in an independent patient set as well as in a database of diverse malignancies derived from more than 6,000 patients. Our data define a novel metastasis-orchestrating network based on systematic hypothesis generation from metastasis tissues.

Triple-negative breast cancer (TNBC) is a highly aggressive breast cancer subtype that lacks effective targeted therapies. The epithelial-to-mesenchymal transition (EMT) is a key contributor in the metastatic process. We previously showed the pan-deacetylase inhibitor LBH589 induces CDH1 expression in TNBC cells, suggesting regulation of EMT. The purpose of this study was to examine the effects of LBH589 on the metastatic qualities of TNBC cells and the role of EMT in this process. A panel of breast cancer cell lines (MCF-7, MDA-MB-231, and BT-549), drugged with LBH589, was examined for changes in cell morphology, migration, and invasion in vitro. The effect on in vivo metastasis was examined using immunofluorescent staining of lung sections. EMT gene expression profiling was used to determine LBH589-induced changes in TNBC cells. ZEB overexpression studies were conducted to validate requirement of ZEB in LBH589-mediated proliferation and tumorigenesis. Our results indicate a reversal of EMT by LBH589 as demonstrated by altered morphology and altered gene expression in TNBC. LBH589 was shown to be a more potent inhibitor of EMT than other HDAC inhibitors, SAHA and TMP269. Additionally, we found that LBH589 inhibits metastasis of MDA-MB-231 cells in vivo. These effects of LBH589 were mediated in part by inhibition of ZEB, as overexpression of ZEB1 or ZEB2 mitigated the effects of LBH589 on MDA-MB-231 EMT-associated gene expression, migration, invasion, CDH1 expression, and tumorigenesis. These data indicate therapeutic potential of LBH589 in targeting EMT and metastasis of TNBC.

Abnormal DNA methylation at the C-5 position of cytosine (5mC) of CpG dinucleotides is a well-known epigenetic feature of cancer. Levels of E-cadherin, which is regularly expressed in epithelial tissues, are frequently reduced in epithelial tumors due to transcriptional repression, sometimes accompanied by hypermethylation of the promoter region. δEF1 family proteins (δEF1/ZEB1 and SIP1/ZEB2), key regulators of the epithelial-mesenchymal transition (EMT), suppress E-cadherin expression at the transcriptional level. We recently showed that levels of mRNAs encoding δEF1 proteins are regulated reciprocally with E-cadherin level in breast cancer cells. Here, we examined the mechanism underlying downregulation of E-cadherin expression in three basal-type breast cancer cells in which the E-cadherin promoter region is hypermethylated (Hs578T) or moderately methylated (BT549 and MDA-MB-231). Regardless of methylation status, treatment with 5-aza-2'-deoxycytidine (5-aza), which inhibits DNA methyltransferases, had no effect on E-cadherin expression. Knockdown of δEF1 and SIP1 resulted in recovery of E-cadherin expression in cells lacking hypermethylation, whereas combined treatment with 5-aza synergistically restored E-cadherin expression, especially when the E-cadherin promoter was hypermethylated. Moreover, δEF1 interacted with DNA methyltransferase 1 (DNMT1) through the Smad-binding domain. Sustained knockdown of δEF1 family proteins reduced the number of 5mC sites in the E-cadherin promoter region, suggesting that these proteins maintain 5mC through interaction with DNMT1 in breast cancer cells. Thus, δEF1 family proteins appear to repress expression of E-cadherin during cancer progression, both directly at the transcriptional level and indirectly at the epigenetic level.

Inactivation of p53 contributes significantly to the dismal prognosis of breast tumors, most notably triple-negative breast cancers (TNBCs). How the relief from p53 tumor suppressive functions results in tumor cell aggressive behavior is only partially elucidated. In an attempt to shed light on the implication of microRNAs in this context, we discovered a new signaling axis involving p53, miR-30a and ZEB2. By an in silico approach we identified miR-30a as a putative p53 target and observed that in breast tumors reduced miR-30a expression correlated with p53 inactivation, lymph node positivity and poor prognosis. We demonstrate that p53 binds the MIR30A promoter and induces the transcription of both miRNA strands 5p and 3p. Both miR-30a-5p and -3p showed the capacity of targeting ZEB2, a transcription factor involved in epithelial-mesenchymal transition (EMT), tumor cell migration and drug resistance. Intriguingly, we found that p53 does restrain ZEB2 expression via miR-30a. Finally, we provide evidence that the new p53/miR-30a/ZEB2 axis controls tumor cell invasion and distal spreading and impinges upon miR-200c expression. Overall, this study highlights the existence of a novel axis linking p53 to EMT via miR-30a, and adds support to the notion that miRNAs represent key elements of the complex network whereby p53 inactivation affects TNBC clinical behavior.

Ovarian carcinoma is the most lethal gynecologic malignancy; the majority of patients succumb to the disease within 5 years of diagnosis. The poor survival rate is attributed to diagnosis at advanced stage, when the tumor has metastasized. The epithelial-to-mesenchymal transition (EMT) is a necessary step toward metastatic tumor progression. Through integrated computational analysis, we recently identified a master microRNA (miRNA) network that includes miR-101 and regulates EMT in ovarian carcinoma. In the present study, we characterized the functions of miR-101. Using reporter gene assays, we demonstrated that miR-101 suppressed the expression of the E-cadherin repressors ZEB1 and ZEB2 by directly targeting the 3'-untranslated region (3'UTR) of both ZEB1 and ZEB2. Introduction of miR-101 significantly inhibited EMT and cell migration and invasion. Introducing cDNAs of ZEB1 and ZEB2 without 3'UTR abrogated miR-101-induced EMT alteration, respectively. Our findings showed that miR-101 represents a redundant mechanism for the miR-200 family that regulates EMT through two major E-cadherin transcriptional repressors.

Epithelial-to-Mesenchymal Transition (EMT) is a key process contributing to the aggressiveness of cancer cells. EMT is triggered by activation of different transcription factors collectively known as EMT-TFs. Different cellular cues and cell signalling networks activate EMT at transcriptional and posttranscriptional level in different biological and pathological situations. Among them, overexpression of LOXL2 (lysyl oxidase-like 2) induces EMT independent of its catalytic activity. Remarkably, perinuclear/cytoplasmic accumulation of LOXL2 is a poor prognosis marker of squamous cell carcinomas and is associated to basal breast cancer metastasis by mechanisms no yet fully understood. Here, we report that overexpression of LOXL2 promotes its accumulation in the Endoplasmic Reticulum where it interacts with HSPA5 leading to activation of the IRE1-XBP1 signalling pathway of the ER-stress response. LOXL2-dependent IRE1-XBP1 activation induces the expression of several EMT-TFs: SNAI1, SNAI2, ZEB2 and TCF3 that are direct transcriptional targets of XBP1. Remarkably, inhibition of IRE1 blocks LOXL2-dependent upregulation of EMT-TFs thus hindering EMT induction.

Hyperactivation of the Wingless-type (Wnt)/β-catenin pathway promotes tumor initiation, tumor growth and metastasis in various tissues. Although there is evidence for the involvement of Wnt/β-catenin pathway activation in salivary gland tumors, the precise mechanisms are unknown. Here we report for the first time that downregulation of the Wnt inhibitory factor 1 (WIF1) is a widespread event in salivary gland carcinoma ex-pleomorphic adenoma (CaExPA). We also show that WIF1 downregulation occurs in the CaExPA precursor lesion pleomorphic adenoma (PA) and indicates a higher risk of progression from benign to malignant tumor. Our results demonstrate that diverse mechanisms including WIF1 promoter hypermethylation and loss of heterozygosity contribute to WIF1 downregulation in human salivary gland tumors. In accordance with a crucial role in suppressing salivary gland tumor progression, WIF1 re-expression in salivary gland tumor cells inhibited cell proliferation, induced more differentiated phenotype and promoted cellular senescence, possibly through upregulation of tumor-suppressor genes, such as p53 and p21. Most importantly, WIF1 significantly diminished the number of salivary gland cancer stem cells and the anchorage-independent cell growth. Consistent with this observation, WIF1 caused a reduction in the expression of pluripotency and stemness markers (OCT4 and c-MYC), as well as adult stem cell self-renewal and multi-lineage differentiation markers, such as WNT3A, TCF4, c-KIT and MYB. Furthermore, WIF1 significantly increased the expression of microRNAs pri-let-7a and pri-miR-200c, negative regulators of stemness and cancer progression. In addition, we show that WIF1 functions as a positive regulator of miR-200c, leading to downregulation of BMI1, ZEB1 and ZEB2, with a consequent increase in downstream targets such as E-cadherin. Our study emphasizes the prognostic and therapeutic potential of WIF1 in human salivary gland CaExPA. Moreover, our findings demonstrate a novel mechanism by which WIF1 regulates cancer stemness and senescence, which might have major implications in the field of cancer biology.

Cigarette smoking is a major risk factor in the development of non-small cell lung cancer (NSCLC), which accounts for 80% of all lung cancers. Nicotine, the major addictive component of tobacco smoke, can induce proliferation, invasion, and epithelial-to-mesenchymal transition (EMT) in NSCLC cell lines and promote metastasis of NSCLC in mice. Here, we demonstrate that the scaffolding protein β-arrestin-1 is necessary for nicotine-mediated induction of mesenchymal genes vimentin and fibronectin as well as EMT regulators ZEB1 and ZEB2. Nicotine induced changes in cell morphology and ablate tight junctions consistent with EMT; β-arrestin-1, but not β-arrestin-2, was required for these changes. β-Arrestin-1 promoted the expression of the mesenchymal genes, as well as ZEB1 and ZEB2, through the mediation of the E2F1 transcription factor; this required Src kinase activity. Stimulation of multiple NSCLC cell lines with nicotine led to enhanced recruitment of β-arrestin-1 and E2F1 on vimentin, fibronectin, and ZEB1 and ZEB2 promoters. Furthermore, there was significantly more β-arrestin-1 and E2F1 associated with these promoters in human NSCLC tumors, and β-arrestin-1 levels correlated with vimentin and fibronectin levels in human NSCLC samples. A549-luciferase cells lacking β-arrestin-1 showed a significantly reduced capacity for tumor growth and metastasis when orthotopically implanted into the lungs of SCID-beige mice. Taken together, these studies reveal a novel role for β-arrestin-1 in the growth and metastasis of NSCLC.

Invasion and migration of glioblastoma multiforme (GBM) is a multistep process and an important phenotype that causes this disease to invade surrounding tissues in the brain. The purpose of this study was to determine the role of miR-590-3p in regulation of epithelial mesenchymal transition (EMT) and metastasis of GBM cells. Expression levels of miR-590-3p in 15 GBM specimens with adjacent tissues and five GBM cell lines were assessed by quantitative RT-PCR. We found that miR-590-3p was down-regulated in detected GBM tissue samples and all of the GBM cell lines. In addition, Ectopic expression of miR-590-3p suppressed and miR-590-3p-in promoted EMT, migration, and invasion in U87MG and A172 cells. Bioinformatics coupled with luciferase and Western blot assays also revealed that miR-590-3p inhibited expression of ZEB1 and ZEB2, which are master regulators of tumor metastasis. Our study first indicates that miR-590-3p functions as a suppressor of GBM EMT and metastasis by targeting ZEB1 and ZEB2, and it may be a therapeutic target for metastatic GBM.

Histone methylation is implicated in various biological and pathological processes including cancer development. In this study, we discovered that ectopic expression of KDM5B, a histone H3 lysine 4 (H3K4) demethylase, promoted epithelial-mesenchymal transition (EMT) of cancer cells. KDM5B increased the expression of transcription factors, ZEB1 and ZEB2, followed by downregulation of E-cadherin and upregulation of mesenchymal marker genes. The expression of the microRNA-200 (miR-200) family, which specifically targets ZEB1 and ZEB2, was reduced in the cells with KDM5B overexpression. We found that KDM5B repressed the expression of the miR-200 family by changing histone H3 methylation status of their regulatory regions. The introduction of miR-200 precursor in the cells inhibited EMT induction by KDM5B, suggesting that miR-200 family was a critical downstream mediator of KDM5B-promoted EMT. Furthermore, knockdown of KDM5B was shown to affect the expression of EMT-related genes, indicating the involvement of endogenous KDM5B. Our study demonstrated a novel role of KDM5B histone lysine demethylase in EMT, which may contribute to malignant progression of cancer.

OBJECTIVE

The cases of bladder cancer (BC) with poor prognosis largely result from the distal metastases of the primary tumor. Since microRNAs (miRNAs) play critical roles during cancer metastases, determination of the involved miRNAs in the regulation of the metastases of BC may provide novel therapeutic targets for BC treatment. Here, we aimed to study the role of miR-138 in regulation of BC cell invasion and metastases.

METHODS

We analyzed the levels of miR-138 and ZEB2, a key factor that regulates cancer cell invasion, in the BC specimens from the patients. We also studied the correlation between miR-138 and ZEB2. We performed bioinformatics analyses on the binding of miR-138 to the 3'-UTR of ZEB2 mRNA, and verified the biological effects of this binding through promoter luciferase reporter assay. The effects of miR-138-modification on BC cell invasion were evaluated in a transwell cell invasion assay and a scratch would healing assay.

RESULTS

We found that the levels of miR-138 were significantly decreased and the levels of ZEB2 were significantly increased in BC specimens, compared to the paired normal bladder tissue. Metastatic BC appeared to contained lower levels of miR-138. Moreover, miR-138 and ZEB2 inversely correlated in BC specimens. Bioinformatics analyses showed that miR-138 targeted the 3'-UTR of ZEB2 mRNA to inhibit its translation. Furthermore, miR-138 overexpression inhibited ZEB2-mediated cell invasion and metastases, while miR-138 depletion increased ZEB2-mediated cell invasion and metastases in BC cells.

CONCLUSIONS

Suppression of miR-138 in BC cells may promote ZEB2-mediated cancer invasion and metastases. Thus, miR-138 appears to be an intriguing therapeutic target to prevent metastases of BC.

Endometriosis is characterized by growth of endometrial tissue at ectopic locations. Down-regulation of microRNA miR-200b is observed in endometriosis and malignant disease, driving tumour cells towards an invasive state by enhancing epithelial-to-mesenchymal transition (EMT). miR-200b up-regulation may inhibit EMT and invasive growth in endometriosis. To study its functional impact on the immortalized endometriotic cell line 12Z, the stromal cell line ST-T1b, and primary endometriotic stroma cells, a transient transfection approach with microRNA precursors was employed. Expression of bioinformatically predicted targets of miR-200b was analysed by qPCR. The cellular phenotype was monitored by Matrigel invasion assays, digital-holographic video microscopy and flow cytometry. qPCR revealed significant down-regulation of ZEB1 (P < 0.05) and ZEB2 (P < 0.01) and an increase in E-cadherin (P < 0.01). miR-200b overexpression decreased invasiveness (P < 0.0001) and cell motility (P < 0.05). In contrast, cell proliferation (P < 0.0001) and the stemness-associated side population phenotype (P < 0.01) were enhanced following miR-200b transfection. These properties were possibly due to up-regulation of the pluripotency-associated transcription factor KLF4 (P < 0.05) and require attention when considering therapeutic strategies. In conclusion, up-regulation of miR-200b reverts EMT, emerging as a potential therapeutic approach to inhibit endometriotic cell motility and invasiveness.