Project description:Epithelial ovarian cancer (EOC) is clinically heterogeneous, comprising different histological and biological subtypes. Multiple studies have implicated epithelial-mesenchymal transition (EMT), a biological process by which polarized epithelial cells convert into a mesenchymal phenotype, to contribute significantly to this molecular heterogeneity of EOC. From gene expression analyses of a collection of EMT-characterized EOC cell lines, we found that the expression of the transcription factor Grainyhead-like 2 (GRHL2) correlates with E-cadherin expression and the epithelial phenotype. EOC tumors with lower levels of GRHL2 are associated with the Mes (mesenchymal) molecular subtype and show poorer overall survival in patients. Here, we demonstrate that shRNA-mediated knockdown of GRHL2 in EOC cells with an epithelial phenotype resulted in EMT changes, with increased cell migration, invasion and motility. By ChIP-sequencing and gene expression microarray, we identified a variety of target genes regulated by GRHL2, including protein-coding and non-coding genes. Our data suggest that GRHL2 maintains the epithelial phenotype of EOC cells through the regulatory networks of miR-200b/a, ZEB1 and E-cadherin. These findings support GRHL2 as a crucial player in the molecular heterogeneity of EOC. 7 samples were analyzed (shNon control in duplicates; shGRHL2 #10 in duplicates, shGRHL2 #12 in triplicates)
Project description:Epithelial ovarian cancer (EOC) is clinically heterogeneous, comprising different histological and biological subtypes. Multiple studies have implicated epithelial-mesenchymal transition (EMT), a biological process by which polarized epithelial cells convert into a mesenchymal phenotype, to contribute significantly to this molecular heterogeneity of EOC. From gene expression analyses of a collection of EMT-characterized EOC cell lines, we found that the expression of the transcription factor Grainyhead-like 2 (GRHL2) correlates with E-cadherin expression and the epithelial phenotype. EOC tumors with lower levels of GRHL2 are associated with the Mes (mesenchymal) molecular subtype and show poorer overall survival in patients. Here, we demonstrate that shRNA-mediated knockdown of GRHL2 in EOC cells with an epithelial phenotype resulted in EMT changes, with increased cell migration, invasion and motility. By ChIP-sequencing and gene expression microarray, we identified a variety of target genes regulated by GRHL2, including protein-coding and non-coding genes. Our data suggest that GRHL2 maintains the epithelial phenotype of EOC cells through the regulatory networks of miR-200b/a, ZEB1 and E-cadherin. These findings support GRHL2 as a crucial player in the molecular heterogeneity of EOC.
Project description:Epithelial ovarian cancer (EOC) is clinically heterogeneous, comprising different histological and biological subtypes. Multiple studies have implicated epithelial-mesenchymal transition (EMT), a biological process by which polarized epithelial cells convert into a mesenchymal phenotype, to contribute significantly to this molecular heterogeneity of EOC. From gene expression analyses of a collection of EMT-characterized EOC cell lines, we found that the expression of the transcription factor Grainyhead-like 2 (GRHL2) correlates with E-cadherin expression and the epithelial phenotype. EOC tumors with lower levels of GRHL2 are associated with the Mes (mesenchymal) molecular subtype and show poorer overall survival in patients. Here, we demonstrate that shRNA-mediated knockdown of GRHL2 in EOC cells with an epithelial phenotype resulted in EMT changes, with increased cell migration, invasion and motility. By ChIP-sequencing and gene expression microarray, we identified a variety of target genes regulated by GRHL2, including protein-coding and non-coding genes. Our data suggest that GRHL2 maintains the epithelial phenotype of EOC cells through the regulatory networks of miR-200b/a, ZEB1 and E-cadherin. These findings support GRHL2 as a crucial player in the molecular heterogeneity of EOC.
Project description:Epithelial-mesenchymal transition (EMT), a biological process by which polarized epithelial cells convert into a mesenchymal phenotype, has been implicated to contribute to the molecular heterogeneity of epithelial ovarian cancer (EOC). Here we report that a transcription factor--Grainyhead-like 2 (GRHL2) maintains the epithelial phenotype. EOC tumours with lower GRHL2 levels are associated with the Mes/Mesenchymal molecular subtype and a poorer overall survival. shRNA-mediated knockdown of GRHL2 in EOC cells with an epithelial phenotype results in EMT changes, with increased cell migration, invasion and motility. By ChIP-sequencing and gene expression microarray, microRNA-200b/a is identified as the direct transcriptional target of GRHL2 and regulates the epithelial status of EOC through ZEB1 and E-cadherin. Our study demonstrates that loss of GRHL2 increases the levels of histone mark H3K27me3 on promoters and GRHL2-binding sites at miR-200b/a and E-cadherin genes. These findings support GRHL2 as a pivotal gatekeeper of EMT in EOC via miR-200-ZEB1.
Project description:The epithelial-mesenchymal transition (EMT) and mesenchymal-epithelial transition (MET) contribute to cancer metastasis of pancreatic ductal adenocarcinoma (PDAC). We explored the role of grainyhead-like 2 (GRHL2), a suppressor of EMT, in the progression of PDAC. Expressions of GRHL2 were assessed using surgically resected PDAC tissues by immunohistochemistry analysis, and in vitro using human and mouse PDAC cells. Effects on epithelial plasticity and stemness of GRHL2 were examined in vitro using liver metastatic PDAC cells (CFPAC-1) with GRHL2 knockdown by specific siRNAs. GRHL2 has a significantly positive correlation with E-cadherin and CD133 in 155 resected human primary PDAC tissues. GRHL2 is highly expressed in liver metastatic cells than in primary invasive cells of both human and mouse PDAC, accompanied by a positive correlation with E-cadherin expression. GRHL2 knockdown CFPAC-1 cells demonstrated morphological changes into mesenchymal appearances and reduced proliferation through EMT. Notably, knockdown studies followed by flow cytometry analysis for a subpopulation of CD133+ showed that GRHL2 facilitates CFPAC-1 cells to maintain stem-like characters including self-renewal capacity and anoikis resistance. GRHL2 regulates epithelial plasticity along with stemness in PDAC, both of which are crucial for metastasis, implicating the possibility of GRHL2 as a therapeutic target for PDAC liver metastasis.
Project description:Mutations in the genes encoding isocitrate dehydrogenase 1 and 2 (IDH1/2) occur in a variety of tumor types, resulting in production of the proposed oncometabolite, 2-hydroxyglutarate (2-HG). How mutant IDH and 2-HG alter signaling pathways to promote cancer, however, remains unclear. Additionally, there exist relatively few cell lines with IDH mutations. To examine the effect of endogenous IDH mutations and 2-HG, we created a panel of isogenic epithelial cell lines with either wild-type IDH1/2 or clinically relevant IDH1/2 mutations. Differences were noted in the ability of IDH mutations to cause robust 2-HG accumulation. IDH1/2 mutants that produce high levels of 2-HG cause an epithelial-mesenchymal transition (EMT)-like phenotype, characterized by changes in EMT-related gene expression and cellular morphology. 2-HG is sufficient to recapitulate aspects of this phenotype in the absence of an IDH mutation. In the cells types examined, mutant IDH-induced EMT is dependent on up-regulation of the transcription factor ZEB1 and down-regulation of the miR-200 family of microRNAs. Furthermore, sustained knockdown of IDH1 in IDH1 R132H mutant cells is sufficient to reverse many characteristics of EMT, demonstrating that continued expression of mutant IDH is required to maintain this phenotype. These results suggest mutant IDH proteins can reversibly deregulate discrete signaling pathways that contribute to tumorigenesis.
Project description:Epithelial-mesenchymal transition (EMT) is required for the specification of tissues during embryonic development and is recapitulated during the metastatic progression of tumors. The miR-200 family plays a critical role in enforcing the epithelial state with their expression lost in cells undergoing EMT. EMT can be mediated by activation of the ZEB1 and ZEB2 (ZEB) transcription factors, which repress miR-200 expression via a self-reinforcing double negative feedback loop to promote the mesenchymal state. However, it remains unclear what factors drive and maintain epithelial-specific expression of miR-200 in the absence of EMT-inducing factors. Here, we show that the transcription factor Specificity Protein 1 (Sp1) binds to the miR-200b?200a?429 proximal promoter and activates miR-200 expression in epithelial cells. In mesenchymal cells, Sp1 expression is maintained, but its ability to activate the miR-200 promoter is perturbed by ZEB-mediated repression. Reduction of Sp1 expression caused changes in EMT-associated markers in epithelial cells. Furthermore, we observed co-expression of Sp1 and miR-200 during mouse embryonic development wherein miR-200 expression was only lost in regions with high ZEB expression. Together, these findings indicate that miR-200 family members require Sp1 to drive basal expression and to maintain an epithelial state.
Project description:We recently identified Grainyhead-like 2 (GRHL2), a mammalian homolog of Grainyhead in Drosophila, to be a novel transcription factor that regulates hTERT gene expression and enhances proliferation of normal human epidermal keratinocytes (NHEK). In the current study, we show that GRHL2 impairs keratinocyte differentiation through transcriptional inhibition of the genes clustered at the epidermal differentiation complex (EDC), located at chromosome 1q21. Gene expression profiling and subsequent in vitro assays revealed consistent downregulation of EDC genes, for example, IVL, KRT1, FLG, LCEs, and SPRRs, in NHEK expressing exogenous GRHL2. In vivo binding assay by chromatin immunoprecipitation revealed GRHL2 association at the promoter regions of its target genes, many of which belong to EDC. Exogenous GRHL2 expression also inhibited recruitment of histone demethylase Jmjd3 to the EDC gene promoters and enhanced the level of histone 3 Lys 27 trimethylation enrichment at these promoters. Survey of GRHL2 expression in human skin tissues demonstrated enhanced protein and mRNA levels in chronic skin lesions with impaired keratinocyte differentiation, for example, atopic dermatitis and psoriasis, compared with normal epidermis. These data indicate that GRHL2 impairs epidermal differentiation by inhibiting EDC gene expression through epigenetic mechanisms and support its role in the hyperproliferative skin diseases.
Project description:Notch signalling is important for development and tissue homeostasis and activated in many human cancers. Nevertheless, mutations in Notch pathway components are rare in solid tumours. ZEB1 is an activator of an epithelial-mesenchymal transition (EMT) and has crucial roles in tumour progression towards metastasis. ZEB1 and miR-200 family members repress expression of each other in a reciprocal feedback loop. Since miR-200 members target stem cell factors, ZEB1 indirectly induces stemness maintenance and associated drug resistance. Here, we link ZEB1 and its cancer promoting properties to Notch activation. We show that miR-200 members target Notch pathway components, such as Jagged1 (Jag1) and the mastermind-like coactivators Maml2 and Maml3, thereby mediating enhanced Notch activation by ZEB1. We further detected a coordinated upregulation of Jag1 and ZEB1, associated with reduced miR-200 expression in two aggressive types of human cancer, pancreatic adenocarcinoma and basal type of breast cancer. These findings explain increased Notch signalling in some types of cancers, where mutations in Notch pathway genes are rare. Moreover, they indicate an additional way how ZEB1 exerts its tumour progressing functions.
Project description:Ovarian cancer (OC) is the most lethal gynecological malignancy. Its insidious nature, manifesting with little to no symptoms until the disease progresses to metastasis, along with a wide diversity of histological subtypes and corresponding clinical behavior, poses significant therapeutic challenges. The genetic profiling of this aggressive tumor and its subtypes has led to the identification of various molecular markers of prognosis. Among these, the miR-200 family of miRNAs appears to play an important role. The deregulated expression of the miR-200 family members has been detected in a variety of OC studies. The present review examines the potential usefulness of the miR-200 family members as prognostic indicators in ovarian cancer and their impact across different OC publications, with a particular focus on prognostic features, such as disease stage, tumor histology, survival and response to chemotherapy. We present the potential usefulness of the miR-200 family genes as prognostic indicators in OC and highlight the tendency that miR-200 overexpression corresponds with an advanced cancer stage.