Project description:Here, we report that the Rho GTPase activators Vav2 and Vav3 utilize a new, miR-200c-dependent mechanism that maintains the epithelial state by limiting the abundance of the Zeb2 transcriptional repressor in breast cancer cells. In parallel, Vav proteins engage an expression program that maintains epithelial cell traits in 3D culture. Depletion of Vav proteins triggers EMT in epithelioid breast cancer cells and, conversely, expression of constitutively active Vav2 restores both miR-200c expression and epithelial traits in mesenchymal breast cancer cells. In silico analyses suggest that the negative Vav-Zeb2 axis is operative in human luminal breast tumors.
Project description:The mouse incisor is a remarkable tooth that grows throughout the animal’s lifetime. This continuous renewal is fueled by epithelial stem cells that give rise to ameloblasts, which generate enamel, and little is known about the function of specific miRNAs in this process. Here we describe the role of a novel Pitx2:miR-200c/141:Noggin regulatory pathway in dental epithelial cell differentiation. miR-200c repressed noggin, an antagonist of Bmp signaling. Pitx2 expression caused an up-regulation of miR-200c and chromatin immunoprecipitation (ChIP) assays revealed endogenous Pitx2 binding to the miR-200c/141 promoter. A positive feedback loop was discovered between miR-200c and Bmp signaling. miR-200c/141 induced expression of E-cadherin and the dental epithelial cell differentiation marker, amelogenin. In addition, miR-203 expression was activated by endogenous Pitx2 and targeted the Bmp antagonist Bmper to further regulate Bmp signaling. miR-200c/141 knockout mice showed defects in enamel formation with decreased E-cadherin and amelogenin expression and increased noggin expression. Our in vivo and in vitro studies reveal a multistep transcriptional program involving the Pitx2:miR-200c/141:Noggin regulatory pathway that is important in epithelial cell differentiation and tooth development.
Project description:The mouse incisor is a remarkable tooth that grows throughout the animalM-bM-^@M-^Ys lifetime. This continuous renewal is fueled by epithelial stem cells that give rise to ameloblasts, which generate enamel, and little is known about the function of specific miRNAs in this process. Here we describe the role of a novel Pitx2:miR-200c/141:Noggin regulatory pathway in dental epithelial cell differentiation. miR-200c repressed noggin, an antagonist of Bmp signaling. Pitx2 expression caused an up-regulation of miR-200c and chromatin immunoprecipitation (ChIP) assays revealed endogenous Pitx2 binding to the miR-200c/141 promoter. A positive feedback loop was discovered between miR-200c and Bmp signaling. miR-200c/141 induced expression of E-cadherin and the dental epithelial cell differentiation marker, amelogenin. In addition, miR-203 expression was activated by endogenous Pitx2 and targeted the Bmp antagonist Bmper to further regulate Bmp signaling. miR-200c/141 knockout mice showed defects in enamel formation with decreased E-cadherin and amelogenin expression and increased noggin expression. Our in vivo and in vitro studies reveal a multistep transcriptional program involving the Pitx2:miR-200c/141:Noggin regulatory pathway that is important in epithelial cell differentiation and tooth development. Lower incisors of 3-5 P0 WT and Pitx2-Cre;Dicer1 cKO mices from same litter were dissected and combined for RNA extraction. Two different litters were analyzed. For mRNA microarray, CodeLink Mouse Whole Genome chips (Applied Microarrays) were used according to manufacturerM-bM-^@M-^Ys instruction (done at Genomics Core of TAMU). miRNA from P0 Lower Incisor ameloblast and cervical loops.
Project description:MiR-200c is a well-studied miRNA that is involved in stemness, the epithelial-mesenchymal transition, chemoresistance, radioresistance, and invasion/metastasis of various cancer cells. To obtain an overview of the lncRNA/mRNA regulated by miR-200c signaling in breast-cancer cell lines, we performed global lncRNA/mRNA-expression profiling on MDA-MB-231-pGIPZ and MDA-MB-231-miR-200c cells.
Project description:Proteomic analysis of differentially expressed proteins in MDA-MB-231 and MCF-10A cell lines when miR-200c and miR-203 were transiently expressed or inhibited, respectively.
Project description:Cell-specific gene expression is achieved by a combination of mechanisms including transcriptional and post-transcriptional regulation. The transcription factor Nkx2-1, essential for lung cell differentiation, mainly acts in transcriptional activation but can directly or indirectly repress gene expression. microRNAs are a class of small non-coding RNA that control one of the major mechanisms of gene repression. To identify miRNAs regulated by Nkx2-1 that may mediate its repressing effects, we knocked-down Nkx2-1 in mouse lung epithelial cell lines and systematically identified targets by genome-wide miR and mRNA expression analyses. Nkx2-1 controls expression of miRs known to contribute to lung cell differentiation in development and disease and others not previously described. Amongst the significantly altered miRs, the mir-106a-363 cluster, miR-1195, miR-378, and miR-346 are directly correlated with the levels of Nkx2-1, whereas miR-200c/b, miR-221, and miR- 222 are inversely correlated. These miRNAs are expressed in embryonic lung at day E11.5, and/or E19.5 determined by in-situ hybridization. Expression of predicted targets of mir-1195, mir-346 and miR-200c and mir-221/222 were evaluated by mRNA expression microarrays in Nkx2-1 knockdown cells identifying those anti-correlated to the corresponding miRNA expression. Genes regulated by mir-1195, Cyp2s1 and Map3k2, by mir-346, Klf6, and miR-200c, Myb, Nfib, and Six1, were validated by qRT-PCR. Inhibition of mir-1195 confirms the inverse correlation of this miRNA with its putative targets Cyp2s1 and Map3k2. This miRNA-mRNA expression analysis identifies potential paths of Nkx2-1 mediated gene repression, and contributes to the understanding of gene regulation in lung epithelial differentiation and development. Nkx2-1 mRNA was knocked down in lung epithelial cells using a lentivirus expressing a shRNA targeting Nkx2-1 (n=3) and compared to empty vector controls (n=3).
Project description:Cell-specific gene expression is achieved by a combination of mechanisms including transcriptional and post-transcriptional regulation. The transcription factor Nkx2-1, essential for lung cell differentiation, mainly acts in transcriptional activation but can directly or indirectly repress gene expression. microRNAs are a class of small non-coding RNA that control one of the major mechanisms of gene repression. To identify miRNAs regulated by Nkx2-1 that may mediate its repressing effects, we knocked-down Nkx2-1 in mouse lung epithelial cell lines and systematically identified targets by genome-wide miR and mRNA expression analyses. Nkx2-1 controls expression of miRs known to contribute to lung cell differentiation in development and disease and others not previously described. Amongst the significantly altered miRs, the mir-106a-363 cluster, miR-1195, miR-378, and miR-346 are directly correlated with the levels of Nkx2-1, whereas miR-200c/b, miR-221, and miR- 222 are inversely correlated. These miRNAs are expressed in embryonic lung at day E11.5, and/or E19.5 determined by in-situ hybridization. Expression of predicted targets of mir-1195, mir-346 and miR-200c and mir-221/222 were evaluated by mRNA expression microarrays in Nkx2-1 knockdown cells identifying those anti-correlated to the corresponding miRNA expression. Genes regulated by mir-1195, Cyp2s1 and Map3k2, by mir-346, Klf6, and miR-200c, Myb, Nfib, and Six1, were validated by qRT-PCR. Inhibition of mir-1195 confirms the inverse correlation of this miRNA with its putative targets Cyp2s1 and Map3k2. This miRNA-mRNA expression analysis identifies potential paths of Nkx2-1 mediated gene repression, and contributes to the understanding of gene regulation in lung epithelial differentiation and development. Nkx2-1 mRNA was knocked down in lung epithelial cells using a lentivirus expressing a shRNA targeting Nkx2-1 (n=3) and compared to empty vector controls (n=3).
Project description:The miR-200 family enforces epithelial identity through suppression of transcriptional and signalling networks that promote Epithelial-Mesenchymal Transition (EMT). Defining features of EMT include cytoskeletal remodelling, altered cell-surface protein expression that reconfigures cell–cell and cell–matrix interactions, and the promotion of primary cilia; specialized membrane protrusions that concentrate receptors and signal transduction proteins to function as antennae for extracellular cues. Such cilia promote stemness and chemoresistance, however the mechanism underlying their upregulation has remained unclear. Here, we identify a previously unrecognised role for miR-200c in controlling ciliogenesis through direct repression of DZIP1, a conserved ciliogenesis assembly factor. miR-200c-mediated repression of DZIP1 is necessary and sufficient to inhibit cilia formation, as DZIP1 knockdown phenocopies miR-200 in reducing ciliation, while DZIP1 re-expression rescues cilia loss. While DZIP1 perturbation alone does not alter canonical EMT markers or the ability of miR-200 to drive MET, transcriptomic profiling shows that a subset of miR-200-responsive gene expression changes are DZIP1-dependent, indicating that miR-200 modulates cilia-associated signalling networks. These findings extend the functional repertoire of miR-200 to include the ciliary sensory structures themselves, as well as co-targeting downstream cytoskeletal and signalling network components. We propose that by suppressing ciliation, sensitivity to pro-EMT stimuli is dampened and epithelial cells are buffered against inappropriate EMT activation.
Project description:mircoRNA-200c (miR-200c) through repression of specific target genes has been associated with cellular transition, tumorigenesis and tissue fibrosis. We explored the expression and functional aspects of miR-200c in genesis of leiomyomas, benign uterine tumors with fibrotic characteristic. Gain-of function of miR-200c in isolated leiomyoma and myometrial smooth muscle cells (LSMC and MSMC) and leiomyosarcoma cell line (SKLM-S1) repressed ZEB1/ZEB2 mRNAs and proteins, with concurrent increase in E-cadherin (CDH1) and reduction in vimentin expression, phenotypic alteration and inhibition of MSMC and LSMC proliferation. We further validated TIMP2, FBLN5 and VEGFA as direct targets of miR-200c through interaction with their respective 3’UTRs, and other genes as determined by microarray analysis.
Project description:mircoRNA-200c (miR-200c) through repression of specific target genes has been associated with cellular transition, tumorigenesis and tissue fibrosis. We explored the expression and functional aspects of miR-200c in genesis of leiomyomas, benign uterine tumors with fibrotic characteristic. Gain-of function of miR-200c in isolated leiomyoma and myometrial smooth muscle cells (LSMC and MSMC) and leiomyosarcoma cell line (SKLM-S1) repressed ZEB1/ZEB2 mRNAs and proteins, with concurrent increase in E-cadherin (CDH1) and reduction in vimentin expression, phenotypic alteration and inhibition of MSMC and LSMC proliferation. We further validated TIMP2, FBLN5 and VEGFA as direct targets of miR-200c through interaction with their respective 3’UTRs, and other genes as determined by microarray analysis. Total RNA isolated from MSMC and LSMC following gain-of function of miR-200c was subjected to gene expression profiling using HumanHT-12 v4 Expression BeadChip (Illumina, Inc. San Diego, CA) consists of 47,000 oligonucleotide probe sets representing 28,688 transcripts.