MicroRNA-200c Represses Migration and Invasion of Breast Cancer Cells by Targeting Actin-Regulatory Proteins FHOD1 and PPM1F

Division of Molecular Genome Analysis, German Cancer Research Center (DKFZ), Heidelberg, Germany.
Molecular and Cellular Biology (Impact Factor: 4.78). 12/2011; 32(3):633-51. DOI: 10.1128/MCB.06212-11
Source: PubMed


MicroRNA-200c (miR-200c) has been shown to suppress epithelial-mesenchymal transition (EMT), which is attributed mainly to targeting of ZEB1/ZEB2, repressors of the cell-cell contact protein E-cadherin. Here we demonstrated that modulation of miR-200c in breast cancer cells regulates cell migration, cell elongation, and transforming growth factor β (TGF-β)-induced stress fiber formation by impacting the reorganization of cytoskeleton that is independent of the ZEB/E-cadherin axis. We identified FHOD1 and PPM1F, direct regulators of the actin cytoskeleton, as novel targets of miR-200c. Remarkably, expression levels of FHOD1 and PPM1F were inversely correlated with the level of miR-200c in breast cancer cell lines, breast cancer patient samples, and 58 cancer cell lines of various origins. Furthermore, individual knockdown/overexpression of these target genes phenocopied the effects of miR-200c overexpression/inhibition on cell elongation, stress fiber formation, migration, and invasion. Mechanistically, targeting of FHOD1 by miR-200c resulted in decreased expression and transcriptional activity of serum response factor (SRF), mediated by interference with the translocation of the SRF coactivator mycocardin-related transcription factor A (MRTF-A). This finally led to downregulation of the expression and phosphorylation of the SRF target myosin light chain 2 (MLC2) gene, required for stress fiber formation and contractility. Thus, miR-200c impacts on metastasis by regulating several EMT-related processes, including a novel mechanism involving the direct targeting of actin-regulatory proteins.

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    • "We identified 117 novel metastasis-related miRNAs in NSCLC based on a well-established metastasis cell model [19]. The finding that miR-200c was downregulated in metastatic SPC-A-1sci cells was intriguing, because decreased miR-200c levels have been reported in several other types of tumor [21,23-25], thus indicating that decreased miR-200c may be a common event in the tumorigenesis. Other reports showed serum miR-200c associated with poor prognosis in patients with lung cancer [32]. "
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    ABSTRACT: Background Growing evidence indicates that miR-200c is involved in carcinogenesis and tumor progression in non-small-cell lung cancer (NSCLC). However, its precise biological role remains largely elusive. Methods The functions of miR-200c and USP25 in migration/invasion and lung metastasis formation were determined by transwell and tail vein injection assays, respectively. The potential regulatory targets of miR-200c were determined by prediction tools, correlation with target protein expression, and luciferase reporter assay. The mRNA expression levels of miR-200c and USP25 were examined in NSCLC cell lines and patient specimens using quantitative reverse transcription-PCR. The protein expression levels of USP25 were examined in NSCLC cell lines and patient specimens using western blot and immunohistochemical staining. Results We demonstrated that over-expression of miR-200c inhibited NSCLC cells migration, invasion, epithelial-mesenchymal transition (EMT) in vitro and lung metastasis formation in vivo. Further studies revealed that USP25 was a downstream target of miR-200c in NSCLC cells as miR-200c bound directly to the 3’-untranslated region of USP25, thus reducing both the messenger RNA and protein levels of USP25. Silencing of the USP25 gene recapitulated the effects of miR-200c over-expression. Clinical analysis indicated that miR-200c was negatively correlated with clinical stage, lymph node metastasis in NSCLC patients. Moreover, USP25 protein and mRNA level expressions were higher in NSCLC patients, compared to healthy control, and correlated with clinical stage and lymphatic node metastasis. Conclusions These findings indicate that miR-200c exerts tumor-suppressive effects for NSCLC through the suppression of USP25 expression and suggests a new therapeutic application of miR-200c in the treatment of NSCLC.
    Full-text · Article · Jul 2014 · Molecular Cancer
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    • "We observed an inverse correlation between miR-200c expression and expression of MUC1, and further evaluated the regulation behind this correlation. MiR-200c regulates a number of proteins associated with epithelial cell differentiation and processes associated with progression of adenocarcinomas [8–11]. Given that MUC1 is known to regulate transcription of a number of processes associated with tumor progression, we hypothesized that transcription of miR-200c was regulated by signal transduction through MUC1. "
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    ABSTRACT: MUC1 is a transmembrane glycoprotein that modulates transcription via its cytoplasmic domain. We evaluated the capacity of MUC1 to regulate the global transcription of microRNAs in pancreatic cancer cells expressing MUC1. Results indicated that MUC1 regulated expression of at least 103 microRNAs. We evaluated further regulation of the microRNA transcript cluster miR-200c/141, which was among the most highly regulated microRNAs. We found that MUC1 directly interacted with ZEB1, a known transcriptional repressor of the miR-200c/141 cluster, at the promoter of miR-200c/141, and further reduced transcript production. These data indicate that signaling through MUC1 influences cancer progression by regulating transcription of microRNAs that are associated with the process of metastasis.
    Full-text · Article · Oct 2013 · PLoS ONE
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    • "ZEB1 inhibits miR-200c expression, while miR-200c in turn inhibits EMT by targeting ZEB1 thereby creating a negative feedback loop [66]. In breast cancer, miR-200c has also been reported to repress EMT independently of ZEB1, by silencing FHOD1, and PPM1F (both play a key role in remodelling the actin cytoskeleton from an epithelial to a mesenchymal phenotype) [67]. This further suggests that enhancing miR-200c expression could be a viable option to limit metastases. "
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    ABSTRACT: Nuclear factor (erythroid-derived 2)-like 2 (NRF2) is a key transcription factor that regulates the expression of over a hundred cytoprotective and antioxidant genes that provide cellular protection from reactive oxygen species. Chemotherapy resistance in several cancers has been linked to dysregulation of the NRF2 signalling pathway, moreover there is growing evidence that NRF2 may contribute to tumorigenesis. MicroRNA (miRNA) are small non-coding RNA sequences that post-transcriptionally regulate mRNA sequences. In cancer pathogenesis, aberrantly expressed miRNAs can act as either tumor suppressor or oncogenic miRNA. Recent evidence has been described that identifies a number of miRNA that can be regulated by NRF2. This review outlines the importance of NRF2 in regulating miRNA, and the functional role this may have in the tumorigenesis of human malignancies and their chemotherapy resistance.
    Full-text · Article · Aug 2013 · Oncotarget
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