| 1. |
- Aydoğdu, Eylem, et al.
(författare)
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MicroRNA-regulated gene networks during mammary cell differentiation are associated with breast cancer.
- 2012
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Ingår i: Carcinogenesis. - : Oxford University Press (OUP). - 0143-3334 .- 1460-2180. ; 33:8, s. 1502-11
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Tidskriftsartikel (refereegranskat)abstract
- MicroRNAs (miRNAs) play pivotal roles in stem cell biology, differentiation and oncogenesis and are of high interest as potential breast cancer therapeutics. However, their expression and function during normal mammary differentiation and in breast cancer remain to be elucidated. In order to identify which miRNAs are involved in mammary differentiation, we thoroughly investigated miRNA expression during functional differentiation of undifferentiated, stem cell-like, murine mammary cells using two different large-scale approaches followed by qPCR. Significant changes in expression of 21 miRNAs were observed in repeated rounds of mammary cell differentiation. The majority, including the miR-200 family and known tumor suppressor miRNAs, was upregulated during differentiation. Only four miRNAs, including oncomiR miR-17, were downregulated. Pathway analysis indicated complex interactions between regulated miRNA clusters and major pathways involved in differentiation, proliferation and stem cell maintenance. Comparisons with human breast cancer tumors showed the gene profile from the undifferentiated, stem-like stage clustered with that of poor-prognosis breast cancer. A common nominator in these groups was the E2F pathway, which was overrepresented among genes targeted by the differentiation-induced miRNAs. A subset of miRNAs could further discriminate between human non-cancer and breast cancer cell lines, and miR-200a/miR-200b, miR-146b and miR-148a were specifically downregulated in triple-negative breast cancer cells. We show that miR-200a/miR-200b can inhibit epithelial-mesenchymal transition (EMT)-characteristic morphological changes in undifferentiated, non-tumorigenic mammary cells. Our studies propose EphA2 as a novel and important target gene for miR-200a. In conclusion, we present evidentiary data on how miRNAs are involved in mammary cell differentiation and indicate their related roles in breast cancer.
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| 2. |
- Katchy, Anne, et al.
(författare)
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Estradiol-activated estrogen receptor α does not regulate mature microRNAs in T47D breast cancer cells.
- 2012
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Ingår i: Journal of Steroid Biochemistry and Molecular Biology. - : Elsevier BV. - 0960-0760 .- 1879-1220. ; 128:3-5, s. 145-53
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Tidskriftsartikel (refereegranskat)abstract
- Breast cancers are sensitive to hormones such as estrogen, which binds to and activates estrogen receptors (ER) leading to significant changes in gene expression. microRNAs (miRNA) have emerged as a major player in gene regulation, thus identification of miRNAs associated with normal or disrupted estrogen signaling is critical to enhancing our understanding of the diagnosis and prognosis of breast cancer. We have previously shown that 17β-estradiol (E2) induced activation of ERα in T47D cells results in significant changes in the expression of protein-coding genes involved in cell cycle, proliferation, and apoptosis. To identify miRNAs regulated by E2-activated ERα, we analysed their expression in T47D cells following E2-activation using both dual-color microarrays and TaqMan Low Density Arrays, and validations were carried out by real-time PCR. Although estrogen treatment results in altered expression of up to 900 protein-coding transcripts, no significant changes in mature miRNA expression levels could be confirmed. Whereas previous studies aiming to elucidate the role of miRNA in ER-positive breast cancers cell lines have yielded conflicting results, the work presented here represents a thorough investigation of and significant step forward in our understanding of ERα mediated miRNA regulation.
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| 3. |
- Tsouko, Efrosini, et al.
(författare)
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miR-200a inhibits migration of triple-negative breast cancer cells through direct repression of the EPHA2 oncogene
- 2015
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Ingår i: Carcinogenesis. - : Oxford University Press. - 0143-3334 .- 1460-2180. ; 36:9, s. 1051-1060
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Tidskriftsartikel (refereegranskat)abstract
- Triple-negative breast cancer (TNBC) is characterized by aggressiveness and affects 10-20% of breast cancer patients. Since TNBC lacks expression of ER alpha, PR and HER2, existing targeted treatments are not effective and the survival is poor. In this study, we demonstrate that the tumor suppressor microRNA miR-200a directly regulates the oncogene EPH receptor A2 (EPHA2) and modulates TNBC migration. We show that EPHA2 expression is correlated with poor survival specifically in basal-like breast cancer and that its expression is repressed by miR-200a through direct interaction with the 3'UTR of EPHA2. This regulation subsequently affects the downstream activation of AMP-activated protein kinase (AMPK) and results in decreased cell migration of TNBC. We establish that miR-200a directs cell migration in a dual manner; in addition to regulating the well-characterized E-cadherin pathway it also regulates a EPHA2 pathway. The miR-200a-EPHA2 axis is a novel mechanism highlighting the possibility of utilizing miR-200a delivery to target TNBC metastases.
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| 4. |
- Wang, Jun, et al.
(författare)
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A miR-206 regulated gene landscape enhances mammary epithelial differentiation.
- 2019
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Ingår i: Journal of Cellular Physiology. - : Wiley. - 0021-9541 .- 1097-4652. ; 234:12, s. 22220-22233
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Tidskriftsartikel (refereegranskat)abstract
- miR-206 is known to suppress breast cancer. However, while it is expressed in mammary stem cells, its function in such nontumor cells is not well understood. Here, we explore the role of miR-206 in undifferentiated, stem-like mammary cells using the murine mammary differentiation model HC11, genome-wide gene expression analysis, and functional assays. We describe the miR-206-regulated gene landscape and propose a network whereby miR-206 suppresses tumor development. We functionally demonstrate that miR-206 in nontumor stem-like cells induces a G1-S cell cycle arrest, and reduces colony formation and epithelial-to-mesenchymal transition markers. Finally, we show that addition of miR-206 accelerates the mammary differentiation process along with related accumulation of lipids. We conclude that miR-206 impacts a network of signaling pathways, and acts as a regulator of proliferation, stemness, and mammary cell differentiation in nontumor stem-like mammary cells. Our study provides a broad insight into the breast cancer suppressive functions of miR-206.
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| 5. |
- Wang, Jun, et al.
(författare)
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miR-206 inhibits cell migration through direct targeting of the actin-binding protein coronin 1C in triple-negative breast cancer
- 2014
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Ingår i: Molecular oncology. - : Wiley. - 1878-0261 .- 1574-7891. ; 8:8, s. 1690-702
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Tidskriftsartikel (refereegranskat)abstract
- Patients with triple-negative breast cancer (TNBC) have an overall poor prognosis, which is primarily due to a high metastatic capacity of these tumors. Novel therapeutic approaches to target the signaling pathways that promote metastasis are desirable, in order to improve the outcome for these patients. A loss of function of a microRNA, miR-206, is related to increased metastasis potential in breast cancers but the mechanism is not known. In this study, we show that miR-206 was decreased in TNBC clinical tumor samples and cell lines whereas one of its predicted targets, actin-binding protein CORO1C, was increased. Expression of miR-206 significantly reduced proliferation and migration while repressing CORO1C mRNA and protein levels. We demonstrate that miR-206 interacts with the 3'-untranslated region (3'-UTR) of CORO1C and regulates this gene post-transcriptionally. This post-transcriptional regulation was dependent on two miR-206-binding sites within the 3'-UTR of CORO1C and was relieved by mutations of corresponding sites. Further, silencing of CORO1C reduced tumor cell migration and affected the actin skeleton and cell morphology, similar to miR-206 expression, but did not reduce proliferation. In accordance with this, overexpression of CORO1C rescued the inhibitory effect of miR-206 on cell migration. Our findings suggest that miR-206 represses tumor cell migration through direct targeting of CORO1C in TNBC cells which modulates the actin filaments. This pathway is a novel mechanism that offers a mechanistic basis through which the metastatic potential of TNBC tumors could be targeted.
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