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  • ACTIVATION  (3)
  • proliferation  (2)
  • Breast Neoplasms/*drug therapy/*pathology  (1)
  • 1
    Keywords: EXPRESSION ; GROWTH ; FACTOR RECEPTOR ; ACTIVATION ; TNF-ALPHA ; TUMOR-SUPPRESSOR ; MAMMARY-GLAND DEVELOPMENT ; TRANSDUCTION PATHWAYS ; MOLECULAR PORTRAITS ; OVARIAN-TUMORS
    Abstract: Nuclear Factor kappa B (NF-kappaB) signaling is frequently deregulated in a variety of cancers and is constitutively active in estrogen receptor negative (ER-) breast cancer subtypes. These molecular subtypes of breast cancer are associated with poor overall survival. We focused on mechanisms of NF-kappaB regulation by microRNAs (miRNAs), which regulate eukaryotic gene expression at the post-transcriptional level. In a previous genome-wide miRNA screen, we had identified miR-30c-2-3p as one of the strongest negative regulators of NF-kappaB signaling. Here we have uncovered the underlying molecular mechanisms and its consequences in breast cancer. In vitro results show that miR-30c-2-3p directly targets both TNFRSF1A-associated via death domain (TRADD), an adaptor protein of the TNFR/NF-kappaB signaling pathway, and the cell cycle protein Cyclin E1 (CCNE1). Ectopic expression of miR-30c-2-3p downregulated essential cytokines IL8, IL6, CXCL1, and reduced cell proliferation as well as invasion in MDA-MB-231 breast cancer cells. RNA interference (RNAi) induced silencing of TRADD phenocopied the effects on invasion and cytokine expression caused by miR-30c-2-3p, while inhibition of CCNE1 phenocopied the effects on cell proliferation. We further confirmed the tumor suppressive role of this miRNA using a dataset of 781 breast tumors, where higher expression was associated with better survival in breast cancer patients. In summary we have elucidated the mechanism by which miR-30c-2-3p negatively regulates NF-kappaB signaling and cell cycle progression in breast cancer.
    Type of Publication: Journal article published
    PubMed ID: 25732226
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  • 2
    Keywords: proliferation ; PATHWAY ; GENES ; NF-KAPPA-B ; ACTIVATION ; SUPPRESSION ; METASTASIS ; CANCER-CELLS ; TRANSCRIPTIONAL REGULATION ; MIR-31
    Abstract: MicroRNAs post-transcriptionally regulate gene expression and thereby contribute to the modulation of numerous complex and disease-relevant cellular phenotypes, including cell proliferation, cell motility, apoptosis, and stress response. In breast cancer cell systems, miR-31 has been shown to inhibit cell migration, invasion, and metastasis. Here, we link enhanced expression of miR-31 to the inhibition of the oncogenic NF-kappaB pathway, thus supporting the tumor-suppressive function of this microRNA. We identified protein kinase C epsilon (PKCepsilon encoded by the PRKCE gene) as a novel direct target of miR-31 and show that down-regulation of PKCepsilon results in impaired NF-kappaB signaling, enhanced apoptosis, and increased sensitivity of MCF10A breast epithelial and MDA-MB-231 triple-negative breast cancer cells toward ionizing radiation as well as treatment with chemotherapeutics. Mechanistically, we attribute this sensitization to anti-cancer treatments to the PRKCE-mediated down-regulation of the anti-apoptotic factor BCL2. In clinical breast cancer samples, high BCL2 expression was associated with poor prognosis. Furthermore, we found an inverse correlation between miR-31 and BCL2 expression, highlighting the functional relevance of the indirect down-regulation of BCL2 via direct targeting of PRKCE by miR-31.
    Type of Publication: Journal article published
    PubMed ID: 23364795
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  • 3
    Keywords: ANGIOGENESIS ; EXPRESSION ; GROWTH-FACTOR ; INVASION ; proliferation ; ACTIVATION ; UP-REGULATION ; EMBRYONIC STEM-CELLS ; bone metastasis ; MicroRNAs
    Abstract: MicroRNAs (miRNAs) as modulators of gene expression have been described to display both tumor-promoting and tumor-suppressive functions. Although their role has been studied in different tumor types, little is known about how they regulate nuclear factor kappaB (NF-kappaB) signaling in breast cancer. Here, we performed an unbiased whole genome miRNA (miRome) screen to identify novel modulators of NF-kappaB pathway in breast cancer. The screen identified 13 miRNA families whose members induced consistent effects on NF-kappaB activity. Among those, the miR-520/373 family inhibited NF-kappaB signaling through direct targeting of RELA and thus strongly reduced expression and secretion of the pro-inflammatory cytokines interleukin (IL)-6 and IL-8. With a combination of in vitro and in vivo approaches, we propose a metastasis-suppressive role of miR-520/373 family. miR-520c and miR-373 abrogated both in vitro cell invasion and in vivo intravasation of highly invasive MDA-MB-231 cells. However, knockdown of RELA did not affect their metastatic ability. mRNA profiling of MDA-MB-231 cells on overexpression of miR-520/373 members revealed a strong downregulation of transforming growth factor-beta (TGF-beta) signaling. Mechanistically, the metastasis-suppressive role of miR-520/373 can be attributed to direct suppression of TGFBR2, as the silencing of TGFBR2 phenocopied the effects of miR-520/373 overexpression on suppression of Smad-dependent expression of the metastasis-promoting genes parathyroid hormone-related protein, plasminogen activator inhibitor-1 and angiopoietin-like 4 as well as tumor cell invasion, in vitro and in vivo. A negative correlation between miR-520c and TGFBR2 expression was observed in estrogen receptor negative (ER(-)) breast cancer patients but not in the ER positive (ER(+)) subtype. Remarkably, decreased expression of miR-520c correlated with lymph node metastasis specifically in ER(-) tumors. Taken together, our findings reveal that miR-520/373 family has a tumor-suppressive role in ER(-) breast cancer by acting as a link between the NF-kappaB and TGF-beta pathways and may thus contribute to the interplay of tumor progression, metastasis and inflammation.Oncogene advance online publication, 12 December 2011; doi:10.1038/onc.2011.571.
    Type of Publication: Journal article published
    PubMed ID: 22158050
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  • 4
    Publication Date: 2014-10-23
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Keklikoglou, Ioanna -- De Palma, Michele -- England -- Nature. 2014 Nov 6;515(7525):46-7. doi: 10.1038/nature13931. Epub 2014 Oct 22.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Swiss Institute for Experimental Cancer Research, School of Life Sciences, Ecole Polytechnique Federale de Lausanne (EPFL), 1015 Lausanne, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25337881" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Breast Neoplasms/*drug therapy/*pathology ; Chemokine CCL2/*antagonists & inhibitors/*metabolism ; Female ; *Neoplasm Metastasis ; *Neovascularization, Pathologic
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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