Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • proliferation  (2)
  • Breast Neoplasms/*drug therapy/*pathology  (1)
  • CHRONIC LYMPHOCYTIC-LEUKEMIA  (1)
  • 1
    Keywords: DNA methylation ; FACTOR-KAPPA-B ; CHRONIC LYMPHOCYTIC-LEUKEMIA ; DISEASE PROGRESSION ; CHROMOSOME 13Q14 ; TUMOR-SUPPRESSOR LOCUS ; LONG NONCODING RNAS ; PROMOTER CPG METHYLATION ; PI3K/NF-KAPPA-B PATHWAY ; ANTISENSE TRANSCRIPTS
    Abstract: Non-coding RNAs are much more common than previously thought. However, for the vast majority of non-coding RNAs, the cellular function remains enigmatic. The two long non-coding RNA (lncRNA) genes DLEU1 and DLEU2 map to a critical region at chromosomal band 13q14.3 that is recurrently deleted in solid tumors and hematopoietic malignancies like chronic lymphocytic leukemia (CLL). While no point mutations have been found in the protein coding candidate genes at 13q14.3, they are deregulated in malignant cells, suggesting an epigenetic tumor suppressor mechanism. We therefore characterized the epigenetic makeup of 13q14.3 in CLL cells and found histone modifications by chromatin-immunoprecipitation (ChIP) that are associated with activated transcription and significant DNA-demethylation at the transcriptional start sites of DLEU1 and DLEU2 using 5 different semi-quantitative and quantitative methods (aPRIMES, BioCOBRA, MCIp, MassARRAY, and bisulfite sequencing). These epigenetic aberrations were correlated with transcriptional deregulation of the neighboring candidate tumor suppressor genes, suggesting a coregulation in cis of this gene cluster. We found that the 13q14.3 genes in addition to their previously known functions regulate NF-kB activity, which we could show after overexpression, siRNA-mediated knockdown, and dominant-negative mutant genes by using Western blots with previously undescribed antibodies, by a customized ELISA as well as by reporter assays. In addition, we performed an unbiased screen of 810 human miRNAs and identified the miR-15/16 family of genes at 13q14.3 as the strongest inducers of NF-kB activity. In summary, the tumor suppressor mechanism at 13q14.3 is a cluster of genes controlled by two lncRNA genes that are regulated by DNA-methylation and histone modifications and whose members all regulate NF-kB. Therefore, the tumor suppressor mechanism in 13q14.3 underlines the role both of epigenetic aberrations and of lncRNA genes in human tumorigenesis and is an example of colocalization of a functionally related gene cluster.
    Type of Publication: Journal article published
    PubMed ID: 23593011
    Signatur Availability
    BibTip Others were also interested in ...
  • 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
    Signatur Availability
    BibTip Others were also interested in ...
  • 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
    Signatur Availability
    BibTip Others were also interested in ...
  • 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
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...