Epigenetic silencing of tumor suppressor miR-124 directly promotes STAT3 activation in Cutaneous T-cell Lymphoma
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PROVIDER: PRJNA541501 | ENA |
REPOSITORIES: ENA
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Project description:Increasing evidences support a potential role for the Signal Transducer and Activator of Transcription-3 (STAT3) as a tumor driver in cutaneous T-cell lymphoma (CTCL). However, the mechanisms leading to STAT3 pathway activation in CTCL and how STAT3 activation contributes to lymphomagenesis remains primarily not enough explored. Recently, we found that miR-124, a known STAT3 regulator in cancer, is robustly silenced in Mycosis Fungoides (MF) tumor-stage and CTCL cell lines and we have herein studied whether deregulation of miR-124 contributes to activate STAT3 pathway in CTCL. Material and Methods: DNA methylation status of miR-124 and its expression levels in response to the DNA-demethylating agent azacitidine were evaluated in CTCL cell lines by pyrosequencing analysis. CTCL cell lines were transient transfected with a lentiviral vector encoding miR-124 and transfected cells were analyzed for phosphorylated STAT3 (P-STAT3) levels. The impact on STAT3 signaling was evaluated using expression microarray on CTCL cell lines in both conditions, miR-124 absent (malignant condition) versus miR-124 expressed (lentiviral transduction). Results: A significant promoter methylation and silencing of miR-124 in MF tumor samples and CTCL cell lines was detected. DNA methylation levels of miR-124 in CTCL cell lines were restored (and subsequently miR-124 were overexpressed) after DNA demethylation. Ectopic lentiviral expression of miR-124 downregulated STAT3 in the different CTCL cell lines. Genes differentially expressed regarding miR-124 regulation in CTCL cell lines indicated impact on known cell survival and function pathways and, particularly, intervention on miR-124 expression modulated different STAT3 pathway components. Conclusions: Our study deciphers a novel epigenetic mechanisms regulating STAT3 pathway in CTCL. This might contribute to a better understanding the molecular basis in CTCL development. Deregulation of STAT3 seems to have a major impact on cell survival in CTCL cell lines indicating the potential interest of targeting STAT3 with specific therapies.
2020-12-31 | GSE130809 | GEO
Project description:Increasing evidence supports a potential role for STAT3 as a tumor driver in cutaneous T-cell lymphomas (CTCL). The mechanisms leading to STAT3 activation are not fully understood; however, we recently found that miR-124, a known STAT3 regulator, is robustly silenced in MF tumor-stage and CTCL cells. We studied here whether deregulation of miR-124 contributes to STAT3 pathway activation in CTCL. We measured the effect of ectopic mir-124 expression in active phosphorylated STAT3 (p-STAT3) levels and evaluated the transcriptional impact of miR-124-dependent STAT3 pathway regulation by expression microarray analysis. We found that ectopic expression of miR-124 results in massive downregulation of activated STAT3 in different CTCL lines, which resulted in a significant alteration of genetic signatures related with gene transcription and proliferation such as MYC and E2F. Our study highlights the importance of the miR-124/STAT3 axis in CTCL and demonstrates that the STAT3 pathway is regulated through epigenetic mechanisms in these cells. Since deregulated STAT3 signaling has a major impact on CTCL initiation and progression, a better understanding of the molecular basis of the miR-124/STAT3 axis may provide useful information for future personalized therapies.
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Project description:Squamous cell carcinoma is the second most common skin cancer and frequently progress from an intraepithelial actinic keratosis. The role of microRNAs during the progression from actinic keratosis to cutaneous squamous cell carcinoma (cSCC) remains to be elicited. By using an Agilent microRNA expression microarray we found the expression of miR-204 to be markedly downregulated in cSCC when compared to actinic keratoses. DNA methylation of the TRPM3 promoter region upstream of miR-204-5p was identified as one of the repressive mechanisms that accounts for miR-204 silencing in cSCC. Functional studies on HaCaT cells revealed that this microRNA downregulates the Signal Transducer and Activator of Transcription 3 (STAT3) pathway and favours the MAPK signaling pathway, likely acting through PTPN11, a tyrosine phosphatase that is a direct miR-204 target. We found that activated STAT3, as detected by pY705-STAT3 immunofluorescence, is retained in the membrane and cytoplasm compartment in AK, whereas cSCC displayed STAT3 in the nuclei. Taken together, our data indicates that MiR-204 may act as a “rheostat” that controls the signaling towards the MAPK pathway or the STAT3 pathway.
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Project description:This time course analysis is to study the targets and functions of miR-124. MiR-124 was overexpressed and the effect of miR-124 overexpression was compared to negative controls to identify downregulated genes and potential miRNA targets. Keywords: time course
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Project description:This phase I trial studies how well an imaging agent called I-124 M5A works in detecting CEA-positive colorectal cancer that has spread to the liver. I-124 M5A is a monoclonal antibody, called M5A, linked to a radioactive substance called I-124. M5A binds to CEA-positive cancer cells and may, through imaging scans, be able to detect liver metastases by picking up signals from I-124.
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Project description:Neuron-enriched microRNAs (miRNAs), miR-9/9* and miR-124 (miR-9/9*-124), direct cell fate switching of human fibroblasts to neurons when ectopically expressed by repressing anti-neurogenic genes. How these miRNAs function after the onset of the transcriptome switch to a neuronal fate remains unclear. Here, we identified direct targets of miRNAs by Argonaute (AGO) HITS-CLIP as reprogramming cells activate the neuronal program and reveal the role of miR-124 that directly promotes the expression of its target genes associated with neuronal development and function.
2021-05-25 | GSE161240 | GEO
Project description:Neuron-enriched microRNAs (miRNAs), miR-9/9* and miR-124 (miR-9/9*-124), direct cell fate switching of human fibroblasts to neurons when ectopically expressed by repressing anti-neurogenic genes. How these miRNAs function after the onset of the transcriptome switch to a neuronal fate remains unclear. Here, we identified direct targets of miRNAs by Argonaute (AGO) HITS-CLIP as reprogramming cells activate the neuronal program and reveal the role of miR-124 that directly promotes the expression of its target genes associated with neuronal development and function.
2021-05-25 | GSE161239 | GEO
Project description:Neuron-enriched microRNAs (miRNAs), miR-9/9* and miR-124 (miR-9/9*-124), direct cell fate switching of human fibroblasts to neurons when ectopically expressed by repressing anti-neurogenic genes. How these miRNAs function after the onset of the transcriptome switch to a neuronal fate remains unclear. Here, we identified direct targets of miRNAs by Argonaute (AGO) HITS-CLIP as reprogramming cells activate the neuronal program and reveal the role of miR-124 that directly promotes the expression of its target genes associated with neuronal development and function.
2021-05-25 | GSE161238 | GEO
Project description:Stat3 has been acknowledged as an oncogene that has dual protumorigenic activity in a cell-intrinsic way, by promoting cancer cell proliferation and survival and in a paracrine mode, acting as suppressor of immune cell attack. We demonstrated that Stat3 silencing with a small interfering RNA (siRNA) induced a senescence program in Stat3-addicted cancer cells and leads to the production of a senescence associated secretory phenotype (SASP) that has several antitumor properties. The composition of the SASP induced by Stat3 silencing is poorly characterized. The goal of the project was to analyze the protein content in the secretome released by the mouse breast cancer cell line 4T1 after Stat3 silencing with a small interfering RNA.
2020-01-21 | PXD013948 | Pride