ADAR1 regulates melanoma progression via miRNAs biogenesis
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
SUBMITTER: jacob jasmine
PROVIDER: S-ECPF-GEOD-31963 | biostudies-other |
REPOSITORIES: biostudies-other
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Project description:Aberrant RNA-editing was observed in several human tumors, but its significance is mostly unknown. Here we show that ADAR1, a ubiquitous RNA-editing enzyme, is commonly lost in metastatic melanoma cells and specimens. Experimental ADAR1 silencing significantly alters melanoma cell morphology, facilitates proliferation and cell-cycle, and increases the tumorigenicity in-vivo. A series of ADAR1 truncation mutants establishes a novel RNA-editing-independent role for ADAR1 in controlling the nuclear and cytoplasmic processing steps of miRNA biogenesis. Altered expression of ADAR1-controled miRNAs accounts for the observed phenotype. We show that the oncogenic miR-17-5p endogenously regulates ADAR1 expression and that its genomic sequence is frequently amplified in melanoma to overexpress the mature miR-17-5p form. ADAR1 and miR-17-5p are ubiquitously expressed, suggesting the generality of this mechanism. Melanoma cell line expressing low ADAR1 levels (ADAR1-Knockdown) using shRNA technique were selected for RNA extraction and hybridization on Affymetrix microarrays. We sought to examine the alterations in the genes and microRNA expression profile in the manipulated cell system, due to ADAR1 possible involvement cancer development. To that end, we selected ADAR1-knockdown (ADAR1-KD) cells that demonstrated an enhanced aggressive phenotype both in vivo and in vitro as compared to the control cells (Control).
2012-08-31 | E-GEOD-31963 | biostudies-arrayexpress
Project description:Aberrant RNA-editing was observed in several human tumors, but its significance is mostly unknown. Here we show that ADAR1, a ubiquitous RNA-editing enzyme, is commonly lost in metastatic melanoma cells and specimens. Experimental ADAR1 silencing significantly alters melanoma cell morphology, facilitates proliferation and cell-cycle, and increases the tumorigenicity in-vivo. A series of ADAR1 truncation mutants establishes a novel RNA-editing-independent role for ADAR1 in controlling the nuclear and cytoplasmic processing steps of miRNA biogenesis. Altered expression of ADAR1-controled miRNAs accounts for the observed phenotype. We show that the oncogenic miR-17-5p endogenously regulates ADAR1 expression and that its genomic sequence is frequently amplified in melanoma to overexpress the mature miR-17-5p form. ADAR1 and miR-17-5p are ubiquitously expressed, suggesting the generality of this mechanism.
2012-08-31 | GSE31963 | GEO
Project description:Melanoma cells utilize multiple mechanisms to exit the primary tumor mass, invade the surroundings and subsequently distant tissues. We have previously reported that the expression of the RNA editing enzyme ADAR1 (adenosine deaminase acting on RNA) is downregulated in metastatic melanoma, which facilitates proliferation and invasion. Here we show that ADAR1 controls melanoma invasiveness by regulating ITGB3 expression via miR-30a and miR-30d. ADAR1 overexpression or knockdown leads to an increase or decrease, respectively, in the expression of both microRNAs. The effect is independent of RNA-editing. Dual luciferase assays show that both microRNAs directly regulate the expression of the ITGB3 integrin. Overexpression of the miR-30a or miR-30d lead to a decrease in ITGB3 and a resultant decreased invasive and metastatic capacities. Neutralization of the endogenous miR-30a or miR-30d leads to the opposite effect. The microRNAs regulate ITGB3 levels probably through a post-transcriptional effect, as both mRNA and protein levels of ITGB3 are affected. These results further expand our knowledge on the ADAR1-ITGB3 network and its central role in acquisition of the invasive phenotype of metastatic melanoma.
| S-EPMC7471345 | biostudies-literature
Project description:The blossom of immunotherapy in melanoma highlights the need to delineate mechanisms of immune resistance. Recently, we have demonstrated that the RNA editing protein, adenosine deaminase acting on RNA-1 (ADAR1) is down-regulated during metastatic transition of melanoma, which enhances melanoma cell proliferation and tumorigenicity. Here we investigate the role of ADAR1 in melanoma immune resistance. Importantly, knockdown of ADAR1 in human melanoma cells induces resistance to tumor infiltrating lymphocytes in a cell contact-dependent mechanism. We show that ADAR1, in an editing-independent manner, regulates the biogenesis of miR-222 at the transcription level and thereby Intercellular Adhesion Molecule 1 (ICAM1) expression, which consequently affects melanoma immune resistance. ADAR1 thus has a novel, pivotal, role in cancer immune resistance. Corroborating with these results, the expression of miR-222 in melanoma tissue specimens was significantly higher in patients who had no clinical benefit from treatment with ipilimumab as compared to patients that responded clinically, suggesting that miR-222 could function as a biomarker for the prediction of response to ipilimumab. These results provide not only novel insights on melanoma immune resistance, but also pave the way to the development of innovative personalized tools to enable optimal drug selection and treatment. 13 formalin fixed paraffin embedded (FFPE) melanoma tissues were stained with hematoxilin and eosin for examination by an expert pathologist. Non-tumor tissue was removed. Total RNA was isolated using miRNeasy FFPE kit (Qiagen) according to the manufacture guidelines.
2015-12-31 | E-GEOD-67496 | biostudies-arrayexpress
Project description:Adenosine deaminases acting on RNA 1 (ADAR1) catalyzes cellular RNA adenosine-to-inosine editing events on structured RNA molecules. In line with this critical role, ADAR1 exhibits ubiquitous expression and is essential for embryonic development. However, regulation and developmental significance of this RNA editor in a spatiotemporal context are largely elusive. Here we unveil a novel tissue-specific role of ADAR1 in skeletal myogenesis. ADAR1 expression displayed programmed alteration that is coordinated with differentiation cues, and mediated negatively by miRNA-1/206. Coincidently, ADAR1 exerts stage-dependent functions-suppression of apoptosis at the onset of differentiation and preservation of timely myotube formation through later phase. Furthermore, the post-transcriptional aspect of its myogenic role was illustrated by the spectrum of binding RNAs, as revealed by high-throughput approach, as well as by direct regulation of myogenesis-associated targets such as dynamin 1/2 (Dnm1/2) and annexin A4. Consequently, maintenance of target gene expression profiles likely contributes to a state of cytoskeleton and membrane dynamics that is amenable to myoblast morphogenesis. Collectively, these findings uncover a critical link of ADAR1 to myogenesis, and further highlight an epigenetic mechanism by which ADAR1 and miR-1/206 interplay to control scheduled myoblast-myotube transition.
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Project description:Melanoma cells use different migratory strategies to exit the primary tumor mass and invade surrounding and subsequently distant tissues. We reported previously that ADAR1 expression is downregulated in metastatic melanoma, thereby facilitating proliferation. Here we show that ADAR1 silencing enhances melanoma cell invasiveness and ITGB3 expression. The enhanced invasion is reversed when ITGB3 is blocked with antibodies. Re-expression of wild-type or catalytically inactive ADAR1 establishes this mechanism as independent of RNA editing. We demonstrate that ADAR1 controls ITGB3 expression both at the post-transcriptional and transcriptional levels, via miR-22 and PAX6 transcription factor, respectively. These are proven here as direct regulators of ITGB3 expression. miR-22 expression is controlled by ADAR1 via FOXD1 transcription factor. Clinical relevance is demonstrated in patient-paired progression tissue microarray using immunohistochemistry. The novel ADAR1-dependent and RNA-editing-independent regulation of invasion, mediated by ITGB3, strongly points to a central involvement of ADAR1 in cancer progression and metastasis.
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Project description:The blossom of immunotherapy in melanoma highlights the need to delineate mechanisms of immune resistance. Recently, we have demonstrated that the RNA editing protein, adenosine deaminase acting on RNA-1 (ADAR1) is down-regulated during metastatic transition of melanoma, which enhances melanoma cell proliferation and tumorigenicity. Here we investigate the role of ADAR1 in melanoma immune resistance. Importantly, knockdown of ADAR1 in human melanoma cells induces resistance to tumor infiltrating lymphocytes in a cell contact-dependent mechanism. We show that ADAR1, in an editing-independent manner, regulates the biogenesis of miR-222 at the transcription level and thereby Intercellular Adhesion Molecule 1 (ICAM1) expression, which consequently affects melanoma immune resistance. ADAR1 thus has a novel, pivotal, role in cancer immune resistance. Corroborating with these results, the expression of miR-222 in melanoma tissue specimens was significantly higher in patients who had no clinical benefit from treatment with ipilimumab as compared to patients that responded clinically, suggesting that miR-222 could function as a biomarker for the prediction of response to ipilimumab. These results provide not only novel insights on melanoma immune resistance, but also pave the way to the development of innovative personalized tools to enable optimal drug selection and treatment.
2015-12-31 | GSE67496 | GEO
Project description:In a murine melanoma model, malignant transformation promoted by a sustained stress condition was causally related to increased levels of reactive oxygen species resulting in DNA damage and massive epigenetic alterations. Since the chromatin modifier Sirtuin-1 (SIRT1) is a protein attracted to double-stranded DNA break (DSB) sites and can recruit other components of the epigenetic machinery, we aimed to define the role of SIRT1 in melanomagenesis through our melanoma model. The DNA damage marker, ?H2AX was found increased in melanocytes after 24 hours of deadhesion, accompanied by increased SIRT1 expression and decreased levels of its target, H4K16ac. Moreover, SIRT1 started to be associated to DNMT3B during the stress condition, and this complex was maintained along malignant progression. Mxd1 was identified by ChIP-seq among the DNA sequences differentially associated with SIRT1 during deadhesion and was shown to be a common target of both, SIRT1 and DNMT3B. In addition, Mxd1 was found downregulated from pre-malignant melanocytes to metastatic melanoma cells. Treatment with DNMT inhibitor 5AzaCdR reversed the Mxd1 expression. Sirt1 stable silencing increased Mxd1 mRNA expression and led to down-regulation of MYC targets, such as Cdkn1a, Bcl2 and Psen2, whose upregulation is associated with human melanoma aggressiveness and poor prognosis. We demonstrated a novel role of the stress responsive protein SIRT1 in malignant transformation of melanocytes associated with deadhesion. Mxd1 was identified as a new SIRT1 target gene. SIRT1 promoted Mxd1 silencing, which led to increased activity of MYC oncogene contributing to melanoma progression.
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