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AATF/Che-1 localizes to paraspeckles and suppresses R-loops accumulation and interferon activation in Multiple Myeloma.

ABSTRACT: Several kinds of stress promote the formation of three-stranded RNA:DNA hybrids called R-loops. Insufficient clearance of these structures promotes genomic instability and DNA damage, which ultimately contribute to the establishment of cancer phenotypes. Paraspeckle assemblies participate in R-loop resolution and preserve genome stability, however, the main determinants of this mechanism are still unknown. This study finds that in Multiple Myeloma (MM), AATF/Che-1 (Che-1), an RNA-binding protein fundamental to transcription regulation, interacts with paraspeckles via the lncRNA NEAT1_2 (NEAT1) and directly localizes on R-loops. We systematically show that depletion of Che-1 produces a marked accumulation of RNA:DNA hybrids. We provide evidence that such failure to resolve R-loops causes sustained activation of a systemic inflammatory response characterized by an interferon (IFN) gene expression signature. Furthermore, elevated levels of R-loops and of mRNA for paraspeckle genes in patient cells are linearly correlated with Multiple Myeloma progression. Moreover, increased interferon gene expression signature in patients is associated with markedly poor prognosis. Taken together, our study indicates that Che-1/NEAT1 cooperation prevents excessive inflammatory signaling in Multiple Myeloma by facilitating the clearance of R-loops. Further studies on different cancer types are needed to test if this mechanism is ubiquitously conserved and fundamental for cell homeostasis.

SUBMITTER: Dr. Tiziana Bruno

PROVIDER: S-SCDT-EMBOJ-2021-109711 | biostudies-other |

REPOSITORIES: biostudies-other

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AATF/Che-1 localizes to paraspeckles and suppresses R-loops accumulation and interferon activation in Multiple Myeloma

Project description:We investigated the interactions of AATF/Che1 with paraspeckles complex in Multiple Myeloma(MM) cells by looking at its relationship with lncRNA NEAT1_1(NEAT1) and the essential paraspeckles proteins. By analyzing ChIP- and ChIRP-sequencing of MM cells, we assessed that the interaction between AATF/Che1 and NEAT1 occurs also onto DNA and detected the sites where they co-localize. To better characterize the interaction, we studied the effects of interfering AATF/Che1 or NEAT1 on co-localizing sites through ChIP-seq with NEAT1 interfered (GapmerNEAT1) and ChIRP-seq with AATF/Che1 interfered (siChe). We found that NEAT1 is essential in maintaining the paraspeckles complex onto those sites. Moreover, by exploring DRIP-seq data with siChe, we also detected that AATF/Che1 and NEAT1 localize on R-loops, RNA:DNA hybrid structure involved in DNA transcription and repair. A depletion of AATF/Che1 causes a further increase of those hybrid structures and the activation of the immune response in MM, in particular the interferon (IFN) activation. To further explore these findings, we performed RNA-seq with siChe and GapmerNEAT1 which confirm that AATF/Che-1 down-regulation induces a strong up-regulation of genes involved in IFN response.

2022-07-06 | GSE178868 | GEO

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Multiple myeloma

Project description:Multiple myeloma

| PRJNA515992 | ENA

Circ-SMARCA5 suppresses progression of multiple myeloma by targeting miR-767-5p.

Project description:BackgroundWe aimed to investigate the correlation of Circ-SMARCA5 with disease severity and prognosis in multiple myeloma (MM), and its underlying mechanisms in regulating cell proliferation and apoptosis.MethodsBone marrow samples from 105 MM patients and 36 healthy controls were collected for Circ-SMARCA5 expression measurement. And the correlation of Circ-SMARCA5 expression with patients' characteristics and survival was determined. In vitro, the effect of Circ-SMARCA5 on MM cell proliferation and apoptosis was evaluated by altering Circ-SMARCA5 expression through transfection. Rescue experiments and luciferase assay were further performed to explore the mechanism of Circ-SMARCA5 as well as its potential target miR-767-5p in regulating MM cell activity.ResultsCirc-AMARCA5 was downregulated in MM and presented a good value in distinguishing MM patients from controls and it was also negatively correlated with Beta-2-microglobulin (β2-MG) level and International Staging System (ISS) stage. Additionally, Circ-SMARCA5 high expression was associated with higher CR as well as better PFS and OS. As for in vitro experiments, Circ-SMARCA5 expression was lower in MM cell lines compared with normal cells, and Circ-SMARCA5 overexpression inhibited cell proliferation but promoted cell apoptosis in RPMI8226 cells. Rescue experiments disclosed that the effect of Circ-SMARCA5 on cell activity was attenuated by miR-767-5p, and luciferase reporter assay revealed direct binding between Circ-SMARCA5 and miR-767-5p.ConclusionsCirc-SMARCA5 is downregulated and correlated with lower β2-MG level and ISS stage as well as better prognosis in MM patients, and it inhibits proliferation but promotes apoptosis of MM cells via directly sponging miR-767-5p.

| S-EPMC6785934 | biostudies-literature

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| S-EPMC6159960 | biostudies-literature

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