| 1. |
- Pandey, Gaurav Kumar, et al.
(författare)
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The risk-associated long noncoding RNA NBAT-1 controls neuroblastoma progression by regulating cell proliferation and neuronal differentiation.
- 2014
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Ingår i: Cancer Cell. - : Elsevier BV. - 1535-6108 .- 1878-3686. ; 26:5, s. 722-737
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Tidskriftsartikel (refereegranskat)abstract
- Neuroblastoma is an embryonal tumor of the sympathetic nervous system and the most common extracranial tumor of childhood. By sequencing transcriptomes of low- and high-risk neuroblastomas, we detected differentially expressed annotated and nonannotated long noncoding RNAs (lncRNAs). We identified a lncRNA neuroblastoma associated transcript-1 (NBAT-1) as a biomarker significantly predicting clinical outcome of neuroblastoma. CpG methylation and a high-risk neuroblastoma associated SNP on chromosome 6p22 functionally contribute to NBAT-1 differential expression. Loss of NBAT-1 increases cellular proliferation and invasion. It controls these processes via epigenetic silencing of target genes. NBAT-1 loss affects neuronal differentiation through activation of the neuronal-specific transcription factor NRSF/REST. Thus, loss of NBAT-1 contributes to aggressive neuroblastoma by increasing proliferation and impairing differentiation of neuronal precursors.
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| 2. |
- Subhash, Santhilal, 1987, et al.
(författare)
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H3K4me2 and WDR5 enriched chromatin interacting long non-coding RNAs maintain transcriptionally competent chromatin at divergent transcriptional units
- 2018
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Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP). - 0305-1048 .- 1362-4962. ; 46:18, s. 9384-9400
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Tidskriftsartikel (refereegranskat)abstract
- Recently lncRNAs have been implicated in the sub-compartmentalization of eukaryotic genome via genomic targeting of chromatin remodelers. To explore the function of lncRNAs in the maintenance of active chromatin, we characterized lncRNAs from the chromatin enriched with H3K4me2 and WDR5 using chromatin RNA immunoprecipitation (ChRIP). Significant portion of these enriched lncRNAs were arranged in antisense orientation with respect to their protein coding partners. Among these, 209 lncRNAs, commonly enriched in H3K4me2 and WDR5 chromatin fractions, were named as active chromatin associated lncRNAs (active lncCARs). Interestingly, 43% of these active lncCARs map to divergent transcription units. Divergent transcription (XH) units were overrepresented in the active lncCARs as compared to the inactive lncCARs. ChIP-seq analysis revealed that active XH transcription units are enriched with H3K4me2, H3K4me3 and WDR5. WDR5 depletion resulted in the loss of H3K4me3 but not H3K4me2 at the XH promoters. Active XH CARs interact with and recruit WDR5 to XH promoters, and their depletion leads to decrease in the expression of the corresponding protein coding genes and loss of H3K4me2, H3K4me3 and WDR5 at the active XH promoters. This study unravels a new facet of chromatin-based regulation at the divergent XH transcription units by this newly identified class of H3K4me2/WDR5 chromatin enriched lncRNAs.
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| 3. |
- Ali, Mohamad Moustafa, et al.
(författare)
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PAN-cancer analysis of S-phase enriched lncRNAs identifies oncogenic drivers and biomarkers
- 2018
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Despite improvement in our understanding of long noncoding RNAs (lncRNAs) role in cancer, efforts to find clinically relevant cancer-associated lncRNAs are still lacking. Here, using nascent RNA capture sequencing, we identify 1145 temporally expressed S-phase-enriched lncRNAs. Among these, 570 lncRNAs show significant differential expression in at least one tumor type across TCGA data sets. Systematic clinical investigation of 14 Pan-Cancer data sets identified 633 independent prognostic markers. Silencing of the top differentially expressed and clinically relevant S-phase-enriched lncRNAs in several cancer models affects crucial cancer cell hallmarks. Mechanistic investigations on SCAT7 in multiple cancer types reveal that it interacts with hnRNPK/YBX1 complex and affects cancer cell hallmarks through the regulation of FGF/FGFR and its downstream PI3K/AKT and MAPK pathways. We also implement a LNA-antisense oligo-based strategy to treat cancer cell line and patient-derived tumor (PDX) xenografts. Thus, this study provides a comprehensive list of lncRNA-based oncogenic drivers with potential prognostic value.
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| 4. |
- Djos, Anna, 1983, et al.
(författare)
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Telomere Maintenance Mechanisms in a Cohort of High-Risk Neuroblastoma Tumors and Its Relation to Genomic Variants in the TERT and ATRX Genes
- 2023
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Ingår i: CANCERS. - 2072-6694. ; 15:24
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Tidskriftsartikel (refereegranskat)abstract
- Tumor cells are hallmarked by their capacity to undergo unlimited cell divisions, commonly accomplished either by mechanisms that activate TERT or through the alternative lengthening of telomeres pathway. Neuroblastoma is a heterogeneous pediatric cancer, and the aim of this study was to characterize telomere maintenance mechanisms in a high-risk neuroblastoma cohort. All tumor samples were profiled with SNP microarrays and, when material was available, subjected to whole genome sequencing (WGS). Telomere length was estimated from WGS data, samples were assayed for the ALT biomarker c-circles, and selected samples were subjected to methylation array analysis. Samples with ATRX aberration in this study were positive for c-circles, whereas samples with either MYCN amplification or TERT re-arrangement were negative for c-circles. Both ATRX aberrations and TERT re-arrangement were enriched in 11q-deleted samples. An association between older age at diagnosis and 1q-deletion was found in the ALT-positive group. TERT was frequently placed in juxtaposition to a previously established gene in neuroblastoma tumorigenesis or cancer in general. Given the importance of high-risk neuroblastoma, means for mitigating active telomere maintenance must be therapeutically explored.
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| 5. |
- Jin, L. Y., et al.
(författare)
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Long noncoding RNA MEG3 regulates LATS2 by promoting the ubiquitination of EZH2 and inhibits proliferation and invasion in gallbladder cancer
- 2018
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Ingår i: Cell Death & Disease. - : Springer Science and Business Media LLC. - 2041-4889. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Gallbladder cancer (GBC) is the most common type of biliary tract cancer worldwide. Long noncoding RNAs (lncRNAs) play essential roles in physiological and pathological development. LncRNA MEG3, a tumor suppressor, has been reported to play important roles in some cancers, but the role of MEG3 in GBC remains largely unknown. The purpose of the present study was to explore the role of MEG3 in proliferation and invasion and the potential molecular mechanism in GBC. We found that MEG3 was downregulated in GBC tissues and cells, and low expression of MEG3 was correlated with poor prognostic outcomes in patients. Overexpression of MEG3 inhibited GBC cell proliferation and invasion, induced cell apoptosis and decreased tumorigenicity in nude mice. Moreover, we found that MEG3 was associated with EZH2 and attenuated EZH2 by promoting its ubiquitination. Furthermore, MEG3 executed its functions via EZH2 to regulate the downstream target gene LATS2. Taken together, these findings suggest that MEG3 is an effective target for GBC therapy and may facilitate the development of lncRNA-directed diagnostics and therapeutics against GBC.
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| 6. |
- Juvvuna, Prasanna Kumar, et al.
(författare)
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NBAT1/CASC15-003/USP36 control MYCN expression and its downstream pathway genes in neuroblastoma.
- 2021
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Ingår i: Neuro-oncology advances. - : Oxford University Press (OUP). - 2632-2498. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- MYCN has been an attractive therapeutic target in neuroblastoma considering the widespread amplification of the MYCN locus in neuroblastoma, and its established role in neuroblastoma development and progression. Thus, understanding neuroblastoma-specific control of MYCN expression at the transcriptional and post-transcriptional level would lead to identification of novel MYCN-dependent oncogenic pathways and potential therapeutic strategies.By performing loss- and gain-of-function experiments of the neuroblastoma hotspot locus 6p22.3 derived lncRNAs CASC15-003 and NBAT1, together with coimmunoprecipitation and immunoblotting of MYCN, we have shown that both lncRNAs post-translationally control the expression of MYCN through regulating a deubiquitinase enzyme USP36. USP36 oncogenic properties were investigated using cancer cell lines and in vivo models. RNA-seq analysis of loss-of-function experiments of CASC15-003/NBAT1/MYCN/USP36 and JQ1-treated neuroblastoma cells uncovered MYCN-dependent oncogenic pathways.We show that NBAT1/CASC15-003 control the stability of MYCN protein through their common interacting protein partner USP36. USP36 harbors oncogenic properties and its higher expression in neuroblastoma patients correlates with poor prognosis, and its downregulation significantly reduces tumor growth in neuroblastoma cell lines and xenograft models. Unbiased integration of RNA-seq data from CASC15-003, NBAT1, USP36, and MYCN knockdowns and neuroblastoma cells treated with MYCN inhibitor JQ1, identified genes that are jointly regulated by the NBAT1/CASC15-003/USP36/MYCN pathway. Functional experiments on one of the target genes, COL18A1, revealed its role in the NBAT1/CASC15-003-dependent cell adhesion feature in neuroblastoma cells.Our data show post-translational regulation of MYCN by NBAT1/CASC15-003/USP36, which represents a new regulatory layer in the complex multilayered gene regulatory network that controls MYCN expression.
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| 7. |
- Khan, M. I., et al.
(författare)
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Impact of the double mutants on spike protein of SARS-CoV-2 B.1.617 lineage to the human ACE2 receptor binding: A structural insight
- 2021
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Ingår i: Viruses. - : MDPI AG. - 1999-4915. ; 13:11
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Tidskriftsartikel (refereegranskat)abstract
- The recent emergence of novel SARS-CoV-2 variants has threatened the efforts to contain the COVID-19 pandemic. The emergence of these “variants of concern” has increased viral transmissibility or immune escape and has supplanted the ancestral strains. The novel variants harbored by the B.1.617 lineage (Kappa and Delta) carry mutations within the receptor-binding domain of spike (S) protein (L452R + E484Q and L452R + T478K), the region binding to the host receptor. The double mutations carried by these novel variants are primarily responsible for an upsurge number of COVID-19 cases in India. In this study, we thoroughly investigated the impact of these double mutations on the binding capability to the human host receptor. We performed several structural analyses and found that the studied double mutations increase the binding affinity of the spike protein to the human host receptor (ACE2). Furthermore, our study showed that these double mutants might be a dominant contributor enhancing the receptor-binding affinity of SARS-CoV-2 and consequently making it more stable. We also investigated the impact of these mutations on the binding affinity of two monoclonal antibodies (Abs) (2-15 and LY-CoV555) and found that the presence of the double mutations also hinders its binding with the studied Abs. The principal component analysis, free energy landscape, intermolecular interaction, and other investigations provided a deeper structural insight to better understand the molecular mechanism responsible for increased viral transmissibility of these variants. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
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| 8. |
- Mitra, Sanhita, et al.
(författare)
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Subcellular distribution of p53 by the p53-responsive lncRNA NBAT1 determines chemotherapeutic response in neuroblastoma.
- 2021
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Ingår i: Cancer research. - 1538-7445. ; 81:6, s. 1457-1471
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Tidskriftsartikel (refereegranskat)abstract
- Neuroblastoma has a low mutation rate for the p53 gene. Alternative ways of p53 inactivation have been proposed in neuroblastoma, such as abnormal cytoplasmic accumulation of wild-type p53. However, mechanisms leading to p53 inactivation via cytoplasmic accumulation are not well investigated. Here we show that the neuroblastoma risk-associated locus 6p22.3-derived tumor suppressor NBAT1 is a p53-responsive lncRNA that regulates p53 subcellular levels. Low expression of NBAT1 provided resistance to genotoxic drugs by promoting p53 accumulation in cytoplasm and loss from mitochondrial and nuclear compartments. Depletion of NBAT1 altered CRM1 function and contributed to the loss of p53-dependent nuclear gene expression during genotoxic drug treatment. CRM1 inhibition rescued p53-dependent nuclear functions and sensitized NBAT1-depleted cells to genotoxic drugs. Combined inhibition of CRM1 and MDM2 was even more effective in sensitizing aggressive neuroblastoma cells with p53 cytoplasmic accumulation. Thus, our mechanistic studies uncover an NBAT1-dependent CRM1/MDM2-based potential combination therapy for high-risk neuroblastoma patients.
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| 9. |
- Mondal, Tanmoy, 1981, et al.
(författare)
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Chromatin RNA Immunoprecipitation (ChRIP).
- 2017
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Ingår i: Methods in molecular biology. - New York, NY : Humana Press. - 1940-6029. - 9781493973798 ; , s. 65-76
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Bokkapitel (refereegranskat)abstract
- Researchers have recently had a growing interest in understanding the functional role of long noncoding RNAs (lncRNAs) in chromatin organization. Accumulated evidence suggests lncRNAs could act as interphase molecules between chromatin and chromatin remodelers to define the epigenetic code. However, it is not clear how lncRNAs target chromatin remodelers to specific chromosomal regions in order to establish a functionally distinct epigenetic state of chromatin. We developed and optimized chromatin RNA immunoprecipitation (ChRIP) technology to characterize the lncRNAs associated with active and inactive chromatin compartments. Use of ChRIP to identify chromatin-bound lncRNA will further improve our knowledge regarding the functional role of lncRNAs in establishing epigenetic modifications of chromatin.
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| 10. |
- Mondal, Tanmoy, 1981-
(författare)
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Epigenetic Regulation by Noncoding RNA
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- High throughput transcriptomic analyses have realized us with the fact that eukaryotic genome encodes thousands of noncoding RNAs (ncRNAs) with unknown function. In my thesis, I sought to address epigenetic regulation of transcription by ncRNA using the Kcnq1 imprinted cluster as a model system. Genomic imprinting is an epigenetic phenomenon whereby one of the parental alleles is silenced by epigenetic mechanism in a parent of origin-specific manner. A long ncRNA Kcnq1ot1 regulates imprinting of nearly 8 protein coding genes in the Kcnq1 imprinted cluster. Expression of Kcnq1ot1 is restricted to the paternal chromosome while that of protein-coding genes to the maternal chromosome. Kcnq1ot1 is a 91kb long, moderately stable, nuclear localized and RNAPII encoded transcript. We demonstrated that Kcnq1ot1 RNA itself mediates lineage specific silencing on the paternal chromosome by interacting with chromatin and recruiting the repressive chromatin modifiers to the imprinted gene promoters. Previously we identified an 890bp silencing domain (SD) at the 5´end of the Kcnq1ot1 RNA which is responsible for gene silencing. Targeted deletion of the 890SD in mouse resulted in specific loss of silencing of ubiquitously imprinted genes. We have further shown that Kcnq1ot1 interacts with Dnmt1 and recruit Dnmt1 at the somatic DMRs flanking some of the ubiquitously imprinted genes. We next addressed the stability of the Kcnq1ot1 mediated epigenetic silencing using transgenic mouse where we have conditionally deleted the Kcnq1ot1 RNA at different developmental stages and we found that Kcnq1ot1 RNA is required to maintain the silencing of the ubiquitously imprinted genes. In addition, DNA methylation, which controls imprinting of the ubiquitous genes require Kcnq1ot1 for its maintenance. To characterize the ncRNAs that mediate gene regulation through chromatin interaction we have isolated chromatin associated RNAs (CARs) from sucrose gradient fractioned chromatin. High-throughput sequencing of the CARs resulted in the identification of the 141 intronic and 74 intergenic regions harboring CARs. We characterized one of the intergenic CARs which regulate the transcription of the two neighboring genes by modulating the chromatin marks. In summary current thesis has uncovered unprecedented role of ncRNAs in gene expression via chromatin level regulation.
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