Project description:To analysis of the effect of HOTAIR on global DNA methylation in KYSE180 esophageal cancer cell line, genome-scale DNA methylation was analyzed in a pair of esophageal cancer cell lines, KYSE180 cells stably transfected with HOTAIR and control KYSE180 cells. The results from genome-wide DNA methylation analysis indicate that hypermethylation occurs more frequently than hypomethylation after stably ectopic expressing HOTAIR in KYSE180 cells. DNA was quantified by Quant-iT PicoGreen dsDNA Reagent (Invitrogen) and the integrity was analyzed in a 1.3% agarose gel. Bisulfite conversion of 600 ng of each sample was perform according to the manufacture's recommendation for Illumina Infinium Assay. Effective bisulphite conversion was checked for three controls that were converted simultaneously with the samples. 4 ul of bisulfite converted DNA were used to hybridize on Infinium HumanMethylation 450 BeadChip, following Illumina Infinium HD Methylation protocol. Chip analysis was performed using Illumina HiScan SQ fluorescent scanner. The intensities of the images are extracted using GenomeStudio (2010.3) Methylation module (1.8.5) software. Methylation score of each CpG is represented as beta value. For pairwise differential methylation analysis, the difference of two biological replicates of the ESCC cell lines KYSE180 and KYSE180_HOTAIR was calculated.
Project description:To investigate the functional role of HOTAIR in esophageal squanmous cell carcinoma (ESCC) cells, RNAi-mediated knockdown of HOTAIR and overexpression of HOTAIR were carried out using KYSE180 cells. Gene expression microarray analysis revealed that a number of reported HOTAIR target genes were regulated by HOTAIR. Moreover, gene ontology analysis revealed enrichment of genes closely related to tumorigenesis, such as cell migration, regulation of cell cycles. For RNAi-mediated knockdown of HOTAIR, two different stealth siRNAs against HOTAIR were generated by Invitrogen, after which a mixture of the two was used for transfection. KYSE180 cells in 6-well plates were transfected with 100 pmol of Stealth siRNA (Invitrogen) or a Stealth RNAi Negative Control Medium GC (Invitrogen) using Lipofectamine2000 (Invitrogen). For HOTAIR overexpression, KYSE180 cells were transfected with LZRS_HOTAIR vector using Polyfect Transfection Reagent (Qiagen). Total RNA was extracted 48 h after transfection.
Project description:Large intervening noncoding RNAs (lincRNAs) are pervasively transcribed in the genome yet their potential involvement in human disease is not well understood4,5. Recent studies of dosage compensation, imprinting, and homeotic gene expression suggest that individual lincRNAs can function as the interface between DNA and specific chromatin remodeling activities. Here we show that lincRNAs in the HOX loci become systematically dysregulated during breast cancer progression. The lincRNA termed HOTAIR is increased in expression in primary breast tumors and metastases, and HOTAIR expression level in primary tumors is a powerful predictor of eventual metastasis and death. Enforced expression of HOTAIR in epithelial cancer cells induced genome-wide re-targeting of Polycomb Repressive Complex 2 (PRC2) to an occupancy pattern more resembling embryonic fibroblasts, leading to altered histone H3 lysine 27 methylation, gene expression, and increased cancer invasiveness and metastasis in a manner dependent on PRC2. Conversely, loss of HOTAIR can inhibit cancer invasiveness, particularly in cells that possess excessive PRC2 activity. These findings suggest that lincRNAs play active roles in modulating the cancer epigenome and may be important targets for cancer diagnosis and therapy. Comparision of MDA-MB-231 Breast Cancer Cells expressing vector or HOTAIR. Each cell line was subjected to ChIP-chip with anti-H3K27, SUZ12, and EZH2 and interrogated on whole genome promoter arrays
Project description:Accumulating evidence highlights the role of long non-coding RNAs (lncRNA) in cellular homeostasis, and their dysregulation in disease settings. Most lncRNAs function by interacting with proteins or protein complexes. While several orthogonal methods have been developed to identify these proteins, each method has its inherent strengths and limitations. Here, we combine two RNA-centric methods ChIRP-MS and RNA-BioID to obtain a comprehensive list of proteins that interact with the well-known lncRNA HOTAIR. Overexpression of HOTAIR has been associated with a metastasis-promoting phenotype in various cancers. Although HOTAIR is known to bind with PRC2 and LSD1 protein complexes, an unbiased and comprehensive method to map its interactome has not yet been performed. Both ChIRP-MS and RNA-BioID data sets show an association of HOTAIR with mitoribosomes, suggesting HOTAIR has functions independent of its (post-)transcriptional mode-of-action.
Project description:HOTAIR was found to be overepressed in a subset of urothelial cancer tissues and cell lines compared to normal controls. Ectopic HOTAIR expression in urothelial cancer cells in vitro demonstrated cell type dependent changes in phenotype. While some cell lines showed increased proloferation activity and induction of an aggressive phenotypes (e.g. stable transfected VM-CUB1 cells), others displayed rather a reduction of proliferation and migration. Stable transfection of 5637 cells resulted in induction of an immune response. Results of microarray analysis of stable transfected VM-CUB1 and 5637 cells concurred well with observed phenotypical cell type-specific changes. For differential gene expression analyses three independent high quality RNA preparations from VM-CUB1 cells, stably transfected with HOTAIR (clone 20), and 5637 cells, stably transfected with HOTAIR (clone 4), were compared to the respective vector control cells.
Project description:Bromodomain inhibition comprises a promising therapeutic strategy in cancer, particularly for hematologic malignancies. To date, however, genomic biomarkers to direct clinical translation have been lacking. We conducted a cell-based screen of genetically-defined cancer cell lines using a prototypical inhibitor of BET bromodomains. Integration of genetic features with chemosensitivity data revealed a robust correlation between MYCN amplification and sensitivity to bromodomain inhibition. We characterized the mechanistic and translational significance of this finding in neuroblastoma, a childhood cancer with frequent amplification of MYCN. Genome-wide expression analysis demonstrated downregulation of the MYCN transcriptional program accompanied by suppression of MYCN transcription. Functionally, bromodomain-mediated inhibition of MYCN impaired growth and induced apoptosis in neuroblastoma. BRD4 knock-down phenocopied these effects, establishing BET bromodomains as transcriptional regulators of MYCN. BET inhibition conferred a significant survival advantage in three in vivo neuroblastoma models, providing a compelling rationale for developing BET bromodomain inhibitors in patients with neuroblastoma. Significance: Biomarkers of response to small-molecule inhibitors of BET bromodomains, a new compound class with promising anti-cancer activity, have been lacking. Here, we reveal MYCN amplification as a strong genetic predictor of sensitivity to BET bromodomain inhibitors, demonstrate a mechanistic rationale for this finding, and provide a translational framework for clinical trial development of BET bromodomain inhibitors for pediatric patients with MYCN-amplified neuroblastoma. JQ1 is a novel thieno-triazolo-1,4-diazepine, which displaces BET bromodomains from chromatin by competitively binding to the acetyl lysine recognition pocket. BE(2)-C and Kelly cells were treated in triplicate with 1 µM JQ1 or DMSO for 24 hours. RNA was extracted and a decrease in MYCN transcript was confirmed by real time RT-PCR as described above. The samples were profiled using the Affymetrix PrimeView Human Gene Expression Array (Affymetrix) at Beth Israel Deaconess Medical Center (Boston, MA, USA).
Project description:Signaling through the thrombospondin-1 receptor CD47 broadly limits cell and tissue survival of stress, but the molecular mechanisms are incompletely understood. We now show that loss of CD47 permits sustained proliferation of primary murine endothelial cells and enables these cells to spontaneously reprogram to form multipotent embryoid bodies. c-Myc, Klf4, Oct4, and Sox2 expression is elevated in CD47-null endothelial cells, in several tissues of CD47- or thrombospondin-1-null mice, and in a human T cell line lacking CD47. CD47 knockdown acutely increases mRNA levels of c-Myc and other stem cell transcription factors in cells and in vivo, whereas CD47 ligation by thrombospondin-1 suppresses c-Myc expression. The inhibitory effects of increasing CD47 levels can be overcome by maintaining c-Myc expression and are absent in cells with dysregulated c-Myc. Thus, CD47 antagonists enable cell self-renewal and reprogramming by overcoming negative regulation of c-Myc and other stem cell transcription factors. To identify gene expression changes associated with CD47 null cells, we compared the gene expression profile of these cells with WT endothelial cell, CD47 null Embryoid bodies cells and an established Embryonic Stem cell line.
Project description:p53 executes its diverse functions via different transcriptional targets, but the precise mechanism of promoter-specific regulation by p53 remains largely unknown. Through biochemical purification, we identify PURB, a dual DNA/RNA-binding protein, which acts as a transcriptional co-repressor for p53 in a manner dependent on p53 acetylation status. PURB is overexpressed in human cancers while its knockdown induces p53-dependent activation of p21 but has no effect on other major promoters such as PUMA and Mdm2. In contrast to other p53 corepressors, PURB can recognize a unique DNA element at the p21 promoter, with the loss of this element not affecting p53-mediated transactivation but abrogating the ability of p53 to recruit PURB to the p21 promoter for repression. Mechanistically, PURB requires its sequence-specific binding with lncRNA HOTAIR to exert its repressive role. In turn, HOTAIR interacts directly with EZH2 and, bridged by the PURB/HOTAIR complex, p53 can recruit the EZH2 histone methyltransferase to target promoters for transcriptional repression. Further analysis of p53 targets indicates a number of promoters that may serve as a target for PURB-binding, suggesting that this mechanism of PURB-dependent promoter-specific regulation may not be limited to p21. These data establish a mode of LncRNA-mediated regulation of p53 transcription in a sequence-specific manner and reveal a previously unanticipated mechanism for acetylation-mediated promoter-specific regulation through a cis-regulatory element recognized by the PURB-HOTAIR complex.
Project description:Aortic valve calcification is a significant and serious clinical problem for which there are no effective medical treatments. Individuals born with bicuspid aortic valves, 1-2% of the population, are at the highest risk of developing aortic valve calcification. Aortic valve calcification involves increased levels of calcification and inflammatory genes. Bicuspid aortic valve leaflets experience increased strain. The molecular mechanisms involved in the pathogenesis of calcification of BAVs are not well understood, especially the molecular response to mechanical stretch. HOTAIR is a long non-coding RNA (lncRNA) that has been implicated with cancer but has not been studied in cardiac disease. We have found that HOTAIR levels are decreased in BAVs and in human aortic interstitial cells (AVICs) exposed to cyclic stretch. Reducing HOTAIR levels via siRNA in AVICs results in increased expression of calcification genes.
Project description:Isolated methylmalonic acidemia (MMA) is a pleiotropic enzymatic defect of branched-chain amino acid oxidation most commonly caused by deficiency of methylmalonyl-CoA mutase (MUT). End stage renal disease (ESRD) is emerging as an inevitable disease-related complication, recalcitrant to conventional therapies and liver transplantation. To establish a viable model of MMA-associated renal disease, methylmalonyl-CoA mutase (Mut) was expressed in the liver of Mut -/- mice as a stable transgene under the control of an albumin (INS-Alb-Mut) promoter. Mut -/- ;TgINS-Alb-Mut mice were rescued from the neonatal lethality displayed by Mut -/- mice and manifested a decreased glomerular filtration rate (GFR), chronic tubulointerstital nephritis (CTIN) and prominent ultrastructural changes in the proximal tubular mitochondria, replicating precisely the renal manifestations seen in a large MMA patient cohort. To explore the pathophysiological changes that underlie the renal disease of MMA, we compared gene expression profiles of whole kidney mRNA samples between 4 female Mut +/+, Mut +/- and Mut -/- ;TgINS-Alb-Mut mice after they ingested a HP diet for 2 months. Females were used because more survived the dietary challenge, whereas the histology, ultrastructure and GFR effects were identical between sexes