Genome-wide analysis of gene expression by LSD1 overexpression or inhibiting by ORY1001 with or without irradiation in MDA-MB-231 breast cancer cells
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ABSTRACT: Analysis of LSD1 regulation after DNA damage at gene expression level.We supposed that LSD1 is involved in Double Strand DNA repair, alterated LSD1 expression with transfection vector or LSD1 inhibtor in MDA-MB-231, and finally found LSD1 promted DNA damage reponse after IR treatment.
Project description:Heterochromatin is a specialized form of chromatin that restricts access to DNA and inhibits genetic processes, including transcription and recombination. In Neurospora crassa, constitutive heterochromatin is characterized by trimethylation of lysine 9 on histone H3, hypoacetylation of histones, and DNA methylation. Here we explore whether the conserved histone demethylase, lysine-specific demethylase 1 (LSD1), regulates heterochromatin in Neurospora, and if so, how. Though LSD1 is implicated in heterochromatin regulation, its function is inconsistent across different systems; orthologs of LSD1 have been shown to either promote or antagonize heterochromatin expansion by removing H3K4me or H3K9me respectively. We identify three members of the Neurospora LSD complex (LSDC): LSD1, PHF1, and BDP-1, and strains deficient for any exhibit variable spreading of heterochromatin and establishment of new heterochromatin domains dispersed across the genome. Heterochromatin establishment outside of canonical domains in Neurospora share the unusual characteristic of DNA methylation-dependent H3K9me3; typically, H3K9me3 establishment is independent of DNA methylation. Consistent with this, the hyper-H3K9me3 phenotype of LSD1 knock-out strains is dependent on the presence of DNA methylation, as well as HCHC-mediated histone deacetylation, suggesting spreading is dependent on some feedback mechanism. Altogether, our results suggest LSD1 works in opposition to HCHC to maintain proper heterochromatin boundaries.
Project description:The purpose of this study was to define biomarkers of sensitivty and mechanisms of resistance to the KDM1A/LSD1 inhibtor SP-2509 (HCI-2509) in Ewing sarcoma cell lines. We report that regardless of drug sensitivity all cell lines engage the UPR and ER-stress response following treatment with SP-2509 resulting in apoptotic cytotoxicity. In addition hypersentsitive cell lines shared a common basal transcriptnomic profile, with hypersensitive cell lines signficantly inducing ETS1 which was not observed in sensitive cell lines.
Project description:Cockayne syndrome (CS) is mainly caused by mutations in CSB gene encoding a protein belonging to SWI/SNF chromatin remodeling family. CS1AN cells derived from CS patients carrying mutations in CSB gene are useful for the study of nucleotide excision repair (NER) upon UV- or oxidative stress-induced DNA damage. However, establishment of isogenic cells endogenously expressing wild type CSB is tedious and difficult. Normal fibroblast MRC5 has been widely used to study cellular reponse to stress. This study was designed to systematically analyze the features of these two cell lines during DNA damage and repair pathways, aiming to provide a reference for application of these two cell lines as in vitro model. We show that CS1AN is hypersensitive to UV irradiation compared to MRC5. We found that CSB is essential for regulating gene expression in response to DNA damage.
Project description:We report the identification of LSD1 binding genomic regions in mouse embryonic stem cells (ESC) by high throughput sequencing. By obtaining over 10 million 36 bp reads of sequence from each chromatin immunoprecipitated DNA, we generated genome-wide maps for LSD1 and histone H3 dimethylated on lysine 4 (H3K4me2), the substrate for LSD1 in mouse ESCs. Our results showed an extensive overlap between the LSD1 and H3K4me2 genomic regions and a correlation between the genomic levels of LSD1/H3K4me2 and gene expression, including many highly expressed ESC genes. LSD1 is recruited to the chromatin of cells in the G1/S/G2 phases and is displaced from the chromatin of M phase cells, suggesting that LSD1 or H3K4me2 alternatively occupies LSD1 genomic regions during cell cycle progression. LSD1 knockdown by RNA interference or its displacement from the chromatin by anti-neoplastic agents caused an increase in the levels of a subset of LSD1 target genes. Taken together, these results suggest that cell-cycle dependent association and dissociation of LSD1 with chromatin mediates short-time scale gene expression changes during ES cell cycle progression. Examination of LSD1 and lysine 4 dimethylated histone H3 (H3K4me2) binding genomic regions in embryonic stem cells. Input genomic DNA and DNA immunoprecipitaed with control IgG was included as controls.
Project description:Lsd1 ablation triggers metabolic reprogramming of brown adipose tissue. Lsd1 protein complexes were purified from mouse adipose tissue and analyzed by label-free LC-MS/MS. Mice were kept under different conditions prior complex isolation.
Project description:Merkel cell carcinoma (MCC) is an aggressive neuroendocrine cancer of the skin, caused by either excessive UV damage or integration of the Merkel cell polyomavirus (MCV) genome. Here, we report that virally encoded MCV small T antigen (ST) establishes dependence on the LSD1 transcriptional repressor. Inhibition of LSD1 reduces growth of MCV-positive MCC and suppresses ST’s transformation capacity in vitro and in vivo. To define the mechanism of LSD1 inhibition in MCC, we performed a CRISPR loss-of-function library screen. We found that deletion of components of the non-canonical (ncBAF) chromatin remodeler complex confers resistance to LSD1 inhibitors and that LSD1 and ncBAF antagonistically regulate an overlapping set of genes involved in neuron differentiation. Our work provides mechanistic insight into the dependence of MCC on LSD1 and the role of ncBAF as a tumor suppressor in cancer.
Project description:Tumor-initiating cells (TICs) play a critical role in glioblastoma (GBM) maintenance being responsible for its heterogeneity and resistance to standard therapy. A step toward clinical translation includes GBM TIC targeting. Among the molecules tested for GBM treatment, are those targeting epigenetic modifiers. By using patient-derived TICs and xenograft orthotopic models, we identified Lysine-specific histone demethylase 1A (LSD1) as a potentially druggable target in GBM. LSD1-directed therapy by means of the selective, orally bioavailable and brain penetrant inhibitor DDP_38003 effectively impairs growth, stem-like features and tumorigenic potential of GBM TICs. Our findings point to LSD1 as a positive regulator of Activating Transcription Factor 4 (ATF4)-dependent response in all stress conditions arising during tumor growth and therapy. Thus, through the downregulation of either ATF4 and its adaptive genes, LSD1 targeting is likely a promising strategy to hit GBM TICs by counteracting the ATF4-mediated adaptation to stress.
Project description:Merkel cell carcinoma (MCC) is an aggressive neuroendocrine cancer of the skin, caused by either excessive UV damage or integration of the Merkel cell polyomavirus (MCV) genome. Here, we report that virally encoded MCV small T antigen (ST) establishes dependence on the LSD1 transcriptional repressor. Inhibition of LSD1 reduces growth of MCV-positive MCC and suppresses ST’s transformation capacity in vitro and in vivo. To define the mechanism of LSD1 inhibition in MCC, we performed a CRISPR loss-of-function library screen. We found that deletion of components of the non-canonical (ncBAF) chromatin remodeler complex confers resistance to LSD1 inhibitors and that LSD1 and ncBAF antagonistically regulate an overlapping set of genes involved in neuron differentiation. Our work provides mechanistic insight into the dependence of MCC on LSD1 and the role of ncBAF as a tumor suppressor in cancer.
Project description:The chromatin-based rules governing the selection and activation of replication origins remain to be elucidated. It is believed that DNA replication initiates from open chromatin domains, thus replication origins residing in regulatory elements that are located at open and active chromatin. However, we report here that lysine specific demethylase 1 (LSD1), which biochemically catalyzes H3K4me1/2 demethylation to favor chromatin condensation, interacts with the DNA replication machinery. We found that LSD1 level peaks in early S phase. We demonstrated that LSD1 promotes DNA replication by facilitating origin firing in euchromatic regions and through regulating replication timing. Indeed, euchromatic zones enriched in H3K4me2 are the preferred sites for pre-RC binding in early replication. Remarkably, LSD1 deficiency leads to a genome-wide switch from early to late in replication timing. We showed that LSD1-promoted DNA replication is mechanistically linked to the loading of TICRR (TopBP1-Interacting Checkpoint and Replication Regulator) onto the pre-RC and subsequent recruitment of the initiator Cdc45 during origin firing. Together, these results reveal an unexpected role for LSD1 in euchromatic origin firing and replication timing.
Project description:The chromatin-based rules governing the selection and activation of replication origins remain to be elucidated. It is believed that DNA replication initiates from open chromatin domains, thus replication origins residing in regulatory elements that are located at open and active chromatin. However, we report here that lysine specific demethylase 1 (LSD1), which biochemically catalyzes H3K4me1/2 demethylation to favor chromatin condensation, interacts with the DNA replication machinery. We found that LSD1 level peaks in early S phase. We demonstrated that LSD1 promotes DNA replication by facilitating origin firing in euchromatic regions and through regulating replication timing. Indeed, euchromatic zones enriched in H3K4me2 are the preferred sites for pre-RC binding in early replication. Remarkably, LSD1 deficiency leads to a genome-wide switch from early to late in replication timing. We showed that LSD1-promoted DNA replication is mechanistically linked to the loading of TICRR (TopBP1-Interacting Checkpoint and Replication Regulator) onto the pre-RC and subsequent recruitment of the initiator Cdc45 during origin firing. Together, these results reveal an unexpected role for LSD1 in euchromatic origin firing and replication timing.