Project description:Histone H3 lysine-9 methylation (H3K9me) is essential for retinoblastoma protein (RB)-mediated heterochromatin formation, epigenetic silencing of S-phase genes and permanent cell cycle arrest or cellular senescence. Besides as an H3K4me demethylase, lysine-specific demethylase 1 (LSD1) has also been shown to promote H3K9 demethylation. However, it is unclear whether LSD1 plays any roles in regulating cell cycle entry and senescence. Here we demonstrate that genetic depletion or pharmacological inhibition of LSD1 triggers G1 arrest and cellular senescence. Genome-wide chromatin immunoprecipitation-sequencing (ChIP-seq) analysis reveal that the binding sites of LSD1 significantly overlaps with those bound by the S-phase gene transcription factor E2F1. Gene ontology (GO) analysis demonstrates that a large portion of E2F1 and LSD1 co-targeted genes are involved in cell cycle and proliferation. Further analyses show that depletion of LSD1 not only inhibits expression of the LSD1-E2F1 co-target genes, but also decreases the level of H3K9me2, but not H3K4me2 in those loci. Furthermore, the enzymatic activity of LSD1 is essential for H3K9me2 demethylation at cell cycle gene loci. Notably, co-treatment of chemotherapeutic agent camptothecin (CPT) enhanced LSD1 inhibitor-induced senescence and growth inhibition of cancer cells in vitro and in mice. Our data reveal LSD1 as a molecular rheostat regulating selective H3K9 demethylation at cell cycle gene loci, thereby representing a key event in oncogenesis and a viable target for cancer therapy. Overall design: Examination of 2 LSD1 and E2F1 in cell lines
Project description:LSD1 (also known as KDM1A) is a histone demethylase and a key regulator of gene expression in embryonic stem cells and cancer.1,2 LSD1 was initially identified as a transcriptional repressor via its demethylation of active histone H3 marks (di-methyl lysine 4 [2MK4]).1 In prostate cancer, specifically, LSD1 also co-localizes with the AR and demethylates repressive 2MK9 histone marks from androgen-responsive AR target genes, facilitating androgen-mediated induction of AR-regulated gene expression and androgen-induced proliferation in androgen-dependent cancers. We report here that the LSD1 protein is universally upregulated in human CRPC and promotes survival of CRPC cell lines. This effect is explained in part by LSD1-induced activation of cell cycle and embryonic stem cell gene sets—gene sets enriched in transcriptomal studies of lethal human tumors. Importantly, despite the fact that many of these genes are direct LSD1 targets, we did not observe histone methylation changes at the LSD1-bound regions, demonstrating non-canonical histone demethylation-independent mechanisms of gene regulation. This ChIP-seq dataset included H3K4me2 and H3K9me2 ChIP-seq data for siRNA target against LSD1 and non-targeting control, as well as SP2509 inhibition of LSD1 and mock treatment 4 conditions: siRNA against LSD1, siRNA against luciferase (non-targeting control); SP2509 inhibition of LSD1, mock treatment. There are 2 replicates per condition.
Project description:DallePazze2014 - Cellular senescene-induced
This model is described in the article:
Dynamic modelling of
pathways to cellular senescence reveals strategies for targeted
Dalle Pezze P, Nelson G, Otten EG,
Korolchuk VI, Kirkwood TB, von Zglinicki T, Shanley DP.
PLoS Comput. Biol. 2014 Aug; 10(8):
Cellular senescence, a state of irreversible cell cycle
arrest, is thought to help protect an organism from cancer, yet
also contributes to ageing. The changes which occur in
senescence are controlled by networks of multiple signalling
and feedback pathways at the cellular level, and the interplay
between these is difficult to predict and understand. To
unravel the intrinsic challenges of understanding such a highly
networked system, we have taken a systems biology approach to
cellular senescence. We report a detailed analysis of
senescence signalling via DNA damage, insulin-TOR, FoxO3a
transcription factors, oxidative stress response, mitochondrial
regulation and mitophagy. We show in silico and in vitro that
inhibition of reactive oxygen species can prevent loss of
mitochondrial membrane potential, whilst inhibition of mTOR
shows a partial rescue of mitochondrial mass changes during
establishment of senescence. Dual inhibition of ROS and mTOR in
vitro confirmed computational model predictions that it was
possible to further reduce senescence-induced mitochondrial
dysfunction and DNA double-strand breaks. However, these
interventions were unable to abrogate the senescence-induced
mitochondrial dysfunction completely, and we identified
decreased mitochondrial fission as the potential driving force
for increased mitochondrial mass via prevention of mitophagy.
Dynamic sensitivity analysis of the model showed the network
stabilised at a new late state of cellular senescence. This was
characterised by poor network sensitivity, high signalling
noise, low cellular energy, high inflammation and permanent
cell cycle arrest suggesting an unsatisfactory outcome for
treatments aiming to delay or reverse cellular senescence at
late time points. Combinatorial targeted interventions are
therefore possible for intervening in the cellular pathway to
senescence, but in the cases identified here, are only capable
of delaying senescence onset.
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Project description:During brain development, histone-modifying enzymes play an important role by orchestrating transcriptional programs that regulate neuronal maturation. Lysine-Specific Demethylase 1 (LSD1, also named as KDM1A) functions as a transcriptional repressor by removing methyl groups at lysine 4 of histone H3 (H3K4). In neurons, alternative splicing can include an additional exon (exon E8a) within LSD1 transcripts, generating a LSD1+8a neuro-specific isoform. We here report that LSD1+8a isoform does not have the intrinsic ability to demethylate H3K4. LSD1+8a functions as a co-activator on its target genes by removing H3K9 repressive histone marks. We identify the supervillin protein (SVIL) as a LSD1+8a interacting partner and demonstrate that SVIL protein regulates neuronal maturation by controlling LSD1+8a mediated H3K9 demethylation. Thus, our results show that alternative splicing provides a genius mechanism by which LSD1 isoforms can acquire a dual specificity (H3K9 vs H3K4) and therefore differentially control specific gene expression patterns during brain development. Overall design: Examination of 2 different LSD1 isoforms LSD1 and LSD1+8a, LSD1+8a's cofactor SVIL, H3K9me2 in SH-SY5Y cells infected with control or LSD1+8a shRNA during neuronal maturation induced with BNDF at Day0(B0) and Day3(B3).ChIP-seq datas were generated by deep sequencer Hiseq2500.
Project description:Abnormal activities of histone lysine demethylases (KDMs) and lysine deacetylases (HDACs) are associated with aberrant gene expression in breast cancer development. However, the precise molecular mechanisms underlying the crosstalk between KDMs and HDACs in chromatin remodeling and regulation of gene transcription are still elusive. In this study, we showed that treatment of human breast cancer cells with inhibitors targeting the zinc cofactor dependent class I/II HDACs, but not NAD+ dependent class III HDACs, led to significant increase of H3K4me2 which is a specific substrate of histone lysine-specific demethylase 1 (LSD1) and a key chromatin mark promoting transcriptional activation. We also demonstrated that inhibition of LSD1 activity by a pharmacological inhibitor, pargyline, or siRNA resulted in increased acetylation of H3K9 (AcH3K9). However, siRNA knockdown of LSD2, a homolog of LSD1, failed to alter the level of AcH3K9, suggesting that LSD2 activity may not be functionally connected with HDAC activity. Combined treatment with LSD1 and HDAC inhibitors resulted in enhanced levels of H3K4me2 and AcH3K9, and exhibited synergistic growth inhibition of breast cancer cells. Finally, microarray screening identified a unique subset of genes whose expression was significantly changed by combination treatment with inhibitors of LSD1 and HDAC. Our study suggests that LSD1 intimately interacts with histone deacetylases in human breast cancer cells. Inhibition of histone demethylation and deacetylation exhibits cooperation and synergy in regulating gene expression and growth inhibition, and may represent a promising and novel approach for epigenetic therapy of breast cancer. Twelve samples were subject to microarray anaylsis: 3 biological replicates were treated for 24h with 1)DMSO, 2) 5uM SAHA (suberanilohydroxamic acid), 3) 2.5mM Pargyline or 4) 5uM SAHA + 2.5mM Pargyline.
Project description:During brain development, histone-modifying enzymes play an important role by orchestrating transcriptional programs that regulate neuronal maturation. Lysine-Specific Demethylase 1 (LSD1, also named as KDM1A) functions as a transcriptional repressor by removing methyl groups at lysine 4 of histone H3 (H3K4). In neurons, alternative splicing can include an additional exon (exon E8a) within LSD1 transcripts, generating a LSD1+8a neuro-specific isoform. We here report that LSD1+8a isoform does not have the intrinsic ability to demethylate H3K4. LSD1+8a functions as a co-activator on its target genes by removing H3K9 repressive histone marks. We identify the supervillin protein (SVIL) as a LSD1+8a interacting partner and demonstrate that SVIL protein regulates neuronal maturation by controlling LSD1+8a mediated H3K9 demethylation. Thus, our results show that alternative splicing provides a genius mechanism by which LSD1 isoforms can acquire a dual specificity (H3K9 vs H3K4) and therefore differentially control specific gene expression patterns during brain development. In order to find some LSD1+8a regulated genes at differentiated SH-SY5Y cell lines, we infected SH-SY5Y with control or LSD1+8a shRNA, then induced differentiation with RA and BDNF, (Retinoic acid (RA) (Sigma) was added at a final concentration of 10 μM the next day after plating. After 4 days, the cells were washed three times with PBS and incubated with 50 ng/mL of Brain Derived Neural Factor (BDNF) (Millipore) in serum-free medium for 3 days), we extracted RNA from BDNF induced SH-SY5Y cells for expression analysis.Duplicates were included for Affymetrix Human transcriptome version 2 array.
Project description:By screening a collection of epigenetic compounds, we find that Lysine-Specific Demethylase 1 (LSD1) inhibitors repress brown adipocyte differentiation. RNAi-mediated Lsd1 knockdown shows similar effect, which can be rescued by expression of wild-type, but not catalytically inactive, LSD1. Furthermore, adenoviral Cre-mediated LSD1 deletion in mice leads to inhibition of brown adipogenesis, validating the pivotal role of LSD1 in brown fat development in vivo. LSD1 is a histone H3 demethylase, which selectively removes methyl groups from mono- and di-methylated lysine 4 (H3K4me1 and H3K4me2) under most circumstances, and only from lysine 9 (H3K9me1/2) when bound with androgen receptor (AR) or estrogen receptor (ER). K4 demethylation causes transcription repression, while K9 demethylation may lead to activation of gene transcription. To investigate the target genes of LSD1 during BAT differentiaiton, we performed RNA-seq to profile the gene expression in brown adipocytes treated with DMSO or LSD1 inhibitor 611 (Cpd A) for 6 days, and gene set enrichment analysis (GSEA) was then employed to identify Gene Ontology (GO) terms that were significantly enriched. Overall design: RNA-Seq data for brown adipocytes treated with DMSO or LSD1 inhibitor 611 (Cpd A). Biological triplicates were performed for each group.
Project description:Lysine Specific Demethylase 1 (LSD1, KDM1A) functions as a transcriptional corepressor through demethylation of histone 3 lysine 4 (H3K4), but has coactivator function on some genes through unclear mechanisms. We show that LSD1, interacting with CoREST, associates with and coactivates androgen receptor (AR) on a large fraction of androgen-stimulated genes. A subset of these AR/LSD1-associated enhancer sites have histone 3 threonine 6 phosphorylation (H3T6ph), and these sites are further enriched for androgen-stimulated genes. Significantly, despite its coactivator activity, LSD1 still mediates H3K4me2 demethylation at these androgen-stimulated enhancers. FOXA1 is also associated with LSD1 at AR regulated enhancer sites, and a FOXA1 interaction with LSD1 enhances binding of both proteins at these sites. These findings show LSD1 functions broadly as a regulator of AR function, that it maintains a transcriptional repression function at AR-regulated enhancers through H3K4 demethylation, and has a distinct AR-linked coactivator function mediated by demethylation of other substrates. Determine the role of LSD1 in androgen signaling.
Project description:LSD1 (also known as KDM1A) is a histone demethylase and a key regulator of gene expression in embryonic stem cells and cancer.1,2 LSD1 was initially identified as a transcriptional repressor via its demethylation of active histone H3 marks (di-methyl lysine 4 [2MK4]).1 In prostate cancer, specifically, LSD1 also co-localizes with the AR and demethylates repressive 2MK9 histone marks from androgen-responsive AR target genes, facilitating androgen-mediated induction of AR-regulated gene expression and androgen-induced proliferation in androgen-dependent cancers.3,4 Recently, it was shown that treatment with high doses of androgens (e.g.10-fold higher doses than those required for induction of expression of androgen-activated genes such as PSA) recruits LSD1 and AR to an enhancer within the AR; this AR and LSD1 recruitment represses AR transcription.5 Thus, LSD1 appears to play a role in mediating both the proliferative and repressive phases of the biphasic androgen dose-response curve. For these reasons, we hypothesized that LSD1 might be important for maintenance of AR signaling in castration-resistant prostate cancer (CRPC) tumors. However, in this report, we describe a distinct role of LSD1 as a driver of proliferation and survival of prostate cancer cells, including CRPC cells, irrespective of androgens or even AR expression. Specifically, LSD1 activates expression of cell cycle, mitosis, and embryonic stem cell maintenance pathways that are enriched in lethal prostate cancers – pathways not activated by androgens. Finally, we observe that treatment with a new LSD1 inhibitor potently and specifically suppresses LSD1 function and suppresses CRPC growth and survival in vitro and in vivo. Our data place LSD1 as a key driver of androgen-independent survival in lethal prostate cancers and demonstrate the potential of LSD1-directed therapies in the near-term. The enclosed files are from microarrays experiments after suppressing LSD1 with RNAi or stimulating cells with the androgen agonist dihydrotestosterone (DHT).