RESUMO
Treatment of prostate cancer relies predominantly on the inhibition of androgen receptor (AR) signaling. Despite the initial effectiveness of the antiandrogen therapies, the cancer often develops resistance to the AR blockade. One mechanism of the resistance is glucocorticoid receptor (GR)-mediated replacement of AR function. Nevertheless, the mechanistic ways and means how the GR-mediated antiandrogen resistance occurs have remained elusive. Here, we have discovered several crucial features of GR action in prostate cancer cells through genome-wide techniques. We detected that the replacement of AR by GR in enzalutamide-exposed prostate cancer cells occurs almost exclusively at pre-accessible chromatin sites displaying FOXA1 occupancy. Counterintuitively to the classical pioneer factor model, silencing of FOXA1 potentiated the chromatin binding and transcriptional activity of GR. This was attributed to FOXA1-mediated repression of the NR3C1 (gene encoding GR) expression via the corepressor TLE3. Moreover, the small-molecule inhibition of coactivator p300's enzymatic activity efficiently restricted GR-mediated gene regulation and cell proliferation. Overall, we identified chromatin pre-accessibility and FOXA1-mediated repression as important regulators of GR action in prostate cancer, pointing out new avenues to oppose steroid receptor-mediated antiandrogen resistance.
Assuntos
Cromatina , Neoplasias da Próstata , Receptores de Glucocorticoides , Humanos , Masculino , Antagonistas de Androgênios/farmacologia , Linhagem Celular Tumoral , Cromatina/genética , Regulação Neoplásica da Expressão Gênica , Fator 3-alfa Nuclear de Hepatócito/genética , Fator 3-alfa Nuclear de Hepatócito/metabolismo , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Receptores Androgênicos/genética , Receptores Androgênicos/metabolismo , Receptores de Glucocorticoides/genética , Receptores de Glucocorticoides/metabolismoRESUMO
The androgen receptor (AR) is pivotal in prostate cancer (PCa) progression and represents a critical therapeutic target. AR-mediated gene regulation involves intricate interactions with nuclear proteins, with many mediating and undergoing post-translational modifications that present alternative therapeutic avenues. Through chromatin proteomics in PCa cells, we identified SUMO ligases together with nuclear receptor coregulators and pioneer transcription factors within the AR's protein network. Intriguingly, this network displayed a significant association with SUMO2/3. To elucidate the influence of SUMOylation on AR chromatin interactions and subsequent gene regulation, we inhibited SUMOylation using ML-792 (SUMOi). While androgens generally facilitated the co-occupancy of SUMO2/3 and AR on chromatin, SUMOi induced divergent effects dependent on the type of AR-binding site (ARB). SUMOi augmented AR's pioneer-like binding on inaccessible chromatin regions abundant in androgen response elements (AREs) and diminished its interaction with accessible chromatin regions sparse in AREs yet rich in pioneer transcription factor motifs. The SUMOi-impacted ARBs divergently influenced AR-regulated genes; those associated with AR-mediated activation played roles in negative regulation of cell proliferation, while those with AR-mediated repression were involved in pattern formation. In conclusion, our findings underscore the pervasive influence of SUMOylation in shaping AR's role in PCa cells, potentially unveiling new therapeutic strategies.
RESUMO
Autonomous parvoviruses encode at least two nonstructural proteins, NS1 and NS2. While NS1 is linked to important nuclear processes required for viral replication, much less is known about the role of NS2. Specifically, the function of canine parvovirus (CPV) NS2 has remained undefined. Here we have used proximity-dependent biotin identification (BioID) to screen for nuclear proteins that associate with CPV NS2. Many of these associations were seen both in noninfected and infected cells, however, the major type of interacting proteins shifted from nuclear envelope proteins to chromatin-associated proteins in infected cells. BioID interactions revealed a potential role for NS2 in DNA remodeling and damage response. Studies of mutant viral genomes with truncated forms of the NS2 protein suggested a change in host chromatin accessibility. Moreover, further studies with NS2 mutants indicated that NS2 performs functions that affect the quantity and distribution of proteins linked to DNA damage response. Notably, mutation in the splice donor site of the NS2 led to a preferred formation of small viral replication center foci instead of the large coalescent centers seen in wild-type infection. Collectively, our results provide insights into potential roles of CPV NS2 in controlling chromatin remodeling and DNA damage response during parvoviral replication.
Assuntos
Infecções por Parvoviridae , Parvovirus , Linhagem Celular , Cromatina , Humanos , Parvovirus/genética , Proteínas não Estruturais Virais/genética , Proteínas não Estruturais Virais/metabolismo , Replicação ViralRESUMO
Glucocorticoid receptor (GR) is an essential transcription factor (TF), controlling metabolism, development and immune responses. SUMOylation regulates chromatin occupancy and target gene expression of GR in a locus-selective manner, but the mechanism of regulation has remained elusive. Here, we identify the protein network around chromatin-bound GR by using selective isolation of chromatin-associated proteins and show that the network is affected by receptor SUMOylation, with several nuclear receptor coregulators and chromatin modifiers preferring interaction with SUMOylation-deficient GR and proteins implicated in transcriptional repression preferring interaction with SUMOylation-competent GR. This difference is reflected in our chromatin binding, chromatin accessibility and gene expression data, showing that the SUMOylation-deficient GR is more potent in binding and opening chromatin at glucocorticoid-regulated enhancers and inducing expression of target loci. Blockage of SUMOylation by a SUMO-activating enzyme inhibitor (ML-792) phenocopied to a large extent the consequences of GR SUMOylation deficiency on chromatin binding and target gene expression. Our results thus show that SUMOylation modulates the specificity of GR by regulating its chromatin protein network and accessibility at GR-bound enhancers. We speculate that many other SUMOylated TFs utilize a similar regulatory mechanism.
Assuntos
Cromatina/metabolismo , Receptores de Glucocorticoides/metabolismo , Sumoilação , Sítios de Ligação , Regulação da Expressão Gênica , Células HEK293 , Humanos , Correpressor 1 de Receptor Nuclear/metabolismo , Coativador 1 de Receptor Nuclear , Mapeamento de Interação de Proteínas , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/metabolismo , Sumoilação/efeitos dos fármacosRESUMO
Post-translational modifications, e.g. SUMO modifications (SUMOylation), provide a mechanism for swiftly changing a protein's activity. Various stress conditions trigger a SUMO stress response (SSR) - a stress-induced rapid change in the conjugation of SUMO to multiple proteins, which predominantly targets nuclear proteins. The SSR has been postulated to protect stressed cells by preserving the functionality of crucial proteins. However, it is unclear how it exerts its protective functions. Interestingly, heat stress (HS) increases SUMOylation of proteins at active promoters and enhancers. In promoters, HS-induced SUMOylation correlates with gene transcription and stress-induced RNA polymerase II (Pol2) pausing. Conversely, a disappearance of SUMOylation in HS occurs at chromatin anchor points that maintain chromatin-looping structures and the spatial organisation of chromatin. In reviewing the literature, we hypothesise that the SSR regulates Pol2 pausing by modulating the interactions of pausing-regulating proteins, whereas deSUMOylation alters the function of chromatin anchors.
Assuntos
Cromatina/metabolismo , Resposta ao Choque Térmico , Proteínas Nucleares/metabolismo , Sumoilação , Animais , Cromatina/fisiologia , Humanos , RNA Polimerase II/metabolismo , Sequências Reguladoras de Ácido NucleicoRESUMO
Glucocorticoid receptor (GR) and androgen receptor (AR) are steroid-inducible transcription factors (TFs). The GR and the AR are central regulators of various metabolic, homeostatic and differentiation processes and hence important therapeutic targets, especially in inflammation and prostate cancer, respectively. Hormone binding to these steroid receptors (SRs) leads to DNA binding and activation or repression of their target genes with the aid of interacting proteins, coregulators. However, protein interactomes of these important drug targets have remained poorly defined. We used proximity-dependent biotin identification to map the protein interaction landscapes of GR and AR in the presence and absence of their cognate agonist (dexamethasone, 5α-dihydrotestosterone) and antagonist (RU486, enzalutamide) in intact human cells. We reproducibly identified more than 30 proteins that interacted with the GR in an agonist-specific manner and whose interactions were significantly influenced by the DNA-binding function of the receptor. Interestingly, the agonist-dependent interactome of the GR overlapped considerably with that of the AR. In addition to known coactivators, corepressors and components of BAF (SWI/SNF) chromatin-remodeling complex, we identified a number of proteins, including lysine methyltransferases and demethylases that have not been previously linked to glucocorticoid or androgen signaling. A substantial number of these novel agonist-dependent GR/AR-interacting proteins, e.g. BCOR, IRF2BP2, RCOR1, and TLE3, have previously been implicated in transcription repression. This together with our data on the effect of BCOR, IRF2BP2, and RCOR1 on GR target gene expression suggests multifaceted functions and roles for SR coregulators. These first high confidence SR interactomes will aid in therapeutic targeting of the GR and the AR.
Assuntos
Mapeamento de Interação de Proteínas , Receptores Androgênicos/metabolismo , Receptores de Glucocorticoides/antagonistas & inibidores , Receptores de Glucocorticoides/metabolismo , Células A549 , Benzamidas , Proteínas Correpressoras/metabolismo , Proteínas de Ligação a DNA/metabolismo , Dexametasona/farmacologia , Di-Hidrotestosterona/farmacologia , Humanos , Masculino , Mifepristona/farmacologia , Nitrilas , Proteínas Nucleares/metabolismo , Feniltioidantoína/análogos & derivados , Feniltioidantoína/farmacologia , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Receptores Androgênicos/genética , Receptores de Glucocorticoides/agonistas , Receptores de Glucocorticoides/genética , Transcrição GênicaRESUMO
Inflammatory processes and androgen signaling are critical for the growth of prostate cancer (PC), the most common cancer among males in Western countries. To understand the importance of potential interplay between pro-inflammatory and androgen signaling for gene regulation, we have interrogated the crosstalk between androgen receptor (AR) and NF-κB, a key transcriptional mediator of inflammatory responses, by utilizing genome-wide chromatin immunoprecipitation sequencing and global run-on sequencing in PC cells. Co-stimulation of LNCaP cells with androgen and pro-inflammatory cytokine TNFα invoked a transcriptome which was very distinct from that induced by either stimulation alone. The altered transcriptome that included gene programs linked to cell migration and invasiveness was orchestrated by significant remodeling of NF-κB and AR cistrome and enhancer landscape. Although androgen multiplied the NF-κB cistrome and TNFα restrained the AR cistrome, there was no general reciprocal tethering of the AR to the NF-κB on chromatin. Instead, redistribution of FOXA1, PIAS1 and PIAS2 contributed to the exposure of latent NF-κB chromatin-binding sites and masking of AR chromatin-binding sites. Taken together, concomitant androgen and pro-inflammatory signaling significantly remodels especially the NF-κB cistrome, reprogramming the PC cell transcriptome in fashion that may contribute to the progression of PC.
Assuntos
Androgênios/metabolismo , Regulação Neoplásica da Expressão Gênica , Mediadores da Inflamação/metabolismo , NF-kappa B/metabolismo , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Receptores Androgênicos/metabolismo , Transcriptoma , Linhagem Celular Tumoral , Cromatina/genética , Cromatina/metabolismo , Análise por Conglomerados , Citocinas/metabolismo , Elementos Facilitadores Genéticos , Perfilação da Expressão Gênica , Fator 3-alfa Nuclear de Hepatócito/metabolismo , Humanos , Masculino , Proteínas Inibidoras de STAT Ativados/metabolismoRESUMO
UNLABELLED: The association of host histones with parvoviral DNA is poorly understood. We analyzed the chromatinization and histone acetylation of canine parvovirus DNA during infection by confocal imaging andin situproximity ligation assay combined with chromatin immunoprecipitation and high-throughput sequencing. We found that during late infection, parvovirus replication bodies were rich in histones bearing modifications characteristic of transcriptionally active chromatin, i.e., histone H3 lysine 27 acetylation (H3K27ac). H3K27ac, in particular, was located in close proximity to the viral DNA-binding protein NS1. Importantly, our results show for the first time that in the chromatinized parvoviral genome, the two viral promoters in particular were rich in H3K27ac. Histone acetyltransferase (HAT) inhibitors efficiently interfered with the expression of viral proteins and infection progress. Altogether, our data suggest that the acetylation of histones on parvoviral DNA is essential for viral gene expression and the completion of the viral life cycle. IMPORTANCE: Viral DNA introduced into cell nuclei is exposed to cellular responses to foreign DNA, including chromatinization and epigenetic silencing, both of which determine the outcome of infection. How the incoming parvovirus resists cellular epigenetic downregulation of its genes is not understood. Here, the critical role of epigenetic modifications in the regulation of parvovirus infection was demonstrated. We showed for the first time that a successful parvovirus infection is characterized by the deposition of nucleosomes with active histone acetylation on the viral promoter areas. The results provide new insights into the regulation of parvoviral gene expression, which is an important aspect of the development of parvovirus-based virotherapy.
Assuntos
Cromatina/virologia , Genoma Viral , Histonas/metabolismo , Infecções por Parvoviridae/virologia , Parvovirus Canino/genética , Regiões Promotoras Genéticas , Acetilação , Animais , Gatos , Linhagem Celular , DNA Viral/metabolismo , Epigênese Genética , Regulação Viral da Expressão Gênica , Lisina/metabolismo , Microscopia Confocal , Parvovirus Canino/metabolismo , Integração ViralRESUMO
Canine parvovirus (CPV) infection induces reorganization of nuclear structures. Our studies indicated that late-stage infection induces accumulation of nuclear pore complexes (NPCs) and lamin B1 concomitantly with a decrease of lamin A/C levels on the apical side of the nucleus. Newly formed CPV capsids are located in close proximity to NPCs on the apical side. These results suggest that parvoviruses cause apical enrichment of NPCs and reorganization of nuclear lamina, presumably to facilitate the late-stage infection.
Assuntos
Doenças do Cão/virologia , Lamina Tipo B/metabolismo , Complexo de Proteínas Formadoras de Poros Nucleares/metabolismo , Poro Nuclear/metabolismo , Infecções por Parvoviridae/virologia , Parvovirus Canino/metabolismo , Animais , Capsídeo/metabolismo , Núcleo Celular/metabolismo , Cães , Lamina Tipo A/metabolismo , Lâmina Nuclear/metabolismoRESUMO
The multifunctional replication protein of autonomous parvoviruses, NS1, is vital for viral genome replication and for the control of viral protein production. Two DNA-interacting domains of NS1, the N-terminal and helicase domains, are necessary for these functions. In addition, the N and C termini of NS1 are required for activation of viral promoter P38. By comparison with the structural and biochemical data from other parvoviruses, we identified potential DNA-interacting amino acid residues from canine parvovirus NS1. The role of the identified amino acids in NS1 binding dynamics was studied by mutagenesis, fluorescence recovery after photobleaching, and computer simulations. Mutations in the predicted DNA-interacting amino acids of the N-terminal and helicase domains increased the intranuclear binding dynamics of NS1 dramatically. A substantial increase in binding dynamics was also observed for NS1 mutants that targeted the metal ion coordination site in the N terminus. Interestingly, contrary to other mutants, deletion of the C terminus resulted in slower binding dynamics of NS1. P38 transactivation was severely reduced in both N-terminal DNA recognition and in C-terminal deletion mutants. These data suggest that the intranuclear dynamics of NS1 are largely characterized by its sequence-specific and -nonspecific binding to double-stranded DNA. Moreover, binding of NS1 is equally dependent on the N-terminal domain and conserved ß-loop of the helicase domain.
Assuntos
Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Mutação de Sentido Incorreto , Parvovirus Canino/fisiologia , Proteínas não Estruturais Virais/genética , Proteínas não Estruturais Virais/metabolismo , Replicação Viral , Animais , Linhagem Celular , DNA/metabolismo , Análise Mutacional de DNA , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Ligação Proteica , Estrutura Terciária de ProteínaRESUMO
The inflammatory tumor microenvironment (TME) is a key driver for tumor-promoting processes. Tumor-associated macrophages are one of the main immune cell types in the TME and their increased density is related to poor prognosis in prostate cancer. Here, we investigated the influence of pro-inflammatory (M1) and immunosuppressive (M2) macrophages on prostate cancer lineage plasticity. Our findings reveal that M1 macrophage secreted factors upregulate genes related to stemness while downregulating genes associated with androgen response in prostate cancer cells. The expression of cancer stem cell (CSC) plasticity markers NANOG, KLF4, SOX2, OCT4, and CD44 was stimulated by the secreted factors from M1 macrophages. Moreover, AR and its target gene PSA were observed to be suppressed in LNCaP cells treated with secreted factors from M1 macrophages. Inhibition of NFκB signaling using the IKK16 inhibitor resulted in downregulation of NANOG, SOX2, and CD44 and CSC plasticity. Our study highlights that the secreted factors from M1 macrophages drive prostate cancer cell plasticity by upregulating the expression of CSC plasticity markers through NFκB signaling pathway.
Assuntos
Receptores de Hialuronatos , Fator 4 Semelhante a Kruppel , Macrófagos , NF-kappa B , Proteína Homeobox Nanog , Células-Tronco Neoplásicas , Neoplasias da Próstata , Fatores de Transcrição SOXB1 , Transdução de Sinais , Masculino , Humanos , Neoplasias da Próstata/patologia , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/genética , Proteína Homeobox Nanog/metabolismo , Proteína Homeobox Nanog/genética , Fatores de Transcrição SOXB1/metabolismo , Fatores de Transcrição SOXB1/genética , Receptores de Hialuronatos/metabolismo , Receptores de Hialuronatos/genética , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Fator 4 Semelhante a Kruppel/metabolismo , NF-kappa B/metabolismo , Linhagem Celular Tumoral , Macrófagos/metabolismo , Regulação para Cima , Microambiente Tumoral/imunologia , Plasticidade Celular/genética , Regulação Neoplásica da Expressão Gênica , Macrófagos Associados a Tumor/metabolismo , Macrófagos Associados a Tumor/imunologia , Animais , CamundongosRESUMO
Canine parvovirus (CPV) infection leads to reorganization of nuclear proteinaceous subcompartments. Our studies showed that virus infection causes a time-dependent increase in the amount of viral nonstructural protein NS1 mRNA. Fluorescence recovery after photobleaching showed that the recovery kinetics of nuclear transcription-associated proteins, TATA binding protein (TBP), transcription factor IIB (TFIIB), and poly(A) binding protein nuclear 1 (PABPN1) were different in infected and noninfected cells, pointing to virus-induced alterations in binding dynamics of these proteins.
Assuntos
Infecções por Parvoviridae/metabolismo , Frações Subcelulares/metabolismo , Fatores de Transcrição/metabolismo , Animais , Compartimento Celular , Parvovirus Canino/isolamento & purificaçãoRESUMO
BACKGROUND: Accumulating evidence indicates importance of RNA regulation in cancer. This includes events such as splicing, translation, and regulation of noncoding RNAs, functions which are governed by RNA binding proteins (RBPs). AIMS: To find which RBPs could be relevant for prostate cancer, we performed systematic screening of RBP expression in clinical prostate cancer. METHODS AND RESULTS: We interrogated four proteome-wide proteomics datasets including tumor samples of primary, castration resistant, and metastatic prostate cancer. We found that, while the majority of RBPs are expressed but not significantly altered during prostate cancer development and progression, expression of several RBPs increases in advanced disease. Interestingly, most of the differentially expressed RBPs are not targets of differential posttranscriptional phosphorylation during disease progression. The RBPs undergoing expression changes have functions in, especially, poly(A)-RNA binding, nucleocytoplasmic transport, and cellular stress responses, suggesting that these may play a role in formation of castration resistance. Pathway analyzes indicate that increased ribosome production and chromatin-related functions of RBPs are also linked to castration resistant and metastatic prostate cancers. We selected a group of differentially expressed RBPs and studied their role in cultured prostate cancer cells. With siRNA screens, several of these were indicated in survival (DDX6, EIF4A3, PABPN1), growth (e.g., EIF5A, HNRNPH2, LRRC47, and NVL), and migration (e.g., NOL3 and SLTM) of prostate cancer cells. Our analyzes further show that RRP9, a U3 small nucleolar protein essential for ribosome formation, undergoes changes at protein level during metastasis in prostate cancer. CONCLUSION: In this work, we recognized significant molecular alterations in RBP profiles during development and evolution of prostate cancer. Our study further indicates several functionally significant RBPs warranting further investigation for their functions and possible targetability in prostate cancer.
Assuntos
Neoplasias da Próstata , Proteoma , Masculino , Humanos , Proteoma/metabolismo , Proteômica , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Neoplasias da Próstata/genética , RNA Interferente Pequeno , Fator de Iniciação 4A em Eucariotos/metabolismo , RNA Helicases DEAD-box/metabolismo , Proteína I de Ligação a Poli(A)RESUMO
Virus-induced alterations in cell morphology play important roles in the viral life cycle. To examine the intracellular events of coxsackievirus B3 (CVB3) infection, green monkey kidney (GMK) cells were either inoculated with the virus or transfected with the viral RNA. Various microscopic and flow cytometric approaches demonstrated the emergence of CVB3 capsid proteins at 8 h posttransfection, followed by morphological transformation of the cells. The morphological changes included formation of membranous protrusions containing viral capsids, together with microtubules and actin. Translocation of viral capsids into these protrusions was sensitive to cytochalasin D, suggesting the importance of actin in the process. Three-dimensional (3D) live-cell imaging demonstrated frequent contacts between cellular protrusions and adjacent cells. Markedly, in spite of an increase in the cellular viral protein content starting 8 h postinfection, no significant decrease in cell viability or increase in the amount of early apoptotic markers was observed by flow cytometry by 28 h postinfection. Comicroinjection of viral RNA and fluorescent dextran in the presence of neutralizing virus antibody suggested that these protrusions mediated the spread of infection from one cell to another prior to virus-induced cell lysis. Altogether, the CVB3-induced cellular protrusions could function as a hitherto-unknown nonlytic mechanism of cell-to-cell transmission exploited by enteroviruses.
Assuntos
Proteínas do Capsídeo/metabolismo , Enterovirus Humano B/patogenicidade , Infecções por Enterovirus/transmissão , Infecções por Enterovirus/virologia , Rim/ultraestrutura , Rim/virologia , Proteínas Virais/metabolismo , Animais , Linhagem Celular , Enterovirus Humano B/fisiologia , Enterovirus Humano B/efeitos da radiação , Humanos , Imageamento Tridimensional , Rim/citologia , Microscopia EletrônicaRESUMO
The replication protein NS1 is essential for genome replication and protein production in parvoviral infection. Many of its functions, including recognition and site-specific nicking of the viral genome, helicase activity, and transactivation of the viral capsid promoter, are dependent on ATP. An ATP-binding pocket resides in the middle of the modular NS1 protein in a superfamily 3 helicase domain. Here we have identified key ATP-binding amino acid residues in canine parvovirus (CPV) NS1 protein and mutated amino acids from the conserved A motif (K406), B motif (E444 and E445), and positively charged region (R508 and R510). All mutations prevented the formation of infectious viruses. When provided in trans, all except the R508A mutation reduced infectivity in a dominant-negative manner, possibly by hindering genome replication. These results suggest that the conserved R510 residue, but not R508, is the arginine finger sensory element of CPV NS1. Moreover, fluorescence recovery after photobleaching (FRAP), complemented by computer simulations, was used to assess the binding properties of mutated fluorescent fusion proteins. These experiments identified ATP-dependent and -independent binding modes for NS1 in living cells. Only the K406M mutant had a single binding site, which was concluded to indicate ATP-independent binding. Furthermore, our data suggest that DNA binding of NS1 is dependent on its ability to both bind and hydrolyze ATP.
Assuntos
Trifosfato de Adenosina/metabolismo , Parvovirus Canino/fisiologia , Proteínas não Estruturais Virais/metabolismo , Sequência de Aminoácidos , Substituição de Aminoácidos/genética , Animais , Sítios de Ligação , Gatos , Linhagem Celular , Cães , Hidrólise , Modelos Moleculares , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Ligação Proteica , Estrutura Terciária de Proteína , Alinhamento de SequênciaRESUMO
Glucocorticoid (GC) receptor (GR) is a key transcription factor (TF) that regulates vital metabolic and anti-inflammatory processes. We have identified BCL6 corepressor (BCOR) as a dexamethasone-stimulated interaction partner of GR. BCOR is a component of non-canonical polycomb repressor complex 1.1 (ncPCR1.1) and linked to different developmental disorders and cancers, but the role of BCOR in GC signaling is poorly characterized. Here, using ChIP-seq we show that, GC induces genome-wide redistribution of BCOR chromatin binding towards GR-occupied enhancers in HEK293 cells. As assessed by RNA-seq, depletion of BCOR altered the expression of hundreds of GC-regulated genes, especially the ones linked to TNF signaling, GR signaling and cell migration pathways. Biotinylation-based proximity mapping revealed that GR and BCOR share several interacting partners, including nuclear receptor corepressor NCOR1. ChIP-seq showed that the NCOR1 co-occurs with both BCOR and GR on a subset of enhancers upon GC treatment. Simultaneous depletion of BCOR and NCOR1 influenced GR target gene expression in a combinatorial and gene-specific manner. Finally, we show using live cell imaging that the depletion of BCOR together with NCOR1 markedly enhances cell migration. Collectively, our data suggest BCOR as an important gene and pathway selective coregulator of GR transcriptional activity.
Assuntos
Proteínas Proto-Oncogênicas/metabolismo , Receptores de Glucocorticoides/genética , Proteínas Repressoras/metabolismo , Sítios de Ligação , Movimento Celular/genética , Proliferação de Células/genética , Imunoprecipitação da Cromatina , Dexametasona/farmacologia , Elementos Facilitadores Genéticos , Regulação da Expressão Gênica/efeitos dos fármacos , Células HEK293 , Humanos , Correpressor 1 de Receptor Nuclear/genética , Correpressor 1 de Receptor Nuclear/metabolismo , Mapas de Interação de Proteínas , Proteínas Proto-Oncogênicas/genética , Receptores de Glucocorticoides/metabolismo , Proteínas Repressoras/genéticaRESUMO
Treatment of prostate cancer confronts resistance to androgen receptor (AR)-targeted therapies. AR-associated coregulators and chromatin proteins hold a great potential for novel therapy targets. Here, we employed a powerful chromatin-directed proteomics approach termed ChIP-SICAP to uncover the composition of chromatin protein network, the chromatome, around endogenous AR in castration resistant prostate cancer (CRPC) cells. In addition to several expected AR coregulators, the chromatome contained many nuclear proteins not previously associated with the AR. In the context of androgen signaling in CRPC cells, we further investigated the role of a known AR-associated protein, a chromatin remodeler SMARCA4 and that of SIM2, a transcription factor without a previous association with AR. To understand their role in chromatin accessibility and AR target gene expression, we integrated data from ChIP-seq, RNA-seq, ATAC-seq and functional experiments. Despite the wide co-occurrence of SMARCA4 and AR on chromatin, depletion of SMARCA4 influenced chromatin accessibility and expression of a restricted set of AR target genes, especially those involved in cell morphogenetic changes in epithelial-mesenchymal transition. The depletion also inhibited the CRPC cell growth, validating SMARCA4's functional role in CRPC cells. Although silencing of SIM2 reduced chromatin accessibility similarly, it affected the expression of a much larger group of androgen-regulated genes, including those involved in cellular responses to external stimuli and steroid hormone stimulus. The silencing also reduced proliferation of CRPC cells and tumor size in chick embryo chorioallantoic membrane assay, further emphasizing the importance of SIM2 in CRPC cells and pointing to the functional relevance of this potential prostate cancer biomarker in CRPC cells. Overall, the chromatome of AR identified in this work is an important resource for the field focusing on this important drug target.
Assuntos
Receptores Androgênicos , Animais , Embrião de Galinha , Masculino , Próstata , ProteômicaRESUMO
We have identified BCL6 corepressor (BCOR) as a hormone-dependent interaction partner of androgen receptor (AR), a key transcription factor in the development of normal and cancerous prostate. BCOR is often mutated in cancers and hematological diseases and as a component of a non-canonical polycomb repressive complex 1 (ncPRC1.1) required for arranging many facets of cellular differentiation. However, its role in androgen signaling or prostate cancer cells remains unknown. Here, our genome-wide analyses reveal that BCOR is recruited in an androgen-dependent fashion to majority of AR-binding chromatin sites in castration-resistant prostate cancer (CRPC) cells. Interestingly, depletion of BCOR has a significant effect on the expression of androgen-repressed genes linked to regulation of cell proliferation, differentiation and development. At many of these genes, such as HOX genes, the depletion leads to a decrease in H2A K119 monoubiquitination and an increase in mRNA expression. Consistently, BCOR depletion impairs the proliferation and viability of CRPC cells, inducing their apoptosis. Collectively, our data indicate a key role for the BCOR-ncPRC1.1 complex in the corepression of an important subset of AR target genes and the regulation of prostate cancer cell proliferation.
Assuntos
Histonas/metabolismo , Neoplasias da Próstata/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Receptores Androgênicos/metabolismo , Proteínas Repressoras/metabolismo , Androgênios/farmacologia , Sítios de Ligação , Linhagem Celular Tumoral , Proliferação de Células/fisiologia , Cromatina/genética , Cromatina/metabolismo , Regulação Neoplásica da Expressão Gênica , Histonas/genética , Humanos , Masculino , Complexo Repressor Polycomb 1/genética , Complexo Repressor Polycomb 1/metabolismo , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia , Proteínas Proto-Oncogênicas/genética , Receptores Androgênicos/genética , Proteínas Repressoras/genética , UbiquitinaçãoRESUMO
Baculovirus, Autographa californica multiple nucleopolyhedrovirus (AcMNPV), has the ability to transduce mammalian cell lines without replication. The general objective of this study was to detect the transcription and expression of viral immediate-early genes in human cells and to examine the interactions between viral components and subnuclear structures. Viral capsids were seen in large, discrete foci in nuclei of both dividing and non-dividing human cells. Concurrently, the transcription of viral immediate-early transregulator genes (ie-1, ie-2) and translation of IE-2 protein were detected. Quantitative microscopy imaging and analysis showed that virus transduction altered the size of promyelocytic leukaemia nuclear bodies, which are suggested to be involved in replication and transcription of various viruses. Furthermore, altered distribution of the chromatin marker Draq5 and histone core protein (H2B) in transduced cells indicated that the virus was able to induce remodelling of the host cell chromatin. To conclude, this study shows that the non-replicative insect virus, baculovirus and its proteins can induce multiple changes in the cellular machinery of human cells.
Assuntos
Expressão Gênica , Genes Precoces , Nucleopoliedrovírus/genética , Proteínas Virais/biossíntese , Animais , Antraquinonas/metabolismo , Capsídeo/metabolismo , Linhagem Celular , Núcleo Celular/química , Núcleo Celular/virologia , Montagem e Desmontagem da Cromatina , Histonas/metabolismo , Humanos , Camundongos , Microscopia Confocal , Microscopia de FluorescênciaRESUMO
IRF2BP2 (interferon regulatory factor-2 binding protein-2) is an uncharacterized interaction partner of glucocorticoid (GC) receptor (GR), an anti-inflammatory and metabolic transcription factor. Here, we show that GC changes the chromatin binding of IRF2BP2 in natural chromatin milieu. The GC-induced IRF2BP2-binding sites co-occur with GR binding sites and are associated with GC-induced genes. Moreover, the depletion of IRF2BP2 modulates transcription of GC-regulated genes, represses cell proliferation and increases cell movement in HEK293 cells. In A549 cells, the depletion extensively alters the responses to GC and tumor necrosis factor α (TNF), including metabolic and inflammatory pathways. Taken together, our data support the role of IRF2BP2 as a coregulator of both GR and NF-κB, potentially modulating the crosstalk between GC and TNF signaling.