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Hamilton G, Stickler S, Rath B. Bromodomain Protein-directed Agents and MYC in Small Cell Lung Cancer. Curr Cancer Drug Targets 2024; 24:CCDT-EPUB-137831. [PMID: 38275056 DOI: 10.2174/0115680096272757231211113206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 10/17/2023] [Accepted: 11/13/2023] [Indexed: 01/27/2024]
Abstract
Small cell lung cancer (SCLC) has a dismal prognosis. In addition to the inactivation of the tumor suppressors TP53 and RB1, tumor-promoting MYC and paralogs are frequently overexpressed in this neuroendocrine carcinoma. SCLC exhibits high resistance to second-line chemotherapy and all attempts of novel drugs and targeted therapy have failed so far to achieve superior survival. MYC and paralogs have key roles in the oncogenic process, orchestrating proliferation, apoptosis, differentiation, and metabolism. In SCLC, MYC-L and MYC regulate the neuroendocrine dedifferentiation of SCLC cells from Type A (ASCL1 expression) to the other SCLC subtypes. Targeting MYC to suppress tumor growth is difficult due to the lack of suitable binding pockets and the most advanced miniprotein inhibitor Omomyc exhibits limited efficacy. MYC may be targeted indirectly via the bromodomain (BET) protein BRD4, which activates MYC transcription, by specific BET inhibitors that reduce the expression of this oncogenic driver. Here, novel BET-directed Proteolysis Targeting Chimeras (PROTACs) are discussed that show high antiproliferative activity in SCLC. Particularly ARV825, targeting specifically BRD4, exhibits superior cytotoxic effects on SCLC cell lines and may become a valuable adjunct to SCLC combination chemotherapy.
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Affiliation(s)
- Gerhard Hamilton
- Institute of Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Sandra Stickler
- Institute of Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Barbara Rath
- Institute of Pharmacology, Medical University of Vienna, Vienna, Austria
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Ashby EC, Havens JL, Rollosson LM, Hardin J, Schulz D. Chemical Inhibition of Bromodomain Proteins in Insect-Stage African Trypanosomes Perturbs Silencing of the Variant Surface Glycoprotein Repertoire and Results in Widespread Changes in the Transcriptome. Microbiol Spectr 2023; 11:e0014723. [PMID: 37097159 PMCID: PMC10269879 DOI: 10.1128/spectrum.00147-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 04/04/2023] [Indexed: 04/26/2023] Open
Abstract
The eukaryotic protozoan parasite Trypanosoma brucei is transmitted by the tsetse fly to both humans and animals, where it causes a fatal disease called African trypanosomiasis. While the parasite lacks canonical DNA sequence-specific transcription factors, it does possess histones, histone modifications, and proteins that write, erase, and read histone marks. Chemical inhibition of chromatin-interacting bromodomain proteins has previously been shown to perturb bloodstream specific trypanosome processes, including silencing of the variant surface glycoprotein (VSG) genes and immune evasion. Transcriptomic changes that occur in bromodomain-inhibited bloodstream parasites mirror many of the changes that occur as parasites developmentally progress from the bloodstream to the insect stage. We performed transcriptome sequencing (RNA-seq) time courses to determine the effects of chemical bromodomain inhibition in insect-stage parasites using the compound I-BET151. We found that treatment with I-BET151 causes large changes in the transcriptome of insect-stage parasites and also perturbs silencing of VSG genes. The transcriptomes of bromodomain-inhibited parasites share some features with early metacyclic-stage parasites in the fly salivary gland, implicating bromodomain proteins as important for regulating transcript levels for developmentally relevant genes. However, the downregulation of surface procyclin protein that typically accompanies developmental progression is absent in bromodomain-inhibited insect-stage parasites. We conclude that chemical modulation of bromodomain proteins causes widespread transcriptomic changes in multiple trypanosome life cycle stages. Understanding the gene-regulatory processes that facilitate transcriptome remodeling in this highly diverged eukaryote may shed light on how these mechanisms evolved. IMPORTANCE The disease African trypanosomiasis imposes a severe human and economic burden for communities in sub-Saharan Africa. The parasite that causes the disease is transmitted to the bloodstream of a human or ungulate via the tsetse fly. Because the environments of the fly and the bloodstream differ, the parasite modulates the expression of its genes to accommodate two different lifestyles in these disparate niches. Perturbation of bromodomain proteins that interact with histone proteins around which DNA is wrapped (chromatin) causes profound changes in gene expression in bloodstream-stage parasites. This paper reports that gene expression is also affected by chemical bromodomain inhibition in insect-stage parasites but that the genes affected differ depending on life cycle stage. Because trypanosomes diverged early from model eukaryotes, an understanding of how trypanosomes regulate gene expression may lend insight into how gene-regulatory mechanisms evolved. This could also be leveraged to generate new therapeutic strategies.
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Affiliation(s)
- Ethan C. Ashby
- Department of Biology, Harvey Mudd College, Claremont, California, USA
| | | | | | - Johanna Hardin
- Department of Mathematics and Statistics, Pomona College, Claremont, California, USA
| | - Danae Schulz
- Department of Biology, Harvey Mudd College, Claremont, California, USA
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Gatto L, Franceschi E, Tosoni A, Di Nunno V, Bartolini S, Brandes AA. Molecular Targeted Therapies: Time for a Paradigm Shift in Medulloblastoma Treatment? Cancers (Basel) 2022; 14:333. [PMID: 35053495 PMCID: PMC8773620 DOI: 10.3390/cancers14020333] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 01/06/2022] [Accepted: 01/07/2022] [Indexed: 12/11/2022] Open
Abstract
Medulloblastoma is a rare malignancy of the posterior cranial fossa. Although until now considered a single disease, according to the current WHO classification, it is a heterogeneous tumor that comprises multiple molecularly defined subgroups, with distinct gene expression profiles, pathogenetic driver alterations, clinical behaviors and age at onset. Adult medulloblastoma, in particular, is considered a rarer "orphan" entity in neuro-oncology practice because while treatments have progressively evolved for the pediatric population, no practice-changing prospective, randomized clinical trials have been performed in adults. In this scenario, the toughest challenge is to transfer the advances in cancer genomics into new molecularly targeted therapeutics, to improve the prognosis of this neoplasm and the treatment-related toxicities. Herein, we focus on the recent advances in targeted therapy of medulloblastoma based on the new and deeper knowledge of disease biology.
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Affiliation(s)
- Lidia Gatto
- Medical Oncology Department, Azienda Unità Sanitaria Locale, 40139 Bologna, Italy; (L.G.); (V.D.N.)
| | - Enrico Franceschi
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Oncologia Medica del Sistema Nervoso, 40139 Bologna, Italy; (A.T.); (S.B.); (A.A.B.)
| | - Alicia Tosoni
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Oncologia Medica del Sistema Nervoso, 40139 Bologna, Italy; (A.T.); (S.B.); (A.A.B.)
| | - Vincenzo Di Nunno
- Medical Oncology Department, Azienda Unità Sanitaria Locale, 40139 Bologna, Italy; (L.G.); (V.D.N.)
| | - Stefania Bartolini
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Oncologia Medica del Sistema Nervoso, 40139 Bologna, Italy; (A.T.); (S.B.); (A.A.B.)
| | - Alba Ariela Brandes
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Oncologia Medica del Sistema Nervoso, 40139 Bologna, Italy; (A.T.); (S.B.); (A.A.B.)
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Snoznik C, Medvedeva V, Mojsilovic-Petrovic J, Rudich P, Oosten J, Kalb RG, Lamitina T. The nuclear ubiquitin ligase adaptor SPOP is a conserved regulator of C9orf72 dipeptide toxicity. Proc Natl Acad Sci U S A 2021; 118:e2104664118. [PMID: 34593637 DOI: 10.1073/pnas.2104664118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/06/2021] [Indexed: 12/29/2022] Open
Abstract
A hexanucleotide repeat expansion in the C9orf72 gene is the most common cause of inherited amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Unconventional translation of the C9orf72 repeat produces dipeptide repeat proteins (DPRs). Previously, we showed that the DPRs PR50 and GR50 are highly toxic when expressed in Caenorhabditis elegans, and this toxicity depends on nuclear localization of the DPR. In an unbiased genome-wide RNA interference (RNAi) screen for suppressors of PR50 toxicity, we identified 12 genes that consistently suppressed either the developmental arrest and/or paralysis phenotype evoked by PR50 expression. All of these genes have vertebrate homologs, and 7 of 12 contain predicted nuclear localization signals. One of these genes was spop-1, the C. elegans homolog of SPOP, a nuclear localized E3 ubiquitin ligase adaptor only found in metazoans. SPOP is also required for GR50 toxicity and functions in a genetic pathway that includes cul-3, which is the canonical E3 ligase partner for SPOP Genetic or pharmacological inhibition of SPOP in mammalian primary spinal cord motor neurons suppressed DPR toxicity without affecting DPR expression levels. Finally, we find that knockdown of bromodomain proteins in both C. elegans and mammalian neurons, which are known SPOP ubiquitination targets, suppresses the protective effect of SPOP inhibition. Together, these data suggest a model in which SPOP promotes the DPR-dependent ubiquitination and degradation of BRD proteins. We speculate the pharmacological manipulation of this pathway, which is currently underway for multiple cancer subtypes, could also represent an entry point for therapeutic intervention to treat C9orf72 FTD/ALS.
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Abstract
Rheumatoid arthritis is a complex, inflammatory autoimmune disease, which is characterized by pain, swelling and joint damage driven by the altered behavior of a number of different cell types such as synovial fibroblasts macrophages and lymphocytes. The mechanism underlying pathogenesis is unclear but increasing evidence points to altered epigenetic regulation within these cell types which promotes the activated destructive behavior that underlies disease pathogenesis. This review summarizes the key epigenetic modifications in the most important cells types in rheumatoid arthritis, which are associated with disease activity. We also discuss emerging avenues of research focusing on readers of epigenetic markers which may serve to be potential therapeutic targets.
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Affiliation(s)
- Nisha Nair
- Centre for Genetics & Genomics Versus Arthritis, Centre for Musculoskeletal Research, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, M13 9PT, UK
| | - Anne Barton
- Centre for Genetics & Genomics Versus Arthritis, Centre for Musculoskeletal Research, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, M13 9PT, UK.,NIHR Manchester Musculoskeletal BRU, Central Manchester Foundation Trust, Manchester Academic Health Sciences Centre, Manchester, M13 9WL, UK
| | - Anthony G Wilson
- University College Dublin School of Medicine & Medical Science, Conway Institute, University College Dublin, Dublin 4, Ireland
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Groves IJ, Jackson SE, Poole EL, Nachshon A, Rozman B, Schwartz M, Prinjha RK, Tough DF, Sinclair JH, Wills MR. Bromodomain proteins regulate human cytomegalovirus latency and reactivation allowing epigenetic therapeutic intervention. Proc Natl Acad Sci U S A 2021; 118:e2023025118. [PMID: 33619107 PMCID: PMC7936348 DOI: 10.1073/pnas.2023025118] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Reactivation of human cytomegalovirus (HCMV) from latency is a major health consideration for recipients of stem-cell and solid organ transplantations. With over 200,000 transplants taking place globally per annum, virus reactivation can occur in more than 50% of cases leading to loss of grafts as well as serious morbidity and even mortality. Here, we present the most extensive screening to date of epigenetic inhibitors on HCMV latently infected cells and find that histone deacetylase inhibitors (HDACis) and bromodomain inhibitors are broadly effective at inducing virus immediate early gene expression. However, while HDACis, such as myeloid-selective CHR-4487, lead to production of infectious virions, inhibitors of bromodomain (BRD) and extraterminal proteins (I-BETs), including GSK726, restrict full reactivation. Mechanistically, we show that BET proteins (BRDs) are pivotally connected to regulation of HCMV latency and reactivation. Through BRD4 interaction, the transcriptional activator complex P-TEFb (CDK9/CycT1) is sequestered by repressive complexes during HCMV latency. Consequently, I-BETs allow release of P-TEFb and subsequent recruitment to promoters via the superelongation complex (SEC), inducing transcription of HCMV lytic genes encoding immunogenic antigens from otherwise latently infected cells. Surprisingly, this occurs without inducing many viral immunoevasins and, importantly, while also restricting viral DNA replication and full HCMV reactivation. Therefore, this pattern of HCMV transcriptional dysregulation allows effective cytotoxic immune targeting and killing of latently infected cells, thus reducing the latent virus genome load. This approach could be safely used to pre-emptively purge the virus latent reservoir prior to transplantation, thereby reducing HCMV reactivation-related morbidity and mortality.
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MESH Headings
- Azepines/pharmacology
- Bacterial Proteins/genetics
- Bacterial Proteins/metabolism
- Benzodiazepines/pharmacology
- Cell Cycle Proteins/antagonists & inhibitors
- Cell Cycle Proteins/genetics
- Cell Cycle Proteins/immunology
- Cyclin T/genetics
- Cyclin T/immunology
- Cyclin-Dependent Kinase 9/genetics
- Cyclin-Dependent Kinase 9/immunology
- Cytomegalovirus/drug effects
- Cytomegalovirus/genetics
- Cytomegalovirus/immunology
- Cytomegalovirus Infections/genetics
- Cytomegalovirus Infections/immunology
- Cytomegalovirus Infections/pathology
- DNA Replication/drug effects
- DNA, Viral/antagonists & inhibitors
- DNA, Viral/genetics
- DNA, Viral/immunology
- Epigenesis, Genetic
- Genes, Immediate-Early
- Genes, Reporter
- Histone Deacetylase Inhibitors/pharmacology
- Histone Deacetylases/genetics
- Histone Deacetylases/immunology
- Host-Pathogen Interactions
- Humans
- Luminescent Proteins/genetics
- Luminescent Proteins/metabolism
- Models, Biological
- Positive Transcriptional Elongation Factor B/genetics
- Positive Transcriptional Elongation Factor B/immunology
- Primary Cell Culture
- Promoter Regions, Genetic
- T-Lymphocytes, Cytotoxic/drug effects
- T-Lymphocytes, Cytotoxic/immunology
- T-Lymphocytes, Cytotoxic/virology
- THP-1 Cells
- Thalidomide/analogs & derivatives
- Thalidomide/pharmacology
- Transcription Factors/antagonists & inhibitors
- Transcription Factors/genetics
- Transcription Factors/immunology
- Transcription, Genetic
- Virus Activation/drug effects
- Virus Latency/drug effects
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Affiliation(s)
- Ian J Groves
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge, CB2 0QQ, United Kingdom;
| | - Sarah E Jackson
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge, CB2 0QQ, United Kingdom
| | - Emma L Poole
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge, CB2 0QQ, United Kingdom
| | - Aharon Nachshon
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Batsheva Rozman
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Michal Schwartz
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Rab K Prinjha
- Adaptive Immunity Research Unit, GlaxoSmithKline Medicines Research Centre, Stevenage, SG1 2NY, United Kingdom
| | - David F Tough
- Adaptive Immunity Research Unit, GlaxoSmithKline Medicines Research Centre, Stevenage, SG1 2NY, United Kingdom
| | - John H Sinclair
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge, CB2 0QQ, United Kingdom
| | - Mark R Wills
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge, CB2 0QQ, United Kingdom;
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Abstract
R-loops are intermediate structures of transcription that can accumulate when transcriptional elongation is blocked by inhibiting BRD4. In normal cells, R-loop persistence suppresses firing of adjacent replication origins. This control is lost in a subset of cancer cells, where BRD4 inhibition results in R-loop accumulation, leading to transcription-replication collisions and DNA double-strand breaks during S-phase, followed by cell death. This finding sheds new light on the mechanisms by which BRD4 inhibitors function as cancer therapies, and indicates that targeting other cellular events to cause R-loop accumulation may be useful for cancer treatment.
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Affiliation(s)
- Fred C. Lam
- Division of Neurosurgery, Hamilton General Hospital, McMaster University Faculty of Health Sciences, Hamilton, Ontario, Canada
- Center for Precision Cancer Medicine at MIT, Cambridge, MA, USA
- Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA, USA
- Departments of Biology and Bioengineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Yi Wen Kong
- Center for Precision Cancer Medicine at MIT, Cambridge, MA, USA
- Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA, USA
- Departments of Biology and Bioengineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Michael B. Yaffe
- Center for Precision Cancer Medicine at MIT, Cambridge, MA, USA
- Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA, USA
- Departments of Biology and Bioengineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Beth Israel Deaconess Medical Center, Department of Surgery, Harvard Medical School, Boston, MA, USA
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Jostes S, Nettersheim D, Fellermeyer M, Schneider S, Hafezi F, Honecker F, Schumacher V, Geyer M, Kristiansen G, Schorle H. The bromodomain inhibitor JQ1 triggers growth arrest and apoptosis in testicular germ cell tumours in vitro and in vivo. J Cell Mol Med 2016; 21:1300-1314. [PMID: 28026145 PMCID: PMC5487916 DOI: 10.1111/jcmm.13059] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 11/15/2016] [Indexed: 12/21/2022] Open
Abstract
Type II testicular germ cell cancers (TGCT) are the most frequently diagnosed tumours in young men (20–40 years) and are classified as seminoma or non‐seminoma. TGCTs are commonly treated by orchiectomy and chemo‐ or radiotherapy. However, a subset of metastatic non‐seminomas (embryonal carcinomas) displays only incomplete remission or relapse and requires novel treatment options. Recent studies have shown effective application of the small‐molecule inhibitor JQ1 in tumour therapy, which interferes with the function of ‘bromodomain and extraterminal (BET)’ proteins. JQ1‐treated TGCT cell lines display up‐regulation of genes indicative for DNA damage and cellular stress response and induce cell cycle arrest. Embryonal carcinoma (EC) cell lines, which presented as JQ1 sensitive, display down‐regulation of pluripotency factors and induction of mesodermal differentiation. In contrast, seminoma‐like TCam‐2 cells tolerated higher JQ1 concentrations and were resistant to differentiation. ECs xenografted in vivo showed a reduction in tumour size, proliferation rate and angiogenesis in response to JQ1. Finally, the combination of JQ1 and the histone deacetylase inhibitor romidepsin allowed for lower doses and less frequent application, compared with monotherapy. Thus, we propose that JQ1 in combination with romidepsin may serve as a novel therapeutic option for (mixed) TGCTs.
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Affiliation(s)
- Sina Jostes
- Institute of Pathology, Department of Developmental Pathology, University Medical School, Bonn, Germany
| | - Daniel Nettersheim
- Institute of Pathology, Department of Developmental Pathology, University Medical School, Bonn, Germany
| | - Martin Fellermeyer
- Institute of Pathology, Department of Developmental Pathology, University Medical School, Bonn, Germany
| | - Simon Schneider
- Institute of Pathology, Department of Developmental Pathology, University Medical School, Bonn, Germany
| | - François Hafezi
- Institute of Pathology, Department of Developmental Pathology, University Medical School, Bonn, Germany
| | | | - Valerie Schumacher
- Department of Urology, Boston Children's Hospital, Boston, MA, USA.,Department of Surgery, Harvard Medical School, Boston, MA, USA
| | - Matthias Geyer
- Institute of Innate Immunity, Department of Structural Immunology, University Medical School, Bonn, Germany
| | - Glen Kristiansen
- Institute of Pathology, University Medical School, Bonn, Germany
| | - Hubert Schorle
- Institute of Pathology, Department of Developmental Pathology, University Medical School, Bonn, Germany
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