author_facet Weigel, Christoph
Assenov, Yassen
Imbusch, Charles
Wang, Qi
Beekman, Renée
Giacopelli, Brian
Wu, Yue-zhong
Brocks, David
Dieter, Weichenhan
Odilia, Popanda
Schmezer, Peter
Brors, Benedikt
Mertens, Daniel
Rippe, Karsten
Rassenti, Laura Z.
Kipps, Thomas J.
Woyach, Jennifer A.
Blachly, James S.
Campo, Elias
Zenz, Thorsten
Byrd, John C.
Martin-Subero, José I.
Plass, Christoph
Oakes, Christopher C.
Weigel, Christoph
Assenov, Yassen
Imbusch, Charles
Wang, Qi
Beekman, Renée
Giacopelli, Brian
Wu, Yue-zhong
Brocks, David
Dieter, Weichenhan
Odilia, Popanda
Schmezer, Peter
Brors, Benedikt
Mertens, Daniel
Rippe, Karsten
Rassenti, Laura Z.
Kipps, Thomas J.
Woyach, Jennifer A.
Blachly, James S.
Campo, Elias
Zenz, Thorsten
Byrd, John C.
Martin-Subero, José I.
Plass, Christoph
Oakes, Christopher C.
author Weigel, Christoph
Assenov, Yassen
Imbusch, Charles
Wang, Qi
Beekman, Renée
Giacopelli, Brian
Wu, Yue-zhong
Brocks, David
Dieter, Weichenhan
Odilia, Popanda
Schmezer, Peter
Brors, Benedikt
Mertens, Daniel
Rippe, Karsten
Rassenti, Laura Z.
Kipps, Thomas J.
Woyach, Jennifer A.
Blachly, James S.
Campo, Elias
Zenz, Thorsten
Byrd, John C.
Martin-Subero, José I.
Plass, Christoph
Oakes, Christopher C.
spellingShingle Weigel, Christoph
Assenov, Yassen
Imbusch, Charles
Wang, Qi
Beekman, Renée
Giacopelli, Brian
Wu, Yue-zhong
Brocks, David
Dieter, Weichenhan
Odilia, Popanda
Schmezer, Peter
Brors, Benedikt
Mertens, Daniel
Rippe, Karsten
Rassenti, Laura Z.
Kipps, Thomas J.
Woyach, Jennifer A.
Blachly, James S.
Campo, Elias
Zenz, Thorsten
Byrd, John C.
Martin-Subero, José I.
Plass, Christoph
Oakes, Christopher C.
Blood
Recurrent Mutations in EGR2 Direct Specific Epigenetic Reconfiguration in Chronic Lymphocytic Leukemia
Cell Biology
Hematology
Immunology
Biochemistry
author_sort weigel, christoph
spelling Weigel, Christoph Assenov, Yassen Imbusch, Charles Wang, Qi Beekman, Renée Giacopelli, Brian Wu, Yue-zhong Brocks, David Dieter, Weichenhan Odilia, Popanda Schmezer, Peter Brors, Benedikt Mertens, Daniel Rippe, Karsten Rassenti, Laura Z. Kipps, Thomas J. Woyach, Jennifer A. Blachly, James S. Campo, Elias Zenz, Thorsten Byrd, John C. Martin-Subero, José I. Plass, Christoph Oakes, Christopher C. 0006-4971 1528-0020 American Society of Hematology Cell Biology Hematology Immunology Biochemistry http://dx.doi.org/10.1182/blood-2018-99-119070 <jats:title>Abstract</jats:title> <jats:p>Epigenetic alterations are universal in cancer and are important in establishing the malignant phenotype. Dissection of the factors that shape the tumor-specific epigenome may reveal insight into key aspects of tumorigenesis and therapeutic resistance. In chronic lymphocytic leukemia (CLL), we have previously found that broad changes in epigenetic patterns co-occur with the evolution of genetic alterations. We have also uncovered that aberrant patterning of DNA methylation in CLL involves excessive activity of a defined group of transcription factors (TFs), including the early growth response (EGR) TF family. Recent work has further revealed that recurrent mutations in EGR2 are associated with exceptionally poor clinical outcomes in CLL. The basis for the adverse association of EGR2 mutations in CLL is unclear.</jats:p> <jats:p>To explore the role of EGR2 mutations in CLL, we initially performed genome-wide DNA methylation analysis using Illumina arrays on CLL patients harboring EGR2 mutations (n=27) compared to EGR wild-type cases (n=265). We found that the three most common recurrent mutations, occurring at amino acid positions E356K, H384N and D411H within the DNA binding domain, are each associated with an exclusive subset of tumor-specific hypomethylated CpG sites. A search for TF sequence motifs at these loci revealed a strong enrichment of novel derivative EGR2 motifs that differ only marginally (usually by a single nucleotide) from the canonical EGR2 recognition sequence. Each recurrent mutation led to specific enrichment of a different derivative EGR2 motif. Furthermore, the canonical (wild-type) recognition sequence was not enriched, suggesting that mutations re-localize binding activity to derivate sequence motifs rather than simply altering binding affinity. Luciferase enhancer, proximity ligation and electrophoretic mobility shift assays confirmed that each EGR2 mutant protein specifically binds and enhances transcriptional activity only when the matched EGR2 derivative recognition motif is present. These results establish that derivative motif sequences may function as novel cryptic enhancers in the presence of the cognate EGR2 mutant TF.</jats:p> <jats:p>We performed multiomics profiling (DNA methylome, ATAC-seq, ChIP-seq and RNA-seq) to examine the nature of the epigenetic reconfiguration and the phenotypic impact of individual EGR2 mutations. Whole genome bisulfite sequencing of E356K- and H384N-mutated CLL samples (n=4 each) was used to reveal the full complement of recurrent differentially methylated regions (DMRs) across the genome, and recapitulated the mutually-exclusive pattern of DMRs between mutations. Overlaying DMRs with data from ChIP-seq and ATAC-seq experiments in the same samples revealed the nature of EGR2 mutation-specific chromatin reconfiguration to be remarkably mutation-specific. For E356K, hypomethylated DMRs are often associated with foci of accessible chromatin, EGR2 binding, and flanked by gains of H3K4me1 and H3K27ac, indicative of the acquisition of active enhancer function. Conversely, H384N mutations generated fewer DMRs and mainly directed the deposition of H3K4me1 only, indicative of gain of poised enhancers at these loci. RNA-sequencing analyses revealed that a subset of epigenetically reconfigured regions was associated with mutation-specific altered gene expression, and differences were virtually always associated with proximal gene activation. E356K and H384N mutations displayed highly differential gene expression patterns, with E356K exhibiting a greater impact on gene expression. Integrated analyses indicated that E356K mutations may specifically involve activated Notch signaling, revealed by the aberrant activation of Notch target genes and the mutual exclusivity of NOTCH1 mutations, further highlighted by enriched co-mutation of NOTCH1 in H384N-mutated CLL.</jats:p> <jats:p>Together these findings provide an exceptional example of the precise role that a singular TF may play in programming the epigenetic landscape. As there are no known TFs that naturally bind derivative EGR2 motifs, these mutant proteins provide insight into aberrant enhancer generation and the phenotypic impact of (re)directed TF binding in a human disease setting. Although these recurrent mutations are presently only known in CLL, these findings provide insight into the mechanisms that may surround other gain-of-function TF activity in various malignancies.</jats:p> <jats:sec> <jats:title>Disclosures</jats:title> <jats:p>Kipps: Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Verastem: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Consultancy, Honoraria, Research Funding; Genentech Inc: Consultancy, Research Funding; Pharmacyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy; F. Hoffmann-La Roche Ltd: Consultancy, Research Funding; Verastem: Membership on an entity's Board of Directors or advisory committees.</jats:p> </jats:sec> Recurrent Mutations in EGR2 Direct Specific Epigenetic Reconfiguration in Chronic Lymphocytic Leukemia Blood
doi_str_mv 10.1182/blood-2018-99-119070
facet_avail Online
Free
finc_class_facet Biologie
Medizin
Chemie und Pharmazie
format ElectronicArticle
fullrecord blob:ai-49-aHR0cDovL2R4LmRvaS5vcmcvMTAuMTE4Mi9ibG9vZC0yMDE4LTk5LTExOTA3MA
id ai-49-aHR0cDovL2R4LmRvaS5vcmcvMTAuMTE4Mi9ibG9vZC0yMDE4LTk5LTExOTA3MA
institution DE-Pl11
DE-Rs1
DE-105
DE-14
DE-Ch1
DE-L229
DE-D275
DE-Bn3
DE-Brt1
DE-D161
DE-Zwi2
DE-Gla1
DE-Zi4
DE-15
imprint American Society of Hematology, 2018
imprint_str_mv American Society of Hematology, 2018
issn 0006-4971
1528-0020
issn_str_mv 0006-4971
1528-0020
language English
mega_collection American Society of Hematology (CrossRef)
match_str weigel2018recurrentmutationsinegr2directspecificepigeneticreconfigurationinchroniclymphocyticleukemia
publishDateSort 2018
publisher American Society of Hematology
recordtype ai
record_format ai
series Blood
source_id 49
title Recurrent Mutations in EGR2 Direct Specific Epigenetic Reconfiguration in Chronic Lymphocytic Leukemia
title_unstemmed Recurrent Mutations in EGR2 Direct Specific Epigenetic Reconfiguration in Chronic Lymphocytic Leukemia
title_full Recurrent Mutations in EGR2 Direct Specific Epigenetic Reconfiguration in Chronic Lymphocytic Leukemia
title_fullStr Recurrent Mutations in EGR2 Direct Specific Epigenetic Reconfiguration in Chronic Lymphocytic Leukemia
title_full_unstemmed Recurrent Mutations in EGR2 Direct Specific Epigenetic Reconfiguration in Chronic Lymphocytic Leukemia
title_short Recurrent Mutations in EGR2 Direct Specific Epigenetic Reconfiguration in Chronic Lymphocytic Leukemia
title_sort recurrent mutations in egr2 direct specific epigenetic reconfiguration in chronic lymphocytic leukemia
topic Cell Biology
Hematology
Immunology
Biochemistry
url http://dx.doi.org/10.1182/blood-2018-99-119070
publishDate 2018
physical 650-650
description <jats:title>Abstract</jats:title> <jats:p>Epigenetic alterations are universal in cancer and are important in establishing the malignant phenotype. Dissection of the factors that shape the tumor-specific epigenome may reveal insight into key aspects of tumorigenesis and therapeutic resistance. In chronic lymphocytic leukemia (CLL), we have previously found that broad changes in epigenetic patterns co-occur with the evolution of genetic alterations. We have also uncovered that aberrant patterning of DNA methylation in CLL involves excessive activity of a defined group of transcription factors (TFs), including the early growth response (EGR) TF family. Recent work has further revealed that recurrent mutations in EGR2 are associated with exceptionally poor clinical outcomes in CLL. The basis for the adverse association of EGR2 mutations in CLL is unclear.</jats:p> <jats:p>To explore the role of EGR2 mutations in CLL, we initially performed genome-wide DNA methylation analysis using Illumina arrays on CLL patients harboring EGR2 mutations (n=27) compared to EGR wild-type cases (n=265). We found that the three most common recurrent mutations, occurring at amino acid positions E356K, H384N and D411H within the DNA binding domain, are each associated with an exclusive subset of tumor-specific hypomethylated CpG sites. A search for TF sequence motifs at these loci revealed a strong enrichment of novel derivative EGR2 motifs that differ only marginally (usually by a single nucleotide) from the canonical EGR2 recognition sequence. Each recurrent mutation led to specific enrichment of a different derivative EGR2 motif. Furthermore, the canonical (wild-type) recognition sequence was not enriched, suggesting that mutations re-localize binding activity to derivate sequence motifs rather than simply altering binding affinity. Luciferase enhancer, proximity ligation and electrophoretic mobility shift assays confirmed that each EGR2 mutant protein specifically binds and enhances transcriptional activity only when the matched EGR2 derivative recognition motif is present. These results establish that derivative motif sequences may function as novel cryptic enhancers in the presence of the cognate EGR2 mutant TF.</jats:p> <jats:p>We performed multiomics profiling (DNA methylome, ATAC-seq, ChIP-seq and RNA-seq) to examine the nature of the epigenetic reconfiguration and the phenotypic impact of individual EGR2 mutations. Whole genome bisulfite sequencing of E356K- and H384N-mutated CLL samples (n=4 each) was used to reveal the full complement of recurrent differentially methylated regions (DMRs) across the genome, and recapitulated the mutually-exclusive pattern of DMRs between mutations. Overlaying DMRs with data from ChIP-seq and ATAC-seq experiments in the same samples revealed the nature of EGR2 mutation-specific chromatin reconfiguration to be remarkably mutation-specific. For E356K, hypomethylated DMRs are often associated with foci of accessible chromatin, EGR2 binding, and flanked by gains of H3K4me1 and H3K27ac, indicative of the acquisition of active enhancer function. Conversely, H384N mutations generated fewer DMRs and mainly directed the deposition of H3K4me1 only, indicative of gain of poised enhancers at these loci. RNA-sequencing analyses revealed that a subset of epigenetically reconfigured regions was associated with mutation-specific altered gene expression, and differences were virtually always associated with proximal gene activation. E356K and H384N mutations displayed highly differential gene expression patterns, with E356K exhibiting a greater impact on gene expression. Integrated analyses indicated that E356K mutations may specifically involve activated Notch signaling, revealed by the aberrant activation of Notch target genes and the mutual exclusivity of NOTCH1 mutations, further highlighted by enriched co-mutation of NOTCH1 in H384N-mutated CLL.</jats:p> <jats:p>Together these findings provide an exceptional example of the precise role that a singular TF may play in programming the epigenetic landscape. As there are no known TFs that naturally bind derivative EGR2 motifs, these mutant proteins provide insight into aberrant enhancer generation and the phenotypic impact of (re)directed TF binding in a human disease setting. Although these recurrent mutations are presently only known in CLL, these findings provide insight into the mechanisms that may surround other gain-of-function TF activity in various malignancies.</jats:p> <jats:sec> <jats:title>Disclosures</jats:title> <jats:p>Kipps: Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Verastem: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Consultancy, Honoraria, Research Funding; Genentech Inc: Consultancy, Research Funding; Pharmacyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy; F. Hoffmann-La Roche Ltd: Consultancy, Research Funding; Verastem: Membership on an entity's Board of Directors or advisory committees.</jats:p> </jats:sec>
container_issue Supplement 1
container_start_page 650
container_title Blood
container_volume 132
format_de105 Article, E-Article
format_de14 Article, E-Article
format_de15 Article, E-Article
format_de520 Article, E-Article
format_de540 Article, E-Article
format_dech1 Article, E-Article
format_ded117 Article, E-Article
format_degla1 E-Article
format_del152 Buch
format_del189 Article, E-Article
format_dezi4 Article
format_dezwi2 Article, E-Article
format_finc Article, E-Article
format_nrw Article, E-Article
_version_ 1792324046779580416
geogr_code not assigned
last_indexed 2024-03-01T11:43:29.904Z
geogr_code_person not assigned
openURL url_ver=Z39.88-2004&ctx_ver=Z39.88-2004&ctx_enc=info%3Aofi%2Fenc%3AUTF-8&rfr_id=info%3Asid%2Fvufind.svn.sourceforge.net%3Agenerator&rft.title=Recurrent+Mutations+in+EGR2+Direct+Specific+Epigenetic+Reconfiguration+in+Chronic+Lymphocytic+Leukemia&rft.date=2018-11-29&genre=article&issn=1528-0020&volume=132&issue=Supplement+1&spage=650&epage=650&pages=650-650&jtitle=Blood&atitle=Recurrent+Mutations+in+EGR2+Direct+Specific+Epigenetic+Reconfiguration+in+Chronic+Lymphocytic+Leukemia&aulast=Oakes&aufirst=Christopher+C.&rft_id=info%3Adoi%2F10.1182%2Fblood-2018-99-119070&rft.language%5B0%5D=eng
SOLR
_version_ 1792324046779580416
author Weigel, Christoph, Assenov, Yassen, Imbusch, Charles, Wang, Qi, Beekman, Renée, Giacopelli, Brian, Wu, Yue-zhong, Brocks, David, Dieter, Weichenhan, Odilia, Popanda, Schmezer, Peter, Brors, Benedikt, Mertens, Daniel, Rippe, Karsten, Rassenti, Laura Z., Kipps, Thomas J., Woyach, Jennifer A., Blachly, James S., Campo, Elias, Zenz, Thorsten, Byrd, John C., Martin-Subero, José I., Plass, Christoph, Oakes, Christopher C.
author_facet Weigel, Christoph, Assenov, Yassen, Imbusch, Charles, Wang, Qi, Beekman, Renée, Giacopelli, Brian, Wu, Yue-zhong, Brocks, David, Dieter, Weichenhan, Odilia, Popanda, Schmezer, Peter, Brors, Benedikt, Mertens, Daniel, Rippe, Karsten, Rassenti, Laura Z., Kipps, Thomas J., Woyach, Jennifer A., Blachly, James S., Campo, Elias, Zenz, Thorsten, Byrd, John C., Martin-Subero, José I., Plass, Christoph, Oakes, Christopher C., Weigel, Christoph, Assenov, Yassen, Imbusch, Charles, Wang, Qi, Beekman, Renée, Giacopelli, Brian, Wu, Yue-zhong, Brocks, David, Dieter, Weichenhan, Odilia, Popanda, Schmezer, Peter, Brors, Benedikt, Mertens, Daniel, Rippe, Karsten, Rassenti, Laura Z., Kipps, Thomas J., Woyach, Jennifer A., Blachly, James S., Campo, Elias, Zenz, Thorsten, Byrd, John C., Martin-Subero, José I., Plass, Christoph, Oakes, Christopher C.
author_sort weigel, christoph
container_issue Supplement 1
container_start_page 650
container_title Blood
container_volume 132
description <jats:title>Abstract</jats:title> <jats:p>Epigenetic alterations are universal in cancer and are important in establishing the malignant phenotype. Dissection of the factors that shape the tumor-specific epigenome may reveal insight into key aspects of tumorigenesis and therapeutic resistance. In chronic lymphocytic leukemia (CLL), we have previously found that broad changes in epigenetic patterns co-occur with the evolution of genetic alterations. We have also uncovered that aberrant patterning of DNA methylation in CLL involves excessive activity of a defined group of transcription factors (TFs), including the early growth response (EGR) TF family. Recent work has further revealed that recurrent mutations in EGR2 are associated with exceptionally poor clinical outcomes in CLL. The basis for the adverse association of EGR2 mutations in CLL is unclear.</jats:p> <jats:p>To explore the role of EGR2 mutations in CLL, we initially performed genome-wide DNA methylation analysis using Illumina arrays on CLL patients harboring EGR2 mutations (n=27) compared to EGR wild-type cases (n=265). We found that the three most common recurrent mutations, occurring at amino acid positions E356K, H384N and D411H within the DNA binding domain, are each associated with an exclusive subset of tumor-specific hypomethylated CpG sites. A search for TF sequence motifs at these loci revealed a strong enrichment of novel derivative EGR2 motifs that differ only marginally (usually by a single nucleotide) from the canonical EGR2 recognition sequence. Each recurrent mutation led to specific enrichment of a different derivative EGR2 motif. Furthermore, the canonical (wild-type) recognition sequence was not enriched, suggesting that mutations re-localize binding activity to derivate sequence motifs rather than simply altering binding affinity. Luciferase enhancer, proximity ligation and electrophoretic mobility shift assays confirmed that each EGR2 mutant protein specifically binds and enhances transcriptional activity only when the matched EGR2 derivative recognition motif is present. These results establish that derivative motif sequences may function as novel cryptic enhancers in the presence of the cognate EGR2 mutant TF.</jats:p> <jats:p>We performed multiomics profiling (DNA methylome, ATAC-seq, ChIP-seq and RNA-seq) to examine the nature of the epigenetic reconfiguration and the phenotypic impact of individual EGR2 mutations. Whole genome bisulfite sequencing of E356K- and H384N-mutated CLL samples (n=4 each) was used to reveal the full complement of recurrent differentially methylated regions (DMRs) across the genome, and recapitulated the mutually-exclusive pattern of DMRs between mutations. Overlaying DMRs with data from ChIP-seq and ATAC-seq experiments in the same samples revealed the nature of EGR2 mutation-specific chromatin reconfiguration to be remarkably mutation-specific. For E356K, hypomethylated DMRs are often associated with foci of accessible chromatin, EGR2 binding, and flanked by gains of H3K4me1 and H3K27ac, indicative of the acquisition of active enhancer function. Conversely, H384N mutations generated fewer DMRs and mainly directed the deposition of H3K4me1 only, indicative of gain of poised enhancers at these loci. RNA-sequencing analyses revealed that a subset of epigenetically reconfigured regions was associated with mutation-specific altered gene expression, and differences were virtually always associated with proximal gene activation. E356K and H384N mutations displayed highly differential gene expression patterns, with E356K exhibiting a greater impact on gene expression. Integrated analyses indicated that E356K mutations may specifically involve activated Notch signaling, revealed by the aberrant activation of Notch target genes and the mutual exclusivity of NOTCH1 mutations, further highlighted by enriched co-mutation of NOTCH1 in H384N-mutated CLL.</jats:p> <jats:p>Together these findings provide an exceptional example of the precise role that a singular TF may play in programming the epigenetic landscape. As there are no known TFs that naturally bind derivative EGR2 motifs, these mutant proteins provide insight into aberrant enhancer generation and the phenotypic impact of (re)directed TF binding in a human disease setting. Although these recurrent mutations are presently only known in CLL, these findings provide insight into the mechanisms that may surround other gain-of-function TF activity in various malignancies.</jats:p> <jats:sec> <jats:title>Disclosures</jats:title> <jats:p>Kipps: Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Verastem: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Consultancy, Honoraria, Research Funding; Genentech Inc: Consultancy, Research Funding; Pharmacyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy; F. Hoffmann-La Roche Ltd: Consultancy, Research Funding; Verastem: Membership on an entity's Board of Directors or advisory committees.</jats:p> </jats:sec>
doi_str_mv 10.1182/blood-2018-99-119070
facet_avail Online, Free
finc_class_facet Biologie, Medizin, Chemie und Pharmazie
format ElectronicArticle
format_de105 Article, E-Article
format_de14 Article, E-Article
format_de15 Article, E-Article
format_de520 Article, E-Article
format_de540 Article, E-Article
format_dech1 Article, E-Article
format_ded117 Article, E-Article
format_degla1 E-Article
format_del152 Buch
format_del189 Article, E-Article
format_dezi4 Article
format_dezwi2 Article, E-Article
format_finc Article, E-Article
format_nrw Article, E-Article
geogr_code not assigned
geogr_code_person not assigned
id ai-49-aHR0cDovL2R4LmRvaS5vcmcvMTAuMTE4Mi9ibG9vZC0yMDE4LTk5LTExOTA3MA
imprint American Society of Hematology, 2018
imprint_str_mv American Society of Hematology, 2018
institution DE-Pl11, DE-Rs1, DE-105, DE-14, DE-Ch1, DE-L229, DE-D275, DE-Bn3, DE-Brt1, DE-D161, DE-Zwi2, DE-Gla1, DE-Zi4, DE-15
issn 0006-4971, 1528-0020
issn_str_mv 0006-4971, 1528-0020
language English
last_indexed 2024-03-01T11:43:29.904Z
match_str weigel2018recurrentmutationsinegr2directspecificepigeneticreconfigurationinchroniclymphocyticleukemia
mega_collection American Society of Hematology (CrossRef)
physical 650-650
publishDate 2018
publishDateSort 2018
publisher American Society of Hematology
record_format ai
recordtype ai
series Blood
source_id 49
spelling Weigel, Christoph Assenov, Yassen Imbusch, Charles Wang, Qi Beekman, Renée Giacopelli, Brian Wu, Yue-zhong Brocks, David Dieter, Weichenhan Odilia, Popanda Schmezer, Peter Brors, Benedikt Mertens, Daniel Rippe, Karsten Rassenti, Laura Z. Kipps, Thomas J. Woyach, Jennifer A. Blachly, James S. Campo, Elias Zenz, Thorsten Byrd, John C. Martin-Subero, José I. Plass, Christoph Oakes, Christopher C. 0006-4971 1528-0020 American Society of Hematology Cell Biology Hematology Immunology Biochemistry http://dx.doi.org/10.1182/blood-2018-99-119070 <jats:title>Abstract</jats:title> <jats:p>Epigenetic alterations are universal in cancer and are important in establishing the malignant phenotype. Dissection of the factors that shape the tumor-specific epigenome may reveal insight into key aspects of tumorigenesis and therapeutic resistance. In chronic lymphocytic leukemia (CLL), we have previously found that broad changes in epigenetic patterns co-occur with the evolution of genetic alterations. We have also uncovered that aberrant patterning of DNA methylation in CLL involves excessive activity of a defined group of transcription factors (TFs), including the early growth response (EGR) TF family. Recent work has further revealed that recurrent mutations in EGR2 are associated with exceptionally poor clinical outcomes in CLL. The basis for the adverse association of EGR2 mutations in CLL is unclear.</jats:p> <jats:p>To explore the role of EGR2 mutations in CLL, we initially performed genome-wide DNA methylation analysis using Illumina arrays on CLL patients harboring EGR2 mutations (n=27) compared to EGR wild-type cases (n=265). We found that the three most common recurrent mutations, occurring at amino acid positions E356K, H384N and D411H within the DNA binding domain, are each associated with an exclusive subset of tumor-specific hypomethylated CpG sites. A search for TF sequence motifs at these loci revealed a strong enrichment of novel derivative EGR2 motifs that differ only marginally (usually by a single nucleotide) from the canonical EGR2 recognition sequence. Each recurrent mutation led to specific enrichment of a different derivative EGR2 motif. Furthermore, the canonical (wild-type) recognition sequence was not enriched, suggesting that mutations re-localize binding activity to derivate sequence motifs rather than simply altering binding affinity. Luciferase enhancer, proximity ligation and electrophoretic mobility shift assays confirmed that each EGR2 mutant protein specifically binds and enhances transcriptional activity only when the matched EGR2 derivative recognition motif is present. These results establish that derivative motif sequences may function as novel cryptic enhancers in the presence of the cognate EGR2 mutant TF.</jats:p> <jats:p>We performed multiomics profiling (DNA methylome, ATAC-seq, ChIP-seq and RNA-seq) to examine the nature of the epigenetic reconfiguration and the phenotypic impact of individual EGR2 mutations. Whole genome bisulfite sequencing of E356K- and H384N-mutated CLL samples (n=4 each) was used to reveal the full complement of recurrent differentially methylated regions (DMRs) across the genome, and recapitulated the mutually-exclusive pattern of DMRs between mutations. Overlaying DMRs with data from ChIP-seq and ATAC-seq experiments in the same samples revealed the nature of EGR2 mutation-specific chromatin reconfiguration to be remarkably mutation-specific. For E356K, hypomethylated DMRs are often associated with foci of accessible chromatin, EGR2 binding, and flanked by gains of H3K4me1 and H3K27ac, indicative of the acquisition of active enhancer function. Conversely, H384N mutations generated fewer DMRs and mainly directed the deposition of H3K4me1 only, indicative of gain of poised enhancers at these loci. RNA-sequencing analyses revealed that a subset of epigenetically reconfigured regions was associated with mutation-specific altered gene expression, and differences were virtually always associated with proximal gene activation. E356K and H384N mutations displayed highly differential gene expression patterns, with E356K exhibiting a greater impact on gene expression. Integrated analyses indicated that E356K mutations may specifically involve activated Notch signaling, revealed by the aberrant activation of Notch target genes and the mutual exclusivity of NOTCH1 mutations, further highlighted by enriched co-mutation of NOTCH1 in H384N-mutated CLL.</jats:p> <jats:p>Together these findings provide an exceptional example of the precise role that a singular TF may play in programming the epigenetic landscape. As there are no known TFs that naturally bind derivative EGR2 motifs, these mutant proteins provide insight into aberrant enhancer generation and the phenotypic impact of (re)directed TF binding in a human disease setting. Although these recurrent mutations are presently only known in CLL, these findings provide insight into the mechanisms that may surround other gain-of-function TF activity in various malignancies.</jats:p> <jats:sec> <jats:title>Disclosures</jats:title> <jats:p>Kipps: Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Verastem: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Consultancy, Honoraria, Research Funding; Genentech Inc: Consultancy, Research Funding; Pharmacyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy; F. Hoffmann-La Roche Ltd: Consultancy, Research Funding; Verastem: Membership on an entity's Board of Directors or advisory committees.</jats:p> </jats:sec> Recurrent Mutations in EGR2 Direct Specific Epigenetic Reconfiguration in Chronic Lymphocytic Leukemia Blood
spellingShingle Weigel, Christoph, Assenov, Yassen, Imbusch, Charles, Wang, Qi, Beekman, Renée, Giacopelli, Brian, Wu, Yue-zhong, Brocks, David, Dieter, Weichenhan, Odilia, Popanda, Schmezer, Peter, Brors, Benedikt, Mertens, Daniel, Rippe, Karsten, Rassenti, Laura Z., Kipps, Thomas J., Woyach, Jennifer A., Blachly, James S., Campo, Elias, Zenz, Thorsten, Byrd, John C., Martin-Subero, José I., Plass, Christoph, Oakes, Christopher C., Blood, Recurrent Mutations in EGR2 Direct Specific Epigenetic Reconfiguration in Chronic Lymphocytic Leukemia, Cell Biology, Hematology, Immunology, Biochemistry
title Recurrent Mutations in EGR2 Direct Specific Epigenetic Reconfiguration in Chronic Lymphocytic Leukemia
title_full Recurrent Mutations in EGR2 Direct Specific Epigenetic Reconfiguration in Chronic Lymphocytic Leukemia
title_fullStr Recurrent Mutations in EGR2 Direct Specific Epigenetic Reconfiguration in Chronic Lymphocytic Leukemia
title_full_unstemmed Recurrent Mutations in EGR2 Direct Specific Epigenetic Reconfiguration in Chronic Lymphocytic Leukemia
title_short Recurrent Mutations in EGR2 Direct Specific Epigenetic Reconfiguration in Chronic Lymphocytic Leukemia
title_sort recurrent mutations in egr2 direct specific epigenetic reconfiguration in chronic lymphocytic leukemia
title_unstemmed Recurrent Mutations in EGR2 Direct Specific Epigenetic Reconfiguration in Chronic Lymphocytic Leukemia
topic Cell Biology, Hematology, Immunology, Biochemistry
url http://dx.doi.org/10.1182/blood-2018-99-119070