Evolution of the Epigenetic Landscape in Childhood B Acute Lymphoblastic Leukemia and Its Role in Drug Resistance
Autor: | Elizabeth A. Raetz, Mignon L. Loh, Stephen P. Hunger, Xiaotu Ma, Sonali Narang, Christopher E. Mason, Nikki A. Evensen, Kylie M. Getz, Aristotelis Tsirigos, Jun H. Choi, Shella Saint Fleur-Lominy, Stephen Kelly, Gunjan Sethia, Cem Meydan, Richard C. Harvey, Jun J. Yang, Teena Bhatla, William L. Carroll, Patrick A. Brown, Cheryl L. Willman |
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Rok vydání: | 2020 |
Předmět: |
0301 basic medicine
Male Cancer Research Adolescent Biology Somatic evolution in cancer Article Epigenesis Genetic Clonal Evolution Histones 03 medical and health sciences 0302 clinical medicine Recurrence Precursor B-Cell Lymphoblastic Leukemia-Lymphoma Humans Epigenetics Child Promoter Regions Genetic Regulation of gene expression Gene Expression Regulation Leukemic Epigenome DNA Methylation Chromatin 030104 developmental biology Enhancer Elements Genetic Oncology Drug Resistance Neoplasm 030220 oncology & carcinogenesis Reduced representation bisulfite sequencing Child Preschool DNA methylation Cancer research Female Chromatin immunoprecipitation |
Zdroj: | Cancer Res |
ISSN: | 1538-7445 |
Popis: | Although B-cell acute lymphoblastic leukemia (B-ALL) is the most common malignancy in children and while highly curable, it remains a leading cause of cancer-related mortality. The outgrowth of tumor subclones carrying mutations in genes responsible for resistance to therapy has led to a Darwinian model of clonal selection. Previous work has indicated that alterations in the epigenome might contribute to clonal selection, yet the extent to which the chromatin state is altered under the selective pressures of therapy is unknown. To address this, we performed chromatin immunoprecipitation, gene expression analysis, and enhanced reduced representation bisulfite sequencing on a cohort of paired diagnosis and relapse samples from individual patients who all but one relapsed within 36 months of initial diagnosis. The chromatin state at diagnosis varied widely among patients, while the majority of peaks remained stable between diagnosis and relapse. Yet a significant fraction was either lost or newly gained, with some patients showing few differences and others showing massive changes of the epigenetic state. Evolution of the epigenome was associated with pathways previously linked to therapy resistance as well as novel candidate pathways through alterations in pyrimidine biosynthesis and downregulation of polycomb repressive complex 2 targets. Three novel, relapse-specific superenhancers were shared by a majority of patients including one associated with S100A8, the top upregulated gene seen at relapse in childhood B-ALL. Overall, our results support a role of the epigenome in clonal evolution and uncover new candidate pathways associated with relapse. Significance: This study suggests a major role for epigenetic mechanisms in driving clonal evolution in B-ALL and identifies novel pathways associated with drug resistance. |
Databáze: | OpenAIRE |
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