Oncohistone Mutations Occur at Functional Sites of Regulatory ADP-Ribosylation
Recent studies have identified cancer-associated mutations in histone genes that lead to the expression of mutant versions of core histones called oncohistones. Many oncohistone mutations occur at Asp and Glu residues, two amino acids known to be ADP-ribosylated (ADPRylated) by PARP1. We screened 25...
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| Published in | Cancer research (Chicago, Ill.) Vol. 82; no. 13; pp. 2361 - 2377 |
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| Main Authors | , , , , , , , , , |
| Format | Journal Article |
| Language | English |
| Published |
United States
05.07.2022
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| Subjects | |
| Online Access | Get full text |
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| Summary: | Recent studies have identified cancer-associated mutations in histone genes that lead to the expression of mutant versions of core histones called oncohistones. Many oncohistone mutations occur at Asp and Glu residues, two amino acids known to be ADP-ribosylated (ADPRylated) by PARP1. We screened 25 Glu or Asp oncohistone mutants for their effects on cell growth in breast and ovarian cancer cells. Ectopic expression of six mutants of three different core histones (H2B, H3, and H4) altered cell growth in at least two different cell lines. Two of these sites, H2B-D51 and H4-D68, were indeed sites of ADPRylation in wild-type (unmutated) histones, and mutation of these sites inhibited ADPRylation. Mutation of H2B-D51 dramatically altered chromatin accessibility at enhancers and promoters, as well as gene expression outcomes, whereas mutation of H4-D68 did not. Additional biochemical, cellular, proteomic, and genomic analyses demonstrated that ADPRylation of H2B-D51 inhibits p300-mediated acetylation of H2B at many Lys residues. In breast cancer cell xenografts in mice, H2B-D51A promoted tumor growth, but did not confer resistance to the cytotoxic effects of PARP inhibition. Collectively, these results demonstrate that functional Asp and Glu ADPRylation sites on histones are mutated in cancers, allowing cancer cells to escape the growth-regulating effects of post-translational modifications via distinct mechanisms.
This study identifies cancer-driving mutations in histones as sites of PARP1-mediated ADP-ribosylation in breast and ovarian cancers, providing a molecular pathway by which cancers may subvert the growth-regulating effects of PARP1. |
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| Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 D.H. and W.L.K. conceived and developed this project. D.H. and W.L.K. designed the experiments and oversaw their execution, with input from L.A.B. D.H. performed most of the experiments and analyzed the data. C.V.C. assisted with the cell-based and biochemical assays, and performed the cell-derived xenograft assays with X.G. C.V.C. and S.M. performed the ChIP-qPCR assays. S.M. performed the ChIP-seq assays and histone protein purifications. A.N. analyzed the ChIP-seq and ATAC-seq data, and performed the integrative analysis of genomic datasets. R.S. analyzed the RNA-seq data. S.P.C. and C.V.C. performed the in vitro histone PTM assays with nucleosomes. A.D.E. performed the immunofluorescent staining assays in MDA-MB-468 cells. L.A.B. oversaw the execution of the ChIP-seq assay and histone protein purification, and contributed to the integration of genomic datasets. All authors contributed to the design and analysis of the experiments that they performed. D.H. prepared the initial drafts of the figures and text, which were edited by L.A.B. and W.L.K., and finalized by W.L.K. with input from the other authors. D.H., C.V.C., and W.L.K. revised the manuscript after review. W.L.K secured funding to support this project and provided intellectual support for all aspects of the work. Author Contributions |
| ISSN: | 0008-5472 1538-7445 |
| DOI: | 10.1158/0008-5472.CAN-22-0742 |