2. Academic Validation
  3. Drug addiction unveils a repressive methylation ceiling in EZH2-mutant lymphoma

Drug addiction unveils a repressive methylation ceiling in EZH2-mutant lymphoma

  • Nat Chem Biol. 2023 Mar 27. doi: 10.1038/s41589-023-01299-1.
Hui Si Kwok # 1 2,  Allyson M Freedy # 1 2,  Allison P Siegenfeld 1 2,  Julia W Morriss 1 2,  Amanda L Waterbury 1 2,  Stephen M Kissler 3,  Brian B Liau 4 5
Affiliations

Affiliations

  • 1 Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.
  • 2 Broad Institute of MIT and Harvard, Cambridge, MA, USA.
  • 3 Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
  • 4 Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA. [email protected].
  • 5 Broad Institute of MIT and Harvard, Cambridge, MA, USA. [email protected].
  • # Contributed equally.
PMID: 36973442 DOI: 10.1038/s41589-023-01299-1
Abstract

Drug addiction, a phenomenon where Cancer cells paradoxically depend on continuous drug treatment for survival, has uncovered cell signaling mechanisms and Cancer codependencies. Here we discover mutations that confer drug addiction to inhibitors of the transcriptional repressor polycomb repressive complex 2 (PRC2) in diffuse large B-cell lymphoma. Drug addiction is mediated by hypermorphic mutations in the CXC domain of the catalytic subunit EZH2, which maintain H3K27me3 levels even in the presence of PRC2 inhibitors. Discontinuation of inhibitor treatment leads to overspreading of H3K27me3, surpassing a repressive methylation ceiling compatible with lymphoma cell survival. Exploiting this vulnerability, we show that inhibition of SETD2 similarly induces the spread of H3K27me3 and blocks lymphoma growth. Collectively, our findings demonstrate that constraints on chromatin landscapes can yield biphasic dependencies in epigenetic signaling in Cancer cells. More broadly, we highlight how approaches to identify drug addiction mutations can be leveraged to discover Cancer vulnerabilities.

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