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Published on: June 13, 2019
A novel screening strategy to identify histone methyltransferase inhibitors reveals a crosstalk between DOT1L and
Yang Si1, Corentin Bon1,2, Magdalena Barbachowska1,2
1Epigenetic Chemical Biology, Department of Structural Biology and Chemistry, Institut Pasteur, UMR3523 CNRS 75015 Paris France paola.arimondo@cnrs.fr.
Abstract:
Epigenetic regulation is a dynamic and reversible process that controls gene expression. Abnormal function results in human diseases such as cancer, thus the enzymes that establish epigenetic marks, such as histone methyltransferases (HMTs), are potentially therapeutic targets. Noteworthily, HMTs form multiprotein complexes that in concert regulate gene expression. To probe epigenetic protein complexes regulation in cells, we developed a reliable chemical biology high-content imaging strategy to screen compound libraries simultaneously on multiple histone marks inside cells. By this approach, we identified that compound 4, a published CARM1 inhibitor, inhibits both histone mark H3R2me2a, regulated also by CARM1, and H3K79me2, regulated only by DOT1L, pointing out a crosstalk between CARM1 and DOT1L. Based on this interaction, we combined compound 4 and DOT1L inhibitor EPZ-5676 resulting in a stronger inhibition of cell proliferation and increase in apoptosis, indicating that our approach identifies possible effective synergistic drug combinations.
Insights
This study developed a new imaging method to screen epigenetic drugs. It revealed a link between CARM1 and DOT1L enzymes, leading to a combination therapy that effectively inhibits cancer cell growth.
Area of Science:
- Biochemistry
- Molecular Biology
- Chemical Biology
Background:
- Epigenetic regulation controls gene expression and is crucial for cellular function.
- Dysregulation of epigenetic marks is implicated in human diseases, particularly cancer.
- Histone methyltransferases (HMTs) are key enzymes in epigenetic regulation and represent potential therapeutic targets.
Purpose of the Study:
- To develop a high-content imaging strategy for probing epigenetic protein complex regulation.
- To screen compound libraries for inhibitors affecting multiple histone marks simultaneously.
- To identify novel therapeutic targets and synergistic drug combinations for cancer treatment.
Main Methods:
- Development of a chemical biology high-content imaging assay.
- Screening of compound libraries to identify inhibitors of HMTs.
- Simultaneous assessment of multiple histone marks (H3R2me2a and H3K79me2) within cells.
- Combination treatment with CARM1 inhibitor (compound 4) and DOT1L inhibitor (EPZ-5676).
Main Results:
- Identification of compound 4 as an inhibitor of both CARM1 and DOT1L-regulated histone marks.
- Discovery of a functional crosstalk between CARM1 and DOT1L in epigenetic regulation.
- Demonstration of synergistic effects of combined compound 4 and EPZ-5676 on inhibiting cell proliferation and inducing apoptosis.
Conclusions:
- The developed imaging strategy is effective for screening epigenetic regulators and identifying drug interactions.
- The identified crosstalk between CARM1 and DOT1L offers a novel therapeutic avenue.
- Combined inhibition of CARM1 and DOT1L shows promise as a synergistic anti-cancer strategy.
