DNMT3B Controls Enhancer-Linked Chromatin and Cell Cycle Networks in Acute Myeloid Leukemia

Area of Science:

• Oncology
• Epigenetics
• Molecular Biology

Background:

• DNMT3B is overexpressed in acute myeloid leukemia (AML) and linked to poor prognosis.
• Unlike DNMT3A, DNMT3B mutations are rare, suggesting epigenetic dysregulation.
• The precise role and impact of DNMT3B overexpression in AML are not fully understood.

Purpose of the Study:

• Investigate the epigenetic mechanisms and downstream effects of DNMT3B overexpression in AML.
• Utilize Nanaomycin A (NanA) as a probe to study DNMT3B's function.
• Explore DNMT3B's role in regulating cell proliferation, apoptosis, and drug sensitivity.

Main Methods:

• Integrated analysis of BeatAML, TCGA, and BLUEPRINT cohorts.
• Multi-omic profiling including RNA-seq, DNA methylation, ATAC-seq, and proteomics.
• Functional studies using Nanaomycin A (NanA) to perturb DNMT3B activity in AML models.

Main Results:

• DNMT3B overexpression correlates with enhancer-associated chromatin activation, especially in CEBPA- and NPM1-mutant AML.
• Nanaomycin A induced significant epigenomic remodeling, altering chromatin accessibility and DNA methylation.
• Perturbation of DNMT3B led to cell-cycle redistribution, increased apoptosis, and altered expression of apoptosis regulators (e.g., NOXA, PUMA, BCL2, MCL1).
• Combined DNMT3B inhibition and BCL2 inhibition showed synergistic cytotoxicity in DNMT3B-high AML.

Conclusions:

• DNMT3B acts as a context-dependent epigenetic regulator in AML, influencing chromatin organization, proliferation, and apoptotic resistance.
• DNMT3B-directed epigenetic modulation remodels regulatory networks and enhances sensitivity to venetoclax.
• DNMT3B-governed networks represent a potential co-targeting strategy for high-risk AML treatment.