American Association for Cancer Research
00085472can183275-sup-210589_3_supp_5540854_ps0ljk.docx (179.3 kB)

Supplementary Methods from A Model System for Studying the DNMT3A Hotspot Mutation (DNMT3AR882) Demonstrates a Causal Relationship between Its Dominant-Negative Effect and Leukemogenesis

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journal contribution
posted on 2023-03-31, 02:40 authored by Rui Lu, Jun Wang, Zhihong Ren, Jiekai Yin, Yinsheng Wang, Ling Cai, Gang Greg Wang

This document includes sections of Supplementary Methods and Material, Supplementary Figures Legends and related references



Kimmel Scholar Award

North Carolina Biotech Center



Mutation of DNA methyltransferase 3A at arginine 882 (DNMT3AR882mut) is prevalent in hematologic cancers and disorders. Recently, DNMT3AR882mut has been shown to have hypomorphic, dominant-negative, and/or gain-of-function effects on DNA methylation under different biological contexts. However, the causal role for such a multifaceted effect of DNMT3AR882mut in leukemogenesis remains undetermined. Here, we report TF-1 leukemia cells as a robust system useful for modeling the DNMT3AR882mut-dependent transformation and for dissecting the cause–effect relationship between multifaceted activities of DNMT3AR882mut and leukemic transformation. Ectopic expression of DNMT3AR882mut and not wild-type DNMT3A promoted TF-1 cell transformation characterized by cytokine-independent growth, and induces CpG hypomethylation predominantly at enhancers. This effect was dose dependent, acted synergistically with the isocitrate dehydrogenase 1 (IDH1) mutation, and resembled what was seen in human leukemia patients carrying DNMT3AR882mut. The transformation- and hypomethylation-inducing capacities of DNMT3AR882mut relied on a motif involved in heterodimerization, whereas its various chromatin-binding domains were dispensable. Mutation of the heterodimerization motif that interferes with DNMT3AR882mut binding to endogenous wild-type DNMT proteins partially reversed the CpG hypomethylation phenotype caused by DNMT3AR882mut, thus supporting a dominant-negative mechanism in cells. In mice, bromodomain inhibition repressed gene-activation events downstream of DNMT3AR882mut-induced CpG hypomethylation, thereby suppressing leukemogenesis mediated by DNMT3AR882mut. Collectively, this study reports a model system useful for studying DNMT3AR882mut, shows a requirement of the dominant-negative effect by DNMT3AR882mut for leukemogenesis, and describes an attractive strategy for the treatment of leukemias carrying DNMT3AR882mut. These findings highlight a model system to study the functional impact of a hotspot mutation of DNMT3A at R882 in leukemia.

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