DNMT3A R882H

Taken together, DNMT3AR882 mutations are initially necessary for AML initiation, but are largely dispensable for disease maintenance. The notion that initiating oncogenes differ from those that maintain cancer has important implications for cancer evolution and therapy.

Our biochemical, cellular, and genomic DNA methylation analyses demonstrate that introducing the DNMT3B-converting mutations inhibits the R882H-/R882C-triggered DNMT3A polymerization and enhances substrate access, thereby eliminating the dominant-negative effect of the DNMT3A R882 mutations in cells. Together, this study provides mechanistic insights into DNMT3A R882 mutations-triggered aberrant oligomerization and DNA hypomethylation in AML, with important implications in cancer therapy.

In conclusion, our work reveals that selinexor displays anti-leukemia efficacy against DNMT3AR882H AML via downregulating glutathione pathway. Combination of selinexor and BSO provides novel therapeutic strategy for AML treatment.

Overexpression of DNMT3L (which is minimally expressed in AML cells) also corrects the hypomethylation phenotype of Dnmt3a marrow, probably by augmenting the activity of WT DNMT3A encoded by the residual WT allele. DNMT3L reactivation may represent a previously unidentified approach for restoring DNMT3A activity in hematopoietic cells with reduced DNMT3A function.

In Cox proportional hazards models controlling for basic demographics (N = 451K) or demographics plus cardiovascular-relevant covariates (N = 390K), we found that R882H but not R882C was associated with significantly greater incidence of heart failure and of a composite measure consisting of death or coronary artery disease (Figure 1B). In conclusion, our study found evidence in experimental models and patient data that DNMT3A R882H may pose a greater risk for inflammatory phenotypes than R882C.

In summary, our work demonstrates a novel CRISPR/Cas9 approach to dissect the contribution of individual somatic lesions in human leukemia. The precise correction of single lesions while leaving co-occurring mutations intact allows us to perform controlled, functional genetic experiments on primary human AML. Here, we employ this approach to dissect the contribution of DNMT3A mutations to leukemia initiation and maintenance.

DNMT3A mutations promote resistance to anthracyclines (including daunorubicin, the component of standard "7+3" induction therapy), interferon alpha, and ABL1 kinase inhibitor imatinib...The combination of Polθis + quizartinib and Polθis + etoposide completely eradicated clonogenic activity of these cells while Polθis + cytarabine and Polθis + azacytidine exerted modest and weak effects, respectively, when compared to individual compound treatments...Median survival time of the mice will be recorded. Altogether, we discovered that Polθ protects OTK-positive DNMT3A-deficient myeloid malignant cells from the toxic effects of DSBs and identified Polθ as a novel therapeutic target.

Notably, these mutations are still activating in the context of a heterozygous R882H mutation. Altogether, we showcase the utility of base editor scanning for discovering functional regions of target proteins.

There is a great diversity of possible genetic alterations in DNMT3A, TET2, and ASXL1 genes, which requires detailed investigation. Further studies in dynamics will evaluate their prognostic impacts in AML patients.

Taken together, our data showed that DNMT3A mutation caused NAMPT overexpression to induce the reprogramming of NAM-NAD metabolism and contribute to abnormal proliferation, which provided a potential direction for targeted therapy at the metabolic level in AML with DNMT3A mutation.