DNMT3A R882

When focusing on the 470 patients with 2022 ELN favorable-risk NPM1 mut AML, multivariable analysis for event-free survival (EFS) identified age (p < 0.001), DNMT3A R882 (p < 0.001), IDH1 (p = 0.007), and MRG mutations (p = 0.03) as unfavorable factors, cohesin gene co-mutations (p = 0.001) and treatment with gemtuzumab ozogamicin (p = 0.007) as favorable factors...For OS, age (p < 0.001), DNMT3A R882 (p = 0.042), IDH1 (p = 0.045), and KRAS (0.003) mutations were unfavorable factors, sole favorable factor was IDH2 co-mutation (p = 0.037). In 2022 ELN favorable-risk NPM1 mut AML, MRG mutations are associated with inferior EFS; however, this effect is no longer present when considering NPM1 mut MRD status post cycle 2; DNMT3A R882 and MYC mutations remained adverse, and cohesin gene mutations favorable prognostic factors independent of the NPM1 mut MRD status.

This epigenetic heterogeneity was associated with the transcriptional variability of developmental and membrane-associated factors shaping stem cell niche, and also was a predictor of the response of AML cells to hypomethylating agents, implying that the survival of AML cells depends on stochastic DNA methylations at bivalent domains. Altogether, our work provides a novel mechanistic model suggesting the genomic origin of the aberrant epigenomic heterogeneity in disease conditions.

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.

The patient achieved hematological CR on day 163 and remained in molecular CR 3 years after allo-HCT without adverse effects. Quizartinib combined with DLI may be a feasible treatment for early relapse of FLT3-ITD-positive AML after allo-HCT, even with concurrent DNMT3A and NPM1 mutations.

Longitudinal molecular analysis of 12 cases with biallelic DNMT3AMT demonstrated that such clones persisted or expanded in 9 relapsed or transformed cases (75%) suggesting the early origin of biallelic hits with strong leukemogenic potential. Our study describes the likelihood that biallelic DNMT3AMT, while rare, are indeed compatible with clonal expansion and thus questions the applicability of synthetic lethality strategies.

This study also reveals associations between germline genetic variants and incident CHIP. Our comprehensive longitudinal assessment yields insights into cell-intrinsic and -extrinsic factors contributing to the development and progression of CHIP clones in older adults.

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.

MOLM13 cells were exposed to stepwise increasing concentrations of cytarabine (Ara-C) to generate MOLM13/Ara-C cells...Furthermore, CALCRL knockdown restricted tumor growth and the chemoresistance of AML in vivo, as well as inducing cell apoptosis in tumor tissues. Together, these data reveal that CALCRL is a vital regulator of leukemia cell survival and resistance to chemotherapy, suggesting CALCRL as a promising therapeutic target for the treatment of FTL3-ITD and DNMT3A-R882 double-mutated AML.

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.

DNMT3A was mutated in 18% (2903/16,565) of all MN which included primary acute myeloid leukemia (pAML, n=1910), secondary (sAML, n=531), myeloproliferative neoplasms (MPN, n=100), myelodysplastic syndrome/myeloproliferative neoplasm (MDS/MPN, n=57), myelodysplastic syndrome (MDS, n=305) in the whole cohort. We analyzed 2903 DNMT3AMT MN and further classified them; 41%(n=1191/2903) had single R882, 48%(n=1407/2903) with single non-R882, 8%(n=226/2903) had double mutations at non-R882 locus, 1%(n=39/2903) was homozygous for R882 and 1% (n=40/2903) with mutations at R882 and non-R882 positions. Among non-R882 mutations, missense was more common [38%(85/226)] than nonsense [4%(9/226)], frameshift [1%(2/226)], and all others [57%(130/226)] (including splice-site, insertions, deletions, and other combinations in double non-R882 mutations).

Surprisingly, the clonal mutations were not well mixed in the BM with regions of high clonal diversity millimeters away from regions with a paucity of these mutated clones. Future work will expand this platform to describe BM clonal architecture in a larger set of bone marrow specimens and a wide variety clinical scenarios to help further explain the role of the BM niche in CH, MPNs and leukemia.