Mutational analysis of DNMT3A improves the prognostic stratification of patients with acute myeloid leukemia

DNMT3A-R882: a mutation with many paradoxes

Understanding the underlying mechanism of acute myeloid leukemia (AML) has led to the discovery of novel biomarkers to help predict, treat and monitor leukemia. DNA (cytosine-5)-methyltransferase 3 A (DNMT3A) is considered a prognostic and therapeutic epigenetic target in AML patients with a hotspot mutation of R882. R882 mutation is associated with impaired differentiation of Hematopoietic stem cells in the bone marrow and disease progression. The prevalence of R882 mutation varied in different ethnicities and countries, and similarly, its prognostic impact differed among numerous studies. Nevertheless, the co-occurrence of mutations in R882 with NPM1 and FLT3 has been reported more frequently and is associated with a worse prognosis. These studies also suggest diverse results regarding bone marrow transplantation response as a treatment, while chemoresistance is reached as a conclusive outcome These findings highlight the crucial need for an in-depth discussion on the significance of the R882 mutation in AML patients. Understanding its impact on leukemic transformation, prognosis, and treatment is vital for advancing clinical implications.

XPO1 inhibition displays anti-leukemia efficacy against DNMT3A-mutant acute myeloid leukemia via downregulating glutathione pathway

Acute myeloid leukemia (AML) patients with DNA methyltransferase 3A (DNMT3A) mutation display poor prognosis, and targeted therapy is not available currently. Our previous study identified increased expression of Exportin1 (XPO1) in DNMT3AR882H AML patients. Therefore, we further investigated the therapeutic effect of XPO1 inhibition on DNMT3AR882H AML. Three types of DNMT3AR882H AML cell lines were generated, and XPO1 was significantly upregulated in all DNMT3AR882H cells compared with the wild-type (WT) cells. The XPO1 inhibitor selinexor displayed higher potential in the inhibition of proliferation, promotion of apoptosis, and blockage of the cell cycle in DNMT3AR882H cells than WT cells. Selinexor also significantly inhibited the proliferation of subcutaneous tumors in DNMT3AR882H AML model mice. Primary cells with DNMT3A mutations were more sensitive to selinexor in chemotherapy-naive AML patients. RNA sequencing of selinexor treated AML cells revealed that the majority of metabolic pathways were downregulated after selinexor treatment, with the most significant change in the glutathione metabolic pathway. Glutathione inhibitor L-Buthionine-(S, R)-sulfoximine (BSO) significantly enhanced the apoptosis-inducing effect of selinexor in DNMT3AWT/DNMT3AR882H AML cells. 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.

A nomogram based on clinical features and molecular abnormalities for predicting the prognosis of patients with acute myeloid leukemia

Background

The high clinical and molecular heterogeneity of acute myeloid leukemia (AML) has led to an unsatisfactory clinical prognosis, thus we sought to incorporate both clinical features and molecular abnormalities to construct a new prognostic model.

Methods

A database search of the Gene Expression Omnibus (GEO) revealed 238 cases of adult AML. The independent risk factors were assessed using both univariate and multivariate Cox regression, as well as least absolute shrinkage and selection operator (LASSO) regression. The predictive accuracy, discriminatory power and clinical applicability of the nomogram were determined by the consistency index (C-index), calibration curves and decision curve analysis (DCA). In addition, a single-centre cohort of 135 cases was used for external validation.

Results

Multivariate Cox regression analysis showed that the independent influences on overall survival (OS) were age, type of disease, DNMT3A, IDH2 and TP53 mutations. The area under the curve (AUC) values for the training set were 0.755, 0.745 and 0.757 at 1, 2 and 3 years respectively; the AUC for the validation set were 0.648, 0.648 and 0.654 at 1, 2 and 3 years; and the AUC for the northwest China set were 0.692, 0.724 and 0.689 at 1, 2 and 3 years. The calibration and DCA indicated good consistency and clinical utility of the nomogram. Finally, younger (age <60 years) and elderly (age ≥60 years) patients were each divided into two risk groups with significantly different survival rates.

Conclusions

A nomogram consisting of five risk factors was developed for forecasting the prognosis of AML with guaranteed reliability.

Analysis of the clinical characteristics and prognosis of adult de novo acute myeloid leukemia (none APL) with PTPN11 mutations

We discuss the clinical characteristics and prognostic significance of adult individuals with PTPN11 mutations who have developed acute myeloid leukemia (AML) (none acute promyelocytic leukemia). Next generation sequencing and Sanger sequencing were used to detect 51 gene mutations, and multiplex-PCR was used to detect 41 fusion genes from 232 de novo adult AML patients retrospectively. About 7.76% patients harbored PTPN11 mutations, 20 PTPN11 alterations were identified, all of which were missense mutations in the N-SH2 (n = 16) and PTP (n = 4) domains located in exon 3. Patients with PTPN11 mut had significantly higher platelet counts and hemoglobin levels (p < 0.001), which were mainly detected in M5 (n = 12, 66.67%, p < 0.001) subtype. Patients with MLL-AF6 positive showed a higher frequency of PTPN11 mut (p = 0.018) in the 118 AML cases. PTPN11 mut were accompanied by other mutations, which were NPM1 (44.44%), DNMT3A (38.89%), FLT3 (38.89%), and NRAS (17.2%). PTPN11 mut had a negative impact on the complete remission rate in M5 subtype patients (p < 0.001). However, no statistically significant effect on overall survival (OS) with PTPN11 mut patients in the whole cohort and age group (p > 0.05) was observed. Further analysis revealed no significant difference in OS among NPM1 mut/PTPN11 mut, NPM1 mut/PTPN11 wt, DNMT3A mut/PTPN11 mut, and DNMT3A mut/PTPN11 wt patients (p > 0.05). Multivariate analysis showed the proportion of bone marrow blasts ≥65.4% was a factor significantly affecting OS in PTPN11 mut patients (p = 0.043).

Genetic, Phenotypic, and Clinical Heterogeneity of NPM1-Mutant Acute Myeloid Leukemias

The current classification of acute myeloid leukemia (AML) relies largely on genomic alterations. AML with mutated nucleophosmin 1 (NPM1-mut) is the largest of the genetically defined groups, involving about 30% of adult AMLs and is currently recognized as a distinct entity in the actual AML classifications. NPM1-mut AML usually occurs in de novo AML and is associated predominantly with a normal karyotype and relatively favorable prognosis. However, NPM1-mut AMLs are genetically, transcriptionally, and phenotypically heterogeneous. Furthermore, NPM1-mut is a clinically heterogenous group. Recent studies have in part clarified the consistent heterogeneities of these AMLs and have strongly supported the need for an additional stratification aiming to improve the therapeutic response of the different subgroups of NPM1-mut AML patients.