Influence of genetic co-mutation on chemotherapeutic outcome in NPM1-mutated and FLT3-ITD wild-type AML patients.

BACKGROUND: Nucleophosmin 1 (NPM1) gene-mutated acute myeloid leukemia (NPM1mut AML) is classified as a subtype with a favorable prognosis. However, some patients fail to achieve a complete remission or relapse after intensified chemotherapy. Genetic abnormalities in concomitant mutations contribute to heterogeneous prognosis of NPM1mut AML patients. METHODS: In this study, 91 NPM1-mutated and FLT3-ITD wild-type (NPM1mut/FLT3-ITDwt) AML patients with intermediate-risk karyotype were enrolled to analyze the impact of common genetic co-mutations on chemotherapeutic outcome. RESULTS: Our data revealed that TET1/2 (52/91, 57.1%) was the most prevalent co-mutation in NPM1mut AML patients, followed by IDH1/2 (36/91, 39.6%), DNMT3A (35/91, 38.5%), myelodysplastic syndrome related genes (MDS-related genes) (ASXL1, BCOR, EZH2, RUNX1, SF3B1, SRSF2, STAG2, U2AF1 and ZRSR2 genes) (35/91, 38.5%), FLT3-TKD (27/91, 29.7%) and GATA2 (13/91, 14.3%) mutations. Patients with TET1/2mut exhibited significantly worse relapse-free survival (RFS) (median, 28.7 vs. not reached (NR) months; p = 0.0382) compared to patients with TET1/2wt, while no significant difference was observed in overall survival (OS) (median, NR vs. NR; p = 0.3035). GATA2mut subtype was associated with inferior OS (median, 28 vs. NR months; p < 0.0010) and RFS (median, 24 vs. NR months; p = 0.0224) compared to GATA2wt. By multivariate analysis, GATA2mut and MDS-related genesmut were independently associated with worse survival. CONCLUSION: Mutations in TET1/2, GATA2 and MDS-related genes were found to significantly influence the chemotherapeutic outcome of patients with NPM1mut AML. The findings of our study have significant clinical implications for identifying patients who have an adverse response to frontline chemotherapy and provide a novel reference for further prognostic stratification of NPM1mut/FLT3-ITDwt AML patients.

Concomitant targeting of FLT3 and SPHK1 exerts synergistic cytotoxicity in FLT3-ITD+ acute myeloid leukemia by inhibiting ß-catenin activity via the PP2A-GSK3ß axis.

BACKGROUND: Approximately 25-30% of patients with acute myeloid leukemia (AML) have FMS-like receptor tyrosine kinase-3 (FLT3) mutations that contribute to disease progression and poor prognosis. Prolonged exposure to FLT3 tyrosine kinase inhibitors (TKIs) often results in limited clinical responses due to diverse compensatory survival signals. Therefore, there is an urgent need to elucidate the mechanisms underlying FLT3 TKI resistance. Dysregulated sphingolipid metabolism frequently contributes to cancer progression and a poor therapeutic response. However, its relationship with TKI sensitivity in FLT3-mutated AML remains unknown. Thus, we aimed to assess mechanisms of FLT3 TKI resistance in AML. METHODS: We performed lipidomics profiling, RNA-seq, qRT-PCR, and enzyme-linked immunosorbent assays to determine potential drivers of sorafenib resistance. FLT3 signaling was inhibited by sorafenib or quizartinib, and SPHK1 was inhibited by using an antagonist or via knockdown. Cell growth and apoptosis were assessed in FLT3-mutated and wild-type AML cell lines via Cell counting kit-8, PI staining, and Annexin-V/7AAD assays. Western blotting and immunofluorescence assays were employed to explore the underlying molecular mechanisms through rescue experiments using SPHK1 overexpression and exogenous S1P, as well as inhibitors of S1P2, ß-catenin, PP2A, and GSK3ß. Xenograft murine model, patient samples, and publicly available data were analyzed to corroborate our in vitro results. RESULTS: We demonstrate that long-term sorafenib treatment upregulates SPHK1/sphingosine-1-phosphate (S1P) signaling, which in turn positively modulates ß-catenin signaling to counteract TKI-mediated suppression of FLT3-mutated AML cells via the S1P2 receptor. Genetic or pharmacological inhibition of SPHK1 potently enhanced the TKI-mediated inhibition of proliferation and apoptosis induction in FLT3-mutated AML cells in vitro. SPHK1 knockdown enhanced sorafenib efficacy and improved survival of AML-xenografted mice. Mechanistically, targeting the SPHK1/S1P/S1P2 signaling synergizes with FLT3 TKIs to inhibit ß-catenin activity by activating the protein phosphatase 2 A (PP2A)-glycogen synthase kinase 3ß (GSK3ß) pathway. CONCLUSIONS: These findings establish the sphingolipid metabolic enzyme SPHK1 as a regulator of TKI sensitivity and suggest that combining SPHK1 inhibition with TKIs could be an effective approach for treating FLT3-mutated AML.

Impact of different CEBPA mutations on therapeutic outcome in acute myeloid leukemia.

Biallelic mutations of the CEBPA gene (CEBPAbi) are generally associated with favorable prognosis in patients with acute myeloid leukemia (AML). Monoallelic mutations of the CEBPA gene in carboxy-terminal DNA-binding region (CEBPAsmbZIP) and amino-terminal transactivation domains (CEBPAsmTAD) indicate distinct clinical characteristics and therapeutic outcomes. However, further investigation is required to fully understand these differences. In this retrospective study, we enrolled 77 AML patients with CEBPA mutations, including 53 with CEBPAbi, 12 with CEBPAsmbZIP and 12 with CEBPAsmTAD. The clinical characteristics of the three CEBPAmut groups presented significant differences in age, FAB classification, hemoglobin level and platelet count at diagnosis. The CEBPAsmTAD group exhibited shorter 2-year overall survival (OS) and relapse-free survival (RFS) compared to the CEBPAbi group and CEBPAsmbZIP group in AML patients. The most common co-mutations observed in CEBPAmut AML patients were TET2 and GATA2, which had no effect on prognosis. 2-year RFS of 27 CEBPAmut AML patients who underwent allo-HSCT was better than those who did not. MRD3 positive was identified as an influencing factor for 2-year OS and RFS. Allo-HSCT was found to improve the prognosis of CEPBAmut AML patients with positive MRD3 and adverse co-mutations.

Homoharringtonine may help improve the outcomes of venetoclax and azacitidine in AML1-ETO positive acute myeloid leukemia.

PURPOSE: T(8;21)(q22;q22.1)/AML1-ETO positive acute myeloid leukemia (AE-AML) is sensitive to conventional chemotherapy with a favorable prognosis. However, recent small case reports suggest the limited effectiveness of venetoclax (VEN) and hypomethylating agents (HMA) in treating AE-AML. The aim of this retrospective study was to evaluate the effectiveness of VEN plus AZA (VA) in AE-AML and explore whether adding homoharringtonine (HHT) to VA (VAH) could improve the response. METHODS: Patients who received VEN plus AZA and HHT (VAH) or VEN plus AZA (VA) regimens were included in this retrospective study. The endpoints of this study were to evaluate the rate of composite complete remission (CRc), measurable residual disease (MRD), event-free survival (EFS), overall survival (OS), and relapse between VAH and VA groups. RESULTS: A total of 32 AE-AML patients who underwent VA or VAH treatments (newly diagnosed with VA, ND-VA, n = 8; relapsed/refractory with VA, R/R-VA, n = 10; relapsed/refractory with VAH, R/R-VAH, n = 14) were included. The CR (complete remission) /CRi (CR with incomplete count recovery) rate of ND-VA, R/R-VA and R/R-VAH were 25%, 10%, and 64.3%, respectively. Measurable residual disease (MRD) negative was observed in 66.7% of R/R-VAH and none of VA-R/R patients. Co-occurring methylation mutations are associated with poor outcomes with VA but exhibit a more favorable response with VAH treatment. Additionally, patients with c-kit mutation presented inferior outcomes with both VEN-based regimens. All regimens were tolerated well by all patients. CONCLUSION: Our data confirmed the poor response of VA in AE-AML, whether used as frontline or salvage therapy. Adding HHT to VA may improve outcomes and enhance the efficacy of VEN in this population.

Changing epidemiology, microbiology and mortality of bloodstream infections in patients with haematological malignancies before and during SARS-CoV-2 pandemic: a retrospective cohort study.

OBJECTIVE: This study was to explore the changes in bacterial bloodstream infection (BSI) in patients with haematological malignancies (HMs) before and during SARS-CoV-2 pandemic. DESIGN: Retrospective cohort study between 2018 and 2021. SETTING: The largest haematological centre in southern China. RESULTS: A total of 599 episodes of BSI occurring in 22 717 inpatients from January 2018 to December 2021 were analysed. The frequencies of the total, Gram-negative and Gram-positive BSI before and during the pandemic were 2.90% versus 2.35% (p=0.011), 2.49% versus 1.77% (p<0.001) and 0.27% versus 0.44% (p=0.027), respectively. The main isolates from Gram-negative or Gram-positive BSI and susceptibility profiles also changed. The 30-day mortality caused by BSI was lower during the pandemic (21.1% vs 14.3%, p=0.043). Multivariate analysis revealed that disease status, pulmonary infection and shock were independent predictors of 30-day mortality. CONCLUSION: Our data showed that the incidence of total and Gram-negative organisms BSI decreased, but Gram-positive BSI incidence increased in patients with HMs during the pandemic along with the changes of main isolates and susceptibility profiles. Although the 30-day mortality due to BSI was lower during the pandemic, the new infection prevention strategy should be considered for any future pandemics.