Autophagy has been associated with oncogenesis with one of its emerging key functions being its contribution to the metabolism of tumors. Therefore, deciphering the mechanisms of how autophagy supports tumor cell metabolism is essential. Here, we demonstrate that the inhibition of autophagy induces an accumulation of lipid droplets (LD) due to a decrease in fatty acid β-oxidation, that leads to a reduction of oxidative phosphorylation (OxPHOS) in acute myeloid leukemia (AML), but not in normal cells. Thus, the autophagic process participates in lipid catabolism that supports OxPHOS in AML cells. Interestingly, the inhibition of OxPHOS leads to LD accumulation with the concomitant inhibition of autophagy. Mechanistically, we show that the disruption of mitochondria–endoplasmic reticulum (ER) contact sites (MERCs) phenocopies OxPHOS inhibition. Altogether, our data establish that mitochondria, through the regulation of MERCs, controls autophagy that, in turn finely tunes lipid degradation to fuel OxPHOS supporting proliferation and growth in leukemia.

CPX-351 is a liposomal formulation of cytarabine and daunorubicin approved for the treatment of adults with newly diagnosed, therapy-related acute myeloid leukemia (t-AML) or AML with myelodysplasia-related changes (MRC-AML). We retrospectively analyzed the efficacy and safety of CPX-351 in a real-world setting in 103 patients from 12 French centers, including the evaluation of molecular abnormalities at baseline and minimal residual disease (MRD) in responding patients, compared with a historical data set from Bordeaux-Toulouse DATAML registry. A favorable safety profile was observed, with a low frequency of alopecia (11%) and gastrointestinal toxicity (50%). The overall response rate after induction was 59%, and MRD <10−3 was achieved in 57% of complete response (CR)/CR with incomplete hematological recovery (CRi) patients. Only the presence of mutated TP53 (P = .02) or PTPN11 (P = .004) predicted lower response in multivariate analysis. Interestingly, high-risk molecular prognosis subgroups defined by 2017 European LeukemiaNet risk stratification, including ASXL1 and RUNX1 mutations, were not associated with a significantly lower response rate using CPX-351. With a median follow-up of 8.6 months, median overall survival (OS) was 16.1 months. Thirty-six patients underwent allogeneic stem cell transplantation with a significantly longer median OS compared with nontransplanted patients (P < .001). In multivariate analyses, only spliceosome mutations were associated with better OS (P = .04). In comparison with intensive chemotherapy, there was no difference in OS for patients <60 years. These data confirm the efficacy and safety of CPX-351 in high-risk AML (t-AML and MRC-AML) in a real-life setting. CPX-351 is a treatment of choice for patients aged ≥60 years.

Acute myeloid leukemia (AML) intensive chemotherapy combined with broad-spectrum antibiotics, leads to gut microbiota dysbiosis promoting pathological conditions and an increased incidence of complications. Here we report findings from a phase II single-arm, multicenter study evaluating autologous fecal microbiota transfer (AFMT) in 25 AML patients treated with intensive chemotherapy and antibiotics (ClinicalTrials.gov number: NCT02928523). The co-primary outcomes of the study are to evaluate the efficacy of AFMT in dysbiosis correction and multidrug-resistant bacteria eradication. The main secondary outcomes are to define a dysbiosis biosignature, to evaluate the effect of dysbiosis correction on patient clinical status, to assess the short and mid-term safety of AFMT in this immunocompromised population, and to evaluate the feasibility of the AFMT procedure and acceptability by the patient. Intensive induction chemotherapy induces a dramatic decrease of α-diversity indices, and a microbial dysbiosis with a significant shift of the microbial communities and domination of pro-inflammatory families. After AFMT treatment, α-diversity indices return to their initial mean levels and the similarity index shows the restoration of microbial communities. The trial meets pre-specified endpoints. AFMT appears to be safe and may be effective for gut microbiota restoration in AML patients receiving intensive chemotherapy and antibiotics, with an excellent gut microbiota reconstruction based on both richness and diversity indices at the species level.

Although transcription factor CCAAT-enhancer binding protein α (C/EBPα) is critical for normal and leukemic differentiation, its role in cell and metabolic homeostasis is largely unknown in cancer. Here, multiomics analyses uncovered a coordinated activation of C/EBPα and Fms-like tyrosine kinase 3 (FLT3) that increased lipid anabolism in vivo and in patients with FLT3-mutant acute myeloid leukemia (AML). Mechanistically, C/EBPα regulated the fatty acid synthase (FASN)–stearoyl-CoA desaturase (SCD) axis to promote fatty acid (FA) biosynthesis and desaturation. We further demonstrated that FLT3 or C/EBPα inactivation decreased monounsaturated FA incorporation to membrane phospholipids through SCD downregulation. Consequently, SCD inhibition enhanced susceptibility to lipid redox stress that was exploited by combining FLT3 and glutathione peroxidase 4 inhibition to trigger lipid oxidative stress, enhancing ferroptotic death of FLT3-mutant AML cells. Altogether, our study reveals a C/EBPα function in lipid homeostasis and adaptation to redox stress, and a previously unreported vulnerability of FLT3-mutant AML to ferroptosis with promising therapeutic application. Significance: FLT3 mutations are found in 30% of AML cases and are actionable by tyrosine kinase inhibitors. Here, we discovered that C/EBPα regulates FA biosynthesis and protection from lipid redox stress downstream mutant-FLT3 signaling, which confers a vulnerability to ferroptosis upon FLT3 inhibition with therapeutic potential in AML. This article is highlighted in the In This Issue feature, p. 1501

The outcome of acute myeloid leukemia patients aged 70 years or older is poor. Defining the best treatment option remains controversial especially when choosing between intensive chemotherapy and hypomethylating agents. We set up a multicentric European database collecting data of 3 700 newly diagnosed acute myeloid leukemia patients ≥70 years. The primary objective was to compare overall survival in patients selected for intensive chemotherapy (n = 1199) or hypomethylating agents (n = 1073). With a median follow-up of 49.5 months, the median overall survival was 10.9 (95% CI: 9.7–11.6) and 9.2 months (95% CI: 8.3–10.2) with chemotherapy and hypomethylating agents, respectively. Complete remission or complete remission with incomplete hematologic recovery was 56.1% and 19.7% with chemotherapy and hypomethylating agents, respectively (P < 0.0001). Treatment effect on overall survival was time-dependent. The Royston and Parmar model showed that patients treated with hypomethylating agents had a significantly lower risk of death before 1.5 months of follow-up; no significant difference between 1.5 and 4.0 months, whereas patients treated with intensive chemotherapy had a significantly better overall survival from four months after start of therapy. This study shows that intensive chemotherapy remains a valuable option associated with a better long-term survival in older AML patients.

NPM 1-mutated acute myeloid leukemia (AML) shows unique features. However, the characteristics of “therapy-related” NPM1-mutated AML (t-NPM1 AML) are poorly understood. We compared the genetics, transcriptional profile, and clinical outcomes of t-NPM1 AML, de novo NPM1-mutated AML (dn-NPM1 AML), and therapy-related AML (t-AML) with wild-type NPM1 (t-AML). Normal karyotype was more frequent in t-NPM1 AML (n = 78/96, 88%) and dn-NPM1 (n = 1986/2394, 88%) than in t-AML (n = 103/390, 28%; P < .001). DNMT3A and TET2 were mutated in 43% and 40% of t-NPM1 AML (n = 107), similar to dn-NPM1 (n = 88, 48% and 30%; P > 0.1), but more frequently than t-AML (n = 162; 14% and 10%; P < 0.001). Often mutated in t-AML, TP53 and PPM1D were wild-type in 97% and 96% of t-NPM1 AML, respectively. t-NPM1 and dn-NPM1 AML were transcriptionally similar, (including HOX genes upregulation). At 62 months of median follow-up, the 3-year overall survival (OS) for t-NPM1 AML (n = 96), dn-NPM1 AML (n = 2394), and t-AML (n = 390) were 54%, 60%, and 31%, respectively. In multivariable analysis, OS was similar for the NPM1-mutated groups (hazard ratio [HR] 0.9; 95% confidence interval [CI], 0.65-1.25; P = .45), but better in t-NPM1 AML than in t-AML (HR, 1.86; 95% CI, 1.30-2.68; P < .001). Relapse-free survival was similar between t-NPM1 and dn-NPM1 AML (HR, 1.02; 95% CI, 0.72-1.467; P = .90), but significantly higher in t-NPM1 AML versus t-AML (HR, 1.77; 95% CI, 1.19-2.64; P = .0045). t-NPM1 and dn-NPM1 AML have overlapping features, suggesting that they should be classified as a single disease entity.