Targeting Metabolic Dependencies Fueling the TCA Cycle to Circumvent Therapy Resistance in Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is one of the most prevalent blood cancers, characterized by a dismal survival rate. This poor outcome is largely attributed to AML cells that persist despite treatment and eventually result in relapse. Relapse-initiating cells exhibit diverse resistance mechanisms, encompassing genetic factors and, more recently discovered, nongenetic factors such as metabolic adaptations. Leukemic stem cells (LSC) rely on mitochondrial metabolism for their survival, whereas hematopoietic stem cells primarily depend on glycolysis. Furthermore, following treatments such as cytarabine, a standard in AML treatment for over four decades, drug-persisting leukemic cells exhibit an enhanced reliance on mitochondrial metabolism. In this issue of Cancer Research, two studies investigated dependencies of AML cells on two respiratory substrates, α-ketoglutarate and lactate-derived pyruvate, that support mitochondrial oxidative phosphorylation (OXPHOS) following treatment with the imipridone ONC-213 and the BET inhibitor INCB054329, respectively. Targeting lactate utilization by interfering with monocarboxylate transporter 1 (MCT1 or SLC16A1) or lactate dehydrogenase effectively sensitized cells to BET inhibition in vitro and in vivo. In addition, ONC-213 affected αKGDH, a pivotal NADH-producing enzyme of the TCA cycle, to induce a mitochondrial stress response through ATF4 activation that diminished the expression of the antiapoptotic protein MCL1, consequently promoting apoptosis of AML cells. In summary, targeting these mitochondrial dependencies might be a promising strategy to kill therapy-naïve and treatment-resistant OXPHOS-reliant LSCs and to delay or prevent relapse. See related articles by Monteith et al., p. 1101 and Su et al., p. 1084.

Sweet syndrome induced by FLT3 inhibitors: case report and literature review.

BACKGROUND: Acute febrile neutrophilic dermatosis, also commonly referred to as Sweet syndrome, is often associated with tumors, infections, immune disorders and medications. FLT3 inhibitor-induced Sweet syndrome is a rare complication. METHODS AND RESULTS: We report a patient with relapsed and refractory acute monocytic leukemia harboring high-frequency FLT3-ITD and DNMT3a mutations. The FLT3 inhibitor gilteritinib was administered for reinduction therapy after failure of chemotherapy with a combination of venetoclax, decitabine, aclarubicin, cytarabine and granulocyte colony-stimulating factor. The leukemia patient achieved remission after 1 month of treatment. However, Sweet syndrome induced by gilteritinib, which was confirmed by skin biopsy, developed during induction therapy. Similar cases of Sweet syndrome following FLT3 inhibitor therapy for acute myeloid leukemia were reviewed. CONCLUSION: Attention should be given to this rare complication when FLT3 inhibitors are used for acute myeloid leukemia therapy, and appropriate treatments need to be administered in a timely manner.

Rapid progression from MDS to AML with gastric submucosal tumour as an extramedullary infiltration.

We present a rare case of myeloid sarcoma in the stomach of an elderly woman initially diagnosed with anaemia. Myeloid sarcoma, an unusual extramedullary manifestation of acute myeloid leukaemia (AML), primarily affects lymph nodes, bones, spine and skin, with gastrointestinal involvement being infrequent. Despite normal results from the initial endoscopy, a follow-up examination after 4 months revealed multiple submucosal gastric tumours. These developments coincided with worsening of anaemia and an increase in peripheral myeloblasts. Pathological evaluation and immunohistochemical staining confirmed gastric extramedullary infiltration associated with AML. This case highlights the importance of comprehensive diagnostic processes when suspecting leukaemic transformations, especially in myelodysplastic syndrome (MDS). Due to financial constraints, additional critical studies such as cytogenetics and next-generation sequencing were not performed. Nonetheless, this rare case demonstrates the visual observation of rapid progression from MDS to AML and concurrent early myeloid sarcoma development in an elderly patient.

[Safety and efficacy of 7-day administration of azacitidine and venetoclax combination therapy (7+7 therapy)].

Acute myelogenous leukemia (AML) has a poor prognosis in patients who are ineligible for intensive chemotherapy. The combination of azacitidine and venetoclax has been shown to have high overall efficiency and remission rates, even in patients ineligible for aggressive chemotherapy. However, myelosuppression is often prolonged after treatment, and infection can also occur. Severe myelosuppression is often addressed by dose titration, but specific dose titration methods have not been clarified. We used the standard induction therapy with azacitidine plus venetoclax, and if blasts decreased to 20% or less, switched to 7+7 therapy to shorten venetoclax to 7 days starting from the next cycle. In the 19 patients we treated (median age 80 years), response rate above MLFS was 100%, CR 57.9%, CRc (CR+CRi) 78.8%, median OS 693 days, median PFS 458 days, and median OS was not reached in previously untreated patients. This indicates that 7+7 is a highly effective and well-tolerated treatment.

[Fulminant Clostridioides difficile infection during treatment with FLT3 inhibitor for acute myeloid leukemia].

An 80-year-old man with FLT3-TKD mutation-positive acute myeloid leukemia (AML) relapsed during consolidation therapy with venetoclax/azacitidine and was started on gilteritinib as salvage therapy. On the day after treatment initiation, febrile neutropenia was observed, but the fever resolved promptly after initiation of antimicrobial therapy. On the fifth day after completion of antimicrobial therapy, the patient experienced fever and watery diarrhea over 10 times a day, and a diagnosis of Clostridioides difficile infection (CDI) was made based on stool examination. The patient was treated with intravenous metronidazole, but renal dysfunction, hypotension, and hypoxemia developed, and a CT scan showed pleural and intraperitoneal effusion, significant intestinal wall thickening, and intestinal dilatation. Fidaxomicin was started under general monitoring in the intensive care unit and response was achieved. The patient was discharged from the intensive care unit on the 18th day after the onset of CDI. We report this case not only due to the rarity of fulminant CDI during AML treatment, but also because it is a valuable example of effective treatment of fulminant CDI with fidaxomicin.

Impact of MLL::AF9 Gene Rearrangement on Survival of Acute Myeloid Leukaemia Patients: An Insight into Pakistani Population.

OBJECTIVE: To ascertain the frequency of the MLL::AF9 gene rearrangement and its association with survival in Pakistani patients suffering from acute myeloid leukaemia (AML). STUDY DESIGN: Analytical study. Place and Duration of the Study: Department of Haematology, National Institute of Blood Diseases and Bone Marrow Transplantation, Karachi, Pakistan, from 2015 to 2020. METHODOLOGY: Patients without a history of past AML chemotherapy, aged from 10 to 75 years, were included. Individuals with metastatic cancer, chronic myeloid leukaemia, or other haematological conditions were excluded. Identifying the MLL::AF9 gene involved RNA extraction, cDNA synthesis, and Real-time PCR amplification. The Chi-square test was used to examine the relationship between survival and the MLL::AF9 mutation. A Welch two-sample t-test was used to evaluate survival days depending on the MLL::AF9 gene rearrangement, while ANOVA was used to analyse survival days across various death statuses. RESULTS: The mean age of 130 patients was 36.65 ± 13.01 years, with 64.62% being males. The most common leukaemia type was AML-M2 (n = 32, 24.62%). During the study follow-up, 22.31% were still alive, 40.77% died, and the status of 36.92% were unknown. MLL::AF9 gene rearrangement was present in 11.54%. The group with MLL::AF9 gene rearrangement had significantly longer mean 'survival days' (1,542.33 ± 926.07) compared to the group without the gene rearrangement (206.42 ± 359.57, p <0.001). CONCLUSION: MLL-AF9 mutation was present in 11.54%. Age and MLL::AF9 gene rearrangement were significant predictors of survival in leukaemia patients. KEY WORDS: Acute myeloid leukaemia, MLL::AF9, Gene rearrangement, Survival.

Combining CRISPR-Cas9 and TCR exchange to generate a safe and efficient cord blood-derived T cell product for pediatric relapsed AML.

BACKGROUND: Hematopoietic cell transplantation (HCT) is an effective treatment for pediatric patients with high-risk, refractory, or relapsed acute myeloid leukemia (AML). However, a large proportion of transplanted patients eventually die due to relapse. To improve overall survival, we propose a combined strategy based on cord blood (CB)-HCT with the application of AML-specific T cell receptor (TCR)-engineered T cell therapy derived from the same CB graft. METHODS: We produced CB-CD8+ T cells expressing a recombinant TCR (rTCR) against Wilms tumor 1 (WT1) while lacking endogenous TCR (eTCR) expression to avoid mispairing and competition. CRISPR-Cas9 multiplexing was used to target the constant region of the endogenous TCRα (TRAC) and TCRß (TRBC) chains. Next, an optimized method for lentiviral transduction was used to introduce recombinant WT1-TCR. The cytotoxic and migration capacity of the product was evaluated in coculture assays for both cell lines and primary pediatric AML blasts. RESULTS: The gene editing and transduction procedures achieved high efficiency, with up to 95% of cells lacking eTCR and over 70% of T cells expressing rWT1-TCR. WT1-TCR-engineered T cells lacking the expression of their eTCR (eTCR-/- WT1-TCR) showed increased cell surface expression of the rTCR and production of cytotoxic cytokines, such as granzyme A and B, perforin, interferon-γ (IFNγ), and tumor necrosis factor-α (TNFα), on antigen recognition when compared with WT1-TCR-engineered T cells still expressing their eTCR (eTCR+/+ WT1-TCR). CRISPR-Cas9 editing did not affect immunophenotypic characteristics or T cell activation and did not induce increased expression of inhibitory molecules. eTCR-/- WT1-TCR CD8+ CB-T cells showed effective migratory and killing capacity in cocultures with neoplastic cell lines and primary AML blasts, but did not show toxicity toward healthy cells. CONCLUSIONS: In summary, we show the feasibility of developing a potent CB-derived CD8+ T cell product targeting WT1, providing an option for post-transplant allogeneic immune cell therapy or as an off-the-shelf product, to prevent relapse and improve the clinical outcome of children with AML.

Pursuing dynamics of minimal residual leukemic subclones in relapsed and refractory acute myeloid leukemia during conventional therapy.

BACKGROUND: Acute myeloid leukemia (AML) is characterized by clonal heterogeneity, leading to frequent relapses and drug resistance despite intensive clinical therapy. Although AML's clonal architecture has been addressed in many studies, practical monitoring of dynamic changes in those subclones during relapse and treatment is still understudied. METHOD: Fifteen longitudinal bone marrow (BM) samples were collected from three relapsed and refractory (R/R) AML patients. Using droplet digital polymerase chain reaction (ddPCR), the frequencies of patient's leukemic variants were assessed in seven cell populations that were isolated from each BM sample based on cellular phenotypes. By quantifying mutant clones at the diagnosis, remission, and relapse stages, the distribution of AML subclones was sequentially monitored. RESULTS: Minimal residual (MR) leukemic subclones exhibit heterogeneous distribution among BM cell populations, including mature leukocyte populations. During AML progression, these subclones undergo active phenotypic transitions and repopulate into distinct cell population regardless of normal hematopoiesis hierarchic order. Of these, MR subclones in progenitor populations of patient BM predominantly carry MR leukemic properties, leading to more robust expansion and stubborn persistence than those in mature populations. Moreover, a minor subset of MR leukemic subclones could be sustained at an extremely low frequency without clonal expansion during relapse. CONCLUSIONS: In this study, we observed treatment persistent MR leukemic subclones and their phenotypic changes during the treatment process of R/R AML patients. This underscores the importance of preemptive inhibition of clonal promiscuity in R/R AML, proposing a practical method for monitoring AML MR subclones.

Exploring the role of GHRH antagonist MIA-602 in overcoming Doxorubicin-resistance in acute myeloid leukemia.

Acute myeloid leukemia (AML) is characterized by the rapid proliferation of mutagenic hematopoietic progenitors in the bone marrow. Conventional therapies include chemotherapy and bone marrow stem cell transplantation; however, they are often associated with poor prognosis. Notably, growth hormone-releasing hormone (GHRH) receptor antagonist MIA-602 has been shown to impede the growth of various human cancer cell lines, including AML. This investigation examined the impact of MIA-602 as monotherapy and in combination with Doxorubicin on three Doxorubicin-resistant AML cell lines, KG-1A, U-937, and K-562. The in vitro results revealed a significant reduction in cell viability for all treated wild-type cells. Doxorubicin-resistant clones were similarly susceptible to MIA-602 as the wild-type counterpart. Our in vivo experiment of xenografted nude mice with Doxorubicin-resistant K-562 revealed a reduction in tumor volume with MIA-602 treatment compared to control. Our study demonstrates that these three AML cell lines, and their Doxorubicin-resistant clones, are susceptible to GHRH antagonist MIA-602.

Interaction of olive oil-based propolis and caffeic acid phenethyl ester with methylprednisolone used in the treatment of human acute myeloid leukemia.

BACKGROUND: Methylprednisolone (MP) is a pharmaceutical agent employed in the management of Leukemia, which is a systemic malignancy that arises from abnormalities in the hematological system. Numerous investigations in the field of cancer research have directed their attention towards propolis, a natural substance with significant potential as a treatment-supportive agent. Its utilization aims to mitigate the potential adverse effects associated with chemotherapy medications. The objective of this study was to examine the impact of olive oil-based propolis (OEP) and caffeic acid phenethyl ester (CAPE) on the treatment of acute myeloid leukemia, as well as to determine if they exhibit a synergistic effect when combined with the therapeutic support product methylprednisolone. METHODS AND RESULTS: The proliferation of HL-60 cells was quantified using the WST-8 kit. The PI Staining technique was employed to do cell cycle analysis of DNA in cells subjected to OEP, CAPE, and MP, with subsequent measurement by flow cytometry. The apoptotic status of cells was determined by analyzing them using flow cytometry after staining with the Annexin V-APC kit. The quantification of apoptotic gene expression levels was conducted in HL-60 cells. In HL-60 cells, the IC50 dosages of CAPE and MP were determined to be 1 × 10- 6 M and 5 × 10- 4 M, respectively. The HL-60 cells were subjected to apoptosis and halted in the G0/G1 and G2/M phases of the cell cycle after being treated with MP, CAPE, and OEP. CONCLUSIONS: Propolis and its constituents have the potential to serve as effective adjunctive therapies in chemotherapy.

Innovations in conditioning and post-transplant maintenance in AML: genomically informed revelations on the graft-versus-leukemia effect.

Acute Myeloid Leukemia (AML) is the prototype of cancer genomics as it was the first published cancer genome. Large-scale next generation/massively parallel sequencing efforts have identified recurrent alterations that inform prognosis and have guided the development of targeted therapies. Despite changes in the frontline and relapsed standard of care stemming from the success of small molecules targeting FLT3, IDH1/2, and apoptotic pathways, allogeneic stem cell transplantation (alloHSCT) and the resulting graft-versus-leukemia (GVL) effect remains the only curative path for most patients. Advances in conditioning regimens, graft-vs-host disease prophylaxis, anti-infective agents, and supportive care have made this modality feasible, reducing transplant related mortality even among patients with advanced age or medical comorbidities. As such, relapse has emerged now as the most common cause of transplant failure. Relapse may occur after alloHSCT because residual disease clones persist after transplant, and develop immune escape from GVL, or such clones may proliferate rapidly early after alloHSCT, and outpace donor immune reconstitution, leading to relapse before any GVL effect could set in. To address this issue, genomically informed therapies are increasingly being incorporated into pre-transplant conditioning, or as post-transplant maintenance or pre-emptive therapy in the setting of mixed/falling donor chimerism or persistent detectable measurable residual disease (MRD). There is an urgent need to better understand how these emerging therapies modulate the two sides of the GVHD vs. GVL coin: 1) how molecularly or immunologically targeted therapies affect engraftment, GVHD potential, and function of the donor graft and 2) how these therapies affect the immunogenicity and sensitivity of leukemic clones to the GVL effect. By maximizing the synergistic action of molecularly targeted agents, immunomodulating agents, conventional chemotherapy, and the GVL effect, there is hope for improving outcomes for patients with this often-devastating disease.

Unlocking the potential: A novel prognostic index signature for acute myeloid leukemia.

Acute myeloid leukemia (AML) is an aggressive malignancy characterized by challenges in treatment, including drug resistance and frequent relapse. Recent research highlights the crucial roles of tumor microenvironment (TME) in assisting tumor cell immune escape and promoting tumor aggressiveness. This study delves into the interplay between AML and TME. Through the exploration of potential driver genes, we constructed an AML prognostic index (AMLPI). Cross-platform data and multi-dimensional internal and external validations confirmed that the AMLPI outperforms existing models in terms of areas under the receiver operating characteristic curves, concordance index values, and net benefits. High AMLPIs in AML patients were indicative of unfavorable prognostic outcomes. Immune analyses revealed that the high-AMLPI samples exhibit higher expression of HLA-family genes and immune checkpoint genes (including PD1 and CTLA4), along with lower T cell infiltration and higher macrophage infiltration. Genetic variation analyses revealed that the high-AMLPI samples associate with adverse variation events, including TP53 mutations, secondary NPM1 co-mutations, and copy number deletions. Biological interpretation indicated that ALDH2 and SPATS2L contribute significantly to AML patient survival, and their abnormal expression correlates with DNA methylation at cg12142865 and cg11912272. Drug response analyses revealed that different AMLPI samples tend to have different clinical selections, with low-AMLPI samples being more likely to benefit from immunotherapy. Finally, to facilitate broader access to our findings, a user-friendly and publicly accessible webserver was established and available at http://bioinfor.imu.edu.cn/amlpi. This server provides tools including TME-related AML driver genes mining, AMLPI construction, multi-dimensional validations, AML patients risk assessment, and figures drawing.

Targeting PRAME for acute myeloid leukemia therapy.

Despite significant progress in targeted therapy for acute myeloid leukemia (AML), clinical outcomes are disappointing for elderly patients, patients with less fit disease characteristics, and patients with adverse disease risk characteristics. Over the past 10 years, adaptive T-cell immunotherapy has been recognized as a strategy for treating various malignant tumors. However, it has faced significant challenges in AML, primarily because myeloid blasts do not contain unique surface antigens. The preferentially expressed antigen in melanoma (PRAME), a cancer-testis antigen, is abnormally expressed in AML and does not exist in normal hematopoietic cells. Accumulating evidence has demonstrated that PRAME is a useful target for treating AML. This paper reviews the structure and function of PRAME, its effects on normal cells and AML blasts, its implications in prognosis and follow-up, and its use in antigen-specific immunotherapy for AML.

Identification of cells of leukemic stem cell origin with non-canonical regenerative properties.

Despite most acute myeloid leukemia (AML) patients entering remission following chemotherapy, outcomes remain poor due to surviving leukemic cells that contribute to relapse. The nature of these enduring cells is poorly understood. Here, through temporal single-cell transcriptomic characterization of AML hierarchical regeneration in response to chemotherapy, we reveal a cell population: AML regeneration enriched cells (RECs). RECs are defined by CD74/CD68 expression, and although derived from leukemic stem cells (LSCs), are devoid of stem/progenitor capacity. Based on REC in situ proximity to CD34-expressing cells identified using spatial transcriptomics on AML patient bone marrow samples, RECs demonstrate the ability to augment or reduce leukemic regeneration in vivo based on transfusion or depletion, respectively. Furthermore, RECs are prognostic for patient survival as well as predictive of treatment failure in AML cohorts. Our study reveals RECs as a previously unknown functional catalyst of LSC-driven regeneration contributing to the non-canonical framework of AML regeneration.

Characterization of relapse-supportive monocytic cells in acute myeloid leukemia.

The precise identities of bone marrow resident cells contributing to AML relapse are not fully known. Hollands et al. report early evidence to support the existence of an aberrant monocytic cell population that appears to promote LSC expansion after cytarabine treatment.

From code to care: Clinician and researcher perspectives on an optimal therapeutic web portal for acute myeloid leukemia.

BACKGROUND: Acute myeloid leukemia (AML), a rapidly progressing cancer of the blood and bone marrow, is the most common and fatal type of adult leukemia. Therapeutic web portals have great potential to facilitate AML research advances and improve health outcomes by increasing the availability of data, the speed and reach of new knowledge, and the communication between researchers and clinicians in the field. However, there is a need for stakeholder research regarding their optimal features, utility, and implementation. METHODS: To better understand stakeholder perspectives regarding an ideal pan-Canadian web portal for AML research, semi-structured qualitative interviews were conducted with 17 clinicians, researchers, and clinician-researchers. Interview guides were inspired by De Laat's "fictive scripting", a method where experts are presented with scenarios about a future technology and asked questions about its implementation. Content analysis relied on an iterative process using themes extracted from both existing scientific literature and the data. RESULTS: Participants described potential benefits of an AML therapeutic portal including facilitating data-sharing, communication, and collaboration, and enhancing clinical trial matchmaking for patients, potentially based on their specific genomic profiles. There was enthusiasm about researcher, clinician, and clinician-researcher access, but some disagreement about the nature of potential patient access to the portal. Interviewees also discussed two key elements they believed to be vital to the uptake and thus success of a therapeutic AML web portal: credibility and user friendliness. Finally, sustainability, security and privacy concerns were also documented. CONCLUSIONS: This research adds to existing calls for digital platforms for researchers and clinicians to supplement extant modes of communication to streamline research and its dissemination, advance precision medicine, and ultimately improve patient prognosis and care. Findings are applicable to therapeutic web portals more generally, particularly in genomic and translational medicine, and will be of interest to portal end-users, developers, researchers, and policymakers.

Unveiling the signaling network of FLT3-ITD AML improves drug sensitivity prediction.

Currently, the identification of patient-specific therapies in cancer is mainly informed by personalized genomic analysis. In the setting of acute myeloid leukemia (AML), patient-drug treatment matching fails in a subset of patients harboring atypical internal tandem duplications (ITDs) in the tyrosine kinase domain of the FLT3 gene. To address this unmet medical need, here we develop a systems-based strategy that integrates multiparametric analysis of crucial signaling pathways, and patient-specific genomic and transcriptomic data with a prior knowledge signaling network using a Boolean-based formalism. By this approach, we derive personalized predictive models describing the signaling landscape of AML FLT3-ITD positive cell lines and patients. These models enable us to derive mechanistic insight into drug resistance mechanisms and suggest novel opportunities for combinatorial treatments. Interestingly, our analysis reveals that the JNK kinase pathway plays a crucial role in the tyrosine kinase inhibitor response of FLT3-ITD cells through cell cycle regulation. Finally, our work shows that patient-specific logic models have the potential to inform precision medicine approaches.

[Study of a patient with Myelodysplastic/myeloproliferative neoplasm with co-morbid neutrophilia and a novel NCOR1::GLYR1 fusion gene].

OBJECTIVE: To explore the genetic background for a patient with refractory myelodysplastic/myeloproliferative neoplasm (MDS/MPN) with co-morbid neutrophilia patient. METHODS: A MDS/MPN patient who was admitted to the First Affiliated Hospital of Nanjing Medical University in May 2021 was selected as the study subject. RNA sequencing was carried out to identify fusion genes in his peripheral blood mononuclear cells. Fusion gene sequence was searched through transcriptome-wide analysis with a STAR-fusion procedure. The novel fusion genes were verified by quantitative real-time PCR and Sanger sequencing. RESULTS: The patient, a 67-year-old male, had progressive thrombocytopenia. Based on the morphological and molecular examinations, he was diagnosed as MDS/MPN with co-morbid neutropenia, and was treated with demethylating agents and Bcl-2 inhibitors. Seventeen months after the diagnosis, he had progressed to AML. A novel fusion gene NCOR1::GLYR1 was identified by RNA-sequencing in his peripheral blood sample, which was verified by quantitative real-time PCR and Sanger sequencing. The patient had attained morphological remission after a DCAG regimen (a combinatory chemotherapy of decitabine, cytarabine, aclarubicin and granulocyte colony-stimulating factors) plus Chidamide treatment. A significant decrease in the NCOR1::GLYR1 expression was revealed by quantitative real-time PCR at post-chemotherapy evaluation. CONCLUSION: NCOR1::GLYR1 gene is considered as the pathogenic factor for the MDS/MPN patient with neutropenia.