Clinical networking results in continuous improvement of the outcome of patients with acute promyelocytic leukemia.

The introduction of all-trans retinoic acid (ATRA) combined with anthracyclines has significantly improved the outcomes for patients with acute promyelocytic leukemia (APL), and this strategy remains the standard of care in countries where arsenic trioxide is not affordable. However, data from national registries and real-world databases indicate that low- and middle-income countries (LMIC) still face disappointing results, mainly due to high induction mortality and suboptimal management of complications. The American Society of Hematology established the International Consortium on Acute Leukemias (ICAL) to address this challenge through international clinical networking. Here, we present the findings from the ICAPL study involving 806 patients with APL recruited in Brazil, Chile, Paraguay, Peru, and Uruguay. The induction mortality rate has decreased to 14.6% compared to the pre-ICAL rate of 32%. Multivariable logistic regression analysis revealed as factors associated with induction death: age ≥ 40 years, ECOG = 3, high-risk status based on the PETHEMA/GIMEMA classification, albumin level ≤ 3.5 g/dL, bcr3 PML/RARA isoform, the interval between presenting symptoms to diagnosis exceeding 48 hours, and the occurrence of central nervous system and pulmonary bleeding. With a median follow-up of 53 months, the estimated 4-year overall survival (OS) rate is 81%, the 4-year disease-free survival (DFS) rate is 80%, and the 4-year cumulative incidence of relapse (CIR) rate is 15%. These results parallel those observed in studies conducted in high-income countries, highlighting the long-term effectiveness of developing clinical networks to improve clinical care and infrastructure in LMIC.

Ratio of stemness to interferon signalling as a biomarker and therapeutic target of myeloproliferative neoplasm progression to acute myeloid leukaemia.

Progression to aggressive secondary acute myeloid leukaemia (sAML) poses a significant challenge in the management of myeloproliferative neoplasms (MPNs). Since the physiopathology of MPN is closely linked to the activation of interferon (IFN) signalling and that AML initiation and aggressiveness is driven by leukaemia stem cells (LSCs), we investigated these pathways in MPN to sAML progression. We found that high IFN signalling correlated with low LSC signalling in MPN and AML samples, while MPN progression and AML transformation were characterized by decreased IFN signalling and increased LSC signature. A high LSC to IFN expression ratio in MPN patients was associated with adverse clinical prognosis and higher colony forming potential. Moreover, treatment with hypomethylating agents (HMAs) activates the IFN signalling pathway in MPN cells by inducing a viral mimicry response. This response is characterized by double-stranded RNA (dsRNA) formation and MDA5/RIG-I activation. The HMA-induced IFN response leads to a reduction in LSC signature, resulting in decreased stemness. These findings reveal the frequent evasion of viral mimicry during MPN-to-sAML progression, establish the LSC-to-IFN expression ratio as a progression biomarker, and suggests that HMAs treatment can lead to haematological response in murine models by re-activating dsRNA-associated IFN signalling.

Phenformin increases early hematopoietic progenitors in the Jak2V617F murine model.

BACKGROUND: Myeloproliferative neoplasms (MPN) are disorders characterized by an alteration at the hematopoietic stem cell (HSC) level, where the JAK2 mutation is the most common genetic alteration found in classic MPN (polycythemia vera, essential thrombocythemia, and primary myelofibrosis). We and others previously demonstrated that metformin reduced splenomegaly and platelets counts in peripheral blood in JAK2V617F pre-clinical MPN models, which highlighted the antineoplastic potential of biguanides for MPN treatment. Phenformin is a biguanide that has been used to treat diabetes, but was withdrawn due to its potential to cause lactic acidosis in patients. AIMS: We herein aimed to investigate the effects of phenformin in MPN disease burden and stem cell function in Jak2V617F-knockin MPN mice. RESULTS: In vitro phenformin treatment reduced cell viability and increased apoptosis in SET2 JAK2V67F cells. Long-term treatment with 40 mg/kg phenformin in Jak2V617F knockin mice increased the frequency of LSK, myeloid progenitors (MP), and multipotent progenitors (MPP) in the bone marrow. Phenformin treatment did not affect peripheral blood counts, spleen weight, megakaryocyte count, erythroid precursors frequency, or ex vivo clonogenic capacity. Ex vivo treatment of bone marrow cells from Jak2V617F knockin mice with phenformin did not affect hematologic parameters or engraftment in recipient mice. CONCLUSIONS: Phenformin increased the percentages of LSK, MP, and MPP populations, but did not reduce disease burden in Jak2V617F-knockin mice. Additional studies are necessary to further understand the effects of phenformin on early hematopoietic progenitors.

STMN1 is highly expressed and contributes to clonogenicity in acute promyelocytic leukemia cells.

Stathmin 1 (STMN1) is a microtubule-destabilizing protein highly expressed in hematological malignancies and involved in proliferation and differentiation. Although a previous study found that the PML-RARα fusion protein, which contributes to the pathophysiology of acute promyelocytic leukemia (APL), positively regulates STMN1 at the transcription and protein activity levels, little is known about the role of STMN1 in APL. In this study, we aimed to investigate the STMN1 expression levels and their associations with laboratory, clinical, and genomic data in APL patients. We also assessed the dynamics of STMN1 expression during myeloid cell differentiation and cell cycle progression, and the cellular effects of STMN1 silencing and pharmacological effects of microtubule-stabilizing drugs on APL cells. We found that STMN1 transcripts were significantly increased in samples from APL patients compared with those of healthy donors (all p < 0.05). However, this had no effect on clinical outcomes. STMN1 expression was associated with proliferation- and metabolism-related gene signatures in APL. Our data confirmed that STMN1 was highly expressed in early hematopoietic progenitors and reduced during cell differentiation, including the ATRA-induced granulocytic differentiation model. STMN1 phosphorylation was predominant in a pool of mitosis-enriched APL cells. In NB4 and NB4-R2 cells, STMN1 knockdown decreased autonomous cell growth (all p < 0.05) but did not impact ATRA-induced apoptosis and differentiation. Finally, treatment with paclitaxel (as a single agent or combined with ATRA) induced microtubule stabilization, resulting in mitotic catastrophe with repercussions for cell viability, even in ATRA-resistant APL cells. This study provides new insights into the STMN1 functions and microtubule dynamics in APL.

NT157, an IGF1R-IRS1/2 inhibitor, exhibits antineoplastic effects in pre-clinical models of chronic myeloid leukemia.

Chronic myeloid leukemia (CML) is successfully treated with BCR-ABL1 tyrosine kinase inhibitors, but a significant percentage of patients develop resistance. Insulin receptor substrate 1 (IRS1) has been shown to constitutively associate with BCR-ABL1, and IRS1-specific silencing leads to antineoplastic effects in CML cell lines. Here, we characterized the efficacy of NT157, a pharmacological inhibitor of IGF1R-IRS1/2, in CML cells and observed significantly reduced cell viability and proliferation, accompanied by induction of apoptosis. In human K562 cells and in murine Ba/F3 cells, engineered to express either wild-type BCR-ABL1 or the imatinib-resistant BCR-ABL1T315I mutant, NT157 inhibited BCR-ABL1, IGF1R, IRS1/2, PI3K/AKT/mTOR, and STAT3/5 signaling, increased CDKN1A, FOS and JUN tumor suppressor gene expression, and reduced MYC and BCL2 oncogenes. NT157 significantly reduced colony formation of human primary CML cells with minimal effect on normal hematopoietic cells. Exposure of primary CML cells harboring BCR-ABL1T315I to NT157 resulted in increased apoptosis, reduced cell proliferation and decreased phospho-CRKL levels. In conclusion, NT157 has antineoplastic effects on BCR-ABL1 leukemogenesis, independent of T315I mutational status.

DNMT1-interacting RNAs block gene-specific DNA methylation.

DNA methylation was first described almost a century ago; however, the rules governing its establishment and maintenance remain elusive. Here we present data demonstrating that active transcription regulates levels of genomic methylation. We identify a novel RNA arising from the CEBPA gene locus that is critical in regulating the local DNA methylation profile. This RNA binds to DNMT1 and prevents CEBPA gene locus methylation. Deep sequencing of transcripts associated with DNMT1 combined with genome-scale methylation and expression profiling extend the generality of this finding to numerous gene loci. Collectively, these results delineate the nature of DNMT1-RNA interactions and suggest strategies for gene-selective demethylation of therapeutic targets in human diseases.

Kinetics of BCR::ABL1 transcript levels and molecular relapse after tyrosine kinase inhibitors discontinuation in chronic myeloid leukemia patients: preliminary results from the DES-CML study.

Tyrosine kinase inhibitors (TKI) have revolutionized the treatment of patients with chronic myeloid leukemia. Patients who achieve sustained deep molecular response are eligible for treatment discontinuation. DES-CML is an ongoing, phase 2 multicentric discontinuation trial. Adult patients with CML in chronic phase with typical BCR::ABL1 transcripts, stable deep molecular response (MR4.5 IS) for two years, and no previous resistance were eligible. Patients underwent a phase of TKI dose de-escalation for six months before discontinuation. TKI was reintroduced at the previous dose if the patient lost major molecular response (MMR) at any time. This study aimed to assess the impact of BCR-ABL transcript kinetics during TKI de-escalation and discontinuation phases on treatment-free survival. So far, the study recruited 41 patients, and 38 patients discontinued therapy (4 were in the second discontinuation attempt). Eleven patients lost MMR, one during the de-escalation phase and ten after discontinuation. 24-month treatment-free survival was 66% (95% CI: 48-84%) in a median follow-up of 7 (1-30) months. No patient lost hematological response or had disease progression. A higher rate of molecular relapses occurred in patients with fluctuating BCR::ABL1 levels after the discontinuation phase (with loss of MR4.5, but no loss of MMR) (P=0.04, HR-4.86 (1.03-22.9) but not confirmed in the multivariate analysis. The longer duration of TKI treatment (P=0.03, HR-1.02, 95%CI - 1.00-1.04) and MMR (P=0.004, HR-0.95, 95%CI - 0.92-098) were independent factors of a lower relapse rate.

Diagnosis and management of acute promyelocytic leukemia: Brazilian consensus guidelines 2024 on behalf of the Brazilian Association of Hematology, Hemotherapy and Cellular Therapy.

Improvements in clinical assessment have occurred since the last published recommendations on the diagnosis and treatment of acute promyelocytic leukemia in 2013. Here, a committee of specialists of the Brazilian Association of Hematology, Hemotherapy and Cellular Therapy presents a comprehensive review on the current knowledge, focusing on the advances in diagnosis, risk assessment, and frontline and salvage therapy. The concept of urgent diagnosis is explored as well as the management of critical situations such as coagulopathy and differentiation syndrome. Recent adjustments in risk stratification based on white blood cell counts only are presented together with the incorporation of chemo-free regimens for non-high-risk patients. Special conditions such as acute promyelocytic leukemia in children, the elderly and pregnant women are discussed. Finally, acute promyelocytic leukemia is presented as a highly curable disease because of the real possibility of targeted therapy towards differentiation, and, paradoxically, as a serious and urgent condition that deserves prompt recognition and management to avoid early mortality.

Microcosting analysis of haematopoietic stem cell transplantation and chemotherapy with intermediate doses of cytarabine in the treatment of acute myeloid leukaemia.

BACKGROUND: Acute myeloid leukaemia (AML) is considered a costly disease. Depending on the risk stratification, the patient may receive consolidation with cycles of intermediate doses of cytarabine, auto-HSCT or allo-HSCT according to availability in each service and the availability of a compatible donor. Literature data indicate that safety and effectiveness do not differ between consolidation therapy with intermediate-dose cytarabine or auto-HSCT, and so the cost can help physicians and health managers in their choice. METHOD: The cost of the second consolidation was compared in 18 to 60-year-old patients with de novo AML who were included in the International Consortium of Acute Myeloid Leukaemia (ICAML) protocol. Patients treated with auto-HSCT or intermediate doses of cytarabine (IDAC) were analysed during four years using the microcosting methodology. RESULTS: The mean costs for auto-HSCT and IDAC were BRL$ 34,900.95 (range: 23,611.36-41,229.59) and 15,231.64 (range: 6,546.36-23,253.53), respectively. The mean duration of in-hospital stay was 88.4 (93-133) and 94 (50-153) days, respectively. The mean cost of the four cycles of treatment was BRL$ 114.212,78 for auto-HSCT and BRL$ 121.980,93 for the chemotherapy group. Regardless of the type of treatment, the input that had the greatest economic impact was hospital admission, mainly due to infections. CONCLUSION: Auto-HSCT had a lower average cost per patient and hospitalization rate than chemotherapy.

Differential cytotoxic activity of pharmacological inhibitors of IGF1R-related pathways in JAK2V617F driven cells.

Myeloproliferative neoplasms (MPN) belong to a group of clonal diseases of hematopoietic stem cells characterized by aberrant proliferation of mature myeloid lineages. The constitutive activation of the JAK2/STAT signaling pathway is now well established to play a central role in MPN pathogenesis; however, accumulating evidence now indicates that the IGF1R-mediated signaling pathway contributes to the maintenance of the malignant phenotype. Studies using inhibitors of IGF1-mediated signaling have reported cytotoxic effects in cellular and murine models of MPN, but no consensus has been reached regarding the potency and efficacy of inhibitors of the IGF1R-related pathway in this context. In the present study, we compared the potency and efficacy of three inhibitors of IGF1R-related pathways in a JAK2V617F-driven cellular model. These inhibitors (NT157, OSI-906, and NVP-AEW54) present antineoplastic activity with similar efficacy in Ba/F3 JAK2V617F cells, with NT157 showing the greatest potency. Both the induction of apoptosis and reduction in cell proliferation were associated with the observed reduction in cell viability. Downregulation of JAK2/STAT signaling was an advantageous off-target effect of all three inhibitors. These preclinical studies reinforce the potential of the IGF1R-related pathway as a therapeutic target in MPN.

Hippo pathway-related genes expression is deregulated in myeloproliferative neoplasms.

Myeloproliferative neoplasms (MPN) are hematological disorders characterized by increased proliferation of precursor and mature myeloid cells. MPN patients may present driver mutations in JAK2, MPL, and CALR genes, which are essential to describe the molecular mechanisms of MPN pathogenesis. Despite all the new knowledge on MPN pathogenesis, many questions remain to be answered to develop effective therapies to cure MPN or impair its progression to acute myeloid leukemia. The present study examined the expression levels of the Hippo signaling pathway members in patients with polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF), as well as the role that they play in disease pathogenesis. The Hippo pathway is a tumor suppressor pathway that participates in the regulation of cell proliferation, differentiation, and death. Our main finding was that the expression of tumor suppressor genes from Hippo pathway were downregulated and seemed to be associated with cell resistance to apoptosis and increased proliferation rate. Therefore, the decreased expression of Hippo pathway-related genes may contribute to the malignant phenotype, apoptosis resistance, and cell proliferation in MPN pathogenesis.

Bioactive Lipids as Chronic Myeloid Leukemia's Potential Biomarkers for Disease Progression and Response to Tyrosine Kinase Inhibitors.

Chronic myelogenous leukemia (CML) is a myeloproliferative neoplasm that expresses the Philadelphia chromosome and constitutively activated Bcr-Abl tyrosine kinase in hematopoietic progenitor cells. Bcr-Abl tyrosine-kinase inhibitors (TKI) do not definitively cure all CML patients. The efficacy of TKI is reduced in CML patients in the blastic phase-the most severe phase of the disease-and resistance to this drug has emerged. There is limited knowledge on the underlying mechanisms of disease progression and resistance to TKI beyond BCR-ABL1, as well as on the impact of TKI treatment and disease progression on the metabolome of CML patients. The present study reports the metabolomic profiles of CML patients at different phases of the disease treated with TKI. The plasma metabolites from CML patients were analyzed using liquid chromatography, mass spectrometry, and bioinformatics. Distinct metabolic patterns were identified for CML patients at different phases of the disease and for those who were resistant to TKI. The lipid metabolism in CML patients at advanced phases and TKI-resistant patients is reprogrammed, as detected by analysis of metabolomic data. CML patients who were responsive and resistant to TKI therapy exhibited distinct enriched pathways. In addition, ceramide levels were higher and sphingomyelin levels were lower in resistant patients compared with control and CML groups. Taken together, the results here reported established metabolic profiles of CML patients who progressed to advanced phases of the disease and failed to respond to TKI therapy as well as patients in remission. In the future, an expanded study on CML metabolomics may provide new potential prognostic markers for disease progression and response to therapy.

Philadelphia-negative myeloproliferative neoplasms display alterations in monocyte subpopulations frequency and immunophenotype.

Philadelphia-negative myeloproliferative neoplasms (MPN) are clonal hematological diseases associated with driver mutations in JAK2, CALR, and MPL genes. Moreover, several evidence suggests that chronic inflammation and alterations in stromal and immune cells may contribute to MPN's pathophysiology. We evaluated the frequency and the immunophenotype of peripheral blood monocyte subpopulations in patients with polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (MF). Peripheral blood monocytes from PV (n = 16), ET (n = 16), and MF (n = 15) patients and healthy donors (n = 10) were isolated and submitted to immunophenotyping to determine the frequency of monocyte subpopulations and surface markers expression density. Plasma samples were used to measure the levels of soluble CD163, a biomarker of monocyte activity. PV, ET, and MF patients presented increased frequency of intermediate and non-classical monocytes and reduced frequency of classical monocytes compared to controls. Positivity for JAK2 mutation was significantly associated with the percentage of intermediate monocytes. PV, ET, and MF patients presented high-activated monocytes, evidenced by higher HLA-DR expression and increased soluble CD163 levels. The three MPN categories presented increased frequency of CD56+ aberrant monocytes, and PV and ET patients presented reduced frequency of CD80/86+ monocytes. Therefore, alterations in monocyte subpopulations frequency and surface markers expression pattern may contribute to oncoinflammation and may be associated with the pathophysiology of MPN.

Bone Marrow Soluble Mediator Signatures of Patients With Philadelphia Chromosome-Negative Myeloproliferative Neoplasms.

BACKGROUND: Essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (PMF) are clonal hematological diseases classified as Philadelphia chromosome-negative myeloproliferative neoplasms (MPN). MPN pathogenesis is associated with the presence of somatic driver mutations, bone marrow (BM) niche alterations, and tumor inflammatory status. The relevance of soluble mediators in the pathogenesis of MPN led us to analyze the levels of cytokines, chemokines, and growth factors related to inflammation, angiogenesis and hematopoiesis regulation in the BM niche of MPN patients. METHODS: Soluble mediator levels in BM plasma samples from 17 healthy subjects, 28 ET, 19 PV, and 16 PMF patients were determined using a multiplex assay. Soluble mediator signatures were created from categorical analyses of high mediator producers. Soluble mediator connections and the correlation between plasma levels and clinic-laboratory parameters were also analyzed. RESULTS: The soluble mediator signatures of the BM niche of PV patients revealed a highly inflammatory and pro-angiogenic milieu, with increased levels of chemokines (CCL2, CCL5, CXCL8, CXCL12, CXCL10), and growth factors (GM-CSF M-CSF, HGF, IFN-γ, IL-1ß, IL-6Ra, IL-12, IL-17, IL-18, TNF-α, VEGF, and VEGF-R2). ET and PMF patients presented intermediate inflammatory and pro-angiogenic profiles. Deregulation of soluble mediators was associated with some clinic-laboratory parameters of MPN patients, including vascular events, treatment status, risk stratification of disease, hemoglobin concentration, hematocrit, and red blood cell count. CONCLUSIONS: Each MPN subtype exhibits a distinct soluble mediator signature. Deregulated production of BM soluble mediators may contribute to MPN pathogenesis and BM niche modification, provides pro-tumor stimuli, and is a potential target for future therapies.

Clinical and molecular profile of a Brazilian cohort of patients with classical BCR-ABL1-negative myeloproliferative neoplasms.

BACKGROUND: The classical BCR-ABL1-negative myeloproliferative neoplasms (MPNs) are Polycythemia Vera (PV), Essential Thrombocythemia (ET) and Primary Myelofibrosis (PMF). In developing countries, there are few reports that truly reveal the clinical setting of these patients. Therefore, we aimed to characterize a single center MPN population with a special focus on the correct diagnosis based on the recent review of the WHO criteria for the diagnosis of myeloid neoplasms. METHODS: This retrospective study analyzed data from medical records of patients with classical BCR-ABL1-negative MPNs diagnosed from January 1997 to October 2017 and followed at the University Hospital of Ribeirão Preto Medical School. RESULTS: A total of 162 patients were assessed, 61 with PV, 50 with ET, and 51 with PMF. The mutational status analysis revealed that 113 (69.3%) harbored the JAK2V617F mutation, 23 (14.1%), the CALR mutation, and 12 (7.4%) had a triple-negative status. None of the patients were found to have mutations on the thrombopoietin receptor gene (MPL), including some ET and PMF patients who were not tested. Among the PV patients, 57 (93.5%) were positive for the JAK2V617F mutation, one (1.6%) presented an in-frame deletion JAK2 exon 12 mutation and one (1.6%) presented a missense JAK2 exon 9 mutation, not previously described. The overall survival was lower in the triple-negative patients with PMF, when compared to the JAK2V617F or CALR-mutated (p = 0.002). CONCLUSION: The frequency of somatic mutations and survival in our cohort, stratified according to the respective disease, was consistent with the literature data, despite some limitations. Further prospective epidemiological studies of MPN cohorts are encouraged in developing countries.

Differential cytokine network profile in polycythemia vera and secondary polycythemia.

Polycythemia vera (PV) is a clonal disorder resulting from neoplastic transformation of hematopoietic stem cells, while secondary polycythemia (SP) is a disease characterized by increased absolute red blood cell mass caused by stimulation of red blood cell production. Although the physiopathology of SP and PV is distinct, patients with these diseases share similar symptoms. The early differential diagnosis may improve the quality of life and decrease the disease burden in PV patients, as well as enable curative treatment for SP patients. PV is considered an oncoinflammatory disease because PV patients exhibit augmented levels of several pro-inflammatory cytokines. In this sense, we examined whether analysis of the cytokine production profile of SP and PV patients would help to distinguish them, despite their clinical similarities. Here we reported that SP patients exhibited decreased plasma levels of, IL-17A, IFN-γ, IL-12p70 and TNF-α when compared with PV patients, suggesting that analysis of the cytokine production profile may be an useful diagnostic biomarker to distinguish PV from SP patients.

[From the molecular model to the impact on prognosis: an overview on acute promyelocytic leukemia]. / Do paradigma molecular ao impacto no prognóstico: uma visão da leucemia promielocítica aguda.

Acute promyelocytic leukemia (APL) is a model of clinical applicability of the knowledge of molecular physiopathology. It is characterized by recurrent genetic involvement of the retinoic acid alpha receptor. The consequence is a protein with low sensibility to its ligand and a myeloid maturation arrest. However, higher doses of all-trans-retinoic acid (ATRA) are able to supersede this deficiency and this is the mainstay of APL treatment leading to over 80% disease free survival, when adequately treated. Epidemiologically, it differs from other acute myeloid leukemia due to a higher incidence in young adults and in countries of "Latin" colonization. Differing from excellent results observed in developed countries, APL mortality in Brazil is still high, despite the wide availability of drugs.

Philadelphia-negative myeloproliferative neoplasms as disorders marked by cytokine modulation.

BACKGROUND: Cytokines are key immune mediators in physiological and disease processes, whose increased levels have been associated with the physiopathology of hematopoietic malignancies, such as myeloproliferative neoplasms. METHODS: This study examined the plasma cytokine profiles of patients with essential thrombocythemia, primary myelofibrosis, polycythemia vera and of healthy subjects, and analyzed correlations with JAK2 V617F status and clinical-hematological parameters. RESULTS: The proinflammatory cytokine levels were increased in myeloproliferative neoplasm patients, and the presence of the JAK2 V617F mutation was associated with high IP-10 levels in primary myelofibrosis patients. CONCLUSIONS: Essential thrombocythemia, primary myelofibrosis, and polycythemia vera patients exhibited different patterns of cytokine production, as revealed by cytokine network correlations. Together, these findings suggest that augmented cytokine levels are associated with the physiopathology of myeloproliferative neoplasms.