Pathophysiology Of Acute Myeloid Leukemia Research Articles

STIM2 is involved in the regulation of apoptosis and the cell cycle in normal and malignant monocytic cells.

Calcium is a ubiquitous messenger that regulates a wide range of cellular functions, but its involvement in the pathophysiology of acute myeloid leukemia (AML) is not widely investigated. Here, we identified, from an analysis of The Cancer Genome Atlas and genotype-tissue expression databases, stromal interaction molecule 2 (STIM2) as being highly expressed in AML with monocytic differentiation and negatively correlated with overall survival. This was confirmed on a validation cohort of 407 AML patients. We then investigated the role of STIM2 in cell proliferation, differentiation, and survival in two leukemic cell lines with monocytic potential and in normal hematopoietic stem cells. STIM2 expression increased at the RNA and protein levels upon monocyte differentiation. Phenotypically, STIM2 knockdown drastically inhibited cell proliferation and induced genomic stress with DNA double-strand breaks, as shown by increased levels of phosphorylate histone H2AXγ (p-H2AXγ), followed by activation of the cellular tumor antigen p53 pathway, decreased expression of cell cycle regulators such as cyclin-dependent kinase 1 (CDK1)-cyclin B1 and M-phase inducer phosphatase 3 (CDC25c), and a decreased apoptosis threshold with a low antiapoptotic/proapoptotic protein ratio. Our study reports STIM2 as a new actor regulating genomic stability and p53 response in terms of cell cycle and apoptosis of human normal and malignant monocytic cells.

Presence of Recurrent Somatic Mutations in Mesenchymal Stromal Cell Fractions Isolated from Acute Myeloid Leukemia As an Evidence of Clonality

Introduction: Acute myeloid leukemia (AML) involves somatic mutations in hematopoietic stem cells (HSCs). Recent evidence suggests the bone marrow microenvironment, particularly mesenchymal stromal cells (MSCs), also influences AML development. Abnormalities in MSCs from AML patients have been observed (von der Heide et al., 2016), potentially impacting leukemia progression. This study aims to identify MSC somatic mutations and their consequences, further exploring their role in AML. Understanding MSCs' impact on the leukemic microenvironment may shed light on AML pathophysiology and guide targeted therapies, particularly benefiting patients with adverse risk disease. Methods: A total of 28 bone marrow cases were collected from AML patients with adverse risk, including those with complex karyotype, monosomy karyotype, chromosome 5/7/17 abnormalities, TP53 mutation, or relapsed/refractory AML. From these cases, 14 paired MSC and leukemic cell (LC) fractions were analyzed and are presented here. Magnetic bead sorting was used to isolate CD33+ LCs, while the plastic adherence method was employed for MSC culture. Following magnetic isolation, CD33- cells were plated in DMEM-LG with FBS and pen/strep, and MSC colonies formed within 48 hours. Contaminating cells were removed through media changes, and passaging was performed at 70-80% confluency. Flow cytometry at passage 3 characterized MSCs based on cell surface expression of CD105, CD73, and CD90, in accordance with the ISCT guideline. DNA and RNA were extracted from MSCs at passage 3 and subjected to whole exome sequencing (WES) using the Illumina platform, along with the LC fractions. WES aimed for 200X depth for the paired DNA samples. A standard bioinformatics pipeline was used for sequence alignment and variant calling, with variants requiring sufficient read depth (≥30x) and variant allele frequency in the case (>5%) and in the control (<5%). Synonymous variants were filtered out, and gene ontology and pathway enrichment analyses explored the biological significance and potential involvement in leukemogenesis of the identified mutations. Whole transcriptomics for gene expression analyses was also conducted for both MSC and LC fractions. Results: In 14 analyzed cases, a total of 548 somatic variants were identified in the MSC fraction, affecting 480 genes, including 518 nonsynonymous single nucleotide variants (SNVs), 7 stop-gain SNVs, 1 stoploss, 1 non-frameshift insertion, 2 frameshift deletions, 1 frameshift insertion, and 2 non-frameshift deletions, with 16 unknown variants. The average read depth was 75 (range: 15 - 887), and the average variant allele frequency was 50% (range: 11% - 90%). On average, 38 genes were mutated per MSC case, with 8 genes detected in at least 3 cases, 25 in exactly 2 cases, and 447 genes found in only one case. In the leukemic fraction, 686 somatic variants in 595 genes were identified, with an average read depth of approximately 75 (range: 10 - 2596) and an average variant allele frequency of 47% (range: 8% - 85%). On average, 48 mutations were detected per leukemic case, with 12 mutations found in at least 3 cases, 40 in 2 cases, and 543 in only one case. Among the 14 cases, 10 cases (71%) had mutations in known driver genes for AML ( FLT3, NPM1, IDH1, IDH2, DNMT3A, RUNX1, TP53) exclusively in the leukemic fraction. As seen in Figure 1., of the 480 genes mutated in the MSC fraction, 69 overlapped with the 595 genes mutated in the leukemic fraction, while 411 genes were uniquely mutated in the MSC fraction. Further analysis is ongoing, and pathway analysis will be conducted once the remaining 14 cases are processed. Conclusions: This study identifies distinct somatic mutations in AML patients' MSC and leukemic cell fractions, revealing genomic complexity and crosstalk impacting leukemia progression. Understanding the functional implications of these mutations is crucial for unraveling their roles in leukemogenesis and developing personalized therapeutic interventions targeting MSC somatic mutations.

Dysregulated Activating and Inhibitory Receptors on Natural Killer Cells Predicts Immune Escape and Poor Outcomes in Acute Myeloid Leukemia

Background: Although improvements have been made in understanding the pathophysiology of Acute Myeloid Leukemia (AML), heading to development of emerging therapies targeting leukemic stem cells, relapse is still a major problem leading to poor long-term survival and low cure rates. Of particular interest, Natural Killer (NK) cells are regulated by opposing signals from receptors that activate and inhibit effector function and are known to mediate anti-leukemic immunosurveillance in AML, but the mechanisms underlying the control of hematopoietic neoplasms by NK cells remains unclear and not yet explored as therapeutical options. Aims: We hypothesized that functionally impaired NK cells due to imbalanced expression of inhibitory and activating receptors can predict poor outcomes in AML. Methods: NK cell phenotypes based on the expression of DNAM-1 and NKG2D (activating) and NKG2A and KIR2DL1 (inhibitory) receptors on CD56+, CD56bright CD16- and CD56dim CD16+ NK subsets were profiled by multiparametric flow cytometry in 100 de novo AML bone marrow (BM) samples (Table 1), followed up from February 2016 to June 2022 and 17 healthy bone marrows (HBM). Correlations between NK phenotype with ELN2017 risk stratification, complete remission (CR), relapse (R), measurable residual disease (MRD), overall survival (OS) and relapse-free survival (RFS) were verified. Six BM from AML patients in remission after induction chemotherapy (AML-CR) were used to evaluate NK cell frequency and receptors recovery. Co-culture of AML-exposed CD56+ NK cells and K562 cell line was used to assay for killing (1:1, 5:1, 10:1 E:T ratios) and degranulation (CD107a). Mann Whitney, Kruskal-Wallis and mixed effects tests were performed to determine associations, and Log Rank test and Kaplan Meir curves were used for survival analysis. Results: The frequency of all NK cell subsets were decreased in AML (P < .01). AML CD56+ NK cells showed decreased expression of NKG2D (P < .01), a trending to decreased DNAM-1 and increased NKG2A (P = .04) and KIR2DL1 (P < .01), while recovering to near healthy values in AML-CR. Expression of both NKG2D and DNAM-1 activating receptors was decreased (P < .01), while inhibitory NKG2A (P = .02) and KIR2DL1 (P < .01) were considerably increased in CD56dim NK, which is known to carry out the most cytotoxic activity. The expression of both activating receptors by CD56dim subset was found to be decreased in ELN2017 adverse versus low/intermediate risk (NKG2D, P = .05; DNAM-1, P < .01), in relapse (P < .01), and with similar trends in MRD+ patients after remission induction. The opposite was observed for inhibitory receptors, found to be increased in adverse risk (P < .01), relapse (NKG2A, P < .01; KIRDL1, P < .05) and MRD+ (NKG2A, P = .03) patients. Degranulation (P < .01) and specific target cell death (5:1, P = .01; 10:1, P = .002) were significantly decreased in AML. Patients with lower frequency of CD56dim NK expressing low NKG2D and DNAM-1 showed less degranulation and specific target cell death (P = .03), whereas patients with higher inhibitory receptors demonstrated lower degranulation (NKG2A, P=0.06) and cytotoxicity (KIR2DL1, P=.005). Of note, RFS was decreased in patients with lower frequency of CD56+ NK cells (P = .02) and both OS and RFS were decreased in patients with lower frequency of CD56dim NK cells (OS, P = .04; RFS, P = .03) and in patients with lower expression of NKG2D (OS, P = .03; RFS, P = .008) and DNAM-1 (OS, P = .02; RFS, P = .11) activating receptors, strongly suggesting an imbalance between activation and inhibition of NK cell activity. Conclusion: Our data indicate that CD56dim NK show an exhaustion immunophenotype with high expression of KIR2DL1 and NKG2A inhibitory receptors and low expression of NKG2D and DNAM-1 activating receptors and that this imbalance leads to impaired cytotoxicity, compromised anti-leukemic activity and can be predictive of poor outcomes in AML, such as response to treatment, relapse and MRD positivity. Additionally, this NK phenotype at diagnosis could be considered an adverse risk prognostic factor associated with lower survival rates. Closing these gaps in the knowledge of NK-mediated immune evasion in leukemia is of significant interest for targeting the leukemic microenvironment by NK cell-mediated immunotherapy. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Genomic Alterations in Acute Myeloid Leukemia in Routine Clinical Practice

Acute Myeloid Leukemia (AML), the most common acute leukemia in adults, is a genetically heterogeneous disease. Genomic alterations condition the pathophysiology of AML. Nowadays, these changes are considered to be important biomarkers for risk stratification, treatment decisions (including new targeted drugs) and Minimal Residual Disease (MRD) monitoring during followup of AML. Positive MRD in AML patients is associated with a higher risk of relapse and shorter overall survival compared to MRD negative individuals. Nevertheless, MRD-targets, diagnostic techniques, time points of MRD determination, and analyzed material are not standardized. Thus, integration of MRD testing in individual AML patients in routine practice is still a workin- progress. This review article comprehensively focuses on key molecular biomarkers in AML and their utilization in clinical practice, especially regarding risk assessment and MRD testing. Moreover, new AML molecular-targeted therapies are briefly summarized here.

The proteogenomic subtypes of acute myeloid leukemia.

Acute myeloid leukemia (AML) is an aggressive blood cancer with a poor prognosis. We report a comprehensive proteogenomic analysis of bone marrow biopsies from 252 uniformly treated AML patients to elucidate the molecular pathophysiology of AML in order to inform future diagnostic and therapeutic approaches. In addition to in-depth quantitative proteomics, our analysis includes cytogenetic profiling and DNA/RNA sequencing. We identify five proteomic AML subtypes, each reflecting specific biological features spanning genomic boundaries. Two of these proteomic subtypes correlate with patient outcome, but none is exclusively associated with specific genomic aberrations. Remarkably, one subtype (Mito-AML), which is captured only in the proteome, is characterized by high expression of mitochondrial proteins and confers poor outcome, with reduced remission rate and shorter overall survival on treatment with intensive induction chemotherapy. Functional analyses reveal that Mito-AML is metabolically wired toward stronger complex I-dependent respiration and is more responsive to treatment with the BCL2 inhibitor venetoclax.

Lysosome-mediated chemoresistance in acute myeloid leukemia.

Despite the outstanding advances in understanding the biology underlying the pathophysiology of acute myeloid leukemia (AML) and the promising preclinical data published lastly, AML treatment still relies on a classic chemotherapy regimen largely unchanged for the past five decades. Recently, new drugs have been approved for AML, but the real clinical benefit is still under evaluation. Nevertheless, primary refractory and relapse AML continue to represent the main clinical challenge, as the majority of AML patients will succumb to the disease despite achieving a complete remission during the induction phase. As such, treatments for chemoresistant AML represent an unmet need in this disease. Although great efforts have been made to decipher the biological basis for leukemogenesis, the mechanism by which AML cells become resistant to chemotherapy is largely unknown. The identification of the signaling pathways involved in resistance may lead to new combinatory therapies or new therapeutic approaches suitable for this subset of patients. Several mechanisms of chemoresistance have been identified, including drug transporters, key secondary messengers, and metabolic regulators. However, no therapeutic approach targeting chemoresistance has succeeded in clinical trials, especially due to broad secondary effects in healthy cells. Recent research has highlighted the importance of lysosomes in this phenomenon. Lysosomes’ key role in resistance to chemotherapy includes the potential to sequester drugs, central metabolic signaling role, and gene expression regulation. These results provide further evidence to support the development of new therapeutic approaches that target lysosomes in AML.

Harnessing Macrophages through the Blockage of CD47: Implications for Acute Myeloid Leukemia.

Simple SummaryThe immune system is the first line of protection against infected and tumor cells. Macrophages are specialized immune cells that recognize these abnormal cells and eliminate them by a mechanism called phagocytosis. All normal cells express a protein called CD47 or “don’t eat me signal” to prevent their elimination through phagocytosis. Cancer cells, including leukemic cells, express higher levels of CD47 as a mechanism of protection against macrophage phagocytosis. CD47 blockade leads to an increase in phagocytosis of leukemic cells and better control of the disease. In this review, we explore CD47 function in normal conditions, its role in acute myeloid leukemia progression, and possible ways to block CD47 to enhance elimination of the leukemic cells improving the therapeutic options for patients with acute myeloid leukemia.CD47 is a surface membrane protein expressed by all normal tissues. It is the so-called “don’t eat me signal” because it protects the cells against phagocytosis. The CD47 interacts with the signal regulatory protein alpha (SIRPα) on the surface of macrophages, leading to downstream inhibitory signaling that dampens phagocytic capacity. Since macrophages exert immune surveillance against cancers, cancer cells overexpress CD47 to defend themselves against phagocytosis. Acute myeloid leukemia (AML) is a cancer of hematopoietic stem/progenitor cells (HSPC), and similar to other types of cancers, leukemic blasts show enhanced levels of CD47. In patients with AML, CD47 has been associated with a higher disease burden and poor overall survival. Blockage of CD47-SIRPα signaling leads to improved phagocytosis of AML cells and better overall survival in xenograft models. However, the introduction of a pro-phagocytic signal is needed to induce greater phagocytic capacity. These pro-phagocytic signals can be either Fc receptor stimulants (such as monoclonal antibodies) or natural pro-phagocytic molecules (such as calreticulin). Based on these pre-clinical findings, various clinical trials investigating the blockade of CD47-SIRPα interaction have been designed as monotherapy and in combination with other anti-leukemic agents. In this review, we will discuss CD47 biology, highlight its implications for AML pathophysiology, and explore the potential clinical translation of disrupting CD47-SIRPα to treat patients with AML.

Receptor Activator of NF-κB (RANK) Confers Resistance to Chemotherapy in AML and Associates with Dismal Disease Course.

Simple SummaryAcute myeloid leukemia (AML) is the most common form of acute leukemia in adults. Despite the emergence of new therapeutic agents in recent years, curation remains challenging, and new and better treatment options are needed. In the present study, we investigated the expression, prognostic significance, and functional role of the Receptor Activator of Nuclear Factor-κB (RANK) in AML. We found that RANK is expressed on leukemic cells in a substantial proportion of AML patients and is associated with a dismal disease course. We further demonstrated that signaling via RANK induces release of factors that favor AML cell survival and confers resistance to chemotherapeutics in AML treatment. Together, our findings identify RANK as novel prognostic marker and putative candidate for therapeutic intervention in AML to enhance response to treatment. Although treatment options of acute myeloid leukemia (AML) have improved over the recent years, prognosis remains poor. Better understanding of the molecular mechanisms influencing and predicting treatment efficacy may improve disease control and outcome. Here we studied the expression, prognostic relevance and functional role of the tumor necrosis factor receptor (TNFR) family member Receptor Activator of Nuclear Factor (NF)-κB (RANK) in AML. We conducted an experimental ex vivo study using leukemic cells of 54 AML patients. Substantial surface expression of RANK was detected on primary AML cells in 35% of the analyzed patients. We further found that RANK signaling induced the release of cytokines acting as growth and survival factors for the leukemic cells and mediated resistance of AML cells to treatment with doxorubicin and cytarabine, the most commonly used cytostatic compounds in AML treatment. In line, RANK expression correlated with a dismal disease course as revealed by reduced overall survival. Together, our results show that RANK plays a yet unrecognized role in AML pathophysiology and resistance to treatment, and identify RANK as “functional” prognostic marker in AML. Therapeutic modulation of RANK holds promise to improve treatment response in AML patients.

Tim-3 Mutation Might Play in the Pathophysiology of Acute Myeloid Leukemia

Genetic polymorphisms and expression of T-cell immunoglobulin mucin-3 (Tim-3) were associated with susceptibility and prognosis in some tumors, but the relationship between Tim-3 mutation and acute myeloid leukemia (AML) was rarely reported. This study explored the effects of Tim-3 mutations on AML. Four hundred and ninety-one de novo newly diagnosed AML patients were enrolled in this exploratory study. A genomic panel of 167 gene targets were detected by next-generation sequencing (NGS). A matched-pair analysis was designed for prognosis based on 1:2 ratio. 26 patients carried Tim-3 mutations, including 20 Tim-3 p.Y82C and other 6 mutations of p.E273K, p.E182N190del, p.Ter302E, p.A28V, p.R184W, p.G54fs. The median number of somatic mutations apart from Tim-3 was 6 and 7 in Tim-3 + and Tim-3 - groups (P=0.543), respectively. Tim-3 expression was lower, and white blood cell (WBC) at diagnose was higher (P=0.045) in Tim-3 + than Tim-3 - groups. The 2-year cumulative incidence of relapse was 50.8% and 28.7% (P=0.043), overall survival (OS) was 42.6% and 68.5% (P=0.048), and event-free survival (EFS) was 26.8% and 49.6% (P=0.028) in both groups, respectively. Multivariate analysis showed that WBC at diagnose was the risk factor (P=0.004, 0.011 and 0.000, respectively) while transplantation was the protective factor (P=0.015，0.000 and 0.000) for relapse, OS and EFS, and Tim-3 mutation was the risk factor for relapse (P=0.006) in the normal karyotype patients. In vitro, AML cell lines with Tim-3 p.Y82C overexpression revealed lower Tim-3 expression and apoptotic rate as well as lower sensitivity to cytarabine. The bioinformatic analysis also indicated Tim-3 low expression was associated with lower survival in AML patients (P=0.0009). Our findings provide new viewpoint that Tim-3 mutation results in Tim-3 lower expression and is a poor prognostic factor in AML. DisclosuresNo relevant conflicts of interest to declare.

Clinical Impact of Copy Number Variation Revealed By Next Generation Sequencing in Acute Myeloid Leukemia

Introduction: Conventional karyotype analysis is one of the most important diagnostic tools to determine the prognosis of acute myeloid leukemia (AML), in which more than 50% of cases are affected. However, the low sensitivity of this technique hampers the detection of small genetic alterations like Copy Number Variation (CNV) that could affect the pathophysiology and prognosis of the disease. Current modern genomic technologies based on next generation sequencing (NGS) are capable to detect CNV at low frequencies.Objective: To analyse CNV of genes related to myeloid neoplasms profile in AML patients at diagnosis and evaluate their connection with the mutational profile, and its possible influence on the clinical-biological phenotype and prognosis of the disease.Materials and methods: The CNV and mutational profile were analysed in samples from 380 AML patients, from PLATAFO-LMA reference centres (IMIBIC, Córdoba and Dr Negrín Las Palmas de Gran Canaria) by NGS, applying a panel of 30 genes (154 regions) related to myeloid neoplasms (Sophia Myeloid Solution®) on Ilumina Myseq platform.Results: NGS detected CNV in at least one gene in 103 AML patients (27.1%). NGS detected 103 gains and 206 losses of genetic material. The median number of genes affected by CNV was 2 (range 1-12). When comparing with conventional karyotype information, CNV provided additional information in 51% of the cases.The chromosomes 7, 11 and 21 were most affected with CNV, occurring in 79 (76.7%), 40 (38.8%) and 36 (35%) patients, respectively. The gains of genetic material occurred more frequently on chromosome 21 in U2AF1 and RUNX1 genes, in 13 patients each. The loss of genetic material in EZH2 and BRAF genes occurred mutually. Interestingly, we observed the tendency that patients with CNV (loss) in NPM1 gene had shorter overall survival compared to cases with NPM1 mutated and without CNV in this gene (1 month vs. 13 months, p = 0.072) (Figure 1). Moreover CNV (loss) in TP53 gene was associated with mutations in this gene, other than deletions (p <0.05).In addition, NGS detected 390 mutations distributed in 29 genes in 103 AML with CNV. The median number of mutations was 3 (range 1-10) (Figure 2). Furthermore, only 2 patients did not have any mutation in genes analysed. The distribution and frequency of genes affected by CNV and by mutations was different (Figure 3).Conclusions: The CNV of genes related to myeloid neoplasms are frequent in AML patients (27.1%) and provides additional information to the conventional karyotype in half of the cases. The loss of NPM1 gene could affect survival of AML patients. The use of NGS with CNV analysis provides important information on copy number alterations that are not detected by the karyotype, which could significantly affect the pathophysiology of AML and with potential clinical impact, especially in patients with normal karyotype. [Display omitted] DisclosuresHernández Rivas: Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene/BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees.

Diverse functions of long noncoding RNAs in acute myeloid leukemia: emerging roles in pathophysiology, prognosis, and treatment resistance.

Advancements in the next-generation sequencing technologies have identified rare transcripts of long noncoding RNAs (lncRNAs) in the genome of cancers, including in acute myeloid leukemia (AML). The purpose of this review is to highlight the contribution of lncRNAs in AML pathogenesis, prognosis, and chemoresistance. Several studies have recently reported that deregulated lncRNAs are novel key players in the development of AML and are associated with AML pathophysiology and may serve as prognostic indicators. A few aberrantly expressed lncRNAs that correlated with the recurrent genetic mutations in AML such as NPM1 and RUNX1 have recently been characterized. Moreover, a few lncRNAs in MLL-rearranged leukemia have been described. Additionally, the involvement of lncRNAs in AML chemoresistance has been postulated. Investigating the functional roles of the noncoding regions including lncRNAs, may provide novel insights into the pathophysiology, refine the prognostic schema, and provide novel therapeutic treatment strategies in AML.

DNAM-1/CD226 is functionally expressed on acute myeloid leukemia (AML) cells and is associated with favorable prognosis

DNAM-1 is reportedly expressed on cytotoxic T and NK cells and, upon interaction with its ligands CD112 and CD155, plays an important role in tumor immunosurveillance. It has also been reported to be functionally expressed by myeloid cells, but expression and function on malignant cells of the myeloid lineage have not been studied so far. Here we analyzed expression of DNAM-1 in leukemic cells of acute myeloid leukemia (AML) patients. We found substantial levels of DNAM-1 to be expressed on leukemic blasts in 48 of 62 (> 75%) patients. Interaction of DNAM-1 with its ligands CD112 and CD155 induced release of the immunomodulatory cytokines IL-6, IL-8 IL-10 and TNF-α by AML cells and DNAM-1 expression correlated with a more differentiated phenotype. Multivariate analysis did not show any association of DNAM-1 positivity with established risk factors, but expression was significantly associated with clinical disease course: patients with high DNAM-1 surface levels had significantly longer progression-free and overall survival compared to DNAM-1low patients, independently whether patients had undergone allogenic stem cell transplantation or not. Together, our findings unravel a functional role of DNAM-1 in AML pathophysiology and identify DNAM-1 as a potential novel prognostic maker in AML.

Interesting and Rare Case of Central Diabetes Insipidus in a Patient With Acute Myeloid Leukemia

Introduction: Central Diabetes Insipidus (CDI) is the lack of antidiuretic hormone (ADH) leading to impaired urinary concentration and manifests with extreme thirst and excessive urination. Patients unable to drink fluids are at risk of severe dehydration and hypernatremia. CDI can be a rare complication of acute myeloid leukemia (AML). The occurrence of AML with CDI is extremely rare with only few case reports published. This combination of AML with CDI has been reported to be associated with monosomy 7 and inversion (3) (q21q26) and portends an overall a very poor treatment response resulting in poor outcomes.Case Presentation: 66-year-old female with hypertension, polycythemia vera diagnosed in 2006 with transformation to AML in 2020. FISH studies revealed monosomy 7. Cytogenetic studies showed inv (3)(q21q26.2). Remission induction chemotherapy was initiated. Subsequently, neutropenic fever and sepsis secondary to Clostridium difficile colitis lead to hospitalization. Her sodium (Na) level gradually trended up and reached a peak of 157 mmol/l (range 136-145) and elevated serum osmolality at 311 mOsm/K with low urine osmolality 135 mOsm/K, low urine sodium at 13 and low urine specific gravity 1.006 concerning for CDI. She developed polyuria and received desmopressin (DDAVP) leading to improvements in urine osmolality to 267 mOsm/K, 30 minutes indicating CDI diagnosis. Her Na gradually normalized to 144 mmol/l, urine osmolality improved to 580 mOsm/K and urine specific gravity to 1.025. She is now on DDAVP 0.05 mg oral twice daily and her Na is in normal range. MRI pituitary did not show any evidence of metastatic lesion with intact pituitary bright spot. Her other pituitary hormonal workup was normal except for hypogonadotropic hypogonadism.Discussion: The pathophysiology of AML and CDI is unclear. Leukemic cells infiltration of the neurohypophysis; thrombosis of small vessels in hypothalamic nuclei and the posterior pituitary; alterations of the neutrophil migration placed on the chromosome 7 leading to glycoprotein gp 130 production, a cell surface marker on granulocytes are some of hypothesis suggested. CDI has a variable onset in the course of myeloid malignancies. MRI pituitary can be normal in most of the cases.

Acute myeloid leukemia: Treatment and research outlook for 2021 and the MD Anderson approach.

The unraveling of the pathophysiology of acute myeloid leukemia (AML) has resulted in rapid translation of the information into clinical practice. After more than 40 years of slow progress in AML research, the US Food and Drug Administration has approved nine agents for different AML treatment indications since 2017. In this review, we detail the progress that has been made in the research and treatment of AML, citing key publications related to AML research and therapy in the English literature since 2000. The notable subsets of AML include acute promyelocytic leukemia (APL), core-binding factor AML (CBF-AML), AML in younger patients fit for intensive chemotherapy, and AML in older/unfit patients (usually at the age cutoff of 60-70 years). We also consider within each subset whether the AML is primary or secondary (therapy-related, evolving from untreated or treated myelodysplastic syndrome or myeloproliferative neoplasm). In APL, therapy with all-trans retinoic acid and arsenic trioxide results in estimated 10-year survival rates of ≥80%. Treatment of CBF-AML with fludarabine, high-dose cytarabine, and gemtuzumab ozogamicin (GO) results in estimated 10-year survival rates of ≥75%. In younger/fit patients, the "3+7" regimen (3 days of daunorubicin + 7 days of cytarabine) produces less favorable results (estimated 5-year survival rates of 35%; worse in real-world experience); regimens that incorporate high-dose cytarabine, adenosine nucleoside analogs, and GO are producing better results. Adding venetoclax, FLT3, and IDH inhibitors into these regimens has resulted in encouraging preliminary data. In older/unfit patients, low-intensity therapy with hypomethylating agents (HMAs) and venetoclax is now the new standard of care. Better low-intensity regimens incorporating cladribine, low-dose cytarabine, and other targeted therapies (FLT3 and IDH inhibitors) are emerging. Maintenance therapy now has a definite role in the treatment of AML, and oral HMAs with potential treatment benefits are also available. In conclusion, AML therapy is evolving rapidly and treatment results are improving in all AML subsets as novel agents and strategies are incorporated into traditional AML chemotherapy. LAY SUMMARY: Ongoing research in acute myeloid leukemia (AML) is progressing rapidly. Since 2017, the US Food and Drug Administration has approved 10 drugs for different AML indications. This review updates the research and treatment pathways for AML.

TET2 mutations in acute myeloid leukemia: a comprehensive study in patients of Sindh, Pakistan.

BackgroundThe tet oncogene family member 2 (TET2) gene has been reported to be involved in DNA methylation and epigenetic regulation in acute myeloid leukemia (AML). Various studies have proven functional role of TET2 mutations in AML. We herein studied the frequency and genotype-phenotype correlation of TET2 gene in AML patients in Sindh, Pakistan.Patients and methodsThe current study was carried out at Liaquat University of Medical & Health Sciences, Jamshoro, Pakistan, in collaboration with National Institute of Blood Disease & Bone Marrow Transplant, Karachi, Pakistan, during the period from June 2019 to June 2020. A total of 130 patients diagnosed with AML were screened for TET2 mutations. Whole exome sequencing of 14 individuals was carried out to find the genetic variants in TET2 gene. The pathogenicity of the variants was predicted by SIFT, PolyPhen2, Mutation Taster and CADD Phred scores. The allele frequency of the variants was compared with global population using 1000 genomes project and Exome Aggregation Consortium (ExAC). Furthermore, exon 3 and exon 5 of the TET2 gene were sequenced by using Sanger sequencing. The findings were correlated with subtypes of AML and corresponding karyotypes.ResultsThrough the exome sequencing, 17 genetic variants (13 SNPs and four indels) were identified in 14 individuals. Of these, four variants that is, one frameshift deletion, one frameshift insertion and two nonsense variants were novel and not present in dbSNP151 database. Three novel variants were found in exon 3 including two frameshift variants that is, p.T395fs and G494fs, predicted as deleterious by CADD Phred scores, and one stop-gain variant (p.G898X) predicted as deleterious by Mutation Taster and CADD Phred scores. One novel non sense variant (p.Q1191X) was found in the exon 5 predicted as deleterious by SIFT, Mutation Taster and CADD Phred scores. Sanger sequencing analysis revealed one novel deletion at g105233851: del.TAGATAGA, and one novel SNP g;105233861 T>G identified in the TET2 gene. Majority of the exon 3 mutations were seen in the patients diagnosed with AML with maturation, and had a normal karyotype.ConclusionTET2 mutations were identified in around 16% of the total patients of our study indicating other mechanisms being involved in pathophysiology of AML in this cohort. The TET2 mutations provide a prognostic value in determining AML classification.

BCL2A1: A Novel Target in Refractory Acute Myeloid Leukemia with FLT3-ITD/D835 Dual Mutations

Internal tandem duplications in the juxtamembrane domain of FMS-like tyrosine kinase 3 gene (FLT3-ITD) and missense mutations in the gene's tyrosine-kinase domain (FLT3-TKD) play critical roles in the pathophysiology of acute myeloid leukemia (AML). Recent study revealed that AML cells resistant to quizartinib, a type II TKI, consist of heterogeneous clonal populations harboring wild-type FLT3 as well as FLT3-ITD, FLT3-TKD and FLT3-ITD/TKD mutations, and on- and off-target mechanisms may contribute to the resistance to TKIs. To overcome the heterogeneous resistance mechanisms of FLT3-ITD and TKD mutations, various combinatorial therapies have been investigated. For example, BCL-2 inhibition in the presence of TKIs increased survival a murine FLT3-ITD AML model, and a phase Ib/II clinical trial of a combination of quizartinib with venetoclax, a BCL2 inhibitor is ongoing in relapsed/refractory FLT3-mutant AML patients (NCT03735875). To dissect underlying mechanisms of drug-resistance and exploring new targets in refractory AML with FLT3-ITD and TKD mutations, we investigated alterations of transcriptome signatures by analyzing AML samples with FLT3-ITD/D835 dual mutations. Previously, we reported BCL2A1 transcriptomes were upregulated in primary AML cells with FLT3-ITD/D835 dual mutations compared to cells with FLT3-ITD mutations only. This was recapitulated in the MV4-11 cells harboring FLT3-ITD/D835 dual mutations after 6 month-exposure to quizartinib. The MV4-11 cells with the FLT3-ITD/D835 dual mutations became resistant to quizartinib, and the cells also became resistant to venetoclax, a BCL2 inhibitor (Yamatani et al. ASH 2019). In this study, we further investigated BCL2A1 as new target in refractory AML with FLT3-ITD/D835 dual mutations. First, we examined whether overexpression of BCL2A1 induces drug-resistance in MV4-11 and Molm13 cell lines with FLT3-ITD. While parental MV4-11 and Molm13 cells are sensitive to venetoclax and quizartinib, MV4-11 and Molm13 cells transfected with lentivirus carrying BCL2A1 became resistant to venetoclax (IC50: MV4-11 with BCL2A1 over-expression &amp;gt;1000 nM vs. mock vector 0.71 nM; Molm13 with over-expression &amp;gt;1000 nM vs. mock vector 0.38 nM, 72h). In contrast, the sensitivity to quizartinib was retained in the BCL2A1 overexpressing MV4-11 and Molm13 cells. These findings indicate that the overexpression of BCL2A1 could play a role in the acquired resistance to venetoclax, but not to quizartinib. Bromodomain-containing protein 4 (BRD4), a family member of bromodomain and extra-terminal motif (BET) is known to transcriptionally modulate BCL2A1 gene expression. Next, we examined effects of CPI-0610, a BET inhibitor, on MV4-11 cells with FLT3-ITD or the FLT3-ITD/D835 dual mutation. CPI-0610 inhibited cell growth of MV4-11 cells by inducing apoptosis irrespective of co-existing FLT3 mutations (IC50: FLT3-ITD/D835, 255 nM vs. FLT3-ITD, 191 nM, 72h). Immunoblotting analyses confirmed that BET inhibition by CPT-0610 decreased the expression of BCL2A1 in MV4-11 cells FLT3-ITD/D835. WIn conclusion, transcriptome analysis and molecular pharmacological approaches identified alterations in the anti-apoptotic BCL2 family proteins in double-mutant FLT3 leukemias. BCL2A1 upregulation might be involved in drug resistance of FLT3-ITD/D835 dual mutant AML cells, and could be a promising new target in refractory AML with FLT3-ITD/D835 dual mutations. Disclosures Konopleva: Cellectis: Research Funding; Eli Lilly: Research Funding; Calithera: Research Funding; Sanofi: Research Funding; Ascentage: Research Funding; AstraZeneca: Research Funding; Agios: Research Funding; Stemline Therapeutics: Consultancy, Research Funding; Kisoji: Consultancy; Genentech: Consultancy, Research Funding; F. Hoffmann La-Roche: Consultancy, Research Funding; Forty-Seven: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding; Reata Pharmaceutical Inc.;: Patents &amp; Royalties: patents and royalties with patent US 7,795,305 B2 on CDDO-compounds and combination therapies, licensed to Reata Pharmaceutical; Rafael Pharmaceutical: Research Funding; Ablynx: Research Funding; Amgen: Consultancy. Carter:Syndax: Research Funding; AstraZeneca: Research Funding; Amgen: Research Funding; Ascentage: Research Funding. Andreeff:Daiichi-Sankyo; Breast Cancer Research Foundation; CPRIT; NIH/NCI; Amgen; AstraZeneca: Research Funding; Centre for Drug Research &amp; Development; Cancer UK; NCI-CTEP; German Research Council; Leukemia Lymphoma Foundation (LLS); NCI-RDCRN (Rare Disease Clin Network); CLL Founcdation; BioLineRx; SentiBio; Aptose Biosciences, Inc: Membership on an entity's Board of Directors or advisory committees; Amgen: Research Funding; Daiichi-Sankyo; Jazz Pharmaceuticals; Celgene; Amgen; AstraZeneca; 6 Dimensions Capital: Consultancy.

Assessment of the Diagnostic Potential of miR-29a-3p and miR-92a-3p as Circulatory Biomarkers in Acute Myeloid Leukemia.

Background:Acute myeloid leukemia (AML) is a set of Myeloproliferative neoplasms that are identified by excessive growth of myeloid blasts and production of abnormal blood cells. AML is the most common type of acute leukemia that occurs in adults. In addition, AML progresses rapidly and is considered a fatal disease. Thus, there is an urgent need to find new targets for molecularly designed therapies. In This study, we evaluated the circulatory levels of microRNA-29a-3p (miR-29a-3p) and miR-92a-3p beside exploring the expression pattern of their target gene myeloid cell leukemia sequence1 (MCL1) to investigate the role of these molecules in AML pathophysiology and to assess their ability to diagnose AML patients. Methods:40 adult AML patients along with 20 healthy subjects were enrolled in this study. Plasma were separated from venous blood samples, collected on EDTA, of all individuals were used to assess circulating miRNAs’ levels. In the meantime, total RNA was extracted from isolated leukocytes and was used to quantify target mRNA transcript levels. Results:Our data revealed that the circulating levels of miR-29a-3p and miR-92a-3p exhibited significant reduction in 90% and 100% of AML patients, respectively, when compared to the control group (p<0.001). On the other hand, the transcript level of the target gene of these miRNAs, MCL1, showed a sharp increase in 77.5% (p<0.001) of AML patients, along with a negative correlation with its regulatory miRNAs, miR-29a-3p and miR-92a-3p. Conclusion:Our data validates the negative regulatory role of miR-29a-3p and miR-92a-3p to the expression levels of MCL1 in peripheral blood and indicates that these miRNAs can be used as non-invasive diagnostic markers. Furthermore, our study highlights the therapeutic potential of miR-29a-3p and miR-92a-3p to target and downregulate a very important gene (MCL1), which is highly implicated in the pathogenesis of AML.

Optimizing Use of Newly Approved Agents for Acute Myeloid Leukemia.

Until recently, treatment advances in acute myeloid leukemia (AML) had been slow since the 1970s. However, in the past few years, as the understanding of the pathophysiology of AML has advanced, numerous treatments have been approved by the U.S. Food & Drug Administration. This article reviews the mechanisms of action, indications, and clinical trial details for eight novel agents, as well as the current discussions surrounding monitoring minimal residual disease.

A Critical Review of Animal Models Used in Acute Myeloid Leukemia Pathophysiology.

Acute myeloid leukemia (AML) is one of the most frequent, complex, and heterogeneous hematological malignancies. AML prognosis largely depends on acquired cytogenetic, epigenetic, and molecular abnormalities. Despite the improvement in understanding the biology of AML, survival rates remain quite low. Animal models offer a valuable tool to recapitulate different AML subtypes, and to assess the potential role of novel and known mutations in disease progression. This review provides a comprehensive and critical overview of select available AML animal models. These include the non-mammalian Zebrafish and Drosophila models as well as the mammalian rodent systems, comprising rats and mice. The suitability of each animal model, its contribution to the advancement of knowledge in AML pathophysiology and treatment, as well as its advantages and limitations are discussed. Despite some limitations, animal models represent a powerful approach to assess toxicity, and permit the design of new therapeutic strategies.

The Regulatory Roles of Long Noncoding RNAs in Acute Myeloid Leukemia.

In this post-genomic era, long noncoding RNAs (lncRNAs) are rapidly gaining recognition for their crucial roles across diverse biological processes and contexts. The human blood system is no exception, where dozens of lncRNAs have been established as regulators of normal and/or malignant hematopoiesis, and where ongoing works continue to uncover novel lncRNA functions. Our review focuses on lncRNAs that are involved in the pathogenesis of acute myeloid leukemia (AML) and the mechanisms through which they control gene expression in this disease context. We also comment on genome-wide sequencing or profiling studies that have implicated large sets of lncRNAs in AML pathophysiology.