FLT3 internal tandem duplication associates with adverse outcome and gene- and microRNA-expression signatures in patients 60 years of age or older with primary cytogenetically normal acute myeloid leukemia: a Cancer and Leukemia Group B study. Blood. 2010;116:3622-3626. [PMID: 20656931 DOI: 10.1182/blood-2010-05-283648]

The function and regulation of CCAAT/enhancer binding protein ε

In recent years, studies on the structure, function, and regulation of the C/EBPε gene have become an essential topic in the field of many diseases. CCAAT/enhancer-binding protein ε (C/EBPε) is the fifth member of the transcription factor CCAAT/C/EBP family of transcription factors. It plays crucial roles in cell proliferation, differentiation, immunity, energy metabolism, and hematopoiesis. C/EBPε plays essential roles in regulating the hematopoietic system, including myeloid cell development and maturation, participation in the body’s immune responses, and prevention of infections. C/EBPε function is regulated by phosphorylation, acetylation, methylation, and other types of genes. This review related to C/EBPε structure, function and regulation provides a theoretical basis for subsequent research in this area. C/EBPε is an emerging therapeutic target and thus provides new strategies for disease prevention and control.

Off-the-shelf CAR-engineered natural killer cells targeting FLT3 enhance killing of acute myeloid leukemia

The majority of patients with acute myeloid leukemia (AML) succumb to the disease or its complications, especially among older patients. Natural killer (NK) cells have been shown to have antileukemic activity in patients with AML; however, to our knowledge, primary NK cells armed with a chimeric antigen receptor (CAR) targeting antigens associated with AML as an "off-the-shelf" product for disease control have not been explored. We developed frozen, off-the-shelf allogeneic human NK cells engineered with a CAR recognizing FLT3 and secreting soluble interleukin-15 (IL-15) (FLT3 CAR_sIL-15 NK) to improve in vivo NK cell persistence and T-cell activation. FLT3 CAR_sIL-15 NK cells had higher cytotoxicity and interferon gamma secretion against FLT3+ AML cell lines when compared with activated NK cells lacking an FLT3 CAR or soluble IL-15. Frozen and thawed allogeneic FLT3 CAR_sIL-15 NK cells prolonged survival of both the MOLM-13 AML model as well as an orthotopic patient-derived xenograft AML model when compared with control NK cells. FLT3 CAR_sIL-15 NK cells showed no cytotoxicity against healthy blood mononuclear cells or hematopoietic stem cells. Collectively, our data suggest that FLT3 is an AML-associated antigen that can be targeted by frozen, allogeneic, off-the-shelf FLT3 CAR_sIL-15 NK cells that may provide a novel approach for the treatment of AML.

Treatment of older adults with FLT3-mutated AML: Emerging paradigms and the role of frontline FLT3 inhibitors

FLT3 is the most frequently mutated gene in acute myeloid leukemia (AML), with FLT3 internal tandem duplication (ITD) mutations being associated with a more aggressive clinical course. While two large, randomized clinical trials have shown a survival benefit with the frontline use of an oral FLT3 inhibitor (midostaurin or quizartinib) in patients with FLT3-mutated AML, the role of FLT3 inhibitors in older adults with newly diagnosed FLT3-mutated AML remains unclear. A definitive improvement in survival has not been observed in intensively treated patients over 60 years of age receiving frontline FLT3 inhibitors. Furthermore, many patients with FLT3-mutated AML are unsuitable for intensive chemotherapy due to age and/or comorbidities, and this population represents a particular unmet need. For these older patients who are unfit for intensive approaches, azacitidine + venetoclax is a new standard of care and is used by many clinicians irrespective of FLT3 mutation status. However, FLT3-ITD mutations confer resistance to venetoclax and are a well-established mechanism of relapse to lower-intensity venetoclax-based regimens, leading to short durations of remission and poor survival. Preclinical and clinical data suggest synergy between FLT3 inhibitors and venetoclax, providing rationale for their combination. Novel strategies to safely incorporate FLT3 inhibitors into the standard hypomethylating agent + venetoclax backbone are now being explored in this older, less fit population with newly diagnosed FLT3-mutated AML, with encouraging early results. Herein, we discuss the frontline use of FLT3 inhibitors in older adults with FLT3-mutated AML, including the potential role of FLT3 inhibitors in combination with intensive chemotherapy and as part of novel, lower-intensity doublet and triplet regimens in this older population.

Modern Risk Stratification of Acute Myeloid Leukemia in 2023: Integrating Established and Emerging Prognostic Factors

An accurate estimation of AML prognosis is complex since it depends on patient-related factors, AML manifestations at diagnosis, and disease genetics. Furthermore, the depth of response, evaluated using the level of MRD, has been established as a strong prognostic factor in several AML subgroups. In recent years, this rapidly evolving field has made the prognostic evaluation of AML more challenging. Traditional prognostic factors, established in cohorts of patients treated with standard intensive chemotherapy, are becoming less accurate as new effective therapies are emerging. The widespread availability of next-generation sequencing platforms has improved our knowledge of AML biology and, consequently, the recent ELN 2022 recommendations significantly expanded the role of new gene mutations. However, the impact of rare co-mutational patterns remains to be fully disclosed, and large international consortia such as the HARMONY project will hopefully be instrumental to this aim. Moreover, accumulating evidence suggests that clonal architecture plays a significant prognostic role. The integration of clinical, cytogenetic, and molecular factors is essential, but hierarchical methods are reaching their limit. Thus, innovative approaches are being extensively explored, including those based on "knowledge banks". Indeed, more robust prognostic estimations can be obtained by matching each patient's genomic and clinical data with the ones derived from very large cohorts, but further improvements are needed.

Checkpoint Inhibitors in Acute Myeloid Leukemia

The prognosis of acute myeloid leukemia (AML) remains unsatisfactory. Among the reasons for the poor response to therapy and high incidence of relapse, there is tumor cell immune escape, as AML blasts can negatively influence various components of the immune system, mostly weakening T-cells. Since leukemic cells can dysregulate immune checkpoints (ICs), receptor-based signal transductors that lead to the negative regulation of T-cells and, eventually, to immune surveillance escape, the inhibition of ICs is a promising therapeutic strategy and has led to the development of so-called immune checkpoint inhibitors (ICIs). ICIs, in combination with conventional chemotherapy, hypomethylating agents or targeted therapies, are being increasingly tested in cases of AML, but the results reported are often conflicting. Here, we review the main issues concerning the immune system in AML, the main pathways leading to immune escape and the results obtained from clinical trials of ICIs, alone or in combination, in newly diagnosed or relapsed/refractory AML.

LncRNA MAFG-AS1-induced acute myeloid leukemia development via modulating miR-147b/HOXA9

Recent references discovered that lncRNAs acted roles in malignant cancer development. However, the role of MAFG-AS1 in acute myeloid leukemia (AML) development remains unknown. MAFG-AS1 and miR-147b were determined in AML cells and specimens using qRT-PCR assay. Cell proliferation was detected by CCK-8 analysis and flow cytometry was carried out to measure cell cycle. Luciferase reporter analysis was done to determine the mechanism of MAFG-AS1 and miR-147b. We noted that MAFG-AS1 was overexpressed in AML cells and in serum and bone narrow from AML compared with normal controls specimen. Elevated expression of MAFG-AS1 increased cell growth, cycle and EMT in AML cell HL-60 cell. MAFG-AS1 sponged miR-147b expression in HL-60 cell. Moreover, miR-147b was downregulated in AML cells and in serum and bone narrow from AML compared with normal control specimen. miR-147b was negatively correlated with MAFG-AS1 in the serum and bone narrow of AML cases. We illustrated that HOXA9 was one target of miR-147b and ectopic expression of MAFG-AS1 enhanced HOXA9 expression HL-60 cell. Forced expression of MAFG-AS1 induced cell growth, cycle, and EMT via promoting HOXA9. These data illustrated that MAFG-AS1 acted as one oncogenic gene and accelerated AML progression via modulating miR-147b/HOXA9 axis.

Loss of MiR-155 Sensitizes FLT3-ITD+AML to Chemotherapy and FLT3 Inhibitors via Glycolysis Blocking by Targeting PIK3R1

FLT3 tyrosine kinase inhibitors in combination with chemotherapy have shown some success in patients with FLT3 mutations. But a variety of mechanisms have led to the rapid resistance to the treatment. One of the most prominent is the metabolic alteration on aerobic glycolysis. We aim to explore the role of a high expressing microRNA, miR-155, in mediating resistance to chemotherapy and FLT3 inhibitor treatment. The deep sequencing data mining revealed the connection between glycolysis and drug resistance. MV411 cells with miR-155 knockout (KO) not only had increased sensitivity to FLT3 inhibitors but also Adriamycin (ADM) treatment. When combined with glycolysis inhibition the treatment response in MV411 cells further increased. Whereas in miR-155 KO cells, a lower glucose consumption level and lactic acid level were observed, and western blotting showed a decreased expression of key enzymes in glycolysis pathways. A negative correlation between PIK3R1 and miR-155 level can be observed in the sequencing data from FLT3-ITD⁺ AML patients. Moreover, luciferase reporter assay revealed that the 3'UTR of PIK3R1 mRNA can interact with the seed sequence of miR-155-5p. In conclusion, the loss of miR-155 increased treatment sensitivity to both chemotherapy and FLT3 inhibitors in FLT3-ITD⁺ AML cells via glycolysis blocking by targeting PIK3R1.

Malignant clonal evolution drives multiple myeloma cellular ecological diversity and microenvironment reprogramming

Background

Multiple myeloma (MM) is a heterogeneous disease with different patterns of clonal evolution and a complex tumor microenvironment, representing a challenge for clinicians and pathologists to understand and dissect the contribution and impact of polyclonality on tumor progression.

Methods

In this study, we established a global cell ecological landscape of the bone marrow (BM) from MM patients, combining single-cell RNA sequencing and single-molecule long-read genome sequencing data.

Results

The malignant mutation event was localized to the tumor cell clusters with shared mutation of ANK1 and IFITM2 in all malignant subpopulations of all MM patients. Therefore, these two variants occur in the early stage of malignant clonal origin to mediate the malignant transformation of proplasmacytes or plasmacytes to MM cells. Tumor cell stemness index score and pseudo-sequential clonal evolution analysis can be used to divide the evolution model of MM into two clonal origins: types I and IX. Notably, clonal evolution and the tumor microenvironment showed an interactive relationship, in which the evolution process is not only selected by but also reacts to the microenvironment; thus, vesicle secretion enriches immune cells with malignant-labeled mRNA for depletion. Interestingly, microenvironmental modification exhibited significant heterogeneity among patients.

Conclusions

This characterization of the malignant clonal evolution pattern of MM at the single-cell level provides a theoretical basis and scientific evidence for a personalized precision therapy strategy and further development of a potential new adjuvant strategy combining epigenetic agent and immune checkpoint blockade.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12943-022-01648-z.

Triclosan targets miR-144 abnormal expression to induce neurodevelopmental toxicity mediated by activating PKC/MAPK signaling pathway

Although the previous research confirmed that triclosan (TCS) induced an estrogen effect by acting on a novel G-protein coupled estrogen-membrane receptor (GPER), the underlying mechanisms by which downstream pathways induce neurotoxicity remain unclear after TCS activation of GPER. By employing a series of techniques (Illumina miRNA-seq, RT-qPCR, and artificial intervention of miRNA expression), we screened out four important miRNAs, whose target genes were directly/indirectly involved in neurodevelopment and neurobehavior. Especially, the miR-144 up-regulation caused vascular malformation and severely affected hair-cell development and lateral-line-neuromast formation, thereby causing abnormal motor behavior. After microinjecting 1-2-cell embryos, the similar phenotypic malformations as those induced by TCS were observed, including aberrant neuromast, cuticular-plate development and motor behavior. By KEGG pathway enrichment analysis, these target genes were demonstrated to be mainly related to the PKC/MAPK signaling pathway. When a PKC inhibitor was used to suppress the PKC/MAPK pathway, a substantial alleviation of TCS-induced neurotoxicity was observed. Therefore, TCS acts on GPER to activate the downstream PKC/MAPK signaling pathway, further up-regulating miR-144 expression and causing abnormal modulation of these nerve-related genes to trigger neurodevelopmental toxicity. These findings unravel the molecular mechanisms of TCS-induced neurodegenerative diseases, and offer theoretical guidance for TCS-pollution early warning and management.

Validation of AML-score in Older Adults Receiving CPX-351 Intensive Induction Chemotherapy for Treatment of Secondary Acute Myeloid Leukemia

INTRODUCTION/BACKGROUND

The AML-Score has been validated in patients receiving traditional induction chemotherapies but not CPX-351. We conducted a retrospective analysis to evaluate, among patients with secondary acute myeloid leukemia who received intensive induction with CPX-351, if the AML-Score associates with (1) complete remission (CR) and (2) early mortality (EM) within 60 days of induction.

MATERIALS AND METHODS

We abstracted demographic and clinical data from consecutive patients receiving CPX-351 at Sidney Kimmel Cancer Center at Thomas Jefferson University Hospital between September 2017 and November 2020. We used descriptive statistics and receiver operating curves to evaluate the relationship between AML-Score and rates of CR and EM.

RESULTS

In total, 40 patients were included. 27 (67.5%) were male, 27 (67.5%) were white, 36 (90.0%) were not Hispanic or Latino, and 29 (72.5%) were aged ≥60 years. Twenty-seven patients (67.5%) had a CR, and 4 (10%) experienced EM. Observed rates of CR and EM generally increased with increasing predicted risk. The area under the curve was 0.75 (95% CI 0.60-0.90) for CR and 0.82 (95% CI 0.68-0.96) for EM.

CONCLUSION

The AML-Score tool trends in the correct direction for predicting CR and EM, and thus may facilitate oncologist prognostication and treatment planning for patients receiving CPX-351. However, its clinical utility is limited by its underestimation of the risk of CR and overestimation of the risk of EM. Further validation in a larger cohort is needed to calculate accurate point estimates of CR and EM risk in this population.

Acute Myeloid Leukemia-Related Proteins Modified by Ubiquitin and Ubiquitin-like Proteins

Acute myeloid leukemia (AML), the most common form of an acute leukemia, is a malignant disorder of stem cell precursors of the myeloid lineage. Ubiquitination is one of the post-translational modifications (PTMs), and the ubiquitin-like proteins (Ubls; SUMO, NEDD8, and ISG15) play a critical role in various cellular processes, including autophagy, cell-cycle control, DNA repair, signal transduction, and transcription. Also, the importance of Ubls in AML is increasing, with the growing research defining the effect of Ubls in AML. Numerous studies have actively reported that AML-related mutated proteins are linked to Ub and Ubls. The current review discusses the roles of proteins associated with protein ubiquitination, modifications by Ubls in AML, and substrates that can be applied for therapeutic targets in AML.

OUP accepted manuscript

As in younger patients, allogeneic stem cell transplantation (alloHSCT) offers the best chance for durable remission in older patients (≥60 years) with acute myeloid leukemia (AML). However, defining the best treatment strategy (and in particular, whether or not to proceed to alloHSCT) for elderly patients with AML remains a difficult decision for the hematologist, since potential toxicity of conditioning regimens, risks of graft-versus-host disease, impaired immune reconstitution and the need for prolonged immunosuppression may be of major concern in these vulnerable patients with complex needs. Hopefully, significant progress has been made over the past decade in alloHSCT for elderly patients and current evidence suggests that chronological age per se (between 60 and 75) is not a reliable predictor of outcome after alloHSCT. Here, we review the current state of alloHSCT in elderly patients with AML and also discuss the different approaches currently being investigated to improve both accessibility to as well as success of alloHSCT in these patients.

Risk factors affect accurate prognosis in ASXL1-mutated acute myeloid leukemia

Background

The epigenetic regulator additional sex combs-like 1 (ASXL1) is an adverse prognostic factor in acute myeloid leukemia (AML). However, the mutational spectrum and prognostic factors of ASXL1-mutated (ASXL1+) AML are largely unknown. We aim to evaluate the risk factors influencing the prognosis of ASXL1+ AML.

Methods

We performed next-generation sequencing (NGS) in 1047 cases of de novo AML and discovered 91 ASXL1+ AML (8.7%). The Log-Rank test and Kaplan-Meier were used to evaluate survival rate, and the Cox regression model was used to analyze multivariate analysis.

Results

In a total of 91 ASXL1+ AML, 86% had one or more co-mutations. The factors that had adverse impact on overall survival (OS) and event-free survival (EFS) are defined as high risk factors, including age ≥ 60 years, WBC count ≥ 50 × 10⁹/L, FLT3-ITD mutations, RUNX1 mutations, and absence of AML1-ETO fusion gene. ASXL1 mutations without any risk factor were classified as single-hit ASXL1+ AML; ASXL1 mutations accompanied with one of the risk factors was referred to as double-hit ASXL1+ AML; ASXL1 mutations with two or more of the risk factors were designated as triple-hit ASXL1+ AML. The combination of these risk factors had a negative influence on the prognosis of ASXL1+ AML. The median OS was not attained in single-hit ASXL1+ AML, 29.53 months in double-hit ASXL1+ AML, and 6.67 months in triple-hit ASXL1+ AML (P = 0.003). The median EFS was not attained in single-hit ASXL1+ AML, 29.53 months in double-hit ASXL1+ AML, and 5.47 months in triple-hit ASXL1+ AML (P = 0.002). Allogenic hematopoietic stem cell transplantation (allo-HSCT) improved the prognosis of double/triple-hit ASXL1+ AML patients.

Conclusions

Our study provided new insights into the mutational spectrum and prognostic factors of ASXL1+ AML patients. Our primary data suggest that the risk factors in ASXL1+ AML contribute to the poor outcome of these patients. The management of ASXL1+ AML patients should be based on the risk factors and allo-HSCT is highly recommended for consolidation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02233-y.

Clinical Applications of MicroRNAs in Acute Myeloid Leukemia: A Mini-Review

MicroRNAs (miRs) are short non-coding RNAs, typically 18-25 nucleotides in length, that are critically important, through their direct effects on target mRNAs, in a variety of cellular processes including cell differentiation, proliferation and survival. Dysregulated miR expression has been identified in numerous cancer types including acute myeloid leukemia (AML). From a clinical standpoint, several miRs have been shown to associate with prognosis in AML patients. Furthermore, they also carry the potential to be used as biomarkers and to inform medical decision making. In addition, several preclinical studies have provided strong rationale to develop novel therapeutic strategies to target miRs in AML. This review will focus on potential clinical applications of miRs in adult AML and will discuss unique miR signatures in specific AML subtypes, their role in prognostication and response to therapy, as well as miRs that are promising therapeutic targets and ongoing clinical trials directed towards targeting clinically relevant miRs in AML that could allow for improvements in current treatment strategies.

Genetic identification of patients with AML older than 60 years achieving long-term survival with intensive chemotherapy

To design a simple and reproducible classifier predicting the overall survival (OS) of patients with acute myeloid leukemia (AML) ≥60 years of age treated with 7 + 3, we sequenced 37 genes in 471 patients from the ALFA1200 (Acute Leukemia French Association) study (median age, 68 years). Mutation patterns and OS differed between the 84 patients with poor-risk cytogenetics and the 387 patients with good (n = 13), intermediate (n = 339), or unmeasured (n = 35) cytogenetic risk. TP53 (hazards ratio [HR], 2.49; P = .0003) and KRAS (HR, 3.60; P = .001) mutations independently worsened the OS of patients with poor-risk cytogenetics. In those without poor-risk cytogenetics, NPM1 (HR, 0.57; P = .0004), FLT3 internal tandem duplications with low (HR, 1.85; P = .0005) or high (HR, 3.51; P < 10-4) allelic ratio, DNMT3A (HR, 1.86; P < 10-4), NRAS (HR, 1.54; P = .019), and ASXL1 (HR, 1.89; P = .0003) mutations independently predicted OS. Combining cytogenetic risk and mutations in these 7 genes, 39.1% of patients could be assigned to a "go-go" tier with a 2-year OS of 66.1%, 7.6% to the "no-go" group (2-year OS 2.8%), and 3.3% of to the "slow-go" group (2-year OS of 39.1%; P < 10-5). Across 3 independent validation cohorts, 31.2% to 37.7% and 11.2% to 13.5% of patients were assigned to the go-go and the no-go tiers, respectively, with significant differences in OS between tiers in all 3 trial cohorts (HDF [Hauts-de-France], n = 141, P = .003; and SAL [Study Alliance Leukemia], n = 46; AMLSG [AML Study Group], n = 223, both P < 10-5). The ALFA decision tool is a simple, robust, and discriminant prognostic model for AML patients ≥60 years of age treated with intensive chemotherapy. This model can instruct the design of trials comparing the 7 + 3 standard of care with less intensive regimens.

MicroRNA as a Prognostic and Diagnostic Marker in T-Cell Acute Lymphoblastic Leukemia

T cell acute lymphoblastic leukemia (T-ALL) is a biologically and genetically heterogeneous disease with a poor prognosis overall and several subtypes. The neoplastic transformation takes place through the accumulation of numerous genetic and epigenetic abnormalities. There are only a few prognostic factors in comparison to B cell precursor acute lymphoblastic leukemia, which is characterized by a lower variability and more homogeneous course. The microarray and next-generation sequencing (NGS) technologies exploring the coding and non-coding part of the genome allow us to reveal the complexity of the genomic and transcriptomic background of T-ALL. miRNAs are a class of non-coding RNAs that are involved in the regulation of cellular functions: cell proliferations, apoptosis, migrations, and many other processes. No miRNA has become a significant prognostic and diagnostic factor in T-ALL to date; therefore, this topic of investigation is extremely important, and T-ALL is the subject of intensive research among scientists. The altered expression of many genes in T-ALL might also be caused by wide miRNA dysregulation. The following review focuses on summarizing and characterizing the microRNAs of pediatric patients with T-ALL diagnosis and their potential future use as predictive factors.

The prognostic impact of FLT3-ITD and NPM1 mutation in adult AML is age-dependent in the population-based setting

In acute myeloid leukemia (AML) FLT3 internal tandem duplication (ITD) and nucleophosmin 1 (NPM1) mutations provide prognostic information with clinical relevance through choice of treatment, but the effect of age and sex on these molecular markers has not been evaluated. The Swedish AML Registry contains data on FLT3-ITD and NPM1 mutations dating to 2007, and 1570 adult patients younger than 75 years, excluding acute promyelocytic leukemia, had molecular results reported. Females more often had FLT3ITD and/or NPM1mut (FLT3ITD: female, 29%; male, 22% [P = .0015]; NPM1mut: female, 36%; male, 27% [P = .0001]), and more males were double negative (female, 53%; male, 64%; P < .0001). Patients with FLT3ITD were younger than those without (59 vs 62 years; P = .023), in contrast to patients with NPM1mut (62 vs 60 years; P = .059). Interestingly, their prognostic effect had a strong dependence on age: FLT3ITD indicated poor survival in younger patients (<60 years; P = .00003), but had no effect in older patients (60-74 years; P = .5), whereas NPM1mut indicated better survival in older patients (P = .00002), but not in younger patients (P = .95). In FLT3ITD/NPM1mut patients, the survival was less dependent on age than in the other molecular subsets. These findings are likely to have clinical relevance for risk grouping, study design, and choice of therapy.

The Impact of DNMT3A Status on NPM1 MRD Predictive Value and Survival in Elderly AML Patients Treated Intensively

Simple Summary

DNMT3A mutation has been associated with adverse outcomes. In this study, we aimed to investigate the impact of DNMT3A status on NPM1 MRD predictive value for survival in a retrospective cohort of acute myeloid leukemia (AML) patients aged over 60 years old treated intensively. A total of 138 patients treated for NPM1-mutated AML in two French institutions were analyzed retrospectively. A 4log reduction of NPM1 MRD was associated with a better outcome. DNMT3A negative patients who achieved a 4log reduction had a superior outcome to those who did not. However, postinduction NPM1 MRD1 reduction was not predictive of OS and LFS in DNMT3Amut patients. These results confirm that post-induction NPM1 MRD1 is a reliable tool to assess disease outcome in elderly AML patients. However, the presence of DNMT3A also identify a subgroup of patients at high risk of relapse.

Abstract

Minimal residual disease (MRD) is now a powerful surrogate marker to assess the response to chemotherapy in acute myeloid leukemia (AML). DNMT3A mutation has been associated with adverse outcomes. In this study, we aimed to investigate the impact of DNMT3A status on NPM1 MRD predictive value for survival in a retrospective cohort of AML patients aged over 60 years old treated intensively. A total of 138 patients treated for NPM1-mutated AML in two French institutions were analyzed retrospectively. DNMT3A status did not influence the probability of having a ≥ 4log MRD1 reduction after induction. Only 20.4% of FLT3-ITD patients reached ≥ 4log MRD1 reduction compared to 47.5% in FLT3wt cases. A 4log reduction of NPM1 MRD was associated with a better outcome, even in FLT3-ITD mutated patients, independent of the allelic ratio. DNMT3A negative patients who reached a 4log reduction had a superior outcome to those who did not (HR = 0.23; p < 0.001). However, postinduction NPM1 MRD1 reduction was not predictive of OS and LFS in DNMT3Amut patients. These results confirm that post-induction NPM1 MRD1 is a reliable tool to assess disease outcome in elderly AML patients. However, the presence of DNMT3A also identifies a subgroup of patients at high risk of relapse.

Strategies targeting FLT3 beyond the kinase inhibitors

Acute myeloid leukemia (AML) is a hematological malignancy characterized by clonal expansion and differentiation arrest of the myeloid progenitor cells, which leads to the accumulation of immature cells called blasts in the bone marrow and peripheral blood. Mutations in the receptor tyrosine kinase FLT3 occur in 30% of normal karyotype patients with AML and are associated with a higher incidence of relapse and worse survival. Targeted therapies against FLT3 mutations using small-molecule FLT3 tyrosine kinase inhibitors (TKIs) have long been investigated, with some showing favorable clinical outcomes. However, major setbacks such as limited clinical efficacy and the high risk of acquired resistance remain unresolved. FLT3 signaling, mutations, and FLT3 inhibitors are topics that have been extensively reviewed in recent years. Strategies to target FLT3 beyond the small molecule kinase inhibitors are expanding, nevertheless they are not receiving enough attention. These modalities include antibody-based FLT3 targeted therapies, immune cells mediated targeting strategies, and approaches targeting downstream signaling pathways and FLT3 translation. Here, we review the most recent advances and the challenges associated with the development of therapeutic modalities targeting FLT3 beyond the kinase inhibitors.

Evaluation of the Anticancer Activity of pH-Sensitive Polyketal Nanoparticles for Acute Myeloid Leukemia

Polyketals are a class of acid-responsive polymers that have been relatively less explored for drug delivery applications compared to polyesters. The degradation of these polymers is accelerated in an acidic medium and does not result in acidic byproducts. Their biocompatibility depends on the diol used for the synthesis. The present work aims to synthesize, characterize, and fabricate nanospheres of an aliphatic polyketal for delivery of the nucleotide analogue cytarabine toward the treatment of acute myeloid leukemia (AML). The internalization mechanism of the nanospheres was probed, and its implication on the nuclear localization and escape from the endo-lysosomal compartments were studied. The drug-loaded polyketal nanoparticles reduced the cell viability to a greater extent compared with the free drug. The effect of the drug-loaded polyketal nanoparticles on the differential gene expression of leukemic cells was investigated for the first time to understand their therapeutic implications. It was found that treatment with drug-loaded polyketal nanoparticles downregulated AML-specific genes involved in cell proliferation and recurrence compared to the free drug. The protein expression studies were performed for selected genes obtained from gene expression analysis. Biodistribution studies showed that the poly(cyclohexane-1,4-diyl acetone dimethylene ketal) (PCADK) nanoparticles exhibit prolonged circulation time. Overall, our results suggest that polyketal-based delivery of cytarabine represents a more effective alternative strategy for AML therapy.

Analysis of FLT3-Activating Mutations in Patients With Acute Myelogenous Leukemia in Jordan: Association With FAB Subtypes and Identification of Subgroups With Poor Prognosis

BACKGROUND

FLT3 mutations are common in acute myeloid leukemia (AML), particularly in French-American-British M2 subtype AML and in cytogenetically normal (CN) AML; however, its incidence in Jordan is poorly studied. An FLT3 mutation implies poor prognosis in AML patients. We aimed to assess the incidence and prognostic value of FLT3 mutations in AML in Jordan.

PATIENTS AND METHODS

One hundred thirty-two newly diagnosed unselected AML patients were included. Patient data were collected, including demographics as well as morphologic, cytogenetic, and molecular testing results. FLT3 mutations were detected by real-time reverse transcriptase PCR, next-generation sequencing, or both. Survival analysis and comparisons of incidence, remission rate, relapse, and survival outcomes between FLT3-mutated and wild-type groups were done and prognostic factors identified.

RESULTS

FLT3 mutation was detected in 40% of AML patients. The highest incidence was associated with M2 subtype AML (47%) and CN-AML (50%). There was a significant negative association between FLT3 mutations and overall survival (OS), as well as a trend toward improved relapse-free survival, with 3-year OS being 19.17% vs 34.16% (P < .0001) and 33.6% vs 71.0% (P = .085), respectively. Patients with FLT3 mutation had a significantly better complete remission rate after induction (67.9% vs 63.3%, P = .001). Also, OS improved in patients with complete remission (P = .0015) and who then continued to allogeneic hematopoietic cell transplantation compared to FLT3 wild-type patients (P < .001).

CONCLUSION

FLT3 mutation is common in Jordanian AML patients, with the highest incidence occurring in patients with M2 or CN disease. It implies a poor prognosis, with poor OS and relapse-free survival, which may be abrogated by early allogeneic transplantation and/or peritransplantation provision of FLT3 inhibitors.

Poor Survival and Differential Impact of Genetic Features of Black Patients with Acute Myeloid Leukemia

Clinical outcome of patients with acute myeloid leukemia (AML) is associated with cytogenetic and molecular factors and patient demographics (e.g., age and race). We compared survival of 25,523 non-Hispanic Black and White adults with AML using Surveillance Epidemiology and End Results (SEER) Program data and performed mutational profiling of 1,339 patients with AML treated on frontline Alliance for Clinical Trials in Oncology (Alliance) protocols. Black patients had shorter survival than White patients, both in SEER and in the setting of Alliance clinical trials. The disparity was especially pronounced in Black patients <60 years, after adjustment for socioeconomic (SEER) and molecular (Alliance) factors. Black race was an independent prognosticator of poor survival. Gene mutation profiles showed fewer NPM1 and more IDH2 mutations in younger Black patients. Overall survival of younger Black patients was adversely affected by IDH2 mutations and FLT3-ITD, but, in contrast to White patients, was not improved by NPM1 mutations. SIGNIFICANCE: We show that young Black patients have not benefited as much as White patients from recent progress in AML treatment in the United States. Our data suggest that both socioeconomic factors and differences in disease biology contribute to the survival disparity and need to be urgently addressed.See related commentary by Vyas, p. 540.This article is highlighted in the In This Issue feature, p. 521.

Global expression of noncoding RNome reveals dysregulation of small RNAs in patients with HTLV-1-associated adult T-cell leukemia: a pilot study

Background

Adult T cell lymphoma/leukemia (ATLL) is a peripheral T-cell neoplasm caused by human T-cell lymphotropic virus-1 (HTLV-1). Small RNAs (sRNAs), including microRNAs (miRNAs), play a pivotal role in the initiation and development of hematological malignancies and may represent potential therapeutic target molecules. However, little is known about how these molecules impact the pathogenesis of ATLL. In this study, we aimed to identify sRNA expression signatures associated with ATLL and to investigate their potential implication in the pathophysiology of the disease.

Methods

Small-RNAseq analysis was performed in peripheral blood mononuclear cells from HTLV-1- associated ATLL (n = 10) in comparison to asymptomatic carriers (n = 8) and healthy controls (n = 5). Sequencing was carried out using the Illumina MiSeq platform, and the deregulation of selected miRNAs was validated by real-time PCR. Pathway analyses of most deregulated miRNA were performed and their global profiling was combined with transcriptome data in ATLL.

Results

The sequencing identified specific sRNAs signatures associated with ATLL patients that target pathways relevant in ATLL, such as the transforming growth factor-(βTGF-β), Wnt, p53, apoptosis, and mitogen-activated protein kinase (MAPK) signaling cascades. Network analysis revealed several miRNAs regulating highly connected genes within the ATLL transcriptome. miR-451-3p was the most downregulated miRNA in active patients.

Conclusions

Our findings shed light on the expression of specific sRNAs in HTLV-1 associated ATLL, which may represent promising candidates as biomarkers that help monitor the disease activity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13027-020-00343-2.

Lomustine is beneficial to older AML with ELN2017 adverse risk profile and intermediate karyotype: a FILO study

We previously reported the benefit of lomustine addition to conventional chemotherapy in older acute myeloid leukemias with nonadverse chromosomal aberrations in the LAM-SA 2007 randomized clinical trial (NCT00590837). A molecular analysis of 52 genes performed in 330 patients included in this trial, 163 patients being treated with lomustine in combination with idarubicin and cytarabine and 167 without lomustine, identified 1088 mutations with an average of 3.3 mutations per patient. NPM1, FLT3, and DNMT3A were the most frequently mutated genes. A putative therapeutic target was identified in 178 patients (54%). Among five molecular classifications analyzed, the ELN2017 risk classification has the stronger association with the clinical evolution. Patients not treated with lomustine have an expected survival prognosis in agreement with this classification regarding the overall and event-free survivals. In strong contrast, lomustine erased the ELN2017 classification prognosis. The benefit of lomustine in nonadverse chromosomal aberrations was restricted to patients with RUNX1, ASXL1, TP53, and FLT3-ITD^high/NPM1^WT mutations in contrast to the intermediate and favorable ELN2017 patients. This post-hoc analysis identified a subgroup of fit elderly AML patients with intermediate cytogenetics and molecular markers who may benefit from lomustine addition to intensive chemotherapy.

Practical Considerations for Treatment of Relapsed/Refractory FLT3-ITD Acute Myeloid Leukaemia with Quizartinib: Illustrative Case Reports

Quizartinib is a tyrosine kinase inhibitor selectively targeting the FMS-like tyrosine kinase 3 (FLT3) receptor that has been developed for the treatment of acute myeloid leukaemia (AML). The Phase 3 QuANTUM-R study investigated the efficacy of quizartinib monotherapy in patients with relapsed/refractory FLT3-ITD mutation-positive AML. The clinical course of four QuANTUM-R participants exemplifies issues specific to quizartinib treatment and is described here. Patient 1 was FLT3-ITD mutation-negative at AML diagnosis, but became FLT3-ITD mutation-positive during treatment that included several lines of chemotherapy and was therefore a suitable candidate for quizartinib. Because of the clonal shifts of AML during treatment, retesting genetic alterations at each relapse or resistance may help to identify candidates for targeted treatment options. Patient 2 developed QTc prolongation during quizartinib treatment, but the QTc interval normalised after dose reduction, allowing the patient to continue treatment and eventually resume the recommended dose. Patient 3 responded to quizartinib and was scheduled for haematopoietic stem cell transplant (HSCT), but developed febrile neutropenia and invasive aspergillosis during conditioning and subsequently died (to avoid drug-drug interactions, no azole antifungal was administered concomitantly). Care is required when selecting concomitant medications, and if there is potential for interactions (e.g. if prophylactic azole antifungals are required) the quizartinib dose should be reduced to minimise the risk of QTc prolongation. Patient 4 was able to undergo HSCT after responding to quizartinib and experienced a durable response after HSCT while on quizartinib maintenance therapy. Together, these cases illustrate the main issues to be addressed when managing patients under quizartinib, allowing for adequate scheduling and tolerability, bridging to HSCT, and durable remission on maintenance therapy in some patients.

Genomic markers of midostaurin drug sensitivity in FLT3 mutated and FLT3 wild-type acute myeloid leukemia patients

Acute myeloid leukemia (AML) is a heterogeneous malignancy with the most common genomic alterations in NPM1, DNMT3A, and FLT3. Midostaurin was the first FLT3 inhibitor FDA approved for AML and is standard of care for FLT3 mutant patients undergoing induction chemotherapy [1, 2]. As there is a spectrum of response, we hypothesized that biological factors beyond FLT3 could play a role in drug sensitivity and that select FLT3-ITD negative samples may also demonstrate sensitivity. Thus, we aimed to identify features that would predict response to midostaurin in FLT3 mutant and wild-type samples. We performed an ex vivo drug sensitivity screen on primary and relapsed AML samples with corresponding targeted sequencing and RNA sequencing. We observed a correlation between FLT3-ITD mutations and midostaurin sensitivity as expected and observed KRAS and TP53 mutations correlating with midostaurin resistance in FLT3-ITD negative samples. Further, we identified genes differentially expressed in sensitive vs. resistant samples independent of FLT3-ITD status. Within FLT3-ITD mutant samples, over-expression of RGL4, oncogene and regulator of the Ras-Raf-MEK-ERK cascade, distinguished resistant from sensitive samples. Overall, this study highlights the complexity underlying midostaurin response. And, our results suggest that therapies that target both FLT3 and MAPK/ERK signaling may help circumvent some cases of resistance.

Small RNA profiles of HTLV-1 asymptomatic carriers with monoclonal and polyclonal rearrangement of the T-cell antigen receptor γ-chain using massively parallel sequencing: A pilot study

In the present pilot study, massively parallel sequencing (MPS) technology was used to investigate cellular small RNA (sRNA) levels in the peripheral blood mononuclear cells (PBMCs) of human T-lymphotropic virus type I (HTLV–I) infected asymptomatic carriers with monoclonal (ASM) and polyclonal (ASP) T cell receptor (TCR) γ gene. Blood samples from 15 HTLV–I asymptomatic carriers (seven ASM and eight ASP) were tested for the clonal TCR-γ gene and submitted for sRNA library construction together with blood samples of five healthy controls (HCs) using Illumina sequencing platform. The sRNA-sequencing reads were aligned, annotated and profiled using various bioinformatics tools. Based on these results, possible markers were validated in the study samples by performing reverse transcription-quantitative (RT-q)PCR analysis. A total of 76 known sRNAs and 52 putative novel sRNAs were identified. Among them, 44 known and 34 potential novel sRNAs were differentially expressed in the ASM and ASP libraries compared with HCs. In addition, 10 known sRNAs were exclusively dysregulated in the ASM group and one (transfer RNA 65) was significantly upregulated in the ASP group. Homo sapiens (hsa) microRNA (miRNA/mir)-23a-3p, −28-5p, hsa-let-7e-5p and hsa-mir-28-3p and −361-5p were the most abundantly upregulated mature miRNAs and hsa-mir-363-3p, −532-5p, −106a-5p, −25-3p and −30e-5p were significantly downregulated miRNAs (P<0.05) with a >2-fold difference between the ASM and ASP groups compared with HCs. Based on these results, hsa-mir-23a-3p and −363-3p were selected for additional validation. However, the quantification of these two miRNAs using RT-qPCR did not provide any significant differences. While the present study failed to identify predictive sRNA markers to distinguish between ASM and ASP, the MPS results revealed differential sRNA expression profiles in the PBMCs of HTLV-1 asymptomatic carriers (ASM and ASP) compared with HCs.

Gilteritinib in the treatment of relapsed and refractory acute myeloid leukemia with a FLT3 mutation

Acute myeloid leukemia (AML) is a malignancy of uncontrolled proliferation of immature myeloid blasts characterized by clonal evolution and genetic heterogeneity. FMS-like tyrosine kinase 3 (FLT3) mutations occur in up to a third of AML cases and are associated with highly proliferative disease, shorter duration of remission, and increased rates of disease relapse. The known impact of activating mutations in FLT3 in AML on disease pathogenesis, prognosis, and response to therapy has led to the development of tyrosine kinase inhibitors targeting FLT3. Gilteritinib is a potent, second generation inhibitor of both FLT3 and AXL, designed to address the limitations of other FLT3 inhibitors, particularly in targeting mechanisms of resistance to other drugs. In this review, we present comprehensive data on recent and ongoing studies evaluating the role of gilteritinib in the relapsed and refractory FLT3 mutated AML setting.

Emerging pharmacotherapies for elderly acute myeloid leukemia patients

INTRODUCTION

Acute myeloid leukemia (AML) is a disease mainly seen in the elderly, for which treatment is undergoing rapid changes. Although recent studies have supported the survival benefit of induction chemotherapy in fit patients and that of hypomethylating agents (HMAs) in non-induction candidates, treatment of this patient age population remains a significant challenge for the treating oncologist.

AREAS COVERED

In this review, we will examine effectiveness and safety outcomes of upcoming novel treatment strategies in elderly (≥60 years old) patients with AML, highlight the current literature and ongoing trials able to maximize therapeutic options in this heterogeneous patient population.

EXPERT OPINION

Current developments including new chemotherapeutic strategies and combinations of HMAs with novel drugs targeting epigenetic or immunomodulatory pathways are underway to improve patient survival and quality of life.

MiR-144: A New Possible Therapeutic Target and Diagnostic/Prognostic Tool in Cancers

MicroRNAs (miRNAs) are small and non-coding RNAs that display aberrant expression in the tissue and plasma of cancer patients when tested in comparison to healthy individuals. In past decades, research data proposed that miRNAs could be diagnostic and prognostic biomarkers in cancer patients. It has been confirmed that miRNAs can act either as oncogenes by silencing tumor inhibitors or as tumor suppressors by targeting oncoproteins. MiR-144s are located in the chromosomal region 17q11.2, which is subject to significant damage in many types of cancers. In this review, we assess the involvement of miR-144s in several cancer types by illustrating the possible target genes that are related to each cancer, and we also briefly describe the clinical applications of miR-144s as a diagnostic and prognostic tool in cancers.

Comprehensive diagnostics of acute myeloid leukemia by whole transcriptome RNA sequencing

Acute myeloid leukemia (AML) is caused by genetic aberrations that also govern the prognosis of patients and guide risk-adapted and targeted therapy. Genetic aberrations in AML are structurally diverse and currently detected by different diagnostic assays. This study sought to establish whole transcriptome RNA sequencing as single, comprehensive, and flexible platform for AML diagnostics. We developed HAMLET (Human AML Expedited Transcriptomics) as bioinformatics pipeline for simultaneous detection of fusion genes, small variants, tandem duplications, and gene expression with all information assembled in an annotated, user-friendly output file. Whole transcriptome RNA sequencing was performed on 100 AML cases and HAMLET results were validated by reference assays and targeted resequencing. The data showed that HAMLET accurately detected all fusion genes and overexpression of EVI1 irrespective of 3q26 aberrations. In addition, small variants in 13 genes that are often mutated in AML were called with 99.2% sensitivity and 100% specificity, and tandem duplications in FLT3 and KMT2A were detected by a novel algorithm based on soft-clipped reads with 100% sensitivity and 97.1% specificity. In conclusion, HAMLET has the potential to provide accurate comprehensive diagnostic information relevant for AML classification, risk assessment and targeted therapy on a single technology platform.

microRNA-144 inhibits cell proliferation and invasion by directly targeting TIGAR in esophageal carcinoma

microRNAs (miRNAs) have been identified to play vital roles in the development and progression of numerous different types of human malignancy, including esophageal squamous cell carcinoma (ESCC). In the present study, the biological function of microRNA-144 (miR-144) was investigated, as well as its underlying molecular mechanism in ESCC. The results revealed that miR-144 expression was significantly decreased, whereas the expression of TP53-inducible glycolysis and apoptosis regulator (TIGAR) was significantly increased in human ESCC tissues when compared with adjacent non-tumor tissues. An increase in TIGAR was significantly associated with tumor size and Tumor-Node-Metastasis staging in patients. Functional analysis revealed that the overexpression of miR-144 using lentivirus particles significantly inhibited cell proliferation and tumor colony formation, and induced cell apoptosis in EC9706 and EC109 cells. The autophagy activity was also enhanced by miR-144 activity. In addition, overexpression of miR-144 significantly inhibited tumor growth in vivo. In the present study, TIGAR was confirmed to be the downstream target of miR-144 in ESCC. siRNA-mediated downregulation of TIGAR inversely regulated the inhibition effect of miR-144 on ESCC cells. To conclude, the present study demonstrated that miR-144 inhibits proliferation and invasion in esophageal cancer by directly targeting TIGAR.

Profile of Quizartinib for the Treatment of Adult Patients with Relapsed/Refractory FLT3-ITD-Positive Acute Myeloid Leukemia: Evidence to Date

Acute myeloid leukemia (AML) is a clonal hematologic neoplasm characterized by rapid, uncontrolled cell growth of immature myeloid cells (blasts). There are numerous genetic abnormalities in AML, many of which are prognostic, but an increasing number are targets for drug therapy. One of the most common genetic abnormalities in AML are activating mutations in the FMS-like tyrosine kinase 3 receptor (FLT3). As a receptor tyrosine kinase, FLT3 was the first targetable genetic abnormality in AML. The first generation of FLT3 inhibitors were broad-spectrum kinase inhibitors that inhibited FLT3 among other proteins. Although clinically active, first-generation FLT3 inhibitors had limited success as single agents. This led to the development of a second generation of more selective FLT3 inhibitors. This review focuses on quizartinib, a potent second-generation FLT3 inhibitor. We discuss the clinical trial development, mechanisms of resistance, and the recent FDA decision to deny approval for quizartinib as a single agent in relapsed/refractory AML.

A novel circular RNA (hsa_circ_0000370) increases cell viability and inhibits apoptosis of FLT3-ITD-positive acute myeloid leukemia cells by regulating miR-1299 and S100A7A

FLT3-ITD⁺ acute myeloid leukemia (AML) is an important subtype of AML, accounting for approximately 25 % of all AML cases in the world. Recently, increasing evidence has shown that circular RNAs (circRNAs) can act as effective biomarkers of various human cancers. However, the roles of circRNAs in AML remain largely unclear. In the present study, circ_0000370 was found to be significantly increased in FLT3-ITD⁺ AML and was demonstrated to act as an oncogenic circRNA of AML in vitro. TargetScan results showed that miR-1299, miR-370-3p, miR-502-5p, miR-1281 and miR-640 were potential targets of circ_0000370, and miR-1299 had the broadest range of interactome compared with other microRNAs of interest. Moreover, we demonstrated that S100A7A was a target gene of miR-1299, and circ_0000370 could regulate S100A7A expression by sponging miR-1299 in AML cell lines. Therefore, we suggest that the promoting effects of circ_0000370 on the progression of FLT3-ITD⁺ AML might be relevant to the inhibition of miR-1299 and the upregulation of S100A7A.

The Interplay Between the Genetic and Immune Landscapes of AML: Mechanisms and Implications for Risk Stratification and Therapy

AML holds a unique place in the history of immunotherapy by virtue of being among the first malignancies in which durable remissions were achieved with "adoptive immunotherapy," now known as allogeneic stem cell transplantation. The successful deployment of unselected adoptive cell therapy established AML as a disease responsive to immunomodulation. Classification systems for AML have been refined and expanded over the years in an effort to capture the variability of this heterogeneous disease and risk-stratify patients. Current systems increasingly incorporate information about cytogenetic alterations and genetic mutations. The advent of next generation sequencing technology has enabled the comprehensive identification of recurrent genetic mutations, many with predictive power. Recurrent genetic mutations found in AML have been intensely studied from a cell intrinsic perspective leading to the genesis of multiple, recently approved targeted therapies including IDH1/2-mutant inhibitors and FLT3-ITD/-TKD inhibitors. However, there is a paucity of data on the effects of these targeted agents on the leukemia microenvironment, including the immune system. Recently, the phenomenal success of checkpoint inhibitors and CAR-T cells has re-ignited interest in understanding the mechanisms leading to immune dysregulation and suppression in leukemia, with the objective of harnessing the power of the immune system via novel immunotherapeutics. A paradigm has emerged that places crosstalk with the immune system at the crux of any effective therapy. Ongoing research will reveal how AML genetics inform the composition of the immune microenvironment paving the way for personalized immunotherapy.

A retrospective study of the correlation of in vitro chemosensitivity using ATP-TCA with patient clinical outcomes in acute myeloid leukemia

PURPOSE

To evaluate the predictive value of the in vitro chemosensitivity using ATP-TCA method to compare the clinical efficacy of patients with AML.

METHODS

Bone marrow or peripheral blood samples were collected from 65 patients with AML, and the in vitro chemosensitivity of four drugs (cytarabine/idarubicin/decitabine/aclacinomycin) was measured by an ATP-tumor chemosensitivity assay.

RESULTS

Aclacinomycin and cytarabine had the highest chemosensitivity rates (66.7%, 8/12 and 58.5%, 38/65, respectively), while idarubicin and decitabine had rates of 6.5% (3/46) and 0% (0/35), respectively. Complete remission (CR) was achieved in 66.2% (43/65) of patients, and there was a statistically significant correlation between CR and in vitro chemosensitivity for cytarabine (47.7% vs 18.5%, p = 0.002), but not for the anthracyclines (p = 0.950). In addition, three other factors significantly correlated with CR: disease status (p = 0.005), FLT3-ITD/TKD mutation (p = 0.003) and chemotherapy regimens (p = 0.004). Furthermore, multiple logistic regression analysis revealed that the sensitivity of cytarabine was one of the significant risk factors for CR [hazard ratio (HR) = 5.52; 95% confidence interval (CI) = 1.47-20.70; p = 0.011].

CONCLUSIONS

The in vitro chemosensitivity as tested by ATP-TCA demonstrated a significant correlation with CR for chemotherapy and can be a useful tool to optimize personalized treatments for patients with AML.

Quizartinib in the treatment of FLT3-internal-tandem duplication-positive acute myeloid leukemia

FLT3 mutations, characterized by an internal-tandem duplication or missense mutations in the tyrosine kinase domain, are observed in a third of patients with newly diagnosed acute myeloid leukemia. FLT3-ITD mutations are associated with high relapse rates and short overall survival with conventional chemotherapy. Several tyrosine kinase inhibitors targeting FLT3 have been developed in an effort to improve survival and therapeutic options. This review focuses on quizartinib, a second-generation FLT3 inhibitor that has demonstrated efficacy and safety as a single agent and in combination with chemotherapy. We discuss its clinical development as well as its place in the treatment of FLT3-mutated acute myeloid leukemia among the other FLT3 inhibtors currently available and its mechanisms of resistance.

8-chloro-adenosine activity in FLT3-ITD acute myeloid leukemia

Nucleoside analogs represent the backbone of several distinct chemotherapy regimens for acute myeloid leukemia (AML) and combination with tyrosine kinase inhibitors has improved survival of AML patients, including those harboring the poor-risk FLT3-ITD mutation. Although these compounds are effective in killing proliferating blasts, they lack activity against quiescent leukemia stem cells (LSCs), which contributes to initial treatment refractoriness or subsequent disease relapse. The reagent 8-chloro-adenosine (8-Cl-Ado) is a ribose-containing, RNA-directed nucleoside analog that is incorporated into newly transcribed RNA rather than in DNA, causing inhibition of RNA transcription. In this report, we demonstrate antileukemic activities of 8-Cl-Ado in vitro and in vivo and provide mechanistic insight into the mode of action of 8-Cl-Ado in AML. 8-Cl-Ado markedly induced apoptosis in LSC, with negligible effects on normal stem cells. 8-Cl-Ado was particularly effective against AML cell lines and primary AML blast cells harboring the FLT3-ITD mutation. FLT3-ITD is associated with high expression of miR-155. Furthermore, we demonstrate that 8-Cl-Ado inhibits miR-155 expression levels accompanied by induction of DNA-damage and suppression of cell proliferation, through regulation of miR-155/ErbB3 binding protein 1(Ebp1)/p53/PCNA signaling. Finally, we determined that combined treatment of NSG mice engrafted with FLT3-ITD + MV4-11 AML cells with 8-Cl-Ado and the FLT3 inhibitor AC220 (quizartinib) synergistically enhanced survival, compared with that of mice treated with the individual drugs, suggesting a potentially effective approach for FLT3-ITD AML patients.

Scutellaria barbata D. Don (SBD) protects oxygen glucose deprivation/reperfusion-induced injuries of PC12 cells by up-regulating Nrf2

This study aimed to investigate the potential effect of Scutellaria barbata D. Don (SBD) on oxygen glucose deprivation/reperfusion (OGD/R)-injured PC12 cells. PC12 cells were pretreated with various concentrations of 0.1-0.8 mg/ml SBD for indicated times (12-48 h) and then subjected to OGD/R injury. Cell viability, apoptosis and proliferation were detected using MTT assay, flow cytometry, Ki67 staining and western blot. Oxidative damage was assessed by detecting MDA content, SOD activity and GSH levels. The mitochondrial membrane potential (Δψm) was measured by Rh123 staining. Western blot was performed to assess the expression levels of Nrf2 and PI3K/AKT pathway-related proteins. We found that SBD pretreatment promoted cell viability and proliferation but inhibited apoptosis of OGD/R-injured PC12 cells in dosage- and time-dependent manner. Meanwhile, SBD attenuated oxidative damage and restored mitochondria dysfunction, as evidenced by the reduced MDA content, the increased SOD and GSH levels, and the increased Δψm. Furthermore, SBD induced the expression of Nrf2 in a PI3K/AKT-dependent signalling. Knockdown of Nrf2 blocked the protective effects of SBD on PC12 cells. In conclusion, this study demonstrates that SBD pretreatment protects PC12 cells against OGD/R-induced injury. The potential mechanism may be through up-regulating the expression of Nrf2 in a PI3K/AKT-dependent pathway.

Targeting Tyrosine Kinases in Acute Myeloid Leukemia: Why, Who and How?

Acute myeloid leukemia (AML) is a myeloid malignancy carrying a heterogeneous molecular panel of mutations participating in the blockade of differentiation and the increased proliferation of myeloid hematopoietic stem and progenitor cells. The historical "3 + 7" treatment (cytarabine and daunorubicin) is currently challenged by new therapeutic strategies, including drugs depending on the molecular landscape of AML. This panel of mutations makes it possible to combine some of these new treatments with conventional chemotherapy. For example, the FLT3 receptor is overexpressed or mutated in 80% or 30% of AML, respectively. Such anomalies have led to the development of targeted therapies using tyrosine kinase inhibitors (TKIs). In this review, we document the history of TKI targeting, FLT3 and several other tyrosine kinases involved in dysregulated signaling pathways.

A comprehensive review on miR-451: A promising cancer biomarker with therapeutic potential

MicroRNAs (miRNAs) are proposed as a family of short noncoding molecules able to manage and control the expression of the gene targets at the posttranscriptional level. They contribute in several fundamental physiological mechanisms as well as a verity of human and animal diseases such as cancer progression. Among these tiny RNAs, miR-451 placed on chromosome 17 at 17q11.2 presents an essential role in many biological processes in health condition and also in pathogenesis of different diseases. Besides, it has been recently considered as a valuable biomarker for cancer detection, prognosis and treatment. Therefore, this review will provide the critical functions of miR-451 on biological mechanisms including cell cycle and proliferation, cell survival and apoptosis, differentiation and development as well as disease initiation and progression such as tumor formation, migration, invasion, and metastasis.

Ailanthone up-regulates miR-449a to restrain acute myeloid leukemia cells growth, migration and invasion

BACKGROUND

Ailanthone (AIL) is a quassinoid isolated from traditional Chinese herbal medicine Ailanthus altissima. The anti-tumor activities of AIL have been reported in various solid tumors. This study aimed to reveal the in vitro effect of AIL on acute myeloid leukemia (AML) cells.

METHODS

The effects of AIL on five AML cell lines (KG1, HL60, U-937, THP-1 and OCI-AML2) as well as myeloid progenitor cells were evaluated by performing CCK-8 assay, flow cytometry, Transwell assay and Western blotting. KG1 and HL60 cells were transfected with miR-449a inhibitor or its negative control, and then were treated by AIL. The above mentioned assays were performed again to study the involvement of miR-449a in AIL's function.

RESULTS

AIL dose-dependently inhibited the viability of AML cells and myeloid progenitor cells. The IC50 value of AIL towards KG1 and HL60 cells was 0.58 and 0.57 μM, respectively. AIL with concentration of 0.5 μM significantly induced the apoptosis of AML cells rather than myeloid progenitor cells. Meanwhile, 0.5 μM AIL significantly reduced migration and invasion of AML cells. miR-449a was highly expressed in response to the treatment of 0.5 μM AIL. Besides this, the anti-tumor activities of AIL in AML cells were attenuated by miR-449a silence. Further, the blockage of Notch and PI3K/AKT signaling pathways induced by AIL was reversed by miR-449a silence.

CONCLUSION

AIL restrained AML cells growth, migration and invasion through up-regulation of miR-449a, and deactivation of Notch and PI3K/AKT signaling pathways.

Clinical Effect of Combined Mutations in DNMT3A, FLT3-ITD, and NPM1 Among Egyptian Acute Myeloid Leukemia Patients

BACKGROUND

Genotypic mutation of fms like tyrosine kinase 3 (FLT3), Nucleophosmin (NPM1), and DNA-methyltransferase 3A (DNMT3A) has been involved in the leukemogenesis of acute myeloid leukemia (AML), with the well known poor prognostic role of FLT3 and DNMT3A and favorable role for the NPM1 mutation.

PATIENTS AND METHODS

A total of 123 patients with AML treated at the National Cancer Institute, Cairo University were examined for mutations in DNMT3A, FLT3, and NPM1 using polymerase chain reaction (PCR) for detecting FLT3 internal tandem duplication (ITD) and allele-specific PCR to detect DNMT3A and NPM1A mutations. Two-way direct sequencing and Gene Mapper version 4.0 software (Fred Hutchinson Cancer Research Center) sequencing were used as confirmatory tests for DNMT3A and NPM1A mutations, respectively.

RESULTS

DNMT3A, FLT3-ITD, and NPM1A gene mutations were detected in 22 (17.9%), 22 (17.9%), and 24 (19.5%) patients, respectively. DNMT3A/FLT3, NPM1A/FLT3, and DNMT3A/NPM1A combined mutant genotypes were detected in 5 (4.1%), 9 (7.3%), and 3 (2.4%) patients, respectively. Two patients (1.6%) had triple mutant genotypes (DNMT3A/FLT3/NPM1A). FLT3 and DNMT3A mutations had a significant negative effect on complete response (CR) rates (P = .016). FLT3-ITD mutation was significantly associated with older age (P = .029), and lower overall survival (OS) rates (P = .046). DNMT3A/FLT3 combined mutant genotypes were significantly associated with a lower OS rate (P = .016). Mutant NPM1/wild type FLT3, wild type DNMT3A/FLT3, and mutant NPM1A/wild type DNMT3A combinations were significantly associated with higher CR rates (P = .006, P = .006, and P = .023, respectively).

CONCLUSION

DNMT3A, FLT3-ITD, and NPM1A are frequent mutations in Egyptian AML. FLT3-ITD mutations are frequent in older patients. DNMT3A and FLT3-ITD mutations were associated with an unfavorable prognosis, but the NPM1A mutation has tendency to indicate a good prognosis.

Myelodysplastic syndromes and acute myeloid leukemias in the elderly

Most patients above 60 years with acute myeloid leukemia (AML) will die from their disease. Nevertheless, the treatment concepts in elderly patients with myelodysplastic syndromes (MDS) and AML are rapidly evolving. A number of recent reports have identified better survival rates with intensive induction chemotherapy for patients up to 80 years, with the exception of patients with unfavorable genomic risk abnormalities or with major co-morbidities. Gemtuzumab ozogamicin is increasingly added to induction therapy for AML patients up to 70 years with favorable or intermediate risk profile, and Midostaurin for patients with a FLT3 mutation. The recommended dose of daunorubicin is 60 mg/m² for 3 + 7 induction therapy. Elderly patients with acute promyelocytic leukemia should receive all-trans retinoic acid and arsenic trioxide, and cytotoxic treatment is limited upfront to patients with initial leukocytosis. Allogeneic transplantation can be recommended to selected patients up to 70-75 years. For patients unfit for intensive treatment, therapeutic options comprise a hypomethylating agent (HMA), low-dose cytarabin and supportive care. HMA treatment is also increasingly applied for relapsed/refractory AML after intensive chemotherapy. A considerable number of candidate compounds are currently being studied in older AML patients, with their potential role in the treatment of elderly AML patients remaining to be clarified.

Allogeneic Hematopoietic Stem Cell Transplantation for Older Patients With Acute Myeloid Leukemia

OPINION STATEMENT

Acute myelogenous leukemia (AML) in the elderly is complex and has a poor prognosis, often characterized by higher risk cytogenetic and molecular features compared to that in younger patients. Rates of transplant have been limited by concern related to non-relapse mortality, as older patients have historically been considered medically unfit for the transplantation process. Reduced-intensity conditioning (RIC) for hematopoietic stem cell transplantation (HSCT) has been shown to provide similar efficacy to myeloablative methods, with decreased non-relapse mortality in the elderly and improved efficacy over non-transplant approaches with cytotoxic chemotherapy alone. Targeted non-cytotoxic and modified cytotoxic agents have emerged to further improve transplant outcomes for older AML patients. Validated comorbidity indices are useful tools to assess an individual's fitness for undergoing HSCT rather than chronological age alone. We believe HSCT is the primary curative treatment approach for many older AML patients, taking into account risk and comorbidities, particularly given the tendency of leukemia in this population to harbor an unfavorable disease profile. We use RIC and advocate for the addition of targeted agents if applicable. With continuing data in support of transplant for older AML patients, we anticipate that transplant rates in this population will continue to rise.

Targeting Oncogenic Signaling in Mutant FLT3 Acute Myeloid Leukemia: The Path to Least Resistance

The identification of recurrent driver mutations in genes encoding tyrosine kinases has resulted in the development of molecularly-targeted treatment strategies designed to improve outcomes for patients diagnosed with acute myeloid leukemia (AML). The receptor tyrosine kinase FLT3 is the most commonly mutated gene in AML, with internal tandem duplications within the juxtamembrane domain (FLT3-ITD) or missense mutations in the tyrosine kinase domain (FLT3-TKD) present in 30–35% of AML patients at diagnosis. An established driver mutation and marker of poor prognosis, the FLT3 tyrosine kinase has emerged as an attractive therapeutic target, and thus, encouraged the development of FLT3 tyrosine kinase inhibitors (TKIs). However, the therapeutic benefit of FLT3 inhibition, particularly as a monotherapy, frequently results in the development of treatment resistance and disease relapse. Commonly, FLT3 inhibitor resistance occurs by the emergence of secondary lesions in the FLT3 gene, particularly in the second tyrosine kinase domain (TKD) at residue Asp835 (D835) to form a ‘dual mutation’ (ITD-D835). Individual FLT3-ITD and FLT3-TKD mutations influence independent signaling cascades; however, little is known about which divergent signaling pathways are controlled by each of the FLT3 specific mutations, particularly in the context of patients harboring dual ITD-D835 mutations. This review provides a comprehensive analysis of the known discrete and cooperative signaling pathways deregulated by each of the FLT3 specific mutations, as well as the therapeutic approaches that hold the most promise of more durable and personalized therapeutic approaches to improve treatments of FLT3 mutant AML.

Sorafenib Combined with 5-azacytidine in Older Patients with Untreated FLT3-ITD Mutated Acute Myeloid Leukemia

Based on our previous study of the combination of sorafenib with 5-azacytidine (AZA) in relapsed/refractory patients with FLT3 mutated acute myeloid leukemia (AML), we hypothesized that the combination would be efficacious and well tolerated in untreated patients with FLT3 mutated AML who are unsuitable for standard chemotherapy due to advanced age or lack of fitness. Newly diagnosed patients with untreated FLT3 mutated AML who underwent frontline therapy on 2 separate protocols of AZA plus sorafenib were analyzed. The clinical trials were registered at clinicaltrials.gov (NCT02196857 and NCT01254890). Overall, 27 patients with untreated FLT3 mutated AML (median age of 74 years, range, 61-86) were enrolled. The overall response rate was 78% (7 [26%] CR, 12 [44%] CRi/CRp, and 2 [7%] PR). Patients received a median of 3 treatment cycles (1-35). The median duration of CR/CRp/CRi is 14.5 months (1.1-28.7 months). Three (11%) responding patients (1 CR, 2 CRi) proceeded to allogeneic stem cell transplant. The median follow-up for surviving patients was 4.1 months (3.0-17.3 months). The median overall survival for the entire group was 8.3 months, and 9.2 months in the 19 responders. The regimen was well tolerated in elderly patients with untreated FLT3 mutated AML with no early deaths.