Molecular genetics of adult acute myeloid leukemia: prognostic and therapeutic implications

Immunotherapy-Based Targeting and Elimination of Leukemic Stem Cells in AML and CML

The concept of leukemic stem cells (LSC) has been developed with the idea to explain the clonal hierarchies and architectures in leukemia, and the more or less curative anti-neoplastic effects of various targeted drugs. It is now widely accepted that curative therapies must have the potential to eliminate or completely suppress LSC, as only these cells can restore and propagate the malignancy for unlimited time periods. Since LSC represent a minor cell fraction in the leukemic clone, little is known about their properties and target expression profiles. Over the past few years, several cell-specific immunotherapy concepts have been developed, including new generations of cell-targeting antibodies, antibody-toxin conjugates, bispecific antibodies, and CAR-T cell-based strategies. Whereas such concepts have been translated and may improve outcomes of therapy in certain lymphoid neoplasms and a few other malignancies, only little is known about immunological targets that are clinically relevant and can be employed to establish such therapies in myeloid neoplasms. In the current article, we provide an overview of the immunologically relevant molecular targets expressed on LSC in patients with acute myeloid leukemia (AML) and chronic myeloid leukemia (CML). In addition, we discuss the current status of antibody-based therapies in these malignancies, their mode of action, and successful examples from the field.

TET2 Single Nucleotide Polymorphism in Myeloid Neoplasms Among Egyptian Patients

Acute myelogenous leukemia (AML) is a heterogeneous disease characterized by myeloid progenitor cells uncontrolled proliferation gradually replacing normal hematopoiesis. To evaluate Ten Eleven Translocation 2 gene (TET2) single nucleotide polymorphism (SNP) (rs2454206, rs34402524, rs61744960) in AML, and chronic myeloid leukemia (CML) in relation to their disease prognostic criteria. The study included 136 subjects; 52 AML, 54 CML and 30 subjects as control group matched for age and sex. Routine investigations including CBC, bone marrow aspiration, flow cytometry biochemical investigations and cytogenetics and molecular study were performed accordingly. DNA extraction and SNP assay for TET2 gene polymorphism was done using (Thermo-Fisher predesigned SNP, USA) PCR prism 7500. The mean age was 43.4 ± 14.0 years in AML patients, 45.98 ± 15.7 years in CML patients and 39.3 ± 6.587 years in control group (p > 0.05). The frequency of TET2 SNP rs 34402524 ranged from heterozygous to homozygous in both AML (46%, 54%) and CML (48%, 46.2%) groups but was mainly homozygous among the control (80%) group (p = 0.012). TET2 SNP rs 2454206 was mainly wild in CML (65.4%) and control (63.3%) groups compared to AML as wild was only in (46%) and heterozygous in (44%) with only 10% being homozygous (p = 0.046). TET2 SNP rs 61744960 showed a homozygous pattern among all three group (AML CML and control) showing no statistical significance (p = 0.528). Eventhough, higher non responders to treatment were among homozygous and heterozygous groups yet, response to therapy as respect to specific TET2 SNP showed no significant variation (p > 0.05). TET2 SNP in CML cases did not alter the prognostic criteria as no statistical significance was noted (p > 0.05) except for TET2 SNP rs 34402524 where homozygous cases had larger spleen size (p = 0.019). TET2 SNP is common in Egyptian myeloid neoplasm. This is the first study in this field and further studies are recommended to investigate TET2 and relation to other hematological malignancies and leukemogenesis transformation.

A six-gene-based prognostic model predicts complete remission and overall survival in childhood acute myeloid leukemia

Objective

Acute myeloid leukemia (AML) is a malignant clonal disorder. Despite enormous progress in its diagnosis and treatment, the mortality rate of AML remains high. The aim of this study was to identify prognostic biomarkers by using the gene expression profile dataset from public database, and to improve the risk-stratification criteria of survival for patients with AML.

Materials and methods

The gene expression data and clinical parameter were acquired from the Therapeutically Applicable Research to Generate Effective Treatment (TARGET) database. A total of 856 differentially expressed genes (DEGs) were obtained from the childhood AML patients classified into first complete remission (CR1) group (n=791) and not CR group (n=249). We performed a series of bioinformatics analysis to screen key genes and pathways, further comprehending these DEGs through Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses.

Results

Six genes (SLC17A7, MSX2, CDC26, MSLN, CTSZ and DEFA3) identified by univariate, Kaplan-Meier survival and multivariate Cox regression analyses were used to develop the prognostic model. Further analysis showed that the survival estimations in the high-risk group had an increased risk of death compared with the low-risk group based on the model. The area under the curve of the receiver operator characteristic curve in the prognostic model for predicting the overall survival was 0.729, confirming good prognostic model. We also performed a nomogram to provide an individual patient with the overall probability, and internal validation in the TARGET cohort.

Conclusion

We identified a six-gene prognostic signature for risk-stratifying in patients with childhood AML. The risk classification model can be used to predict CR markers and may assist clinicians in providing realize the individualized treatment in this patient population.

Identification of High-Affinity Small Molecule Targeting IDH2 for the Clinical Treatment of Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is symbolized by an increase in the number of myeloid cells in the bone marrow and an arrest in their maturation, frequently resulting in hematopoietic insufficiency (granulocytopenia, thrombocytopenia, or anemia) with or without leukocytosis either by a predominance of immature forms or a loss of normal hematopoiesis. IDH2 gene encodes for isocitrate dehydrogenase enzyme which is involved in the TCA cycle domino effect and converts isocitrate to alpha-ketoglutarate. In the U.S, the annual incidence of AML progressively increases with age to a peak of 12.6 per 100,000 adults of 65 years or older. Mutations in isocitrate dehydrogenase 2 (arginine 132) have been demonstrated to be recurrent gene alterations in acute myeloid leukemia (AML) by forming 2-Hydroxy alpha ketoglutarate which, instead of participating in TCA cycle, accumulates to form AML. The current study approaches by molecular docking and virtual screening to elucidate inhibitor with superior affinity against IDH2 and achieve a pharmacological profile. To obtain the best established drug Molegro Virtual Docker algorithm was executed. The compound AG-221 (Pub CID 71299339) having the high affinity score was subjected to similarity search to retrieve the drugs with similar properties. The virtual screened compound SCHEMBL16391748 (PubChem CID-117816179) shows high affinity for the protein. Comparative study and ADMET study for both the above compounds resulted in equivalent chemical properties. Virtual screened compound SCHEMBL16391748 (PubChem CID-117816179) shows the lowest re-rank score. These drugs are identified as high potential IDH2 inhibitors and can halt AML when validated through further In vitro screening.

LMO2 activation by deacetylation is indispensable for hematopoiesis and T-ALL leukemogenesis

Hematopoietic transcription factor LIM domain only 2 (LMO2), a member of the TAL1 transcriptional complex, plays an essential role during early hematopoiesis and is frequently activated in T-cell acute lymphoblastic leukemia (T-ALL) patients. Here, we demonstrate that LMO2 is activated by deacetylation on lysine 74 and 78 via the nicotinamide phosphoribosyltransferase (NAMPT)/sirtuin 2 (SIRT2) pathway. LMO2 deacetylation enables LMO2 to interact with LIM domain binding 1 and activate the TAL1 complex. NAMPT/SIRT2-mediated activation of LMO2 by deacetylation appears to be important for hematopoietic differentiation of induced pluripotent stem cells and blood formation in zebrafish embryos. In T-ALL, deacetylated LMO2 induces expression of TAL1 complex target genes HHEX and NKX3.1 as well as LMO2 autoregulation. Consistent with this, inhibition of NAMPT or SIRT2 suppressed the in vitro growth and in vivo engraftment of T-ALL cells via diminished LMO2 deacetylation. This new molecular mechanism may provide new therapeutic possibilities in T-ALL and may contribute to the development of new methods for in vitro generation of blood cells.

Down-regulation of miR-29c is a prognostic biomarker in acute myeloid leukemia and can reduce the sensitivity of leukemic cells to decitabine

Background

MicroRNA-29c (miR-29c) is abnormally expressed in several cancers and serves as an important predictor of tumor prognosis. Herein, we investigate the effects of abnormal miR-29c expression and analyze its clinical significance in acute myeloid leukemia (AML) patients. In addition, decitabine (DAC) has made great progress in the treatment of AML in recent years, but DAC resistance is still common phenomenon and the mechanism of resistance is still unclear. We further analyze the influences of miR-29c to leukemic cells treated with DAC.

Methods

Real-time quantitative PCR (RQ-PCR) was carried out to detect miR-29c transcript level in 102 de novo AML patients and 25 normal controls. miR-29c/shRNA-29c were respectively transfected into K562 cells and HEL cells. Cell viability after transfection was detected by cell counting Kit-8 assays. Flow cytometry was used to detect apoptosis.

Results

MiR-29c was significantly down-regulated in AML (P < 0.001). Low miR-29c expression was frequently observed in patients with poor karyotype and high risk (P = 0.006 and 0.013, respectively). Patients with low miR-29c expression had a markedly shorter overall survival (OS) than those with high miR-29c expression (P < 0.001). Multivariate analysis confirmed the independent prognostic value of low miR-29c expression in both the whole cohort as well as the cytogenetically normal AML (CN-AML) subset. Over-expression of miR-29c in K562 treated with DAC inhibited growth, while silencing of miR-29c in HEL promoted growth and inhibited apoptosis. MiR-29c overexpression decreased the half maximal inhibitory concentration (IC₅₀) of DAC in K562, while miR-29c silencing increased the IC₅₀ of DAC in HEL. The demethylation of the miR-29c promoter was associated with its up-regulated expression. Although miR-29c demethylation was also observed in DAC-resistant K562 (K562/DAC), miR-29c expression was down-regulated. MiR-29c transfection also promoted apoptosis and decreased the IC₅₀ of DAC in K562/DAC cells.

Conclusions

Our results suggest that miR-29c down-regulation may act as an independent prognostic biomarker in AML patients, and miR-29c over-expression can increase the sensitivity of both non-resistant and resistant of leukemic cells to DAC.

Electronic supplementary material

The online version of this article (10.1186/s12935-019-0894-y) contains supplementary material, which is available to authorized users.

High expression of microRNA-500 is associated with poor prognosis in patients with acute myeloid leukemia receiving allogeneic hematopoietic stem cell transplantation

MicroRNA-500 (miR-500) is a potential prognostic biomarker in a number of different types of cancer, such as prostate cancer and hepatocellular carcinoma. This study aimed to explore the clinical implications of miR-500 expression status in patients with acute myeloid leukemia (AML) that had received allogeneic hematopoietic stem cell transplantation (allo-HSCT). miR-500 expression status and clinical data were obtained from 74 patients with AML in the The Cancer Genome Atlas database receiving allo-HSCT. Patients with low expression level of miR-500 (miR-500_low) were significantly more likely to present with a French-American-British classification M2 subtype (P=0.003), and less likely to have the M5 subtype (P=0.040) compared with patients with high expression levels (miR-500_high). miR-500_low patients were associated with low-risk AML (P=0.003) and core-binding factor subunit b-myosin heavy chain 11 translocation mutation (P=0.021). There was a significant difference in nucleophosmin 1 (P=0.009), NRAS proto-oncogene GTPase/KRAS proto-oncogene GTPase (P=0.047) and PHD finger protein 6 (P=0.040) expression levels between the two groups. miR-500_high patients had a decreased overall survival (OS) time compared with the low expression group (P=0.035). Multivariate analysis revealed that miR-500 expression significantly affected OS time independent of other classical prognostic factors, such as age and common mutations. The analysis of survival curves further substantiated this result. The results obtained in the current study suggested that miR-500 may be a suitable prognostic marker for patients with AML receiving allo-HSCT.

Disruption of R867 and Y613 interaction plays key roles in JAK2 R867Q mutation caused acute leukemia

Janus tyrosine kinase 2 (JAK2) mediates downstream signaling of cytokine receptors in all hematological lineages, constitutively active somatic JAK2 mutations were important for the leukemogenesis of acute leukemia (AL). The JAK2 R867Q somatic mutation is detected in a subset of AL patients. However, roles of JAK2 R867Q mutation in the pathogenesis of AL remain unclear. In this study, homology modeling analysis showed that loss of interaction between R867 and Y613 disrupted the JAK2 JH1/JH2 domain's interactions was responsible for its activation. JAK2 R867Q and mutations (R867A and R867G) abolished this interaction caused JAK2 constitutive activation. While, mutations (R867K, Y613E, R867K/Y613E) repairing this interaction reduced JAK2 R867Q mutation's activity. Furthermore, our studies showed that abolished R867 and Y613 interaction disrupted JH1/JH2 domains' interactions and led to JAK2 constitutive activation. More importantly, mutations (R867Q, R867A and R867G) disrupted this interaction enhanced the activity of JAK2-STAT5 pathway and the proliferation of Ba/F3 and MV4-11 cells. Further study showed that JAK2 R867Q mutation promoted the expression of proliferation marker and inhibited the differentiation marker of Ba/F3 and MV4-11 cells. Thus our studies provide clues in understanding the pathogenesis of JAK2 R867Q mutation in AL.

Dual FLT3 inhibitors: Against the drug resistance of acute myeloid leukemia in recent decade

Acute myeloid leukemia (AML) is a malignant disease characterized by abnormal growth and differentiation of hematopoietic stem cells. Although the pathogenesis has not been fully elucidated, many specific gene mutations have been found in AML. Fms-like tyrosine kinase 3 (FLT3) is recognized as a drug target for the treatment of AML, and the activation mutations of FLT3 were found in about 30% of AML patients. Targeted inhibition of FLT3 receptor tyrosine kinase has shown promising results in the treatment of FLT3 mutation AML. Unfortunately, the therapeutic effects of FLT3 tyrosine kinase inhibitors used as AML monotherapy are usually accompanied by the high risk of resistance development within a few months after treatment. FLT3 dual inhibitors were generated with the co-inhibition of FLT3 and another target, such as CDK4, JAK2, MEK, Mer, Pim, etc., to solve the problems mentioned above. As a result, the therapeutic effect of the drug is significantly improved, while the toxic and side effects are reduced. Besides, the life quality of AML patients with FLT3 mutation has been effectively improved. In this paper, we reviewed the studies of dual FLT3 inhibitors that have been discovered in recent years for the treatment of AML.

Radotinib inhibits mitosis entry in acute myeloid leukemia cells via suppression of Aurora kinase A expression

Aurora kinases play critical roles in regulating several processes pivotal for mitosis. Radotinib, which is approved in South Korea as a second-line treatment for chronic myeloid leukemia, inhibits the tyrosine kinase BCR-ABL and platelet-derived growth factor receptor. However, the effects of radotinib on Aurora kinase expression in acute myeloid leukemia are not well studied. Interestingly, the cytotoxicity of acute myeloid leukemia cells was increased by radotinib treatment. Radotinib significantly decreased the expression of cyclin-dependent kinase 1 and cyclin B1, the key regulators of G2/M phase, and inhibited the expression of Aurora kinase A and Aurora kinase B in acute myeloid leukemia cells. In addition, radotinib decreased the expression and binding between p-Aurora kinase A and TPX2, which are required for spindle assembly. Furthermore, it reduced Aurora kinase A and polo-like kinase 1 phosphorylation and suppressed the expression of α-, β-, and γ-tubulin in acute myeloid leukemia cells. Furthermore, radotinib significantly suppressed the key regulators of G2/M phase including cyclin B1 and Aurora kinase A in a xenograft animal model. Therefore, our results suggest that radotinib can abrogate acute myeloid leukemia cell growth both in vitro and in vivo and may serve as a candidate agent or a chemosensitizer for treating acute myeloid leukemia.

Prognostic and Therapeutic Value of Day 14 Bone Marrow Aspiration in Adult Acute Myeloid Leukemia Patients

BACKGROUND

Early blast clearance to induction chemotherapy in acute myeloid leukemia (AML) is an important prognostic indicator of treatment outcome in addition to genetics and molecular genetics. We evaluated the prognostic value of bone marrow aspiration (BMA) at day 14 (D14) and impact on outcome to asses the timing of a second induction.

PATIENTS AND METHODS

This retrospective study included 303 adult AML patients managed at the National Cancer Institute, Cairo University, from the beginning of 2010 to the end of 2014.

RESULTS

Median age was 34 years (range, 18-67 years). Sixty-six percent had early blast clearance with < 5% blasts and 34% had ≥ 5% blasts at BMA D14; 38 patients died early during or shortly after induction. Initial blast load (bone marrow and peripheral blood) and initial platelet count were significantly higher in those with disease that did not respond to therapy compared to those whose disease did respond to therapy at D14 (P < .001, .035, and .006, respectively). The median disease-free survival for early blast clearance at D14 was 18.5 months, versus 18.7 months for those with late response to therapy (day 28), and was only 1.3 months for patients who received immediate second-line therapy on the basis of BMA D14 (P < .001). The median overall survival for early blast clearance was 13.6 months, versus 7.2 months for those with late response to therapy, and only 1.3 months for patients who received immediate second-line therapy on the basis of BMA D14 (P < .001).

CONCLUSION

BMA D14 has a significant prognostic impact on the therapeutic outcome of AML patients (complete remission, disease-free survival, and overall survival); however, a second induction in patients with BMA D14 blasts > 5% should be delayed until neutrophil recovery to minimize death in aplasia.

Targeting ADP-ribosylation by PARP inhibitors in acute myeloid leukaemia and related disorders

Acute myeloid leukaemia (AML) is a highly heterogeneous disease characterized by uncontrolled proliferation, block in myeloid differentiation and recurrent genetic abnormalities. In the search of new effective therapies, identification of synthetic lethal partners of AML genetic alterations might represent a suitable approach to tailor patient treatment. Genetic mutations directly affecting DNA repair genes are not commonly present in AML. Nevertheless, several studies indicate that AML cells show high levels of DNA lesions and genomic instability. Leukaemia-driving oncogenes (e.g., RUNX1-RUNXT1, PML-RARA, TCF3-HLF, IDH1/2, TET2) or treatment with targeted agents directed against aberrant kinases (e.g., JAK1/2 and FLT3 inhibitors) have been associated with reduced DNA repair gene expression/activity that would render leukaemia blasts selectively sensitive to synthetic lethality induced by poly(ADP-ribose) polymerase inhibitors (PARPi). Thus, specific oncogenic chimeric proteins or gene mutations, rare or typically distinctive of certain leukaemia subtypes, may allow tagging cancer cells for destruction by PARPi. In this review, we will discuss the rationale for using PARPi in AML subtypes characterized by a specific genetic background and summarize the preclinical and clinical evidence reported so far on their activity when used as single agents or in combination with classical cytotoxic chemotherapy or with agents targeting AML-associated mutated proteins.

Evaluating venetoclax and its potential in treatment-naïve acute myeloid leukemia

Venetoclax (ABT-199), a BH3-mimetic and selective BCL-2 inhibitor, was recently approved by the US Food and Drug Administration (FDA) for the treatment of acute myeloid leukemia (AML) in adult patients aged 75 years or older, or otherwise unable to tolerate intensive induction chemotherapy, in combination with either hypomethylating agents or low-dose cytarabine. In this review article, we discuss venetoclax’s mechanism of action, in relation to both the BCL-2 protein family in general and BH3-mimetic activity in particular. We then outline the pharmacological advances that preceded and facilitated its development, as well as providing an overview of key preclinical and clinical studies which lead to its use first in chronic lymphoid leukemia (CLL), then in small lymphocytic leukemia (SLL), and subsequently in AML. Finally, we seek to offer an overview of the challenges and opportunities encountered as venetoclax moves into more widespread use, including its use and activity against leukemia initiating cells and oxidative phosphorylation.

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.

MDM2 antagonists as a novel treatment option for acute myeloid leukemia: perspectives on the therapeutic potential of idasanutlin (RG7388)

Acute myeloid leukemia (AML) is a clonal heterogenous malignancy of the myeloid cells with a poor prognosis lending itself to novel treatment strategies. TP53 is a critical tumor suppressor and plays an essential role in leukemogenesis. Although TP53 is relatively unusual in de novo AML, inactivation of wild-type p53 (WT-p53) is a common event. Murine double minute 2 (MDM2) is a key negative regulator of p53 and its expression; inhibition of MDM2 is postulated to reactivate WT-p53 and its tumor suppressor functions. Nutlins were the first small molecule inhibitors that bind to MDM2 and target its interaction with p53. RG7388 (idasanutlin), a second-generation nutlin, was developed to improve upon the potency and toxicity profile of earlier nutlins. Preliminary data from early phase trials and ongoing studies suggest clinical response with RG7388 (idasanutlin) both in monotherapy and combination strategies in AML. We herein briefly discuss currently approved therapies in AML and review the clinical data for RG7388 (idasanutlin) and MDM2 inhibition as novel treatment strategies in AML. We further describe efficacy and toxicity profile data from completed and ongoing trials of RG7388 (idasanutlin) and other MDM2-p53 inhibitors in development. Many targeted therapies have been approved recently in AML, with a focus on the older and unfit population for intensive induction therapy and in relapsed/refractory disease. The "nutlins", including RG7388 (idasanutlin), merit continued investigation in such settings.

Ten-year outcome of patients with acute myeloid leukemia not treated with allogeneic transplantation in first complete remission

The probability that adult patients with de novo acute myeloid leukemia (AML) receiving intensive chemotherapy in the absence of allogeneic hematopoietic stem cell transplantation (Allo-HCT) in first complete remission (CR1) will be disease-free at 10 years after diagnosis, a long-term surrogate of cure, is unknown. To address this question, we examined 2551 AML patients (1607 aged <60 years, and 944 aged ≥60 years) enrolled in Cancer and Leukemia Group B treatment protocols and the cytogenetics companion protocol 8461 between 1983 and 2004. At 10 years, 267 (16.6%) of patients aged <60 years and 23 (2.4%) of those aged ≥60 years were alive and disease-free. This disease-free AML group consisted predominantly of patients with core-binding factor AML with t(8;21)(q22;q22) or inv(16)(p13q22)/t(16;16)(p13;q22) and those with a normal karyotype. Occurrences of AML beyond 10 years were infrequent and associated with cytogenetic findings different from those at diagnosis. These data provide evidence that the frequency of long-term cure of AML is low among younger and especially older patients in the absence of Allo-HCT in CR1. In older patients not appropriate for Allo-HCT, these data provide further justification for early use of alternative treatments outside of intensive chemotherapy.

Reduced protocadherin17 expression in leukemia stem cells: the clinical and biological effect in acute myeloid leukemia

Background

Leukemia stem cell (LSC)-enriched genes have been shown to be highly prognostic in acute myeloid leukemia (AML). However, the prognostic value of tumor suppressor genes (TSGs) that are repressed early in LSC remains largely unknown.

Methods

We compared the public available expression/methylation profiling data of LSCs with that of hematopoietic stem cells (HSCs), in order to identify potential tumor suppressor genes in LSC. The prognostic relevance of PCDH17 was analyzed on a cohort of 173 AML patients from The Cancer Genome Atlas (TCGA), and further validated in three independent cohorts (n = 339).

Results

We identified protocadherin17 (PCDH17) and demonstrated that it was significantly down-regulated and hypermethylated in LSCs compared with HSCs. Our analyses of primary AML patient samples also confirmed these deregulations. Clinically, low PCDH17 expression was associated with female sex (P = 0.01), higher WBC (P < 0.0001), higher percentages of blasts in bone marrow (BM) and peripheral blood (PB) (P = 0.04 and < 0.001, respectively), presence of FLT3-internal tandem duplications (P = 0.002), mutated NPM1 (P = 0.02), and wild-type TP53 (P = 0.005). Moreover, low PCDH17 expression predicted worse overall survival (OS) in four independent cohorts as well as in the molecularly defined subgroups of AML patients. In multivariable analyses, low PCDH17 expression retained independent prognostic value for OS. Biologically, PCDH17 expression-associated gene signatures were characterized by deregulations of EMT- and Wnt pathway-related genes.

Conclusions

PCDH17 gene was silenced by DNA methylation in AML. Low PCDH17 expression is associated with distinct clinical and biological features and improves risk stratification in patients with AML.

Electronic supplementary material

The online version of this article (10.1186/s12967-019-1851-1) contains supplementary material, which is available to authorized users.

Prognostic significance of PAK family kinases in acute myeloid leukemia

Acute myeloid leukemia (AML) is a clonal and heterogeneous disease characterized by a myriad of genetic defects. Genetic abnormalities are powerful prognostic factors. P21-activated kinases (PAKs) are a kind of serine/threonine protein kinases, which is regulator of plenty of oncogenic signaling pathways. The clinical and prognostic value of PAKs in AML is unclear. A total of 155 AML patients with PAK expression data from The Cancer Genome Atlas database were enrolled in this study. Eighty-four patients underwent chemotherapy only, 71 also underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT). In the chemotherapy-only group, high PAK3 and PAK7 expression were both bound up with poor EFS and OS (all P < 0.05). However, high PAK2 expressers had better EFS and OS (all P < 0.05). Multivariate analysis demonstrated that high PAK7 expression was an adverse independent prognostic factor in patients who received chemotherapy only. PAKs have no influence in EFS and OS in patients who underwent allo-HSCT. In conclusion, high PAK2 expression is a favorable prognostic factor, as to the high expression of PAK3 and PAK7, they are poor prognostic factors, and PAK7 has better prognostic value, but their prognostic effects can be offset by allo-HSCT.

Antileukemic activity and mechanism of action of the novel PI3K and histone deacetylase dual inhibitor CUDC-907 in acute myeloid leukemia

Induction therapy for patients with acute myeloid leukemia (AML) has remained largely unchanged for over 40 years, while overall survival rates remain unacceptably low, highlighting the need for new therapies. The PI3K/Akt pathway is constitutively active in the majority of patients with AML. Given that histone deacetylase inhibitors have been shown to synergize with PI3K inhibitors in preclinical AML models, we investigated the novel dual-acting PI3K and histone deacetylase inhibitor CUDC-907 in AML cells both in vitro and in vivo. We demonstrated that CUDC-907 induces apoptosis in AML cell lines and primary AML samples and shows in vivo efficacy in an AML cell line-derived xenograft mouse model. CUDC-907-induced apoptosis was partially dependent on Mcl-1, Bim, and c-Myc. CUDC-907 induced DNA damage in AML cells while sparing normal hematopoietic cells. Downregulation of CHK1, Wee1, and RRM1, and induction of DNA damage also contributed to CUDC-907-induced apoptosis of AML cells. In addition, CUDC-907 treatment decreased leukemia progenitor cells in primary AML samples ex vivo, while also sparing normal hematopoietic progenitor cells. These findings support the clinical development of CUDC-907 for the treatment of AML.

Clonal Hematopoiesis with Oncogenic Potential (CHOP): Separation from CHIP and Roads to AML

The development of leukemia is a step-wise process that is associated with molecular diversification and clonal selection of neoplastic stem cells. Depending on the number and combinations of lesions, one or more sub-clones expand/s after a variable latency period. Initial stages may develop early in life or later in adulthood and include premalignant (indolent) stages and the malignant phase, defined by an acute leukemia. We recently proposed a cancer model in which the earliest somatic lesions are often age-related early mutations detectable in apparently healthy individuals and where additional oncogenic mutations will lead to the development of an overt neoplasm that is usually a preleukemic condition such as a myelodysplastic syndrome. These neoplasms may or may not transform to overt acute leukemia over time. Thus, depending on the type and number of somatic mutations, clonal hematopoiesis (CH) can be divided into CH with indeterminate potential (CHIP) and CH with oncogenic potential (CHOP). Whereas CHIP mutations per se usually create the molecular background of a neoplastic process, CHOP mutations are disease-related or even disease-specific lesions that trigger differentiation and/or proliferation of neoplastic cells. Over time, the acquisition of additional oncogenic events converts preleukemic neoplasms into secondary acute myeloid leukemia (sAML). In the present article, recent developments in the field are discussed with a focus on CHOP mutations that lead to distinct myeloid neoplasms, their role in disease evolution, and the impact of additional lesions that can drive a preleukemic neoplasm into sAML.

FLT3 internal tandem duplication does not impact prognosis after haploidentical allogeneic hematopoietic stem cell transplantation in AML patients

Acute myelogenous leukemia (AML) patients with fetal liver tyrosine kinase 3 (FLT3) internal tandem duplications (ITDs) have poor prognoses if treated with chemotherapy only, primarily as they experience increased relapse rates. To determine whether this alteration also affects outcomes after haploidentical donor (HID) allogeneic hematopoietic stem cell transplantation (allo-HSCT), we compared 334 consecutive FLT3-ITD-positive vs -negative patients with AML (other than acute promyelocytic leukemia) who underwent HID-HSCT. FLT3-ITD was detected in 39 of 334 patients (11.7%). The 2-year relapse rates for FLT3-ITD-positive and -negative patients were 16% and 17%, respectively (P = 0.774). The 3-year disease-free survival (DFS) rates for FLT3-ITD-positive and -negative patients were 74% (95% confidence interval [CI]: 64-81) and 73% (95% CI: 70-81), respectively; P = 0.872); while the 3-year overall survival (OS) rates were 72% (95% CI: 67-81) and 77% (95% CI: 72-84), respectively (P = 0.862). FLT3-ITD mutation had no influence on non-relapse mortality (NRM 15% vs 14%, P = 0.463). Multivariate analyses showed that disease status at HSCT and white blood cell count at diagnosis were independent risk factors associated with relapse, DFS, and OS. In conclusion, FLT3 mutation status has no impact on outcomes after HID-HSCT in patients with AML. HID-HSCT is therefore a valid option for AML patients with FLT3-ITD mutation.

CDA as a predictive marker for life-threatening toxicities in patients with AML treated with cytarabine

Cytarabine (Ara-C) is the backbone of acute myeloid leukemia (AML) chemotherapy. Little is known about possible risk factors predictive for the frequent (ie, up to 16%) life-threatening or lethal toxicities caused by Ara-C. Ara-C is detoxified in the liver by a single enzyme, cytidine deaminase (CDA), coded by a gene known to be highly polymorphic. In this proof-of-concept study, we particularly investigated the role of the CDA poor metabolizer (PM) phenotype in Ara-C toxicities. CDA phenotyping (measurement of CDA residual activity in serum) and genotyping (search for the CDA*2 allelic variant) were performed in 58 adult patients with AML treated with the standard 7+3 (Ara-C + anthracyclines) protocol. Statistically significantly lower CDA activity was observed in patients experiencing severe/lethal toxicities as compared with patients who did not (1.5 ± 0.7 U/mg vs 3.95 ± 3.1 U/mg; Student t test P < .001). Subsequent receiver operating characteristic analysis identified a threshold in CDA activity (ie, 2 U/mg) associated with PM syndrome and increased risk of developing severe toxicities. Five percent of patients experienced lethal toxicities, all displaying CDA PM status (1.3 ± 0.5 U/mg). In terms of efficacy, a trend toward higher response rates and longer progression-free survival and overall survival were observed in patients with low CDA activity. Taken together, the results of this study strongly suggest that CDA is a predictive marker of life-threatening toxicities in patients with AML receiving induction therapy with standard Ara-C.

Early recovery of the platelet count after decitabine-based induction chemotherapy is a prognostic marker of superior response in elderly patients with newly diagnosed acute myeloid leukaemia

BACKGROUND

Definite prognostic clinical factors of benefit for decitabine-based induction chemotherapy in elderly patients newly diagnosed with acute myeloid leukaemia (AML) are not identified. This study was designed to explore the potential biomarker, especially regeneration of haematopoiesis, of treatment response and survival in elderly patients with newly diagnosed AML.

METHOD

We analysed the clinical data of 117 elderly AML patients who were treated with a decitabine dose of 15 mg/m² for 5 days, granulocyte colony-stimulating factor of 300 μg/d for priming, plus cytarabine 10 mg/m² q12h for 7 days and aclarubicin 10 mg/d for 4 days (D-CAG).

RESULTS

After initial induction chemotherapy, the overall response rate and complete remission (CR) were 71.8% and 58.1%, respectively. Patients responding to the D-CAG regimen achieved higher platelet counts on day 14 after initial treatment (p < 0.001). Median counts were 59.5 × 10⁹/L in the CR group, 37 × 10⁹/L in the partial remission group and 28 × 10⁹/L in the non-responsive group. We then classified patients into those who achieved platelet counts≥60 × 10⁹/L or 100 × 10⁹/L on day 14 after D-CAG vs. those who did not. Platelet counts≥60 × 10⁹/L or 100 × 10⁹/L on day 14 were significantly associated with superior CR, overall survival and disease-free survival (80.9% vs. 45.3% p < 0.001,16.5 vs. 9.1 months p = 0.009 and 16.3 vs. 7.4 months p = 0.024; 85.2% vs. 50% p = 0.001, 31 vs. 10.1 months p = 0.003 and 16.9 vs. 8.9 months p = 0.006). Multivariate analysis confirmed that poor cytogenetics (p = 0.010) and FLT3-ITD mutation (p = 0.007) were identified as independent factors of OS, but not platelet count (p = 0.091). However, platelet count≥100 × 10⁹/L on day 14 was an independent prognostic factor of CR and DFS.

CONCLUSION

Platelet count recovery on day 14 after D-CAG induction chemotherapy is associated with response.

TRIAL REGISTRATION

D-CAG regimen was registered on ChicTR with number 11001700 .

New drugs for acute myeloid leukemia inspired by genomics and when to use them

We are several years into the "postdiscovery" era in acute myeloid leukemia (AML) thanks to extensive work involving the sequencing of genomes and exomes of countless patients, which has led to routine comprehensive targeted sequencing in clinical care. The ability to unlock the molecular underpinnings of each patient's disease was supposed to usher in a new treatment era in which each patient was assigned, based on her mutational profile, a personalized cocktail of targeted therapies that would snuff the disease into submission with minimal toxicity. Whether we have fully realized the promise of personalized therapy in AML is unclear. Here, I review those new drugs that have been inspired by genomics, discuss others that might be possible and their potential roles, and consider whether the ability to target genomic mutations in a personalized manner constitutes the future of AML therapeutics or is representative of an era that has already passed.

miR‑1271‑5p inhibits cell proliferation and induces apoptosis in acute myeloid leukemia by targeting ZIC2

MicroRNAs (miRNAs) have been demonstrated to regulate the progression of numerous types of cancer, including acute myeloid leukemia (AML). Previous studies demonstrated that miR‑1271‑5p functions as a tumor suppressor; however, the roles of miR‑1271‑5p in AML remain unknown. In the present study, miR‑1271‑5p was significantly downregulated in AML tissues compared with normal tissues by reverse transcription‑quantitative polymerase chain reaction analysis. Furthermore, the expression levels of miR‑1271‑5p in patients with AML may function as a prognostic marker. In addition, overexpression of miR‑1271‑5p significantly suppressed the proliferation and induced apoptosis of AML cells by Cell Counting kit‑8 and fluorescence activated cell sorter assays; miR‑1271‑5p downregulation exhibited opposing effects. Additionally, transcription factor ZIC2 may be a direct target of miR‑1271‑5p in AML cells, which was demonstrated by a luciferase reporter assay and RNA pulldown assay. Overexpression of miR‑1271‑5p significantly reduced the mRNA and protein expression levels of ZIC2 in AML193 and OCI‑AML2 cells by reverse transcription‑quantitative polymerase chain reaction analysis and western blotting. Furthermore, an inverse correlation between miR‑1271‑5p and ZIC2 expression in AML samples was observed. In summary, ZIC2 was upregulated in AML tissues, and restoration of ZIC2 expression was able to promote the proliferation and reduce the apoptosis of AML cells transfected with miR‑1271‑5p mimics. The results of the present study demonstrated that miR‑1271‑5p inhibited the progression of AML by targeting ZIC2.

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.

The Progress of Next Generation Sequencing in the Assessment of Myeloid Malignancies

The introduction and advances on next-generation sequencing have led to novel ways to integrate simultaneous assessment of multiple target genes in routine laboratory analysis. Assessment of myeloid neoplasms with targeted next-generation sequencing panels shows evidence to improve diagnosis, assist therapeutic decisions, provide better information about prognosis, and better detection of minimal residual disease. Herein, we provide information for application and utilization of next-generation sequencing studies with a focus on the most important mutations in acute myeloid leukemia, myelodysplastic syndrome, myeloproliferative neoplasms, and other myelodysplastic / myeloproliferative neoplasms in order to integrate them into the daily clinical practice.

Efficacy and safety of lenalidomide for the treatment of acute myeloid leukemia: a systematic review and meta-analysis

Background

Lenalidomide is effective for the treatment of low-risk myelodysplastic syndromes with deletion 5q abnormalities. However, whether lenalidomide leads to a significant improvement in treatment response and overall survival (OS) in cases of acute myeloid leukemia (AML) remains controversial. A systematic review and a meta-analysis were performed to evaluate the efficacy and safety of lenalidomide in the treatment of AML.

Methods

Clinical studies were identified from the Cochrane Central Register of Controlled Trials, PubMed, Embase, and ClinicalTrials.gov. Efficacy outcomes included overall response rate (ORR), complete remission (CR), and OS. Safety was evaluated based on the incidence of grade 3 and 4 treatment-related adverse events (AEs).

Results

Eleven studies were included in our meta-analysis; collectively these studies featured 407 AML patients. Pooled estimates for overall ORR and CR were 31% (95% CI: 26%–36%) and 21% (95% CI: 16%–27%), respectively. Thrombocytopenia, anemia, neutropenia, and infection were the most common grade 3 and 4 AEs.

Conclusion

Lenalidomide may have some clinical activity in AML, but the population that would benefit from lenalidomide and incorporating lenalidomide into combination drug strategies need to be better defined.

DIXDC1 promotes the growth of acute myeloid leukemia cells by upregulating the Wnt/β-catenin signaling pathway

Accumulating evidence suggests that dysregulation of Dishevelled-Axin domain-containing 1 (DIXDC1) is involved in the progression and development of various cancers. However, little is known about the relevance of DIXDC1 in acute myeloid leukemia (AML). In this study, we aimed to investigate the expression status and potential biological function of DIXDC1 in AML. Our results showed that DIXDC1 expression was highly upregulated in AML cell lines and primary AML blasts compared with normal blasts. Knockdown of DIXDC1 by siRNA-mediated gene silencing significantly inhibited proliferation, induced cell cycle arrest, and promoted apoptosis of AML cells in vitro. By contrast, DIXDC1 overexpression promoted proliferation, accelerated cell cycle progression, and reduced apoptosis of AML cells. Moreover, we found that DIXDC1 knockdown decreased the expression of β-catenin and restricted the activation of Wnt signaling. In addition, DIXDC1 knockdown decreased the expression of Wnt/β-catenin target genes, including cyclin D1 and c-myc, while DIXDC1 overexpression had the opposite effect. Notably, β-catenin knockdown partially reversed the oncogenic effect of DIXDC1 in AML cells. Taken together, these results demonstrate that DIXDC1 promotes the growth of AML cells, possibly through upregulating the Wnt/β-catenin signaling pathway. Our study suggests that DIXDC1 may serve as a potential therapeutic target for the treatment of AML.

MicroRNA-143 targets ERK5 in granulopoiesis and predicts outcome of patients with acute myeloid leukemia

Hematopoiesis, the formation of blood cells from hematopoietic stem cells (HSC), is a highly regulated process. Since the discovery of microRNAs (miRNAs), several studies have shown their significant role in the regulation of the hematopoietic system. Impaired expression of miRNAs leads to disrupted cellular pathways and in particular causes loss of hematopoietic ability. Here, we report a previously unrecognized function of miR-143 in granulopoiesis. Hematopoietic cells undergoing granulocytic differentiation exhibited increased miR-143 expression. Overexpression or ablation of miR-143 expression resulted in accelerated granulocytic differentiation or block of differentiation, respectively. The absence of miR-143 in mice resulted in a reduced number of mature granulocytes in blood and bone marrow. Additionally, we observed an association of high miR-143 expression levels with a higher probability of survival in two different cohorts of patients with acute myeloid leukemia (AML). Overexpression of miR-143 in AML cells impaired cell growth, partially induced differentiation, and caused apoptosis. Argonaute2-RNA-Immunoprecipitation assay revealed ERK5, a member of the MAPK-family, as a target of miR-143 in myeloid cells. Further, we observed an inverse correlation of miR-143 and ERK5 in primary AML patient samples, and in CD34⁺ HSPCs undergoing granulocytic differentiation and we confirmed functional relevance of ERK5 in myeloid cells. In conclusion, our data describe miR-143 as a relevant factor in granulocyte differentiation, whose expression may be useful as a prognostic and therapeutic factor in AML therapy.

Identification and validation of SRY-box containing gene family member SOX30 methylation as a prognostic and predictive biomarker in myeloid malignancies

Background

Methylation-associated SOX family genes have been proved to be involved in multiple essential processes during carcinogenesis and act as potential biomarkers for cancer diagnosis, staging, prediction of prognosis, and monitoring of response to therapy. Herein, we revealed SOX30 methylation and its clinical implication in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS).

Results

In the discovery stage, we identified that SOX30 methylation, a frequent event in AML, was negatively associated with SOX30 expression and correlated with overall survival (OS) and leukemia-free survival (LFS) in cytogenetically normal AML among SOX family members from The Cancer Genome Atlas (TCGA) datasets. In the validation stage, we verified that SOX30 methylation level was significantly higher in AML even in MDS-derived AML compared to controls, whereas SOX30 hypermethylation was not a frequent event in MDS. SOX30 methylation was inversely correlated with SOX30 expression in AML patients. Survival analysis showed that SOX30 hypermethylation was negatively associated with complete remission (CR), OS, and LFS in AML, where it only affected LFS in MDS. Notably, among MDS/AML paired patients, SOX30 methylation level was significantly increased in AML stage than in MDS stage. In addition, SOX30 methylation was found to be significantly decreased in AML achieved CR when compared to diagnosis time and markedly increased in relapsed AML when compared to the CR population.

Conclusions

Our findings revealed that SOX30 methylation was associated with disease progression in MDS and acted as an independent prognostic and predictive biomarker in AML.

Electronic supplementary material

The online version of this article (10.1186/s13148-018-0523-y) contains supplementary material, which is available to authorized users.

Dysregulation of miR-200s clusters as potential prognostic biomarkers in acute myeloid leukemia

Background

Increasing studies showed that miR-200 family (miR-200s) clusters are aberrantly expressed in multiple human cancers, and miR-200s clusters function as tumor suppressor genes by affecting cell proliferation, self-renewal, differentiation, division and apoptosis. Herein, we aimed to investigate the expression and clinical implication of miR-200s clusters in acute myeloid leukemia (AML).

Methods

RT-qPCR was performed to detect expression of miR-200s clusters in 19 healthy donors, 98 newly diagnosed AML patients, and 35 AML patients achieved complete remission (CR).

Results

Expression of miR-200a/200b/429 cluster but not miR-200c/141 cluster was decreased in newly diagnosed AML patients as compared to healthy donors and AML patients achieved CR. Although no significant differences were observed between miR-200s clusters and most of the features, low expression of miR-200s clusters seems to be associated with higher white blood cells especially for miR-200a/200b. Of the five members of miR-200s clusters, low expression of miR-200b/429/200c was found to be associated with lower CR rate. Logistic regression analysis further revealed that low expression of miR-429 acted as an independent risk factor for CR in AML. Based on Kaplan–Meier analysis, low expression of miR-200b/429/200c was associated with shorter OS, whereas miR-200a/141 had a trend. Moreover, multivariate analysis of Cox regression models confirmed the independently prognostic value of miR-200b expression for OS in AML.

Conclusions

Expression of miR-200a/200b/429 cluster was frequently down-regulated in AML, and low expression of miR-429 as an independent risk factor for CR, whereas low expression of miR-200b as an independent prognostic biomarker for OS.

Electronic supplementary material

The online version of this article (10.1186/s12967-018-1494-7) contains supplementary material, which is available to authorized users.

CTCF boundary remodels chromatin domain and drives aberrant HOX gene transcription in acute myeloid leukemia

HOX gene dysregulation is a common feature of acute myeloid leukemia (AML). The molecular mechanisms underlying aberrant HOX gene expression and associated AML pathogenesis remain unclear. The nuclear protein CCCTC-binding factor (CTCF), when bound to insulator sequences, constrains temporal HOX gene-expression patterns within confined chromatin domains for normal development. Here, we used targeted pooled CRISPR-Cas9-knockout library screening to interrogate the function of CTCF boundaries in the HOX gene loci. We discovered that the CTCF binding site located between HOXA7 and HOXA9 genes (CBS7/9) is critical for establishing and maintaining aberrant HOXA9-HOXA13 gene expression in AML. Disruption of the CBS7/9 boundary resulted in spreading of repressive H3K27me3 into the posterior active HOXA chromatin domain that subsequently impaired enhancer/promoter chromatin accessibility and disrupted ectopic long-range interactions among the posterior HOXA genes. Consistent with the role of the CBS7/9 boundary in HOXA locus chromatin organization, attenuation of the CBS7/9 boundary function reduced posterior HOXA gene expression and altered myeloid-specific transcriptome profiles important for pathogenesis of myeloid malignancies. Furthermore, heterozygous deletion of the CBS7/9 chromatin boundary in the HOXA locus reduced human leukemic blast burden and enhanced survival of transplanted AML cell xenograft and patient-derived xenograft mouse models. Thus, the CTCF boundary constrains the normal gene-expression program, as well as plays a role in maintaining the oncogenic transcription program for leukemic transformation. The CTCF boundaries may serve as novel therapeutic targets for the treatment of myeloid malignancies.

Novel Therapies for Acute Myeloid Leukemia: Are We Finally Breaking the Deadlock?

Acute myeloid leukemia (AML) is one of the best studied malignancies, and significant progress has been made in understanding the clinical implications of its disease biology. Unfortunately, drug development has not kept pace, as the '7+3' induction regimen remains the standard of care for patients fit for intensive therapy 40 years after its first use. Temporal improvements in overall survival were mostly confined to younger patients and driven by improvements in supportive care and use of hematopoietic stem cell transplantation. Multiple forms of novel therapy are currently in clinical trials and are attempting to bring bench discoveries to the bedside to benefit patients. These novel therapies include improved chemotherapeutic agents, targeted molecular inhibitors, cell cycle regulators, pro-apoptotic agents, epigenetic modifiers, and metabolic therapies. Immunotherapies in the form of vaccines; naked, conjugated and bispecific monoclonal antibodies; cell-based therapy; and immune checkpoint inhibitors are also being evaluated in an effort to replicate the success seen in other malignancies. Herein, we review the scientific basis of these novel therapeutic approaches, summarize the currently available evidence, and look into the future of AML therapy by highlighting key clinical studies and the challenges the field continues to face.

NKp30 expression is a prognostic immune biomarker for stratification of patients with intermediate-risk acute myeloid leukemia

Cytogenetics and European Leukemia Net (ELN) genetic classification predict patients at increased risk of relapse in acute myeloid leukemia (AML) except in the intermediate risk group for which further prognostic determinants are required. We have previously shown that Natural Killer (NK) cell defects in AML are predictors of poor overall survival (OS). This study aimins at validating NKp30, a receptor that mediates NK activation, as a prognostic biomarker for AML patients with intermediate prognosis.

NKp30 expression was prospectively assessed at diagnosis on NK cells from peripheral blood by flow cytometry (N = 201 patients). Clinical outcome was evaluated with regard to NKp30 status.

In patients with intermediate cytogenetic (N = 162), NKp30^high phenotype at diagnosis was predictive of better OS (HR = 0.26; 95%CI = [0.14-0.50]; P < 0.0001) and relapse-free survival (RFS) (HR = 0.21; 95%CI = [0.08-0.52]; P = 0.0007). In patients with intermediate ELN (N = 116), NKp30^high phenotype at diagnosis was predictive of better OS (HR = 0.33; 95%CI = [0.16–0.67]; P = 0.0019) and RFS (HR = 0.24; 95%CI = [0.08-0.67]; P = 0.0058). In multivariate analysis, high NKp30 expression independently predicted improved OS (HR = 0.56, P = 0.046) and RFS (HR = 0.37, P = 0.048). Consistently, cumulative incidence of relapse (CIR) was lower in patients with high NKp30 expression (HR = 0.37, P = 0.026).

In conclusion, we propose NKp30 status as a simple and early prognostic biomarker that identifies intermediate-risk patients with poor prognosis who otherwise may not be identified with existing risk stratification systems.

Diagnostic, Prognostic, and Predictive Utility of Recurrent Somatic Mutations in Myeloid Neoplasms

The classification and risk stratification of myeloid neoplasms, including acute myeloid leukemia, myelodysplastic syndromes, myelodysplastic syndromes/myeloproliferative neoplasms, and myeloproliferative neoplasms, have increasingly been guided by molecular genetic abnormalities. Gene expression analysis and next-generation sequencing have led to the ever increasing discovery of somatic gene mutations in myeloid neoplasms. Mutations have been identified in genes involved in epigenetic modification, RNA splicing, transcription factors, DNA repair, and the cohesin complex. These new somatic/acquired gene mutations have refined the classification of myeloid neoplasms and have been incorporated into the 2016 update of the World Health Organization (WHO) classification and the National Comprehensive Cancer Network guidelines. They have also been helpful in the development of new targeted therapeutic agents. In the present review, we describe the clinical utility of recently identified, clinically important gene mutations in myeloid neoplasms, including those incorporated in the 2016 update of the WHO classification.

Expression levels of long non-coding RNAs are prognostic for AML outcome

Background

Long non-coding RNA (lncRNA) expression has been implicated in a range of molecular mechanisms that are central in cancer. However, lncRNA expression has not yet been comprehensively characterized in acute myeloid leukemia (AML). Here, we assess to what extent lncRNA expression is prognostic of AML patient overall survival (OS) and determine if there are indications of lncRNA-based molecular subtypes of AML.

Methods

We performed RNA sequencing of 274 intensively treated AML patients in a Swedish cohort and quantified lncRNA expression. Univariate and multivariate time-to-event analysis was applied to determine association between individual lncRNAs with OS. Unsupervised statistical learning was applied to ascertain if lncRNA-based molecular subtypes exist and are prognostic.

Results

Thirty-three individual lncRNAs were found to be associated with OS (adjusted p value < 0.05). We established four distinct molecular subtypes based on lncRNA expression using a consensus clustering approach. LncRNA-based subtypes were found to stratify patients into groups with prognostic information (p value < 0.05). Subsequently, lncRNA expression-based subtypes were validated in an independent patient cohort (TCGA-AML). LncRNA subtypes could not be directly explained by any of the recurrent cytogenetic or mutational aberrations, although associations with some of the established genetic and clinical factors were found, including mutations in NPM1, TP53, and FLT3.

Conclusion

LncRNA expression-based four subtypes, discovered in this study, are reproducible and can effectively stratify AML patients. LncRNA expression profiling can provide valuable information for improved risk stratification of AML patients.

Electronic supplementary material

The online version of this article (10.1186/s13045-018-0596-2) contains supplementary material, which is available to authorized users.

Low Autophagy (ATG) Gene Expression Is Associated with an Immature AML Blast Cell Phenotype and Can Be Restored during AML Differentiation Therapy

Autophagy is an intracellular degradation system that ensures a dynamic recycling of a variety of building blocks required for self-renewal, homeostasis, and cell survival under stress. We used primary acute myeloid leukemia (AML) samples and human AML cell lines to investigate the regulatory mechanisms of autophagy and its role in AML differentiation. We found a significantly lower expression of key autophagy- (ATG-) related genes in primary AML as compared to healthy granulocytes, an increased autophagic activity during all-trans retinoic acid- (ATRA-) induced neutrophil differentiation, and an impaired AML differentiation upon inhibition of ATG3, ATG4D, and ATG5. Supporting the notion of noncanonical autophagy, we found that ATRA-induced autophagy was Beclin1-independent compared to starvation- or arsenic trioxide- (ATO-) induced autophagy. Furthermore, we identified PU.1 as positive transcriptional regulator of ATG3, ATG4D, and ATG5. Low PU.1 expression in AML may account for low ATG gene expression in this disease. Low expression of the autophagy initiator ULK1 in AML can partially be attributed to high expression of the ULK1-targeting microRNA-106a. Our data clearly suggest that granulocytic AML differentiation relies on noncanonical autophagy pathways and that restoring autophagic activity might be beneficial in differentiation therapies.

Prognostic Value of RUNX1 Mutations in AML: A Meta-Analysis

The RUNX1 (AML1) gene is a relatively infrequent mutational target in cases of acute myeloid leukemia (AML). Previous work indicated that RUNX1 mutations can have pathological and prognostic implications. To evaluate prognostic value, we conducted a meta-analysis of 4 previous published works with data for survival according to RUNX1 mutation status. Pooled hazard ratios for overall survival and disease-free survival were 1.55 (95% confidence interval (CI) = 1.11–2.15; p-value = 0.01) and 1.76 (95% CI = 1.24–2.52; p-value = 0.002), respectively, for cases positive for RUNX1 mutations. This evidence supports clinical implications of RUNX1 mutations in the development and progression of AML cases and points to the possibility of a distinct category within the newer WHO classification. Though it must be kept in mind that the present work was based on data extracted from observational studies, the findings suggest that the RUNX1 status can contribute to risk-stratification and decision-making in management of AML.

Mutation patterns identify adult patients with de novo acute myeloid leukemia aged 60 years or older who respond favorably to standard chemotherapy: an analysis of Alliance studies

Thus far, only 5-15% of AML patients aged ≥60 years are cured with chemotherapy. Identification of patients who are less (more) likely to respond to standard chemotherapy might enable early risk stratification toward alternative treatment regimens. We used a next-generation sequencing panel of 80 cancer- and/or leukemia-associated genes to profile molecularly 423 older patients with de novo AML. Using variables identified in multivariable models and co-occurring mutations in NPM1-mutated AML, we classified the patients into good-, intermediate-, and poor-risk groups for complete remission (CR) attainment, disease-free (DFS), and overall survival (OS). Whereas 81% of good-risk patients (comprising NPM1-mutated patients harboring mutations in chromatin remodeling, cohesin complex, methylation-related, spliceosome, and/or RAS pathway genes, FLT3-TKD, and/or patients without FLT3-ITD) achieved a CR, only 32% of poor-risk patients (with U2AF1, WT1 mutations and/or complex karyotype) did. Intermediate-risk patients had a 50% CR rate. Similarly, using NPM1 co-mutation patterns and SF1 mutation status, we identified patients with favorable DFS and OS 3-year rates of 46% and 45%, respectively. Patients with adverse genetic features had DFS and OS rates of only 2% and 4%. We show that application of our proposed criteria may refine the 2017 European LeukemiaNet classification for older patients treated with chemotherapy.