EVI1 overexpression is a poor prognostic factor in pediatric patients with mixed lineage leukemia-AF9 rearranged acute myeloid leukemia

Co-targeting BCL-XL and BCL-2 by PROTAC 753B eliminates leukemia cells and enhances efficacy of chemotherapy by targeting senescent cells

BCL-XL and BCL-2 are key anti-apoptotic proteins and validated cancer targets. 753B is a novel BCL-XL/BCL-2 proteolysis targeting chimera (PROTAC) that targets both BCL-XL and BCL-2 to the von Hippel-Lindau (VHL) E3 ligase, leading to BCLX L/BCL-2 ubiquitination and degradation selectively in cells expressing VHL. Because platelets lack VHL expression, 753B spares on-target platelet toxicity caused by the first-generation dual BCL-XL/BCL-2 inhibitor navitoclax (ABT-263). Here, we report pre-clinical single-agent activity of 753B against different leukemia subsets. 753B effectively reduced cell viability and induced dose-dependent degradation of BCL-XL and BCL-2 in a subset of hematopoietic cell lines, acute myeloid leukemia (AML) primary samples, and in vivo patient-derived xenograft AML models. We further demonstrated the senolytic activity of 753B, which enhanced the efficacy of chemotherapy by targeting chemotherapy-induced cellular senescence. These results provide a pre-clinical rationale for the utility of 753B in AML therapy, and suggest that 753B could produce an added therapeutic benefit by overcoming cellular senescence-induced chemoresistance when combined with chemotherapy.

The adverse impact of ecotropic viral integration site-1 (EVI1) overexpression on the prognosis of acute myeloid leukemia with KMT2A gene rearrangement in different risk stratification subtypes

INTRODUCTION

AML patients with KMT2A-MLLT3 and other 11q23 abnormalities belong to the intermediate and high-risk level groups, respectively. Whether the poor prognostic value of Ecotropic Viral Integration site-1 (EVI1) overexpression suits either the subtypes of KMT2A-MLLT3 or Non-KMT2A-MLLT3 AML patients (intermediate and high risk group) needs to be further investigated.

METHODS

We retrospectively analyzed the clinical characteristics of 166 KMT2A-r and KMT2A-PTD AML patients.

RESULTS

For the Non-KMT2A-MLLT3 group, patients in the EVI1-high subgroup had shorter OS and DFS and higher CIR than those in the EVI1-low subgroup (p = .027, p = .018, and p = .020, respectively). Additionally, both KMT2A-MLLT3 and Non-KMT2A-MLLT3 patients who received chemotherapy alone had poorer prognosis than patients who also received allogeneic hematopoietic stem cell transplant (allo-HSCT) regardless of their EVI1 expression level (all p < .001). For transplanted patients with KMT2A-MLLT3 or Non-KMT2A-MLLT3 rearrangement, the EVI1-high subgroup had worse prognosis than the EVI1-low subgroup (all p < .05). The 2-year CIR of the KMT2A-MLLT3 and Non-KMT2A-MLLT3 groups with high EVI1 expression was high (52% and 49.6%, respectively). However, for patients with low EVI1 expression, the 2-year CIR of transplanted patients with KMT2A-MLLT3 and Non-KMT2A-MLLT3 was relatively low.

CONCLUSIONS

Our study showed that for the Non-KMT2A-MLLT3 group, the EVI1-high group had shorter OS and DFS than the EVI1-low group. High EVI1 expression showed an adverse effect in AML with KMT2A rearrangement in different risk stratification subtypes. For the EVI1-high patients with non-KMT2A-MLLT3 rearrangement, other novel regimens towards relapse should be taken into consideration.

Clinical significance of EVI-1 gene expression and aberrations in patient with de-novo acute myeloid and acute lymphoid leukemia

BACKGROUND

Acute leukemia is a common health problem in adults and children, however its exact molecular etiology is still unclear.

METHODS

The expression of EVI-1 was assessed in the bone marrow of 178 de-novo acute leukemia patients (101 AML, 71 ALL and 6 MPAL), compared to 40 control subjects. EVI-1 gene aberrations were also assessed in 69 AML patients using Fluorescence in situ hybridization (FISH) technique.

RESULTS

The expression of EVI-1 was significantly lower in ALL patients compared to control [0.177 (0.002-15.189) vs 0.953 (0.179-1.68); respectively, P = 0.009]. There was no significant difference between AML patients and control group [0.150 (0.0-641) vs 0.953 (0.179-1.68); respectively, P = 0.082]. The sensitivity, specificity, AUC of EVI-1 in ALL were (80.3 %, 60 % and 0.778; respectively, P = 0.009), and (67.3 %, 60 %, 0.667; respectively P = 0.082) in AML patients. One patient showed EVI-1 gene rearrangement in a complex karyotype and four patients showed EVI-1 amplification in hyperdiploid karyotypes. All patients with BCR-ABL fusion were EVI-1 over-expressers (P = 0.010). AML patients with EVI-1 low expression were positively associated with t(8;21)(q22;q22)RUNX1:RUNX1T1 fusion, favorable recurrent translocation, and low genetic risk (P = 0.037, P = 0.023, and P = 0.013; respectively). There was a significant association between low EVI-1 expression and prolonged overall survival (OS) in AML patients, while there was no significant association with the disease-free survival (DFS) (P = 0.048 and P = 0.419). There was no significant impact of EVI-1 expression on OS and DFS rates in ALL patients.

CONCLUSION

EVI-1 expression could be a helpful diagnostic, prognostic, and predictive biomarker for acute leukemia especially in AML.

Comprehensive molecular understanding of pediatric acute myeloid leukemia

Pediatric acute myeloid leukemia (AML) is a heterogeneous disease with various genetic abnormalities. Recent advances in genetic analysis have enabled the identification of causative genes in > 90% of pediatric AML cases. Fusion genes such as RUNX1::RUNX1T1, CBFB::MYH11, and KMT2A::MLLT3 are frequently detected in > 70% of pediatric AML cases, whereas FLT3-internal tandem duplication, CEBPA-bZip, and NPM1 mutations are detected in approximately 5-15% of cases, respectively. Conversely, mutations in DNMT3A, TET2, and IDH, which are common in adults, are extremely rare in pediatric AML. The genetic characteristics of pediatric AML are slightly different from those of adult AML. For accurate risk stratification and treatment intensity, genome analysis should be performed in a simple, fast, and inexpensive manner and the results should be returned to patients in real time. As with acute lymphoblastic leukemia, the presence or absence of minimal residual disease is an important factor in determining the success of treatment against AML, and it is important to predict prognosis and formulate treatment strategies considering the genetic abnormalities. For the development and clinical application of new molecularly targeted therapies based on identified genetic abnormalities, it is necessary to explore when and in which combinations drugs will be most effective.

MECOM gene overexpression in pediatric patients with acute myeloid leukemia

BACKGROUND

Acute myeloid leukemia (AML) is characterized by blocked or aberrant differentiation of hematopoietic stem cells. The MECOM gene overexpression in hematopoietic progenitors induces myeloid differentiation block, resulting in increased self-renewal and survival of these transformed progenitors. However, its exact role in AML remains unclear. We aimed to estimate the prevalence of MECOM overexpression among pediatric AML patients, and assess its impact on clinical outcome.

PATIENTS AND METHODS

Real-time quantitative polymerase chain reaction and Livak method (2^ΔΔCt) were used to determine relative MECOM expression level among 243 pediatric patients with AML. MECOM overexpression was considered if the cumulative relative expression was above 1 (2^-ΔΔCt) and was designated as MECOM^pos.

RESULTS

Of 243 AML patients tested 57(23.5%) demonstrated MECOM^pos. Patients with MECOM^pos had significantly lower median age. The frequency of MECOM^pos was significantly higher among AML patients with 11q23 abnormalities, complex karyotypes and among high- and intermediate-risk groups compared to low-risk group (p = .014). MECOM^pos patients had significantly lower overall survival (OS) (38.7 vs. 78.9%, p < .001), event-free survival (EFS) (37.3% vs. 68.4%, p < .001), and had higher cumulative incidence of relapse (49.5% vs. 23.5%, p = .002) at 36 months compared to MECOM^neg patients. Multivariate analysis revealed that MECOM^pos was an adverse prognostic factor for OS (hazards ratio (HR) = 2.11, 95% confidence interval (CI) 1.24-3.60, p = .006) and EFS (HR= 1.71, 95% CI 1.07-2.75, p = .025). The logistic regression model showed that MECOM^pos was an independent prognostic factor regardless of minimal residual disease status post first induction therapy in the intermediate-risk group (odds ratio 2.89; 95% CI 1.19-6.57, p = .018).

CONCLUSION

The aberrant MECOM gene expression is an adverse prognostic factor, especially in patients without previously known cytogenetic risk factors. Our results suggest the potential benefit from pretreatment screening for MECOM gene overexpression in newly diagnosed AML patients for better risk stratification and treatment adjustment.

Genome-wide DNA Methylation Analysis in Pediatric Acute Myeloid Leukemia

FLT3-ITD and high PRDM16 expression induced methylation changes at STAT5 and AP-1 binding sites in pediatric AML.

Hypomethylated regions in PRDM16-highly expressed AMLs were correlated with enhanced chromatin accessibilities at multiple genomic regions.

We investigated genome-wide DNA methylation patterns in 64 pediatric patients with acute myeloid leukemia (AML). Based on unsupervised clustering with the 567 most variably methylated cytosine guanine dinucleotide (CpG) sites, patients were categorized into 4 clusters associated with genetic alterations. Clusters 1 and 3 were characterized by the presence of known favorable prognostic factors, such as RUNX1-RUNX1T1 fusion and KMT2A rearrangement with low MECOM expression, and biallelic CEBPA mutations (all 8 patients), respectively. Clusters 2 and 4 comprised patients exhibiting molecular features associated with adverse outcomes, namely internal tandem duplication of FLT3 (FLT3-ITD), partial tandem duplication of KMT2A, and high PRDM16 expression. Depending on the methylation values of the 1243 CpG sites that were significantly different between FLT3-ITD⁺ and FLT3-ITD⁻ AML, patients were categorized into 3 clusters: A, B, and C. The STAT5-binding motif was most frequently found close to the 1243 CpG sites. All 8 patients with FLT3-ITD in cluster A harbored high PRDM16 expression and experienced adverse events, whereas only 1 of 7 patients with FLT3-ITD in the other clusters experienced adverse events. PRDM16 expression levels were also related to DNA methylation patterns, which were drastically changed at the cutoff value of PRDM16/ABL1 = 0.10. The assay for transposase-accessible chromatin sequencing of AMLs supported enhanced chromatin accessibility around genomic regions, such as HOXB cluster genes, SCHIP1, and PRDM16, which were associated with DNA methylation changes in AMLs with FLT3-ITD and high PRDM16 expression. Our results suggest that DNA methylation levels at specific CpG sites are useful to support genetic alterations and gene expression patterns of patients with pediatric AML.

EVI1 promotes metastasis by downregulating TIMP2 in metastatic colon and breast cancer cells

Ecotropic viral integration site-1 (EVI1) is an oncogenic zinc finger transcription factor whose expression is frequently upregulated in a variety of cancers, including both myeloid malignancies and solid tumors. Previously, our group has shown that EVI1 knockdown minimizes the metastatic potential of colon cancer cells compared to that of control cells. In this study, to identify the potential targets that regulate cancer metastasis, control and EVI1 knockdown colon cancer cells were subjected to microarray. Differential gene expression analysis revealed significant downregulation of tissue inhibitor of matrix metalloproteinase-2 (TIMP2) in EVI1 expressing cells. EVI1 knockdown increased TIMP2 protein expression levels and reduced wound healing and migration capacity in metastatic cells. Mechanistically, the TIMP2 promoter harbors potential binding sites for EVI1; EVI1 binds to TIMP2 promoter and represses its expression, as observed using ChIP and luciferase assay, respectively. TIMP2 is an important metastasis suppressor gene; however, its function is suppressed in many cancers through hypermethylation. Thus, demethylation could prove to be a potential alternative to reactivate TIMP2 functional activity. Immunoprecipitation analysis showed that DNA-methyltransferase 1 (DNMT1), which plays a vital role in maintaining the genome methylation pattern during DNA replication and repair, interacts with EVI1 to promote TIMP2 silencing. Treating cancer cells in vitro with a known demethylation agent, 5-aza-2'-deoxycytidine (Aza-D), restored the optimal TIMP2 expression without altering EVI1 binding efficiency and reduced relative wound healing potential of cancer cells. Animal studies showed that Aza-D treated cells injected through the intravenous route exhibited reduced liver and skin metastasis when compared to non-treated cells. Furthermore, Aza-D treatment in mice delayed the metastasis progression compared to the vehicle treated group. Thus, the present study provides an insight into the therapeutic applications of demethylating agents to reduce cancer metastasis in models with EVI1 overexpressing tumors.

High EVI1 Expression Predicts Adverse Outcomes in Children With De Novo Acute Myeloid Leukemia

Background

A high ecotropic viral integration site 1 (EVI1) expression (EVI1^high) is an independent prognostic factor in adult acute myeloid leukemia (AML). However, little is known of the prognostic value of EVI1^high in pediatric AML. This study aimed to examine the biological and prognostic significance of EVI1^high in uniformly treated pediatric patients with AML from a large cohort of seven centers in China.

Methods

A diagnostic assay was developed to determine the relative EVI1 expression using a single real-time quantitative polymerase chain reaction in 421 newly diagnosed pediatric AML patients younger than 14 years from seven centers in southern China. All patients were treated with a uniform protocol, but only 383 patients were evaluated for their treatment response. The survival data were included in the subsequent analysis (n = 35 for EVI1^high, n = 348 for EVI1^low).

Results

EVI1^high was found in 9.0% of all 421 pediatric patients with de novo AML. EVI1^high was predominantly found in acute megakaryoblastic leukemia (FAB M7), MLL rearrangements, and unfavorable cytogenetic aberrance, whereas it was mutually exclusive with t (8; 21), inv (16)/t (16; 16), CEBPA, NPM1, or C-KIT mutations. In the univariate Cox regression analysis, EVI1^high had a significantly adverse 5-year event-free survival (EFS) and overall survival (OS) [hazard ratio (HR) = 1.821 and 2.401, p = 0.036 and 0.005, respectively]. In the multivariate Cox regression analysis, EVI1^high was an independent prognostic factor for the OS (HR = 2.447, p = 0.015) but not EFS (HR = 1.556, p = 0.174). Furthermore, EVI1^high was an independent adverse predictor of the OS and EFS of patients with MLL rearrangements (univariate analysis: HR = 9.921 and 7.253, both p < 0.001; multivariate analysis: HR = 7.186 and 7.315, p = 0.005 and 0.001, respectively). Hematopoietic stem cell transplantation (HSCT) in first complete remission (CR1) provided EVI1^high patients with a tendential survival benefit when compared with chemotherapy as a consolidation (5-year EFS: 68.4% vs. 50.8%, p = 0.26; 5-year OS: 65.9% vs. 54.8%, p = 0.45).

Conclusion

It could be concluded that EVI1^high can be detected in approximately 10% of pediatric AML cases. It is predominantly present in unfavorable cytogenetic subtypes and predicts adverse outcomes. Whether pediatric patients with EVI1^high AML can benefit from HSCT in CR1 needs to be researched further.

The transcriptome-wide landscape of molecular subtype-specific mRNA expression profiles in acute myeloid leukemia

Molecular classification of acute myeloid leukemia (AML) aids prognostic stratification and clinical management. Our aim in this study is to identify transcriptome-wide mRNAs that are specific to each of the molecular subtypes of AML. We analyzed RNA-sequencing data of 955 AML samples from three cohorts, including the BeatAML project, the Cancer Genome Atlas, and a cohort of Swedish patients to provide a comprehensive transcriptome-wide view of subtype-specific mRNA expression. We identified 729 subtype-specific mRNAs, discovered in the BeatAML project and validated in the other two cohorts. Using unique proteomics data, we also validated the presence of subtype-specific mRNAs at the protein level, yielding a rich collection of potential protein-based biomarkers for the AML community. To enable the exploration of subtype-specific mRNA expression by the broader scientific community, we provide an interactive resource to the public.

Fusion partner-specific mutation profiles and KRAS mutations as adverse prognostic factors in MLL-rearranged AML

Mixed-lineage leukemia (MLL) gene rearrangements are among the most frequent chromosomal abnormalities in acute myeloid leukemia (AML). MLL fusion patterns are associated with the patient's prognosis; however, their relationship with driver mutations is unclear. We conducted sequence analyses of 338 genes in pediatric patients with MLL-rearranged (MLL-r) AML (n = 56; JPLSG AML-05 study) alongside data from the TARGET study's pediatric cohorts with MLL-r AML (n = 104), non-MLL-r AML (n = 581), and adult MLL-r AML (n = 81). KRAS mutations were most frequent in pediatric patients with high-risk MLL fusions (MLL-MLLLT10, MLL-MLLT4, and MLL-MLLT1). Pediatric patients with MLL-r AML (n = 160) and a KRAS mutation (KRAS-MT) had a significantly worse prognosis than those without a KRAS mutation (KRAS-WT) (5-year event-free survival [EFS]: 51.8% vs 18.3%, P < .0001; 5-year overall survival [OS]: 67.3% vs 44.3%, P = .003). The adverse prognostic impact of KRAS mutations was confirmed in adult MLL-r AML. KRAS mutations were associated with adverse prognoses in pediatric patients with both high-risk (MLLT10+MLLT4+MLLT1; n = 60) and intermediate-to-low-risk (MLLT3+ELL+others; n = 100) MLL fusions. The prognosis did not differ significantly between patients with non-MLL-r AML with KRAS-WT or KRAS-MT. Multivariate analysis showed the presence of a KRAS mutation to be an independent prognostic factor for EFS (hazard ratio [HR], 2.21; 95% confidence interval [CI], 1.35-3.59; P = .002) and OS (HR, 1.85; 95% CI, 1.01-3.31; P = .045) in MLL-r AML. The mutation is a distinct adverse prognostic factor in MLL-r AML, regardless of risk subgroup, and is potentially useful for accurate treatment stratification. This trial was registered at the UMIN (University Hospital Medical Information Network) Clinical Trials Registry (UMIN-CTR; http://www.umin.ac.jp/ctr/index.htm) as #UMIN000000511.

The role of EVI1 gene quantification in AML patients with 11q23/MLL rearrangement after allogeneic hematopoietic stem cell transplantation

It remains unclear about the role of the EVI1 gene in AML patients with 11q23/MLL rearrangement (MLL-r AML) undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). We analyzed the clinical value of EVI1 gene quantification in 96 MLL-r AML patients. High EVI1 expression was found in 73% (70/96) of MLL-r AML patients, and EVI1-high MLL-r AML patients were characterized by high WBC counts (P = 0.046) and low platelet counts (P < 0.001) and commonly had t(6;11) (P = 0.032). In addition, a significant difference was observed in the SETD2 gene mutation between the EVI1 high and low groups (0% vs. 50%, P < 0.001). EVI1-high MLL-r AML patients had worse 2-year OS (49.8% vs. 79.7%, P = 0.01) and 2-year PFS (40.2% vs. 68.1%, P = 0.014) than EVI1-low patients. In 57 MLL-r AML patients undergoing allo-HSCT, poorer 2-year PFS (48.6% vs. 72.4%, P = 0.039) and higher CIR (33.2% vs. 11.1%, P = 0.035) were observed in the EVI1-high patients. Multivariate analysis revealed that pre-EVI1⁺ was the sole independent factor of high CIR (P = 0.035, HR = 4.97, 95% CI: 1.12-22.04). EVI1⁺ at 100 days post allo-HSCT was associated with a significantly higher 2-year CIR (P = 0.017). The quantification of the EVI1 gene could be used as an additional marker for early predicting relapse in allo-HSCT MLL-r AML patients.

Transcriptome analysis offers a comprehensive illustration of the genetic background of pediatric acute myeloid leukemia

Recent advances in the genetic understanding of acute myeloid leukemia (AML) have improved clinical outcomes in pediatric patients. However, ∼40% of patients with pediatric AML relapse, resulting in a relatively low overall survival rate of ∼70%. The objective of this study was to reveal the comprehensive genetic background of pediatric AML. We performed transcriptome analysis (RNA sequencing [RNA-seq]) in 139 of the 369 patients with de novo pediatric AML who were enrolled in the Japanese Pediatric Leukemia/Lymphoma Study Group AML-05 trial and investigated correlations between genetic aberrations and clinical information. Using RNA-seq, we identified 54 in-frame gene fusions and 1 RUNX1 out-of-frame fusion in 53 of 139 patients. Moreover, we found at least 258 gene fusions in 369 patients (70%) through reverse transcription polymerase chain reaction and RNA-seq. Five gene rearrangements were newly identified, namely, NPM1-CCDC28A, TRIP12-NPM1, MLLT10-DNAJC1, TBL1XR1-RARB, and RUNX1-FNBP1. In addition, we found rare gene rearrangements, namely, MYB-GATA1, NPM1-MLF1, ETV6-NCOA2, ETV6-MECOM, ETV6-CTNNB1, RUNX1-PRDM16, RUNX1-CBFA2T2, and RUNX1-CBFA2T3. Among the remaining 111 patients, KMT2A-PTD, biallelic CEBPA, and NPM1 gene mutations were found in 11, 23, and 17 patients, respectively. These mutations were completely mutually exclusive with any gene fusions. RNA-seq unmasked the complexity of gene rearrangements and mutations in pediatric AML. We identified potentially disease-causing alterations in nearly all patients with AML, including novel gene fusions. Our results indicated that a subset of patients with pediatric AML represent a distinct entity that may be discriminated from their adult counterparts. Based on these results, risk stratification should be reconsidered.

Downregulation of EVI1 Expression Inhibits Cell Proliferation and Induces Apoptosis in Hilar Cholangiocarcinoma via the PTEN/AKT Signalling Pathway

Aims: Hilar cholangiocarcinoma (HCCA) is a tumour with high malignancy, low surgical resection potential, and a poor prognosis. Ecotropic Viral Integration site 1 (EVI1) is a transcriptional regulator that has been proven to be associated with tumourigenesis and progression in many human solid tumours. However, the expression of EVI1 and its role in HCCA progression remain unclear. The aim of this study was to clarify the association between EVI1 expression and clinical outcomes in patients with HCCA.

Methods: The expression of EVI1 in HCCA tissue samples and cell lines was examined by quantitative real-time PCR (qRT-PCR), Western blotting, and immunohistochemistry (IHC). Kaplan-Meier analysis was used for survival analysis. A log-rank test was performed for univariate analysis of survival, and a Cox regression model was utilized for multivariate analysis of survival. Cell proliferation was measured by cell counting kit-8 (CCK-8), colony formation, and 5-ethynyl-2'-deoxyuridine (EdU) assays. The cell cycle was evaluated by flow cytometry. Cell apoptosis was detected by flow cytometry and a terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labelling (TUNEL) assay. In vivo tumour growth was observed for xenografts in nude mice.

Results: EVI1 expression was upregulated in HCCA tissue samples and correlated with a poor prognosis. In clinical specimens, the expression of EVI1 correlated with tumour histological grade and tumour size. Knocking down EVI1 expression reduced HCCA cell proliferation, blocked cell cycle progression, and promoted apoptosis in vitro and in vivo. Furthermore, we found that EVI1 could regulate the AKT signalling pathway by regulating PTEN levels in HCCA.

Conclusion: Our data revealed that EVI1 played important roles in HCCA tumourigenesis and development. Our findings suggest that EVI1 may be a potentially useful therapeutic target in HCCA.

EVI1 triggers metabolic reprogramming associated with leukemogenesis and increases sensitivity to L-asparaginase

Metabolic reprogramming of leukemia cells is important for survival, proliferation, and drug resistance under conditions of metabolic stress in the bone marrow. Deregulation of cellular metabolism, leading to development of leukemia, occurs through abnormally high expression of transcription factors such as MYC and Ecotropic Virus Integration site 1 protein homolog (EVI1). Overexpression of EVI1 in adults and children with mixed lineage leukemia-rearrangement acute myeloid leukemia (MLL-r AML) has a very poor prognosis. To identify a metabolic inhibitor for EVI1-induced metabolic reprogramming in MLL-r AML, we used an XFp extracellular flux analyzer to examine metabolic changes during leukemia development in mouse models of AML expressing MLL-AF9 and Evi1 (Evi1/MF9). Oxidative phosphorylation (OXPHOS) in Evi1/MF9 AML cells accelerated prior to activation of glycolysis, with a higher dependency on glutamine as an energy source. Furthermore, EVI1 played a role in glycolysis as well as driving production of metabolites in the tricarboxylic acid cycle. L-asparaginase (L-asp) exacerbated growth inhibition induced by glutamine starvation and suppressed OXPHOS and proliferation of Evi1/MF9 both in vitro and in vivo; high sensitivity to L-asp was caused by low expression of asparagine synthetase (ASNS) and L-asp-induced suppression of glutamine metabolism. In addition, samples from patients with EVI1⁺MF9 showed low ASNS expression, suggesting that it is a sensitive marker of L-asp treatment. Clarification of metabolic reprogramming in EVI1⁺ leukemia cells may aid development of treatments for EVI1⁺MF9 refractory leukemia.

Patients aged less than 3 years with acute myeloid leukaemia characterize a molecularly and clinically distinct subgroup

Although infants (age <1 year) with acute myeloid leukaemia (AML) have unique characteristics and are vulnerable to chemotherapy, children aged 1-2 years with AML may have characteristics similar to that of infants. Thus, we analysed 723 paediatric AML patients treated on the Japanese AML99 and AML-05 trials to identify characteristics of younger children. We identified patients aged <3 years (the younger group) as a distinct subgroup. KMT2A-rearrangement (KMT2A-R), CBFA2T3-GLIS2, CBFB-MYH11 and NUP98-KDM5A were frequently found in the younger group. Prognostic analyses revealed poor 5-year overall survival (OS), event-free survival (EFS) and cumulative incidence of relapse (CIR) in patients with CBFA2T3-GLIS2 (42%, 17% and 83%, respectively) and those with NUP98-KDM5A (33%, 17% and 83%, respectively). Additionally, we identified KMT2A-R and CBFB-MYH11 as age-specific prognostic markers. Regarding KMT2A-R, the younger group had significantly better OS, EFS and CIR than the older group (aged 3 to <18 years) (P = 0·023, 0·011 and <0·001, respectively). Conversely, concerning CBFB-MYH11, the younger group had significantly poor EFS and CIR than the older group (each P < 0·001), suggesting that certain molecular markers are linked to different prognoses according to age. Therefore, we characterized patients <3 years as a distinct subgroup of paediatric AML.

Whole transcriptome sequencing reveals a KMT2A-USP2 fusion in infant acute myeloid leukemia

Infant acute lymphoblastic leukemia with lysine (K)-specific methyltransferase 2A (KMT2A) rearrangements usually has a poor prognosis regardless of the fusion partners of KMT2A. However, the prognosis of pediatric acute myeloid leukemia (AML) with KMT2A rearrangements depends on its translocation partners. We herein report the case of a 9-month-old boy with a KMT2A-USP2 fusion, which required diagnosis by whole transcriptome sequencing after the failure of detection of known translocation partners by conventional screening approaches. As this first report of a patient with AML with a KMT2A-USP2 fusion illustrates, identification of the partners in all patients with KMT2A-rearranged AML is critical to elucidate the outcomes associated with specific rearrangements and to develop appropriate treatment strategies. Moreover, development of additional methods to detect specific translocation partners of KMT2A and leukemia-specific targeting drugs is important to improve further the outcomes of KMT2A-rearranged AML.

The clinical and prognostic significance of FIS1, SPI1, PDCD7 and Ang2 expression levels in acute myeloid leukemia

OBJECTIVES

The marked heterogeneity of acute myeloid leukemia (AML) renders precisely predicting patient prognosis extremely difficult. Genetic alterations, fusions and mutations, may result in misexpression of key genes in AML. We aimed to investigate the expression patterns of 4 novel genes; FIS1, SPI1, PDCD7 and Ang2 to determine their potential prognostic role in AML patients.

METHODS

Bone marrow mononuclear cells were analyzed for of FIS1, SPI1, PDCD7 and Ang2 expression levels by real-time quantitative PCR as well as of FLT3/ITD and NPM1 mutations in 100 newly diagnosed cytogenetically normal (CN-AML) patients, and 100 non-malignant controls.

RESULTS

FIS1, SPI1, PDCD7 and Ang2 were significantly overexpressed in CN-AML patients (p < 0.001). Their high expression levels were significantly associated with lower complete remission (CR) rate, shorter relapse-free survival (RFS) and overall survival (OS). On multivariate analysis, high FIS1 expression showed a significant impact on CR response after induction therapy (OR = 88.777, 95% C.I: 2.85-2765.78, p = 0.011) while high PDCD7 appeared to be an independent risk factor for RFS (HR = 5.107, 95% C.I: 1.731-15.066, p = 0.003) and OS (HR = 7.353, 95% C.I: 1.859-29.079, p = 0.004) in CN-AML patients.

CONCLUSIONS

FIS1 and PDCD7 expression are considered independent risk factors and should be integrated into the current AML stratification system.

Prognostic Value of EVI1 Expression in Pediatric Acute Myeloid Leukemia: A Systematic Review

Acute myeloid leukemia (AML) as a distortion of blood cells involves the differ entiation of hematopoietic stem cells. Several studies established the irregular over expression of specific genes is a common finding in patients with AML. The ectopic viral integration site-1 (EVI1) gene is a protooncogene subject to alternative splicing, and encodes a zincfinger protein that acts as a transcriptional regulator in early devel opment. Forced overexpression of EVI1 in hematopoietic progenitors later induced a myeloid differentiation block. The current review aimed at determining the prognos tic value of EVI1 expression in patients with AML in the age range of one month to fifteen years. The scientific databases including PubMed, Google Scholar, EMBASE, Scopus, and ISI published up to January 2016 were searched using the conformity keywords and a total of four articles were studied. Three articles declared higher overexpression of EVI1 in patients with mixed-lineage leukemia (MLL) rearrangements. The percentage of overall survival (OS), reported in two articles, decreased in AML patients with high EVI1 expression. A study reported that the relationship between EVI1 expression and OS was negligible in cases with and without EVI1 expression. Another study showed significant differences in event free survival (EFS) and OS in the group of patients with positive MLL-AF9 between EVI1+ and EVI1patients. The current study revealed that high EVI1 expression was not a poor prognostic factor in pediatric patients with AML. And this gene expression was mainly prognostic concomitantly by other factors such as MLL rearrangement, MEL1 expression, and white blood cell (WBC) count.

Multiplex fusion gene testing in pediatric acute myeloid leukemia

BACKGROUND

Gene abnormalities, particularly chromosome rearrangements generating gene fusion, are associated with clinical characteristics and prognosis in pediatric acute myeloid leukemia (AML). Karyotyping is generally performed to enable risk stratification, but the results are not always consistent with those of reverse transcription-polymerase chain reaction (RT-PCR), and more accurate and rapid methods are required.

METHODS

A total of 487 samples from de novo AML patients enrolled in the Japanese Pediatric Leukemia/Lymphoma Study Group (JPLSG) AML-05 study (n = 448), and from acute promyelocytic leukemia (APL) patients enrolled in the JPLSG AML-P05 study (n = 39) were available for this investigation. Multiplex quantitative RT-PCR was performed to detect eight important fusion genes: AML1(RUNX1)-ETO(RUNX1T1), CBFB-MYH11, MLL(KMT2A)-AF9(MLLT3), MLL-ELL, MLL-AF6(MLLT4), FUS(TLS)-ERG, NUP98-HOXA9, and PML-RARA.

RESULTS

Fusion genes were detected in 207 (46.2%) of the 448 AML-05 patient samples. After exclusion of two samples with PML-RARA, no chromosomal abnormalities were identified on karyotyping in 19 of 205 patients (9.3%) positive for fusion genes on RT-PCR. Fusion genes were confirmed on fluorescence in situ hybridization (FISH) in 11 of these 19 patients. In contrast, fusion genes were detected in 37 of 39 patients (94.9%) from the AML-P05 study, and 33 of these results were consistent with the karyotyping. There were discrepancies in four patients (10.8%), three with normal karyotypes and one in whom karyotyping was not possible. All four of these patients were PML-RARA positive on FISH.

CONCLUSIONS

Multiplex quantitative RT-PCR-based fusion gene screening may be effective for diagnosis of pediatric AML.

Gene mutational pattern and expression level in 560 acute myeloid leukemia patients and their clinical relevance

Background

Cytogenetic aberrations and gene mutations have long been regarded as independent prognostic markers in AML, both of which can lead to misexpression of some key genes related to hematopoiesis. It is believed that the expression level of the key genes is associated with the treatment outcome of AML.

Methods

In this study, we analyzed the clinical features and molecular aberrations of 560 newly diagnosed non-M3 AML patients, including mutational status of CEBPA, NPM1, FLT3, C-KIT, NRAS, WT1, DNMT3A, MLL-PTD and IDH1/2, as well as expression levels of MECOM, ERG, GATA2, WT1, BAALC, MEIS1 and SPI1.

Results

Certain gene expression levels were associated with the cytogenetic aberration of the disease, especially for MECOM, MEIS1 and BAALC. FLT3, C-KIT and NRAS mutations contained conversed expression profile regarding MEIS1, WT1, GATA2 and BAALC expression, respectively. FLT3, DNMT3A, NPM1 and biallelic CEBPA represented the mutations associated with the prognosis of AML in our group. Higher MECOM and MEIS1 gene expression levels showed a significant impact on complete remission (CR) rate, disease free survival (DFS) and overall survival (OS) both in univariate and multivariate analysis, respectively; and an additive effect could be observed. By systematically integrating gene mutational status results and gene expression profile, we could establish a more refined system to precisely subdivide AML patients into distinct prognostic groups.

Conclusions

Gene expression abnormalities contained important biological and clinical informations, and could be integrated into current AML stratification system.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-017-1279-4) contains supplementary material, which is available to authorized users.

Purification of leukemic blast cells from blood smears using laser microdissection

In treatment of acute myeloid leukemia (AML), prognostic factors, including gene mutation and abnormal gene expression, enable risk stratification of patients. However, in the case of a small proportion of leukemic blast cells, such as AML associated with Down syndrome (AML-DS), it is not possible to examine prognostic factors precisely due to the large proportion of normal cells. Here, we present a novel method for examining prognostic factors by making a smear on a membrane slide glass from a small amount of diagnostic specimen and collecting highly pure leukemic blast cells by laser microdissection (LMD). We verified the effectiveness of this method using 10% KPAM1 cell line suspension and peripheral blood containing 20% blast cells obtained from a patient with transient abnormal myelopoiesis (TAM). After making blood smears, approximately 100 cells were collected and analyzed by direct sequencing. Frameshift mutations (2 bp deletion and 17 bp duplication, respectively) in GATA-1 were detected in each sample, suggesting KPAM1 and TAM blast cells were accurately purified. This novel method enables us to precisely examine prognostic factors in many cases, even in cases with a small proportion of leukemic blast cells or small specimens to preserve.

The MDS and EVI1 complex locus (MECOM) isoforms regulate their own transcription and have different roles in the transformation of hematopoietic stem and progenitor cells

Transcriptional activation of the EVI1 oncogene (3q26) leads to aggressive forms of human acute myeloid leukemia (AML). However, the mechanism of EVI1-mediated leukemogenesis has not been fully elucidated. Previously, by characterizing the EVI1 promoter, we have shown that RUNX1 and ELK1 directly regulate EVI1 transcription. Intriguingly, bioinformatic analysis of the EVI1 promoter region identified the presence of several EVI1 potential binding sites. Thus, we hypothesized that EVI1 could bind to these sites regulating its own transcription. In this study, we show that there is a functional interaction between EVI1 and its promoter, and that the different EVI1 isoforms (EVI1-145kDa, EVI1-Δ324 and MDS1-EVI1) regulate the transcription of EVI1 transcripts through distinct promoter regions. Moreover, we determine that the EVI1-145kDa isoform activates EVI1 transcription, whereas EVI1-Δ324 and MDS1-EVI1 act as repressors. Finally, we demonstrate that these EVI1 isoforms are involved in cell transformation; functional experiments show that EVI1-145kDa prolongs the maintenance of hematopoietic stem and progenitor cells; conversely, MDS1-EVI1 repressed hematopoietic stem and progenitor colony replating capacity. We demonstrate for the first time that EVI1 acts as a regulator of its own expression, highlighting the complex regulation of EVI1, and open new directions to better understand the mechanisms of EVI1 overexpressing leukemias.

[EVI1 expression, clinical and cytogenetical characteristics in 447 patients with acute myeloid leukemia]

Objective: To investigate EVI1 expression and its associated clinical and cytogenetic characteristics in 447 acute myeloid leukemia (AML) patients. Methods: EVI1 expressions were measured in 447 AML cases from Jan. 2007 to Apr. 2015 to couple with clinical, cytogenetic and mutations' characteristics to summarize the features of AMLs with high EVI1 expression. Results: 17.9% of AML were high EVI1 expression (EVI1 +), and the remainder low EVI1 expression (EVI1-). No significant differences between the two groups in terms of age, sex, hemoglobin level, white blood cell count and platelet count were observed. More M0, M5 and M6 subtypes were observed in EVI1+ group (P= 0.027, 0.004 and 0.011, respectively). Cytogenetic abnormalities of 11q15, 11q23/MLL, 3q26, -7/7q- and t (9;11) were observed more frequently in EVI1 + group (P<0.001, <0.001, <0.001, <0.001, =0.014, respectively). Normal karyotype, inv (16), t (8;21) were observed more frequent in EVI1- group (P=0.001, 0.009, 0.002, respectively). EVI1 + was more observed in high risk cytogenetics. Mutation of NPM1 was more observed in EVI1- group (P <0.001). Remission rate in EVI1 + group was significantly lower than EVI1- group (P<0.001). Leukemia-free survival was improved in EVI1 + AML patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). Conclusions: High EVI1 expression was more observed in FAB subgroup M5, harbored more cytogenetic abnormalities of 11p15, 11q23/MLL, 3q26 rearrangement, -7/7q- and t (9;11). Remission rate of high EVI1 expression AML was lower, which could be improved by allo-HSCT.

CXCR4 Overexpression is a Poor Prognostic Factor in Pediatric Acute Myeloid Leukemia With Low Risk: A Report From the Japanese Pediatric Leukemia/Lymphoma Study Group

BACKGROUND

Overexpression of CXC chemokine receptor 4 (CXCR4+) is a poor prognostic factor in adult acute myeloid leukemia (AML); however, its prognostic significance in pediatric AML is unclear.

PROCEDURE

This retrospective study examined the prognostic significance of CXCR4+ in pediatric AML patients enrolled in the Japanese Pediatric Leukemia/Lymphoma Study Group AML-05 study.

RESULTS

In the total cohort (n = 248), no significant differences were observed between CXCR4+ patients (n = 81) and CXCR4- patients (n = 167) in terms of 3-year overall survival (OS) (69.4% vs. 75.2%, P = 0.44). However, there was a significant difference in 3-year OS between CXCR4+ and CXCR4- patients in the low-risk (LR) group (n = 93; 79.2% vs. 98.3%, P = 0.007). CXCR4+ patients in the t(8;21) AML without KIT mutation group had a significantly worse 3-year OS than CXCR4- patients (n = 44; 76.1% vs. 100.0%, P = 0.01). Multivariate Cox regression analysis identified CXCR4+ as a poor prognostic factor for OS in LR AML patients (hazard ratio, 11.47; P = 0.01). Consistent with the data for survival analysis, CXCR4+ patients in the t(8;21) AML group had a higher incidence of splenomegaly than CXCR4- patients (25.9% vs. 5.9%, P = 0.03).

CONCLUSIONS

These results suggest that CXCR4+ is a poor prognostic factor for LR patients, particularly t(8;21) patients without KIT mutation. The poor outcome was only applicable to OS, not relapse-free survival (RFS); thus, CXCR4+ may be associated with a poor prognosis after recurrence. Intensive therapy, including administration of CXCR4 antagonists, may be promising for pediatric AML patients with LR.

Predictive value of high EVI1 expression in AML patients undergoing myeloablative allogeneic hematopoietic stem cell transplantation in first CR

The EVI1 gene is a transcriptional regulator of hematopoietic stem cell self renewal and its overexpression is associated with adverse prognosis in de novo AML. Whether the overexpression of EVI1 also predicts poor outcome of AML patients undergoing myeloablative allogeneic hematopoietic stem cell transplantation (allo-HSCT) in first CR (CR1) is still unclear. Thirty-two (21.2%) out of 151 patients were categorized as high EVI1 expression (EVI1+), and 119 (78.8%) patients were categorized as low EVI1 expression (EVI1-). The frequency of EVI1+ was much higher in the adverse-risk group than the intermediate-risk group (53% vs 19%, P=0.005). EVI1+ patients were significantly likely to harbor with translocations involving the MLL gene on 11q23 (8/9). Significantly poor results were observed in the EVI1+ cohort in terms of leukemia-free survival (LFS) (in 24 months 52.6 vs 71.0%, P=0.027), overall survival (OS) (in 24 months 52.8 vs 72.4%, P=0.012), and cumulative incidence of relapse (in 24 months 39.5 vs 22.5%, P=0.013). Multivariable analysis revealed that low EVI1 expression as an independent prognostic factor favoring LFS (hazards ratio=0.47, 95% confidence interval 0.26-0.86, P=0.01) but not OS. Our results indicate high EVI1 expression might predict high risk of relapse in AML patients undergoing myeloablative allo-HSCT in CR1.

Review: Aberrant EVI1 expression in acute myeloid leukaemia

Deregulated expression of the ecotropic virus integration site 1 (EVI1) gene is the molecular hallmark of therapy-resistant myeloid malignancies bearing chromosomal inv(3)(q21q26·2) or t(3;3)(q21;q26·2) [hereafter referred to as inv(3)/t(3;3)] abnormalities. EVI1 is a haematopoietic stemness and transcription factor with chromatin remodelling activity. Interestingly, the EVI1 gene also shows overexpression in 6-11% of adult acute myeloid leukaemia (AML) cases that do not carry any 3q aberrations. Deregulated expression of EVI1 is strongly associated with monosomy 7 and 11q23 abnormalities, which are known to be associated with poor response to treatment. However, EVI1 overexpression has been revealed as an important independent adverse prognostic marker in adult AML and defines distinct risk categories in 11q23-rearranged AML. Recently, important progress has been made in the delineation of the mechanism by which EVI1 becomes deregulated in inv(3)/t(3;3) as well as the cooperating mutations in this specific subset of AML with dismal prognosis.

The role of EVI-1 in normal hematopoiesis and myeloid malignancies (Review)

Ecotropic virus integration site-1 (EVI-1) gene, locus on chromosome 3 (3q26.2) in the human genome, was first found in the AKXD strain of mice, in a model of retrovirus-induced acute myeloid leukemia (AML) established twenty years ago. Since then, EVI-1 was regarded as one of the most invasive proto-oncogenes in human leukemia. EVI-1 can encode a unique zinc-finger protein of 145 kDa that can bind with DNA, and its overexpression was closely related to human hemopoietic diseases. Furthermore, accumulating research indicates that EVI-1 is involved in the differentiation, apoptosis and proliferation of leukemia cells. The present review focuses on the biochemical properties of EVI-1 which plays a role in myeloid malignancies.

Collaborative Efforts Driving Progress in Pediatric Acute Myeloid Leukemia

Diagnosis, treatment, response monitoring, and outcome of pediatric acute myeloid leukemia (AML) have made enormous progress during the past decades. Because AML is a rare type of childhood cancer, with an incidence of approximately seven occurrences per 1 million children annually, national and international collaborative efforts have evolved. This overview describes these efforts and includes a summary of the history and contributions of each of the main collaborative pediatric AML groups worldwide. The focus is on translational and clinical research, which includes past, current, and future clinical trials. Separate sections concern acute promyelocytic leukemia, myeloid leukemia of Down syndrome, and relapsed AML. A plethora of novel antileukemic agents that have emerged, including new classes of drugs, are summarized as well. Finally, an important aspect of the treatment of pediatric AML--supportive care--and late effects are discussed. The future is bright, with a wide range of emerging innovative therapies and with more and more international collaboration that ultimately aim to cure all children with AML, with fewer adverse effects and without late effects.