Acute erythroleukemia: diagnosis and management

Design, Synthesis, and Anti-Leukemic Evaluation of a Series of Dianilinopyrimidines by Regulating the Ras/Raf/MEK/ERK and STAT3/c-Myc Pathways

Although the long-term survival rate for leukemia has made significant progress over the years with the development of chemotherapeutics, patients still suffer from relapse, leading to an unsatisfactory outcome. To discover the new effective anti-leukemia compounds, we synthesized a series of dianilinopyrimidines and evaluated the anti-leukemia activities of those compounds by using leukemia cell lines (HEL, Jurkat, and K562). The results showed that the dianilinopyrimidine analog H-120 predominantly displayed the highest cytotoxic potential in HEL cells. It remarkably induced apoptosis of HEL cells by activating the apoptosis-related proteins (cleaved caspase-3, cleaved caspase-9 and cleaved poly ADP-ribose polymerase (PARP)), increasing apoptosis protein Bad expression, and decreasing the expression of anti-apoptotic proteins (Bcl-2 and Bcl-xL). Furthermore, it induced cell cycle arrest in G2/M; concomitantly, we observed the activation of p53 and a reduction in phosphorylated cell division cycle 25C (p-CDC25C) / Cyclin B1 levels in treated cells. Additionally, the mechanism study revealed that H-120 decreased these phosphorylated signal transducers and activators of transcription 3, rat sarcoma, phosphorylated cellular RAF proto-oncogene serine / threonine kinase, phosphorylated mitogen-activated protein kinase kinase, phosphorylated extracellular signal-regulated kinase, and cellular myelocytomatosis oncogene (p-STAT3, Ras, p-C-Raf, p-MEK, p-MRK, and c-Myc) protein levels in HEL cells. Using the cytoplasmic and nuclear proteins isolation assay, we found for the first time that H-120 can inhibit the activation of STAT3 and c-Myc and block STAT3 phosphorylation and dimerization. Moreover, H-120 treatment effectively inhibited the disease progression of erythroleukemia mice by promoting erythroid differentiation into the maturation of erythrocytes and activating the immune cells. Significantly, H-120 also improved liver function in erythroleukemia mice. Therefore, H-120 may be a potential chemotherapeutic drug for leukemia patients.

Survival after Pure (Acute) Erythroid Leukemia in the United States: A SEER-Based Study

BACKGROUND

Acute erythroid leukemia (AEL), also known as pure erythroid leukemia, is a rare subtype of acute myeloid leukemia (AML) characterized by the proliferation of malignant erythroid precursors. Outcome data at the population level are scarce.

METHODS

We performed a retrospective analysis of the Surveillance Epidemiology and End Results (SEER) database. All cases with a histologically confirmed diagnosis of acute (pure) erythroid leukemia during the period of 2000-2019 were included in the study. The Kaplan-Meier method was used to perform survival analysis. The significance of differences between overall survival (OS) was analyzed using the log-rank test.

RESULTS

In total, 968 patients were included in the study. The median age was 68 years (range 0-95), 62% of patients were males, and 62.5% (n = 605) were treated with chemotherapy. The median OS for <18, 18-49, 50-64, 65-79 and 80+ age groups was 69, 18, 8, 3 and 1 month, respectively (p < 0.0001). Patients who received chemotherapy had significantly improved OS compared to patients who did not, among both adults (p < 0.0001) and children (p = 0.004). There were no significant differences in OS based on sex, race, ethnicity and median household income. Median OS for adults diagnosed in 2000-2004, 2005-2009, 2010-2014, 2015-2019 was 4, 6, 6 and 3 months, respectively, with no significant differences in OS between these groups.

CONCLUSION

AEL occurs in all age groups but is most common in the elderly. Outcomes are poor with current chemotherapeutic agents, with no improvement in the last two decades. This study stresses the urgent need for investigational agents.

Erythroleukemia: an Update

PURPOSE OF THE REVIEW

Acute erythroleukemia (AEL) is a rare form of acute myeloid leukemia recognized by erythroblastic proliferation. Many controversies remain around diagnosis influencing prognostic and therapeutic implications relating to this unique leukemia subset.

RECENT FINDINGS

The 2016 WHO classification includes more clear and restrictive diagnostic criteria for AEL. Primary acute erythroid leukemia is associated with complex and high-risk karyotypes including chromosomes 5q and 7q abnormalities. Mutational data shows that AEL is characterized by far lower NPM1 and FLT3-ITD mutation rates and higher mutational rates in TP53 compared with other AML subtypes. Hypomethylating agents have shown therapeutic value in AEL. In this article, we discuss the evolving diagnostic concepts of erythroleukemia, genomics, clinical outcome, and promising therapeutic targets through an appraisal of the current literature.

Modeling and targeting of erythroleukemia by hematopoietic genome editing

Acute erythroid leukemia (AEL) is characterized by a distinct morphology, mutational spectrum, lack of preclinical models, and poor prognosis. Here, using multiplexed genome editing of mouse hematopoietic stem and progenitor cells and transplant assays, we developed preclinical models of AEL and non-erythroid acute leukemia and describe the central role of mutational cooperativity in determining leukemia lineage. Different combination of mutations in Trp53, Bcor, Dnmt3a, Rb1, and Nfix resulted in the development of leukemia with an erythroid phenotype, accompanied by the acquisition of alterations in signaling and transcription factor genes that recapitulate human AEL by cross-species genomic analysis. Clonal expansion during tumor evolution was driven by mutational cooccurrence, with clones harboring a higher number of founder and secondary lesions (eg, mutations in signaling genes) showing greater evolutionary fitness. Mouse and human AEL exhibited deregulation of genes regulating erythroid development, notably Gata1, Klf1, and Nfe2, driven by the interaction of mutations of the epigenetic modifiers Dnmt3a and Tet2 that perturbed methylation and thus expression of lineage-specific transcription factors. The established mouse leukemias were used as a platform for drug screening. Drug sensitivity was associated with the leukemia genotype, with the poly (ADP-ribose) polymerase inhibitor talazoparib and the demethylating agent decitabine efficacious in Trp53/Bcor-mutant AEL, CDK7/9 inhibitors in Trp53/Bcor/Dnmt3a-mutant AEL, and gemcitabine and bromodomain inhibitors in NUP98-KDM5A leukemia. In conclusion, combinatorial genome editing has shown the interplay of founding and secondary genetic alterations in phenotype and clonal evolution, epigenetic regulation of lineage-specific transcription factors, and therapeutic tractability in erythroid leukemogenesis.

Development of a MEL Cell-Derived Allograft Mouse Model for Cancer Research

Murine erythroleukemia (MEL) cells are often employed as a model to dissect mechanisms of erythropoiesis and erythroleukemia in vitro. Here, an allograft model using MEL cells resulting in splenomegaly was established to develop a diagnostic model for isolation/quantification of metastatic cells, anti-cancer drug screening, and evaluation of the tumorigenic or metastatic potentials of molecules in vivo. In this animal model, circulating MEL cells from the blood stream were successfully isolated and quantified with an additional in vitro cultivation step. In terms of the molecular-pathological analysis, we were able to successfully evaluate the functional discrimination between methyl-CpG-binding domain 2 (Mbd2) and p66α in erythroid differentiation, and tumorigenic potential in spleen and blood stream of allograft model mice. In addition, we found that the number of circulating MEL cells in anti-cancer drug-treated mice was dose-dependently decreased. Our data demonstrate that the newly established allograft model is useful to dissect erythroleukemia pathologies and non-invasively provides valuable means for isolation of metastatic cells, screening of anti-cancer drugs, and evaluation of the tumorigenic potentials.

Induction of apoptosis and necrosis in human acute erythroleukemia cells by inhibition of long non-coding RNA PVT1

Recent advances in molecular medicine have proposed new therapeutic strategies for cancer. One of the molecular research lines for the diagnosis and treatment of cancer is the use of long non-coding RNAs (LncRNAs) which are a class of non-coding RNA molecules longer than 200 base pairs in length that act as the key regulator of gene expression. Different aspects of cellular activities like cell growth, proliferation, differentiation, apoptosis and migration are regulated by lncRNAs. In various cancers, aberrant expression of lncRNAs has been reported. One of the lncRNAs that showed upregulation in human acute myeloid leukemia (AML) is lncRNA plasmacytoma variant translocation 1 (PVT1). Here, we performed blockage of lncRNA PVT1 in human acute erythroleukemia (AEL) cell line (KG1) using antisense LNA GapmeRs. Then, at different time points (24, 48 and 72 hours) after transfection, qRT‑real‑time PCR and AnnexinV/Propidium Iodide staining assay were performed. The data were processed using the ANOVA test. At all three time points, the ratio of apoptotic cells in the PVT1 antisense LNA GapmeRs treated group was higher than the other groups. The ratio of necrotic cells in the antisense LNA GapmeRs group was also higher than the other groups. These assessments show that inhibition of lncRNA PVT1 could significantly induce apoptosis and necrosis in KG1 cells. Our findings can be used in translational medicine for future investigation in acute erythroleukemia and treatment approach based on antisense therapy.

An analysis of 97 previously diagnosed de novo adult acute erythroid leukemia patients following the 2016 revision to World Health Organization classification

Background

The incidence of acute erythroid leukemia subtype (AEL) is rare, accounting for 5% of cases of acute myeloid leukemia (AML), and the outcome is dismal. However, in 2016 revision to the WHO classification, the subcategory of AEL has been removed. Myeloblasts are redefined as the percentage of total marrow cells, not non-erythroid cells. Therefore, the previously diagnosed AEL cases are currently diagnosed as AML or myelodyspalstic syndrome (MDS) according to new criteria.

Methods

We respectively reviewed cases of 97 de novo previously diagnosed AEL and all the patients were diagnosed as AML or MDS according to the new classification scheme, and then the clinical characteristics of these two subtypes were compared. Statistical analyses were performed by SPSS software version 18.0.

Results

The median age was 37 years-old, the two-thirds of previous AEL cases were diagnosed as MDS, and there was no obvious difference between two subtypes except for male/female ratio and age. Cytogenetic, rather than MDS/AML subtypes, can better represent the prognostic factor of previously diagnosed AEL patients. When the cytogenetic risk of patients belonged to MRC intermediate category and age were below 40 years-old in previous AEL cases, the patients who received induction chemotherapy without transplantation had a similar survival compared with the patients who underwent transplantation (3-year OS: 67.2% vs 68.5%).

Conclusions

Cytogenetic, rather than MDS/AML subtypes, can better represent the prognostic factor of previously diagnosed AEL patients. Transplantation was a better choice for those whose cytogenetic category was unfavorable.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3528-6) contains supplementary material, which is available to authorized users.

Clinical Outcomes of 217 Patients with Acute Erythroleukemia According to Treatment Type and Line: A Retrospective Multinational Study

Acute erythroleukemia (AEL) is a rare disease typically associated with a poor prognosis. The median survival ranges between 3-9 months from initial diagnosis. Hypomethylating agents (HMAs) have been shown to prolong survival in patients with myelodysplastic syndromes (MDS) and AML, but there is limited data of their efficacy in AEL. We collected data from 210 AEL patients treated at 28 international sites. Overall survival (OS) and PFS were estimated using the Kaplan-Meier method and the log-rank test was used for subgroup comparisons. Survival between treatment groups was compared using the Cox proportional hazards regression model. Eighty-eight patients were treated with HMAs, 44 front line, and 122 with intensive chemotherapy (ICT). ICT led to a higher overall response rate (complete or partial) compared to first-line HMA (72% vs. 46.2%, respectively; p ≤ 0.001), but similar progression-free survival (8.0 vs. 9.4 months; p = 0.342). Overall survival was similar for ICT vs. HMAs (10.5 vs. 13.7 months; p = 0.564), but patients with high-risk cytogenetics treated with HMA first-line lived longer (7.5 for ICT vs. 13.3 months; p = 0.039). Our results support the therapeutic value of HMA in AEL.

Response to treatment with azacitidine in children with advanced myelodysplastic syndrome prior to hematopoietic stem cell transplantation

Advanced myelodysplastic syndrome harbors a high risk of progression to acute myeloid leukemia and poor prognosis. In children, there is no established treatment to prevent or delay progression to leukemia prior to hematopoietic stem cell transplantation. Azacitidine is a hypomethylating agent, which was shown to slow progression to leukemia in adults with myelodysplastic syndrome. There is little data on the efficacy of azacitidine in children. We reviewed 22 pediatric patients with advanced myelodysplastic syndrome from a single center, diagnosed between January 2000 and December 2015. Of those, eight patients received off-label azacitidine before hematopoietic stem cell transplantation. A total of 31 cycles were administered and modification or delay occurred in four of them due to cytopenias, infection, nausea/vomiting, and transient renal impairment. Bone marrow blast percentages in azacitidine-treated patients decreased significantly from a median of 15% (range 9-31%) at the start of treatment to 5.5% (0-12%, P=0.02) before hematopoietic stem cell transplantation. Following azacitidine treatment, four patients (50%) achieved marrow remission, and none progressed. In contrast, three untreated patients (21.4%) had progressive disease characterized by >50% increase in blast counts or progression to leukemia. Azacitidine-treated patients had significantly increased 4-year event-free survival (P=0.04); predicted 4-year overall survival was 100% versus 69.3% in untreated patients (P=0.1). In summary, azacitidine treatment prior to hematopoietic stem cell transplantation was well tolerated in pediatric patients with advanced myelodysplastic syndrome, led to partial or complete bone marrow response in seven of eight patients (87.5%), and correlated with superior event-free survival in this cohort.

Computational design of peptide-Au cluster probe for sensitive detection of α(IIb)β3 integrin

We have designed a novel peptide-Au cluster probe to specifically bind to αIIbβ3 integrin. As indicated by molecular dynamics (MD) simulations, the binding mode of the native ligand of αIIbβ3 integrin, γC peptide, can be realized by the designed probe. More importantly, the peptide-Au probe can provide multiple coating peptides to form additional salt bridges with protein, and the binding stability of the probe is comparable to the native ligand. The designed probe was then successfully synthesized. The specific binding in a cellular environment was validated by colocalization analysis of confocal microscopy. In addition, the binding affinity was confirmed by atomic force microscopy (AFM) based single molecule force spectroscopy. Our results suggest the combination of computational design and experimental verification can be a useful strategy for the development of nanoprobes.

Berberis libanotica extract targets NF-κB/COX-2, PI3K/Akt and mitochondrial/caspase signalling to induce human erythroleukemia cell apoptosis

The aim of this study was to describe and understand the relationship between cyclooxygenase-2 (COX-2) expression and apoptosis rate in erythroleukemia cells after apoptosis induction by Berberis libanotica (Bl) extract. To achieve this goal we used erythroleukemia cell lines expressing COX‑2 (HEL cell line) or not (K562 cell line). Moreover, we made use of COX‑2 cDNA to overexpress COX‑2 in K562 cells. In light of the reported chemopreventive and chemosensitive effects of natural products on various tumor cells and animal models, we postulated that our Bl extract may mediate their effects through apoptosis induction with suppression of cell survival pathways. Our study is the first report on the specific examination of intrinsic apoptosis and Akt/NF-κB/COX‑2 pathways in human erythroleukemia cells upon Bl extract exposure. Even if Bl extract induced apoptosis of three human erythroleukemia cell lines, a dominant effect of Bl extract treatment on K562 cells was observed resulting in activation of the late markers of apoptosis with caspase-3 activation, PARP cleavage and DNA fragmentation. Whereas, we showed that Bl extract reduced significantly expression of COX‑2 by a dose-dependent manner in HEL and K562 (COX‑2+) cells. Furthermore, in regard to our results, it is clear that the simultaneous inhibition of Akt and NF-κB signalling can significantly contribute to the anticancer effects of Bl extract in human erythroleukemia cells. We observed that the Bl extract is clearly more active than the berberine alone on the induction of DNA fragmentation in human erythro-leukemia cells.

Cyclooxygenase-2 positively regulates Akt signalling and enhances survival of erythroleukemia cells exposed to anticancer agents

Cyclooxygenase-2 (COX-2) has been found to be highly expressed in many types of cancers and to contribute to tumorigenesis via the inhibition of apoptosis, increased angiogenesis and invasiveness. In hematological malignancies, COX-2 expression was found to correlate with poor patient prognosis. However, the exact role of COX-2 expression in these malignancies, and particularly in erythroleukemias, remains unclear. The aim of this work was to describe and understand the relationships between COX-2 expression and apoptosis rate in erythroleukemia cells after apoptosis induction by several anticancer agents. We used three different erythroleukemia cell lines in which COX-2 expression was modulated by transfection with either COX-2 siRNA or COX-2 cDNA. These cellular models were then treated with apoptosis inducers and apoptosis onset and intensity was followed. Cell signalling was evaluated in unstimulated transfected cells or after apoptosis induction. We found that COX-2 inhibition rendered erythroleukemia cells more sensitive to apoptosis induction and that in cells overexpressing COX-2 apoptosis induction was reduced. We demonstrated that COX-2 inhibition decreased the pro-survival Akt signalling and activated the negative regulator of Akt signalling, phosphatase and tensin homologue deleted on chromosome 10 (PTEN). Conversely, in COX-2 overexpressing cells, Akt signalling was activated and PTEN was inhibited. In these last cells, inhibition of casein kinase 2 or Akt signalling restored sensitivity to apoptotic agents. Our findings highlighted that COX-2 can positively regulate Akt signalling mostly through PTEN inhibition, partly via casein kinase 2 activation, and enhances survival of erythroleukemia cells exposed to anticancer agents.

Treatment of acute erythroleukemia with Azacitidine: A case series

Acute erythroleukemia (AEL) is a rare form of acute myeloid leukemia (AML) often associated with a poor prognosis. It is more frequent in elderly patients, limiting the use aggressive therapies. Azacitidine is a hypomethylating agent with recognized efficacy in high risk myelodysplasia and AML in the elderly. Here we report 5 cases of AEL treated with Azacitidine. The cohort included 4 men and 1 woman, median age 70. One patient had been refractory to intensive chemotherapy, the others received Azacitidine as first line. Treatment was well tolerated. Four patients achieved transfusion independence. Two patients achieved complete remission and 1 achieved partial remission. After a median follow up time of 20 months, the median survival of the cohort was 20 months. Three patients died of disease progression. These results confirm the therapeutic value of Azacitidine in AEL.

Transposon mutagenesis reveals cooperation of ETS family transcription factors with signaling pathways in erythro-megakaryocytic leukemia

To define genetic lesions driving leukemia, we targeted cre-dependent Sleeping Beauty (SB) transposon mutagenesis to the blood-forming system using a hematopoietic-selective vav 1 oncogene (vav1) promoter. Leukemias of diverse lineages ensued, most commonly lymphoid leukemia and erythroleukemia. The inclusion of a transgenic allele of Janus kinase 2 (JAK2)V617F resulted in acceleration of transposon-driven disease and strong selection for erythroleukemic pathology with transformation of bipotential erythro-megakaryocytic cells. The genes encoding the E-twenty-six (ETS) transcription factors Ets related gene (Erg) and Ets1 were the most common sites for transposon insertion in SB-induced JAK2V617F-positive erythroleukemias, present in 87.5% and 65%, respectively, of independent leukemias examined. The role of activated Erg was validated by reproducing erythroleukemic pathology in mice transplanted with fetal liver cells expressing translocated in liposarcoma (TLS)-ERG, an activated form of ERG found in human leukemia. Via application of SB mutagenesis to TLS-ERG-induced erythroid transformation, we identified multiple loci as likely collaborators with activation of Erg. Jak2 was identified as a common transposon insertion site in TLS-ERG-induced disease, strongly validating the cooperation between JAK2V617F and transposon insertion at the Erg locus in the JAK2V617F-positive leukemias. Moreover, loci expressing other regulators of signal transduction pathways were conspicuous among the common transposon insertion sites in TLS-ERG-driven leukemia, suggesting that a key mechanism in erythroleukemia may be the collaboration of lesions disturbing erythroid maturation, most notably in genes of the ETS family, with mutations that reduce dependence on exogenous signals.

Cyclopamine and jervine induce COX-2 overexpression in human erythroleukemia cells but only cyclopamine has a pro-apoptotic effect

Erythroleukemia is generally associated with a very poor response and survival to current available therapeutic agents. Cyclooxygenase-2 (COX-2) has been described to play a crucial role in the proliferation and differentiation of leukemia cells, this enzyme seems to play an important role in chemoresistance in different cancer types. Previously, we demonstrated that diosgenin, a plant steroid, induced apoptosis in HEL cells with concomitant COX-2 overexpression. In this study, we investigated the antiproliferative and apoptotic effects of cyclopamine and jervine, two steroidal alkaloids with similar structures, on HEL and TF1a human erythroleukemia cell lines and, for the first time, their effect on COX-2 expression. Cyclopamine, but not jervine, inhibited cell proliferation and induced apoptosis in these cells. Both compounds induced COX-2 overexpression which was responsible for apoptosis resistance. In jervine-treated cells, COX-2 overexpression was NF-κB dependent. Inhibition of NF-κB reduced COX-2 overexpression and induced apoptosis. In addition, cyclopamine induced apoptosis and COX-2 overexpression via PKC activation. Inhibition of the PKC pathway reduced both apoptosis and COX-2 overexpression in both cell lines. Furthermore, we demonstrated that the p38/COX-2 pathway was involved in resistance to cyclopamine-induced apoptosis since p38 inhibition reduced COX-2 overexpression and increased apoptosis in both cell lines.

Acute myeloid leukemia (AML) with erythroid predominance exhibits clinical and molecular characteristics that differ from other types of AML

The clinical importance of erythroid predominance in bone marrow of patients with acute myeloid leukemia (AML) is controversial. These cases represent a heterogeneous group of diseases that historically have been classified into different categories. We studied 313 AML patients and specifically compared the clinical, cytogenetic, and molecular features of cases of AML with erythroid predominance, arbitrarily defined as ≥50% erythroid precursors, to AML cases without erythroid predominance. We also assessed 51 patients with a high-grade myelodysplastic syndrome (MDS), refractory anemia with excess blasts (RAEB). All neoplasms were classified according to the World Health Organization classification. With the exception of therapy-related AML/MDS, the presence of erythroid predominance in variously classified categories of AML was associated with a survival advantage. In addition, AML with erythroid predominance had a lower frequency of cytogenetic abnormalities as well as a lower frequency of mutations involving NPM1, NRAS and FLT3 as compared with AML without erythroid predominance. We conclude that the clinical, cytogenetic, and molecular features of AML with erythroid predominance in the non-therapy-related setting are much closer to those of a high-grade myelodysplastic syndrome than they are to other types of AML.

Downregulation of nucleoporin 88 and 214 induced by oridonin may protect OCIM2 acute erythroleukemia cells from apoptosis through regulation of nucleocytoplasmic transport of NF-κB

Oridonin has been utilized for the treatment of various human diseases due to its anti-inflammatory, antibacterial and antitumor effects. However, the precise mechanisms induced by oridonin in human erythroleukemia are yet to be clarified. The present study aimed to elucidate possible oridonin-induced apoptotic mechanisms in OCIM2 cells, as well as the possible mechanisms whereby OCIM2 cells are relatively resistant to oridonin. Results in the present study showed that oridonin significantly inhibited OCIM2 and OCI-AML3 cell proliferation in a dose- and time-dependent manner, while expressing a much higher IC50 in OCIM2, compared to OCI-AML3. These results also indicated that oridonin induced OCIM2 cell apoptosis, associated with p65 and Bax, while activating caspases-9, -6 and -3. However, p65 was only partly translocated into the nucleus, while most of the p65 was retained in the cytoplasm. Moreover, nucleoporin 214 (Nup214) and nucleoporin 88 (Nup88) were downregulated at the transcriptional and protein levels, subsequent to oridonin treatment. Taken together, these data suggest that oridonin has the potential to induce OCIM2 cell-apoptosis, involving NF-κB activation, whereas the downregulation of Nup88 and Nup214 may protect OCIM2 through the regulation of the nucleocytoplasmic transport of p65.