Targeting epigenetic pathways in acute myeloid leukemia and myelodysplastic syndrome: a systematic review of hypomethylating agents trials

Prognostic significance of persisting DNMT3A, ASXL1, and TET2 mutation burden in acute myeloid leukemia patients with allogeneic hematopoietic stem cell transplantation during complete remission

We retrospectively analyzed 155 AML patients with DAT mutations at diagnosis who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) at complete remission. Of the 155 AML patients with DAT mutations at diagnosis, 59 (38.1%) patients had persisting DAT mutations pretransplantation. Compared to patients with pretransplant DAT transitions, patients with persisting DAT mutation burden were shown to be older (p = 0.004), and fewer patients had TET2 mutations at diagnosis (p = 0.033). Patients with persistent DAT mutation burden had shorter overall survival (OS) (3-year OS: 59.3% vs. 83.0%, p < 0.001) and disease-free survival (DFS) (3-year DFS: 56.1% vs. 83.0%, p < 0.001) with a higher cumulative incidence of relapse (CIR) (24.6% vs. 17.4%, p = 0.002) than those with DAT transitions. Additionally, multivariate analysis confirmed that persisting DAT mutations were an independent adverse factor for relapse, OS, and DFS. Collectively, persisting DAT mutations prior to allo-HSCT at complete remission for AML correlated with negative outcomes.

Hypomethylating agents (HMAs) show benefit in AML rather than in intermediate/high-risk MDS based on genetic mutations in epigenetic modification (EMMs): from a retrospective study

Since HMAs were recommended for treatments in AML and MDS, we wondered whether HMAs could provide similar benefit to AML and intermediate/high-risk MDS under the direction of next-generation sequencing. Here we retrospectively analyzed the prognosis of 176 AML and 128 intermediate/high-risk MDS patients treated with HMAs or non-HMA regimens. For AML, HMAs regimen was related to better CR rate compared with non-HMA regimen in elder cohort, while the situation was the opposite in younger cohort. In consolidation phase, EMM (+) patients could benefit from HMAs regimen. Relapsed AML patients receiving HMAs regimen rather than non-HMA regimen had better post-relapse survival. Multivariate analysis identified HMA regimen as an independent prognostic factor for OS in EMM (+) cohort. For intermediate/high-risk MDS patients not undergoing HSCT, however, HMA regimen showed no survival advantage in EMM (+) cohort and was conversely associated with shorter survival in EMM (-) cohort compared with non-HMA regimen. And among those undergoing HSCT, HMA prior to HSCT predicted poor prognosis compared with upfront HSCT regardless of the existence of EMMs. Therefore, HMAs had better therapeutic value in AML rather than in intermediate/high-risk MDS based on EMMs.

Molecular Techniques and Gene Mutations in Myelodysplastic Syndromes

Sequencing technology, particularly next-generation sequencing, has highlighted the importance of gene mutations in myelodysplastic syndromes (MDSs). Mutations affecting DNA methylation, chromatin modification, RNA splicing, cohesin complex, and other pathways are present in most MDS cases and often have prognostic and clinical implications. Updated international diagnostic guidelines as well as the new International Prognostic Scoring System-Molecular incorporate molecular data into the diagnosis and prognostication of MDS. With whole-genome sequencing predicted to become the future standard of genetic evaluation, it is likely that MDS diagnosis and management will become increasingly personalized based on an individual's clinical and genomic profile.

Progress of research on PD-1/PD-L1 in leukemia

Leukemia cells prevent immune system from clearing tumor cells by inducing the immunosuppression of the bone marrow (BM) microenvironment. In recent years, further understanding of the BM microenvironment and immune landscape of leukemia has resulted in the introduction of several immunotherapies, including checkpoint inhibitors, T-cell engager, antibody drug conjugates, and cellular therapies in clinical trials. Among them, the programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) axis is a significant checkpoint for controlling immune responses, the PD-1 receptor on tumor-infiltrating T cells is bound by PD-L1 on leukemia cells. Consequently, the activation of tumor reactive T cells is inhibited and their apoptosis is promoted, preventing the rejection of the tumor by immune system and thus resulting in the occurrence of immune tolerance. The PD-1/PD-L1 axis serves as a significant mechanism by which tumor cells evade immune surveillance, and PD-1/PD-L1 checkpoint inhibitors have been approved for the treatment of lymphomas and varieties of solid tumors. However, the development of drugs targeting PD-1/PD-L1 in leukemia remains in the clinical-trial stage. In this review, we tally up the basic research and clinical trials on PD-1/PD-L1 inhibitors in leukemia, as well as discuss the relevant toxicity and impacts of PD-1/PD-L1 on other immunotherapies such as hematopoietic stem cell transplantation, bi-specific T-cell engager, chimeric antigen receptor T-cell immunotherapy.

Emerging roles of m6A RNA modification in cancer therapeutic resistance

Marvelous advancements have been made in cancer therapies to improve clinical outcomes over the years. However, therapeutic resistance has always been a major difficulty in cancer therapy, with extremely complicated mechanisms remain elusive. N6-methyladenosine (m6A) RNA modification, a hotspot in epigenetics, has gained growing attention as a potential determinant of therapeutic resistance. As the most prevalent RNA modification, m6A is involved in every links of RNA metabolism, including RNA splicing, nuclear export, translation and stability. Three kinds of regulators, "writer" (methyltransferase), "eraser" (demethylase) and "reader" (m6A binding proteins), together orchestrate the dynamic and reversible process of m6A modification. Herein, we primarily reviewed the regulatory mechanisms of m6A in therapeutic resistance, including chemotherapy, targeted therapy, radiotherapy and immunotherapy. Then we discussed the clinical potential of m6A modification to overcome resistance and optimize cancer therapy. Additionally, we proposed existing problems in current research and prospects for future research.

Mapping of DNA methylation-sensitive cellular processes in gingival and periodontal ligament fibroblasts in the context of periodontal tissue homeostasis

Interactions between gingival fibroblasts (GFs) and oral pathogens contribute to the chronicity of inflammation in periodontitis. Epigenetic changes in DNA methylation are involved in periodontitis pathogenesis, and recent studies indicate that DNA methyltransferase (DNMT) inhibitors may protect against epithelial barrier disruption and bone resorption. To assess the impact of DNMT inhibition on GFs, cells were cultured with decitabine (5-aza-2'-deoxycytidine, DAC) for 12 days to induce DNA hypomethylation. We observed several potentially detrimental effects of DAC on GF biological functions. First, extended treatment with DAC reduced GF proliferation and induced necrotic cell death. Second, DAC amplified Porphyromonas gingivalis- and cytokine-induced expression and secretion of the chemokine CCL20 and several matrix metalloproteinases (MMPs), including MMP1, MMP9, and MMP13. Similar pro-inflammatory effects of DAC were observed in periodontal ligament fibroblasts. Third, DAC upregulated intercellular adhesion molecule-1 (ICAM-1), which was associated with increased P. gingivalis adherence to GFs and may contribute to bacterial dissemination. Finally, analysis of DAC-induced genes identified by RNA sequencing revealed increased expression of CCL20, CCL5, CCL8, CCL13, TNF, IL1A, IL18, IL33, and CSF3, and showed that the most affected processes were related to immune and inflammatory responses. In contrast, the genes downregulated by DAC were associated with extracellular matrix and collagen fibril organization. Our observations demonstrate that studies of DNMT inhibitors provide important insights into the role of DNA methylation in cells involved in periodontitis pathogenesis. However, the therapeutic potential of hypomethylating agents in periodontal disease may be limited due to their cytotoxic effects on fibroblast populations and stimulation of pro-inflammatory pathways.

SPRTN and TDP1/TDP2 Independently Suppress 5-Aza-2'-deoxycytidine-Induced Genomic Instability in Human TK6 Cell Line

DNA-protein cross-links (DPCs) are generated by internal factors such as cellular aldehydes that are generated during normal metabolism and external factors such as environmental mutagens. A nucleoside analog, 5-aza-2'-deoxycytidine (5-azadC), is randomly incorporated into the genome during DNA replication and binds DNA methyltransferase 1 (DNMT1) covalently to form DNMT1-DPCs without inducing DNA strand breaks. Despite the recent progress in understanding the mechanisms of DPCs repair, how DNMT1-DPCs are repaired is unclear. The metalloprotease SPRTN has been considered as the primary enzyme to degrade protein components of DPCs to initiate the repair of DPCs. In this study, we showed that SPRTN-deficient (SPRTN^-/-) human TK6 cells displayed high sensitivity to 5-azadC, and the removal of 5-azadC-induced DNMT1-DPCs was significantly slower in SPRTN^-/- cells than that in wild-type cells. We also showed that the ubiquitination-dependent proteasomal degradation, which was independent of the SPRTN-mediated processing, was also involved in the repair of DNMT1-DPCs. Unexpectedly, we found that cells that are double deficient in tyrosyl DNA phosphodiesterase 1 and 2 (TDP1^-/-TDP2^-/-) were also sensitive to 5-azadC, although the removal of 5-azadC-induced DNMT1-DPCs was not compromised significantly. Furthermore, the 5-azadC treatment induced a marked accumulation of chromosomal breaks in SPRTN^-/- as well as TDP1^-/-TDP2^-/- cells compared to wild-type cells, strongly suggesting that the 5-azadC-induced cell death was attributed to chromosomal DNMT1-DPCs. We conclude that SPRTN protects cells from 5-azadC-induced DNMT1-DPCs, and SPRTN may play a direct proteolytic role against DNMT1-DPCs and TDP1/TDP2 also contributes to suppress genome instability caused by 5-azadC in TK6 cells.

The future of research in hematology: Integration of conventional studies with real-world data and artificial intelligence

Most national health-care systems approve new drugs based on data of safety and efficacy from large randomized clinical trials (RCTs). Strict selection biases and study-entry criteria of subjects included in RCTs often do not reflect those of the population where a therapy is intended to be used. Compliance to treatment in RCTs also differs considerably from real world settings and the relatively small size of most RCTs make them unlikely to detect rare but important safety signals. These and other considerations may explain the gap between evidence generated in RCTs and translating conclusions to health-care policies in the real world. Real-world evidence (RWE) derived from real-world data (RWD) is receiving increasing attention from scientists, clinicians, and health-care policy decision-makers - especially when it is processed by artificial intelligence (AI). We describe the potential of using RWD and AI in Hematology to support research and health-care decisions.

Use of Azacitidine or Decitabine for the Up-Front Setting in Acute Myeloid Leukaemia: A Systematic Review and Meta-Analysis

Simple Summary

Azacitidine and decitabine have been increasingly used for the treatment of acute myeloid leukaemia in older patients. The choice between azacitidine and decitabine depends mostly on the experience and preference of the attending physician, since they have not been compared directly in a randomised clinical trial. In this study, we identified the best treatment regimen for each drug and compare the efficacy of decitabine and azacitidine monotherapy in newly diagnosed acute myeloid leukaemia. We found no significant differences regarding 1-year mortality and overall survival for azacitidine and decitabine (roughly 9 months). Moreover, there were no significant differences in the efficacy of 5-day versus 10-day schedules of decitabine. However, patients treated with the shortened 5-day azacitidine scheme showed worsened outcomes compared to the standard 7-day regimen. Hopefully, our results might be helpful for the design of azacitidine/decitabine-based combination schedules to be tested in future trials.

Abstract

Irruption of decitabine and azacitidine has led to profound changes in the upfront management of older acute myeloid leukaemia (AML). However, they have not been directly compared in a randomised clinical trial. In addition, there are no studies comparing the optimal treatment schedule of each drug in AML. A systematic review and meta-analysis on the efficacy of decitabine and azacitidine monotherapy in newly diagnosed AML was conducted. Randomised controlled trials and retrospective studies were included. A total of 2743 patients from 23 cohorts were analysed (10 cohorts of azacitidine and 13 of decitabine). Similar response rates were observed for azacitidine (38%, 95% CI: 30–47%) compared to decitabine (40%, 95% CI: 32–48%) (p = 0.825). Overall survival (OS) between azacitidine (10.04 months, 95% CI: 8.36–11.72) and decitabine (8.79 months, 95% CI: 7.62–9.96) was also similar (p = 0.386). Patients treated with azacitidine showed a lower median OS when azacitidine was administered for 5 days (6.28 months, 95% CI: 4.23–8.32) compared to the standard 7-day schedule (10.83 months, 95% CI: 9.07–12.59, p = 0.002). Among patients treated with decitabine, response rates and OS were not significantly different between 5-day and 10-day decitabine regimens. Despite heterogeneity between studies, we found no differences in response rates and OS in AML patients treated with azacitidine or decitabine.

Bone marrow ribonucleotide reductase mRNA levels and methylation status as prognostic factors in patients with myelodysplastic syndrome treated with 5-Azacytidine

Ribonucleotide Reductase (RNR) is a two-subunit (RRM1, RRM2) enzyme, responsible for the conversion of ribonucleotides to deoxyribonucleotides required for DNA replication. To evaluate RNR as a biomarker of response to 5-azacytidine, we measured RNR mRNA levels by a quantitative real-time PCR in bone marrow samples of 98 patients with myelodysplastic syndrome (MDS) treated with 5-azacytidine with parallel quantification of the gene promoter's methylation. Patients with low RRM1 levels had a high RRM1 methylation status (p = 0.005) and a better response to treatment with 5-azacytidine (p = 0.019). A next-generation sequencing for genes of interest in MDS was also carried out in a subset of 61 samples. Splicing factor mutations were correlated with lower RRM1 mRNA levels (p = 0.044). Our results suggest that the expression of RNR is correlated with clinical outcomes, thus its expression could be used as a prognostic factor for response to 5-azacytidine and a possible therapeutic target in MDS.

Exposure to hypomethylating 5-aza-2'-deoxycytidine (decitabine) causes rapid, severe DNA damage, telomere elongation and mitotic dysfunction in human WIL2-NS cells

BACKGROUND

5-aza-2'-deoxycytidine (5azadC, decitabine) is a DNA hypomethylating agent used in the treatment of myelodysplastic syndromes. Due to cytotoxic side effects dose optimization is essential. The aim of this study was to define and quantify the effects of 5azadC on biomarkers of chromosomal stability, and telomere length, in human lymphoblastoid cell line, WIL2-NS, at clinically relevant dosages.

METHODS

Human WIL2-NS cells were maintained in complete medium containing 0, 0.2 or 1.0 μM 5azadC for four days, and analysed daily for telomere length (flow cytometry), chromosomal stability (cytokinesis-block micronucleus cytome (CBMN-cyt) assay), and global methylation (%5me-C).

RESULTS

DNA methylation decreased significantly in 1.0 μM 5azadC, relative to control (p < 0.0001). Exposure to 1.0 μM 5azadC resulted in 1.7-fold increase in telomere length (p < 0.0001), in parallel with rapid increase in biomarkers of DNA damage; (micronuclei (MN, 6-fold increase), nucleoplasmic bridges (NPB, a 12-fold increase), and nuclear buds (NBud, a 13-fold increase) (all p < 0.0001). Fused nuclei (FUS), indicative of mitotic dysfunction, showed a 5- and 13-fold increase in the 0.2 μM and 1.0 μM conditions, respectively (p = 0.001) after 4 days.

CONCLUSIONS

These data show that (i) clinically relevant concentrations of 5azadC are highly genotoxic; (ii) hypomethylation was associated with increased TL and DNA damage; and (iii) longer TL was associated with chromosomal instability. These findings suggest that lower doses of 5azdC may be effective as a hypomethylating agent, while potentially reducing DNA damage and risk for secondary disease.

TFEB links MYC signaling to epigenetic control of myeloid differentiation and acute myeloid leukemia

MYC oncoproteins regulate transcription of genes directing cell proliferation, metabolism and tumorigenesis. A variety of alterations drive MYC expression in acute myeloid leukemia (AML) and enforced MYC expression in hematopoietic progenitors is sufficient to induce AML. Here we report that AML and myeloid progenitor cell growth and survival rely on MYC-directed suppression of Transcription Factor EB (TFEB), a master regulator of the autophagy-lysosome pathway. Notably, although originally identified as an oncogene, TFEB functions as a tumor suppressor in AML, where it provokes AML cell differentiation and death. These responses reflect TFEB control of myeloid epigenetic programs, by inducing expression of isocitrate dehydrogenase-1 (IDH1) and IDH2, resulting in global hydroxylation of 5-methycytosine. Finally, activating the TFEB-IDH1/IDH2-TET2 axis is revealed as a targetable vulnerability in AML. Thus, epigenetic control by a MYC-TFEB circuit dictates myeloid cell fate and is essential for maintenance of AML.

TBC1D16 predicts chemosensitivity and prognosis in adult acute myeloid leukemia (AML) patients

Acute myeloid leukemia (AML) is a hematopoietic disease with poor survival. Chemotherapy resistance is one of the determinant factors influencing AML prognosis. To identify genes possibly affecting the drug responses in AML, the Illumina Infinium MethylationEPIC (850K) was used to screen for differential DNA methylation loci between patients achieved complete remission (CR) or not (non-CR) after induction therapy in 37 AML patients. Then, 32 differentially methylated sites (DMS) were selected for replication in another 86 AML patients by next-generation sequencing. Nine sites including cg03988660, cg16804603, cg18166936, cg11308319, cg09095403, cg18493214, cg01443536, cg16030878 and cg10143426 were replicated. Analysis of the Gene Expression Omnibus (GEO) database showed that mRNA expression of TBC1D16 and HDAC4 was associated with AML prognosis. Methylation level of the cg16030878 in TBC1D16 3'-UTR correlated positively with TBC1D16 mRNA expression in samples both in the TCGA database and clinically collected in the study. Both higher cg16030878 methylation and higher TBC1D16 mRNA expression were associated with increased risk of non-CR and worse overall survival (OS) in AML patients. In AML cells, knockdown of TBC1D16 decreased cell proliferation and ERK phosphorylation levels, as well as increased sensitivity to mitoxantrone and decitabine indicated by IC₅₀. In patients with combined use of decitabine, those patients with CR showed significantly lower TBC1D16 mRNA expression. On the contrary, knockdown of TBC1D16 resulted in decreased sensitivity to cytarabine in U937 cells. Our findings implicated that TBC1D16 is a potential predictor for chemosensitivity and prognosis in adult AML patients.

Multi Cytogenetic Changes in a Patient as Co-Existing MDS and CLL Progresses

Background

Chronic lymphocytic leukemia (CLL) and myelodysplastic syndrome (MDS) existing simultaneously in untreated patients is extremely rare. There have only been nine cases of untreated CLL concurrent with or followed by the development of MDS. Of all nine cases, four patients exhibited results of cytogenetic phonotypes all showing more than one abnormal chromosome karyotype. It is unknown whether or not these abnormal chromosome karyotypes change during the development of the disease. Meanwhile, the optimal treatment for the concurrence of CLL with MDS has yet to be identified.

Case Presentation

A 69-year-old Chinese man diagnosed with co-existing CLL with MDS was observed from diagnosis, treatment, relapse to death during an admission period of a total of 158 days. Since being diagnosed with CLL and MDS, he was treated by decitabine and his condition went into remission for three months. Four laboratory tests showed an abnormal chromosome cytogenetic karyotype successively changed during the progression of the disease.

Conclusion

It is the first time the abnormal chromosome karyotype variation significantly associated with the change of the illness was discovered. In the relapse and deterioration stages of the disease, there was t(9;22)(q24; q11.2); add(11)(p15) and other chromosome translocation. Repeated occurrence of TET2 mutation is special at this stage of the disease. Furthermore, decitabine could be beneficial for the treatment of the disease.

Venetoclax + hypomethylating agents combined with dose-adjusted HAG for relapsed/refractory acute myeloid leukemia: Two case reports

RATIONALE

Some acute myeloid leukemia (AML) patients are unresponsive to treatment or have remission followed by worsening of disease (known as relapsed/refractory AML [R/RAML]) after standardized treatment. The CAG/HAG regimen is not often used clinically because heterogenous patient responses, resistance, and hematopoietic bone marrow dysfunction have been reported with its use. We present 2 cases of R/RAML treated with a new combined therapy (venetoclax+ hypomethylating agents [HMAs]) in which the HAG dose was adjusted and effective in the first course of treatment.

PATIENT CHARACTERISTICS

Case 1 involved a 23-year-old man who had suffered from AML for >4 years, and his FLT3 mutation status was positive at the initial diagnosis. After the first course of treatment with the standard-dose "Da" plan, the patient experienced complete remission. During the subsequent courses of treatment, the patient experienced 6 recurrences and was treated with the "ID Ara-C + MIT + sidaaniline" and "CAG + sidaaniline" regimens. However, the disease did not respond. Case 2 involved a 26-year-old man who received chemotherapy with the "Da," "ID Ara-C," "decitabine + half-dose CAG," and "HAE" regimens. In this patients, remission could not be achieved. Reintroduction of the "ia" scheme also failed after treatment in our hospital.

DIAGNOSIS

Two patients were diagnosed with R/RAML.

INTERVENTIONS

The patient in case 2 received chemotherapy interventions, whereas the patient in case 1 refused to receive medical services at our hospital.

OUTCOMES

The patient in case 1 was discharged after complete response treatment due to economic reasons and relapsed 2 months later. The patient ultimately died of infection and heart failure. The patient in case 2 is receiving a second cycle of chemotherapy.

LESSONS

We recommend the "venetoclax + HMAs combined with dose-adjusted CAH/HAG" regimen as an effective treatment for adult R/RAML.

Effect of rhG-CSF Combined With Decitabine Prophylaxis on Relapse of Patients With High-Risk MRD-Negative AML After HSCT: An Open-Label, Multicenter, Randomized Controlled Trial

Relapse is a major cause of treatment failure after allogeneic hematopoietic stem-cell transplantation (allo-HSCT) for high-risk acute myeloid leukemia (HR-AML). The aim of this study was to explore the effect of recombinant human granulocyte colony-stimulating factor (rhG-CSF) combined with minimal-dose decitabine (Dec) on the prevention of HR-AML relapse after allo-HSCT.

Medulloblastoma epigenetics and the path to clinical innovation

INTRODUCTION

In the last decade, a number of genomic and pharmacological studies have demonstrated the importance of epigenetic dysregulation in medulloblastoma initiation and progression. High throughput approaches including gene expression array, next-generation sequencing (NGS), and methylation profiling have now clearly identified at least four molecular subgroups within medulloblastoma, each with distinct clinical and prognostic characteristics. These studies have clearly shown that despite the overall paucity of mutations, clinically relevant events do occur within the cellular epigenetic machinery. Thus, this review aims to provide an overview of our current understanding of the spectrum of epi-oncogenetic perturbations in medulloblastoma.

METHODS

Comprehensive review of epigenetic profiles of different subgroups of medulloblastoma in the context of molecular features. Epigenetic regulation is mediated mainly by DNA methylation, histone modifications and microRNAs (miRNA). Importantly, epigenetic mis-events are reversible and have immense therapeutic potential.

CONCLUSION

The widespread epigenetic alterations present in these tumors has generated intense interest in their use as therapeutic targets. We provide an assessment of the progress that has been made towards the development of molecular subtypes-targeted therapies and the current status of clinical trials that have leveraged these recent advances.

AML with Myelodysplasia-Related Changes: Development, Challenges, and Treatment Advances

Acute myeloid leukemia (AML) with myelodysplasia-related changes (AML-MRC) is a distinct biologic subtype of AML that represents 25-34% of all AML diagnoses and associates with especially inferior outcomes compared to non-MRC AML. Typically, patients with AML-MRC experience low remission rates following intensive chemotherapy and a median overall survival of merely 9-12 months. In light of these discouraging outcomes, it has become evident that more effective therapies are needed for patients with AML-MRC. Liposomal daunorubicin-cytarabine (CPX-351) was approved in 2017 for adults with newly diagnosed AML-MRC and those with therapy-related AML (t-AML), and remains the only therapy specifically approved for this patient population. Other studies have also demonstrated the efficacy of the hypomethylating agent (HMA) azacitidine as upfront therapy for AML-MRC patients, which, to date, is the most common treatment employed for patients unable to tolerate the more intensive CPX-351. HMAs and venetoclax combinations have also been evaluated, but additional studies utilizing these agents in this specific subgroup are needed before conclusions regarding their role in the therapeutic armamentarium of AML-MRC patients can be reached. Currently, many studies are ongoing in attempts to further improve outcomes in this historically ill-fated patient group.

Targeting FTO Suppresses Cancer Stem Cell Maintenance and Immune Evasion

Fat mass and obesity-associated protein (FTO), an RNA N⁶-methyladenosine (m⁶A) demethylase, plays oncogenic roles in various cancers, presenting an opportunity for the development of effective targeted therapeutics. Here, we report two potent small-molecule FTO inhibitors that exhibit strong anti-tumor effects in multiple types of cancers. We show that genetic depletion and pharmacological inhibition of FTO dramatically attenuate leukemia stem/initiating cell self-renewal and reprogram immune response by suppressing expression of immune checkpoint genes, especially LILRB4. FTO inhibition sensitizes leukemia cells to T cell cytotoxicity and overcomes hypomethylating agent-induced immune evasion. Our study demonstrates that FTO plays critical roles in cancer stem cell self-renewal and immune evasion and highlights the broad potential of targeting FTO for cancer therapy.

Caffeic acid and chlorogenic acid cytotoxicity, genotoxicity and impact on global DNA methylation in human leukemic cell lines

Dietary phenolic compounds such as caffeic and chlorogenic acid exert an antiproliferative effect and modulate the gene-specific DNA methylation status in human breast tumor cells, but it remains unclear whether they interfere with global DNA methylation in human leukemia cells. We examined whether caffeic and chlorogenic acid (1-250 µM) exert antitumor action in human promyelocytic leukemia cells (HL-60) and human acute T-cell leukemia cells (Jurkat). Caffeic and chlorogenic acid did not reduce cell viability in the two cell lines, as assessed using the neutral red uptake and MTT assays. These phenolic acids (1-100 μM) neither induced DNA damage (comet assay) nor increased the micronuclei frequency (micronucleus assay) in HL-60 and Jurkat cells, indicating that they were not genotoxic or mutagenic. Analysis of global DNA methylation levels using a 5-mC DNA ELISA kit revealed that chlorogenic acid at a non-cytotoxic concentration (100 μM) induced global DNA hypomethylation in Jurkat cells, but not in HL-60 cells, suggesting that it exerts a cell-specific effect. Caffeic acid did not change global DNA methylation. As other phenolic compounds, chlorogenic acid probably modulates DNA methylation by targeting DNA methyltransferases. The hypomethylating action of chlorogenic acid can be beneficial against hematological malignances whose pathogenic processes involve impairment of DNA methylation.

Comparison of mutational profiles and clinical outcomes in patients with acute myeloid leukemia with mutated RUNX1 versus acute myeloid leukemia with myelodysplasia-related changes with mutated RUNX1

Studies comparing the prognostic role of RUNX1 mutations (RUNX1^mut) in acute myeloid leukemia (AML) and acute myeloid leukemia-with myelodysplasia-related changes (AML-MRC) are limited. Our study examines the genetic profile of 118 RUNX1^mut AML patients including 57 AML with RUNX1^mut and 61 AML-MRC with RUNX1^mut and 100 AML, NOS patients with wild type RUNX1 (RUNX1^wt). Results revealed that AML-MRC patients with RUNX1^mut had shorter median overall survival (OS) (11 ± 3.3 months) when compared to AML with RUNX1^mut (19 ± 7.1 months) and AML, NOS with RUNX1^wt (not reached) (p = .001). The most common concurrent mutations observed in AML-MRC with RUNX1^mut patients were DNMT3A, SRSF2, ASXL1, and IDH2 while in AML with RUNX1^mut patients were ASXL1, SRSF2, TET2, IDH2, and DNMT3A. ASXL1 and TET2 mutations appeared to adversely affect OS in AML-MRC, but not in AML with RUNX1^mut. Concurrent RUNX1/DNMT3A mutations, in contrast had negative impact on OS in AML with RUNX1^mut, but not in AML-MRC with RUNX1^mut.

Decitabine and all-trans retinoic acid synergistically exhibit cytotoxicity against elderly AML patients via miR-34a/MYCN axis

This study aimed to investigate the efficacy and mechanism of decitabine (DAC) and all-trans retinoic acid (ATRA) in elderly acute myeloid leukemia (AML) patients and cultured cells. Our clinical trial enrolled 36 elderly patients who were judged ineligible for conventional chemotherapy, receiving DAC and ATRA regimen (DAC 20 mg/m² days 1-5; ATRA 20 mg/m² days 4-28 in the first cycle and days 1-28 in the subsequent cycle). Treated with a median of 3 cycles (range 1-6), 44.4 % of patients achieved complete remission (CR), 11.1 % achieved CR with incomplete peripheral count recovery (CRi) and 13.9 % achieved partial remission (PR). The median overall survival (OS) was 12.1 months; the 1-year and 2-year OS rates were 49.6 % and 17.2 %. In addition, our in vitro studies indicated that the antineoplastic activities of DAC and ATRA mutually reinforced, which induced growth inhibition, cell cycle arrest and apoptosis of AML cells. Meanwhile, we found DAC and ATRA inhibited DNMT1, activated miR-34a via promoter hypomethylation, down-regulated its target MYCN and thus exerted a synergistic antineoplastic effect. In conclusion, DAC plus ATRA regimen might be effective and well-tolerated for elderly patients partially through modulating miR-34a/MYCN axis.

DNA Methylation of Enhancer Elements in Myeloid Neoplasms: Think Outside the Promoters?

Gene regulation through DNA methylation is a well described phenomenon that has a prominent role in physiological and pathological cell-states. This epigenetic modification is usually grouped in regions denominated CpG islands, which frequently co-localize with gene promoters, silencing the transcription of those genes. Recent genome-wide DNA methylation studies have challenged this paradigm, demonstrating that DNA methylation of regulatory regions outside promoters is able to influence cell-type specific gene expression programs under physiologic or pathologic conditions. Coupling genome-wide DNA methylation assays with histone mark annotation has allowed for the identification of specific epigenomic changes that affect enhancer regulatory regions, revealing an additional layer of complexity to the epigenetic regulation of gene expression. In this review, we summarize the novel evidence for the molecular and biological regulation of DNA methylation in enhancer regions and the dynamism of these changes contributing to the fine-tuning of gene expression. We also analyze the contribution of enhancer DNA methylation on the expression of relevant genes in acute myeloid leukemia and chronic myeloproliferative neoplasms. The characterization of the aberrant enhancer DNA methylation provides not only a novel pathogenic mechanism for different tumors but also highlights novel potential therapeutic targets for myeloid derived neoplasms.

Aberrant DNA Methylation in Acute Myeloid Leukemia and Its Clinical Implications

Acute myeloid leukemia (AML) is a heterogeneous disease that is characterized by distinct cytogenetic or genetic abnormalities. Recent discoveries in cancer epigenetics demonstrated a critical role of epigenetic dysregulation in AML pathogenesis. Unlike genetic alterations, the reversible nature of epigenetic modifications is therapeutically attractive in cancer therapy. DNA methylation is an epigenetic modification that regulates gene expression and plays a pivotal role in mammalian development including hematopoiesis. DNA methyltransferases (DNMTs) and Ten-eleven-translocation (TET) dioxygenases are responsible for the dynamics of DNA methylation. Genetic alterations of DNMTs or TETs disrupt normal hematopoiesis and subsequently result in hematological malignancies. Emerging evidence reveals that the dysregulation of DNA methylation is a key event for AML initiation and progression. Importantly, aberrant DNA methylation is regarded as a hallmark of AML, which is heralded as a powerful epigenetic marker in early diagnosis, prognostic prediction, and therapeutic decision-making. In this review, we summarize the current knowledge of DNA methylation in normal hematopoiesis and AML pathogenesis. We also discuss the clinical implications of DNA methylation and the current therapeutic strategies of targeting DNA methylation in AML therapy.

A favorable inductive remission rate for decitabine combined with chemotherapy as a first course in <60-year-old acute myeloid leukemia patients with myelodysplasia syndrome features

In acute myeloid leukemia (AML), myelodysplasia-related changes contribute to a poor prognosis. This retrospective, propensity score-matched study analyzed 108 newly diagnosed AML patients with features of myelodysplasia syndrome (MDS) (aged 14-60 years) from 2014 to 2018, who received either idarubicin and cytarabine (IA) or decitabine, idarubicin and cytarabine (DAC+IA), and compared efficacy and toxicity between the two regimens. After propensity score matching, there were 54 patients in each group. The rate of complete remission (CR) was higher in the DAC+IA group than in the IA group (85.2% vs 68.5%, P = .040) after the first course, and toxicities were comparable in both groups. Multivariate analysis indicated that the combination with DAC was independent factor for CR rate after the first induction therapy (OR = 2.978, 95% CI:1.090-8.137, P = .033). Subgroup analysis showed a CR advantage for DAC+IA (vs IA) for patients of intermediate-high risk status according to National Comprehensive Cancer Network prognostic stratification. In conclusion, DAC+IA is therefore offered as a new induction choice for newly diagnosed AML patients with features of MDS, aged <60 years old, especially in intermediate-high risk status.

Recent Advances in Use of Topoisomerase Inhibitors in Combination Cancer Therapy

Inhibitors targeting human topoisomerase I and topoisomerase II alpha have provided a useful chemotherapy option for the treatment of many patients suffering from a variety of cancers. While the treatment can be effective in many patient cases, use of these human topoisomerase inhibitors is limited by side-effects that can be severe. A strategy of employing the topoisomerase inhibitors in combination with other treatments can potentially sensitize the cancer to increase the therapeutic efficacy and reduce resistance or adverse side effects. The combination strategies reviewed here include inhibitors of DNA repair, epigenetic modifications, signaling modulators and immunotherapy. The ongoing investigations on cellular response to topoisomerase inhibitors and newly initiated clinical trials may lead to adoption of novel cancer therapy regimens that can effectively stop the proliferation of cancer cells while limiting the development of resistance.

LINC00162 confers sensitivity to 5-Aza-2'-deoxycytidine via modulation of an RNA splicing protein, HNRNPH1

DNA demethylation therapy is now expanding from hematological tumors to solid tumors. To exploit its maximum efficacy, long-term treatment is needed, and stratification of sensitive patients is critically important. Here, we identified a long non-coding RNA, LINC00162, as highly and frequently expressed in gastric cancer cell lines sensitive to 5-aza-2'-deoxycytidine (5-aza-dC). Knockdown of LINC00162 decreased the sensitivity while its overexpression increased the sensitivity. In vivo experiments also showed that LINC00162 overexpression increased the sensitivity. LINC00162 enhanced cell cycle arrest and apoptosis induced by 5-aza-dC, but did not affect its DNA demethylation effect. Mechanistically, LINC00162 interacted with an RNA splicing protein, HNRNPH1, and decreased splicing of an anti-apoptotic splicing variant, BCL-XL. LINC00162 may have translational value to predict patients who will respond to 5-aza-dC.

Aplastic Anemia & MDS International Foundation (AA&MDSIF): Bone Marrow Failure Disease Scientific Symposium 2018

The bone marrow failure (BMF) syndromes are a group of rare disorders characterized by ineffective hematopoiesis resulting from deficiencies in the hematopoietic stem cell compartment. Although these diseases are typically acquired, some forms (e.g., Fanconi anemia, dyskeratosis congenita, Diamond Blackfan anemia, and Shwachman Diamond syndrome) are inherited. Patients with BMF syndromes can develop peripheral blood cytopenias and pancytopenia, and their disease can ultimately progress to acute myelogenous leukemia (AML). Research around the world is shedding light on the biology of the BMF syndromes, their clinical effects, and novel treatments. The Aplastic Anemia and MDS International Foundation (AAMDSIF) is an independent nonprofit organization whose mission is to help patients and family members cope with BMF syndromes. This report summarizes presentations on the latest scientific discoveries in BMF syndromes from the Sixth International Bone Marrow Failure Disease Scientific Symposium sponsored by AAMDSIF on March 22-23, 2018, in Rockville, Maryland.

Cardiovascular Programming During and After Diabetic Pregnancy: Role of Placental Dysfunction and IUGR

Intrauterine growth restriction (IUGR) is a condition whereby a fetus is unable to achieve its genetically determined potential size. IUGR is a global health challenge due to high mortality and morbidity amongst affected neonates. It is a multifactorial condition caused by maternal, fetal, placental, and genetic confounders. Babies born of diabetic pregnancies are usually large for gestational age but under certain conditions whereby prolonged uncontrolled hyperglycemia leads to placental dysfunction, the outcome of the pregnancy is an intrauterine growth restricted fetus with clinical features of malnutrition. Placental dysfunction leads to undernutrition and hypoxia, which triggers gene modification in the developing fetus due to fetal adaptation to adverse utero environmental conditions. Thus, in utero gene modification results in future cardiovascular programming in postnatal and adult life. Ongoing research aims to broaden our understanding of the molecular mechanisms and pathological pathways involved in fetal programming due to IUGR. There is a need for the development of effective preventive and therapeutic strategies for the management of growth-restricted infants. Information on the mechanisms involved with in utero epigenetic modification leading to development of cardiovascular disease in adult life will increase our understanding and allow the identification of susceptible individuals as well as the design of targeted prevention strategies. This article aims to systematically review the latest molecular mechanisms involved in the pathogenesis of IUGR in cardiovascular programming. Animal models of IUGR that used nutrient restriction and hypoxia to mimic the clinical conditions in humans of reduced flow of nutrients and oxygen to the fetus will be discussed in terms of cardiac remodeling and epigenetic programming of cardiovascular disease. Experimental evidence of long-term fetal programming due to IUGR will also be included.

Epigenetic treatment-mediated modulation of PD-L1 predicts potential therapy resistance over response markers in myeloid malignancies: A molecular mechanism involving effectors of PD-L1 reverse signaling

Recent evidence suggests an association exists between resistance to epigenetic therapy (EGT) and the expression of programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) in myeloid malignancies. Biomarkers are required to predict resistance to EGT in myeloid malignancies, which together with the delineation of associated molecular mechanisms, may provide additional understanding for novel treatment strategies when investigating resistance to EGT. The present study aimed to investigate the in vivo effects of EGT on the expression of PD-1, PD-L1 and orphan nuclear receptor NUR77 with clinical responses in patients with myeloid malignancies. In addition, in vitro and in vivo characterization of the effects of EGT on the expression of NF-κB and Bcl-xL, potential downstream targets of PD-L1 reverse signaling, were evaluated to determine components of the molecular mechanism responsible for these effects. The in vivo effects of EGT on the expression of PD-1, PD-L1 and a previously identified molecular marker of response to EGT, NUR77 was characterized in peripheral blood mononuclear cells (PBMC) from patients with myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) treated with either azacytidine (Aza) alone or a combination of Aza and the histone deacetylase inhibitor (HDACi) LBH-589 during the first cycle of therapy. The correlation of clinical responses to treatment with EGT with the expression of PD-1, PD-L1 and NUR77 demonstrated that the induction of PD-L1 mRNA levels was associated with resistance to EGT despite the concurrent augmentation of NUR77 expression. The characterization of potential downstream effector molecules of reverse PD-L1 signaling identified EGT-mediated induction of Bcl-xL and NF-κB mRNA expression in vitro and in vivo, suggesting a potential anti-apoptotic molecular mechanism was responsible for PD-L1-mediated resistance to EGT. Taken together, these observations suggest that enhanced PD-L1 expression may confer resistance to EGT over known EGT response markers in myeloid malignancies, and provides a potential molecular mechanism involving the modulation of effectors of PD-L1 reverse signaling, which may in-part, be responsible for these effects.

Comparison of DNMT1 inhibitors by methylome profiling identifies unique signature of 5-aza-2'deoxycytidine

AIM

5-aza-2'deoxycytidine (Aza) is used to treat myelodysplastic syndrome and is in trials for other cancers. It acts chiefly as a hypomethylating agent inhibiting DNMT1. A lack of understanding of off-target effects in normal cells hinders wider usage.

MATERIALS & METHODS

We compared treatment of the same normosomic, nontransformed fibroblast cell line with Aza and SMARTpool siRNA against DNMT1. Methylation and transcription were assayed using Illumina 450k and HT12 arrays.

RESULTS

Both Aza and DNMT1 siRNA caused overall hypomethylation, with siRNA more efficient at demethylating gene bodies. Hypomethylation at the promoters of many histones, and hypermethylation at multiple sites genome wide, were unique to Aza treatment.

CONCLUSION

Aza had important unique effects and targets compared with DNMT1 inhibition via siRNA.

Incidence and risk of hematologic toxicities with hypomethylating agents in the treatment of myelodysplastic syndromes and acute myeloid leukopenia: A systematic review and meta-analysis

BACKGROUND

Hypomethylating agents (HMAs) are believed to have reliable efficacy in treating myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). Meanwhile, the adverse events of HMAs have become an increasing concern. There is, however, no systematic meta-analysis available to evaluate overall hematologic toxicities for HMAs. In this meta-analysis, we aim to determine the risk of hematologic toxicities in patients treated with HMAs.

METHODS

Relevant studies were identified from PubMed, Embase, Cochrane Library, and the Clinical Trials. gov databases incepted to February 2018. All phase II and III trials meeting the inclusion criteria included adequate safety data. We calculated the relative risk (RR) of high-grade hematologic toxicities (HTEs) with corresponding 95% CI using Review Manager. The incidences of HTEs were also evaluated by R. Heterogeneity was calculated and reported mainly via I analyses.

RESULTS

A total of 2337 MDS or AML patients from 14 studies were identified in this meta-analysis. The overall incidences of high-grade hematologic toxicities in patients who received HMAs were: 27% of the patients with anemia, 45% with neutropenia, 38% with thrombocytopenia, and 25% with febrile neutropenia, respectively. There was a significantly increased RR of neutropenia and thrombocytopenia using HMAs, in comparison with conventional care regimens (CCR) based on the drug type (decitabine vs azacitidine).

CONCLUSIONS

We conclude that the use of HMAs are associated with an increased risk of neutropenia and thrombocytopenia in MDS or AML patients, and our results also demonstrate that HMAs exposure does not significantly increase the risk of high-grade anemia, leukopenia, or febrile neutropenia compared with CCR.

Epigenetic therapy: azacytidine and decitabine in acute myeloid leukemia

INTRODUCTION

The majority of patients with acute myeloid leukemia (AML) are older and exhibit a poor prognosis even after intensive therapy. Inducing differentiation and apoptosis of leukemic blasts by DNA-hypomethylating agents, like e.g. azacytidine (AZA) and decitabine (DAC), represent well-tolerated alternative treatment approaches. Both agents show convincing response as single agents in AML. However, there is a lack of knowledge regarding molecular mechanisms and predictive biomarkers for these agents. Areas covered: This review will (i) provide an overview of the current knowledge of molecular mechanisms underlying the action of these drugs, (ii) report promising predictive biomarkers, (iii) elude on new combined treatment options, and (iv) discuss novel approaches to improve outcomes. A literature search was performed using PubMed to find recent major publications, which provide biological and clinical research about epigenetic therapy in AML patients. Expert commentary: Numerous studies have demonstrated that HMA therapy with AZA or DAC may lead to significant response rates, even in pre-treated patients. Nevertheless, there is still an unmet need to further improve outcome in elderly AML patients. Therefore, novel treatment combinations are needed and some of them, such as AZA plus venetoclax, already show promising results.

Secreted frizzled-related protein 1 (SFRP1) gene methylation changes in the human lung adenocarcinoma cells treated with L-securinine

Lung cancer remains the leading cause of cancer-related death worldwide. It is important to explore the biomarkers of diagnosis and prognosis in lung cancer. To evaluate the cytotoxicity of L-securinine and the expression and methylation of secreted frizzled-related proteins (SFRPs) genes in the human lung adenocarcinoma cells, cell counting kit-8 (CCK-8) assay was used to assess the proliferation of lung adenocarcinoma cells treated with L-securinine. Quantitative real-time PCR (qRT-PCR) and bisulfite sequencing PCR were used to detect the expression and the DNA methylation of SFRPs genes, respectively. L-securinine inhibited the proliferation of lung adenocarcinoma cells and induced the upregulation of SFRP1 gene expression and the methylation changes at CpG sites in the SFRP1 promoter region. L-securinine was a potential agent in the treatment of lung cancer by upregulation of SFRP1 gene expression and changing the SFRP1 gene methylation.

Epigenetics in Hematological Malignancies

Acute leukemias are hematologic malignancies with aggressive behavior especially in adult population. With the introduction of new gene expression and sequencing technologies there have been advances in the knowledge of the genetic landscape of acute leukemias. A more detailed analysis allows for the identification of additional alterations in epigenetic regulators that have a profound impact in cellular biology without changes in DNA sequence. These epigenetic alterations disturb the physiological balance between gene activation and gene repression and contribute to aberrant gene expression, contributing significantly to the leukemic pathogenesis and maintenance. We review epigenetic changes in acute leukemia in relation to what is known about their mechanism of action, their prognostic role and their potential use as therapeutic targets, with important implications for precision medicine.

Targeting epigenetics for treatment of BRAF mutated metastatic melanoma with decitabine in combination with vemurafenib: A phase lb study

Introduction

Epigenetic modifications play an important role in progression and development of resistance in ^V600EBRAF positive metastatic melanoma. Therefore, we hypothesized that the action of vemurafenib (BRAF inhibitor) can be made more effective by combining with low dose decitabine (a DNA methyltransferase inhibitor). The primary objective of this phase lb study was to determine the dose limiting toxicity and maximum tolerated dose of combination of subcutaneous decitabine with oral vemurafenib in patients with ^V600EBRAF positive metastatic melanoma with or without any prior treatment.

Experimental Design

The study employed 3+3 dose escalation combining subcutaneous decitabine at different doses and schedules (4 cohorts) with the standard oral dose of vemurafenib 960 mg twice daily. Preclinical assessment and further analysis were also performed in A375 melanoma cell line.

Results

Fourteen patients received study treatment. No dose limiting toxicity was encountered and maximum tolerated dose was not reached. Important toxicities included fatigue, increased creatinine, neutropenia, leucopenia, hypophosphatemia, rash and hyperuricemia. Three patients achieved complete response, three had partial response and five had stable disease. Preclinical assessment demonstrated action of the combination which delayed the development of acquired resistance and improved duration of treatment sensitivity.

Conclusions

The combination of oral vemurafenib with subcutaneous decitabine is safe and showed activity in ^V600EBRAF positive metastatic melanoma. Since most responses were seen in cohort 1, which utilized low-dose, long-term decitabine, future studies of this combination treatment should utilize longer duration of decitabine, at the lowest dose of 0.1 mg/kg.

RASSF1A hypermethylation is associated with ASXL1 mutation and indicates an adverse outcome in non-M3 acute myeloid leukemia

Objective

The purpose of this study was to evaluate the frequency of RASSF1A hypermethylation in patients with acute myeloid leukemia (AML), in an attempt to modify the current molecular model for disease prognosis.

Materials and methods

Aberrant RASSF1A promoter methylation levels were assessed in 226 newly diagnosed non-M3 AML patients and 30 apparently healthy controls, by quantitative methylation-specific polymerase chain reaction. Meanwhile, RASSF1A mRNA levels were detected by real-time quantitative polymerase chain reaction. Furthermore, hematological characteristics, cytogenetic abnormalities, and genetic aberrations were assessed. Finally, associations of RASSF1A hypermethylation with clinical outcomes were evaluated.

Results

RASSF1A hypermethylation was observed in 23.0% of patients with non-M3 AML (52/226), but not in controls. Meanwhile, hypermethylation of the RASSF1A promoter was significantly associated with ASXL1 mutation. Furthermore, the log-rank test revealed that RASSF1A hypermethylation indicated decreased relapse-free survival (RFS) and overall survival (OS) in patients with non-M3 AML (P=0.012 and P=0.014, respectively). In multivariate analysis, RASSF1A hypermethylation was an independent prognostic factor for RFS (P=0.040), but not for OS (P=0.060).

Conclusion

Hypermethylation of the RASSF1A promoter is associated with ASXL1 mutation in non-M3 AML patients, likely indicating poor outcome. These findings provide a molecular basis for stratified diagnosis and prognostic evaluation.

Suppression of Transposable Elements in Leukemic Stem Cells

Genomic transposable elements (TEs) comprise nearly half of the human genome. The expression of TEs is considered potentially hazardous, as it can lead to insertional mutagenesis and genomic instability. However, recent studies have revealed that TEs are involved in immune-mediated cell clearance. Hypomethylating agents can increase the expression of TEs in cancer cells, inducing ‘viral mimicry’, causing interferon signalling and cancer cell killing. To investigate the role of TEs in the pathogenesis of acute myeloid leukaemia (AML), we studied TE expression in several cell fractions of AML while tracking its development (pre-leukemic haematopoietic stem cells, leukemic stem cells [LSCs], and leukemic blasts). LSCs, which are resistant to chemotherapy and serve as reservoirs for relapse, showed significant suppression of TEs and interferon pathways. Similarly, high-risk cases of myelodysplastic syndrome (MDS) showed far greater suppression of TEs than low-risk cases. We propose TE suppression as a mechanism for immune escape in AML and MDS. Repression of TEs co-occurred with the upregulation of several genes known to modulate TE expression, such as RNA helicases and autophagy genes. Thus, we have identified potential pathways that can be targeted to activate cancer immunogenicity via TEs in AML and MDS.

Implications of mutational spectrum in myelodysplastic syndromes based on targeted next-generation sequencing

Myelodysplastic syndromes (MDS) are a group of myeloid hematological malignancies, with a high risk of progression to acute myeloid leukemia (AML). To explore the role of acquired mutations in MDS, 111 MDS-associated genes were screened using next-generation sequencing (NGS), in 125 patients. One or more mutations were detected in 84% of the patients. Some gene mutations are specific for MDS and were associated with disease subtypes, and the patterns of mutational pathways could be associated with progressive MDS. The patterns, frequencies and functional pathways of gene mutations are different, but somehow related, between MDS and AML. Multivariate analysis suggested that patients with ≥ 2 mutations had poor progression-free survival, while GATA1/GATA2, DNMT3A and KRAS/NRAS mutations were associated with poor overall survival. Based on a novel system combining IPSS-R and molecular markers, these MDS patients were further divided into 3 more accurate prognostic subgroups. A panel of 11 target genes was proposed for genetic profiling of MDS. The study offers new insights into the molecular signatures of MDS and the genetic consistency between MDS and AML. Furthermore, results indicate that MDS could be classified by mutation combinations to guide the administration of individualized therapeutic interventions.

Molecular and genetic alterations associated with therapy resistance and relapse of acute myeloid leukemia

Background

The majority of individuals with acute myeloid leukemia (AML) respond to initial chemotherapy and achieve a complete remission, yet only a minority experience long-term survival because a large proportion of patients eventually relapse with therapy-resistant disease. Relapse therefore represents a central problem in the treatment of AML. Despite this, and in contrast to the extensive knowledge about the molecular events underlying the process of leukemogenesis, information about the mechanisms leading to therapy resistance and relapse is still limited.

Purpose and content of review

Recently, a number of studies have aimed to fill this gap and provided valuable information about the clonal composition and evolution of leukemic cell populations during the course of disease, and about genetic, epigenetic, and gene expression changes associated with relapse. In this review, these studies are summarized and discussed, and the data reported in them are compiled in order to provide a resource for the identification of molecular aberrations recurrently acquired at, and thus potentially contributing to, disease recurrence and the associated therapy resistance. This survey indeed uncovered genetic aberrations with known associations with therapy resistance that were newly gained at relapse in a subset of patients. Furthermore, the expression of a number of protein coding and microRNA genes was reported to change between diagnosis and relapse in a statistically significant manner.

Conclusions

Together, these findings foster the expectation that future studies on larger and more homogeneous patient cohorts will uncover pathways that are robustly associated with relapse, thus representing potential targets for rationally designed therapies that may improve the treatment of patients with relapsed AML, or even facilitate the prevention of relapse in the first place.

Electronic supplementary material

The online version of this article (doi:10.1186/s13045-017-0416-0) contains supplementary material, which is available to authorized users.

Inhibition of DNA and Histone Methylation by 5-Aza-2'-Deoxycytidine (Decitabine) and 3-Deazaneplanocin-A on Antineoplastic Action and Gene Expression in Myeloid Leukemic Cells

Epigenetic alterations play an important role in the development of acute myeloid leukemia (AML) by silencing of genes that suppress leukemogenesis and differentiation. One of the key epigenetic changes in AML is gene silencing by DNA methylation. The importance of this alteration is illustrated by the induction of remissions in AML by 5-aza-2′-deoxycytidine (5-AZA-CdR, decitabine), a potent inhibitor of DNA methylation. However, most patients induced into remission by 5-AZA-CdR will relapse, suggesting that a second agent should be sought to increase the efficacy of this epigenetic therapy. An interesting candidate for this purpose is 3-deazaneplanocin A (DZNep). This analog inhibits EZH2, a histone methyltransferase that trimethylates lysine 27 histone H3 (H3K27me3), a marker for gene silencing. This second epigenetic silencing mechanism also plays an important role in leukemogenesis as shown in preclinical studies where DZNep exhibits potent inhibition of colony formation by AML cells. We reported previously that 5-AZA-CdR in combination with DZNep exhibits a synergistic antineoplastic action against human HL-60 AML cells and the synergistic activation of several tumor suppressor genes. In this report, we showed that this combination also induced a synergistic activation of apoptosis in HL-60 cells. The synergistic antineoplastic action of 5-AZA-CdR plus DZNep was also observed on a second human myeloid leukemia cell line, AML-3. In addition, 5-AZA-CdR in combination with the specific inhibitors of EZH2, GSK-126, or GSK-343, also exhibited a synergistic antineoplastic action on both HL-60 and AML-3. The combined action of 5-AZA-CdR and DZNep on global gene expression in HL-60 cells was investigated in greater depth using RNA sequencing analysis. We observed that this combination of epigenetic agents exhibited a synergistic activation of hundreds of genes. The synergistic activation of so many genes that suppress malignancy by 5-AZA-CdR plus DZNep suggests that epigenetic gene silencing by DNA and histone methylation plays a major role in leukemogenesis. Targeting DNA and histone methylation is a promising approach that merits clinical investigation for the treatment of AML.

MLL-Rearranged Leukemias-An Update on Science and Clinical Approaches

The mixed-lineage leukemia 1 (MLL1) gene (now renamed Lysine [K]-specific MethylTransferase 2A or KMT2A) on chromosome 11q23 is disrupted in a unique group of acute leukemias. More than 80 different partner genes in these fusions have been described, although the majority of leukemias result from MLL1 fusions with one of about six common partner genes. Approximately 10% of all leukemias harbor MLL1 translocations. Of these, two patient populations comprise the majority of cases: patients younger than 1 year of age at diagnosis (primarily acute lymphoblastic leukemias) and young- to-middle-aged adults (primarily acute myeloid leukemias). A much rarer subgroup of patients with MLL1 rearrangements develop leukemia that is attributable to prior treatment with certain chemotherapeutic agents-so-called therapy-related leukemias. In general, outcomes for all of these patients remain poor when compared to patients with non-MLL1 rearranged leukemias. In this review, we will discuss the normal biological roles of MLL1 and its fusion partners, how these roles are hypothesized to be dysregulated in the context of MLL1 rearrangements, and the clinical manifestations of this group of leukemias. We will go on to discuss the progress in clinical management and promising new avenues of research, which may lead to more effective targeted therapies for affected patients.

Targeted therapies in the treatment of adult acute myeloid leukemias: current status and future perspectives

The rapid advancement of next-generation sequencing techniques and the identification of molecular driver events responsible for leukemia development are opening the door to new pharmacologic-targeted agents to tailor treatment of acute myeloid leukemia (AML) in individual patients. However, the use of targeted therapies in AML has met with only modest success. Molecular studies have identified AML subsets characterized by driver mutational events, such as NPM1, FLT3-ITD and IDH1-2 mutations, and have provided preclinical evidence that the targeting of these mutant molecules could represent a valuable therapeutic strategy. Recent studies have provided the first pieces of evidence that FLT3 targeting in FLT3-mutant AMLs, IDH1/2 inhibition in IDH-mutant AMLs and targeting membrane molecules preferentially expressed on leukemic progenitor/stem cells, such as CD33 and CD123, represent a clinically valuable strategy.

Outcome Comparison of Allogeneic versus Autologous Stem Cell Transplantation in Transformed Low-Grade Lymphoid Malignancies: A Systematic Review and Pooled Analysis of Comparative Studies

BACKGROUND

Some patients with low-grade lymphoid malignancies develop transformed disease, requiring stem cell transplantation (SCT). SCT outcomes in transformed low-grade lymphoid malignancies may differ from those of nontransformed disease or other aggressive non-Hodgkin lymphomas. We conducted a pooled analysis of the clinical outcomes of allogeneic versus high-dose therapy (HDT) with autologous SCT in adult patients with transformed low-grade lymphoid malignancies.

METHODS

A PubMed, EMBASE, and Cochrane search yielded 4 comparative studies reporting allogeneic versus HDT with autologous SCT outcomes in adults (age ≥18) with transformed low-grade lymphoid malignancies, including follicular, chronic/small lymphocytic, and marginal zone lymphoma. Risk ratio (RR) and 95% CI were calculated using random-effects models.

RESULTS

Rates for overall survival (OS) were 51.0 versus 69.5% (RR = 1.55, 95% CI 1.19-2.02, p = 0.001), rates of relapse were 37.3 versus 35.3% (RR = 1.04, 95% CI 0.70-1.55, p = 0.84), and rates of transplant-related mortality (TRM) were 33.3 versus 7.2% (RR = 4.52, 95% CI 2.75-7.43, p < 0.00001) for allogeneic versus autologous SCT. Previous rituximab treatment, reduced intensity conditioning regimen prior to SCT, or original pathology had no prognostic impact.

CONCLUSION

HDT followed by autologous SCT was associated with lower TRM and a better OS, but there was no difference in relapse versus allogeneic SCT. Autologous SCT may be the better therapeutic option, considering the second chance of allogeneic SCT in the case of relapse.

Molecular Changes During Acute Myeloid Leukemia (AML) Evolution and Identification of Novel Treatment Strategies Through Molecular Stratification

Acute myeloid leukemia (AML) is a hematopoietic malignancy characterized by impaired differentiation and uncontrollable proliferation of myeloid progenitor cells. Due to high relapse rates, overall survival for this rapidly progressing disease is poor. The significant challenge in AML treatment is disease heterogeneity stemming from variability in maturation state of leukemic cells of origin, genetic aberrations among patients, and existence of multiple disease clones within a single patient. Disease heterogeneity and the lack of biomarkers for drug sensitivity lie at the root of treatment failure as well as selective efficacy of AML chemotherapies and the emergence of drug resistance. Furthermore, standard-of-care treatment is aggressive, presenting significant tolerability concerns to the commonly advanced-age AML patient. In this review, we examine the concept and potential of molecular stratification, particularly with biologically relevant drug responses, in identifying low-toxicity precision therapeutic combinations and clinically relevant biomarkers for AML patient care as a way to overcome these challenges in AML treatment.

Effect of granulocyte colony-stimulating factor priming combined with low-dose cytarabine and homoharringtonine in higher risk myelodysplastic syndrome patients

As sensitization of leukemia cells with granulocyte colony-stimulating factor (G-CSF) can enhance the cytotoxicity of chemotherapy in myeloid malignancies, a pilot study was conducted in order to evaluate the effect of G-CSF priming combined with low-dose chemotherapy in patients with higher risk myelodysplastic syndrome (MDS). The regimen, G-HA, consisted of cytarabine (Ara-C) 7.5mg/m(2)/12h by subcutaneous injection, days 1-14, homoharringtonine (HHT) 1.5mg/m(2)/day by intravenous continuous infusion, days 1-14, and G-CSF 150mg/m(2)/day by subcutaneous injection, days 0-14. 56 patients were enrolled, 34 patients (61%, 95% confidence interval: 51.44-70.56%) achieved complete remission (CR). Median duration of neutropenia was 7days (ranging from 2 to 16days). Grade 1-2 nonhematologic toxicities were documented, including nausea and vomiting (5%), liver function abnormality (5%), and heart function abnormality (2%). No central nervous system toxicity was found. Mortality within the first 4 weeks was 4%. The G-HA regimen is effective in remission induction for higher risk MDS patients and well tolerated due to the acceptable toxicity in maintenance therapy in the patients who cannot undergo Hematopoietic cell transplantation (HCT).