Acute Myeloid Leukemia: Aging and Epigenetics

Clinical practice guidelines for molecular tumor marker, 2nd edition review part 2

In recent years, rapid advancement in gene/protein analysis technology has resulted in target molecule identification that may be useful in cancer treatment. Therefore, "Clinical Practice Guidelines for Molecular Tumor Marker, Second Edition" was published in Japan in September 2021. These guidelines were established to align the clinical usefulness of external diagnostic products with the evaluation criteria of the Pharmaceuticals and Medical Devices Agency. The guidelines were scoped for each tumor, and a clinical questionnaire was developed based on a serious clinical problem. This guideline was based on a careful review of the evidence obtained through a literature search, and recommendations were identified following the recommended grades of the Medical Information Network Distribution Services (Minds). Therefore, this guideline can be a tool for cancer treatment in clinical practice. We have already reported the review portion of "Clinical Practice Guidelines for Molecular Tumor Marker, Second Edition" as Part 1. Here, we present the English version of each part of the Clinical Practice Guidelines for Molecular Tumor Marker, Second Edition.

Vemurafenib induces senescence in acute myeloid leukemia and myelodysplastic syndrome by activating the HIPPO signaling pathway: implications for potential targeted therapy

BACKGROUND

The outcome of Acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) remain dismal despite the development of treatment. Targeted therapy is gaining more and more attention in improving prognosis.

METHODS

Expression of BRAF was analyzed by RT-qPCR in AML and MDS patients. Cells viability treated by drugs was measured by CCK-8 assay. Network pharmacology and RNA-sequence were used to analyze the mechanism of drugs and verified in vitro and xenograft tumor model.

RESULTS

Here we showed that BRAF was overexpressed in AML and MDS patients, and correlated with poor prognosis. The BRAF inhibitor-Vemurafenib (VEM) could significantly induce senescence, proliferation inhibition and apoptosis in AML cells, which can be enhanced by Bortezomib (BOR). This inhibitory effect was also verified in CD34 + cells derived from AML patients. Mechanistically, we showed that VEM combined with BOR could turn on HIPPO signaling pathway, thereby inducing cellular senescence in AML cells and xenograft mouse.

CONCLUSIONS

Taken together, our findings demonstrate a significant upregulation of BRAF expression in AML and MDS patients, which is associated with unfavorable clinical outcomes. We also discovered that the BRAF inhibitor Vemurafenib induces cellular senescence through activation of the HIPPO signaling pathway. Analysis of BRAF expression holds promise as a prognostic indicator and potential therapeutic target for individuals with AML and MDS.

Aging and Age-Related Epigenetic Drift in the Pathogenesis of Leukemia and Lymphomas: New Therapeutic Targets

One of the traits of cancer cells is abnormal DNA methylation patterns. The idea that age-related epigenetic changes may partially explain the increased risk of cancer in the elderly is based on the observation that aging is also accompanied by comparable changes in epigenetic patterns. Lineage bias and decreased stem cell function are signs of hematopoietic stem cell compartment aging. Additionally, aging in the hematopoietic system and the stem cell niche have a role in hematopoietic stem cell phenotypes linked with age, such as leukemia and lymphoma. Understanding these changes will open up promising pathways for therapies against age-related disorders because epigenetic mechanisms are reversible. Additionally, the development of high-throughput epigenome mapping technologies will make it possible to identify the "epigenomic identity card" of every hematological disease as well as every patient, opening up the possibility of finding novel molecular biomarkers that can be used for diagnosis, prediction, and prognosis.

Cell-free DNA 5-hydroxymethylcytosine is highly sensitive for MRD assessment in acute myeloid leukemia

Measurable residual disease (MRD) is an important biomarker in acute myeloid leukemia (AML). However, MRD cannot be detected in many patients using current methods. We developed a highly sensitive 5-hydroxymethylcytosine (5hmC) signature in cell-free DNA by analyzing 115 AML patients and 86 controls. The 5hmC method detected MRD in 20 of 29 patients with negative MRD by multiparameter flow cytometry and 11 of 14 patients with negative MRD by molecular methods. MRD detection by the 5hmC method was significantly associated with relapse-free survival. This novel method can be used in most AML patients and may significantly impact AML patient management.

Role of Diacylglycerol Kinases in Acute Myeloid Leukemia

Diacylglycerol kinases (DGKs) play dual roles in cell transformation and immunosurveillance. According to cancer expression databases, acute myeloid leukemia (AML) exhibits significant overexpression of multiple DGK isoforms, including DGKA, DGKD and DGKG, without a precise correlation with specific AML subtypes. In the TGCA database, high DGKA expression negatively correlates with survival, while high DGKG expression is associated with a more favorable prognosis. DGKA and DGKG also feature different patterns of co-expressed genes. Conversely, the BeatAML and TARGET databases show that high DGKH expression is correlated with shorter survival. To assess the suitability of DGKs as therapeutic targets, we treated HL-60 and HEL cells with DGK inhibitors and compared cell growth and survival with those of untransformed lymphocytes. We observed a specific sensitivity to R59022 and R59949, two poorly selective inhibitors, which promoted cytotoxicity and cell accumulation in the S phase in both cell lines. Conversely, the DGKA-specific inhibitors CU-3 and AMB639752 showed poor efficacy. These findings underscore the pivotal and isoform-specific involvement of DGKs in AML, offering a promising pathway for the identification of potential therapeutic targets. Notably, the DGKA and DGKH isoforms emerge as relevant players in AML pathogenesis, albeit DGKA inhibition alone seems insufficient to impair AML cell viability.

Epigenetic Mechanisms of Aging and Aging-Associated Diseases

Aging is an inevitable outcome of life, characterized by a progressive decline in tissue and organ function. At a molecular level, it is marked by the gradual alterations of biomolecules. Indeed, important changes are observed on the DNA, as well as at a protein level, that are influenced by both genetic and environmental parameters. These molecular changes directly contribute to the development or progression of several human pathologies, including cancer, diabetes, osteoporosis, neurodegenerative disorders and others aging-related diseases. Additionally, they increase the risk of mortality. Therefore, deciphering the hallmarks of aging represents a possibility for identifying potential druggable targets to attenuate the aging process, and then the age-related comorbidities. Given the link between aging, genetic, and epigenetic alterations, and given the reversible nature of epigenetic mechanisms, the precisely understanding of these factors may provide a potential therapeutic approach for age-related decline and disease. In this review, we center on epigenetic regulatory mechanisms and their aging-associated changes, highlighting their inferences in age-associated diseases.

Differentially Expressed Genes and Molecular Susceptibility to Human Age-Related Diseases

Mainstream transcriptome profiling of susceptibility versus resistance to age-related diseases (ARDs) is focused on differentially expressed genes (DEGs) specific to gender, age, and pathogeneses. This approach fits in well with predictive, preventive, personalized, participatory medicine and helps understand how, why, when, and what ARDs one can develop depending on their genetic background. Within this mainstream paradigm, we wanted to find out whether the known ARD-linked DEGs available in PubMed can reveal a molecular marker that will serve the purpose in anyone's any tissue at any time. We sequenced the periaqueductal gray (PAG) transcriptome of tame versus aggressive rats, identified rat-behavior-related DEGs, and compared them with their known homologous animal ARD-linked DEGs. This analysis yielded statistically significant correlations between behavior-related and ARD-susceptibility-related fold changes (log₂ values) in the expression of these DEG homologs. We found principal components, PC1 and PC2, corresponding to the half-sum and the half-difference of these log₂ values, respectively. With the DEGs linked to ARD susceptibility and ARD resistance in humans used as controls, we verified these principal components. This yielded only one statistically significant common molecular marker for ARDs: an excess of Fcγ receptor IIb suppressing immune cell hyperactivation.

The potential role of the thymus in immunotherapies for acute myeloid leukemia

Understanding the factors which shape T-lymphocyte immunity is critical for the development and application of future immunotherapeutic strategies in treating hematological malignancies. The thymus, a specialized central lymphoid organ, plays important roles in generating a diverse T lymphocyte repertoire during the infantile and juvenile stages of humans. However, age-associated thymic involution and diseases or treatment associated injury result in a decline in its continuous role in the maintenance of T cell-mediated anti-tumor/virus immunity. Acute myeloid leukemia (AML) is an aggressive hematologic malignancy that mainly affects older adults, and the disease's progression is known to consist of an impaired immune surveillance including a reduction in naïve T cell output, a restriction in T cell receptor repertoire, and an increase in frequencies of regulatory T cells. As one of the most successful immunotherapies thus far developed for malignancy, T-cell-based adoptive cell therapies could be essential for the development of a durable effective treatment to eliminate residue leukemic cells (blasts) and prevent AML relapse. Thus, a detailed cellular and molecular landscape of how the adult thymus functions within the context of the AML microenvironment will provide new insights into both the immune-related pathogenesis and the regeneration of a functional immune system against leukemia in AML patients. Herein, we review the available evidence supporting the potential correlation between thymic dysfunction and T-lymphocyte impairment with the ontogeny of AML (II-VI). We then discuss how the thymus could impact current and future therapeutic approaches in AML (VII). Finally, we review various strategies to rejuvenate thymic function to improve the precision and efficacy of cancer immunotherapy (VIII).

Clinical Implication of DNMT3A and TET2 Genes Mutations in Cytogenetically Normal Acute Myeloid Leukemia

BACKGROUND

Refining risk stratification of cytogenetically  normal AML (CN-AML) cases is important for decision making and tailoring of therapy. In this context genetic and epigenetic mutations was considered. Among these epigenetic regulators are DNMT3A & TET2 genes. Therefore, the aim of  this study was to determine the prevalence of DNMT3A and TET2 genes mutations and their impact on the outcome of  adult AML patients.

SUBJECTS AND METHODS

The present study is cross sectional study which was conducted on 39 adult CN-AML patients at diagnosis. For all included patients sanger sequencing was done for DNMT3A exon 23 and TET2 exon 3 genes.

RESULTS

DNMT3A mutations were detected in 8 of 39 patients (20.5%), and in 5 of 39 patients(12.8%) in TET gene. Two CN-AML  patients had combined mutations in both genes. All of the mutations detected were missense and only one was frame shift. Mutated TET2 or DNMT3A genes were significantly associated with failure of complete remission (CR) (p <0.001), higher mortality rate, shorter OS (mean=16 versus 22.7 months) and shorter DFS (mean= 9.5 versus 21.4 months) when compared to non-mutated ones.

CONCLUSION

Mutated TET2 and DNMT3A detection define a subgroup of CN-AML patients with poor outcome.

The transcriptomic landscape of elderly acute myeloid leukemia identifies B7H3 and BANP as a favorable signature in high-risk patients

Acute myeloid leukemia (AML) in the elderly remains a clinical challenge, with a five-year overall survival rate below 10%. The current ELN 2017 genetic risk classification considers cytogenetic and mutational characteristics to stratify fit AML patients into different prognostic groups. However, this classification is not validated for elderly patients treated with a non-intensive approach, and its performance may be suboptimal in this context. Indeed, the transcriptomic landscape of AML in the elderly has been less explored and it might help stratify this group of patients. In the current study, we analyzed the transcriptome of 224 AML patients > 65 years-old at diagnosis treated in the Spanish PETHEMA-FLUGAZA clinical trial in order to identify new prognostic biomarkers in this population. We identified a specific transcriptomic signature for high-risk patients with mutated TP53 or complex karyotype, revealing that low expression of B7H3 gene with high expression of BANP gene identifies a subset of high-risk AML patients surviving more than 12 months. This result was further validated in the BEAT AML cohort. This unique signature highlights the potential of transcriptomics to identify prognostic biomarkers in in elderly AML.

Global disease burden and trends of leukemia attributable to occupational risk from 1990 to 2019: An observational trend study

Background

Leukemia caused by occupational risk is a problem that needs more attention and remains to be solved urgently, especially for acute lymphoid leukemia (ALL), acute myeloid leukemia (AML), and chronic lymphoid leukemia (CLL). However, there is a paucity of literature on this issue. We aimed to assess the global burden and trends of leukemia attributable to occupational risk from 1990 to 2019.

Methods

This observational trend study was based on the Global Burden of Disease (GBD) 2019 database, the global deaths, and disability-adjusted life years (DALYs), which were calculated to quantify the changing trend of leukemia attributable to occupational risk, were analyzed by age, year, geographical location, and socio-demographic index (SDI), and the corresponding estimated annual percentage change (EAPC) values were calculated.

Results

Global age-standardized DALYs and death rates of leukemia attributable to occupational risk presented significantly decline trends with EAPC [-0.38% (95% CI: -0.58 to -0.18%) for DALYs and -0.30% (95% CI: -0.45 to -0.146%) for death]. However, it was significantly increased in people aged 65-69 years [0.42% (95% CI: 0.30-0.55%) for DALYs and 0.38% (95% CI: 0.26-0.51%) for death]. At the same time, the age-standardized DALYs and death rates of ALL, AML, and CLL were presented a significantly increased trend with EAPCs [0.78% (95% CI: 0.65-0.91%), 0.87% (95% CI: 0.81-0.93%), and 0.66% (95% CI: 0.51-0.81%) for DALYs, respectively, and 0.75% (95% CI: 0.68-0.82%), 0.96% (95% CI: 0.91-1.01%), and 0.55% (95% CI: 0.43-0.68%) for death], respectively. The ALL, AML, and CLL were shown an upward trend in almost all age groups.

Conclusion

We observed a substantial reduction in leukemia due to occupational risks between 1990 and 2019. However, the people aged 65-69 years and burdens of ALL, AML, and CLL had a significantly increased trend in almost all age groups. Thus, there remains an urgent need to accelerate efforts to reduce leukemia attributable to occupational risk-related death burden in this population and specific causes.

Cellular enlargement - A new hallmark of aging?

Years of important research has revealed that cells heavily invest in regulating their size. Nevertheless, it has remained unclear why accurate size control is so important. Our recent study using hematopoietic stem cells (HSCs) in vivo indicates that cellular enlargement is causally associated with aging. Here, we present an overview of these findings and their implications. Furthermore, we performed a broad literature analysis to evaluate the potential of cellular enlargement as a new aging hallmark and to examine its connection to previously described aging hallmarks. Finally, we highlight interesting work presenting a correlation between cell size and age-related diseases. Taken together, we found mounting evidence linking cellular enlargement to aging and age-related diseases. Therefore, we encourage researchers from seemingly unrelated areas to take a fresh look at their data from the perspective of cell size.

DNA methylation changes and inflammaging in aging-associated diseases

Aging as an inevitable phenomenon is associated with pervasive changes in physiological functions. There is a relationship between aging and the increase of several chronic diseases. Most age-related disorders are accompanied by an underlying chronic inflammatory state, as demonstrated by local infiltration of inflammatory cells and greater levels of proinflammatory cytokines in the bloodstream. Within inflammaging, many epigenetic events, especially DNA methylation, change. During the aging process, due to aberrations of DNA methylation, biological processes are disrupted, leading to the emergence or progression of a variety of human diseases, including cancer, neurodegenerative disorders, cardiovascular disease and diabetes. The focus of this review is on DNA methylation, which is involved in inflammaging-related activities, and how its dysregulation leads to human disorders.

Cell-free DNA 5-hydroxymethylcytosine is an emerging marker of acute myeloid leukemia

Aberrant changes in 5-hydroxymethylcytosine (5hmC) are a unique epigenetic feature in many cancers including acute myeloid leukemia (AML). However, genome-wide analysis of 5hmC in plasma cell-free DNA (cfDNA) remains unexploited in AML patients. We used a highly sensitive and robust nano-5hmC-Seal technology and profiled genome-wide 5hmC distribution in 239 plasma cfDNA samples from 103 AML patients and 81 non-cancer controls. We developed a 5hmC diagnostic model that precisely differentiates AML patients from controls with high sensitivity and specificity. We also developed a 5hmC prognostic model that accurately predicts prognosis in AML patients. High weighted prognostic scores (wp-scores) in AML patients were significantly associated with adverse overall survival (OS) in both training (P = 3.31e-05) and validation (P = 0.000464) sets. The wp-score was also significantly associated with genetic risk stratification and displayed dynamic changes with varied disease burden. Moreover, we found that high wp-scores in a single gene, BMS1 and GEMIN5 predicted OS in AML patients in both the training set (P = 0.023 and 0.031, respectively) and validation set (P = 9.66e-05 and 0.011, respectively). Lastly, our study demonstrated the genome-wide landscape of DNA hydroxymethylation in AML and revealed critical genes and pathways related to AML diagnosis and prognosis. Our data reveal plasma cfDNA 5hmC signatures as sensitive and accurate markers for AML diagnosis and prognosis. Plasma cfDNA 5hmC analysis will be an effective and minimally invasive tool for AML management.

Identification and validation of a siglec-based and aging-related 9-gene signature for predicting prognosis in acute myeloid leukemia patients

Background

Acute myeloid leukemia (AML) is a group of highly heterogenous and aggressive blood cancer. Despite recent progress in its diagnosis and treatment, patient outcome is variable and drug resistance results in increased mortality. The siglec family plays an important role in tumorigenesis and aging. Increasing age is a risk factor for AML and cellular aging contributes to leukemogenesis via various pathways.

Methods

The differential expression of the siglec family was compared between 151 AML patients and 70 healthy controls, with their information downloaded from TCGA and GTEx databases, respectively. How siglec expression correlated to AML patient clinical features, immune cell infiltration, drug resistance and survival outcome was analyzed. Differentially expressed genes in AML patients with low- and high-expressed siglec9 and siglec14 were analyzed and functionally enriched. The aging-related gene set was merged with the differentially expressed genes in AML patients with low and high expression of siglec9, and merged genes were subjected to lasso regression analysis to construct a novel siglec-based and aging-related prognostic model. The prediction model was validated using a validation cohort from GEO database (GSE106291).

Results

The expression levels of all siglec members were significantly altered in AML. The expression of siglecs was significantly correlated with AML patient clinical features, immune cell infiltration, drug resistance, and survival outcome. Based on the differentially expressed genes and aging-related gene set, we developed a 9-gene prognostic model and decision curve analysis revealed the net benefit generated by our prediction model. The siglec-based and aging-related 9-gene prognostic model was tested using a validation data set, in which AML patients with higher risk scores had significantly reduced survival probability. Time-dependent receiver operating characteristic curve and nomogram were plotted and showed the diagnostic accuracy and predictive value of our 9-gene prognostic model, respectively.

Conclusions

Overall, our study indicates the important role of siglec family in AML and the good performance of our novel siglec-based and aging-related 9-gene signature in predicting AML patient outcome.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12859-022-04841-5.

Epigenetic silencing of E-cadherin gene induced by lncRNA MALAT-1 in acute myeloid leukaemia

Background

Epigenetic abnormalities in acute myeloid leukaemia provide us with a target for novel therapeutic strategies. The aim of the study was to verify the epigenetic regulatory mechanism of E‐cadherin gene silencing induced by long non‐coding RNA MALAT‐1 in AML.

Methods

Expression of MALAT‐1, E‐cadherin, EZH2, SUZ12 and EED genes in AML patients was detected by RT‐qPCR. After MALAT‐1 silencing in AML cell lines, levels of the E‐cadherin, EZH2, SUZ12, EED, DNMT1, DNMT3A and DNMT3B genes and encoded proteins were detected by RT‐qPCR and Western blotting. The level of CpG island methylation and trimethylation modification of histone H3K27 in the promoter region of E‐cadherin was detected by pyrosequencing and ChIP‐qPCR. RIP‐qPCR was used to detect the interaction between MALAT‐1 and proteins.

Results

MALAT‐1, EZH2 and EED gene expression was markedly increased in AML patients with E‐cadherin down‐regulation. A positive correlation between EZH2 or SUZ12 and MALAT‐1 expression was observed. After MALAT‐1 silencing, the expression of E‐cadherin was up‐regulated, whereas the expression of EZH2, SUZ12, DNMT1, DNMT3A and DNMT3B was down‐regulated. Results of Western blotting were consistent with those of RT‐qPCR. Methylation levels of E‐cadherin in AML patients were higher than that in normal controls, which appeared to increase with age. Methylation of the CpG island and H3K27 trimethylation of E‐cadherin were decreased after MALAT‐1 silencing. RIP‐qPCR suggested that MALAT‐1 might be enriched by EZH2 and SUZ12.

Conclusion

Our findings verified that MALAT‐1 might lead to the transcriptional silencing of E‐cadherin gene through the trimethylation of H3K27 mediated by recruiting EZH2 and SUZ12.

Oncogenic ZMYND11-MBTD1 fusion protein anchors the NuA4/TIP60 histone acetyltransferase complex to the coding region of active genes

A recurrent chromosomal translocation found in acute myeloid leukemia leads to an in-frame fusion of the transcription repressor ZMYND11 to MBTD1, a subunit of the NuA4/TIP60 histone acetyltransferase complex. To understand the abnormal molecular events that ZMYND11-MBTD1 expression can create, we perform a biochemical and functional characterization comparison to each individual fusion partner. ZMYND11-MBTD1 is stably incorporated into the endogenous NuA4/TIP60 complex, leading to its mislocalization on the body of genes normally bound by ZMYND11. This can be correlated to increased chromatin acetylation and altered gene transcription, most notably on the MYC oncogene, and alternative splicing. Importantly, ZMYND11-MBTD1 expression favors Myc-driven pluripotency during embryonic stem cell differentiation and self-renewal of hematopoietic stem/progenitor cells. Altogether, these results indicate that the ZMYND11-MBTD1 fusion functions primarily by mistargeting the NuA4/TIP60 complex to the body of genes, altering normal transcription of specific genes, likely driving oncogenesis in part through the Myc regulatory network.

Male rat leukocyte population dynamics predict a window for intervention in aging

Many age-associated changes in the human hematopoietic system have been reproduced in murine models; however, such changes have not been as robustly explored in rats despite the fact these larger rodents are more physiologically similar to humans. We examined peripheral blood of male F344 rats ranging from 3 to 27 months of age and found significant age-associated changes with distinct leukocyte population shifts. We report CD25⁺ CD4⁺ population frequency is a strong predictor of healthy aging, generate a model using blood parameters, and find rats with blood profiles that diverge from chronologic age indicate debility; thus, assessments of blood composition may be useful for non-lethal disease profiling or as a surrogate measure for efficacy of aging interventions. Importantly, blood parameters and DNA methylation alterations, defined distinct juncture points during aging, supporting a non-linear aging process. Our results suggest these inflection points are important considerations for aging interventions. Overall, we present rat blood aging metrics that can serve as a resource to evaluate health and the effects of interventions in a model system physiologically more reflective of humans.

Our blood contains many types of white blood cells, which play important roles in defending the body against infections and other threats to our health. The number of these cells changes with age, and this in turn contributes to many other alterations that happen in the body as we get older. For example, the immune system generally gets weaker at fighting infections and preventing other cells from developing into cancer. On top of that, the white blood cells themselves can become cancerous, resulting in several types of blood cancer that are more likely to happen in older people.

Many previous studies have examined how the number of white blood cells changes with age in humans and mice. However, our understanding of this process in rats is still poor, despite the fact that the way the human body works has more in common with the rat body than the mouse body.

Here, Yanai, Dunn et al. have studied samples of blood from rats between three to 27 months old. The experiments found that it is possible to accurately predict the age of healthy rats by measuring the frequency of populations of white blood cells, especially a certain type known as CD25+ CD4+ cells. If the animals had any form of illness, their predicted age deviated from their actual age. Furthermore, while some changes in the blood were gradual and continuous, others displayed distinct shifts when the rats reached specific ages.

In the future, these findings may be used as a tool to help researchers diagnose illnesses in rats before the animals develop symptoms, or to more easily establish if a treatment is having a positive effect on the rats’ health. The work of Yanai, Dunn et al. also provides new insights into aging that could potentially aid the design of new screening methods to predict cancer and intervene using a model system that is more similar to humans.

Targeting TP53-Mutated Acute Myeloid Leukemia: Research and Clinical Developments

TP53 is a key tumor suppressor gene that plays an important role in regulating apoptosis, senescence, and DNA damage repair in response to cellular stress. Although somewhat rare, TP53-mutated AML has been identified as an important molecular subgroup with a prognosis that is arguably the worst of any. Survival beyond one year is rare after induction chemotherapy with or without consolidative allogeneic stem cell transplant. Although response rates have been improved with hypomethylating agents, outcomes remain particularly poor due to short response duration. Improvements in our understanding of AML genetics and biology have led to a surge in novel treatment options, though the clinical applicability of these agents in TP53-mutated disease remains largely unknown. This review will focus on the epidemiology, molecular characteristics, and clinical significance of TP53 mutations in AML as well as emerging treatment options that are currently being studied.

Grape seed proanthocyanidin extract induces apoptosis of HL-60/ADR cells via the Bax/Bcl-2 caspase-3/9 signaling pathway

Background

Our previous study detailed the direct induction of apoptosis by grape seed proanthocyanidin extract (GSPE) in a multidrug resistant human acute myeloid leukemia (AML) HL-60/adriamycin (HL-60/ADR) cell line, although the mechanism of this effect was not detailed. This study aims to elucidate the mechanism underlying GSPE-induced cell apoptosis in HL-60/ADR cells.

Methods

HL-60/ADR cells were studied to evaluate effects of GSPE (0–100 µg/mL); a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was employed to identify the cytotoxic effect of varying GSPE concentrations. Trypan blue staining was used to observe changes in cell viability; flow cytometry assays were used to verify apoptosis. Expression of Bax and Bcl-2 mRNA was analyzed using real-time polymerase chain reaction (PCR). Activity of caspase-3 and caspase-9 was also detected.

Results

Here, GSPE was found to inhibit HL-60/ADR cell growth and induce cell apoptosis in a dose-dependent manner. Real-time PCR findings revealed that GSPE concentrations above 75 µg/mL significantly increase expression of Bax mRNA (P<0.001). GSPE concentrations above 25 µg/mL were found to significantly decrease expression of Bcl-2 mRNA (P<0.01), while concentrations above 50 µg/mL were found to significantly increase caspase-3 activity after 6, 12 and 24 h (P<0.01). However, only 100 µg/mL GSPE was found to significantly increase caspase-9 activity (P<0.001 at 6 and 12 h; P<0.05 at 24 h).

Conclusions

GSPE inhibits the proliferation of HL-60/ADR cells by the induction of apoptosis in a dose-dependent manner via the Bax/Bcl-2 caspase-3/9 signaling pathway.

3-Ketodihydrosphingosine reductase maintains ER homeostasis and unfolded protein response in leukemia

Sphingolipids and their metabolic pathways have been implicated in disease development and therapeutic response; however, the detailed mechanisms remain unclear. Using a sphingolipid network focused CRISPR/Cas9 library screen, we identified an endoplasmic reticulum (ER) enzyme, 3-Ketodihydrosphingosine reductase (KDSR), to be essential for leukemia cell maintenance. Loss of KDSR led to apoptosis, cell cycle arrest, and aberrant ER structure. Transcriptomic analysis revealed the indispensable role of KDSR in maintaining the unfolded protein response (UPR) in ER. High-density CRISPR tiling scan and sphingolipid mass spectrometry pinpointed the critical role of KDSR's catalytic function in leukemia. Mechanistically, depletion of KDSR resulted in accumulated 3-ketodihydrosphingosine (KDS) and dysregulated UPR checkpoint proteins PERK, ATF6, and ATF4. Finally, our study revealed the synergism between KDSR suppression and pharmacologically induced ER-stress, underscoring a therapeutic potential of combinatorial targeting sphingolipid metabolism and ER homeostasis in leukemia treatment.

BCL-2 Expression in AML Patients over 65 Years: Impact on Outcomes across Different Therapeutic Strategies

BCL-2 overexpression has been associated with resistance to chemotherapy and reduced survival in acute myeloid leukemia (AML), but few data are available in elderly patients, a subset accounting for majority of AML cases and with dismal prognosis. We retrospectively analyzed 113 AML patients aged ≥65 years treated with 3 + 7 chemotherapy (n = 51) or hypomethylating agents (HMAs) (n = 62), evaluating the role of BCL-2 expression on complete remission (CR) and overall survival (OS). BCL-2 was expressed in 81 patients (72%), more frequently in those with unfavorable cytogenetic-molecular risk. CR was achieved in 34.5% cases, without differences according to BCL-2 expression or induction therapy. In the whole population 1-year OS was 39%, similar in BCL-2+ and BCL-2- cases. In BCL-2 positive patients OS was superior with HMAs (56% vs. 25% with 3 + 7; p = 0.02), while no advantage for HMA was found in BCL-2 negative cases (36% vs. 27% for 3 + 7). Therapy with HMAs was the only factor associated with longer OS in BCL-2+ AML by multivariable analysis. Use of HMAs, possibly in combination with BCL-2 inhibitors, appears to be particularly appealing in BCL2+ AML, where it is associated with superior survival.

Evolving Therapeutic Approaches for Older Patients with Acute Myeloid Leukemia in 2021

Simple Summary

The better understanding of disease biology, the availability of new effective drugs and the increased awareness of patients’ heterogeneity in terms of fitness and personal expectations has made the current treatment paradigm of AML in the elderly very challenging. Here, we discuss the evolving criteria used to define eligibility for induction chemotherapy and transplantation, the introduction of new agents in the treatment of patients with very different clinical conditions, the implications of precision medicine and the importance of quality of life and supportive care, proposing a simplified algorithm that we follow in 2021.

Abstract

Acute myeloid leukemia (AML) in older patients is characterized by unfavorable prognosis due to adverse disease features and a high rate of treatment-related complications. Classical therapeutic options range from intensive chemotherapy in fit patients, potentially followed by allogeneic hematopoietic cell transplantation (allo-HCT), to hypomethylating agents or palliative care alone for unfit/frail ones. In the era of precision medicine, the treatment paradigm of AML is rapidly changing. On the one hand, a plethora of new targeted drugs with good tolerability profiles are becoming available, offering the possibility to achieve a prolonged remission to many patients not otherwise eligible for more intensive therapies. On the other hand, better tools to assess patients’ fitness and improvements in the selection and management of those undergoing allo-HCT will hopefully reduce treatment-related mortality and complications. Importantly, a detailed genetic characterization of AML has become of paramount importance to choose the best therapeutic option in both intensively treated and unfit patients. Finally, improving supportive care and quality of life is of major importance in this age group, especially for the minority of patients that are still candidates for palliative care because of very poor clinical conditions or unwillingness to receive active treatments. In the present review, we discuss the evolving approaches in the treatment of older AML patients, which is becoming increasingly challenging following the advent of new effective drugs for a very heterogeneous and complex population.

The contributory roles of histone deacetylases (HDACs) in hematopoiesis regulation and possibilities for pharmacologic interventions in hematologic malignancies

Although the definitive role of epigenetic modulations in a wide range of hematologic malignancies, spanning from leukemia to lymphoma and multiple myeloma, has been evidenced, few articles reviewed the task. Given the high accessibility of histone deacetylase (HDACs) to necessary transcription factors involved in hematopoiesis, this review aims to outline physiologic impacts of these enzymes in normal hematopoiesis, and also to outline the original data obtained from international research laboratories on their regulatory role in the differentiation and maturation of different hematopoietic lineages. Questions on how aberrant expression of HDACs contributes to the formation of hematologic malignancies are also responded, because these classes of enzymes have a respectable share in the development, progression, and recurrence of leukemia, lymphoma, and multiple myeloma. The last section provides a special focus on the therapeutic perspectiveof HDACs inhibitors, either as single agents or in a combined-modal strategy, in these neoplasms. In conclusion, optimizing the dose and the design of more patient-tailored inhibitors, while maintaining low toxicity against normal cells, will help improve clinical outcomes of HDAC inhibitors in hematologic malignancies.

Bioisosteric replacements of the indole moiety for the development of a potent and selective PI3Kδ inhibitor: Design, synthesis and biological evaluation

Based on indole scaffold, a potent and selective phosphoinositide 3-kinase delta (PI3Kδ) inhibitor, namely FD223, was developed by the bioisosteric replacement drug discovery approach and studied for the treatment of acute myeloid leukemia (AML). In vitro studies revealed that FD223 displays high potency (IC₅₀ = 1 nM) and selectivity (29-51 fold over other PI3K isoforms) against PI3Kδ, and exhibits efficient inhibition of the proliferation of AML cell lines (MOLM-16, HL-60, EOL-1 and KG-1) by suppressing p-AKT Ser473 thus causing G1 phase arrest during the cell cycle. Further given the favorable pharmacokinetic (PK) profiles of FD223, in vivo studies were evaluated using xenograft model in nude mice, confirming its significant antitumor efficacy meanwhile with no observable toxicity. All these results are comparable to the positive group of Idelalisib (CAL-101), indicating that FD223 has potential for further development as a promising PI3Kδ inhibitor for the treatment of leukemia such as AML.

Meta-analysis of gene signatures and key pathways indicates suppression of JNK pathway as a regulator of chemo-resistance in AML

The pathways and robust deregulated gene signatures involved in AML chemo-resistance are not fully understood. Multiple subgroups of AMLs which are under treatment of various regimens seem to have similar regulatory gene(s) or pathway(s) related to their chemo-resistance phenotype. In this study using gene set enrichment approach, deregulated genes and pathways associated with relapse after chemotherapy were investigated in AML samples. Five AML libraries compiled from GEO and ArrayExpress repositories were used to identify significantly differentially expressed genes between chemo-resistance and chemo-sensitive groups. Functional and pathway enrichment analysis of differentially expressed genes was performed to assess molecular mechanisms related to AML chemotherapeutic resistance. A total of 34 genes selected to be differentially expressed in the chemo-resistance compared to the chemo-sensitive group. Among the genes selected, c-Jun, AKT3, ARAP3, GABBR1, PELI2 and SORT1 are involved in neurotrophin, estrogen, cAMP and Toll-like receptor signaling pathways. All these pathways are located upstream and regulate JNK signaling pathway which functions as a key regulator of cellular apoptosis. Our expression data are in favor of suppression of JNK pathway, which could induce pro-apoptotic gene expression as well as down regulation of survival factors, introducing this pathway as a key regulator of drug-resistance development in AML.

Proteomic Studies of Primary Acute Myeloid Leukemia Cells Derived from Patients Before and during Disease-Stabilizing Treatment Based on All-Trans Retinoic Acid and Valproic Acid

All-trans retinoic acid (ATRA) and valproic acid (VP) have been tried in the treatment of non-promyelocytic variants of acute myeloid leukemia (AML). Non-randomized studies suggest that the two drugs can stabilize AML and improve normal peripheral blood cell counts. In this context, we used a proteomic/phosphoproteomic strategy to investigate the in vivo effects of ATRA/VP on human AML cells. Before starting the combined treatment, AML responders showed increased levels of several proteins, especially those involved in neutrophil degranulation/differentiation, M phase regulation and the interconversion of nucleotide di- and triphosphates (i.e., DNA synthesis and binding). Several among the differentially regulated phosphorylation sites reflected differences in the regulation of RNA metabolism and apoptotic events at the same time point. These effects were mainly caused by increased cyclin dependent kinase 1 and 2 (CDK1/2), LIM domain kinase 1 and 2 (LIMK1/2), mitogen-activated protein kinase 7 (MAPK7) and protein kinase C delta (PRKCD) activity in responder cells. An extensive effect of in vivo treatment with ATRA/VP was the altered level and phosphorylation of proteins involved in the regulation of transcription/translation/RNA metabolism, especially in non-responders, but the regulation of cell metabolism, immune system and cytoskeletal functions were also affected. Our analysis of serial samples during the first week of treatment suggest that proteomic and phosphoproteomic profiling can be used for the early identification of responders to ATRA/VP-based treatment.

Cancer epigenetics: Past, present and future

Cancer was thought to be caused solely by genetic mutations in oncogenes and tumor suppressor genes. In the last 35 years, however, epigenetic changes have been increasingly recognized as another primary driver of carcinogenesis and cancer progression. Epigenetic deregulation in cancer often includes mutations and/or aberrant expression of chromatin-modifying enzymes, their associated proteins, and even non-coding RNAs, which can alter chromatin structure and dynamics. This leads to changes in gene expression that ultimately contribute to the emergence and evolution of cancer cells. Studies of the deregulation of chromatin modifiers in cancer cells have reshaped the way we approach cancer and guided the development of novel anticancer therapeutics that target epigenetic factors. There remain, however, a number of unanswered questions in this field that are the focus of present research. Areas of particular interest include the actions of emerging classes of epigenetic regulators of carcinogenesis and the tumor microenvironment, as well as epigenetic tumor heterogeneity. In this review, we discuss past findings on epigenetic mechanisms of cancer, current trends in the field of cancer epigenetics, and the directions of future research that may lead to the identification of new prognostic markers for cancer and the development of more effective anticancer therapeutics.

Long noncoding RNAs have pivotal roles in chemoresistance of acute myeloid leukemia

Many patients with acute myeloid leukemia (AML) experience poor outcomes following traditional high-dose chemotherapies and complete remission rates remain suboptimal. Chemoresistance is an obstacle to effective chemotherapy and the precise mechanisms involved remain to be determined. Recently, long noncoding RNAs (lncRNAs) have been identified as relevant factors in the development of drug resistance in patients with AML. Furthermore, accumulating data support the importance of lncRNAs as potentially useful novel therapeutic targets in many cancers. Here, we review the role of lncRNAs in the development and induction of the chemoresistance in AML, and suggest lncRNAs as novel molecular markers for diagnosis, prediction of patient response to chemotherapy, and novel therapeutic targets for AML.

Cellular senescence and hematological malignancies: From pathogenesis to therapeutics

Cellular senescence constitutes a permanent state of cell cycle arrest in proliferative cells induced by different stresses. The exploration of tumor pathogenesis and therapies has been a research hotspot in recent years. Cellular senescence is a significant mechanism to prevent the proliferation of potential tumor cells, but it can also promote tumor growth. Increasing evidence suggests that cellular senescence is involved in the pathogenesis and development of hematological malignancies, including leukemia, myelodysplastic syndrome (MDS) and multiple myeloma (MM). Cellular senescence is associated with functional decline of hematopoietic stem cells (HSCs) and increased risk of hematological malignancies. Moreover, the bone marrow (BM) microenvironment has a crucial regulatory effect in the process of these diseases. The senescence-associated secretory phenotype (SASP) in the BM microenvironment establishes a protumor environment that supports the proliferation and survival of tumor cells. Therefore, a series of therapeutic strategies targeting cellular senescence have been gradually developed, including the induction of cellular senescence and elimination of senescent cells. This review systematically summarizes the emerging information describing the roles of cellular senescence in tumorigenesis and potential clinical applications, which may be beneficial for designing rational therapeutic strategies for various hematopoietic malignancies.

Biological characteristics of aging in human acute myeloid leukemia cells: the possible importance of aldehyde dehydrogenase, the cytoskeleton and altered transcriptional regulation

Patients with acute myeloid leukemia (AML) have a median age of 65-70 years at diagnosis. Elderly patients have more chemoresistant disease, and this is partly due to decreased frequencies of favorable and increased frequencies of adverse genetic abnormalities. However, aging-dependent differences may also contribute. We therefore compared AML cell proteomic and phosphoproteomic profiles for (i) elderly low-risk and younger low-risk patients with favorable genetic abnormalities; and (ii) high-risk patients with adverse genetic abnormalities and a higher median age against all low-risk patients with lower median age. Elderly low-risk and younger low-risk patients showed mainly phosphoproteomic differences especially involving transcriptional regulators and cytoskeleton. When comparing high-risk and low-risk patients both proteomic and phosphoproteomic studies showed differences involving cytoskeleton and immunoregulation but also transcriptional regulation and cell division. The age-associated prognostic impact of cyclin-dependent kinases was dependent on the cellular context. The protein level of the adverse prognostic biomarker mitochondrial aldehyde dehydrogenase (ALDH2) showed a similar significant upregulation both in elderly low-risk and elderly high-risk patients. Our results suggest that molecular mechanisms associated with cellular aging influence chemoresistance of AML cells, and especially the cytoskeleton function may then influence cellular hallmarks of aging, e.g. mitosis, polarity, intracellular transport and adhesion.

The Implementation of Mass Spectrometry-Based Proteomics Workflows in Clinical Routines of Acute Myeloid Leukemia: Applicability and Perspectives

With the current reproducibility of proteome preparation workflows along with the speed and sensitivity of the mass spectrometers, the transition of the mass spectrometry (MS)-based proteomics technology from biomarker discovery to clinical implementation is under appraisal in the biomedicine community. Therefore, this technology might be implemented soon to detect well-known biomarkers in cancers and other diseases. Acute myeloid leukemia (AML) is an aggressive heterogeneous malignancy that requires intensive treatment to cure the patient. Leukemia relapse is still a major challenge even for patients who have favorable genetic abnormalities. MS-based proteomics could be of great help to both describe the proteome changes of individual patients and identify biomarkers that might encourage specific treatments or clinical strategies. Herein, we will review the advances and availability of the MS-based proteomics strategies that could already be used in clinical proteomics. However, the heterogeneity of complex diseases as AML requires consensus to recognize AML biomarkers and to establish MS-based workflows that allow their unbiased identification and quantification. Although our literature review appears promising towards the utilization of MS-based proteomics in clinical AML in a near future, major efforts are required to validate AML biomarkers and agree on clinically approved workflows.

DNA Methylation-Based Epigenetic Repression of SLC22A4 Promotes Resistance to Cytarabine in Acute Myeloid Leukemia

Reduced expression of the uptake transporter, OCTN1 (SLC22A4), has been reported as a strong predictor of poor event-free and overall survival in multiple cohorts of patients with acute myeloid leukemia (AML) receiving the cytidine nucleoside analog, cytarabine (Ara-C). To further understand the mechanistic basis of interindividual variability in the functional expression of OCTN1 in AML, we hypothesized a mechanistic connection to DNA methylation-based epigenetic repression of SLC22A4. We found increased basal SLC22A4 methylation was associated with decreased Ara-C uptake in AML cell lines. Pre-treatment with hypomethylating agents, 5-azacytidine, or decitabine, restored SLC22A4 mRNA expression, increased cellular uptake of Ara-C, and was associated with increased cellular sensitivity to Ara-C compared with vehicle-treated cells. Additionally, lower SLC22A4 methylation status was associated with distinct clinical advantages in both adult and pediatric patients with AML. These findings suggest a regulatory mechanism is involved in the interindividual variability in response to Ara-C, and provides a basis for the integration of hypomethylating agents into Ara-C-based treatment regimens.

Therapeutic Target Discovery Using High-Throughput Genetic Screens in Acute Myeloid Leukemia

The development of high-throughput gene manipulating tools such as short hairpin RNA (shRNA) and CRISPR/Cas9 libraries has enabled robust characterization of novel functional genes contributing to the pathological states of the diseases. In acute myeloid leukemia (AML), these genetic screen approaches have been used to identify effector genes with previously unknown roles in AML. These AML-related genes centralize alongside the cellular pathways mediating epigenetics, signaling transduction, transcriptional regulation, and energy metabolism. The shRNA/CRISPR genetic screens also realized an array of candidate genes amenable to pharmaceutical targeting. This review aims to summarize genes, mechanisms, and potential therapeutic strategies found via high-throughput genetic screens in AML. We also discuss the potential of these findings to instruct novel AML therapies for combating drug resistance in this genetically heterogeneous disease.

The global burden and attributable risk factor analysis of acute myeloid leukemia in 195 countries and territories from 1990 to 2017: estimates based on the global burden of disease study 2017

BACKGROUND

Acute myeloid leukemia (AML) is a common leukemia subtype and has a poor prognosis. The risk of AML is highly related to age. In the context of population aging, a comprehensive report presenting epidemiological trends of AML is evaluable for policy-marker to allocate healthy resources.

METHODS

This study was based on the Global Burden of Disease 2017 database. We analyzed the change trends of incidence rate, death rate, and disability-adjusted life year (DALY) rate by calculating the corresponding estimated annual percentage change (EAPC) values. Besides, we investigated the influence of social development degree on AML's epidemiological trends and potential risk factors for AML-related mortality.

RESULTS

From 1990 to 2017, the incidence of AML gradually increased in the globe. Males and elder people had a higher possibility to develop AML. Developed countries tended to have higher age-standardized incidence rate and death rate than developing regions. Smoking, high body mass index, occupational exposure to benzene, and formaldehyde were the main risk factors for AML-related mortality. Notably, the contribution ratio of exposure to carcinogens was significantly increased in the low social-demographic index (SDI) region than in the high SDI region.

CONCLUSION

Generally, the burden of AML became heavier during the past 28 years which might need more health resources to resolve this population aging-associated problem. In the present stage, developed countries with high SDI had the most AML incidences and deaths. At the same time, developing countries with middle- or low-middle SDI also need to take actions to relieve rapidly increased AML burden.

Increased circulating vascular endothelial growth factor in acute myeloid leukemia patients: a systematic review and meta-analysis

BACKGROUND

Vascular endothelial growth factor (VEGF) is one of the angiogenesis regulators, which plays an important role in tumor angiogenesis and tumor progression. Current studies have found that VEGF plays an important role in hematologic diseases including acute myeloid leukemia (AML). However, the circulating levels of VEGF in AML were still controversial among published studies.

METHODS

Three databases including PubMed, EMBASE, and Cochrane Library databases were searched up to February 2020. All articles included in the meta-analysis met our inclusion and exclusion criteria. Studies will be screened and data extracted by two independent investigators. The Newcastle-Ottawa Scale (NOS) and the Risk of Bias In Non-randomized Studies of Interventions (ROBINS-I) tool were applied to evaluate the quality of the included studies. A random-effects model was applied to pool the standardized mean difference (SMD). Heterogeneity test was performed by the Q statistic and quantified using I². All statistical analysis was conducted in Stata 12.0 software.

RESULTS

Fourteen case-control studies were finally included in this systematic review and meta-analysis. Heterogeneity was high in our included studies (I² = 91.1%, P < 0.001). Sensitivity analysis showed no significant change when any one study was excluded using random-effect methods (P > 0.05). Egger's linear regression test showed that no publication bias existed (P > 0.05). Patients with AML, mainly those newly diagnosed and untreated, have higher VEGF levels (SMD = 0.85, 95% CI 0.28-1.42). Moreover, AML patients in n ≥ 40 group, plasma group, Asia and Africa group, and age ≥ 45 group had higher circulating VEGF levels (all P < 0.05).

CONCLUSIONS

Compared to healthy controls, our meta-analysis shows a significantly higher level of circulating VEGF in AML patients, and it is associated with sample size, sample type, region, and age.

Functional Classification of TP53 Mutations in Acute Myeloid Leukemia

Mutations of the TP53 gene occur in a subset of patients with acute myeloid leukemia (AML) and confer an exceedingly adverse prognosis. However, whether different types of TP53 mutations exert a uniformly poor outcome has not been investigated yet. Here, we addressed this issue by analyzing data of 1537 patients intensively treated within protocols of the German-Austrian AML study group. We classified TP53 mutations depending on their impact on protein structure and according to the evolutionary action (EAp53) score and the relative fitness score (RFS). In 98/1537 (6.4%) patients, 108 TP53 mutations were detected. While the discrimination depending on the protein structure and the EAp53 score did not show a survival difference, patients with low-risk and high-risk AML-specific RFS showed a different overall survival (OS; median, 12.9 versus 5.5 months, p = 0.017) and event-free survival (EFS; median, 7.3 versus 5.2 months, p = 0.054). In multivariable analyses adjusting for age, gender, white blood cell count, cytogenetic risk, type of AML, and TP53 variant allele frequency, these differences were statistically significant for both OS (HR, 2.14; 95% CI, 1.15-4.0; p = 0.017) and EFS (HR, 1.97; 95% CI, 1.06-3.69; p = 0.033). We conclude that the AML-specific RFS is of prognostic value in patients with TP53-mutated AML and a useful tool for therapeutic decision-making.