Chromosomal Instability in Acute Myeloid Leukemia

Targeting chromosomal instability in patients with cancer

Chromosomal instability (CIN) is a hallmark of cancer and a driver of metastatic dissemination, therapeutic resistance, and immune evasion. CIN is present in 60-80% of human cancers and poses a formidable therapeutic challenge as evidenced by the lack of clinically approved drugs that directly target CIN. This limitation in part reflects a lack of well-defined druggable targets as well as a dearth of tractable biomarkers enabling direct assessment and quantification of CIN in patients with cancer. Over the past decade, however, our understanding of the cellular mechanisms and consequences of CIN has greatly expanded, revealing novel therapeutic strategies for the treatment of chromosomally unstable tumours as well as new methods of assessing the dynamic nature of chromosome segregation errors that define CIN. In this Review, we describe advances that have shaped our understanding of CIN from a translational perspective, highlighting both challenges and opportunities in the development of therapeutic interventions for patients with chromosomally unstable cancers.

Transforming growth factor-β1 and vascular endothelial growth factor levels in senile acute myeloid leukemia and correlation with prognosis

BACKGROUND

Acute myeloid leukemia (AML) is a disease in which immature hematopoietic cells accumulate in the bone marrow and continuously expand, inhibiting hematopoiesis. The treatment and prognosis of this disease have always been unsatisfactory.

AIM

To investigate the correlation between vascular endothelial growth factor (VEGF) and transforming growth factor-β1 (TGFβ1) expression and prognosis in older adults with AML.

METHODS

This study enrolled 80 patients with AML (AML group), including 36 with complete response (AML-CR), 23 with partial response (AML-PR), and 21 with no response (AML-NR). The expression levels of VEGF and TGFβ1 were detected by reverse transcription polymerase chain reaction in bone marrow mononuclear cells isolated from 56 healthy controls. Kaplan-Meier analysis was performed to assess overall survival (OS) and progression- or disease-free survival (DFS). Prognostic risk factors were analyzed using a Cox proportional hazards model.

RESULTS

The AML group showed a VEGF level of 2.68 ± 0.16. VEGF expression was lower in patients with AML-CR than those with AML-PR or AML-NR (P < 0.05). TGFβ1 expression in the AML group was 0.33 ± 0.05. Patients with AML-CR showed a higher TGFβ1 expression than those with AML-PR or AML-NR (P < 0.05). VEGF and TGFβ1 expression in patients with AML was significantly correlated with the counts of leukocytes, platelets, hemoglobin, and peripheral blood immature cells (P < 0.05); Kaplan-Meier survival analysis revealed that patients with high TGFβ1 expression had better OS and DFS than those with low TGFβ1 expression (P < 0.05), whereas patients with low VEGF levels showed better OS and DFS than those with high VEGF levels (P < 0.05). VEGF, TGFβ1, and platelet count were identified by the Cox proportional hazards model as independent risk factors for OS (P < 0.05), while VEGF, TGFβ1, and white blood cell count were independent risk factors for DFS (P < 0.05).

CONCLUSION

Decreased VEGF expression and increased TGFβ1 expression in patients with AML provide valuable references for determining and individualizing clinical treatment strategies.

Comprehensive insights into AML relapse: genetic mutations, clonal evolution, and clinical outcomes

INTRODUCTION

Acute myeloid leukemia (AML) is a complex hematologic malignancy characterized by uncontrolled proliferation of myeloid precursor cells within bone marrow. Despite advances in understanding of its molecular underpinnings, AML remains a therapeutic challenge due to its high relapse rate and clonal evolution.

METHODS

In this retrospective study, we analyzed data from 24 AML patients diagnosed at a single institution between January 2017 and August 2023. Comprehensive genetic analyses, including chromosomal karyotyping, next-generation sequencing, and gene fusion assays, were performed on bone marrow samples obtained at initial diagnosis and relapse. Clinical data, treatment regimens, and patient outcomes were also documented.

RESULTS

Mutations in core genes of FLT3, NPM1, DNMT3A, and IDH2 were frequently discovered in diagnostic sample and remained in relapse sample. FLT3-ITD, TP53, KIT, RUNX1, and WT1 mutation were acquired at relapse in one patient each. Gene fusion assays revealed stable patterns, while chromosomal karyotype analyses indicated a greater diversity of mutations in relapsed patients. Clonal evolution patterns varied, with some cases showing linear or branching evolution and others exhibiting no substantial change in core mutations between diagnosis and relapse.

CONCLUSIONS

Our study integrates karyotype, gene rearrangements, and gene mutation results to provide a further understanding of AML heterogeneity and evolution. We demonstrate the clinical relevance of specific mutations and clonal evolution patterns, emphasizing the need for personalized therapies and measurable residual disease monitoring in AML management. By bridging the gap between genetics and clinical outcome, we move closer to tailored AML therapies and improved patient prognoses.

Genetically predicted telomere length and the risk of 11 hematological diseases: a Mendelian randomization study

OBJECTIVE

Previous studies have demonstrated that various hematologic diseases (HDs) induce alterations in telomere length (TL). The aim of this study is to investigate whether genetically predicted changes in TL have an impact on the risk of developing HDs.

METHODS

GWAS data for TL and 11 HDs were extracted from the database. The R software package "TwoSampleMR" was employed to conduct a two-sample Mendelian randomization (MR) analysis, in order to estimate the influence of TL changes on the risk of developing the 11 HDs.

RESULTS

We examined the effect of TL changes on the risk of developing the 11 HDs. The IVW results revealed a significant causal association between genetically predicted longer TL and the risk of developing acute lymphocytic leukemia (ALL), acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MANTLE), and hodgkin lymphoma (HODGKIN). However, there was no significant causal relationship observed between TL changes and the risk of developing chronic myeloid leukemia (CML), diffuse large b-cell lymphoma (DLBCL), marginal zone b-cell lymphoma (MARGINAL), follicular lymphoma (FOLLICULAR), monocytic leukemia (MONOCYTIC), and mature T/NK-cell lymphomas (TNK).

CONCLUSIONS

The MR analysis revealed a positive association between genetically predicted longer TL and an increased risk of developing ALL, AML, CLL, MANTLE, and HODGKIN. This study further supports the notion that cells with longer TL have greater proliferative and mutational potential, leading to an increased risk of certain HDs.

Evaluating Chromosome Instability and Genotoxicity Through Single Cell Quantitative Imaging Microscopy

Across eukaryotes, genome stability is essential for normal cell function, physiology, and species survival. Aberrant expression of key genes or exposure to genotoxic agents can have detrimental effects on genome stability and contribute to the development of various diseases, including cancer. Chromosome instability (CIN), or ongoing changes in chromosome complements, is a frequent form of genome instability observed in cancer and is a driver of genetic and cell-to-cell heterogeneity that can be rapidly detected and quantitatively assessed using surrogate markers of CIN. For example, single cell quantitative imaging microscopy (QuantIM) can be used to simultaneously identify changes in nuclear areas and micronucleus formation. While changes in nuclear areas are often associated with large-scale changes in chromosome complements (i.e., ploidy), micronuclei are small extra-nuclear bodies found outside the primary nucleus that have previously been employed as a measure of genotoxicity of test compounds. Here, we present a facile QuantIM approach that allows for the rapid assessment and quantification of CIN associated phenotypes and genotoxicity. First, we provide protocols to optimize and execute CIN and genotoxicity assays. Secondly, we present the critical imaging settings, optimization steps, downstream statistical analyses, and data visualization strategies employed to obtain high quality and robust data. These approaches can be easily applied to assess the prevalence of CIN associated phenotypes and genotoxic stress for a myriad of experimental and clinical contexts ranging from direct tests to large-scale screens of various genetic contexts (i.e., aberrant gene expression) or chemical compounds. In summary, this QuantIM approach facilitates the identification of novel CIN genes and/or genotoxic agents that will provide greater insight into the aberrant genes and pathways underlying CIN and genotoxicity.

Rare Ring Chromosome [r(15)]: Cytogenetic Abnormality in TP53-Mutated De Novo AML-M4 Masked as Gastrointestinal Bleed With Rapidly Progressing Hyperleukocytosis and Leukostasis

TP53-mutated (TP53m) acute myeloid leukemia (AML) comprises only 5-15% of de novo AML, associated with poor survival outcomes due to its resistance to conventional therapy. Ring chromosomes, an even more rare subset of genetic anomalies, occur in only 2% of cases. We report a unique case of de novo AML with both TP53 and ring chromosome anomalies leading to a catastrophic outcome in a 72-year-old male who initially presented with gastrointestinal bleeding (GIB) and urethral stone status post-cystoscopy with J-stent placement. He had no history of chemotherapy use, radiation, benzene exposure, or any other risk factors except for his age. He was noted to have pancytopenia, for which bone marrow biopsy, flow cytometry, and cytogenetic studies were done. Biopsy reported an interesting next-generation sequenced TP53-mutated AML, which correlates with a low rate of response to standard chemotherapy except for bone marrow transplants. Notably, with a complex aberration of 45 XY with multiple translocations (t), deletions (del), inversions (inv), derivative (der) breakpoints, aneuploidy, and rare ring and maker chromosomes, his case was complicated with rapid-onset and very severe hyperleucostasis, reflecting the prognostic value of this rare cytogenetic configuration. The patient expired within 48 hours of diagnosis, despite the urgent initiation of cytoreductive therapy and the mitigation of tumor lysis syndrome with Rasburicase. To the best of our knowledge, this is one of the first AML-M4 patients with rapid-onset leucostasis and the demise of next-generation sequences (NGS) in a de Novo AML patient with this rare complex combination.

Investigating the Expression Pattern of the SETMAR Gene Transcript Variants in Childhood Acute Leukemia: Revisiting an Old Gene

BACKGROUND

The chimeric enzyme SETMAR (or Metnase) has been associated with several DNA processes, including DNA damage repair through the non-homologous joining pathway and suppression of chromosomal translocation in mouse fibroblasts. SETMAR overexpression has been reported in certain cancers suggesting that it might contribute to the establishment or progression of these cancers. In leukemia, the SETMAR gene transcript variants have not been widely studied. Therefore, this study aimed to quantify 3 predominant SETMAR variants in 2 types of childhood acute leukemia, acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL).

METHODS

In this study, using reverse transcription-quantitative polymerase chain reaction (RT-qPCR), the relative expression of 3 SETMAR transcript variants (Var 1, Var 2, and Var A) were evaluated in the bone marrow samples collected from 30 newly diagnosed patients with AML, 65 newly diagnosed patients with ALL, and 15 healthy individuals.

RESULTS

The expression of SETMAR variants 1 and A were significantly higher in AML patients compared with controls ( P =0.02, and P =0.009, respectively). Variant A expression was significantly higher in ALL compared with controls ( P =0.003). When comparing the expression in translocation-positive and negative subgroups, the expression of variant 1 was significantly higher in translocation-positive ALL patients ( P =0.03). The variants' distribution patterns differed concerning translocation status ( P =0.041), as variants 1 and A were dominant in the translocation-positive ALL group, and variant 2 was more prevalent in translocation-negative ones.

CONCLUSIONS

According to the results, SETMAR showed increased expression in pediatric acute leukemia's bone marrow samples, indicating a role for this molecule in leukemia pathogenesis. As this is the first report of SETMAR expression in pediatric leukemias, further studies are needed to investigate the causality of this association.

Long non-coding RNAs regulate treatment outcome in leukemia: What have we learnt recently?

Leukemia is a group of highly heterogeneous and life-threatening blood cancers that originate from abnormal hematopoietic stem cells. Multiple treatments are approved for leukemia, including chemotherapy, targeted therapy, hematopoietic stem cell transplantation, radiation therapy, and immunotherapy. Unfortunately, therapeutic resistance occurs in a substantial proportion of patients and greatly compromises the treatment efficacy of leukemia, resulting in relapse and mortality. The abnormal activity of receptor tyrosine kinases, cell membrane transporters, intracellular signal transducers, transcription factors, and anti-apoptotic proteins have been shown to contribute to the emergence of therapeutic resistance. Despite these findings, the exact mechanisms of treatment resistance are still not fully understood, which limits the development of effective measures to overcome it. Long non-coding RNAs (lncRNA) are a class of regulatory molecules that are gaining increasing attention, and lncRNA-mediated regulation of therapeutic resistance against multiple drugs for leukemia is being revealed. These dysregulated lncRNAs not only serve as potential targets to reduce resistance but also might improve treatment response prediction and individualized treatment decision. Here, we summarize the recent findings on lncRNA-mediated regulation of therapeutic resistance in leukemia and discuss future perspectives on how to make use of the dysregulated lncRNAs in leukemia to improve treatment outcome.

Circular RNAs: pivotal role in the leukemogenesis and novel indicators for the diagnosis and prognosis of acute myeloid leukemia

Acute myeloid leukemia (AML) is an aggressive hematological malignancy and affected patients have poor overall survival (OS) rates. Circular RNAs (circRNAs) are a novel class of non-coding RNAs (ncRNAs) with a unique loop structure. In recent years, with the development of high-throughput RNA sequencing, many circRNAs have been identified exhibiting either up-regulation or down-regulation in AML patients compared with healthy controls. Recent studies have reported that circRNAs regulate leukemia cell proliferation, stemness, and apoptosis, both positively and negatively. Additionally, circRNAs could be promising biomarkers and therapeutic targets in AML. In this study, we present a comprehensive review of the regulatory roles and potentials of a number of dysregulated circRNAs in AML.

Morphological markers of chromosomal instability in bone marrow aspiration and trephine biopsy of acute leukemia and myelodysplastic syndrome

The role of chromosomal instability (CI) in oncogenesis is very well described in solid tumours, but there are a lack of studies on haematology malignancy, especially with multiple morphological markers. The study aims to analyze seven morphological markers of CI- chromatin bridges (CB), multipolar mitosis (MPM), nuclear budding (NB), micronuclei (MN), nuclear heterogeneity (NH), laggards, chromatin strings (CS) in bone marrow aspirate (BMA) and biopsy of acute leukaemia (AL), and myelodysplastic syndrome (MDS). It is a retrospective cross-sectional analytical study where BMA and biopsy were reviewed for CI markers. We compared CI markers in five categories. CI markers were further correlated with clinical manifestations and outcomes of patients. The study included 54 samples of 37 patients. Overall, the median (IQR) of markers were as follows: MN 3.5 (1,7), NB 5 (1,18), MPM 1 (0,4), CB 1(0,2), Laggards 0 (0,1), and CS 2.5 (0,6). NH was noted in 65.4% of samples. All CI markers except laggards were significantly increased in B-ALL, AML, and MDS compared to other categories. Many CI markers were significantly raised with a few clinical features. The MN, MPM, Laggard, and NH markers were significantly increased in the dead patients compared to those who survived. The study, one of the first to analyze multiple CI markers, revealed that the CI markers were significantly increased in AL and MDS patients and significantly associated with clinical manifestations and outcomes. Morphology markers of CI are valuable and cost-effective in diagnostic strategy, type of malignancies, and assessing prognosis.

Analysis of the Clinical Efficacy of Azacytidine + Venetoclax in the Treatment of Elderly Patients with Relapsed Refractory Acute Myeloid Leukemia

Objective

To explore the clinical efficacy of azacytidine + venetoclax in the treatment of elderly patients with relapsed refractory acute myeloid leukemia (AML).

Method

The present study included 20 elderly patients with relapsed refractory AML from January 2019 to January 2021. These patients were randomized into treatment groups (n = 10, azacytidine alone) and control groups (n = 10, azacytidine + venetoclax) by a random number table. The differences in efficacy, adverse reactions, hematology parameters, and immune functions in elderly patients with relapsed refractory AML in two groups were analyzed.

Results

The total efficiency for elderly patients with relapsed refractory AML was 90.00% and significantly higher than that in the control group (40.00%), P < 0.05; PLT and WBC after treatment in the treatment group were significantly higher than those in the control group, and Hb was significantly lower than in the control group, P < 0.05; CD4+, CD3+, and CD4+/CD8+ after treatment in both groups were significantly lower than those before treatment, P < 0.05; CD4+, CD3+, and CD4+/CD8+ after treatment were not significantly different between the two groups, P > 0.05; the incidences of adverse reactions were not significantly different between the two groups, P > 0.05.

Conclusion

Azacytidine + venetoclax in the treatment of elderly patients with relapsed refractory AML could improve efficacy and hematology parameters with high safety, which is of great significance.

Expression and prognostic significance of chromatin modulators EHMT2/G9a and KDM2b in acute myeloid leukemia

Epigenetics factors are critical for normal cell function and their regulation is sensitive to malignancy development. EHMT2/G9a and KDM2b are key epigenetics players in different cancer types. However, their expression profiles and related consequences in acute myeloid leukemia (AML) patients have not been known yet. In addition to routine lab work, expression levels of EHMT2/G9a and KDM2b were determined in 110 adult and pediatric patients with De Novo AML. Relations between their expression and patients' clinical data were tested by statistical methods. EHMT2/G9a and KDM2b were highly expressed in AML patients against control cases and associated with the presence of adverse genomic alterations. In response to induction chemotherapy, EHMT2/G9a and KDM2b showed to be significantly high in resistant and relapsed patients in comparison to the complete remission group. KDM2b overexpression was associated with CD11c (integrin alpha X) downregulation. Kaplan-Meier analysis indicated that EHMT2/G9a and KDM2b overexpression was correlated with poor survival status in AML patients. We conclude that EHMT2/G9a and KDM2b expression levels could be used as independent prognostic factors for AML disease.

Case of Patient with AML with Complex Karyotype including Ultra-Rare t(4;8)(q32;q13), t(4;11)(q21;p15) and Familial Aggregation of Myeloid Malignancies

We present a unique case of a young woman with acute myeloid leukemia (AML) with complex karyotype. The presence of the t(4;11)(q23;p15) is extremely rare in myeloid leukemias, while t(4;8)(q32;q13) has not yet been described in any leukemia reference. Another interesting issue is the familial aggregation of myeloid malignancies and worse course of the disease in each subsequent generation, as well as an earlier onset of the disease. Our report emphasizes the need for thorough pedigree examination upon myeloid malignancy diagnosis as there are relatives for whom counseling, gene testing, and surveillance may be highly advisable.

Therapeutic inhibition of GAS6-AS1/YBX1/MYC axis suppresses cell propagation and disease progression of acute myeloid leukemia

BACKGROUND

Acute myeloid leukemia (AML) is the most common type of leukemia in adults. Its therapy has not significantly improved during the past four decades despite intense research efforts. New molecularly targeted therapies are in great need. The proto-oncogene c-Myc (MYC) is an attractive target due to its transactivation role in multiple signaling cascades. Deregulation of the MYC is considered one of a series of oncogenic events required for tumorigenesis. However, limited knowledge is available on which mechanism underlie MYC dysregulation and how long non-coding RNAs (lncRNAs) are involved in MYC dysregulation in AML.

METHODS

AML microarray chips and public datasets were screened to identify novel lncRNA GAS6-AS1 was dysregulated in AML. Gain or loss of functional leukemia cell models were produced, and in vitro and in vivo experiments were applied to demonstrate its leukemogenic phenotypes. Interactive network analyses were performed to define intrinsic mechanism.

RESULTS

We identified GAS6-AS1 was overexpressed in AML, and its aberrant function lead to more aggressive leukemia phenotypes and poorer survival outcomes. We revealed that GAS6-AS1 directly binds Y-box binding protein 1 (YBX1) to facilitate its interaction with MYC, leading to MYC transactivation and upregulation of IL1R1, RAB27B and other MYC target genes associated with leukemia progression. Further, lentiviral-based GAS6-AS1 silencing inhibited leukemia progression in vivo.

CONCLUSIONS

Our findings revealed a previously unappreciated role of GAS6-AS1 as an oncogenic lncRNA in AML progression and prognostic prediction. Importantly, we demonstrated that therapeutic targeting of the GAS6-AS1/YBX1/MYC axis inhibits AML cellular propagation and disease progression. Our insight in lncRNA associated MYC-driven leukemogenesis may contribute to develop new anti-leukemia treatment strategies.

Evaluation of Poly(ADP-ribose) Polymerase Inhibitor, Pamiparib (BGB-290) in Treating Acute Myeloid Leukemia and the Characterization of Its Nanocarrier

Despite the continuous improvement of leukemia treatment in the clinic, the overall 5-year disease-free survival of acute myeloid leukemia (AML) is only approximately 30%-60% due to relapse and the refractoriness of AML after traditional chemotherapy. Inhibition of poly(ADP-ribose) polymerase (PARP), a member of the DNA damage repair complex, has a strong antitumor effect in solid tumors. However, the role of PARP in AML remains unclear. We found that high levels of PARP1 and PARP2 were positively related to chemotherapy resistance and poor prognosis in patients with AML. Doxorubicin (DOX)-resistant AML cells highly expressed PAPR1 and PARP2. Knockdown of PARP1 and PARP2, or pharmaceutical inhibition of PARP by the PARP inhibitor (PARPi) BGB-290, significantly enhanced the cytotoxicity of DOX in AML cells due to increased DNA damage. PLGA-loading BGB-290 was properly self-assembled into stable BGB-290@PLGA nanoparticles (NPs), which is uniform particle size and good stability. BGB-290@PLGA is easily uptake by AML cell lines and stays for a long time. Combined with DOX, BGB-290@PLGA can significantly improve the chemosensitivity of AML cell lines. Furthermore, BGB-290 and DOX combination treatment dramatically repressed the onset of leukemia and prolonged the survival of THP-1 xenografted mice. Overall, this study demonstrated that PARPi with traditional chemotherapy could be an efficient therapeutic strategy for AML.

In Silico Methods for the Identification of Diagnostic and Favorable Prognostic Markers in Acute Myeloid Leukemia

Acute myeloid leukemia (AML), the most common type of acute leukemia in adults, is mainly asymptomatic at early stages and progresses/recurs rapidly and frequently. These attributes necessitate the identification of biomarkers for timely diagnosis and accurate prognosis. In this study, differential gene expression analysis was performed on large-scale transcriptomics data of AML patients versus corresponding normal tissue. Weighted gene co-expression network analysis was conducted to construct networks of co-expressed genes, and detect gene modules. Finally, hub genes were identified from selected modules by applying network-based methods. This robust and integrative bioinformatics approach revealed a set of twenty-four genes, mainly related to cell cycle and immune response, the diagnostic significance of which was subsequently compared against two independent gene expression datasets. Furthermore, based on a recent notion suggesting that molecular characteristics of a few, unusual patients with exceptionally favorable survival can provide insights for improving the outcome of individuals with more typical disease trajectories, we defined groups of long-term survivors in AML patient cohorts and compared their transcriptomes versus the general population to infer favorable prognostic signatures. These findings could have potential applications in the clinical setting, in particular, in diagnosis and prognosis of AML.