Isocitrate dehydrogenase 2 mutations correlate with leukemic transformation and are predicted by 2-hydroxyglutarate in myelodysplastic syndromes

Analysis of gene mutation characteristics and its correlation with prognosis in patients with myelodysplastic syndromes

Gene mutations are a pivotal component of the pathogenesis of MDS, and they hold profound prognostic significance for predicting treatment responses and survival outcomes. However, reports about mutation patterns in Chinese MDS patients are limited. In this study, we analyzed the genetic mutation of 23 genes in 231 patients with MDS using next-generation sequencing (NGS) technology, and explored the characteristics of gene mutations in MDS patients and their associations with clinical outcomes, survival, and transformation outcomes. Our results showed that 68.83% patients had at least one gene mutation, and the most common mutations were ASXL1 (21.65%), SF3B1 (17.32%), U2AF1 (16.02%), TET2 (14.72%) and TP53 (8.66%). We also showed that the genetic mutations of TP53, U2AF1 and DNMT3A are independent risk factors for death in patients with MDS, and the ETV6 gene mutation was an independent risk factor for the transformation of MDS patients to AML through the univariate and multivariate Cox regression analysis model. Additionally, the study developed a risk score based on gene mutation data that demonstrated robust predictive capability and stability for the overall survival of MDS patients. Our research provided a strong theoretical basis for the establishment of personalized treatment and prognostic risk assessment models for Chinese MDS patients.

The Genetic Landscape of Myelodysplastic Neoplasm Progression to Acute Myeloid Leukemia

Myelodysplastic neoplasm (MDS) represents a heterogeneous group of myeloid disorders that originate from the hematopoietic stem and progenitor cells that lead to the development of clonal hematopoiesis. MDS was characterized by an increased risk of transformation into acute myeloid leukemia (AML). In recent years, with the aid of next-generation sequencing (NGS), an increasing number of molecular aberrations were discovered, such as recurrent mutations in FLT3, NPM1, DNMT3A, TP53, NRAS, and RUNX1 genes. During MDS progression to leukemia, the order of gene mutation acquisition is not random and is important when considering the prognostic impact. Moreover, the co-occurrence of certain gene mutations is not random; some of the combinations of gene mutations seem to have a high frequency (ASXL1 and U2AF1), while the co-occurrence of mutations in splicing factor genes is rarely observed. Recent progress in the understanding of molecular events has led to MDS transformation into AML and unraveling the genetic signature has paved the way for developing novel targeted and personalized treatments. This article reviews the genetic abnormalities that increase the risk of MDS transformation to AML, and the impact of genetic changes on evolution. Selected therapies for MDS and MDS progression to AML are also discussed.

IDH2: A novel biomarker for environmental exposure in blood circulatory system disorders (Review)

As the risk of harmful environmental exposure is increasing, it is important to find suitable targets for the diagnosis and treatment of the diseases caused. Isocitrate dehydrogenase 2 (IDH2) is an enzyme located in the mitochondria; it plays an important role in numerous cell processes, including maintaining redox homeostasis, participating in the tricarboxylic acid cycle and indirectly taking part in the transmission of the oxidative respiratory chain. IDH2 mutations promote progression in acute myeloid leukemia, glioma and other diseases. The present review mainly summarizes the role and mechanism of IDH2 with regard to the biological effects, such as the mitophagy and apoptosis of animal or human cells, caused by environmental pollution such as radiation, heavy metals and other environmental exposure factors. The possible mechanisms of these biological effects are described in terms of IDH2 expression, reduced nicotine adenine dinucleotide phosphate content and reactive oxygen species level, among other variables. The impact of environmental pollution on human health is increasingly attracting attention. IDH2 may therefore become useful as a potential diagnostic and therapeutic target for environmental exposure-induced diseases.

The Prognostic Value of Pretherapy Peripheral Blood Inflammatory Indices in Myelodysplastic Syndromes

Background

Inflammation appears to have a critical role in carcinogenesis tumor growth according to emerging research. The platelet-to-lymphocyte ratio (PLR), neutrophil-to-lymphocyte ratio (NLR), and plasma C-reactive protein (CRP) are considered to reflect the systemic inflammatory response and clinical prognosis. The prognostic value of inflammatory indices in myelodysplastic syndrome (MDS) patients remains unclear.

Methods

A total of 213 MDS patients were enrolled for the study. Univariate and multivariate analyses were performed to determine the prognostic significance of various indicators, including PLR, NLR, and CRP.

Results

MDS patients with higher PLR, NLR, and CRP levels had significantly shorter overall survival (OS). Based on univariate analysis, age (≥60 years), gender (men), lower hemoglobin level (<10 g/dl), higher bone marrow blast percentage (>5%), poorer karyotype, and higher Revised International Prognostic Scoring System (IPSS-R) score were significantly associated with shorter OS. Patients with higher CRP levels had shorter leukemia-free survival (LFS, P = 0.041). However, higher PLR and NLR had no significant influence on LFS (P > 0.05). Multivariate Cox proportional hazards regression analysis indicated that high PLR and CRP were also independent adverse prognostic factors for OS in MDS.

Conclusions

Elevated PLR and CRP predict poor prognosis independent of the IPSS-R and provide a novel evaluation factor for MDS patients.

Comprehensive analysis of genetic factors predicting overall survival in Myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a group of clonal hematological disease with high risk of progression to AML. Accurate risk stratification is of importance for the proper management of MDS. Genetic lesions (Cytogenetic and Molecular mutations) are known to help in prognosticating the MDS patients. We have studied 152 MDS patients using cytogenetics and next generation sequencing (NGS). These patients were evaluated and as per cytogenetic prognostic group, majority (92.1%) of the patients classified as good (81.6%) and intermediate (10.5%) group. The NGS identified 38 different gene mutations in our cohort. Among 111 MDS patients with mutations, the most frequent mutated genes were SF3B1 (25.2%), SRSF2 (19%) U2AF1 (14.4%) ASXL1 (9.9%) RUNX1 (9.9%) TET2 (9%), TP53 (9%), ATM (6.3%), NRAS (5.4%) and JAK2/3 (5.4%). The survival analysis revealed that the mutations in TP53, JAK2/3, KRAS, NRAS and ASXL1 were significantly (P < 0.05) associated with poor survival of the patients. The univariate cox and multivariate cox analysis of our study suggested that the age, marrow morphology, cytogenetic and gene mutations with IPSS-R should be considered for prognosticating the MDS patients. We have proposed M-IPSS-R which changed the risk stratification i.e. 66.3% patients had decreased risk whereas 33.75% showed increased risk compared to IPSS-R. The survival analysis also showed that the M-IPSS-R were more significant in separating the patients as per their risk than the IPSS-R alone. The change in risk stratification could help in proper strategy for the treatment planning.

Decreased serum apolipoprotein A1 level predicts poor prognosis of patients with de novo myelodysplastic syndromes

BACKGROUND

Myelodysplastic syndromes (MDS) is a group of heterogeneous myeloid clonal diseases originating from hematopoietic stem cells. It has been demonstrated that apolipoproteins A1(ApoA1) are associated with disease risk in many cancer types. However, there still lacks evidence regarding the link between ApoA1 and MDS. This study was designed to investigate the prognostic value of pretreatment ApoA1 levels in MDS patients.

METHODS

We retrospectively analyzed a cohort of 228 MDS patients to explore the prognostic value of the serum ApoA1 levels at diagnosis. Patients were divided into the high ApoA1 group and the low ApoA1 group. The prognostic significance was determined by univariate and multivariate Cox hazard models.

RESULTS

MDS patients with low ApoA1 levels had significantly shorter overall survival (OS, P < 0.0001) along with a higher frequency of TP53 mutation (P = 0.002). Based on univariate analysis, age (≥ 60 years), gender (male), lower levels of hemoglobin (< 10 g/dl), HDL (≤0.91 mmol/L), higher bone marrow blast percentage (> 5%), higher IPSS-R scores and poorer karyotype were significantly associated with decreased OS. However, low ApoA1 level did not influence leukemia-free survival (LFS, P = 0.367). Multivariate Cox proportional hazards regression analysis indicated that low ApoA1 level (≤ 1.02 g/L) was also an independent adverse prognostic factor for OS in MDS (P = 0.034).

CONCLUSIONS

Decreased ApoA1 level predicts a poor prognosis of MDS patients and thus provides a novel evaluation factor for them that is independent of the IPSS-R system.

Molecular Targeted Therapy and Immunotherapy for Myelodysplastic Syndrome

Myelodysplastic syndrome (MDS) is a heterogeneous, clonal hematological disorder characterized by ineffective hematopoiesis, cytopenia, morphologic dysplasia, and predisposition to acute myeloid leukemia (AML). Stem cell genomic instability, microenvironmental aberrations, and somatic mutations contribute to leukemic transformation. The hypomethylating agents (HMAs), azacitidine and decitabine are the standard of care for patients with higher-risk MDS. Although these agents induce responses in up to 40-60% of patients, primary or secondary drug resistance is relatively common. To improve the treatment outcome, combinational therapies comprising HMA with targeted therapy or immunotherapy are being evaluated and are under continuous development. This review provides a comprehensive update of the molecular pathogenesis and immune-dysregulations involved in MDS, mechanisms of resistance to HMA, and strategies to overcome HMA resistance.

Chromatographic methods coupled to mass spectrometry for the determination of oncometabolites in biological samples-A review

It is now well-established that dysregulation of the tricarboxylic acid (TCA) cycle enzymes succinate dehydrogenase, fumarate hydratase, and isocitrate dehydrogenase leads to the abnormal cellular accumulation of succinate, fumarate, and 2-hydroxyglutarate, respectively, which contribute to the formation and malignant progression of numerous types of cancers. Thus, these metabolites, called oncometabolites, could potentially be useful as tumour-specific biomarkers and as therapeutic targets. For this reason, the development of analytical methodologies for the accurate identification and determination of their levels in biological matrices is an important task in the field of cancer research. Currently, hyphenated gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) techniques are the most powerful analytical tools in what concerns high sensitivity and selectivity to achieve such difficult task. In this review, we first provide a brief description of the biological formation of oncometabolites and their oncogenic properties, and then we present an overview and critical assessment of the GC-MS and LC-MS based analytical approaches that are reported in the literature for the determination of oncometabolites in biological samples, such as biofluids, cells, and tissues. Advantages and drawbacks of these approaches will be comparatively discussed. We believe that the present review represents the first attempt to summarize the applications of these hyphenated techniques in the context of oncometabolite analysis, which may be useful to new and existing researchers in this field.

Isocitrate Dehydrogenase 2 Inhibitors for the Treatment of Hematologic Malignancies: Advances and Future Opportunities

Tumor cells frequently reprogram cellular metabolism from oxidative phosphorylation to glycolysis. Isocitrate dehydrogenase 2 (IDH2) has been intensively studied due to its involvement in the metabolic activity of cancer cells. Mutations in IDH2 promote neomorphic activity through the generation of oncometabolite 2-hydroxyglutarate (2-HG). The overproduced 2-HG can competitively inhibit α-KG-dependent dioxygenases to trigger cell differentiation disorders, a major cause of blood tumors. This review outlines recent progress in the identification of IDH2 inhibitors in blood cancer to provide a reference for ongoing and future clinical studies.

Elevated mature monocytes in bone marrow accompanied with a higher IPSS-R score predicts a poor prognosis in myelodysplastic syndromes

BACKGROUND

Myelodysplastic syndromes (MDS) is a group of heterogeneous myeloid clonal diseases originating from hematopoietic stem cells. Clinically, elevated mature monocyte in bone marrow is often observed, but its clinical value still remains unclear.

METHODS

We retrospectively analyzed a cohort of 216 MDS patients to explore the prognostic value of the percentage of mature monocyte in bone marrow (PMMBM). All patients were divided into elevated PMMBM group and the normal group by 6% PMMBM as the cut-off value.

RESULTS

Our results showed that PMMBM> 6% was associated with inferior overall survival (OS) (P = 0.026) along with higher-risk IPSS-R (P = 0.025) and higher frequency of IDH2 mutation (P = 0.007). Multivariate analyses showed that besides older age (> 60 years) for OS, gender (male) for OS, lower neutrophil count (< 0.8 ×  10⁹/L) for OS, higher bone marrow blast percentage (> 5%) for OS and LFS, poorer karyotype for OS, elevated PMMBM was also an independent adverse prognostic factor for OS in MDS (P < 0.0001) but not for LFS (P = 0.736).

CONCLUSIONS

These findings indicate that increased PMMBM may assists Revised International Prognostic Scoring System (IPSS-R) to predict a poor outcome and provide a novel evaluation factor for MDS patients especially when their karyotype analyses fail.

Lower-dose decitabine improves clinical response compared with best supportive care in lower-risk MDS patients: a prospective, multicenter phase 2 study

Purpose: To explore the efficacy and safety of lower-dose decitabine in patients with lower-risk MDS, a prospective multicenter phase II study was conducted to compare decitabine with the best supportive care (BSC).

Methods: Patients diagnosed with lower-risk MDS from September 2013 to August 2018 were assigned to the decitabine group or the BSC group. Decitabine (12 mg/m²/day) was administered over 1 hour/day for 5 consecutive days in a 4-week cycle. BSC, including growth factors, transfusion, thalidomide, lenalidomide, and immunosuppressive agents were given consecutively. The endpoints included the proportion of patients who achieved overall response (OR) in the first 2 or 3 courses, event-free survival (EFS), and overall survival (OS).

Results: A total of recruited 82 patients were analyzed. In the decitabine group, 65.9% (27/41) achieved OR after 2 or 3 cycles of treatment, compared with 22.0% (9/41) in the BSC group (p <0.01). Besides, 44.0% (11/25) in the decitabine group became independent of RBC/Platelets transfusion, compared with 27.8% (5/18) in the BSC group. Patients with gene mutation and treated with decitabine achieved a higher OR rate, compared with those without gene mutation [72.0% (18/25) vs 11.5% (3/26), p <0.01]. There was no significant difference in the median EFS between the decitabine and BSC groups (20.6 vs 14.3 months respectively, p = 0.665). In the decitabine group, the most significant adverse events were infections of any grades or neutropenic fever (46.3%, 19/41) and one patient (4.2%) died of acute cerebral infarction within 6 weeks of treatment.

Conclusion: Lower-dose decitabine demonstrated promising clinical response with acceptable toxicity profiles in patients with low- and intermediate 1-risk MDS. A higher response rate to decitabine was observed in patients with mutated genes. Therefore, lower-dose decitabine can be advocated for patients with low-risk MDS and mutated genes.

Structure-based design, synthesis and bioactivity evaluation of macrocyclic inhibitors of mutant isocitrate dehydrogenase 2 (IDH2) displaying activity in acute myeloid leukemia cells

The enzymes involved in the metabolic pathways in cancer cells have been demonstrated as important therapeutic targets such as the isocitrate dehydrogenase 2 (IDH2). A series of macrocyclic derivatives was designed based on the marketed IDH2 inhibitor AG-221 by using the conformational restriction strategy. The resulted compounds showed moderate to good inhibitory potential against different IDH2-mutant enzymes. Amongst, compound C6 exhibited better IDH2^R140Q inhibitory potency than AG-221, and showed excellent activity of 2-hydroxyglutarate (2-HG) suppression in vitro and its mesylate displayed good pharmacokinetic profiles. Moreover, C6 performed strong binding mode to IDH2^R140Q after computational docking and dynamic simulation, which may serve as a good starting point for further development.

A continuous-time Markov model approach for modeling myelodysplastic syndromes progression from cross-sectional data

The integration of both genomics and clinical data to model disease progression is now possible, thanks to the increasing availability of molecular patients' profiles. This may lead to the definition of novel decision support tools, able to tailor therapeutic interventions on the basis of a "precise" patients' risk stratification, given their health status evolution. However, longitudinal analysis requires long-term data collection and curation, which can be time demanding, expensive and sometimes unfeasible. Here we present a clinical decision support framework that combines the simulation of disease progression from cross-sectional data with a Markov model that exploits continuous-time transition probabilities derived from Cox regression. Trajectories between patients at different disease stages are stochastically built according to a measure of patient similarity, computed with a matrix tri-factorization technique. Such trajectories are seen as realizations drawn from the stochastic process driving the transitions between the disease stages. Eventually, Markov models applied to the resulting longitudinal dataset highlight potentially relevant clinical information. We applied our method to cross-sectional genomic and clinical data from a cohort of Myelodysplastic syndromes (MDS) patients. MDS are heterogeneous clonal hematopoietic disorders whose patients are characterized by different risks of Acute Myeloid Leukemia (AML) development, defined by an international score. We computed patients' trajectories across increasing and subsequent levels of risk of developing AML, and we applied a Cox model to the simulated longitudinal dataset to assess whether genomic characteristics could be associated with a higher or lower probability of disease progression. We then used the learned parameters of such Cox model to calculate the transition probabilities of a continuous-time Markov model that describes the patients' evolution across stages. Our results are in most cases confirmed by previous studies, thus demonstrating that simulated longitudinal data represent a valuable resource to investigate disease progression of MDS patients.

Mutation status and burden can improve prognostic prediction of patients with lower-risk myelodysplastic syndromes

Patients with lower‐risk myelodysplastic syndromes (LR‐MDS) as defined by the International Prognostic Scoring System (IPSS) have more favorable prognosis in general, but significant inter‐individual heterogeneity exists. In this study, we examined the molecular profile of 15 MDS‐relevant genes in 159 patients with LR‐MDS using next‐generation sequencing. In univariate COX regression, shorter overall survival (OS) was associated with mutation status of ASXL1 (P = .001), RUNX1 (P = .031), EZH2 (P = .049), TP53 (P = .016), SRSF2 (P = .046), JAK2 (P = .040), and IDH2 (P = .035). We also found significantly shorter OS in patients with an adjusted TET2 variant allele frequency (VAF) ≥18% versus those with either an adjusted TET2 VAF <18% or without TET2 mutations (median: 20.4 vs 47.8 months; P = .020; HR = 2.183, 95%CI: 1.129‐4.224). After adjustment for IPSS, shorter OS was associated with mutation status of ASXL1 (P < .001; HR = 4.306, 95% CI: 2.144‐8.650), TP53 (P = .004; HR = 4.863, 95% CI: 1.662‐14.230) and JAK2 (P = .002; HR = 5.466, 95%CI: 1.848‐16.169), as well as adjusted TET2 VAF ≥18% (P = .008; HR = 2.492, 95% CI: 1.273‐4.876). Also, OS was increasingly shorter as the number of mutational factors increased (P < .001). A novel prognostic scoring system incorporating the presence/absence of the four independent mutational factors into the IPSS further stratified LR‐MDS patients into three prognostically different groups (P < .001). The newly developed scoring system redefined 10.1% (16/159) of patients as a higher‐risk group, who could not be predicted by the currently prognostic models. In conclusion, integration of the IPSS with mutation status/burden of certain MDS‐relevant genes may improve the prognostication of patients with LR‐MDS and could help identify those with worse‐than‐expected prognosis for more aggressive treatment.

Treatment of myelodysplastic syndrome in the era of next-generation sequencing

Next-generation sequencing (NGS) is rapidly changing the clinical care of patients with myelodysplastic syndrome (MDS). NGS can be used for various applications: (i) in the diagnostic process to discriminate between MDS and other diseases such as aplastic anaemia, myeloproliferative disorders and idiopathic cytopenias; (ii) for classification, for example, where the presence of SF3B1 mutation is one criterion for the ring sideroblast anaemia subgroups in the World Health Organization 2016 classification; (iii) for identification of patients suitable for targeted therapy (e.g. IDH1/2 inhibitors); (iv) for prognostication, for example, where specific mutations (e.g. TP53 and RUNX1) are associated with inferior prognosis, whereas others (e.g. SF3B1) are associated with superior prognosis; and (v) to monitor patients for progression or treatment failure. Most commonly, targeted sequencing for genes (normally 50-100 genes) reported to be recurrently mutated in myeloid disease is used. At present, NGS is rarely incorporated into clinical guidelines although an increasing number of studies have demonstrated the benefit of using NGS in the clinical management of MDS patients.

mTORC1 as a Regulator of Mitochondrial Functions and a Therapeutic Target in Cancer

Continuous proliferation of tumor cells requires constant adaptations of energy metabolism to rapidly fuel cell growth and division. This energetic adaptation often comprises deregulated glucose uptake and lactate production in the presence of oxygen, a process known as the "Warburg effect." For many years it was thought that the Warburg effect was a result of mitochondrial damage, however, unlike this proposal tumor cell mitochondria maintain their functionality, and is essential for integrating a variety of signals and adapting the metabolic activity of the tumor cell. The mammalian/mechanistic target of rapamycin complex 1 (mTORC1) is a master regulator of numerous cellular processes implicated in proliferation, metabolism, and cell growth. mTORC1 controls cellular metabolism mainly by regulating the translation and transcription of metabolic genes, such as peroxisome proliferator activated receptor γ coactivator-1 α (PGC-1α), sterol regulatory element-binding protein 1/2 (SREBP1/2), and hypoxia inducible factor-1 α (HIF-1α). Interestingly it has been shown that mTORC1 regulates mitochondrial metabolism, thus representing an important regulator in mitochondrial function. Here we present an overview on the role of mTORC1 in the regulation of mitochondrial functions in cancer, considering new evidences showing that mTORC1 regulates the translation of nucleus-encoded mitochondrial mRNAs that result in an increased ATP mitochondrial production. Moreover, we discuss the relationship between mTORC1 and glutaminolysis, as well as mitochondrial metabolites. In addition, mitochondrial fission processes regulated by mTORC1 and its impact on cancer are discussed. Finally, we also review the therapeutic efficacy of mTORC1 inhibitors in cancer treatments, considering its use in combination with other drugs, with particular focus on cellular metabolism inhibitors, that could help improve their anti neoplastic effect and eliminate cancer cells in patients.