Mutant IDH: a targetable driver of leukemic phenotypes linking metabolism, epigenetics and transcriptional regulation

Characteristics and Prognosis of "Acute Promyelocytic Leukemia-like" Nucleophosmin-1-Mutated Acute Myeloid Leukemia in a Retrospective Patient Cohort

Background: AML with NPM1 mutation is the largest subcategory of AML, representing about 35% of AML cases. It is characterized by CD34 negativity, which suggests a relatively differentiated state of the bulk of leukemic blasts. Notably, a significant subset of NPM1-mutated AML cases also exhibit HLA-DR negativity, classifying them as "double-negative", and mimicking, therefore, the CD34- HLA-DR- immunophenotype of acute promyelocytic leukemia (APL). Objectives: This study focuses on the "acute promyelocytic leukemia-like" ("APL-like") subset of NPM1-mutated AML, which can be challenging to distinguish from APL at presentation, prior to confirming RARa translocations. We aim to investigate the hematologic and immunophenotypic parameters that may aid to its distinction from APL. Additionally, we explore differences in genetic profile and prognosis between "APL-like" and "non-APL-like" NPM1-mutated AML cases. Methods: We conducted a retrospective evaluation of 77 NPM1-mutated AML cases and 28 APL cases. Results: Morphological characteristics, hematologic parameters (such as DD/WBC and PT/WBC), and specific immunophenotypic markers (including SSC, CD64, and CD4) can assist in the early distinction of "APL-like" NPM1-mutated AML from APL. Regarding differences in genetic profiles and outcomes between "APL-like" and non-"APL-like" NPM1-mutated AML cases, we observed a significantly higher incidence of IDH1/2 /TET2 mutations, along with a significantly lower incidence of DNMT3A mutations in the "APL-like" subset compared to the non-"APL-like" subset. The frequency of Ras-pathway and FLT3 mutations did not differ between these last two groups, nor did their prognoses. Conclusions: Our findings contribute to a comprehensive characterization of NPM1-mutated AML, enhancing diagnostic accuracy and aiding in the detailed classification of the disease. This information may potentially guide targeted therapies or differentiation-based treatment strategies.

Discovery of Novel Dual Inhibitors Targeting Mutant IDH1 and NAMPT for the Treatment of Glioma with IDH1Mutation

The targeting of cancer cell intrinsic metabolism has emerged as a promising strategy for antitumor intervention. In the study, we identified the first-in-class small molecules that effectively inhibit both mutant isocitrate dehydrogenase 1 (mIDH1) and nicotinamide phosphoribosyltransferase (NAMPT), two crucial targets in cancer metabolism, through structure-based drug design. Notably, compound 23h exhibits excellent and balanced inhibitory activities against both mIDH1 (IC50 = 14.93 nM) and NAMPT (IC50 = 12.56 nM), leading to significant suppression of IDH1-mutated glioma cell (U87 MG-IDH1R132H) proliferation. Significantly, compound 23h has the ability to cross the blood-brain barrier (B/P ratio, 0.76) and demonstrates remarkable in vivo antitumor efficacy (20 mg/kg) in the U87 MG-IDH1R132H orthotopic transplantation mouse models without any notable toxicity. This proof-of-concept investigation substantiates the viability of discovering small molecules that concurrently target mIDH1 and NAMPT, providing valuable leads for the treatment of glioma and an efficient approach for the discovery of multitarget antitumor drugs.

Emerging DNA Methylome Targets in FLT3-ITD-Positive Acute Myeloid Leukemia: Combination Therapy with Clinically Approved FLT3 Inhibitors

OPINION STATEMENT

The internal tandem duplication (ITD) mutation of the FMS-like receptor tyrosine kinase 3 (FLT3-ITD) is the most common mutation observed in approximately 30% of acute myeloid leukemia (AML) patients. It represents poor prognosis due to continuous activation of downstream growth-promoting signaling pathways such as STAT5 and PI3K/AKT. Hence, FLT3 is considered an attractive druggable target; selective small FLT3 inhibitors (FLT3Is), such as midostaurin and quizartinib, have been clinically approved. However, patients possess generally poor remission rates and acquired resistance when FLT3I used alone. Various factors in patients could cause these adverse effects including altered epigenetic regulation, causing mainly abnormal gene expression patterns. Epigenetic modifications are required for hematopoietic stem cell (HSC) self-renewal and differentiation; however, critical driver mutations have been identified in genes controlling DNA methylation (such as DNMT3A, TET2, IDH1/2). These regulators cause leukemia pathogenesis and affect disease diagnosis and prognosis when they co-occur with FLT3-ITD mutation. Therefore, understanding the role of different epigenetic alterations in FLT3-ITD AML pathogenesis and how they modulate FLT3I's activity is important to rationalize combinational treatment approaches including FLT3Is and modulators of methylation regulators or pathways. Data from ongoing pre-clinical and clinical studies will further precisely define the potential use of epigenetic therapy together with FLT3Is especially after characterized patients' mutational status in terms of FLT3 and DNA methlome regulators.

5-methylcytosine RNA modification regulators-based patterns and features of immune microenvironment in acute myeloid leukemia

Acute myeloid leukemia (AML) is a highly heterogeneous malignant disease of the blood cell. The current therapies for AML are unsatisfactory and the molecular mechanisms underlying AML are unclear. 5-methylcytosine (m5C) is an important posttranscriptional modification of mRNA, and is involved in the regulation of mRNA stability, translation, and other aspects of RNA metabolism. However, based on our knowledge of published literature, the role of the m5C regulators has not been explored in AML till date. In this study, we clarified the expression and gene variants of m5C regulators in AML and found that most m5C regulators were differentially expressed and correlated with disease prognosis. We also found that the methylation status of certain m5C regulators (e.g., DNMT3A, DNMT3B) affects the survival of AML patients. Two m5C modification subtypes, and high- and low-risk subgroups identified based on the expression of m5C regulators showed significant differences in the prognosis as well as immune cell infiltration. In addition, most of the m5C regulators were found to be correlated with miRNA expression in AML, as well as IC50 values of many drugs. The miRNA and GSVA analysis were used to identify the different miRNAs and KEGG or hallmark pathways between high- and low-risk subgroups. We also built a prognostic model based on m5C regulators, which was validated by two GSE databases. To verify the reliability of our analysis and conclusions, qPCR was used to identify the expressions of m5C regulators between normal and AML. In summary, we comprehensively explored the molecular characteristics of m5C regulators and built a prognostic model in AML. We proposed new mechanistic insights into the role of m5C in multiple databases and clinical data, which may pave novel ways for the development of therapeutic strategies.

Single-center, observational study of AML/MDS-EB with IDH1/2 mutations: genetic profile, immunophenotypes, mutational kinetics and outcomes

OBJECTIVE

IDH1/2 mutations, intervening in epigenetic procedures, are frequently encountered in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). Knowledge of the genetics, immunophenotypes, and mutational kinetics of IDH1/2-mutated AML can contribute to the understanding of AML clonal architecture and inform therapeutics and monitoring.

METHODS

We retrospectively analyzed 50 IDH1/2-mutated AML/MDS-EB cases of our institution, to identify recurrent co-mutations, immunophenotypes, patterns of co-variance of IDH1/2 allele burdens with those of recurrent co-mutations, frequency of persistent IDH1/2 mutation as clonal hematopoiesis of indeterminate potential (CHIP) in remission and response to hypomethylating agents.

RESULTS

Most frequently co-mutated genes were DNMT3A, SRSF2 and NPM1. Most cases with co-existent IDH1/2 and NPM1 mutations (11/13) showed an 'APL-like' immunophenotype (CD34-HLADR-). Allele burdens of mutated IDH1/2 were identical to mutated SRSF2 allele burdens at diagnosis and remission, but not always to mutated NPM1 allele burden in remission. We show persistence of significant mutIDH1/2 allele burden in approximately one-fourth of patients with deep remissions. IDH1/2 mutations were significantly more frequent among responders to first-line HMA-based regimens than among non-responders, in patients treated for myeloid neoplasms with excess blasts.

CONCLUSIONS

IDH1/2 mutations are most frequently accompanied by DNMT3A, SRSF2 and NPM1 mutations. NPM1-IDH1/2 mutated AML has a mature phenotype possibly amenable to differentiation therapies. IDH1/2 and SRSF2 mutations probably arise at the same developmental stage of the disease, as their allele burdens covariate. IDH1/2 mutation represents CHIP in a substantial proportion of cases and is therefore no reliable residual disease marker. The preferential presence of IDH1/2 mutations among HMA-responders could inform therapeutic decisions if confirmed in larger series.

Gene expression model inference from snapshot RNA data using Bayesian non-parametrics

Gene expression models, which are key towards understanding cellular regulatory response, underlie observations of single-cell transcriptional dynamics. Although RNA expression data encode information on gene expression models, existing computational frameworks do not perform simultaneous Bayesian inference of gene expression models and parameters from such data. Rather, gene expression models-composed of gene states, their connectivities and associated parameters-are currently deduced by pre-specifying gene state numbers and connectivity before learning associated rate parameters. Here we propose a method to learn full distributions over gene states, state connectivities and associated rate parameters, simultaneously and self-consistently from single-molecule RNA counts. We propagate noise from fluctuating RNA counts over models by treating models themselves as random variables. We achieve this within a Bayesian non-parametric paradigm. We demonstrate our method on the Escherichia coli lacZ pathway and the Saccharomyces cerevisiae STL1 pathway, and verify its robustness on synthetic data.

The immunological role of mesenchymal stromal cells in patients with myelodysplastic syndrome

Myelodysplastic syndrome (MDS) is a common hematological malignant disease, characterized by malignant hematopoietic stem cell proliferation in the bone marrow (BM); clinically, it mainly manifests clinically mainly by as pathological hematopoiesis, hemocytopenia, and high-risk transformation to acute leukemia. Several studies have shown that the BM microenvironment plays a critical role in the progression of MDS. In this study, we specifically evaluated mesenchymal stromal cells (MSCs) that exert immunomodulatory effects in the BM microenvironment. This immunomodulatory effect occurs through direct cell-cell contact and the secretion of soluble cytokines or micro vesicles. Several researchers have compared MSCs derived from healthy donors to low-risk MDS-associated bone mesenchymal stem cells (BM-MSCs) and have found no significant abnormalities in the MDS-MSC phenotype; however, these cells have been observed to exhibit altered function, including a decline in osteoblastic function. This altered function may promote MDS progression. In patients with MDS, especially high-risk patients, MSCs in the BM microenvironment regulate immune cell function, such as that of T cells, B cells, natural killer cells, dendritic cells, neutrophils, myeloid-derived suppressor cells (MDSCs), macrophages, and Treg cells, thereby enabling MDS-associated malignant cells to evade immune cell surveillance. Alterations in MDS-MSC function include genomic instability, microRNA production, histone modification, DNA methylation, and abnormal signal transduction and cytokine secretion.

Isocitrate dehydrogenase mutations are associated with altered IL-1β responses in acute myeloid leukemia

Mutations in isocitrate dehydrogenase 2 (IDH2) have been noted to impact cellular differentiation in addition to DNA and histone methylation. However, little is known about the impact of IDH2 mutations on intracellular signaling. Using an isogenic cell line model, we investigated both differentiation and signaling responses in IDH2 mutant cells and show augmented responses to inflammatory immune ligands. Using phospho-specific flow and mass cytometry, we demonstrate IDH2 mutant cells were significantly more sensitive to IL-1β at multiple downstream readouts. Further, bulk RNA sequencing confirmed increases in cytokine-related signaling pathways and NF-κB target genes. Single-cell RNA sequencing of unstimulated and stimulated cells confirmed altered IL-1β transcriptional responses in the IDH2 mutant cells. Targeted inhibition of the IKK complex reduced IL-1β responses and induced cell death in primary IDH-mutated leukemia samples. Together, these results confirm altered IL-1β signaling in IDH2 mutant cells and identify this pathway as a potential therapeutic target.

A Phase II Trial of the Double Epigenetic Priming Regimen Including Chidamide and Decitabine for Relapsed/Refractory Acute Myeloid Leukemia

Objective

To explore the role of chidamide, decitabine plus priming regimen in the salvage treatment of relapsed/refractory acute myeloid leukemia.

Methods

A clinical trial was conducted in relapsed/refractory acute myeloid leukemia patients using chidamide, decitabine, cytarabine, idarubicin, and granulocyte-colony stimulating factor, termed CDIAG, a double epigenetic priming regimen.

Results

Thirty-five patients were recruited. Three patients received 2 treatment cycles. In 32 evaluable patients and 35 treatment courses, the completed remission rate (CRR) was 42.9%. The median OS time was 11.7 months. The median OS times of responders were 18.4 months, while those of nonresponders were 7.4 months (P = 0.015). The presence of RUNX1 mutations was associated with a high CRR but a short 2-year OS (P = 0.023) and PFS (P = 0.018) due to relapse after treatment. The presence of IDH mutations had no effect on the remission rate (80.0% vs. 73.3%), but showed a better OS (2-year OS rate: 100.0% vs. 28.9%). Grade 3/4 nonhematological adverse events included pneumonia, hematosepsis, febrile neutropenia, skin and soft tissue infection and others.

Conclusion

The double epigenetic priming regimen (CDIAG regimen) showed considerably good antileukemia activity in these patients. Adverse events were acceptable according to previous experience. The study was registered as a clinical trial.

Clinical Trial Registration

https://clinicaltrials.gov/, identifier:NCT03985007

AML and the art of remission maintenance

Relapse in acute myeloid leukemia (AML) is common, especially in older patients, and there is currently no standard of care maintenance therapy for those who achieve complete remission. Finding effective, tolerable maintenance therapy to prolong remission has been a goal for decades, but early clinical trials testing a variety of agents demonstrated disappointing results with no overall survival benefit. CC-486, an oral hypomethylating agent, was recently approved in the United States for maintenance treatment in patients with AML in first remission following chemotherapy. A number of ongoing studies are assessing various therapeutics in the maintenance setting, including other hypomethylating agents, targeted small-molecule inhibitors, monoclonal antibodies, and immunomodulators. New strategies are needed to identify patients most likely to benefit from maintenance therapy, including those for whom a preemptive approach reliant on monitoring of measurable residual disease would be advantageous.

Enasidenib and ivosidenib in AML

The isocitrate dehydrogenases enzymes, IDH1 and IDH2, catalyze the conversion of isocitrate to α-ketoglutarate (αKG) in the cell cytoplasm and mitochondria, respectively, and contribute to generating the dihydronicotinamide-adenine dinucleotide phosphate (NADPH) as reductive potential in different cellular processes. Mutations in IDH1 and IDH2 genes are found collectively in about 20-25% of acute myeloid leukemia (AML) patients. Mutant IDH enzymes have neomorphic activity and convert αKG to the oncometabolite R-2-hydroxyglutarate (R-2-HG) which accumulates at high levels in the cell and hampers the function of αKG-dependent enzymes, including epigenetic regulators, thus leading to altered gene expression and block of differentiation and contributing to leukemia development. Inhibition of the neomorphic mutants induces marked decrease in R-2-HG levels and restores myeloid differentiation. Enasidenib and ivosidenib are potent and selective inhibitors of mutant IDH2 and IDH1, respectively, act as differentiating agents and showed clinical activity in relapsed/refractory (R/R) AML harboring the specific mutation. As single agents, both drugs have been approved by the Food and Drug Administration (FDA) for the treatment of R/R AML. The relevance of IDH targeting within either single agent approach or, most importantly, combinatorial treatments in AML will be discussed.

Emerging pharmacotherapies for elderly acute myeloid leukemia patients

INTRODUCTION

Acute myeloid leukemia (AML) is a disease mainly seen in the elderly, for which treatment is undergoing rapid changes. Although recent studies have supported the survival benefit of induction chemotherapy in fit patients and that of hypomethylating agents (HMAs) in non-induction candidates, treatment of this patient age population remains a significant challenge for the treating oncologist.

AREAS COVERED

In this review, we will examine effectiveness and safety outcomes of upcoming novel treatment strategies in elderly (≥60 years old) patients with AML, highlight the current literature and ongoing trials able to maximize therapeutic options in this heterogeneous patient population.

EXPERT OPINION

Current developments including new chemotherapeutic strategies and combinations of HMAs with novel drugs targeting epigenetic or immunomodulatory pathways are underway to improve patient survival and quality of life.

Detection Of Mutations In The Isocitrate Dehydrogenase Genes (IDH1/IDH2) Using castPCRTM In Patients With AML And Their Clinical Impact In Mexico City

Objective

Approximately 40–50% of patients with acute myeloid leukaemia (AML) have been reported to present with a normal karyotype and a variable disease-free period, most likely due to the molecular heterogeneity presented by these patients. A variety of mutations have been identified at the molecular level, such as those in the IDH1/2 gene, which causes a gain of function of the isocitrate dehydrogenase enzyme, generating high levels of the (R)-2-hydroxyglutarate oncometabolite, which competitively inhibits dioxygenase enzymes. Therefore, the objective of this study was to evaluate the incidence of IDH1/2 gene mutations in AML patients and their impact on survival.

Materials and methods

A total of 101 patients with a diagnosis of AML were included; mononuclear cells were obtained for DNA extraction and purification. Mutations were detected using TaqMan™ competitive allele-specific probes (castPCR™). Overall survival curves were plotted using IBM SPSS Statistics 23 software.

Results

The frequency of IDH gene mutations was 19.8%. For the IDH1 gene, 13.8% of the mutations identified included R132H, V178I, G105G and R132C. The frequency of mutations of the IDH2 gene was 5.9%; the variants included R172K and R140Q. The mean survival time in patients without IDH1 gene mutations was 173.15 days (120.20–226.10), while the mean survival time for patients with mutations was 54.95 days (9.7–100.18), p = 0.001.

Conclusion

The frequency of IDH1 and IDH2 gene mutations in the sample was similar to that reported in other studies. The analysis of these mutations in AML patients is of great importance as a prognostic factor due to their impact on survival and their use as potential therapeutic targets or as targets of inhibitors of IDH1(Ivosidenib, Tibsovo) and IDH2 (Enasidenib, Idhifa).

The roles of DNA, RNA and histone methylation in ageing and cancer

Chromatin is a macromolecular complex predominantly comprising DNA, histone proteins and RNA. The methylation of chromatin components is highly conserved as it helps coordinate the regulation of gene expression, DNA repair and DNA replication. Dynamic changes in chromatin methylation are essential for cell-fate determination and development. Consequently, inherited or acquired mutations in the major factors that regulate the methylation of DNA, RNA and/or histones are commonly observed in developmental disorders, ageing and cancer. This has provided the impetus for the clinical development of epigenetic therapies aimed at resetting the methylation imbalance observed in these disorders. In this Review, we discuss the cellular functions of chromatin methylation and focus on how this fundamental biological process is corrupted in cancer. We discuss methylation-based cancer therapies and provide a perspective on the emerging data from early-phase clinical trial therapies that target regulators of DNA and histone methylation. We also highlight promising therapeutic strategies, including monitoring chromatin methylation for diagnostic purposes and combination epigenetic therapy strategies that may improve immune surveillance in cancer and increase the efficacy of conventional and targeted anticancer drugs.

IDH1-mutated relapsed or refractory AML: current challenges and future prospects

The prognosis of patients with relapsed or refractory acute myeloid leukemia (R/R AML) is discouraging with salvage standard approaches. Mutations of isocitrate dehydrogenase 1 (IDH1^mut), present in 7–14% of AML patients, have been discovered recently, opening the door to targeted agents aiming to improve the outcomes in this setting. Several oral selective IDH1^mut inhibitors are under investigation, ivosidenib being the first approved for R/R AML. We performed a systematic review to analyze the clinical outcomes and safety reported with IDH1^mut inhibitors and other agents in adult patients with IDH1^mut R/R AML. Ivosidenib in monotherapy achieved complete remission (CR) of 24%, overall response of 42%, and median overall survival of 9 months in R/R AML, and promising outcomes were reported with IDH305 and FT-2102. IDH1^mut inhibitors were generally well tolerated, but some therapy-related toxicities should be monitored, including IDH-differentiation syndrome, prolongation of the QT interval, and leukocytosis, all manageable and reversible. Also, venetoclax, CB-839, PARP inhibitors, and IDH1 peptide vaccine are being studied in IDH1^mut AML. The results of the ongoing and upcoming clinical trials will bring new evidence to establish the role of IDH1^mut inhibitors in therapeutic strategies of AML.

Rational Targeting of Cooperating Layers of the Epigenome Yields Enhanced Therapeutic Efficacy against AML

Disruption of epigenetic regulation is a hallmark of acute myeloid leukemia (AML), but epigenetic therapy is complicated by the complexity of the epigenome. Herein, we developed a long-term primary AML ex vivo platform to determine whether targeting different epigenetic layers with 5-azacytidine and LSD1 inhibitors would yield improved efficacy. This combination was most effective in TET2 ^mut AML, where it extinguished leukemia stem cells and particularly induced genes with both LSD1-bound enhancers and cytosine-methylated promoters. Functional studies indicated that derepression of genes such as GATA2 contributes to drug efficacy. Mechanistically, combination therapy increased enhancer-promoter looping and chromatin-activating marks at the GATA2 locus. CRISPRi of the LSD1-bound enhancer in patient-derived TET2 ^mut AML was associated with dampening of therapeutic GATA2 induction. TET2 knockdown in human hematopoietic stem/progenitor cells induced loss of enhancer 5-hydroxymethylation and facilitated LSD1-mediated enhancer inactivation. Our data provide a basis for rational targeting of cooperating aberrant promoter and enhancer epigenetic marks driven by mutant epigenetic modifiers. SIGNIFICANCE: Somatic mutations of genes encoding epigenetic modifiers are a hallmark of AML and potentially disrupt many components of the epigenome. Our study targets two different epigenetic layers at promoters and enhancers that cooperate to aberrant gene silencing, downstream of the actions of a mutant epigenetic regulator.This article is highlighted in the In This Issue feature, p. 813.

The effects of mutational processes and selection on driver mutations across cancer types

Epidemiological evidence has long associated environmental mutagens with increased cancer risk. However, links between specific mutation-causing processes and the acquisition of individual driver mutations have remained obscure. Here we have used public cancer sequencing data from 11,336 cancers of various types to infer the independent effects of mutation and selection on the set of driver mutations in a cancer type. First, we detect associations between a range of mutational processes, including those linked to smoking, ageing, APOBEC and DNA mismatch repair (MMR) and the presence of key driver mutations across cancer types. Second, we quantify differential selection between well-known alternative driver mutations, including differences in selection between distinct mutant residues in the same gene. These results show that while mutational processes have a large role in determining which driver mutations are present in a cancer, the role of selection frequently dominates.

The role of IDH mutations in acute myeloid leukemia

Isocitrate dehydrogenases (IDHs) are enzymes involved in multiple metabolic and epigenetic cellular processes. Mutations in IDH1 or IDH2 are detected in approximately 20% of patients with acute myeloid leukemia (AML) and induce amino acid changes in conserved residues resulting in neomorphic enzymatic function and production of an oncometabolite, 2-hydroxyglutarate (R-2-HG). This leads to DNA hypermethylation, aberrant gene expression, cell proliferation and abnormal differentiation. IDH mutations diversely affect prognosis of patients with AML based on the location of the mutation and other co-occurring genomic abnormalities. Recently, novel therapies specifically targeting mutant IDH have opened new avenues of therapy for these patients. In the present review, we will provide an overview of the biological, clinical and therapeutic implications of IDH mutations in AML.

Targeted next generation sequencing identified clinically actionable mutations in patients with esophageal sarcomatoid carcinoma

Background

Esophageal sarcomatoid carcinoma (ESC) is a rare disease with a mixture of both carcinomatous and sarcomatous components in the tumor. Its genetic background and mechanisms of oncogenesis remain largely unknown.

Methods

Here we performed targeted next generation sequencing (NGS) on a pan-cancer gene panel in 15 ESC tumors to explore their genetic alterations, and aimed to identify clinically actionable mutations for future treatment instructions.

Results

TP53 alterations were identified in all patients. Alterations in receptor tyrosine kinases (RTK) were identified in 10 out of 15 patients. Members of downstream RAS and PI3-kinase pathways are also mutated in 10 patients, and PIK3CA is the top mutated gene in these pathways. In addition, we identified mutations on histone modification genes in 5 patients, including histone acetyltransferase gene EP300 and its homologue CREBBP, lysine methyltransferase genes KMT2A and KMT2B, and lysine demethylase gene KDM5A. Finally, mismatch repair (MMR) genes and proofreading gene POLE all together were mutated in one third of the ESC patients.

Conclusions

This is the first study to unravel the mutational profile of ESC tumors. Our findings could match 9 patients to the targeted therapies currently available in clinical practice or in active clinical trials, suggesting the potential utility of targeted therapies for this rare disease in the future.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4159-2) contains supplementary material, which is available to authorized users.

The Role for Myc in Coordinating Glycolysis, Oxidative Phosphorylation, Glutaminolysis, and Fatty Acid Metabolism in Normal and Neoplastic Tissues

That cancer cells show patterns of metabolism different from normal cells has been known for over 50 years. Yet, it is only in the past decade or so that an appreciation of the benefits of these changes has begun to emerge. Altered cancer cell metabolism was initially attributed to defective mitochondria. However, we now realize that most cancers do not have mitochondrial mutations and that normal cells can transiently adopt cancer-like metabolism during periods of rapid proliferation. Indeed, an encompassing, albeit somewhat simplified, conceptual framework to explain both normal and cancer cell metabolism rests on several simple premises. First, the metabolic pathways used by cancer cells and their normal counterparts are the same. Second, normal quiescent cells use their metabolic pathways and the energy they generate largely to maintain cellular health and organelle turnover and, in some cases, to provide secreted products necessary for the survival of the intact organism. By contrast, undifferentiated cancer cells minimize the latter functions and devote their energy to producing the anabolic substrates necessary to maintain high rates of unremitting cellular proliferation. Third, as a result of the uncontrolled proliferation of cancer cells, a larger fraction of the metabolic intermediates normally used by quiescent cells purely as a source of energy are instead channeled into competing proliferation-focused and energy-consuming anabolic pathways. Fourth, cancer cell clones with the most plastic and rapidly adaptable metabolism will eventually outcompete their less well-adapted brethren during tumor progression and evolution. This attribute becomes increasingly important as tumors grow and as their individual cells compete in a constantly changing and inimical environment marked by nutrient, oxygen, and growth factor deficits. Here, we review some of the metabolic pathways whose importance has gained center stage for tumor growth, particularly those under the control of the c-Myc (Myc) oncoprotein. We discuss how these pathways differ functionally between quiescent and proliferating normal cells, how they are kidnapped and corrupted during the course of transformation, and consider potential therapeutic strategies that take advantage of common features of neoplastic and metabolic disorders.

The Process and Regulatory Components of Inflammation in Brain Oncogenesis

Central nervous system tumors comprising the primary cancers and brain metastases remain the most lethal neoplasms and challenging to treat. Substantial evidence points to a paramount role for inflammation in the pathology leading to gliomagenesis, malignant progression and tumor aggressiveness in the central nervous system (CNS) microenvironment. This review summarizes the salient contributions of oxidative stress, interleukins, tumor necrosis factor-α(TNF-α), cyclooxygenases, and transcription factors such as signal transducer and activator of transcription 3 (STAT3) and nuclear factor kappa-light-chain-enhancer of activated B-cells (NF-κB) and the associated cross-talks to the inflammatory signaling in CNS cancers. The roles of reactive astrocytes, tumor associated microglia and macrophages, metabolic alterations, microsatellite instability, O⁶-methylguanine DNA methyltransferase (MGMT) DNA repair and epigenetic alterations mediated by the isocitrate dehydrogenase 1 (IDH1) mutations have been discussed. The inflammatory pathways with relevance to the brain cancer treatments have been highlighted.