The role of mutant IDH1 and IDH2 inhibitors in the treatment of acute myeloid leukemia

IDH2 mutations in acute myeloid leukemia

Advances in the treatment of acute myeloid leukemia (AML) over the last 40 years have been limited. With an improved understanding of the pathophysiology of the disease, the advent of new treatment options has enriched the armamentarium of the physician to combat the disease. Mutations of the isocitrate dehydrogenase (IDHs) genes are common in AML and occur in 20-30% of cases. These mutations lead to DNA hypermethylation, aberrant gene expression, cell proliferation, and abnormal differentiation. Targeting mutant IDH, either as monotherapy or in combination with hypomethylating agents (HMAs) or BCL-2 inhibitors, has opened new avenues of therapy for these patients.This review will outline the function of IDHs and focus on the biological effects of IDH2 mutations in AML, their prognosis and treatment options.

Multifunctional targetable liposomal drug delivery system in the management of leukemia: Potential, opportunities, and emerging strategies

The concern impeding the success of chemotherapy in leukemia treatment is descending efficacy of drugs because of multiple drug resistance (MDR). The previous failure of traditional treatment methods is primarily responsible for the present era of innovative agents to treat leukemia effectively. The treatment option is a chemotherapeutic agent in most available treatment strategies, which unfortunately leads to high unavoidable toxicities. As a result of the recent surge in marketed products, theranostic nanoparticles, i.e., multifunctional targetable liposomes (MFTL), have been approved for improved and more successful leukemia treatment that blends therapeutic and diagnostic characteristics. Since they broadly offer the required characteristics to get past the traditional/previous limitations, such as the absence of site-specific anti-cancer therapeutic delivery and ongoing real-time surveillance of the leukemia target sites while administering therapeutic activities. To prepare MFTL, suitable targeting ligands or tumor-specific antibodies are required to attach to the surface of the liposomes. This review exhaustively covered and summarized the liposomal-based formulation in leukemia treatment, emphasizing leukemia types; regulatory considerations, patents, and clinical portfolios to overcome clinical translation hurdles have all been explored.

TMT-based comprehensive proteomic profiling identifies serum prognostic signatures of acute myeloid leukemia

Acute myeloid leukemia (AML) is classified into favorable-risk, intermediate-risk, and poor-risk subtypes. This study aimed to compare the serum proteomic signatures of the three AML subtypes and identify prognostic biomarkers for AML. Serum samples from patients with favorable-risk (n = 14), intermediate-risk (n = 19), and poor-risk AMLs (n = 18) were used for the analysis of tandem mass tag (TMT) labeling-based quantitative proteomics. Comparative analysis was performed to identify differentially expressed proteins (DEPs) between groups. Prognostic proteins were screened using binary logistics regression analysis. TMT-MS/MS proteomics analysis identified 138 DEPs. Fumarate hydratase (FH), isocitrate dehydrogenase 2 (IDH2), and enolase 1 (ENO1) were significantly upregulated in poor-risk patients compared with favorable-risk patients. ELISA assay confirmed that patients with poor-risk AMLs had higher levels of IDH2, ENO1, and FH compared with intermediate-risk AML patients. Logistics analysis identified that proteins 3-hydroxyacyl-CoA dehydrogenase type-2 (HADH, odds ratio (OR) = 1.035, p = 0.010), glutamine synthetase (GLUL, OR = 1.022, p = 0.039), and lactotransferrin (LTF, OR = 1.1224, p = 0.016) were associated with poor prognosis, and proteins ENO1 (OR = 1.154, p = 0.053), FH (OR = 1.043, p = 0.059), and IDH2 (OR = 3.350, p = 0.055) were associated with AML prognosis. This study showed that AML patients had elevated levels of FH, IDH2, ENO1, LTF, and GLUL proteins and might be at high risk of poor prognosis.

Droplet digital PCR for genetic mutations monitoring predicts relapse risk in pediatric acute myeloid leukemia

Multiparameter flow cytometry (MFC)-based minimal residual disease has been a poor predictor of prognosis in children with acute myeloid leukemia (AML). This study aimed to evaluate the incremental value of serial monitoring by droplet digital PCR (ddPCR) in forecasting the outcome of AML. Twenty-four children with AML were enrolled and the relapse-free survival (RFS) rate was estimated using the Kaplan-Meier method. Survival estimates were compared using the log-rank test. Survival analysis showed that the RFS rate in the ddPCR ≥ 0.1% group was significantly lower than that in the < 0.1% group (35.7% ± 19.8% vs. 83.6% ± 10.8%, P = 0.003). Moreover, serial monitoring by ddPCR showed that some mutations remained positive in some patients even though other co-mutations were eliminated, and those patients were more prone to relapse, with a significantly poorer RFS compared to patients negative for mutation (22.0% ± 19.2% vs 83.3% ± 11.3%, P = 0.001). Consequently, ddPCR may assist in prognostic forecasting for pediatric AML.

Small-Molecule Anti-Cancer Drugs From 2016 to 2020: Synthesis and Clinical Application

Malignant tumors have become a significant public health problem that severely threatens human health. Drug-targeting therapy is essential for tumor therapy, along with surgery and radiotherapy. Of the 378 novel drugs approved over the past five years, those for oncological therapy remains at the top (25%). These drugs are used to treat patients with various cancers by acting on corresponding targets, such as EGFR, JAK, BTK, IDH, and FLT3. This review examines anti-tumor agents approved between 2016 and 2020, classifying them according to indication (such as lung cancer, leukemia, breast cancer, and myeloma). These drugs are reviewed according to their route of administration, first-in-class designation, approval dates, and expedited review categories. Furthermore, this paper summarizes the targets and modes of action of the approved anti-tumor drugs while systematically discussing their synthetic routes for medicinal chemistry or industrial use, which will benefit next-generation drug discovery.

The Evolving AML Genomic Landscape: Therapeutic Implications

Improved understanding of the genomic and molecular landscape of acute myeloid leukemia (AML) has resulted in a significant evolution of our understanding of AML biology and allows refined prognostication for those receiving standard combination chemotherapy induction. This dramatic increase in knowledge preceded, and was somewhat responsible for, at least some of eight new FDA drug approvals for AML. This review discusses the impact of genomics on clinical care of AML patients and highlights newly approved FDA drugs. Despite these recent clinical advances, however, the outcome for most patients diagnosed with AML remains dire. Thus, we describe here some of the challenges identified with treating AML including off-target toxicity, drug transporters, clonal heterogeneity, and adaptive resistance, and some of the most promising opportunities for improved therapy.

Identification and characterization of isocitrate dehydrogenase 1 (IDH1) as a functional target of marine natural product grincamycin B

Grincamycins (GCNs) are a class of angucycline glycosides isolated from actinomycete Streptomyces strains that have potent antitumor activities, but their antitumor mechanisms remain unknown. In this study, we tried to identify the cellular target of grincamycin B (GCN B), one of most dominant and active secondary metabolites, using a combined strategy. We showed that GCN B-selective-induced apoptosis of human acute promyelocytic leukemia (APL) cell line NB4 through increase of ER stress and intracellular reactive oxygen species (ROS) accumulation. Using a strategy of combining phenotype, transcriptomics and protein microarray approaches, we identified that isocitrate dehydrogenase 1(IDH1) was the putative target of GCN B, and confirmed that GCNs were a subset of selective inhibitors targeting both wild-type and mutant IDH1 in vitro. It is well-known that IDH1 converts isocitrate to 2-oxoglutarate (2-OG), maintaining intracellular 2-OG homeostasis. IDH1 and its mutant as the target of GCN B were validated in NB4 cells and zebrafish model. Knockdown of IDH1 in NB4 cells caused the similar phenotype as GCN B treatment, and supplementation of N-acetylcysteine partially rescued the apoptosis caused by IDH1 interference in NB4 cells. In zebrafish model, GCN B effectively restored myeloid abnormality caused by overexpression of mutant IDH1(R132C). Taken together, we demonstrate that IDH1 is one of the antitumor targets of GCNs, suggesting wild-type IDH1 may be a potential target for hematological malignancies intervention in the future.

Assessing acquired resistance to IDH1 inhibitor therapy by full-exon IDH1 sequencing and structural modeling

Somatic mutations in hotspot regions of the cytosolic or mitochondrial isoforms of the isocitrate dehydrogenase gene (IDH1 and IDH2, respectively) contribute to the pathogenesis of acute myeloid leukemia (AML) by producing the oncometabolite 2-hydroxyglutarate (2-HG). The allosteric IDH1 inhibitor, ivosidenib, suppresses 2-HG production and induces clinical responses in relapsed/refractory IDH1-mutant AML. Herein, we describe a clinical case of AML in which we detected the neomorphic IDH1 p.R132C mutation in consecutive patient samples with a mutational hotspot targeted next-generation sequencing (NGS) assay. The patient had a clinical response to ivosidenib, followed by relapse and disease progression. Subsequent sequencing of the relapsed sample using a newly developed all-exon, hybrid-capture-based NGS panel identified an additional IDH1 p.S280F mutation known to cause renewed 2-HG production and drug resistance. Structural modeling confirmed that serine-to-phenylalanine substitution at this codon sterically hinders ivosidenib from binding to the mutant IDH1 dimer interface and predicted a similar effect on the pan-IDH inhibitor AG-881. Joint full-exon NGS and structural modeling enables monitoring IDH1 inhibitor-treated AML patients for acquired drug resistance and choosing follow-up therapy.

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.

Impact of next generation sequencing results on clinical management in patients with hematological disorders

Application of next generation sequencing (NGS) has shed light on the molecular heterogeneity of hematological malignancies. NGS panels targeting recurrent mutations have become common in many large centers and commercial laboratories. However, its impact in clinical practice is unclear. We sought to characterize the use of NGS at a tertiary care center in an observational study of 343 patients with suspected hematological malignancies. We found that NGS changed or refined the clinical and pathologic diagnosis in 9% of patients and affected management decisions in 65% (including clinical trial eligibility, targeted therapy selection, and consideration for stem cell transplantation). This study emphasizes early incorporation of NGS in clinical practice while also highlighting the present limitations. As our understanding of these disorders increases and more clinically relevant genetic targets emerge, it will be important to refine the molecular testing strategy to deliver personalized medicine given the high cost associated with this technology.

Impact of a 40-Gene Targeted Panel Test on Physician Decision Making for Patients With Acute Myeloid Leukemia

PURPOSE

Physicians treating hematologic malignancies increasingly order targeted sequencing panels to interrogate recurrently mutated genes. The precise impact of these panels on clinical decision making is not well understood.

METHODS

Here, we report our institutional experience with a targeted 40-gene panel (MyeloSeq) that is used to generate a report for both genetic variants and variant allele frequencies for the treating physician (the limit of mutation detection is approximately one AML cell in 50).

RESULTS

In total, 346 sequencing reports were generated for 325 patients with suspected hematologic malignancies over an 8-month period (August 2018 to April 2019). To determine the influence of genomic data on clinical care for patients with acute myeloid leukemia (AML), we analyzed 122 consecutive reports from 109 patients diagnosed with AML and surveyed the treating physicians with a standardized questionnaire. The panel was ordered most commonly at diagnosis (61.5%), but was also used to assess response to therapy (22.9%) and to detect suspected relapse (15.6%). The panel was ordered at multiple timepoints during the disease course for 11% of patients. Physicians self-reported that 50 of 114 sequencing reports (44%) influenced clinical care decisions in 44 individual patients. Influences were often nuanced and extended beyond identifying actionable genetic variants with US Food and Drug Administration-approved drugs.

CONCLUSION

This study provides insights into how physicians are currently using multigene panels capable of detecting relatively rare AML cells. The most influential way to integrate these tools into clinical practice will be to perform prospective clinical trials that assess patient outcomes in response to genomically driven interventions.

The oncometabolite R-2-hydroxyglutarate dysregulates the differentiation of human mesenchymal stromal cells via inducing DNA hypermethylation

Background

Isocitrate dehydrogenase (IDH1/2) gene mutations are the most frequently observed mutations in cartilaginous tumors. The mutant IDH causes elevation in the levels of R-enantiomer of 2-hydroxylglutarate (R-2HG). Mesenchymal stromal cells (MSCs) are reasonable precursor cell candidates of cartilaginous tumors. This study aimed to investigate the effect of oncometabolite R-2HG on MSCs.

Methods

Human bone marrow MSCs treated with or without R-2HG at concentrations 0.1 to 1.5 mM were used for experiments. Cell Counting Kit-8 was used to detect the proliferation of MSCs. To determine the effects of R-2HG on MSC differentiation, cells were cultured in osteogenic, chondrogenic and adipogenic medium. Specific staining approaches were performed and differentiation-related genes were quantified. Furthermore, DNA methylation status was explored by Illumina array-based arrays. Real-time PCR was applied to examine the signaling component mRNAs involved in.

Results

R-2HG showed no influence on the proliferation of human MSCs. R-2HG blocked osteogenic differentiation, whereas promoted adipogenic differentiation of MSCs in a dose-dependent manner. R-2HG inhibited chondrogenic differentiation of MSCs, but increased the expression of genes related to chondrocyte hypertrophy in a lower concentration (1.0 mM). Moreover, R-2HG induced a pronounced DNA hypermethylation state of MSC. R-2HG also improved promotor methylation of lineage-specific genes during osteogenic and chondrogenic differentiation. In addition, R-2HG induced hypermethylation and decreased the mRNA levels of SHH, GLI1and GLI2, indicating Sonic Hedgehog (Shh) signaling inhibition.

Conclusions

The oncometabolite R-2HG dysregulated the chondrogenic and osteogenic differentiation of MSCs possibly via induction of DNA hypermethylation, improving the role of R-2HG in cartilaginous tumor development.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-020-07744-x.

Antigen Expression Varies Significantly between Molecular Subgroups of Acute Myeloid Leukemia Patients: Clinical Applicability Is Hampered by Establishment of Relevant Cutoffs

INTRODUCTION

In this single-center study of 268 acute myeloid leukemia (AML) patients, we have tested if a subset of 4 routinely employed immunophenotypic stem cell-associated markers correlated with the presence of recurrently mutated genes and if the markers were predictive for mutational status.

METHODS

Immunophenotypic data from 268 diagnostic AML samples obtained in 2009-2018 were analyzed retrospectively for the antigens CD34, CD117, CD123, and CLEC12A. Correlation between immunophenotypes and mutations was analyzed by Fischer's exact test. Clinical applicability of the markers for predicting mutational status was evaluated by receiver operating characteristics analyses, where an area under the curve (AUC) of at least 0.85 was accepted as clinically relevant.

RESULTS

For a number of genes, the antigen expression differed significantly between mutated and wild-type gene expression. Despite low AUCs, CD123 and CLEC12A correlated with FLT3+NPM1- and FLT3+NPM1+. Three subsets met the AUC requirements (CD34+, CD34+CD117+, and CD34-CD117+) for predicting FLT3-NPM1+ or FLT3+NPM1+.

CONCLUSION

The value of immunophenotypes as surrogate markers for mutational status in AML seems limited when employing CD123 and CLEC12A in combination with CD34 and CD117. Defining relevant cutoffs for given markers is challenging and hampered by variation between laboratories and patient groups.

Common genetic predisposition for heart failure and cancer

Cardiovascular diseases and cancer are major causes of mortality in industrialized societies. They share common risk factors (e.g., genetics, lifestyle, age, infection, toxins, and pollution) and might also mutually promote the onset of the respective other disease. Cancer can affect cardiac function directly while antitumor therapies may have acute- and/or late-onset cardiotoxic effects. Recent studies suggest that heart failure might promote tumorigenesis and tumor progression. In both cancer and cardiovascular diseases, genetic predisposition is implicated in the disease onset and development. In this regard, genetic variants classically associated with cardiomyopathies increase the risk for toxic side effects on the cardiovascular system. Genetic variants associated with increased cancer risk are frequent in patients with peripartum cardiomyopathy complicated by cancer, pointing to a common genetic predisposition for both diseases. Common risk factors, cardiotoxic antitumor treatment, genetic variants (associated with cardiomyopathies and/or cancer), and increased cardiac stress lead us to propose the "multi-hit hypothesis" linking cancer and cardiovascular diseases. In the present review, we summarize the current knowledge on potential connecting factors between cancer and cardiovascular diseases with a major focus on the role of genetic predisposition and its implication for individual therapeutic strategies and risk assessment in the novel field of oncocardiology.

Landscape of Tumor Suppressor Mutations in Acute Myeloid Leukemia

Acute myeloid leukemia is mainly characterized by a complex and dynamic genomic instability. Next-generation sequencing has significantly improved the ability of diagnostic research to molecularly characterize and stratify patients. This detailed outcome allowed the discovery of new therapeutic targets and predictive biomarkers, which led to develop novel compounds (e.g., IDH 1 and 2 inhibitors), nowadays commonly used for the treatment of adult relapsed or refractory AML. In this review we summarize the most relevant mutations affecting tumor suppressor genes that contribute to the onset and progression of AML pathology. Epigenetic modifications (TET2, IDH1 and IDH2, DNMT3A, ASXL1, WT1, EZH2), DNA repair dysregulation (TP53, NPM1), cell cycle inhibition and deficiency in differentiation (NPM1, CEBPA, TP53 and GATA2) as a consequence of somatic mutations come out as key elements in acute myeloid leukemia and may contribute to relapse and resistance to therapies. Moreover, spliceosomal machinery mutations identified in the last years, even if in a small cohort of acute myeloid leukemia patients, suggested a new opportunity to exploit therapeutically. Targeting these cellular markers will be the main challenge in the near future in an attempt to eradicate leukemia stem cells.

Oncometabolites in renal cancer

The study of cancer metabolism has evolved vastly beyond the remit of tumour proliferation and survival with the identification of the role of 'oncometabolites' in tumorigenesis. Simply defined, oncometabolites are conventional metabolites that, when aberrantly accumulated, have pro-oncogenic functions. Their discovery has led researchers to revisit the Warburg hypothesis, first postulated in the 1950s, of aberrant metabolism as an aetiological determinant of cancer. As such, the identification of oncometabolites and their utilization in diagnostics and prognostics, as novel therapeutic targets and as biomarkers of disease, are areas of considerable interest in oncology. To date, fumarate, succinate, L-2-hydroxyglutarate (L-2-HG) and D-2-hydroxyglutarate (D-2-HG) have been characterized as bona fide oncometabolites. Extensive metabolic reprogramming occurs during tumour initiation and progression in renal cell carcinoma (RCC) and three oncometabolites - fumarate, succinate and L-2-HG - have been implicated in this disease process. All of these oncometabolites inhibit a superfamily of enzymes known as α-ketoglutarate-dependent dioxygenases, leading to epigenetic dysregulation and induction of pseudohypoxic phenotypes, and also have specific pro-oncogenic capabilities. Oncometabolites could potentially be exploited for the development of novel targeted therapies and as biomarkers of disease.

The Landscape of the Anti-Kinase Activity of the IDH1 Inhibitors

Isocitrate dehydrogenases constitute a class of enzymes that are crucial for cellular metabolism. The overexpression or mutation of isocitrate dehydrogenases are often found in leukemias, glioblastomas, lung cancers, and ductal pancreatic cancer among others. Mutation R132H, which changes the functionality of an enzyme to produce mutagenic 2-hydroxyglutarate instead of a normal product, is particularly important in this field. A series of inhibitors were described for these enzymes of which ivosidenib was the first to be approved for treating leukemia and bile duct cancers in 2018. Here, we investigated the polypharmacological landscape of the activity for known sulfamoyl derivatives that are inhibitors, which are selective towards IDH1 R132H. These compounds appeared to be effective inhibitors of several non-receptor kinases at a similar level as imatinib and axitinib. The antiproliferative activity of these compounds against a panel of cancer cells was tested and is explained based on the relative expression levels of the investigated proteins. The multitargeted activity of these compounds makes them valuable agents against a wide range of cancers, regardless of the status of IDH1.

The Time Has Come for Targeted Therapies for AML: Lights and Shadows

Acute myeloid leukemia (AML) is a complex disease characterized by genetic and clinical heterogeneity and high mortality. After 40 years during which the standard of care for patients evolved very little, the therapeutic landscape has recently seen rapid changes, with the approval of eight new drugs by the Food and Drug Administration (FDA) within the last 2 years, providing new opportunities, as well as new challenges, for treating clinicians. These therapies include FLT3 inhibitors midostaurin and gilteritinib, CPX-351 (liposomal cytarabine and daunorubicin), gemtuzumab ozogamicin (GO, anti-CD33 monoclonal antibody conjugated with calicheamicin), IDH1/IDH2 inhibitors ivosidenib and enasidenib, Hedgehog inhibitor glasdegib, and BCL-2 inhibitor venetoclax. In this review, we summarize currently available data on these new drugs and discuss the rapidly evolving therapeutic armamentarium for AML, focusing on targeted therapies.

Targeted therapy in acute myeloid leukemia: current status and new insights from a proteomic perspective

Introduction: The biological heterogeneity of acute myeloid leukemia (AML) complicates personalized medicine. Individual prognosis is typically based on the presence of chromosomal and genetic lesions. Nevertheless, these classifications often lack a priori information about response to therapy. Since the protein expression landscape reflects the functional activity state of cells, we hypothesize that analyzing this can be used for the identification of protein activity markers to provide better risk stratification as well as may provide targeted therapeutic guidance in AML.Areas covered: Herein, we review recently new adopted drugs in the treatment for AML and discuss how quantitative proteomic techniques may contribute to better therapeutic selection in AML.Expert commentary: The net functional state of the cell is defined by the activity of protein within all the pathways that are active in the cell. Recognition of the proteomic profile of the leukemic blast could, therefore, complement current classification systems by providing a better a priori description of what pathways are important within a cell as a guide to the selection of therapy for the patient.

Therapeutic Choice in Older Patients with Acute Myeloid Leukemia: A Matter of Fitness

Acute myeloid leukemia (AML), with an incidence increasing with age, is the most common acute leukemia in adults. Concurrent comorbidities, mild to severe organ dysfunctions, and low performance status (PS) are frequently found in older patients at the onset, conditioning treatment choice and crucially influencing the outcome. Although anthracyclines plus cytarabine-based chemotherapy, also called “7 + 3” regimen, remains the standard of care in young adults, its use in patients older than 65 years should be reserved to selected cases because of higher incidence of toxicity. These adverse features of AML in the elderly underline the importance of a careful patient assessment at diagnosis as a critical tool in the decision-making process of treatment choice. In this review, we will describe selected recently approved drugs as well as examine prognostic algorithms that may be helpful to assign treatment in elderly patients properly.

Functional and topographic effects on DNA methylation in IDH1/2 mutant cancers

IDH1/2 mutations are early drivers present in diverse human cancer types arising in various tissue sites. IDH1/2 mutation is known to induce a global hypermethylator phenotype. However, the effects on DNA methylation across IDH mutant cancers and functionally different genome regions, remain unknown. We analyzed DNA methylation data from IDH1/2 mutant acute myeloid leukemia, oligodendroglioma, astrocytoma, solid papillary breast carcinoma with reverse polarity, sinonasal undifferentiated carcinoma and cholangiocarcinoma, which clustered by their embryonal origin. Hypermethylated common probes affect predominantly gene bodies while promoters in IDH1/2 mutant cancers remain unmethylated. Enhancers showed global hypermethylation, however commonly hypomethylated enhancers were associated with tissue differentiation and cell fate determination. We demonstrate that some chromosomes, chromosomal arms and chromosomal regions are more affected by IDH1/2 mutations while others remain resistant to IDH1/2 mutation induced methylation changes. Therefore IDH1/2 mutations have different methylation effect on different parts of the genome, which may be regulated by different mechanisms.

Tumor Metabolism as a Regulator of Tumor-Host Interactions in the B-Cell Lymphoma Microenvironment-Fueling Progression and Novel Brakes for Therapy

Tumor metabolism and its specific alterations have become an integral part of understanding functional alterations leading to malignant transformation and maintaining cancer progression. Here, we review the metabolic changes in B-cell neoplasia, focusing on the effects of tumor metabolism on the tumor microenvironment (TME). Particularly, innate and adaptive immune responses are regulated by metabolites in the TME such as lactate. With steadily increasing therapeutic options implicating or utilizing the TME, it has become essential to address the metabolic alterations in B-cell malignancy for therapeutic approaches. In this review, we discuss metabolic alterations of B-cell lymphoma, consequences for currently used therapy regimens, and novel approaches specifically targeting metabolism in the TME.

Epigenetic Changes as a Target in Aging Haematopoietic Stem Cells and Age-Related Malignancies

Aging is associated with multiple molecular and functional changes in haematopoietic cells. Most notably, the self-renewal and differentiation potential of hematopoietic stem cells (HSCs) are compromised, resulting in myeloid skewing, reduced output of red blood cells and decreased generation of immune cells. These changes result in anaemia, increased susceptibility for infections and higher prevalence of haematopoietic malignancies. In HSCs, age-associated global epigenetic changes have been identified. These epigenetic alterations in aged HSCs can occur randomly (epigenetic drift) or are the result of somatic mutations in genes encoding for epigenetic proteins. Mutations in loci that encode epigenetic modifiers occur frequently in patients with haematological malignancies, but also in healthy elderly individuals at risk to develop these. It may be possible to pharmacologically intervene in the aberrant epigenetic program of derailed HSCs to enforce normal haematopoiesis or treat age-related haematopoietic diseases. Over the past decade our molecular understanding of epigenetic regulation has rapidly increased and drugs targeting epigenetic modifications are increasingly part of treatment protocols. The reversibility of epigenetic modifications renders these targets for novel therapeutics. In this review we provide an overview of epigenetic changes that occur in aging HSCs and age-related malignancies and discuss related epigenetic 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.

Intersection of Epigenetic and Metabolic Regulation of Histone Modifications in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is one of the most lethal blood cancers, accounting for close to a quarter of a million annual deaths worldwide. Even though genetically heterogeneous, all AMLs are characterized by two interrelated features—blocked differentiation and high proliferative capacity. Despite significant progress in our understanding of the molecular and genetic basis of AML, the treatment of AMLs with chemotherapeutic regimens has remained largely unchanged in the past 30 years. In this review, we will consider the role of two cellular processes, metabolism and epigenetics, in the development and progression of AML and highlight the studies that suggest an interconnection of therapeutic importance between the two. Large-scale whole-exome sequencing of AML patients has revealed the presence of mutations, translocations or duplications in several epigenetic effectors such as DNMT3, MLL, ASXL1, and TET2, often times co-occuring with mutations in metabolic enzymes such as IDH1 and IDH2. These mutations often result in impaired enzymatic activity which leads to an altered epigenetic landscape through dysregulation of chromatin modifications such as DNA methylation, histone acetylation and methylation. We will discuss the role of enzymes that are responsible for establishing these modifications, namely histone acetyl transferases (HAT), histone methyl transferases (HMT), demethylases (KDMs), and deacetylases (HDAC), and also highlight the merits and demerits of using inhibitors that target these enzymes. Furthermore, we will tie in the metabolic regulation of co-factors such as acetyl-CoA, SAM, and α-ketoglutarate that are utilized by these enzymes and examine the role of metabolic inhibitors as a treatment option for AML. In doing so, we hope to stimulate interest in this topic and help generate a rationale for the consideration of the combinatorial use of metabolic and epigenetic inhibitors for the treatment of AML.

Enasidenib in the treatment of relapsed/refractory acute myeloid leukemia: an evidence-based review of its place in therapy

Introduction: Acute myeloid leukemia (AML) remains a disease with high mortality, especially for older patients and those with relapsed/refractory (R/R) disease. With recent advances in molecular testing, targeting particular leukemogenic mutations such as those occurring in isocitrate dehydrogenase (IDH) became possible. Enasidenib is a new small-molecule inhibitor of mutant isocitrate dehydrogenase-2 (IDH2). Aim: The objective of this article is to review the evidence for the use of enasidenib in R/R AML, as well as to outline future directions of enasidenib therapy. Evidence Review: Enasidenib was approved in August 2017, after a successful Phase I/II trial showing an overall response rate (ORR) of 40.3% in R/R disease, with 19.3% of patients achieving complete remission (CR). Enrollees in the trial were mostly older adults. The most prominent toxicities were hyperbilirubinemia and IDH-differentiation syndrome (IDH-DS), though the drug was generally well tolerated and the maximum tolerated dose was not reached. A Phase III trial is currently ongoing. Conclusion: Enasidenib provides a new therapeutic option for patients with R/R AML. Further studies are ongoing to ascertain its role in combination with other agents and newly diagnosed disease.

New Targeted Agents in Acute Myeloid Leukemia: New Hope on the Rise

The therapeutic approach for acute myeloid leukemia (AML) remains challenging, since over the last four decades a stagnation in standard cytotoxic treatment has been observed. But within recent years, remarkable advances in the understanding of the molecular heterogeneity and complexity of this disease have led to the identification of novel therapeutic targets. In the last two years, seven new targeted agents (midostaurin, gilteritinib, enasidenib, ivosidenib, glasdegib, venetoclax and gemtuzumab ozogamicin) have received US Food and Drug Administration (FDA) approval for the treatment of AML. These drugs did not just prove to have a clinical benefit as single agents but have especially improved AML patient outcomes if they are combined with conventional therapy. In this review, we will focus on currently approved and promising upcoming agents and we will discuss controversial aspects and limitations of targeted treatment strategies.

Emerging drug profile: Krebs cycle and cancer: IDH mutations and therapeutic implications

Mutations in IDH1 and IDH2 genes occur frequently in myeloid malignancies and certain solid tumors. IDH1 and IDH2 are enzymes that are involved in the tricarboxylic acid (TCA) cycle. Activating mutations in IDH1 and IDH2 leads to increased production of 2-hydroxygluterate and epigenetic modification, affecting cell differentiation. Small molecule inhibitors of mutated IDH1 and IDH2 have shown promising anti-cancer activity in both preclinical models and early clinical trials. Recently, enasidenib and ivosidenib, oral inhibitors of mutated IDH2 and IDH1 genes, respectively, were approved for use in relapsed or refractory acute myeloid leukemia. This review will focus on the underlying biological mechanism and clinical relevance of IDH mutations in cancer.

Epigenetic Modifications in Acute Myeloid Leukemia: Prognosis, Treatment, and Heterogeneity

Leukemia, specifically acute myeloid leukemia (AML), is a common malignancy that can be differentiated into multiple subtypes based on leukemogenic history and etiology. Although genetic aberrations, particularly cytogenetic abnormalities and mutations in known oncogenes, play an integral role in AML development, epigenetic processes have been shown as a significant and sometimes independent dynamic in AML pathophysiology. Here, we summarize how tumors evolve and describe AML through an epigenetic lens, including discussions on recent discoveries that include prognostics from epialleles, changes in RNA function for hematopoietic stem cells and the epitranscriptome, and novel epigenetic treatment options. We further describe the limitations of treatment in the context of the high degree of heterogeneity that characterizes acute myeloid leukemia.

Cellular immunotherapy for acute myeloid leukemia: How specific should it be?

Significant improvements in the survival of patients with hematological cancers following hematopoietic stem cell transplantation provide evidence supporting the potency of immune cell-mediated anti-leukemic effects. Studies focusing on immune cell-based cancer therapies have made significant breakthroughs in the last few years. Adoptive cellular therapy (ACT), and chimeric antigen receptor (CAR) T cell therapy, in particular, has significantly increased the survival of patients with B cell acute lymphoblastic leukemia and aggressive B cell lymphoma. Despite antigen-negative relapses and severe toxicities such as cytokine release syndrome after treatment, CAR-T cell therapies have been approved by the FDA in some conditions. Although a number of studies have tried to achieve similar results for acute myeloid leukemia (AML), clinical outcomes have not been as promising. In this review, we summarize recent and ongoing studies on cellular therapies for AML patients, with a focus on antigen-specific versus -nonspecific approaches.

Next Generation Sequencing in AML-On the Way to Becoming a New Standard for Treatment Initiation and/or Modulation?

Acute myeloid leukemia (AML) is a clonal disease caused by genetic abberations occurring predominantly in the elderly. Next generation sequencing (NGS) analysis has led to a deeper genetic understanding of the pathogenesis and the role of recently discovered genetic precursor lesions (clonal hematopoiesis of indeterminate/oncogenic potential (CHIP/CHOP)) in the evolution of AML. These advances are reflected by the inclusion of certain mutations in the updated World Health Organization (WHO) 2016 classification and current treatment guidelines by the European Leukemia Net (ELN) and National Comprehensive Cancer Network (NCCN) and results of mutational testing are already influencing the choice and timing of (targeted) treatment. Genetic profiling and stratification of patients into molecularly defined subgroups are expected to gain ever more weight in daily clinical practice. Our aim is to provide a concise summary of current evidence regarding the relevance of NGS for the diagnosis, risk stratification, treatment planning and response assessment in AML, including minimal residual disease (MRD) guided approaches. We also summarize recently approved drugs targeting genetically defined patient populations with risk adapted- and individualized treatment strategies.

Genome-scale drop-out screens to identify cancer cell vulnerabilities in AML

Acute myeloid leukemia (AML) is an aggressive cancer that remains lethal to the majority of sufferers. Whilst the mainstay treatments for this condition have remained largely unchanged over the past five decades, progress in deciphering its pathogenesis has accelerated in recent years, propelled in part by advances in cancer genomics and mechanistic studies of leukemogenic mutations. Newer molecular therapies targeting aberrant biological pathways are currently under investigation with a few moving closer to clinical use. However, collectively, these new therapies are not predicted to have a major impact on clinical outcomes and the need for the identification of further therapeutic targets in AML remains critical. Recently the use of CRISPR-Cas9 systems for genome editing and their potential application in genome-wide screening has opened a new frontier for unbiased discovery of therapeutic vulnerabilities in cancer and AML was the first disease in which this technology was systematically applied. In this review we give an overview of recent advances in identifying novel therapeutic vulnerabilities of AML using CRISPR-Cas9 and discuss possible future applications of CRISPR technologies in this field.

Epigenetic therapy combinations in acute myeloid leukemia: what are the options?

Epigenetics refers to the regulation of gene expression mainly by changes in DNA methylation and modifications of histone proteins without altering the actual DNA sequence. While epigenetic modifications are essential for normal cell differentiation, several driver mutations in leukemic pathogenesis have been identified in genes that affect epigenetic processes, such as DNA methylation and histone acetylation. Several therapeutic options to target epigenetic alterations in acute myeloid leukemia (AML) have been successfully tested in preclinical studies and various drugs have already been approved for use in clinical practice. Among these already approved therapeutics are hypomethylating agents (azacitidine and decitabine) and isocitrate dehydrogenase inhibitors (ivosidenib, enasidenib). Other agents such as bromodomain-containing epigenetic reader proteins and histone methylation (e.g. DOT1L) inhibitors are currently in advanced clinical testing. As several epigenetic therapies have only limited efficacy when used as single agents, combination therapies that target AML pathogenesis at different levels and exploit synergistic mechanisms are also in clinical trials. Combinations of either epigenetic therapies with conventional chemotherapy, different forms of epigenetic therapies, or epigenetic therapies with immunotherapy are showing promising early results. In this review we summarize the underlying pathophysiology and rationale for epigenetically-based combination therapies, review current preclinical and clinical data and discuss the future directions of epigenetic therapy combinations in AML.

Chemotherapy Treatment and Trials in Low-Grade Gliomas

There is currently no universally accepted standard of care treatment for low-grade gliomas, a molecularly heterogeneous group of tumors with similarly heterogeneous clinical outcomes. Risk stratification by clinical and molecular features is useful to help determine which patients benefit the most from adjuvant treatment. The addition of combination chemotherapy with procarbazine, lomustine, and vincristine confers survival advantage, as likely does temozolomide, but radiochemotherapy may not be appropriate for all patients owing to its toxicity profile. We review the approach to treatment in patients with low-grade gliomas with an emphasis on the clinical trials focusing on adjuvant chemotherapy in this population.

Molecular Pathogenesis of Low-Grade Glioma

Advances in genome sequencing have elucidated the genetics of low-grade glioma. Available evidence indicates a neomorphic mutation in isocitrate dehydrogenase (IDH) initiates gliomagenesis. Mutant IDH produces the oncometabolite 2-hydroxyglutarate, which inhibits enzymes that demethylate genomic DNA and histones. Recent findings by the authors and others suggest the ensuing hypermethylation alters chromatin conformation and the transcription factor landscape in brain progenitor cells, leading to a block in differentiation and tumor initiation. Work in preclinical models has identified selective metabolic and molecular vulnerabilities of low-grade glioma. These new concepts will trigger a wave of innovative clinical trials in the near future.

Evaluating ivosidenib for the treatment of relapsed/refractory AML: design, development, and place in therapy

Improvements in the last decade in understanding the molecular mechanisms underlying acute myeloid leukemia (AML) have emphasized that treatment regimens should be personalized with agents that can selectively target genetic abnormalities if present. Neomorphic mutations in isoform 1 of isocitrate dehydrogenase (IDH1) result in the formation of the onco-metabolite R-2-hydroxyglutarate, which drives leukemic transformation by affecting processes such as chromatin remodeling, the cellular defense against oxidative stress and cell survival. Preclinical studies with small molecule inhibitors have validated mutant IDH1 as a molecular target, and a recent Phase 1 clinical trial with the first mutant IDH1 inhibitor ivosidenib has prompted approval by the US Food and Drug Association for the treatment of patients with IDH1-mutated AML in the relapsed and refractory setting due to impressive results. This approval has given a group of patients, that otherwise has a very poor prognosis and limited options, new hope, and it is to be expected that more indications for ivosidenib will follow soon. These developments highlight the potential of precision medicine in AML, with more agents currently under evaluation in clinical trials. Although the first reports have also already emerged describing acquired resistance for these mutant IDH inhibitors, combination treatment might overcome this problem, which could drastically change the treatment landscape of AML over the next few years.

Pharmacokinetics and safety of Enasidenib following single oral doses in Japanese and Caucasian subjects

The aim of this study was to assess and compare the pharmacokinetics (PK) and safety of Enasidenib in healthy adult male Japanese subjects to healthy adult male Caucasian subjects. This was a phase 1, single dose study to evaluate the PK and safety of Enasidenib in healthy adult male Japanese subjects relative to healthy adult male Caucasian subjects. A total of 62 subjects (31 Japanese and 31 Caucasian) were enrolled into three dose cohorts (single doses of 50 mg, 100 mg, or 300 mg Enasidenib). Blood samples for PK assessment were collected up to 672 hours postdose. Safety was evaluated throughout the study. In the present study, we found that PK exposures of Enasidenib and its metabolite AGI-16903 for Caucasian and Japanese subjects were comparable at the 50, 100, and 300 mg dose levels, demonstrated by that the 90% confidence intervals (CIs) of geometric mean ratios for AUCs and Cmax between these two populations generally contained 100% from all three treatment cohorts. In conclusion, PK exposures of Enasidenib and its metabolite AGI-16903 for Caucasians and Japanese subjects were comparable and Enasidenib was safe and well tolerated with no apparent differences between Japanese and Caucasian subjects when administered as single oral doses of 50 mg, 100 mg, and 300 mg.

New drugs for acute myeloid leukemia inspired by genomics and when to use them

We are several years into the "postdiscovery" era in acute myeloid leukemia (AML) thanks to extensive work involving the sequencing of genomes and exomes of countless patients, which has led to routine comprehensive targeted sequencing in clinical care. The ability to unlock the molecular underpinnings of each patient's disease was supposed to usher in a new treatment era in which each patient was assigned, based on her mutational profile, a personalized cocktail of targeted therapies that would snuff the disease into submission with minimal toxicity. Whether we have fully realized the promise of personalized therapy in AML is unclear. Here, I review those new drugs that have been inspired by genomics, discuss others that might be possible and their potential roles, and consider whether the ability to target genomic mutations in a personalized manner constitutes the future of AML therapeutics or is representative of an era that has already passed.

Reduced Levels of ATP Synthase Subunit ATP5F1A Correlate with Earlier-Onset Prostate Cancer

Switching of cellular energy production from oxidative phosphorylation (OXPHOS) to aerobic glycolysis occurs in many types of tumors. However, the significance of energy metabolism for the development of prostate carcinoma is poorly understood. We investigated the expression of OXPHOS complexes in 94 human prostate carcinomas and paired benign tissue using immunohistochemistry. Overall mitochondrial mass was upregulated in carcinomas compared to benign prostate tissue in all Gleason grades. A significant direct correlation between the expression of OXPHOS complexes I, II, and V and the Gleason score was observed. However, 17% of prostate carcinomas and 18% of benign prostate tissues showed isolated or combined deficiency of OXPHOS complexes (one deficiency in 12% of the tumors, combined deficiencies in 5%). Complex I was absent in 9% of the samples, with only parts of the tumor affected. ATP5F1A, a complex V protein, was the most frequently affected subunit, in 10% of tumors and 11% of benign prostate tissues (but not both tissues in any single patient). A possible role of complex V in prostate cancer development is suggested by the significant positive correlation of ATP5F1A levels with earlier-onset prostate cancer (age at diagnosis and at prostatectomy) and free PSA percentage. The relatively high percentage (17%) of prostate carcinomas with regional foci of partial OXPHOS complex deficiencies could have important therapeutic implications.

Low level of isocitrate dehydrogenase 1 predicts unfavorable postoperative outcomes in patients with clear cell renal cell carcinoma

Background

The purpose of this study was to investigate the role of isocitrate dehydrogenase 1 (IDH1) expression on prognosis of patients with clear cell renal cell carcinoma (ccRCC) following nephrectomy.

Methods

We retrospectively enrolled 358 ccRCC patients undergoing nephrectomy in Renji Hospital. Clinicopathologic features, overall survival (OS) and recurrence-free survival (RFS) of ccRCC patents were all collected. IDH1 expression level was assessed by immunohistochemistry and its association with clinicopathologic features and outcomes were also evaluated. Kaplan-Meier method with the log-rank test was applied to compare survival curves. Multivariate cox regression models were applied to analyze the prognostic value of each factor on OS and RFS of ccRCC patients. Moreover, two nomograms with factors selected by multivariate analysis were constructed to evaluate the prognosis of ccRCC patients, and the calibration plots were built to assess the predictive accuracy of nomograms.

Results

Our data indicated that IDH1 expression level was down-regulated in ccRCC tissues, and it negatively correlated with tumor Fuhrman grade (p = 0.025). Low IDH1 expression was associated with worse OS and RFS for cccRCC patients (OS, p = 0.004; RFS, p = 0.03). In addition, IDH1 could significantly stratify patients’ OS and RFS in intermediate/high risk patients (UISS score ≥ 4) (p = 0.049 and p = 0.004, respectively). Furthermore, incorporating IDH1 with other prognostic factors could predict ccRCC patients’ OS and RFS (OS, c-index = 0.779; RFS, c-index = 0.798) and perform better than TNM and SSIGN system.

Conclusions

Low IDH1 expression level might be an adverse prognostic biomarker for clinical outcomes of ccRCC patients, and two nomograms with IDH1 are potential effective prognostic models for ccRCC.

Evolving Treatment Strategies for Elderly Leukemia Patients with IDH Mutations

Acute myeloid leukemia (AML) is a debilitating and life-threatening condition, especially for elderly patients who account for over 50% of diagnoses. For over four decades, standard induction therapy with intensive cytotoxic chemotherapy for AML had remained unchanged. However, for most patients, standard therapy continues to have its shortcomings, especially for elderly patients who may not be able to tolerate the complications from intensive cytotoxic chemotherapy. New research into the development of targeted and alternative therapies has led to a new era in AML therapy. For the nearly 20% of diagnoses harboring a mutation in isocitrate dehydrogenase 1 or 2 (IDH1/2), potential treatment options have undergone a paradigm shift away from intensive cytotoxic chemotherapy and towards targeted therapy alone or in combination with lower intensity chemotherapy. The first FDA approved IDH2 inhibitor was enasidenib in 2017. In addition, IDH1 inhibitors are in ongoing clinical studies, and the oral BCL-2 inhibitor venetoclax shows preliminary efficacy in this subset of patients. These new tools aim to improve outcomes and change the treatment paradigm for elderly patients with IDH mutant AML. However, the challenge of how to best incorporate these agents into standard practice remains.

The role of compartmentalized signaling pathways in the control of mitochondrial activities in cancer cells

Mitochondria are the powerhouse organelles present in all eukaryotic cells. They play a fundamental role in cell respiration, survival and metabolism. Stimulation of G-protein coupled receptors (GPCRs) by dedicated ligands and consequent activation of the cAMP·PKA pathway finely couple energy production and metabolism to cell growth and survival. Compartmentalization of PKA signaling at mitochondria by A-Kinase Anchor Proteins (AKAPs) ensures efficient transduction of signals generated at the cell membrane to the organelles, controlling important aspects of mitochondrial biology. Emerging evidence implicates mitochondria as essential bioenergetic elements of cancer cells that promote and support tumor growth and metastasis. In this context, mitochondria provide the building blocks for cellular organelles, cytoskeleton and membranes, and supply all the metabolic needs for the expansion and dissemination of actively replicating cancer cells. Functional interference with mitochondrial activity deeply impacts on cancer cell survival and proliferation. Therefore, mitochondria represent valuable targets of novel therapeutic approaches for the treatment of cancer patients. Understanding the biology of mitochondria, uncovering the molecular mechanisms regulating mitochondrial activity andmapping the relevant metabolic and signaling networks operating in cancer cells will undoubtly contribute to create a molecular platform to be used for the treatment of proliferative disorders. Here, we will highlight the emerging roles of signaling pathways acting downstream to GPCRs and their intersection with the ubiquitin proteasome system in the control of mitochondrial activity in different aspects of cancer cell biology.