ABSTRACT
IDH1 mutations are common in low-grade gliomas and secondary glioblastomas and cause overproduction of (R)-2HG. (R)-2HG modulates the activity of many enzymes, including some that are linked to transformation and some that are probably bystanders. Although prior work on (R)-2HG targets focused on 2OG-dependent dioxygenases, we found that (R)-2HG potently inhibits the 2OG-dependent transaminases BCAT1 and BCAT2, likely as a bystander effect, thereby decreasing glutamate levels and increasing dependence on glutaminase for the biosynthesis of glutamate and one of its products, glutathione. Inhibiting glutaminase specifically sensitized IDH mutant glioma cells to oxidative stress in vitro and to radiation in vitro and in vivo. These findings highlight the complementary roles for BCATs and glutaminase in glutamate biosynthesis, explain the sensitivity of IDH mutant cells to glutaminase inhibitors, and suggest a strategy for maximizing the effectiveness of such inhibitors against IDH mutant gliomas.
Subject(s)
Glioma/metabolism , Glutamic Acid/biosynthesis , Transaminases/physiology , Cell Line, Tumor , Glioma/physiopathology , Glutamic Acid/drug effects , Glutarates/metabolism , Glutarates/pharmacology , Homeostasis/drug effects , Humans , Isocitrate Dehydrogenase/genetics , Isocitrate Dehydrogenase/physiology , Minor Histocompatibility Antigens/genetics , Minor Histocompatibility Antigens/physiology , Mutation , Oxidation-Reduction/drug effects , Pregnancy Proteins/genetics , Pregnancy Proteins/physiology , Transaminases/antagonists & inhibitors , Transaminases/geneticsABSTRACT
A recent study (Sulkowski et al., 2020) reveals that oncometabolites, which are produced by metabolic gene mutations in many cancers, sensitize cells to PARP inhibition by antagonizing histone demethylation and obscuring epigenetic marks that are necessary for efficient DNA repair.
Subject(s)
DNA Damage , Neoplasms/genetics , DNA Repair , Epigenesis, Genetic , Epigenomics , HumansABSTRACT
In recent years, the classification of adult-type diffuse gliomas has undergone a revolution, wherein specific molecular features now represent defining diagnostic criteria of IDH-wild-type glioblastomas, IDH-mutant astrocytomas, and IDH-mutant 1p/19q-codeleted oligodendrogliomas. With the introduction of the 2021 WHO CNS classification, additional molecular alterations are now integrated into the grading of these tumors, given equal weight to traditional histologic features. However, there remains a great deal of heterogeneity in patient outcome even within these established tumor subclassifications that is unexplained by currently codified molecular alterations, particularly in the IDH-mutant astrocytoma category. There is also significant intercellular genetic and epigenetic heterogeneity and plasticity with resulting phenotypic heterogeneity, making these tumors remarkably adaptable and robust, and presenting a significant barrier to the design of effective therapeutics. Herein, we review the mechanisms and consequences of genetic and epigenetic instability, including chromosomal instability (CIN), microsatellite instability (MSI)/mismatch repair (MMR) deficits, and epigenetic instability, in the underlying biology, tumorigenesis, and progression of IDH-mutant astrocytomas. We also discuss the contribution of recent high-resolution transcriptomics studies toward defining tumor heterogeneity with single-cell resolution. While intratumoral heterogeneity is a well-known feature of diffuse gliomas, the contribution of these various processes has only recently been considered as a potential driver of tumor aggressiveness. CIN has an independent, adverse effect on patient survival, similar to the effect of histologic grade and homozygous CDKN2A deletion, while MMR mutation is only associated with poor overall survival in univariate analysis but is highly correlated with higher histologic/molecular grade and other aggressive features. These forms of genomic instability, which may significantly affect the natural progression of these tumors, response to therapy, and ultimately clinical outcome for patients, are potentially measurable features which could aid in diagnosis, grading, prognosis, and development of personalized therapeutics.
Subject(s)
Astrocytoma , Brain Neoplasms , Disease Progression , Epigenesis, Genetic , Isocitrate Dehydrogenase , Mutation , Humans , Brain Neoplasms/genetics , Brain Neoplasms/pathology , Astrocytoma/genetics , Astrocytoma/pathology , Isocitrate Dehydrogenase/genetics , Mutation/genetics , Epigenesis, Genetic/geneticsABSTRACT
PURPOSE: Since the discovery of IDH mutations in glioma over a decade ago, significant progress has been made in determining how these mutations affect epigenetic, transcriptomic, and metabolic programs in brain tumor cells. In this article, we summarize current understanding of how IDH mutations influence DNA damage in glioma and discuss clinical implications of these findings. METHODS: We performed a thorough review of peer-reviewed publications and provide an overview of key mechanisms by which IDH mutations impact response to DNA damage in gliomas, with an emphasis on clinical implications. RESULTS: The effects of mutant IDH on DNA damage largely fall into four overarching categories: Gene Expression, Sensitivity to Alkylating Agents, Homologous Recombination, and Oxidative Stress. From a mechanistic standpoint, we discuss how mutant IDH and the oncometabolite (R)-2HG affect each of these categories of DNA damage. We also contextualize these mechanisms with respect to ongoing clinical trials. Studies are underway that incorporate current standard-of-care therapies, including radiation and alkylating agents, in addition to novel therapeutic agents that exert genotoxic stress specifically in IDH-mutant gliomas. Lastly, we discuss key unanswered questions and emerging data in this field that have important implications for our understanding of glioma biology and for the development of new brain tumor therapies. CONCLUSION: Mounting preclinical and clinical data suggest that IDH mutations alter DNA damage sensing and repair pathways through distinct mechanisms. Future studies are needed to deepen our understanding of these processes and provide additional mechanistic insights that can be leveraged for therapeutic benefit.
Subject(s)
Brain Neoplasms , Glioma , Humans , Glioma/genetics , DNA Damage , Mutation , Brain Neoplasms/genetics , Brain Neoplasms/therapy , Isocitrate Dehydrogenase/geneticsABSTRACT
Current systems for modulating the abundance of proteins of interest in living cells are powerful tools for studying protein function but differ in terms of their complexity and ease of use. Moreover, no one system is ideal for all applications, and the best system for a given protein of interest must often be determined empirically. The thalidomide-like molecules (collectively called the IMiDs) bind to the ubiquitously expressed cereblon ubiquitin ligase complex and alter its substrate specificity such that it targets the IKZF1 and IKZF3 lymphocyte transcription factors for destruction. Here, we mapped the minimal IMiD-responsive IKZF3 degron and show that this peptidic degron can be used to target heterologous proteins for destruction with IMiDs in a time- and dose-dependent manner in cultured cells grown ex vivo or in vivo.
Subject(s)
Peptides/metabolism , Proteins/metabolism , Thalidomide/analogs & derivatives , Animals , Blood-Brain Barrier , Ikaros Transcription Factor/metabolism , Mice , Proteolysis , Thalidomide/pharmacokinetics , Thalidomide/pharmacology , Trans-Activators/metabolism , Ubiquitin-Protein Ligase Complexes/metabolism , UbiquitinationABSTRACT
Inactivation of the retinoblastoma gene (RB1) product, pRB, is common in many human cancers. Targeting downstream effectors of pRB that are central to tumorigenesis is a promising strategy to block the growth of tumors harboring loss-of-function RB1 mutations. One such effector is retinoblastoma-binding protein 2 (RBP2, also called JARID1A or KDM5A), which encodes an H3K4 demethylase. Binding of pRB to RBP2 has been linked to the ability of pRB to promote senescence and differentiation. Importantly, genetic ablation of RBP2 is sufficient to phenocopy pRB's ability to induce these cellular changes in cell culture experiments. Moreover, germline Rbp2 deletion significantly impedes tumorigenesis in Rb1+/- mice. The value of RBP2 as a therapeutic target in cancer, however, hinges on whether loss of RBP2 could block the growth of established tumors as opposed to simply delaying their onset. Here we show that conditional, systemic ablation of RBP2 in tumor-bearing Rb1+/- mice is sufficient to slow tumor growth and significantly extend survival without causing obvious toxicity to the host. These findings show that established Rb1-null tumors require RBP2 for growth and further credential RBP2 as a therapeutic target in human cancers driven by RB1 inactivation.
Subject(s)
DNA-Binding Proteins/physiology , Histone Code/physiology , Jumonji Domain-Containing Histone Demethylases/physiology , Molecular Targeted Therapy/methods , Neoplasm Proteins/physiology , Pituitary Neoplasms/enzymology , Retinoblastoma Protein/deficiency , Thyroid Neoplasms/enzymology , Alleles , Animals , DNA-Binding Proteins/deficiency , DNA-Binding Proteins/genetics , Echocardiography , Enzyme Activation/drug effects , Fibroblasts , Genes, Retinoblastoma , Heart Septal Defects/genetics , Histone Code/drug effects , Integrases/drug effects , Jumonji Domain-Containing Histone Demethylases/deficiency , Jumonji Domain-Containing Histone Demethylases/genetics , Mice , Mice, Inbred C57BL , Pituitary Neoplasms/genetics , Pituitary Neoplasms/therapy , Recombinant Fusion Proteins/biosynthesis , Recombinant Fusion Proteins/genetics , Tamoxifen/pharmacology , Thyroid Neoplasms/genetics , Thyroid Neoplasms/therapy , Transgenes/drug effectsABSTRACT
Multiple myeloma is one of numerous malignancies characterized by increased glucose consumption, a phenomenon with significant prognostic implications in this disease. Few studies have focused on elucidating the molecular underpinnings of glucose transporter (GLUT) activation in cancer, knowledge that could facilitate identification of promising therapeutic targets. To address this issue, we performed gene expression profiling studies involving myeloma cell lines and primary cells as well as normal lymphocytes to uncover deregulated GLUT family members in myeloma. Our data demonstrate that myeloma cells exhibit reliance on constitutively cell surface-localized GLUT4 for basal glucose consumption, maintenance of Mcl-1 expression, growth, and survival. We also establish that the activities of the enigmatic transporters GLUT8 and GLUT11 are required for proliferation and viability in myeloma, albeit because of functionalities probably distinct from whole-cell glucose supply. As proof of principle regarding the therapeutic potential of GLUT-targeted compounds, we include evidence of the antimyeloma effects elicited against both cell lines and primary cells by the FDA-approved HIV protease inhibitor ritonavir, which exerts a selective off-target inhibitory effect on GLUT4. Our work reveals critical roles for novel GLUT family members and highlights a therapeutic strategy entailing selective GLUT inhibition to specifically target aberrant glucose metabolism in cancer.
Subject(s)
Glucose Transport Proteins, Facilitative/physiology , Glucose Transporter Type 4/physiology , Molecular Targeted Therapy , Multiple Myeloma/genetics , Multiple Myeloma/therapy , Biological Availability , Cell Line, Tumor , Cell Proliferation , Cell Survival/genetics , Cells, Cultured , Disease Progression , Drug Evaluation, Preclinical , Gene Expression Regulation, Neoplastic/drug effects , Gene Expression Regulation, Neoplastic/physiology , Glucose/metabolism , Glucose/pharmacokinetics , Glucose Transport Proteins, Facilitative/antagonists & inhibitors , Glucose Transport Proteins, Facilitative/genetics , Glucose Transport Proteins, Facilitative/metabolism , Glucose Transporter Type 4/antagonists & inhibitors , Glucose Transporter Type 4/genetics , Glucose Transporter Type 4/metabolism , HIV Protease Inhibitors/pharmacology , Humans , Molecular Targeted Therapy/methods , Molecular Targeted Therapy/trends , Multiple Myeloma/metabolism , Multiple Myeloma/pathology , Off-Label Use , Primary Cell Culture , Ritonavir/pharmacologyABSTRACT
Gliomas are the most common primary brain tumor and are uniformly lethal. Despite significant advancements in understanding the genetic landscape of gliomas, standard-of-care has remained largely unchanged. Subsets of gliomas are defined by gain-of-function mutations in the metabolic genes encoding isocitrate dehydrogenase (IDH). Efforts to exploit mutant IDH activity and/or directly inhibit it with mutant IDH inhibitors have been the focus of over a decade of research. The recently published INDIGO trial, demonstrating the benefit of the mutant IDH inhibitor vorasidenib in patients with low-grade IDH-mutant gliomas, introduces a new era of precision medicine in brain tumors that is poised to change standard-of-care. In this review, we highlight and contextualize the results of the INDIGO trial and introduce key questions whose answers will guide how mutant IDH inhibitors may be used in the clinic. We discuss possible combination therapies with mutant IDH inhibition and future directions for clinical and translational research.
ABSTRACT
Purpose: Despite significant advances in the treatment paradigm for patients with metastatic melanoma, melanoma brain metastasis (MBM) continues to represent a significant treatment challenge. The study of MBM is limited, in part, by shortcomings in existing preclinical models. Surgically eXplanted Organoids (SXOs) are ex vivo, three-dimensional cultures prepared from primary tissue samples with minimal processing that recapitulate genotypic and phenotypic features of parent tumors and are grown without artificial extracellular scaffolding. We aimed to develop the first matched patient-derived SXO and cell line models of MBM to investigate responses to targeted therapy. Methods: MBM SXOs were created by a novel protocol incorporating techniques for establishing glioma and cutaneous melanoma organoids. A BRAFV600K-mutant and BRAF-wildtype MBM sample were collected directly from the operating room for downstream experiments. Organoids were cultured in an optimized culture medium without an artificial extracellular scaffold. Concurrently, matched patient-derived cell lines were created. Drug screens were conducted to assess treatment response in SXOs and cell lines. Results: Organoid growth was observed within 3-4 weeks, and MBM SXOs retained histological features of the parent tissue, including pleomorphic epithelioid cells with abundant cytoplasm, large nuclei, focal melanin accumulation, and strong SOX10 positivity. After sufficient growth, organoids could be manually parcellated to increase the number of replicates. Matched SXOs and cell lines demonstrated sensitivity to BRAF and MEK inhibitors. Conclusion: Here, we describe the creation of a scaffold-free organoid model of MBM. Further study using SXOs may improve the translational relevance of preclinical studies and enable the study of the metastatic melanoma tumor microenvironment.
ABSTRACT
Isocitrate dehydrogenase 1 (IDH1) is the most commonly mutated metabolic gene across human cancers. Mutant IDH1 (mIDH1) generates the oncometabolite (R)-2-hydroxyglutarate, disrupting enzymes involved in epigenetics and other processes. A hallmark of IDH1-mutant solid tumors is T cell exclusion, whereas mIDH1 inhibition in preclinical models restores antitumor immunity. Here, we define a cell-autonomous mechanism of mIDH1-driven immune evasion. IDH1-mutant solid tumors show selective hypermethylation and silencing of the cytoplasmic double-stranded DNA (dsDNA) sensor CGAS, compromising innate immune signaling. mIDH1 inhibition restores DNA demethylation, derepressing CGAS and transposable element (TE) subclasses. dsDNA produced by TE-reverse transcriptase (TE-RT) activates cGAS, triggering viral mimicry and stimulating antitumor immunity. In summary, we demonstrate that mIDH1 epigenetically suppresses innate immunity and link endogenous RT activity to the mechanism of action of a US Food and Drug Administration-approved oncology drug.
Subject(s)
Immune Evasion , Immunity, Innate , Isocitrate Dehydrogenase , Neoplasms , Animals , Humans , Mice , Cell Line, Tumor , DNA/metabolism , DNA Demethylation , DNA Methylation , DNA Transposable Elements , Epigenesis, Genetic , Glutarates/metabolism , Immunity, Innate/genetics , Isocitrate Dehydrogenase/genetics , Isocitrate Dehydrogenase/metabolism , Mutation , Neoplasms/immunology , Neoplasms/genetics , Nucleotidyltransferases/genetics , Tumor Escape , Immune Evasion/geneticsABSTRACT
Nucleotides are substrates for multiple anabolic pathways, most notably DNA and RNA synthesis. Since nucleotide synthesis inhibitors began to be used for cancer therapy in the 1950s, our understanding of how nucleotides function in tumor cells has evolved, prompting a resurgence of interest in targeting nucleotide metabolism for cancer therapy. In this review, we discuss recent advances that challenge the idea that nucleotides are mere building blocks for the genome and transcriptome and highlight ways that these metabolites support oncogenic signaling, stress resistance, and energy homeostasis in tumor cells. These findings point to a rich network of processes sustained by aberrant nucleotide metabolism in cancer and reveal new therapeutic opportunities.
Subject(s)
Neoplasms , Nucleotides , Humans , Nucleotides/metabolism , Nucleotides/therapeutic use , Neoplasms/drug therapy , Neoplasms/genetics , DNAABSTRACT
Lower-grade gliomas exhibit a high prevalence of isocitrate dehydrogenase 1 (IDH1) mutations, but faithful models for studying these tumors are lacking. Here, we present a protocol to establish a genetically engineered mouse (GEM) model of grade 3 astrocytoma driven by the Idh1R132H oncogene. We describe steps for breeding compound transgenic mice and intracranially delivering adeno-associated virus particles, followed by post-surgical surveillance via magnetic resonance imaging. This protocol enables the generation and use of a GEM to study lower-grade IDH-mutant gliomas. For complete details on the use and execution of this protocol, please refer to Shi et al. (2022).1.
ABSTRACT
Models for human gliomas prove critical not only to advancing our understanding of glioma biology but also to facilitate the development of therapeutic modalities. Specifically, creating lower-grade glioma (LGG) models has been challenging, contributing to few investigations and the minimal progress in standard treatment over the past decade. In order to reliably predict and validate the efficacies of novel treatments, however, LGG models need to adhere to specific standards that recapitulate tumor genetic aberrations and micro-environment. This underscores the need to revisit existing models of LGG and explore prospective models that may bridge the gap between preclinical insights and clinical translation. This review first outlines a set of criteria aimed to address the current challenges hindering model development. We then evaluate the strengths and weaknesses of existing preclinical models of LGG with respect to these established standards. To conclude, the review discusses potential future directions for integrating existing models to maximize the exploration of disease mechanisms and therapeutics development.
ABSTRACT
Purpose: Metabolism within the tumor microenvironment (TME) represents an increasing area of interest to understand glioma initiation and progression. Stable isotope tracing is a technique critical to the study of tumor metabolism. Cell culture models of this disease are not routinely cultured under physiologically relevant nutrient conditions and do not retain cellular heterogeneity present in the parental TME. Moreover, in vivo, stable isotope tracing in intracranial glioma xenografts, the gold standard for metabolic investigation, is time consuming and technically challenging. To provide insights into glioma metabolism in the presence of an intact TME, we performed stable isotope tracing analysis of patient-derived, heterocellular Surgically eXplanted Organoid (SXO) glioma models in human plasma-like medium (HPLM). Methods: Glioma SXOs were established and cultured in conventional media or transitioned to HPLM. We evaluated SXO cytoarchitecture and histology, then performed spatial transcriptomic profiling to identify cellular populations and differential gene expression patterns. We performed stable isotope tracing with 15N2-glutamine to evaluate intracellular metabolite labeling patterns. Results: Glioma SXOs cultured in HPLM retain cytoarchitecture and cellular constituents. Immune cells in HPLM-cultured SXOs demonstrated increased transcription of immune-related signatures, including innate immune, adaptive immune, and cytokine signaling programs. 15N isotope enrichment from glutamine was observed in metabolites from diverse pathways, and labeling patterns were stable over time. Conclusion: To enable ex vivo, tractable investigations of whole tumor metabolism, we developed an approach to conduct stable isotope tracing in glioma SXOs cultured under physiologically relevant nutrient conditions. Under these conditions, SXOs maintained viability, composition, and metabolic activity while exhibiting increased immune-related transcriptional programs.
ABSTRACT
Background: Mutations in mismatch repair (MMR) genes (MSH2, MSH6, MLH1, and PMS2) are associated with microsatellite instability and a hypermutator phenotype in numerous systemic cancers, and germline MMR mutations have been implicated in multi-organ tumor syndromes. In gliomas, MMR mutations can function as an adaptive response to alkylating chemotherapy, although there are well-documented cases of germline and sporadic mutations, with detrimental effects on patient survival. Methods: The clinical, pathologic, and molecular features of 18 IDH-mutant astrocytomas and 20 IDH-wild-type glioblastomas with MMR mutations in the primary tumor were analyzed in comparison to 361 IDH-mutant and 906 IDH-wild-type tumors without MMR mutations. In addition, 12 IDH-mutant astrocytomas and 18 IDH-wild-type glioblastomas that developed MMR mutations between initial presentation and tumor recurrence were analyzed in comparison to 50 IDH-mutant and 104 IDH-wild-type cases that remained MMR-wild-type at recurrence. Results: In both IDH-mutant astrocytoma and IDH-wild-type glioblastoma cohorts, the presence of MMR mutation in primary tumors was associated with significantly higher tumor mutation burden (TMB) (Pâ <â .0001); however, MMR mutations only resulted in worse overall survival in the IDH-mutant astrocytomas (Pâ =â .0069). In addition, gain of MMR mutation between the primary and recurrent surgical specimen occurred more frequently with temozolomide therapy (Pâ =â .0073), and resulted in a substantial increase in TMB (Pâ <â .0001), higher grade (Pâ =â .0119), and worse post-recurrence survival (Pâ =â .0022) in the IDH-mutant astrocytoma cohort. Conclusions: These results suggest that whether present initially or in response to therapy, MMR mutations significantly affect TMB but appear to only influence the clinical outcome in IDH-mutant astrocytoma subsets.
ABSTRACT
Isocitrate dehydrogenase (IDH) is a key enzyme in normal metabolism and homeostasis. However, mutant forms of IDH are also defining features of a subset of diffuse gliomas. In this review, we highlight current techniques targeting IDH-mutated gliomas and summarize current and completed clinical trials exploring these strategies. We discuss clinical data from peptide vaccines, mutant IDH (mIDH) inhibitors, and PARP inhibitors. Peptide vaccines have the unique advantage of targeting the specific epitope of a patient's tumor, inducing a highly tumor-specific CD4+ T-cell response. mIDH-inhibitors, on the other hand, specifically target mutant IDH proteins in cancer cell metabolism and thus help halt gliomagenesis. We also explore PARP inhibitors and their role in treating diffuse gliomas, which exploit IDH-mutant diffuse gliomas by allowing the persistence of unrepaired DNA complexes. We summarize various completed and current trials targeting IDH1 and IDH2 mutations in diffuse gliomas. Therapies targeting mutant IDH have significant promise in treating progressive or recurrent IDH-mutant gliomas and may significantly change treatment paradigms in the next decade.
ABSTRACT
Oncogenic mutations in isocitrate dehydrogenase 1 (IDH1) and IDH2 occur in a wide range of cancers, including acute myeloid leukemia (AML) and glioma. Mutant IDH enzymes convert 2-oxoglutarate (2OG) to (R)-2-hydroxyglutarate [(R)-2HG], an oncometabolite that is hypothesized to promote cellular transformation by dysregulating 2OG-dependent enzymes. The only (R)-2HG target that has been convincingly shown to contribute to transformation by mutant IDH is the myeloid tumor suppressor TET2. However, there is ample evidence to suggest that (R)-2HG has other functionally relevant targets in IDH-mutant cancers. Here, we show that (R)-2HG inhibits KDM5 histone lysine demethylases and that this inhibition contributes to cellular transformation in IDH-mutant AML and IDH-mutant glioma. These studies provide the first evidence of a functional link between dysregulation of histone lysine methylation and transformation in IDH-mutant cancers. SIGNIFICANCE: Mutant IDH is known to induce histone hypermethylation. However, it is not known if this hypermethylation is functionally significant or is a bystander effect of (R)-2HG accumulation in IDH-mutant cells. Here, we provide evidence that KDM5 inhibition by (R)-2HG contributes to mutant IDH-mediated transformation in AML and glioma. This article is highlighted in the In This Issue feature, p. 1275.
Subject(s)
Glioma , Leukemia, Myeloid, Acute , Humans , Histones/metabolism , Histone Demethylases/genetics , Mutation , Glutarates , Cell Transformation, Neoplastic/genetics , Leukemia, Myeloid, Acute/genetics , Leukemia, Myeloid, Acute/pathology , Glioma/genetics , DNA Methylation , Isocitrate Dehydrogenase/genetics , Isocitrate Dehydrogenase/metabolismABSTRACT
Glioblastoma (GBM) is an aggressive adult brain cancer with few treatment options due in part to the challenges of identifying brain-penetrant drugs. Here, we investigated the mechanism of MM0299, a tetracyclic dicarboximide with anti-glioblastoma activity. MM0299 inhibits lanosterol synthase (LSS) and diverts sterol flux away from cholesterol into a "shunt" pathway that culminates in 24(S),25-epoxycholesterol (EPC). EPC synthesis following MM0299 treatment is both necessary and sufficient to block the growth of mouse and human glioma stem-like cells by depleting cellular cholesterol. MM0299 exhibits superior selectivity for LSS over other sterol biosynthetic enzymes. Critical for its application in the brain, we report an MM0299 derivative that is orally bioavailable, brain-penetrant, and induces the production of EPC in orthotopic GBM tumors but not normal mouse brain. These studies have implications for the development of an LSS inhibitor to treat GBM or other neurologic indications.
Subject(s)
Glioblastoma , Glioma , Adult , Humans , Lanosterol/pharmacology , Lanosterol/metabolism , Brain/metabolism , Glioma/drug therapy , Glioma/metabolism , Cholesterol , Glioblastoma/drug therapyABSTRACT
Metabolic dysregulation is a prominent feature in breast cancer, but it remains poorly characterized in patient tumors. In this study, untargeted metabolomics analysis of triple-negative breast cancer (TNBC) and patient with estrogen receptor (ER)-positive breast cancer samples, as well as TNBC patient-derived xenografts (PDX), revealed two major metabolic groups independent of breast cancer histologic subtypes: a "Nucleotide/Carbohydrate-Enriched" group and a "Lipid/Fatty Acid-Enriched" group. Cell lines grown in vivo more faithfully recapitulated the metabolic profiles of patient tumors compared with those grown in vitro. Integrated metabolic and gene expression analyses identified genes that strongly correlate with metabolic dysregulation and predict patient prognosis. As a proof of principle, targeting Nucleotide/Carbohydrate-Enriched TNBC cell lines or PDX xenografts with a pyrimidine biosynthesis inhibitor or a glutaminase inhibitor led to therapeutic efficacy. In multiple in vivo models of TNBC, treatment with the pyrimidine biosynthesis inhibitor conferred better therapeutic outcomes than chemotherapeutic agents. This study provides a metabolic stratification of breast tumor samples that can guide the selection of effective therapeutic strategies targeting breast cancer subsets. In addition, we have developed a public, interactive data visualization portal (http://brcametab.org) based on the data generated from this study to facilitate future research. SIGNIFICANCE: A multiomics strategy that integrates metabolic and gene expression profiling in patient tumor samples and animal models identifies effective pharmacologic approaches to target rapidly proliferating breast tumor subtypes.
Subject(s)
Cell Proliferation/drug effects , Gene Expression Profiling/methods , Metabolomics/methods , Molecular Targeted Therapy/methods , Triple Negative Breast Neoplasms/genetics , Animals , Antineoplastic Agents/pharmacology , Antineoplastic Combined Chemotherapy Protocols/pharmacology , Biphenyl Compounds/pharmacology , Carboplatin/administration & dosage , Cell Line, Tumor , Cell Proliferation/genetics , Humans , Mice, Inbred BALB C , Mice, Inbred NOD , Mice, Knockout , Mice, SCID , Paclitaxel/administration & dosage , Signal Transduction/drug effects , Signal Transduction/genetics , Triple Negative Breast Neoplasms/metabolism , Triple Negative Breast Neoplasms/pathology , Xenograft Model Antitumor Assays/methodsABSTRACT
Chromosomal instability (CIN) is a fundamental property of cancer and a key underlying mechanism of tumorigenesis and malignant progression, and has been documented in a wide variety of cancers, including colorectal carcinoma with mutations in genes such as APC. Recent reports have demonstrated that CIN, driven in part by mutations in genes maintaining overall genomic stability, is found in subsets of adult-type diffusely infiltrating gliomas of all histologic and molecular grades, with resulting elevated overall copy number burden, chromothripsis, and poor clinical outcome. Still, relatively few studies have examined the effect of this process, due in part to the difficulty of routinely measuring CIN clinically. Herein, we review the underlying mechanisms of CIN, the relationship between chromosomal instability and malignancy, the prognostic significance and treatment potential in various cancers, systemic disease, and more specifically, in diffusely infiltrating glioma subtypes. While still in the early stages of discovery compared to other solid tumor types in which CIN is a known driver of malignancy, the presence of CIN as an early factor in gliomas may in part explain the ability of these tumors to develop resistance to standard therapy, while also providing a potential molecular target for future therapies.