Biology subjects

Mathews, T. P.

Publications and source records attributed to Mathews, T. P..

At least 19 recordsLinked to original sources

bioRxiv2026

Choline Kinase Alpha Inhibition is a Mutation Agnostic Therapeutic Vulnerability in Clonal Hematopoiesis

Clonal Hematopoiesis (CH) affects the aging population and is associated with increased risk of hematological malignancy, cardiovascular disease, and all-cause mortality. Therapeutic options for CH remain limited. Using hematopoietic stem and progenitor cell (HSPC) color barcoding and mosaic mutagenesis in zebrafish, we identified perturbed choline metabolism and increased phosphatidylcholine (PC) biosynthesis via choline kinase alpha (CHKA) in asxl1-mutant HSPCs. Suppressing CHKA-dependent choline flux reduced ASXL1-driven clonal expansion. This effect was conserved in a murine DNMT3A and human TET2 model. Mechanistically, CHKA- dependent choline flux controls phosphatidylcholine production that supports platelet activating factor (PAF) production. Exogenous PAF overcomes the suppressive effect of CHKA inhibition in ASXL1 and TET2 models. We isolated primary, human HSPCs from the peripheral blood of patients with endogenous ASXL1 mutations and demonstrated that perturbing PAF signaling reduces their competitive potential in an ex vivo clonal competition assay. This CHKA/PAF axis is conserved in TET2-mutant HSPCs. Together, these findings identify a mutation agnostic metabolic dependency across the three most common CH genotypes and demonstrate that targeting the CHKA-dependent choline flux suppresses clonal expansion.

cancer biology↗

bioRxiv2026

Glutathione Protects Hematopoietic Stem Cells from Proteotoxic Stress

Glutathione is a redox buffer, best known for preventing oxidative stress and ferroptosis, but rarely studied in stem cells. We studied glutathione function in hematopoietic stem cells (HSCs) by deleting the glutamate-cysteine ligase catalytic subunit (GCLC), which synthesizes glutathione, or glutathione peroxidase 4 (GPX4), which employs glutathione to prevent ferroptosis. GCLC deficiency eliminated glutathione from hematopoietic cells, severely impairing HSC function and hematopoiesis. In contrast, GPX4 deficiency did not affect HSC function and had little effect on hematopoiesis, even after vitamin E depletion, suggesting glutathione has ferroptosis-independent functions in HSCs. Consistent with this, GCLC deficiency increased reactive oxygen species levels in hematopoietic cells. But treatment with antioxidants or ferroptosis inhibitors gave little or no rescue of HSC function despite reducing ROS levels. Rather, GCLC-deficient, but not GPX4-deficient, HSCs exhibited unfolded protein accumulation, proteostatic stress, and cell death marked by elevated p53 levels and Annexin V staining. Deficiency for p53 prolonged the function of GCLC-deficient HSCs after transplantation. Glutathione is thus necessary in HSCs for proteostasis but may be dispensable for ferroptosis inhibition in vivo.

cell biology↗

bioRxiv2026

MCT1 activity defines an aggressive metabolic phenotype and therapeutic target in non-small cell lung cancer

Lactate uptake through monocarboxylate transporter 1 (MCT1) is associated with aggressive disease in non-small cell lung cancer (NSCLC), but how lactate transport supports tumor metabolism remains incompletely understood. Integrating stable isotope tracing, metabolomics, and transcriptomics across patient tumors, animal models, and cultured cells, we show that elevated lactate utilization and SLC16A1 expression correlate with worse clinical outcomes in NSCLC. Although MCT1 inhibition with AZD3965 does not significantly impair tumor growth as a monotherapy, it depletes purine-associated metabolite pools, alters redox balance, and induces a conserved transcriptional response involving MYC target dysregulation and suppression of nucleotide metabolism genes. Addition of exogenous hypoxanthine, or expression of the E. coli-derived NADH-producing enzyme soluble transhydrogenase, partially rescues the effects of MCT1 inhibition. Importantly, this metabolically compromised state sensitizes NSCLC to nucleotide-targeting chemotherapies, including pemetrexed. These findings reveal that MCT1 mediated lactate uptake sustains nucleotide homeostasis in NSCLC, and that its inhibition exposes a context-dependent vulnerability that can be leveraged to enhance chemotherapy efficacy.

cancer biology↗

bioRxiv2026

Conservation of Nuclear Receptor DAF-12 with Evidence for Ligand Diversification in Plant-Parasitic Nematodes

Plant-parasitic nematodes cause extensive crop losses that threaten global food security and create substantial economic hardship, yet strategies for their control remain limited. Although plant-parasitic nematodes have life cycles that mirror those of their free-living and animal-parasitic relatives, comparatively little is known about the signals that drive life-cycle progression. Dafachronic acids (DAs) are steroid hormones that control life cycle by activating DAF-12 nuclear receptors in Caenorhabditis elegans and animal-parasitic nematodes. To define whether an analogous pathway exists in plant-parasitic nematodes, we investigated the responsiveness of DAF-12 orthologs from six plant-parasitic nematode species to {Delta}7-DA, an endogenous DAF-12 ligand in C. elegans and several animal-parasitic nematodes. We find that whereas some plant-parasitic nematode receptors are activated by {Delta}7-DA, others are not. Structural modeling of all six ligand-binding domains, together with docking of {Delta}7-DA into each model, indicates that responsiveness is governed by a combinatorial ligand-recognition network surrounding the ligand carboxylate rather than by any single contact residue. We further demonstrate that egg and second-stage juvenile extracts from the soybean cyst nematode, Heterodera glycines, lack detectable DA but contain distinct lipophilic fractions that activate its DAF-12 ortholog. Together, these findings suggest that many plant-parasitic nematodes utilize endogenous DAF-12 ligands that are structurally distinct from DA. Uncovering modulators of this pathway could lead to new strategies to combat nematode-driven crop loss.

molecular biology↗

bioRxiv2026

Nocturnin drives mitochondrial NADP(H)/NAD(H) rhythms to regulate steroid rhythm amplitude and time metabolism

Circadian rhythms are conserved biological timekeeping mechanisms crucial for the temporal compartmentalization of metabolic processes. However, the molecular pathways by which circadian rhythms are regulated within metabolism are not fully understood. Nocturnin (NOCT) is a highly rhythmic, clock-controlled NADP(H) phosphatase that has been implicated in numerous metabolic phenotypes. While it is known that NOCT significantly impacts the cellular NADP(H) and NAD(H) pools in vitro, NOCTs impact on their concentrations and rhythmicity in vivo has not yet been established. In fact, the rhythmicity of NADH, NADP+, and NADPH have yet to be quantified in mammalian nucleated cells. Here, we determined both the whole cell and mitochondrial NAD(H) and NADP(H) rhythms in wild-type and Noct-/-mouse livers. Unexpectedly, we found a robust rhythm in the mitochondrial NADP(H)/NAD(H) ratio that is antiphase to the respective whole cell rhythm. While loss of NOCT increases the amplitude of the whole cell NADP(H)/NAD(H) rhythm, the mitochondrial rhythm is completely damped in Noct-/-mice. The constitutively higher relative NADP(H) within Noct-/-mitochondria drives steroidogenesis, leading to an increased amplitude of plasma corticosterone. Both the acute increase in plasma corticosterone and the disruption of mitochondrial cofactor rhythms caused by loss of NOCT lead to widespread changes in hepatic metabolism. Collectively, we found that NOCTs control of mitochondrial NADP(H)/NAD(H) rhythms is a novel regulator of steroid amplitude and downstream metabolic rhythms.

physiology↗

bioRxiv2026

MitoSAM-dependent lipoylation controls postnatal heart development via metabolic remodeling

The neonatal heart undergoes a rapid metabolic transition from fetal glycolysis to oxidative phosphorylation, requiring coordinated metabolic remodeling. Mechanisms driving this transition remain unclear. Here, we demonstrate that sufficient mitochondrial S-adenosylmethionine (mitoSAM), imported via the solute carrier Slc25a26, is essential for this shift by sustaining the lipoylation of 2-oxoacid dehydrogenases, critical for TCA cycle activation. Proteomic and metabolomic profiling revealed that reduced mitoSAM availability impaired lipoylation, blocking TCA cycle function and restricting nucleotide synthesis, while mitochondrial gene expression and respiratory capacity remained largely intact. In vivo EdU labeling showed persistent cardiomyocyte proliferation imposing further strain on nucleotide pools. Supplementation with medium-chain triglycerides during the suckling-to-weaning transition restored metabolic function and normalized cardiac growth and morphology. Our data reveal a critical developmental window in which mitoSAM-dependent lipoylation ensures heart maturation.

biochemistry↗

bioRxiv2026

Leptin Receptor+ cells create a perisinusoidal niche for thrombopoiesis in the bone marrow by synthesizing CXCL14

Leptin Receptor-expressing (LepR+) stromal cells in the bone marrow are a critical source of growth factors for the maintenance of hematopoietic stem cells (HSCs) and most restricted hematopoietic progenitors. An important unresolved question is whether they also regulate terminal differentiation in some hematopoietic cells. We found that LepR+ cells promote thrombopoiesis by synthesizing the chemokine CXCL14, which is expressed in the bone marrow by a subset of LepR+ cells. Cxcl14-expressing LepR+ cells extend fine processes that wrap around perisinusoidal megakaryocytes. Deletion of Cxcl14 from LepR+ cells did not significantly alter HSC function or most aspects of bone marrow hematopoiesis, including megakaryocyte generation; however, it significantly reduced the numbers of proplatelet-forming megakaryocytes in the bone marrow and platelets in the blood. CXCL14 promoted platelet formation by remodeling lipid metabolism in megakaryocytes, increasing fatty acid transporter expression and enabling megakaryocytes to take up more polyunsaturated fatty acids from circulation. A high fat diet rescued the formation of proplatelet-forming megakaryocytes and platelets in Lepr-cre; Cxcl14 fl/fl mice. CXCL14 protein was sufficient to promote platelet formation by megakaryocytes in vitro and in vivo. LepR+ cells thus create a perisinusoidal niche for thrombopoiesis by producing CXCL14, which regulates lipid metabolism and terminal differentiation in megakaryocytes. Key pointsO_LILeptin Receptor+ stromal cells regulate terminal differentiation in megakaryocytes in addition to maintaining stem and progenitor cells C_LIO_LICXCL14 from Leptin Receptor+ cells promotes the formation of platelets by remodeling lipid metabolism in megakaryocytes in the bone marrow C_LI

cell biology↗

bioRxiv2025

Gliomas phenocopy an inborn error of metabolism to drive neuronal activity and tumor growth

The metabolic hallmarks of high-grade glioma (HGG) are not fully understood. Human brain tissue metabolomics revealed that the creatine synthesis pathway intermediate guanidinoacetate (GAA) accumulated [~]100-fold in HGGs relative to controls, which was caused by imbalanced activities of enzymes in this pathway. Glioma cells secreted GAA rather than using it to produce creatine, implicating an unexpected function. GAA accumulates in GAMT deficiency, an inborn error of metabolism, and elevates neuronal excitability. Neuronal excitability is also increased in glioma and drives tumor growth through neuron-glioma interactions. We hypothesized that glioma-generated GAA excites surrounding neurons. Indeed, GAA induced neuronal hyperactivity by activating GABAA receptors and causing depolarizing GABA currents in glioma-associated neurons with dysregulated chloride homeostasis. Depleting tumoral GAA decreased electrochemical activity, neuron-glioma interactions, and tumor aggressiveness. Our findings unveil a new mechanism linking cancer metabolism with cancer neuroscience and leverage human genetics to nominate GAA synthesis as a target in gliomas.

cancer biology↗

bioRxiv2025

Mutant IDH silences GSX2 to reprogram neural progenitor cell fate and promote gliomagenesis

Isocitrate dehydrogenase (IDH) mutations arise early in gliomas and are associated with a defined neurodevelopmental cancer cell hierarchy. However, how mutant IDH contributes to this hierarchy and whether this interaction promotes gliomagenesis remain unclear. We captured the dynamics of IDH-mutant glioma initiation in genetically engineered mice through time-resolved, single-cell genomics. Mutant IDH activates and induces lineage switching of neural progenitor cells (NPCs). These actions expand oligodendrocyte precursor cells, the predominant cell-of-origin for these tumors, at the expense of interneurons. Lineage switching is mediated by promoter hypermethylation and silencing of Gsx2, a homeobox gene required for neurogenesis. Critically, Gsx2 ablation recapitulates NPC fate reprogramming by mutant IDH. We provide a new model of neural cell fate control by IDH oncogenes and insights into the developmental origins of glioma.

cancer biology↗

bioRxiv2025

Nitrogen metabolism profiling reveals cell state-specific pyrimidine synthesis pathway choice

Conventional stable isotope tracing assays track one or several metabolites. However, cells use an array of nutrients to sustain nitrogen metabolic pathways. This incongruency hampers a system level understanding of cellular nitrogen metabolism. Therefore, we created a platform to simultaneously trace 30 nitrogen isotope-labeled metabolites. This platform revealed that while primitive cells engage both de novo and salvage pyrimidine synthesis pathways, differentiated cells nearly exclusively salvage uridine despite expressing de novo pathway enzymes. This link between cell state and pyrimidine synthesis routes persisted in physiological contexts, including primary murine and human tissues and tumor xenografts. Mechanistically, we found that Ser1900 phosphorylation of CAD, the first enzyme of the de novo pathway, was enriched in primitive cells and that mimicking this modification in differentiated cells abrogated their preference for pyrimidine salvage. Collectively, we establish a method for nitrogen metabolism profiling and define a mechanism of cell state-specific pyrimidine synthesis pathway choice.

cell biology↗

bioRxiv2025

L-2-hydroxyglutarate impairs neuronal differentiation through epigenetic activation of MYC expression

High levels of L- and D-2-hydroxyglutarate, the reduced forms of -ketoglutarate (KG), are implicated in human neurodevelopmental disorders and cancer. Both enantiomers exert effects on epigenetics by modulating a family of KG-dependent dioxygenases involved in histone, DNA and RNA demethylation. L-2HG dehydrogenase (L2HGDH) converts L-2HG to KG. Its deficiency is a rare, autosomal recessive inborn error of metabolism (IEM) characterized by systemic elevations of L-2HG, progressive neurological disability and a high risk of malignancy in the brain. The mechanisms behind these aberrations are unknown. Here we used an isogenic, patient-derived induced pluripotent stem cell (iPSC) system to study the impact of L2HGDH deficiency on neural progenitor cell (NPC) function and neuronal differentiation. We demonstrate that L2HGDH deficiency causes accumulation of L-2HG, NPC hyperproliferation, increased clonogenicity, excessive growth, and defective neuronal differentiation in 2D cultures and cortical spheroids. Editing the L2HGDH locus to wild-type reverses these effects. Blocking L-2HG accumulation in NPCs with a glutaminase inhibitor also induces neuronal differentiation. L-2HG-dependent inhibition of KDM5 histone demethylases leads to widespread retention of H3K4me2 and H3K4me3, markers of active gene expression. These marks are prominently elevated at the MYC locus in L2HGDH-deficient cells, and consequently cells express high MYC both in 2D culture and in many distinct cell types within cortical spheroids. Although thousands of loci display altered histone methylation, genetically or pharmacologically normalizing MYC is sufficient to completely reverse defective neuronal differentiation. These data indicate that the primary metabolic disturbance in an iPSC IEM model activates the MYC oncogene, favoring stem cell self-renewal and suppressing lineage commitment to neurons.

genetics↗

bioRxiv2025

NAD+ Sensing by PARP7 Regulates the C/EBPβ-Dependent Transcription Program in Adipose Tissue In Vivo

We have identified PARP7, an NAD+-dependent mono(ADP-ribosyl) transferase, as a key regulator of the C/EBP{beta}-dependent proadipogenic transcription program. Moreover, PARP7 is required for efficient adipogenesis and downstream biological functions, including involution of the lactating mammary gland. PARP7 serves as a coregulator of C/EBP{beta}, and depletion of PARP7 causes a dramatic reduction in C/EBP{beta} binding across the genome. PARP7 functions as a sensor of nuclear NAD+ levels to control gene expression. At the relatively high nuclear NAD+ concentrations in undifferentiated preadipocytes, PARP7 is catalytically active for auto- mono(ADP-ribosyl)ation (autoMARylation). As nuclear NAD+ concentrations decline post- differentiation, autoMARylation decreases dramatically. AutoMARylation promotes instability of PARP7 through an E3 ligase-ubiquitin-proteasome pathway mediated by the ADP-ribose (ADPR)-binding ubiquitin E3 ligases DTX2 and RNF114. Genetic depletion of PARP7 in mice promotes a dramatic reduction in a wide array of lipids in the mammary gland fat pads and milk from lactating females, as well as a significant decrease in nicotinamide mononucleotide (NMN), a key nutrient in mothers milk. The latter is due to reduced expression of Nampt, the gene encoding NAMPT, the enzyme that produces NMN, which is a direct transcriptional target of PARP7 and C/EBP{beta}. Collectively, our results extend the biology of PARP7 to adipogenesis and perinatal health. Moreover, our results describe the molecular events that regulate these downstream biological functions.

cell biology↗

bioRxiv2025

A transcriptional biosensor reveals mechanisms of α-ketoglutarate signaling to chromatin

Alpha-ketoglutarate (KG) is required for chromatin demethylation but mechanisms controlling KG abundance in the nucleus are poorly defined. Therefore, we designed a biosensor system to monitor this metabolite pool in human cells using an KG-responsive cyanobacterial transcription factor, NtcA. We then coupled this system with a genetic screen to identify genes that regulate KG in the nucleus, defining an inter-organelle pathway in which sequential mitochondrial activities of the GPT2 transaminase and SLC25A11 transporter supply nuclear KG. Using a mouse model of GPT2 deficiency, a human inborn error of metabolism, we found that this pathway controls chromatin methylation in the developing brain. Our work provides a tool to assess KG signaling to chromatin and a framework for leveraging forward genetics to study nuclear metabolite pools.

synthetic biology↗

bioRxiv2025

NUDT5 regulates purine metabolism and thiopurine sensitivity by interacting with PPAT

Cells generate purine nucleotides through both de novo purine biosynthesis (DNPB) and purine salvage. Purine accumulation represses energetically costly DNPB through feedback inhibition of the enzymatic steps that produce the precursor phosphoribosylamine. Excessive DNPB is associated with human diseases including neurological dysfunction and hyperuricemia. However, the mechanisms explaining how cells balance DNPB and purine salvage are incompletely understood. Data from a genome-wide CRISPR loss-of-function screen and extensive stable isotope tracing identified Nudix hydrolase 5 (NUDT5) as a suppressor of DNPB during purine salvage. NUDT5 ablation allows DNPB to persist in the presence of either native purines or thiopurine drugs; this renders NUDT5-deficient cells insensitive to thiopurine treatment. Surprisingly, this regulation occurs independently of NUDT5s known function in hydrolyzing ADP-ribose to AMP and ribose-5-phosphate. Rather, NUDT5 interacts with phosphoribosyl pyrophosphate amidotransferase (PPAT), the rate-limiting enzyme in DNPB that generates phosphoribosylamine. Upon induction of purine salvage, the PPAT-NUDT5 interaction is required to trigger disassembly of the purinosome, a cytosolic metabolon involved in efficient DNPB. Mutations that disrupt NUDT5s interaction with PPAT but leave its catalytic activity intact permit excessive DNPB during purine salvage, inducing thiopurine resistance. Collectively, our findings identify NUDT5 as a regulator governing the balance between DNPB and purine salvage, underscoring its impact on nucleotide metabolism and efficacy of thiopurine treatment.

biochemistry↗

bioRxiv2024

Metabolic rewiring in fat-depleted Drosophila reveals triglyceride:glycogen crosstalk and identifies cDIP as a new regulator of energy metabolism

Tissues store nutrients as triglyceride (TG) or glycogen at specific ratios, but how these reserves are sensed and balanced remains poorly understood. Here we show that blockage of de novo lipogenesis (DNL) in the Drosophila fat body (FB) triggers a cell autonomous metabolic switch characterized by severe fat depletion and profound glycogen accumulation that supports animal development. Despite lipid loss, Drosophila develop normally but exhibit shortened lifespans and impaired female fecundity. Mechanistically, we identify SREBP-dependent metabolic rewiring that facilitates a switch from TG to glycogen storage, triggered by fatty acid deficiency when DNL is inhibited, and which is rescued by dietary fatty acids. Fat depleted FBs require glycolysis but exhibit blunted mitochondrial metabolism, and no dependence on lactate utilization. Finally, we identify histone acetyltransferases (HATs) Nej and Tip60, which support SREBP activity, as essential for this metabolic switch. Collectively, we propose that in response to DNL deficiency, the fat-depleted FB undergoes a SREBP-mediated TG-to-glycogen metabolic switch preserving organismal development at the cost of reproductive success. Key findingsO_LIFat body-specific FASN1 loss leads to fat-depleted but viable Drosophila that complete their developmental lifecycle by rewiring energy metabolism to store glycogen instead of fat C_LIO_LIFASN1-deficient larvae functionally rely on glycogen synthesis and glycolysis, but not lactate metabolism, and display blunted TCA metabolism C_LIO_LIMetabolic screening reveals a SREBP-dependent TG:glycogen metabolic switch in response to blockage of DNL fatty acid biosynthesis C_LIO_LIHistone acetyltransferases (HATs) Nej and Tip60, and acetyl-CoA synthase, are required for the TG:glycogen metabolic switch C_LI

cell biology↗

bioRxiv2024

Ascorbate depletion increases quiescence and self-renewal potential in hematopoietic stem cells and multipotent progenitors

Ascorbate (vitamin C) limits hematopoietic stem cell (HSC) function and suppresses leukemia development by promoting the function of the Tet2 tumor suppressor. In humans, ascorbate is obtained from the diet while in mice it is synthesized in the liver. In this study, we show that deletion of the Slc23a2 ascorbate transporter severely depleted ascorbate from hematopoietic cells. Slc23a2 deficiency increased HSC reconstituting potential and self-renewal potential upon transplantation into irradiated mice. Slc23a2 deficiency also increased the reconstituting and self-renewal potential of multipotent hematopoietic progenitors (MPPs), conferring the ability to long-term reconstitute irradiated mice. Slc23a2-deficient HSCs and MPPs divided much less frequently than control HSCs and MPPs. Increased self-renewal and reconstituting potential were observed particularly in quiescent Slc23a2-deficient HSCs and MPPs. The effect of Slc23a2 deficiency on MPP self-renewal was not mediated by reduced Tet2 function. Ascorbate thus regulates quiescence and restricts self-renewal potential in HSCs and MPPs such that ascorbate depletion confers MPPs with long-term self-renewal potential. KEY POINTSO_LIDeletion of the ascorbate transporter, Slc23a2, increases quiescence and self-renewal potential in HSCs and multipotent progenitors C_LIO_LIAscorbate depletion is sufficient to confer long-term self-renewal potential upon multipotent hematopoietic progenitors C_LI

cell biology↗

bioRxiv2023

Electron transport inhibition increases cellular dependence on purine transport and salvage

Cancer cells reprogram their metabolism to support cell growth and proliferation in harsh environments. While many studies have documented the importance of mitochondrial oxidative phosphorylation (OXPHOS) in tumor growth, some cancer cells experience conditions of reduced OXPHOS in vivo and induce alternative metabolic pathways to compensate. To assess how human cells respond to mitochondrial dysfunction, we performed metabolomics in fibroblasts and plasma from patients with inborn errors of mitochondrial metabolism, and in cancer cells subjected to inhibition of the electron transport chain (ETC). All these analyses revealed extensive perturbations in purine-related metabolites; in non-small cell lung cancer (NSCLC) cells, ETC blockade led to purine metabolite accumulation arising from a reduced cytosolic NAD+/NADH ratio (NADH reductive stress). Stable isotope tracing demonstrated that ETC deficiency suppressed de novo purine nucleotide synthesis while enhancing purine salvage. Analysis of NSCLC patients infused with [U-13C]glucose revealed that tumors with markers of low oxidative mitochondrial metabolism exhibited high expression of the purine salvage enzyme HPRT1 and abundant levels of the HPRT1 product inosine monophosphate (IMP). ETC blockade also induced production of ribose-5 phosphate (R5P) by the pentose phosphate pathway (PPP) and import of purine nucleobases. Blocking either HPRT1 or nucleoside transporters sensitized cancer cells to ETC inhibition, and overexpressing nucleoside transporters was sufficient to drive growth of NSCLC xenografts. Collectively, this study mechanistically delineates how cells compensate for suppressed purine metabolism in response to ETC blockade, and uncovers a new metabolic vulnerability in tumors experiencing NADH excess.

biochemistry↗

bioRxiv2022

In-vivo characterization of glutamine metabolism identifies therapeutic targets in clear cell renal cell carcinoma

Targeting metabolic vulnerabilities has been proposed as a therapeutic strategy in renal cell carcinoma (RCC). Here, we analyzed metabolism in patient-derived xenografts (tumorgrafts) from diverse forms of RCC. Tumorgrafts from VHL-mutant clear cell RCC (ccRCC) retained metabolic features of human ccRCC and engage in oxidative and reductive glutamine metabolism. We used several approaches to suppress glutamine metabolism and test the effect on tumor growth. Genetic silencing of isocitrate dehydrogenase-1 or -2 impaired reductive labeling of TCA cycle intermediates and suppressed tumor growth. Glutaminase inhibition resulted in modest growth suppression and variable effects on glutamine metabolism in vivo. Infusions with [amide-15N]glutamine revealed persistent amidotransferase activity during glutaminase inhibition, and blocking these activities with the amidotransferase inhibitor JHU-083 also reduced tumor growth. We conclude that ccRCC tumorgrafts catabolize glutamine via multiple pathways, perhaps explaining why it has been challenging to achieve therapeutic responses in patients by inhibiting glutaminase. TeaserGlutamine fuels the TCA cycle and amidotransferase pathways in clear cell renal cell carcinoma.

cancer biology↗