Pyrimidine de novo synthesis inhibition selectively blocks effector but not memory T-cell development [scRNA-Seq 10x]
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE200488 | GEO | 2023/01/10
REPOSITORIES: GEO
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Project description:Blocking pyrimidine de novo synthesis via inhibiting Dihydroorotate dehydrogenase (DHODH) is clinically used to treat autoimmunity and to prevent the growth of rapidly dividing cells including activated T-cells. We identified a previously unrecognized resistance of precursors of memory T-cells to pyrimidine starvation. While the treatment effectively blocks effector T-cells, numbers, function and transcriptional profiles of memory T-cells and their precursors remain completely unaltered. We pinpoint this effect to a narrow time-window in the early T-cell expansion phase, when developing effector, but not memory T-cells are selectively vulnerable to pyrimidine starvation. This stems from a higher proliferative pace of early effector T-cells paired with lower pyrimidine synthesis capacity compared to memory precursors. This differential sensitivity constitutes a novel, drug-targetable checkpoint that efficiently diminishes effector T-cells without harming the memory compartment. We envision that knowledge of this pyrimidine synthesis-based cell fate-determining particularity opens up new means to safely manipulate effector T-cell responses.
2023-01-10 | GSE200359 | GEO
Project description:Blocking pyrimidine de novo synthesis via inhibiting Dihydroorotate dehydrogenase (DHODH) is clinically used to treat autoimmunity and to prevent the growth of rapidly dividing cells including activated T-cells. We identified a previously unrecognized resistance of precursors of memory T-cells to pyrimidine starvation. While the treatment effectively blocks effector T-cells, numbers, function and transcriptional profiles of memory T-cells and their precursors remain completely unaltered. We pinpoint this effect to a narrow time-window in the early T-cell expansion phase, when developing effector, but not memory T-cells are selectively vulnerable to pyrimidine starvation. This stems from a higher proliferative pace of early effector T-cells paired with lower pyrimidine synthesis capacity compared to memory precursors. This differential sensitivity constitutes a novel, drug-targetable checkpoint that efficiently diminishes effector T-cells without harming the memory compartment. We envision that knowledge of this pyrimidine synthesis-based cell fate-determining particularity opens up new means to safely manipulate effector T-cell responses.
2023-01-10 | GSE200358 | GEO
Project description:Macroautophagy (hereafter, autophagy) is a process that directs the degradation of cytoplasmic material in lysosomes. In addition to its homeostatic roles, autophagy undergoes dynamic positive and negative regulation in response to multiple forms of cellular stress, thus enabling the survival of cells. However, the precise mechanisms of autophagy regulation are not fully understood. To identify potential negative regulators of autophagy, we performed a genome-wide CRISPR screen using the quantitative autophagic flux reporter GFP-LC3-RFP. We identified phosphoribosylformylglycinamidine synthase (PFAS), a component of the de novo purine synthesis pathway, as one such negative regulator of autophagy. Autophagy was activated in cells lacking PFAS or phosphoribosyl pyrophosphate amidotransferase (PPAT), another de novo purine synthesis enzyme, or treated with methotrexate when exogenous levels of purines were insufficient. Purine starvation-induced autophagy activation was concomitant with mTORC1 suppression, and was profoundly suppressed in cells deficient for TSC2, which negatively regulates mTORC1 through inhibition of RHEB, suggesting that purines regulate autophagy through the TSC-RHEB-mTORC1 signaling axis. Moreover, depletion of the pyrimidine synthesis enzymes carbamoyl-phosphate synthetase 2, aspartate transcarbamylase, and dihydroorotase (CAD) and dihydroorotate dehydrogenase (DHODH) activated autophagy as well, although mTORC1 activity was not altered by pyrimidine shortage. These results suggest a different mechanism of autophagy induction between purine and pyrimidine starvation. These findings provide novel insights into the regulation of autophagy by nucleotides and possibly the role of autophagy in nucleotide metabolism, leading to further developing anticancer strategies involving nucleotide synthesis and autophagy.
2021-05-11 | GSE164778 | GEO
Project description:Glioblastoma stem cells (GSCs) reprogram glucose metabolism by hijacking high-affinity glucose uptake to survive in a nutritionally dynamic microenvironment. Here, we trace metabolic aberrations in GSCs to link core genetic mutations in glioblastoma to dependency on de novo pyrimidine synthesis. Targeting the pyrimidine synthetic rate-limiting step enzyme CAD (carbamoyl-phosphate synthetase 2, aspartate transcarbamyolase, dihydroorotase) or the critical downstream enzyme, DHODH (dihydroorotate dehydrogenase) inhibited GSC survival, self-renewal, and in vivo tumor initiation through the depletion of the pyrimidine nucleotide supply. Mutations in EGFR or PTEN generated distinct CAD phosphorylation patterns to activate carbon influx through pyrimidine synthesis. Simultaneous abrogation of tumor-specific driver mutations and DHODH activity with clinically approved inhibitors demonstrated sustained inhibition of metabolic activity of pyrimidine synthesis and GSC tumorigenic capacity. Higher expression of pyrimidine synthesis genes portend poor prognosis of glioblastoma patients. Collectively, our results demonstrate a novel therapeutic approach of precision medicine through targeting the nexus between driver mutations and metabolic reprogramming in cancer stem cells.
2019-04-09 | GSE129438 | GEO
Project description:Children with relapsed or refractory T-cell acute lymphoblastic leukemia (T-ALL) have a poor prognosis with few therapeutic options. Multiple lines of evidence point towards the enzyme dihydroorotate dehydrogenase (DHODH) as a metabolic vulnerability in dysregulated and malignant T‑cells. DHODH catalyzes the fourth step of de novo pyrimidine nucleotide synthesis (e.g., uridine, cytidine). Therefore, inhibiting DHODH via small molecule inhibitors (DHODHi) rapidly leads to the depletion of intracellular pyrimidine pools and forces cells to rely on extracellular salvage. In the absence of sufficient salvage, this intracellular nucleotide starvation results in the inhibition of DNA and RNA synthesis, cell cycle arrest, and ultimately death. T‑lymphoblasts appear to be specifically and exquisitely sensitive to nucleotide starvation following DHODHi. We have confirmed this sensitivity in vitro as well as in vivo in three murine models of T‑ALL. Additionally, we have identified that certain subsets of T-ALL seem to have an increased reliance on oxidative phosphorylation when treated with DHODHi. Through a series of metabolic assays, we show that leukemia cells, in the setting of nucleotide starvation, have changes in their mitochondrial membrane potential and may be more highly dependent on alternative fuel sources. We hope these changes point to a metabolic vulnerability that may distinguish them from normal T-cells and other normal hematopoietic cells and offer an exploitable therapeutic opportunity. The availability of clinical-grade DHODH inhibitors currently in human clinical trials speaks to the potential for rapidly advancing this work into the clinic.
2023-12-07 | GSE216753 | GEO
Project description:Using killer cell lectin-like receptor G1 as a marker to distinguish terminal effector cells from memory precursors, we found that despite their diverse cell fates both subsets possessed remarkably similar gene expression profiles and functioned as equally potent killer cells. However, only the memory precursors were capable of making IL-2 thus defining a novel effector cell that was cytotoxic, expressed granzyme B, and produced inflammatory cytokines in addition to IL-2. This effector population then differentiated into long-lived protective memory T cells capable of self-renewal and rapid re-call responses. Mechanistic studies showed that cells that continued to receive antigenic stimulation during the later stages of infection were more likely to become terminal effectors. Importantly, curtailing antigenic stimulation towards the tail-end of the acute infection enhanced the generation of memory cells. These studies support the decreasing potential model of memory differentiation and show that the duration of antigenic stimulation is a critical regulator of memory formation Experiment Overall Design: An important question in memory development is understanding the differences between effector CD8 T cells that die versus effector cells that survive and give rise to memory cells. In this study we provide a comprehensive phenotypic, functional and genomic profiling of terminal effectors and memory precursors, towards better understanding the generation of these subsets. The two effector subsets were FACS purified during the early expansion phase (Days 4-5 post-infection) and extensively analyzed for their phenotypic (eg. CD127, CD62L, CD27, Bcl-2, Granzyme B, etc.) and functional properties (cytokine production, cytotoxicity, homeostatic proliferation, recall proliferation), and gene expression profiles (by genome-wide microarray analyses). Mechanistic studies involving the extent of proliferation and duration of antigen stimulation on memory differentiation potential of effectors were also performed using adoptive transfer techniques.
2008-06-11 | E-GEOD-10239 | biostudies-arrayexpress
Project description:MYC-driven medulloblastoma (MB) is an aggressive pediatric brain tumor characterized by therapy resistance and disease recurrence. Here we integrated data from unbiased genetic screening and metabolomic profiling to identify multiple cancer-selective metabolic vulnerabilities in MYC-driven MB tumor cells, which are amenable to therapeutic targeting. Among these targets, dihydroorotate dehydrogenase (DHODH), an enzyme that catalyzes de novo pyrimidine biosynthesis, emerged as a favorable candidate for therapeutic targeting. Mechanistically, DHODH inhibition acts on-target leading to uridine metabolite scarcity and hyperlipidemia, accompanied by reduced protein O-GlcNAcylation and c-Myc degradation. Pyrimidine starvation evokes a metabolic stress response that leads to cell cycle arrest and apoptosis. We further show that an orally available small molecule DHODH inhibitor demonstrates potent mono-therapeutic efficacy against patient-derived MB xenografts in vivo. The reprogramming of pyrimidine metabolism in MYC-driven medulloblastoma represents an unappreciated therapeutic strategy and a potential new class of treatments with stronger cancer selectivity and fewer neurotoxic sequelae.
2022-11-09 | GSE214956 | GEO
Project description:MYC-driven medulloblastoma (MB) is an aggressive pediatric brain tumor characterized by therapy resistance and disease recurrence. Here we integrated data from unbiased genetic screening and metabolomic profiling to identify multiple cancer-selective metabolic vulnerabilities in MYC-driven MB tumor cells, which are amenable to therapeutic targeting. Among these targets, dihydroorotate dehydrogenase (DHODH), an enzyme that catalyzes de novo pyrimidine biosynthesis, emerged as a favorable candidate for therapeutic targeting. Mechanistically, DHODH inhibition acts on-target leading to uridine metabolite scarcity and hyperlipidemia, accompanied by reduced protein O-GlcNAcylation and c-Myc degradation. Pyrimidine starvation evokes a metabolic stress response that leads to cell cycle arrest and apoptosis. We further show that an orally available small molecule DHODH inhibitor demonstrates potent mono-therapeutic efficacy against patient-derived MB xenografts in vivo. The reprogramming of pyrimidine metabolism in MYC-driven medulloblastoma represents an unappreciated therapeutic strategy and a potential new class of treatments with stronger cancer selectivity and fewer neurotoxic sequelae.
2022-11-09 | GSE214802 | GEO
Project description:MYC-driven medulloblastoma (MB) is an aggressive pediatric brain tumor characterized by therapy resistance and disease recurrence. Here we integrated data from unbiased genetic screening and metabolomic profiling to identify multiple cancer-selective metabolic vulnerabilities in MYC-driven MB tumor cells, which are amenable to therapeutic targeting. Among these targets, dihydroorotate dehydrogenase (DHODH), an enzyme that catalyzes de novo pyrimidine biosynthesis, emerged as a favorable candidate for therapeutic targeting. Mechanistically, DHODH inhibition acts on-target leading to uridine metabolite scarcity and hyperlipidemia, accompanied by reduced protein O-GlcNAcylation and c-Myc degradation. Pyrimidine starvation evokes a metabolic stress response that leads to cell cycle arrest and apoptosis. We further show that an orally available small molecule DHODH inhibitor demonstrates potent mono-therapeutic efficacy against patient-derived MB xenografts in vivo. The reprogramming of pyrimidine metabolism in MYC-driven medulloblastoma represents an unappreciated therapeutic strategy and a potential new class of treatments with stronger cancer selectivity and fewer neurotoxic sequelae.
2022-11-09 | GSE214801 | GEO
Project description:PTC299 was identified as an inhibitor of VEGFA mRNA translation in a phenotypic screen and evaluated in the clinic for treatment of solid tumors. To guide precision cancer treatment, we performed extensive biological characterization of the activity of PTC299 and demonstrated that inhibition of VEGF production and cell proliferation by PTC299 is linked to a decrease in uridine nucleotides by targeting dihydroorotate dehydrogenase (DHODH), a rate limiting enzyme for de novo pyrimidine nucleotide synthesis. Unlike previously reported DHODH inhibitors that were identified using in vitro enzyme assays, PTC299 is a more potent inhibitor of DHODH in isolated mitochondria suggesting that mitochondrial membrane lipid engagement in the DHODH conformation in situ is required for its optimal activity. PTC299 has broad and potent activity against hematological cancer cells in preclinical models, reflecting a reduced pyrimidine nucleotide salvage pathway in leukemia cells. Archived serum samples from patients treated with PTC299 demonstrated increased levels of dihydroorotate, the substrate of DHODH, indicating target engagement in patients. PTC299 has advantages over previously reported DHODH inhibitors, including greater potency, good oral bioavailability and lack of off-target kinase inhibition and myelosuppression, and thus may be useful for the targeted treatment of hematologic malignancies.
2018-10-16 | GSE121266 | GEO