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Cancer cells outgrowing in distant organs of metastasis rewire their metabolism to fuel on the available nutrients. While this is often considered an adaptive pressure limiting metastasis formation, some nutrients available at the metastatic site naturally or through changes in organ physiology may inherently promote metastatic growth. We find that the lung, a frequent site of metastasis, is a lipid-rich environment. Moreover, we observe that pathological conditions such as pre-metastatic niche formation and obesity further increase the availability of the fatty acid palmitate in the lung. We find that targeting palmitate processing inhibits spheroid growthin vitroand metastasis formation in lean and obese mice. Mechanistically, we discover that breast cancer cells use palmitate to synthesize acetyl-CoA in a carnitine palmitoyltransferase 1a (CPT1a)-dependent manner. Lysine acetyltransferase 2a (KAT2a), whose expression is promoted by palmitate availability, relies on the available acetyl-CoA to acetylate the NF-κB subunit p65. This favors nuclear location of p65 and activates a pro-metastatic transcriptional program. Accordingly, deletion of KAT2a phenocopies CPT1a silencingin vitroas well asin vivoand patients with breast cancer show co-expression of both proteins in metastases across palmitate-rich metastatic sites. In conclusion, we find that palmitate-rich environments foster metastasis growth by increasing p65 acetylation resulting in elevated NF-κB signaling.

Glioblastoma is a highly aggressive brain tumor for which there is no cure. The metabolic enzyme 6-Phosphofructo-2-Kinase/Fructose-2,6-Biphosphatase 4 (PFKFB4) is essential for glioblastoma stem-like cell (GSC) survival but its mode of action is unclear. Understanding the role of PFKFB4 in tumor cell survival could allow it to be leveraged in a cancer therapy. Here, we show the importance of PFKFB4 for glioblastoma growth in vivo in an orthotopic patient derived mouse model. In an evaluation of patient tumor samples of different cancer entities, PFKFB4 protein was found to be overexpressed in prostate, lung, colon, mammary and squamous cell carcinoma, with expression level correlating with tumor grade. Gene expression profiling in PFKFB4-silenced GSCs revealed a downregulation of hypoxia related genes and Western blot analysis confirmed a dramatic reduction of HIF (hypoxia inducible factor) protein levels. Through mass spectrometric analysis of immunoprecipitated PFKFB4, we identified the ubiquitin E3 ligase, F-box only protein 28 (FBXO28), as a new interaction partner of PFKFB4. We show that PFKFB4 regulates the ubiquitylation and subsequent proteasomal degradation of HIF-1α, which is mediated by the ubiquitin ligase activity of FBXO28. This newly discovered function of PFKFB4, coupled with its cancer specificity, provides a new strategy for inhibiting HIF-1α in cancer cells. ispartof: ONCOGENESIS vol:11 issue:1 ispartof: location:United States status: published

SUMMARYEnergetic stress compels cells to evolve adaptive mechanisms to maintain homeostasis. Here, we report that the negative regulators of mRNA translation initiation eukaryotic initiation factor 4E binding proteins 1/2 (4EBP1/2) are essential to promote the survival of mammalian cells and budding yeast under glucose starvation. Functionally, 4EBP1/2 inhibit fatty acid synthesis upon energetic stress via repression of Acetyl-CoA Carboxylase Alpha (ACACA) mRNA translation, sparing NADPH, to maintain intracellular redox balance. This has important relevance in cancers, as we uncovered that oncogene-transformed cells and glioma cells exploit the 4EBP1/2 regulation of ACACA expression and redox balance to combat energetic stress, thereby supporting transformation and tumorigenicity in vitro and in vivo. Clinically, high EIF4EBP1 (encoding 4EBP1) expression is associated with poor outcomes in several cancer types, including glioma. Our data reveal that 4EBP1/2 are conserved mediators of the survival response to energetic stress which are exploited by cancer cells for metabolic adaptation.

Diet can influence tumor aggressiveness. Recently in Nature, a study by Pascual et al. provided evidence that dietary palmitic acid induces an epigenetic memory by modulating particular histone methylation marks in cancer cells. This allows cancer cells to activate extracellular matrix secretion from Schwann cells of the tumor microenvironment, which ultimately potentiates metastasis initiation.

Cancer metastasis requires the transient activation of cellular programs enabling dissemination and seeding in distant organs1. Genetic, transcriptional and translational heterogeneity contributes to this dynamic process2,3. Metabolic heterogeneity has also been observed4, yet its role in cancer progression is less explored. Here we find that the loss of phosphoglycerate dehydrogenase (PHGDH) potentiates metastatic dissemination. Specifically, we find that heterogeneous or low PHGDH expression in primary tumours of patients with breast cancer is associated with decreased metastasis-free survival time. In mice, circulating tumour cells and early metastatic lesions are enriched with Phgdhlow cancer cells, and silencing Phgdh in primary tumours increases metastasis formation. Mechanistically, Phgdh interacts with the glycolytic enzyme phosphofructokinase, and the loss of this interaction activates the hexosamine-sialic acid pathway, which provides precursors for protein glycosylation. As a consequence, aberrant protein glycosylation occurs, including increased sialylation of integrin αvβ3, which potentiates cell migration and invasion. Inhibition of sialylation counteracts the metastatic ability of Phgdhlow cancer cells. In conclusion, although the catalytic activity of PHGDH supports cancer cell proliferation, low PHGDH protein expression non-catalytically potentiates cancer dissemination and metastasis formation. Thus, the presence of PHDGH heterogeneity in primary tumours could be considered a sign of tumour aggressiveness. ispartof: NATURE vol:605 issue:7911 pages:747-+ ispartof: location:England status: published

Metabolic rewiring is a hallmark of cancer that supports tumor growth, survival, and chemotherapy resistance. Although normal cells often rely on extracellular serine and glycine supply, a significant subset of cancers becomes addicted to intracellular serine/glycine synthesis, offering an attractive drug target. Previously developed inhibitors of serine/glycine synthesis enzymes did not reach clinical trials due to unfavorable pharmacokinetic profiles, implying that further efforts to identify clinically applicable drugs targeting this pathway are required. In this study, we aimed to develop therapies that can rapidly enter the clinical practice by focusing on drug repurposing, as their safety and cost-effectiveness have been optimized before. Using a yeast model system, we repurposed two compounds, sertraline and thimerosal, for their selective toxicity against serine/glycine synthesis-addicted breast cancer and T-cell acute lymphoblastic leukemia cell lines. Isotope tracer metabolomics, computational docking, enzymatic assays, and drug-target interaction studies revealed that sertraline and thimerosal inhibit serine/glycine synthesis enzymes serine hydroxymethyltransferase and phosphoglycerate dehydrogenase, respectively. In addition, we demonstrated that sertraline's antiproliferative activity was further aggravated by mitochondrial inhibitors, such as the antimalarial artemether, by causing G1-S cell-cycle arrest. Most notably, this combination also resulted in serine-selective antitumor activity in breast cancer mouse xenografts. Collectively, this study provides molecular insights into the repurposed mode-of-action of the antidepressant sertraline and allows to delineate a hitherto unidentified group of cancers being particularly sensitive to treatment with sertraline. Furthermore, we highlight the simultaneous inhibition of serine/glycine synthesis and mitochondrial metabolism as a novel treatment strategy for serine/glycine synthesis-addicted cancers. ispartof: MOLECULAR CANCER THERAPEUTICS vol:20 issue:1 pages:50-63 ispartof: location:United States status: published

Pyrroline-5-carboxylate reductase 1 (PYCR1) catalyzes the biosynthetic half-reaction of the proline cycle by reducing Δ1-pyrroline-5-carboxylate (P5C) to proline through the oxidation of NAD(P)H. Many cancers alter their proline metabolism by up-regulating the proline cycle and proline biosynthesis, and knockdowns of PYCR1 lead to decreased cell proliferation. Thus, evidence is growing for PYCR1 as a potential cancer therapy target. Inhibitors of cancer targets are useful as chemical probes for studying cancer mechanisms and starting compounds for drug discovery; however, there is a notable lack of validated inhibitors for PYCR1. To fill this gap, we performed a small-scale focused screen of proline analogs using X-ray crystallography. Five inhibitors of human PYCR1 were discovered: l-tetrahydro-2-furoic acid, cyclopentanecarboxylate, l-thiazolidine-4-carboxylate, l-thiazolidine-2-carboxylate, and N-formyl l-proline (NFLP). The most potent inhibitor was NFLP, which had a competitive (with P5C) inhibition constant of 100 μm The structure of PYCR1 complexed with NFLP shows that inhibitor binding is accompanied by conformational changes in the active site, including the translation of an α-helix by 1 Å. These changes are unique to NFLP and enable additional hydrogen bonds with the enzyme. NFLP was also shown to phenocopy the PYCR1 knockdown in MCF10A H-RASV12 breast cancer cells by inhibiting de novo proline biosynthesis and impairing spheroidal growth. In summary, we generated the first validated chemical probe of PYCR1 and demonstrated proof-of-concept for screening proline analogs to discover inhibitors of the proline cycle. ispartof: JOURNAL OF BIOLOGICAL CHEMISTRY vol:295 issue:52 pages:18316-18327 ispartof: location:United States status: published

Cancer stem-like cells (CSC) induce aggressive tumor phenotypes such as metastasis formation, which is associated with poor prognosis in triple-negative breast cancer (TNBC). Repurposing of FDA-approved drugs that can eradicate the CSC subcompartment in primary tumors may prevent metastatic disease, thus representing an effective strategy to improve the prognosis of TNBC. Here, we investigated spheroid-forming cells in a metastatic TNBC model. This strategy enabled us to specifically study a population of long-lived tumor cells enriched in CSCs, which show stem-like characteristics and induce metastases. To repurpose FDA-approved drugs potentially toxic for CSCs, we focused on pyrvinium pamoate (PP), an anthelmintic drug with documented anticancer activity in preclinical models. PP induced cytotoxic effects in CSCs and prevented metastasis formation. Mechanistically, the cell killing effects of PP were a result of inhibition of lipid anabolism and, more specifically, the impairment of anabolic flux from glucose to cholesterol and fatty acids. CSCs were strongly dependent upon activation of lipid biosynthetic pathways; activation of these pathways exhibited an unfavorable prognostic value in a cohort of breast cancer patients, where it predicted high probability of metastatic dissemination and tumor relapse. Overall, this work describes a new approach to target aggressive CSCs that may substantially improve clinical outcomes for patients with TNBC, who currently lack effective targeted therapeutic options. Significance: These findings provide preclinical evidence that a drug repurposing approach to prevent metastatic disease in TNBC exploits lipid anabolism as a metabolic vulnerability against CSCs in primary tumors.

Supplemental Digital Content is available in the text., Rationale: Endothelial cells (ECs) are highly glycolytic and generate the majority of their energy via the breakdown of glucose to lactate. At the same time, a main role of ECs is to allow the transport of glucose to the surrounding tissues. GLUT1 (glucose transporter isoform 1/Slc2a1) is highly expressed in ECs of the central nervous system (CNS) and is often implicated in blood-brain barrier (BBB) dysfunction, but whether and how GLUT1 controls EC metabolism and function is poorly understood. Objective: We evaluated the role of GLUT1 in endothelial metabolism and function during postnatal CNS development as well as at the adult BBB. Methods and Results: Inhibition of GLUT1 decreases EC glucose uptake and glycolysis, leading to energy depletion and the activation of the cellular energy sensor AMPK (AMP-activated protein kinase), and decreases EC proliferation without affecting migration. Deletion of GLUT1 from the developing postnatal retinal endothelium reduces retinal EC proliferation and lowers vascular outgrowth, without affecting the number of tip cells. In contrast, in the brain, we observed a lower number of tip cells in addition to reduced brain EC proliferation, indicating that within the CNS, organotypic differences in EC metabolism exist. Interestingly, when ECs become quiescent, endothelial glycolysis is repressed, and GLUT1 expression increases in a Notch-dependent fashion. GLUT1 deletion from quiescent adult ECs leads to severe seizures, accompanied by neuronal loss and CNS inflammation. Strikingly, this does not coincide with BBB leakiness, altered expression of genes crucial for BBB barrier functioning nor reduced vascular function. Instead, we found a selective activation of inflammatory and extracellular matrix related gene sets. Conclusions: GLUT1 is the main glucose transporter in ECs and becomes uncoupled from glycolysis during quiescence in a Notch-dependent manner. It is crucial for developmental CNS angiogenesis and adult CNS homeostasis but does not affect BBB barrier function.

SLC25A32 is a member of the solute carrier 25 family of mitochondrial transporters. SLC25A32 transports tetrahydrofolate (THF) as well as FAD into mitochondria and regulates mitochondrial one-carbon metabolism and redox balance. While it is known that cancer cells require one-carbon and FAD-dependent mitochondrial metabolism to sustain cell proliferation, the role of SLC25A32 in cancer cell growth remains unexplored. Our results indicate that the SLC25A32 gene is highly amplified in different tumors and that amplification correlates with increased mRNA expression and reduced patients´ survival. siRNA-mediated knock-down and CRISPR-mediated knock-out of SLC25A32 in cancer cells of different origins, resulted in the identification of cell lines sensitive and resistant to SLC25A32 inhibition. Mechanistically, tracing of deuterated serine revealed that SLC25A32 knock-down does not affect the mitochondrial/cytosolic folate flux as measured by Liquid Chromatography coupled Mass Spectrometry (LC-MS). Instead, SLC25A32 inhibition results in a respiratory chain dysfunction at the FAD-dependent complex II enzyme, induction of Reactive Oxygen Species (ROS) and depletion of reduced glutathione (GSH), which impairs cancer cell proliferation. Moreover, buthionine sulfoximine (BSO) treatment further sensitizes cells to ROS-mediated inhibition of cell proliferation upon SLC25A32 knock-down. Treatment of cells with the FAD precursor riboflavin and with GSH rescues cancer cell proliferation upon SLC25A32 down-regulation. Our results indicate that the reduction of mitochondrial FAD concentrations by targeting SLC25A32 has potential clinical applications as a single agent or in combination with approved cancer drugs that lead to increased oxidative stress and reduced tumor growth.

Introduction: Frailty commonly occurs in older persons, including those with breast cancer diagnoses. Methylmalonic acid (MMA), a metabolite and by-product of propionate metabolism, is known to increase significantly with aging. The relation between MMA concentrations and frailty is currently unknown. Objectives: A cross-sectional study was performed to study the association between baseline serum MMA concentrations and clinical frailty (estimated by G8 screening) in older patients with newly diagnosed breast cancer. Methods: 163 patients ≥70 years old with early-stage breast cancer were included (median age 76y). G8 screening and serum sample collection were performed at breast cancer diagnosis before any therapy was administered. MMA concentrations were measured via liquid chromatography with tandem mass spectrometry (LC-MS-MS). Results: MMA concentrations significantly increased with age (rs=0.3, p14/17 = ‘fit’, 52%): 250nM vs. 189 nM, respectively (p=.0002). Higher MMA concentrations were independently associated with abnormal G8 (Odds ratio, 1.003, 95%CI 1.0 to 1.006, p=.04) after adjusting for age and serum creatinine levels. Among the different components of G8, MMA concentrations correlated most with weight loss (rs= -0.18, p=.02), mobility (rs= -0.23, p=.002), and polypharmacy (rs= -0.22, p=.005). Conclusion: Elevated serum MMA concentrations at breast cancer diagnosis are significantly associated, not only with age but also independently with clinical frailty in older patients with early-stage breast cancer. MMA may be further evaluated as a biomarker of frailty in older persons with breast cancer. Citation Format: Qi Wu, Sigrid Hatse, Cindy Kenis, Yentl Lambrechts, Kevin Punie, Patrick Neven, Ann Smeets, Annouschka Laenen, Ana Gomes, Sarah-Maria Fendt, Hans Wildiers. PD6-03 Serum methylmalonic acid concentrations at breast cancer diagnosis strongly correlate with frailty: a retrospective cross-sectional study [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD6-03.

T cells dynamically rewire their metabolism during an immune response. We applied single-cell RNA sequencing to CD8+ T cells activated and differentiated in vitro in physiological medium to resolve these metabolic dynamics. We identify a differential time-dependent reliance of activating T cells on the synthesis versus uptake of various non-essential amino acids, which we corroborate with functional assays. We also identify metabolic genes that potentially dictate the outcome of T cell differentiation, by ranking them based on their expression dynamics. Among them, we find asparagine synthetase (Asns), whose expression peaks for effector T cells and decays toward memory formation. Disrupting these expression dynamics by ASNS overexpression promotes an effector phenotype, enhancing the anti-tumor response of adoptively transferred CD8+ T cells in a mouse melanoma model. We thus provide a resource of dynamic expression changes during CD8+ T cell activation and differentiation, and identify ASNS expression dynamics as a modulator of CD8+ T cell differentiation. ispartof: CELL REPORTS vol:41 issue:7 ispartof: location:United States status: published

The evolution of species involves changes in the timeline of key developmental programs. Among these, neuronal development is considerably prolonged in the human cerebral cortex compared with other mammals, leading to brain neoteny. Here we explore whether mitochondria influence the species-specific properties of cortical neuron maturation. By comparing human and mouse cortical neuronal maturation at high temporal and cell resolution, we found a slower pattern of mitochondria development in human cortical neurons compared with the mouse, together with lower mitochondria metabolic activity, particularly oxidative phosphorylation. Stimulation of mitochondria metabolism in human neurons resulted in accelerated maturation, leading to excitable and complex cells weeks ahead of time. Our data identify mitochondria as important regulators of the pace of neuronal development underlying human-specific features of brain evolution.

Supplemental information can be found online at https://doi.org/10.1016/j.molcel.2022.10.005, ACKNOWLEDGMENTS P.A.-M was supported by a Marie Sklodowska-Curie Actions individual fellowship and the Beug Foundation. A.V. was supported by Fonds Wetenschappelijk Onderzoek (FWO Vlaanderen). J.E.-H. was supported by an MRC studentship. J.C.A was supported by a Cancer Research UK Career Development Fellowship (C47559/A16243). S.-M.F. acknowledges funding from the European Research Council under the ERC Consolidator grant agreement no. 771486–MetaRegulation, FWO Projects, Fonds Baillet Latour, KU Leuven- FTBO/Internal Funding, Stichting Tegen Kanker and the King Baudouin Foundation. Work in the A.J.F. group was supported by a Wellcome Trust-ISSF grant, funding from Barts Charity (MGU0404), and by a Cancer Research UK Centre Grant to Barts Cancer Institute (C355/A25137). The illustrations in the graphical abstract and Figure 5F were created using BioRender.com., Inhibition of the electron transport chain (ETC) prevents the regeneration of mitochondrial NAD+, resulting in cessation of the oxidative tricarboxylic acid (TCA) cycle and a consequent dependence upon reductive carboxylation for aspartate synthesis. NAD+ regeneration alone in the cytosol can rescue the viability of ETC-deficient cells. Yet, how this occurs and whether transfer of oxidative equivalents to the mitochondrion is required remain unknown. Here, we show that inhibition of the ETC drives reversal of the mitochondrial aspartate transaminase (GOT2) as well as malate and succinate dehydrogenases (MDH2 and SDH) to transfer oxidative NAD+ equivalents into the mitochondrion. This supports the NAD+-dependent activity of the mitochondrial glutamate dehydrogenase (GDH) and thereby enables anaplerosis—the entry of glutamine-derived carbon into the TCA cycle and connected biosynthetic pathways. Thus, under impaired ETC function, the cytosolic redox state is communicated into the mitochondrion and acts as a rheostat to support GDH activity and cell viability., Marie Sklodowska-Curie Actions, Beug Foundation, Fonds Wetenschappelijk Onderzoek (FWO Vlaanderen), Cancer Research UK Career Development Fellowship (C47559/A16243), European Research Council under the ERC Consolidator grant agreement no. 771486–MetaRegulation, FWO Projects, Fonds Baillet Latour, KU Leuven- FTBO/Internal Funding, Wellcome Trust-ISSF grant, Barts Charity (MGU0404), Cancer Research UK Centre Grant to Barts Cancer Institute (C355/A25137)

To celebrate our Focus Issue, we asked a selection of researchers working on different aspects of metabolism what they are excited about and what is still to come. They discuss emerging concepts, unanswered questions, things to consider, and technologies that are enabling new discoveries, as well as developing and integrating approaches to drive the field forward. ispartof: MOLECULAR CELL vol:81 issue:18 pages:3659-3664 ispartof: location:United States status: published

Somatic ribosomal protein mutations have recently been described in cancer, yet their impact on cellular transcription and translation remains poorly understood. Here, we integrate mRNA sequencing, ribosome footprinting, polysomal RNA sequencing and mass spectrometry datasets from a mouse lymphoid cell model to characterize the T-cell acute lymphoblastic leukemia (T-ALL) associated ribosomal RPL10 R98S mutation. Surprisingly, RPL10 R98S induces changes in protein levels primarily through transcriptional rather than translation efficiency changes. Phosphoserine phosphatase (PSPH), encoding a key serine biosynthesis enzyme, was the only gene with elevated transcription and translation leading to protein overexpression. PSPH upregulation is a general phenomenon in T-ALL patient samples, associated with elevated serine and glycine levels in xenograft mice. Reduction of PSPH expression suppresses proliferation of T-ALL cell lines and their capacity to expand in mice. We identify ribosomal mutation driven induction of serine biosynthesis and provide evidence supporting dependence of T-ALL cells on PSPH., The ribosomal protein RPL10 is frequently mutated in T-cell acute lymphoblastic leukemia (T-ALL). Here, the authors show that it promotes proliferation of T-ALL cells by upregulating the serine biosynthesis enzyme phosphoserine phosphatase which in turn modulates serine and glycine metabolism.

The R98S mutation in ribosomal protein L10 (RPL10 R98S) affects 8% of pediatric T-cell acute lymphoblastic leukemia (T-ALL) cases, and was previously described to impair cellular proliferation. The current study reveals that RPL10 R98S cells accumulate reactive oxygen species which promotes mitochondrial dysfunction and reduced ATP levels, causing the proliferation defect. RPL10 R98S mutant leukemia cells can survive high oxidative stress levels via a specific increase of IRES-mediated translation of the anti-apoptotic factor B-cell lymphoma 2 (BCL-2), mediating BCL-2 protein overexpression. RPL10 R98S selective sensitivity to the clinically available Bcl-2 inhibitor Venetoclax (ABT-199) was supported by suppression of splenomegaly and the absence of human leukemia cells in the blood of T-ALL xenografted mice. These results shed new light on the oncogenic function of ribosomal mutations in cancer, provide a novel mechanism for BCL-2 upregulation in leukemia, and highlight BCL-2 inhibition as a novel therapeutic opportunity in RPL10 R98S defective T-ALL.

T cells dynamically rewire their metabolism during an immune response. We applied single-cell RNA sequencing to CD8

Cytotoxic T cells dynamically rewire their metabolism during the course of an immune response. While T-cell metabolism has been extensively studied at phenotypic endpoints of activation and differentiation, the underlying dynamics remain largely elusive. Here, we leverage on single-cell RNA-sequencing (scRNA-seq) measurements of in vitro activated and differentiated CD8+ T cells cultured in physiological media to resolve these metabolic dynamics. We find that our scRNA-seq analysis identifies most metabolic changes previously defined in in vivo experiments, such as a rewiring from an oxidative to an anabolism-promoting metabolic program during activation to an effector state, which is later reverted upon memory polarization. Importantly, our scRNA-seq data further provide a dynamic description of these changes. In this sense, our data predict a differential time-dependent reliance of CD8+ T cells on the synthesis versus uptake of various non-essential amino acids during T-cell activation, which we corroborate with additional functional in vitro experiments. We further exploit our scRNA-seq data to identify metabolic genes that could potentially dictate the outcome of T-cell differentiation, by ranking them based on their expression dynamics. Among the highest-ranked hits, we find asparagine synthetase (Asns), whose expression sharply peaks for effector CD8+ T cells and further decays towards memory polarization. We then confirm that these in vitro Asns expression dynamics are representative of an in vivo situation in a mouse model of viral infection. Moreover, we find that disrupting these expression dynamics in vitro, by depleting asparagine from the culture media, delays central-memory polarization. Accordingly, we find that preventing the decay of ASNS by stable overexpression at the protein level in vivo leads to a significant increase in effector CD8+ T-cell expansion, and a concomitant decrease in central-memory formation, in a mouse model of viral infection. This shows that ASNS expression dynamics dictate the fate of CD8+ T-cell differentiation. In conclusion, we provide a resource of dynamic expression changes during CD8+ T-cell activation and differentiation that is expected to increase our understanding of the dynamic metabolic requirements of T cells progressing along the immune response cascade.

Tumors undergo metabolic transformations to sustain uncontrolled proliferation, avoid cell death, and seed in secondary organs. An increased focus on cancer lipid metabolism has unveiled a number of mechanisms that promote tumor growth and survival, many of which are independent of classical cellular bioenergetics. These mechanisms include modulation of ferroptotic-mediated cell death, support during tumor metastasis, and interactions with the cells of the tumor microenvironment. As such, targeting lipid metabolism for anti-cancer therapies is attractive, with recent work on small-molecule inhibitors identifying compounds to target lipid metabolism. Here, we discuss these topics and identify open questions. ispartof: DEVELOPMENTAL CELL vol:56 issue:10 pages:1363-1393 ispartof: location:United States status: published

Astrocytes, the main supportive cell type of the brain, show functional impairments upon ageing and in a broad spectrum of neurological disorders. Limited access to human astroglia for pre-clinical studies has been a major bottleneck delaying our understanding of their role in brain health and disease. We demonstrate here that functionally mature human astrocytes can be generated by SOX9 overexpression for 6 days in pluripotent stem cell (PSC)-derived neural progenitor cells. Inducible (i)SOX9-astrocytes display functional properties comparable to primary human astrocytes comprising glutamate uptake, induced calcium responses and cytokine/growth factor secretion. Importantly, electrophysiological properties of iNGN2-neurons co-cultured with iSOX9-astrocytes are indistinguishable from gold-standard murine primary cultures. The high yield, fast timing and the possibility to cryopreserve iSOX9-astrocytes without losing functional properties makes them suitable for scaled-up production for high-throughput analyses. Our findings represent a step forward to an all-human iPSC-derived neural model for drug development in neuroscience and towards the reduction of animal use in biomedical research. Graphical Abstract

BNIP3 is a mitophagy receptor with context‐dependent roles in cancer, but whether and how it modulates melanoma growth in vivo remains unknown. Here, we found that elevated BNIP3 levels correlated with poorer melanoma patient’s survival and depletion of BNIP3 in B16‐F10 melanoma cells compromised tumor growth in vivo. BNIP3 depletion halted mitophagy and enforced a PHD2‐mediated downregulation of HIF‐1α and its glycolytic program both in vitro and in vivo. Mechanistically, we found that BNIP3‐deprived melanoma cells displayed increased intracellular iron levels caused by heightened NCOA4‐mediated ferritinophagy, which fostered PHD2‐mediated HIF‐1α destabilization. These effects were not phenocopied by ATG5 or NIX silencing. Restoring HIF‐1α levels in BNIP3‐depleted melanoma cells rescued their metabolic phenotype and tumor growth in vivo, but did not affect NCOA4 turnover, underscoring that these BNIP3 effects are not secondary to HIF‐1α. These results unravel an unexpected role of BNIP3 as upstream regulator of the pro‐tumorigenic HIF‐1α glycolytic program in melanoma cells., Mitophagy receptor BNIP3 facilitates skin cancer by supporting HIF1‐1α protein stability.

Hepatic fat accumulation is associated with diabetes and hepatocellular carcinoma (HCC). Here, we characterize the metabolic response that high-fat availability elicits in livers before disease development. After a short term on a high-fat diet (HFD), otherwise healthy mice showed elevated hepatic glucose uptake and increased glucose contribution to serine and pyruvate carboxylase activity compared with control diet (CD) mice. This glucose phenotype occurred independently from transcriptional or proteomic programming, which identifies increased peroxisomal and lipid metabolism pathways. HFD-fed mice exhibited increased lactate production when challenged with glucose. Consistently, administration of an oral glucose bolus to healthy individuals revealed a correlation between waist circumference and lactate secretion in a human cohort. In vitro, palmitate exposure stimulated production of reactive oxygen species and subsequent glucose uptake and lactate secretion in hepatocytes and liver cancer cells. Furthermore, HFD enhanced the formation of HCC compared with CD in mice exposed to a hepatic carcinogen. Regardless of the dietary background, all murine tumors showed similar alterations in glucose metabolism to those identified in fat exposed nontransformed mouse livers, however, particular lipid species were elevated in HFD tumor and nontumor-bearing HFD liver tissue. These findings suggest that fat can induce glucose-mediated metabolic changes in nontransformed liver cells similar to those found in HCC. Significance: With obesity-induced hepatocellular carcinoma on a rising trend, this study shows in normal, nontransformed livers that fat induces glucose metabolism similar to an oncogenic transformation.

Simple Summary Glycolysis is one of the hallmarks of cancer. Therefore, the development of novel therapeutical strategies for colorectal cancer targeting glycolysis may improve treatment responses. PFKFB3 expression has been directly associated with enhanced glycolysis, not only in cancer cells but also within the tumor environment. The aim of this study was to evaluate PFKFB3 expression and its correlation with outcome in rectal and colon tumors and to assess the effects of the newly developed PFKFB3 inhibitor KAN0438757 on colorectal cancer cells and intestinal patient-derived organoids. Our results showed that KAN0438757 efficiently targets PFKFB3 expression and was able to affect cancer cell motility, invasion and survival. Additionally, a tumor specific cytotoxic-effect was observed in patient-derived organoids. In vivo, KAN0438757 showed to be well tolerated by mice without systemic toxicity. Our work re-enforces the concept that targeting of glycolysis may be a promising therapeutical approach for colorectal cancer. Abstract Background: Despite substantial progress made in the last decades in colorectal cancer (CRC) research, new treatment approaches are still needed to improve patients’ long-term survival. To date, the promising strategy to target tumor angiogenesis metabolically together with a sensitization of CRC to chemo- and/or radiotherapy by PFKFB3 (6-phosphofructo-2-kinase/fructose-2,6-biphosphatase-3) inhibition has never been tested. Therefore, initial evaluation and validation of newly developed compounds such as KAN0438757 and their effects on CRC cells are crucial steps preceding to in vivo preclinical studies, which in turn may consolidate new therapeutic targets. Materials and Methods: The efficiency of KAN0438757 to block PFKFB3 expression and translation in human CRC cells was evaluated by immunoblotting and real-time PCR. Functional in vitro assays assessed the effects of KAN0438757 on cell viability, proliferation, survival, adhesion, migration and invasion. Additionally, we evaluated the effects of KAN0438757 on matched patient-derived normal and tumor organoids and its systemic toxicity in vivo in C57BL6/N mice. Results: High PFKFB3 expression is correlated with a worse survival in CRC patients. KAN0438757 reduces PFKFB3 protein expression without affecting its transcriptional regulation. Additionally, a concentration-dependent anti-proliferative effect was observed. The migration and invasion capacity of cancer cells were significantly reduced, independent of the anti-proliferative effect. When treating colonic patient-derived organoids with KAN0438757 an impressive effect on tumor organoids growth was apparent, surprisingly sparing normal colonic organoids. No high-grade toxicity was observed in vivo. Conclusion: The PFKFB3 inhibitor KAN0438757 significantly reduced CRC cell migration, invasion and survival. Moreover, on patient-derived cancer organoids KAN0438757 showed significant effects on growth, without being overly toxic in normal colon organoids and healthy mice. Our findings strongly encourage further translational studies to evaluate KAN0438757 in CRC therapy.

Cancer metastasis requires the transient activation of cellular programs enabling dissemination and seeding in distant organs. Genetic, transcriptional and translational intra-tumor heterogeneity contributes to this dynamic process. Beyond this, metabolic intra-tumor heterogeneity has also been observed, yet its role for cancer progression remains largely elusive. Here, we discovered that intra-tumor heterogeneity in phosphoglycerate dehydrogenase (PHGDH) protein expression drives breast cancer cell dissemination and metastasis formation. Specifically, we observed intra-tumor heterogeneous PHGDH expression in primary breast tumors, with low PHGDH expression being indicative of metastasis in patients. In mice, Phgdh protein, but not mRNA, expression is low in circulating tumor cells and early metastatic lesions, leading to increased dissemination and metastasis formation. Mechanistically, low PHGDH protein expression induces an imbalance in glycolysis that can activate sialic acid synthesis. Consequently, cancer cells undergo a partial EMT and show increased p38 as well as SRC phosphorylation, which activate cellular programs of dissemination. In turn, inhibition of sialic acid synthesis through knock-out of cytidine monophosphate N-acetylneuraminic acid synthetase (CMAS) counteracts the increased cancer cell dissemination and metastasis induced by low PHGDH expression. In conclusion, we find that heterogeneity in PHGDH protein expression promotes cancer cell dissemination and metastasis formation.

In tumors, nutrient availability and metabolism are known to be important modulators of growth signaling. However, it remains elusive whether cancer cells that are growing out in the metastatic niche rely on the same nutrients and metabolic pathways to activate growth signaling as cancer cells within the primary tumor. We discovered that breast-cancer-derived lung metastases, but not the corresponding primary breast tumors, use the serine biosynthesis pathway to support mTORC1 growth signaling. Mechanistically, pyruvate uptake through Mct2 supported mTORC1 signaling by fueling serine biosynthesis-derived α-ketoglutarate production in breast-cancer-derived lung metastases. Consequently, expression of the serine biosynthesis enzyme PHGDH was required for sensitivity to the mTORC1 inhibitor rapamycin in breast-cancer-derived lung tumors, but not in primary breast tumors. In summary, we provide in vivo evidence that the metabolic and nutrient requirements to activate growth signaling differ between the lung metastatic niche and the primary breast cancer site. ispartof: Molecular Cell vol:81 issue:2 ispartof: location:United States status: Published online

Overcoming anticancer drug resistance is a major challenge in cancer therapy, requiring innovative strategies that consider the extensive tumor heterogeneity and adaptability. We provide recent evidence highlighting the key role of amino acid (AA) metabolic reprogramming in cancer cells and the supportive microenvironment in driving resistance to anticancer therapies. AAs sustain the acquisition of anticancer resistance by providing essential building blocks for biosynthetic pathways and for maintaining a balanced redox status, and modulating the epigenetic profile of both malignant and non-malignant cells. In addition, AAs support the reduced intrinsic susceptibility of cancer stem cells to antineoplastic therapies. These findings shed new light on the possibility of targeting nonresponding tumors by modulating AA availability through pharmacological or dietary interventions.

Cancer cells continuously rewire their metabolism to fulfill their need for rapid growth and survival while subject to changes in environmental cues. Thus, a vital component of a cancer cell lies in its metabolic adaptability. The constant demand for metabolic alterations requires flexibility, that is, the ability to utilize different metabolic substrates; as well as plasticity, that is, the ability to process metabolic substrates in different ways. In this review, we discuss how dynamic changes in cancer metabolism affect tumor progression and the consequential implications for cancer therapy. Significance: Recognizing cancer dynamic metabolic adaptability as an entity can lead to targeted therapy that is expected to decrease drug resistance.

Cancer cells frequently lack nutrients like glucose, due to insufficient vascular networks. Mitochondrial phosphoenolpyruvate carboxykinase, PCK2, has recently been found to mediate partial gluconeogenesis and hence anabolic metabolism in glucose starved cancer cells. Here we show that PCK2 acts as a regulator of mitochondrial respiration and maintains the redox balance in nutrient-deprived human lung cancer cells. PCK2 silencing increased the abundance and interconversion of tricarboxylic acid (TCA) cycle intermediates, augmented mitochondrial respiration and enhanced glutathione oxidation under glucose and serum starvation, in a PCK2 re-expression reversible manner. Moreover, enhancing the TCA cycle by PCK2 inhibition severely reduced colony formation of lung cancer cells under starvation. As a conclusion, PCK2 contributes to maintaining a reduced glutathione pool in starved cancer cells besides mediating the biosynthesis of gluconeogenic/glycolytic intermediates. The study sheds light on adaptive responses in cancer cells to nutrient deprivation and shows that PCK2 confers protection against respiration-induced oxidative stress., Free Radical Biology and Medicine, 176, ISSN:0891-5849, ISSN:1873-4596

Nutrients are indispensable resources that provide the macromolecular building blocks and energy requirements for sustaining cell growth and survival. Cancer cells require several key nutrients to fulfill their changing metabolic needs as they progress through stages of development. Moreover, both cell-intrinsic and microenvironment-influenced factors determine nutrient dependencies throughout cancer progression-for which a comprehensive characterization remains incomplete. In addition to the widely studied role of genetic alterations driving cancer metabolism, nutrient use in cancer tissue may be affected by several factors including the following: (i) diet, the primary source of bodily nutrients which influences circulating metabolite levels; (ii) tissue of origin, which can influence the tumor's reliance on specific nutrients to support cell metabolism and growth; (iii) local microenvironment, which dictates the accessibility of nutrients to tumor cells; (iv) tumor heterogeneity, which promotes metabolic plasticity and adaptation to nutrient demands; and (v) functional demand, which intensifies metabolic reprogramming to fuel the phenotypic changes required for invasion, growth, or survival. Here, we discuss the influence of these factors on nutrient metabolism and dependence during various steps of tumor development and progression. ispartof: EMBO Reports vol:21 issue:10 ispartof: location:England status: published

Metabolic rewiring is a hallmark of cancer that supports tumor growth, survival and chemotherapy resistance. While normal cells often rely on extracellular serine and glycine supply, a significant subset of cancers becomes addicted to intracellular serine/glycine synthesis, offering an attractive drug target. Previously developed inhibitors of serine/glycine synthesis enzymes did not reach clinical trials due to unfavorable pharmacokinetic profiles, implying that further efforts to identify clinically applicable drugs targeting this pathway are required. In this study, we aimed to develop therapies that can rapidly enter the clinical practice by focusing on drug repurposing, as their safety and cost-effectiveness have been optimized before. Using a yeast model system, we repurposed two compounds, sertraline and thimerosal, for their selective toxicity against serine/glycine synthesis addicted breast cancer and T-cell acute lymphoblastic leukemia cell lines. Isotope tracer metabolomics, computational docking studies and an enzymatic activity assay revealed that sertraline and thimerosal inhibit serine/glycine synthesis enzymes serine hydroxymethyltransferase and phosphoglycerate dehydrogenase, respectively. In addition, we demonstrated that sertraline’s anti-proliferative activity was further aggravated by mitochondrial inhibitors, such as the antimalarial artemether, by causing G1-S cell cycle arrest. Most notably, this combination also resulted in serine-selective antitumor activity in breast cancer mouse xenografts. Collectively, this study provides molecular insights into the repurposed mode-of-action of the antidepressant sertraline and allows to delineate a hitherto unidentified group of cancers being particularly sensitive to treatment with sertraline. Furthermore, we highlight the simultaneous inhibition of serine/glycine synthesis and mitochondrial metabolism as a novel treatment strategy for serine/glycine synthesis addicted cancers.

SummaryFrom age 65 onwards, the risk of cancer incidence and associated mortality is substantially higher1-3. Nonetheless, our understanding of the complex relationship between age and cancer is still in its infancy4. For decades, the link has largely been attributed to increased exposure time to mutagens in older individuals. However, this view does not account for the well-established role of diet, exercise and small molecules that target the pace of metabolic aging5-8. Here, we show that metabolic alterations that occur with age can render a systemic environment favorable to progression and aggressiveness of tumors. Specifically, we show that methylmalonic acid (MMA), a by-product of propionate metabolism, is significantly up-regulated in the serum of older people, and functions as a mediator of tumor progression. We traced this to the induction of SOX4 and a consequent transcriptional reprogramming that can endow cancer cells with aggressive properties. Thus, accumulation of MMA represents a novel link between aging and cancer progression, implicating MMA as a novel therapeutic target for advanced carcinomas.

Despite the clinical success of Androgen Receptor (AR)-targeted therapies, reactivation of AR signalling remains the main driver of castration-resistant prostate cancer (CRPC) progression. In this study, we perform a comprehensive unbiased characterisation of LNCaP cells chronically exposed to multiple AR inhibitors (ARI). Combined proteomics and metabolomics analyses implicate an acquired metabolic phenotype common in ARI-resistant cells and associated with perturbed glucose and lipid metabolism. To exploit this phenotype, we delineate a subset of proteins consistently associated with ARI resistance and highlight mitochondrial 2,4-dienoyl-CoA reductase (DECR1), an auxiliary enzyme of beta-oxidation, as a clinically relevant biomarker for CRPC. Mechanistically, DECR1 participates in redox homeostasis by controlling the balance between saturated and unsaturated phospholipids. DECR1 knockout induces ER stress and sensitises CRPC cells to ferroptosis. In vivo, DECR1 deletion impairs lipid metabolism and reduces CRPC tumour growth, emphasizing the importance of DECR1 in the development of treatment resistance., Androgen receptor (AR) signalling regulates cellular metabolism in prostate cancer. Here, the authors perform a proteomics and metabolomics characterisation of prostate cancer cells adapted to long-term resistance to AR inhibition and show rewiring of glucose and lipid metabolism, and further identify a signature associated with resistance to AR inhibition.

The formation of new blood vessels, or angiogenesis, is a complex process that plays important roles in growth and development, tissue and organ regeneration, as well as numerous pathological conditions. Angiogenesis undergoes multiple discrete steps that can be individually evaluated and quantified by a large number of bioassays. These independent assessments hold advantages but also have limitations. This article describes in vivo, ex vivo, and in vitro bioassays that are available for the evaluation of angiogenesis and highlights critical aspects that are relevant for their execution and proper interpretation. As such, this collaborative work is the first edition of consensus guidelines on angiogenesis bioassays to serve for current and future reference. Fil: Nowak Sliwinska, Patrycja. Université of Lausanne; Suiza. Univeristé of Geneve; Suiza Fil: Alitalo, Kari. Katholikie Universiteit Leuven; Bélgica Fil: Allen, Elizabeth. Katholikie Universiteit Leuven; Bélgica Fil: Anisimov, Andrey. Katholikie Universiteit Leuven; Bélgica Fil: Aplin, Alfred C.. University of Washington; Estados Unidos Fil: Auerbach, Robert. University of Wisconsin; Estados Unidos Fil: Augustin, Hellmut G.. Heidelberg University; Alemania. German Cancer Consortium; Alemania Fil: Bates, David O.. University of Nottingham; Reino Unido Fil: Beijnum, Judy R. van. Cancer Center Amsterdam; Países Bajos Fil: Bender, R. Hugh F.. University of California; Estados Unidos Fil: Bergers, Gabriele. Katholikie Universiteit Leuven; Bélgica Fil: Bikfalvi, Andreas. Universite de Bordeaux; Francia Fil: Bischoff, Joyce. Harvard Medical School; Estados Unidos Fil: Böck, Barbara C.. Heidelberg University; Alemania. German Cancer Consortium; Alemania Fil: Brooks, Peter C.. Maine Medical Center Research Institute; Estados Unidos Fil: Bussolino, Federico. Università di Torino; Italia. Candiolo Cancer Institute; Italia Fil: Cakir, Bertan. Harvard Medical School; Estados Unidos Fil: Carmeliet, Peter. Katholikie Universiteit Leuven; Bélgica Fil: Castranova, Daniel. Harvard Medical School; Estados Unidos Fil: Cimpean, Anca M.. Victor Babes University of Medicine and Pharmacy; Rumania Fil: Cleaver, Ondine. University Of Texas At Brownsville; Estados Unidos Fil: Coukos, George. Universida de Lausanne; Suiza Fil: Davis, George E.. University of Missouri; Estados Unidos Fil: De Palma, Michele. Swiss Federal Institute of Technology; Suiza Fil: Dimberg, Anna. Uppsala University; Suiza Fil: Dings, Ruud P. M.. University of Arkansas for Medical Sciences; Estados Unidos Fil: Djonov, Valentin. University of Bern; Suiza Fil: Dudley, Andrew C.. University of Virginia; Estados Unidos Fil: Dufton, Neil P.. Imperial College London; Reino Unido Fil: Fendt, Sarah-Maria. VIB Center for Cancer Biology; Bélgica Fil: Ferrara, Napoleone. University of California at San Diego; Estados Unidos Fil: Fruttiger, Marcus. University College London; Estados Unidos Fil: Fukumura, Dai. Harvard Medical School; Estados Unidos Fil: Ghesquière, Bart. Harvard Medical School; Estados Unidos Fil: Gong, Yan. Harvard Medical School; Estados Unidos Fil: Griffin, Robert J.. VIB Center for Cancer Biology; Bélgica Fil: Harris, Adrian L.. University of Oxford; Reino Unido Fil: Hughes, Christopher C. W.. University of California at Irvine; Estados Unidos Fil: Hultgren, Nan W.. University of California at Irvine; Estados Unidos Fil: Iruela-Arispe, M. Luisa. University of California at Los Angeles; Estados Unidos Fil: Irving, Melita. Universida de Lausanne; Suiza Fil: Maidana, Agostina Jainen. Harvard Medical School; Estados Unidos Fil: Kalluri, Raghu. Texas A&M University; Estados Unidos Fil: Kalucka, Joanna. Katholikie Universiteit Leuven; Bélgica Fil: Kerbel, Robert S.. University of Toronto; Canadá Fil: Kitajewski, Jan. University of Illinois; Estados Unidos Fil: Klaassen, Ingeborg. University of Amsterdam; Países Bajos Fil: Kleinmann, Hynda K.. The George Washington University; Estados Unidos Fil: Koolwijk, Pieter. Fondation Asile des Aveugles; Suiza. Universida de Lausanne; Suiza Fil: Kuczynski, Elisabeth. University of Toronto; Canadá Fil: Kwak, Brenda R.. University of Geneva; Suiza Fil: Koen, Marien. HistoGeneX; Bélgica Fil: Melero Martin, Juan M.. University of Liège; Bélgica Fil: Munn, Lance L.. Harvard Medical School; Estados Unidos Fil: Nicosia, Roberto F.. VA Puget Sound Health Care System; Estados Unidos Fil: Noel, Agnes. University of Liège; Bélgica Fil: Nurro, Jussi. University of Eastern Finland; Finlandia Fil: Olsson, Anna-Karin. Uppsala University; Suiza Fil: Petrova, Tatiana V.. Ludwig Institute for Cancer Research Lausanne; Suiza Fil: Pietras, Kristian. Division of Translational Cancer Research; Suecia Fil: Pili, Roberto. Indiana University Simon Cancer Center; Estados Unidos Fil: Pollard, Jeffrey W.. University of Edinburgh; Reino Unido Fil: Post, Mark J.. Maastricht University; Países Bajos Fil: Quax, Paul H. A.. Einthoven Laboratory for Experimental Vascular Medicine; Países Bajos Fil: Rabinovich, Gabriel Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina Fil: Raica, Marius. Victor Babes University of Medicine and Pharmacy; Rumania Fil: Randi, Anna M.. Imperial College London; Reino Unido Fil: Ribatti, Domenico. Università degli Studi di Bari; Italia Fil: Ruegg, Curzio. University of Fribourg; Suiza Fil: Schlingemann, Reinier O.. University of Amsterdam; Países Bajos Fil: Schulte Merker, Stefan. Institute of Cardiovascular Organogenesis and Regeneration; Alemania Fil: Smith, Lois E. H.. Harvard Medical School; Estados Unidos Fil: Song, Jonathan W.. Ohio State University; Estados Unidos Fil: Stacker, Steven A.. University of Melbourne; Australia Fil: Stalin, Jimmy. Institute of Cardiovascular Organogenesis and Regeneration; Alemania Fil: Stratman, Amber N.. National Institutes of Health; Estados Unidos Fil: Van de Velde, Maureen. University of Liège; Bélgica Fil: van Hinsbergh, Victor W. M.. Universida de Lausanne; Suiza Fil: Vermeulen, Peter B.. HistoGeneX; Bélgica. University of Antwerp; Bélgica Fil: Waltenberger, Johannes. University of Münster; Alemania Fil: Weinstein, Brant M.. National Institutes of Health; Estados Unidos Fil: Xin, Hong. University of California at San Diego; Estados Unidos Fil: Yetkin Arik, Bahar. University of Amsterdam; Países Bajos Fil: Yla Herttuala, Seppo. University of Eastern Finland; Finlandia Fil: Yoder, Mervin C.. Indiana University; Estados Unidos Fil: Griffioen, Arjan W.. VU University Medical Center; Países Bajos

The R98S mutation in ribosomal protein L10 (RPL10 R98S) affects 8% of pediatric T-cell acute lymphoblastic leukemia (T-ALL) cases, and was previously described to impair cellular proliferation. The current study reveals that RPL10 R98S cells accumulate reactive oxygen species which promotes mitochondrial dysfunction and reduced ATP levels, causing the proliferation defect. RPL10 R98S mutant leukemia cells can survive high oxidative stress levels via a specific increase of IRES-mediated translation of the anti-apoptotic factor B-cell lymphoma 2 (BCL-2), mediating BCL-2 protein overexpression. RPL10 R98S selective sensitivity to the clinically available Bcl-2 inhibitor Venetoclax (ABT-199) was supported by suppression of splenomegaly and the absence of human leukemia cells in the blood of T-ALL xenografted mice. These results shed new light on the oncogenic function of ribosomal mutations in cancer, provide a novel mechanism for BCL-2 upregulation in leukemia, and highlight BCL-2 inhibition as a novel therapeutic opportunity in RPL10 R98S defective T-ALL. ispartof: LEUKEMIA vol:33 issue:2 pages:319-332 ispartof: location:England status: published

Whereas significant anti-tumor responses are observed in most BRAFV600E-mutant melanoma patients exposed to MAPK-targeting agents, resistance almost invariably develops. Here, we show that in therapy-responsive cells BRAF inhibition induces downregulation of the processing of Sterol Regulator Element Binding (SREBP-1) and thereby lipogenesis. Irrespective of the escape mechanism, therapy-resistant cells invariably restore this process to promote lipid saturation and protect melanoma from ROS-induced damage and lipid peroxidation. Importantly, pharmacological SREBP-1 inhibition sensitizes BRAFV600E-mutant therapy-resistant melanoma to BRAFV600E inhibitors both in vitro and in a pre-clinical PDX in vivo model. Together, these data indicate that targeting SREBP-1-induced lipogenesis may offer a new avenue to overcome acquisition of resistance to BRAF-targeted therapy. This work also provides evidence that targeting vulnerabilities downstream of oncogenic signaling offers new possibilities in overcoming resistance to targeted therapies., Melanoma patients harbouring BRAFV600E mutation generally develop resistance to targeted therapy. In this study, the authors demonstrate that SREBP-1-mediated induction of lipid biosynthesis contributes to therapy resistance in BRAF mutant melanoma.

Introduction Multiple myeloma (MM) remains an incurable cancer despite advances in therapy. Therefore, the search for new targets is still essential to uncover potential treatment strategies. Metabolic changes, induced by the hypoxic bone marrow, contribute to both cancer cell survival and drug resistance. In this study, we aimed to identify which metabolic changes and downstream pathways are involved in myeloma cell growth and persistence. Methods Correlation of pyrroline-5-carboxylate reductase 1 and 2 (PYCR1 and PYCR2) with overall survival was investigated in the gene-expression data of MM patients (MMRF CoMMpass trial). To perform a tracer study, RPMI-8226 cells were supplemented with 13C-glutamine for 48h in both normoxia and hypoxia ( Results Pyrroline-5-carboxylate reductase 1 and 2 (PYCR1 and PYCR2) are 2 mitochondrial enzymes that facilitate the last step in the enzymatic conversion of glutamine to proline. High expression of both enzymes correlated with a lower overall survival in the CoMMpass trial. Moreover, MM cells from relapse/refractory patients expressed significant higher levels of PYCR1. We performed a tracer study with RPMI-8226 cells, revealing an increased conversion of 13C-glutamine to proline in hypoxia compared to normoxia. We confirmed these results by increased proline production after 48h of hypoxic culture. SiRNA-mediated knockdown of PYCR1 or both PYCR1/2 combined with bortezomib increased apoptotic cell death in OPM-2 and RPMI-8226, which we confirmed by detecting upregulation of cleaved PARP and cleaved CASPASE 3 levels. In contrast, PYCR2 knockdown combined with bortezomib did not significantly alter apoptosis. Further investigation revealed that PYCR1 knockdown reduced proliferation, and led to a decrease in p-AKT, p-p42/44 MAPK and c-MYC levels. Mechanistically, we found that PYCR1 silencing affected protein synthesis, as shown by a downregulation of p-PRAS40, p-MTOR, p-p70, p-S6, p-4EBP1 and p-EIF4e levels. Next, we evaluated whether the clinically relevant anti-hypertensive agent and PYCR1 inhibitor, pargyline, was capable of inducing myeloma cell death. In vitro, pargyline reduced proline production, MM viability and increased apoptotic cell death. Pargyline was also capable of reducing viability in CD138+ cells of primary patient samples . Finally, in vivo combination of pargyline with bortezomib significantly reduced tumor burden in the 5TGM1 model. On protein level, we also observed a significant decrease in p-4EBP1 and p-EIF4e in the freshly isolated 5TGM1 cells for the combination therapy. Conclusion Hypoxia increased glutamine-to-proline conversion in myeloma cells by stimulating PYCR activity. Knockdown of PYCR1 and PYCR1/2 increased bortezomib efficacy and inhibited proliferation. Mechanistically, PYCR1 interference reduced PRAS40-mediated protein synthesis. Pargyline, a PYCR1 inhibitor, also reduced MM viability and increased apoptosis. In vivo, pargyline combined with bortezomib significantly reduced tumor burden in the 5TGM1 model compared to both single agents. In conclusion, this study identifies PYCR1 as a novel target in MM therapy. Disclosures De Veirman: Active Biotech AB: Research Funding. OffLabel Disclosure: Pargyline is a antihypertensive agent and irreversible MAO B inhibitor that also inhibits PYCR1. Pargyline is not approved by the FDA as a PYCR1 inhibitor.

Mutations in succinate dehydrogenase (SDH) are associated with tumor development and neurodegenerative diseases. Only in tumors, loss of SDH activity is accompanied with the loss of complex I activity. Yet, it remains unknown whether the metabolic phenotype of SDH mutant tumors is driven by loss of complex I function, and whether this contributes to the peculiarity of tumor development versus neurodegeneration. We addressed this question by decoupling loss of SDH and complex I activity in cancer cells and neurons. We found that sole loss of SDH activity was not sufficient to recapitulate the metabolic phenotype of SDH mutant tumors, because it failed to decrease mitochondrial respiration and to activate reductive glutamine metabolism. These metabolic phenotypes were only induced upon the additional loss of complex I activity. Thus, we show that complex I function defines the metabolic differences between SDH mutation associated tumors and neurodegenerative diseases, which could open novel therapeutic options against both diseases. ispartof: Metabolic Engineering vol:43 issue:Pt B pages:187-197 ispartof: location:Belgium status: published

Glutamine metabolism provides synergistic support for macrophage activation and elicitation of desirable immune responses; however, the underlying mechanisms regulated by glutamine metabolism to orchestrate macrophage activation remain unclear. Here we show that the production of α-ketoglutarate (αKG) via glutaminolysis is important for alternative (M2) activation of macrophages, including engagement of fatty acid oxidation (FAO) and Jmjd3-dependent epigenetic reprogramming of M2 genes. This M2-promoting mechanism is further modulated by a high αKG/succinate ratio, whereas a low ratio strengthens the proinflammatory phenotype in classically activated (M1) macrophages. As such, αKG contributes to endotoxin tolerance after M1 activation. This study reveals new mechanistic regulations by which glutamine metabolism tailors the immune responses of macrophages through metabolic and epigenetic reprogramming. ispartof: Nature Immunology vol:18 issue:9 pages:985-994 ispartof: location:United States status: published

Metastases are the leading cause of mortality in patients with cancer. Metastasis formation requires cancer cells to adapt their cellular phenotype. However, how metabolism supports this adaptation of cancer cells is poorly defined. We use 2D versus 3D cultivation to induce a shift in the cellular phenotype of breast cancer cells. We discover that proline catabolism via proline dehydrogenase (Prodh) supports growth of breast cancer cells in 3D culture. Subsequently, we link proline catabolism to in vivo metastasis formation. In particular, we find that PRODH expression and proline catabolism is increased in metastases compared to primary breast cancers of patients and mice. Moreover, inhibiting Prodh is sufficient to impair formation of lung metastases in the orthotopic 4T1 and EMT6.5 mouse models, without adverse effects on healthy tissue and organ function. In conclusion, we discover that Prodh is a potential drug target for inhibiting metastasis formation., Metastasizing cancer cells rewire their metabolism to support their malignant phenotypes. Here, the authors show that the acquisition of a metastatic phenotype in breast cancer cell lines results in increased proline catabolism and that inhibition of this pathway decreases lung metastasis formation in two mouse models.

Summary The TIGAR protein has antioxidant activity that supports intestinal tissue repair and adenoma development. Using a pancreatic ductal adenocarcinoma (PDAC) model, we show that reactive oxygen species (ROS) regulation by TIGAR supports premalignant tumor initiation while restricting metastasis. Increased ROS in PDAC cells drives a phenotypic switch that increases migration, invasion, and metastatic capacity. This switch is dependent on increased activation of MAPK signaling and can be reverted by antioxidant treatment. In mouse and human, TIGAR expression is modulated during PDAC development, with higher TIGAR levels in premalignant lesions and lower TIGAR levels in metastasizing tumors. Our study indicates that temporal, dynamic control of ROS underpins full malignant progression and helps to rationalize conflicting reports of pro- and anti-tumor effects of antioxidant treatment., Graphical Abstract, Highlights • ROS regulation by TIGAR supports premalignant pancreas tumor development • Increased ROS following TIGAR or Nrf2 loss enhance metastasis • ROS reduce DUSP6 expression to activate ERK and increase invasion and migration • TIGAR and ROS levels are dynamically regulated throughout tumor progression, Cheung et al. show that TIGAR expression is dynamically regulated during the development of pancreatic ductal adenocarcinoma, resulting in lower levels of ROS to promote tumor initiation in the premalignant condition and higher levels of ROS that enable metastatic progression.

Summary Cancer cells display an increased plasticity in their lipid metabolism, which includes the conversion of palmitate to sapienate via the enzyme fatty acid desaturase 2 (FADS2). We find that FADS2 expression correlates with mammalian target of rapamycin (mTOR) signaling and sterol regulatory element-binding protein 1 (SREBP-1) activity across multiple cancer types and is prognostic in some cancer types. Accordingly, activating mTOR signaling by deleting tuberous sclerosis complex 2 (Tsc2) or overexpression of SREBP-1/2 is sufficient to increase FADS2 mRNA expression and sapienate metabolism in mouse embryonic fibroblasts (MEFs) and U87 glioblastoma cells, respectively. Conversely, inhibiting mTOR signaling decreases FADS2 expression and sapienate biosynthesis in MEFs with Tsc2 deletion, HUH7 hepatocellular carcinoma cells, and orthotopic HUH7 liver xenografts. In conclusion, we show that mTOR signaling and SREBP activity are sufficient to activate sapienate metabolism by increasing FADS2 expression. Consequently, targeting mTOR signaling can reduce sapienate metabolism in vivo., Graphical Abstract, Highlights • FADS2 expression is prognostic in some cancers • FADS2 is a target of SREBP-1 and SREBP-2 • SREBP activity and mTOR signaling regulate FADS2-mediated sapienate metabolism • Torin1 treatment reduces FADS2 expression and sapienate metabolism in xenografts, Triki et al. report that FADS2 expression is prognostic in some cancers and that FADS2-mediated sapienate metabolism is regulated by mTOR signaling. Mechanistically, FADS2 is a target of SREBP-1/2. Inhibition of mTOR or SREBP reduces FADS2 expression and sapienate metabolism in cancer cells and liver xenografts.

Summary Endothelial cell (EC)-derived signals contribute to organ regeneration, but angiocrine metabolic communication is not described. We found that EC-specific loss of the glycolytic regulator pfkfb3 reduced ischemic hindlimb revascularization and impaired muscle regeneration. This was caused by the reduced ability of macrophages to adopt a proangiogenic and proregenerative M2-like phenotype. Mechanistically, loss of pfkfb3 reduced lactate secretion by ECs and lowered lactate levels in the ischemic muscle. Addition of lactate to pfkfb3-deficient ECs restored M2-like polarization in an MCT1-dependent fashion. Lactate shuttling by ECs enabled macrophages to promote proliferation and fusion of muscle progenitors. Moreover, VEGF production by lactate-polarized macrophages was increased, resulting in a positive feedback loop that further stimulated angiogenesis. Finally, increasing lactate levels during ischemia rescued macrophage polarization and improved muscle reperfusion and regeneration, whereas macrophage-specific mct1 deletion prevented M2-like polarization. In summary, ECs exploit glycolysis for angiocrine lactate shuttling to steer muscle regeneration from ischemia., Graphical Abstract, Highlights • Endothelial loss of pfkfb3 impairs ischemic muscle revascularization and regeneration • EC-derived lactate instructs MCT1-dependent macrophage functional polarization • Lactate-polarized macrophages promote muscle revascularization and regeneration • Restoring lactate levels improves macrophage polarization and recovery from ischemia, Endothelial cells (ECs) critically control muscle recovery from ischemia by secreting lactate. Angiocrine lactate is taken up and oxidized by macrophages in an MCT1-dependent fashion. Lactate-mediated macrophage polarization promotes revascularization and muscle regeneration. Consequently, EC-specific loss of pfkfb3 lowers muscle lactate levels and impairs muscle recovery from ischemia.