Glycine decarboxylase is a metabolic oncogene critical for tumor initiating cells and tumorigenesis in lung cancer
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ABSTRACT: New approaches to cancer therapies could benefit from a better understanding of the molecular determinants critical to tumor initiating cells (TICs). Here we show that the metabolic enzyme glycine decarboxylase (GLDC) is critical for TICs in non-small cell lung cancer (NSCLC). From a broad range of primary NSCLC tumors, we isolated CD166+ lung TICs that consistently initiated tumorigenesis in NOD/SCID Il2rγ-/- mice. Lung TICs express high levels of the oncogenic stem cell factor LIN28B and the metabolic enzyme GLDC. Over-expression of GLDC and other glycine/serine metabolism enzymes, but not catalytically inactive GLDC, promotes cellular transformation and tumorigenesis. Metabolomic analysis found that GLDC induces dramatic changes in glycolysis and glycine/serine metabolism, leading to changes in pyrimidine metabolism to regulate cancer cell proliferation. Clinically, GLDC over-expression, observed in multiple cancer types, predicts poorer survival in lung cancer patients. Our findings establish a novel link between glycine metabolism and tumorigenesis, and provide novel targets for advancing anti-cancer therapy.
Project description:New approaches to cancer therapies could benefit from a better understanding of the molecular determinants critical to tumor initiating cells (TICs). Here we show that the metabolic enzyme glycine decarboxylase (GLDC) is critical for TICs in non-small cell lung cancer (NSCLC). From a broad range of primary NSCLC tumors, we isolated CD166+ lung TICs that consistently initiated tumorigenesis in NOD/SCID Il2rγ-/- mice. Lung TICs express high levels of the oncogenic stem cell factor LIN28B and the metabolic enzyme GLDC. Over-expression of GLDC and other glycine/serine metabolism enzymes, but not catalytically inactive GLDC, promotes cellular transformation and tumorigenesis. Metabolomic analysis found that GLDC induces dramatic changes in glycolysis and glycine/serine metabolism, leading to changes in pyrimidine metabolism to regulate cancer cell proliferation. Clinically, GLDC over-expression, observed in multiple cancer types, predicts poorer survival in lung cancer patients. Our findings establish a novel link between glycine metabolism and tumorigenesis, and provide novel targets for advancing anti-cancer therapy. Total RNA obtained from tumor sphere compared to CD166+ and CD166- selected cells of xenograft, primary tumor and normal donors
Project description:In this study, we provide evidence that spheroids cells isolated from established human NSCLC cell lines are highly enriched in NSCLC-TICs that aberrant Akt-IL6-Stat3 signalling axis is necessary for self-renewal of lung TICs in vitro and for tumor formation in vivo.
Project description:Increased activation of the serine-glycine biosynthetic pathway is an integral part of cancer metabolism that drives macromolecule synthesis needed for cell proliferation. Whether this pathway is under epigenetic control is unknown. Here we show that the histone H3 lysine 9 (H3K9) methyltransferase G9A is required for maintaining the pathway enzyme genes in an active state marked by H3K9 monomethylation and for the transcriptional activation of this pathway in response to serine deprivation. G9A inactivation depletes serine and its downstream metabolites, triggering cell death with autophagy in cancer cell lines of different tissue origins. Higher G9A expression, which is observed in various cancers and is associated with greater mortality in cancer patients, increases serine production and enhances the proliferation and tumorigenicity of cancer cells. These findings identify a G9A-dependent epigenetic program in the control of cancer metabolism, providing a rationale for G9A inhibition as a therapeutic strategy for cancer. Affymetrix microarray assays were performed according to the manufacturer's directions on total RNA isolated from three independent samples of BE(2)-C cells treated either with 0.05% DMSO or with 5 M-BM-5M BIX01294 (B9311, Sigma-Aldrich) for 24 hours.
Project description:Increased activation of the serine-glycine biosynthetic pathway is an integral part of cancer metabolism that drives macromolecule synthesis needed for cell proliferation. Whether this pathway is under epigenetic control is unknown. Here we show that the histone H3 lysine 9 (H3K9) methyltransferase G9A is required for maintaining the pathway enzyme genes in an active state marked by H3K9 monomethylation and for the transcriptional activation of this pathway in response to serine deprivation. G9A inactivation depletes serine and its downstream metabolites, triggering cell death with autophagy in cancer cell lines of different tissue origins. Higher G9A expression, which is observed in various cancers and is associated with greater mortality in cancer patients, increases serine production and enhances the proliferation and tumorigenicity of cancer cells. These findings identify a G9A-dependent epigenetic program in the control of cancer metabolism, providing a rationale for G9A inhibition as a therapeutic strategy for cancer.
Project description:Following therapy, tumour-initiating cells (TICs) survive and give rise to second-line tumours. Gene set enrichment analysis of microarray data and microRNA analysis confirmed the validity of spheroid cultures as models of TICs for breast and prostate cancer and mesothelioma cell lines. Pathway analysis revealed increased Trp metabolism in all types of TICs with indoleamine 2,3-dioxygenase (IDO) as the rate-limiting enzyme. TICs also expressed higher levels of the Trp uptake system consisting of CD98 and LAT1 with functional consequences. Mitocans, represented by vitamin E (VE) analogues, suppressed IDO1 in TICs with functional mitochondrial complex II, a target for the agents. IDO1 expression was regulated via a mechanism involving both transcriptional and post-transcriptional mechanisms. IDO1 increase and its suppression by VE analogues were replicated in TICs from primary human glioblastomas. Our work points to Trp metabolism as a novel mechanism of TICs to bypass the immune surveillance and to VE analogues as agents that remove this ‘mimicry’. Total RNA obtained from from breast cancer (MCF7), mesothelioma (IstMes2) and prostate cancer (LNCaP) adherent cell lines was compared to their corresponding sphere cultures
Project description:Non-small cell lung cancer (NSCLC), the most frequent subtype of lung cancer, remains a highly lethal malignancy and one of the leading causes of cancer deaths worldwide. Mutant KRAS is the prevailing oncogenic driver of lung adenocarcinoma, the most common histological form of NSCLC. In this study, we examined the role of PKCe, an oncogenic kinase highly expressed in NSCLC and other cancers, in KRAS-driven tumorigenesis. Notably, database analysis revealed an association between PKCe expression and poor outcome in lung adenocarcinoma patients specifically having KRAS mutation. By generating a PKCe-deficient, conditionally activatable allele of oncogenic Kras (LSL-Kras G12D ;PKCe -/- mice) we were able to demonstrate the requirement of PKCe for Kras-driven lung tumorigenesis in vivo, which is consistent with the impaired transformed growth observed in PKCe-deficient KRAS-dependent NSCLC cells. Moreover, PKCe-knockout mice were found to be less susceptible to lung tumorigenesis induced by benzo[a]pyrene, a carcinogen that induces mutations in Kras. Mechanistic analysis using RNA-Seq revealed little overlapping for PKCe and KRAS in the control of genes/biological pathways relevant in NSCLC, suggesting that a permissive role of PKCe in KRAS-driven lung tumorigenesis may involve non-redundant mechanisms. Our results thus highlight the relevance and potential of targeting PKCe for lung cancer therapeutics.
Project description:Somatic ribosomal protein defects have recently been described in cancer, yet their impact on cellular transcription and translation remain poorly understood. Here we integrated mRNA sequencing, ribosome footprinting, polysomal RNA seq and quantitative mass spectrometry datasets obtained from an isogenic mouse lymphoid cell model in order to study the T-cell acute lymphoblastic leukemia (T-ALL) associated R98S mutation in ribosomal protein L10 (RPL10 R98S). RPL10 R98S induced changes in protein levels were to a much larger extent caused by transcriptional then translational changes and RPL10 R98S cells showed a gene signature corresponding to deregulation of hematopoietic transcription factors. Phosphoserine phosphatase (PSPH), a key enzyme in serine biosynthesis, displayed elevated transcription and translation and was one of the proteins showing the strongest upregulation in RPL10 R98S cells. Increased Psph protein levels were confirmed in RPL10 R98S engineered JURKAT cells and in hematopoietic cell cultures derived from Rpl10 R98S knock-in mice. Moreover, elevated serine and glycine biosynthesis in RPL10 R98S cells was supported by metabolic flux analyses. Analysis of PSPH expression levels in T-ALL patient samples revealed that PSPH upregulation is a generalized phenomenon in this disease, associated with elevated circulating serine and glycine levels. Addition of serine and glycine enhanced survival of stromal and myeloid cells, suggesting supportive effects on the hematopoietic niche. Finally, reduction of PSPH expression levels in T-ALL cell lines suppressed their in vitro proliferation and their capacity to expand in T-ALL xenograft models. In conclusion, transcriptome, translatome and proteome analysis of the RPL10 R98S mutation identified RPL10 R98S driven induction of cellular serine biosynthesis. Whereas serine metabolism has been implicated in cancer via PHGDH amplification, this is the first report supporting dependence of ALL cells on the serine biosynthesis enzyme PSPH.
Project description:Somatic ribosomal protein defects have recently been described in cancer, yet their impact on cellular transcription and translation remain poorly understood. Here we integrated mRNA sequencing, ribosome footprinting, polysomal RNA seq and quantitative mass spectrometry datasets obtained from an isogenic mouse lymphoid cell model in order to study the T-cell acute lymphoblastic leukemia (T-ALL) associated R98S mutation in ribosomal protein L10 (RPL10 R98S). RPL10 R98S induced changes in protein levels were to a much larger extent caused by transcriptional then translational changes and RPL10 R98S cells showed a gene signature corresponding to deregulation of hematopoietic transcription factors. Phosphoserine phosphatase (PSPH), a key enzyme in serine biosynthesis, displayed elevated transcription and translation and was one of the proteins showing the strongest upregulation in RPL10 R98S cells. Increased Psph protein levels were confirmed in RPL10 R98S engineered JURKAT cells and in hematopoietic cell cultures derived from Rpl10 R98S knock-in mice. Moreover, elevated serine and glycine biosynthesis in RPL10 R98S cells was supported by metabolic flux analyses. Analysis of PSPH expression levels in T-ALL patient samples revealed that PSPH upregulation is a generalized phenomenon in this disease, associated with elevated circulating serine and glycine levels. Addition of serine and glycine enhanced survival of stromal and myeloid cells, suggesting supportive effects on the hematopoietic niche. Finally, reduction of PSPH expression levels in T-ALL cell lines suppressed their in vitro proliferation and their capacity to expand in T-ALL xenograft models. In conclusion, transcriptome, translatome and proteome analysis of the RPL10 R98S mutation identified RPL10 R98S driven induction of cellular serine biosynthesis. Whereas serine metabolism has been implicated in cancer via PHGDH amplification, this is the first report supporting dependence of ALL cells on the serine biosynthesis enzyme PSPH.
Project description:Somatic ribosomal protein defects have recently been described in cancer, yet their impact on cellular transcription and translation remain poorly understood. Here we integrated mRNA sequencing, ribosome footprinting, polysomal RNA seq and quantitative mass spectrometry datasets obtained from an isogenic mouse lymphoid cell model in order to study the T-cell acute lymphoblastic leukemia (T-ALL) associated R98S mutation in ribosomal protein L10 (RPL10 R98S). RPL10 R98S induced changes in protein levels were to a much larger extent caused by transcriptional then translational changes and RPL10 R98S cells showed a gene signature corresponding to deregulation of hematopoietic transcription factors. Phosphoserine phosphatase (PSPH), a key enzyme in serine biosynthesis, displayed elevated transcription and translation and was one of the proteins showing the strongest upregulation in RPL10 R98S cells. Increased Psph protein levels were confirmed in RPL10 R98S engineered JURKAT cells and in hematopoietic cell cultures derived from Rpl10 R98S knock-in mice. Moreover, elevated serine and glycine biosynthesis in RPL10 R98S cells was supported by metabolic flux analyses. Analysis of PSPH expression levels in T-ALL patient samples revealed that PSPH upregulation is a generalized phenomenon in this disease, associated with elevated circulating serine and glycine levels. Addition of serine and glycine enhanced survival of stromal and myeloid cells, suggesting supportive effects on the hematopoietic niche. Finally, reduction of PSPH expression levels in T-ALL cell lines suppressed their in vitro proliferation and their capacity to expand in T-ALL xenograft models. In conclusion, transcriptome, translatome and proteome analysis of the RPL10 R98S mutation identified RPL10 R98S driven induction of cellular serine biosynthesis. Whereas serine metabolism has been implicated in cancer via PHGDH amplification, this is the first report supporting dependence of ALL cells on the serine biosynthesis enzyme PSPH.
Project description:The biological significance of a small supernumerary marker chromosome generating a 9p24.1 duplication/triplication including a triplication of the GLDC gene encoding glycine decarboxylase in two patients with psychosis is unclear. Performing functional genomic fine-mapping using a series of copy number variant mouse models, we identify that additional copies of Gldc reduce extracellular glycine levels as determined by optical FRET in dentate gyrus (DG) but not in CA1, suppressed long-term potentiation (LTP) in mPP-DG synapses but not in CA3-CA1 synapses, reduced the activity of biochemical pathways implicated in schizophrenia and mitochondrial bioenergetics, and displayed prepulse inhibition, startle habituation, latent inhibition, working memory, sociability and social preference deficits. Our results thus provide a link between a genomic copy number variation, biochemical, cellular and behavioral phenotypes, demonstrating that GLDC negatively regulates excitatory neurotransmission, supporting the view that extra copies of GLDC in the genome may contribute significantly to the development of neuropsychiatric disorders.