LKB1 loss links the serine metabolic network to DNA methylation and tumourigenesis
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE86145 | GEO | 2016/10/24
SECONDARY ACCESSION(S): PRJNA340375
REPOSITORIES: GEO
Similar Datasets
Project description:Intermediary metabolism generates substrates for covalent modification of chromatin, enabling potential coupling of metabolic states and epigenetic control. Here, we identify such a network as a major component of oncogenic transformation downstream of the LKB1 tumour suppressor. LKB1 encodes a serine-threonine kinase that integrates nutrient availability, metabolism and growth, however the mechanisms for LKB1-dependent tumour suppression remain elusive. By developing genetically engineered mouse and primary epithelial cell models and employing transcriptional, proteomics, and metabolic analyses, we find that oncogenic cooperation between LKB1 loss and KRAS activation, alterations commonly coinciding in human cancer, is fueled by pronounced mTOR-dependent induction of the serine-glycine-one carbon network coupled to S-adenosylmethionine generation. In concert, DNA methyltransferases (DNMT1, DNMT3A) are upregulated, leading to elevation in genomic 5-methylcytosine levels, with particular enrichment at retrotransposon elements, associated with silencing of retrotransposon transcription. Correspondingly, LKB1 deficiency renders cells highly sensitive to inhibition of serine biosynthesis and DNA methylation in vitro and in vivo. Thus, we define a hypermetabolic state resulting from LKB1 loss and KRAS activation that fuels changes in the epigenetic landscape. This state is critically required for the tumourigenic program of LKB1-mutant cells, suggesting novel points of therapeutic intervention in defined patient subsets.
2016-10-24 | GSE86143 | GEO
Project description:Intermediary metabolism generates substrates for covalent modification of chromatin, enabling potential coupling of metabolic states and epigenetic control. Here, we identify such a network as a major component of oncogenic transformation downstream of the LKB1 tumour suppressor. LKB1 encodes a serine-threonine kinase that integrates nutrient availability, metabolism and growth, however the mechanisms for LKB1-dependent tumour suppression remain elusive. By developing genetically engineered mouse and primary epithelial cell models and employing transcriptional, proteomics, and metabolic analyses, we find that oncogenic cooperation between LKB1 loss and KRAS activation, alterations commonly coinciding in human cancer, is fueled by pronounced mTOR-dependent induction of the serine-glycine-one carbon network coupled to S-adenosylmethionine generation. In concert, DNA methyltransferases (DNMT1, DNMT3A) are upregulated, leading to elevation in genomic 5-methylcytosine levels, with particular enrichment at retrotransposon elements, associated with silencing of retrotransposon transcription. Correspondingly, LKB1 deficiency renders cells highly sensitive to inhibition of serine biosynthesis and DNA methylation in vitro and in vivo. Thus, we define a hypermetabolic state resulting from LKB1 loss and KRAS activation that fuels changes in the epigenetic landscape. This state is critically required for the tumourigenic program of LKB1-mutant cells, suggesting novel points of therapeutic intervention in defined patient subsets.
2016-10-24 | GSE86144 | GEO
Project description:LKB1 loss links the serine metabolic network to DNA methylation and tumourigenesis
| PRJNA340375 | ENA
Project description:Intermediary metabolism generates substrates for chromatin modification, enabling the potential coupling of metabolic and epigenetic states. Here we identify a network linking metabolic and epigenetic alterations that is central to oncogenic transformation downstream of the liver kinase B1 (LKB1, also known as STK11) tumour suppressor, an integrator of nutrient availability, metabolism and growth. By developing genetically engineered mouse models and primary pancreatic epithelial cells, and employing transcriptional, proteomics, and metabolic analyses, we find that oncogenic cooperation between LKB1 loss and KRAS activation is fuelled by pronounced mTOR-dependent induction of the serine-glycine-one-carbon pathway coupled to S-adenosylmethionine generation. At the same time, DNA methyltransferases are upregulated, leading to elevation in DNA methylation with particular enrichment at retrotransposon elements associated with their transcriptional silencing. Correspondingly, LKB1 deficiency sensitizes cells and tumours to inhibition of serine biosynthesis and DNA methylation. Thus, we define a hypermetabolic state that incites changes in the epigenetic landscape to support tumorigenic growth of LKB1-mutant cells, while resulting in potential therapeutic vulnerabilities.
| S-EPMC5988435 | biostudies-literature
Project description:Proteome maps were generated for pancreatic ductal epithelial cells from LSL KRASG12D/+ and LSL KRASG12D/+;LKB1l/l mice. The cells were isolated from the mice, and genetic lesions were induced in vitro by infection with Ade-Cre. Proteome maps were done with multiplexed proteomics using TMT10plex technology. Mass spectrometry was done on an Orbitrap Fusion using the SPS-MS3 method. Samples were TMT labeled as follows: K1-1 (126), K1-2 (129n), K2-1 (127n), K2-2 (129c), KL1-1 (127c), KL1-2 (130n), KL2-1 (128n), KL2-2 (130c).
2018-03-20 | MSV000082186 | MassIVE
Project description:The Gram-positive bacterium Bacillus subtilis uses serine not only as a building block for proteins but also as an important precursor in many anabolic reactions. Moreover, a lack of serine results in the initiation of biofilm formation. However, excess serine inhibits the growth of B. subtilis. To unravel the underlying mechanisms, we isolated suppressor mutants that can tolerate toxic serine concentrations by three targeted and non-targeted genome-wide screens. All screens as well as genetic complementation in Escherichia coli identified the so far uncharacterized permease YbeC as the major serine transporter of B. subtilis. In addition to YbeC, the threonine transporters BcaP and YbxG make minor contributions to serine uptake. A strain lacking these three transporters was able to tolerate 100 mM serine whereas the wild type strain was already inhibited by 1 mM of the amino acid. The screen for serine-resistant mutants also identified mutations that result in increased serine degradation and in increased expression of threonine biosynthetic enzymes suggesting that serine toxicity results from interference with threonine biosynthesis.
| S-EPMC8226366 | biostudies-literature
Project description:One-carbon metabolism plays a central role in a broad array of metabolic processes required for the survival and growth of tumor cells. However, the molecular basis of how one-carbon metabolism may influence RNA methylation and tumorigenesis remains largely unknown. Here we show MTHFD2, a mitochondrial enzyme involved in one-carbon metabolism, contributes to the progression of renal cell carcinoma (RCC) via a novel epitranscriptomic mechanism that involves HIF-2α. We found that expression of MTHFD2 was significantly elevated in human RCC tissues, and MTHFD2 knockdown strongly reduced xenograft tumor growth. Mechanistically, using an unbiased methylated RNA immunoprecipitation sequencing (meRIP-Seq) approach, we found that MTHFD2 plays a critical role in controlling global N6-methyladenosine (m6A) methylation levels, including the m6A methylation of HIF-2α mRNA, which results in enhanced translation of HIF-2α. Enhanced HIF-2α translation, in turn, promotes the aerobic glycolysis, linking one-carbon metabolism to HIF-2α-dependent metabolic reprogramming through RNA methylation. Our findings also suggest that MTHFD2 and HIF-2α form a positive feedforward loop in RCC, promoting metabolic reprograming and tumor growth. Taken together, our results suggest that MTHFD2 links RNA methylation status to the metabolic state of tumor cells in RCC.
| S-EPMC8040069 | biostudies-literature
Project description:One of the major metabolic changes associated with cellular transformation is enhanced nutrient utilization, which supports tumor progression by fueling both energy production and providing biosynthetic intermediates for growth. The liver kinase B1 (LKB1) is a serine/threonine kinase and tumor suppressor that couples bioenergetics to cell-growth control through regulation of mammalian target of rapamycin (mTOR) activity; however, the influence of LKB1 on tumor metabolism is not well defined. Here, we show that loss of LKB1 induces a progrowth metabolic program in proliferating cells. Cells lacking LKB1 display increased glucose and glutamine uptake and utilization, which support both cellular ATP levels and increased macromolecular biosynthesis. This LKB1-dependent reprogramming of cell metabolism is dependent on the hypoxia-inducible factor-1α (HIF-1α), which accumulates under normoxia in LKB1-deficient cells and is antagonized by inhibition of mTOR complex I signaling. Silencing HIF-1α reverses the metabolic advantages conferred by reduced LKB1 signaling and impairs the growth and survival of LKB1-deficient tumor cells under low-nutrient conditions. Together, our data implicate the tumor suppressor LKB1 as a central regulator of tumor metabolism and growth control through the regulation of HIF-1α-dependent metabolic reprogramming.
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Project description:The serine, glycine, one-carbon (SGOC) metabolic network is implicated in cancer pathogenesis, but its general functions are unknown. We carried out a computational reconstruction of the SGOC network and then characterized its expression across thousands of cancer tissues. Pathways including methylation and redox metabolism exhibited heterogeneous expression indicating a strong context dependency of their usage in tumors. From an analysis of coexpression, simultaneous up- or downregulation of nucleotide synthesis, NADPH, and glutathione synthesis was found to be a common occurrence in all cancers. Finally, we developed a method to trace the metabolic fate of serine using stable isotopes, high-resolution mass spectrometry, and a mathematical model. Although the expression of single genes didn't appear indicative of flux, the collective expression of several genes in a given pathway allowed for successful flux prediction. Altogether, these findings identify expansive and heterogeneous functions for the SGOC metabolic network in human cancer.
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Project description:RAC1 activity is critical for intestinal homeostasis, and is required for hyperproliferation driven by loss of the tumour suppressor gene Apc in the murine intestine. To avoid the impact of direct targeting upon homeostasis, we reasoned that indirect targeting of RAC1 via RAC-GEFs might be effective. Transcriptional profiling of Apc deficient intestinal tissue identified Vav3 and Tiam1 as key targets. Deletion of these indicated that while TIAM1 deficiency could suppress Apc-driven hyperproliferation, it had no impact upon tumourigenesis, while VAV3 deficiency had no effect. Intriguingly, deletion of either gene resulted in upregulation of Vav2, with subsequent targeting of all three (Vav2-/- Vav3-/- Tiam1-/-), profoundly suppressing hyperproliferation, tumourigenesis and RAC1 activity, without impacting normal homeostasis. Critically, the observed RAC-GEF dependency was negated by oncogenic KRAS mutation. Together, these data demonstrate that while targeting RAC-GEF molecules may have therapeutic impact at early stages, this benefit may be lost in late stage disease.
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