| 1. |
- Gustafsson, Nina M. S., et al.
(författare)
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Targeting PFKFB3 radiosensitizes cancer cells and suppresses homologous recombination
- 2018
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- The glycolytic PFKFB3 enzyme is widely overexpressed in cancer cells and an emerging anticancer target. Here, we identify PFKFB3 as a critical factor in homologous recombination (HR) repair of DNA double-strand breaks. PFKFB3 rapidly relocates into ionizing radiation (IR)-induced nuclear foci in an MRN-ATM-gamma H2AX-MDC1-dependent manner and co-localizes with DNA damage and HR repair proteins. PFKFB3 relocalization is critical for recruitment of HR proteins, HR activity, and cell survival upon IR. We develop KAN0438757, a small molecule inhibitor that potently targets PFKFB3. Pharmacological PFKFB3 inhibition impairs recruitment of ribonucleotide reductase M2 and deoxynucleotide incorporation upon DNA repair, and reduces dNTP levels. Importantly, KAN0438757 induces radiosensitization in transformed cells while leaving non-transformed cells unaffected. In summary, we identify a key role for PFKFB3 enzymatic activity in HR repair and present KAN0438757, a selective PFKFB3 inhibitor that could potentially be used as a strategy for the treatment of cancer.
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| 2. |
- Bonagas, Nadilly, et al.
(författare)
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Pharmacological targeting of MTHFD2 suppresses acute myeloid leukemia by inducing thymidine depletion and replication stress
- 2022
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Ingår i: NATURE CANCER. - : Springer Science and Business Media LLC. - 2662-1347. ; 3:2, s. 156-
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Tidskriftsartikel (refereegranskat)abstract
- The folate metabolism enzyme MTHFD2 (methylenetetrahydrofolate dehydrogenase/cyclohydrolase) is consistently overexpressed in cancer but its roles are not fully characterized, and current candidate inhibitors have limited potency for clinical development. In the present study, we demonstrate a role for MTHFD2 in DNA replication and genomic stability in cancer cells, and perform a drug screen to identify potent and selective nanomolar MTHFD2 inhibitors; protein cocrystal structures demonstrated binding to the active site of MTHFD2 and target engagement. MTHFD2 inhibitors reduced replication fork speed and induced replication stress followed by S-phase arrest and apoptosis of acute myeloid leukemia cells in vitro and in vivo, with a therapeutic window spanning four orders of magnitude compared with nontumorigenic cells. Mechanistically, MTHFD2 inhibitors prevented thymidine production leading to misincorporation of uracil into DNA and replication stress. Overall, these results demonstrate a functional link between MTHFD2-dependent cancer metabolism and replication stress that can be exploited therapeutically with this new class of inhibitors. Helleday and colleagues describe a nanomolar MTHFD2 inhibitor that causes replication stress and DNA damage accumulation in cancer cells via thymidine depletion, demonstrating a potential therapeutic strategy in AML tumors in vivo.
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| 3. |
- Cao, Hao
(författare)
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Bis-(2-ethylhexyl) Phthalate Increases Insulin Expression and Lipid Levels in Drosophila melanogaster
- 2016
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Ingår i: Basic & Clinical Pharmacology & Toxicology. - : Wiley. - 1742-7835 .- 1742-7843.
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Tidskriftsartikel (refereegranskat)abstract
- Bis-(2-ethylhexyl) phthalate (DEHP) is one of the most widely used plasticizers, and human beings are exposed toDEHP via polyvinyl chloride (PVC) materials, medical equipment and even drinking water. While DEHP has been implicated to influence metabolism and endocrine functions, important questions remain about the molecular mechanisms of these effects. We employed the model organism Drosophila melanogaster and examined physiological, molecular and behavioural effects fromDEHP-contaminated food. We found that DEHP, at levels comparable to human exposure, made male flies more resistant to starvation and increased lipid levels, while decreasing circulating carbohydrates. Moreover, DEHP-fed male flies had higher expression levels of an insulin-like peptide known to regulate metabolism, as well as the insulin receptor. Our results suggest that long term DEHP feeding may induce diabetes-like dysfunctions. These findings provide a molecular background of how DEHP mayhave detrimental effects on metabolic functions.
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| 4. |
- Green, Alanna C., et al.
(författare)
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Formate overflow drives toxic folate trapping in MTHFD1 inhibited cancer cells
- 2023
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Ingår i: Nature Metabolism. - : Springer Nature. - 2522-5812. ; 5:4, s. 642-659
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Tidskriftsartikel (refereegranskat)abstract
- Cancer cells fuel their increased need for nucleotide supply by upregulating one-carbon (1C) metabolism, including the enzymes methylenetetrahydrofolate dehydrogenase–cyclohydrolase 1 and 2 (MTHFD1 and MTHFD2). TH9619 is a potent inhibitor of dehydrogenase and cyclohydrolase activities in both MTHFD1 and MTHFD2, and selectively kills cancer cells. Here, we reveal that, in cells, TH9619 targets nuclear MTHFD2 but does not inhibit mitochondrial MTHFD2. Hence, overflow of formate from mitochondria continues in the presence of TH9619. TH9619 inhibits the activity of MTHFD1 occurring downstream of mitochondrial formate release, leading to the accumulation of 10-formyl-tetrahydrofolate, which we term a ‘folate trap’. This results in thymidylate depletion and death of MTHFD2-expressing cancer cells. This previously uncharacterized folate trapping mechanism is exacerbated by physiological hypoxanthine levels that block the de novo purine synthesis pathway, and additionally prevent 10-formyl-tetrahydrofolate consumption for purine synthesis. The folate trapping mechanism described here for TH9619 differs from other MTHFD1/2 inhibitors and antifolates. Thus, our findings uncover an approach to attack cancer and reveal a regulatory mechanism in 1C metabolism.
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| 5. |
- Karsten, Stella, et al.
(författare)
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MTH1 as a target to alleviate T cell driven diseases by selective suppression of activated T cells
- 2021
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Ingår i: Cell Death & Differentiation. - Stockholm : Karolinska Institutet, Dept of Oncology-Pathology. - 1350-9047 .- 1476-5403.
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Tidskriftsartikel (refereegranskat)abstract
- T cell-driven diseases account for considerable morbidity and disability globally and there is an urgent need for new targeted therapies. Both cancer cells and activated T cells have an altered redox balance, and up-regulate the DNA repair protein MTH1 that sanitizes the oxidized nucleotide pool to avoid DNA damage and cell death. Herein we suggest that the up-regulation of MTH1 in activated T cells correlates with their redox status, but occurs before the ROS levels increase, challenging the established conception of MTH1 increasing as a direct response to an increased ROS status. We also propose a heterogeneity in MTH1 levels among activated T cells, where a smaller subset of activated T cells does not upregulate MTH1 despite activation and proliferation. The study suggests that the vast majority of activated T cells have high MTH1 levels and are sensitive to the MTH1 inhibitor TH1579 (Karonudib) via induction of DNA damage and cell cycle arrest. TH1579 further drives the surviving cells to the MTH1[superscript low] phenotype with altered redox status. TH1579 does not affect resting T cells, as opposed to the established immunosuppressor Azathioprine, and no sensitivity among other major immune cell types regarding their function can be observed. Finally, we demonstrate a therapeutic effect in a murine model of experimental autoimmune encephalomyelitis. In conclusion, we show proof of concept of the existence of MTH1[superscript high] and MTH1[superscript low] activated T cells, and that MTH1 inhibition by TH1579 selectively suppresses pro-inflammatory activated T cells. Thus, MTH1 inhibition by TH1579 may serve as a novel treatment option against autoreactive T cells in autoimmune diseases, such as multiple sclerosis.
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| 6. |
- Marttila, Petra
(författare)
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Targeting MTHFD1 and MTHFD2 as cancer treatment
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- One-carbon (1C) metabolism provides building blocks for nucleotide synthesis and therefore plays a central role in DNA replication and repair. To sustain rapid proliferation, cancer cells often upregulate their 1C metabolism, including the enzymes MTHFD1 and MTHFD2, as a part of their metabolic rewiring. Previously, MTHFD2 in particular has been indicated as a potential drug target, mainly due to its cancer-enriched expression profile. Interestingly, both MTHFD1 and MTHFD2 have also emerging nuclear functions besides their canonical metabolic activities in the 1C pathway. However, the nuclear localization of MTHFD2 and its role in the DNA damage response are not well understood. Moreover, evaluation of the therapeutic potential of targeting MTHFD1 and MTHFD2 in cancer is hampered by the lack of potent inhibitors of these enzymes. In this thesis, we aimed to develop small-molecule MTHFD1/2 inhibitors and characterize their mechanism of action, as well as study the nuclear role of MTHFD2 in DNA repair. In Paper I, we develop a series of small-molecule MTHFD1/2 inhibitors, including TH9619. We study the mechanism of action of these inhibitors and show that they cause thymidylate depletion, followed by excessive misincorporation of uracil into DNA, induction of replication stress and cell death in acute myeloid leukemia cells. These new inhibitors selectively induced apoptosis in leukemia cells while largely sparing nontumorigenic cells and displayed efficacy in a mouse xenograft model of acute myeloid leukemia. In Paper II, we further investigate the mechanism of action of MTHFD1/2 inhibitors, focusing on TH9619. We reveal that TH9619 engages with nuclear MTHFD2 but does not disrupt formate overflow from mitochondria since it cannot target mitochondrial MTHFD2. Mechanistically, TH9619 caused accumulation of 10-formyl-tetrahydrofolate downstream of mitochondrial formate release due to its inhibition of MTHFD1. Trapping of 10-formyl-tetrahydrofolate ultimately led to thymidylate depletion and cell death in MTHFD2-expressing colorectal cancer cells. Lastly, in Paper III, we identify a nuclear role of MTHFD2 in the early steps of DNA double-strand break repair in cancer cells. We found that MTHFD2 rapidly accumulated in the nucleus following ionizing radiation, which was mediated by the ATM and DNA-PK kinases, and co-localized with DNA damage sites. Depletion of MTHFD2 led to impaired phosphorylation of BRCA1, defective DNA end resection and decreased HR and NHEJ repair activity. Moreover, inhibition of MTHFD2 with TH9619 exacerbated DNA damage after irradiation in repair-proficient cancer cells and synergized with PARP inhibitors. In conclusion, this thesis details the complex mechanism of action of MTHFD1/2 inhibitors and highlights their therapeutic potential in cancer. Our work also demonstrates a critical role of MTHFD2 in facilitating double-strand break repair.
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| 7. |
- Škerlová, Jana, et al.
(författare)
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Crystal structures of human PAICS reveal substrate and product binding of an emerging cancer target
- 2020
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 295:33, s. 11656-11668
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Tidskriftsartikel (refereegranskat)abstract
- The bifunctional human enzyme phosphoribosylaminoimidazole carboxylase and phosphoribosylaminoimidazolesuccinocarboxamide synthetase (PAICS) catalyzes two essential steps in the de novo purine biosynthesis pathway. PAICS is overexpressed in many cancers and could be a promising target for the development of cancer therapeutics. Here, using gene knockdowns and clonogenic survival and cell viability assays, we demonstrate that PAICS is required for growth and survival of prostate cancer cells. PAICS catalyzes the carboxylation of aminoimidazole ribonucleotide (AIR) and the subsequent conversion of carboxyaminoimidazole ribonucleotide (CAIR) and l-aspartate to N-succinylcarboxamide-5-aminoimidazole ribonucleotide (SAICAR). Of note, we present the first structures of human octameric PAICS in complexes with native ligands. In particular, we report the structure of PAICS with CAIR bound in the active sites of both domains and SAICAR bound in one of the SAICAR synthetase domains. Moreover, we report the PAICS structure with SAICAR and an ATP analog occupying the SAICAR synthetase active site. These structures provide insight into substrate and product binding and the architecture of the active sites, disclosing important structural information for rational design of PAICS inhibitors as potential anticancer drugs.
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