| 1. |
- Gad, Helge, et al.
(författare)
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MTH1 inhibition eradicates cancer by preventing sanitation of the dNTP pool
- 2014
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Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 508:7495, s. 215-221
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Tidskriftsartikel (refereegranskat)abstract
- Cancers have dysfunctional redox regulation resulting in reactive oxygen species production, damaging both DNA and free dNTPs. The MTH1 protein sanitizes oxidized dNTP pools to prevent incorporation of damaged bases during DNA replication. Although MTH1 is non-essential in normal cells, we show that cancer cells require MTH1 activity to avoid incorporation of oxidized dNTPs, resulting in DNA damage and cell death. We validate MTH1 as an anticancer target in vivo and describe small molecules TH287 and TH588 as first-in-class nudix hydrolase family inhibitors that potently and selectively engage and inhibit the MTH1 protein in cells. Protein co-crystal structures demonstrate that the inhibitors bindin the active site of MTH1. The inhibitors cause incorporation of oxidized dNTPs in cancer cells, leading to DNA damage, cytotoxicity and therapeutic responses in patient-derived mouse xenografts. This study exemplifies the non-oncogene addiction concept for anticancer treatment and validates MTH1 as being cancer phenotypic lethal.
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| 2. |
- Olsson, Bob, 1969, et al.
(författare)
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Imatinib treatment and Aβ42 in humans.
- 2014
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Ingår i: Alzheimer's & dementia : the journal of the Alzheimer's Association. - : Wiley. - 1552-5279. ; 10:5, supplement
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Tidskriftsartikel (refereegranskat)abstract
- The first-line treatment in chronic myeloid leukemia (CML), imatinib, has been shown to decrease the production of amyloid-β (Aβ) in vitro and in animal studies. However, whether imatinib has this effect in humans is not known.
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| 3. |
- Page, Brent D. G., et al.
(författare)
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Targeted NUDT5 inhibitors block hormone signaling in breast cancer cells
- 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
- With a diverse network of substrates, NUDIX hydrolases have emerged as a key family of nucleotide-metabolizing enzymes. NUDT5 (also called NUDIX5) has been implicated in ADPribose and 8-oxo-guanine metabolism and was recently identified as a rheostat of hormone-dependent gene regulation and proliferation in breast cancer cells. Here, we further elucidate the physiological relevance of known NUDT5 substrates and underscore the biological requirement for NUDT5 in gene regulation and proliferation of breast cancer cells. We confirm the involvement of NUDT5 in ADP-ribose metabolism and dissociate a relationship to oxidized nucleotide sanitation. Furthermore, we identify potent NUDT5 inhibitors, which are optimized to promote maximal NUDT5 cellular target engagement by CETSA. Lead compound, TH5427, blocks progestin-dependent, PAR-derived nuclear ATP synthesis and subsequent chromatin remodeling, gene regulation and proliferation in breast cancer cells. We herein present TH5427 as a promising, targeted inhibitor that can be used to further study NUDT5 activity and ADP-ribose metabolism.
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| 4. |
- Strömberg, Kia
(författare)
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Notch signaling : from receptor cleavage to chromatin remodeling
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- One of the principal signaling mechanisms that control development of multicellular organisms is the Notch signaling pathway. The transmembrane Notch receptor, presented at the cell surface, interacts with ligand on neighbouring cells. Ligand interaction is followed by proteolytic processing, where cleavage by the γ- secretase complex releases the intracellular (IC) part of the receptor. The Notch IC translocates to the nucleus, where it displaces co-repressors from the DNA-binding protein CSL. Notch IC in complex with CSL, mastermind, p300, PCAF and other associated proteins activate transcription of target genes, including genes of the HES and HEY families. This thesis work is focused on two specific aspects of Notch signaling: i) processing of the receptor by the γ-secretase complex and ii) the mechanisms by which the IC functions as a transcriptional activator. The γ-secretase complex, consisting of presenilin (PS), nicastrin, Aph-1 and Pen-2 proteins, processes not only the Notch receptor, but a number of other transmembrane proteins, including the amyloid precursor protein (APP). Aberrant processing of APP is implicated as a cause of Alzheimer ́s disease. Two mammalian PS homologs exist, but little is known about the degree of functional specialization of the two homologs. The incentive to address this question stems in the findings that knockout animals for the two homologs exhibit significantly different phenotypes, implicating a role for PS1, but not for PS2, in Notch signaling. In Paper I we characterize the functional similarity between complexes of various PS composition. We show that endoproteolysis, NTF-CTF interactions and the assembly and activity of γ-secretase complexes are very conserved between PS1 and PS2. The Aph-1 protein was found in genetic screens in C. elegans and has been linked to Notch signaling because of the phenotype of the loss-of-function mutant. In paper II, we analyze whether the mammalian homologs of the protein are actually part of the complex processing the Notch receptor, and whether they have a role only in complex assembly or are important also for cleavage activity. We present evidence that Aph-1 is present at the cell surface in an active γ-secretase complex, and interacts with the Notch receptor, both before and after ligand activation. Four Notch receptors are found in mammals, Notch1-4. Notch1 and 3 exhibit somewhat different properties, i.e. Notch1 is a potent activator of typical Notch regulated genes, while Notch3 is a very poor activator in the same context. Notch3 is even capable of repressing Notch1 mediated transactivation. In Paper III we explore underpinning mechanisms behind these differences. We find that Notch3 IC, like Notch1 IC, can displace the co-repressor SMRT from CSL and interacts with the SKIP and PCAF proteins. We also identify two distinct regions in the Notch IC that are critical for the difference between the Notch1 and Notch3 IC. First, the origin of the ankyrin repeat region is important, i.e. only chimeric ICs containing a Notch1 derived ankyrin repeat region are potent activators. Second, a novel region in the Notch IC, the RE/AC region (for repression/activation), is required for Notch1 IC's ability to activate and for Notch3 IC's ability to repress a HES promoter. In Paper IV we use a cell free system, with purified components of the complex and naked or chromatin reconstituted DNA to establish the importance of the individual components for activation of transcription and in what step they exert their function. Mastermind, CSL, and Notch IC are all required for optimal transcription from DNA, whereas transcription from chromatin in addition requires p300. The transcriptional activity of p300 is dependent on acetyl coenzyme A, indicating that it functions as a histone acetyltransferase when mediating Notch IC function. PCAF is unable to promote transcription on its own but enhances Notch IC mediated transcription from chromatin in conjunction with p300. These data define a critical role for p300 in the potentiation of Notch IC function by mastermind and indicate direct effects of CSL, Notch IC, and mastermind on the general transcription machinery.
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| 5. |
- Wanngren, Johanna, et al.
(författare)
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Second generation γ-secretase modulators exhibit different modulation of Notch β and Aβ production.
- 2012
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Ingår i: The Journal of biological chemistry. - 1083-351X. ; 287:39, s. 32640-50
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Tidskriftsartikel (refereegranskat)abstract
- The γ-secretase complex is an appealing drug target when the therapeutic strategy is to alter amyloid-β peptide (Aβ) aggregation in Alzheimer disease. γ-Secretase is directly involved in Aβ formation and determines the pathogenic potential of Aβ by generating the aggregation-prone Aβ42 peptide. Because γ-secretase mediates cleavage of many substrates involved in cell signaling, such as the Notch receptor, it is crucial to sustain these pathways while altering the Aβ secretion. A way of avoiding interference with the physiological function of γ-secretase is to use γ-secretase modulators (GSMs) instead of inhibitors of the enzyme. GSMs modify the Aβ formation from producing the amyloid-prone Aβ42 variant to shorter and less amyloidogenic Aβ species. The modes of action of GSMs are not fully understood, and even though the pharmacology of GSMs has been thoroughly studied regarding Aβ generation, knowledge is lacking about their effects on other substrates, such as Notch. Here, using immunoprecipitation followed by MALDI-TOF MS analysis, we found that two novel, second generation GSMs modulate both Notch β and Aβ production. Moreover, by correlating S3-specific Val-1744 cleavage of Notch intracellular domain (Notch intracellular domain) to total Notch intracellular domain levels using immunocytochemistry, we also demonstrated that Notch intracellular domain is not modulated by the compounds. Interestingly, two well characterized, nonsteroidal anti-inflammatory drugs (nonsteroidal anti-inflammatory drug), R-flurbiprofen and sulindac sulfide, affect only Aβ and not Notch β formation, indicating that second generation GSMs and nonsteroidal anti-inflammatory drug-based GSMs have different modes of action regarding Notch processing.
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