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| 2. |
- Jegerschöld, Caroline, et al.
(författare)
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Structural basis for induced formation of the inflammatory mediator prostaglandin E-2
- 2008
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 105:32, s. 11110-11115
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Tidskriftsartikel (refereegranskat)abstract
- Prostaglandins (PG) are bioactive lipids produced from arachidonic acid via the action of cyclooxygenases and terminal PG synthases. Microsomal prostaglandin E synthase 1 (MPGES1) constitutes an inducible glutathione-dependent integral membrane protein that catalyzes the oxidoreduction of cyclooxygenase derived PGH(2) into PGE(2). MPGES1 has been implicated in a number of human diseases or pathological conditions, such as rheumatoid arthritis, fever, and pain, and is therefore regarded as a primary target for development of novel antiinflammatory drugs. To provide a structural basis for insight in the catalytic mechanism, we determined the structure of MPGES1 in complex with glutathione by electron crystallography from 2D crystals induced in the presence of phospholipids. Together with results from site-directed mutagenesis and activity measurements, we can thereby demonstrate the role of specific amino acid residues. Glutathione is found to bind in a U-shaped conformation at the interface between subunits in the protein trimer. It is exposed to a site facing the lipid bilayer, which forms the specific environment for the oxidoreduction of PGH(2) to PGE(2) after displacement of the cytoplasmic half of the IN-terminal transmembrane helix. Hence, insight into the dynamic behavior of MPGES1 and homologous membrane proteins in inflammation and detoxification is provided.
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| 3. |
- Johansson, Ann-Sofie, 1967-, et al.
(författare)
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Lymphoblastic T-cell lymphoma in mice is unaffected by Celecoxib as single agent or in combination with cyclophosphamide
- 2009
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Ingår i: Leukemia and Lymphoma. - : Informa UK Limited. - 1042-8194 .- 1029-2403. ; 50:7, s. 1198-1203
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Tidskriftsartikel (refereegranskat)abstract
- Celecoxib, an inhibitor of cyclooxygenase-2, is a promising novel antitumor agent with pleitropic mechanisms of action. Whereas this drug induces growth arrest and apoptosis of B-lymphoma cells, its effect against aggressive T-cell neoplasms remains to be studied. We therefore evaluated Celecoxib therapy of immunocompetent mice transplanted with lymphoblastic T-cell lymphomas. Oral Celecoxib in clinically relevant and non-toxic doses did not affect the degree of hypersplenism or the number of viable lymphoma cells. The clinical deterioration of Celecoxib-treated mice was not different from untreated controls. The impact of adding Celecoxib (60 mg/kg) to cyclophosphamide (200 mg/kg x 1, i.p.) was assessed but showed no benefit compared to cyclophosphamide alone. Thus, Celecoxib lacks effect against lymphoblastic T-cell lymphoma in mice.
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| 4. |
- Larsson, Karin, et al.
(författare)
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Biological characterization of new inhibitors of microsomal PGE synthase-1 in preclinical models of inflammation and vascular tone
- 2019
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Ingår i: British Journal of Pharmacology. - : Wiley. - 0007-1188 .- 1476-5381. ; 176:24, s. 4625-4638
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Tidskriftsartikel (refereegranskat)abstract
- Background and Purpose Microsomal PGE synthase-1 (mPGES-1), the inducible synthase that catalyses the terminal step in PGE(2) biosynthesis, is of high interest as therapeutic target to treat inflammation. Inhibition of mPGES-1 is suggested to be safer than traditional NSAIDs, and recent data demonstrate anti-constrictive effects on vascular tone, indicating new therapeutic opportunities. However, there is a lack of potent mPGES-1 inhibitors lacking interspecies differences for conducting in vivo studies in relevant preclinical disease models. Experimental Approach Potency was determined based on the reduction of PGE(2) formation in recombinant enzyme assays, cellular assay, human whole blood assay, and air pouch mouse model. Anti-inflammatory properties were assessed by acute paw swelling in a paw oedema rat model. Effect on vascular tone was determined with human ex vivo wire myography. Key Results We report five new mPGES-1 inhibitors (named 934, 117, 118, 322, and 323) that selectively inhibit recombinant human and rat mPGES-1 with IC50 values of 10-29 and 67-250 nM respectively. The compounds inhibited PGE(2) production in a cellular assay (IC50 values 0.15-0.82 mu M) and in a human whole blood assay (IC50 values 3.3-8.7 mu M). Moreover, the compounds blocked PGE(2) formation in an air pouch mouse model and reduced acute paw swelling in a paw oedema rat model. Human ex vivo wire myography analysis showed reduced adrenergic vasoconstriction after incubation with the compounds. Conclusion and Implications These mPGES-1 inhibitors can be used as refined tools in further investigations of the role of mPGES-1 in inflammation and microvascular disease.
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| 5. |
- Pawelzik, Sven-Christian, et al.
(författare)
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Identification of Key Residues Determining Species Differences in Inhibitor Binding of Microsomal Prostaglandin E Synthase-1
- 2010
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 285:38, s. 29254-29261
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Tidskriftsartikel (refereegranskat)abstract
- Microsomal prostaglandin E synthase-1 (MPGES1) is induced during an inflammatory reaction from low basal levels by pro-inflammatory cytokines and subsequently involved in the production of the important mediator of inflammation, prostaglandin E-2. Nonsteroidal anti-inflammatory drugs prevent prostaglandin E-2 production by inhibiting the upstream enzymes cyclooxygenases 1 and 2. In contrast to these conventional drugs, a new generation of NSAIDs targets the terminal enzyme MPGES1. Some of these compounds potently inhibit human MPGES1 but do not have an effect on the rat orthologue. We investigated this interspecies difference in a rat/human chimeric form of the enzyme as well as in several mutants and identified key residues Thr-131, Leu-135, and Ala-138 in human MPGES1, which play a crucial role as gate keepers for the active site of MPGES1. These residues are situated in transmembrane helix 4, lining the entrance to the cleft between two subunits in the protein trimer, and regulate access of the inhibitor in the rat enzyme. Exchange toward the human residues in rat MPGES1 was accompanied with a gain of inhibitor activity, whereas exchange in human MPGES1 toward the residues found in rat abrogated inhibitor activity. Our data give evidence for the location of the active site at the interface between subunits in the homotrimeric enzyme and suggest a model of how the natural substratePGH(2), or competitive inhibitors of MPGES1, enter the active site via the phospholipid bilayer of the membrane.
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| 6. |
- Zirath, Hanna, et al.
(författare)
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MYC inhibition induces metabolic changes leading to accumulation of lipid droplets in tumor cells
- 2013
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Ingår i: Proceedings of the National Academy of Sciences. - : Proceedings of the National Academy of Sciences. - 1091-6490 .- 0027-8424. ; 110:25, s. 10258-10263
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Tidskriftsartikel (refereegranskat)abstract
- The MYC genes are the most frequently activated oncogenes in human tumors and are hence attractive therapeutic targets. MYCN amplification leads to poor clinical outcome in childhood neuroblastoma, yet strategies to modulate the function of MYCN do not exist. Here we show that 10058-F4, a characterized c-MYC/Max inhibitor, also targets the MYCN/Max interaction, leading to cell cycle arrest, apoptosis, and neuronal differentiation in MYCN-amplified neuroblastoma cells and to increased survival of MYCN transgenic mice. We also report the discovery that inhibition of MYC is accompanied by accumulation of intracellular lipid droplets in tumor cells as a direct consequence of mitochondrial dysfunction. This study expands on the current knowledge of how MYC proteins control the metabolic reprogramming of cancer cells, especially highlighting lipid metabolism and the respiratory chain as important pathways involved in neuroblastoma pathogenesis. Together our data support direct MYC inhibition as a promising strategy for the treatment of MYC-driven tumors.
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