| 1. |
- Gad, Helge, et al.
(author)
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MTH1 inhibition eradicates cancer by preventing sanitation of the dNTP pool
- 2014
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In: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 508:7495, s. 215-221
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Journal article (peer-reviewed)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. |
- Basu, Sankar Chandra, et al.
(author)
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Proteus: a random forest classifier to predict disorder-to-order transitioning binding regions in intrinsically disordered proteins
- 2017
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In: Journal of Computer-Aided Molecular Design. - : SPRINGER. - 0920-654X .- 1573-4951. ; 31:5, s. 453-466
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Journal article (peer-reviewed)abstract
- The focus of the computational structural biology community has taken a dramatic shift over the past one-and-a-half decades from the classical protein structure prediction problem to the possible understanding of intrinsically disordered proteins (IDP) or proteins containing regions of disorder (IDPR). The current interest lies in the unraveling of a disorder-to-order transitioning code embedded in the amino acid sequences of IDPs/ IDPRs. Disordered proteins are characterized by an enormous amount of structural plasticity which makes them promiscuous in binding to different partners, multi-functional in cellular activity and atypical in folding energy landscapes resembling partially folded molten globules. Also, their involvement in several deadly human diseases (e.g. cancer, cardiovascular and neurodegenerative diseases) makes them attractive drug targets, and important for a biochemical understanding of the disease(s). The study of the structural ensemble of IDPs is rather difficult, in particular for transient interactions. When bound to a structured partner, an IDPR adapts an ordered conformation in the complex. The residues that undergo this disorder-to-order transition are called protean residues, generally found in short contiguous stretches and the first step in understanding the modus operandi of an IDP/IDPR would be to predict these residues. There are a few available methods which predict these protean segments from their amino acid sequences; however, their performance reported in the literature leaves clear room for improvement. With this background, the current study presents Proteus, a random forest classifier that predicts the likelihood of a residue undergoing a disorder-toorder transition upon binding to a potential partner protein. The prediction is based on features that can be calculated using the amino acid sequence alone. Proteus compares favorably with existing methods predicting twice as many true positives as the second best method (55 vs. 27%) with a much higher precision on an independent data set. The current study also sheds some light on a possible disorderto-order transitioning consensus, untangled, yet embedded in the amino acid sequence of IDPs. Some guidelines have also been suggested for proceeding with a real-life structural modeling involving an IDPR using Proteus.
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| 3. |
- Dyrager, Christine, 1975, et al.
(author)
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Design, synthesis, and biological evaluation of chromone-based p38 MAP kinase inhibitors
- 2011
-
In: Journal of Medicinal Chemistry. ; 54, s. 7427-7431
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Journal article (peer-reviewed)abstract
- 3-(4-Fluorophenyl)-2-(4-pyridyl)chromone derivatives were synthesized and evaluated as p38 MAP kinase inhibitors. Introduction of an amino group in the 2-position of the pyridyl moiety gave p38α inhibitors with IC(50) in the low nanomolar range (e.g., IC(50) = 17 nm). The inhibitors showed excellent selectivity profiles when tested on a panel of 62 kinases, as well as efficient inhibition of p38 signaling in human breast cancer cells.
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| 4. |
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| 5. |
- Dyrager, Christine, et al.
(author)
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Design, Synthesis and Biological Evaluation of Chromone-based p38 MAP Kinase Inhibitors
- 2011
-
In: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 54:20, s. 7427-7431
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Journal article (peer-reviewed)abstract
- A series of 3-(4-fluorophenyl)-2-(4-pyridyl)-chromone derivs. were synthesized and evaluated as p38 MAP kinase inhibitors. Introduction of an amino group in the 2-position of the pyridyl moiety gave p38 inhibitors with IC50 values in the low nanomolar range (e.g. 8a; IC50 = 17 nm). Addnl., the inhibitors (8a and 8e) demonstrate an excellent selectivity profile towards the p38 kinase among other kinases, as well as inhibition (8e) of p38 signaling in human breast cancer cells. [on SciFinder(R)]
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| 6. |
- Henrion, Ulrike, et al.
(author)
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Tracking a complete voltage-sensor cycle with metal-ion bridges
- 2012
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In: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 109:22, s. 8552-8557
-
Journal article (peer-reviewed)abstract
- Voltage-gated ion channels open and close in response to changes in membrane potential, thereby enabling electrical signaling in excitable cells. The voltage sensitivity is conferred through four voltage-sensor domains (VSDs) where positively charged residues in the fourth transmembrane segment (S4) sense the potential. While an open state is known from the Kv1.2/2.1 X-ray structure, the conformational changes underlying voltage sensing have not been resolved. We present 20 additional interactions in one open and four different closed conformations based on metal-ion bridges between all four segments of the VSD in the voltage-gated Shaker K channel. A subset of the experimental constraints was used to generate Rosetta models of the conformations that were subjected to molecular simulation and tested against the remaining constraints. This achieves a detailed model of intermediate conformations during VSD gating. The results provide molecular insight into the transition, suggesting that S4 slides at least 12 angstrom along its axis to open the channel with a 3(10) helix region present that moves in sequence in S4 in order to occupy the same position in space opposite F290 from open through the three first closed states.
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| 7. |
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| 8. |
- Liin, Sara, et al.
(author)
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Biaryl sulfonamide motifs up- or down-regulate ion channel activity by activating voltage sensors
- 2018
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In: The Journal of General Physiology. - : ROCKEFELLER UNIV PRESS. - 0022-1295 .- 1540-7748. ; 150:8, s. 1215-1230
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Journal article (peer-reviewed)abstract
- Voltage-gated ion channels are key molecules for the generation of cellular electrical excitability. Many pharmaceutical drugs target these channels by blocking their ion-conducting pore, but in many cases, channel-opening compounds would be more beneficial. Here, to search for new channel-opening compounds, we screen 18,000 compounds with high-throughput patch-clamp technology and find several potassium-channel openers that share a distinct biaryl-sulfonamide motif. Our data suggest that the negatively charged variants of these compounds bind to the top of the voltage-sensor domain, between transmembrane segments 3 and 4, to open the channel. Although we show here that biaryl-sulfonamide compounds open a potassium channel, they have also been reported to block sodium and calcium channels. However, because they inactivate voltage-gated sodium channels by promoting activation of one voltage sensor, we suggest that, despite different effects on the channel gates, the biaryl-sulfonamide motif is a general ion-channel activator motif. Because these compounds block action potential-generating sodium and calcium channels and open an action potential-dampening potassium channel, they should have a high propensity to reduce excitability. This opens up the possibility to build new excitability-reducing pharmaceutical drugs from the biaryl-sulfonamide scaffold.
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| 9. |
- Ljungdahl, Thomas, 1974, et al.
(author)
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Positional Scanning Peptide Libraries for Kinase Substrate Specificity Determinations: Straightforward and Reproducible Synthesis Using Pentafluorophenyl Esters.
- 2010
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In: Journal of combinatorial chemistry. - : American Chemical Society (ACS). - 1520-4774 .- 1520-4766. ; 12:5, s. 733-742
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Journal article (peer-reviewed)abstract
- An efficient method to synthesize positional scanning synthetic combinatorial libraries (PS-SCLs) for studying the specificity of protein kinases is presented. Isokinetic ratios for pentafluorophenyl esters were determined iteratively using a new approach incorporating high performance liquid chromatography (HPLC) quantification and statistical experimental design. In the development process a large amount of work was put in to find efficient ways of screening for new isokinetic mixtures and to optimize the process of PS-SCL synthesis. The newly developed methods for the screening of isokinetic mixtures could be used for the screening of other interesting mixtures, but more importantly, the isokinetic ratios determined for the preactivated pentafluorophenyl esters were incorporated into a new efficient protocol. This straightforward protocol allows for a convenient synthesis of high quality PS-SCLs regardless of previous experience in solid phase synthesis.
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| 10. |
- McBean, G. J., et al.
(author)
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Redox-based therapeutics in neurodegenerative disease
- 2017
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In: British Journal of Pharmacology. - : John Wiley & Sons. - 0007-1188 .- 1476-5381. ; 174:12, s. 1750-1770
-
Journal article (peer-reviewed)abstract
- This review describes recent developments in the search for effective therapeutic agents that target redox homeostasis in neurodegenerative disease. The disruption to thiol redox homeostasis in Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and multiple sclerosis is discussed, together with the experimental strategies that are aimed at preventing, or at least minimizing, oxidative damage in these diseases. Particular attention is given to the potential of increasing antioxidant capacity by targeting the Nrf2 pathway, the development of inhibitors of NADPH oxidases that are likely candidates for clinical use, together with strategies to reduce nitrosative stress and mitochondrial dysfunction. We describe the shortcomings of compounds that hinder their progression to the clinic and evaluate likely avenues for future research.
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| 11. |
- Nilsson, Klara, et al.
(author)
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Surgical Morbidity and Mortality From the Multicenter Randomized Controlled NeoRes II Trial : Standard Versus Prolonged Time to Surgery After Neoadjuvant Chemoradiotherapy for Esophageal Cancer.
- 2020
-
In: Annals of Surgery. - : Lippincott Williams & Wilkins. - 0003-4932 .- 1528-1140. ; 272:5, s. 684-689
-
Journal article (peer-reviewed)abstract
- OBJECTIVE: To investigate if prolonged TTS after completed nCRT improves postoperative outcomes for esophageal and esophagogastric junction cancer.SUMMARY OF BACKGROUND DATA: TTS has traditionally been 4-6 weeks after completed nCRT. However, the optimal timing is not known.METHODS: A multicenter clinical trial was performed with randomized allocation of TTS of 4-6 or 10-12 weeks. The primary endpoint of this sub-study was overall postoperative complications defined as Clavien-Dindo grade II-V. Secondary endpoints included complication severity according to Clavien-Dindo grade IIIb-V, postoperative 90-day mortality, and length of hospital stay. The study was registered in Clinicaltrials.gov (NCT02415101).RESULTS: In total 249 patients were randomized. There were no significant differences between standard TTS and prolonged TTS with regard to overall incidence of complications Clavien-Dindo grade II-V (63.2% vs 72.6%, P = 0.134) or regarding Clavien-Dindo grade IIIb-V complications (31.6% vs 34.9%, P = 0.603). There were no statistically significant differences between standard and prolonged TTS regarding anastomotic leak (P = 0.596), conduit necrosis (P = 0.524), chyle leak (P = 0.427), pneumonia (P = 0.548), and respiratory failure (P = 0.723). In the standard TTS arm 5 patients (4.3%) died within 90 days of surgery, compared to 4 patients (3.8%) in the prolonged TTS arm (P = 1.0). Median length of hospital stay was 15 days in the standard TTS arm and 17 days in the prolonged TTS arm (P = 0.234).CONCLUSION: The timing of surgery after completed nCRT for carcinoma of the esophagus or esophagogastric junction, is not of major importance with regard to short-term postoperative outcomes.
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| 12. |
- Nilsson, Magnus, et al.
(author)
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Neoadjuvant Chemoradiotherapy and Surgery for Esophageal Squamous Cell Carcinoma Versus Definitive Chemoradiotherapy With Salvage Surgery as Needed : The Study Protocol for the Randomized Controlled NEEDS Trial
- 2022
-
In: Frontiers in Oncology. - : Frontiers Media S.A.. - 2234-943X. ; 12
-
Journal article (peer-reviewed)abstract
- Background: The globally dominant treatment with curative intent for locally advanced esophageal squamous cell carcinoma (ESCC) is neoadjuvant chemoradiotherapy (nCRT) with subsequent esophagectomy. This multimodal treatment leads to around 60% overall 5-year survival, yet with impaired post-surgical quality of life. Observational studies indicate that curatively intended chemoradiotherapy, so-called definitive chemoradiotherapy (dCRT) followed by surveillance of the primary tumor site and regional lymph node stations and surgery only when needed to ensure local tumor control, may lead to similar survival as nCRT with surgery, but with considerably less impairment of quality of life. This trial aims to demonstrate that dCRT, with selectively performed salvage esophagectomy only when needed to achieve locoregional tumor control, is non-inferior regarding overall survival, and superior regarding health-related quality of life (HRQOL), compared to nCRT followed by mandatory surgery, in patients with operable, locally advanced ESCC.Methods: This is a pragmatic open-label, randomized controlled phase III, multicenter trial with non-inferiority design with regard to the primary endpoint overall survival and a superiority hypothesis for the experimental intervention dCRT with regard to the main secondary endpoint global HRQOL one year after randomization. The control intervention is nCRT followed by preplanned surgery and the experimental intervention is dCRT followed by surveillance and salvage esophagectomy only when needed to secure local tumor control. A target sample size of 1200 randomized patients is planned in order to reach 462 events (deaths) during follow-up.
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| 13. |
- Page, Brent D. G., et al.
(author)
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Targeted NUDT5 inhibitors block hormone signaling in breast cancer cells
- 2018
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In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 9
-
Journal article (peer-reviewed)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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| 14. |
- Schwaiger, Christine S., et al.
(author)
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The free energy barrier for arginine gating charge translation is altered by mutations in the voltage sensor domain.
- 2012
-
In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:10, s. e45880-
-
Journal article (peer-reviewed)abstract
- The gating of voltage-gated ion channels is controlled by the arginine-rich S4 helix of the voltage-sensor domain moving in response to an external potential. Recent studies have suggested that S4 moves in three to four steps to open the conducting pore, thus visiting several intermediate conformations during gating. However, the exact conformational changes are not known in detail. For instance, it has been suggested that there is a local rotation in the helix corresponding to short segments of a 3-helix moving along S4 during opening and closing. Here, we have explored the energetics of the transition between the fully open state (based on the X-ray structure) and the first intermediate state towards channel closing (C), modeled from experimental constraints. We show that conformations within 3 Å of the X-ray structure are obtained in simulations starting from the C model, and directly observe the previously suggested sliding 3-helix region in S4. Through systematic free energy calculations, we show that the C state is a stable intermediate conformation and determine free energy profiles for moving between the states without constraints. Mutations indicate several residues in a narrow hydrophobic band in the voltage sensor contribute to the barrier between the open and C states, with F233 in the S2 helix having the largest influence. Substitution for smaller amino acids reduces the transition cost, while introduction of a larger ring increases it, largely confirming experimental activation shift results. There is a systematic correlation between the local aromatic ring rotation, the arginine barrier crossing, and the corresponding relative free energy. In particular, it appears to be more advantageous for the F233 side chain to rotate towards the extracellular side when arginines cross the hydrophobic region.
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| 15. |
- Silverå Ejneby, Malin, 1987-, et al.
(author)
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Coupling stabilizers open KV1-type potassium channels
- 2020
-
In: Proceedings of the National Academy of Sciences of the United States of America. - Washington, DC, United States : The National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 117:43, s. 27016-27021
-
Journal article (peer-reviewed)abstract
- The opening and closing of voltage-gated ion channels are regulated by voltage sensors coupled to a gate that controls the ion flux across the cellular membrane. Modulation of any part of gating constitutes an entry point for pharmacologically regulating channel function. Here, we report on the discovery of a large family of warfarin-like compounds that open the two voltage-gated type 1 potassium (KV1) channels KV1.5 and Shaker, but not the related KV2-, KV4-, or KV7-type channels. These negatively charged compounds bind in the open state to positively charged arginines and lysines between the intracellular ends of the voltage-sensor domains and the pore domain. This mechanism of action resembles that of endogenous channel-opening lipids and opens up an avenue for the development of ion-channel modulators.
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| 16. |
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| 17. |
- Wallner, Fredrik, 1975-
(author)
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Glycoconjugates : Solid-phase synthesis and biological applications
- 2005
-
Doctoral thesis (other academic/artistic)abstract
- Glycoconjugates are biologically important molecules with diverse functions. They consist of carbohydrates of varying size and complexity, attached to a non-sugar moiety as a lipid or a protein. Glycoconjugate structures are often very complex and their intricate biosynthetic pathways makes overexpression difficult. This renders the isolation of pure, structurally defined compounds from natural sources cumbersome. Therefore, to better address questions in glycobiology, synthetic glycoconjugates are an appealing alternative. In addition, synthetic methods allow for the preparation of non-natural glycoconjugates that can enhance the understanding of the influence of structural features on the biological responses. In this thesis, synthetic methods for the preparation of glycoconjugates, especially glycolipid analogues, have been developed. These methods make use of solid-phase chemistry and are amenable to library synthesis of series of similar compounds. Solid-phase synthesis is a technique where the starting material of the reaction is attached to small plastic beads through a linker. This allows large excess of reagents to speed up the reactions and the sometimes difficult purifications of intermediate products are reduced to simple washings of the beads. One problem with solid-phase synthesis is the difficulties to monitor the reactions and characterize the intermediate products. Gel-phase 19 F-NMR spectroscopy, using fluorinated linkers and protecting groups, is an excellent tool to overcome this problem and to monitor solid-phase synthesis of e.g. glycoconjugates. Two novel fluorinated linkers for the attachment of carboxylic acids have been developed and are presented in the thesis. These linkers can be cleaved with both acids of varying strengths and nucleophiles like hydroxide ions, and they are stable to glycosylation conditions. In addition, a novel filter reactor for solid-phase synthesis was designed. The reactor fits into an ordinary NMR spectrometer to facilitate the reaction monitoring with gel-phase 19 F-NMR spectroscopy. The biological applications of the synthesized glycolipids were demonstrated in two different settings. The CD1d restricted binding of glycolipids carrying the monosaccharide α-GalNAc as carbohydrate could be detected on viable cells of mouse origin. CD1d is one of several antigen presenting molecules (the CD1 proteins) that presents lipids and glycolipids to circulating T-cells that in turn can initiate an immune response. The CD1 molecules are relatively sparsely investigated, and the method to measure glycolipid binding on viable cells, as described in the thesis, has the possibility to greatly enhance the knowledge of the structural requirements for CD1-binding. Serine-based neoglycolipids with terminal carboxylic acids were used to prepare glycoconjugate arrays with covalent bonds to secondary amines on microtiter plates. Carbohydrate arrays have great possibilities to simplify the study of interactions between carbohydrates and e.g. proteins and microbes. The usefulness of the glycolipid arrays constructed in the thesis was illustrated with two lectins, RCA120 from Ricinus communis and BS-1 from Bandeiraea simplicifolia. Both lectins bound to the array of neoglycolipids in agreement with their respective specificity for galactosides. Glycobiology is a large area of great interest and the methods described in this thesis can be used to answer a variety of glycoconjugaterelated biological questions.
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| 18. |
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| 19. |
- Wallner, Fredrik K., et al.
(author)
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Correlation and cluster analysis of immunomodulatory drugs based on cytokine profiles
- 2018
-
In: Pharmacological Research. - : Elsevier. - 1043-6618 .- 1096-1186. ; 128, s. 244-251
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Journal article (peer-reviewed)abstract
- Drug discovery is a constant struggle to overcome hurdles posed by the complexity of biological systems. One of these hurdles is to find and understand the molecular target and the biological mechanism of action. Although the molecular target has been determined, the true biological effect may be unforeseen also for well-established drugs. Hence, there is a need for novel ways to increase the knowledge of the biological effects of drugs in the developmental process. In this study, we have determined cytokine profiles for 26 non-biological immunomodulatory drugs or drug candidates and used these profiles to cluster the compounds according to their effect in a preclinical ex vivo culture model of arthritis. This allows for prediction of functions and drug target of a novel drug candidate based on profiles obtained in this study. Results from the study showed that the JAK inhibitors tofacitinib and ruxolitinib formed a robust cluster and were found to have a distinct cytokine profile compared to the other drugs. Another robust cluster included the calcineurin inhibitors cyclosporine A and tacrolimus and the protein kinase inhibitors fostamatinib disodium and sotrastaurin acetate, which caused a strong overall inhibition of the cytokine production. The results of this methodology indicate that cytokine profiles can be used to provide a fingerprint-like identification of a drug as a tool to benchmark novel drugs and to improve descriptions of mode of action.
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| 20. |
- Wallner, Fredrik K., et al.
(author)
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Cytokine correlation analysis based on drug perturbation
- 2017
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In: Cytokine. - : Elsevier. - 1043-4666 .- 1096-0023. ; 90, s. 73-79
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Journal article (peer-reviewed)abstract
- Cytokines and chemokines play a crucial role in regulating the immune system. Understanding how these molecules are co-regulated is important to understand general immunology, and particularly their role in clinical applications such as development and evaluation of novel drug therapies. Cytokines are today widely used as therapeutic targets and as biomarkers to monitor effects of drug therapies and for prognosis and diagnosis of diseases. Therapies that target a specific cytokine are also likely to affect the production of other cytokines due to their cross-regulatory functions and because the cytokines are produced by common cell types. In this study, we have perturbated the production of 17 different cytokines in a preclinical rat model of autoimmune arthritis, using 55 commercially available immunomodulatory drugs and clinical candidates. The majority of the studied drugs was selected for their anti-inflammatory role and was confirmed to inhibit the production of IL-2 and IFN-γ in this model but was also found to increase the production of other cytokines compared to the untreated control. Correlation analysis identified 58 significant pairwise correlations between the cytokines. The strongest correlations found in this study were between IL-2 and IFN-γ (r=0.87) and between IL-18 and EPO (r=0.84). Cluster analysis identified two robust clusters: (1) IL-7, IL-18 and EPO, and (2) IL-2, IL-17 and IFN-γ. The results show that cytokines are highly co-regulated, which provide valuable information for how a therapeutic drug might affect clusters of cytokines. In addition, a cytokine that is used as a therapeutic biomarker could be combined with its related cytokines into a biomarker panel to improve diagnostic accuracy.
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| 21. |
- Wallner, Fredrik K., et al.
(author)
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Loading of the antigen-presenting protein CD1d with synthetic glycolipids
- 2004
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In: ChemBioChem. - Weinheim : Wiley-VCH. - 1439-4227 .- 1439-7633. ; 5:4, s. 437-444
-
Journal article (peer-reviewed)abstract
- CD1 proteins present mammalian and microbial lipid and glycolipid antigens to different subsets of T cells. Few such antigens have been identified and the binding of these to CD1 molecules has mainly been studied by using responding T cells in cellular assays or recombinant solid-phase CD1 proteins. In the present study we use four different glycolipids, some of which contain tumor-associated carbohydrate antigens, to develop a procedure to easily detect binding of glycolipids to CD1 proteins on viable cells. Two of these glycolipids are novel glycoconjugates containing -D-N-acetylgalactosamine (-GalNAc) that were prepared by a combined solution and solid-phase approach. The key step, a Fischer glycosylation of 9-fluorenylmethoxycarbonylaminoethanol with GalNAc, furnished the -glycoside 4 in 34 % yield. Cells were incubated with glycolipids and stained with monoclonal antibodies specific for the carbohydrate part. The level of glycolipid bound to cells was then determined by flow cytometry with a secondary antibody labeled with fluorescein isothiocyanate. All four glycolipids were found to bind to CD1d but with different selectivity. The loading was dose dependent and could be inhibited by an established CD1d ligand, -galactosylceramide. Through use of this procedure, glycolipids were selectively loaded onto CD1d expressed on professional antigen-presenting cells for future use as cellular vaccines. Moreover, the glycolipids described in this study represent novel CD1d-binding ligands that will be useful derivatives in the study of CD1d-dependent immune responses, for example, against tumors.
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| 22. |
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| 23. |
- Wallner, Fredrik K., et al.
(author)
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Solid-phase synthesis of serine-based glycosphingolipid analogues for preparation of glycoconjugate arrays
- 2005
-
In: Organic and biomolecular chemistry. - London : Royal Society of Chemistry. - 1477-0520 .- 1477-0539. ; 3:2, s. 309-315
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Journal article (peer-reviewed)abstract
- Synthetic glycolipids with defined structures are important tools in the study of glycolipid biology. In this paper we describe a solid-phase synthesis of three galactosylated serine-based glycosphingolipid analogues using the novel linker 2-fluoro-4-(hydroxymethyl)-phenoxyacetic acid. Gel-phase 19F-NMR spectroscopy was used to measure the yield and stereochemical outcome of the solid-phase glycosylations. Under NIS–TfOH promotion, α- and β-selective glycosylations were performed at room temperature with thioglycoside donors carrying fluorine labelled protective groups. Finally, the glycolipids were covalently linked to microtiter plates and labelled lectins with different selectivity for α- and β-galactosides could bind to the glycolipid arrays.
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| 24. |
- Wallner, Fredrik K, et al.
(author)
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Synthesis and evaluation of 2-(2-fluoro-4-hydroxymethyl-5-methoxy-phenoxy)acetic acid as a linker in solid-phase synthesis monitored by gel-phase 19F NMR spectroscopy
- 2007
-
In: Organic and biomolecular chemistry. - : The Royal Society of Chemistry. - 1477-0520 .- 1477-0539. ; 5, s. 2464-2471
-
Journal article (peer-reviewed)abstract
- Gel-phase 19F NMR spectroscopy is a useful monitoring technique for solid-phase organic chemistry due to the high information content it delivers and swift acquisition times, using standard NMR spectrometers. This paper describes the synthesis of the novel linker 2-(2-fluoro-4-hydroxymethyl-5-methoxy-phenoxy)acetic acid in 29% yield over seven steps, using nucleophilic aromatic substitutions on 2,4,5-trifluorobenzonitrile as key steps. Following standard solid-phase synthesis a peptide could be cleaved from the linker using 20% TFA in CH2Cl2 in 30 minutes, in contrast to a previously described monoalkoxy linker that requires 90% TFA in water at elevated temperature. A resin-bound peptide could be successfully glycosylated using only two equivalents of a thioglycoside donor, activated with N-iodosuccinimide and trifluoromethanesulfonic acid, and subsequent cleavage and deprotection gave the target glycopeptide. Direct glycosylation of the linker itself followed by mild acidic cleavage gave a fully protected hemiacetal for further chemical manipulation.
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