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- Küspert, Julia, et al.
(author)
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Pseudogap suppression by competition with superconductivity in La-based cuprates
- 2022
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In: Physical Review Research. - 2643-1564. ; 4:4
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Journal article (peer-reviewed)abstract
- We carried out a comprehensive high-resolution angle-resolved photoemission spectroscopy (ARPES) study of the pseudogap interplay with superconductivity in La-based cuprates. The three systems La2-xSrxCuO4, La1.6-xNd0.4SrxCuO4, and La1.8-xEu0.2SrxCuO4 display slightly different pseudogap critical points in the temperature versus doping phase diagram. We studied the pseudogap evolution into the superconducting state for doping concentrations just below the critical point. In this setting, near optimal doping for superconductivity and in the presence of the weakest possible pseudogap, we uncover how the pseudogap is partially suppressed inside the superconducting state. This conclusion is based on the direct observation of a reduced pseudogap energy scale and re-emergence of spectral weight suppressed by the pseudogap. Altogether these observations suggest that the pseudogap phenomenon in La-based cuprates is in competition with superconductivity for antinodal spectral weight.
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| 4. |
- Pudelko, L., et al.
(author)
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Erratum : Glioblastoma and glioblastoma stem cells are dependent on functional MTH1 (Oncotarget (2017) 8 (84671-84684) DOI: 10.18632/oncotarget.19404)
- 2020
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In: Oncotarget. - : Impact Journals LLC. - 1949-2553. ; 11:8
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Journal article (peer-reviewed)abstract
- This article has been corrected: The Funding information has been updated. The complete Funding list is shown below: FUNDING This work was supported by the Karolinska Institutes KID funding (LP), the Seve Ballesteros Foundation to MS, the Marie Curie foundation (CIG-618751 MS), the Knut and Alice Wallenberg Foundation (KAW2014.273 TH), the Swedish Foundation for Strategic Research (RB13-0224 TH), the Swedish Cancer Society (TH), the Swedish Research Council (2015-00162 TH), the Göran Gustafsson Foundation (TH), the Swedish Children’s Cancer Foundation (to TH), the Swedish Pain Relief Foundation (PR20140048 TH), the Torsten and Ragnar Söderberg Foundation (TH), and the European Research Council (TAROX-695376).
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| 5. |
- Pudelko, Maciej, 1978-
(author)
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Antigens derived from the mucin MUC1 : Solution and solid-phase synthesis of saccharides, peptides and glycopeptides
- 2008
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Doctoral thesis (other academic/artistic)abstract
- Mucin is a term used to describe a large family of heavily glycosylated proteins which are present on the surfaces of secretory epithelial cells and are overexpressed by many carcinomas. Membrane-bound mucin MUC1 is of special interest. Its backbone consists of repeating units of twenty amino acids with five potential glycosylation sites. These sites are expanded to structures like the T (Galβ(1->3)GalNAcα-Ser/Thr) and Tn (GalNAcα-Ser/Thr) antigens by the action of various glycosyltransferases. In different types of carcinomas these epitopes are being terminated by sialic acid residues to form among others: 2,3-sialyl-T and sialyl-Tn structures due to the elevated levels of different sialyltransferases. Solid-phase synthesis of the selected antigens derived from the mucin MUC1 has been developed and optimized. A chemoenzymatic approach has been used to effectively prepare 2,3-sialyl-T and 2,6-sialyl-Tn glycopeptides. The formation of intramolecular sialic acid lactones in presence of acetic acid was investigated. The stability of lactones formed from 2,3-sialyl-T towards water was studied using NMR spectroscopy and it appeared that 1''->2' lactone displayed remarkable strength to hydrolysis and it was suggested as a candidate for cancer vaccine. Gel-phase 19F NMR spectroscopy is known to be a very good tool to characterize resin-bound products using fluorinated protecting groups and linker molecules. The hydrophobic peptide LLLLTVLTV, which is a fragment from the MUC1 signal sequence, was prepared using solid-phase synthesis according to a modified Fmoc protocol with more active coupling reagent, stronger base, and the isopropylidene dipeptide Fmoc-Leu-Thr-(ΨMe,Mepro)-OH. Gel-phase 19F NMR spectroscopy was used to evaluate peptide chain aggregation and coupling and deprotection efficiency. A carbamate linker strategy proved to be effective in solid-phase synthesis of serine-based neoglycolipids with terminal amino functionality. Neoglycolipids were covalently bound to secondary amines in microtiter plates using squaric acid ester methodology. These arrays have potential to study the interactions between carbohydrates and e.g. proteins and microbes. The new fluorinated α-amino protective group [1-(4-(4-fluorophenyl)-2,6-dioxocyclohexylidene)ethyl] Fde was developed. This group is cleaved with hydrazine in DMF solution. By using amino acids protected with this group, it was possible to quantify the efficiency of peptide coupling using gel-phase 19F NMR spectroscopy.
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| 7. |
- Stadler, M, et al.
(author)
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Exclusion from spheroid formation identifies loss of essential cell-cell adhesion molecules in colon cancer cells
- 2018
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In: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8:1, s. 1151-
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Journal article (peer-reviewed)abstract
- Many cell lines derived from solid cancers can form spheroids, which recapitulate tumor cell clusters and are more representative of the in vivo situation than 2D cultures. During spheroid formation, a small proportion of a variety of different colon cancer cell lines did not integrate into the sphere and lost cell-cell adhesion properties. An enrichment protocol was developed to augment the proportion of these cells to 100% purity. The basis for the separation of spheroids from non-spheroid forming (NSF) cells is simple gravity-sedimentation. This protocol gives rise to sub-populations of colon cancer cells with stable loss of cell-cell adhesion. SW620 cells lacked E-cadherin, DLD-1 cells lost α-catenin and HCT116 cells lacked P-cadherin in the NSF state. Knockdown of these molecules in the corresponding spheroid-forming cells demonstrated that loss of the respective proteins were indeed responsible for the NSF phenotypes. Loss of the spheroid forming phenotype was associated with increased migration and invasion properties in all cell lines tested. Hence, we identified critical molecules involved in spheroid formation in different cancer cell lines. We present here a simple, powerful and broadly applicable method to generate new sublines of tumor cell lines to study loss of cell-cell adhesion in cancer progression.
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| 9. |
- Zhang, Si Min, et al.
(author)
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Development of a chemical probe against NUDT15
- 2020
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In: Nature Chemical Biology. - : Springer Science and Business Media LLC. - 1552-4450 .- 1552-4469. ; 16:10, s. 1120-1128
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Journal article (peer-reviewed)abstract
- The NUDIX hydrolase NUDT15 was originally implicated in sanitizing oxidized nucleotides, but was later shown to hydrolyze the active thiopurine metabolites, 6-thio-(d)GTP, thereby dictating the clinical response of this standard-of-care treatment for leukemia and inflammatory diseases. Nonetheless, its physiological roles remain elusive. Here, we sought to develop small-molecule NUDT15 inhibitors to elucidate its biological functions and potentially to improve NUDT15-dependent chemotherapeutics. Lead compound TH1760 demonstrated low-nanomolar biochemical potency through direct and specific binding into the NUDT15 catalytic pocket and engaged cellular NUDT15 in the low-micromolar range. We also employed thiopurine potentiation as a proxy functional readout and demonstrated that TH1760 sensitized cells to 6-thioguanine through enhanced accumulation of 6-thio-(d)GTP in nucleic acids. A biochemically validated, inactive structural analog, TH7285, confirmed that increased thiopurine toxicity takes place via direct NUDT15 inhibition. In conclusion, TH1760 represents the first chemical probe for interrogating NUDT15 biology and potential therapeutic avenues.
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