| 1. |
- Fredlund, Elina, et al.
(author)
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MOXD1 is a lineage-specific gene and a tumor suppressor in neuroblastoma
- 2024
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In: Science Advances. - 2375-2548. ; 10:25
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Journal article (peer-reviewed)abstract
- Neuroblastoma is a childhood developmental cancer; however, its embryonic origins remain poorly understood. Moreover, in-depth studies of early tumor-driving events are limited because of the lack of appropriate models. Herein, we analyzed RNA sequencing data obtained from human neuroblastoma samples and found that loss of expression of trunk neural crest–enriched gene MOXD1 associates with advanced disease and worse outcome. Further, by using single-cell RNA sequencing data of human neuroblastoma cells and fetal adrenal glands and creating in vivo models of zebrafish, chick, and mouse, we show that MOXD1 is a determinate of tumor development. In addition, we found that MOXD1 expression is highly conserved and restricted to mesenchymal neuroblastoma cells and Schwann cell precursors during healthy development. Our findings identify MOXD1 as a lineage-restricted tumor-suppressor gene in neuroblastoma, potentiating further stratification of these tumors and development of novel therapeutic interventions.
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| 2. |
- Almstedt, Elin, 1988-, et al.
(author)
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Integrative discovery of treatments for high-risk neuroblastoma
- 2020
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In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723 .- 2041-1723. ; 11:1
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Journal article (peer-reviewed)abstract
- Despite advances in the molecular exploration of paediatric cancers, approximately 50% of children with high-risk neuroblastoma lack effective treatment. To identify therapeutic options for this group of high-risk patients, we combine predictive data mining with experimental evaluation in patient-derived xenograft cells. Our proposed algorithm, TargetTranslator, integrates data from tumour biobanks, pharmacological databases, and cellular networks to predict how targeted interventions affect mRNA signatures associated with high patient risk or disease processes. We find more than 80 targets to be associated with neuroblastoma risk and differentiation signatures. Selected targets are evaluated in cell lines derived from high-risk patients to demonstrate reversal of risk signatures and malignant phenotypes. Using neuroblastoma xenograft models, we establish CNR2 and MAPK8 as promising candidates for the treatment of high-risk neuroblastoma. We expect that our method, available as a public tool (targettranslator.org), will enhance and expedite the discovery of risk-associated targets for paediatric and adult cancers.
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| 3. |
- Cerrato, Carmine P. P., et al.
(author)
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Monitoring Disassembly and Cargo Release of Phase-Separated Peptide Coacervates with Native Mass Spectrometry
- 2023
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In: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 95:29, s. 10869-10872
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Journal article (peer-reviewed)abstract
- Engineering liquid-liquid phase separation (LLPS)of proteinsand peptides holds great promise for the development of therapeuticcarriers with intracellular delivery capability but requires accuratedetermination of their assembly properties in vitro, usually with fluorescently labeled cargo. Here, we use mass spectrometry(MS) to investigate redox-sensitive coacervate microdroplets (thedense phase formed during LLPS) assembled from a short His- and Tyr-richpeptide. We can monitor the enrichment of a reduced peptide in dilutephase as the microdroplets dissolve triggered by their redox-sensitiveside chain, thus providing a quantitative readout for disassembly.Furthermore, MS can detect the release of a short peptide from coacervatesunder reducing conditions. In summary, with MS, we can monitor thedisassembly and cargo release of engineered coacervates used as therapeuticcarriers without the need for additional labels.
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| 4. |
- Colas, Kilian, et al.
(author)
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Photophysical Characteristics of Polarity-Sensitive and Lipid Droplet-Specific Phenylbenzothiadiazoles
- 2021
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In: ChemPhotoChem. - : Wiley. - 2367-0932. ; 5:7, s. 632-643
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Journal article (peer-reviewed)abstract
- In this study, we present a series of solvatochromic phenylbenzothiadiazoles that display dual emission from the locally excited (LE) and intramolecular charge transfer (ICT) excited states. The donor-acceptor derivatives are highly sensitive to polarity changes, which can be monitored by differences in emission efficiency, spectroscopic shifts and variations of the LE/ICT ratio. One of the compounds in the series, containing a thiomethyl substituent, emerged as an excellent blue emitting stain for intracellular lipid droplets, a biomarker for various types of cancer. In addition, a non-emissive nitro derivative becomes fluorescent upon bioreduction in hypoxic cancer cells and accumulates in lipid droplets with a high signal-to-background ratio.
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| 5. |
- Dimberg, Lina, 1972-
(author)
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Apoptosis Regulation in Multiple Myeloma
- 2006
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Doctoral thesis (other academic/artistic)abstract
- Multiple myeloma (MM) is a virtually incurable B cell malignancy of the bone marrow. One important part of tumor progression and an obstacle for successful therapy is resistance to apoptosis. To combat this resistance, the mechanisms of apoptosis and survival in MM must be better defined. In this thesis, we identified Fas up-regulation as a mechanism underlying interferon (IFN)-mediated sensitization to Fas-induced apoptosis in the MM cell line U-266-1970. IFN treatment induced activation of signal transducer and activator of transcription (Stat)1 but, intriguingly, also attenuated activation of MM survival factor Stat3. Exploring the role of Stat1 further, we established sub-lines of U-266-1970 with a stable over-expression of Stat1 and of its active mutant Stat1C. These sub-lines displayed a decreased expression and activation of Stat3, and an altered expression of apoptosis-related genes Harakiri, Bcl-2 and Mcl-1. In a drug library screening, Stat1 over-expression was associated with an increased sensitivity to Fas-induced apoptosis and, conversely, an increased resistance to several drugs, including the cyclin dependent kinase (cdk)1 inhibitor CGP74514A. We conclude that Stat1 over-expression does not confer a general resistance or sensitivity to apoptosis in MM, but may strongly affect the response to some specific drugs.We also explored the effects of picropodophyllin (PPP), an inhibitor of the insulin-like growth factor I (IGF-I) receptor tyrosine kinase (RTK), in MM. PPP selectively inhibited the IGF-I RTK activity without inhibiting the insulin RTK activity. Furthermore, PPP potently induced cell cycle arrest and apoptosis in all MM cell lines and patient samples tested, also in the presence of survival factors IGF-I and IL-6. We conclude that PPP has great therapeutic potential in MM Finally, we examined the expression and regulation of the inhibitors of apoptosis proteins (IAPs) in a panel of MM cell lines and patient samples. The glucocorticoid dexamethasone, which is used in MM therapy, induced a transient up-regulation and a subsequent down-regulation of c-IAP2, as well as a down-regulation of XIAP, possibly influencing the sensitivity to apoptosis induced by this drug. Supporting this notion, abrogation of IGF-IR signaling by PPP, which sensitizes MM cells to dexamethasone-induced apoptosis, enhanced the down-regulation of c-IAP2 and XIAP.
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| 6. |
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| 7. |
- Kaldmäe, Margit, et al.
(author)
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A “spindle and thread” mechanism unblocks p53 translation by modulating N-terminal disorder
- 2022
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In: Structure. - : Elsevier BV. - 0969-2126 .- 1878-4186. ; 30:5, s. 733-742, e1-e7
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Journal article (peer-reviewed)abstract
- Disordered proteins pose a major challenge to structural biology. A prominent example is the tumor suppressor p53, whose low expression levels and poor conformational stability hamper the development of cancer therapeutics. All these characteristics make it a prime example of “life on the edge of solubility.” Here, we investigate whether these features can be modulated by fusing the protein to a highly soluble spider silk domain (NT∗). The chimeric protein displays highly efficient translation and is fully active in human cancer cells. Biophysical characterization reveals a compact conformation, with the disordered transactivation domain of p53 wrapped around the NT∗ domain. We conclude that interactions with NT∗ help to unblock translation of the proline-rich disordered region of p53. Expression of partially disordered cancer targets is similarly enhanced by NT∗. In summary, we demonstrate that inducing co-translational folding via a molecular “spindle and thread” mechanism unblocks protein translation in vitro.
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| 8. |
- Ladds, Marcus J. G. W., et al.
(author)
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A DHODH inhibitor increases p53 synthesis and enhances tumor cell killing by p53 degradation blockage
- 2018
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In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 9
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Journal article (peer-reviewed)abstract
- The development of non-genotoxic therapies that activate wild-type p53 in tumors is of great interest since the discovery of p53 as a tumor suppressor. Here we report the identification of over 100 small-molecules activating p53 in cells. We elucidate the mechanism of action of a chiral tetrahydroindazole (HZ00), and through target deconvolution, we deduce that its active enantiomer (R)-HZ00, inhibits dihydroorotate dehydrogenase (DHODH). The chiral specificity of HZ05, a more potent analog, is revealed by the crystal structure of the (R)-HZ05/DHODH complex. Twelve other DHODH inhibitor chemotypes are detailed among the p53 activators, which identifies DHODH as a frequent target for structurally diverse compounds. We observe that HZ compounds accumulate cancer cells in S-phase, increase p53 synthesis, and synergize with an inhibitor of p53 degradation to reduce tumor growth in vivo. We, therefore, propose a strategy to promote cancer cell killing by p53 instead of its reversible cell cycle arresting effect.
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| 9. |
- Lama, Dilraj, et al.
(author)
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A druggable conformational switch in the c-MYC transactivation domain
- 2024
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In: Nature Communications. - : Springer Nature. - 2041-1723. ; 15:1
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Journal article (peer-reviewed)abstract
- The c-MYC oncogene is activated in over 70% of all human cancers. The intrinsic disorder of the c-MYC transcription factor facilitates molecular interactions that regulate numerous biological pathways, but severely limits efforts to target its function for cancer therapy. Here, we use a reductionist strategy to characterize the dynamic and structural heterogeneity of the c-MYC protein. Using probe-based Molecular Dynamics (MD) simulations and machine learning, we identify a conformational switch in the c-MYC amino-terminal transactivation domain (termed coreMYC) that cycles between a closed, inactive, and an open, active conformation. Using the polyphenol epigallocatechin gallate (EGCG) to modulate the conformational landscape of coreMYC, we show through biophysical and cellular assays that the induction of a closed conformation impedes its interactions with the transformation/transcription domain-associated protein (TRRAP) and the TATA-box binding protein (TBP) which are essential for the transcriptional and oncogenic activities of c-MYC. Together, these findings provide insights into structure-activity relationships of c-MYC, which open avenues towards the development of shape-shifting compounds to target c-MYC as well as other disordered transcription factors for cancer treatment. Here, the authors identify a conformational switch in the amino-terminal transactivation domain of c-MYC, termed coreMYC, which cycles between a closed, inactive state and an open, active conformation. Polyphenol epigallocatechin gallate (EGCG) is used to modulate the conformational landscape of coreMYC, stabilizing the closed and inactive conformation.
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| 10. |
- Larsson, Daniel H., et al.
(author)
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First application of liquid-metal-jet sources for small-animal imaging : High-resolution CT and phase-contrast tumor demarcation
- 2013
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In: Medical physics (Lancaster). - : Wiley. - 0094-2405 .- 2473-4209. ; 40:2, s. 021909-
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Journal article (peer-reviewed)abstract
- Purpose: Small-animal studies require images with high spatial resolution and high contrast due to the small scale of the structures. X-ray imaging systems for small animals are often limited by the microfocus source. Here, the authors investigate the applicability of liquid-metal-jet x-ray sources for such high-resolution small-animal imaging, both in tomography based on absorption and in soft-tissue tumor imaging based on in-line phase contrast. Methods: The experimental arrangement consists of a liquid-metal-jet x-ray source, the small-animal object on a rotating stage, and an imaging detector. The source-to-object and object-to-detector distances are adjusted for the preferred contrast mechanism. Two different liquid-metal-jet sources are used, one circulating a Ga/In/Sn alloy and the other an In/Ga alloy for higher penetration through thick tissue. Both sources are operated at 40-50 W electron-beam power with similar to 7 mu m x-ray spots, providing high spatial resolution in absorption imaging and high spatial coherence for the phase-contrast imaging. Results: High-resolution absorption imaging is demonstrated on mice with CT, showing 50 mu m bone details in the reconstructed slices. High-resolution phase-contrast soft-tissue imaging shows clear demarcation of mm-sized tumors at much lower dose than is required in absorption. Conclusions: This is the first application of liquid-metal-jet x-ray sources for whole-body small-animal x-ray imaging. In absorption, the method allows high-resolution tomographic skeletal imaging with potential for significantly shorter exposure times due to the power scalability of liquid-metal-jet sources. In phase contrast, the authors use a simple in-line arrangement to show distinct tumor demarcation of few-mm-sized tumors. This is, to their knowledge, the first small-animal tumor visualization with a laboratory phase-contrast system.
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