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Macion A, Schäfer R. Ionization potentials of metal clusters studied with a broad range, tunable vacuum ultraviolet light source. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2023; 94:063101. [PMID: 37862487 DOI: 10.1063/5.0151238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 05/11/2023] [Indexed: 10/22/2023]
Abstract
In this work, we present an alternative to complex laser setups or synchrotron light sources to accurately measure the ionization potentials of metal clusters. The setup is based on a commercial Xe flash lamp, combined with a vacuum monochromator, and has been applied to determine the ionization potentials of Snn clusters with n = 8-12 atoms. The uncertainty in the determination of the ionization potentials is mainly caused by the bandwidth of the monochromator. The adiabatic ionization potentials (AIPs) are extracted from experimental photoionization efficiency curves. Franck-Condon simulations are additionally used to interpret the shape and onset of the photo-ion yield. The obtained AIPs are (all energies are in eV) Sn8 (6.53 ± 0.05), Sn9 (6.69 ± 0.04), Sn10 (6.93 ± 0.03), Sn11 (6.34 ± 0.05), and Sn12 (IsoI 6.64 ± 0.04 and IsoIII 6.36 ± 0.05). Furthermore, the impact of multiple isomers present in the experiment on the photo-ion yield is addressed and compared with other experimental data in the literature.
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Motta S, Christensen JB, Togno M, Schäfer R, Safai S, Lomax AJ, Yukihara EG. Characterization of LiF:Mg,Ti thermoluminescence detectors in low-LET proton beams at ultra-high dose rates. Phys Med Biol 2023; 68. [PMID: 36696696 DOI: 10.1088/1361-6560/acb634] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 01/25/2023] [Indexed: 01/26/2023]
Abstract
Objective.This work aims at characterizing LiF:Mg,Ti thermoluminescence detectors (TLDs) for dosimetry of a 250 MeV proton beam delivered at ultra-high dose rates (UHDR). Possible dose rate effects in LiF:Mg,Ti, as well as its usability for dosimetry of narrow proton beams are investigated.Approach.LiF:Mg,Ti (TLD-100TMMicrocubes, 1 mm × 1 mm × 1 mm) was packaged in matrices of 5 × 5 detectors. The center of each matrix was irradiated with single-spot low-LET (energy >244 MeV) proton beam in the (1-4500) Gy s-1average dose rates range. A beam reconstruction procedure was applied to the detectors irradiated at the highest dose rate (Gaussian beam sigma <2 mm) to correct for volumetric averaging effects. Reference dosimetry was carried out with a diamond detector and radiochromic films. The delivered number of protons was measured by a Faraday cup, which was employed to normalize the detector responses.Main results.The lateral beam spread obtained from the beam reconstruction agreed with the one derived from the radiochromic film measurements. No dose rates effects were observed in LiF:Mg,Ti for the investigated dose rates within 3% (k= 1). On average, the dose response of the TLDs agreed with the reference detectors within their uncertainties. The largest deviation (-5%) was measured at 4500 Gy s-1.Significance.The dose rate independence of LiF:Mg,Ti TLDs makes them suitable for dosimetry of UHDR proton beams. Additionally, the combination of a matrix of TLDs and the beam reconstruction can be applied to determine the beam profile of narrow proton beams.
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Togno M, Nesteruk KP, Schäfer R, Psoroulas S, Meer D, Grossmann M, Christensen JB, Yukihara EG, Lomax AJ, Weber DC, Safai S. Ultra-high dose rate dosimetry for pre-clinical experiments with mm-small proton fields. Phys Med 2022; 104:101-111. [PMID: 36395638 DOI: 10.1016/j.ejmp.2022.10.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 10/10/2022] [Accepted: 10/23/2022] [Indexed: 11/15/2022] Open
Abstract
PURPOSE To characterize an experimental setup for ultra-high dose rate (UHDR) proton irradiations, and to address the challenges of dosimetry in millimetre-small pencil proton beams. METHODS At the PSI Gantry 1, high-energy transmission pencil beams can be delivered to biological samples and detectors up to a maximum local dose rate of ∼9000 Gy/s. In the presented setup, a Faraday cup is used to measure the delivered number of protons up to ultra-high dose rates. The response of transmission ion-chambers, as well as of different field detectors, was characterized over a wide range of dose rates using the Faraday cup as reference. RESULTS The reproducibility of the delivered proton charge was better than 1 % in the proposed experimental setup. EBT3 films, Al2O3:C optically stimulated luminescence detectors and a PTW microDiamond were used to validate the predicted dose. Transmission ionization chambers showed significant volume ion-recombination (>30 % in the tested conditions) which can be parametrized as a function of the maximum proton current density. Over the considered range, EBT3 films, inorganic scintillator-based screens and the PTW microDiamond were demonstrated to be dose rate independent within ±3 %, ±1.8 % and ±1 %, respectively. CONCLUSIONS Faraday cups are versatile dosimetry instruments that can be used for dose estimation, field detector characterization and on-line dose verification for pre-clinical experiments in UHDR proton pencil beams. Among the tested detectors, the commercial PTW microDiamond was found to be a suitable option to measure real time the dosimetric properties of narrow pencil proton beams for dose rates up to 2.2 kGy/s.
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Leyvraz S, Schütte M, Kessler T, Lamping M, Burock S, Ochsenreither S, Amstislavskiy V, Risch T, Jelas I, Ulrich C, Dobos G, Klauschen F, Schäfer R, Lange B, Klinghammer K, Yaspo ML, Keilholz U. 847P Precision oncology for resistant acral, mucosal and cutaneous melanomas: A prospective broad high throughput genomics feasibility study. Ann Oncol 2022. [DOI: 10.1016/j.annonc.2022.07.973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Hu B, Lelek S, Spanjaard B, El-Sammak H, Simões MG, Mintcheva J, Aliee H, Schäfer R, Meyer AM, Theis F, Stainier DYR, Panáková D, Junker JP. Origin and function of activated fibroblast states during zebrafish heart regeneration. Nat Genet 2022; 54:1227-1237. [PMID: 35864193 PMCID: PMC7613248 DOI: 10.1038/s41588-022-01129-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 06/09/2022] [Indexed: 12/12/2022]
Abstract
The adult zebrafish heart has a high capacity for regeneration following injury. However, the composition of the regenerative niche has remained largely elusive. Here, we dissected the diversity of activated cell states in the regenerating zebrafish heart based on single-cell transcriptomics and spatiotemporal analysis. We observed the emergence of several transient cell states with fibroblast characteristics following injury, and we outlined the proregenerative function of collagen-12-expressing fibroblasts. To understand the cascade of events leading to heart regeneration, we determined the origin of these cell states by high-throughput lineage tracing. We found that activated fibroblasts were derived from two separate sources: the epicardium and the endocardium. Mechanistically, we determined Wnt signalling as a regulator of the endocardial fibroblast response. In summary, our work identifies specialized activated fibroblast cell states that contribute to heart regeneration, thereby opening up possible approaches to modulating the regenerative capacity of the vertebrate heart. Single-cell RNA sequencing and spatiotemporal analysis of the regenerating zebrafish heart identify transient proregenerative fibroblast-like cells that are derived from the epicardium and the endocardium. Wnt signalling regulates the endocardial fibroblast response.
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Borsato M, Cid Vidal X, Tsai Y, Vázquez Sierra C, Zurita J, Alonso-Álvarez G, Boyarsky A, Brea Rodríguez A, Buarque Franzosi D, Cacciapaglia G, Casais Vidal A, Du M, Elor G, Escudero M, Ferretti G, Flacke T, Foldenauer P, Hajer J, Henry L, Ilten P, Kamenik J, Kishor Jashal B, Knapen S, Kostiuk I, Redi FL, Low M, Liu Z, Oyanguren Campos A, Polycarpo E, Ramos M, Ramos Pernas M, Salvioni E, Rangel MS, Schäfer R, Sestini L, Soreq Y, Tran VQ, Timiryasov I, van Veghel M, Westhoff S, Williams M, Zupan J. Unleashing the full power of LHCb to probe stealth new physics. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2022; 85:024201. [PMID: 34942603 DOI: 10.1088/1361-6633/ac4649] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Accepted: 12/23/2021] [Indexed: 06/14/2023]
Abstract
In this paper, we describe the potential of the LHCb experiment to detect stealth physics. This refers to dynamics beyond the standard model that would elude searches that focus on energetic objects or precision measurements of known processes. Stealth signatures include long-lived particles and light resonances that are produced very rarely or together with overwhelming backgrounds. We will discuss why LHCb is equipped to discover this kind of physics at the Large Hadron Collider and provide examples of well-motivated theoretical models that can be probed with great detail at the experiment.
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Willer H, Thielemann C, Elvers-Hornung S, Spohn G, Delorme, Giesen M, Schäfer R, Bieback K. Repeated administration of human bone marrow derived MSC expanded in virally inactivated human platelet lysate improves wound healing in diabetic rats. Cytotherapy 2021. [DOI: 10.1016/s1465324921003406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Schmidt T, Schlander D, Jüchter V, Baranyai J, Neuberger F, Schäfer R. Design of a compact and versatile radiation heater with an additively manufactured Nb radiation shield for UHV high-temperature sample preparation. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:025111. [PMID: 33648129 DOI: 10.1063/5.0023982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 01/29/2021] [Indexed: 06/12/2023]
Abstract
A compact, ultrahigh vacuum, radiative heater based on pyrolytic boron nitride that efficiently directs nearly all of its radiation to the sample was designed and constructed. It is shown that the heater reaches temperatures of 1300 K experimentally at 60% of its maximum power. A COMSOL Multiphysics® simulation and an analytical model predict an ultimate temperature of up to 1500 K. Furthermore, the heater does not introduce any contamination to the sample. This is accomplished by a custom-made Nb radiation shield, which was manufactured by selective laser melting and holds a flag-style sample holder. Before manufacturing, the whole assembly was simulated with COMSOL Multiphysics to validate the design of the radiation shield.
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Moreno-Ayala R, Olivares-Chauvet P, Schäfer R, Junker JP. Variability of an Early Developmental Cell Population Underlies Stochastic Laterality Defects. Cell Rep 2021; 34:108606. [PMID: 33440143 PMCID: PMC7809618 DOI: 10.1016/j.celrep.2020.108606] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 10/28/2020] [Accepted: 12/15/2020] [Indexed: 12/11/2022] Open
Abstract
Embryonic development seemingly proceeds with almost perfect precision. However, it is largely unknown how much underlying microscopic variability is compatible with normal development. Here, we quantify embryo-to-embryo variability in vertebrate development by studying cell number variation in the zebrafish endoderm. We notice that the size of a sub-population of the endoderm, the dorsal forerunner cells (DFCs, which later form the left-right organizer), exhibits significantly more embryo-to-embryo variation than the rest of the endoderm. We find that, with incubation of the embryos at elevated temperature, the frequency of left-right laterality defects is increased drastically in embryos with a low number of DFCs. Furthermore, we observe that these fluctuations have a large stochastic component among fish of the same genetic background. Hence, a stochastic variation in early development leads to a remarkably strong macroscopic phenotype. These fluctuations appear to be associated with maternal effects in the specification of the DFCs. High embryo-to-embryo variability of dorsal forerunner cell numbers Fluctuations of dorsal forerunner cells have a large stochastic component Embryos with fewer dorsal forerunner cells frequently develop laterality defects Variability of dorsal forerunner cell numbers is associated to maternal effects
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Lorenz KW, Schäfer R. [TEG-guided treatment of a dabigatran overdose in a patient with acute kidney failure]. Anaesthesist 2020; 69:573-578. [PMID: 32564188 DOI: 10.1007/s00101-020-00801-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 04/30/2020] [Accepted: 05/16/2020] [Indexed: 11/25/2022]
Abstract
This article presents the case of a multimorbid male patient with an accidental dabigatran overdose caused by kidney failure in the context of an acute intestinal disorder. After effective initial antagonizing of the dabigatran effect using idarucizumab a dabigatran rebound was detected caused by a single hemodialysis leading to a severe intrapulmonary hemorrhage. As dabigatran plasma level testing was not available and conventional coagulation analysis was out of interpretable range due to the impact of dabigatran, continuous thrombelastography (TEG) was used to detect the effect of dabigatran and monitor the treatment results. The most significant parameter used in the kaolin activated clotting time was the R‑time parameter, which was massively prolonged by the interrupted coagulation cascade.
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Schäfer R. [RAS mutations at the molecular tumor conference]. DER PATHOLOGE 2019; 40:355-359. [PMID: 31754788 DOI: 10.1007/s00292-019-00702-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Members of the rat sarcoma (RAS) gene family belong to the most frequently mutated genes that drive pathogenesis and therapy response. As the discovery of their malignant potential dates back more than three decades, cellular mutated RAS genes and their products belong to the best characterized cancer genes. Despite urgent clinical needs, RAS therapies are still elusive and limited to preclinical studies. However, very recently, novel and promising approaches have become a reality in clinical applications and trials. In the near future, interesting therapeutic options will emerge that are capable of targeting "undruggable" RAS. This will be even more important as the detection of RAS mutations has already been an integral part of routine molecular diagnostics for many years.
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Janssen G, Pourhassan M, Lenzen-Großimlinghaus R, Jäger M, Schäfer R, Spamer C, Cuvelier I, Volkert D, Wirth R. The Refeeding Syndrome revisited: you can only diagnose what you know. Eur J Clin Nutr 2019; 73:1458-1463. [PMID: 31127188 DOI: 10.1038/s41430-019-0441-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 05/10/2019] [Accepted: 05/13/2019] [Indexed: 02/08/2023]
Abstract
BACKGROUND/OBJECTIVES The Refeeding Syndrome (RFS) is a serious complication in patients receiving nutrition support after a period of severe malnutrition. We frequently recognize and diagnose the RFS due to increased awareness. Thus, we observe that many physicians do not know the RFS and that it is rarely diagnosed. The aim of the study was to determine whether physicians in Germany know the RFS. SUBJECTS/METHODS A questionnaire with a case vignette about an older person who developed the RFS after initiation of nutritional therapy was submitted to German physicians and fifth year medical students, who were participants of educational lectures. RESULTS Of the 281 participants who answered the respective question, 40 participants (14%) correctly diagnosed the RFS of the case vignette and 21 participants (8%) gave nearly correct answers. Indeed, the majority of the participants did not diagnose the RFS. CONCLUSIONS Although the RFS may lead to fatal complications, it is unknown to the majority of the queried physicians. Therefore, there is a call to implement the RFS in respective curricula and increase systematic education on this topic.
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Khong S, Lee M, Khong D, Kosaric N, Duscher D, Dong Y, Schäfer R, Gurtner G. 1407 Single-cell transcriptomics of human mesenchymal stem cells reveal age-related cellular subpopulation depletion and impaired regenerative gene expression. J Invest Dermatol 2018. [DOI: 10.1016/j.jid.2018.03.1425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Schäfer R, Strnad V, Polgár C, Uter W, Hildebrandt G, Ott O, Kauer-Dorner D, Knauerhase H, Major T, Lyczek J, Guinot J, Dunst J, Gutierrez Miguelez C, Slampa P, Allgäuer M, Lössl K, Kovacs G, Fietkau R, Resch A, Kulik A, Arribas L, Niehoff P, Guedea F, Gall C, Polat B. OC-0326: QOL After APBI (Multicatheter Brachytherapy) Versus WBI: 5-Year Results, Phase 3 GEC-ESTRO Trial. Radiother Oncol 2018. [DOI: 10.1016/s0167-8140(18)30636-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Shayeghi A, Pašteka LF, Götz DA, Schwerdtfeger P, Schäfer R. Spin–orbit effects in optical spectra of gold–silver trimers. Phys Chem Chem Phys 2018; 20:9108-9114. [DOI: 10.1039/c8cp00672e] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photodissociation spectra of cationic gold–silver trimers are analysed using relativistic electronic structure theories paying special attention to the importance of spin–orbit and charge transfer effects.
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Strunk D, Lozano M, Marks DC, Loh YS, Gstraunthaler G, Schennach H, Rohde E, Laner-Plamberger S, Öller M, Nystedt J, Lotfi R, Rojewski M, Schrezenmeier H, Bieback K, Schäfer R, Bakchoul T, Waidmann M, Jonsdottir-Buch SM, Montazeri H, Sigurjonsson OE, Iudicone P, Fioravanti D, Pierelli L, Introna M, Capelli C, Falanga A, Takanashi M, Lόpez-Villar O, Burnouf T, Reems JA, Pierce J, Preslar AM, Schallmoser K. International Forum on GMP-grade human platelet lysate for cell propagation: summary. Vox Sang 2017; 113:80-87. [PMID: 29076169 DOI: 10.1111/vox.12593] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Strunk D, Lozano M, Marks DC, Loh YS, Gstraunthaler G, Schennach H, Rohde E, Laner-Plamberger S, Öller M, Nystedt J, Lotfi R, Rojewski M, Schrezenmeier H, Bieback K, Schäfer R, Bakchoul T, Waidmann M, Jonsdottir-Buch SM, Montazeri H, Sigurjonsson OE, Iudicone P, Fioravanti D, Pierelli L, Introna M, Capelli C, Falanga A, Takanashi M, López-Villar O, Burnouf T, Reems JA, Pierce J, Preslar AM, Schallmoser K. International Forum on GMP-grade human platelet lysate for cell propagation. Vox Sang 2017; 113:e1-e25. [PMID: 29071726 DOI: 10.1111/vox.12594] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Soldatov IV, Schäfer R. Selective sensitivity in Kerr microscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:073701. [PMID: 28764508 DOI: 10.1063/1.4991820] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A new technique for contrast separation in wide-field magneto-optical Kerr microscopy is introduced. Utilizing the light from eight light emitting diodes, guided to the microscope by glass fibers and being switched synchronously with the camera exposure, domain images with orthogonal in-plane sensitivity can be displayed simultaneously at real-time, and images with pure in-plane or polar contrast can be obtained. The benefit of this new method of contrast separation is demonstrated for Permalloy films, a NdFeB sinter magnet, and a cobalt crystal. Moreover, the new technique is shown to strongly enhance the sensitivity of Kerr microscopy by eliminating parasitic contrast contributions occurring in conventional setups. A doubling of the in-plane domain contrast and a sensitivity to Kerr rotations as low as 0.6 mdeg is demonstrated.
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Elger B, Schmidt T, Krähling S, Neuberger F, Schäfer R. Electrostatic simulation of a complete cluster deposition apparatus. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:063303. [PMID: 28667987 DOI: 10.1063/1.4984968] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A complete electrostatic model of a cluster deposition apparatus is presented using SIMION. It consists of fifteen different ion optical components including a quadrupole mass filter and a quadrupole ion deflector. The accuracy of the model was tested by comparing calculated cationic cluster transmissions with experimental ion currents by varying the electrostatic potential of different components. Considering the negatively charged particles produced by the magnetron cluster source as a charged background with a density of 5⋅10-7 cm-3, the influence of the first components on cluster transmission is well reproduced in comparison to the experimental results. This background was included by increasing the charge of the clusters from zero to an elementary charge using a sigmoidal function. The inflection point of this function was found to depend on the first components' electrostatic potential but in good approximation, not on later ones. All of the calculated transmissions represent the experimental data quite well; therefore, the simulation is validated and helps us to understand the influence of the electrostatic components on cluster transmission and improve the target efficiency. Furthermore, this understanding opens the possibility for a global optimization scheme to be employed in the ion optics' geometries.
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Redmer T, Walz I, Klinger B, Khouja S, Welte Y, Schäfer R, Regenbrecht C. The role of the cancer stem cell marker CD271 in DNA damage response and drug resistance of melanoma cells. Oncogenesis 2017; 6:e291. [PMID: 28112719 PMCID: PMC5294251 DOI: 10.1038/oncsis.2016.88] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 10/31/2016] [Accepted: 11/25/2016] [Indexed: 12/14/2022] Open
Abstract
Several lines of evidence have suggested that stemness and acquired resistance to targeted inhibitors or chemotherapeutics are mechanistically linked. Here we observed high cell surface and total levels of nerve growth factor receptor/CD271, a marker of melanoma-initiating cells, in sub-populations of chemoresistant cell lines. CD271 expression was increased in drug-sensitive cells but not resistant cells in response to DNA-damaging chemotherapeutics etoposide, fotemustine and cisplatin. Comparative analysis of melanoma cells engineered to stably express CD271 or a targeting short hairpin RNA by expression profiling provided numerous genes regulated in a CD271-dependent manner. In-depth analysis of CD271-responsive genes uncovered the association of CD271 with regulation of DNA repair components. In addition, gene set enrichment analysis revealed enrichment of CD271-responsive genes in drug-resistant cells, among them DNA repair components. Moreover, our comparative screen identified the fibroblast growth factor 13 (FGF13) as a target of CD271, highly expressed in chemoresistant cells. Further we show that levels of CD271 determine drug response. Knock-down of CD271 in fotemustine-resistant cells decreased expression of FGF13 and at least partly restored sensitivity to fotemustine. Together, we demonstrate that expression of CD271 is responsible for genes associated with DNA repair and drug response. Further, we identified 110 CD271-responsive genes predominantly expressed in melanoma metastases, among them were NEK2, TOP2A and RAD51AP1 as potential drivers of melanoma metastasis. In addition, we provide mechanistic insight in the regulation of CD271 in response to drugs. We found that CD271 is potentially regulated by p53 and in turn is needed for a proper p53-dependent response to DNA-damaging drugs. In summary, we provide for the first time insight in a CD271-associated signaling network connecting CD271 with DNA repair, drug response and metastasis.
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Rohr I, Sehouli J, En-Nia A, Heinrich M, Richter R, Chekerov R, Dechend R, Heidecke H, Dragun D, Schäfer R, Gorny X, Lindquist J, Brandt S, Braicu E, Mertens P. Y-box protein-1/p18 as novel serum marker for ovarian cancer diagnosis: A study by the Tumor Bank Ovarian Cancer (TOC). Geburtshilfe Frauenheilkd 2016. [DOI: 10.1055/s-0036-1593015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Kasack K, Schäfer R, Koch H, Küster B. Pan-omic profiling of RAS oncogene-mediated transformation and therapy resistance. Eur J Cancer 2016. [DOI: 10.1016/s0959-8049(16)61620-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Beerling E, Seinstra D, de Wit E, Kester L, van der Velden D, Maynard C, Schäfer R, van Diest P, Voest E, van Oudenaarden A, Vrisekoop N, van Rheenen J. Plasticity between Epithelial and Mesenchymal States Unlinks EMT from Metastasis-Enhancing Stem Cell Capacity. Cell Rep 2016; 14:2281-8. [PMID: 26947068 PMCID: PMC4802222 DOI: 10.1016/j.celrep.2016.02.034] [Citation(s) in RCA: 248] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 12/16/2015] [Accepted: 02/02/2016] [Indexed: 12/20/2022] Open
Abstract
Forced overexpression and/or downregulation of proteins regulating epithelial-to-mesenchymal transition (EMT) has been reported to alter metastasis by changing migration and stem cell capacity of tumor cells. However, these manipulations artificially keep cells in fixed states, while in vivo cells may adapt transient and reversible states. Here, we have tested the existence and role of epithelial-mesenchymal plasticity in metastasis of mammary tumors without artificially modifying EMT regulators. In these tumors, we found by intravital microscopy that the motile tumor cells have undergone EMT, while their epithelial counterparts were not migratory. Moreover, we found that epithelial-mesenchymal plasticity renders any EMT-induced stemness differences, as reported previously, irrelevant for metastatic outgrowth, because mesenchymal cells that arrive at secondary sites convert to the epithelial state within one or two divisions, thereby obtaining the same stem cell potential as their arrived epithelial counterparts. We conclude that epithelial-mesenchymal plasticity supports migration but additionally eliminates stemness-enhanced metastatic outgrowth differences. Direct evidence of EMT obtained in unperturbed breast tumors by real-time visualization EMT exists in breast tumors without experimentally altering EMT inducers Tumor cells that underwent EMT are the migratory cells within a tumor Outgrowth potential differences between states are irrelevant due to plasticity
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Geisen C, Kann G, Strecker T, Wolf T, Schüttfort G, van Kraaij M, MacLennan S, Rummler S, Weinigel C, Eickmann M, Fehling SK, Krähling V, Seidl C, Seifried E, Schmidt M, Schäfer R. Pathogen-reduced Ebola virus convalescent plasma: first steps towards standardization of manufacturing and quality control including assessment of Ebola-specific neutralizing antibodies. Vox Sang 2016; 110:329-35. [PMID: 26766162 DOI: 10.1111/vox.12376] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2015] [Revised: 12/08/2015] [Accepted: 12/09/2015] [Indexed: 01/16/2023]
Abstract
BACKGROUND Ebola virus disease is a public health emergency of international concern, and enormous efforts are being made in the development of vaccines and therapies. Ebola virus convalescent plasma is a promising anti-infective treatment of Ebola virus disease. Therefore, we developed and implemented a pathogen-reduced Ebola virus convalescent plasma concept in accordance with national, European and global regulatory framework. MATERIALS AND METHODS Ebola virus convalescent plasma manufacture and distribution was managed by a collection centre, two medical centres and an expert group from the European Blood Alliance. Ebola virus convalescent plasma was collected twice with an interval of 61 days from a donor recovering from Ebola virus disease in Germany. After pathogen reduction, the plasma was analysed for Ebola virus-specific immunoglobulin G (IgG) antibodies and its Ebola virus neutralizing activity. RESULTS Convalescent plasma could be collected without adverse events. Anti-Ebola virus IgG titres and Ebola-specific neutralizing antibodies in convalescent plasma were only slightly reduced after pathogen reduction treatment with S59 amotosalen/UVA. A patient in Italy with Ebola virus disease was treated with convalescent plasma without apparent adverse effects. DISCUSSION As proof of principle, we describe a concept and practical implementation of pathogen-reduced Ebola virus convalescent plasma manufacture, quality control and its clinical application to an Ebola virus disease patient.
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