156 research outputs found

    Comparison of spheroids formed by rat glioma stem cells and neural stem cells reveals differences in glucose metabolism and promising therapeutic applications

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    Cancer stem cells (CSCs) are thought to be partially responsible for cancer resistance to current therapies and tumor recurrence. Dichloroacetate (DCA), a compound capable of shifting metabolism from glycolysis to glucose oxidation, via an inhibition of pyruvate dehydrogenase kinase was used. We show that DCA is able to shift the pyruvate metabolism in rat glioma CSCs but has no effect in rat neural stem cells. DCA forces CSCs into oxidative phosphorylation but does not trigger the production of reactive oxygen species and consecutive anti-cancer apoptosis. However, DCA, associated with etoposide or irradiation, induced a Bax-dependent apoptosis in CSCs in vitro and decreased their proliferation in vivo. The former phenomenon is related to DCA-induced Foxo3 and p53 expression, resulting in the overexpression of BH3-only proteins (Bad, Noxa, and Puma), which in turn facilitates Bax-dependent apoptosis. Our results demonstrate that a small drug available for clinical studies potentiates the induction of apoptosis in glioma CSCs

    Search for new resonant states in 10C and 11C and their impact on the cosmological lithium problem

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    The observed primordial 7Li abundance in metal-poor halo stars is found to be lower than its Big-Bang nucleosynthesis (BBN) calculated value by a factor of approximately three. Some recent works suggested the possibility that this discrepancy originates from missing resonant reactions which would destroy the 7Be, parent of 7Li. The most promising candidate resonances which were found include a possibly missed 1- or 2- narrow state around 15 MeV in the compound nucleus 10C formed by 7Be+3He and a state close to 7.8 MeV in the compound nucleus 11C formed by 7Be+4He. In this work, we studied the high excitation energy region of 10C and the low excitation energy region in 11C via the reactions 10B(3He,t)10C and 11B(3He,t)11C, respectively, at the incident energy of 35 MeV. Our results for 10C do not support 7Be+3He as a possible solution for the 7Li problem. Concerning 11C results, the data show no new resonances in the excitation energy region of interest and this excludes 7Be+4He reaction channel as an explanation for the 7Li deficit.Comment: Accepted for publication in Phys. Rev. C (Rapid Communication

    Results of screening in early and advanced thoracic malignancies in the EORTC pan-European SPECTAlung platform.

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    Access to a comprehensive molecular alteration screening is patchy in Europe and quality of the molecular analysis varies. SPECTAlung was created in 2015 as a pan-European screening platform for patients with thoracic malignancies. Here we report the results of almost 4 years of prospective molecular screening of patients with thoracic malignancies, in terms of quality of the program and molecular alterations identified. Patients with thoracic malignancies at any stage of disease were recruited in SPECTAlung, from June 2015 to May 2019, in 7 different countries. Molecular tumour boards were organised monthly to discuss patients' molecular and clinical profile and possible biomarker-driven treatments, including clinical trial options. FFPE material was collected and analysed for 576 patients with diagnosis of pleural, lung, or thymic malignancies. Ultimately, 539 patients were eligible (93.6%) and 528 patients were assessable (91.7%). The turn-around time for report generation and molecular tumour board was 214 days (median). Targetable molecular alterations were observed in almost 20% of cases, but treatment adaptation was low (3% of patients). SPECTAlung showed the feasibility of a pan-European screening platform. One fifth of the patients had a targetable molecular alteration. Some operational issues were discovered and adapted to improve efficiency

    Search for resonant states in 10C and 11C and their impact on the primordial 7Li abundance

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    The cosmological 7Li problem arises from the significant discrepancy of about a factor 3 between the predicted primordial 7Li abundance and the observed one. The main process for the production of 7Li during Big-Bang nucleosynthesis is the decay of 7Be. Many key nuclear reactions involved in the production and destruction of 7Be were investigated in attempt to explain the 7Li deficit but none of them led to successful conclusions. However, some authors suggested recently the possibility that the destruction of 7Be by 3He and 4He may reconcile the predictions and observations if missing resonant states in the compound nuclei 10C and 11C exist. Hence, a search of these missing resonant states in 10C and 11C was investigated at the Orsay Tandem-Alto facility through 10B(3He,t)10C and 11B(3He,t)11C charge-exchange reactions respectively. After a short overview of the cosmological 7Li problem from a nuclear physics point of view, a description of the Orsay experiment will be given as well as the obtained results and their impact on the 7Li problem

    Study of the 26Al(n,p)26Mg and 26Al(n,α)23Na reactions using the 27Al(p,p')27Al inelastic scattering reaction

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    26Al was the first cosmic radioactivity ever detected in the galaxy as well as one of the first extinct radioactivity observed in refractory phases of meteorites. Its nucleosynthesis in massive stars is still uncertain mainly due to the lack of nuclear information concerning the 26Al(n,p)26Mg and 26 Al(n,α)23Na reactions. We report on a single and coincidence measurement of the 27Al(p,p')27Al(p)26Mg and 27Al(p,p')27Al(α)23Na reactions performed at the Orsay TANDEM facility aiming at the spectroscopy study of 27Al above the neutron threshold. Fourteen states are observed for the first time within 350 keV above the 26Al+n threshold

    Normal and intruder configurations in Si- 34 populated in the beta(-) decay of Mg-34 and Al-34

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    The structure of Si-34 was studied through gamma spectroscopy separately in the beta(-) decays of Mg-34 and Al-34 at the ISOLDE facility of CERN. Different configurations in Si-34 were populated independently from the two recently identified beta-decaying states in Al-34 having spin-parity assignments J(pi) = 4(-) dominated by the normal configuration pi(d(5/2))(-1) circle times nu(f(7/2)) and J(pi) = 1(+) by the intruder configuration pi(d(5/2))(-1) circle times nu(d(3/2))(-1) (f(7/2))(2). The paper reports on spectroscopic properties of Si-34 such as an extended level scheme, spin and parity assignments based on log(ft) values and gamma-ray branching ratios, absolute beta feeding intensities, and neutron emission probabilities. A total of 11 newly identified levels and 26 transitions were added to the previously known level scheme of Si-34. Large scale shell-model calculations using the SDPF-U-MIX interaction, able to treat higher order intruder configurations, are compared with the new results and conclusions are drawn concerning the predictive power of SDPF-U-MIX, the N = 20 shell gap, the level of mixing between normal and intruder configurations for the 0(1)(+), 0(2)(+), and 2(1)(+) states, and the absence of triaxial deformation in Si-3(4).Peer reviewe

    Defining EGFR amplification status for clinical trial inclusion

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    Background. Precision medicine trials targeting the epidermal growth factor receptor (EGFR) in glioblastoma patients require selection for EGFR-amplified tumors. However, there is currently no gold standard in determining the amplification status of EGFR or variant III (EGFRvIII) expression. Here, we aimed to determine which technique and which cutoffs are suitable to determine EGFR amplification status. Methods. We compared fluorescence in-situ hybridization (FISH) and real-time quantitative (RT-q)PCR data from patients screened for trial inclusion into the Intellance 2 clinical trial, with data from a panel-based next generation sequencing (NGS) platform (both DNA and RNA). Results. By using data from >1000 samples, we show that at least 50% of EGFR amplified nuclei should be present to define EGFR gene amplification by FISH. Gene amplification (as determined by FISH) correlates with EGFR expression levels (as determined by RT-qPCR) with receiver operating characteristics analysis showing an area under the curve of up to 0.902. EGFR expression as assessed by RT-qPCR therefore may function as a surrogate marker for EGFR amplification. Our NGS data show that EGFR copy numbers can strongly vary between tumors, with levels ranging from 2 to more than 100 copies per cell. Levels exceeding 5 gene copies can be used to define EGFR-amplification by NGS; below this level, FISH detects very few (if any) EGFR amplified nuclei and none of the samples express EGFRvIII. Conclusion. Our data from central laboratories and diagnostic sequencing facilities, using material from patients eligible for clinical trial inclusion, help define the optimal cutoff for various techniques to determine EGFR amplification for diagnostic purposes

    Quasi-free (p,2p) reactions in inverse kinematics for studying the fission yield dependence on temperature

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    Despite the recent experimental and theoretical progress in the investigation of the nuclear fission process, a complete description still represents a challenge in nuclear physics because it is a very complex dynamical process, whose description involves the coupling between intrinsic and collective degrees of freedom, as well as different quantum-mechanical phenomena. To improve on the existing data on nuclear fission,we produce fission reactions of heavy nuclei in inverse kinematics by using quasi-free (p,2p) scattering, which induce fission through particle-hole excitations that can range from few to ten\u27s of MeV. The measurement of the four-momenta of the two outgoing protons allows to reconstruct the excitation energy of the fissioning nucleus and therefore to study the evolution of the fission yields with temperature. The realization of this kind of experiment requires a complex experimental setup, providing full isotopic identification of both fission fragments and an accurate measurement of the momenta of the two outgoing protons. This was realized recently at the GSI/FAIR facility and here some preliminary results are presented
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