New polyvalent low background γ-ray setup at UNamur: Application to S-factor measurements for the 13C(p,γ)14N reaction

The Laboratory of Analysis by Nuclear Reaction (LARN) at the University of Namur (Belgium) is equipped with a low background γ-ray detection system. This setup is made of one ton of lead as passive shielding and plastic scintillators as an anti-cosmic active shielding which covers a large area around a 3.5 × 3.5 inches HPGe detector. This setup makes it possible to reduce the background level from two to three orders of magnitude, depending on the energy range of interest. In this work, this polyvalent detection system is described and used to refine the cross-section measurements of the 13C(p,g)14N nuclear reaction at middle and lowenergies. The reaction 13C(p,g)14N plays an important role in the CNO cycle and s-process in stellar evolution. In this work, we studied more precisely the 13C(p,g)14N ground transition (= 8.06 MeV) for incident energies ranging from 147 to 574.3 keV in the centre-of-mass system generated by the 2 MV Tandetron accelerator ALTAÏS installed at the LARN. Our measurements performed both in reverse (i.e. 1H(13C,g)14N) and direct kinematics are in good agreement with all the data available in the literature, validating our low background detection system.The Laboratory of Analysis by Nuclear Reaction (LARN) at the University of Namur (Belgium) is equipped with a low background γ-ray detection system. This setup is made of one ton of lead as passive shielding and plastic scintillators as anti-cosmic active shielding that covers a large area around a 3.5 × 3.5 in. 2 high purity germanium detector. This setup makes it possible to reduce the background level from two to three orders of magnitude, depending on the energy range of interest. In this work, this polyvalent detection system is described and used to refine the cross-section measurements of the 13C(p,γ) 14N nuclear reaction at middle and low energies. The reaction 13C(p,γ) 14N plays an important role in the carbon-nitrogen-oxygen cycle and s-process in stellar evolution. In this work, we studied more precisely the 13C(p,γ) 14N ground transition (E γ = 8.06 MeV) for incident energies ranging from 147 to 574.3 keV in the center-of-mass system generated by the 2 MV Tandetron accelerator ALTAÏS installed at the LARN. Our measurements performed both in reverse [i.e., 1H( 13C,γ) 14N] and direct kinematics are in good agreement with all the data available in the literature, validating our low background detection system.</p

IGDQ motogenic peptide gradient induces directional cell migration through integrin (αv)β3 activation in MDA-MB-231 metastatic breast cancer cells

In the context of breast cancer metastasis study, we have shown in an in vitro model of cell migration that IGDQ-exposing (IsoLeu-Gly-Asp-Glutamine type I Fibronectin motif) monolayers (SAMs) on gold sustain the adhesion of breast cancer MDA-MB-231 cells by triggering Focal Adhesion Kinase and integrin activation. Such tunable scaffolds are used to mimic the tumor extracellular environment, inducing and controlling cell migration. The observed migratory behavior induced by the IGDQ-bearing peptide gradient along the surface allows to separate cell subpopulations with a “stationary” or “migratory” phenotype. In this work, we knocked down the integrins α5(β1) and (αv)β since they are already known to be implicated in cell migration. To this aim, a whole proteomic analysis was performed in beta 3 integrin (ITGB3) or alpha 5 integrin (ITGA5) knock-down MDA-MB-231 cells, in order to highlight the pathways implied in the integrin-dependent cell migration. Our results showed that i) ITGB3 depletion influenced ITGA5 mRNA expression, ii) ITGB3 and ITGA5 were both necessary for IGDQ-mediated directional single cell migration and iii) integrin (αv)β3 was activated by IGDQ fibronectin type I motif. Finally, the proteomic analysis suggested that co-regulation of recycling transport of ITGB3 by ITGA5 is potentially necessary for directional IGDQ-mediated cell migration

Indacaterol inhibits collective cell migration and IGDQ-mediated single cell migration in metastatic breast cancer MDA-MB-231 cells

Summary: Metastasis is the main cause of deaths related to breast cancer. This is particular the case for triple negative breast cancer. No targeted therapies are reported as efficient until now. The extracellular matrix, in particular the fibronectin type I motif IGDQ, plays a major role in regulating cell migration prior metastasis formation. This motif interacts with specific integrins inducing their activation and the migratory signal transduction.Here, we characterized the migratory phenotype of MDA-MB-231 cells, using functionalized IGDQ-exposing surfaces, and compared it to integrin A5 and integrin B3 knock-down cells. A multiomic analysis was developed that highlighted the splicing factor SRSF6 as a putative master regulator of cell migration and of integrin intracellular trafficking. Indacaterol-induced inhibition of SRSF6 provoked: i) the inhibition of collective and IGDQ-mediated cell migration and ii) ITGA5 sequestration into endosomes and lysosomes. Upon further studies, indacaterol may be a potential therapy to prevent cell migration and reduce metastasis formation in breast cancer. 1CRnmBvVXp9LXQy1nJKbUFVideo Abstrac