Internalization pathways into cancer cells of gadolinium-based radiosensitizing nanoparticles

International audienceOver the last few decades, nanoparticles have been studied in theranostic field with the objective of exhibiting a long circulation time through the body coupled to major accumulation in tumor tissues, rapid elimination, therapeutic potential and contrast properties. In this context, we developed sub-5 nm gadolinium-based nanoparticles that possess in vitro efficient radiosensitizing effects at moderate concentration when incubated with head and neck squamous cell carcinoma cells (SQ20B). Two main cellular internalization mechanisms were evidenced and quantified: passive diffusion and macropinocytosis. Whereas the amount of particles internalized by passive diffusion is not sufficient to inducein vitro a significant radiosensitizing effect, the cellular uptake by macropinocytosis leads to a successful radiotherapy in a limited range of particles incubation concentration. Macropinocytosis processes in two steps: formation of agglomerates at vicinity of the cell followed by their collect via the lamellipodia (i.e. the "arms") of the cell. The first step is strongly dependent on the physicochemical characteristics of the particles, especially their zeta potential that determines the size of the agglomerates and their distance from the cell. These results should permit to control the quantity of particles internalized in the cell cytoplasm, promising ambitious opportunities towards a particle-assisted radiotherapy using lower radiation doses

Comment remplacer l'uranyle dans les contrastes : nouveaux et anciens contrastants

National audienceProblématique : Devant les problèmes rencontrés en terme d’approvisionnement et de traitement des déchets pour l’acétate d’uranyle, la communauté des microscopistes cherche d’autres contrastants susceptibles de donner des résultats similaires. L’objet de ce poster est de donner des pistes, à partir d’essais réalisés dans différents laboratoires sur différents échantillons (cultures de cellules animales, glandes mammaires, racines de plantules), avec différents contrastants, connus ou plus récents. Nous présenterons uniquement des photos d’échantillons osmiés car les contrastes sont meilleurs

Hepatic inflammation elicits production of proinflammatory netrin‐1 through exclusive activation of translation

International audienc