Etude de la réponse cellulaire à un différentiel de tensions mécaniques (étude spatio-temporelle à l'aide de pinces optiques multiples)

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

Utilisation de nanovecteurs de thérapies gazeuses pour réoxygéner les glioblastomes et augmenter l’efficacité de la radiothérapie

CERVOXYNational audienc

Utilisation de nanovecteurs de thérapies gazeuses pour réoxygéner les glioblastomes et augmenter l’efficacité de la radiothérapie

CERVOXYNational audienc

Nanosized zeolites as a gas delivery platform in a glioblastoma model

CERVOXYInternational audienceApproaches able to counteract, at least temporarily, hypoxia, a well-known factor of resistance to treatment in solid tumors are highly desirable. Herein, we report the use of nanosized zeolite crystals as hyperoxic/hypercapnic gas carriers for glioblastoma. First, the non-toxic profile of nanosized zeolite crystals in living animals (mice, rats and non-human primates) and in various cell types is presented. Second, the ability of the nanosized zeolites to act as a vasoactive agent for a targeted re-oxygenation of the tumor after intravenous injection is shown. As attested by an MRI protocol, the zeolites were able to increase oxygenation and blood volume specifically within the brain tumor whilst no changes in the healthy-non tumoral brain-were observed. The first proof of concept for the use of metal-containing nanosized zeolites as a tool for vectorization of hyperoxic/hypercapnic gases in glioblastoma is revealed

Spatiotemporal Analysis of Cell Response to a Rigidity Gradient: A Quantitative Study Using Multiple Optical Tweezers

We investigate the dynamic response of single cells to weak and local rigidities, applied at controlled adhesion sites. Using multiple latex beads functionalized with fibronectin, and each trapped in its own optical trap, we study the reaction in real time of single 3T3 fibroblast cells to asymmetrical tensions in the tens of pN · μm−1 range. We show that the cell feels a rigidity gradient even at this low range of tension, and over time develops an adapted change in the force exerted on each adhesion site. The rate at which force increases is proportional to trap stiffness. Actomyosin recruitment is regulated in space and time along the rigidity gradient, resulting in a linear relationship between the amount of recruited actin and the force developed independently in trap stiffness. This time-regulated actomyosin behavior sustains a constant and rigidity-independent velocity of beads inside the traps. Our results show that the strengthening of extracellular matrix-cytoskeleton linkages along a rigidity gradient is regulated by controlling adhesion area and actomyosin recruitment, to maintain a constant deformation of the extracellular matrix