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

AGuIX® from bench to bedside-Transfer of an ultrasmall theranostic gadolinium-based nanoparticle to clinical medicine

International audienceAGuIX® are sub-5 nm nanoparticles made of a polysiloxane matrix and gadolinium chelates. This nanoparticle has been recently accepted in clinical trials in association with radiotherapy. This review will summarize the principal preclinical results that have led to first in man administration. No evidence of toxicity has been observed during regulatory toxicity tests on two animal species (rodents and monkeys). Biodistributions on different animal models have shown passive uptake in tumours due to enhanced permeability and retention effect combined with renal elimination of the nanoparticles after intravenous administration. High radiosensitizing effect has been observed with different types of irradiations in vitro and in vivo on a large number of cancer types (brain, lung, melanoma, head and neck…). The review concludes with the second generation of AGuIX nanoparticles and the first preliminary results on human

Novel generation of ultrasmall high Z tailored nanoparticles for tumor cell radiosensitization

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Evaluation de l’effet sensibilisant des nanoparticules AGuIX® associées à une irradiation photonique dans un modèle de chondrosarcome

International audienceLes chondrosarcomes (CHS), tumeurs malignes du cartilage chimio- et radio-résistantes, représentent environ 20% des tumeurs osseuses primitives de l’adulte. Les nanoparticules AGuIX® associées à l’irradiation photonique ayant conduit à la radiosensibilisation de plusieurs types de tumeurs radiorésistantes (cancer de la tête et du cou, du col utérin, mélanome …), cette stratégie a été testée dans un modèle de CHS in vitro sur cultures 3D en conditions normoxique et physioxique et in vivo dans des souris avec xenogreffe tumorale de CHS (ANR CHONDRAD). L’effet radiosensibilisant des AGuIX® associées à une irradiation photonique a été analysé sur la lignée HEMC-SS dérivée d’un chondrosarcome extra squelettique myxoïde humain.La microscopie en temps réel (IncuCyte®) a permis de suivre l’évolution des sphéroïdes fluorescents HEMC-SS-mKate2 après irradiation associée ou non aux AGuIX®. La combinaison d’une irradiation unique de 4Gy ou d’une irradiation fractionnée (1Gy x 4 jours consécutifs) avec un traitement par AGuIX® a conduit à une radiosensibilisation que ce soit en condition normoxique ou physioxique (2% O2).Pour soutenir l’application clinique potentielle en radiothérapie, des études in vivo ont été réalisées sur un modèle de souris nude avec des xénogreffes HEMC-SS irradiées par des photons avec une dose unique de 4 Gy après une injection intratumorale d’AGuIX®. Les résultats (croissance tumorale et survie) montrent un effet radiosensibilisant significatif des AGuIX®.L’ensemble de ces résultats apportent la preuve de concept de l’effet radiosensibilisant des AGuIX® dans le chondrosarcome

Biological aspects of chondrosarcoma: Leaps and hurdles

International audienceChondrosarcomas are characterized by their chemo- and radioresistance leading to a therapeutic surgical approach which remains the only available treatment with a 10-year survival between 30% and 80% depending on the grade. Non-surgical treatments are under investigation and rely on an accurate biological understanding of drug resistance mechanisms. Novel targeted therapy which represents a new relevant therapeutic approach will open new treatment options by targeting several pathways responsible for processes of proliferation and invasion. Survival pathways such as PI3K, AKT, mTOR and VEGF have been shown to be involved in proliferation of chondrosarcoma cells and antiapoptotic proteins may also play a relevant role. Other proteins such as p53 or COX2 have been identified as potential new targets. This review provides an insight into the biological substantial treatment challenges of CHS and focuses on improving our understanding of CH biology through an overview of major signaling pathways that could represent targets for new therapeutic approaches

Utilisation de nanoparticules à base de gadolinium pour potentialiser l’efficacité de la radiothérapie dans le traitement des cancers des voies aéro-digestives supérieures

International audienceObjectifs : Les cancers des voies aérodigestives supérieures (VADS) sont des cancers agressifs et récurrents du fait de leur radiorésistance intrinsèque. Plusieurs stratégies visant à radiosensibiliser ces tumeurs sont en voie de développement parmi lesquelles l’utilisation de nanoparticules à élément de masse atomique (Z) élevée comme le gadolinium (GBNs). Outre leurs propriétés physiques, elles possèdent des propriétés très intéressantes telles que leur stabilité, l’absence de toxicité associée, leur élimination par voie rénale ainsi que leur accumulation préférentielle au sein des tumeurs, propriétés qui en font de bons candidats comme agents radiosensibilisants

Gadolinium-based nanoparticles as sensitizing agents to carbon ions in head and neck tumor cells

International audienceHadrontherapy presents the major advantage of improving tumor sterilization while sparing surrounding healthy tissues because of the particular ballistic (Bragg peak) of carbon ions. However, its efficacy is still limited in the most resistant cancers, such as grade III-IV head and neck squamous cell carcinoma (HNSCC), in which the association of carbon ions with gadolinium-based nanoparticles (AGuIX®) could be used as a Trojan horse. We report for the first time the radioenhancing effect of AGuIX® when combined with carbon ion irradiation in human tumor cells. An increase in relative biological effectiveness (1.7) in three HNSCC cell lines (SQ20B, FaDu, and Cal33) was associated with a significant reduction in the radiation dose needed for killing cells. Radiosensitization goes through a higher number of unrepaired DNA double-strand breaks. These results underline the strong potential of AGuIX® in sensitizing aggressive tumors to hadrontherapy and, therefore, improving local control while lowering acute/late toxicity

Impact of hyperthermic intraperitoneal chemotherapy on Hsp27 protein expression in serum of patients with peritoneal carcinomatosis

International audienceDespite the strong rationale for combining cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) in patients with peritoneal carcinomatosis, thermotolerance and chemoresistance might result from heat shock protein overexpression. The aim of the present study was thus to determine whether the heat shock protein 27 (Hsp27), a potential factor in resistance to treatment, could have a higher level in serum from patients under this combined therapy. Patients receiving CRS plus HIPEC for peritoneal carcinomatosis (group 1), patients with cancer or a history of cancer undergoing abdominal surgery (group 2), and patients without malignancies undergoing abdominal surgery (group 3) were included. Hsp27 serum levels were determined before and at different times following CRS and HIPEC using enzyme-linked immunosorbent assay. In group 1 (n = 25), the high Hsp27 levels, observed at the end of surgery compared with before (p < 0.0001), decreased during HIPEC, but remained significantly higher than before surgery (p < 0.0005). In groups 2 (n = 11) and 3 (n = 15), surgery did not significantly increase Hsp27 levels. A targeted molecular strategy, inhibiting Hsp27 expression in tumor tissue, could significantly reduce resistance to the combined CRS plus HIPEC treatment. This approach should be further assessed in a clinical phase I trial

AGuIX radiosensitizing nanoparticles: from molecular events to clinical applications

International audienceAGuIX (Activation and Guidance by Irradiation X) is a non-toxic gadolinium-based nanoparticle (GBN) (due to gadolinium entrapped in DOTA) developed by the Lyon University. It accumulates in the tumor through the enhanced permeability and retention (EPR) effect and clears rapidly through the kidneys due to its small size (sub-5nm). Furthermore, AGuIX demonstrates good performance as a contrast agent for MRI.We performed a proof of concept on head and neck squamous cell carcinoma (HNSCC), metastatic melanoma and chondrosarcoma tumors, known for their low survival rates, demonstrating the radiosensitizing efficacy of the AGuIX nanoparticles in cellular (2D and 3D cultures) and preclinical models. GBNs enter HNSCC cancer cells by passive diffusion and macropinocytosis (Rima et al, 2013), localize in cytoplasm, as free particle or entrapped in lysosomes, in close vicinity to the mitochondria. Gadolinium combined with irradiation can produce a large variety of secondary emissions such as secondary, Auger, and Compton electrons leading to the production of reactive oxygen species (ROS) that trigger an intra‐mitochondrial stress (ROS production, transmembrane potential decrease, mtDNA deletion) and nuclear DNA damage leading to cell death.Relative biological efficiency (RBE) in cancer cells is quite comparable to that observed in response to carbon ions, suggesting the existence of common mechanisms through the amplification of the local dose (Miladi et al. Al., Nanomedicine 2015, Wozny et al., submitted).The efficacy of AGuIX has also been demonstrated in orthotopic xenograft models of HNSCC and metastatic melanoma (Miladi et al., 2015, Kotb et al., Theranostics 2016); the experiments are ongoing for chondrosarcoma.Regulatory toxicity studies were conducted in rats and monkeys and a first clinical study was initiated in patients with multiple brain metastases (clinicaltrial.gov).This presentation will summarize our current results with AGuIX nanoparticles used in radiobiology and imaging as well as their first clinical applications.Supported by LabEx PRIMES (ANR-11-LABX-0063

The Use of Gadolinium-based Nanoparticles to Improve Radiation Therapy Efficacy in HNSCC

International audienceHead and neck squamous cell carcinoma (HNSCC) is an aggressive and recurrent malignancy owing to intrinsic radioresistance and lack of apoptosis induction. Several strategies aiming at radiosensitizing these tumors are currently being developed, one of which relies on the use of high Z elements nanoparticles such as gadolinium. Ultrasmall (5nm) gadolinium-based nanoparticles (GBNs) display properties, including stability, lack of toxicity, renal elimination, preferential accumulation in tumors (EPR effect) which make them a promising radiosensitizing tool. Once delivered to the tumor, GBNs amplify the efficacy of radiotherapy through the generation of secondary electrons leading to the overproduction of reactive oxygen species (ROS)