Iron oxide nanoparticles for the improvement of glioblastoma treatment

Malgré le développement de nouveaux traitements, la survie moyenne des patients atteints de gliomes (tumeurs cérébrales malignes) n’a augmenté que de quelques mois ces 25 dernières années. Ces tumeurs se sont révélées très résistantes à la chimiothérapie, notamment à cause de la Barrière Hémato-Encéphalique (BHE) qui empêche une distribution suffisante de médicaments dans la tumeur. La radiothérapie standard n’offre pas non plus de solution appropriée car la dose requise pour stériliser les cellules tumorales provoque aussi la nécrose du tissu cérébral sain. Une nouvelle approche thérapeutique consiste à utiliser l'interaction entre les rayons X et un composé préalablement internalisé dans la tumeur. Ce composé est un élément de numéro atomique élevé et peut être « photoactivé » : une fois excité par un rayonnement X, il génère des cascades d’électrons secondaires qui déposent leur énergie dans leur proche environnement. Cela conduit à une augmentation locale de la dose reçue par les cellules tumorales. Un des paramètres les plus limitants pour la réussite de cette nouvelle stratégie thérapeutique est la concentration et la répartition des éléments radio-sensibilisants que l’on peut obtenir au sein de la tumeur par rapport à un tissu normal. Pour surmonter cette limitation, les nanoparticules (NPs) font actuellement l’objet de nombreuses études car elles permettent de vectoriser une grande quantité d’éléments lourds dans des cibles cellulaires. Le but de ce projet est d'améliorer la distribution des composés radio-sensibilisants via l’utilisation de cellules immunitaires, les macrophages. Reconnus pour leurs grandes capacités de phagocytose, les macrophages peuvent très efficacement intérioriser des NPs et sont capables de migrer vers les sites tumoraux à travers la barrière hémato encéphalique (BHE). Nous souhaitons développer un système d'administration des NPs de fer utilisant les macrophages : ceux-ci, chargés de NPs in vitro, seront injectés par voie veineuse et migreront dans la tumeur en passant à travers la BHE tels des « Chevaux de Troie ». La tumeur sera ensuite irradiée avec un rayonnement X ajusté à l’énergie optimale grâce au rayonnement synchrotron. Les nanoparticules, qui seront alors réparties en grande quantité spécifiquement dans la tumeur, produiront des électrons très toxiques pour les cellules voisines. Ceci conduira à la destruction de la tumeur tout en épargnant les tissus sains.A novel approach for the treatment of tumors consists in using the interaction between X-rays and a drug which has been beforehand internalized into the tumor. This cancer therapy is based on the photo-activation of high atomic number elements, leading to a local dose enhancement delivered to the tumor cells by radiations. This dose enhancement is arising from secondary and Auger electrons created after photoelectric interactions. One of the most limiting parameters for the success of this new therapeutic strategy is the amount and distribution of the radiosensitizer within the tumor versus normal tissue. To overcome this limitation, nanoparticles (NPs) are currently under investigation. The limitation factor is then to address sufficient quantities of the NPs to the tumor. The aim of this project is to improve the radiosensitizer distribution using specific features of macrophages. Indeed, macrophages can very efficiently internalize NPs. In addition, they have been shown to home in on malignant tissues after irradiation (up to ~ 50% of the cells observed in brain tumors are monocytes/macrophages). Thus we will use NPs loaded macrophages as vectors to deliver high amounts of NPs to the tumor. The macrophages will be driven to the tumor bed using microbeam irradiations. The local accumulation of iron-loaded macrophages will increase radiation dose within the tumor upon irradiation with low energy radiations. We expect that this biologically mediated method delivery will overcome the problems of specificity and inhomogeneous distribution of the NPs in the tumor, leading to a significant improvement in the therapeutic efficacy of this innovative treatment

Nanoparticules d'oxyde de fer pour l'amélioration du traitement du glioblastome : étude de leur efficacité sous irradiation synchrotron et optimisation de leur mode d'administration

A novel approach for the treatment of tumors consists in using the interaction between X-rays and a drug which has been beforehand internalized into the tumor. This cancer therapy is based on the photo-activation of high atomic number elements, leading to a local dose enhancement delivered to the tumor cells by radiations. This dose enhancement is arising from secondary and Auger electrons created after photoelectric interactions. One of the most limiting parameters for the success of this new therapeutic strategy is the amount and distribution of the radiosensitizer within the tumor versus normal tissue. To overcome this limitation, nanoparticles (NPs) are currently under investigation. The limitation factor is then to address sufficient quantities of the NPs to the tumor. The aim of this project is to improve the radiosensitizer distribution using specific features of macrophages. Indeed, macrophages can very efficiently internalize NPs. In addition, they have been shown to home in on malignant tissues after irradiation (up to ~ 50% of the cells observed in brain tumors are monocytes/macrophages). Thus we will use NPs loaded macrophages as vectors to deliver high amounts of NPs to the tumor. The macrophages will be driven to the tumor bed using microbeam irradiations. The local accumulation of iron-loaded macrophages will increase radiation dose within the tumor upon irradiation with low energy radiations. We expect that this biologically mediated method delivery will overcome the problems of specificity and inhomogeneous distribution of the NPs in the tumor, leading to a significant improvement in the therapeutic efficacy of this innovative treatment.Malgré le développement de nouveaux traitements, la survie moyenne des patients atteints de gliomes (tumeurs cérébrales malignes) n’a augmenté que de quelques mois ces 25 dernières années. Ces tumeurs se sont révélées très résistantes à la chimiothérapie, notamment à cause de la Barrière Hémato-Encéphalique (BHE) qui empêche une distribution suffisante de médicaments dans la tumeur. La radiothérapie standard n’offre pas non plus de solution appropriée car la dose requise pour stériliser les cellules tumorales provoque aussi la nécrose du tissu cérébral sain. Une nouvelle approche thérapeutique consiste à utiliser l'interaction entre les rayons X et un composé préalablement internalisé dans la tumeur. Ce composé est un élément de numéro atomique élevé et peut être « photoactivé » : une fois excité par un rayonnement X, il génère des cascades d’électrons secondaires qui déposent leur énergie dans leur proche environnement. Cela conduit à une augmentation locale de la dose reçue par les cellules tumorales. Un des paramètres les plus limitants pour la réussite de cette nouvelle stratégie thérapeutique est la concentration et la répartition des éléments radio-sensibilisants que l’on peut obtenir au sein de la tumeur par rapport à un tissu normal. Pour surmonter cette limitation, les nanoparticules (NPs) font actuellement l’objet de nombreuses études car elles permettent de vectoriser une grande quantité d’éléments lourds dans des cibles cellulaires. Le but de ce projet est d'améliorer la distribution des composés radio-sensibilisants via l’utilisation de cellules immunitaires, les macrophages. Reconnus pour leurs grandes capacités de phagocytose, les macrophages peuvent très efficacement intérioriser des NPs et sont capables de migrer vers les sites tumoraux à travers la barrière hémato encéphalique (BHE). Nous souhaitons développer un système d'administration des NPs de fer utilisant les macrophages : ceux-ci, chargés de NPs in vitro, seront injectés par voie veineuse et migreront dans la tumeur en passant à travers la BHE tels des « Chevaux de Troie ». La tumeur sera ensuite irradiée avec un rayonnement X ajusté à l’énergie optimale grâce au rayonnement synchrotron. Les nanoparticules, qui seront alors réparties en grande quantité spécifiquement dans la tumeur, produiront des électrons très toxiques pour les cellules voisines. Ceci conduira à la destruction de la tumeur tout en épargnant les tissus sains

Internalization of Iron Nanoparticles by Macrophages for the Improvement of Glioma Treatment

National audienceRationale: An alternative approach for the improvement of radiotherapy consists in increasing differentially the radiation dose between tumors and normal tissues using nanoparticles (NPs) that have been beforehand internalized into the tumor. These high-Z NPs can be photo-activated by monochromatic synchrotron X-rays, leading to a local dose enhancement delivered to the neighboring tumor cells. In order to carry the NPs into the tumor center, macrophages are currently under study for their phagocytosis and diapedesis abilities. In this study, we characterized J774A.1 macrophages’ internalization kinetics and subcellular distribution of two types of iron NPs.Materials and Methods: Three aspects of internalization were examined: first, the location of internalized NPs in J774A.1 macrophages following a 24h incubation with iron NPs was determined by optical microscopy after cell slicing. Subsequently, the iron intake after a 24h incubation with NPs was characterized using ICP-MS. The resulting cell viability was measured by Trypan Blue staining. Finally, the internalization dynamics were studied by absorbance measurements for 24 hours using a plate reader.Results: J774A.1 macrophages are able to endocytose NPs: we measured ~61±10 pg of internalized iron per macrophage (initial iron concentration: 0.3 mg/mL in culture medium. The cell survival was higher than 80% for all tested conditions (initial iron concentrations in culture medium between 0 and 2.4 mg/mL). Finally, we determined that the internalization kinetics for J774A.1 had a typical saturation time of one hour. These results are currently used in Monte Carlo simulations to model photoactivation processes.Conclusion: Macrophages seem to be promising vectors for NPs, being able to endocytose and retain them in their cytoplasm. Our following studies will attempt to shed light on their other potential abilities as “Trojan Horses”

Internalization of Iron Nanoparticles by Macrophages for the Improvement of Glioma Treatment

National audienceRationale: An alternative approach for the improvement of radiotherapy consists in increasing differentially the radiation dose between tumors and normal tissues using nanoparticles (NPs) that have been beforehand internalized into the tumor. These high-Z NPs can be photo-activated by monochromatic synchrotron X-rays, leading to a local dose enhancement delivered to the neighboring tumor cells. In order to carry the NPs into the tumor center, macrophages are currently under study for their phagocytosis and diapedesis abilities. In this study, we characterized J774A.1 macrophages’ internalization kinetics and subcellular distribution of two types of iron NPs.Materials and Methods: Three aspects of internalization were examined: first, the location of internalized NPs in J774A.1 macrophages following a 24h incubation with iron NPs was determined by optical microscopy after cell slicing. Subsequently, the iron intake after a 24h incubation with NPs was characterized using ICP-MS. The resulting cell viability was measured by Trypan Blue staining. Finally, the internalization dynamics were studied by absorbance measurements for 24 hours using a plate reader.Results: J774A.1 macrophages are able to endocytose NPs: we measured ~61±10 pg of internalized iron per macrophage (initial iron concentration: 0.3 mg/mL in culture medium. The cell survival was higher than 80% for all tested conditions (initial iron concentrations in culture medium between 0 and 2.4 mg/mL). Finally, we determined that the internalization kinetics for J774A.1 had a typical saturation time of one hour. These results are currently used in Monte Carlo simulations to model photoactivation processes.Conclusion: Macrophages seem to be promising vectors for NPs, being able to endocytose and retain them in their cytoplasm. Our following studies will attempt to shed light on their other potential abilities as “Trojan Horses”

Photoactivation of iron nanoparticles for the improvement of glioma treatment

International audienceRationaleAn alternative approach for the improvement of radiotherapy consists in increasing differentially the radiation dose between tumors and normal tissues using nanoparticles (NPs) that have been beforehand internalized into the tumor. These high-Z NPs can be photo-activated by monochromatic synchrotron X-rays, leading to a local dose enhancement delivered to the neighbouring tumor cells. In this study, we evaluated the ability of iron NPs to act as radiosensitizers in vitro and through simulations

Influences of Nanoparticles Characteristics on the Cellular Responses: The Example of Iron Oxide and Macrophages

International audienceIron oxide nanoparticles/microparticles are widely present in a variety of environments, e.g., as a byproduct of steel and iron degradation, as, for example, in railway brakes (e.g., metro station) or in welding fumes. As all particulate material, these metallic nanoparticles are taken up by macrophages, a cell type playing a key role in the innate immune response, including pathogen removal phagocytosis, secretion of free radical species such as nitric oxide or by controlling inflammation via cytokine release. In this paper, we evaluated how macrophages functions were altered by two iron based particles of different size (100 nm and 20 nm). We showed that at high, but subtoxic concentrations (1 mg/mL, large nanoparticles induced stronger perturbations in macrophages functions such as phagocytic capacity (tested with fluorescent latex microspheres) and the ability to respond to bacterial endotoxin lipopolysaccharide stimulus (LPS) in secreting nitric oxide and pro-cytokines (e.g., Interleukin-6 (IL-6) and Tumor Necrosis Factor (TNF)). These stronger effects may correlate with an observed stronger uptake of iron for the larger nanoparticles

Photoactivation of Iron Nanoparticles for the Improvement of Glioma Treatment

International audienceRationale : An alternative approach for the improvement of radiotherapy consists in increasing differentially the radiation dose between tumors and normal tissues using nanoparticles (NPs) that have been beforehand internalized into the tumor. These high-Z NPs can be photo-activated by monochromatic synchrotron X-rays, leading to a local dose enhancement delivered to the neighbouring tumor cells. In this study, we evaluated the ability of iron NPs to act as radiosensitizers in vitro and through simulations.Materials and Methods : The radiosensitizing effect of Fe NPs was assessed through Monte Carlo simulations (PENELOPE) and in vitro experiments: F98 tumor cells were incubated for 24h with Fe NPs before being irradiated at 30 keV, 51 keV or 80 keV. The cell survival was measured by clonogenicity and MTT assays. Subsequently, the iron intake after a 24h incubation with NPs was characterized using ICP-MS and the iron distribution was studied thanks to X-ray fluorescence microscopy.Results : F98 are able to endocytose NPs: we measured ~20±4pg of internalized iron per cell (initial iron concentration: 0.06mg/mL in culture medium). The Fe NPs are located in vacuoles in the cytoplasm. The presence of Fe NPs in the cells caused a 1.6±0.4 enhancement of cell death with 30 keV irradiation (initial iron concentrations in culture medium 0.06 mg/mL).Conclusion : F98 tumor cells were able to endocytose and retain Fe NPs in their cytoplasm, and a significative effect of the NPs was observed for a 30 keV irradiation. Our following studies will attempt to better characterize and optimize the radio-sensitizer properties of Fe NPs and shed light on another way to distribute them into the tumor site.This work was supported by the LabEx PRIMES Lyon, France. We thank ESRF for the beamtime and technical support

Utility of macrophages in an antitumor strategy based on the vectorization of iron oxide nanoparticles

International audienceUtility of macrophages in an antitumor strategy based on the vectorization of iron oxide nanoparticles This Trojan horse strategy aims at specifi cally killing tumor cells. To achieve this goal, High-Z-element nanoparticles brought by macrophages are stimulated using low doses of X-ray radiation. The nanoparticles (namely FERINJECT®) liberate toxic photoelectrons in situ without damaging the surrounding healthy tissues. With its specifi c targeting of cancer cells, this promising anticancer strategy could greatly improve the effi ciency of current radiotherapy. Many solid tumors and their metastases are still resistant to current cancer treatments such as chemo-and radiotherapy. The presence of a small population of Cancer Stem Cells in tumors is held responsible for relapses. Moreover, the various physical barriers of the organism (e.g. blood-brain barrier) prevent many drugs from reaching the target cells. In order to alleviate this constraint, we suggest a Trojan horse strategy consisting of intravascular injection of macrophages loaded with therapeutic nanoparticles (an iron nanoparticle-based solution marketed under the name of FERINJECT®) to bring a high quantity of the latter to the tumor. The aim of this article is to assess the response of primary macrophages to FERINJECT® via functional assays in order to ensure that the macrophages loaded with these nano-particles are still relevant for our strategy. Following this first step, we demonstrate that the loaded macro-phages injected into the bloodstream are able to migrate to the tumor site using small-animal imaging. Finally, using synchrotron radiation, we validate an improvement of the radiotherapeutic effect when FERINJECT®-laden macrophages are deposited at the vicinity of cancer cells and irradiated