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International audience; Background: Local recurrences of glioblastoma (GBM) after heavy standard treatments remain frequent and lead to a poor prognostic. Major challenges are the infiltrative part of the tumor tissue which is the ultimate cause of recurrence. The therapeutic arsenal faces the difficulty of eradicating this infiltrating part of the tumor tissue while increasing the targeting of tumor and endogenous stromal cells such as angiogenic endothelial cells. In this aim, neuropilin-1 (NRP-1), a transmembrane receptor mainly overexpressed by endothelial cells of the tumor vascular system and associated with malignancy, proliferation and migration of GBM, highlighted to be a relevant molecular target to promote the anti-vascular effect of photodynamic therapy (VTP).Methods: The multiscale selectivity was investigated for KDKPPR peptide moiety targeting NRP-1 and a porphyrin molecule as photosensitizer (PS), both grafted onto original AGuIX design nanoparticle. AGuIX nanoparticle, currently in Phase II clinical trials for the treatment of brain metastases with radiotherapy, allows to achieve a real-time magnetic resonance imaging (MRI) and an accumulation in the tumor area by EPR (enhanced permeability and retention) effect. Using surface-plasmon resonance (SPR), we evaluated the affinities of KDKPPR and scramble free peptides, and also peptides-conjugated AGuIX nanoparticles to recombinant rat and human NRP-1 proteins. For in vivo selectivity, we used a cranial window model and parametric maps obtained from T2*-weighted perfusion MRI analysis.Results: The photophysical characteristics of the PS and KDKPPR molecular affinity for recombinant human NRP-1 proteins were maintained after the functionalization of AGuIX nanoparticle with a dissociation constant of 4.7 μM determined by SPR assays. Cranial window model and parametric maps, both revealed a prolonged retention in the vascular system of human xenotransplanted GBM. Thanks to the fluorescence of porphyrin by non-invasive imaging and the concentration of gadolinium evaluated after extraction of organs, we checked the absence of nanoparticle in the brains of tumor-free animals and highlighted elimination by renal excretion and hepatic metabolism.Conclusion: Post-VTP follow-ups demonstrated promising tumor responses with a prolonged delay in tumor growth accompanied by a decrease in tumor metabolism.

National audience

Présentation Poster; International audience; Les agents anti-angiogènes sont largement utilisés dans la thérapie anti-cancéreuse, en association avec la chimiothérapieou la radiothérapie, pour leurs effets vasculaires. Ils sont supposés induire des modifications morphologiqueset fonctionnelles au sein du réseau vasculaire tumoral qui permettraient d’accroitre l’efficacité de ces thérapies grâceà l’amélioration de la distribution de la chimiothérapie au sein de la tumeur et à l’amélioration de l’oxygénation tumorale.Cependant, il reste difficile de trouver la séquence de traitements permettant d’avoir une efficacité thérapeutique optimalecar il n’y a à ce jour aucun consensus dans la littérature définissant quand le réseau vasculaire est amélioré et pendantcombien de temps.Nous avons développé un algorithme de traitement d’images capable d’analyser les structures vasculaires observéessur des images en microscopie optique du réseau vasculaire et nous avons suivi leurs modifications, in vivo, au coursdu temps, à l’aide du modèle de la chambre dorsale. L’algorithme a été appliqué pour suivre l’évolution de paramètresvasculaires (surface vasculaire, embranchements, bourgeons, longueur) en réponse ou non au bevacizumab (anti-VEGF,10 mg/kg/jour) pour déterminer une période de « normalisation » du réseau vasculaires par comparaison à des réseauxvasculaires sains.Les résultats présentés ici démontrent que le choix de la région d’intérêt au sein du réseau vasculaire doit se faire en dehors des régions présentant une hiérarchie artériole-capillaire-veinule afin de pouvoir déterminer la période de « normalisation » vasculaire. L’analyse à l’aide de l’algorithme de traitement d’images a permit de définir que la période de « normalisation » se situait entre 8 et 12 jours de traitement par bevacizumab et a été confirmé par analyses immunohistochimiques et évaluation de la fonctionnalité vasculaire (perméabilité, perfusion).Mots clés : thérapie anti-angiogène, normalisation vasculaire, quantification algorithmique, imagerie intravitale.

International audience

National audience; Glioblastoma is a highly angiogenic type of tumor and glioblastoma patients have a low survival rate in spite of all the therapeutic procedures unleashed (surgical resection, radio- and chemotherapy). According to the literature, anti-angiogenic therapies such as the anti-VEGF bevacizumab (Avastin®), can temporarily induce changes in the tumor vasculature that result in improved tissue oxygenation which is crucial to the success of oxygen-dependent radiation therapy.Combining bevacizumab and radiation therapy seems to be a prospective way to improve patient survival. However, finding the best treatment sequence is not an easy task to achieve and no consensus has yet been established because of the lack of knowledge regarding the time and duration of the increased oxygenation window provided by bevacizumab. Hence it is indispensable to define the morphological and functional effects of bevacizumab on the tumor vascular network that impact on the oxygenation to find the perfect timing for its association with radiation therapy.To achieve this aim, we used the skinfold chamber model on nude mice which allows us to observe the evolution of the vascularization of a glioblastoma tumor fragment for at most 5 to 6 weeks. To analyze the effects of bevacizumab on the vascular network, we combined the use of a mathematical tool created by our research team that characterizes morphologically the tumor blood vessels to an immunohistochemical morphological analysis of the tumor vasculature. To seek bevacizumab’s effects on the ability of the tumor blood vessels to deliver blood charged with nutrients and oxygen to the tumor, we evaluated the vascular permeability and the capacity of the blood vessels to perfuse the tumor tissue throughout treatment.Additionally, we used some of the in vivo data of the tumor vascular network obtained with intravital microscopy to develop a mathematical model of the tumor response to the anti-angiogenic and hope to adapt it to clinically relevant data in order to optimize the treatment schedule [1].[1] J.-B. Tylcz, K. El Alaoui-Lasmaili, E.-H. Djermoune, N. Thomas, B. Faivre, & T. Bastogne, Data-driven modeling and characterization of anti-angiogenic molecule effects on tumoral vascular density, Biomedical Signal Processing & Control, 20, 52-60, 2015

National audience; Glioblastoma is a highly angiogenic type of tumor and glioblastoma patients have a low survival rate in spite of all the therapeutic procedures unleashed (surgical resection, radio- and chemotherapy). According to the literature, anti-angiogenic therapies such as the anti-VEGF bevacizumab, can temporarily induce changes in the tumor vasculature that result in improved tissue oxygenation which is crucial to the success of oxygen-dependent radiation therapy. Combining bevacizumab and radiation therapy seems to be a prospective way to improve patient survival. However, finding the best treatment sequence is not an easy task to achieve and no consensus has yet been established because of the lack of knowledge regarding the time and duration of the increased oxygenation window provided by bevacizumab. Hence it is indispensable to define the morphological and functional effects of bevacizumab on the tumor vascular network that impact on the oxygenation to find the perfect timing for its association with radiation therapy. To provide clinicians with tools to determine the best time to treat with radiation after bevacizumab, our research team is developing mathematical models of the tumor vascularization using in vivo data of the tumor vascular network obtained with non-invasive imaging.Glioblastoma tumor fragments were implanted in skinfold chambers borne by nude mice. The evolution of the vascular network in tumors treated or not with bevacizumab at 10 mg/kg/day was observed using intravital microscopy and analyzed with mathematical algorithms created by our research team to quantify daily the effects of bevacizumab on the vascular network. We showed a significate drop in the vascular density and the apparition of a vascular stabilization in the bevacizumab group that was comforted by immunostaining the blood vessels in formalin-fixed tumors. The vascular density data obtained allowed us to create a prototype behavioral-model of the tumor response that shows a perfect simulation of the experimental data both in the control and treated group (Figure 1). Using our biological data, we present here an original approach to characterize and analyze the anti-angiogenic response with a behavioral-model that will in the future help us predict the therapeutic outcome.

Questa tesi verte sulle figure della creatura artificiale e del suo creatore in due romanzi della scena europea dell’Ottocento: "Frankenstein, or the modern Prometheus" di Mary Shelley (1818) e "Le avventure di Pinocchio: storia di un burattino" di Carlo Collodi (1883). In questo corpus, il lettore è capace di osservare la relazione tra il creatore, cioè Victor Frankenstein o Geppetto, e la sua creatura artificiale, ossia il mostro di Frankenstein o Pinocchio. La nostra prima questione di ricerca prova a determinare il tipo di relazione che condividono e a giudicarla positiva o negativa. La nostra seconda domanda, che costituisce la problematica principale del nostro lavoro, si interroga sull’esistenza di un rapporto tra questa relazione e il comportamento dell’essere artificiale attraverso il romanzo. La nostra ipotesi presuppone l’esistere di una tale correlazione: presumiamo che il creatore, e soprattutto la relazione che intrattiene con la sua creatura, influenzano le azioni di quest’ultima. Abbordiamo la problematica con una metodologia che si basa su diversi campi di studio, tra i quali le scienze cognitive e la psicologia che favoriscono il paragonare la creatura artificiale a bambini che crescono, aiutandoci così a elaborare un modello per spiegare il suo comportamento. Ci basiamo anche per analizzare il nostro corpus sulla semantica e su ricerche critiche che rilevano della disciplina letteraria. Tutti questi concetti teorici legati a un’analisi in profondità dei testi ci permetta di rispondere alle nostre domande iniziali. Rispetto alla prima, mostriamo che mentre Geppetto e Pinocchio godono di una relazione piena d’affezione che si avvicina a quella di un padre con suo figlio, Frankenstein e la sua creatura intrattengono una relazione oltremodo negativa. Le nostre ricerche ci hanno poi rivelato l’evoluzione della creatura rispetto al suo comportamento: Pinocchio che evolve positivamente si oppone alla creatura di Frankenstein le cui azioni diventano sempre più negative. Infine, giudichiamo del ruolo del creatore in quest’evoluzione. Concludiamo che la nostra ipotesi per la seconda questione di ricerca non si prova interamente vera nei due libri: mentre dimostriamo l’influsso negativo che Frankenstein e la sua cattiva relazione con la sua creatura hanno sul comportamento di questa, non possiamo certificare che l’evoluzione positiva del burattino sia dovuta alla presenza di Geppetto. Argomentiamo però che la sua relazione affettuosa e quasi paterna con Pinocchio possiede probabilmente un certo influsso sulle motivazioni di quest’ultimo ad evolvere favorevolmente. This thesis deals with the figures of the artificial creature and its creator in two European novels from the nineteenth century: Mary Shelley’s "Frankenstein, or the modern Prometheus" (1818) and Carlo Collodi’s "Le avventure di Pinocchio: Storia di un burattino" (1883). In this corpus, the reader is able to observe the relationship between the creator, that is, Victor Frankenstein or Geppetto, and the creature, i.e. Frankenstein’s monster or Pinocchio. Our first research question tries to determine the type of relationship that they share and to judge it positive or negative. Our second question, which constitutes the main issue of our paper, investigates the existence of a link between this relationship and the behaviour of the artificial being during the novel. Our hypothesis conjectures the existence of such a correlation: we assume that the creator, and especially the relationship that he shares with his creature, influence the actions of the latter. We broach the argument with a methodology that is based on various fields of study, among which cognitive sciences and psychology. These two fields stimulate the comparison between the artificial creature and children that grow up, helping us to elaborate a model to explain the creature’s behaviour. To consider our corpus, we also base ourselves on semantics and on literary critical research. All these theoretical concepts associated with a thorough analysis of the texts allow us to answer our initial questions. Concerning the first one, we show that while Geppetto and Pinocchio enjoy a relationship full of affection that resembles the one of a father and his child, Frankenstein and his creature share an extremely negative relationship. Our research has then revealed the evolution of the creature with regard to its behaviour: Pinocchio positively evolves while the actions of Frankenstein’s artificial creature become more and more negative. Finally, we evaluate the role of the creator in this evolution. We conclude that our hypothesis for the second question is not proved entirely correct in both novels: while we demonstrate the negative influence that Frankenstein and his bad relationship with his creature have on the behaviour of the latter, we cannot certify that Pinocchio’s positive evolution is due to the presence of Geppetto. We argue however that his affectionate and almost paternal relationship with the puppet have some influence on the motivations of Pinocchio to evolve favourably. Master [120] en langues et lettres modernes, orientation générale, Université catholique de Louvain, 2017

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Présentation Poster; National audience

Présentation Poster. Journées organisées par le Groupe Français des Peptides et Protéines (GFPP) and the Protein and Peptide Science Group

International audience; Purpose: Photodynamic therapy (PDT) is based on the interaction of a photosensitizing (PS) agent, light, and oxygen. Few new PS agents are being developed to the in vivo stage, partly because of the difficulty in finding the right treatment conditions. Response surface methodology, an empirical modeling approach based on data resulting from a set of designed experiments, was suggested as a rational solution with which to select in vivo PDT conditions by using a new peptide-conjugated PS targeting agent, neuropilin-1. Methods and Materials: A Doehlert experimental design was selected to model effects and interactions of the PS dose, fluence, and fluence rate on the growth of U87 human malignant glioma cell xenografts in nude mice, using a fixed drug-light interval. All experimental results were computed by Nemrod-W software and Matlab. Results: Intrinsic diameter growth rate, a tumor growth parameter independent of the initial volume of the tumor, was selected as the response variable and was compared to tumor growth delay and relative tumor volumes. With only 13 experimental conditions tested, an optimal PDT condition was selected (PS agent dose, 2.80 mg/kg; fluence, 120 J/cm2; fluence rate, 85 mW/cm2). Treatment of glioma-bearing mice with the peptide-conjugated PS agent, followed by the optimized PDT condition showed a statistically significant improvement in delaying tumor growth compared with animals who received the PDT with the nonconjugated PS agent. Conclusions: Response surface methodology appears to be a useful experimental approach for rapid testing of different treatment conditions and determination of optimal values of PDT factors for any PS agent

Photodynamic therapy (PDT) is a treatment modality against small localized tumors, based on the combined action of a photosensitizer (PS), light and oxygen. A new method of PDT, the VTP (vascular targeted photodynamic therapy) was studied. The purpose of our strategy is to promote the anti-vascular effect of PDT by targeting the tumor vasculature. We studied the behaviour of the tetraphenylchlorine (TPC) conjugated, via the Ahx spacer, to a VEGF co-receptor (neuropilin-1) specific heptapeptide (ATWLPPR), in vitro and in vivo. A comparative study of TPC versus the conjugated PS, TPC-Ahx-ATWLPPR, allowed us to identify in vitro, using a technique of RNA interference-mediated silencing of NRP-1, a receptor-dependent uptake of the conjugate. In vivo, a preferential accumulation of TPC-Ahx-ATWLPPR in endothelial cells and its anti-vascular effect were demonstrated. A study of stability in vitro and in vivo of the conjugate was conducted. In vivo, the peptide sequence was degraded 4 h after intra-venous injection. Pharmacokinetics and tissue biodistribution studies of TPC-Ahx-ATWLPPR and its main degradation product, TPC-Ahx-A, was performed in bearing nude mice. The degradation process of the peptide is important in the organs of the reticulo-endothelial system, where the accumulation of the conjugate is majority. In order to improve in vivo stability of the targeting-peptide, new peptides were design and tested. The pseudopeptide A[psi] [CH2NH] TWLPPR bound NRP-1, and after coupling with the PS, no degradation is observed in plasma in vivo 4 h after intra-venous injection., La thérapie photodynamique (PDT) est une modalité de traitement des petites tumeurs localisées, reposant sur l?action conjuguée d'un photosensibilisateur (PS), de la lumière et de l'oxygène. Dans le cadre d'un nouveau mode de PDT, la VTP (vascular targeted photodynamic therapy), notre stratégie a consisté à favoriser l?effet anti-vasculaire du traitement par ciblage de la néo-vascularisation tumorale. Pour cela, nous avons étudié in vitro et in vivo un PS de type chlorine (TPC) couplé, via le bras espaceur (Ahx), à un heptapeptide (ATWLPPR) spécifique d?un co-récepteur du VEGF, la neuropiline-1 (NRP-1). Une étude comparative de la TPC versus le PS conjugué (TPC-Ahx-ATWLPPR), a permis de mettre en évidence in vitro, grâce à une technique d'ARN interférence visant à éteindre l'expression de NRP-1, une incorporation cellulaire récepteur-dépendante du conjugué. In vivo, l'accumulation préférentielle de la TPC-Ahx-ATWLPPR au niveau de l'endothélium vasculaire de la tumeur ainsi que son effet anti-vasculaire après PDT ont été mises en évidence. Une étude de stabilité in vitro et in vivo du conjugué a été réalisée. In vivo, la séquence peptidique est dégradée 4 h après injection par voie intra-veineuse. Des études de pharmacocinétique et de biodistribution tissulaire de la TPC-Ahx-ATWLPPR et de son principal produit de dégradation, TPC-Ahx-A ont été réalisées chez la souris nude xénogreffée. La dégradation de la partie peptidique est majoritaire dans les organes du système réticulo-endothélial où l'accumulation du conjugué est la plus importante. Dans le but d'augmenter la stabilité in vivo du peptide adresseur, de nouveaux peptides ont été synthétisés, puis couplés à la TPC et testés. Le pseudopeptide A[psi] [CH2NH]TWLPPR est prometteur car il reste affin vis-à-vis de NRP-1 et après couplage au PS, il ne subit aucune dégradation dans le 8plasma in vivo 4 h après injection par voie intra-veineuse.

Photodynamic therapy (PDT) is a treatment modality against small localized tumors, based on the combined action of a photosensitizer (PS), light and oxygen. A new method of PDT, the VTP (vascular targeted photodynamic therapy) was studied. The purpose of our strategy is to promote the anti-vascular effect of PDT by targeting the tumor vasculature. We studied the behaviour of the tetraphenylchlorine (TPC) conjugated, via the Ahx spacer, to a VEGF co-receptor (neuropilin-1) specific heptapeptide (ATWLPPR), in vitro and in vivo. A comparative study of TPC versus the conjugated PS, TPC-Ahx-ATWLPPR, allowed us to identify in vitro, using a technique of RNA interference-mediated silencing of NRP-1, a receptordependent uptake of the conjugate. In vivo, a preferential accumulation of TPC-Ahx-ATWLPPR in endothelial cells and its anti-vascular effect were demonstrated. A study of stability in vitro and in vivo of the conjugate was conducted. In vivo, the peptide sequence was degraded 4 h after intra-venous injection. Pharmacokinetics and tissue biodistribution studies of TPC-Ahx ATWLPPR and its main degradation product, TPC-Ahx-A, was performed in bearing nude mice. The degradation process of the peptide is important in the organs of the reticuloendothelial system, where the accumulation of the conjugate is majority. In order to improve in vivo stability of the targeting-peptide, new peptides were design and tested. The pseudopeptide Aψ[CH2NH] TWLPPR bound NRP-1, and after coupling with the PS, no degradation is observed in plasma in vivo 4 h after intra-venous injection., La thérapie photodynamique (PDT) est une modalité de traitement des petites tumeurs localisées, reposant sur l'action conjuguée d'un photosensibilisateur (PS), de la lumière et de l'oxygène. Dans le cadre d'un nouveau mode de PDT, la VTP (vascular targeted photodynamic therapy), notre stratégie a consisté à favoriser l'effet anti-vasculaire du traitement par ciblage de la néo-vascularisation tumorale. Pour cela, nous avons étudié in vitro et in vivo un PS de type chlorine (TPC) couplé, via le bras espaceur (Ahx), à un heptapeptide (ATWLPPR) spécifique d'un corécepteur du VEGF, la neuropiline-1 (NRP-1). Une étude comparative de la TPC versus le PS conjugué (TPC-Ahx-ATWLPPR), a permis de mettre en évidence in vitro, grâce à une technique d'ARN interférence visant à éteindre l'expression de NRP-1, une incorporation cellulaire récepteur dépendante du conjugué. In vivo, l'accumulation préférentielle de la TPC-Ahx-ATWLPPR au niveau de l'endothélium vasculaire de la tumeur ainsi que son effet anti-vasculaire après PDT ont été mises en évidence. Une étude de stabilité in vitro et in vivo du conjugué a été réalisée. In vivo, la séquence peptidique est dégradée 4 h après injection par voie intra-veineuse. Des études de pharmacocinétique et de biodistribution tissulaire de la TPC-Ahx-ATWLPPR et de son principal produit de dégradation, TPC-Ahx-A ont été réalisées chez la souris nude xénogreffée. La dégradation de la partie peptidique est majoritaire dans les organes du système réticulo-endothélial où l'accumulation du conjugué est la plus importante. Dans le but d'augmenter la stabilité in vivo du peptide adresseur, de nouveaux peptides ont été synthétisés, puis couplés à la TPC et testés. Le pseudopeptide Aψ[CH2NH]TWLPPR est prometteur car il reste affin vis-à-vis de NRP-1 et après couplage au PS, il ne subit aucune dégradation dans le 8plasma in vivo 4 h après injection par voie intra-veineuse.

Since angiogenic endothelial cells of the tumor vasculature represent an interesting target to potentiate the vascular effect of photodynamic therapy, we recently described the conjugation of a photosensitizer (5-(4-carboxyphenyl)-10,15,20-triphenylchlorin,TPC), via a spacer (6-aminohexanoic acid, Ahx), to a VEGF receptor-specific heptapeptide (ATWLPPR), and demonstrated that TPC-Ahx-ATWLPPR binds to neuropilin-1. TPC-Ahx-ATWLPPR was stable in vitro in human and mouse plasma for at least 24 h at 37 ◦C but, following intravenous injection in glioma-bearing nude mice, was degraded in vivo to various rates, depending on the organ considered. TPC-Ahx-A was identified as the main metabolic product and pharmacokinetic studies suggested that its appearance in plasma mainly resulted from the degradation of the peptidic moiety into organs of the reticuloendothelial system. According to in vitro cell culture experiments, TPC-Ahx-ATWLPPR was also significantly degraded after incorporation in human umbilical vein endothelial cells. As we demonstrated that TPC-Ahx-ATWLPPR mostly localized into lysosomes, HUVEC were treated with the lysosomal enzymes inhibitor ammonium chloride, which resulted in a significant decrease of the peptide degradation. But, taken together, our results suggest that the low levels of degradation observed in plasma, tumor and skin, are not likely to have a negative impact on our tumor-targeting photosensitizer strategy.

La thérapie photodynamique (PDT) est une méthode proposée pour le traitement de certains cancers. Cette thérapie est basée sur une activation par la lumière de médicaments dits photo?activables appelés photosensibilisateurs. Les cellules endothéliales tumorales angiogéniques sont des cibles intéressantes pour promouvoir l'effet anti-vasculaire de la PDT. Nous avons récemment décrit (Schneider et al., 2006 ; Tirand et al., 2006) le couplage d'un photosensibilisateur de type chlorine (chlorine 5-(4-carboxyphényl)-10,15,20-triphényl, TPC), via un bras espaceur (6-acide aminohexanoïque, Ahx), à un heptapeptide (ATWLPPR), ciblant neuropiline-1 (NRP-1), un co-récepteur du VEGF (Vascular Endothelial Growth Factor) surexprimé dans les cellules endothéliales angiogéniques. TPC-Ahx-ATWLPPR s'est révélé stable dans du plasma in vitro à 37°C pendant 48h. In vivo, une dégradation peptidique apparaît progressivement dès 2h p.i. aboutissant principalement à la formation du composé TPC-Ahx-A (Tirand et al., 2007). Ce produit de dégradation a été mis en évidence majoritairement dans les organes du système réticulo-endothélial. Afin de stabiliser l'heptapeptide vis-à-vis des peptidases tissulaires (Adessi and Soto, 2002) et d'éviter toute accumulation non sélective du produit de dégradation, ce photosensibilisateur a été couplé à des pseudopeptides (aTWLPPR, rpplwta et Ay[CH2NH]TWLPPR) sur support solide. Nous avons, dans un premier temps, étudié l'affinité de ces pseudopeptides vis-à-vis des différents récepteurs au VEGF165 (NRP-1, NRP-2, Flt-1 et KDR) par compétition en utilisant du VEGF165 biotinylé. Les concentrations efficaces en peptides pour lesquelles la fixation du VEGF165 a été déplacée de 50 % (EC50) ont été comparées. Les récepteurs NRP-1 et NRP-2 sont reconnus par aTWLPPR (EC50=13µM et 7,6 µM) et Ay[CH2NH]TWLPPR (EC50=22µM et 8,9 µM) sans modification d'affinité par comparaison à ATWLPPR (EC50=13,2µM et 7,4 µM) alors que le peptide rétro-inverso n'est pas affin vis-à-vis de ces récepteurs. Ces peptides seront ensuite couplés à la TPC afin d'évaluer leur affinité après couplage à la molécule photoactivable et surtout, leur stabilité in vivo.

International audience

Due to their very poor prognosis and a fatal outcome, secondary brain tumors are one of the biggest challenges in oncology today. From the point of view of the early diagnosis of these brain micro- and macro-tumors, the sensitivity and specificity of the diagnostic tools constitute an obstacle. Molecular imaging, such as Positron Emission Tomography (PET), is a promising technique but remains limited in the search for cerebral localizations, given the commercially available radiotracers. Indeed, the [18F]FDG PET remains constrained by the physiological fixation of the cerebral cortex, which hinders the visualization of cerebral metastases. Tumor angiogenesis is recognized as a crucial phenomenon in the progression of malignant tumors and is correlated with overexpression of the neuropilin-1 (NRP-1) receptor. Here, we describe the synthesis and the photophysical properties of the new gallium-68 radiolabeled peptide to target NRP-1. The KDKPPR peptide was coupled with gallium-68 anchored into a bifunctional NODAGA chelating agent, as well as Cy5 for fluorescence detection. The Cy5 absorbance spectra did not change, whereas the molar extinction coefficient (ε) decreased drastically. An enhancement of the fluorescence quantum yield (φF) could be observed due to the better water solubility of Cy5. [68Ga]Ga-NODAGA-K(Cy5)DKPPR was radiosynthesized efficiently, presented hydrophilic properties (log D = −1.86), and had high in vitro stability (>120 min). The molecular affinity and the cytotoxicity of this new chelated radiotracer were evaluated in vitro on endothelial cells (HUVEC) and MDA-MB-231 cancer cells (hormone-independent and triple-negative line) and in vivo on a brain model of metastasis in a nude rat using the MDA-MB-231 cell line. No in vitro toxicity has been observed. The in vivo preliminary experiments showed promising results, with a high contrast between the healthy brain and metastatic foci for [68Ga]Ga-NODAGA-K(Cy5)DKPPR.

International audience; Nanoparticles based on gold and gadolinium chelates (Au@DTDTPA(Gd)), developed at the UTINAM Institute (CNRS - UMR 6213), have been studied for theranostic purposes in the management of brain tumors, such as aiding MRI imaging and amplifying the micro-dose deposits delivered in radiotherapy. These nanoparticles have also been shown to be particularly interesting in reducing the ability of glial tumor cells to invade the extracellular matrix. Despite the absence of direct cytotoxicity and effect on the proteolytic abilities of glioma cells, gold and gadolinium nanoparticles affected the abilities of glioma cells to migrate individually and collectively. In addition, morphological studies of glioma cells exposed to nanoparticles revealed changes in the architecture of the actin cytoskeleton and a decrease in the number of protrusions required for cell movement. These alterations by gold and gadolinium nanoparticles are associated with a disruption of the biomechanical capacities of glioma cells with an increase in cell stiffness and traction forces at the level of protrusions. Considering the major role of invasive capacities of cancer cells in tumor recurrence and therapeutic failures, these results provide an additional argument on the interest of using gold nanoparticles in cancerology. Supported by the Cancéropôle Est and financed by the Grand Est and Bourgogne-Franche-Comté regions, the realization of this work was possible thanks to (i) the close collaboration between 6 laboratories combining their fields of expertise and know-how in chemistry, cell and animal biology, imaging and digital sciences and (ii) the privileged access to the technological platforms of the Interregion Est.

International audience; AGuIX® 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.