Carbohydrate-based peptidomimetics targeting neuropilin-1: synthesis, molecular docking study and in vitro biological activities

International audienceNeuropilin-1 (NRP-1), a transmembrane glycoprotein acting as a co-receptor of VEGF-A, is expressed by cancer and angiogenic endothelial cells and is involved in the angiogenesis process. Taking advantage of functionalities and stereodiversities of sugar derivatives, the design and the synthesis of carbohydrate based peptidomimetics are here described. One of these compounds (56) demonstrated inhibition of VEGF-A165 binding to NRP-1 (IC50 = 39 μM) and specificity for NRP-1 over VEGF-R2. Biological evaluations were performed on human umbilical vein endothelial cells (HUVECs) through activation of downstream proteins (AKT and ERK phosphorylation), viability/proliferation assays and in vitro measurements of anti-angiogenic abilities

Monte Carlo simulations guided by imaging to predict the in vitro ranking of radiosensitizing nanoparticles

International audienceThis article addresses the in silico–in vitro prediction issue of organometallic nanoparticles (NPs)-based radiosensitization enhancement. The goal was to carry out computational experiments to quickly identify efficient nanostructures and then to preferentially select the most promising ones for the subsequent in vivo studies. To this aim, this interdisciplinary article introduces a new theoretical Monte Carlo computational ranking method and tests it using 3 different organometallic NPs in terms of size and composition. While the ranking predicted in a classical theoretical scenario did not fit the reference results at all, in contrast, we showed for the first time how our accelerated in silico virtual screening method, based on basic in vitro experimental data (which takes into account the NPs cell biodistribution), was able to predict a relevant ranking in accordance with in vitro clonogenic efficiency. This corroborates the pertinence of such a prior ranking method that could speed up the preclinical development of NPs in radiation therapy

Radiosensitizing effect of gold-based nanoparticles for brain tumour treatment

Présentation PosterInternational audienceIntroduction: Metal-based nanoparticles with radiosensitizing aim have promising prospects in the field of radiotherapy. Due to their high X-ray absorption capacity, nanomaterials with high atomic number may indeed improve radiation therapy efficacy in cancer treatment. Clinical trials are ongoing to evaluate the benefit of nanoparticle enhanced radiotherapy. The objective of the present study was to validate the potential of gold nanoparticle enhanced radiotherapy to treat glioblastoma using in silico, in vitro and in vivo approaches.Material and methods: Among a panel of 5 gold nanoparticles (AuNPs), an innovative Monte Carlo simulation approach was used to rank the most promising nanoparticles according to their theoretical radiosensitizing effect. In U87-MG glioblastoma cells, the radiosensitizing effect of the selected nanoobjects was confirmed by clonogenic assays and cell death processes such as apoptosis, senescence, and mitotic catastrophes were investigated. A brain tumour window model, allowing fluorescence-based imaging was used to evaluate the tumour tissue selectivity of Cy5-labelled nanoparticles.Results and discussions: A radiosensitizing effect was determined for 3 among 5 tested AuNPs with a dose modifyingfactor (DMF) from 0.4 to 0.5 (i.e. a DMF equal to 0.5 means the treatment is twice as efficient). Our results showed an inverse relationship between the radiosensitizing effects and the AuNPs sizes. Moreover, the nature of the coating influences the triggered cell death process. In case of PVP-coated AuNPs, the cell death was characterised by a radio-induced senescence in relation with a 1.5-fold increase of the reactive oxygen species production. In contrast, smallest PEG-coated AuNPs triggered post-RX mitotic catastrophes, leading to a delayed cell death. For in vivo experiments, a most promising AuNP (i.e. Au@DTDTPA:Gd) was selected, showing an interesting U87-tumour tissue selectivity.Conclusion: After validating the in vitro radiosensitizing effect of small-sized AuNPs, an innovative design was selected for in vivo experiments. Tumour tissue accumulation and selectivity were evidenced for this innovative nanoparticle. We still have to validate the in vivo radiosensitizing effect using an orthotopic U87 model. We will suggest optimised treatmentmodalities

Stimulation of medulloblastoma stem cells differentiation by a peptidomimetic targeting neuropilin-1

International audienceMedulloblastoma (MB) is the most common malignant pediatric brain tumor. Despite the progress of new treatments, the risk of recurrence, morbidity, and death remains important. The neuropilin-1 (NRP-1) receptor has recently been implicated in tumor progression of MB, which seems to play an important role in the phenotype of cancer stem cells. Targeting this receptor appears as an interesting strategy to promote MB stem cells differentiation. Cancer stem-like cells of 3 MB cell lines (DAOY, D283-Med and D341-Med), classified in the more pejorative molecular subgroups, were obtained by in vitro enrichment. These models were characterized by an increase of NRP-1 and cancer stem cell markers (CD15, CD133 and Sox2), meanwhile a decrease of the differentiated cell marker Neurofilament-M (NF-M) was observed. Our previous work investigated potential innovative peptidomimetics that specifically target NRP-1 and showed that MR438 had a good affinity for NRP-1. This small molecule decreased the self-renewal capacity of MB stem cells for the 3 cell lines and reduced the invasive ability of DAOY and D283 stem cells while NRP-1 expression and cancer stem cell markers decreased at the same time. Possible molecular mechanisms were explored and showed that the activation of PI3K/AKT and MAPK pathways significantly decreased for DAOY cells after treatment. Finally, our results highlighted that targeting NRP-1 with MR438 could be a potential new strategy to differentiate MB stem cells and could limit medulloblastoma progression

Pouvoir radiopotentialisant in vitro de nanoparticules hybrides à base de métaux.

National audienc

Screening process of radiosensitizing nanoparticles based on basic in vitro experimental data and in silico analysis.

Présentation PosterInternational audienc

Radiosensitization with Gadolinium Chelate-Coated Gold Nanoparticles Prevents Aggressiveness and Invasiveness in Glioblastoma

International audienceThis study aimed to evaluate the radiosensitizing potential of Au@DTDTPA(Gd) nanoparticles when combined with conventional external X-ray irradiation (RT) to treat GBM. Methods: Complementary biological models based on U87 spheroids including conventional 3D invasion assay, organotypic brain slice cultures, chronic cranial window model were implemented to investigate the impact of RT treatments (10 Gy single dose; 5×2 Gy or 2×5 Gy) combined with Au@DTDTPA(Gd) nanoparticles on tumor progression. The main tumor mass and its infiltrative area were analyzed. This work focused on the invading cancer cells after irradiation and their viability, aggressiveness, and recurrence potential were assessed using mitotic catastrophe quantification, MMP secretion analysis and neurosphere assays, respectively. Results: In vitro clonogenic assays showed that Au@DTDTPA(Gd) nanoparticles exerted a radiosensitizing effect on U87 cells, and in vivo experiments suggested a benefit of the combined treatment "RT 2×5 Gy + Au@DTDTPA(Gd)" compared to RT alone. Invasion assays revealed that invasion distance tended to increase after irradiation alone, while the combined treatments were able to significantly reduce tumor invasion. Monitoring of U87-GFP tumor progression using organotypic cultures or intracerebral grafts confirmed the antiinvasive effect of Au@DTDTPA(Gd) on irradiated spheroids. Most importantly, the combination of Au@DTDTPA(Gd) with irradiation drastically reduced the number, the viability and the aggressiveness of tumor cells able to escape from U87 spheroids. Notably, the combined treatments significantly reduced the proportion of escaped cells with stem-like features that could cause recurrence. Conclusion: Combining Au@DTDTPA(Gd) nanoparticles and X-ray radiotherapy appears as an attractive therapeutic strategy to decrease number, viability and aggressiveness of tumor cells that escape and can invade the surrounding brain parenchyma. Hence, Au@DTDTPA(Gd)-enhanced radiotherapy opens up interesting perspectives for glioblastoma treatment

Targeting Glioblastoma-Associated Macrophages for Photodynamic Therapy Using AGuIX®-Design Nanoparticles

Glioblastoma (GBM) is the most difficult brain cancer to treat, and photodynamic therapy (PDT) is emerging as a complementary approach to improve tumor eradication. Neuropilin-1 (NRP-1) protein expression plays a critical role in GBM progression and immune response. Moreover, various clinical databases highlight a relationship between NRP-1 and M2 macrophage infiltration. In order to induce a photodynamic effect, multifunctional AGuIX®-design nanoparticles were used in combination with a magnetic resonance imaging (MRI) contrast agent, as well as a porphyrin as the photosensitizer molecule and KDKPPR peptide ligand for targeting the NRP-1 receptor. The main objective of this study was to characterize the impact of macrophage NRP-1 protein expression on the uptake of functionalized AGuIX®-design nanoparticles in vitro and to describe the influence of GBM cell secretome post-PDT on the polarization of macrophages into M1 or M2 phenotypes. By using THP-1 human monocytes, successful polarization into the macrophage phenotypes was argued via specific morphological traits, discriminant nucleocytoplasmic ratio values, and different adhesion abilities based on real-time cell impedance measurements. In addition, macrophage polarization was confirmed via the transcript-level expression of TNFα, CXCL10, CD-80, CD-163, CD-206, and CCL22 markers. In relation to NRP-1 protein over-expression, we demonstrated a three-fold increase in functionalized nanoparticle uptake for the M2 macrophages compared to the M1 phenotype. The secretome of the post-PDT GBM cells led to nearly a three-fold increase in the over-expression of TNFα transcripts, confirming the polarization to the M1 phenotype. The in vivo relationship between post-PDT efficiency and the inflammatory effects points to the extensive involvement of macrophages in the tumor zone.Title in Web of Science: Targeting Glioblastoma-Associated Macrophages for Photodynamic Therapy Using AGuIX((R))-Design Nanoparticles</p

A Coculture Based, 3D Bioprinted Ovarian Tumor Model Combining Cancer Cells and Cancer Associated Fibroblasts

International audienceOvarian cancer remains a major public health issue due to its poor prognosis. To develop more effective therapies, it is crucial to set-up reliable models that closely mimic the complexity of the ovarian tumor's microenvironment. 3D bioprinting is currently a promising approach to build heterogenous and reproducible cancer models with controlled shape and architecture. However, this technology is still poorly investigated to model ovarian tumors. In this study, we describe a 3D bioprinted ovarian tumor model combining cancer cells (SKOV-3) and cancer associated fibroblasts (CAFs). The resulting tumor models showed their ability to maintain cell viability and proliferation. Cells were observed to self-assemble in heterotypic aggregates. Moreover, CAFs were observed to be recruited and to circle cancer cells reproducing an in vivo process taking place in the tumor microenvironment (TME). Interestingly, this approach also showed its ability to rapidly generate a high number of reproducible tumor models that could be subjected to usual characterizations (cell viability and metabolic activity; histology and immunological studies; and real-time imaging). Therefore, these ovarian tumor models can be an interesting tool for high throughput drug screening applications