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Efficient synthesis of a [18F]F-C-glycosyl dual imaging probe displaying a cyanine for fluorescence imaging (FLI) and a robust [18F]F–C bond for positron emission tomography (PET) imaging.

Considering the individual characteristics of positron emission tomography (PET) and optical imaging (OI) in terms of sensitivity, spatial resolution, and tissue penetration, the development of dual imaging agents for bimodal PET/OI imaging is a growing field. A current major breakthrough in this field is the design of monomolecular agent displaying both a radioisotope for PET and a fluorescent dye for OI. We took advantage of the multifunctionalities allowed by a clickable

Targeting vascular endothelial growth factor receptor (VEFGR) and its co-receptor neuropilin-1 (NRP-1) is an interesting vascular strategy. tLyp-1 is a tumor-homing and penetrating peptide of 7 amino acids (CGNKRTR). It is a truncated form of Lyp-1 (CGNKRTRGC), which is known to target NRP-1 receptor, with high affinity and specificity. It is mediated by endocytosis via C-end rule (CendR) internalization pathway. The aim of this study is to evaluate the importance of each amino acid in the tLyp-1 sequence through alanine-scanning (Ala-scan) technique, during which each of the amino acid in the sequence was systematically replaced by alanine to produce 7 different analogues. In silico approach through molecular docking and molecular dynamics are employed to understand the interaction between the peptide and its analogues with the NRP-1 receptor, followed by in vitro ligand binding assay study. The C-terminal Arg is crucial in the interaction of tLyp-1 with NRP-1 receptor. Substituting this residue dramatically reduces the affinity of this peptide which is clearly seen in this study. Lys-4 is also important in the interaction, which is confirmed via the in vitro study and the MM-PBSA analysis. The finding in this study supports the CendR, in which the presence of R/K-XX-R/K motif is essential in the binding of a ligand with NRP-1 receptor. This presented work will serve as a guide in the future work pertaining the development of active targeting agent towards NRP-1 receptor.

International audience; Monoclonal antibodies targeting tumors are one of the most important discoveries in the field of cancer. Although several effective antibodies have been developed, a relapse may occur. One of their mechanisms of action is Antibody Dependent Cell Cytotoxicity (ADCC), by engaging the Fc γ receptor CD16 expressing Natural Killer cells, innate lymphoid cells involved in cancer immunosurveillance and able to kill tumor cells. A lack of NK cells observed in many cancers may therefore be a cause of the low efficacy of antibodies observed in some clinical situations. Here we review clear evidences of the essential partnership between NK cells and antibodies showed in vitro, in vivo, and in clinical trials in different indications, describe the hurdles and ways to enhance ADCC and the evolution of monoclonal antibody therapy. NK cell adoptive immunotherapy combined with monoclonal antibodies may overcome the resistance to the treatment and enhance their efficacy

International audience; Photodynamic therapy (PDT) is a promising technique to treat different kinds of disease especially cancer. PDT requires three elements: molecular oxygen, a photoactivatable molecule called the photosensitizer (PS), and appropriate light. Under illumination, the PSs generate, in the presence of oxygen, the formation of reactive oxygen species including singlet oxygen, toxic, which then destroys the surrounding tissues. Even if PDT is used with success to treat actinic keratosis or prostate cancer for example, PDT suffers from two major drawbacks: the lack of selectivity of most of the PSs currently used clinically as well as the need for oxygen to be effective. To remedy the lack of selectivity, targeting the tumor neovessels is a promising approach to destroy the vascularization and cause asphyxia of the tumor. KDKPPR peptide affinity for the neuropilin-1 (NRP-1) receptor overexpressed on endothelial cells has already been proven. To compensate for the lack of oxygen, we focused on photoactivatable alkoxyamines (Alks), molecules capable of generating toxic radicals by light activation. In this article, we describe the synthesis of a multifunctional platform combining three units: a PS for an oxygen-dependent PDT, a peptide to target tumor neovessels, and an Alk for an oxygen-independent activity. The synthesis of the compound was successfully carried out, and the study of its photophysical properties showed that the PS retained its capacity to form singlet oxygen and the affinity tests confirmed the affinity of the compound for NRP-1. Thanks to the electron paramagnetic resonance spectroscopy, a technique of choice for radical investigation, the radicals generated by the illumination of the Alk could be detected. The proof of concept was thus successfully established.

The design of bifunctional chelating agents (BFCA) allowing straightforward radiometal labelling of biomolecules is a current challenge. We report herein the development of a bifunctional chelating agent based on a DOTA chelator linked to a

International audience; Glioblastoma multiforme (GBM) is the most aggressive malignant brain tumor. Despite new knowledges on the genetic characteristics, conventional therapy for GBM, tumor resection followed by radiotherapy and chemother-apy using temozolomide is limited in efficacy due to high rate of recurrence. GBM is indeed one of the most complex and difficult cancer to treat mainly due to its highly invasive properties and the standard treatments are thus rarely curative. Major challenges in the treatment of GBM are the limitation of irreversible brain damage, the infiltrative part of the tumor which is the ultimate cause of recurrence, the difficulty of identifying tumor margins and disseminated tumor cells, and the transport across the blood-brain barrier in order to obtain a sufficient therapeutic effect for pharmalogical agents. Considering these limitations, this review explores the in vivo potential of metal-based nanoparticles for hyperthermia, radiotherapy and photodynamic therapy. This article describes and clearly outlines the recent in vivo advances using innovative therapeutic metallic nanoparticles such as iron oxide, silver, gadolinium and gold nanoparticles.

Eloïse Thomas,1 Ludovic Colombeau,2 Mickaël Gries,3,4 Thibaut Peterlini,3,4 Clélia Mathieu,1 Noémie Thomas,3,4 Cédric Boura,3,4 Céline Frochot,2 Régis Vanderesse,5 François Lux,1 Muriel Barberi-Heyob,3,4 Olivier Tillement1 1Université Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique (CNRS), Institut Lumière Matière, Lyon, 2Laboratoire Réactions et Génie des Procédés, Université de Lorraine-CNRS, Nancy, 3Université de Lorraine, Research Center for Automatic Control of Nancy (CRAN), 4CNRS, CRAN, Vandœuvre-lès-Nancy, 5Laboratoire de Chimie Physique Macromoléculaire, Université de Lorraine-CNRS, Nancy, France Abstract: Despite combined treatments, glioblastoma outcome remains poor with frequent local recurrences, indicating that a more efficient and local therapy is needed. In this way, vascular-targeted photodynamic therapy (VTP) could help tumor eradication by destroying its neovessels. In this study, we designed a polysiloxane-based nanoparticle (NP) combining a magnetic resonance imaging (MRI) contrast agent, a photosensitizer (PS) and a new ligand peptide motif (KDKPPR) targeting neuropilin-1 (NRP-1), a receptor overexpressed by angiogenic endothelial cells of the tumor vasculature. This structure achieves the detection of the tumor tissue and its proliferating part by MRI analysis, followed by its treatment by VTP. The photophysical properties of the PS and the peptide affinity for NRP-1 recombinant protein were preserved after the functionalization of NPs. Cellular uptake of NPs by human umbilical vein endothelial cells (HUVEC) was increased twice compared to NPs without the KDKPPR peptide moiety or conjugated with a scramble peptide. NPs induced no cytotoxicity without light exposure but conferred a photocytotoxic effect to cells after photodynamic therapy (PDT). The invivo selectivity, evaluated using a skinfold chamber model in mice, confirms that the functionalized NPs with KDKPPR peptide moiety were localized in the tumor vessel wall. Keywords: nanoparticles, PDT, vascular targeting strategy, brain tumor, NRP-1, peptide ligand, MRI

Medulloblastoma (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 to be an interesting strategy to promote MB stem cells differentiation. Cancer stem-like cells of 3 MB cell lines (DAOY, D283-Med and Med-D341) in different 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 diminution of the differentiated cell marker Neurofilament-M (NF-M) was observed. Our previous work investigated several potential innovative peptidomimetics that specifically targeted 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 phosphorylation of AKT and ERK proteins in PI3K/AKT and MAPK pathways significantly decreased for DAOY-MS cells after treatment. Finally, our results highlighted that targeting NRP-1 with MR438 is a potential new strategy to differentiate MB stem cells and improve chance to cure.

International audience; Photodynamic therapy (PDT) is a cancer treatment modality that requires three components, namely light, dioxygen and a photosensitizing agent. After light excitation, the photosensitizer (PS) in its excited state transfers its energy to oxygen, which leads to photooxidation reactions. In order to improve the selectivity of the treatment, research has focused on the design of PS covalently attached to a tumor-targeting moiety. In this paper, we describe the synthesis and the physico-chemical and photophysical properties of six new peptide-conjugated photosensitizers designed for targeting the neuropilin-1 (NRP-1) receptor. We chose a TPC (5-(4-carboxyphenyl)-10,15, 20-triphenyl chlorine as photosensitizer, coupled via three different spacers (aminohexanoic acid, 1-amino-3,6-dioxaoctanoic acid, and 1-amino-9-aza-3,6,12,15-tetraoxa-10-on-heptadecanoic acid) to two different peptides (DKPPR and TKPRR). The affinity towards the NRP-1 receptor of the conjugated chlorins was evaluated along with in vitro and in vivo stability levels. The tissue concentration of the TPC-conjugates in animal model shows good distribution, especially for the DKPPR conjugates. The novel peptide–PS conjugates proposed in this study were proven to have potential to be further developed as future NRP-1 targeting photodynamic therapy agent.

International audience; Glioma initiating cells (GICs) represent a subpopulation of tumor cells endowed with self-renewal and multilineage differentiation capacity but also with innate resistance to cytotoxic agents, a feature likely to pose major clinical challenges towards the complete eradication of minimal residual disease in glioma patients. In this work, GICs were obtained from two patient-derived high-grade gliomas xenograft model, expressing differently EGFR. GICs were exposed to anti-EGFR monoclonal antibody cetuximab during 48h in 1% or 21% oxygen tension. Cell viability and self-renewal capacity were then evaluated as well as their angiogenic properties. GICs were sensitive to cetuximab only in normoxic condition whatever the EGFR status. Nevertheless, under hypoxia cetuximab was able to decrease the self-renewal capacity as well as the expression of CD133 while expression of GFAP increased. Moreover, cetuximab decreased the effect of GICs on endothelial cell migration under hypoxia. Consequently, anti-EGFR therapy can be envisaged to target specifically GICs in order to limit the tumor recurrence.

Medulloblastoma (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.

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Vascular endothelial growth factor (VEGF) and its co-receptor neuropilin-1 (NRP-1) are important targets of many pro-angiogenic factors. In this study, nine peptides were synthesized and evaluated for their molecular interaction with NRP-1 and compared to our previous peptide ATWLPPR. Docking study showed that the investigated peptides shared the same binding region as shown by tuftsin known to bind selectively to NRP-1. Four pentapeptides (DKPPR, DKPRR, TKPPR and TKPRR) and a hexapeptide CDKPRR demonstrated good inhibitory activity against NRP-1. In contrast, peptides having arginine residue at sites other than the C-terminus exhibited low activity towards NRP-1 and this is confirmed by their inability to displace the VEGF165 binding to NRP-1. Docking study also revealed that replacement of carboxyl to amide group at the C-terminal arginine of the peptide did not affect significantly the binding interaction to NRP-1. However, the molecular affinity study showed that these peptides have marked reduction in the activity against NRP-1. Pentapeptides having C-terminal arginine showed strong interaction and good inhibitory activity with NRP thus may be a good template for anti-angiogenic targeting agent.

International audience; Neuropilin-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.

International audience

Presentation Poster PC-028; International audience

Présentation Poster; International audience

Introduction: Medulloblastoma (MB) is the most common paediatric malignant brain tumour. Recurrences occur in more than 40% of cases and sequelae are very important due to aggressiveness of the treatments. Cancer stem cells (CSCs) generate tumours through the stem cell patterns of self-renewal and differentiation into multiple tumour cell types and have better DNA repair capability inducing tumour resistance to radiotherapy (RT) and chemotherapy. Neuropilin-1 (NRP1) is involved in the progression of MB and seems to be in relation with the differentiation state of cancer cells. Recent molecular research has provided a better understanding of tumour development for the purpose of more targeted treatments. MR438 is a new sugarbased peptidomimetic targeting NRP-1. Our first results showed that MR438 seemed to induce the differentiation of MB stem cells. The objectives were therefore to demonstrate the effect of MR438 on in vitro and in vivo radiosensitivity. Material and methods: DAOY, D283Med and D341Med cell lines were used for obtaining cancer stem cells by in vitro enrichment. Clonogenic assays were performed on MB stem cells exposed to 0, 2, 4, 6, 10 Gy of RT in combination with MR438. For in vivo experiments, xenografted nude mice with 3 subgroup tumours were treated by RT at 2 Gy x 5 days in combination with MR438 and compared to Tuftsin in 6 groups (control, MR438, Tuftsin, RT, RT +MR438, RT +Tuftsin, n=6). Tumour volume was measured by calliper until a maximum of 45 days post-treatment, and then tumours were removed at the set end-points for clonogenic assay and cell viability. Results and discussions: Inhibition of NRP-1 via MR438 increased radiosensitivity of CSC models especially at the dose of 2 Gy. The DMF2 were 0.74, 0.89 and 0.88 for DAOY, D283-Med and Med-D341 cells respectively. In heterotopic models, a significant improvement of tumours radiosensitivity was also observed in the MR438 +RT group by comparing RT alone or MR438 alone (p

Recently, the use of polyelectrolyte films has been suggested as a new versatile technique of surface modification aimed at tissue engineering. In the present study, we evaluated the expression of intercellular adhesion molecule (ICAM)-1 of endothelial cells (ECs) seeded on two types of polyelectrolyte multilayer films either terminated by poly(D-lysine) (PDL) or poly(allylamine hydrochloride) (PAH). This work showed that chemical stimulations with tumor necrosis factor (TNF)-alpha induced the ICAM-1 expression of ECs differently depending largely on the film architecture employed. Compared with PAH-ending films, the PDL-ending ones upregulated the ICAM-1 expression of the ECs after a prolonged exposition to TNF-alpha, rendering this film type less favorable in tissue engineering. Cytochalasin D (an F-actin disrupting agent) showed the involvement of the cytoskeleton in the upregulation of ICAM-1 for cells deposited on films terminated by PDL. The PAH-ending films did not perturb the ICAM-1 expression of ECs and might thus enhance the seeding of ECs in vascular engineering.

International audience; The seeding of endothelial cells (ECs) on biomaterial surfaces became a major challenge, allowing to improve the non-thrombogenic properties of these surfaces. Recently, the use of polyelectrolyte films has been suggested as a new versatile technique of surface modification aimed at tissue engineering. In this study, we evaluate the adhesion properties of ECs on two types of polyelectrolyte films ending either by poly(D-lysine) (PDL), or poly(allylamine hydrochloride) (PAH), and compared them to data obtained on PDL or PAH monolayers, glass and fibronectin (Fn)-coated glass. ECs seeded on polyelectrolyte films showed a good morphology, allowing ECs to resist physiological shear stress better compared to ECs seeded on glass or Fn. The expression of beta1 integrins was slightly lower on polyelectrolyte films than on control surfaces. However, the phosphorylation of focal adhesion kinase, involved in the transduction of adhesion signal, was not modified on PAH ending films compared to control surfaces; whereas it became lower on PDL ending films. Finally, PAH ending films improve strongly ECs adhesion without disturbing the adhesion mechanism, necessary for the development of a new endothelium. These types of films or similar build-ups could thus be used in the future as a way to modify surfaces for vascular tissue engineering.

Endothelial cell seeding constitutes an appreciated method to improve blood compatibility of small-diameter vascular grafts. In this study, we report the development of a simple innovative technique based on multilayered polyelectrolyte films as cell adhesive substrates. Polyelectrolyte multilayered films ending by poly(sodium-4-styrenesulfonate)/poly(allylamine hydrochloride) (PSS/PAH) or poly( l -glutamic acid)/poly( d -lysine) (PGA/PDL) could enhance cell adhesion by modification of the physico-chemical properties of the surface. The biological responses of human umbilical vein endothelial cells seeded on the polyelectrolyte multilayer films, on PDL or PAH monolayers, and on control surfaces, were evaluated in terms of initial attachment, growth, cellular metabolic activity, endothelial phenotype, and adhesion. The results showed that polyelectrolyte multilayers neither induce cytotoxic effects nor alter the phenotype of the endothelial cells. The polyelectrolyte multilayered films enhanced initial cell attachment as compared to the polyelectrolyte monolayer. Cell growth observed on the films was similar to that on TCPS. Among the different coating tested, the film ending by PSS/PAH exhibited an excellent cellular biocompatibility and appeared to be the most interesting surface in terms of cellular adhesion and growth. Such films could be used to cover hydrophobic (cell resistant) substrates in order to promote cell colonization, thereby constituting an excellent material for endothelial cell seeding.

Therapeutic goals for hemorrhagic shock resuscitation are the increase of cardiac output and oxygen delivery. The possibility exists that because of microcirculatory effects, different volume expanders result in different tissue oxygen delivery and oxygen use. In a rabbit model of resuscitation from hemorrhagic shock (50% blood loss), we compared the effects of an hemoglobin-based O2-carrying solution (HbOC) with those elicited by albumin, hydroxyethyl starch (HES), or saline on systemic hemodynamics, skeletal muscle O2 pressure (PtiO2), and interstitial concentration of lactate (LACi) through the combined implantation of a microdialysis probe and a sensitive O2 electrode into the hind limb. Hemorrhagic shock induced a 50% decrease in mean arterial pressure (MAP), femoral artery blood flow (BF), and PtiO2. After resuscitation, there were statistically significant differences among the volume expanders. The increase in MAP was faster with HbOC and colloids, and slower with saline, mainly obtained by vasoconstriction for HbOC and by increased BF with albumin and HES. The maximum MAP values were significantly higher for HbOC compared with the other volume expanders. HbOC and colloids induced a faster increase in PtiO2 as compared with saline, but maximum PtiO2 values were not different among the volume expanders. Tissue oxygen use as estimated by LACi increased transiently at the beginning of volume expansion with similar maximum values. Animals resuscitated with saline had significantly higher LACi concentrations after the onset of volume expansion as compared with HbOC but not with colloids. Our results demonstrate that there are measurable differences in MAP and BF upon resuscitation with the four different solutions and there is a slower increase in tissue PtiO2 with saline than with colloids associated with significantly increased LACi consistent with delayed reoxygenation upon resuscitation with saline.

AIMS: Glioblastoma (GBM) is the most lethal of all human tumors. Ionizing radiation (IR), as a major therapeutic modality, induces multiple types of DNA lesions in cells, therefore causes cell death. However, IR could also affect neighboring unirradiated cells, inducing Bystander Effects as chromosomal aberrations, increased proliferation, etc. Intercellular communication through the release of different components is involved in the mechanism. GBM cells release different soluble factors as well as tumor microvesicles (TMVs) to modify the phenotype of neighboring cells, thus participating in the tumor progression. The present study was designed to investigate in vitro the impact of IR on the communication between tumor cells and endothelial cells in the tumor microenvironment via soluble factors and TMVs. MATERIALS AND METHODS: Two GBM cell lines (T98G, U87) were grown and sham-irradiated (0Gy) or irradiated (2 or 10Gy) using a Clinac iX linear accelerator. Cell culture media (CM) were collected. Filtrate (containing only soluble factors) and TMVs were separated with successive centrifugations and Pierce concentrator. Cell viability was assessed by cell counting using trypan blue. TMVs quantifications were performed by flow cytometry. The effect of CM/Filtrate/TMVs on the global behavior (proliferation, adhesion) of bystander tumor cells or HUVEC was investigated using the xCELLigence system (ACEA). RESULTS: As expected, irradiation caused a loss of cell number in U87 and T98G: 20% at 2Gy and 60% at 10Gy 48h post-IR as compared to untreated cells. Both CM and Filtrate collected from sham-irradiated tumor cells induced a 50% reduction of bystander tumor cells proliferation, while CM and Filtrate recovered from 10Gy-irradiated cells had different influence on the proliferation: herein, the inhibitory properties of CM were less marked than those of Filtrate. The discordant effects between CM and Filtrate led us to investigate the role of TMVs. When quantified using flow cytometry, two-fold more TMVs were found in 10Gy-irradiated T98G as compared to untreated cells 48h post-IR, while in U87 this stimulation of release was observed at 2h. TMVs were shown to induce a 2-fold increase of HUVEC cell index. Interestingly after 10Gy-irradiation, TMVs from both cell lines slightly also favored both bystander tumor cells and HUVEC proliferation. CONCLUSION: IR inhibits GBM cells proliferation. IR stimulates TMVs release by GBM cells in a time- and line-dependent manner. IR facilitates tumor progression by stimulating the proliferation of bystander tumor cells as well as favoring tumor angiogenesis via TMVs.

International audience; Specific phenotypic effects of PTEN in head and neck squamous cell carcinoma (HNSCC) remain poorly defined without a direct causal connection between the loss of PTEN function and the progression of cancer. Here, we describe a potential role for PTEN in cancer progression. Using an shRNA targeting PTEN in HNSCC cells, we show that the loss of PTEN expression is associated with a decrease of cell adhesion, a reduction in E-cadherin expression while cell migration is promoted. Together with the tissue organization and molecular markers expressed in tumors derived from shPTEN cells in vivo, this study indicates that HNSCC cells deficient in PTEN expression undergo an epithelial‑mesenchymal transition (EMT). Additionally, our results suggest that both the low levels of expression and subcellular localization of PTEN are involved in the EMT phenotype, and ultimately in possible locoregional reccurences. We hypothesize that the loss of PTEN expression as well as the subcellular localization could be of interest as a predictive marker of recurrence in HNSCC.

International audience; Antiangiogenic and vascular disrupting agents are in the current cancer therapeutic armamentarium. A better understanding of the intricate mechanisms ruling neovessel survival within tumors during or after treatment is needed. Refinement of imaging and a growing knowledge of molecular biology of tumor vascularization provide new insights. It is necessary to define suitable methods for monitoring tumor response and appropriate tools to analyze data. This review compares most commonly used preclinical models, considering their recent improvements, and describes promising new approaches such as microfluidics, real-time electrical impedance based technique and noninvasive imaging techniques. The advantages and limitations of the in vitro, ex vivo and in vivo models are discussed. This review also provides a critical summary of emerging approaches using mathematical modeling.

Overexpression of EGFR plays a key-role in head and neck squamous cell carcinoma (HNSCC) and justifies the extensive use of cetuximab, a monoclonal anti-EGFR antibody, as well as EGFR-tyrosine kinase inhibitors (EGFR-TKI), which have been reported to inhibit tumor cell growth and the secretion of pro-angiogenic factors by tumor cells, such as VEGF and IL-8. Moreover, vessel normalization in tumors, suggesting a more complex mediation of endothelial cell growth control has also been observed in vivo. The present study was designed to investigate the angiogenic consequences of exposure of HNSCC tumor cell lines to cetuximab and intercellular signaling between tumor and endothelial cells by secretion of pro- and anti-angiogenic mediators in the conditioned media (CM). The results achieved showed that cetuximab decreased the secretion of VEGF by HNSCC cells and that exposure of human umbilical vein endothelial cells (HUVEC) to CM from HNSCC cells exposed to cetuximab induced an increase in endothelial cell network formation. Angiogenesis proteome profiling showed that cetuximab induced a complex alteration of the secretion of pro- and anti-angiogenic factors by HNSCC cells without enabling to identify a unique molecular marker. Expression of endothelial membrane receptors (VEGFR-2, EGFR, PECAM-1 and Notch-4) was investigated and only EGFR expression was found influenced when HUVEC were exposed to CM from cetuximab-exposed HNSCC cells. These results showed that the decrease in the secretion of pro-angiogenic agents like VEGF by HNSCC cells exposed to cetuximab could not be sufficient to justify its anti-angiogenic activity in vitro.

The implication of loss of PTEN expression in resistance to targeted therapy has already been described in many tumor types. The absence of response to anti-EGFR agents in PTEN-deficient tumors relies on persistent activation of signaling pathways downstream of pEGFR. To investigate the role of PTEN loss of expression in head and neck squamous cell carcinoma (HNSCC) response to cetuximab, we used siRNA in Cal 27 cells and then evaluated key signaling protein activation (pAKT and pERK 1/2) as well as cell viability and proliferation. PTEN silencing in Cal 27 cells led to a constitutive activation of signaling pathways evidenced by a strong increase in pAKT and pERK 1/2 expression. Moreover, PTEN-silenced cells did not show any significant changes either in cell viability or proliferation, only slight modifications on cell cycle. Additionally and unpredictably, our results indicated that PTEN silencing, led to a drastic reduction in pEGFR expression whereas total EGFR level did not significantly vary. Strikingly, despite this overactivation of signaling pathways ruling cell survival and proliferation in siPTEN cells, cetuximab fully exerted pAKT and pERK 1/2 inhibition of expression, similarly to its effect in untransfected Cal 27 cells. In conclusion, our study established that in Cal 27 cells, cetuximab keeps full ability to inhibit EGFR-dependent mechanisms, as shown by a decreased pAKT and pERK 1/2 level of expression, despite a strong PTEN silencing-induced overactivation. In Cal 27 cells, loss of PTEN expression does not lead to a loss of cetuximab efficacy in inhibiting EGFR-downstream signaling pathways, contrarily to data shown in previous works conducted in other tumor types.

The use of cryopreserved arteries for vascular tissue engineering provides a promising way for vessel replacement. Unfortunately cryopreservation induces structural changes that strongly modify the mechanical properties and alter the thrombogenicity of the vessel after implantation. We present here a new procedure to treat the inner coating of cryopreserved arteries with poly(sodium-4-styrene sulfonate)/poly(allylamine hydrochloride) polyelectrolyte multilayers. We show that this treatment improves the mechanical properties of the cryopreserved vessel. It also allows the adhesion and spreading of endothelial cells so that the internal structure of the vessel closely resembles that of fresh arteries. Finally, we verify by PECAM-1 and von-Willebrand-factor (vWF) expression that this treatment preserves the phenotype of the endothelial cells. This study should open new routes towards the development of future, new biocompatible tissue substitutes allowing long-term functionality after implantation.

International audience; Although autogenous vessels are useful in surgery, often patients cannot furnish suitable vessels. If there are not available, two possible alternatives for vessel replacements are to use vascular synthetic prostheses such as Dacron((R)) and polytetrafluoroethylene (PTFE) or cryopreserved allografts. However, their success has been limited to replace small-diameter (

International audience; Small-diameter synthetic vascular grafts of expanded poly(tetrafluoroethylene) (ePTFE) polymer concern one of the most common alternatives for the replacement of diseased vessels. However, high failure rates arise especially due to the lack of endothelial cells (ECs). EC seeding was developed to build a monolayer on the luminal surface. Because ECs show little or no adhesion on synthetic prostheses, it is necessary to promote their retention. On ePTFE surfaces we successfully deposited polyelectrolyte multilayer films (PMFs) consisting of poly(ethylenimine) (PEI), poly(sodium 4-styrenesulfonate) (PSS), and poly(allylamine hydrochloride) (PAH) to obtain PEI-(PSS-PAH)3 films. EC adhesion and spreading on modified ePTFE were assessed by scanning electron and confocal microscopies. Cell viability was evaluated by Alamar Blue assay. After 7 days of culture, the ePTFE modified with PMF exhibited improvements of EC viability as compared to that of the controls (nonmodified ePTFE) or even ePTFE coated by a PAH monolayer (p < 0.05). Moreover, the spreading of ECs was largely enhanced compared to that of the same controls, resulting in a healthy confluent cell monolayer formation. Positive staining for the von Willebrand factor confirmed the EC phenotype. Promoting EC attachment and function on ePTFE modified with PMFs could become in the future a promising treatment for synthetic small-diameter vascular grafts.

molecular transport processes on a larger scale, through a fluorescence inhibition method. The system Boxcar EG&G (4100) performs the lifetimmeasurement by scanning the temporal gate along the fluorescence decay. Op tical sections oadhesive molecules (ICAM-1) labelling were obtained with a 3D-scanning microscopy (CSPI-Scanalytic’s, EPR

L'auteur de la thèse a souhaité limiter l'accès aux membres de l'Enseignement supérieur français.; Les transports aériens jouissent d'une popularité grandissante et attirent des passagers de tout ordre. Prendre l'avion expose le patient voyageur à un environnement inhabituel pouvant présenter des répercussions sur sa santé. C'est pourquoi, le pharmacien peut être confronté aux questions suivantes : Est-il judicieux de laisser un patient prendre l'avion ? Quelles précautions peut-il lui conseiller avant ce voyage aérien ? Dans quels cas, doit-il lui déconseiller ce déplacement afin de préserver sa santé ? Le pharmacien devra conseiller et orienter le futur voyageur aérien. Certaines pathologies nécessitent des recommandations particulières, le pharmacien d'officine joue un rôle important en ce sens et peut être fréquemment sollicité dans la pratique de son exercice. Il dispose également d'un large choix de traitements disponibles sans ordonnance, ayant principalement une action préventive.

Texte intégral accessible uniquement aux membres de l'Université de Lorraine jusqu'au 15 janvier 2022; Medulloblastoma (MB) is the most common malignant pediatric brain tumors which is the leading cause of cancer death in children. Despite the progress of new treatments, the risk of recurrence, morbidity, and death after treatment remain important. The neuropilin-1 receptor (NRP-1) has recently been implicated in tumor progression of MBs, which seems to play an important role in the phenotype of cancer stem cells (CSCs). Targeting this molecule could thus present an interesting therapeutic value in the treatment of MB. We have selected cancer stem like cells of MBs in the form of medullospheres (MSs) from 3 cell lines (DAOY, D283-Med and Med-D341). These models were characterized by expression of neuropilins (NRP-1 and NRP-2) and phenotypic markers (CD133, CD15 and NF-M). Results showed a significant increase of the expression of NRP-1 by our CSCs models cultured in MSs that confirms our targeting strategy. The impact of the treatment of these cells with an innovative compound specifically targeting NRP-1, MR438, was then evaluated in vitro alone and in association with radiotherapy, especially on the study of the capacity for self-renewal. A decrease of self-renewal capacity for MB stem cells after exposition of MR438 with an increase of radiosensitivity for the 3 cell models in vitro was demonstrated. In vivo, MR438 was evaluated on heterotopic xenograft models in nude mice and showed a significant augmentation of radiosensitivity for DAOY tumors with a tendency to decrease tumor progression for the other 2 cell lines. Interestingly, the compound MR438 induced a significant decrease in the number of stem cells for all of our models. The compound appeared to induce CSCs to a differentiated phenotype at least for the DAOY cells, although mechanisms could not be clearly elucidated. In conclusion, inhibition of NRP-1 via MR438 seems to stimulate the differentiation of CSCs that may eventually reduce the progression of MB and bring a benefit in association with radiotherapy. Evaluation of this compound on orthotopic models of MB would provide information on its effectiveness on models closer to the physiopathology taking into account its distribution at the cerebral level; Le médulloblastome (MB) est la plus fréquente des tumeurs cérébrales malignes pédiatriques qui représentent la première cause de mortalité par cancer chez l’enfant. Malgré les avancées des nouveaux traitements, les risques de récidive, séquelles et décès après traitement restent importants. Le récepteur de neuropiline-1 (NRP-1) a été récemment impliqué dans la progression tumorale des MBs et semble jouer un rôle important dans le phénotype des cellules souches cancéreuses (CSCs). Le ciblage de cette molécule pourrait ainsi présenter un intérêt thérapeutique dans le traitement des MBs. Nous avons sélectionné des cellules souches de MB capables de former des médullosphères (MS) à partir de 3 lignées cellulaires (DAOY, D283-Med et D341-Med). Ces modèles ont été caractérisés par l’expression de neuropilines (NRP-1 and NRP-2) et de marqueurs phénotypiques (CD133，CD15 et NF-M). Les résultats ont montré une augmentation significative de l’expression de NRP-1 par les cellules cultivées en médullosphères confortant notre stratégie de ciblage. L’impact du traitement de ces cellules par un composé innovant ciblant spécifiquement NRP-1, le MR438, a été ensuite évalué in vitro seul et association avec la radiothérapie notamment sur l’étude de la capacité d’auto-renouvellement des CSCs de MBs. Nous avons mis en évidence une diminution de la capacité d’autorenouvellement des cellules souches de MBs après exposition au MR438 avec une radiosensibilité augmentée pour les 3 modèles cellulaires. In vivo, le composé MR438 a été evalué sur des modèles de xénogreffes hétérotopiques chez la souris nude et montre un effet radiopotentialisant significatif pour les tumeurs issues de la lignée Daoy avec une tendance à la diminution de la progression tumorale pour les 2 autres lignées. De façon intéressante, le composé MR438 induit une diminution significative du nombre de cellules souches pour l’ensemble de nos modèles. Par conséquent, le composé semblerait induire les cellules souches vers un phénotype différencié au moins pour la lignée DAOY, même si les mécanismes n’ont pas pu être clairement élucidé. En conclusion, l’inhibition de NRP-1 via MR438 semble stimuler la différenciation des cellules souches cancéreuses pouvant à terme réduire la progression du MB et apporter un bénéfice en association avec la radiothérapie. L’evaluation du composé sur des modèles orthotopiques de MB permettrait d’obtenir des informations quant à son efficacité sur des modèles plus proche de la physiopathologie tenant compte de sa distribution au niveau cérébral

Devant la multitude de médicaments disponibles sur le marché avec ou sans prescriptionmédicale, il est difficile de savoir pour un sportif si oui ou non il est possible d'utiliser unmédicament sans risquer d'être contrôlé positif au dépistage du dopage. Il existe denombreux cas de dopages accidentels ou un sportif a utilisé sans conseil ni recommandationune spécialité disponible en pharmacie.Afin d'essayer de stopper ce phénomène le pharmacien d'officine est le mieux placé pourmettre en garde les sportifs sur les risques qui existent avec de nombreux médicaments de sedoper sans le vouloir. De plus le pharmacien est en première ligne pour signaler et prévenirles cas de dopage volontaires. Grace à ses connaissances le pharmacien va orienter le sportifsur le choix de la molécule à utiliser afin de traiter sa pathologie, il va pouvoir lui expliquercomment faire bon usage du médicament, c'est son rôle principal vis-à-vis du patient.