Severine Loisel - Academia.edu (original) (raw)

Papers by Severine Loisel

Research paper thumbnail of CS14-6. Development of two IL15 immunocytokines targeting either GD2- or CD20- tumoral bearing cells

Research paper thumbnail of SFRP CO-08 – Conséquence d’une antibiothérapie néonatale sur la barrière intestinale du raton

Archives de Pédiatrie, 2014

Objectifs L’antibiotherapie neonatale modifie t’elle les fonctions et le controle par le systeme ... more Objectifs L’antibiotherapie neonatale modifie t’elle les fonctions et le controle par le systeme nerveux enterique des fonctions digestives ? Materiels et methodes du Metronidazole etait administre per os a des ratons Spragues Dawley (7,5 g/kg/j) de J1 a J21 (AB). In vivo , les temps de transit, et la permeabilite paracellulaire intestinale par dosage sanguin de fluoresceine ingeree ou par mesure endoscopique en microscopie confocale de fluorescence apres injection IV etaient mesures. Ex vivo , la permeabilite et la morphologie histologique du colon etaient analysees apres 15 jours. Resultats principaux A J21, le temps de transit est analogue, la permeabilite paracellulaire in vivo est augmentee dans le groupe AB. Apres 15 jours, le temps de transit est plus court et e x vivo , la permeabilite colique proximale est augmentee dans le groupe AB. Histologiquement, sans changement morphologique, le nombre de mitoses et de cellules inflammatoires diminuait dans le groupe AB (0,4 vs 0,2 et 1,2 0,17 vs 1,04). En microscopie confocale, dans le groupe AB, les cryptes sont moins arrondies (L/l = 2.7 vs 1,8). Conclusion L’antibiotherapie neonatale entraine des modifications fonctionnelles du tube digestif, et des alterations microscopiques de la barriere epitheliale persistante.

Research paper thumbnail of EP1119 Fischer rate 344 with syngeneic epithelial ovarian cancer (EOC) cells NuTu 19: key points for building a reliable ovarian carcinomatosis animal model

ePoster, 2019

Introduction/Background Animal models are required for better understanding of EOC natural histor... more Introduction/Background Animal models are required for better understanding of EOC natural history and therapy assay. We set up an experimental peritoneal carcinomatosis in an immunocompetent female rat model Fischer F 344 using a syngeneic epithelial ovarian cancer cell line NuTu 19. Methodology Twenty height female Fischer rats' F 344 were used in keeping with ethical in animal testing. NuTu19 were transfected using the lipophosphoramid KLN-47 reagent carrying the luciferase-encoding plasmid pTG11033. NuTu 19 Luc+ cells were injected into the peritoneum in the left iliac fossa with various concentration and dilution. Bioluminescence monitoring was performed day 4, 10, 17, 25, 31, 38 and 49. Surgery was performed under general anesthesia and pain management at day 17, 31, 49, 77. Two Peritoneal Carcinomatosis Index (PCI) were used. Results Significant luciferase-activity was observed 24 hours following the injection, increased gradually and stabilising from day 10 (table 1). Site-injection and sub-diaphragmatic areas were the two most common bioluminescent locations whatever cell concentration. Macroscopic tumour graft was found delayed at day 21 and Iterative surgery show increasing PCI over time. Medium PCI 1 was 22.5 [17–41] and PCI 2 22 [13–29]. Pathological exam (PE) was performed in 21 rates and results did not correlate with PCI and bioluminescence. Lymphoid hyperplasia without carcinomatosis was found for low PCI (<6) in four rates, however high PCI (>12) were associated with tumour graft at PE. No carcinomatosis was found at PE before day 10 and bioluminescence's positive predictive value was 62.5% from day 35. Conclusion Developing a non-short term -life-threatening microscopic homogeneous carcinomatosis remains a challenge for in-vivo therapy assay. The choice of a suitable animal model for surgery requires high quality experimental plan and systematic sampling for pathological exam to avoid incorrect assessment. Disclosure Nothing to disclose Abstract EP1119 Figure 1 Bioluminescent Imaging

Research paper thumbnail of Identification of ras/raf binding site and design of interfering peptide with potential clinical application

Integrative molecular medicine, 2016

Despite intensive effort, no effective pharmacological inhibitors of the Ras oncoprotein have bee... more Despite intensive effort, no effective pharmacological inhibitors of the Ras oncoprotein have been reached the clinic given the impression that Ras proteins are undruggable. However, progresses have been made in several directions to manipulate Ras. In this manuscript, we describe a novel and promising approach for specifically targeting the Ras/Raf interaction. We have identified the amino acid sequence involved in the binding of Ras to Raf. The amino acids of the binding site were coupled to an optimized penetrating peptide in order to generate a chimeric peptide, Mut3DPT-Ras, able to penetrate the cells and target Ras/Raf interaction. We demonstrate that this protease-resistant peptide has an in vitro apoptotic effect on several cancer cell lines and on primary cells isolated from chronic lymphocytic leukemia (CLL) as well as an antitumoral effect on chronic lymphocytic leukemialike and lymphoma xenograft model. The new generated peptide allows the modulation of the Ras/Raf interaction and might have a potential as a new therapeutic approach for cancer treatment.

Research paper thumbnail of Optimisation et limites du transfert de gènes par voie intraveineuse à l'aide de vecteurs non viraux de type lipides cationiques chez la souris Swiss : application à une thérapie génique de la mucoviscidose (doctorat : sciences de la vie et de la santé)

Research paper thumbnail of Contribution of Plasmid DNA to Hepatotoxicity after Systemic Administration of Lipoplexes

Human Gene Therapy, Apr 10, 2001

Several studies have demonstrated that intravenous administration of DNA complexed with cationic ... more Several studies have demonstrated that intravenous administration of DNA complexed with cationic lipid vectors induces the production of large quantities of proinflammatory cytokines. In this study we confirm these observations, using cationic lipid DOTAP and cationic phospholipid compounds. Moreover, we demonstrate that although intravenous administration of lipid-DNA complexes does not induce toxic effects in the lung, high transgene expression in lung correlates with histopathological lesions in liver, this fact being documented by high transaminase levels in serum of treated mice. We examine the contribution of various components of the lipoplexes in this observed liver toxicity, as well as in the increasing level of transaminases, and more particularly the role of nonmethylated CpG sequences of plasmid DNA. We show that blood samples from animals treated either with cationic lipid alone, or with cationic lipid complexed with methylated plasmid DNA, contain low levels of transaminases. The significant decrease in transaminase levels after injection of cationic lipid-methylated pDNA complexes leads us to believe that nonmethylated CpG sequences could play a major role in this hepatoxicity. Similar results were observed when using a vector that did not encode a transgene, demonstrating that the expression of luciferase in lung was not responsible for this liver toxicity. All these observations suggest that significant work should be devoted to understand more clearly the mechanism of cationic lipid-DNA complex toxicity, and to overcome the problems subsequent to administration of nonmethylated CpG sequences of plasmid DNA.

Research paper thumbnail of Factors Influencing the Efficiency of Lipoplexes Mediated Gene Transfer in Lung After Intravenous Administration*

Journal of Liposome Research, 2001

The objectives of this study were to test the influence of different parameters on the in vivo ca... more The objectives of this study were to test the influence of different parameters on the in vivo cationic lipid mediated gene transfer in lung after intravenous administration. Luciferase activity was evaluated in lung tissue 24 hours after intravenous administration of different types of lipoplexes. These included lipoplexes prepared using cationic phosphonolipids or DOTAP and various amounts of plasmid DNA. Using two different plasmids we tested the influence of plasmid size on transfection efficiency in vivo. In a last series of experiments, lipoplexes were prepared using different excipients (water, NaCl or 5% glucose solution) and three injection volumes were tested. We demonstrate that chemical structure modifications such as cation substitution and increment of the aliphatic chain length significantly improve transfection efficiency. High luciferase levels are obtained by increasing lipid to DNA charge ratio and plasmid DNA dose and decreasing plasmid size. Lipoplexes prepared in physiological NaCl solution and injected using a volume of 800mul are significantly the most effective. Cationic lipid mediated gene transfer in lung tissue after intravenous administration is influenced by factors including cationic lipid chemical structure, lipid to DNA ratio and plasmid dose. Nevertheless, plasmid size, injection volume and the excipient, used for the lipoplexes preparation, are also important factors and must be considered for an optimization of in vivo gene delivery using intravenous administration.

Research paper thumbnail of Cationic Phosphonolipids as Nonviral Vectors: In Vitro and in Vivo Applications

Journal of Pharmaceutical Sciences, May 1, 2000

Since the development of the concept of gene therapy using cationic lipids as nonviral vectors by... more Since the development of the concept of gene therapy using cationic lipids as nonviral vectors by Felgner's group in 1987, numerous molecules have been synthesized. Such vectors were first proposed to avoid viral vector-induced drawbacks. But, it quickly became clear that a thorough knowledge of their physical and chemical characteristics was fundamental to use them under optima conditions. Over the last years our laboratory has developed a family of cationic lipids called phosphonolipids whose structure is based on that of natural phosphonolipids; compared with other vectors, these compounds had to be well-tolerated by biologic membranes. Some of our synthesized molecules exhibited an interesting potential for gene transfer, both in vitro and in vivo. Structural changes in the different parts (hydrophobic, hydrophilic, and intermediary domains) of these vectors were evaluated in vitro on different cell-lines; these studies led us to select some of these molecules to carry out in vivo tests. So, the plasmid/phosphonolipid complexes were first administered to mice by intratracheal and aerosol routes with a ␤-galactosidase plasmid as reporter gene. In a second set of experiments, we explored the possibilities offered by intravenous injection; in these studies, we used a luciferase plasmid as reporter gene because of its high sensibility. These experiments revealed a transgene expression essentially localized in the lungs. In a further study, we compared systemic administration with local ones; we, then, observed that the optimum formulation of a given molecule depended on its route of administration.

Research paper thumbnail of Cation Substitution in Cationic Phosphonolipids: A New Concept To Improve Transfection Activity and Decrease Cellular Toxicity

Journal of Medicinal Chemistry, Nov 1, 2000

Cationic lipids have been shown to be an interesting alternative to viral vector-mediated gene de... more Cationic lipids have been shown to be an interesting alternative to viral vector-mediated gene delivery into in vitro and in vivo model applications. Prior studies have demonstrated that even minor structural modifications of the lipid hydrophobic domain or of the lipid polar domain result in significant changes in gene delivery efficiency. Previously, we developed a novel class of cationic lipids called cationic phosphonolipids and described the ability of these vectors to transfer DNA into different cell lines and in vivo. Up until now, in all new cationic lipids, nitrogen atoms have always carried the cationic or polycationic charge. Recently we have developed a new series of cationic phosphonolipids characterized by a cationic charge carried by a phosphorus or arsenic atom. In a second step, we have also examined the effects of the linker length between the cation and the hydrophobic domain as regards transfection activity. Transfection activities of this library of new cationic phosphonolipids were studied in vitro in different cell lines (HeLa, CFT1, K562) and in vivo using a luciferase reporter gene. A luminescent assay was carried out to assess luciferase expression. We demonstrated that cation substitution on the polar domain of cationic phosphonolipids (N --&gt; P or As) results in significant increase in transfection activity for both in vitro and in vivo assays and decrease of cellular toxicity.

Research paper thumbnail of In Silico and In Vivo Studies of a Tumor-Penetrating and Interfering Peptide with Antitumoral Effect on Xenograft Models of Breast Cancer

Pharmaceutics, Apr 7, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Preclinical Validation of Tumor-Penetrating and Interfering Peptides against Chronic Lymphocytic Leukemia

Molecular Pharmaceutics, Feb 3, 2022

Chronic lymphocytic leukemia (CLL) is the most common form of leukemia in adults. This pathology ... more Chronic lymphocytic leukemia (CLL) is the most common form of leukemia in adults. This pathology The disease is characterized by the accumulation of tumoral B cells resulting from a defect of apoptosis. We have in vitro and in vivo preclinically validated a tumor-penetrating peptide (named TT1) coupled to an interfering peptide (IP) that dissociates the interaction between the serine/threonine protein phosphatase 2A (PP2A) from its physiological inhibitor, the oncoprotein SET. P2A PP2A/SET This TT1-IP peptide has anti-tumoral effect on CLL, as shown by the increased survival of mice bearing xenograft models of CLL, compared to control mice. The peptide did not show toxicity, as indicated by the mouse body weight and the biochemical parameters, such as renal and hepatic enzymes. In addition, the peptide induced apoptosis in vitro of primary tumoral B cells isolated from CLL patients but not of those isolated from healthy patients. Finally, the peptide had around approximately 5 hours half-life in human serum and showed pharmacokinetic parameters compatible with clinical development as therapeutic peptide against CLL.

Research paper thumbnail of A case for the graft-versus-host disease as a model for B cell-mediated autoimmunity

Autoimmunity Reviews, Feb 1, 2011

Following allogenic hematopoietic stem cell transplantation (HSCT), patients with autoimmune dise... more Following allogenic hematopoietic stem cell transplantation (HSCT), patients with autoimmune disease or hematopoietic malignancy may develop acute or chronic graft-versus-host (GvH) disease. B lymphocytes, from the recipient as well as from the donor, have recently been implicated in the pathogenesis of such disturbances. Their deleterious effects are accounted for by other tasks B lymphocytes accomplish than the antibody production. We highlight herein some recent observations in the context of B cells in the GvH disease.

Research paper thumbnail of Cationic Phosphonolipids Containing Quaternary Phosphonium and Arsonium Groups for DNA Transfection with Good Efficiency and Low Cellular Toxicity**

Angewandte Chemie, Feb 4, 2000

Replacing the ammonium polar head in cationic lipids 1 (A=N) by a phosphonium or an arsonium grou... more Replacing the ammonium polar head in cationic lipids 1 (A=N) by a phosphonium or an arsonium group (A=P, As) improves their properties as synthetic vectors for DNA transfection. The increased volume of the cationic head is supposed to modify the interactions of the vector with the solvent and DNA.

Research paper thumbnail of Updating the Physiology, Exploration and Disease Relevance of Complement Factor H

International Journal of Immunopathology and Pharmacology, Apr 1, 2010

The factor H (FH) protein (also known as ptH globulin) is the main regulator of the complement al... more The factor H (FH) protein (also known as ptH globulin) is the main regulator of the complement alternative pathway. It exhibits multivalent binding sites to the complement component C3b, and polyanions and one binding site to sialic acid and cell surfaces. These multiple binding sites confer to FH a decay-accelerating factor activity in the fluid phase as well as at the cell surface. A defect in FH activity or a FH protein deficiency triggers chronic inflammation and tissue injury, leading to various disorders impacting the kidney or the eye. In contrast, some pathogens, as well as cancer cells, develop various strategies to bind FH and thereby subvert a complement attack. We focus on the functions of FH, and review the main pathological conditions in which FH is involved. Since the pathogenesis is elusive, appropriate FH dosage in biological fluids and FH gene analysis may help in improving understanding of such diseases. The factor H (FH) protein, originally identified as 1H globulin in 1965 (l), is a 155,000 dalton single polypeptide chain which negatively regulates the complement cascade. FH controls the complement component 3 (C3) and modulates many of its functions. In this review, we describe FH physiology and especially its biological functions. We are also interested in the main diseases in which FH is involved and in diagnostic tests which may be relevant in clinics. Factor H:from gene(s) to protein(s) expression and regulation The human FH gene, mapped to chromosome I both in humans and mice, is located in the regulator of complement activation (RCA) gene cluster in 1q32 (2). Northern-blot analyses of human liver mRNA report two other mRNAs, which are alternative-splicing-variants ofFH mRNA, encoding respectively the factor H-like 1 (FLH-1; 43,000 Da) and another protein (37,000 Da), which is less known (3). In addition, five FH allelic variants, located close to the FH gene in the RCA gene cluster (4), encode for FH related-proteins (FHR1 to FHR5). The FH protein is a 155,000 Da single polypeptide chain composed of twenty short consensus repeats (SCR) (5). Structural studies on the flexibility and size of FH suggest that FH SCR domains are bent back upon themselves. Moreover, the peptidic sequence and length of SCR domains influence the interaction between FH and multivalent ligands. FH (as FHL-1) is constitutively produced by the liver but other cells can produce FH (monocytes, keratinocytes, fibroblasts, oligodendrocytes or

Research paper thumbnail of Systemic administration of cationic phosphonolipids/DNA complexes and the relationship between formulation and lung transfection efficiency

Biochimica et Biophysica Acta (BBA) - Biomembranes, 2000

Performances of cationic lipid formulations for intravenous gene delivery to mouse lungs have bee... more Performances of cationic lipid formulations for intravenous gene delivery to mouse lungs have been previously reported. We report in this study that cationic phosphonolipids, when appropriately formulated, can be good synthetic vectors for gene delivery to lung after intravenous administration. One of our reagents, GLB43, was capable of mediating a 500-fold higher expression in the lungs of mice than could be obtained with free pDNA alone (P = 0.018). We demonstrate that the most important parameters for cationic phosphonolipid transfection activity after systemic administration are the chemical structure of the cationic phosphonolipid, the lipid to DNA charge ratio and the inclusion of co-lipid in the formulation. We report using a luciferase reporter gene that transfection activity in vivo 24 h after cationic phosphonolipid systemic administration could not be predicted from in vitro analysis. In contrast to in vitro studies, cationic phosphonolipids including the oleyl acyl chains (GLB43) were more effective than its analogue with the myristyl acyl chains (GLB73). Using pathological analysis of animal livers, we demonstrate that the toxicity level was correlated with the lipoplex formulation and the lipid to DNA ratio.

Research paper thumbnail of In Silico and In Vivo Studies of a Tumor-Penetrating and Interfering Peptide with Antitumoral Effect on Xenograft Models of Breast Cancer

Pharmaceutics, Apr 7, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Recombinant humanised anti-HER2/neu antibody (Herceptin®) induces cellular death of glioblastomas

British Journal of Cancer, 2004

Glioblastoma multiforme (GBM) remains the most devastating primary tumour in neuro-oncology. Targ... more Glioblastoma multiforme (GBM) remains the most devastating primary tumour in neuro-oncology. Targeting of the human epithelial receptor type 2 (HER2)-neu receptor by specific antibodies is a recent well-established therapy for breast tumours. Human epithelial receptor type 2/neu is a transmembrane tyrosine/kinase receptor that appears to be important for the regulation of cancer growth. Human epithelial receptor type 2/neu is not expressed in the adult central nervous system, but its expression increases with the degree of astrocytoma anaplasia. The specificity of HER2/neu for tumoral astrocytomas leads us to study in vitro treatment of GBM with anti-HER2/neu antibody. We used human GBM cell lines expressing HER2/neu (A172 express HER2/neu more than U251MG) or not (U87MG) and monoclonal humanised antibody against HER2/neu (Herceptin s). Human epithelial receptor type 2/neu expression was measured by immunohistochemistry and flow cytometry. Direct antibody effect, complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity were evaluated by different cytometric assays. We have shown, for the first time, the ability of anti-HER2/neu antibodies to induce apoptosis and cellular-dependent cytotoxicity of HER2/neu-expressing GBM cell lines. The results decreased from A172 to U251 and were negative for U87MG, in accordance with the decreasing density of HER2/neu receptors.

Research paper thumbnail of Increasing of HER2 membranar density in human glioblastoma U251MG cell line established in a new nude mice model

Journal of Neuro-Oncology, 2007

Research paper thumbnail of BAFF-modulated repopulation of B lymphocytes in the blood and salivary glands of RITUXIMAB-TREATED patients with Sjögren's syndrome

Arthritis & Rheumatism, 2007

Treatment with rituximab depletes B cells from the peripheral blood (PB) and salivary glands (SGs... more Treatment with rituximab depletes B cells from the peripheral blood (PB) and salivary glands (SGs) of patients with primary Sjögren&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s syndrome (SS). The purpose of this study was to track the repopulation of B cell subsets in PB as well as their subsequent homing into SGs in patients with primary SS treated with rituximab. A series of 4-color flow cytometry experiments delineated B cell subsets in 15 patients with primary SS. All were tested on days 8 and 15 of treatment. Nine of the patients were followed up monthly for 10 months, and the remaining 6 patients were followed up monthly for 24 months. Enzyme-linked immunosorbent assays were developed to measure serum levels of BAFF and rituximab. SGs were biopsied at the start of the study and 4 months after treatment in 15 patients, 12 months after treatment in 3 patients, and 24 months after treatment in 2 patients. Baseline serum levels of BAFF correlated inversely (r = -0.92, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 5 x 10(-4)) with the duration of B cell depletion: the higher the BAFF levels, the shorter the duration of B cell depletion. Four B cell subsets repopulated the PB: plasmablasts (CD19+, CD5-,IgD-,CD38++), transitional type 1 (T1) B cells (CD19+,CD5+,IgD+,CD38++), mature Bm2 cells (CD19+,CD5+/-,IgD+,CD38+/-), and memory B cells (CD19+,CD5-,IgD-,CD38-). Increased numbers of Bm2 cells and decreased memory B cells reappeared with time. Sequential SG biopsies revealed that B cells were absent in these glands for 12 months: they were detected 24 months after rituximab treatment. Memory and T1 B cells were the first B cells identified locally. The timing of B cell repopulation is modulated by BAFF and is followed by reconstitution of the preexisting abnormalities.

Research paper thumbnail of Is the c-Cbl Proto-Oncogene Involved in Chronic Lymphocytic Leukemia?

Annals of the New York Academy of Sciences, 2007

Chronic lymphocytic leukemia (CLL) is characterized by survival advantage and accumulation of CD5... more Chronic lymphocytic leukemia (CLL) is characterized by survival advantage and accumulation of CD5+ mature B lymphocytes. Expression of zeta-chain-associated protein-70 (ZAP-70), normally present in T lymphocytes or immature B cells, is associated with disease aggressiveness, as IgVH mutational status, and some proteins implicated in survival signal pathways are found to be constitutively activated in CLL cells. ZAP-70 signaling is regulated through molecular adaptors, such as the proto-oncogene product c-Casitas B lineage lymphoma (c-Cbl). The aim of this study was to determine the implication of this proto-oncogene product in CLL in survival signals. It appeared that expression of c-Cbl was increased in CLL and not correlated to that of B cell linker protein or ZAP-70. Furthermore, c-Cbl was significantly hypophosphorylated in progressive disease, so that hypophosphorylated form of c-Cbl (c-Cbl.P) along with ZAP-70, set a cutoff ratio distributing patients with stable situation below 1, and those with progressive disease equal or above 1. Given that phospholipase gamma 2 (PLC␥2) function is also influenced by c-Cbl hypophosphorylation, the ratio of PLC␥2 to c-Cbl.P was measured in CLL B cells and consistently found to be ≥ 1 in Binet stage B CLL patients, as opposed to stage A CLL patients. These findings invite analysis of the role of c-Cbl in CLL.

Research paper thumbnail of CS14-6. Development of two IL15 immunocytokines targeting either GD2- or CD20- tumoral bearing cells

Research paper thumbnail of SFRP CO-08 – Conséquence d’une antibiothérapie néonatale sur la barrière intestinale du raton

Archives de Pédiatrie, 2014

Objectifs L’antibiotherapie neonatale modifie t’elle les fonctions et le controle par le systeme ... more Objectifs L’antibiotherapie neonatale modifie t’elle les fonctions et le controle par le systeme nerveux enterique des fonctions digestives ? Materiels et methodes du Metronidazole etait administre per os a des ratons Spragues Dawley (7,5 g/kg/j) de J1 a J21 (AB). In vivo , les temps de transit, et la permeabilite paracellulaire intestinale par dosage sanguin de fluoresceine ingeree ou par mesure endoscopique en microscopie confocale de fluorescence apres injection IV etaient mesures. Ex vivo , la permeabilite et la morphologie histologique du colon etaient analysees apres 15 jours. Resultats principaux A J21, le temps de transit est analogue, la permeabilite paracellulaire in vivo est augmentee dans le groupe AB. Apres 15 jours, le temps de transit est plus court et e x vivo , la permeabilite colique proximale est augmentee dans le groupe AB. Histologiquement, sans changement morphologique, le nombre de mitoses et de cellules inflammatoires diminuait dans le groupe AB (0,4 vs 0,2 et 1,2 0,17 vs 1,04). En microscopie confocale, dans le groupe AB, les cryptes sont moins arrondies (L/l = 2.7 vs 1,8). Conclusion L’antibiotherapie neonatale entraine des modifications fonctionnelles du tube digestif, et des alterations microscopiques de la barriere epitheliale persistante.

Research paper thumbnail of EP1119 Fischer rate 344 with syngeneic epithelial ovarian cancer (EOC) cells NuTu 19: key points for building a reliable ovarian carcinomatosis animal model

ePoster, 2019

Introduction/Background Animal models are required for better understanding of EOC natural histor... more Introduction/Background Animal models are required for better understanding of EOC natural history and therapy assay. We set up an experimental peritoneal carcinomatosis in an immunocompetent female rat model Fischer F 344 using a syngeneic epithelial ovarian cancer cell line NuTu 19. Methodology Twenty height female Fischer rats' F 344 were used in keeping with ethical in animal testing. NuTu19 were transfected using the lipophosphoramid KLN-47 reagent carrying the luciferase-encoding plasmid pTG11033. NuTu 19 Luc+ cells were injected into the peritoneum in the left iliac fossa with various concentration and dilution. Bioluminescence monitoring was performed day 4, 10, 17, 25, 31, 38 and 49. Surgery was performed under general anesthesia and pain management at day 17, 31, 49, 77. Two Peritoneal Carcinomatosis Index (PCI) were used. Results Significant luciferase-activity was observed 24 hours following the injection, increased gradually and stabilising from day 10 (table 1). Site-injection and sub-diaphragmatic areas were the two most common bioluminescent locations whatever cell concentration. Macroscopic tumour graft was found delayed at day 21 and Iterative surgery show increasing PCI over time. Medium PCI 1 was 22.5 [17–41] and PCI 2 22 [13–29]. Pathological exam (PE) was performed in 21 rates and results did not correlate with PCI and bioluminescence. Lymphoid hyperplasia without carcinomatosis was found for low PCI (<6) in four rates, however high PCI (>12) were associated with tumour graft at PE. No carcinomatosis was found at PE before day 10 and bioluminescence's positive predictive value was 62.5% from day 35. Conclusion Developing a non-short term -life-threatening microscopic homogeneous carcinomatosis remains a challenge for in-vivo therapy assay. The choice of a suitable animal model for surgery requires high quality experimental plan and systematic sampling for pathological exam to avoid incorrect assessment. Disclosure Nothing to disclose Abstract EP1119 Figure 1 Bioluminescent Imaging

Research paper thumbnail of Identification of ras/raf binding site and design of interfering peptide with potential clinical application

Integrative molecular medicine, 2016

Despite intensive effort, no effective pharmacological inhibitors of the Ras oncoprotein have bee... more Despite intensive effort, no effective pharmacological inhibitors of the Ras oncoprotein have been reached the clinic given the impression that Ras proteins are undruggable. However, progresses have been made in several directions to manipulate Ras. In this manuscript, we describe a novel and promising approach for specifically targeting the Ras/Raf interaction. We have identified the amino acid sequence involved in the binding of Ras to Raf. The amino acids of the binding site were coupled to an optimized penetrating peptide in order to generate a chimeric peptide, Mut3DPT-Ras, able to penetrate the cells and target Ras/Raf interaction. We demonstrate that this protease-resistant peptide has an in vitro apoptotic effect on several cancer cell lines and on primary cells isolated from chronic lymphocytic leukemia (CLL) as well as an antitumoral effect on chronic lymphocytic leukemialike and lymphoma xenograft model. The new generated peptide allows the modulation of the Ras/Raf interaction and might have a potential as a new therapeutic approach for cancer treatment.

Research paper thumbnail of Optimisation et limites du transfert de gènes par voie intraveineuse à l'aide de vecteurs non viraux de type lipides cationiques chez la souris Swiss : application à une thérapie génique de la mucoviscidose (doctorat : sciences de la vie et de la santé)

Research paper thumbnail of Contribution of Plasmid DNA to Hepatotoxicity after Systemic Administration of Lipoplexes

Human Gene Therapy, Apr 10, 2001

Several studies have demonstrated that intravenous administration of DNA complexed with cationic ... more Several studies have demonstrated that intravenous administration of DNA complexed with cationic lipid vectors induces the production of large quantities of proinflammatory cytokines. In this study we confirm these observations, using cationic lipid DOTAP and cationic phospholipid compounds. Moreover, we demonstrate that although intravenous administration of lipid-DNA complexes does not induce toxic effects in the lung, high transgene expression in lung correlates with histopathological lesions in liver, this fact being documented by high transaminase levels in serum of treated mice. We examine the contribution of various components of the lipoplexes in this observed liver toxicity, as well as in the increasing level of transaminases, and more particularly the role of nonmethylated CpG sequences of plasmid DNA. We show that blood samples from animals treated either with cationic lipid alone, or with cationic lipid complexed with methylated plasmid DNA, contain low levels of transaminases. The significant decrease in transaminase levels after injection of cationic lipid-methylated pDNA complexes leads us to believe that nonmethylated CpG sequences could play a major role in this hepatoxicity. Similar results were observed when using a vector that did not encode a transgene, demonstrating that the expression of luciferase in lung was not responsible for this liver toxicity. All these observations suggest that significant work should be devoted to understand more clearly the mechanism of cationic lipid-DNA complex toxicity, and to overcome the problems subsequent to administration of nonmethylated CpG sequences of plasmid DNA.

Research paper thumbnail of Factors Influencing the Efficiency of Lipoplexes Mediated Gene Transfer in Lung After Intravenous Administration*

Journal of Liposome Research, 2001

The objectives of this study were to test the influence of different parameters on the in vivo ca... more The objectives of this study were to test the influence of different parameters on the in vivo cationic lipid mediated gene transfer in lung after intravenous administration. Luciferase activity was evaluated in lung tissue 24 hours after intravenous administration of different types of lipoplexes. These included lipoplexes prepared using cationic phosphonolipids or DOTAP and various amounts of plasmid DNA. Using two different plasmids we tested the influence of plasmid size on transfection efficiency in vivo. In a last series of experiments, lipoplexes were prepared using different excipients (water, NaCl or 5% glucose solution) and three injection volumes were tested. We demonstrate that chemical structure modifications such as cation substitution and increment of the aliphatic chain length significantly improve transfection efficiency. High luciferase levels are obtained by increasing lipid to DNA charge ratio and plasmid DNA dose and decreasing plasmid size. Lipoplexes prepared in physiological NaCl solution and injected using a volume of 800mul are significantly the most effective. Cationic lipid mediated gene transfer in lung tissue after intravenous administration is influenced by factors including cationic lipid chemical structure, lipid to DNA ratio and plasmid dose. Nevertheless, plasmid size, injection volume and the excipient, used for the lipoplexes preparation, are also important factors and must be considered for an optimization of in vivo gene delivery using intravenous administration.

Research paper thumbnail of Cationic Phosphonolipids as Nonviral Vectors: In Vitro and in Vivo Applications

Journal of Pharmaceutical Sciences, May 1, 2000

Since the development of the concept of gene therapy using cationic lipids as nonviral vectors by... more Since the development of the concept of gene therapy using cationic lipids as nonviral vectors by Felgner's group in 1987, numerous molecules have been synthesized. Such vectors were first proposed to avoid viral vector-induced drawbacks. But, it quickly became clear that a thorough knowledge of their physical and chemical characteristics was fundamental to use them under optima conditions. Over the last years our laboratory has developed a family of cationic lipids called phosphonolipids whose structure is based on that of natural phosphonolipids; compared with other vectors, these compounds had to be well-tolerated by biologic membranes. Some of our synthesized molecules exhibited an interesting potential for gene transfer, both in vitro and in vivo. Structural changes in the different parts (hydrophobic, hydrophilic, and intermediary domains) of these vectors were evaluated in vitro on different cell-lines; these studies led us to select some of these molecules to carry out in vivo tests. So, the plasmid/phosphonolipid complexes were first administered to mice by intratracheal and aerosol routes with a ␤-galactosidase plasmid as reporter gene. In a second set of experiments, we explored the possibilities offered by intravenous injection; in these studies, we used a luciferase plasmid as reporter gene because of its high sensibility. These experiments revealed a transgene expression essentially localized in the lungs. In a further study, we compared systemic administration with local ones; we, then, observed that the optimum formulation of a given molecule depended on its route of administration.

Research paper thumbnail of Cation Substitution in Cationic Phosphonolipids: A New Concept To Improve Transfection Activity and Decrease Cellular Toxicity

Journal of Medicinal Chemistry, Nov 1, 2000

Cationic lipids have been shown to be an interesting alternative to viral vector-mediated gene de... more Cationic lipids have been shown to be an interesting alternative to viral vector-mediated gene delivery into in vitro and in vivo model applications. Prior studies have demonstrated that even minor structural modifications of the lipid hydrophobic domain or of the lipid polar domain result in significant changes in gene delivery efficiency. Previously, we developed a novel class of cationic lipids called cationic phosphonolipids and described the ability of these vectors to transfer DNA into different cell lines and in vivo. Up until now, in all new cationic lipids, nitrogen atoms have always carried the cationic or polycationic charge. Recently we have developed a new series of cationic phosphonolipids characterized by a cationic charge carried by a phosphorus or arsenic atom. In a second step, we have also examined the effects of the linker length between the cation and the hydrophobic domain as regards transfection activity. Transfection activities of this library of new cationic phosphonolipids were studied in vitro in different cell lines (HeLa, CFT1, K562) and in vivo using a luciferase reporter gene. A luminescent assay was carried out to assess luciferase expression. We demonstrated that cation substitution on the polar domain of cationic phosphonolipids (N --&gt; P or As) results in significant increase in transfection activity for both in vitro and in vivo assays and decrease of cellular toxicity.

Research paper thumbnail of In Silico and In Vivo Studies of a Tumor-Penetrating and Interfering Peptide with Antitumoral Effect on Xenograft Models of Breast Cancer

Pharmaceutics, Apr 7, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Preclinical Validation of Tumor-Penetrating and Interfering Peptides against Chronic Lymphocytic Leukemia

Molecular Pharmaceutics, Feb 3, 2022

Chronic lymphocytic leukemia (CLL) is the most common form of leukemia in adults. This pathology ... more Chronic lymphocytic leukemia (CLL) is the most common form of leukemia in adults. This pathology The disease is characterized by the accumulation of tumoral B cells resulting from a defect of apoptosis. We have in vitro and in vivo preclinically validated a tumor-penetrating peptide (named TT1) coupled to an interfering peptide (IP) that dissociates the interaction between the serine/threonine protein phosphatase 2A (PP2A) from its physiological inhibitor, the oncoprotein SET. P2A PP2A/SET This TT1-IP peptide has anti-tumoral effect on CLL, as shown by the increased survival of mice bearing xenograft models of CLL, compared to control mice. The peptide did not show toxicity, as indicated by the mouse body weight and the biochemical parameters, such as renal and hepatic enzymes. In addition, the peptide induced apoptosis in vitro of primary tumoral B cells isolated from CLL patients but not of those isolated from healthy patients. Finally, the peptide had around approximately 5 hours half-life in human serum and showed pharmacokinetic parameters compatible with clinical development as therapeutic peptide against CLL.

Research paper thumbnail of A case for the graft-versus-host disease as a model for B cell-mediated autoimmunity

Autoimmunity Reviews, Feb 1, 2011

Following allogenic hematopoietic stem cell transplantation (HSCT), patients with autoimmune dise... more Following allogenic hematopoietic stem cell transplantation (HSCT), patients with autoimmune disease or hematopoietic malignancy may develop acute or chronic graft-versus-host (GvH) disease. B lymphocytes, from the recipient as well as from the donor, have recently been implicated in the pathogenesis of such disturbances. Their deleterious effects are accounted for by other tasks B lymphocytes accomplish than the antibody production. We highlight herein some recent observations in the context of B cells in the GvH disease.

Research paper thumbnail of Cationic Phosphonolipids Containing Quaternary Phosphonium and Arsonium Groups for DNA Transfection with Good Efficiency and Low Cellular Toxicity**

Angewandte Chemie, Feb 4, 2000

Replacing the ammonium polar head in cationic lipids 1 (A=N) by a phosphonium or an arsonium grou... more Replacing the ammonium polar head in cationic lipids 1 (A=N) by a phosphonium or an arsonium group (A=P, As) improves their properties as synthetic vectors for DNA transfection. The increased volume of the cationic head is supposed to modify the interactions of the vector with the solvent and DNA.

Research paper thumbnail of Updating the Physiology, Exploration and Disease Relevance of Complement Factor H

International Journal of Immunopathology and Pharmacology, Apr 1, 2010

The factor H (FH) protein (also known as ptH globulin) is the main regulator of the complement al... more The factor H (FH) protein (also known as ptH globulin) is the main regulator of the complement alternative pathway. It exhibits multivalent binding sites to the complement component C3b, and polyanions and one binding site to sialic acid and cell surfaces. These multiple binding sites confer to FH a decay-accelerating factor activity in the fluid phase as well as at the cell surface. A defect in FH activity or a FH protein deficiency triggers chronic inflammation and tissue injury, leading to various disorders impacting the kidney or the eye. In contrast, some pathogens, as well as cancer cells, develop various strategies to bind FH and thereby subvert a complement attack. We focus on the functions of FH, and review the main pathological conditions in which FH is involved. Since the pathogenesis is elusive, appropriate FH dosage in biological fluids and FH gene analysis may help in improving understanding of such diseases. The factor H (FH) protein, originally identified as 1H globulin in 1965 (l), is a 155,000 dalton single polypeptide chain which negatively regulates the complement cascade. FH controls the complement component 3 (C3) and modulates many of its functions. In this review, we describe FH physiology and especially its biological functions. We are also interested in the main diseases in which FH is involved and in diagnostic tests which may be relevant in clinics. Factor H:from gene(s) to protein(s) expression and regulation The human FH gene, mapped to chromosome I both in humans and mice, is located in the regulator of complement activation (RCA) gene cluster in 1q32 (2). Northern-blot analyses of human liver mRNA report two other mRNAs, which are alternative-splicing-variants ofFH mRNA, encoding respectively the factor H-like 1 (FLH-1; 43,000 Da) and another protein (37,000 Da), which is less known (3). In addition, five FH allelic variants, located close to the FH gene in the RCA gene cluster (4), encode for FH related-proteins (FHR1 to FHR5). The FH protein is a 155,000 Da single polypeptide chain composed of twenty short consensus repeats (SCR) (5). Structural studies on the flexibility and size of FH suggest that FH SCR domains are bent back upon themselves. Moreover, the peptidic sequence and length of SCR domains influence the interaction between FH and multivalent ligands. FH (as FHL-1) is constitutively produced by the liver but other cells can produce FH (monocytes, keratinocytes, fibroblasts, oligodendrocytes or

Research paper thumbnail of Systemic administration of cationic phosphonolipids/DNA complexes and the relationship between formulation and lung transfection efficiency

Biochimica et Biophysica Acta (BBA) - Biomembranes, 2000

Performances of cationic lipid formulations for intravenous gene delivery to mouse lungs have bee... more Performances of cationic lipid formulations for intravenous gene delivery to mouse lungs have been previously reported. We report in this study that cationic phosphonolipids, when appropriately formulated, can be good synthetic vectors for gene delivery to lung after intravenous administration. One of our reagents, GLB43, was capable of mediating a 500-fold higher expression in the lungs of mice than could be obtained with free pDNA alone (P = 0.018). We demonstrate that the most important parameters for cationic phosphonolipid transfection activity after systemic administration are the chemical structure of the cationic phosphonolipid, the lipid to DNA charge ratio and the inclusion of co-lipid in the formulation. We report using a luciferase reporter gene that transfection activity in vivo 24 h after cationic phosphonolipid systemic administration could not be predicted from in vitro analysis. In contrast to in vitro studies, cationic phosphonolipids including the oleyl acyl chains (GLB43) were more effective than its analogue with the myristyl acyl chains (GLB73). Using pathological analysis of animal livers, we demonstrate that the toxicity level was correlated with the lipoplex formulation and the lipid to DNA ratio.

Research paper thumbnail of In Silico and In Vivo Studies of a Tumor-Penetrating and Interfering Peptide with Antitumoral Effect on Xenograft Models of Breast Cancer

Pharmaceutics, Apr 7, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Recombinant humanised anti-HER2/neu antibody (Herceptin®) induces cellular death of glioblastomas

British Journal of Cancer, 2004

Glioblastoma multiforme (GBM) remains the most devastating primary tumour in neuro-oncology. Targ... more Glioblastoma multiforme (GBM) remains the most devastating primary tumour in neuro-oncology. Targeting of the human epithelial receptor type 2 (HER2)-neu receptor by specific antibodies is a recent well-established therapy for breast tumours. Human epithelial receptor type 2/neu is a transmembrane tyrosine/kinase receptor that appears to be important for the regulation of cancer growth. Human epithelial receptor type 2/neu is not expressed in the adult central nervous system, but its expression increases with the degree of astrocytoma anaplasia. The specificity of HER2/neu for tumoral astrocytomas leads us to study in vitro treatment of GBM with anti-HER2/neu antibody. We used human GBM cell lines expressing HER2/neu (A172 express HER2/neu more than U251MG) or not (U87MG) and monoclonal humanised antibody against HER2/neu (Herceptin s). Human epithelial receptor type 2/neu expression was measured by immunohistochemistry and flow cytometry. Direct antibody effect, complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity were evaluated by different cytometric assays. We have shown, for the first time, the ability of anti-HER2/neu antibodies to induce apoptosis and cellular-dependent cytotoxicity of HER2/neu-expressing GBM cell lines. The results decreased from A172 to U251 and were negative for U87MG, in accordance with the decreasing density of HER2/neu receptors.

Research paper thumbnail of Increasing of HER2 membranar density in human glioblastoma U251MG cell line established in a new nude mice model

Journal of Neuro-Oncology, 2007

Research paper thumbnail of BAFF-modulated repopulation of B lymphocytes in the blood and salivary glands of RITUXIMAB-TREATED patients with Sjögren's syndrome

Arthritis & Rheumatism, 2007

Treatment with rituximab depletes B cells from the peripheral blood (PB) and salivary glands (SGs... more Treatment with rituximab depletes B cells from the peripheral blood (PB) and salivary glands (SGs) of patients with primary Sjögren&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s syndrome (SS). The purpose of this study was to track the repopulation of B cell subsets in PB as well as their subsequent homing into SGs in patients with primary SS treated with rituximab. A series of 4-color flow cytometry experiments delineated B cell subsets in 15 patients with primary SS. All were tested on days 8 and 15 of treatment. Nine of the patients were followed up monthly for 10 months, and the remaining 6 patients were followed up monthly for 24 months. Enzyme-linked immunosorbent assays were developed to measure serum levels of BAFF and rituximab. SGs were biopsied at the start of the study and 4 months after treatment in 15 patients, 12 months after treatment in 3 patients, and 24 months after treatment in 2 patients. Baseline serum levels of BAFF correlated inversely (r = -0.92, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 5 x 10(-4)) with the duration of B cell depletion: the higher the BAFF levels, the shorter the duration of B cell depletion. Four B cell subsets repopulated the PB: plasmablasts (CD19+, CD5-,IgD-,CD38++), transitional type 1 (T1) B cells (CD19+,CD5+,IgD+,CD38++), mature Bm2 cells (CD19+,CD5+/-,IgD+,CD38+/-), and memory B cells (CD19+,CD5-,IgD-,CD38-). Increased numbers of Bm2 cells and decreased memory B cells reappeared with time. Sequential SG biopsies revealed that B cells were absent in these glands for 12 months: they were detected 24 months after rituximab treatment. Memory and T1 B cells were the first B cells identified locally. The timing of B cell repopulation is modulated by BAFF and is followed by reconstitution of the preexisting abnormalities.

Research paper thumbnail of Is the c-Cbl Proto-Oncogene Involved in Chronic Lymphocytic Leukemia?

Annals of the New York Academy of Sciences, 2007

Chronic lymphocytic leukemia (CLL) is characterized by survival advantage and accumulation of CD5... more Chronic lymphocytic leukemia (CLL) is characterized by survival advantage and accumulation of CD5+ mature B lymphocytes. Expression of zeta-chain-associated protein-70 (ZAP-70), normally present in T lymphocytes or immature B cells, is associated with disease aggressiveness, as IgVH mutational status, and some proteins implicated in survival signal pathways are found to be constitutively activated in CLL cells. ZAP-70 signaling is regulated through molecular adaptors, such as the proto-oncogene product c-Casitas B lineage lymphoma (c-Cbl). The aim of this study was to determine the implication of this proto-oncogene product in CLL in survival signals. It appeared that expression of c-Cbl was increased in CLL and not correlated to that of B cell linker protein or ZAP-70. Furthermore, c-Cbl was significantly hypophosphorylated in progressive disease, so that hypophosphorylated form of c-Cbl (c-Cbl.P) along with ZAP-70, set a cutoff ratio distributing patients with stable situation below 1, and those with progressive disease equal or above 1. Given that phospholipase gamma 2 (PLC␥2) function is also influenced by c-Cbl hypophosphorylation, the ratio of PLC␥2 to c-Cbl.P was measured in CLL B cells and consistently found to be ≥ 1 in Binet stage B CLL patients, as opposed to stage A CLL patients. These findings invite analysis of the role of c-Cbl in CLL.