In the immature rat uterus, occupation of the androgen and estrogen receptor sties after injectio... more In the immature rat uterus, occupation of the androgen and estrogen receptor sties after injection of 5 alpha dihydrotestosterone (DHT = 17beta - hydroxy-5alpha-androstan-3-one) were compared to the biological responses induced by the androgen on protein synthesis. Injection of 100 mug DHT induced a maximal occupation of androgen receptor sites (RA) but was totally ineffective in translocating the estrogen receptor sites and in increasing general protein synthesis. Conversely, high doses of androgen (greater than or equal to 3 mg) translocated the estrogen receptor (RE) and stimulated general protein synthesis. In addition, these high doses induced a specific uterine protein undistinguishable from that induced by estradiol treatment (IP). These results strongly suggest that the uterotrophic response of the uterus to androgen is correlated with the nuclear transreceptor which is present in much smaller amounts.
Los ecosistemas marinos costeros desempeñan un importante papel ecológico tanto por su implicació... more Los ecosistemas marinos costeros desempeñan un importante papel ecológico tanto por su implicación en la productividad marina como por la biodiversidad que albergan, así como por los bienes y servicios que nos proporcionan. Pero muestran una elevada vulnerabilidad frente a perturbaciones tanto de origen natural como causadas por el hombre, y muchos de ellos están en declive a escala global. Los hábitats cercanos a la costa y en particular las comunidades de la zona infralitoral están especialmente afectados por las actividades humanas debido a su proximidad y las infraestructuras que conllevan.
ABSTRACT Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Co... more ABSTRACT Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-AC04-94-AL85000. Approved for public release; further dissemination unlimited.
Background: Although several mathematical models have been proposed to assess the risk:benefit of... more Background: Although several mathematical models have been proposed to assess the risk:benefit of drugs in one measure, their use in practice has been rather limited. Our objective was to design a simple, easily applicable model. In this respect, measuring the proportion of patients who respond favorably to treatment without being affected by adverse drug reactions (ADR) could be a suitable endpoint. However, remarkably few published clinical trials report the data required to calculate this proportion. As an approach to the problem, we calculated the expected proportion of this type of patients.
Cathepsin D (CathD) is overexpressed and secreted by several solid tumors and stimulates their gr... more Cathepsin D (CathD) is overexpressed and secreted by several solid tumors and stimulates their growth, the mechanism of which is still not understood. In this context, the pepstatin bioconjugate JMV4463 [Ac-arg-O2 Oc-(Val)3 -Sta-Ala-Sta-(AMPA)4 -NH2 ; O2 Oc=8-amino-3,6-dioxaoctanoyl, Sta=statine, AMPA=ortho-aminomethylphenylacetyl], containing a new kind of cell-penetrating vector, was previously shown to exhibit potent antiproliferative effects in vitro and to delay the onset of tumors in vivo. In this study, we performed a structure-activity relationship analysis to evaluate the significance of the inhibitor and vector moieties of JMV4463. By modifying both statine residues of pepstatin we found that the antiproliferative activity is correlated with CathD inhibition, supporting a major role of the catalytic activity of intracellular CathD in cancer cell proliferation. Replacing the vector composed of four AMPA units with other vectors was found to abolish cytotoxicity, although al...
The synthesis of mesoporous silica nanoparticles bearing organic functionalities is strained by t... more The synthesis of mesoporous silica nanoparticles bearing organic functionalities is strained by the careful adjustment of the reaction parameters, as the incorporation of functional and/or voluminous organosilanes during the sol-gel synthesis strongly affects the final structure of the nanoparticles. In this paper we describe the design of new clickable mesoporous silica nanoparticles as spheres or rods, synthesized by the co-condensation of TEOS with two clickable organosilanes (bearing alkyne and azide groups) and readily multi-functionalizable by CuAAC click chemistry. We show that controlled loadings of clickable functions can be homogeneously distributed within the MSN, allowing us to efficiently click-graft various pairs of functionalities while preserving the texture and morphology of the particles. The homogeneous distribution of the grafted functionalities was probed by FRET experiments between two anchored fluorophores. Moreover, a communication by proton transfer between two functions was demonstrated by constructing a light-actuated nanomachine that works through a proton transfer between a photoacid generator and a pH-sensitive supramolecular nanogate. The activation of the nanomachine enabled the successful release of rhodamine B in buffered solutions and the delivery of doxorubicin in breast cancer cells (MCF-7) upon blue irradiation.
To understand the mechanisms of tumor invasion and metastasis, model systems are required that is... more To understand the mechanisms of tumor invasion and metastasis, model systems are required that isolate the individual steps of these complicated, multifaceted processes. We propose a new procedure to identify genes involved in cell invasion and/or motility that features the combined advantages of transient gene transfection and Matrigel invasion assays. Cancer cells were transiently cotransfected with two vectors expressing the gene of interest and luciferase, as a marker of transfected cells, and then assayed for Matrigel invasion. Luciferase cotransfection appeared to be a sensitive semiquantitative assay for transfected cells and was maximal throughout the invasion assay. The proposed transfection procedure, using calcium phosphate precipitation, did not affect cell invasiveness and allowed cellular coexpression of both genes. When applying this method, we found that transient expression of the unliganded and liganded human estrogen receptor alpha prevented invasiveness of MDA-MB-231 breast cancer cells. In conclusion, we propose rapid and versatile in vitro procedure for studying the effects of individual cloned genes on cellular processes, such as invasion and motility.
The Mr 52,000 glycoprotein is regulated by estrogen and released by breast cancer cells in cultur... more The Mr 52,000 glycoprotein is regulated by estrogen and released by breast cancer cells in culture (B. Westley and H. Rochefort, Cell, 20: 352-362, 1980). This rare protein was partially purified from 25 liters of medium conditioned by MCF7 cells and injected into Biozzi's selected mice. The spleen lym phocytes of one immunized mouse was fused with the murine myeloma
The synthesis of Mesoporous Silica Nanoparticles (MSN) covalently encapsulating fluoresceine or a... more The synthesis of Mesoporous Silica Nanoparticles (MSN) covalently encapsulating fluoresceine or a photosensitizer, functionalized with galactose on the surface is described. Confocal microscopy experiments demonstrated that the uptake of galactose-functionalized MSN by colorectal cancer cells was mediated by galactose receptors leading to the accumulation of the nanoparticles in the endosomal and lysosomal compartments. The MSN functionalized with a photosensitizer and galactose were loaded with the anticancer drug camptothecin. Those MSN combining drug delivery and photodynamic therapy were tested on three cancer cell lines and showed a dramatic enhancement of cancer cell death compared to separate treatments. (A. Morère), [email protected] (M. Garcia), [email protected] (J.-O. Durand).
Mesoporous silica nanoparticles (MSNPs) are functionalized with molecular-recognition sites by an... more Mesoporous silica nanoparticles (MSNPs) are functionalized with molecular-recognition sites by anchoring a triazine or uracil fragment on the surface. After loading these MSNPs with dyes (propidium iodide or rhodamine B) or with a drug (camptothecin, CPT) they are capped by the complementary fragments, uracil and adenine, respectively, linked to the bulky cyclodextrin ring. These MSNPs are pH-sensitive and indeed, the dye release was observed at acidic pH by continuously monitored fluorescence spectroscopy studies. On the other hand, no dye leakage occurred at neutral pH, hence meeting the non-premature requirement to minimize side effects. In vitro studies were performed and confocal microscopy images demonstrate the internalization of the MSNPs and also dye release in the cells. To investigate the drug-delivery performance, the cytotoxicity of CPT-loaded nanoparticles was tested and cell death was observed. A remarkably lower amount of loaded CPT in the MSNPs (more than 40 times less) proved to be as efficient as free CPT. These results not only demonstrate the drug release after pore opening under lysosomal pH, but they also show the potential use of these MSNPs to significantly decrease the amount of the administered drug.
We studied the phagocytic-like capacity of human CD34+ stromal cells/telocytes (TCs). For this, w... more We studied the phagocytic-like capacity of human CD34+ stromal cells/telocytes (TCs). For this, we examined segments of the colon after injection of India ink to help surgeons localize lesions identified at endoscopy. Our results demonstrate that CD34+ TCs have endocytic properties (phagocytic-like TCs: phTCs), with the capacity to uptake and store India ink particles. phTCs conserve the characteristics of TCs (long, thin, bipolar or multipolar, moniliform cytoplasmic processes/telopodes, with linear distribution of the pigment) and maintain their typical distribution. Likewise, they are easily distinguished from pigment-loaded macrophages (CD68+ macrophages, with oval morphology and coarse granules of pigment clustered in their cytoplasm). A few c-kit/CD117+ interstitial cells of Cajal also incorporate pigment and may conserve the phagocytic-like property of their probable TC precursors. CD34+ stromal cells in other locations (skin and periodontal tissues) also have the phagocytic-like capacity to uptake and store pigments (hemosiderin, some components of dental amalgam and melanin). This suggests a function of TCs in general, which may be related to the transfer of macromolecules in these cells. Our ultrastructural observation of melanin-storing stromal cells with characteristics of TCs (telopodes with dichotomous branching pattern) favours this possibility. In conclusion, intestinal TCs have a phagocytic-like property, a function that may be generalized to TCs in other locations. This function (the ability to internalize small particles), together with the capacity of these cells to release extracellular vesicles with macromolecules, could close the cellular bidirectional cooperative circle of informative exchange and intercellular interactions.
In the immature rat uterus, occupation of the androgen and estrogen receptor sties after injectio... more In the immature rat uterus, occupation of the androgen and estrogen receptor sties after injection of 5 alpha dihydrotestosterone (DHT = 17beta - hydroxy-5alpha-androstan-3-one) were compared to the biological responses induced by the androgen on protein synthesis. Injection of 100 mug DHT induced a maximal occupation of androgen receptor sites (RA) but was totally ineffective in translocating the estrogen receptor sites and in increasing general protein synthesis. Conversely, high doses of androgen (greater than or equal to 3 mg) translocated the estrogen receptor (RE) and stimulated general protein synthesis. In addition, these high doses induced a specific uterine protein undistinguishable from that induced by estradiol treatment (IP). These results strongly suggest that the uterotrophic response of the uterus to androgen is correlated with the nuclear transreceptor which is present in much smaller amounts.
Los ecosistemas marinos costeros desempeñan un importante papel ecológico tanto por su implicació... more Los ecosistemas marinos costeros desempeñan un importante papel ecológico tanto por su implicación en la productividad marina como por la biodiversidad que albergan, así como por los bienes y servicios que nos proporcionan. Pero muestran una elevada vulnerabilidad frente a perturbaciones tanto de origen natural como causadas por el hombre, y muchos de ellos están en declive a escala global. Los hábitats cercanos a la costa y en particular las comunidades de la zona infralitoral están especialmente afectados por las actividades humanas debido a su proximidad y las infraestructuras que conllevan.
ABSTRACT Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Co... more ABSTRACT Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-AC04-94-AL85000. Approved for public release; further dissemination unlimited.
Background: Although several mathematical models have been proposed to assess the risk:benefit of... more Background: Although several mathematical models have been proposed to assess the risk:benefit of drugs in one measure, their use in practice has been rather limited. Our objective was to design a simple, easily applicable model. In this respect, measuring the proportion of patients who respond favorably to treatment without being affected by adverse drug reactions (ADR) could be a suitable endpoint. However, remarkably few published clinical trials report the data required to calculate this proportion. As an approach to the problem, we calculated the expected proportion of this type of patients.
Cathepsin D (CathD) is overexpressed and secreted by several solid tumors and stimulates their gr... more Cathepsin D (CathD) is overexpressed and secreted by several solid tumors and stimulates their growth, the mechanism of which is still not understood. In this context, the pepstatin bioconjugate JMV4463 [Ac-arg-O2 Oc-(Val)3 -Sta-Ala-Sta-(AMPA)4 -NH2 ; O2 Oc=8-amino-3,6-dioxaoctanoyl, Sta=statine, AMPA=ortho-aminomethylphenylacetyl], containing a new kind of cell-penetrating vector, was previously shown to exhibit potent antiproliferative effects in vitro and to delay the onset of tumors in vivo. In this study, we performed a structure-activity relationship analysis to evaluate the significance of the inhibitor and vector moieties of JMV4463. By modifying both statine residues of pepstatin we found that the antiproliferative activity is correlated with CathD inhibition, supporting a major role of the catalytic activity of intracellular CathD in cancer cell proliferation. Replacing the vector composed of four AMPA units with other vectors was found to abolish cytotoxicity, although al...
The synthesis of mesoporous silica nanoparticles bearing organic functionalities is strained by t... more The synthesis of mesoporous silica nanoparticles bearing organic functionalities is strained by the careful adjustment of the reaction parameters, as the incorporation of functional and/or voluminous organosilanes during the sol-gel synthesis strongly affects the final structure of the nanoparticles. In this paper we describe the design of new clickable mesoporous silica nanoparticles as spheres or rods, synthesized by the co-condensation of TEOS with two clickable organosilanes (bearing alkyne and azide groups) and readily multi-functionalizable by CuAAC click chemistry. We show that controlled loadings of clickable functions can be homogeneously distributed within the MSN, allowing us to efficiently click-graft various pairs of functionalities while preserving the texture and morphology of the particles. The homogeneous distribution of the grafted functionalities was probed by FRET experiments between two anchored fluorophores. Moreover, a communication by proton transfer between two functions was demonstrated by constructing a light-actuated nanomachine that works through a proton transfer between a photoacid generator and a pH-sensitive supramolecular nanogate. The activation of the nanomachine enabled the successful release of rhodamine B in buffered solutions and the delivery of doxorubicin in breast cancer cells (MCF-7) upon blue irradiation.
To understand the mechanisms of tumor invasion and metastasis, model systems are required that is... more To understand the mechanisms of tumor invasion and metastasis, model systems are required that isolate the individual steps of these complicated, multifaceted processes. We propose a new procedure to identify genes involved in cell invasion and/or motility that features the combined advantages of transient gene transfection and Matrigel invasion assays. Cancer cells were transiently cotransfected with two vectors expressing the gene of interest and luciferase, as a marker of transfected cells, and then assayed for Matrigel invasion. Luciferase cotransfection appeared to be a sensitive semiquantitative assay for transfected cells and was maximal throughout the invasion assay. The proposed transfection procedure, using calcium phosphate precipitation, did not affect cell invasiveness and allowed cellular coexpression of both genes. When applying this method, we found that transient expression of the unliganded and liganded human estrogen receptor alpha prevented invasiveness of MDA-MB-231 breast cancer cells. In conclusion, we propose rapid and versatile in vitro procedure for studying the effects of individual cloned genes on cellular processes, such as invasion and motility.
The Mr 52,000 glycoprotein is regulated by estrogen and released by breast cancer cells in cultur... more The Mr 52,000 glycoprotein is regulated by estrogen and released by breast cancer cells in culture (B. Westley and H. Rochefort, Cell, 20: 352-362, 1980). This rare protein was partially purified from 25 liters of medium conditioned by MCF7 cells and injected into Biozzi's selected mice. The spleen lym phocytes of one immunized mouse was fused with the murine myeloma
The synthesis of Mesoporous Silica Nanoparticles (MSN) covalently encapsulating fluoresceine or a... more The synthesis of Mesoporous Silica Nanoparticles (MSN) covalently encapsulating fluoresceine or a photosensitizer, functionalized with galactose on the surface is described. Confocal microscopy experiments demonstrated that the uptake of galactose-functionalized MSN by colorectal cancer cells was mediated by galactose receptors leading to the accumulation of the nanoparticles in the endosomal and lysosomal compartments. The MSN functionalized with a photosensitizer and galactose were loaded with the anticancer drug camptothecin. Those MSN combining drug delivery and photodynamic therapy were tested on three cancer cell lines and showed a dramatic enhancement of cancer cell death compared to separate treatments. (A. Morère), [email protected] (M. Garcia), [email protected] (J.-O. Durand).
Mesoporous silica nanoparticles (MSNPs) are functionalized with molecular-recognition sites by an... more Mesoporous silica nanoparticles (MSNPs) are functionalized with molecular-recognition sites by anchoring a triazine or uracil fragment on the surface. After loading these MSNPs with dyes (propidium iodide or rhodamine B) or with a drug (camptothecin, CPT) they are capped by the complementary fragments, uracil and adenine, respectively, linked to the bulky cyclodextrin ring. These MSNPs are pH-sensitive and indeed, the dye release was observed at acidic pH by continuously monitored fluorescence spectroscopy studies. On the other hand, no dye leakage occurred at neutral pH, hence meeting the non-premature requirement to minimize side effects. In vitro studies were performed and confocal microscopy images demonstrate the internalization of the MSNPs and also dye release in the cells. To investigate the drug-delivery performance, the cytotoxicity of CPT-loaded nanoparticles was tested and cell death was observed. A remarkably lower amount of loaded CPT in the MSNPs (more than 40 times less) proved to be as efficient as free CPT. These results not only demonstrate the drug release after pore opening under lysosomal pH, but they also show the potential use of these MSNPs to significantly decrease the amount of the administered drug.
We studied the phagocytic-like capacity of human CD34+ stromal cells/telocytes (TCs). For this, w... more We studied the phagocytic-like capacity of human CD34+ stromal cells/telocytes (TCs). For this, we examined segments of the colon after injection of India ink to help surgeons localize lesions identified at endoscopy. Our results demonstrate that CD34+ TCs have endocytic properties (phagocytic-like TCs: phTCs), with the capacity to uptake and store India ink particles. phTCs conserve the characteristics of TCs (long, thin, bipolar or multipolar, moniliform cytoplasmic processes/telopodes, with linear distribution of the pigment) and maintain their typical distribution. Likewise, they are easily distinguished from pigment-loaded macrophages (CD68+ macrophages, with oval morphology and coarse granules of pigment clustered in their cytoplasm). A few c-kit/CD117+ interstitial cells of Cajal also incorporate pigment and may conserve the phagocytic-like property of their probable TC precursors. CD34+ stromal cells in other locations (skin and periodontal tissues) also have the phagocytic-like capacity to uptake and store pigments (hemosiderin, some components of dental amalgam and melanin). This suggests a function of TCs in general, which may be related to the transfer of macromolecules in these cells. Our ultrastructural observation of melanin-storing stromal cells with characteristics of TCs (telopodes with dichotomous branching pattern) favours this possibility. In conclusion, intestinal TCs have a phagocytic-like property, a function that may be generalized to TCs in other locations. This function (the ability to internalize small particles), together with the capacity of these cells to release extracellular vesicles with macromolecules, could close the cellular bidirectional cooperative circle of informative exchange and intercellular interactions.
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Papers by Marcel Garcia