Marjorie Fanjul

University of Toulouse, Tolosa de Llenguadoc, Midi-Pyrénées, France

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Publications (33)146.14 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Background & aims: The KRAS gene is mutated in most pancreatic ductal adenocarcinomas (PDAC). Expression of this KRAS oncoprotein in mice is sufficient to initiate carcinogenesis but not progression to cancer. Activation of phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) is required for KRAS for induction and maintenance of PDAC in mice. The somatostatin receptor subtype 2 (sst2) inhibits PI3K, but sst2 expression is lost during the development of human PDAC. We investigated the effects of sst2 loss during KRAS-induced PDAC development in mice. Methods: We analyzed tumor growth in mice that expressed the oncogenic form of KRAS (KRAS(G12D)) in pancreatic precursor cells, as well as sst2+/- and sst2-/-, and in crossed KRAS(G12D);sst2+/- and KRAS(G12D);sst2-/- mice. Pancreatic tissues and acini were collected and assessed by histologic, immunoblot, immunohistochemical, and reverse-transcription polymerase chain reaction analyses. We also compared protein levels in paraffin-embedded PDAC samples from patients vs heathy pancreatic tissues from individuals without pancreatic cancer. Results: In sst2+/- mice, PI3K was activated and signaled via AKT (PKB; protein kinase B); when these mice were crossed with KRAS(G12D) mice, premalignant lesions, tumors, and lymph node metastases developed more rapidly than in KRAS(G12D) mice. In crossed KRAS(G12D);sst2+/- mice, activation of PI3K signaling via AKT resulted in activation of nuclear factor-κB (NF-κB), which increased KRAS activity and its downstream pathways, promoting initiation and progression of neoplastic lesions. We found this activation loop to be mediated by PI3K-induced production of the chemokine CXCL16. Administration of a CXCL16-neutralizing antibody to KRAS(G12D) mice reduced activation of PI3K signaling to AKT and NF-κB, blocking carcinogenesis. Levels of CXCL16 and its receptor CXCR6 were significantly higher in PDAC tissues and surrounding acini than in healthy pancreatic tissues from mice or human beings. In addition, expression of sst2 was progressively lost, involving increased PI3K activity, in mouse lesions that expressed KRAS(G12D) and progressed to PDAC. Conclusions: Based on analyses of mice, loss of sst2 from pancreatic tissues activates PI3K signaling via AKT, leading to activation of NF-κB, amplification of oncogenic KRAS signaling, increased expression of CXCL16, and pancreatic tumor formation. CXCL16 might be a therapeutic target for PDAC.
    Gastroenterology 02/2015; 148(7). DOI:10.1053/j.gastro.2015.02.009 · 16.72 Impact Factor
  • Cancer Research 04/2014; 72(14 Supplement):B60-B60. DOI:10.1158/1538-7445.PANCA2012-B60 · 9.33 Impact Factor
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    ABSTRACT: Given the failure of chemo- and biotherapies to fight advanced pancreatic cancer, one major challenge is to identify critical events that initiate invasion. One priming step in epithelia carcinogenesis is the disruption of epithelial cell anchorage to the basement membrane which can be provided by hemidesmosomes (HDs). However, the existence of HDs in pancreatic ductal epithelium and their role in carcinogenesis remain unexplored. HDs have been explored in normal and cancer pancreatic cells, and patient samples. Unique cancer cell models where HD assembly can be pharmacologically manipulated by somatostatin/sst2 signaling have been then used to investigate the role and molecular mechanisms of dynamic HD during pancreatic carcinogenesis. We surprisingly report the presence of mature type-1 HDs comprising the integrin α6β4 and bullous pemphigoid antigen BP180 in the human pancreatic ductal epithelium. Importantly, HDs are shown to disassemble during pancreatic carcinogenesis. HD breakdown requires phosphoinositide 3-kinase (PI3K)-dependent induction of the matrix-metalloprotease MMP-9, which cleaves BP180. Consequently, integrin α6β4 delocalizes to the cell-leading edges where it paradoxically promotes cell migration and invasion through S100A4 activation. As S100A4 in turn stimulates MMP-9 expression, a vicious cycle maintains BP180 cleavage. Inactivation of this PI3K-MMP-9-S100A4 signaling loop conversely blocks BP180 cleavage, induces HD reassembly and inhibits cell invasion. We conclude that mature type-1 HDs are critical anchoring structures for the pancreatic ductal epithelium whose disruption, upon PI3K activation during carcinogenesis, provokes pancreatic cancer cell migration and invasion.Oncogene advance online publication, 29 April 2013; doi:10.1038/onc.2013.146.
    Oncogene 04/2013; 33(15). DOI:10.1038/onc.2013.146 · 8.46 Impact Factor
  • Cancer Research 01/2011; 70(8 Supplement):5181-5181. DOI:10.1158/1538-7445.AM10-5181 · 9.33 Impact Factor
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    ABSTRACT: It has been shown that adult pancreatic ductal cells can dedifferentiate and act as pancreatic progenitors. Dedifferentiation of epithelial cells is often associated with the epithelial-mesenchymal transition (EMT). In this study, we investigated the occurrence of EMT in adult human exocrine pancreatic cells both in vitro and in vivo. Cells of exocrine fraction isolated from the pancreas of brain-dead donors were first cultured in suspension for eight days. This led to the formation of spheroids, composed of a principal population of cells with duct-like phenotype. When cultivated in tissue culture-treated flasks, spheroid cells exhibited a proliferative capacity and coexpressed epithelial (cytokeratin7 and cytokeratin19) and mesenchymal (vimentin and alpha-smooth muscle actin) markers as well as marker of progenitor pancreatic cells (pancreatic duodenal homeobox factor-1) and surface markers of mesenchymal stem cells. The switch from E-cadherin to N-cadherin associated with Snail1 expression suggested that these cells underwent EMT. In addition, we showed coexpression of epithelial and mesenchymal markers in ductal cells of one normal adult pancreas and three type 2 diabetic pancreases. Some of the vimentin-positive cells were found to coexpress glucagon or amylase. These results point to the occurrence of EMT, which may take place on dedifferentiation of ductal cells during the regeneration or renewal of human pancreatic tissues.
    Journal of Histochemistry and Cytochemistry 09/2010; 58(9):807-23. DOI:10.1369/jhc.2010.955807 · 1.96 Impact Factor
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    Anne Probst · Hongyu Liu · Marjorie Fanjul · Bohan Liao · Etienne Hollande
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    ABSTRACT: Vicia faba L. seeds were grown in a pot experiment on soil, mine tailings, and a mixture of both to mimic field situations in cultivated contaminated areas near mining sites. Metals in the substrates and their translocation in root, stem and leaf tissues were investigated, including morphological responses of plants growing on mine tailings. Metal concentration – and generally bioaccumulation – was in the order: roots > leaves > stems, except Pb and Cd. Translocation was most significant for Zn and Cd, but limited for Pb. Metal concentration in root and leaf was not proportional to that in the substrates, unexpectedly the minimum being observed in the mixed substrate whilst plant growth was retarded by 20% (38% on tailings). Calcium, pH, organic matter and phosphorus were the main influencing factors for metal translocation. The ultrastructure of V. faba L. cells changed a lot in the mine tailings group: root cell walls were thickened with electron dense Pb, Zn and C particles; in chloroplasts, the number of plastoglobuli increased, whereas the thylakoids were swollen and their number decreased in grana. Finally, needle-shaped crystalline concretions made of Ca and P, with Zn content, were formed in the apoplast of the plants. The stratagems of V. faba L. undergoing high concentrations of toxic metals in carbonate substrate, suggest root cell wall thickening to decrease uptake of toxic metals, a possible control of metal transport from roots to leaves by synthesizing phytochelators–toxic metal complexes, and finally a control of exceeded Ca and metal concentration in leaves by crystal P formation as ultimate response to stress defense. The geochemical factors influencing metal availability, guaranty a reduction of metal content in plant growing on mixed tailing/soil substrate as far as carbonate are not completely dissolved.
    Environmental and Experimental Botany 05/2009; 66(2-66):297-308. DOI:10.1016/j.envexpbot.2009.02.003 · 3.36 Impact Factor
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    Marjorie Fanjul · Laetitia Alvarez · Etienne Hollande
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    ABSTRACT: The high intraluminal concentrations of HCO(3)(-) in the human pancreatic ducts have suggested the existence of a membrane protein supplying the Cl(-)/HCO(3)(-) exchanger. Membrane-bound carbonic anhydrase IV (CA IV) is one of the potential candidates for this protein. The difficulties in isolating human pancreatic ducts have led the authors to study the molecular mechanisms of HCO(3)(-) secretion in cancerous cell lines. In this work, we have characterized the CA IV expressed in Capan-1 cells. A 35-kDa CA IV was detected in cell homogenates and purified plasma membranes. Treatment of purified plasma membranes with phosphatidylinositol-phospholipase-C indicated that this CA IV was not anchored by a glycosylphosphatidylinositol (GPI). In contrast, its detection on purified plasma membranes by an antibody specifically directed against the carboxyl terminus of human immature GPI-anchored CA IV indicated that it was anchored by a C-terminal hydrophobic segment. Immunoelectron microscopy and double-labeling immunofluorescence revealed that this CA IV was present on apical plasma membranes, and in the rough endoplasmic reticulum, the endoplasmic reticulum-Golgi intermediate compartment, the Golgi complex, and secretory granules, suggesting its transport via the classical biosynthesis/secretory pathway. The expression in Capan-1 cells of a 35-kDa CA IV anchored in the apical plasma membrane through a hydrophobic segment, as is the case in the healthy human pancreas, should make the study of its role in pancreatic HCO(3)(-) secretion easier.
    Journal of Histochemistry and Cytochemistry 09/2007; 55(8):783-94. DOI:10.1369/jhc.6A7112.2007 · 1.96 Impact Factor
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    ABSTRACT: Phosphatidylinositol 3-kinase (PI3K) regulates many cellular functions including growth and survival, and its excessive activation is a hallmark of cancer. Somatostatin, acting through its G protein-coupled receptor (GPCR) sst2, has potent proapoptotic and anti-invasive activities on normal and cancer cells. Here, we report a novel mechanism for inhibiting PI3K activity. Somatostatin, acting through sst2, inhibits PI3K activity by disrupting a pre-existing complex comprising the sst2 receptor and the p85 PI3K regulatory subunit. Surface plasmon resonance and molecular modeling identified the phosphorylated-Y71 residue of a p85-binding pYXXM motif in the first sst2 intracellular loop, and p85 COOH-terminal SH2 as direct interacting domains. Somatostatin-mediated dissociation of this complex as well as p85 tyrosine dephosphorylation correlates with sst2 tyrosine dephosphorylation on the Y71 residue. Mutating sst2-Y71 disabled sst2 to interact with p85 and somatostatin to inhibit PI3K, consequently abrogating sst2's ability to suppress cell survival and tumor growth. These results provide the first demonstration of a physical interaction between a GPCR and p85, revealing a novel mechanism for negative regulation by ligand-activated GPCR of PI3K-dependent survival pathways, which may be an important molecular target for antineoplastic therapy.
    The EMBO Journal 10/2006; 25(17):3943-54. DOI:10.1038/sj.emboj.7601279 · 10.43 Impact Factor
  • H Lahlou · M Fanjul · L Pradayrol · C Susini · S Pyronnet
    Gastroentérologie Clinique et Biologique 01/2006; 30(1):72-72. DOI:10.1016/S0399-8320(06)73083-4 · 1.14 Impact Factor
  • Gastroentérologie Clinique et Biologique 01/2006; 30(1):77-77. DOI:10.1016/S0399-8320(06)73091-3 · 1.14 Impact Factor
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    ABSTRACT: The structural integrity of the Golgi complex is essential to its functions in the maturation, sorting, and transport of plasma membrane proteins. Previously, we demonstrated that in pancreatic duct CFPAC-1 cells, which express DeltaF508 CFTR (cystic fibrosis transmembrane conductance regulator), the intracellular trafficking of carbonic anhydrase IV (CA IV), a membrane protein involved in HCO(3)(-) secretion, was impaired. To determine whether these abnormalities were related to changes in the Golgi complex, we examined the ultrastructure and distribution of Golgi compartments with regard to the microtubule cytoskeleton in CFPAC-1 cells transfected or not with the wild-type CFTR. Ultrastructural and immunocytochemical analysis showed that in polarized CFPAC-1 cells, Golgi stacks were disconnected from one another and scattered throughout the cytoplasm. The colocalization of CA IV with markers of Golgi compartments indicated the ability of stacks to transfer this enzyme. This Golgi dispersal was associated with abnormal microtubule distribution and multiplicity of the microtubule-organizing centers (MTOCs). In reverted cells, the normalization of Golgi structure, microtubule distribution, and MTOC number was observed. These observations suggest that the entire biosynthetic/secretory pathway is disrupted in CFPAC-1 cells, which might explain the abnormal intracellular transport of CA IV. Taken together, these results point to the fact that the expression of DeltaF508 CFTR affects the integrity of the secretory pathway.
    Journal of Histochemistry and Cytochemistry 01/2006; 53(12):1539-52. DOI:10.1369/jhc.4A6587.2005 · 1.96 Impact Factor
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    ABSTRACT: Gap junctions are composed of connexins and are critical for the maintenance of the differentiated state. Consistently, connexin expression is impaired in most cancer cells, and forced expression of connexins following cDNA transfection reverses the tumor phenotype. We have found that the restoration of density inhibition of human pancreatic cancer cells by the antiproliferative somatostatin receptor 2 (sst2) is due to overexpression of endogenous connexins Cx26 and Cx43 and consequent formation of functional gap junctions. Immunoblotting along with protein metabolic labeling and mRNA monitoring revealed that connexin expression is enhanced at the level of translation but is not sensitive to the inhibition of cap-dependent translation initiation. Furthermore, we identified a new internal ribosome entry site (IRES) in the Cx26 mRNA. The activity of Cx26 IRES and that of the previously described Cx43 IRES are enhanced in density-inhibited cells. These data indicate that the restoration of functional gap junctions is likely a critical event in the antiproliferative action of the sst2 receptor. We further suggest that the existence of IRESes in connexin mRNAs permits connexin expression in density-inhibited or differentiated cells, where cap-dependent translation is generally reduced.
    Molecular and Cellular Biology 06/2005; 25(10):4034-45. DOI:10.1128/MCB.25.10.4034-4045.2005 · 4.78 Impact Factor
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    ABSTRACT: Alveolar type II pneumocytes are thought to be progenitor cells capable of self-renewal and differentiation into type I pneumocytes. Nevertheless, the existence of an alveolar stem cell has been postulated. In lungs from patients with cystic fibrosis, the alveolar epithelium is damaged with ulceration and subsequent regeneration. We characterized alveolar modifications histologically and immunohistochemically in the pulmonary tissue of a patient homozygous for the DeltaF508 mutation. Alveoli were of variable size and surrounded by an inflammatory infiltrate. They were lined by a continuous layer of cuboidal cells with very weak proliferative activity. These cells resembled type II pneumocytes. They expressed thyroid transcription factor-1, cystic fibrosis transmembrane conductance regulator, cytokeratin 7 and contained lamellar bodies. Weak expression of cytokeratin 5 considered to be a marker of progenitor cells of the bronchial and bronchiolar epithelium was detected. Explantation of this alveolar epithelium produced primary cultures and subcultures of epithelial cells that had acquired proliferative properties showing signs of dedifferentiation with a loss of lamellar bodies and a lack of expression of thyroid transcription factor-1. Persistence of the expression of cytokeratin 7 and a strong expression of cytokeratin 5 were observed. The culture conditions were thought to have circumvented the inhibition of proliferation observed in vivo due to the inflammatory peri-alveolar environment. They thus favored the multiplication of a population of cells co-expressing cytokeratin 5 and certain characteristics of type II pneumocytes. The presence of these cells of intermediate phenotype is indicative of the existence of immature precursors for type II pneumocytes.
    Biology of the Cell 09/2004; 96(6):429-41. DOI:10.1016/j.biolcel.2004.04.005 · 3.51 Impact Factor
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    ABSTRACT: The high concentration of HCO(3)(-) ions (150 mM) in the human pancreatic ducts raises the question of the membrane proteins responsible for their secretion in addition to the Cl(-)/HCO(3)(-) exchanger. In this study, we investigated the expression of carbonic anhydrase IV (CA IV), a possible candidate. Experiments were carried out on specimens of normal human pancreas obtained from brain-dead donors ( n=9) as well as on isolated human ductal cells. Two antibodies were generated: CA IV NH(2) antibody directed against the NH(2) terminal of human glycosyl phosphatidylinositol (GPI)-anchored CA IV and CA IV COOH antibody directed against the COOH terminal of the same protein before its association with a GPI in the rough endoplasmic reticulum. A 35-kDa CA IV was detected in the homogenates of human pancreas. Immunocytochemistry demonstrated the expression of CA IV in centroacinar cells and in intercalated, intralobular, and interlobular ductal cells. The immunoreactivity observed with the CA IV COOH antibody was mainly localized on luminal membranes of ductal cells. Treatment of purified plasma membranes with phosphatidylinositol-phospholipase C indicated that the CA IV expressed in pancreatic ducts was not GPI-anchored. Its detection in the same extracts by the CA IV COOH antibody indicated that it was anchored by a hydrophobic segment at the carboxy terminal. Taken together, these results suggest that normal human pancreatic ductal cells express a 35-kDa CA IV anchored in their luminal plasma membrane by a hydrophobic segment of the COOH terminus. In view of its localization and its mode of anchorage in luminal plasma membranes, this CA IV may participate in the maintenance of luminal pH.
    Histochemie 03/2004; 121(2):91-9. DOI:10.1007/s00418-003-0616-2 · 3.05 Impact Factor
  • A Doat · M Fanjul · F Pellé · E Hollande · A Lebugle
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    ABSTRACT: The authors prepared at low temperatures (37 degrees C) a novel inorganic bioprobe. It consisted of mineral nanoparticles of apatitic tricalcium phosphate doped with europium, of size, structure and composition close to those of the mineral part of calcified tissues. In contrast to organic probes which degrade rapidly (photobleaching), the red luminescence of the new probe is photostable. Moreover, this luminescence can be obtained under visible irradiation, which makes it suitable for prolonged examination of live cells. Human pancreatic epithelial cells in culture were incubated with these particles and their internalization was observed by laser scanning confocal microscopy. Transmission electron microscopy and electron microdiffraction analysis confirmed that the particles were internalized retaining their original apatitic structure. This probe may thus be of value for biovectorization.
    Biomaterials 09/2003; 24(19):3365-71. DOI:10.1016/S0142-9612(03)00169-8 · 8.56 Impact Factor
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    ABSTRACT: Human pancreatic duct cells secrete HCO3- ions mediated by a Cl-/HCO3- exchanger and a HCO3- channel that may be a carbonic anhydrase IV (CA IV) in a channel-like conformation. This secretion is regulated by CFTR (Cystic Fibrosis Transmembrane conductance Regulator). In CF cells homozygous for the deltaF508 mutation, the defect in targeting of CFTR to plasma membranes leads to a disruption in the secretion of Cl- and HCO3 ions along with a defective targeting of other proteins. In this study, we analyzed the targeting of membrane CA IV in the human pancreatic duct cell line CFPAC-1, which expresses a deltaF508 CFTR, and in the same cells transfected with the wild-type CFTR (CFPAC-PLJ-CFTR6) or with the vector alone (CFPAC-PLJ6). The experiments were conducted on cells in the stationary phase the polarized state of which was checked by the distribution of occludin and actin. We show that both cell lines express a 35-kDa CA IV at comparable levels. Analysis of fractions of plasma membranes purified on a Percoll gradient evidenced lower levels of CA IV (8-fold) in the CFPAC-1 than in the CFPAC-PLJ-CFTR6 cells. Quantitative analyses showed that 6- to 10-fold fewer cells in the CFPAC-1 cell line exhibited membrane CA IV-immunoreactivity than in the CFPAC-PLJ-CFTR6 cell line. Taken together, these results suggest that the targeting of CA IV to apical plasma membranes is impaired in CFPAC-1 cells. CA IV/gamma-adaptin double labeling demonstrated the presence of CA IV in the trans-Golgi network (TGN) of numerous CFPAC-1 cells, indicating that trafficking was disrupted on the exit face of the TGN. The retargeting of CA IV observed in CFPAC-PLJ-CFTR6 cells points to a relationship between the traffic of CFTR and CA IV. On the basis of these observations, we propose that the absence of CA IV in apical plasma membranes due to the impairment in targeting in cells expressing a deltaAF508 CFTR largely contributes to the disruption in HCO3- secretion in CF epithelia.
    European Journal of Cell Biology 09/2002; 81(8):437-47. DOI:10.1078/0171-9335-00264 · 3.83 Impact Factor
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    ABSTRACT: Patients with cystic fibrosis homozygous for the AF508 mutation have marked disturbances in ion exchanges in a variety of tissues. Alterations in intra- or extracellular levels of Ca2+ and calcifications have been observed in numerous tissues from such patients, although the nature and origin of such calcifications have yet to be elucidated. In this study, we investigated the formation of calcifications in the respiratory tract of a AF508 homozygous child and attempted to establish their origin. Samples of bronchial epithelium from this patient were subjected to cytophysiological analysis ex vivo and in vitro. The defect of targeting of the cystic fibrosis transmembrane conductance regulator (CFTR) to the apical plasma membrane of epithelial cells was verified. Cytochemical and ultrastructural analysis revealed the presence of crystalline aggregates in fine needles in the respiratory tract. Cytochemical analysis, X-ray spectrometry, and electron diffraction showed that these aggregates corresponded to crystals of calcium phosphate in an apatite-like structure. Ultrastructural study of primary cultures of bronchial epithelium showed the presence of calcium phosphate crystals in granules from Golgi apparatus and in mitochondria. These observations indicated that modifications of ionic exchanges due to a defect in targeting of CFTR AF508 to the apical plasma membrane led to the formation of crystals of calcium phosphate in the cytoplasm of pulmonary cells. These crystals could enhance inflammation of the lung in patients with cystic fibrosis.
    Archiv für Pathologische Anatomie und Physiologie und für Klinische Medicin 12/2001; 439(5):683-90. DOI:10.1007/s004280100425 · 2.65 Impact Factor
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    L Alvarez · M Fanjul · N Carter · E Hollande
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    ABSTRACT: The subcellular distribution of carbonic anhydrase II, either throughout the cytosol or in the cytoplasm close to the apical plasma membrane or vesicular compartments, suggests that this enzyme may have different roles in the regulation of pH in intra- or extracellular compartments. To throw more light on the role of pancreatic carbonic anhydrase II, we examined its expression and subcellular distribution in Capan-1 cells. Immunocytochemical analysis by light, confocal, and electron microscopy, as well as immunoblotting of cell homogenates or purified plasma membranes, was performed. A carbonic anhydrase II of 29 kD associated by weak bonds to the inner leaflet of apical plasma membranes of polarized cells was detected. This enzyme was co-localized with markers of Golgi compartments. Moreover, the defect of its targeting to apical plasma membranes in cells treated with brefeldin A was indicative of its transport by the Golgi apparatus. We show here that a carbonic anhydrase II is associated with the inner leaflet of apical plasma membranes and with the cytosolic side of the endomembranes of human cancerous pancreatic duct cells (Capan-1). These observations point to a role for this enzyme in the regulation of intra- and extracellular pH.
    Journal of Histochemistry and Cytochemistry 09/2001; 49(8):1045-53. DOI:10.1177/002215540104900812 · 1.96 Impact Factor
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    ABSTRACT: In steroid target tissues, the presence of the corresponding hormone receptors is indicative of hormone dependence. In an attempt to assess the possible role of steroid hormones in the mechanism of growth and/or differentiation of cancerous pancreatic duct cells, the expression of estrogen receptor (ERalpha) was evaluated in human cancerous pancreatic duct cells (Capan-1) maintained in culture. These cells were selected as they acquire progressively a high degree of differentiation during growth in culture. In the present study, we showed that Capan-1 cells during growth in steroid-free medium associate spontaneously, become polarized, and form duct-like structures, features that are indicative of a high degree of differentiation. Capan-1 cells were also found to express ERalpha and progesterone receptor (PR). Immunoenzymatic assay showed maximal expression of ERalpha (236 +/ 55 fmol/mg protein) on the first day of the exponential growth phase, followed by a marked fall in expression (76.3%). At the onset of the stationary phase (Day 5), ERalpha levels were below 10 fmol/mg protein, becoming undetectable by Day 7. A similar time course was observed for PR: 18 +/- 0.9 fmol/mg protein at the onset of the exponential growth phase and no expression during the stationary phase. Addition of estradiol to 1-d-old cultures resulted in a twofold increase in PR expression, suggesting an induction of PR expression by estrogen. Immunocytochemical analysis with anti-ERalpha-1D5 antibodies showed nuclear and cytoplasmic localization of ERalpha in Capan-1 cells in the first 24 h of culture followed by a progressive disappearance thereafter. We also showed that cellular multiplication was increased by estradiol and progesterone during the exponential growth phase, pointing to the involvement of steroid hormones in the proliferation of nonpolarized Capan-1 cells. These results indicate that the expression of ERalpha is linked to the state of differentiation of the cells and make Capan-1 cells a model of choice to study ER regulation in nontarget tissues.
    In Vitro Cellular & Developmental Biology - Animal 08/1998; 34(7):593-9. DOI:10.1007/s11626-998-0120-z · 1.15 Impact Factor
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    ABSTRACT: A relationship between targeting of the protein CFTR (Cystic Fibrosis Transmembrane conductance Regulator) and cellular polarization has been observed in various types of epithelial cells. However, there are no reports on this in human exocrine pancreatic cells, which are functionally altered in patients with cystic fibrosis. The expression of CFTR and its targeting to apical plasma membranes was investigated during growth and polarization of human ductal pancreatic cancerous Capan-1 cells. Despite their neoplastic origin, the cancerous pancreatic duct cells of the Capan-1 line secrete Cl- and HCO3- ions. We showed by electron microscopy, impregnation of cells with tannin and freeze-fracture that these cells become polarized during growth in culture, and are joined by tight junctions. The expression of CFTR and the various stages in its anchorage to membranes was followed using a specific polyclonal antibody, ECL-885, directed against a synthetic peptide mimicking one of the extracellular loops of CFTR. Qualitative and quantitative confocal microscopic studies showed that: (i) the expression of CFTR was constant during growth, irrespective of cellular conformation, (ii) the number of cells presenting CFTR anchored to membranes increased with time in culture, (iii) the rise in membrane-bound CFTR-immunoreactivity accompanied the polarization of the cells, (iv) CFTR anchored to plasma membranes was distributed regularly over the surface of non-polarized cells, but was localized only at the apical membranes of the polarized cells. Moreover, patch-clamp studies indicated the presence of few Cl- cAMP-dependent conductance CFTR channels on unpolarized cells, and a larger number of CFTR channels on the apical plasma membranes of polarized cells. These results indicated that the anchorage of a functional CFTR to the plasma membrane is progressive and occurs in step with polarization of these human pancreatic duct cells in culture. We suggest that the targeting of CFTR to the apical membranes is directly linked to the process of cellular polarization.
    European Journal of Cell Biology 08/1998; 76(3):220-7. DOI:10.1016/S0171-9335(98)80037-X · 3.83 Impact Factor

Publication Stats

504 Citations
146.14 Total Impact Points


  • 2009–2015
    • University of Toulouse
      Tolosa de Llenguadoc, Midi-Pyrénées, France
  • 2010
    • French Institute of Health and Medical Research
      Lutetia Parisorum, Île-de-France, France
  • 1991–2007
    • Paul Sabatier University - Toulouse III
      • Centre de Biologie du Développement - UMR 5547 - CBD
      Tolosa de Llenguadoc, Midi-Pyrénées, France
  • 2003
    • Institut de Génétique et de Biologie Moléculaire et Cellulaire
      Strasburg, Alsace, France
  • 1998
    • University of Bonn
      • Institute of Genetics
      Bonn, North Rhine-Westphalia, Germany