J Histochem Cytochem
September 2010
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.
View Article and Find Full Text PDFThe 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.
View Article and Find Full Text PDFPlatelets are critical for normal hemostasis. Their deregulation can lead to bleeding or to arterial thrombosis, a primary cause of heart attack and ischemic stroke. Src homology 2 domain-containing inositol 5-phosphatase 1 (SHIP1) is a 5-phosphatase capable of dephosphorylating the phosphatidylinositol 3,4,5-trisphosphate second messenger into phosphatidylinositol 3,4-bisphosphate.
View Article and Find Full Text PDFThe 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.
View Article and Find Full Text PDFRecent studies have shown the involvement of the Fas system (Fas receptor and its ligand FasL) in cancerous processes. The absence or downregulation of Fas, reported in the majority of human tumors, conflicts with its presence in cancerous cells from the same tumors but maintained in vitro. Recently, the eventual role of environmental factors in the loss of Fas expression, or in the in vivo selection of a Fas-negative cell population has been suggested.
View Article and Find Full Text PDFJ Mater Sci Mater Med
March 2001
The aim of the present study was to assess the effect of three calcium phosphate powders entering in the composition of bone substitute materials on osteoblast-cells activity. These powders were hydroxyapatite (HA) widely used as a biomaterial, nanocrystalline carbonate apatite (C A) very close to bone mineral crystals, and an experimental one: calcium phosphate cement-1 (CPC-1) composed of an amorphous Ca-P phase and brushite. The powders were physico-chemically characterized.
View Article and Find Full Text PDFJ Mater Sci Mater Med
April 2001
The aim of our study was to assess the ability of calcium phosphate powders to serve as growth factor carriers. Vascular endothelial growth factor (VEGF), in particular, is locally involved in the bone formation process throughout osteoblast differentiation. Two different apatitic substrates were tested: hydroxyapatite (HA), widely used as biomaterial, and nanocrystalline carbonated apatite (CA), which has a composition similar to bone mineral crystals.
View Article and Find Full Text PDFAlveolar 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.
View Article and Find Full Text PDFThe 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.
View Article and Find Full Text PDFThe 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.
View Article and Find Full Text PDFPlasma levels of glucose, insulin and glucagon were measured at various time intervals after pancreatic duct ligation (PDL) in rabbits. Two hyperglycemic periods were observed: one between 15-90 days (peak at 30 days of 15.1 +/- 1.
View Article and Find Full Text PDFHuman 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.
View Article and Find Full Text PDFPatients 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.
View Article and Find Full Text PDFJ Histochem Cytochem
August 2001
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.
View Article and Find Full Text PDFHaving developed a non-insulin-dependent diabetes mellitus (NIDDM) syndrome model in the rabbit using Wirsung duct ligation, it appeared interesting to use it to study the relationship between glycemia and the plasma levels of TXA(2)and PGI(2), and of some other biochemical parameters such as cholesterol, triglycerides, alkaline phosphatase and transaminases. A comparative study was carried out in the sham-operated rabbits (controls, C) and those having their pancreatic duct ligatured (NIDDM, D) at 15, 30, 40, 50 and 60 days post-ligation. On the 40th days, whereas in the controls, glycemia was 1.
View Article and Find Full Text PDFPancreatic tumors overexpress FGF-2 and t-PA, but the implication of the growth factor in t-PA synthesis and t-PA-dependent tumor invasion remains unknown. FGF-2 is present in different isoforms: The 18 kDa FGF-2 is secreted, while the 22.5 kDa one is nuclearized and exerts intracrine regulations bypassing cell-surface FGF receptors.
View Article and Find Full Text PDFKlin Monbl Augenheilkd
May 1999
Purpose: Active HCO3- transport through the corneal endothelial cell layer causes a dehydration of the corneal stroma and is thought to be driven by Na/K- and HCO3(-)-dependent ATPase as well as an electro-genic Na/HCO3- cotransport. Transmembrane bicarbonate transport has also been associated with the recently characterised membrane-anchored isoform of carbonic anhydrase (CA IV) in various tissues. We investigated the localisation of CA IV in human fresh and cultured epi- and endothelium at the light- (LM) and electron-microscopic (EM) level.
View Article and Find Full Text PDFIn Vitro Cell Dev Biol Anim
November 1998
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.
View Article and Find Full Text PDFA 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.
View Article and Find Full Text PDFGastric M1 mucin and the MUC5AC gene show a similar oncofetal expression in the colon. Our aim was to determine whether M1 mucin is the product of the MUC5AC gene. A recombinant baculovirus encoding the C-terminal portion of the MUC5AC gene as a fusion protein was isolated and the immunoreactivity of the recombinant mucin (rM) toward M1 antibodies studied.
View Article and Find Full Text PDFThe trypanocidal activity of naturally occurring 6-(3,4-dihydroxystyryl)-4-hydroxy-2-pyrone (hispidin) prompted us to examine its cytotoxic activity toward normal and cancerous cells in culture. Hispidin synthesized in our laboratory to a high degree of purity (checked by 1H and 13C NMR spectroscopy) was shown to be cytotoxic (between 10(-3) mol/L and 10(-7) mol/L) toward normal human MRC-5 fibroblasts, human cancerous keratinocytes (SCL-1 cell line), and human cancerous pancreatic duct cells (Capan-1 cell line). Interestingly, addition of hispidin in three successive doses (between 10(-5) mol/L and 10(-7) mol/L) led to a 100-fold increase in activity with an enhanced activity on cancer cells compared to normal cells (50%).
View Article and Find Full Text PDFLow-density lipoproteins (LDL) labeled with indium via a lipid-chelating agent, the bis(stearylamide) of diethylenetri-aminepentaacetic acid (L), were evaluated as a potential radiopharmaceutical (111In-L-LDL) for tumor localization by studying their internalization in human pancreatic cancer cells (Capan-1). Using Dil-LDL (1,1'-dioctadecyl-3,3,3',3'-tetramethylindodicarbocyanine perchlorate-LDL), this cell line was shown to bind human LDL with a high-affinity saturable component and a low-affinity non-saturable (40%) component. The single saturable high-affinity binding site had a KD of 27.
View Article and Find Full Text PDFThe injection of alpha-MSH or of one of its analogues ([Nle4-D.Phe7] alpha-MSH4-10) reduced, in vivo, the release of two cytokines (IL-1 alpha and TNF alpha) involved in inflammation. The inflammatory state was induced in BALB/c mice by intraperitoneal injection of a sublethal dose of lipopolysaccharides (LPS).
View Article and Find Full Text PDFBasic fibroblast growth factor (FGF-2) is synthesized as different molecular mass isoforms all lacking the signal-peptide sequence. The high molecular-mass isoforms (21-24 kDa) possess a signal sequence directing their nuclear translocation. The role of each isoform is still poorly understood, however, modifications in intracellular signalling pathways could explain some effects of these peptides.
View Article and Find Full Text PDFFibroblast growth factor (FGF-2) is a multifunctional growth factor. In cells producing this factor, FGF-2 is synthesized as different molecular weight isoforms lacking the signal peptide sequence for secretion. All forms are highly concentrated in cells.
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