A novel tumor-associated pancreatic glycoprotein is internalized by human dendritic cells and induces their maturation.

Aberrant glycosylation or overexpression of cell-surface glycosylated tumor-associated Ags (TAA) distinguish neoplastic from normal cells. Interactions of TAA MUC1 and HER2/neu with dendritic cells (DC) preclude efficient processing, which impairs immune responses. It is thus important to define the mechanisms of interactions between DC and glycosylated TAA and their trafficking and processing for further T cell activation. In this work, we study interactions between DC and the oncofetal fucose-rich glycovariants of bile salt-dependent lipase (BSDL), expressed in pancreatic cancer tissues and referred to as pathological BSDL carrying the fucosylated J28 glycotope (pBSDL-J28) because it is characterized by the mAb J28. The expression of pBSDL-J28 was assessed by immunohistochemistry and quantified by confocal microscopy. Nontumoral pancreatic tissues and cells do not express pBSDL-J28. Using multidisciplinary approaches and functional studies, we provide the first evidence, to our knowledge, that this tumoral glycoprotein is rapidly internalized by human DC through macropinocytosis and endocytosis via mannose receptors and then transported to late endosomes for processing. Interestingly, pBSDL-J28 per se induced DC maturation with increased expression of costimulatory and CD83 molecules associated with cytokine secretion (IL-8 and IL-6). Surprisingly, DC retained their full ability to internalize Ags, making this maturation atypical. Finally, the allogeneic pBSDL-J28-treated DC stimulated lymphocyte proliferation. Besides, pulsing DC with pBSDL-J28 C-terminal glycopolypeptide and maturation with CD40L triggered CD4(+) and CD8(+) T cell proliferation. Therefore, interactions of pBSDL-J28, expressed on tumoral pancreatic tissue, with DC may lead to adequate Ag trafficking and processing and result in T cell activation.

Monoclonal antibody 16D10 to the COOH-terminal domain of the feto-acinar pancreatic protein targets pancreatic neoplastic tissues.

We have shown that the 16D10 antigen located on the mucin-like COOH-terminal domain of the feto-acinar pancreatic protein (FAPP) is expressed at the surface of human pancreatic tumor cell lines such as SOJ-6 cell line. Furthermore, an in vivo study indicates that targeting this cell-membrane glycopeptide by the use of the monoclonal antibody (mAb) 16D10 inhibits the growth of SOJ-6 xenografts in nude mice. To validate the potential use of the mAb16D10 in immune therapy, this study examined the expression of 16D10 antigens at the surface of human pancreatic adenocarcinomas versus control tissues. We examined the reactivity of mAb16D10 and mAb8H8 with pancreatic ductal adenocarcinomas (PDAC) compared with controls by using immunohistochemistry and confocal laser scanning microscopy. mAb8H8 does react with control or nontumoral human pancreatic tissues. mAb16D10 has a strong and specific reactivity with PDAC and does not react with other cancers of epithelia or normal tissues tested. Notable, mAb16D10 mostly recognizes membrane of tumoral cells. Furthermore, mAb8H8 and mAb16D10 recognized a protein of 110 to 120 kDa in homogenates of nontumoral and tumoral human pancreatic tissues, respectively. This size correlates with that of FAPP or with that of the normal counterpart of FAPP, the so-called bile salt-dependent lipase. The results suggest that mAb16D10 presents a unique specificity against PDAC; consequently, it could be effective in immune therapy of this cancer. Furthermore, mAb16D10 and mAb8H8 pair might be useful for diagnosis purpose in discriminating tumoral from nontumoral human pancreatic tissues.

Prevention by dietary (n-6) polyunsaturated phosphatidylcholines of intrahepatic cholestasis induced by cyclosporine A in animals.

Previous findings showed that dietary (n-6) polyunsaturated phosphatidylcholines (vegetable lecithin) could efficiently prevent intrahepatic cholestasis induced by cyclosporine A in rats. Mechanistic studies showed that expressions in rat liver of Na(+), K(+)-ATPase, Ca(2+), Mg(2+)-ATPase and F-actin were both decreased by drug administration and both enhanced by (n-6) lecithin enriched diet. There is a possible direct effect of phosphatidylcholines, vectors of polyunsaturated fatty acids provided by the metabolism of the dietary lecithin, on the aforesaid hepatic parameters. Such modulations by drug and diet result in reversed modifications of membrane composition and fluidity. Final outcome is decreased and enhanced bile lipid secretion by cyclosporine and vegetable lecithin enriched diet respectively. Moreover, we advance the hypothesis of a bypass process including a separate and functional actin-independent way for the non micellar and phospholipid-dependent secretion of bile lipids. The relationships between the ATPases, the microfilament components such as F-actin and the different transporters still remain to be clarified. Furthermore, one can speculate on beneficial effects in humans of diets enriched in vegetable lecithins that might prevent cholestasis induced by cyclosporine A.

Further characterization of HDAC and SIRT gene expression patterns in pancreatic cancer and their relation to disease outcome.

Ductal adenocarcinoma of the pancreas is ranking 4 for patient' death from malignant disease in Western countries, with no satisfactory treatment. We re-examined more precisely the histone deacetylases (HDAC) and Sirtuin (SIRT) gene expression patterns in pancreatic cancer with more pancreatic tumors and normal tissues. We also examined the possible relationship between HDAC gene expression levels and long term disease outcome. Moreover, we have evaluated by using an in vitro model system of human pancreatic tumor cell line whether HDAC7 knockdown may affect the cell behavior. We analyzed 29 pancreatic adenocarcinoma (PA), 9 chronic pancreatitis (CP), 8 benign pancreatic (BP) and 11 normal pancreatic tissues. Concerning pancreatic adenocarcinoma, we were able to collect biopsies at the tumor periphery. To assess the possible involvement of HDAC7 in cell proliferation capacity, we have generated recombinant human Panc-1 tumor which underexpressed or overexpressed HDAC7. The expression of HDAC1,2,3,4,7 and Nur77 increased in PA samples at levels significantly higher than those observed in the CP group (p = 0.0160; 0.0114; 0.0227; 0.0440; 0.0136; 0.0004, respectively). The expression of HDAC7, was significantly greater in the PA compared with BP tissue samples (p = 0.05). Mean mRNA transcription levels of PA for HDAC7 and HDAC2 were higher when compared to their counterpart biopsies taken at the tumor periphery (p = 0.0346, 0.0053, respectively). Moreover, the data obtained using confocal microscopy and a quantitative method of immunofluorescence staining strongly support the HDAC7 overexpression in PA surgical specimens. The number of deaths and recurrences at the end of follow up were significantly greater in patients with overexpression of HDAC7. Interestingly, the rate of growth was significantly reduced in the case of cell carrying shRNA construct targeting HDAC7 encoding gene when compared to the parental Panc-1 tumor cells (p = 0.0015) at 48 h and 96 h (p = 0.0021). This study strongly support the notion that HDAC7play a role in pancreatic adenocarcinoma progression.

Relationship between alphaGal epitope expression and decrease of tumorigenicity in pancreatic adenocarcinoma model.

The alphaGal epitope is a carbohydrate structure, Galalpha1,3Galbeta1,4GlcNAc-R, synthesized on glycoconjugates in many mammals by alpha1,3galactosyltransferase. Humans do not express this epitope and present in serum large amounts of naturally occuring antibodies, which recognize the alphaGal epitopes and participate in the hyperacute rejection of xenograft. Studies indicated that the fundamental mechanism of hyperacute rejection involving the alphaGal epitope expression can be used in cancer therapy. We have previously suggested that the alphaGal epitope expression by human pancreatic tumoral cells could decrease the tumorigenic behavior of these cells. To determine whether the expression of the alphaGal epitope can modify the tumorigenicity of pancreatic cancer cells, we used a Syrian golden hamster pancreatic adenocarcinoma experimental model. The expression of alphaGal epitopes in the Syrian golden hamster pancreatic cancer cell line HaP-T1 was obtained by selecting stable cell clones transfected with murine alpha1,3galactosyltransferase gene. The alphaGal epitope expression resulted in a delay in the tumoral development of HaP-T1 cells in vivo after allograft transplantation of Syrian golden hamsters (2.5-fold, P < 0.05) and of nude mice. This result is associated with an 100% increase in survival time of nude mice bearing tumors expressing the alphaGal epitope. Our results confirm that the cell surface expression of alphaGal epitope decreases the tumorigenic behavior of pancreatic cancer cells. This novel property may be useful for the development of cancer gene immunotherapy strategy.

Effect of ischemia-reperfusion on Na+, K+-ATPase expression in human liver tissue allograft: image analysis by confocal laser scanning microscopy.

We have analyzed the effect of ischemia-reperfusion on expression of hepatic Na+,K+-ATPase on bile canalicular (BCM) and basolateral membranes (BLM) in human liver allografts using confocal laser scanning microscopy imaging. Na+, K+-ATPase, an integral membrane enzyme, plays a key role in the physiology and structure of hepatocytes, where it maintains the electrochemical gradients for Na+ and K+ across the cell membrane. The concentrations of these ions as well as their gradients regulate the active transport across the plasma membrane for bile acid and water from sinusoidal to canalicular membranes. In addition, Na+,K+-ATPase is also involved in cellular structure because of its close relationship with submembrane microfilaments and its implication in tight junction assembly. Therefore, Na+,K+-ATPase appears as an indicator of tissue viability and hepatic functionality during liver transplantation. Its localization and its function in BCM are still controversial. As in previous studies, we found an enzyme expression in both BLM and BCM. We show that ischemia induced a decrease in Na+,K+-ATPase expression only in BCM. This result could be explained by the differences in biochemical membrane environment between basolateral and bile canalicular Na+,K+-ATPase. Membrane lipid fluidity, which is more elevated in BLM than in BCM, could protect the enzyme during ischemia. After reperfusion, Na+,K+-ATPase expression was strongly decreased in both BCM and BLM. This alteration following reperfusion is probably due to multiple factors: direct alteration of the enzyme catalytic subunit and modification of its environment and membrane lipid fluidity by free radicals and changes in ATP levels and ionic distribution. This important decrease in Na+,K+-ATPase expression of both BLM and BCM could disturb not only hepatic secretory function but also cellular volume and structure during the postoperative period.

Expression of intercellular adhesion molecule-1 (ICAM- 1) during ischemia-reperfusion in human liver tissue allograft: image analysis by confocal laser scanning microscopy.

We studied and quantified the effect of ischemia-reperfusion on expression of intercellular adhesion molecule-1 (ICAM-1) on sinusoidal endothelial cells and hepatocyte plasma membranes by means of confocal laser scanning microscopy imaging. We found that ischemia induced an increase in ICAM-1 expression on sinusoidal endothelial cells and hepatocytes. After reperfusion, ICAM-1 expression was increased on sinusoidal endothelial cells, whereas it was unmodified on hepatocytes. On the other hand, ICAM-1 expression was not correlated to ischemia-reperfusion liver injury. Therefore, hepatocellular ischemia-reperfusion injury could be induced by other causes than immune-mediated damages.