654 Analysis of IDO-1 expression on dendritic cells and factors influencing its up- and downregulation in pancreatic cancer

Background

Pancreatic Ductal Adenocarcinoma (PDAC) is bad. An immunosuppressive tumor microenvironment (TME) with an excess of immunosuppressive immune cells and cytokine/chemokine factors contribute to local and systemic immunosuppression in PDAC.1 Our laboratory has generated single-cell RNA-Sequencing (scRNA-Seq.) data from spleens derived from PDAC patients and healthy counterparts. This data demonstrates the existence of dendritic cell (DC) subsets with a tolerogenic phenotype. These DCs display increased expression of several markers, including Indoleamine 2,3-dioxygenases (IDO-1 and IDO-2), widely accepted as markers for a specific population of DCs: tolerogenic DCs. These cells evoke an immunosuppressive signal leading to activation of regulatory T cells and MDSCs as well as apoptosis of CD8+ and CD4+ effector T cells.2 3

Methods

To validate our scRNA-Seq. data, we performed pilot investigations harvesting DCs from the spleen of PDAC patients and healthy subjects. Besides examining human specimens, we also investigated the IDO-1 expression on splenic DCs from tumor-bearing mice, orthotopically implanted with LSL-KrasG12D; LSL-Trp53R172H/+; Pdx1-Cre (KPC)-derived cell lines. It is known that tumor-derived exosomes can impact DC-differentiation to a tolerogenic phenotype.4 Exosome purification using differential ultracentrifugation is a well-established method in our lab and optimized for our autopsy samples. We analyzed tumor-derived exosomes for their potential in modulating IDO-1 expression on DCs in in vitro assays. Briefly, we incubated DCs with different exosome concentrations and harvested the cells for RNA-sequencing and flow cytometry.

Results

Compared to normal spleens, DCs from PDAC spleens displayed higher expression of IDO-1 (figure 1). Additionally, KPC-tumor-bearing mice showed higher expression of IDO-1 on DCs from the spleen and blood compared to wild-type mice. Further investigating the influence of PDAC-derived exosomes on marker expression on DCs have shown an apparent increase in expression of IDO-1 when culturing splenic-derived DCs with tumor-derived exosomes (figure 2).

Conclusions

While tolerogenic DCs are essential in regulating the homeostasis between immune response and immune tolerance,5 several studies have shown IDO-1 overexpression in cancer. Investigating tolerogenic DCs is an essential part of our lab's efforts to understand the nature of the immune response in PDAC. Future directions for this project include determining molecular pathways that regulate the expression of IDO-1. Additionally, we will investigate downstream mechanisms through which exosomes modulate the switch to a tolerogenic phenotype. We also plan to further characterize different splenic DC populations by evaluating their interplay with other immune cells in the context of antigen-specificity and other factors influencing these cells' properties.

References

Mundry CS, Eberle KC, Singh PK, Hollingsworth MA, Mehla K. Local and systemic immunosuppression in pancreatic cancer: targeting the stalwarts in tumor's arsenal. BBA - Reviews on Cancer 2020;1874(1):188387.

Liu M, Wang X, Wang L, Ma X, Gong Z, Zhang S, Li Y. Targeting the IDO1 pathway in cancer: from bench to bedside. Journal of Hematology & Oncology 2018;11(1):100.

Hornyák L, Dobos N, Koncz G, Karányi Z, Páll D, Szabó Z, Halmos G, Székvölgyi L. The role of Indoleamine-2,3-Dioxygenase in cancer development, diagnostics, and therapy. Frontiers in immunology 2018;9:1.

Bronte V, Pittet MJ. The spleen in local and systemic regulation of immunity. Immunity 2013;39(5):806–818.

Domogalla MP, Rostan PV, Raker VK, Steinbrink K. Tolerance through education: how tolerogenic dendritic cells shape immunity. Frontiers in Immunology 2017;8:1764.

Ethics Approval

This study was approved by the University of Nebraska Medical Center Ethics Board; approval numbers IRB#: 440-16-EP and IRB#: 091-01.

Abstract 654 Figure 1

Expression of IDO-1 and IDO-2 on DCs from PDAC spleen (blue) .and normal spleen (orange)

Abstract 654 Figure 2

Change in expression of IDO-1 through treatment of DCs with different concentrations of tumor-derived exosomes

Isoforms of MUC16 activate oncogenic signaling through EGF receptors to enhance the progression of pancreatic cancer

Aberrant expression of CA125/MUC16 is associated with pancreatic ductal adenocarcinoma (PDAC) progression and metastasis. However, knowledge of the contribution of MUC16 to pancreatic tumorigenesis is limited. Here, we show that MUC16 expression is associated with disease progression, basal-like and squamous tumor subtypes, increased tumor metastasis, and short-term survival of PDAC patients. MUC16 enhanced tumor malignancy through the activation of AKT and GSK3β oncogenic signaling pathways. Activation of these oncogenic signaling pathways resulted in part from increased interactions between MUC16 and epidermal growth factor (EGF)-type receptors, which were enhanced for aberrant glycoforms of MUC16. Treatment of PDAC cells with monoclonal antibody (mAb) AR9.6 significantly reduced MUC16-induced oncogenic signaling. mAb AR9.6 binds to a unique conformational epitope on MUC16, which is influenced by O-glycosylation. Additionally, treatment of PDAC tumor-bearing mice with either mAb AR9.6 alone or in combination with gemcitabine significantly reduced tumor growth and metastasis. We conclude that the aberrant expression of MUC16 enhances PDAC progression to an aggressive phenotype by modulating oncogenic signaling through ErbB receptors. Anti-MUC16 mAb AR9.6 blocks oncogenic activities and tumor growth and could be a novel immunotherapeutic agent against MUC16-mediated PDAC tumor malignancy.

The glycoprotein mucin-1 negatively regulates GalNAc transferase 5 expression in pancreatic cancer

Aberrant expression of the glycoprotein mucin-1 (MUC1) has been associated with pancreatic cancer progression and metastasis as a result of mediating the oncogenic transcriptional regulation of target genes. In the present study, we demonstrate that MUC1 downregulates the expression of the tumor suppressor polypeptide N-acetylgalactosaminyltransferase 5 in pancreatic cancer. ChIP-on-chip analysis revealed that the MUC1 cytoplasmic tail binds to regulatory elements in the GALNT5 gene. Additionally, MUC1 increases binding of p53 and c-Jun and decreases the binding of Sp1 to the proximal promoter and exonic regions of GALNT5. We also observed that expression of N-acetylgalactosaminyltransferase 5 is inversionally proportional to MUC1 expression in human pancreatic cancer. These results demonstrate that MUC1 downregulates the expression of N-acetylgalactosaminyltransferase 5 in pancreatic cancer by modifying the promoter occupancy of transcription factors through its cytoplasmic domain.

Truncated O-glycans promote epithelial-to-mesenchymal transition and stemness properties of pancreatic cancer cells

Aberrant expression of Sialyl-Tn (STn) antigen correlates with poor prognosis and reduced patient survival. We demonstrated that expression of Tn and STn in pancreatic ductal adenocarcinoma (PDAC) is due to hypermethylation of Core 1 synthase specific molecular chaperone (COSMC) and enhanced the malignant properties of PDAC cells with an unknown mechanism. To explore the mechanism, we have genetically deleted COSMC in PDAC cells to express truncated O-glycans (SimpleCells, SC) which enhanced cell migration and invasion. Since epithelial-to-mesenchymal transition (EMT) play a vital role in metastasis, we have analysed the induction of EMT in SC cells. Expressions of the mesenchymal markers were significantly high in SC cells as compared to WT cells. Equally, we found reduced expressions of the epithelial markers in SC cells. Re-expression of COSMC in SC cells reversed the induction of EMT. In addition to this, we also observed an increased cancer stem cell population in SC cells. Furthermore, orthotopic implantation of T3M4 SC cells into athymic nude mice resulted in significantly larger tumours and reduced animal survival. Altogether, these results suggest that aberrant expression of truncated O-glycans in PDAC cells enhances the tumour aggressiveness through the induction of EMT and stemness properties.

A Polymeric Nanogel-Based Treatment Regimen for Enhanced Efficacy and Sequential Administration of Synergistic Drug Combination in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers. A combination of cisplatin (CDDP) and gemcitabine (Gem) treatment has shown favorable clinical results for metastatic disease; both are limited by toxicities and nontargeted delivery. More than 80% of PDAC aberrantly expresses the sialyl Tn (STn) antigen due to the loss of function of the core 1β3-Gal-T-specific molecular chaperone, a specific chaperone for the activity of core 1 β3-galactosyltransferase or C1GalT. Here, we report the development of polymeric nanogels (NGs) loaded with CDDP and coated with an anti-STn antigen-specific antibody (TKH2 monoclonal antibody) for the targeted treatment of PDAC. TKH2-functionalized, CDDP-loaded NGs delivered a significantly higher amount of platinum into the cells and tumors expressing STn antigens. We also confirmed that a synergistic cytotoxic effect of sequential exposure of pancreatic cancer cells to Gem followed by CDDP can be mimicked by the codelivery of CDDP-loaded NGs (NG/CDDP) and free Gem. In a murine orthotopic model of PDAC, combined simultaneous treatment with Gem and targeted NG/CDDP significantly attenuated tumor growth with no detectable acute toxicity. Altogether, these results suggest that combination therapy consisting of Gem followed by TKH2-conjugated CDDP NGs induces highly synergistic therapeutic efficacy against pancreatic cancer. Our results offer the basis for development of combination drug regimens using targeted nanomedicines to increase treatment effectiveness and improve outcomes of PDAC therapy.

SOX2 functions as a molecular rheostat to control the growth, tumorigenicity and drug responses of pancreatic ductal adenocarcinoma cells

Pancreatic ductal adenocarcinoma (PDAC) is a highly deadly malignancy. Expression of the stem cell transcription factor SOX2 increases during progression of PDAC. Knockdown of SOX2 in PDAC cell lines decreases growth in vitro; whereas, stable overexpression of SOX2 in one PDAC cell line reportedly increases growth in vitro. Here, we reexamined the role of SOX2 in PDAC cells, because inducible SOX2 overexpression in other tumor cell types inhibits growth. In this study, four PDAC cell lines were engineered for inducible overexpression of SOX2 or inducible knockdown of SOX2. Remarkably, inducible overexpression of SOX2 in PDAC cells inhibits growth in vitro and reduces tumorigenicity. Additionally, inducible knockdown of SOX2 in PDAC cells reduces growth in vitro and in vivo. Thus, growth and tumorigenicity of PDAC cells is highly dependent on the expression of optimal levels of SOX2 – a hallmark of molecular rheostats. We also determined that SOX2 alters the responses of PDAC cells to drugs used in PDAC clinical trials. Increasing SOX2 reduces growth inhibition mediated by MEK and AKT inhibitors; whereas knockdown of SOX2 further reduces growth when PDAC cells are treated with these inhibitors. Thus, targeting SOX2, or its mode of action, could improve the treatment of PDAC.

Abstract A30: AR20.5-based novel immunotherapy for pancreatic cancer

Pancreatic cancer is a fourth leading cause of cancer death in United States. Recent advances in tumor immunology have provided evidence for immune surveillance against pancreatic cancer. Previous studies have documented the presence of specific antibodies and cytotoxic T cell activities to Mucin 1 (MUC1), an antigen that is expressed in most pancreatic cancers. Hence, MUC1 remains a candidate for immunotherapeutic strategies for pancreatic cancer. Numerous attempts have been made to target this mucin glycoprotein; however, these efforts have shown only moderate success in part due to the complexity of the pancreatic tumor microenvironment. Previously, administration of murine monoclonal antibody BrevaRexAb-AR20.5 alone produced MUC1 specific immune response in a phase I study of advanced cancer patients, including increased human anti-MUC1 antibody levels and MUC1 specific T cell response in few patients. Though this was a phase I study, modest changes in tumor marker (CA15.3) but no anecdotal anti-tumor activity was observed in this small group of patients. Moving forward it is obvious that future immunization strategies should include other immune-modulators to amplify MUC1 specific immune responses of mAbAR20.5 and enhance other factors that contribute to tumor rejection. To that end, we investigated the anti-tumor effect of mAbAR20.5 in combination with anti-PD-L1 and poly (I:C) in murine models of pancreatic adenocarcinoma using human MUC1 expressing transgenic (hMUC1.Tg) mice, which are immunologically tolerant to MUC1. The therapeutic combination of mAb-AR20.5+anti-PD-L1+Poly (I:C) induced rejection or significant inhibition of tumor growth for two different MUC1 expressing pancreatic tumor cell lines, which was accompanied by persistent MUC1 specific memory immune response, which could be adoptively transferred to other mice and shown to protect against subsequent tumor challenge. We show that the anti-tumor response was effected by CD8 T cells, as their abrogation attenuated the anti-tumor response. Flow cytometric analysis of immunized mice demonstrated progressive increases in activated CD8 T cells in the peripheral circulation of combination treated mice. Together, these data support the hypothesis that targeting checkpoint induced immunosuppression (anti-PD-L1) together with the use of toll-like receptor 3 agonist as an adjuvant (poly (I:C) ) enhances the capacity of mAbAR20.5 to induce specific cell mediated immune responses to MUC1, which in turn provide long lasting anti-tumor response against pancreatic tumors. Our study supports the rapid translation of this strategy into clinical trials for pancreatic cancer patients.

Citation Format: Kamiya Mehla, James A. Grunkemeyer, Kelly A. O'Connell, Maria M. Steele, Thomas Caffrey, Ragupathy Madiyalakan, Christopher F. Nicodemus, Michael A. Hollingsworth. AR20.5-based novel immunotherapy for pancreatic cancer. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2016 Oct 20-23; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2017;5(3 Suppl):Abstract nr A30.

Effect of MUC1/β-catenin interaction on the tumorigenic capacity of pancreatic CD133+ cells

Despite the fact that the biological function of cluster of differentiation (CD)133 remains unclear, this glycoprotein is currently used in the identification and isolation of tumor-initiating cells from certain malignant tumors, including pancreatic cancer. In the present study, the involvement of mucin 1 (MUC1) in the signaling pathways of a highly tumorigenic CD133+ cellular subpopulation sorted from the pancreatic cancer cell line HPAF-II was evaluated. The expression of MUC1-cytoplasmic domain (MUC1-CD) and oncogenic signaling transducers (epidermal growth factor receptor, protein kinase C delta, glycogen synthase kinase 3 beta and growth factor receptor-bound protein 2), as well as the association between MUC1 and β-catenin, were characterized in HPAF-II CD133+ and CD133low cell subpopulations and in tumor xenografts generated from these cells. Compared with HPAF CD133^low cells, HPAF-II CD133+ cancer cells exhibited increased tumorigenic potential in immunocompromised mice, which was associated with overexpression of MUC1 and with the accordingly altered expression profile of MUC1-associated signaling partners. Additionally, MUC1-CD/β-catenin interactions were increased both in the HPAF-II CD133+ cell subpopulation and derived tumor xenografts compared with HPAF CD133^low cells. These results suggest that, in comparison with HPAF CD133^low cells, CD133+ cells exhibit higher expression of MUC1, which contributes to their tumorigenic phenotype through increased interaction between MUC1-CD and β-catenin, which in turn modulates oncogenic signaling cascades.

Impact of MUC1 mucin downregulation in the phenotypic characteristics of MKN45 gastric carcinoma cell line

Background

Gastric carcinoma is the second leading cause of cancer-associated death worldwide. The high mortality associated with this disease is in part due to limited knowledge about gastric carcinogenesis and a lack of available therapeutic and prevention strategies. MUC1 is a high molecular weight transmembrane mucin protein expressed at the apical surface of most glandular epithelial cells and a major component of the mucus layer above gastric mucosa. Overexpression of MUC1 is found in approximately 95% of human adenocarcinomas, where it is associated with oncogenic activity. The role of MUC1 in gastric cancer progression remains to be clarified.

Methodology

We downregulated MUC1 expression in a gastric carcinoma cell line by RNA interference and studied the effects on cellular proliferation (MTT assay), apoptosis (TUNEL assay), migration (migration assay), invasion (invasion assay) and aggregation (aggregation assay). Global gene expression was evaluated by microarray analysis to identify alterations that are regulated by MUC1 expression. In vivo assays were also performed in mice, in order to study the tumorigenicity of cells with and without MUC1 downregulation in MKN45 gastric carcinoma cell line.

Results

Downregulation of MUC1 expression increased proliferation and apoptosis as compared to controls, whereas cell-cell aggregation was decreased. No significant differences were found in terms of migration and invasion between the downregulated clones and the controls. Expression of TCN1, KLK6, ADAM29, LGAL4, TSPAN8 and SHPS-1 was found to be significantly different between MUC1 downregulated clones and the control cells. In vivo assays have shown that mice injected with MUC1 downregulated cells develop smaller tumours when compared to mice injected with the control cells.

Conclusions

These results indicate that MUC1 downregulation alters the phenotype and tumorigenicity of MKN45 gastric carcinoma cells and also the expression of several molecules that can be involved in tumorigenic events. Therefore, MUC1 should be further studied to better clarify its potential as a novel therapeutic target for gastric cancer.

Abstract 2720: Glycosylation of Mucins Expressed in Pancreatic Adenocarcinoma

Glycosylation of mucins expressed by pancreatic adenocarcinoma

There were an estimated 42,470 new cases and 35,240 deaths due to pancreatic adenocarcinoma (PA) for 2009, ranking PA as the third leading cause of cancer related death. Virtually all long term survivors are diagnosed early but only 7% are detected in the early stages of disease thus highlighting the need for an early diagnostic test. CA19-9, the only current clinical serum-based assay used to monitor PA, detects an oligosaccharide blood group antigen Sialyl Lewisa (sLeA) with the structure (Neu5Acα2-3Galβ1-3[Fucα1-4]GlcNAc), which can be present on glycolipids or as an O-linked oligosaccharide on glycoproteins, and is expressed at relatively low levels on the surfaces of normal epithelial cells. The full spectrum of proteins on which the CA19-9 epitope is expressed has never been defined. CA19-9 is differentially expressed on mucins, which are extensively glycosylated. The CA19-9 test lacks high specificity for PA, as CA19-9 is commonly elevated in patients with benign chronic pancreatitis and other malignant diseases. Different epithelial tissues and cell types produce distinct combinations of mucin-type core proteins, and the expression patterns of these are generally altered during different disease processes including malignant transformation. Mucin expression is deregulated in cancer, which results in aberrant expression and glycosylation of mucin core proteins. We employed immunohistochemistry and immunofluorescence to show the unique mucin and glycosylation patterns seen in tissue specimens from patients diagnosed with PA. Deglycosylation of samples immunoprecipitated from cancer cell lines and pancreatic cancer patient tissue specimens was used to enable detection of mucin core proteins. Immunoaffinity chromatography was used to isolate CA19-9 from patient ascites and serum samples and mass spectrometry was used to analyze the core proteins. Results show that pancreatic cancers expressing the mucin core proteins MUC1, MUC4 and MUC5AC carry the CA19-9 epitope. Preliminary results suggest that a strategy to detect the CA19-9 tumor antigen and its cognate mucin core protein(s) will improve the performance characteristics of this assay.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2720.

Relevance of MUC1 mucin variable number of tandem repeats polymorphism in H pylori adhesion to gastric epithelial cells

AIM: To evaluate the influence of MUC1 mucin variable number of tandem repeats (VNTR) variability on H pylori adhesion to gastric cells.

METHODS: Enzyme linked immunosorbent assay (ELISA)-based adhesion assays were performed to measure the adhesion of different H pylori strains (HP26695 and HPTx30a) to gastric carcinoma cell lines (GP202 and MKN45) and GP202 clones expressing recombinant MUC1 with different VNTR lengths.

RESULTS: Evaluation of adhesion results shows that H pylori pathogenic strain HP26695 has a significantly higher (P < 0.05) adhesion to all the cell lines and clones tested, when compared to the non-pathogenic strain HPTx30a. Bacteria showed a significantly higher (P < 0.05) adhesion to the GP202 cell line, when compared to the MKN45 cell line. Furthermore, both strains showed a significantly higher (P < 0.05) adhesion to GP202 clones with larger MUC1 VNTR domains.

CONCLUSION: This work shows that MUC1 mucin variability conditions H pylori binding to gastric cells. The extent of bacterial adhesion depends on the size of the MUC1 VNTR domain. The adhesion is further dependent on bacterial pathogenicity and the gastric cell line. MUC1 mucin variability may contribute to determine H pylori colonization of the gastric mucosa.

T cells recognize PD(N/T)R motif common in a variable number of tandem repeat and degenerate repeat sequences of MUC1

The tumor-associated antigen MUC1 is a transmembrane glycoprotein, which is overexpressed in human carcinomas. Peptide epitopes, containing the PDTR fragment from the variable number of tandem repeat (VNTR) domains of MUC1 have been found to be immunodominant in T-cell and B-cell responses. However, little is known about the immunogenicity and specificity of T-cell epitopes from other regions of MUC1 that may also participate in immune responses against tumors. In this study, the combination of immunoinformatics, molecular modeling and a vaccine adjuvant strategy were used to predict and describe a novel T-cell epitope, SAPDNRPAL, located within the degenerate tandem repeat of MUC1. This peptide possesses structural similarity to both VNTR-derived SAPDTRPAP and Sendai virus peptide FAPGNYPAL, which are known to induce cytotoxic T lymphocytes (CTL). We found that SAPDNRPAL had a higher affinity for mouse H-D(b), H-2K(b) and human HLA-A2 molecules than SAPDTRPAP. A chimeric peptide (CP) containing SAPDNRPAL and an adjuvant C5a-derived decapeptide induced epitope-specific type 1 T cells in human MUC1 transgenic mice (ELISPOT). Mice that received dendritic cells (DC) pulsed with the CP or a 25-mer peptide containing the SAPDNRPAL sequence showed increased frequencies of SAPDNRPAL- and SAPDTRPAP-specific interferon-gamma producing T cells. PDTR-specific antibody 214D4 reacted with both SAPDNRPAL and SAPDTRPAP (ELISA). Altogether, our data suggest that the degenerate MUC1 repeat sequence contains the immunogenic T-cell epitope SAPDNRPAL, which is cross-reactive with the VNTR-derived peptide SAPDTRPAP. We suggest that the use of immunogenic PDNR-containing epitope(s) in vaccine strategies could be beneficial for developing increased, PD(N/T)R motif-specific T-cell responses against tumors expressing MUC1.

Thomsen-Friedenreich antigen expression in gastric carcinomas is associated with MUC1 mucin VNTR polymorphism

Aberrant glycosylation of mucins is a common phenomenon associated with oncogenic transformation. We investigated the association between expression of the tumor-associated antigens T, Tn, and sialyl-Tn and polymorphism in the length of the MUC1 mucin tandem repeat in a series of gastric carcinomas. We further evaluated the relevance of MUC1 tandem repeat length on the expression of these tumor-associated carbohydrate antigens (TACAs) using a gastric carcinoma cell line model expressing recombinant MUC1 constructs carrying 0, 3, 9, and 42 repeats. Gastric carcinomas showed a high prevalence of Tn and sialyl-Tn antigens, whereas T antigen was less frequently expressed. The expression of T antigen was significantly higher in gastric carcinomas from patients homozygous for MUC1 large tandem repeat alleles. No significant associations were found for Tn and sialyl-Tn antigens. This novel association was reinforced by the gastric carcinoma cell line model experiments, where de novo expression of T antigen was detected in clones transfected with larger VNTR regions. Our results indicate that polymorphism in the MUC1 tandem repeat influences the expression of TACAs in gastric cancer cells and may therefore allow the identification of subgroups of patients that develop more aggressive tumors expressing T antigen.

Expression of three UDP-N-acetyl-alpha-D-galactosamine:polypeptide GalNAc N-acetylgalactosaminyltransferases in adenocarcinoma cell lines

The levels of mRNA expression of three UDP-N-acetyl-alpha-D-galactosamine:polypeptide GalNAc N-acetylgalactosaminyltransferases (GalNAc-transferases) were quantified for human adenocarcinoma cell lines from pancreas, colon, stomach, and breast. Two of the GalNAc-transferases, GalNAc-T1 and GalNAc-T2, were expressed constitutively and at low levels in most or all cell lines examined. A third GalNAc-transferase, GalNAc-T3, was differentially expressed. Well-differentiated adenocarcinoma cell lines expressed high levels and moderately differentiated cell lines expressed lower levels of GalNAc-T3. Cell lines classified as poorly differentiated failed to express GalNAc-T3 mRNA at levels that could be detected by Northern blot analysis. Differential expression of the GalNAc-T3 protein was confirmed in these cell lines by Western blotting. We propose that glycosylation in tumor cell lines may be regulated in part by differential expression of GalNAc-transferases, and we suggest that GalNAc-T3 gene expression may be a molecular indicator of differentiated adenocarcinoma.

Duct epithelial cells cultured from human pancreas processed for transplantation retain differentiated ductal characteristics

A procedure is described for the isolation and growth in vitro of epithelial cells from the duct network of human pancreas, referred to as DEC. A significant advantage of our procedure over previously published procedures is that it enables the isolation of DEC from small pieces of pancreas tissue (< 5 g) and, also, from the digest remaining after the isolation of islet cells from human pancreas, material that would normally be discarded. These were the only reliable sources for pancreas tissue available to us. This procedure shows that some of the techniques that have been successfully used for the isolation of rodent DEC are also valuable in the isolation of human DEC. In particular, the use of cholera toxin to prevent fibroblast growth and contamination obviates the need for the time-consuming procedure of physically removing fibroblasts or the use of expensive fibroblast-specific monoclonal antibodies. The use of sieving to separate the digest immediately achieves a partial purification, which, coupled with that of allowing duct cysts to form, adds to the purity of the final preparation. The ductal system of the intact pancreas tissue and the DEC derived from it expressed cytokeratins 7, 8/18, and 19 and markers for the presence of MUC1, CFTR, and carbonic anhydrase II, which are specific for ductal epithelial cells or for pancreatic ductal functions. This study showed that it is possible to obtain selectively viable DEC from small ducts in otherwise waste pieces of human pancreas. It showed that these cells retained all of the epithelial characteristics that were examined and, in combination with data from an earlier study, showed that the cultured DEC retain the metabolic functions of duct epithelial cells in vivo.

Induction of experimental autoimmune sialoadenitis by immunization of PL/J mice with carbonic anhydrase II

Experimental autoimmune sialoadenitis was induced in PL/J (H-2u) mice by intradermal immunization with human carbonic anhydrase II (CAII) and adjuvant containing monophosphoryl lipid A and trehalose diorynomycolate. Mice immunized with CAII showed a significant increase in the number and size of foci with lymphocytic infiltration in the salivary gland compared with mice immunized with adjuvant alone and untreated mice. In mice immunized with CAII, lymphocytic foci were observed around intercalated and intralobular ducts in the salivary glands, resulting in atrophy and replacement of acinar units. The epithelial cells of salivary ducts adjacent to the lymphocytic foci showed both degenerative and regenerative changes. Similar lymphocytic infiltrations were observed in the pancreas and kidney of a few mice immunized with CAII. Among several mouse strains with different H-2 haplotypes (p, q, r, s, and u), strains bearing H-2s and H-2u were susceptible to CAII-induced sialoadenitis. These results indicate that sialoadenitis induced by the immunization of CAII in mice may serve as a disease model of Sjögren's syndrome and that CAII or its derived peptides in association with the MHC may be one Ag recognized by an autoimmune response in this syndrome.

Induction of experimental autoimmune sialoadenitis by immunization of PL/J mice with carbonic anhydrase II

Experimental autoimmune sialoadenitis was induced in PL/J (H-2u) mice by intradermal immunization with human carbonic anhydrase II (CAII) and adjuvant containing monophosphoryl lipid A and trehalose diorynomycolate. Mice immunized with CAII showed a significant increase in the number and size of foci with lymphocytic infiltration in the salivary gland compared with mice immunized with adjuvant alone and untreated mice. In mice immunized with CAII, lymphocytic foci were observed around intercalated and intralobular ducts in the salivary glands, resulting in atrophy and replacement of acinar units. The epithelial cells of salivary ducts adjacent to the lymphocytic foci showed both degenerative and regenerative changes. Similar lymphocytic infiltrations were observed in the pancreas and kidney of a few mice immunized with CAII. Among several mouse strains with different H-2 haplotypes (p, q, r, s, and u), strains bearing H-2s and H-2u were susceptible to CAII-induced sialoadenitis. These results indicate that sialoadenitis induced by the immunization of CAII in mice may serve as a disease model of Sjögren's syndrome and that CAII or its derived peptides in association with the MHC may be one Ag recognized by an autoimmune response in this syndrome.