Loss of BNIP3 expression is a late event in pancreatic cancer contributing to chemoresistance and worsened prognosis

Altered expression of apoptosis-regulating genes plays an important role in the aggressive growth behavior and chemoresistance of pancreatic ductal adenocarcinoma. In the present study, the hypoxia-inducible proapoptotic gene, BNIP3, was analysed in terms of expression, effect on patient survival, and chemo-responsiveness in pancreatic cancer cell lines. cDNA microarray, real-time light cycler quantitative polymerase chain reaction, laser-capture microdissection, and immunohistochemistry analyses were used to evaluate BNIP3 expression in normal and diseased pancreatic specimens. Modulation of BNIP3 expression was achieved using specific siRNA molecules. The effect of chemotherapeutic agents on pancreatic cancer cells was assessed utilizing 3-(4,5-methylthiazol-2-yl)-2,5-diphenyl-tetrazolium-bromide assays. BNIP3 mRNA levels were 3.0- and 6.3-fold lower in chronic pancreatitis and pancreatic cancer compared to the normal pancreas, respectively. Microdissection analysis confirmed the reduction of BNIP3 expression in pancreatic cancer cells compared to normal duct cells. By immunohistochemistry, BNIP3 was predominantly expressed in the acinar cells of the normal and diseased pancreas. Interestingly, while BNIP3 was undetectable in the cancer cells of 59% of the cases, 75-100% of PanIN2/3 lesions displayed BNIP3 immunoreactivity. Loss of BNIP3 expression correlated with poorer survival of patients (8 vs 14 months for BNIP3 negative vs positive tumors). Hypoxia induced BNIP3 expression in four out of eight pancreatic cancer cell lines, while it was absent under normoxic and hypoxic conditions in the remaining four. Downregulation of BNIP3 resulted in increased resistance to 5-fluoro-uracil and gemcitabine. In conclusion, loss of BNIP3 expression occurs late in pancreatic cancer, contributes to resistance to chemotherapy, and correlates with a worsened prognosis.     

CAM 17.1--a new diagnostic marker in pancreatic cancer.

CAM 17.1-Ab is a recently described monoclonal antibody that detects a mucus glycoprotein with high specificity for intestinal mucus, particularly in the colon, small intestine, biliary tract and pancreas. We investigated the expression and release of CAM 17.1 in pancreatic carcinoma cell lines and tissue specimens of normal pancreas, chronic pancreatitis and pancreatic cancer. CAM 17.1 was weakly expressed on normal ductal cells and chronic pancreatitis, whereas it was overexpressed in pancreatic cancer. Serum analysis using a new enzyme-linked antibody sandwich assay (CAM 17.1/WGA) of patients with chronic pancreatitis, pancreatic cancer or other gastrointestinal cancer and of healthy blood donors revealed a high sensitivity (67%) and excellent specificity (90%) of CAM 17.1/WGA assay in pancreatic cancer. In comparison with the tumour marker CA19-9, the sensitivity of the CAM 17.1/WGA assay was similar to the sensitivity of CA 19-9 (67% and 76%, P = 0.22), whereas the specificity of CAM 17.1/WGA assay was higher than in CA 19-9 (90% compared with 78% in chronic pancreatitis, P > 0.05).     

Relationships and differentially expressed genes among pancreatic cancers examined by large-scale serial analysis of gene expression

Pancreatic adenocarcinoma is among the most fatal of cancers, in part because of late diagnosis and a lack of effective therapies. Comprehensive studies are needed to better understand and address the cellular mechanisms and pathways of tumorigenesis. Serial analysis of gene expression was used to analyze gene expression profiles of pancreatic cancer cell lines, short-term cultures of normal pancreatic ductal epithelium, and primary pancreatic cancer tissue. A total of 294,920 tags representing 77,746 genes in 10 serial analysis of gene expression libraries were analyzed. A pancreatic cancer cell line (Hs766T) that exhibited a "normoid" profile of gene expression was identified. Several genes that may be involved in the fundamental nature of malignant changes in pancreatic ductal epithelium were suggested from those differentially and highly expressed in pancreatic cancer cells as compared with normal epithelium. Some overexpressed genes, such as S100A4, prostate stem cell antigen, carcinoembryonic antigen-related cell adhesion molecule 6, and mesothelin, suggest potential use as diagnostic markers. Others suggest potential novel therapeutic targets.     

Cell lineage markers in human pancreatic cancer

The normal pancreas consists of three major cell types or lineages that share a common embryologic origin from pluripotent endodermal precursors. The type of cell that undergoes neoplastic transformation to form a pancreatic carcinoma is controversial and may influence the phenotype and biologic behavior of the tumor. In this study, immunohistologic techniques were used to determine the cell lineage differentiation expressed in 29 primary exocrine pancreatic adenocarcinomas, five metastatic exocrine pancreatic adenocarcinomas, and five islet cell neoplasma. Specimens of normal pancreas and chronic pancreatitis were used for comparison. The cell lineage markers consisted of monoclonal and polyclonal antibodies against trypsin and lipase (acinar cells); secretory component, carbonic anhydrase II, and pancreatic cancer mucin SPan-1 (ductal cells); and chromogranin-A and somatostatin (islet cells). The expression of carcinoembryonic antigen (CEA) and lysozyme were also determined. This collection of markers allowed the differentiation between acinar, ductal, and islet cells of normal pancreas and chronic pancreatitis specimens. The expression of cell lineage markers in islet cell tumors was homogeneous and restricted to chromogranin-A. In contrast, the expression of these markers in primary and metastatic exocrine pancreatic adenocarcinomas was variable. Reactivity with monoclonal anti-CEA was absent in normal pancreas, and was present in 83% of chronic pancreatitis specimens as well as 90% of exocrine pancreatic adenocarcinomas. In addition, lysozyme reactivity was absent in normal pancreas; however, lysozyme was expressed in one case of chronic pancreatitis, 17 cases of primary carcinoma, and three cases of metastatic carcinoma. These findings support the concept that the original transformed cell type in many pancreatic exocrine carcinomas resemble endodermal "stem cells" that retain the capability of differentiation along more than one cell lineage pathway.     

Serum macrophage inhibitory cytokine 1 as a marker of pancreatic and other periampullary cancers.

PURPOSE: Patients with pancreatic ductal adenocarcinoma usually present with advanced-stage disease and a dismal prognosis. One effective strategy likely to improve the morbidity and mortality from pancreatic cancer would be the identification of accurate, noninvasive diagnostic markers that would enable earlier diagnosis of symptomatic patients and earlier detection of cancer in asymptomatic individuals at high risk for developing pancreatic cancer. In this study, we evaluated serum macrophage inhibitory cytokine-1 (MIC-1) as a marker of pancreatic cancer. EXPERIMENTAL DESIGN: MIC-1 expression in primary pancreatic cancers, intraductal papillary mucinous neoplasms, and pancreatic cancer cell lines was determined using the National Center for Biotechnology Information serial analysis of gene expression database, oligonucleotide microarrays analysis, in situ hybridization, and immunohistochemistry. Serum MIC-1 levels were determined by ELISA in 80 patients with pancreatic adenocarcinomas, in 30 patients with ampullary and cholangiocellular carcinomas, in 42 patients with benign pancreatic tumors, in 76 patients with chronic pancreatitis, and in 97 healthy control subjects. The diagnostic performance of serum MIC-1 as a marker of pancreatic cancer was compared with that of serum CA19-9. RESULTS: Oligonucleotide microarray and serial analysis of gene expression data demonstrated that MIC-1 RNA levels were higher in primary pancreatic cancers, intraductal papillary mucinous neoplasms, and pancreatic cancer cell lines than in nonneoplastic pancreatic ductal epithelium. MIC-1 expression was localized to the malignant epithelium in pancreatic adenocarcinomas by in situ hybridization. MIC-1 protein was expressed in 14 of 16 primary pancreatic adenocarcinomas (88%) by immunohistochemistry and was also expressed in some pancreata affected by pancreatitis but not in normal pancreas. Serum MIC-1 levels were significantly higher in patients with pancreatic ductal adenocarcinoma (mean +/- SD, 2428 +/- 2324 pg/ml) and in patients with ampullary and cholangiocellular carcinomas (2123 +/- 2387 pg/ml) than in those with benign pancreatic neoplasms (940 +/- 469 pg/ml), chronic pancreatitis (1364 +/- 1236 pg/ml), or in healthy controls (546 +/- 262 pg/ml). An elevated serum MIC-1 (defined as 2 SD above the mean for healthy controls) performed as well as CA19-9 (area under the receiver operating characteristic curve, 0.81 and 0.77, respectively), and the combination of MIC-1 and CA19-9 significantly improved diagnostic accuracy (P < 0.05; area under the receiver operating characteristic curve, 0.87; sensitivity, 70%; specificity, 85%). CONCLUSION: Serum MIC-1 measurement can aid in the diagnosis of pancreatic adenocarcinoma.     

Early diagnosis of pancreatic cancer: neutrophil gelatinase-associated lipocalin as a marker of pancreatic intraepithelial neoplasia

Pancreatic cancer is a highly lethal malignancy with a dismal 5-year survival of less than 5%. The scarcity of early biomarkers has considerably hindered our ability to launch preventive measures for this malignancy in a timely manner. Neutrophil gelatinase-associated lipocalin (NGAL), a 24-kDa glycoprotein, was reported to be upregulated nearly 27-fold in pancreatic cancer cells compared to normal ductal cells in a microarray analysis. Given the need for biomarkers in the early diagnosis of pancreatic cancer, we investigated the expression of NGAL in tissues with the objective of examining if NGAL immunostaining could be used to identify foci of pancreatic intraepithelial neoplasia, premalignant lesions preceding invasive cancer. To examine a possible correlation between NGAL expression and the degree of differentiation, we also analysed NGAL levels in pancreatic cancer cell lines with varying grades of differentiation. Although NGAL expression was strongly upregulated in pancreatic cancer, and moderately in pancreatitis, only a weak expression could be detected in the healthy pancreas. The average composite score for adenocarcinoma (4.26+/-2.44) was significantly higher than that for the normal pancreas (1.0) or pancreatitis (1.0) (P<0.0001). Further, although both well- and moderately differentiated pancreatic cancer were positive for NGAL, poorly differentiated adenocarcinoma was uniformly negative. Importantly, NGAL expression was detected as early as the PanIN-1 stage, suggesting that it could be a marker of the earliest premalignant changes in the pancreas. Further, we examined NGAL levels in serum samples. Serum NGAL levels were above the cutoff for healthy individuals in 94% of pancreatic cancer and 62.5% each of acute and chronic pancreatitis samples. However, the difference between NGAL levels in pancreatitis and pancreatic cancer was not significant. A ROC curve analysis revealed that ELISA for NGAL is fairly accurate in distinguishing pancreatic cancer from non-cancer cases (area under curve=0.75). In conclusion, NGAL is highly expressed in early dysplastic lesions in the pancreas, suggesting a possible role as an early diagnostic marker for pancreatic cancer. Further, serum NGAL measurement could be investigated as a possible biomarker in pancreatitis and pancreatic adenocarcinoma.     

胰腺癌组织转录因子GATA-6表达及其意义的探讨

目的:探讨胰腺癌组织GATA-6的表达及其对胰腺癌发生、发展的可能作用及临床意义。方法:采用免疫组化检测33例胰腺癌、15例慢性胰腺炎和6例正常胰腺组织GATA-6蛋白的表达;免疫细胞荧光法检测胰腺癌细胞株Panc-1、BxPC-3和SW1990及正常胰腺导管上皮细胞H6C7的GATA-6蛋白表达情况;Real-time RT-PCR技术检测上述细胞株的GATA-6 mRNA表达;并分析GATA-6与胰腺癌临床病理参数的关系。结果:GATA-6蛋白在胞核中表达,胰腺癌组织GATA-6的阳性表达率(88.9%)显著高于慢性胰腺炎(40.0%)和正常胰腺组织(16.7%),P<0.01,但与性别、年龄、分化程度和临床分期均无显著性相关;3种胰腺癌细胞株均有GATA-6蛋白表达,而正常胰腺导管上皮细胞无表达;3种胰腺癌细胞株GATA-6 mRNA表达也明显高于正常胰腺导管上皮细胞,P<0.05。结论:GATA-6在胰腺癌组织及细胞中呈高表达,提示GATA-6在胰腺癌的发生、发展中可能起一定作用。     

Murine monoclonal antibodies to human pancreatic cancer: specificity and sensitivity

Pancreatic carcinoma (n = 7), pancreatitis tissue (n = 4), normal pancreas tissue (n = 5), colonic adenocarcinoma (n = 4) and in vitro human pancreatic cancer cell lines (n = 6) were studied with the murine monoclonal antibodies (MAbs) 3DS2A, AR1-28, AR2-20, Ca19-9 and CA17-1A to determine their immunohistologic specificity and sensitivity for use as radiolabeled diagnostic imaging agents. Using the avidinbiotin-immunoperoxidase staining technique, MAbs 3DS2A and AR1-28 stained 86 and 100% of pancreatic cancer specimens, respectively. MAbs 3DS2A and AR1-28 are suitable agents for use as radiolabeled diagnostic imaging agents in patients with pancreatic cancer.     

Highly expressed genes in pancreatic ductal adenocarcinomas: a comprehensive characterization and comparison of the transcription profiles obtained from three major technologies

When using gene expression profiling to understand human tumors, one is often confronted with long lists of genes that need to be further categorized into meaningful data. We performed a comprehensive evaluation and comparison of gene expression profiles obtained from pancreatic cancers to determine those genes most differentially expressed and thus with the most promise for translation into clinically useful targets. cDNA was prepared from 50 samples of normal pancreas or duodenal mucosal tissues, 7 samples of chronic pancreatitis, and 39 samples of pancreas cancer tissues or cancer cell lines and hybridized to the complete Affymetrix Human Genome U133 GeneChip set (arrays U133A and U133B) for simultaneous analysis of 45,000 fragments corresponding to 33,000 known genes and 6,000 expressed sequence tags. Genes expressed at levels at least 3-fold greater in the pancreatic cancers as compared with nonneoplastic tissues were identified. Three hundred seventy-seven Affymetrix fragments were identified as having > or = 3-fold expression levels in pancreas cancer specimens as compared with nonneoplastic tissues, corresponding to 234 known genes. Serial analysis of gene expression libraries (http://www.ncbi.nlm.nih.gov/SAGE/) of two normal pancreatic ductal cell cultures (HX and H126) were used to exclude 17 genes with high expression levels in the normal duct epithelium (more than five tags/library). Of the remaining 217 known genes, 75 have been previously reported as highly expressed in pancreatic cancers, while the remaining 142 genes are novel. We used principal components analysis (PCA) to identify the genes among these 217 identified as the most differentially expressed and specific to pancreatic cancer tissues or cell lines. Among the most differentially expressed genes identified by PCA were Mesothelin, Muc4, Muc5A/C, Kallikrein 10, Transglutaminase 2, Fascin, TMPRSS3 and stratifin. The differential expression identified by PCA for these genes indicates they are among the more attractive targets for novel therapeutic targets, tumor markers, or as a means of screening pancreatic cancer samples for information regarding tumor classification or potential therapeutic responses. Our findings were also compared in detail to the previously reported findings of highly expressed genes in other studies of global gene expression in pancreatic cancers. We found that robust changes in gene expression were most often identified by more than one gene expression platform. Forty genes were identified by more than one method (U133 oligonucleotide arrays, cDNA arrays or serial analysis of gene expression), and 6 of these genes were identified by all three methods. Our findings identify a novel set of genes as highly expressed in pancreatic cancer, validate the differential expression of previously reported genes, and provide additional support for those genes most differentially expressed to be translated into clinically useful targets.     

Lex and Ley antigen expression in human pancreatic cancer

Carbohydrate antigens are useful markers for the serological detection of pancreatic cancer. However, data concerning the expression of structurally well-defined carbohydrate antigens in normal and malignant pancreatic tissue is quite limited. The Lex and Leg antigens are closely related carbohydrate antigens synthesized on type 2 blood group oligosaccharide side chains of glycolipids and glycoproteins. Monoclonal antibodies anti-SSEA-1 and AH6 recognize "simple" Lex and Ley epitopes, respectively, regardless of the length of the carrier carbohydrate. Other monoclonal antibodies recognize Lex (FH4), sialyl Lex (FH6, IB9) or Ley (KH1, CC-1, CC-2) carried only by elongated type 2 side chains with or without internal alpha 1,3 fucosyl substitution. The present comparative immunohistochemical study used tissues of normal pancreas, chronic pancreatitis, and pancreatic cancer to determine the normal expression of Lex and Ley antigens in the pancreas and to elucidate any cancer-associated alterations. Lex-related antigens were not expressed in normal pancreas, expressed in only 10-20% of chronic pancreatitis tissues, but expressed in 50-70% of pancreatic cancer tissues. The frequency of Lex-related antigen expression in pancreatic cancer tissues was lowest in poorly differentiated cancers. Within a given specimen, at least three or all four of the Lex recognizing monoclonal antibodies were simultaneously expressed. Unlike Lex antigens, Ley-related antigens were expressed in 32-77% of specimens of normal pancreas, with similar frequencies in specimens of chronic pancreatitis and pancreatic cancer. In normal pancreas, simple Ley was expressed by both ductal and acinar cells, but extended Ley antigens were expressed only by acinar cells. In pancreatic cancer, extended Ley antigen expression was found in less than 10% of poorly differentiated tumors. Coexpression among the Ley-related antigens was less common than with the Lex-related antigens. Also in cancer specimens, simple Lex and simple Lex antigens were often concordantly expressed, whereas extended Lex and extended Ley antigen expression was often discordant. Hyperplastic ducts and ductules associated with pancreatic cancer expressed Lex-related antigens more frequently than morphologically similar lesions associated with chronic pancreatitis. These results demonstrate that Lex-related antigens are cancer-associated determinants in the human pancreas. The discrepant expression between Lex and Ley antigens in these tissues implies altered regulation of fucosyltransferase activity associated with the malignant state.     

Adrenomedullin is induced by hypoxia and enhances pancreatic cancer cell invasion

Adrenomedullin (ADM) is synthesized by different types of cells and acts by binding calcitonin receptor-like receptor (CRLR) and members of the receptor activity-modifying protein (RAMP) family. In this study, the expression and functional role of ADM and its signaling components were investigated in pancreatic adenocarcinoma (PDAC). By QRT-PCR, median mRNA levels of ADM and CRLR were 1.5- and 2.4-fold higher, respectively, in PDAC tissues compared to normal pancreatic tissues. By immunohistochemistry, ADM, CRLR, RAMP1 and RAMP2, but not RAMP3, were expressed in pancreatic cancer cells. ADM serum levels were significantly increased in PDAC patients compared to healthy controls and chronic pancreatitis (CP) patients, with an area under the ROC curve of 0.83 and 0.98, respectively. At a cut-off level of 30.6 ng/ml, the specificity of ADM to differentiate PDAC from controls and CP patients was 85.5 and 83.6%, with a sensitivity of 80 and 100%. All 5 evaluated pancreatic cancer cells lines expressed ADM, CRLR, RAMP1 and RAMP2, whereas RAMP3 was expressed in only 1/5 pancreatic cancer cell lines. ADM was strongly induced by hypoxia and significantly increased invasiveness in 3/5 human pancreatic cancer cells. Blocking of CRLR decreased invasiveness in 4/5 human pancreatic cancer cells. In addition, rADM slightly up-regulated vascular endothelial growth factor secretion in 3/5 cell lines. In conclusion, ADM is induced by hypoxia and over-expressed in PDAC and might therefore serve as a potential tumor marker. Furthermore, ADM increases invasiveness of some pancreatic cancer cells and might influence angiogenesis, suggesting that blocking this pathway might have a therapeutic potential.     

Identification of maspin and S100P as novel hypomethylation targets in pancreatic cancer using global gene expression profiling

DNA hypomethylation is one of the major epigenetic alterations in human cancers. We have previously shown that genes identified as hypomethylated in pancreatic cancer are expressed in pancreatic cancer cell lines, but not in normal pancreatic ductal epithelium and can be reexpressed in nonexpressing cells using 'epigenetic modifying agents' such as DNA methyltransferase inhibitors. To identify additional targets for aberrant hypomethylation in pancreatic cancer, we used oligonucleotide microarrays to screen for genes that displayed expression patterns associated with hypomethylation. This analysis identified a substantial number of candidates including previously reported hypomethylated genes. A subset of eight genes were selected for further methylation analysis, and two cancer-related genes, maspin and S100P, were found to be aberrantly hypomethylated in a large fraction of pancreatic cancer cell lines and primary pancreatic carcinomas. Combined treatment with 5-aza-2'-deoxycytidie and trichostatin A resulted in synergistic induction of maspin and S100P mRNA in MiaPaCa2 cells where both genes were methylated. Furthermore, there was an inverse correlation between methylation and mRNA expression level for maspin and S100P in a large panel of pancreatic cancer cell lines. We also found a significant difference in the methylation patterns of maspin and two previously identified hypomethylated genes (trefoil factor 2 and lipocalin 2) between pancreatic and breast cancer cell lines, suggesting cancer-type specificity for some hypomethylation patterns. Thus, our present results confirm that DNA hypomethylation is a frequent epigenetic event in pancreatic cancer, and suggest that gene expression profiling may help to identify potential targets affected by this epigenetic alteration.     

神经菌毛素在胰腺癌组织及MIA PaCa-Ⅱ细胞系中的表达

目的探讨神经菌毛素（Neuropilin-1，NRP-1）在胰腺导管癌组织及MIA PaCa-Ⅱ胰腺癌细胞系中的表达及意义。方法运用免疫组化和RT-PCR法分别检测在正常胰腺组织、癌旁组织、胰腺癌组织及MIA PaCa-Ⅱ细胞系中Neuropilin-1蛋白及mRNA表达水平。结果蛋白水平：可见正常胰腺组织无表达，癌旁组织轻度表达，而胰腺癌组织及MIA PaCa-Ⅱ胰腺癌细胞中高水平表达。神经组织也可表达Neuropilin-1 mRNA水平见正常胰腺组织呈微量表达，癌旁组织中度表达，而胰腺癌组织及MIA PaCa-Ⅱ胰腺癌细胞中呈高水平表达。结论Neuropilin-1可能与参与了胰腺癌的发生发展，在胰腺癌神经转移中可能起着重要作用。