Use of DNA arrays/microarrays in pancreatic research

In recent years, enormous technical advances in experimental protocols as well as robotic and bioinformatic techniques have allowed DNA array/microarray technology to emerge as the leading technology in the field of functional, disease-related genome analysis. Multiple applications exist for DNA arrays/microarrays including comparative genomic analysis to identify chromosomal imbalances (Matrix-CGH), the study of mutations and genetic polymorphisms, and the study of gene expression (expression profiling). Expression profiling is the most widely used application of DNA array/microarray technology and allows to measure gene expression of thousands of genes simultaneously. The present review describes the basic principles of expression profiling analyses and outlines some applications in pancreatic cancer research.

From acinar cell damage to systemic inflammatory response: current concepts in pancreatitis

Acute pancreatitis represents a local inflammatory disorder with severe systemic consequences. Significant progress in understanding the pathophysiology of acute pancreatitis has been achieved in recent years. However, there is no clear concept about initialization and propagation of the disease both in experimental models and in humans. Furthermore, reliable strategies to evaluate prognosis and perform therapy are still missing. The review focuses on mechanisms originating from acinar cells leading to a systemic inflammatory response in experimental pancreatitis.

Dyspeptic symptoms in middle-aged to old adults: the role of Helicobacter pylori infection, and various demographic and lifestyle factors

OBJECTIVES

To evaluate the role of factors supposed to interfere with the gastric mucosa like Helicobacter pylori, smoking and analgesics in symptom generation in a population-based sample of middle-aged to old.

SUBJECTS

A total of 288 subjects aged 50-85 (mean 65 +/- 7.2) attending a General Science-orientated Continuing Education Programme at the University of Ulm.

METHODS

Helicobacter pylori infection was determined by the 13C-urea breath test. Demographic data, gastrointestinal symptoms and factors supposed to be involved in symptom generation were collected by a standardized questionnaire. The association between various demographic and lifestyle factors with a gastrointestinal symptom score was quantified by odds ratios (ORs) using multiple logistic regression.

RESULTS

Use of nonsteroidal anti-inflammatory drugs (OR=1.2; 95% CI=0.7-2.1) was no risk factor for abdominal symptoms, whereas female sex (OR= 1.6; 95% CI=0.9-2.9) and current smoking (OR= 3.7; 95% CI=0.9-15.4) were associated with a high symptom score. Age 70 years and over was significantly associated with a lower symptom score (OR=0.4; 95% CI=0.2-0.9). However, H. pylori infection was a risk factor for a high symptom score in that age group (OR=4.3; 95% CI=1.2-14.8), whereas no such association (and even a tendency to reduced symptom levels in infected subjects) was observed in younger age groups.

CONCLUSION

The role of H. pylori infection in symptoms may vary by age. The loss of symptoms in the elderly may delay detection of gastroduodenal pathology and appropriate treatment in older adults.

Cross-reactivity of a monoclonal antibody to the amino terminal region of thyrotropin receptor with the serum protein alpha(1)-antitrypsin

In a study designed to detect the presence of soluble, secreted A subunit of thyrotropin hormone receptor (TSHR) in serum, using anti-TSHR murine antibodies (mAbs) and peptide specific antiserum for Western blotting of human serum proteins fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) it was consistently observed that only one mAb, termed A10, reacted strongly with the 53 kd serum protein. The reaction was specific with the mAb A10 only, but not with another mAb or polyclonal antiserum. Furthermore, A10 immunoreactivity was documented in a variety of sera from healthy donors and patients, including patients whose thyroid gland was ablated during treatment for thyroid cancer. This suggests that the A10 cross-reactive protein was not derived from thyroid cells. The A10 cross-reactive protein was purified from normal serum and subjected to N-terminal sequence analysis, which identified the protein as alpha(1)-antitrypsin. Further experiments by enzyme-linked immunosorbent assay (ELISA) and the binding of antibody with deglycosylated or elastase-treated purified serum protein confirmed the cross-reactivity of mAb A10 with alpha(1)-antitrypsin. Alignment of the TSHR amino acid sequence with that of alpha(1)-antitrypsin identified five identical amino acids in a short stretch of residues 34-39 (EEDFRV) in TSHR and residues 205-210 (EEDFHV) in alpha(1)-antitrypsin. Analysis of the structural model of alpha(1)-antitrypsin revealed that these residues were exposed on the surface of alpha(1)-antitrypsin and were accessible for antibodies. Autoantibodies in patients with Graves' disease do not appear to recognize this region of the receptor and hence do not react with serum alpha(1)-antitrypsin.

Ultrasound and magnetic resonance imaging in Crohn's disease: a comparison

The objective of this retrospective study was to compare MRI of the abdomen with ultrasound of the abdomen and gastrointestinal tract in patients with Crohn's disease. Forty-six patients were included in the study. We analyzed the localization of Crohn's lesions, the number of affected bowel segments, the number of stenoses, and the presence of abscesses, fistulae, and any additional findings. Findings were verified by means of one or more of the following: enteroclysis; surgical findings; and colonoscopy. The results show that MRI is superior to ultrasound in the localization of affected bowel segments (sensitivity: MRI 97.5%; US 76%) and in recognizing fistulae (sensitivity: MRI 87%; US 31%), stenoses (sensitivity: MRI 100%; US 58%) and abscesses (sensitivity: MRI 100%; US 89%). Magnetic resonance imaging of the abdomen should be obtained to clarify discrepant clinical and sonographic findings. In addition, despite its higher cost, MRI of the abdomen is justified in patients in whom Crohn's lesions are known or suspected in anatomic areas proximal to the terminal or neoterminal ileum and in cases with suspicion of fistulae and abscesses.

Association analysis of HTR6 and HTR2A polymorphisms in sporadic Alzheimer's disease

In order to identify gene variants related to the serotonergic neurotransmitter system that possibly represent a hereditary risk factor for sporadic Alzheimer's disease (AD), patients suffering from AD and non-demented psychiatric inpatients without symptoms of dementia were genotyped for polymorphisms of HTR6 (267C/T) and HTR2A (-1438G/A). Although there was a tendency toward an increased number of the genotype TT of the 5-HT6 receptor polymorphism in AD patients when compared to controls (2.8% vs. 1.3%), neither this nor the 5-HT2A promoter polymorphism showed significant differences in their genotypic or allelic distribution among patients and controls. These polymorphisms probably do not represent major genetic risk factors of AD. However, further studies including other genetic variants of the serotonergic neurotransmitter system are needed in order to elucidate their role in AD.

Mechanisms of nordihydroguaiaretic acid-induced growth inhibition and apoptosis in human cancer cells

Lipoxygenase metabolites of arachidonic acid can act as growth promoting factors for various cancer cell lines. Here we demonstrate that the 5-lipoxygenase inhibitor nordihydroguaiaretic acid potently inhibits anchorage-independent growth of human pancreatic and cervical cancer cells in soft agar and delays growth of pancreatic and cervical tumours established in athymic mice. Furthermore, nordihydroguaiaretic acid induces apoptosis of these cancer cells in vitro and in vivo. Potential mechanisms mediating these effects of nordihydroguaiaretic acid were examined. Nordihydroguaiaretic acid had no inhibitory effect on growth and survival signals such as tyrosine phosphorylation of the epidermal growth factor receptor or basal and growth factor-stimulated activities of extracellular signal-regulated kinase 1/2, p70(s6k) and AKT but selectively inhibited expression of cyclin D1 in the cancer cells. In addition, treatment with nordihydroguaiaretic acid lead to a disruption of the filamentous actin cytoskeleton in human pancreatic and cervical cancer cells which was accompanied by the activation of Jun-NH(2)-terminal kinase and p38(mapk). Similar effects were obtained by treatment of the cancer cells with cytochalasin D. These results suggest that nordihydroguaiaretic acid induces anoikis-like apoptosis as a result of disruption of the actin cytoskeleton in association with the activation of stress activated protein kinases. In conclusion, nordihydroguaiaretic acid could constitute a lead compound in the development of novel therapeutic agents for various types of cancer.

In vivo alpha(1)-adrenergic lipolytic activity in subcutaneous adipose tissue of obese subjects

The role of alpha(1)-adrenoceptors in lipid mobilization and blood flow was investigated in situ using microdialysis of subcutaneous adipose tissue in severely obese subjects. The lipolysis rate was assessed by determination of interstitial glycerol concentration. The alpha(1)-adrenoceptor agonist norfenefrine caused an increase in glycerol level in adipose tissue that was similar to that observed with the physiologic alpha(1,2)-beta(1)-adrenoceptor agonist norepinephrine, whereas the alpha(1)-adrenoceptor antagonist urapidil showed no effect on basal lipolysis rate. However, the enhanced glycerol concentration due to norfenefrine and norepinephrine was suppressed in the presence of urapidil. The beta-adrenoceptor antagonist propranolol showed no effect on norfenefrine-stimulated glycerol outflow. Blood flow was assessed using the ethanol escape technique. Perfusion with norfenefrine decreased blood flow, whereas urapidil enhanced blood flow significantly. Despite the increase in blood flow, the basal interstitial glycerol concentration remained unchanged. Although norfenefrine at high concentrations could inhibit the urapidil-induced increase in blood flow, the norfenefrine-induced glycerol output was not affected. These results demonstrate that alpha(1)-adrenoceptors are involved in regulation of lipolysis rate and microcirculation of adipose tissue. However, the observed changes in local blood flow were not related to glycerol output.

[Cost measurement based on a cost diary in patients with inflammatory bowel disease]

OBJECTIVE

Cost diaries administered by patients have been used as a method to measure costs for different diseases. Our aim was to test the application of a patient cost diary in patients with inflammatory bowel disease (IBD) and to measure disease specific resource utilization and costs.

PATIENTS AND METHODS

A specific patient cost diary for IBD was developed and tested in a prospective pilot study. 105 outpatients with IBD of a University Hospital agreed to participate over a 4 week follow-up period. They were asked to report weekly their use of medical care and costs related to their illness. Visits to health care providers, hospitalizations, drug use, costs due to absence from paid and unpaid work, travel costs as well as out-of-pocket expenses were considered.

RESULTS

The response rate was 90 %. Almost 70 % of the patients estimated the diary as easy to fill in. Compared with other data sources, the cost measurement using the cost diary showed good agreement regarding costs of drug therapy and outpatient hospital treatment. Mean costs due to illness were estimated to be 1,500 Euro per 4 weeks. This corresponds to total costs of about 20,000 Euro per year of care. 69 % of total costs were indirect costs due to illness-related absence from work, days of inactivity at home, and early retirement. Direct health care and direct non health care costs (e. g. travel costs) were responsible for 27 % and 4 % of costs, respectively.

DISCUSSION AND CONCLUSION

The presented instrument offers a suitable and practical method of assessing IBD-related resource utilization. The prospectively obtained data for direct medical and non medical, as well as indirect costs allow a cost measurement from the societal perspective. The presented cost diary can be used for measuring costs for economic evaluations of medical interventions.

Ganglioside reactive antibodies of IgG and IgM class in sera of patients with differentiated thyroid cancer

We searched for the presence of ganglioside reactive antibodies in sera of patients with differentiated thyroid cancer (DTC). Sera were screened by ELISA with plates coated with GM3(NeuAc), GM3(NeuGc), GM2, GM1, FucGM1, GD3, GD1a or GD1b gangliosides. Ganglioside reactive antibodies were detected more frequently in sera of patients with DTC than in sera of healthy persons, in keeping with the possibility of autoimmunization during carcinogenesis. Antibodies of IgM and IgG classes reactive with FucGM1 occurred most often. However, the infrequent occurrence of ganglioside reactive antibodies, their low titer and lack of correlation between their presence and clinical condition of the patients indicate that determination of these antibodies has no diagnostic value in DTC.

[Evaluation of gene expression for cag A in strains of Helicobacter pylori colonizing gastric mucosa]

Recent studies indicate that infection with H. pylori strains expressing cytotoxic proteins such as cag A or vac A is an important risk factor for the development of chronic atrophic gastritis, gastric cancer, or MALT-type lymphoma. The aims of this study were: 1) to develop an RT-PCR assay for the analysis of cag A gene expression in H. pylori present in gastric mucosa specimens obtained during gastroendoscopy; 2) to examine with this method the correlation between the presence of cag A gene and its expression. The study was performed in 82 patients (40 females and 42 males). cag A DNA was detected in gastric mucosa in 42 patients, among them in 17 out of 35 with dyspepsia, in 14 out of 25 with peptic ulcer disease, in 2 out of 10 with gastric cancer and in 8 out of 11 with a family history of gastric cancer (Tab. 1). cag A gene expression could not be confirmed in only two cases positive for cag A DNA (both patients had a family history of gastric cancer, Fig. 1). The results of this study indicate that the RT-PCR assay is a useful tool for the molecular diagnostics of H. pylori infection. Further studies are needed to explain the role of cag A gene in the pathogenesis of peptic ulcer and gastric tumors.

Lack of association between Gly460Trp polymorphism of alpha-adducin gene and salt sensitivity of blood pressure in Polish hypertensives

BACKGROUND

Previous studies have suggested that alpha-adducin (alpha-ADD) polymorphism may identify patients with a salt-sensitive form of hypertension.

AIM

To investigate the association between Gly460Trp polymorphism of alpha-ADD and the pattern of blood pressure response to subacute (1 week) salt loading and depletion in young adult thin Polish hypertensives.

METHODS

The study group consisted of 44 subjects with salt-sensitive hypertension (SS) and 24 subjects with non-salt-sensitive hypertension (SR). Genomic DNA isolated from peripheral blood leukocytes was amplified by PCR method with primers flanking the polymorphic region. The mismatch near to 3'-end of the upstream primer was introduced to create a Nla III restriction site in Trp 460 allele. In addition, excreted fraction of filtered sodium (FENa), plasma renin activity (PRA) and plasma concentrations of aldosterone (ALDO) were determined on normal, low and high salt diets.

RESULTS

FENa on normal or high salt diets were significantly lower in the SS hypertensives as compared with the SR patients. PRA in SS group was also significantly lower as compared with results in SR group, but only on high salt diet. No significant difference was detected in frequencies of genotypes and alleles of alpha-ADD gene between SS and SR subjects. An additional analysis with regard to genotype (Gly/Gly vs. Gly/Trp+Trp/Trp) showed no significant difference in changes of blood pressure as well as in results of laboratory investigations.

CONCLUSION

Our results suggest lack of association between Gly460Trp polymorphism of alpha-adducin gene and salt sensitivity of blood pressure in Polish hypertensives.

Neurotrophin and GDNF expression increases in rat adrenal glands during experimental colitis

OBJECTIVES

Neurotrophins and GDNF have been recently recognized as important local regulators of inflammatory processes of the gut.

RESULTS

We now demonstrate that experimental TNBS-colitis is associated with the increased expression of neurotrophins and GDNF in the adrenal glands. In histological sections of the adrenals from untreated control animals, faint immunolabeling for BDNF, NT-3 and NGF was detectable in the adrenal cortex, with some additional labeling for NGF over the adrenal medulla, whereas GDNF immunolabeling was confined to the adrenal medulla. Induction of TNBS-colitis markedly increased NGF, BDNF, and NT-3 expression within the adrenal cortex after 8 h. NGF declined to basal levels after 7 days. In case of BDNF and NT-3 basal expression levels were reached after 14 days. GDNF expression was robustly upregulated in the adrenal medulla 8 h after induction of colitis and stayed elevated for up to 14 days.

CONCLUSION

Together these observations suggest that neurotrophins and GDNF might act as local modulators of components of the HPA-axis during peripheral inflammation.

Small cell lung cancer is not associated with the presence of anti-fucosyl-GM1 ganglioside autoantibodies reactive in immunoenzymatic test

The characteristic feature of small cell lung cancer carcinoma (SCLC) is the aberrant expression and abundant presentation of fucosyl-GM1 ganglioside (FucGM1). In the present study we searched for the presence of anti-FucGM1 ganglioside, as well as anti-GM1, GM2 and GD3 ganglioside autoantibodies in the sera of patients with SCLC and as a control, in sera of patients with renal cell cancer (RC) and healthy blood donors. The autoantibodies against FucGM1 were present at low titer in only three of 36 SCLC patients, and with similar titer in two of 36 RC patients and four of 36 healthy controls. Likewise, the autoantibodies against GM2 and GM3 gangliosides were found only sporadically and with the same titer and frequency in cancer patients as in healthy persons. Anti-GD3 autoantibodies could not be detected in any of the screened sera.

p300 acts as a transcriptional coactivator for mammalian Notch-1

Notch-1 belongs to a family of transmembrane receptor proteins that direct the decisions as to various cell fates. After ligand binding, a proteolytic cleavage step occurs and the intracellular part of Notch-1, Notch-1-IC, translocates into the nucleus, where it targets the DNA binding protein RBP-J kappa/CBF1. RBP-J kappa mediates repression through recruitment of a histone deacetylase-containing complex. The Notch-1-IC/RBP-J kappa complex overcomes repression and activates the transcription of Notch target genes. We have identified a novel domain in Notch-1-IC, the EP domain, which is indispensable for full transcriptional activation. This transactivation domain is localized adjacent to the ankyrin repeats of Notch-1-IC. In cotransfection experiments, Notch-1-IC-mediated transcriptional activation was inhibited by E1A12S and p53, two proteins, which interfere with the function of the common coactivator p300. Protein-protein interaction assays demonstrated the association of Notch-1-IC and the CH3 region of p300. In addition, the interaction of mammalian Notch-1-IC with p300 was destabilized after deletion of the EP domain of Notch-1-IC. Based on physical interaction with Notch-1-IC and coactivator functions of p300, we propose a model for Notch-1-mediated gene regulation via p300.

Oxidized low-density lipoproteins bind to the scavenger receptor, CD36, of hepatic stellate cells and stimulate extracellular matrix synthesis

Cumulating evidence suggests that oxidative stress resulting in lipid peroxidation and protein modification is involved in the pathogenesis of chronic liver injury and fibrogenesis. We investigated the effects of oxidized low-density lipoproteins (oxLDL) on collagen and fibronectin synthesis of cultured human and rat hepatic stellate cells (HSC). As shown on protein and mRNA levels, oxLDL dose-dependently stimulated the synthesis of collagen types I and III and fibronectin of cultured HSC. The effect was biphasic, with a maximum between 5 and 25 microg/mL oxLDL (c-fibronectin concentration in HSC supernatants increased 3.9-fold; collagen type I increased 4-fold). Higher oxLDL concentrations were cytotoxic. LDL modified with malondialdehyde (MDA) was not toxic, but stimulated extracellular matrix synthesis as well. As demonstrated by immunofluorescence microscopy (double staining of CD36 and iso-alpha-smooth muscle actin [iso-alpha-sm actin]), immunoblot, and reverse-transcription polymerase chain reaction (RT-PCR), respectively, cultured human HSC express the oxLDL receptor, CD36 (glycoprotein IIIb). Colocalization of CD36 and iso-alpha-sm actin on sinusoidal lining cells was further demonstrated using sections of human fibrotic liver. Preincubation of cultured human HSC with the monoclonal antibody, OKM5, known to block CD36-mediated oxLDL uptake, resulted in a reduction of the oxLDL-stimulated collagen type I synthesis by 56%. In summary, our results demonstrate that low concentrations of modified lipoproteins (oxLDL and MDA-LDL) represent fibrogenic mediators that bind to CD36 and stimulate matrix synthesis of HSC.

Integrin-mediated differentiation of a pancreatic carcinoma cell line is independent of FAK or MAPK activation levels

INTRODUCTION

The extracellular matrix (ECM) plays a salient role for proliferation and differentiation of epithelial cells. It was demonstrated that cell-ECM interactions mediated through integrins control gene expression and the tissue phenotype even in malignant tumors. Alterations of the ECM are a key feature of ductal adenocarcinoma of the pancreas.

AIMS

To examine the role of integrins and related signaling events for differentiation.

METHODOLOGY AND RESULTS

We established an in vitro model for ECM-induced differentiation of poorly differentiated pancreatic carcinoma cells and found that a specific pattern of ECM proteins resembling basal laminas (matrigel) induces differentiation of the PaTu-II pancreatic carcinoma cell line to a ductal phenotype. Both beta1- and beta4-integrins are required for cellular differentiation. Integrin-associated signaling events include activation of pp125 focal adhesion kinase (FAK) and mitogen-activated protein kinases (MAPKs) such as extracellular signal-regulated kinases (ERKs) and c-Jun NH2-terminal kinases (JNKs). However, beta1- and beta4-integrin-mediated differentiation of PaTu-II cells was independent from FAK, ERK, and JNK activation levels. Inhibition of MAPK kinases by PD98059 led to a reduction of proliferation but did not interfere with cellular differentiation of PaTu-II cells on matrigel.

CONCLUSION

The integrin-mediated differentiation of PaTu-II cells is regulated and maintained through FAK- and MAPK-independent signal transduction pathways.

Acute pancreatitis

The pathophysiologic concept of acute pancreatitis focuses on early events inside acinar cells such as activation of trypsin. Despite significant progress in the understanding of molecular events in experimental pancreatitis, knowledge of these mechanisms has not yet been translated into therapeutic strategies useful in humans. A single morphologic or laboratory marker reliably predicting the individual course of acute pancreatitis still awaits discovery. The clinical outcome of acute pancreatitis is dependent on the presence of necrosis and systemic complications. The extent of the systemic inflammatory response to local pancreatitis seems to be the rate-limiting step. Several mechanisms shed light on the interconnectivity between intra-acinar protease activation and immunoregulatory processes. Deciphering these cell biologic connections has already had an impact on the clinical management of patients and the identification of prognostic markers in human disease. However, further investigations of pancreatic pathophysiology are needed to initiate novel therapeutic strategies.

Biglycan is overexpressed in pancreatic cancer and induces G1-arrest in pancreatic cancer cell lines

BACKGROUND & AIMS

Biglycan (PG-I), a component of the extracellular matrix (ECM), is overexpressed in pancreatic cancer. To determine possible matrix-tumor interactions, we investigated the effects of PG-I on pancreatic cancer.

METHODS

PG-I expression in cell lines and tissue samples was examined by Northern blot and immunofluorescence. The effect of PG-I on proliferation was determined by measuring activity of Ras, ERK, Rb, [(3)H]-thymidine incorporation, and cell cycle analysis. Expression of cyclin A, B1, D1, E1, G1, PCNA, p21, and p27 was analyzed by Northern and Western blots.

RESULTS

PG-I was overexpressed in the ECM of pancreatic cancer samples compared with normal pancreas or chronic pancreatitis tissues. Addition of transforming growth factor (TGF)-beta induced PG-I expression in HFL and HFFF2 fibroblasts as well as in the pancreatic cancer cell line PANC-1. PG-I inhibited growth of both TGF-beta-responsive and TGF-beta-unresponsive pancreatic cancer cells by inducing G1-arrest, which is accompanied by an increase of p27 and reduction of cyclin A and proliferating cell nuclear antigen. Furthermore, endogenous Ras and ERK activation was partly reduced by PG-I in vitro.

CONCLUSIONS

The ECM protein PG-I inhibits growth by arresting pancreatic cancer cells in G1 and may be part of a host defense mechanism aimed at slowing down pancreatic tumor progression.

Is a preoperative multidiagnostic approach to predict surgical resectability of periampullary tumors still effective?

BACKGROUND

Multimodality staging is recommended in patients with periampullary tumors to optimize preoperative determination of resectability. We investigated the potency of currently used diagnostic procedures in order to determine resectability.

METHODS

Ninety-five consecutive patients with periampullary tumors prehospitally staged resectable underwent preoperative diagnostic tests: helical-computed tomography (CT) with maximum intensity projection of arterial vessels (MIP), magnetic resonance imaging (MRI), magnetic resonance cholangiopancreaticography (MRCP), endoscopic ultrasonography (EUS), endoscopic retrograde cholangiopancreaticography (ERCP), digital subtraction angiography (DSA), and positron emission tomography (PET). Diagnoses were verified by surgery and histopathology.

RESULTS

In 45 patients with benign and 50 patients with malignant periampullary tumors sensitivity for tumor diagnosis was 89% to 96% in CT, MRI, EUS, and PET. Small tumors were best diagnosed by EUS (100%). Diagnosis of malignancy was made with 85% (EUS), 83% (CT), 82% (PET), and 72% (MRI) accuracy. Arterial vessel infiltration was best predicted by CT/MIP with an accuracy of 85%. For venous vessel infiltration MRI reached 85% accuracy. Accuracy rates for local nonresectability were 93% (EUS), 92% (MRI), and 90% (CT). Two and 4 of 8 patients with distant metastases were identified by CT and PET, respectively. The correct diagnosis of malignancy and determination of resectability was made by CT in 71% and by MRI in 70%. Biliary stenting reduced accuracy of CT diagnosis of malignancy from 88% to 73%.

CONCLUSIONS

CT obtained before stenting was the single most useful test, providing correct diagnosis in 88% and resectability in 71% of patients. If no tumor is depicted in CT, EUS should be added. Uncertain venous vessel infiltration can be verified by MRI or EUS. Angiography should no longer be a routine diagnostic procedure. Equivocal tumors or possible metastasis may be further examined with PET.

Claudin-4: a new target for pancreatic cancer treatment using Clostridium perfringens enterotoxin

BACKGROUND & AIMS

Recently, several members of the claudin family have been identified as integral constituents of tight junctions. Using expression profiling, we previously found claudin-4 to be overexpressed in pancreatic cancer. Because claudin-4 has been described as a receptor for the cytotoxic Clostridium perfringens enterotoxin (CPE), we investigated the effect of CPE on pancreatic cancer cells.

METHODS

Expression of claudin-4 was analyzed by Northern blots. In vitro toxicity of CPE was determined by trypan blue exclusion and the (86)Rb-release assay. The in vivo effect of CPE was studied in claudin-4-expressing nude mouse xenografts of the Panc-1 cell line.

RESULTS

Expression analyses showed that claudin-4 was overexpressed in most pancreatic cancer tissues and cell lines and several other gastrointestinal tumors. CPE led to an acute dose-dependent cytotoxic effect, restricted to claudin-4-expressing cells and dependent on claudin-4 expression levels. Furthermore, transforming growth factor beta was identified as a negative modulator of both claudin-4 expression and susceptibility to CPE. In vivo, intratumoral injections of CPE in Panc-1 xenografts led to large areas of tumor cell necrosis and significant reduction of tumor growth.

CONCLUSIONS

Our findings suggest that targeting claudin-4-expressing tumors with CPE represents a promising new treatment modality for pancreatic cancer and other solid tumors.