Healthy Pancreatic Tissue Research Articles

Preoperative Glucagon-like peptide-1 receptor imaging reduces surgical trauma and pancreatic tissue loss in insulinoma patients: a report of three cases.

BackgroundInsulinomas are rare tumors, in the majority of cases best treated by surgical resection. Preoperative localization of insulinoma is challenging. The more precise the preoperative localization the less invasive and safer is the resection. The purpose of the study is to check the impact of a new technique to localize insulinoma on the surgical strategy.FindingsWe present exact preoperative localization with Glucagon-like peptide-1 receptor (GLP-1R) imaging. This allows a more precise resection thereby reducing surgical access trauma, loss of healthy pancreatic tissue and increasing safety and quality of the surgical intervention.ConclusionWith the help of precise preoperative localization of insulinoma with GLP-1R imaging the surgeon is able to minimize the amount of resected healthy pancreatic tissue. We hypothesize that GLP-1R imaging will become a preoperative diagnostic tool to be used for many patients scheduled for open or laparoscopic insulinoma resection.

Novel targeting methods for pancreatic cancer. (TECH2P.914)

Abstract Pancreatic cancer is the fourth leading cause of cancer deaths in the United States and one of the most difficult-to-treat cancers. Despite advances in chemotherapy, 5-year survival following surgical resection is only 23% in specialized pancreatic surgery centers. A major stumbling block for these and other cancer treatments is a way to efficiently deliver therapeutics to the target cells. Thus, we have identified high affinity molecular targeting molecules unique to an individual pancreatic cancer, which were generated utilizing a high throughput system using fresh surgical specimens along with phage display to develop novel small chain variable fragments (scFv). Here we present the characterization of two scFv molecules identified, through which we demonstrate by ELISA and BioLayer Interferometry that our scFv bind with high specificity to the neoplasm from which they were derived, while remaining minimally reactive to healthy pancreatic tissue. In addition, we have engineered these scFV to be assembled into a homotrimeric alpha-helical coiled coil using a novel platform in order to retain its multimeric nature. Future studies will assess the ability of these scFv to home to the original neoplasm using our established patient-derived tumor xenograft models whereby the human tumor is grown in NOD/SCID mice. Together these data will determine whether screening individual neoplasms using phage display can be used to develop scFv as personalized targeting molecules.

Expression and Activity of Nadph Oxidase 4 (Nox4) is Related to Antiapoptotic Activity of Human Pancreatic Adenocarcinoma Cells

Pancreatic adenocarcinoma is one of the most aggressive human malignancies with high mortality rates. Low survival rates are due to late diagnosis at advanced stages of the disease. High invasiveness and chemoresistance of pancreatic adenocarcinoma at least partially could be related to the antiapoptotic activity of intracelular ROS generated by Nox4. There are only few studies about Nox4 expression in pancreatic cancer, yet Nox4 is believed to be relevant antiapoptotic factor in pancreatic cancer cells. In this study we have determined the expression of Nox4 in human pancreatic tissue at both protein and mRNA levels. We compared how Nox4 is overexpressed in pancreatic cancer in comparison to human healthy adjacent and healthy donor pancreatic tissue. We have also identified the effect of ROS formation in MiaPaca-2 and Capan-2 cells under treatment with NADPH oxidase inhibitors DPI and apocynin. Our results showed that DPI and apocynin inhibited ROS formation. Moreover, it decreased viability of pancreatic cancer cells and induced apoptosis as well. Result confirms ROS being responsible for antiapoptotic activity of pancreatic cancer cells. These findings point out to NADPH oxidases being a potential terapeutic targets in treatment of cancer.

New Blocking Antibodies against Novel AGR2-C4.4A Pathway Reduce Growth and Metastasis of Pancreatic Tumors and Increase Survival in Mice.

Anterior gradient 2 (AGR2) promotes cancer growth, metastasis, and resistance to therapy via unknown mechanisms. We investigated the effects of extracellular AGR2 signaling through the orphan glycosylphosphatidylinositol-linked receptor C4.4A in pancreatic ductal adenocarcinoma (PDAC). Proliferation, migration, invasion, and apoptosis were measured using colorimetric, Boyden chamber, and FACS analyses. We developed blocking mAbs against AGR2 and C4.4A and tested their effects, along with siRNAs, on cancer cell functions and on orthotopic tumors in nude mice. Extracellular AGR2 stimulated proliferation, migration, invasion, and chemoresistance of PDAC cell lines. AGR2 interacted with C4.4A in cell lysates and mixtures of recombinant proteins. Knockdown of C4.4A reduced migration and resistance to gemcitabine. PDAC tissues, but not adjacent healthy pancreatic tissues, expressed high levels of AGR2 and C4.4A. AGR2 signaling through C4.4A required laminins 1 or 5 and integrin β1. Administration of antibodies against AGR2 and C4.4A reduced growth and metastasis and caused regression of aggressive xenograft tumors, leading to increased survival of mice. These data support a model in which AGR2 binds and signals via C4.4A in an autocrine loop and promotes the growth of pancreas tumors in mice. Blocking mAbs against AGR2 and C4.4A may have therapeutic potential against PDAC.

Loss of Somatostatin Receptor Subtype 2 Promotes Growth of KRAS-Induced Pancreatic Tumors in Mice by Activating PI3K Signaling and Overexpression of CXCL16

The KRAS gene is mutated in most pancreatic ductal adenocarcinomas (PDAC). Expression of this KRAS oncoprotein in mice is sufficient to initiate carcinogenesis but not progression to cancer. Activation of phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) is required for KRAS for induction and maintenance of PDAC in mice. The somatostatin receptor subtype 2 (sst2) inhibits PI3K, but sst2 expression is lost during the development of human PDAC. We investigated the effects of sst2 loss during KRAS-induced PDAC development in mice. We analyzed tumor growth in mice that expressed the oncogenic form of KRAS (KRAS(G12D)) in pancreatic precursor cells, as well as sst2+/- and sst2-/-, and in crossed KRAS(G12D);sst2+/- and KRAS(G12D);sst2-/- mice. Pancreatic tissues and acini were collected and assessed by histologic, immunoblot, immunohistochemical, and reverse-transcription polymerase chain reaction analyses. We also compared protein levels in paraffin-embedded PDAC samples from patients vs heathy pancreatic tissues from individuals without pancreatic cancer. In sst2+/- mice, PI3K was activated and signaled via AKT (PKB; protein kinase B); when these mice were crossed with KRAS(G12D) mice, premalignant lesions, tumors, and lymph node metastases developed more rapidly than in KRAS(G12D) mice. In crossed KRAS(G12D);sst2+/- mice, activation of PI3K signaling via AKT resulted in activation of nuclear factor-κB (NF-κB), which increased KRAS activity and its downstream pathways, promoting initiation and progression of neoplastic lesions. We found this activation loop to be mediated by PI3K-induced production of the chemokine CXCL16. Administration of a CXCL16-neutralizing antibody to KRAS(G12D) mice reduced activation of PI3K signaling to AKT and NF-κB, blocking carcinogenesis. Levels of CXCL16 and its receptor CXCR6 were significantly higher in PDAC tissues and surrounding acini than in healthy pancreatic tissues from mice or human beings. In addition, expression of sst2 was progressively lost, involving increased PI3K activity, in mouse lesions that expressed KRAS(G12D) and progressed to PDAC. Based on analyses of mice, loss of sst2 from pancreatic tissues activates PI3K signaling via AKT, leading to activation of NF-κB, amplification of oncogenic KRAS signaling, increased expression of CXCL16, and pancreatic tumor formation. CXCL16 might be a therapeutic target for PDAC.

Diffusion tensor magnetic resonance imaging of the pancreas.

PurposeTo develop a diffusion-tensor-imaging (DTI) protocol that is sensitive to the complex diffusion and perfusion properties of the healthy and malignant pancreas tissues.Materials and MethodsTwenty-eight healthy volunteers and nine patients with pancreatic-ductal-adenocacinoma (PDAC), were scanned at 3T with T2-weighted and DTI sequences. Healthy volunteers were also scanned with multi-b diffusion-weighted-imaging (DWI), whereas a standard clinical protocol complemented the PDAC patients’ scans. Image processing at pixel resolution yielded parametric maps of three directional diffusion coefficients λ1, λ2, λ3, apparent diffusion coefficient (ADC), and fractional anisotropy (FA), as well as a λ1-vector map, and a main diffusion-direction map.ResultsDTI measurements of healthy pancreatic tissue at b-values 0,500 s/mm2yielded: λ1 = (2.65±0.35)×10−3, λ2 = (1.87±0.22)×10−3, λ3 = (1.20±0.18)×10−3, ADC = (1.91±0.22)×10−3 (all in mm2/s units) and FA = 0.38±0.06. Using b-values of 100,500 s/mm2 led to a significant reduction in λ1, λ2, λ3 and ADC (p<.0001) and a significant increase (p<0.0001) in FA. The reduction in the diffusion coefficients suggested a contribution of a fast intra-voxel-incoherent-motion (IVIM) component at b≤100 s/mm2, which was confirmed by the multi-b DWI results. In PDACs, λ1, λ2, λ3 and ADC in both 0,500 s/mm2 and 100,500 s/mm2 b-values sets, as well as the reduction in these diffusion coefficients between the two sets, were significantly lower in comparison to the distal normal pancreatic tissue, suggesting higher cellularity and diminution of the fast-IVIM component in the cancer tissue.ConclusionDTI using two reference b-values 0 and 100 s/mm2 enabled characterization of the water diffusion and anisotropy of the healthy pancreas, taking into account a contribution of IVIM. The reduction in the diffusion coefficients of PDAC, as compared to normal pancreatic tissue, and the smaller change in these coefficients in PDAC when the reference b-value was modified from 0 to 100 s/mm2, helped identifying the presence of malignancy.

Epiplakin deficiency aggravates murine caerulein-induced acute pancreatitis and favors the formation of acinar keratin granules.

Epiplakin, a member of the plakin protein family, is exclusively expressed in epithelial tissues and was shown to bind to keratins. Epiplakin-deficient (EPPK−/−) mice showed no obvious spontaneous phenotype, however, EPPK−/− keratinocytes displayed faster keratin network breakdown in response to stress. The role of epiplakin in pancreas, a tissue with abundant keratin expression, was not yet known. We analyzed epiplakin’s expression in healthy and inflamed pancreatic tissue and compared wild-type and EPPK−/− mice during caerulein-induced acute pancreatitis. We found that epiplakin was expressed primarily in ductal cells of the pancreas and colocalized with apicolateral keratin bundles in murine pancreatic acinar cells. Epiplakin’s diffuse subcellular localization in keratin filament-free acini of K8-deficient mice indicated that its filament-associated localization in acinar cells completely depends on its binding partner keratin. During acute pancreatitis, epiplakin was upregulated in acinar cells and its redistribution closely paralleled keratin reorganization. EPPK−/− mice suffered from aggravated pancreatitis but showed no obvious regeneration phenotype. At the most severe stage of the disease, EPPK−/− acinar cells displayed more keratin aggregates than those of wild-type mice. Our data propose epiplakin to be a protective protein during acute pancreatitis, and that its loss causes impaired disease-associated keratin reorganization.

Autophagy is needed for the growth of pancreatic adenocarcinoma and has a cytoprotective effect against anticancer drugs

Background and aimAutophagy is a regulated process of degradation and recycling of cellular constituents. The role of autophagy in pancreatic cancer is still not clear. Some studies indicate that in pancreatic cancer autophagy exerts cytoprotective effects, whereas others suggest that autophagy positively contributes to cell death by enhancing cytotoxicity of anticancer drugs. The aim of this study was to investigate the role of autophagy in pancreatic cancer, and to provide insights into new strategies for treatment. Materials and methodsPancreatic cancer cell lines PANC-1 and BxPC-3 were treated with anticancer drugs (5-fluorouracil or gemcitabine) alone and in combination with autophagy inhibitors (chloroquine or wortmannin). Biopsy samples were retrieved from patients from pancreatic normal tissue and adenocarcinoma. Western blot of microtubule-associated protein 1 light chain 3 (LC3)-II was performed to investigate the degree of autophagy and cell proliferation was assessed by a crystal violet assay. ResultsAutophagy was active in PANC-1 cells under basal conditions. Autophagy was significantly induced in pancreatic ductal adenocarcinoma compared to healthy pancreatic tissue in patients. Inhibition of autophagy by chloroquine suppressed the growth of PANC-1 and BxPC-3. Autophagy was markedly increased after treatment with 5-fluorouracil or gemcitabine. Inhibition of autophagy by chloroquine potentiated the inhibition of cell proliferation of PANC-1 and BxPC-3 by 5-fluorouracil and gemcitabine. ConclusionsOur results with pancreatic cancer cell lines and human pancreatic adenocarcinoma suggest that autophagy contributes to pancreatic cancer cell growth. Autophagy has a cytoprotective effect against 5-fluorouracil and gemcitabine in pancreatic cancer cells. Combination therapy of these anticancer drugs and chloroquine should be investigated.

Fibrosis and Pancreatic Lesions

Stroma reaction leading to fibrosis is the most characteristic histopathological feature of both pancreatic carcinoma and chronic pancreatitis with increased fibrosis compared with healthy pancreatic tissue and further increased fibrosis during radiochemotherapy. Recent studies using intravoxel incoherent motion-derived parameters did not show differences for structural diffusion constant D between these 2 diseases. The aim of this study was to verify the hypothesis that D correlates with the histopathological grade of fibrosis in pancreatic lesions. We included 15 patients with histopathologically proven pancreatic carcinoma and 9 patients with histopathologically proven focal chronic pancreatitis. Diffusion-weighted magnetic resonance imaging was performed using 10 b values between 25 and 800 s/mm² before surgery. We calculated the apparent diffusion coefficient and the intravoxel incoherent motion-derived parameters D and f within tumors and focal chronic pancreatitis. The resected tissue was evaluated with regard to the grade of fibrosis. Fourteen patients were found to have moderate fibrosis and 10 patients had severe fibrosis. The difference between the D values for the moderate and severe fibrosis was significant with mean (SD) D value of 1.02 × 10⁻³ (0.48 × 10⁻³ mm/s) and mean (SD) D of 1.22 × 10⁻³ (0.76 × 10⁻³) mm²/s. There were no significant differences for the f and ADC values. Contrary to our hypothesis, D rises from moderate to severe fibrosis. It seems that cellular complexes surrounded by fibrosis provide more structural limitations than does fibrosis alone. Our data suggest that D is not intuitively related to the degree of fibrosis. Compared with healthy tissue, D is reduced in moderate fibrosis but increases when severe fibrosis is present.

The role of iNOS in beta cell destruction in diabetes

Nitric oxide (NO) is a signaling molecule which can play a role in pancreatic pathophysiology and is involved in regulation of beta cell mass. Nitric oxide is produced by the enzyme NO synthase (NOS). Nitric oxide synthase has three major isoforms; one of them, inducible NOS (iNOS) is expressed in almost every cell type. In healthy pancreatic tissues, iNOS immunoreactivity was demonstrated in islet of Langerhans cells, centroacinar cells and ductal cells. In addition, induction of islet iNOS was also demonstrated in acute pancreatitis, and type 1 and type 2 diabetes mellitus. When pancreatic beta cells come up against inflammatory cytokines, lipid stress or hyperglycemia, iNOS activation increases and the resulting high concentrations of NO produced causes cell dysfunction or death and therefore the insulin secretion is inhibited. However, the precise mechanism of iNOS expression and the occurrence of resulting beta-cell damage have not been truly clarified yet. Diabetogenesis cannot be completely prevented with iNOS inhibitors. Physiological and pathological limits of iNOS expression should be established and the mechanism of the damage on beta cells by over-expression should be defined and prevented.

Exploring the role of Mycobacterium avium subspecies paratuberculosis in the pathogenesis of type 1 diabetes mellitus: a pilot study

BackgroundAlthough the etiology of Type 1 Diabetes mellitus (T1DM) has not been determined, genetic polymorphism in key genes, including SLC11A1, and association with Mycobacterium avium subspecies paratuberculosis (MAP) have been reported. We hypothesize that molecular mimicry between MAP Heat shock protein 65 K (Hsp65) and human Glutamic Acid Decarboxylase 65 K (GAD65) may be the trigger leading to autoimmune destruction of beta cells in patients exposed to MAP.MethodPeptide sequences of MAP Hsp65 and human GAD65 were investigated for amino acid sequence homology and cross reactivity. A total of 18 blood samples from T1DM and controls were evaluated for the presence of MAP.ResultsPeptide BLAST analysis revealed a 44% overall identity between MAP Hsp65 and GAD65 with 75% positives in a 16 amino acid region. PyMOL 3D-structural analyses identified the same 16 amino acid region as a potential epitope for antibody binding. Preliminary data suggests a cross reactivity between MAP Hsp65, and a healthy rat pancreatic tissue homogenate against plasma from T1DM patients and rabbit polyclonal anti-MAP IgG. Long-term culture of human blood resulted MAP detection in 3/10 T1DM and 4/8 controls whereas MAP IgG was detected in 5/10 T1DM samples and 3/8 non-diabetic controls.ConclusionThe high degree of homology between GAD65 and MAP Hsp65 in an antigenic peptide region supports a possible mycobacterial role in triggering autoimmune destruction of pancreatic cells in T1DM. Reactivity of T1DM patient sera with MAP Hsp65 supports this finding. Culture of MAP from the blood of T1DM patients is intriguing. Overall, the preliminary data are mixed and do not exclude a possible role for MAP in T1DM pathogenesis. A larger study including well-characterized controls is needed to investigate the intriguing question of whether MAP is associated with T1DM or not?

Role of S100A8/A9 in the cross-talk between cancer cells and stroma-associated cells

s / Pancreatology 12 (2012) 502–597 589 1 Tampere Pancreas Laboratory, Tampere University Hospital, Tampere, Finland Department of Gastroenterology and Alimentary Tract Surgery, Tampere University Hospital, Tampere, Finland Department of Gastroenterological Surgery, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan Objectives: Studies with PANC-1 imply that autophagymay be induced in pancreatic ductal adenocarcinoma (PDA). Investigating the role of autophagy in patients is challenging as the induction of autophagy in pancreatic tissue may be affected by cell death mechanisms taking place after the tissue specimens have been harvested. Eliminating this postharvesting distraction would be crucial when investigating this phenomenon. No such study about autophagy in PDA in patients exists. Our aim was to study, whether autophagy is 1) induced in PDA compared to healthy pancreatic tissue in patients, and 2) correspondent to the autophagic status of PANC-1 cells in vitro. Patients and methods: Pancreatic samples were retrieved in laparotomy from patients undergoing pancreato-duodenectomy. Core-needle biopsies from the center of histologically-confirmed PDA tumors and from healthy pancreas (within the area to be resected) were immediately snapfrozen and proteins were extracted by repeated freeze-thaw cycles. The degree of autophagy was analysed by Western blotting of LC3-II, and compared to the degree of autophagy in PANC-1 cells (in basal conditions and when treated with anticancer drugs (gemcitabine and 5-FU) +/autophagy inhibitor chloroquine). Results: Autophagy was significantly induced in PDA compared to healthy pancreatic tissue in patients. This resembled the autophagic status of PANC-1 cells under basal culture conditions. Conclusions: Autophagy is induced in PDA in patients similarly to PANC-1 cells. In PANC-1 cells chloroquine increases the cytotoxicity of 5FU and gemcitabine by inhibiting autophagy. Thus patients with PDA may benefit from therapy where anticancer drugs are combined with an autophagy inhibitor.

Dual-energy perfusion-CT of pancreatic adenocarcinoma

PurposeTo evaluate the feasibility of dual-energy CT (DECT)-perfusion of pancreatic carcinomas for assessing the differences in perfusion, permeability and blood volume of healthy pancreatic tissue and histopathologically confirmed solid pancreatic carcinoma. Materials and methods24 patients with histologically proven pancreatic carcinoma were examined prospectively with a 64-slice dual source CT using a dynamic sequence of 34 dual-energy (DE) acquisitions every 1.5s (80ml of iodinated contrast material, 370mg/ml, flow rate 5ml/s). 80kVp, 140kVp, and weighted average (linearly blended M0.3) 120kVp-equivalent dual-energy perfusion image data sets were evaluated with a body-perfusion CT tool (Body-PCT, Siemens Medical Solutions, Erlangen, Germany) for estimating perfusion, permeability, and blood volume values. Color-coded parameter maps were generated. ResultsIn all 24 patients dual-energy CT-perfusion was. All carcinomas could be identified in the color-coded perfusion maps. Calculated perfusion, permeability and blood volume values were significantly lower in pancreatic carcinomas compared to healthy pancreatic tissue. Weighted average 120kVp-equivalent perfusion-, permeability- and blood volume-values determined from DE image data were 0.27±0.04min−1 vs. 0.91±0.04min−1 (p<0.0001), 0.5±0.07 *0.5min−1 vs. 0.67±0.05 *0.5min−1 (p=0.06) and 0.49±0.07min−1 vs. 1.28±0.11min−1 (p<0.0001). Compared with 80 and 140kVp the standard deviations of the kVp120kVp-equivalent values were manifestly smaller. ConclusionDual-energy CT-perfusion of the pancreas is feasible. The use of DECT improves the accuracy of CT-perfusion of the pancreas by fully exploiting the advantages of enhanced iodine contrast at 80kVp in combination with the noise reduction at 140kVp. Therefore using dual-energy perfusion data could improve the delineation of pancreatic carcinomas.

Adrenomedullin is Up-regulated in Patients With Pancreatic Cancer and Causes Insulin Resistance in β Cells and Mice

New-onset diabetes in patients with pancreatic cancer is likely to be a paraneoplastic phenomenon caused by tumor-secreted products. We aimed to identify the diabetogenic secretory product(s) of pancreatic cancer. Using microarray analysis, we identified adrenomedullin as a potential mediator of diabetes in patients with pancreatic cancer. Adrenomedullin was up-regulated in pancreatic cancer cell lines, in which supernatants reduced insulin signaling in beta cell lines. We performed quantitative reverse-transcriptase polymerase chain reaction and immunohistochemistry on human pancreatic cancer and healthy pancreatic tissues (controls) to determine expression of adrenomedullin messenger RNA and protein, respectively. We studied the effects of adrenomedullin on insulin secretion by beta cell lines and whole islets from mice and on glucose tolerance in pancreatic xenografts in mice. We measured plasma levels of adrenomedullin in patients with pancreatic cancer, patients with type 2 diabetes mellitus, and individuals with normal fasting glucose levels (controls). Levels of adrenomedullin messenger RNA and protein were increased in human pancreatic cancer samples compared with controls. Adrenomedullin and conditioned media from pancreatic cell lines inhibited glucose-stimulated insulin secretion from beta cell lines and islets isolated from mice; the effects of conditioned media from pancreatic cancer cells were reduced by small hairpin RNA-mediated knockdown of adrenomedullin. Conversely, overexpression of adrenomedullin in mice with pancreatic cancer led to glucose intolerance. Mean plasma levels of adrenomedullin (femtomoles per liter) were higher in patients with pancreatic cancer compared with patients with diabetes or controls. Levels of adrenomedullin were higher in patients with pancreatic cancer who developed diabetes compared those who did not. Adrenomedullin is up-regulated in patients with pancreatic cancer and causes insulin resistance in β cells and mice.

Non-invasive Monitoring of Pancreatic Tumor Progression in the RIP1-Tag2 Mouse by Magnetic Resonance Imaging

Assessing information on tumor progression in the RIP1-Tag2 mouse in vivo is a great challenge because the tumors form spontaneously throughout the pancreas and are difficult to detect with current imaging modalities. In this study, we focused on non-invasive magnetic resonance imaging, providing information on tumor growth. Tissue relaxation times were measured over time and were compared between tumors and healthy pancreatic tissue. The effects of age and body temperature on these relaxation times, possibly influencing image contrast and therefore detection capabilities, were evaluated. Tumors appeared hyperintense in T2-weighted images when they exceeded 0.8 mm in diameter, and both relaxation times showed significantly higher values in tumors than in the healthy pancreas. Visualization and monitoring of these small tumors in vivo is feasible, even under adverse conditions of permanent gut movement. In the mouse model studied, the relaxation times of tumors differed significantly from healthy pancreatic tissue.

Diffusion-weighted MR imaging; the importance of ADC and perfusion values in the differential diagnosis of pancreatic adenocarcinoma and mass forming pancreatitis

Despite the increasing diagnostic accuracy of cross sectional imaging modalities, the correct differentiation between pancreatic adenocarcinoma and mass forming pancreatitis has remained a challenge. Based on their 2 and ½ -year experience, the aim of the authors was to assess the clinical utility of diffusion-weighted magnetic resonance imaging in the diagnosis and discernment of pancreatic adenocarcinoma and mass forming pancreatitis. 3 b-values diffusion-weighted magnetic resonance examinations were performed in 19 patients suffering from adenocarcinoma and in 8 patients with pancreatitis. 12 healthy patients were examined as reference. Apparent diffusion coefficient and perfusion values were calculated. Malignancy was verified by pathology in all cases. An inflammatory disease was diagnosed on the basis of previous medical history, changes in laboratory values, follow-up computer tomographic examinations and improvement in the patients' condition. Comparison of the apparent diffusion coefficient and perfusion values revealed significant differences between healthy pancreatic tissues and those affected by inflammation or tumor. The highest apparent diffusion coefficient and perfusion values were detected in the normal pancreas. Mass forming pancreatitis had diminished the apparent diffusion coefficient and perfusion values, whereas these values were the lowest in tumorous tissues. In agreement with literature data, the authors conclude that diffusion-weighted magnetic resonance imaging is a promising differential-diagnostic imaging tool in the distinction of circumscribed pancreatic lesions.

S100P-Binding Protein, S100PBP, Mediates Adhesion through Regulation of Cathepsin Z in Pancreatic Cancer Cells

Several S100 proteins are up-regulated in pancreatic ductal adenocarcinoma (PDAC), the most significant being S100P. We previously reported on S100PBP, a binding partner of S100P, that shows no homology to any described protein and whose functions are completely unknown. To determine S100PBP expression across human tissues and organs, immunohistochemistry was performed using both multiorgan- and in-house-constructed pancreatic tissue microarrays. To establish S100PBP functions, cell lines with either stably overexpressed or silenced S100PBP were generated and investigated using Affymetrix gene expression arrays and complementary functional assays. We show that S100PBP is differentially expressed in various healthy and tumor specimens, which is both cancer- and tissue-type dependent. In healthy pancreas, S100PBP is expressed in the nuclear/perinuclear region of both exocrine and endocrine compartments. In early precancerous lesions, S100PBP is translocated to the cytoplasm, whereas in PDAC and metastatic lesions, its expression is significantly diminished. The most pronounced phenotypic change after manipulation of S100PBP expression was seen in adhesion; this was significantly reduced after S100PBP up-regulation and increased after S100PBP silencing. Up-regulation or silencing of S100PBP also led to a concomitant change in the levels of the protease cathepsin Z, the silencing of which significantly reduced PDAC cell adhesion. We further demonstrate that the interaction of cathepsin Z with arginine-glycine-aspartic acid-binding integrins, specifically αvβ5, mediates the changes seen in adhesion of PDAC cells.

Computed Tomography Perfusion Analysis of Pancreatic Carcinoma

The purpose of this study was to evaluate CT perfusion of pancreatic carcinomas using the Patlak model for assessing perfusion, permeability, and blood volume. A total of 25 patients with pancreatic carcinoma were examined prospectively with a 64-slice computed tomography (CT) using a dynamic sequence after intravenous injection of 80-mL contrast material (370 mg/mL; flow rate, 5 mL/s). Eighty-kilovolt (peak) perfusion acquisitions were evaluated for estimating perfusion parameters for carcinoma and healthy tissue using a 2-compartment model (Patlak model). Twenty patients had hypodense tumors; in 5 patients, the tumor could not be delineated in contrast-enhanced CT. All carcinomas could be identified clearly in the color-coded perfusion maps. Perfusion, permeability, and blood volume values were significant lower in pancreatic carcinomas compared to healthy pancreatic tissue (0.27 ± 0.20 vs 0.89 ± 0.19 min, P < 0.0001; 0.43 ± 0.20 vs 0.75 ± 0.16 × 0.5 min, P < 0.0001; and 38.9 ± 20.7 vs 117.8 ± 46.9 mL/100 mL, P < 0.0001). Computed tomographic perfusion of the pancreas using a 2-compartment perfusion model is feasible. Color-coded perfusion maps could be a helpful tool to delineate pancreatic carcinomas even if they are not visible in contrast-enhanced CT.

Expression and therapeutic relevance of heat-shock protein 90 in pancreatic endocrine tumors

Pancreatic endocrine tumors (PET) represent a heterogenous group of neoplasms. Although surgical resection is considered a safe and effective treatment for many PET, therapeutic options for inoperable and progressive PET are limited. The expression of heat-shock protein (HSP) 90 was investigated in 120 clinically and pathomorphologically well-characterized PET from 84 patients using immunohistochemistry. In addition, in 19 snap-frozen PET and in three healthy pancreatic tissues, we performed immunoblot analyses, and in 15 snap-frozen PET and in three healthy pancreatic tissues, we investigated the expression of HSP90 isoforms by means of semiquantitative RT-PCR. Functional tests were conducted using the human pancreas carcinoid cell line BON and the mouse insulinoma cell line β-TC-3. HSP90 was expressed in 95% of the PET patients. The transcript levels of the HSP90 isoforms HSP90α, HSP90β, glucose-related protein 94, and TNF receptor-associated protein 1 were significantly increased in PET compared with non-neoplastic pancreatic tissues. The treatment of the cell lines BON and β-TC-3 with the HSP90 inhibitors 17-allylamino-17-demethoxygeldanamycin and 17-dimethylaminoethylamino-17-demethoxy-geldanamycin resulted in significant, dose-dependent reduction of cell viability, cell cycle arrest, and increased apoptosis. Furthermore, HSP90 inhibition induced the degradation and inactivation of several oncogenetic HSP90 client proteins in a time- and dose-dependent manner. HSP90 inhibitors increased the therapeutic effects of doxorubicin and 5-fluorucacil in BON and β-TC-3 cells. HSP90 is expressed in the vast majority of PET and its inhibition reveals significant treatment effects in vitro. Thus, HSP90 qualifies as a promising new target.

Assessment of Tumor Vascularization in Pancreatic Adenocarcinoma Using 128-Slice Perfusion Computed Tomography Imaging

Computed tomography (CT) perfusion studies can provide valuable information regarding tumor vascularization. We report on a study assessing CT perfusion characteristics in the normal pancreas and in patients with pancreatic adenocarcinoma. Twenty healthy subjects and 20 patients with histologically confirmed pancreatic adenocarcinoma were included in the study after written informed consent and approval by our institutional review board. All subjects underwent perfusion CT imaging of the pancreas using 128-slice dual-source CT. The scanning sequence included 18 scans. Parametric maps of blood volume (BV), blood flow (BF), and permeability surface area product (PS) were generated and compared with density measurements. In normal pancreas, no significant difference in perfusion values was observed between head, body, and tail of the pancreas. Mean organ values were 76.76 (SD, 15.6) mL/100 g/min, 15.80 (SD, 2.40) mL/100 g, and 27.74 (SD, 16.8) mL/100 g/min for BF, BV, and PS, respectively. Compared with the normal pancreas, a 60% reduction in BF and BV was observed in the tumor tissue. Perfusion values gradually increased toward the tumor rim. Necrotic tumor areas were identified in 25% of patients. No significant differences were observed when comparing normal pancreas and healthy pancreatic tissue in adenocarcinoma patients. The feasibility of whole-tumor perfusion imaging using 128-slice CT was demonstrated in patients with pancreatic adenocarcinoma. Perfusion CT provides additional information compared with image assessment based on density measurements (Hounsfield units) and allows noninvasive assessment of vascularization in the tumor tissue.