Simultaneous gene silencing of Bcl-2, XIAP and Survivin re-sensitizes pancreatic cancer cells towards apoptosis

Abstract Background Pancreatic ductal adenocarcinoma shows a distinct apoptosis resistance, which contributes significantly to the aggressive nature of this tumor and constrains the effectiveness of new therapeutic strategies. Apoptosis resistance is determined by the net balance of the cells pro-and anti-apoptotic "control mechanisms". Numerous dysregulated anti-apoptotic genes have been identified in pancreatic cancer and seem to contribute to the high anti-apoptotic buffering capacity. We aimed to compare the benefit of simultaneous gene silencing (SGS) of several candidate genes with conventional gene silencing of single genes. Methods From literature search we identified the anti-apoptotic genes XIAP, Survivin and Bcl-2 as commonly upregulated in pancreatic cancer. We performed SGS and silencing of single candidate genes using siRNA molecules in two pancreatic cancer cell lines. Effectiveness of SGS was assessed by qRT-PCR and western blotting. Apoptosis induction was measured by flow cytometry and caspase activation. Results Simultaneous gene silencing reduced expression of the three target genes effectively. Compared to silencing of a single target or control, SGS of these genes resulted in a significant higher induction of apoptosis in pancreatic cancer cells. Conclusions In the present study we performed a subliminal silencing of different anti-apoptotic target genes simultaneously. Compared to silencing of single target genes, SGS had a significant higher impact on apoptosis induction in pancreatic cancer cells. Thereby, we give further evidence for the concept of an anti-apoptotic buffering capacity of pancreatic cancer cells.</p

The impact of surgical experience and frequency of practice on perioperative outcomes in pancreatic surgery

Objective We aimed to determine the impact of surgical experience and frequency of practice on perioperative morbidity and mortality in pancreatic surgery. Methods 1281 patients that underwent pancreatic resections from 1993 to 2013 were retrospectively analyzed using logistic regression models. All cases were stratified according to the surgeon’s level of experience, which was based on the number of previously performed pancreatic resections and the extent of received supervision (novice: n  90 / none). Additional stratification was based on the frequency of practice (sporadic: 3 resections > 6 weeks, frequent: 3 resections ≤6 weeks). Results The novice and experienced categories were related to a decreased risk of postoperative pancreatic fistulas (odds ratio [OR] 0.46, 95% confidence interval [CI] 0.26–0.82 and 0.54, 95% CI 0.36–0.82) and in-hospital mortality (OR 0.45, 95% CI 0.17–1.16 and 0.42, 95% CI 0.21–0.83) compared to the intermediate category. Frequent practice was associated with a significantly lower risk of delayed gastric emptying (OR 0.56, 95% CI 0.38–0.83), postpancreatectomy hemorrhage (OR 0.64, 95% CI 0.42–0.98) and in-hospital mortality (OR 0.45, 95% CI 0.24–0.87). Conclusions Our results emphasize the importance of supervision within a pancreatic surgery training program. In addition, our data underline the need of a sufficient patient caseload to ensure frequent practice

Gene expression analysis of pancreatic cell lines reveals genes overexpressed in pancreatic cancer

Background: Pancreatic cancer is one of the leading causes of cancer-related death. Using DNA gene expression analysis based on a custom made Affymetrix cancer array, we investigated the expression pattern of both primary and established pancreatic carcinoma cell lines. Methods: We analyzed the gene expression of 5 established pancreatic cancer cell lines (AsPC-1, BxPC-3, Capan-1, Capan-2 and HPAF II) and 5 primary isolates, 1 of them derived from benign pancreatic duct cells. Results: Out of 1,540 genes which were expressed in at least 3 experiments, we found 122 genes upregulated and 18 downregulated in tumor cell lines compared to benign cells with a fold change > 3. Several of the upregulated genes (like Prefoldin 5, ADAM9 and E-cadherin) have been associated with pancreatic cancer before. The other differentially regulated genes, however, play a so far unknown role in the course of human pancreatic carcinoma. By means of immunohistochemistry we could show that thymosin [β-10 (TMSB10), upregulated in tumor cell lines, is expressed in human pancreatic carcinoma, but not in non-neoplastic pancreatic tissue, suggesting a role for TMSB10 in the carcinogenesis of pancreatic carcinoma. Conclusion: Using gene expression profiling of pancreatic cell lines we were able to identify genes differentially expressed in pancreatic adenocarcinoma, which might contribute to pancreatic cancer development.Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich

Evaluation of response using FDG-PET/CT and diffusion weighted MRI after radiochemotherapy of pancreatic cancer: a non-randomized, monocentric phase II clinical trial—PaCa-DD-041 (Eudra-CT 2009-011968-11)

Abstract Background Pancreatic cancer is a devastating disease with a 5-year survival rate of 20–25%. As approximately only 20% of patients diagnosed with pancreatic cancer are initially staged as resectable, it is necessary to evaluate new therapeutic approaches. Hence, neoadjuvant (radio)chemotherapy is a promising therapeutic option, especially in patients with a borderline resectable tumor. The aim of this non-randomized, monocentric, prospective, phase II clinical study was to assess the prognostic value of functional imaging techniques, i.e., [18F]2-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (FDG-PET/CT) and diffusion weighted magnetic resonance imaging (DW-MRI), prior to and during neoadjuvant radiochemotherapy. Methods Patients with histologically proven resectable, borderline resectable or unresectable non-metastatic pancreatic adenocarcinoma received induction chemotherapy followed by neoadjuvant radiochemotherapy. Patients underwent FDG-PET/CT and DW-MRI including T1- and T2-weighted sequences prior to and after neoadjuvant chemotherapy as well as following induction radiochemotherapy. The primary endpoint was the evaluation of the response as quantified by the standardized uptake value (SUV) measured with FDG-PET. Response to treatment was evaluated by FDG-PET and DW-MRI during and after the neoadjuvant course. Morphologic staging was performed using contrast-enhanced CT and contrast-enhanced MRI to decide inclusion of patients and resectability after neoadjuvant therapy. In those patients undergoing subsequent surgery, imaging findings were correlated with those of the pathologic resection specimen. Results A total of 25 patients were enrolled in the study. The response rate measured by FDG-PET was 85% with a statistically significant decrease of the maximal SUV (SUVmax) during therapy (p < 0.001). Using the mean apparent diffusion coefficient (ADC), response was not detectable with DW-MRI. After neoadjuvant treatment 16 patients underwent surgery. In 12 (48%) patients tumor resection could be performed. The median overall survival of all patients was 25 months (range: 7–38 months). Conclusion Based on these limited patient numbers, it was possible to show that this trial design is feasible and that the neoadjuvant therapy regime was well tolerated. FDG-PET/CT may be a reliable method to evaluate response to the combined therapy. In contrast, when evaluating the response using mean ADC, DW-MRI did not show conclusive results

Chronic pancreatitis of the pancreatic remnant is an independent risk factor for pancreatic fistula after distal pancreatectomy

Background: There is an ongoing debate about the best closure technique after distal pancreatectomy (DP). The aim of the closure is to prevent the formation of a clinically relevant post-operative pancreatic fistula (POPF). Stapler technique seems to be equal compared with hand-sewn closure of the remnant. For both techniques, a fistula rate of approximately 30% has been reported. Methods: We retrospectively analyzed our DPs between 01/2000 and 12/2010. In all cases, the pancreatic duct was over sewn with a separately stitched ligation of the pancreatic duct (5*0 PDS) followed by a single-stitched hand-sewn closure of the residual pancreatic gland. The POPF was classified according to the criteria of the International Study Group for Pancreatic Fistula (ISGPF). Univariate and multivariate analyses of potential risk factors for the formation of POPF were performed. Indications for operations included cystic tumors (n = 53), neuroendocrine tumors (n = 27), adenocarcinoma (n = 22), chronic pancreatitis (n = 9), metastasis (n = 6), and others (n = 7). Results: During the period, we performed 124 DPs (♀ = 74, ♂ = 50). The mean age was 57.5 years (18–82). The POPF rates according to the ISGPF criteria were: no fistula, 54.8% (n = 68); grade A, 24.2% (n = 30); grade B, 19.3% (n = 24); and grade C, 1.7% (n = 2). Therefore, in 21.0% (n = 26) of the cases, a clinically relevant pancreatic fistula occurred. The mean postoperative stay was significantly higher after grade B/C fistula (26.3 days) compared with no fistula/grade A fistula (13.7 days) (p < 0.05). The uni- and multivariate analyses showed chronic pancreatitis of the pancreatic remnant to be an independent risk factor for the development of POPF (p = 0.004 OR 7.09). Conclusion: By using a standardized hand-sewn closure technique of the pancreatic remnant after DP with separately stitched ligation of the pancreatic duct, a comparably low fistula rate can be achieved. Signs of chronic pancreatitis of the pancreatic remnant may represent a risk factor for the development of a pancreatic fistula after DP and therefore an anastomosis of the remnant to the intestine should be considered

Проект узла гидрирования сернистых соединений

Конструирование аппарата для гидрирования сернистых соединений содержащихся в природном газе, а также исследование методов очистки природного газа.Designing an apparatus for hydrogenating sulfur compounds in natural gas, and studying methods for purifying natural gas

Examination of Apoptosis Signaling in Pancreatic Cancer by Computational Signal Transduction Analysis

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) remains an important cause of cancer death. Changes in apoptosis signaling in pancreatic cancer result in chemotherapy resistance and aggressive growth and metastasizing. The aim of this study was to characterize the apoptosis pathway in pancreatic cancer computationally by evaluation of experimental data from high-throughput technologies and public data bases. Therefore, gene expression analysis of microdissected pancreatic tumor tissue was implemented in a model of the apoptosis pathway obtained by computational protein interaction prediction. METHODOLOGY/PRINCIPAL FINDINGS: Apoptosis pathway related genes were assembled from electronic databases. To assess expression of these genes we constructed a virtual subarray from a whole genome analysis from microdissected native tumor tissue. To obtain a model of the apoptosis pathway, interactions of members of the apoptosis pathway were analysed using public databases and computational prediction of protein interactions. Gene expression data were implemented in the apoptosis pathway model. 19 genes were found differentially expressed and 12 genes had an already known pathophysiological role in PDAC, such as Survivin/BIRC5, BNIP3 and TNF-R1. Furthermore we validated differential expression of IL1R2 and Livin/BIRC7 by RT-PCR and immunohistochemistry. Implementation of the gene expression data in the apoptosis pathway map suggested two higher level defects of the pathway at the level of cell death receptors and within the intrinsic signaling cascade consistent with references on apoptosis in PDAC. Protein interaction prediction further showed possible new interactions between the single pathway members, which demonstrate the complexity of the apoptosis pathway. CONCLUSIONS/SIGNIFICANCE: Our data shows that by computational evaluation of public accessible data an acceptable virtual image of the apoptosis pathway might be given. By this approach we could identify two higher level defects of the apoptosis pathway in PDAC. We could further for the first time identify IL1R2 as possible candidate gene in PDAC

Google Goes Cancer: Improving Outcome Prediction for Cancer Patients by Network-Based Ranking of Marker Genes

Predicting the clinical outcome of cancer patients based on the expression of marker genes in their tumors has received increasing interest in the past decade. Accurate predictors of outcome and response to therapy could be used to personalize and thereby improve therapy. However, state of the art methods used so far often found marker genes with limited prediction accuracy, limited reproducibility, and unclear biological relevance. To address this problem, we developed a novel computational approach to identify genes prognostic for outcome that couples gene expression measurements from primary tumor samples with a network of known relationships between the genes. Our approach ranks genes according to their prognostic relevance using both expression and network information in a manner similar to Google's PageRank. We applied this method to gene expression profiles which we obtained from 30 patients with pancreatic cancer, and identified seven candidate marker genes prognostic for outcome. Compared to genes found with state of the art methods, such as Pearson correlation of gene expression with survival time, we improve the prediction accuracy by up to 7%. Accuracies were assessed using support vector machine classifiers and Monte Carlo cross-validation. We then validated the prognostic value of our seven candidate markers using immunohistochemistry on an independent set of 412 pancreatic cancer samples. Notably, signatures derived from our candidate markers were independently predictive of outcome and superior to established clinical prognostic factors such as grade, tumor size, and nodal status. As the amount of genomic data of individual tumors grows rapidly, our algorithm meets the need for powerful computational approaches that are key to exploit these data for personalized cancer therapies in clinical practice

Endoskopie zwischen Chirurgie und Gastroenterologie – aus der Sicht der Chirurgischen Arbeitsgemeinschaft für Endoskopie und Sonographie (CAES)

Die Endoskopie ist ein wesentlicher Bestandteil der Chirurgie. Nicht nur die Diagnostik, sondern speziell die operative Endoskopie bedarf der besonderen Kompetenz von Chirurgen. Dies wurde in der Vergangenheit in einigen Zentren eindeutig belegt. Zukünftig wird die chirurgische Endoskopie in ihrer Wertigkeit steigen. Die konventionelle Chirurgie wird schon heute zum Teil durch minimal invasive Verfahren abgelöst. Die Progredienz dieser Entwicklung ist absehbar. Dazu werden auch Kombinationen der flexiblen Endoskopie mit laparoskopischen Techniken und der Sonographie zunehmend zum Einsatz kommen. Daneben wird die Kooperation mit den Gastroenterologen intensiviert. Ein kürzlich verabschiedetes Konsensuspapier der Deutschen Gesellschaft für Verdauungsund Stoffwechselkrankheiten und der Deutschen Gesellschaft für Viszeralchirurgie unterstreicht den bilateralen Wunsch zur Zusammenarbeit. Ziele bestehen in der Optimierung der endoskopischen Leistungen. Patientenversorgung, Forschung und Lehre können so synergistisch weiter verbessert werden. Die Voraussetzung zur Durchsetzung dieser Ziele ist die gegenseitige Anerkennung der Kompetenz, die Unterstützung bei der Novellierung der Weiterbildungsordnung und die dem Bedarf und den Fortschritten angepasste Weiterentwicklung des Papiers. Daneben werden Chirurgen und Gastroenterologen die fachspezifischen Fragestellungen der intraluminalen Endoskopie auch weiterhin selbständig verfolgen.Endoscopy between Surgery and Gastroenterology – the Point of View of the Chirurgische Arbeitsgemeinschaft für Endoskopie und Sonographie (CAES) Flexible endoscopy is an important part of surgery. Not only diagnostic investigation, but especially operative endoscopy needs surgical competence. This has been proven in several centers. In the future the status of surgical endoscopy will increase. Already today, conventional surgery has been replaced more and more by minimal invasive procedures. This evolution probably will continue. The combination of flexible endoscopy with laparoscopy and sonography will be routinely introduced into daily surgical work. At the same time cooperation with medical gastroenterologists is intensified. A recently realized agreement of the German Society for Digestive and Metabolic Diseases and the German Society for Visceral Surgery confirms the efforts to work together in this field. The goal is to optimize endoscopic performance. Patient\'\'s care, research, and teaching can be synergistically improved. Conditions for successful consensual work are the acceptance of each others competence, the support of activities for actual education programs and the development of the agreement, depending on further necessities and progress. Besides that, specifically related research in intraluminal endoscopy will be continued by surgeons and medical gastroenterologists.Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich