J.-Matthias Löhr

The M-ANNHEIM classification of chronic pancreatitis : introduction of a unifying classification system based on a review of previous classifications of the disease

BackgroundSeveral classification systems of chronic pancreatitis have been proposed to provide a basis for treatment and research. All of these previous classifications were designed at the height of pancreatic research of their respective times; thus, each represented the most current knowledge available to pancreatologists at the time. However, none of these classifications provide simultaneously a simple standardized system for the clinical classification of chronic pancreatitis according to etiology, clinical stage, and severity of the disease, nor are they consistently useful for directing clinical practice and comparing interinstitutional data. Thus, we aimed to develop a new classification system of chronic pancreatitis to provide a framework for studying the interaction of various risk factors on the course of the disease.MethodsWe reviewed the literature on the clinical course of all different forms of chronic pancreatitis, and we reviewed all previous classification systems of the disease. This approach provided a basis for the development of a new and unifying classification of chronic pancreatitis.ResultsWe established the M-ANNHEIM multiple risk factor classification system based on the current knowledge of acute and chronic pancreatitis. This classification allows patients to be categorized according to the etiology, clinical stage, and severity of their disease. The severity of pancreatic inflammation was assessed using a scoring system that takes into account the clinical symptoms and treatment options of chronic pancreatitis. Finally, four hypothetical patients were categorized according to the M-ANNHEIM classification system to provide examples of its applicability in clinical practice.ConclusionsThe M-ANNHEIM multiple risk factor classification system is simple, objective, accurate, and relatively noninvasive, and it incorporates etiology, different stages of the disease, and various degrees of clinical severity. This new classification system will be helpful for investigating the impact and interaction of various risk factors on the course of the disease and will facilitate the comparison and combination of interinstitutional data.

Pancreatic cancer microenvironment

Pancreatic ductal adenocarcinoma remains an extremely aggressive malignancy that is virtually therapy‐resistant and has therefore one of the worst prognoses of all human cancers. The focus of research, which had been placed mostly on genetic and epigenetic alterations of the cancer cells themselves, has shifted gradually towards the microenvironment. The cancer microenvironment consists of various components, including fibroblasts, endothelial cells, immune cells, and endocrine cells, that interact with each other and the cancer cells in a complex fashion. This interplay has implications for pancreatic cancer cell growth, migration and invasion, angiogenesis, and immunological recognition of cancer cells. Evidence is accumulating that the cancer microenvironment plays an active role in disease progression, and efforts are being made to target this interplay between cancer cells and host cells to improve the outcome of this deadly disease.

Addressing the challenges of pancreatic cancer: future directions for improving outcomes

Pancreatic ductal adenocarcinoma (PDAC), which accounts for more than 90% of all pancreatic tumours, is a devastating malignancy with an extremely poor prognosis, as shown by a 1-year survival rate of around 18% for all stages of the disease. The low survival rates associated with PDAC primarily reflect the fact that tumours progress rapidly with few specific symptoms and are thus at an advanced stage at diagnosis in most patients. As a result, there is an urgent need to develop accurate markers of pre-invasive pancreatic neoplasms in order to facilitate prediction of cancer risk and to help diagnose the disease at an earlier stage. However, screening for early diagnosis of prostate cancer remains challenging and identifying a highly accurate, low-cost screening test for early PDAC for use in clinical practice remains an important unmet need. More effective therapies are also crucial in PDAC, since progress in identifying novel therapies has been hampered by the genetic complexity of the disease and treatment remains a major challenge. Presently, the greatest step towards improved treatment efficacy has been made in the field of palliative chemotherapy by introducing FOLFIRINOX (folinic acid, 5-fluorouracil, irinotecan and oxaliplatin) and gemcitabine/nab-paclitaxel. Strategies designed to raise the profile of PDAC in research and clinical practice are a further requirement in order to ensure the best treatment for patients. This article proposes a number of approaches that may help to accelerate progress in treating patients with PDAC, which, in turn, may be expected to improve the quality of life and survival for those suffering from this devastating disease.

Autoantibodies against the exocrine pancreas in autoimmune pancreatitis: gene and protein expression profiling and immunoassays identify pancreatic enzymes as a major target of the inflammatory process

OBJECTIVES:Autoimmune pancreatitis (AIP) is thought to be an immune-mediated inflammatory process, directed against the epithelial components of the pancreas. The objective was to identify novel markers of disease and to unravel the pathogenesis of AIP.METHODS:To explore key targets of the inflammatory process, we analyzed the expression of proteins at the RNA and protein level using genomics and proteomics, immunohistochemistry, western blot, and immunoassay. An animal model of AIP with LP-BM5 murine leukemia virus-infected mice was studied in parallel. RNA microarrays of pancreatic tissue from 12 patients with AIP were compared with those of 8 patients with non-AIP chronic pancreatitis.RESULTS:Expression profiling showed 272 upregulated genes, including those encoding for immunoglobulins, chemokines and their receptors, and 86 downregulated genes, including those for pancreatic proteases such as three trypsinogen isoforms. Protein profiling showed that the expression of trypsinogens and other pancreatic enzymes was greatly reduced. Immunohistochemistry showed a near-loss of trypsin-positive acinar cells, which was also confirmed by western blotting. The serum of AIP patients contained high titers of autoantibodies against the trypsinogens PRSS1 and PRSS2 but not against PRSS3. In addition, there were autoantibodies against the trypsin inhibitor PSTI (the product of the SPINK1 gene). In the pancreas of AIP animals, we found similar protein patterns and a reduction in trypsinogen.CONCLUSIONS:These data indicate that the immune-mediated process characterizing AIP involves pancreatic acinar cells and their secretory enzymes such as trypsin isoforms. Demonstration of trypsinogen autoantibodies may be helpful for the diagnosis of AIP.

ATP-Binding Cassette C Transporters in Human Pancreatic Carcinoma Cell Lines

Background: Pancreatic cancer is characterized by high resistance to chemotherapy. Such chemoresistance can be mediated by multidrug resistance proteins (MRPs), breast cancer resistance protein (BCRP), and MDR1 P-glycoprotein. However, the contribution of individual MRP isoforms to chemoresistance in pancreatic carcinoma is unclear. We studied ATP-binding cassette (ABC) transporter expression in human pancreatic carcinoma cell lines as compared to primary pancreatic duct cells, and analyzed the MRP expression profile in 5-fluorouracil-resistant cells. Methods: Transporter expression was analyzed by quantitative and qualitative RT-PCR, by immunoblot, and chemoresistance by cytotoxicity assay. Results: Primary pancreatic duct cells expressed MRP1, MRP3, MRP4, and MRP5, but not MRP2 mRNA. The established carcinoma cell lines expressed MRP1, MRP4, and MRP5, most of them also MRP2, MRP3, MRP7, and BCRP, but none contained detectable amounts of MRP6, MRP8, or MRP9 mRNA. Immunoblot analyses demonstrated presence of MRP1, MRP4, and MRP5 protein in all, but MRP3 and BCRP protein only in some of these cells. Compared to parental Capan-1 cells, Capan-1 cells with acquired chemoresistance towards 5-fluorouracil showed an upregulated mRNA and protein expression of MRP3, MRP4, and MRP5. In addition, silencing of MRP5 by RNA interference resulted in enhanced sensitivity of parental Capan-1 cells towards 5-fluorouracil cytotoxicity. Conclusion: MRP3, MRP4, and MRP5 are upregulated in 5-fluorouracil-resistant cells, and MRP5 contributes to 5-FU resistance in pancreatic carcinoma cells.

Real-time assessment of tissue hypoxia in vivo with combined photoacoustics and high-frequency ultrasound.

Purpose: In preclinical cancer studies, non-invasive functional imaging has become an important tool to assess tumor development and therapeutic effects. Tumor hypoxia is closely associated with tumor aggressiveness and is therefore a key parameter to be monitored. Recently, photoacoustic (PA) imaging with inherently co-registered high-frequency ultrasound (US) has reached preclinical applicability, allowing parallel collection of anatomical and functional information. Dual-wavelength PA imaging can be used to quantify tissue oxygen saturation based on the absorbance spectrum differences between hemoglobin and deoxyhemoglobin. Experimental Design: A new bi-modal PA/US system for small animal imaging was employed to test feasibility and reliability of dual-wavelength PA for measuring relative tissue oxygenation. Murine models of pancreatic and colon cancer were imaged, and differences in tissue oxygenation were compared to immunohistochemistry for hypoxia in the corresponding tissue regions. Results: Functional studies proved feasibility and reliability of oxygenation detection in murine tissue in vivo. Tumor models exhibited different levels of hypoxia in localized regions, which positively correlated with immunohistochemical staining for hypoxia. Contrast-enhanced imaging yielded complementary information on tissue perfusion using the same system. Conclusion: Bimodal PA/US imaging can be utilized to reliably detect hypoxic tumor regions in murine tumor models, thus providing the possibility to collect anatomical and functional information on tumor growth and treatment response live in longitudinal preclinical studies.

EXPRESSION OF CANCER TESTIS ANTIGENS IN PANCREATIC CARCINOMA CELL LINES, PANCREATIC ADENOCARCINOMA AND CHRONIC PANCREATITIS

In order to define antigens that might be suitable as vaccines for pancreatic carcinoma, we investigated the composite expression of 10 cancer testis (CT) antigens (SCP‐1, NY‐ESO‐1, SSX‐1, SSX‐2, SSX‐4, GAGE, MAGE‐3, MAGE‐4, CT‐7 and CT‐8) by Reverse Transcriptase‐PCR (RT‐PCR) in fresh biopsies of human pancreatic adenocarcinoma, chronic pancreatitis and pancreatic carcinoma cell lines. While all CT genes were frequently expressed in cell lines derived from pancreatic cancer, no expression of MAGE‐3, SSX‐1, SSX‐2, NY‐ESO‐1 and CT‐7 was detected in fresh tumor biopsies, and MAGE‐4 (1/52), SSX‐4 (1/39) and CT‐8 (2/41) were only rarely expressed. In contrast, HOM‐TES‐14/SCP‐1 was expressed in 48% (29/61) and GAGE in 21% (13/61) of cases, respectively. One CT gene was expressed by 59% (75% in male, 46% in female patients; p = 0.05) and 2 or more CT genes by 15% of the samples. SCP‐1 protein expression correlated well with mRNA expression. While SCP‐1 and GAGE were absent in normal pancreas, they were found in 2/8 (SCP‐1) and 1/8 (GAGE) samples of chronic pancreatitis, respectively, supporting the concept of chronic pancreatitis as a premalignant condition. SCP‐1 and GAGE represent promising candidates for vaccine development in pancreatic carcinoma. Whether SCP‐1 and GAGE expression identify cases of chronic pancreatitis with a high risk of malignant transformation remains to be shown.

Desmoplasia and Chemoresistance in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) occurs mainly in people older than 50 years of age. Although great strides have been taken in treating PDAC over the past decades its incidence nearly equals its mortality rate and it was quoted as the 4th leading cause of cancer deaths in the U.S. in 2012. This review aims to focus on research models and scientific developments that help to explain the extraordinary resistance of PDAC towards current therapeutic regimens. Furthermore, it highlights the main features of drug resistance including mechanisms promoted by cancer cells or cancer stem cells (CSCs), as well as stromal cells, and the acellular components surrounding the tumor cells—known as peritumoral desmoplasia—that affects intra-tumoral drug delivery. Finally, therapeutic concepts and avenues for future research are suggested, based on the topics discussed.

Short-term Results of a Magnetic Resonance Imaging–Based Swedish Screening Program for Individuals at Risk for Pancreatic Cancer

IMPORTANCE Pancreatic cancer is the fourth leading cause of cancer-related death in Western countries. In approximately 10% of all patients with pancreatic cancer, it is possible to define a positive family history for pancreatic cancer or for one of the other related genetic syndromes. A screening program for individuals at risk is recommended; however, surveillance modalities have not been defined yet. OBJECTIVE To analyze the short-term results of a prospective clinical surveillance program for individuals at risk for pancreatic cancer using a noninvasive magnetic resonance imaging (MRI)-based screening protocol. DESIGN, SETTING AND PARTICIPANTS A prospective observational study of all patients with a genetic risk for developing pancreatic cancer who were referred to Karolinska University Hospital between January 1, 2010, and January 31, 2013, using an MRI-based surveillance program. All patients were investigated for the most common genetic mutations associated with pancreatic cancer. EXPOSURE A noninvasive MRI-based screening protocol. MAIN OUTCOMES AND MEASURES The ability of MRI to identify potential precancerous or early cancers in individuals at risk for pancreatic cancer. RESULTS Forty patients (24 women and 16 men) were enrolled. The mean age was 49.9 years. The mean length of follow-up was 12.9 months. The numbers of relatives affected by pancreatic cancer were 5 in 2 patients (5%), 4 in 5 patients (12.5%), 3 in 17 patients (42.5%), 2 in 14 patients (35%), and 1 in 2 patients (5%). In 4 patients (10%), a p16 mutation was found; in 3, a BRCA2 mutation (7.5%); and in 1, a BRCA1 mutation (2.5%). In 16 patients (40%), MRI revealed a pancreatic lesion: intraductal papillary mucinous neoplasia (14 patients, 35%) and pancreatic ductal adenocarcinoma (2 patients, 5%). One patient had a synchronous intraductal papillary mucinous neoplasia and pancreatic ductal adenocarcinoma. Five patients (12.5%) required surgery (3 for pancreatic ductal adenocarcinoma and 2 for intraductal papillary mucinous neoplasia), while the remaining 35 are under continued surveillance. CONCLUSIONS AND RELEVANCE During a median follow-up of approximately 1 year, pancreatic lesions were detected in 40% of the patients, of whom 5 underwent surgery. Although the study time was relatively short, the surveillance program in individuals at risk seems to be effective.

Transforming growth factor-beta induces nerve growth factor expression in pancreatic stellate cells by activation of the ALK-5 pathway.

Nerve growth factor (NGF), a survival factor for neurons enforces pain by sensitizing nociceptors. Also in the pancreas, NGF was associated with pain and it can stimulate the proliferation of pancreatic cancer cells. Hepatic stellate cells (HSC) respond to NGF with apoptosis. Transforming growth factor (TGF)-β, one of the strongest pro-fibrogenic activators of pancreatic stellate cells (PSC) induced NGF and its two receptors in an immortalized human cell line (ihPSC) and primary rat PSC (prPSC) as determined by RT-PCR, western blot, and immunofluorescence. In contrast to HSC, PSC expressed both NGF receptors, although p75NTR expression was weak in prPSC. In contrast to ihPSC TGF-β activated both Smad signaling cascades in prPSC. NGF secretion was diminished by the activin-like kinase (ALK)-5 inhibitor SB431542, indicating the predominant role of ALK5 in activating the NGF system in PSC. While NGF did not affect proliferation or survival of PSC it induced expression of Inhibitor of Differentiation-1. We conclude that under conditions of upregulated TGF-β, like fibrosis, NGF levels will also increase in PSC which might contribute to pancreatic wound healing responses.