Inherited pancreatic cancer: improvements in our understanding of genetics and screening

Inherited pancreatic cancers represent approximately 5-10% of all pancreatic cancers. Pancreatic cancer may be inherited as part of a known cancer syndrome or in association with hereditary pancreatitis or cystic fibrosis. However, most inherited pancreatic cancers do not occur in the context of a known syndrome, and these are referred to as familial pancreatic cancers. Growing evidence suggests the presence of a single autosomal dominant gene in familial pancreatic cancer kindreds, and a susceptibility locus on chromosome 4 has recently been identified in one such family. Pancreatic cancer is believed to arise from pancreatic dysplasia, and familial pancreatic cancer kindreds represent a particularly high-risk population for whom effective screening strategies are needed. One promising strategy has used endoscopic ultrasound to detected pancreatic dysplasia in members of familial pancreatic cancer kindreds.     

Alstrom syndrome (OMIM 203800): a case report and literature review

Hereditary chronic pancreatitis (HCP) is a very rare form of early onset chronic pancreatitis. With the exception of the young age at diagnosis and a slower progression, the clinical course, morphological features and laboratory findings of HCP do not differ from those of patients with alcoholic chronic pancreatitis. As well, diagnostic criteria and treatment of HCP resemble that of chronic pancreatitis of other causes. The clinical presentation is highly variable and includes chronic abdominal pain, impairment of endocrine and exocrine pancreatic function, nausea and vomiting, maldigestion, diabetes, pseudocysts, bile duct and duodenal obstruction, and rarely pancreatic cancer. Fortunately, most patients have a mild disease. Mutations in the PRSS1 gene, encoding cationic trypsinogen, play a causative role in chronic pancreatitis. It has been shown that the PRSS1 mutations increase autocatalytic conversion of trypsinogen to active trypsin, and thus probably cause premature, intrapancreatic trypsinogen activation disturbing the intrapancreatic balance of proteases and their inhibitors. Other genes, such as the anionic trypsinogen (PRSS2), the serine protease inhibitor, Kazal type 1 (SPINK1) and the cystic fibrosis transmembrane conductance regulator (CFTR) have been found to be associated with chronic pancreatitis (idiopathic and hereditary) as well. Genetic testing should only be performed in carefully selected patients by direct DNA sequencing and antenatal diagnosis should not be encouraged. Treatment focuses on enzyme and nutritional supplementation, pain management, pancreatic diabetes, and local organ complications, such as pseudocysts, bile duct or duodenal obstruction. The disease course and prognosis of patients with HCP is unpredictable. Pancreatic cancer risk is elevated. Therefore, HCP patients should strongly avoid environmental risk factors for pancreatic cancer.     

Accumulation of ceramide in the trachea and intestine of cystic fibrosis mice causes inflammation and cell death

Cystic fibrosis is a hereditary metabolic disorder caused by mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene and characterized by severe intestinal and pulmonary symptoms, in particular intestinal obstruction, pancreatic insufficiency, chronic pulmonary inflammation, and microbial lung infections. Recent studies have demonstrated an accumulation of ceramide in the lungs of cystic fibrosis patients and in several mouse models. These findings showed that pulmonary ceramide concentrations play an important role in pulmonary inflammation and infection. In this study we investigated whether ceramide concentrations are also altered in the trachea and the intestine of cystic fibrosis mice and whether an accumulation of ceramide in these organs has functional consequences that are typical of cystic fibrosis. Our findings demonstrate a marked accumulation of ceramide in tracheal and intestinal epithelial cells of cystic fibrosis mice. When acid sphingomyelinase activity is inhibited by treating cystic fibrosis mice with amitriptyline or by genetic heterozygosity of acid sphingomyelinase in cystic fibrosis mice, ceramide concentrations in the trachea and the intestine are normalized. Moreover, increased rates of cell death and increased cytokine concentrations in the trachea, the intestine, or both were normalized by the inhibition of acid sphingomyelinase activity and the concomitant normalization of ceramide concentrations. These findings suggest that ceramide plays a crucial role in inflammation and increased rates of cell death in several organs of cystic fibrosis mice.     

Proteomic analysis (GeLC-MS/MS) of ePFT-collected pancreatic fluid in chronic pancreatitis

Chronic pancreatitis is characterized by inflammation, fibrosis, pain, and loss of exocrine function of the pancreas. We aimed to identify differentially expressed proteins in the ePFT-collected pancreatic fluid from individuals with chronic pancreatitis (CP; n = 9) and controls with chronic abdominal pain not associated with the pancreas (NP; n = 9). Using GeLC-MS/MS techniques, we identified a total of 1391 different proteins in 18 pancreatic fluid samples. Of these proteins, 257 and 413 were identified exclusively in the control and chronic pancreatitis cohorts, respectively, and 721 were identified in both cohorts. Spectral counting and statistical analysis thereof revealed an additional 38 and 77 proteins that were up- or down-regulated, respectively, in the pancreatic fluid from individuals with chronic pancreatitis. As expected, gene ontology analysis illustrated that the largest percentage of differentially regulated proteins was secreted/extracellular in origin. In addition, proteins that were down-regulated with statistical significance in the chronic pancreatitis cohort were determined to have biological function of proteases, corresponding to the canonical pancreatic insufficiency associated with chronic pancreatitis. Proteins enriched in the pancreatic fluid of chronic pancreatitis patients had roles in fibrosis, inflammation, and pain, whereas digestive enzymes were significantly less abundant. Our workflow provided a mass spectrometry-based approach for the further study of the pancreatic fluid proteome, which may lead to the discovery potential biomarkers of chronic pancreatitis.     

Quantitative proteomics analysis reveals that proteins differentially expressed in chronic pancreatitis are also frequently involved in pancreatic cancer

The effective treatment of pancreatic cancer relies on the diagnosis of the disease at an early stage, a difficult challenge. One major obstacle in the development of diagnostic biomarkers of early pancreatic cancer has been the dual expression of potential biomarkers in both chronic pancreatitis and cancer. To better understand the limitations of potential protein biomarkers, we used ICAT technology and tandem mass spectrometry-based proteomics to systematically study protein expression in chronic pancreatitis. Among the 116 differentially expressed proteins identified in chronic pancreatitis, most biological processes were responses to wounding and inflammation, a finding consistent with the underlining inflammation and tissue repair associated with chronic pancreatitis. Furthermore 40% of the differentially expressed proteins identified in chronic pancreatitis have been implicated previously in pancreatic cancer, suggesting some commonality in protein expression between these two diseases. Biological network analysis further identified c-MYC as a common prominent regulatory protein in pancreatic cancer and chronic pancreatitis. Lastly five proteins were selected for validation by Western blot and immunohistochemistry. Annexin A2 and insulin-like growth factor-binding protein 2 were overexpressed in cancer but not in chronic pancreatitis, making them promising biomarker candidates for pancreatic cancer. In addition, our study validated that cathepsin D, integrin beta1, and plasminogen were overexpressed in both pancreatic cancer and chronic pancreatitis. The positive involvement of these proteins in chronic pancreatitis and pancreatic cancer will potentially lower the specificity of these proteins as biomarker candidates for pancreatic cancer. Altogether our study provides some insights into the molecular events in chronic pancreatitis that may lead to diverse strategies for diagnosis and treatment of these diseases.     

Molecular understanding of chronic pancreatitis: a perspective on the future.

Despite the recent development of medical imaging technology, chronic pancreatitis can only be diagnosed when the disease is fully established. This is due to the lack of specific and sensitive markers for this disease. The discovery of mutations in the cationic trypsinogen gene in patients with hereditary pancreatitis and a high incidence of mutations in the cystic fibrosis transmembrane conductance regulator gene in patients with chronic pancreatitis might be important clues to understanding the molecular mechanisms of this disease. The interaction between ethanol and ion channels might be the missing link between alcohol ingestion and chronic pancreatitis.     

Pancreatic secretory trypsin inhibitor I reduces the severity of chronic pancreatitis in mice overexpressing interleukin-1β in the pancreas

IL-1β is believed to play a pathogenic role in the development of pancreatitis. Expression of human IL-1β in pancreatic acinar cells produces chronic pancreatitis, characterized by extensive intrapancreatic inflammation, atrophy, and fibrosis. To determine if activation of trypsinogen is important in the pathogenesis of chronic pancreatitis in this model, we crossed IL-1β transgenic [Tg(IL1β)] mice with mice expressing a trypsin inhibitor that is normally produced in rat pancreatic acinar cells [pancreatic secretory trypsin inhibitor (PTSI) I]. We previously demonstrated that transgenic expression of PSTI-I [Tg(Psti1)] increased pancreatic trypsin inhibitor activity by 190%. Tg(IL1β) mice were found to have marked pancreatic inflammation, characterized by histological changes, including acinar cell loss, inflammatory cell infiltration, and fibrosis, as well as elevated myeloperoxidase activity and elevated pancreatic trypsin activity, as early as 6 wk of age. In contrast to Tg(IL1β) mice, pancreatitis was significantly less severe in dual-transgenic [Tg(IL1β)-Tg(Psti1)] mice expressing IL-1β and PSTI-I in pancreatic acinar cells. These findings indicate that overexpression of PSTI-I reduces the severity of pancreatitis and that pancreatic trypsin activity contributes to the pathogenesis of an inflammatory model of chronic pancreatitis.     

Proteomics portrait of archival lesions of chronic pancreatitis

Chronic pancreatitis is a chronic inflammatory disorder of the pancreas. The etiology is multi-fold, but all lead to progressive scarring and loss of pancreatic function. Early diagnosis is difficult; and the understanding of the molecular events that underlie this progressive disease is limited. In this study, we investigated differential proteins associated with mild and severe chronic pancreatitis in comparison with normal pancreas and pancreatic cancer. Paraffin-embedded formalin-fixed tissues from five well-characterized specimens each of normal pancreas (NL), mild chronic pancreatitis (MCP), severe chronic pancreatitis (SCP) and pancreatic ductal adenocarcinoma (PDAC) were subjected to proteomic analysis using a "label-free" comparative approach. Our results show that the numbers of differential proteins increase substantially with the disease severity, from mild to severe chronic pancreatitis, while the number of dysregulated proteins is highest in pancreatic adenocarcinoma. Important functional groups and biological processes associated with chronic pancreatitis and cancer include acinar cell secretory proteins, pancreatic fibrosis/stellate cell activation, glycoproteins, and inflammatory proteins. Three differential proteins were selected for verification by immunohistochemistry, including collagen 14A1, lumican and versican. Further canonical pathway analysis revealed that acute phase response signal, prothrombin activation pathway, and pancreatic fibrosis/pancreatic stellate cell activation pathway were the most significant pathways involved in chronic pancreatitis, while pathways relating to metabolism were the most significant pathways in pancreatic adenocarcinoma. Our study reveals a group of differentially expressed proteins and the related pathways that may shed light on the pathogenesis of chronic pancreatitis and the common molecular events associated with chronic pancreatitis and pancreatic adenocarcinoma.     

Lithostathine messenger RNA expression in different types of chronic pancreatitis

Lithostathine may play a physiological role in preventing the precipitation of excess calcium in the pancreatic juice. The hypothesis has been advanced that in chronic calcifying pancreatitis the abnormal biosynthesis of lithostathine might be the original defect to which genetic proneness to the disease may be ascribed. The aim of the present work was to study lithostathine messenger RNA expression in the pancreas of patients with different types of pancreatitis. Lithostathine and chymotrypsinogen mRNA were determined in surgical specimens obtained from the pancreases of the following subjects: (a) 13 patients with chronic alcoholic pancreatitis (84.6% calcified); (b) 4 patients with chronic hereditary pancreatitis (all calcified); (c) 6 patients with chronic obstructive pancreatitis (4 calcified); and (d) 27 subjects suffering from pancreatic cancer. Significantly lower concentrations of both mRNAs were found in the pancreases of chronic pancreatitis patients than in non-cancerous tissue from pancreatic cancer subjects. However, about 70% of the pancreatic cancer subjects showed lithostathine and chymotrypsinogen mRNA levels comparable to those of chronic pancreatitis patients. These results indicate that the decrease in the level of mRNA is not specific to lithostathine and it is unrelated to the presence of pancreatic stones.     

Reduction of inflammation and chronic tissue damage by omega-3 fatty acids in fat-1 transgenic mice with pancreatitis

Pancreatitis is a severe debilitating disease with high morbidity and mortality. Treatment is mostly supportive, and until now there are no clinically useful strategies for anti-inflammatory therapy. Although omega-3 polyunsaturated fatty acids (n-3 PUFA) are known to have anti-inflammatory effects, the utility of these fatty acids in the alleviation of pancreatitis remained to be investigated. The aim of this study was to examine the effect of n-3 PUFA on both acute and chronic pancreatitis in a well-controlled experimental system. We used the fat-1 transgenic mouse model, characterized by endogenously increased tissue levels of n-3 PUFA, and their wild-type littermates to examine the effect of n-3 PUFA on both acute and chronic cerulein-induced pancreatitis. Disease activity and inflammatory status were assessed by both histology and molecular methods. In acute pancreatitis, fat-1 mice showed a trend towards decreased necrosis and significantly reduced levels of plasma IL-6 levels as well as reduced neutrophil infiltration in the lung. In chronic pancreatitis there was less pancreatic fibrosis and collagen content accompanied by decreased pancreatic stellate cell activation in the fat-1 animals with increased n-3 PUFA tissue levels as compared to wild-type littermates with high levels of omega-6 (n-6) PUFA in their tissues. Our data provide evidence for a reduction of systemic inflammation in acute pancreatitis and of tissue fibrosis in chronic pancreatitis by increasing the tissue content of omega-3 polyunsaturated fatty acids. These results suggest a beneficial potential for n-3 PUFA supplementation in acute and particularly chronic pancreatitis.     

抗胰腺星状细胞药物研究进展

慢性胰腺炎传统治疗方法效果不确定,需要寻找新型有效药物。活化的胰腺星状细胞在胰腺纤维化过程中起了重要的作用,使之成为新的治疗靶点。活化PSC的物质分为三类,即炎症介质、氧化应激和毒素。本文就近年来针对以上不同活化PSC的介质和相关通路的抗星状细胞药物进行综述。     

Proinflammatory cytokines: an insight into pancreatic oncogenesis

Pancreatic cancer is a highly lethal disease, being one of the five leading death causes among oncologic patients. It is usually diagnosed late due to the paucity of clinical signs, and the current therapy means have limited success. One of the documented risk factors for developing pancreatic adenocarcinoma is chronic pancreatitis. It is postulated that a chronic inflammatory disease has a potential of evolving toward neoplasia, a fact that could account for a percentage of the pancreatic cancers. Starting from this assumption, we intended to analyze the serum reflection of some molecules with proinflammatory roles, and compare them in healthy individuals, in patients with chronic pancreatitis and with pancreatic adenocarcinoma. Additionally, we performed a biochemical and hematological assessment of the study groups, and compared the results with the immunological parameters analyzed in the same subjects. We found significantly higher levels of Tumor Necrosis Factor-alpha and Interleukin 6 in chronic pancreatitis and pancreatic adenocarcinoma sera (with higher levels in the pancreatitis group than in the cancer group), compared to healthy controls. Additionally, we found significantly higher levels of interleukin 8 and Macrophage Inflammatory Protein-3 alpha in pancreatic cancer, compared to chronic pancreatitis and controls. We also identified numerous correlations between the abovementioned cytokines/chemokines and biochemical parameters, not very much studied before. Our results plead for a pathogenic role of chronic inflammation in pancreatic carcinogenesis, thus offering a potential tool for earliy diagnose or targets for therapy.     

Pancreatitis severity in mice with impaired CFTR function but pancreatic sufficiency is mediated via ductal and inflammatory cells-Not acinar cells

Mutations in the cystic fibrosis transmembrane conductance regulator gene (CFTR) are an established risk factor for cystic fibrosis (CF) and chronic pancreatitis. Whereas patients with CF usually develop complete exocrine pancreatic insufficiency, pancreatitis patients with CFTR mutations have mostly preserved exocrine pancreatic function. We therefore used a strain of transgenic mice with significant residual CFTR function (CFTR^tm1HGU) to induce pancreatitis experimentally by serial caerulein injections. Protease activation and necrosis were investigated in isolated acini, disease severity over 24h, pancreatic function by MRI, isolated duct stimulation and faecal chymotrypsin, and leucocyte function by ex vivo lipopolysaccharide (LPS) stimulation. Pancreatic and lung injury were more severe in CFTR^tm1HGU but intrapancreatic trypsin and serum enzyme activities higher than in wild-type controls only at 8h, a time interval previously attributed to leucocyte infiltration. CCK-induced trypsin activation and necrosis in acini from CFTR^tm1HGU did not differ from controls. Fluid and bicarbonate secretion were greatly impaired, whereas faecal chymotrypsin remained unchanged. LPS stimulation of splenocytes from CFTR^tm1HGU resulted in increased INF-γ and IL-6, but decreased IL-10 secretion. CFTR mutations that preserve residual pancreatic function significantly increase the severity of experimental pancreatitis—mostly via impairing duct cell function and a shift towards a pro-inflammatory phenotype, not by rendering acinar cells more susceptible to pathological stimuli.     

The noninvasive biochemical diagnosis of gastrointestinal disease, with special reference to children

Invasive tests to diagnose patients with gastrointestinal disease are rapidly being replaced by procedures which enable organ function to be assessed by monitoring the product of a metabolic reaction in readily available materials such as breath, blood, and urine. Examples of these approaches that will be assessed in this review include the hydrogen breath test for lactase deficiency, radioactive carbon dioxide breath measurements to test for fat digestion and absorption, and tests of pancreatic function based upon synthetic substrates from which fluorescein or para-aminobenzoic acid can be liberated by pancreas-specific enzymes. Significant advances have been made in improving the organ sensitivity of enzyme determinations. The determination of amylase isoenzymes has been less useful than the measurement of immunoreactive trypsin; this latter enzyme is greatly elevated in the blood of neonates with cystic fibrosis, whereas serum levels are greatly depressed in cystic fibrosis patients with pancreatic insufficiency as well as in most patients with steatorrhea due to chronic pancreatitis. Many of these tests are now becoming standard procedures in the investigation of infants with gastrointestinal disease.     

Acinar cells and the development of pancreatic fibrosis

Pancreatic fibrosis is caused by excessive deposition of extracellular matrixes of collagen and fibronectin in the pancreatic tissue as a result of repeated injury often seen in patients with chronic pancreatic diseases. The most common causative conditions include inborn errors of metabolism, chemical toxicity and autoimmune disorders. Its pathophysiology is highly complex, including acinar cell injury, acinar stress response, duct dysfunction, pancreatic stellate cell activation, and persistent inflammatory response. However, the specific mechanism remains to be fully clarified. Although the current therapeutic strategies targeting pancreatic stellate cells show good efficacy in cell culture and animal models, they are not satisfactory in the clinic. Without effective intervention, pancreatic fibrosis can promote the transformation from pancreatitis to pancreatic cancer, one of the most lethal malignancies. In the normal pancreas, the acinar component accounts for 82% of the exocrine tissue. Abnormal acinar cells may activate pancreatic stellate cells directly as cellular source of fibrosis or indirectly via releasing various substances and initiate pancreatic fibrosis. A comprehensive understanding of the role of acinar cells in pancreatic fibrosis is critical for designing effective intervention strategies. In this review, we focus on the role of and mechanisms underlying pancreatic acinar injury in pancreatic fibrosis and their potential clinical significance.     

A rat model reproducing key pathological responses of alcoholic chronic pancreatitis

Although alcohol abuse is the major cause of chronic pancreatitis, the pathogenesis of alcoholic chronic pancreatitis (ACP) remains obscure. A critical obstacle to understanding the mechanism of ACP is lack of animal models. Our objective was to develop one such model. Rats were pair-fed for 8 wk ethanol or control Lieber-DeCarli liquid diet. For the last 2 wk, they received cyclosporin A (CsA; 20 mg/kg once daily) or vehicle. After 1 wk on CsA, one episode of acute pancreatitis was induced by four 20 microg/kg injections of cerulein (Cer); controls received saline. Pancreas was analyzed 1 wk after the acute pancreatitis. CsA or Cer treatments alone did not result in pancreatic injury in either control (C)- or ethanol (E)-fed rats. We found, however, that alcohol dramatically aggravated pathological effect of the combined CsA+Cer treatment on pancreas, resulting in massive loss of acinar cells, persistent inflammatory infiltration, and fibrosis. Macrophages were prominent in the inflammatory infiltrate. Compared with control-fed C+CsA+Cer rats, their ethanol-fed E+CsA+Cer counterparts showed marked increases in pancreatic NF-kappaB activation and cytokine/chemokine mRNA expression, collagen and fibronectin, the expression and activities of matrix metalloproteinase-2 and -9, and activation of pancreatic stellate cells. Thus we have developed a model of alcohol-mediated postacute pancreatitis that reproduces three key responses of human ACP: loss of parenchyma, sustained inflammation, and fibrosis. The results indicate that alcohol impairs recovery from acute pancreatitis, suggesting a mechanism by which alcohol sensitizes pancreas to chronic injury.     

Hereditary pancreatitis: report of an affected Canadian kindred and review of the disease.

Hereditary pancreatitis is an autosomal dominant disease with no other known cause. It usually begins in childhood and is characterized by recurrent attacks of abdominal pain of variable intensity and duration, followed by symptom-free periods. The diagnosis is usually made in early adult life, when pancreatic insufficiency and calcifications appear. Complications are less frequent than in nonhereditary chronic pancreatitis. There are also differences between the two forms of chronic pancreatitis in sex incidence, etiologic factors and life expectancy. In a Canadian kindred three generations are affected with hereditary pancreatitis; there are four definite and four suspected cases. More than 40 affected kindreds, including 195 proven cases and 190 suspected cases, have now been reported in the literature. Thus, hereditary pancreatitis should be considered in the differential diagnosis of chronic relapsing pancreatitis of unknown cause as well as recurrent abdominal pain in childhood.     

Prostaglandin E2 modulates TNF-alpha-induced MCP-1 synthesis in pancreatic acinar cells in a PKA-dependent manner

Cyclooxygenase (COX)-2 is increased in human chronic pancreatitis. We recently demonstrated in a model of chronic pancreatitis (WBN/Kob rat) that inhibition of COX-2 activity reduces and delays pancreatic inflammation and fibrosis. Monocyte chemoattractant protein (MCP)-1 mRNA and PGE(2) were significantly reduced, correlating with a decreased infiltration of macrophages. MCP-1 plays an important role in the recruitment of macrophages to the site of tissue injury. The aim of our study is to identify mechanisms by which macrophages and acinar cells maintain an inflammatory reaction. The expression profile of E prostanoid receptors EP(1-4) and MCP-1 was analyzed by RT-PCR from pancreatic specimens and AR42J cells. MCP-1 secretion was detected by ELISA from rat pancreatic lobuli. We determined EP(1-4) mRNA levels in WBN/Kob rats with chronic pancreatic inflammation. Individual isoforms were highly increased in rat pancreas, concurrent with MCP-1 mRNA expression. In supernatants of pancreatic lobuli and AR42J cells, MCP-1 was detectable by ELISA. In the presence of TNF-alpha, MCP-1 was upregulated. Coincubation with PGE(2) enhanced the TNF-alpha-induced MCP-1 synthesis significantly. Similarly, TNF-alpha mRNA was synergistically upregulated by TNF-alpha and PGE(2). Furthermore, the synergistic effect of TNF-alpha and PGE(2) was abolished by inhibition of PKA but not of PKC. We conclude that EP receptors are upregulated during chronic pancreatic inflammation. PGE(2) modulates the TNF-alpha-induced MCP-1 synthesis and secretion from acinar cells. This synergistic effect is controlled by PKA. This mechanism might explain the COX-2-dependent propagation of pancreatic inflammation.     

胰腺星状细胞活化相关的信号转导通路

胰腺纤维化是慢性胰腺炎（chronic pancreatitis,CP）和胰腺癌主要的病理学特征,活化的胰腺星状细胞（pancreatic stellate cells,PSCs）是公认的致胰腺纤维化的主要效应细胞。PSCs的活化涉及到几个重要的信号转导通路：有丝分裂原活化蛋白激酶（mitogen-activated protein kinases,MAPK）、磷酯酰肌醇3激酶（phosphatidylinositol 3-kinase,PI3K）=、Smad信号转导蛋白、过氧化物酶体增生物激活受体-γ（PPAR-γ）、Rho-ROCK等细胞内信号途径。探讨这些信号通路在胰腺纤维化中所起的作用对慢性胰腺炎、胰腺癌及糖尿病的治疗有重要意义。现就与PSCs激活有关的信号通路的研究结合最新进展作一综述。