Factor In Pancreatic Ductal Adenocarcinoma Research Articles

Expression of a prometastatic splice variant of osteopontin, OPNC, in human pancreatic ductal adenocarcinoma

Osteopontin (OPN) is a secreted phosphoprotein that confers on cancer cells a migratory phenotype. We demonstrated recently that nicotine, a major risk factor in pancreatic ductal adenocarcinoma (PDA), increases OPN expression in PDA cells. An OPN splice variant, OPNc, supports anchorage independence and maybe the most potent OPN isoform to convey metastatic behavior. In this study, we tested the effect of nicotine on OPNc expression and analyzed the correlation between total OPN/OPNc levels and patients' smoking history. Real-time polymerase chain reaction and ultraviolet light illumination of ethidium-bromide staining were used to examine the mRNA expression in tissue and in PDA cells treated with or without nicotine (3-300 nmol/L). OPN and OPNc were localized by immunohistochemistry, and an enzyme-linked immunosorbent assay was used to analyze OPN serum levels. Nicotine treatment of PDA cells selectively induced de novo expression of OPNc. OPNc was found in 87% of invasive PDA lesions, of which 73% were found in smokers. The levels of OPNc correlated well with higher expression levels of total OPN in the tissue and serum from patients with invasive PDA. Our data suggest that smoking and nicotine may contribute to PDA metastatic potential through promoting OPNc expression. Although the direct role of OPNc in PDA progression is not defined, OPNc may have value as a diagnostic and prognostic marker, especially in invasive PDA.

Activator Protein-1 Has an Essential Role in Pancreatic Cancer Cells and Is Regulated by a Novel Akt-Mediated Mechanism

Activator protein-1 (AP-1) regulates the expression of several genes involved in human tumorigenesis. However, there is little known about this transcription factor in pancreatic ductal adenocarcinoma. We recently found high levels of AP-1-binding activities and multiple AP-1/DNA complexes containing c-Jun, JunD, Fra1, and Fra2 in pancreatic cancer cells. Transient transfection assays indicated that AP-1 was functional and capable of transactivating its gene targets. Furthermore, a c-Jun transactivation mutant inhibited anchorage-dependent and anchorage-independent proliferation, suggesting that AP-1 had an essential role in pancreatic cancer cells. Our study also uncovered a novel mechanism by which protein kinase Akt controls c-Jun activity in pancreatic cancer cells. Indeed, distinct from its known ability to induce c-fos and fra1 and to stabilize c-Jun, Akt appeared to directly regulate the transcriptional activity of c-Jun independently of the phosphorylation sites targeted by c-Jun NH(2)-terminal kinase (Ser(63)/Ser(73)) and glycogen synthase kinase-3 (Thr(239)). Our data also suggest that growth factors might use this Akt-regulated mechanism to potently induce c-Jun targets such as cyclin D1. Collectively, our findings indicate that AP-1 has an important function in pancreatic cancer cells and provide evidence for a previously unknown Akt-mediated mechanism of c-Jun activation.

Assessment of prognostic factors in pancreatic ductal adenocarcinoma: Focus on the retroperitoneal margin

e15670 Background: Pancreatic ductal adenocarcinoma (PDA) is a leading cause of cancer death in the West, with a nearly superimposable incidence and mortality. Resection is the only chance for cure, and various features in resection specimens correlate with outcome. While most consider the uncinate margin (UM) to be the true retroperitoneal margin, it has been suggested that the posterior pancreatic surface (PPS) may also be important. At another site with a retroperitoneal margin (i.e. rectum), 1 mm margins are significant. We thus evaluated margin status in various ways, focusing on the retroperitoneal region and emphasizing outcome. Methods: We identified all pancreaticoduodenectomies for PDA over a 6 year period in which the PPS was histologically evaluable. Tumors were assessed for the following: size, stage, grade, lymph node (LN) status, vascular and perineural invasion, and margin status. Margin status was evaluated in 3 ways: traditional margins (tumor at pancreatic neck, bile duct, and/or uncinate margins), 1 mm margins (traditional + tumor within 1 mm of UM), and PPS margins (traditional + tumor within 1 mm of PPS or UM). Kaplan-Meier survival curves were constructed with univariate factors compared by log rank analysis; multivariate analysis was done using the Cox proportional hazard model. Results: Fifty-one tumors exhibited the following features: size (mean 3.3 cm), stage (48 T3), grade (27 low, 24 high), LN status (11 neg, 40 pos), positive margins (13 traditional, 23 1 mm, and 32 PPS). Nearly all tumors exhibited at least focal vascular and perineural invasion. Grade influenced survival (p=0.0001), while size (p=0.417) and traditional and PPS margins did not (p=0.5 and 0.95). LN status and 1 mm margins trended toward significance (p=0.17 and 0.2). Conclusions: Use of a two-tiered grading system is highly correlated with survival. Neither tumor size, LN status, nor traditional or PPS margins are significant, while 1 mm margins trend toward significance. Although lack of significance of some features (i.e. size, LN status, and traditional margin status) may be attributable to modest sample size, lack of significance of the PPS may reflect its anatomic nature (i.e. not a true surgical margin). Additional study of 1 mm margins in a larger tumor set is warranted. No significant financial relationships to disclose.

Glucose transporter-1 expression and prognostic significance in pancreatic carcinogenesis.

The purposes of this study were to evaluate the prognostic significance of Glut-1 expression in patients with pancreatic ductal adenocarcinoma, and to analyse its expression in pancreatic intraepithelial neoplasias (PanIN) and non invasive intraductal papillary mucinous neoplasms (IPMN). Glut-1 expression was studied by immunohistochemistry in 60 pancreatic ductal adenocarcinomas and scored on a 4-point scale (1: <25%; 2: 25-50%; 3: 50-75%; 4: >75%). Relationships between Glut-1 score, histological grade and MIB-1 score were evaluated by the Spearman rank correlation test. Significant correlations were found between Glut-1 expression and histological grade (P<0.001) and MIB-1 score (P<0.01). Significant prognostic factors by univariate analysis were stage (P<0.0001), histological grade (P<0.001) and Glut-1 expression (P<0.005). Independent prognostic factors after multivariate analysis were stage (P<0.001) and Glut-1 expression (P<0.05), stratified as <50% and >50%. The correlation of Glut-1 score with histological grade and MIB-1 score indicated a higher glucose uptake in poorly differentiated and highly proliferative pancreatic cancer cells. Glut-1 immunohistochemical expression provides a useful prognostic factor in pancreatic ductal adenocarcinoma. Glut-1 expression was not found in PanINs 1 but in 27.8% and 43.8% of PanINs 2 and 3, and was not found in IPMNs with low- and moderate-grade dysplasia but in 60% of IPMNs with high-grade dysplasia, indicating Glut-1 involvement in a relatively early phase of pancreatic carcinogenesis.

Preoperative platelet count and survival prognosis in resected pancreatic ductal adenocarcinoma.

High platelet counts are associated with an adverse effect on survival in various neoplastic entities. The prognostic relevance of preoperative platelet count in pancreatic cancer has not been clarified. We performed a retrospective review of 205 patients with ductal adenocarcinoma who underwent surgical resection between 1990 and 2003. Demographic, surgical, and clinicopathologic variables were collected. A cutoff of 300,000/mul was used to define high platelet count. Of the 205 patients, 56 (27.4%) had a high platelet count, whereas 149 patients (72.6%) comprised the low platelet group. The overall median survival was 17 (2-178) months. The median survival of the high platelet group was 18 (2-137) months, and that of the low platelet group was 15 (2-178) months (p = 0.7). On multivariate analysis, lymph node metastasis, vascular invasion, positive margins, and CA 19-9 > 200 U/ml were all significantly associated with poor survival. There is no evidence to support preoperative platelet count as either an adverse or favorable prognostic factor in pancreatic ductal adenocarcinoma. Use of 5-year actual survival data confirms that lymph node metastases, positive margins, vascular invasion, and CA 19-9 are predictors of poor survival in resected pancreatic cancer.

Predictive factors in pancreatic ductal adenocarcinoma: Role of the inflammatory response

Objective. Pancreatic ductal adenocarcinoma is a highly lethal disease and most patients are not eligible for curable resection. Estimation of prognosis is essential in order to provide the best individual treatment for patients with pancreatic adenocarcinoma. Prediction of survival by current methods is limited, therefore the objective of this study was to determine possible prognostic factors identified at the time of diagnosis. Material and methods. All 119 consecutive patients with pancreatic ductal adenocarcinoma receiving palliative treatment at the Department of Surgery, Lund University Hospital from 1999 through 2002 were reviewed retrospectively. Prognostic factors and interventions were analysed statistically. C-reactive protein (CRP) at the time of diagnosis was measured in 109 patients. Results. The overall median survival was 4.4 months. By means of a multivariate analysis it was shown that CRP (p<0.001) and tumour size (p=0.018) were independent predictors of survival. The median survival of patients with normal CRP at the time of diagnosis was 10.8 months versus 4.2 months for those with raised CRP levels (≥5 mg/l; p<0.001). Chemotherapy was the only intervention associated with a longer survival time (p<0.001 versus no chemotherapy). Conclusions. The poor prognosis for patients with pancreatic ductal adenocarcinoma was confirmed. CRP proved to be a strong independent predictor of survival. Together with previous reported factors, CRP could serve as a potential tool to determine future treatment strategies for optimal individual palliation.

Ethanol and the Tobacco-specific Carcinogen, NNK, Contribute to Signaling in Immortalized Human Pancreatic Duct Epithelial Cells

Smoking is a well-documented risk factor for pancreatic cancer. The tobacco-specific nitrosamine, NNK (4-[methylnitrosamino]-1-[3-pyridyl]-1-butanone), significantly induces pancreatic ductal adenocarcinomas in laboratory rodents. Recent observations suggest that ethanol enhances the tumorigenic effects of smoking. Ethanol consumption is associated with the development of chronic pancreatitis, also considered a predisposing factor for pancreatic ductal adenocarcinoma. Because the precise role of ethanol in pancreatic carcinogenesis is not known, this study sought to elucidate the cumulative effects of ethanol and NNK on particular signal transduction pathways that might play a role in cell proliferation in immortalized human pancreatic duct epithelial cells. The HPDE6-c7 cells are developed from pancreatic duct epithelial cells, which are the putative cells of origin of pancreatic ductal adenocarcinoma. Cell proliferation assays, Western blot, and cyclic adenosine monophosphate assays were used to demonstrate the effects of ethanol and NNK treatments on these cells. Ethanol cotreatments enhanced the NNK-induced proliferation of these cells. This response was inhibited by the adenylyl cyclase, protein kinase A, mitogen-activated protein kinase (p42/p44), and epidermal growth factor receptor-specific tyrosine kinase inhibitors. Cotreatments of NNK and ethanol also increased cyclic adenosine monophosphate accumulation, cAMP response element-binding family of proteins and mitogen-activated protein kinase phosphorylation, and protein kinase A activation. These findings suggest a potential role for these pathways contributing to the development of smoking- and alcohol-related pancreatic carcinogenesis.

The Kinase Mirk/Dyrk1B Mediates Cell Survival in Pancreatic Ductal Adenocarcinoma

Ductal adenocarcinoma of the pancreas is almost uniformly lethal as this cancer is invariably detected at an advanced stage and is resistant to treatment. The serine/threonine kinase Mirk/Dyrk1B has been shown to be antiapoptotic in rhabdomyosarcomas. We have now investigated whether Mirk might mediate survival in another cancer in which Mirk is widely expressed, pancreatic ductal adenocarcinoma. Mirk was an active kinase in each pancreatic cancer cell line where it was detected. Mirk knockdown by RNA interference (RNAi) reduced the clonogenicity of Panc1 pancreatic cancer cells 4-fold and decreased tumor cell number, showing that Mirk mediates survival in these cells. Mirk knockdown by synthetic duplex RNAis in Panc1, AsPc1, and SU86.86 pancreatic cancer cells induced apoptosis and enhanced the apoptosis induced by gemcitibine. Mirk knockdown did not increase the abundance or activation of Akt. However, four of five pancreatic carcinoma cell lines exhibited either elevated Mirk activity or elevated Akt activity, suggesting that pancreatic cancer cells primarily rely on Mirk or Akt for survival signaling. Mirk protein was detected by immunohistochemistry in 25 of 28 cases (89%) of pancreatic ductal adenocarcinoma, with elevated expression in 11 cases (39%). Increased expression of Mirk was seen in pancreatic carcinomas compared with primary cultures of normal ductal epithelium by serial analysis of gene expression and by immunohistochemistry. Thus, Mirk is a survival factor for pancreatic ductal adenocarcinoma. Because knockout of Mirk does not cause embryonic lethality, Mirk is not essential for normal cell growth and may represent a novel therapeutic target.

O-35. Young age is not an independent prognostic factor

Immune cells are important in the pathogenesis of acute pancreatitis and determine disease severity. Results from cytokine-based clinical trials for acute pancreatitis have been disappointing, so strategies that target and alter the behavior of infiltrating immune cells require consideration. Recurrent acute pancreatitis can progress to chronic pancreatitis, which is a well-described risk factor for pancreatic ductal adenocarcinoma (PDA). However, most patients with chronic pancreatitis do not develop PDA, and most patients with PDA do not have a history of pancreatitis. Interestingly, chronic pancreatitis and PDA tissues have similarities in their desmoplasia and inflammatory infiltrates, indicating overlapping inflammatory responses. Further studies are needed to determine the differences and similarities of these responses, improve our understanding of PDA pathogenesis, and develop specific immune-based therapies. Immune cells in PDA produce immunosuppressive signals that allow tumors to evade the immune response. Unlike single therapeutic agent studies that block immunosuppressive mechanisms, studies of combination therapies that include therapeutic vaccines have provided promising results.

Prognostic Significance of Tissue Factor in Pancreatic Ductal Adenocarcinoma

Tissue factor (TF) is a transmembrane glycoprotein that plays roles in the blood coagulation and intracellular signaling pathways, and has also been suggested to modulate the biological behavior of cancer cells. In order to examine the clinicopathologic significance of TF expression in pancreatic ductal adenocarcinoma, TF expression was determined by immunohistochemistry using a newly raised anti-TF monoclonal antibody in 113 patients who had undergone surgical resection of pancreatic ductal adenocarcinoma. According to the incidence of tumor cell immunopositivity, patients were divided into "negative TF" (0%), "weak TF" (<25%), or "high TF" (25% or more) groups, which accounted for 11.6% (n = 13), 44.2% (n = 50), and 44.2% (n = 50) of the total, respectively. Increased TF expression was correlated with the extent of the primary tumor (P = 0.0043), lymph node metastasis (P = 0.0043), lymphatic distant metastasis (P = 0.0039), advanced tumor-node-metastasis stage (P = 0.0002), and high tumor grade (P = 0.0164). Multivariate analysis using the Cox proportional hazards model showed that high TF expression was an independent negative predictor for survival (hazard ratio, 2.014; P = 0.0076). Moreover, patients with TF-negative tumors had a significantly better prognosis even if lymph node metastasis was present (P < 0.0001). We also showed that TF knockdown by RNA interference suppressed the invasiveness of a pancreatic adenocarcinoma cell line in vitro. These results indicate that TF expression may contribute to the aggressiveness of pancreatic ductal adenocarcinoma by stimulating tumor invasiveness, and that evaluation of the primary tumor for TF expression may identify patients with a poor prognosis.

Predictive factors for pancreatic cancer in patients with chronic pancreatitis in association with K-ras gene mutation.

Chronic pancreatitis is considered to be a predisposing factor for pancreatic ductal adenocarcinoma (PAC). The purpose of this study was to examine the prognostic value of a finding of mutated (K- ras) gene in predicting the development of PAC in patients with chronic pancreatitis. The pancreatic duct brushings of 146 patients with chronic pancreatitis were examined in order to identify K- ras gene mutations. A total of 112 patients were followed up (median duration 42 months) using clinical evaluation, serum CA19 - 9 levels, and imaging studies. One or more K- ras mutations were found in 57 of the 146 patients with chronic pancreatitis (39 %). Patients harboring K- ras mutations had a higher incidence of persistent alcohol consumption ( P = 0.041) and of prior rupture of the main pancreatic duct ( P = 0.040). A finding of nuclear atypia in brushing cytology was also more common in patients with K- ras mutation ( P = 0.048). Out of the 112 patients who were followed up, PAC occurred in four of the 44 patients who had a K- ras mutation, but in none of the 68 patients with the wild genotype ( P = 0.022). PAC occurred in three of the 25 patients who did not have pancreatic calcifications ( P = 0.034) and in four of the 54 patients who had demonstrated exocrine insufficiency, but in none of the 58 patients with preserved exocrine function ( P = 0.051). Using stepwise logistic regression, the absence of calcifications, the presence of exocrine insufficiency, and the presence of K- ras mutation were identified as independent predictive factors for cancer development in all patients with chronic pancreatitis. K- ras gene mutations occur in chronic pancreatitis and are associated with evolution towards PAC. The absence of pancreatic calcifications and the presence of exocrine insufficiency were identified as additional predictive factors for the development of PAC.

The grade of pancreatic ductal carcinoma is an independent prognostic factor and is superior to the immunohistochemical assessment of proliferation.

Tumour grade is one of the prognostic factors in pancreatic ductal adenocarcinoma, but its value is controversial. In this study, the predictive value and the reproducibility of the WHO grading system were reconsidered and the possibility of supplementing it with the immunohistochemically assessed proliferative activity was investigated. Seventy resected ductal adenocarcinomas of the head of the pancreas were evaluated. A total of 60 HPF fields on two to four sections per tumour were screened for glandular differentiation, mucin production, mitosis, and nuclear atypia by two observers with different degrees of experience. Each criterion was scored and the grade was calculated from the mean value of all single scores. Corresponding slides were immunohistochemically stained with the proliferation marker Ki-S5. The percentage of positive nuclei was assessed and a proliferation index (PI) assigned (<10%=1; 10-50%=2; >50%=3). Multivariate analysis (Cox regression) identified grade and R stage as the most significant factors for predicting survival. The PI determined on the basis of Ki-S5 staining did not prove to be an independent prognostic factor. In 30 of 70 carcinomas, it correlated with the tumour grade. Within a given tumour grade, the cases with the least favourable prognosis could be distinguished on the basis of their PI. The inter-observer variability was considerable, with the main differences occurring in the group of G1 tumours. According to the refined WHO criteria, the histopathological grade of pancreatic ductal carcinoma is an important independent prognostic factor, but reproducibility depends on the expertise of the observer. Criteria that relate to cellular and structural differentiation seem to be more predictive than those related to proliferation.