Molecular prognostic markers in pancreatic cancer: a systematic review

Enhanced ENA-78 and IL-8 expression in patients with malignant pancreatic diseases

BACKGROUND/AIM

Pancreatic cancer is characterized by perineural invasion, early lymph node and liver metastases, and an extremely dismal prognosis. In the present study we aimed at investigating the expression profile of pro-inflammatory and angiogenic CXC chemokines as potential factors contributing to the aggressive biology of this gastrointestinal malignancy.

METHODS

Protein expression profiles of the CXC chemokines growth-related oncogene alpha (GRO-alpha/CXCL1), epithelial cell-derived neutrophil-activating peptide-78 (ENA-78/CXCL5), granulocyte chemoattractant protein-2 (GCP-2/CXCL6), neutrophil-activating protein-2 (NAP-2/CXCL7), and interleukin-8 (IL-8/CXCL8) were assessed by enzyme-linked immunosorbent assay in pancreatic carcinoma, cancer of the papilla of Vater, pancreatic cystadenoma, and chronic pancreatitis specimens.

RESULTS

IL-8 and ENA-78 protein expression was most pronounced in pancreatic carcinoma specimens, showing an 11-fold and 17-fold overexpression in comparison with non-affected neighbouring tissues, a 66-fold and 24-fold upregulation compared to pancreatic cystadenoma, and a 6-fold and 9-fold overexpression with respect to chronic pancreatitis, respectively (p < 0.05 between all groups). In addition, a close correlation between IL-8 and ENA-78 protein expression and advanced pancreatic carcinomas in relation to the T category was evident (p < 0.05).

CONCLUSION

Our results demonstrate that ELR+ CXC chemokines are differentially expressed in malignant and non-malignant human pancreatic specimens, suggesting a potential contribution of these chemokines to the pathogenesis of pancreatic carcinoma.

Tailoring to RB: tumour suppressor status and therapeutic response

The retinoblastoma tumour suppressor (RB) is a crucial regulator of cell-cycle progression that is invoked in response to a myriad of anti-mitogenic signals. It has been hypothesized that perturbations of the RB pathway confer a synonymous proliferative advantage to tumour cells; however, recent findings demonstrate context-specific outcomes associated with such lesions. Particularly, loss of RB function is associated with differential response to wide-ranging therapeutic agents. Thus, the status of this tumour suppressor may be particularly informative in directing treatment regimens.

Pancreatic ductal adenocarcinoma: cellular origin, signaling pathways and stroma contribution

Pancreatic cancer has a very poor prognosis, in part due to its diagnosis at late stages of the disease and to limited response to chemotherapy and radiotherapy. The vast majority of pancreatic cancers are classified as pancreatic ductal adenocarcinomas (PDACs). Despite advances in knowledge on the cellular origin of PDAC or the involvement of signal transduction pathways therein, many questions remain unanswered. In this review, we summarize recent findings and current hypotheses regarding these two questions. Since pancreatitis is a risk factor for human PDAC, and the latter proceeds with an intense fibrotic reaction, we also analyze the role of the stroma in PDAC progression. An improved understanding of these key aspects for PDAC ontogeny will open new avenues for tumor prevention, early detection, and improved therapy.

Analysis of microRNAs in pancreatic fine-needle aspirates can classify benign and malignant tissues

BACKGROUND

MicroRNAs (miRNAs) are RNA molecules that are involved in the regulation of many cellular processes, including those related to human cancers. The aim of this study was to determine, as a proof of principle, whether specific candidate miRNAs could be detected in fine-needle aspirate (FNA) biopsies of pancreatic ductal adenocarcinoma (PDAC) and could accurately differentiate malignant from benign pancreatic tissues.

METHODS

We used TaqMan(R) assays to quantify miRNA levels in FNA samples collected in RNARetain (n = 16) and compared the results with a training set consisting of frozen macrodissected pancreatic samples (n = 20).

RESULTS

Quantitative reverse-transcription PCR analysis confirmed that miRNA levels are affected in PDAC FNAs and correlate well with the changes observed in the training set of frozen pancreatic samples. Analysis of the amounts produced for a few specific miRNAs enabled identification of PDAC samples. The combination of miR-196a and miR-217 biomarkers further improved the ability to distinguish between healthy tissue, PDAC, and chronic pancreatitis in the training set (P = 8.2 x 10(-10)), as well as segregate PDAC FNA samples from other FNA samples (P = 1.1 x 10(-5)). Furthermore, we showed that miR-196a production is likely specific to PDAC cells and that its incidence paralleled the progression of PDAC.

CONCLUSIONS

To the best of our knowledge, this study is the first to evaluate the diagnostic potential of miRNAs in a clinical setting and has shown that miRNA analysis of pancreatic FNA biopsy samples can aid in the pathologic evaluation of suspicious cases and may provide a new strategy for improving the diagnosis of pancreatic diseases.

ArgBP2-dependent signaling regulates pancreatic cell migration, adhesion, and tumorigenicity

The poor prognosis of pancreatic cancer is due to rapid locoregional invasion, the early development of metastases, and the limited efficacy of current therapies. To date, none of the identified oncogenes and suppressors involved in this disease have led to efficient treatments. Here, we describe that the scaffold protein ArgBP2 is repressed during oncogenic transformation of the pancreas. We could show, using a pancreatic cancer cell line model, that this repression of ArgBP2 participates in the progression of this disease. Interestingly, in vitro analyses revealed that the antitumoral potential of ArgBP2 is linked to the control of cell adhesion and migration rather than to the regulation of cell proliferation or sensitivity to apoptosis. Moreover, we could detail part of the molecular mechanism responsible by identifying new ArgBP2-interacting proteins, and show that this function is partly achieved by the control of a WAVE/PTP-PEST/c-Abl signaling complex. These findings point to a new mechanism of pancreatic cancer progression leading to invasion and metastasis and suggest that the ArgBP2 signaling pathway could represent a new target for cancer therapy.

Proteomic analysis identifies MMP-9, DJ-1 and A1BG as overexpressed proteins in pancreatic juice from pancreatic ductal adenocarcinoma patients

Background

There is an urgent need to discover more sensitive and specific biomarkers to improve early diagnosis and screen high-risk patients for pancreatic ductal adenocarcinoma (PDAC). Pancreatic juice is an ideal specimen for PDAC biomarkers discovery, because it is an exceptionally rich source of proteins released from pancreatic cancer cells.

Methods

To identify novel potential biomarkers for PDAC from pancreatic juice, we carried out difference gel electrophoresis (DIGE) and tandem mass spectrometry (MS/MS) to compare the pancreatic juice profiling from 9 PDAC patients and 9 cancer-free controls. Of the identified differently expressed proteins, three up-regulated proteins in pancreatic cancer juice, matrix metalloproteinase-9 (MMP-9), oncogene DJ1 (DJ-1) and alpha-1B-glycoprotein precursor (A1BG), were selected for validation by Western blot and immunohistochemistry. Serum MMP-9 levels were also detected by enzyme linked immunosorbent assay (ELISA).

Results

Fourteen proteins were up-regulated and ten proteins were down-regulated in cancerous pancreatic juice compared with cancer-free controls. Increased MMP-9, DJ-1 and A1BG expression in cancerous pancreatic juice were confirmed by Western blot. Immunohistochemical study showed MMP-9, DJ-1 and A1BG positively expressed in 82.4%, 72.5% and 86.3% of pancreatic cancer tissues, significantly higher than that in normal pancreas tissues. Up-regulation of DJ-1 was associated with better differentiation (p < 0.05). Serum MMP-9 levels were significantly higher in PDAC (255.14 ng/ml) than those in chronic pancreatitis (210.22 ng/ml, p = 0.009) and healthy control (203.77 ng/ml, p = 0.027).

Conclusion

The present proteome analysis revealed MMP-9, DJ-1 and A1BG proteins as elevated in pancreatic juice from PDAC, which suggest their further utility in PDAC diagnosis and screening. This is the first time A1BG was identified as a potential biomarker in pancreatic cancer associated samples. The measurement of serum MMP-9 might be clinically useful for PDAC diagnosis.

Increased alternative splicing of the KLF6 tumour suppressor gene correlates with prognosis and tumour grade in patients with pancreatic cancer

The aim of this study was to correlate the status of the KLF6 tumour suppressor gene including loss of heterozygosity (LOH), mutation and alternative splicing in human pancreatic cancer with tumour grade and survival. Whereas neither KLF6 loss nor mutation was identified, expression of the KLF6 alternative splice forms was significantly increased in pancreatic tumour samples and cell lines. These cancers demonstrated marked cytoplasmic KLF6 expression, consistent with over-expression and accumulation of KLF6 splice form(s), which lack a nuclear localisation signal. In addition, KLF6 splicing correlated significantly with tumour stage and survival. In summary, pancreatic cancer displays a novel pattern of KLF6 dysregulation through selectively increased expression of KLF6 splice variants. Therefore, determination of KLF6 mRNA splicing levels may represent a novel biomarker predicting prognosis.

Serum vascular endothelial growth factor/soluble vascular endothelial growth factor receptor 1 ratio is an independent prognostic marker in pancreatic cancer

OBJECTIVES

Tumor angiogenesis is the consequence of an imbalance between positive and negative angiogenic regulatory factors. We sought to determine the role of pretreated serum angiogenic factors, including vascular endothelial growth factor (VEGF), placental growth factor (PlGF), and soluble vascular endothelial growth factor receptor 1 (sVEGFR-1), in predicting clinical outcome in patients with pancreatic cancer.

METHODS

We assessed pretreated serum VEGF, PlGF, and sVEGFR-1 levels in 92 patients with pancreatic adenocarcinoma and 60 healthy control subjects using an enzyme-linked immunosorbent assay. The correlation between these angiogenesis-related factors and clinicopathologic factors, including staging and overall survival, was analyzed.

RESULTS

Serum levels of VEGF, PlGF, and sVEGFR-1 were significantly higher in patients with pancreatic cancer compared with those in controls (583.8 +/- 559.5 vs 187.63 +/- 393.32, 17.65 +/- 7.34 vs 10.93 +/- 1.21, and 50.94 +/- 51.17 vs 15.55 +/- 1.98 pg/mL, respectively; P < 0.0001). A reverse correlation was observed between sVEGFR-1 level and the advance of tumor stage. Cox regression analysis showed that the VEGF/sVEGFR-1 ratio was an independent predictor for pancreatic cancer survival. Higher VEGF/sVEGFR-1 ratio was significantly correlated with poor outcome in patents with pancreatic cancer.

CONCLUSIONS

Vascular endothelial growth factor/sVEGF-1 ratio is an independent prognostic factor for survival in pancreatic cancer. Its significance should be assessed when considering antiangiogenic therapy in treating pancreatic cancer patients.

TW-37, a small-molecule inhibitor of Bcl-2, inhibits cell growth and invasion in pancreatic cancer

Bcl-2 family of proteins plays critical roles in human cancers, including pancreatic cancer, suggesting that the discovery of specific agents targeting Bcl-2 family proteins would be extremely valuable for pancreatic cancer therapy. We have previously reported the synthesis and characterization of TW-37, which seems to be a negative regulator of Bcl-2. In this investigation, we tested our hypothesis whether TW-37 could be an effective inhibitor of cell growth, invasion and angiogenesis in pancreatic cancer cells. Using multiple cellular and molecular approaches such as MTT assay, apoptosis enzyme-linked immunosorbent assay, real-time reverse transcription-polymerase chain reaction, Western blotting, electrophoretic mobility shift assay for measuring DNA binding activity of NF-kappaB, migration, invasion and angiogenesis assays, we found that TW-37, in nanomolar concentrations, inhibited cell growth in a dose- and time-dependent manner. This was accompanied by increased apoptosis and concomitant attenuation of NF-kappaB, and downregulation of NF-kappaB downstream genes such as MMP-9 and VEGF, resulting in the inhibition of pancreatic cancer cell migration, invasion and angiogenesis in vitro and caused antitumor activity in vivo. From these results, we conclude that TW-37 is a potent inhibitor of progression of pancreatic cancer cells, which could be due to attenuation of Bcl-2 cellular signaling processes. Our findings provide evidence showing that TW-37 could act as a small-molecule Bcl-2 inhibitor on well-characterized pancreatic cancer cells in culture as well as when grown as tumor in a xenograft model. We also suggest that TW-37 could be further developed as a potential therapeutic agent for the treatment of pancreatic cancer.

In vivo optical molecular imaging of vascular endothelial growth factor for monitoring cancer treatment

PURPOSE

Vascular endothelial growth factor (VEGF) expression is a critical component in tumor growth and metastasis. Capabilities to monitor VEGF expression in vivo can potentially serve as a useful tool for diagnosis, prognosis, treatment planning, monitoring, and research. Here, we present the first report of in vivo hyperspectral molecular imaging strategy capable of monitoring treatment-induced changes in VEGF expression.

EXPERIMENTAL DESIGN

VEGF was targeted with an anti-VEGF antibody conjugated with a fluorescent dye and was imaged in vivo using a hyperspectral imaging system. The strategy was validated by quantitatively monitoring VEGF levels in three different tumors as well as following photodynamic treatment. Specificity of the molecular imaging strategy was tested using in vivo competition experiments and mathematically using a quantitative pharmacokinetic model.

RESULTS

The molecular imaging strategy successfully imaged VEGF levels quantitatively in three different tumors and showed concordance with results from standard ELISA. Changes in tumoral VEGF concentration following photodynamic treatment and Avastin treatment were shown. Immunohistochemistry shows that (a) the VEGF-specific contrast agent labels both proteoglycan-bound and unbound VEGF in the extracellular space and (b) the bound VEGF is released from the extracellular matrix in response to photodynamic therapy. In vivo competition experiments and quantitative pharmacokinetic model-based analysis confirmed the high specificity of the imaging strategy.

CONCLUSION

This first report of in vivo quantitative optical molecular imaging-based monitoring of a secreted cytokine in tumors may have implications in providing tools for mechanistic investigations as well as for improved treatment design and merits further investigation.

Pancreatic carcinogenesis

Pancreatic cancer is an almost universally lethal disease. Research over the last two decades has shown that pancreatic cancer is fundamentally a genetic disease, caused by inherited germline and acquired somatic mutations in cancer-associated genes. Multiple alterations in genes that are important in pancreatic cancer progression have been identified, including tumor suppressor genes, oncogenes, and genome maintenance genes. Furthermore, the identification of noninvasive precursor lesions of pancreatic adenocarcinoma has led to the formulation of a multi-step progression model of pancreatic cancer and the subsequent identification of early and late genetic alterations culminating in invasive cancer. In addition, an increased understanding of the molecular basis of the disease has facilitated the identification of new drug targets enabling rational drug design. The elucidation of genetic alterations in combination with the development of high-throughput sensitive techniques should lead to the discovery of effective biomarkers for early detection of this malignancy. This review focuses mainly on the current knowledge about the molecular insights of the pathogenesis of pancreatic ductal adenocarcinoma.

Proteomics of pancreatic cancer

Pancreatic cancer is a devastating disease, with a mortality rate almost identical with its incidence. Late diagnosis and limited therapeutic options make early detection of pancreatic cancer a pressing clinical problem. In this context, the investigation of the pancreatic cancer proteome has recently gained considerable attention because profiles of proteins may be able to more accurately identify disease states, such as cancer. Recent pancreatic cancer proteome studies may be categorized into basic studies cataloguing the pancreatic proteome, studies investigating differential protein expression patterns, and studies searching for proteome-based biomarkers for early cancer detection and differentiation. Although these studies clearly demonstrate that a range of biological samples are suitable for proteomic analyses, comparison of different studies is problematic due to the diversity of methodologies, sample sources, and characterization of patient populations. Reproducibility between studies has rarely been investigated, and no investigation has compared the different methods of proteomic research. The results of this review have shown that more stringent requirements concerning the design and the analysis of future studies should be implemented. These include an adequate patient number, obligatory histological examination of tissues, appropriate control groups, identification of proteins and peaks, validation of differential expression using independent cohorts and/or a second methodology, and, finally, demonstration of result reproducibility. This will hopefully lead to the discovery of prognostic and predictive biomarkers that help to improve prognosis of pancreatic cancer patients.

Evaluation of pancreatic cancer with Raman spectroscopy in a mouse model

OBJECTIVES

Detection of neoplastic changes using optical spectroscopy has been an active area of research in recent times. Raman spectroscopy is a vibrational spectroscopic technique that can be used to diagnose various tumors with high sensitivity and specificity. We evaluated the ability of Raman spectroscopy to differentiate normal pancreatic tissue from malignant tumors in a mouse model.

METHODS

We collected 920 spectra, 475 from 31 normal pancreatic tissue and 445 from 29 tumor nodules using a 785-nm near-infrared laser excitation. Discriminant function analysis was used for classification of normal and tumor samples.

RESULTS

Using principal component analysis, we were able to highlight subtle chemical differences in normal and malignant tissue. Using histopathology as the gold standard, Raman analysis gave sensitivities between 91% and 96% and specificities between 88% and 96%.

CONCLUSIONS

Raman spectroscopy along with discriminant function analysis is a useful method to detect cancerous changes in the pancreas. Pancreatic tumors were characterized by increased collagen content and decreased DNA, RNA, and lipids components compared with normal pancreatic tissue.

Prognostic significance of growth factors and the urokinase-type plasminogen activator system in pancreatic ductal adenocarcinoma

OBJECTIVES

To determine the diagnostic and prognostic significance of growth factors and the urokinase-type plasminogen activator (uPA) system in pancreatic ductal adenocarcinoma (PDAC) using a multigene assay.

METHODS

Messenger RNA (mRNA) expression of 15 genes from epidermal growth factor receptor, insulin-like growth factor (IGF), and uPA families were measured in 46 PDAC tissue samples using quantitative real-time reverse transcription-polymerase chain reaction. These results were compared with those of the uninvolved adjacent (AP) tissue and benign mucinous cystadenomas (BMC). The mRNA expression was evaluated using logistic regression and receiver operating characteristic area under the curve (ROC AUC) analyses. Their relationship with prognosis was tested by Cox regression multivariate analysis.

RESULTS

All genes were overexpressed in most of the PDAC tissue. When compared with AP tissue, the median expression values for IGF-binding protein 3 (IGFBP-3) and uPA receptor (uPAR) was 9.8- and 9.6-fold, respectively. Expression levels of uPA, uPAR, IGF-I, and IGFBP-3 mRNA were significantly greater in PDAC than in BMC. The IGFBP-3 mRNA expression demonstrated greatest ROC AUC values for PDAC versus AP tissue (ROC AUC, 0.745; 95% confidence interval [CI], 0.65-0.86); whereas ROC AUC values were greatest for uPAR when PDAC was compared with BMC (ROC AUC, 0.846; 95% CI, 0.76-0.94). The combination of uPA, uPAR, and IGF-I significantly improved discriminatory power (ROC AUC, 0.965; 95% CI, 0.93-1.00). The IGFBP-3, uPA, plasminogen activator inhibitor-2, and International Union Against Cancer stage had a significant influence on survival, but the effect of IGFBP-3 was lost after multivariate stepwise analysis.

CONCLUSIONS

These results indicate that there is an influence of IGF system in tumor progression from BMC to PDAC, whereas the uPA/uPAR system has the greater influence on survival in PDAC.

Immunohistochemical analysis of changes in signaling pathway activation downstream of growth factor receptors in pancreatic duct cell carcinogenesis

Background

The pathogenesis of pancreatic ductal adenocarcinoma (PDAC) involves multi-stage development of molecular aberrations affecting signaling pathways that regulate cancer growth and progression. This study was performed to gain a better understanding of the abnormal signaling that occurs in PDAC compared with normal duct epithelia.

Methods

We performed immunohistochemistry on a tissue microarray of 26 PDAC, 13 normal appearing adjacent pancreatic ductal epithelia, and 12 normal non-PDAC ducts. We compared the levels of 18 signaling proteins including growth factor receptors, tumor suppressors and 13 of their putative downstream phosphorylated (p-) signal transducers in PDAC to those in normal ductal epithelia.

Results

The overall profiles of signaling protein expression levels, activation states and sub-cellular distribution in PDAC cells were distinguishable from non-neoplastic ductal epithelia. The ERK pathway activation was correlated with high levels of ^S2448p-mTOR (100%, p = 0.05), ^T389p-S6K (100%, p = 0.02 and ^S235/236p-S6 (86%, p = 0.005). Additionally, ^T389p-S6K correlated with ^S727p-STAT3 (86%, p = 0.005). Advanced tumors with lymph node metastasis were characterized by high levels of ^S276p-NFκB (100%, p = 0.05) and ^S9p-GSK3β (100%, p = 0.05). High levels of PKBβ/AKT2, EGFR, as well as nuclear ^T202/Y204p-ERK and ^T180/Y182p-p38 were observed in normal ducts adjacent to PDAC compared with non-cancerous pancreas.

Conclusion

Multiple signaling proteins are activated in pancreatic duct cell carcinogenesis including those associated with the ERK, PKB/AKT, mTOR and STAT3 pathways. The ERK pathway activation appears also increased in duct epithelia adjacent to carcinoma, suggesting tumor micro-environmental effects.

Microarray Technologies for Gene Transcript Analysis in Pancreatic Cancer

Pancreatic cancer is a devastating condition that is most often characterized by a poor prognosis. Microarray technologies are promising screening methods for the identification of potential markers for early diagnosis and chemotherapeutic intervention. In this article, we review the current state of pancreatic cancer research as it relates to the measurement of gene transcript levels by DNA microarray analysis.

TPS, CA 19-9, VEGF-A, and CEA as diagnostic and prognostic factors in patients with mass lesions in the pancreatic head

INTRODUCTION

Although numerous tumour markers are available for periampullary tumours, including pancreatic cancer, their specificity and sensitivity have been questioned.

MATERIALS AND METHODS

To assess the diagnostic and prognostic values of tissue polypeptide specific antigen (TPS), carbohydrate antigen 19-9 (CA 19-9), vascular endothelial growth factor (VEGF-A), and carcinoembryonic antigen (CEA) we took serum samples in 56 patients with mass lesions in the pancreatic head. Among these patients, further investigations revealed pancreatic cancer in 20 patients, other malignant diseases in 12 and benign conditions in 24.

RESULTS

Median CEA in all patients was 3.4 microg/L (range 0.5-585.0), median CA 19-9 was105 kU/L (range 0.6-1 300 00), median TPS 123.5 U/L (range 15.0-3350) and median VEGF-A 132.5 ng/L (range 60.0-4317). Area under the curve was 0.747, standard error (standard error [SE] =0.075) for CEA, 0.716 (SE=0.078) for CA 19-9 and 0.822 (SE=0.086) for TPS in ROC plots based on the ability of the tumours to distinguish between benign and malignant conditions. None of the markers significantly predicted survival in the subgroup of patients with pancreatic cancer.

DISCUSSION

Our study shows that the markers may be used as fairly reliable diagnostic tools, but cannot be used to predict survival.

3D radiotherapy can be safely combined with sandwich systemic gemcitabine chemotherapy in the management of pancreatic cancer: factors influencing outcome

PURPOSE

The aim of this Phase II study was to examine whether concurrent continuous infusion 5-fluorouracil (CI 5FU) plus three-dimensional conformal planning radiotherapy sandwiched between gemcitabine chemotherapy is effective, tolerable, and safe in the management of pancreatic cancer.

METHODS AND MATERIALS

Patients were enrolled in two strata: (1) resected pancreatic cancer at high risk of local relapse (postsurgery arm, n = 22) or (2) inoperable pancreatic cancer in head or body without metastases (locally advanced arm, n = 41). Gemcitabine was given at 1,000 mg/m(2) weekly for 3 weeks followed by 1 week rest then 5-6 weeks of radiotherapy and concurrent CI 5FU (200 mg/m(2)/day). After 4 weeks' rest, gemcitabine treatment was reinitiated for 12 weeks.

RESULTS

For the two arms combined, treatment-related Grade 3 and 4 toxicities were reported by 25 (39.7%) and 7 (11.1%) patients, respectively. No significant late renal or hepatic toxicity was observed. In the postsurgery arm (R1 54.5%), median time to progressive disease from surgery was 11.0 months, median time to failure of local control was 32.9 months, and median survival time was 15.6 months. The 1- and 2-year survival rates were 63.6% and 31.8%. No significant associations between outcome and mutations in K-ras or TP53 or microsatellite instability were identified. Post hoc investigation of cancer antigen 19-9 levels found baseline levels and increases postbaseline were associated with shorter survival (p = 0.0061 and p < 0.0001, respectively).

CONCLUSIONS

This three-dimensional chemoradiotherapy regimen is safe and promising, with encouraging local control for a substantial proportion of patients, and merits testing in a randomized trial.

CXCL14 expression and potential function in pancreatic cancer

CXC chemokines influence angiogenesis, growth, and metastatic potential of pancreatic cancer. Therefore, the expression and potential function of CXCL14, a recently described CXC chemokine, was evaluated. CXCL14 is upregulated in pancreatic cancer tissues compared to chronic pancreatitis and normal pancreas. Immunolocalization revealed a distinct expression of CXCL14 in tubular complexes in chronic pancreatitis and in particular at the invasive front of pancreatic cancer tissues. Stimulation of pancreatic cancer cells with CXCL14 showed no effects on cell viability and on chemosensitivity. However, CXCL14 clearly increased invasiveness of pancreatic cancer cells without affecting MMP-2 and VEGF secretion, whereas CXCL14 influenced NFkB p65 levels. In conclusion, CXCL14 might play a pivotal role in the pathobiology of pancreatic cancer, probably by regulating cancer invasion.

Increased expression of matrix metalloproteinases-21 and -26 and TIMP-4 in pancreatic adenocarcinoma

Pancreatic adenocarcinoma is known for early aggressive local invasion, high metastatic potential, and a low 5-year survival rate. Matrix metalloproteinases (MMPs) play important roles in tumor growth and invasion. Earlier studies on pancreatic cancer have found increased expression of certain MMPs to correlate with poorer prognosis, short survival time or presence of metastases. We studied the expression of MMP-21, -26, and tissue inhibitor of matrix metalloproteinases (TIMP)-4 in 50 tissue samples, including 25 adenocarcinomas, seven other malignant pancreatic tumors, and 18 control samples of non-neoplastic pancreatic tissue with immunohistochemistry. The regulation of MMP-21, -26, and TIMP-4 mRNAs by cytokines was studied with RT-PCR in pancreatic cancer cell lines PANC-1, BxPC-3, and AsPC-1. MMP-21, -26, and TIMP-4 were detected in cancer cells in 64, 40, and 60% of tumors, respectively. MMP-21 expressed in well-differentiated cancer cells and occasional fibroblasts, like TIMP-4, tended to diminish in intensity from grade I to grade III tumors. Patients with metastatic lymph nodes had increased expression of MMP-26 in actual tumor samples. All cultured cancer cell lines expressed MMP-21 basally at low levels, and presence of the protein was confirmed immunohistochemically in cultured cells. MMP-21 expression was induced by epidermal growth factor (EGF) in PANC-1 cells. MMP-26 was neither expressed basally nor induced by tumor necrosis factor alpha, transforming growth factor beta-1 (TGFbeta1), EGF, or interferon gamma. Basal TIMP-4 expression was lowest in the poorly differentiated cancer cell line PANC-1 compared to better-differentiated BxPC-3 and AsPC-1 cells. TIMP-4 expression was induced by TGFbeta1 in PANC-1 cells and by EGF in BxPC-3 cells. Our findings suggest that MMP-21 is not a marker of invasiveness, but rather of differentiation, in pancreatic cancer and it may be upregulated by EGF. The putative role of MMP-26 as a marker of metastases warrants further studies. Unlike other TIMPs, TIMP-4 was not upregulated in relation to aggressiveness of pancreatic cancer.

Mechanisms of Disease: chronic inflammation and cancer in the pancreas—a potential role for pancreatic stellate cells?

Late diagnosis and ineffective therapeutic options mean that pancreatic ductal adenocarcinoma (PDA) is one of the most lethal forms of human cancer. The identification of genetic alterations facilitated the launch of the Pancreatic Intraepithelial Neoplasm nomenclature, a standardized classification system for pancreatic duct lesions, but the factors that contribute to the development of such lesions and their progression to high-grade neoplasia remain obscure. Age, smoking, obesity and diabetes confer increased risk of PDA, and the presence of chronic pancreatitis is a consistent risk factor for pancreatic cancer. It is hypothesized that chronic inflammation generates a microenvironment that contributes to malignant transformation in the pancreas, as is known to occur in other organs. Pancreatic stellate cells (PSCs) are the main mediator of fibrogenesis during chronic pancreatitis, but their contribution to the development of PDA has not been elucidated. Data now suggest that PSCs might assume a linking role in inflammation-associated carcinogenesis through their ability to communicate with inflammatory cells, acinar cells, and pancreatic cancer cells in a complicated network of interactions. In this Review, the role of PSCs in the process of inflammation-associated carcinogenesis is discussed and new potential treatment options evaluated.

Plasma membrane assays and three-compartment image cytometry for high content screening

High throughput image cytometers analyze individual cells in digital photomicrographs by first assigning pixels within each image to plasma membrane, cytoplasm, nucleus, or other regions. In this study, we report on a novel algorithm that: 1) identifies plasma membrane regions to measure changes in plasma membrane-associated proteins (protein kinase C [PKC] alpha, N-cadherin, E-cadherin, vascular endothelium [VE]-cadherin, and pan-cadherin) that regulate cell division, migration, and adhesion and 2) delineates the cell for generalized three-compartment image cytometry. Validation assays were performed for these proteins on cells cultured in 96-well plates and also for tissue sections obtained from transgenic and chemical carcinogenic models of skin cancer. The algorithm successfully quantified phorbol 12-myristate 13-acetate (PMA)-induced plasma membrane localization of PKCalpha in HeLa cells (Z' of 0.88). Additionally, PMA activated translocation to the plasma membrane at P < .01 of N-cadherin (in HeLa cells), E-cadherin (in A431 cells), and VE-cadherin (in human dermal microvascular endothelial cells), suggesting a relationship between PKCalpha activity and cadherin localization. For VE-cadherin, a Z' of 0.52 was obtained between serum-free medium, which increased VE-cadherin, and EGTA, which diminished VE-cadherin at the plasma membrane. For sections obtained from the transgenic skin cancer model, analysis of images with the plasma membrane algorithm revealed that tumor cells exhibited cadherin expression that was just 34% of that expressed by surrounding normal tissue; furthermore, tumor cells expressed elevated DNA content, consistent with development of aneuploidy. In contrast, increased DNA content did not occur for tumor cells produced by chemical carcinogenesis. The results demonstrate that this new algorithm for plasma membrane image cytometry enables statistically significant analyses in a variety of applications in both cultured cells and tissue sections.

MicroRNA profiles and initiation, diagnosis and treatment of cancers in digestive organs

MicroRNA (miRNA) is a kind of small non-coding RNA containin 21 to 23 nucleotides in length that down-regulates gene expression during various crucial cell processes such as development, proliferation, differentiation and apoptosis. Recent studies supported an important role of miRNA in the initiation and progression of human malignancies. Some miRNAs may function as oncogenes or tumor suppressors. It is found that several miRNAs are directly involved in human cancers of digestive organs, including liver, colon, stomach, pancreas and bile duct. In addition, miRNA expression profiling of tumors in digestive organs has identified signatures associated with diagnosis, staging, progression, prognosis and response to treatment. Profiling has also been exploited to identify miRNA genes that might represent downstream targets of activated oncogenic pathways, or target protein coding genes involved in cancer. Moveover, miRNA-mediated therapy may be a powerful tool for cancer prevention and therapy.

Tumour characteristics predictive of survival following resection for ductal adenocarcinoma of the head of pancreas

AIMS

We have maintained a highly conservative policy in selecting patients with carcinoma of the head of pancreas for resection. This has been based on tumour size, evidence of lymph node involvement or local invasion outside of the gland at laparotomy, laparoscopy or CT imaging. This study investigated our survival rates following pancreatic resection and examined clinicopathological predictors of survival.

METHODS

Sixty-two consecutive patients undergoing pancreatic resections for malignancy were identified from 1999 onwards. Thirty-three underwent resection for pancreatic ductal adenocarcinoma and were included in our analysis, the remainder included resections for ampullary adenocarcinoma (n=20) or other malignancies (n=9). Patient, tumour and operative characteristics were analysed to assess predictors of survival following resection (Kaplan-Meier survival curves).

RESULTS

Median survival following resection for ductal pancreatic adenocarcinoma was 54 months (ampullary adenocarcinomas achieved a median survival of 62 months) and thirty-day mortality was 2.7% (n=1). Survival was not associated with any demographic or intraoperative factors, such as blood loss, operative duration or anaesthetic technique. Survival curves were significantly worse when perineural or vascular invasion was evident histologically (p=0.023 and 0.0023 respectively). Patients with positive lymph nodes had a significantly shorter survival (p=0.0030) especially when lymph node status was expressed as a percentage of total lymph node yield. If more than 20% of retrieved lymph nodes were positive for tumour, this was a clear predictor of survival (p<0.0001). A positive resection margin was also associated with shortened survival (p=0.0291).

CONCLUSION

Despite the advances made in the management of pancreatic cancer, tumour biology still dictates long-term survival. A highly selective surgical approach to the management of these patients results in good long-term survival.

Multiplexed protein detection by proximity ligation for cancer biomarker validation

We present a proximity ligation-based multiplexed protein detection procedure in which several selected proteins can be detected via unique nucleic-acid identifiers and subsequently quantified by real-time PCR. The assay requires a 1-microl sample, has low-femtomolar sensitivity as well as five-log linear range and allows for modular multiplexing without cross-reactivity. The procedure can use a single polyclonal antibody batch for each target protein, simplifying affinity-reagent creation for new biomarker candidates.

Pancreatic cancer: pathogenesis, prevention and treatment

Pancreatic cancer is the fourth leading cause of cancer death in the United States with a very low survival rate of 5 years. To better design new preventive and/or therapeutic strategies for the fight against pancreatic cancer, the knowledge of the pathogenesis of pancreatic cancer at the molecular level is very important. It has been known that the development and the progression of pancreatic cancer are caused by the activation of oncogenes, the inactivation of tumor suppressor genes, and the deregulation of many signaling pathways among which the EGFR, Akt, and NF-kappaB pathways appear to be most relevant. Therefore, the strategies targeting EGFR, Akt, NF-kappaB, and their downstream signaling could be promising for the prevention and/or treatment of pancreatic cancer. In this brief review, we will summarize the current knowledge regarding the pathogenesis, prevention, and treatment of pancreatic cancer.

The ratio of metastatic/resected lymph nodes is an independent prognostic factor in patients with node-positive pancreatic head cancer

OBJECTIVES

The aim of this study was to evaluate the prognostic value of nodal involvement in resected adenocarcinoma of the pancreatic head.

METHODS

For the period between 1980 and 2002, 96 patients underwent pancreaticoduodenectomy for pancreatic cancer. Lymph nodes were numbered and classified into groups according to the Japan Pancreatic Society rules. Metastatic lymph nodes were identified based on hematoxylin and eosin staining.

RESULTS

Sixty-four (66.7%) patients had positive lymph nodes. The median number of metastatic nodes was 2 (95% confidence interval [CI], 1.0-3.0) and the median ratio of metastatic/resected nodes was 9.7% (95% CI, 7.1%-14.4%). The median survival was 14.2 months (95% CI, 10.7-17.7) and was significantly higher for node-negative than node-positive patients (27.9; 95% CI, 20.9-34.9 vs. 10.6; 95% CI, 8.7-12.5; P < 0.001). The Cox proportional hazards model, including all patients, demonstrated that nodal involvement (hazard ratio [HR], 1.461; 95% CI, 1.177-12.024), moderate or poor tumor differentiation (HR, 2.330; 95% CI, 1.181-6.949), and positive resection margins (HR, 3.838; 95% CI, 1.390-10.597) were independent negative prognostic factors. If the analysis was limited to node-positive patients, lymph node ratio of more than 20% (HR, 1.364; 95% CI, 1.116-2.599), moderate or poor tumor differentiation (HR, 3.393; 95% CI, 1.041-11.061), and positive resection margins (HR, 9.400; 95% CI, 2.235-39.536) significantly correlated with a poorer survival.

CONCLUSIONS

Lymph node ratio seems to be a new promising prognostic factor in patients with respectable node-positive pancreatic head cancer.

Epidermal growth factor receptor-related protein inhibits cell growth and invasion in pancreatic cancer

The epidermal growth factor receptor (EGFR) signaling network plays critical roles in human cancers, including pancreatic cancer, suggesting that the discovery of specific agents targeting EGFR would be extremely valuable for pancreatic cancer therapy. EGFR-related protein (ERRP), a recently identified pan-erbB inhibitor, has been shown to inhibit growth and induce apoptosis of pancreatic cancer cells in vitro and tumor growth in a xenograft model. However, the precise molecular mechanism(s) by which ERRP exerts its antitumor activity remains unclear. The current investigation was undertaken to delineate the tumor growth inhibitory mechanism(s) of ERRP in pancreatic cancer cells. Using multiple molecular assays, such as 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, apoptosis, gene transfection, real-time reverse transcription-PCR, Western blotting, invasion, and electrophoretic mobility shift assay for measuring DNA-binding activity of nuclear factor-kappaB (NF-kappaB), we found that ERRP caused marked inhibition of pancreatic cancer cell growth. This was accompanied by increased apoptosis and concomitant attenuation of Notch-1 and NF-kappaB and down-regulation of NF-kappaB downstream genes, such as matrix metalloproteinase-9 and vascular endothelial growth factor, resulting in the inhibition of pancreatic cancer cell invasion through the Matrigel. We also found that down-regulation of Notch-1 by small interfering RNA before ERRP treatment resulted in enhanced cell growth inhibition and apoptosis. Our data suggest that the ERRP-mediated inactivation of EGFR, Notch-1, NF-kappaB, and its downstream target genes contributed to the inhibition of cell growth and invasion. We conclude that ERRP could be an effective agent for inhibiting tumor growth and invasion for the treatment of pancreatic cancer.

Sanguinarine induces apoptosis of human pancreatic carcinoma AsPC-1 and BxPC-3 cells via modulations in Bcl-2 family proteins

Pancreatic cancer is associated with low responsiveness to conventional chemotherapies and its incidence nearly equals its death rate. This warrants the development of novel mechanism-based approaches for the management of pancreatic cancer. This study was designed to determine the potential of sanguinarine, a plant alkaloid known to possess strong antimicrobial, anti-inflammatory, and antioxidant activities, against human pancreatic carcinoma cells. Employing human pancreatic carcinoma AsPC-1 and BxPC-3 cells, we specifically evaluated the pro-apoptotic and cell cycle deregulatory effects of sanguinarine and evaluated the involvement of Bcl-2 family proteins and p53 as the mechanism of the biological effects of sanguinarine. Our data demonstrated that sanguinarine (at low concentrations of 0.1-10 microM; for 24 h) treatment to AsPC-1 and BxPC-3 cells resulted in a dose dependent (i) inhibition of viability and growth, (ii) colony formation ability, (iii) induction of apoptosis, and (iv) G0-G1 phase cell cycle arrest. Further, sanguinarine-treatment to AsPC-1 and BxPC-3 cells resulted in a dose dependent (i) increase in pro-apoptotic Bax, Bid and Bak proteins; (ii) decrease in anti-apoptotic Bcl-2 and Bcl-X(L) proteins; and (iii) decrease in p53 with an increase in its phosphorylation. Based on our study, we suggest that sanguinarine may be developed as an agent for the management of pancreatic cancer. Indeed, more in depth studies both in vitro as well as in vivo in appropriate relevant animal models are needed to strengthen this suggestion.

Molecular biology of exocrine pancreatic cancer

Exocrine pancreatic cancer is one of the neoplasias with a worse prognosis, with conventional treatments having little impact on disease outcome. Research and genomic high-throughput technology is continuously expanding our knowledge of pancreas cancer biology. Characterization of genetic and epigenetic alterations in pancreatic tumors has allowed a better understanding of the progression model of the disease at the molecular level. The development of new therapeutic approaches with target- oriented agents is been tested in the preclinical and clinical settings. This review updates the current available data on pancreatic cancer molecular biology.

Matrix metalloproteinases and tumor metastasis

Functions of individual matrix metalloproteinases (MMPs) differentially expressed by tumor cells and stromal cells, are finely regulated by their spatial as well as temporal interactions with distinct cellular and extracellular components of the tumor microenvironment and also distant pre-metastatic sites. Certain aspects of MMP involvement in tumor metastasis such as tumor-induced angiogenesis, tumor invasion, and establishment of metastatic foci at the secondary site, have received extensive attention that resulted in an overwhelming amount of experimental and observational data in favor of critical roles of MMPs in these processes. In particular, dependency of tumor angiogenesis on the activity of MMPs, especially that of MMP-9, renders this step possibly the most effective target of synthetic MMP inhibitors. MMP functioning in other stages of metastasis, including the escape of individual tumor cells from the primary tumor, their intravasation, survival in circulation, and extravasation at the secondary site, have not yet received enough consideration, resulting in insufficient or controversial data. The major pieces of evidence that are most compelling and clearly determine the role and involvement of MMPs in the metastatic cascade are provided by molecular genetic studies employing knock-out or transgenic animals and tumor cell lines, modified to overexpress or downregulate a specific MMP. Findings from all of these studies implicate different functional mechanisms for both tumor and stromal MMPs during distinct steps of the metastatic cascade and indicate that MMPs can exhibit pro-metastatic as well as anti-metastatic roles depending on their nature and the experimental setting. This dual function of individual MMPs in metastasis has become a major focus of this review.

External Qi of Yan Xin Qigong differentially regulates the Akt and extracellular signal-regulated kinase pathways and is cytotoxic to cancer cells but not to normal cells

Long-term clinical observations and ongoing studies have shown significant antitumor effect of external Qi of Yan Xin Qigong which originated from traditional Chinese medicine. In order to understand the molecular and cellular mechanisms underlying the antitumor effect of external Qi of Yan Xin Qigong, we have examined its cytotoxic effect on BxPC3 pancreatic cancer cells and its effect on the Akt and extracellular signal-regulated kinase pathways. We found that external Qi of Yan Xin Qigong dramatically inhibited basal phosphorylation levels of Akt and extracellular signal-regulated kinases, epidermal growth factor-mediated phosphorylation of extracellular signal-regulated kinases, and phosphatidylinositol 3-kinase activity. External Qi of Yan Xin Qigong also inhibited constitutive and inducible activities of nuclear factor-kappa B, a target of the Akt and epidermal growth factor receptor pathways. Furthermore, a single 5min exposure of BxPC3 cells to external Qi of Yan Xin Qigong induced apoptosis, accompanied by a dramatic increase of the sub-G1 cell population, DNA fragmentation, and cleavage of caspases 3, 8 and 9, and poly(ADP-ribose) polymerase. Prolonged treatment with external Qi of Yan Xin Qigong caused rapid lysis of BxPC3 cells. In contrast, treatment of fibroblasts with external Qi of Yan Xin Qigong induced transient activation of extracellular signal-regulated kinases and Akt, and caused no cytotoxic effect. These findings suggest that external Qi of Yan Xin Qigong may differentially regulate these survival pathways in cancer versus normal cells and exert cytotoxic effects preferentially on cancer cells, and that it could potentially be a valuable approach for therapy of pancreatic carcinomas.

Neoadjuvant chemoradiation in patients with pancreatic adenocarcinoma

In spite of the high mortality in pancreatic cancer, significant progress is being made. This review discusses multimodality therapy for patients with pancreatic cancer. Surgical therapy currently offers the only potential monomodal cure for pancreatic adenocarcinoma. However, only 10-20% of patients present with tumors that are amenable to resection, and even after resection of localized cancers, long-term survival is rare. The addition of chemoradiation therapy significantly increases median survival. To achieve long-term success in treating this disease it is therefore increasingly important to identify effective neoadjuvant/adjuvant multimodality therapies. Preoperative chemoradiation for potentially resectable pancreatic cancer has the following advantages: (1) neoadjuvant treatment would eliminate the delay of adjuvant treatment due to postoperative complications; (2) neoadjuvant treatment could avoid unnecessary surgery for patients with metastatic disease evident on restaging after neoadjuvant therapy; (3) down-staging after neoadjuvant therapy may increase the likelihood of negative surgical margins; and (4) neoadjuvant treatment could prevent peritoneal tumor cell implantation and dissemination caused during surgery. This review systematically summarizes the current status, controversies, and prospects of neoadjuvant treatment of pancreatic cancer.

Tailoring Ras-pathway--inhibitor combinations for cancer therapy

Constitutive activation of Ras pathways plays a critical role in cancer development and maintenance. Inhibitors of such pathways are already in use for cancer therapy, with significant but as yet only partial success in the most deadly types of human cancers, against which even combinations of Ras-pathway inhibitors with classic cytotoxic drugs or irradiation are insufficient. Combinations of farnesyl transferase inhibitors (FTI's), inhibitors of Ras pathways, are now in use in clinical trials. In this review we analyze possible reasons for the limited efficacy--including the diverse and sometimes even contradictory effects of active Ras pathways in tumor cells--and propose possible alternative methods of tailoring Ras-pathway inhibitor combinations for cancer therapy. Such tailoring is now possible thanks to increased knowledge of the complexity of Ras pathways, their cooperation with other oncogenic pathways, and their "addictive" nature. We provide examples demonstrating that this knowledge can be translated into useful drug combinations that disrupt multiple oncogenic pathways and hit a weak point of a given tumor cell. One such example is combination treatment with a Ras inhibitor and a glycolysis blocker for pancreatic tumor cells. The future design of such potential drug combination therapies and the follow-up of their outcome will undoubtedly be facilitated by gene-expression profiling and proteomic methods.