Special Issue "Pancreatic Cancer"
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A special issue of Cancers (ISSN 2072-6694).
Deadline for manuscript submissions: closed (30 November 2010)
Special Issue Editor
Special Issue Information
Dear Colleagues,
Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies in industrialized countries. It is characterized by early metastasis and aggressive, infiltrative growth along the endothelium basement membrane and neurons. However, in recent years the crucial genetic changes leading to pancreatic cancer have been indentified. Genetic analyses of patient samples have shown that the vast majority of those cancers display mutations in KRAS and the p16 locus. Despite these advancements PDAC shows an overall five-year survival rate of only 5%. Therefore new efforts have to be made in the field of translational oncology to improve the understanding, the diagnosis and the therapy of this disease.Apart from PDAC there are other pancreatic cancer types, which differ highly in patient outcome due to their tissue origin and genetic make up. Cancers like intraductal papillary mucinous neoplasia are of growing concern to the physicians and researchers in the field. This issue will focus on the recent key findings in the field of pancreatic cancer research and therapy. It will contain different articles regarding the different types of pancreatic cancer, the latest research and new strategies to improve the therapy of this disease.
Dr. Christian Pilarsky
Guest Editor
Submission
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Keywords
- pancreas
- cancer
- tumor suppressor gene
- oncogene
- KRAs
- p53
- SMAD
- gene function
- ultrasound
- adjuvant
- neoadjuvant therapy
- epithelial mesenchymal transition
- stem cells
- apoptosis
- zeb1
- chemoresistance
- survival prediction
Published Papers (43 papers)
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Received: 24 March 2010; in revised form: 21 May 2010 / Accepted: 24 May 2010 / Published: 2 June 2010
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Abstract: The low prevalence of pancreatic cancer remains an obstacle to the development of effective screening tools in an asymptomatic population. However, development of effective serologic markers still offers the potential for improvement of diagnostic capabilities, especially for subpopulations of patients with high risk for pancreatic cancer. The accurate identification of patients with pancreatic cancer and the exclusion of disease in those with benign disorders remain important goals. While clinical experience largely dismissed many candidate markers as useful markers of pancreatic cancer, CA19-9 continues to show promise. The present review highlights the development and the properties of different tumor markers in pancreatic cancer and their impact on the diagnostic and treatment of this aggressive disease.
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Received: 26 May 2010; in revised form: 28 June 2010 / Accepted: 8 July 2010 / Published: 14 July 2010
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Abstract: Pancreatic ductal adenocarcinomas are strongly resistant to chemotherapeutic drugs and radiation, underscoring the need for new therapeutic targets, particularly ones which target the numerous out of cycle cancer cells. Analysis of resected tumors for nuclear Ki67 antigen has shown that about 70% of pancreatic cancer cells are out of cycle, some post-mitotic. Other out of cycle cells are in a quiescent, reversible G0 state, resistant to drugs which target dividing cells, with some able to repopulate a tumor. The serine/threonine kinase Mirk/dyrk1B is a downstream effector of oncogenic K-ras, the most common mutation in this cancer. Mirk expression is elevated in quiescent pancreatic cancer cells and mediates their prolonged survival through increasing expression of a cohort of antioxidant genes. Mirk is expressed in about 90% of pancreatic cancers and is amplified in a subset. Mirk appears not to be an essential gene for normal cells from embryonic knockout studies in mice and RNA interference studies on cultured cells, but is upregulated in pancreatic tumor cells. These unusual characteristics suggest that Mirk may be a selective target for therapeutic intervention.
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Received: 2 June 2010; in revised form: 30 June 2010 / Accepted: 7 July 2010 / Published: 14 July 2010
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Abstract: In the past 15 years, invasion of nerves by cancer cells has escaped from its role as a mere bystander in cancer biology and turned into an attractive niche to study the heterotypic interaction between cancer cells and neurons. Today, neural invasion (NI) in pancreatic cancer (PCa) stands out due to the recent demonstration of its association with tumor progression, local recurrence and neuropathic pain. Accordingly, recent research on NI in PCa revealed the critical involvement of numerous nerve- or cancer cell-derived molecules in several novel in vitro and in vivo models of NI, which, however, still need further major improvement.
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Received: 28 July 2010; in revised form: 5 August 2010 / Accepted: 6 August 2010 / Published: 9 August 2010
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Abstract: Survival in patients with unresectable pancreatic carcinoma is poor. Studies by Mayo Clinic and the Gastrointestinal Tumor Study Group (GITSG) have established combined modality treatment with chemotherapy and radiation as the standard of care. Use of gemcitabine-based chemotherapy alone has also been shown to provide a benefit, but 5‑year overall survival still remains less than 5%. Conventional radiotherapy is traditionally delivered over a six week period and high toxicity is seen with the concomitant use of chemotherapy. In contrast, SBRT can be delivered in 3–5 days and, when used as a component of combined modality therapy with gemcitabine, disruption to the timely delivery of chemotherapy is minimal. Early single-institution reports of SBRT for unresectable pancreatic carcinoma demonstrate excellent local control with acceptable toxicity. Use of SBRT in unresectable pancreatic carcinoma warrants further investigation in order to improve the survival of patients with historically poor outcomes.
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Received: 30 June 2010; in revised form: 16 August 2010 / Accepted: 17 August 2010 / Published: 18 August 2010
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Abstract: Pancreatic cancer is one of the most malignant human neoplasias. On the molecular level, epithelial-mesenchymal transition (EMT) has been demonstrated to contribute to the malignant phenotype of pancreatic cancer cells. ZEB1 is a transcriptional repressor that has been identified as an inducer of EMT. A negative feedback loop between ZEB1 and microRNA-200c has been shown to regulate this EMT induction in various models. With respect to pancreatic cancer, primary effects of EMT comprise increased local and distant tumor cell dissemination. Another recently described feature of the EMT is the acquisition of cancer stem cell traits. For pancreatic cancer cells, antagonism between ZEB1 and stemness-inhibiting micro-RNAs has been demonstrated to contribute to this process, providing experimental support for the migrating cancer stem cell (MCSC) hypothesis. ZEB1 has also been shown to be associated with drug resistance of pancreatic cancer cells. This article reviews the biological functions of ZEB1 with a focus on pancreatic cancer.
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Received: 2 July 2010; in revised form: 29 July 2010 / Accepted: 18 August 2010 / Published: 19 August 2010
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Abstract: Pancreatic cancer is an aggressive malignant solid tumor well-known by early metastasis, local invasion, resistance to standard chemo- and radiotherapy and poor prognosis. Increasing evidence indicates that pancreatic cancer is initiated and propagated by cancer stem cells (CSCs). Here we review the current research results regarding CSCs in pancreatic cancer and discuss the different markers identifying pancreatic CSCs. This review will focus on metastasis, microRNA regulation and anti-CSC therapy in pancreatic cancer.
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Received: 28 July 2010; in revised form: 2 September 2010 / Accepted: 2 September 2010 / Published: 9 September 2010
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Abstract: Pancreatic cancer is characterized by its late detection, aggressive growth, intense infiltration into adjacent tissue, early metastasis, resistance to chemo- and radiotherapy and a strong “desmoplastic reaction”. The dense stroma surrounding carcinoma cells is composed of fibroblasts, activated stellate cells (myofibroblast-like cells), various inflammatory cells, proliferating vascular structures, collagens and fibronectin. In particular the cellular components of the stroma produce the tumor microenvironment, which plays a critical role in tumor growth, invasion, spreading, metastasis, angiogenesis, inhibition of anoikis, and chemoresistance. Fibroblasts, myofibroblasts and activated stellate cells produce the extracellular matrix components and are thought to interact actively with tumor cells, thereby promoting cancer progression. In this review, we discuss our current understanding of the role of pancreatic stellate cells (PSC) in the desmoplastic response of pancreas cancer and the effects of PSC on tumor progression, metastasis and drug resistance. Finally we present some novel ideas for tumor therapy by interfering with the cancer cell-host interaction.
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Received: 10 September 2010; in revised form: 8 October 2010 / Accepted: 11 October 2010 / Published: 13 October 2010
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Abstract: Pancreatic ductal adenocarcinoma (PDA) is one of the most lethal human malignancy with dismal prognosis and few effective therapeutic options. Novel agents that are safe and effective are urgently needed. Oleanolic acid-derived synthetic triterpenoids are potent antitumorigenic agents, but their efficacy or the mechanism of action for pancreatic cancer has not been adequately investigated. In this study, we evaluated the antitumor activity and the mechanism of action of methyl-2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oate (CDDO-Me), a oleanane-derived synthetic triterpenoid for human pancreatic cancer cell lines. CDDO-Me inhibited the growth of both K-ras mutated (MiaPaca2, Panc1 and Capan2) and wild-type K-ras (BxPC3) pancreatic cancer cells at very low concentrations. The growth inhibitory activity of CDDO-Me was attributed to the induction of apoptosis characterized by increased annexin-V-FITC binding and cleavage of PARP-1 and procaspases-3, -8 and-9. In addition, CDDO-Me induced the loss of mitochondrial membrane potential and release of cytochrome C. The antitumor activity of CDDO-Me was associated with the inhibition of prosurvival p-Akt, NF-κB and mammalian target of rapamycin (mTOR) signaling proteins and the downstream targets of Akt and mTOR, such as p-Foxo3a (Akt) and p-S6K1, p-eIF-4E and p-4E-BP1 (mTOR). Silencing of Akt or mTOR with gene specific-siRNA sensitized the pancreatic cancer cells to CDDO-Me, demonstrating Akt and mTOR as molecular targets of CDDO-Me for its growth inhibitory and apoptosis-inducing activity.
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Received: 17 September 2010; in revised form: 14 October 2010 / Accepted: 18 October 2010 / Published: 25 October 2010
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Abstract: Pancreatic cancer is characterized by an often dramatic outcome (five year survival < 5%) related to a late diagnosis and a lack of efficient therapy. Therefore, clinicians desperately need new biomarkers and new therapeutic tools to develop new efficient therapies. Mucins belong to an ever increasing family of O-glycoproteins. Secreted mucins are the main component of mucus protecting the epithelia whereas membrane-bound mucins are thought to play important biological roles in cell-cell and cell-matrix interactions, in cell signaling and in modulating biological properties of cancer cells. In this review, we will focus on the altered expression pattern of mucins in pancreatic cancer, from the early neoplastic lesion Pancreatic Intraepithelial Neoplasia (PanIN) to invasive pancreatic carcinomas, and the molecular mechanisms (including genetic and epigenetic regulation) and signaling pathways known to control their expression. Moreover, we will discuss the recent advances about the biology of both secreted and membrane-bound mucins and their key roles in pancreatic carcinogenesis and resistance to therapy. Finally, we will discuss exciting opportunities that mucins offer as potential therapeutic targets in pancreatic cancer.
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Received: 21 October 2010 / Accepted: 29 October 2010 / Published: 2 November 2010
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Abstract: Pancreatic cancer is the fourth most common cause of cancer-related mortality in the United States. Biomarkers are needed to detect this cancer early during the disease development and for screening populations to identify those who are at risk. In cancer, “biomarker” refers to a substance or process that is indicative of the presence of cancer in the body. A biomarker might be either a molecule secreted by a tumor or it can be a specific response of the body to the presence of cancer. Genetic, epigenetic, proteomic, glycomic, and imaging biomarkers can be used for cancer diagnosis, prognosis, and epidemiology. A number of potential biomarkers have been identified for pancreatic cancer. These markers can be assayed in non-invasively collected biofluids. These biomarkers need analytical and clinical validation so that they can be used for the purpose of screening and diagnosing pancreatic cancer and determining disease prognosis. In this article, the latest developments in pancreatic cancer biomarkers are discussed.
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Received: 12 October 2010; in revised form: 3 November 2010 / Accepted: 4 November 2010 / Published: 10 November 2010
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Abstract: Pancreatic cancer’s high mortality rate equates closely with its incidence, thereby showing the need for development of biomarkers of its increased risk and a better understanding of its genetics, so that high-risk patients can be better targeted for screening and early potential lifesaving diagnosis. Its phenotypic and genotypic heterogeneity is extensive and requires careful scrutiny of its pattern of cancer associations, such as malignant melanoma associated with pancreatic cancer, in the familial atypical multiple mole melanoma syndrome, due to the CDKN2A germline mutation. This review is designed to depict several of the hereditary pancreatic cancer syndromes with particular attention given to the clinical application of this knowledge into improved control of pancreatic cancer.
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Received: 19 October 2010; in revised form: 8 November 2010 / Accepted: 16 November 2010 / Published: 18 November 2010
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Abstract: Pancreatic neuroendocrine tumors (PNETs) are rare primary neoplasms of the pancreas and arise sporadically or in the context of genetically determined syndromes. Depending on hormone production and sensing, PNETs clinically manifest due to a hormone-related syndrome (functional PNET) or by symptoms related to tumor bulk effects (non-functional PNET). So far, radical surgical excision is the only therapy to cure the disease. Development of tailored non-surgical approaches has been impeded by the lack of experimental laboratory models and there is, therefore, a limited understanding of the complex cellular and molecular biology of this heterogeneous group of neoplasm. This review aims to summarize current knowledge of tumorigenesis of familial and sporadic PNETs on a cellular and molecular level. Open questions in the field of PNET research are discussed with specific emphasis on the relevance of disease management.
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Received: 12 October 2010; in revised form: 11 November 2010 / Accepted: 22 November 2010 / Published: 24 November 2010
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Abstract: Pancreatic cancer has the worst prognosis of all gastrointestinal neoplasms. Five-year survival of pancreatic cancer after pancreatectomy is very low, and surgical resection is the only option to cure this dismal disease. The standard surgical procedure is pancreatoduodenectomy (PD) for pancreatic head cancer. The morbidity and especially the mortality of PD have been greatly reduced. Portal vein resection in pancreatic cancer surgery is one attempt to increase resectability and radicality, and the procedure has become safe to perform. Clinicohistopathological studies have shown that the most important indication for portal vein resection in patients with pancreatic cancer is the ability to obtain cancer-free surgical margins. Otherwise, portal vein resection is contraindicated.
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Received: 30 October 2010 / Accepted: 17 November 2010 / Published: 25 November 2010
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Abstract: To date, curative resection is the only chance for cure for patients suffering from pancreatic ductal adenoacarcinoma (PDAC). Despite low reported rates of microscopic tumor infiltration (R1) in most studies, tumor recurrence is a common finding in patients with PDAC and contributes to extremely low long-term survival rates. Lack of international definition of resection margins and of standardized protocols for pathological examination lead to high variation in reported R1 rates. Here we review recent studies supporting the hypothesis that R1 rates are highly underestimated in certain studies and that a microscopic tumor clearance of at least 1 mm is required to confirm radicality and to serve as a reliable prognostic and predictive factor.
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Received: 18 October 2010; in revised form: 9 November 2010 / Accepted: 22 November 2010 / Published: 29 November 2010
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Abstract: Pancreatic cancer is a lethal disease and notoriously difficult to treat. Only a small proportion is curative by surgical resection, whilst standard chemotherapy for patients with advanced disease has only a modest effect with substantial toxicity. Clearly there is a need for the continual development of novel therapeutic agents to improve the current situation. Currently, there is a bulk of data indicating the important function of autophagy in cancer. While genetic evidence indicates that autophagy functions as a tumor suppressor, it is also apparent that autophagy can promote the survival of established tumors under stress conditions and in response to chemotherapy. This review provides a spectrum of potential pharmacological agents and autophagic approaches to enhance cell killing in pancreatic cancer.
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Received: 22 October 2010; in revised form: 29 November 2010 / Accepted: 30 November 2010 / Published: 2 December 2010
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Abstract: Pancreatic cancer is one of the most lethal cancers, where curative surgical resections are rare and less than 5% of patients experience long-term survival. Despite numerous clinical trials, improvements in the systemic treatment of this disease have been limited. Gemcitabine, a nucleoside analogue, is still considered the standard of care chemotherapy for most patients in the advanced disease setting. To exert its cytotoxic effects, gemcitabine must enter cells via nucleoside transporters, most notably human equilibrative nucleoside transporter 1 (hENT1). Increasingly strong evidence suggests hENT1 is a prognostic biomarker in gemcitabine-treated pancreatic cancer, and may well be a predictive biomarker of gemcitabine efficacy. In this review, we synthesize the literature surrounding hENT1 in pancreatic cancer, identify the key outstanding questions, and suggest strategies to prospectively evaluate the clinical utility of hENT1 in future clinical studies.
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Received: 9 November 2010; in revised form: 1 December 2010 / Accepted: 1 December 2010 / Published: 9 December 2010
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Abstract: Pancreatic carcinoma is the fourth-leading cause of cancer death and is characterized by early invasion and metastasis. The developmental program of epithelial-mesenchymal transition (EMT) is of potential importance for this rapid tumor progression. During EMT, tumor cells lose their epithelial characteristics and gain properties of mesenchymal cells, such as enhanced motility and invasive features. This review will discuss recent findings pertinent to EMT in pancreatic carcinoma. Evidence for and molecular characteristics of EMT in pancreatic carcinoma will be outlined, as well as the connection of EMT to related topics, e.g., cancer stem cells and drug resistance.
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Received: 24 October 2010; in revised form: 1 December 2010 / Accepted: 1 December 2010 / Published: 9 December 2010
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Abstract: Pancreatic adenocarcinoma (PDAC) is one of the most lethal human malignancies, with median survival of less than one year and overall five-year survival of less than 5%. There is increasing evidence demonstrating that epithelial-mesenchymal transition (EMT) contributes to pancreatic cancer metastasis and to treatment resistance. In this review, we will examine the data demonstrating the role and regulation of EMT in pancreatic cancer progression, focusing particularly on the transcription factors and microRNAs involved in EMT. We will examine how EMT is involved in the generation and maintenance of stem cells, and the role of EMT in modulating resistance of PDAC cells to drug therapies. We will also identify putative EMT-targeting agents that may help to reduce the morbidity and mortality associated with pancreatic cancer.
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Received: 1 November 2010; in revised form: 7 December 2010 / Accepted: 13 December 2010 / Published: 16 December 2010
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Abstract: Pancreatic ductal adenocarcinoma remains one of the most lethal of all solid tumors with an overall five-year survival rate of only 3–5%. Its aggressive biology and resistance to conventional and targeted therapeutic agents lead to a typical clinical presentation of incurable disease once diagnosed. The disease is characterized by the presence of a dense stroma of fibroblasts and inflammatory cells, termed desmoplasia, which limits the oxygen diffusion in the organ, creating a strong hypoxic environment within the tumor. In this review, we argue that hypoxia is responsible for the highly aggressive and metastatic characteristics of this tumor and drives pancreatic cancer cells to oncogenic and metabolic changes facilitating their proliferation. However, the molecular changes leading to metabolic adaptations of pancreatic cancer cells remain unclear. Cachexia is a hallmark of this disease and illustrates that this cancer is a real metabolic disease. Hence, this tumor must harbor metabolic pathways which are probably tied in a complex inter-organ dialog during the development of this cancer. Such a hypothesis would better explain how under fuel source limitation, pancreatic cancer cells are maintained, show a growth advantage, and develop metastasis.
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Received: 11 November 2010; in revised form: 14 December 2010 / Accepted: 21 December 2010 / Published: 23 December 2010
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Abstract: Pancreatic cancer is a disease with high resistance to most common therapies and therefore has a poor prognosis, which is partly due to a lack of reaction to apoptotic stimuli. Signal transduction of such stimuli includes a death receptor-mediated extrinsic pathway as well as an intrinsic pathway linked to the mitochondria. Defects in apoptotic pathways and the deregulation of apoptotic proteins, such as Survivin, Bcl-2, Bcl-xL and Mcl-1, play decisive roles in the development of pancreatic cancer. Investigation of the molecular mechanism allowing tumors to resist apoptotic cell death would lead to an improved understanding of the physiology and the development of new molecular strategies in pancreatic cancer.
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Received: 1 November 2010; in revised form: 25 November 2010 / Accepted: 20 December 2010 / Published: 24 December 2010
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Abstract: A majority of pancreatic cancer patients present with pain at the time of diagnosis. Pain management can be challenging in light of the aggressive nature of this cancer. Apart from conventional pharmacotherapy, timely treatment with neurolytic celiac plexus block (NCPB) has been shown to be of benefit. NCPB has demonstrated efficacious pain control in high quality studies with analgesic effects lasting one to two months. NCPB has also shown to decrease the requirements of narcotics, and thus decrease opioid related side effects. Another option for the control of moderate to severe pain is intrathecal therapy (IT). Delivery of analgesic medications intrathecally allows for lower dosages of medications and thus reduced toxicity. Both of the above mentioned interventional procedures have been shown to have low complication rates, and be safe and effective. Ultimately, comprehensive pancreatic cancer pain management necessitates understanding of pain mechanisms and delivery of sequential validated therapeutic interventions within a multidisciplinary patient care model.
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Received: 23 November 2010; in revised form: 21 December 2010 / Accepted: 23 December 2010 / Published: 29 December 2010
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Abstract: Pancreatic cancer exhibits an extraordinarily high level of resistance to almost any kind of systemic therapy evaluated in clinical trials so far. Therefore, the identification of novel therapeutic targets is urgently required. High-throughput screens have emerged as an important tool to identify putative targets for diagnosis and therapy in an unbiased manner. More than a decade ago, microarray technology was introduced to identify differentially expressed genes in pancreatic cancer as compared to normal pancreas, chronic pancreatitis and other cancer types located in close proximity to the pancreas. In addition, proteomic screens have facilitated the identification of differentially secreted proteins in body fluids of pancreatic cancer patients, serving as possible biomarkers. Recently, RNA interference-based loss-of-function screens have been used to identify functionally relevant genes, whose knock-down has impact on pancreatic cancer cell viability, thereby representing potential new targets for therapeutic intervention. This review summarizes recent results of transcriptional, proteomic and functional screens in pancreatic cancer and discusses potentials and limitations of the respective technologies as well as their impact on future therapeutic developments.
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Received: 1 December 2010; in revised form: 10 December 2010 / Accepted: 24 December 2010 / Published: 30 December 2010
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Abstract: Pancreatic cancer ranks among the tumors most resistant to chemotherapy. Such chemoresistance of tumors can be mediated by various cellular mechanisms including dysregulated apoptosis or ineffective drug concentration at the intracellular target sites. In this review, we highlight recent advances in experimental chemotherapy underlining the role of cellular transporters in drug resistance. Such contribution to the chemoresistant phenotype of tumor cells or tissues can be conferred both by uptake and export transporters, as demonstrated by in vivo and in vitro data. Our studies used human pancreatic carcinoma cells, cells stably transfected with human transporter cDNAs, or cells in which a specific transporter was knocked down by RNA interference. We have previously shown that 5-fluorouracil treatment affects the expression profile of relevant cellular transporters including multidrug resistance proteins (MRPs), and that MRP5 (ABCC5) influences chemoresistance of these tumor cells. Similarly, cell treatment with the nucleoside drug gemcitabine or a combination of chemotherapeutic drugs can variably influence the expression pattern and relative amount of uptake and export transporters in pancreatic carcinoma cells or select for pre-existing subpopulations. In addition, cytotoxicity studies with MRP5-overexpressing or MRP5-silenced cells demonstrate a contribution of MRP5 also to gemcitabine resistance. These data may lead to improved strategies of future chemotherapy regimens using gemcitabine and/or 5-fluorouracil.
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Received: 1 December 2010; in revised form: 24 December 2010 / Accepted: 27 December 2010 / Published: 4 January 2011
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Abstract: Pancreatic adenocarcinoma is a devastating disease characterized by early dissemination and poor prognosis. These solid tumors express receptors for neuropeptides like neurotensin (NT) or epidermal growth factor (EGF) and exhibit acidic regions when grown beyond a certain size. We previously demonstrated increases in intracellular Ca2+ levels, intracellular pH and interleukin-8 (IL-8) secretion in BxPC-3 and PANC-1 pancreatic cancer cells in response to a stable NT analog. The present study aimed at investigation of the dependence of the relative expression of NT receptor 1 (NTR1) and EGFR in BxPC-3 and MIA PaCa-2 cells on cell density and extracellular pH (pHe). MTT assays revealed the NTR1 inhibitor SR 142948-sensitive Lys8-ψ-Lys9NT (8–13)-induced proliferation in BxPC-3 and PANC-1 cells. Confluent cultures of BxPC3 and HT-29 lines exhibited highest expression of NTR1 and lowest of EGFR and expression of NTR1 was maximal at slightly acidic pHe. IL-8 production was stimulated by Lys8-ψ-Lys9NT (8–13) and even enhanced at both acidic and alkaline pHe in BxPC-3 and PANC-1 cells. In conclusion, our in vitro study suggests that one contributing factor to the minor responses obtained with EGFR-directed therapy may be downregulation of this receptor in tumor cell aggregates, possibly resulting in acquisition of a more aggressive phenotype via other growth factor receptors like NTR1.
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Received: 7 December 2010; in revised form: 30 December 2010 / Accepted: 31 December 2010 / Published: 6 January 2011
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Abstract: The non-classical actions of vitamin D, namely anti-proliferation, pro-differentiation, immune function modulation, and anti-inflammation, have received great attention during the past decade, in particular, the potential of vitamin D analogs alone or in combination with other anticancer agents for the treatment of a variety of cancers. The association between vitamin D status and the higher incidence of many forms of cancer has suggested that vitamin D may play a role in the etiology of these types of cancer. Although it is still controversial whether this association exists for pancreatic cancer, biochemical evidence clearly indicates pancreatic cancer cells are responsive to the inhibitory effect of vitamin D and its analogs. In this review, we discuss briefly the origin and current therapy of pancreatic cancer, the history, source, metabolism and functions of vitamin D, the recent progress in the epidemiological studies of sunlight, and vitamin D status, and biochemical studies of vitamin D analogs in the prevention and treatment of pancreatic cancer.
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Received: 5 November 2010; in revised form: 5 December 2010 / Accepted: 10 January 2011 / Published: 11 January 2011
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Abstract: Laboratory evidence of aberrant coagulation is found in the majority of patients with advanced pancreatic cancer and a clinical consequence of this is the high incidence and prevalence of vascular thromboembolic events. Other sequelae are hypothesized to be the facilitation and acceleration of mechanisms that define the malignant phenotype, such as invasion, trafficking and anchoring, establishing the metastatic niche and inducing angiogenesis. We review the in vitro and preclinical evidence that supports the role of the coagulation apparatus in the metastatic process of pancreatic cancer, with a particular emphasis on interaction of this pathway with clinically-targeted growth factor receptor pathways. Links between hemostasis, angiogenesis and epidermal growth factor pathways and their significance as therapeutic targets are considered.
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Received: 1 December 2010; in revised form: 5 January 2011 / Accepted: 13 January 2011 / Published: 18 January 2011
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Abstract: The continuous identification of molecular changes deregulating critical pathways in pancreatic tumor cells provides us with a large number of novel candidates to engineer gene-targeted approaches for pancreatic cancer treatment. Targets—both protein coding and non-coding—are being exploited in gene therapy to influence the deregulated pathways to facilitate cytotoxicity, enhance the immune response or sensitize to current treatments. Delivery vehicles based on viral or non-viral systems as well as cellular vectors with tumor homing characteristics are a critical part of the design of gene therapy strategies. The different behavior of tumoral versus non-tumoral cells inspires vector engineering with the generation of tumor selective products that can prevent potential toxic-associated effects. In the current review, a detailed analysis of the different targets, the delivery vectors, the preclinical approaches and a descriptive update on the conducted clinical trials are presented. Moreover, future possibilities in pancreatic cancer treatment by gene therapy strategies are discussed.
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Received: 17 December 2010; in revised form: 18 January 2011 / Accepted: 21 January 2011 / Published: 24 January 2011
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Abstract: Pancreatic cancer develops and progresses through complex, cumulative biological processes involving metabolic disorder, local inflammation, and deregulated molecular pathways. The resulting tumor aggressiveness hampers surgical intervention and renders pancreatic cancer resistant to standard chemotherapy and radiation therapy. Based on these pathologic properties, several therapeutic strategies are being developed to reverse refractory pancreatic cancer. Here, we outline molecular targeting therapies, which are primarily directed against growth factor receptor-type tyrosine kinases deregulated in tumors, but have failed to improve the survival of pancreatic cancer patients. Glycogen synthase kinase-3β (GSK3β) is a member of a serine/threonine protein kinase family that plays a critical role in various cellular pathways. GSK3β has also emerged as a mediator of pathological states, including glucose intolerance, inflammation, and various cancers (e.g., pancreatic cancer). We review recent studies that demonstrate the anti-tumor effects of GSK3β inhibition alone or in combination with chemotherapy and radiation. GSK3β inhibition may exert indirect anti-tumor actions in pancreatic cancer by modulating metabolic disorder and inflammation.
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Received: 1 December 2010; in revised form: 20 January 2011 / Accepted: 24 January 2011 / Published: 31 January 2011
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Abstract: Pancreatic cancer is one of the most deadly solid tumors, with an overall 5-year survival rate of less than 5%. Due to a non-specific clinical presentation, it is often diagnosed at an advanced stage and is rarely amenable for curative treatment. Therefore early diagnosis and appropriate staging are still essential to define the best care and to improve patient survival. Several imaging modalities are currently available for the evaluation of pancreatic cancer. This review focuses on different techniques and discusses the diagnostic management of patients with pancreatic cancer. This review was conducted utilizing Pubmed and was limited to papers published within the last 5 years. The search key words pancreatic cancer, pancreatic adenocarcinoma, pancreatic tumors, diagnosis, radiology, imaging, nuclear imaging, endoscopy, endoscopic ultrasound and biochemical markers were used.
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Received: 1 December 2010; in revised form: 29 December 2010 / Accepted: 26 January 2011 / Published: 9 February 2011
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Abstract: Pancreatic cancer is difficult to cure, so its prevention is very important. For this purpose, animal model studies are necessary to develop effective methods. Injection of N-nitrosobis(2-oxopropyl)amine (BOP) into Syrian golden hamsters is known to induce pancreatic ductal adenocarcinomas, the histology of which is similar to human tumors. Moreover, K-ras activation by point mutations and p16 inactivation by aberrant methylation of 5’ CpG islands or by homozygous deletions have been frequently observed in common in both the hamster and humans. Thus, this chemical carcinogenesis model has an advantage of histopathological and genetic similarity to human pancreatic cancer, and it is useful to study promotive and suppressive factors. Syrian golden hamsters are in a hyperlipidemic state even under normal dietary conditions, and a ligand of peroxizome proliferator-activated receptor gamma was found to improve the hyperlipidemia and suppress pancreatic carcinogenesis. Chronic inflammation is a known important risk factor, and selective inhibitors of inducible nitric oxide synthase and cyclooxygenase-2 also have protective effects against pancreatic cancer development. Anti-inflammatory and anti-hyperlipidemic agents can thus be considered candidate chemopreventive agents deserving more attention.
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Received: 20 December 2010; in revised form: 19 January 2011 / Accepted: 5 February 2011 / Published: 11 February 2011
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Abstract: Despite all improvements in both surgical and other conservative therapies, pancreatic cancer is steadily associated with a poor overall prognosis and remains a major cause of cancer mortality. Radical surgical resection has been established as the best chance these patients have for long-term survival. However, in most cases the disease has reached an incurable state at the time of diagnosis, mainly due to the silent clinical course at its early stages. The role of palliative surgery in locally advanced pancreatic cancer mainly involves patients who are found unresectable during open surgical exploration and consists of combined biliary and duodenal bypass procedures. Chemical splanchnicectomy is another modality that should also be applied intraoperatively with good results. There are no randomized controlled trials evaluating the outcomes of palliative pancreatic resection. Nevertheless, data from retrospective reports suggest that this practice, compared with bypass procedures, may lead to improved survival without increasing perioperative morbidity and mortality. All efforts at developing a more effective treatment for unresectable pancreatic cancer have been directed towards neoadjuvant and targeted therapies. The scenario of downstaging tumors in anticipation of a future oncological surgical resection has been advocated by trials combining gemcitabine with radiation therapy or with the tyrosine kinase inhibitor erlotinib, with promising early results.
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Received: 31 December 2010; in revised form: 14 January 2011 / Accepted: 9 February 2011 / Published: 14 February 2011
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Abstract: Palliative treatment concepts are considered in patients with non-curatively resectable and/or metastasized pancreatic cancer. However, patients without metastases, but presented with marginally resectable or locally non-resectable tumors should not be treated by a palliative therapeutic approach. These patients should be enrolled in neoadjuvant radiochemotherapy trials because a potentially curative resection can be achieved in approximately one-third of them after finishing treatment and restaging. Within the scope of best possible palliative care, resection of the primary cancer together with excision of metastases represents a therapeutic option to be contemplated in selected cases. Comprehensive palliative therapy is based on treatment of bile duct or duodenal obstruction for certain locally unresectable or metastasized advanced pancreatic cancer. However, endoscopic or percutaneous stenting procedures and surgical bypass provide safe and highly effective therapeutic alternatives. In case of operative drainage of the biliary tract (biliodigestive anastomosis), the prophylactic creation of a gastro-intestinal bypass (double bypass) is recommended. The decision to perform a surgical versus an endoscopic procedure for palliation depends to a great extent on the tumor stage and the estimated prognosis, and should be determined by an interdisciplinary team for each patient individually.
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Received: 3 December 2010; in revised form: 24 January 2011 / Accepted: 4 February 2011 / Published: 17 February 2011
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Abstract: Managing pancreatic cancer remains a big challenge due to its worse course and prognosis. However, therapeutic options and multimodal strategies are increasing nowadays, including new agents, new regimens and chemoradiation. Recently, the FOLFIRINOX regimen has been reported to be more active than gemcitabine in selected metastatic patients. In this setting, it will be of utmost interest to guide our therapeutic choice not only on clinical and pathological findings, but also on specific biomarkers that will predict tumor behavior and patient outcome (prognostic markers), and benefit from specific agents or regimens (predictive markers). In the near future, we will have to build both our therapeutic interventions and our clinical research based on an accurate patients’ clinical selection and on biomolecular markers. In this review, we aimed to highlight and discuss some of the recent results reported on biomarkers in pancreatic cancer that may predict, i.e., preferential metastatic diffusion after surgery, like CXCR4, or predict gemcitabine efficacy in an adjuvant setting as well as in advanced disease, like hENT1. An important effort for translational research in pancreatic cancer research is thus required to validate such markers, while some important questions concerning tissue availability and processing, methodology of analysis, and design of future prospective trials, need to be addressed.
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Received: 26 January 2011; in revised form: 12 February 2011 / Accepted: 16 February 2011 / Published: 24 February 2011
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Abstract: Functionally, the pancreas consists of two types of tissues: exocrine and endocrine. Exocrine pancreatic disorders mainly involve acute and chronic pancreatitis. Acute pancreatitis typically is benign, while chronic pancreatitis is considered a risk factor for developing pancreatic cancer. Pancreatic carcinoma is the fourth leading cause of cancer related deaths worldwide. Most pancreatic cancers develop in the exocrine tissues. Endocrine pancreatic tumors are more uncommon, and typically are less aggressive than exocrine tumors. However, the endocrine pancreatic disorder, diabetes, is a dominant cause of morbidity and mortality. Importantly, different growth factors and their receptors play critical roles in pancreatic pathogenesis. Hence, an improved understanding of how various growth factors affect pancreatitis and pancreatic carcinoma is necessary to determine appropriate treatment. This chapter describes the role of different growth factors such as vascular endothelial growth factor (VEGF), insulin-like growth factor (IGF), platelet derived growth factor (PDGF), fibroblast growth factor (FGF), epidermal growth factor (EGF), and transforming growth factor (TGF) in various pancreatic pathophysiologies. Finally, the crosstalk between different growth factor axes and their respective signaling mechanisms, which are involved in pancreatitis and pancreatic carcinoma, are also discussed.
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Received: 18 January 2011; in revised form: 5 February 2011 / Accepted: 22 February 2011 / Published: 24 February 2011
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Abstract: Endoscopic ultrasound-guided fine needle aspiration-biopsy is a safe and effective technique in diagnosing and staging of pancreatic ductal adenocarcinoma. However its predictive negative value does not exceed 50% to 60%. Unfortunately, the majority of pancreatic cancer patients have a metastatic and/or a locally advanced disease (i.e., not eligible for curative resection) which explains the limited access to pancreatic tissue specimens. Endoscopic ultrasound-guided fine needle aspiration-biopsy is the most widely used approach for cytological and histological material sampling in these situations used in up to two thirds of patients with pancreatic cancer. Based on this unique material, we and others developed strategies to improve the differential diagnosis between carcinoma and inflammatory pancreatic lesions by analysis of KRAS oncogene mutation, microRNA expression and methylation, as well as mRNA expression using both qRT-PCR and Low Density Array Taqman analysis. Indeed, differentiating pancreatic cancer from pseudotumoral chronic pancreatitis remains very difficult in current clinical practice, and endoscopic ultrasound-guided fine needle aspiration-biopsy analysis proved to be very helpful. In this review, we will compile the clinical and molecular advantages of using endoscopic ultrasound-guided fine needle aspiration-biopsy in managing pancreatic cancer.
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Received: 13 January 2011; in revised form: 1 February 2011 / Accepted: 14 February 2011 / Published: 25 February 2011
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Abstract: Pancreatic cancer (PC) is among the deadliest cancers, with a median survival of six months. It is generally believed that infiltrating PC arises through the progression of early grade pancreatic intraepithelial lesions (PanINs). In one model of the disease, the K-ras mutation is an early molecular event during progression of pancreatic cancer; it is followed by the accumulation of additional genetic abnormalities. This model has been supported by animal studies in which activated K-ras and p53 mutations produced metastatic pancreatic ductal adenocarcinoma in mice. According to this model, oncogenic K-ras induces PanIN formation but fails to promote the invasive stage. However, when these mice are subjected to caerulein treatment, which induces a chronic pancreatitis-like state and inflammatory response, PanINs rapidly progress to invasive carcinoma. These results are consistent with epidemiologic studies showing that patients with chronic pancreatitis have a much higher risk of developing PC. In line with these observations, recent studies have revealed elevated expression of the pro-inflammatory protein tissue transglutaminase (TG2) in early PanINs, and its expression increases even more as the disease progresses. In this review we discuss the implications of increased TG2 expression in initiation, progression, and pathogenesis of pancreatic cancer.
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Received: 10 February 2011; in revised form: 19 February 2011 / Accepted: 10 March 2011 / Published: 10 March 2011
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Abstract: Pancreatic cancer is still associated with a poor prognosis and remains—as the fourth leading cause of cancer related mortality—a therapeutic challenge. Overall long-term survival is about 1–5%, and in only 10–20% of pancreatic cancer patients is potentially curative surgery possible, increasing five-year survival rates to approximately 20–25%. Pancreatic surgery is a technically challenging procedure and has significantly changed during the past decades with regard to technical aspects as well as perioperative care. Standardized resections can be carried out with low morbidity and mortality below 5% in high volume institutions. Furthermore, there is growing evidence that also more extended resections including multivisceral approaches, vessel reconstructions or surgery for tumor recurrence can be carried out safely with favorable outcomes. The impact of adjuvant treatment, especially chemotherapy, has increased dramatically within recent years, leading to significantly improved postoperative survival, making pancreatic cancer therapy an interdisciplinary approach to achieve best results.
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Received: 5 February 2011; in revised form: 28 February 2011 / Accepted: 11 March 2011 / Published: 24 March 2011
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Abstract: Pancreatic cancer is the fourth leading cause of cancer related death. The difficulty in detecting pancreatic cancer at an early stage, aggressiveness and the lack of effective therapy all contribute to the high mortality. Epidermal growth factor receptor (EGFR) is a transmembrane glycoprotein, which is expressed in normal human tissues. It is a member of the tyrosine kinase family of growth factors receptors and is encoded by proto-oncogenes. Several studies have demonstrated that EGFR is over-expressed in pancreatic cancer. Over-expression correlates with more advanced disease, poor survival and the presence of metastases. Therefore, inhibition of the EGFR signaling pathway is an attractive therapeutic target. Although several combinations of EGFR inhibitors with chemotherapy demonstrate inhibition of tumor-induced angiogenesis, tumor cell apoptosis and regression in xenograft models, these benefits remain to be confirmed. Multimodality treatment incorporating EGFR-inhibition is emerging as a novel strategy in the treatment of pancreatic cancer.
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Received: 18 February 2011; in revised form: 24 February 2011 / Accepted: 16 March 2011 / Published: 24 March 2011
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Abstract: Pancreatic cancer (PC) has a complex etiology and displays a wide range of cellular escape pathways that allow it to resist different treatment modalities. Crucial signaling molecules that function downstream of the survival pathways, particularly at points where several of these pathways crosstalk, provide valuable targets for the development of novel anti-cancer drugs. Bcl-2 family member proteins are anti-apoptotic molecules that are known to be overexpressed in most cancers including PC. The anti-apoptotic machinery has been linked to the observed resistance developed to chemotherapy and radiation and therefore is important from the targeted drug development point of view. Over the past ten years, our group has extensively studied a series of small molecule inhibitors of Bcl-2 against PC and provide solid preclinical platform for testing such novel drugs in the clinic. This review examines the efficacy, potency, and function of several small molecule inhibitor drugs targeted to the Bcl-2 family of proteins and their preclinical progress against PC. This article further focuses on compounds that have been studied the most and also discusses the anti-cancer potential of newer class of Bcl-2 drugs.
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Received: 21 December 2010; in revised form: 29 December 2010 / Accepted: 12 January 2011 / Published: 1 April 2011
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Abstract: Evidence for the efficacy of targeted alpha therapy for the control of pancreatic cancer in preclinical models is reviewed. Results are given for in vitro pancreatic cancer cells and clusters and micro-metastatic cancer lesions in vivo. Two complementary targeting vectors are examined. These are the C595 monoclonal antibody that targets the MUC1 antigen and the PAI2 ligand that targets the uPA receptor. The expression of the tumor-associated antigen MUC-1 and the uPA receptor on three pancreatic cancer cell lines is reported for cell clusters, human mouse xenografts and lymph node metastases, as well as for human pancreatic cancer tissues, using immuno-histochemistry, confocal microscopy and flow cytometry. The targeting vectors C595 and PAI2 were labeled with the alpha emitting radioisotope 213Bi using the chelators cDTPA and CHX-A″ to form the alpha-conjugates (AC). Cell clusters were incubated with the AC and examined at 48 hours. Apoptosis was documented using the TUNEL assay. In vivo, the anti-proliferative effect for tumors was tested at two days post-subcutaneous cell inoculation. Mice were injected with different concentrations of AC by local or systemic administration. Changes in tumor progression were assessed by tumor size. MUC-1 and uPA are strongly expressed on CFPAC-1, PANC-1 and moderate expression was found CAPAN-1 cell clusters and tumor xenografts. The ACs can target pancreatic cells and regress cell clusters (~100 µm diameter), causing apoptosis in some 70–90 % of cells. At two days post-cell inoculation in mice, a single local injection of 74 MBq/kg of AC causes complete inhibition of tumor growth. Systemic injections of 111, 222 and 333 MBq/kg of alpha-conjugate caused significant tumor growth delay in a dose dependent manner after 16 weeks, compared with the non-specific control at 333 MBq/kg. Cytotoxicity was assessed by the MTS and TUNEL assays. The C595 and PAI2-alpha conjugates are indicated for the treatment of micro-metastatic pancreatic cancer with over-expression of MUC1 and uPA receptors in post-surgical patients with minimal residual disease. The observation of tumor regression in a Phase I clinical trial of targeted alpha therapy for metastatic melanoma indicates that alpha therapy can regress tumors by a process called tumor anti-vascular alpha therapy (TAVAT). As a consequence, this therapy could be indicated for the management of non-surgical pancreatic cancer tumors.
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Received: 1 March 2011; in revised form: 1 April 2011 / Accepted: 1 April 2011 / Published: 13 April 2011
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Abstract: Pancreatic cancer is devastating due to its poor prognosis. Patients require a multidisciplinary approach to guide available options, mostly palliative because of advanced disease at presentation. Palliation including relief of biliary obstruction, gastric outlet obstruction, and cancer-related pain has become the focus in patients whose cancer is determined to be unresectable. Endoscopic stenting for biliary obstruction is an option for drainage to avoid the complications including jaundice, pruritus, infection, liver dysfunction and eventually failure. Enteral stents can relieve gastric obstruction and allow patients to resume oral intake. Pain is difficult to treat in cancer patients and endoscopic procedures such as pancreatic stenting and celiac plexus neurolysis can provide relief. The objective of endoscopic palliation is to primarily address symptoms as well improve quality of life.
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Received: 17 March 2011; in revised form: 9 April 2011 / Accepted: 26 April 2011 / Published: 9 May 2011
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Abstract: Pancreatic cancer is a devastating disease. It is the fourth leading cause of cancer-related death in Germany. The incidence in 2003/2004 was 16 cases per 100.000 inhabitants. Of all carcinomas, pancreatic cancer has the highest mortality rate, with one- and five-year survival rates of 25% and less than 5%, respectively, regardless of the stage at diagnosis. These low survival rates demonstrate the poor prognosis of this carcinoma. Previous therapeutic approaches including surgical resection combined with adjuvant therapy or palliative chemoradiation have not achieved satisfactory results with respect to overall survival. Therefore, it is necessary to evaluate new therapeutic approaches. Neoadjuvant therapy is an interesting therapeutic option for patients with pancreatic cancer. For selected patients with borderline or unresectable disease, neoadjuvant therapy offers the potential for tumor downstaging, increasing the probability of a margin-negative resection and decreasing the occurrence of lymph node metastasis. Currently, there is no universally accepted approach for treating patients with pancreatic cancer in the neoadjuvant setting. In this review, the most common neoadjuvant strategies will be described, compared and discussed.
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Received: 4 February 2011; in revised form: 25 April 2011 / Accepted: 17 May 2011 / Published: 25 May 2011
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Abstract: Pancreatic cancer does not respond to a single-agent imatinib therapy. Consequently, multimodality treatments are contemplated. Published data indicate that in colorectal cancer, imatinib and radioimmunotherapy synergize to delay tumor growth. In pancreatic cancer, the tumor response is additive. This disparity of outcomes merited further studies because interactions between these modalities depend on the imatinib-induced reduction of the tumor interstitial fluid pressure. The examination of human and murine PDGFr-β/PDGF-B pathways in SW1990 pancreatic cancer xenografts revealed that the human branch is practically dormant in untreated tumors but the insult on the stromal component produces massive responses of human cancer cells. Inhibition of the stromal PDGFr-β with imatinib activates human PDGFr-β/PDGF-B signaling loop, silent in untreated xenografts, via an apparent paracrine rescue pathway. Responses are treatment- and time-dependent. Soon after treatment, levels of human PDGFr-β, compared to untreated tumors, are 3.4×, 12.4×, and 5.7× higher in imatinib-, radioimmunotherapy + imatinib-, and radioimmunotherapy-treated tumors, respectively. A continuous 14-day irradiation of imatinib-treated xenografts reduces levels of PDGFr-β and phosphorylated PDGFr-β by 5.3× and 4×, compared to earlier times. Human PDGF-B is upregulated suggesting that the survival signaling via the autocrine pathway is also triggered after stromal injury. These findings indicate that therapies targeting pancreatic cancer stromal components may have unintended mitogenic effects and that these effects can be reversed when imatinib is used in conjunction with radioimmunotherapy.
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Last update: 26 September 2012
