Current Knowledge on Pancreatic Cancer

Pancreatic cancer is the fourth leading cause of cancer death with a median survival of 6 months and a dismal 5-year survival rate of 3–5%. The development and progression of pancreatic cancer are caused by the activation of oncogenes, the inactivation of tumor suppressor genes, and the deregulation of many signaling pathways. Therefore, the strategies targeting these molecules as well as their downstream signaling could be promising for the prevention and treatment of pancreatic cancer. However, although targeted therapies for pancreatic cancer have yielded encouraging results in vitro and in animal models, these findings have not been translated into improved outcomes in clinical trials. This failure is due to an incomplete understanding of the biology of pancreatic cancer and to the selection of poorly efficient or imperfectly targeted agents. In this review, we will critically present the current knowledge regarding the molecular, biochemical, clinical, and therapeutic aspects of pancreatic cancer

Gene expression profiling by DNA microarray analysis in mouse embryonic fibroblasts transformed by ras(V12 )mutated protein and the E1A oncogene

BACKGROUND: Ras is an area of intensive biochemical and genetic studies and characterizing downstream components that relay ras-induced signals is clearly important. We used a systematic approach, based on DNA microarray technology to establish a first catalog of genes whose expression is altered by ras and, as such, potentially involved in the regulation of cell growth and transformation. RESULTS: We used DNA microarrays to analyze gene expression profiles of ras(V12)/E1A-transformed mouse embryonic fibroblasts. Among the ~12,000 genes and ESTs analyzed, 815 showed altered expression in ras(V12)/E1A-transformed fibroblasts, compared to control fibroblasts, of which 203 corresponded to ESTs. Among known genes, 202 were up-regulated and 410 were down-regulated. About one half of genes encoding transcription factors, signaling proteins, membrane proteins, channels or apoptosis-related proteins was up-regulated whereas the other half was down-regulated. Interestingly, most of the genes encoding structural proteins, secretory proteins, receptors, extracellular matrix components, and cytosolic proteins were down-regulated whereas genes encoding DNA-associated proteins (involved in DNA replication and reparation) and cell growth-related proteins were up-regulated. These data may explain, at least in part, the behavior of transformed cells in that down-regulation of structural proteins, extracellular matrix components, secretory proteins and receptors is consistent with reversion of the phenotype of transformed cells towards a less differentiated phenotype, and up-regulation of cell growth-related proteins and DNA-associated proteins is consistent with their accelerated growth. Yet, we also found very unexpected results. For example, proteases and inhibitors of proteases as well as all 8 angiogenic factors present on the array were down-regulated in transformed fibroblasts although they are generally up-regulated in cancers. This observation suggests that, in human cancers, proteases, protease inhibitors and angiogenic factors could be regulated through a mechanism disconnected from ras activation. CONCLUSIONS: This study established a first catalog of genes whose expression is altered upon fibroblast transformation by ras(V12)/E1A. This catalog is representative of the genome but not exhaustive, because only one third of expressed genes was examined. In addition, contribution to ras signaling of post-transcriptional and post-translational modifications was not addressed. Yet, the information gathered should be quite useful to future investigations on the molecular mechanisms of oncogenic transformation

The WSB1 Gene Is Involved in Pancreatic Cancer Progression

Pancreatic cancer cells generate metastases because they can survive the stress imposed by the new environment of the host tissue. To mimic this process, pancreatic cancer cells which are not stressed in standard culture conditions are injected into nude mice. Because they develop xenografts, they should have developed adequate stress response. Characterizing that response might provide new strategies to interfere with pancreatic cancer metastasis.In the human pancreatic cancer cell lines Panc-1, Mia-PaCa2, Capan-1, Capan-2 and BxPC3, we used Affymetrix DNA microarrays to compare the expressions of 22.000 genes in vitro and in the corresponding xenografts. We identified 228 genes overexpressed in xenografts and characterized the implication of one of them, WSB1, in the control of apoptosis and cell proliferation. WSB1 generates 3 alternatively spliced transcripts encoding distinct protein isoforms. In xenografts and in human pancreatic tumors, global expression of WSB1 mRNA is modestly increased whereas isoform 3 is strongly overexpressed and isoforms 1 and 2 are down-regulated. Treating Mia-PaCa2 cells with stress-inducing agents induced similar changes. Whereas retrovirus-forced expression of WSB1 isoforms 1 and 2 promoted cell growth and sensitized the cells to gemcitabine- and doxorubicin-induced apoptosis, WSB1 isoform 3 expression reduced cell proliferation and enhanced resistance to apoptosis, showing that stress-induced modulation of WSB1 alternative splicing increases resistance to apoptosis of pancreatic cancer cells.Data on WSB1 regulation support the hypothesis that activation of stress-response mechanisms helps cancer cells establishing metastases and suggest relevance to cancer development of other genes overexpressed in xenografts

The reg4 Gene, Amplified in the Early Stages of Pancreatic Cancer Development, Is a Promising Therapeutic Target

BACKGROUND: The aim of our work was to identify the genes specifically altered in pancreatic adenocarcinoma and especially those that are altered early in cancer development. METHODOLOGY/PRINCIPAL FINDINGS: Gene copy number was systematically assessed with an ultra-high resolution CGH oligonucleotide microarray in DNA from samples of pancreatic cancer. Several new cancer-associated variations were observed. In this work we focused on one of them, involving the reg4 gene. Gene copy number gain of the reg4 gene was confirmed by qPCR in 14 cancer samples. It was also found with increased copy number in most PanIN3 samples. The relationship betweena gain in reg4 gene copy number and cancer development was investigated on the human pancreatic cancer cell line Mia-PaCa2 xenografted under the skin of nude mice. When cells were transfected with a vector allowing reg4 expression, they generated tumors almost twice larger in size. In addition, these tumors were more resistant to gemcitabine treatment than control tumors. Interestingly, weekly intraperitoneal administration of a monoclonal antibody to reg4 halved the size of tumors generated by Mia-PaCa2 cells, suggesting that the antibody interfered with a paracrine/autocrine mechanism involving reg4 and stimulating cancer progression. The addition of gemcitabine resulted in further reduction, tumors becoming 5 times smaller than control. Exposure to reg4 antibody resulted in a significant decrease in intra-tumor levels of pAkt, Bcl-xL, Bcl-2, survivin and cyclin D1. CONCLUSIONS/SIGNIFICANCE: It was concluded that adjuvant therapies targeting reg4 could improve the standard treatment of pancreatic cancer with gemcitabine

Recherche de gènes de réponse au stress et leur implication dans les pathologies pancréatiques

Le laboratoire étudie les mécanismes de réponse au stress au cours des maladies pancréatiques, en particulier l adénocarcinome et la pancréatite aiguë. Nous pensons qu une cellule cancéreuse ne formera une métastase que si elle est capable de résister au stress induit par le nouvel environnement auquel elle sera exposée. Pour identifier les gènes impliqués dans ce mécanisme, nous avons injecté des lignées pancréatiques chez la souris nude et sélectionné les gènes surexprimés dans les xénogreffes. Parmi ceux-ci figure le gène WSB1 dont l expression des trois isoformes est modulée, non seulement dans les xénogreffes mais aussi in vitro en réponse au stress. Son originalité vient du fait que l expression est régulée par une réorientation majeure de l épissage alternatif en faveur de l isoforme 3. Cela a pour effet de ralentir la prolifération cellulaire mais aussi de faciliter la résistance à l apoptose induite par deux agents de himiothérapie, ce qui pourrait contribuer à la progression des tumeurs pancréatiques. L analyse de l expression des trois isoformes dans des adénocarcinomes pancréatiques humains supporte cette idée puisque l isoforme 3 y est largement prédominante. Un second projet concerne la relation entre autophagie et pancréatite aiguë. La pancréatite est associée à des modifications morphologiques ressemblant à des vacuoles autophagiques. Nous avons montré que VMP1, protéine induite au cours de la pancréatite aiguë, ainsi que TP53INP2 (paralogue de TP53INP1 également induite au cours de la pancréatite), sont nécessaires à la formation des vacuoles autophagiques. Ces observations suggèrent une implication de l autophagie dans le développement de la pancréatite.The main objective of our laboratory is to study stress response mechanisms during pancreatic disease, especially pancreatic adenocarcinoma and acute pancreatitis. We made the hypothesis that pancreatic cancer metastases occur only if they can survive the stress imposed by the new environment of the host tissue. In order to identify the genes involved in this process, we injected pancreatic cancer cells into nude mice and identified genes overexpressed in the xenografts. WSB1 was one of them. It showed the same altered expression in vitro under stress conditions. Interestingly, this gene is expressed as three different splice variants and expression of soform 3 was enhanced under stress conditions. This resulted in reduced cell proliferation and facilitated resistance to apoptosis induced by two chemotherapeutic agents, which could contribute to pancreatic tumor growth. Analyzing the expression of the three isoforms in human pancreatic adenocarcinomas supported this hypothesis since isoform 3 was found largely prevalent. The second part of the work addresses the relationship between autophagy and acute pancreatitis. Pancreatitis is associated with morphological changes in pancreatic cells reminding of autophagic conditions, such as vacuole formation. We showed that VMP1, a protein induced during acute pancreatitis, and TP53INP2 (paralogue of TP53INP1, also induced during pancreatitis), were necessary for the formation of autophagic vacuoles. These observations suggest that autophagy is actually involved in the development of pancreatitis.AIX-MARSEILLE2-BU Sci.Luminy (130552106) / SudocSudocFranceF

Fonction antitumorale d'ARGBP2 dans le cancer du pancreas par inhibition de l'adhésion et de la migration cellulaire

Le mauvais pronostic du cancer du pancréas est dû à son extension locorégionale rapide, à la rapidité d apparition des métastases à distance et à la faible efficacité des chimiothérapies actuelles. A ce jour, l identification d oncogènes ou de gènes suppresseurs impliqués dans la maladie n a pas permis d aboutir à des traitements efficaces. Nous avons montré qu ArgBP2 (Arg-binding protein 2) module les évènements cellulaires impliqués dans l invasivité de ce cancer. ArgBP2 est une protéine multiadaptatrice impliquée dans la régulation du cytosquelette d actine. ArgBP2 contrôle l adhérence et la migration des cellules tumorales par le biais de la régulation de WAVE-1, un activateur du complexe de nucléation de l actine. ArgBP2 facilite l interaction de c-Abl ou PTP-PEST avec WAVE-1, favorisant ainsi sa phosphorylation ou sa déphosphorylation. L utilisation du double hybride chez la levure nous a permis d identifier de nouvelles protéines interagissant avec ArgBP2, dont CIP4 (Cdc42-interacting protein 4). CIP4 interagit avec ArgBP2 et WAVE-1. CIP4 augmente aussi la phosphorylation de WAVE-1 par c-Abl et agit donc en synergie avec ArgBP2. La création d un mutant d ArgBP2 sur 5 résidus tyrosines a montré le rôle essentiel de la phosphorylation d ArgBP2 dans la régulation de sa fonction. L identification de nouveaux complexes multiprotéiques impliqués dans la migration cellulaire pourrait aboutir au développement de cibles thérapeutiques attractives dans le cancer du pancréas.AIX-MARSEILLE2-BU Sci.Luminy (130552106) / SudocSudocFranceF

SIP/TP53INP1, un nouveau gène de stress, régule positivement p53 pour induire l'arrêt du cycle cellulaire et l'apoptose

AIX-MARSEILLE2-BU Sci.Luminy (130552106) / SudocSudocFranceF

Gene expression profiling of tumours derived from rasV12/E1A-transformed mouse embryonic fibroblasts to identify genes required for tumour development.

BACKGROUND: In cancer, cellular transformation is followed by tumour development. Knowledge on the mechanisms of transformation, involving activation of proto-oncogenes and inactivation of tumour-suppressor genes has considerably improved whereas tumour development remains poorly understood. An interesting way of gaining information on tumour progression mechanisms would be to identify genes whose expression is altered during tumour formation. We used the Affymetrix-based DNA microarray technology to analyze gene expression profiles of tumours derived from rasV12/E1A-transformed mouse embryo fibroblasts in order to identify the genes that could be involved in tumour development. RESULTS: Among the 12,000 genes analyzed in this study, only 489 showed altered expression during tumour development, 213 being up-regulated and 276 down-regulated. The genes differentially expressed are involved in a variety of cellular functions, including control of transcription, regulation of mRNA maturation and processing, regulation of protein translation, activation of interferon-induced genes, intracellular signalling, apoptosis, cell growth, angiogenesis, cytoskeleton, cell-to-cell interaction, extracellular matrix formation, metabolism and production of secretory factors. CONCLUSIONS: Some of the genes identified in this work, whose expression is altered upon rasV12/E1A transformation of MEFs, could be new cancer therapeutic targets

Pancreatitis-associated protein I Suppresses NF-κB activation through a JAK/STAT-mediated mechanism in epithelial cells

Pancreatitis-associated protein I (PAP I), also known as HIP, p23, or Reg2 protein, has recently been implicated in the endogenous regulation of inflammation. Although it was initially characterized as a protein that is overexpressed in acute pancreatitis, PAP I has also been associated with a number of inflammatory diseases, such as Crohn's disease. Knowing thai PAP I and IL-10 responses share several features, we have used a pancreatic acinar cell line (AR42J) to assess the extent to which their expression is reciprocally regulated, and whether the JAK/STAT and NF-κB signaling pathways are involved in the suppression of inflammation mediated by PAP I. We observed that PAP I is induced in epithelial cells by IL-10 and by PAP I itself. In contrast, we found phosphorylation and nuclear translocation of STAT3 and induction of suppressor of cytokine signaling 3 in response to PAP I exposure. Finally, a JAK-speciflc inhibitor, tyrphostin AG490, markedly prevented PAP I-induced NF-κB inhibition, pointing to a cross-talk between JAK/STAT3 and NF-κB signaling pathways. Together, these findings indicate that PAP I inhibits the inflammatory response by blocking NF-κB activation through a STAT3-dependent mechanism. Important functional similarities to the anti-inflammatory cytokine IL-10 suggest that PAP I could play a role similar to that of IL-10 in epithelial cells. Copyright © 2006 by The American Association of Immunologists, Inc.This work was supported by Fondo de Investigaciones Sanitarias Grant PI020286 from the Spanish Ministry of Health and Consejo Superior Investigaciones Cientificas/Institut National de la Santé et de la Recherche Médical Grant 2003FR0006. S.G. was the recipient of an Institut d’Investigacions Biomèdiques August Pi i Sunyer predoctoral grant. E.F.-P. is the recipient of a Ramon y Cajal contractPeer Reviewe