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The microrna processing endoribonuclease dicer has altered expression in pancreatic ductal adenocarcinoma and prognostic implications
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Abstracts / Pancreatology 15 (2015) S1eS141
identified not only in invasive tumours, but also in early preinvasive pancreatic intraepithelial precursor lesions. The functional dynamics of myeloid cells during carcinogenesis is largely unknown. Aims: We aimed to systematically decipher phenotypic and transcriptional changes in the myeloid cells during carcinogenesis and tumor progression in a genetic mouse model of pancreatic cancer. Materials & methods: Using murine pancreatic myeloid cells isolated from the genetic mouse model at different time points during carcinogenesis, we examined both established markers of macrophage polarisation using RT-PCR and FACS as well as transcriptional changes focussing on miRNA profiling. Results: Myeloid cells isolated during carcinogenesis showed simultaneous increases of established M1 and M2 markers already in preinvasive PanIN precursor lesions and in invasive cancers, indicating that phenotypic changes of myeloid cells during carcinogenesis do not follow the established M1/M2 classification. miRNA profiling revealed distinct regulations of several miRNAs during carcinogenesis. Among them, miRNA-21 was significantly increased both in myeloid cells surrounding preinvasive PanIN lesions and invasive cancers. miRNA-21-5p and -3p altered expression of the immune modulators PDCD4 and MIP1A, respectively. This was associated with reduced attraction of cytotoxic T cells, indicating the miRNA-21 in tumor-infiltrating myeloid cells drives the establishment of an immune-suppressive tumor-promoting micromilieu. Conclusion: Phenotypic changes in tumor-infiltrating myeloid cells during tumor progression are associated with distinct miRNA patterns including upregulation of miRNA-21 which is modulating the inflammatory micromilieu thereby enhancing tumor progression.
1232. BPTF is required for c-MYC-driven pancreatic tumorigenesis Laia Richard Gines, Enrique Carrillo-de Santa Pau, nchez-Ar Monica P erez de Andr es, Victor Sa evalo Lobo, Francisco X. Real CNIO, Spain Introduction: Genetic mouse models (GEMM) of pancreatic ductal adenocarcinoma have shown that c-Myc is required for mutant Krasdriven initiation and tumor progression, underscoring its potential as a therapeutic target. Direct chemical inhibition of c-Myc has not proven feasible. Nonetheless, interfering with regulatory c-Myc cofactors e such as Brd4 e is a promising strategy for the treatment of c-Myc-dependent malignancies. Aims: To assess the role of BPTF (Bromodomain PHD Transcription Factor) in c-MYC-driven pancreatic tumorigenesis. Materials & methods: We have used co-immunoprecipitation, ChIPSeq, RNA-Seq and PDAC GEMMs to investigate the role of BPTF in tumor development in Ela-Myc mice. Results: c-Myc interacts with BPTF, a core subunit of the NURF chromatin remodelling complex. BPTF knockdown leads to a decrease in c-Myc binding to DNA, changes in chromatin accessibility, and impaired activation of the c-Myc-driven transcriptional program. Furthermore, BPTF expression in human tumors correlates positively with activation of c-Myc gene signatures. Upon Bptf inactivation in E10.5 pancreas, we found no major changes in histology or acinar gene expression. Strikingly, Bptf deletion in Ela-Myc mice led to an extensive loss of acinar cells without deterioration of the endocrine function. Bptf inactivation in 5-7 week-old Ela-Myc mice (through the Ptf1a-CreERT2 recombinase) was associated with a significant delay in tumor onset and increased survival. Conclusion: BPTF is exquisitely required for the survival of c-Mycoverexpressing acinar cells and for Myc-driven tumor progression, but not for normal acinar cell function. These results highlight the therapeutic potential of exploiting the Bptf-Myc axis in cancer therapy.
977. DNA cytometry as a new tool for differentiation between intraductal papillary mucinous neoplasia of low and medium grade dysplasia? correlation with preoperative diagnostic imaging Wladimir Faber 1, Christian Juergensen 2, Anja Schirmeier 1, Hussein Al-Abadi 1, Fritz Klein 1, Thula Cannon Walter 3, Christian Grieser 3, Johann Pratshke 1, Timm Denecke 3, Marcus Bahra 1 1
Department of General, Visceral and Transplantation Surgery, e Universita €tsmedizin Berlin, Campus Virchow Klinikum, Charite Germany 2 Department of Gastroenterology, Infectious Diseases and Mitte, Charite e Universita €tsmedizin Rheumatology, Campus Charite Berlin, Germany 3 e Universit€ Klinik für Radiologie, Charite atsmedizin Berlin, Germany Introduction: Cystic lesions of pancreas are now being diagnosed more frequently in recent times. The indication for resection is usually provided by sectional imaging and specific criteria, such as the Sendai criteria. Chromosomal anomalies are observed in many different solid carcinomas, and the DNA index has proven to be a predictive tool in several human cancers. Aims: The aim of this study was to analyze the significance of DNA cytometry for differentiation between IPMN low grade dysplasia and IPMN medium grade dysplasia. Patients & methods: A total of 16 patients who underwent pancreatic resection due to an IPMN were included in this study. In addition to routine histopathologic analysis, the DNA index and DNA ploidy were determined using DNA image cytometry. The histopathological findings and preoperative Sendai criteria were compared with the results of the DNA analysis. Results: All of the patients with IPMN-B showed aneuploide histograms with DNA indices 1.3, whereas all of the patients with IPMN-A showed DNA indices 1.3. The median of positive Sendai criteria was 0 by patients with IPMN-A. By patients with IPMN-B the median of positive Sendai criteria was 1. Conclusion: In the diagnostic work up of IPMNs the determination of DNA index is a useful diagnostic extend. In our patients, postoperative measured ploidy status was precisely correlated with the postoperative histopathological situation (aneuploidy ¼ IPMN-B) and was significantly superior to the preoperative Sendai criteria. Therefore, preoperative DNA image cytometry may represent a useful diagnostic addition for the indication and surveillance of patients with IPMN in the future.
1242. The microrna processing endoribonuclease dicer has altered expression in pancreatic ductal adenocarcinoma and prognostic implications Adam Frampton 1, Niccola Funel 2, Elisa Giovannetti 3, Raida Ahmad 1, Leandro Castellano 1, Jonathan Krell 1, Long R. Jiao 1, Justin Stebbing 1 1
Imperial College, United Kingdom University of Pisa, Italy 3 VU Cancer Center, Netherlands 2
Introduction: Aberrant microRNA (miRNA) expression has been associated with aggressiveness, chemoresistance and prognosis in pancreatic ductal adenocarcinoma (PDAC) patients. DICER is the enzyme complex crucial for the maturation of miRNAs; therefore its’ altered expression may contribute to tumor initiation and progression. Several studies have associated altered DICER expression with prognosis in various tumor types.
Abstracts / Pancreatology 15 (2015) S1eS141
Aims: We aimed to investigate DICER expression in PDAC. Patients & methods: We evaluated DICER expression by immunohistochemistry (IHC) in matched normal, PDAC and lymph-node positive resected specimens (all n¼19). We used a novel IHC scoring system, whereby tumor and lymph-node expression was normalized to DICER levels in the normal adjacent pancreas. Scoring of positive cells was calculated by evaluating the number of positive cells (score 0-3), plus their intensity (score 0-3). Differential expression of DICER (DE-DICER) in tumor and lymph-nodes was correlated with clinicopathologic factors, and disease-free survival (DFS) and overall survival (OS). Results: Patients were grouped according to high DE-DICER (HDEDICER) or low DE-DICER (LDE-DICER). HDE-DICER was observed in 10 tumors and 11 lymph-nodes. Mean values of DFS in HDE-DICER and LDEDICER were 7.77 months and 16.15 months respectively (P¼0.017). HDEDICER was associated with advancing tumor stage (P¼0.037). Conclusion: HDE-DICER expression seems to be associated with reduced DFS after PDAC resection. Alterations in DICER levels and miRNA processing could lead to differential expression of oncogenic and tumor suppressor miRNAs and lead to a more aggressive phenotype. We are validating these findings in large independent cohorts from Germany (n¼121) and Italy (n¼125).
988. ZEB1 regulates DNA damage response during gemcitabine treatment in PDACs cells Ilaria Passacantilli 1, Sara Calabretta 1, Gabriele Capurso 1, Gianfranco Delle Fave 1, Claudio Sette 2 1
Sapienza University of Rome, Digestive and Liver Disease Unit, Italy University of Rome Tor Vergata, Department of Biomedicin and Prevention, Italy 2
Introduction: Pancreatic ductal adenocarcimoma (PDAC) is characterised by limited response to chemotherapy and poor prognosis. Chemoresistance may rely in enhanced activation of DNA Damage Response (DDR) pathways, which confers an increased ability to maintain genome stability to cancer cells. Moreover, Epithelial-to-Mesenchymal transition (EMT) affects the response to chemotherapeutic drugs. Among the EMTrelated factors, ZEB1 is important for chemoresistance in PDAC cells. Thus, ZEB1 and DDR effectors may cooperate to confer drug resistance in PDAC cells. Aims: To investigate how ZEB1 contributes to drug resistance. Patients & methods: Colony Assay; RT-PCR; Western blot; Immunofluorescence; RNA-interference in PDAC cells; Trypan Blue cell count. Results: We used PDAC cell lines displaying different sensitivity to gemcitabine, the elective drug for PDAC. Colony assays and analysis of PARP protein cleavage indicated that HPAF-II cells were less resistant to gemcitabine than MiaPaCa-2 cells. RT-PCR and western Blot analyses showed that the higher sensitivity of HPAF-II to gemcitabine correlates with expression of the epithelial marker E-cadherin, whereas MiaPaCa-2 cells express the mesenchymal marker vimentin. Among the EMT-related transcription factors, only ZEB1 clearly segregated the epithelial-like HPAF-II (low) from the mesenchymal-like MiaPaCa-2 (high). Silencing of ZEB1 restored sensitivity to gemcitabine in MiaPaCa-2 cells, albeit they did not revert to the epithelial phenotype. Notably, gemcitabine induced stronger phosphorylation of the DDR effector CHK2 in MiaPaCa-2 than in HPAF-II, in a ZEB1-dependent manner. No significant differences in CHK1 phosphorylation were observed. Conclusion: ZEB1 and CHK2 may cooperate to confer resistance to gemcitabine treatment and may represent suitable therapeutic targets for PDAC.
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990. Argyrin F therapy attenuates carcinogenesis of pancreatic ductal adenocarcinoma (PDAC) X.I. Chen 1, Samarpita Barat 1, Przemyslaw Bozko 1, Bence Sipos 2, Markus Kalesse 3, Nisar Malek 1, Ruben Plentz 1 1 Department of Internal Medicine I, Medical University Hospital, Tuebingen, Germany 2 Institute of Pathology, University of Tuebingen, Germany 3 Institute of Organic Chemistry & Centre of Biomolecular Drug €t Hannover, Germany Research, Leibniz Universita
Introduction: PDAC is an aggressive disease with a 5-year survival rate of <5%. New therapeutic approaches are higly needed. Recent studies have reported that the proteasome inhibitor Argyrin A, a cyclic peptide derived from the myxobacterium Archangium gephyra, show antitumoral activities. Aims: The aim of the present study is to explore the anti-tumor activity of his analogue Argyrin F in PDAC carcinogenesis. Patients & methods: In vitro, we analyzed the effect of Argyrin F by testing different dosages on PDAC cell's growth and epithelial plasticity by using WST-1 assay, wound healing assay, invasion assay, colony formation assay, apoptosis assay and Western Blot. In vivo, we assessed the effects of Argyin F in a genetically engineered mouse model (Pdx1- Cre; LSLKrasG12D; p53 lox/þ) of PDAC. Results: Treatment with Argyrin F significantly impaired cell proliferation, migration, invasion and soft agar growth compared to therapy with DMSO. We also found that Argyrin F impairs epithelial mesenchymal transition (EMT) and induces apoptosis in a dose-and time-dependent manner. Most importantly, Argyrin F treatment showed prolonged survival and caused significant tumor reduction. Conclusion: Our work demonstrate that treatment with Argyrin F can successfully attenuates the carcinogenesis of PDAC cells in vitro and in vivo and might be a new and promising drug for human PDAC.
1246. Role of HNF6 in the initiation of pancreatic ductal adenocarcinoma Patrick Jacquemin, C ecile Augereau, Fr ed eric Lemaigre de Duve Institute, LPAD Unit, Belgium Introduction: Acinar-to-ductal metaplasia (ADM), a process where pancreatic acinar cells are converted to duct-like cells, is considered a precursor lesion of pancreatic ductal adenocarcinoma (PDAC). It may evolve to intraepithelial neoplastic lesions (PanINs) and eventually to PDAC, when it is associated with an activating mutation of K-ras in metaplastic acinar cells. Here we investigate potential mechanisms leading to ADM and explore the possibility that perturbation of ductal homeostasis can induce ADM, and possibly PanIN. Aims: Loss-of-function of the transcription factor HNF6 in knockout mice is associated with perturbed differentiation of pancreatic duct cells. In the present work, we study whether perturbed ductal homeostasis can induce ADM and PanIN. Materials & methods: Sox9CreER HNF6f/- mice in which HNF6 is specifically deleted in ductal cells were used. The HNF6 gene was inactivated after birth by tamoxifen injections. Phenotypic characterization was performed by histological and immunostaining analyses. Results: Three weeks after birth, dilated ducts were seen in the mice; they were surrounded by a large amount of collagen-expressing cells. The expression of HNF1b, a transcription factor important for duct cell differentiation, was reduced in duct cells. We also observed adipocyte infiltration in the acinar tissue. Acinar cell proliferation was increased, and ADM, characterized by reduced expression of the acinar transcription factor Ptf1a and ectopic expression of ErbB2, was also detected. The phenotype worsened with aging, culminating in acinar paucity and massive fat infiltration in 6-month-old mice. Conclusion: This study indicates that perturbed duct cell homeostasis can induce ADM and lipomatosis, two lesions often associated with PDAC in humans.
Abstracts / Pancreatology 15 (2015) S1eS141
identified not only in invasive tumours, but also in early preinvasive pancreatic intraepithelial precursor lesions. The functional dynamics of myeloid cells during carcinogenesis is largely unknown. Aims: We aimed to systematically decipher phenotypic and transcriptional changes in the myeloid cells during carcinogenesis and tumor progression in a genetic mouse model of pancreatic cancer. Materials & methods: Using murine pancreatic myeloid cells isolated from the genetic mouse model at different time points during carcinogenesis, we examined both established markers of macrophage polarisation using RT-PCR and FACS as well as transcriptional changes focussing on miRNA profiling. Results: Myeloid cells isolated during carcinogenesis showed simultaneous increases of established M1 and M2 markers already in preinvasive PanIN precursor lesions and in invasive cancers, indicating that phenotypic changes of myeloid cells during carcinogenesis do not follow the established M1/M2 classification. miRNA profiling revealed distinct regulations of several miRNAs during carcinogenesis. Among them, miRNA-21 was significantly increased both in myeloid cells surrounding preinvasive PanIN lesions and invasive cancers. miRNA-21-5p and -3p altered expression of the immune modulators PDCD4 and MIP1A, respectively. This was associated with reduced attraction of cytotoxic T cells, indicating the miRNA-21 in tumor-infiltrating myeloid cells drives the establishment of an immune-suppressive tumor-promoting micromilieu. Conclusion: Phenotypic changes in tumor-infiltrating myeloid cells during tumor progression are associated with distinct miRNA patterns including upregulation of miRNA-21 which is modulating the inflammatory micromilieu thereby enhancing tumor progression.
1232. BPTF is required for c-MYC-driven pancreatic tumorigenesis Laia Richard Gines, Enrique Carrillo-de Santa Pau, nchez-Ar Monica P erez de Andr es, Victor Sa evalo Lobo, Francisco X. Real CNIO, Spain Introduction: Genetic mouse models (GEMM) of pancreatic ductal adenocarcinoma have shown that c-Myc is required for mutant Krasdriven initiation and tumor progression, underscoring its potential as a therapeutic target. Direct chemical inhibition of c-Myc has not proven feasible. Nonetheless, interfering with regulatory c-Myc cofactors e such as Brd4 e is a promising strategy for the treatment of c-Myc-dependent malignancies. Aims: To assess the role of BPTF (Bromodomain PHD Transcription Factor) in c-MYC-driven pancreatic tumorigenesis. Materials & methods: We have used co-immunoprecipitation, ChIPSeq, RNA-Seq and PDAC GEMMs to investigate the role of BPTF in tumor development in Ela-Myc mice. Results: c-Myc interacts with BPTF, a core subunit of the NURF chromatin remodelling complex. BPTF knockdown leads to a decrease in c-Myc binding to DNA, changes in chromatin accessibility, and impaired activation of the c-Myc-driven transcriptional program. Furthermore, BPTF expression in human tumors correlates positively with activation of c-Myc gene signatures. Upon Bptf inactivation in E10.5 pancreas, we found no major changes in histology or acinar gene expression. Strikingly, Bptf deletion in Ela-Myc mice led to an extensive loss of acinar cells without deterioration of the endocrine function. Bptf inactivation in 5-7 week-old Ela-Myc mice (through the Ptf1a-CreERT2 recombinase) was associated with a significant delay in tumor onset and increased survival. Conclusion: BPTF is exquisitely required for the survival of c-Mycoverexpressing acinar cells and for Myc-driven tumor progression, but not for normal acinar cell function. These results highlight the therapeutic potential of exploiting the Bptf-Myc axis in cancer therapy.
977. DNA cytometry as a new tool for differentiation between intraductal papillary mucinous neoplasia of low and medium grade dysplasia? correlation with preoperative diagnostic imaging Wladimir Faber 1, Christian Juergensen 2, Anja Schirmeier 1, Hussein Al-Abadi 1, Fritz Klein 1, Thula Cannon Walter 3, Christian Grieser 3, Johann Pratshke 1, Timm Denecke 3, Marcus Bahra 1 1
Department of General, Visceral and Transplantation Surgery, e Universita €tsmedizin Berlin, Campus Virchow Klinikum, Charite Germany 2 Department of Gastroenterology, Infectious Diseases and Mitte, Charite e Universita €tsmedizin Rheumatology, Campus Charite Berlin, Germany 3 e Universit€ Klinik für Radiologie, Charite atsmedizin Berlin, Germany Introduction: Cystic lesions of pancreas are now being diagnosed more frequently in recent times. The indication for resection is usually provided by sectional imaging and specific criteria, such as the Sendai criteria. Chromosomal anomalies are observed in many different solid carcinomas, and the DNA index has proven to be a predictive tool in several human cancers. Aims: The aim of this study was to analyze the significance of DNA cytometry for differentiation between IPMN low grade dysplasia and IPMN medium grade dysplasia. Patients & methods: A total of 16 patients who underwent pancreatic resection due to an IPMN were included in this study. In addition to routine histopathologic analysis, the DNA index and DNA ploidy were determined using DNA image cytometry. The histopathological findings and preoperative Sendai criteria were compared with the results of the DNA analysis. Results: All of the patients with IPMN-B showed aneuploide histograms with DNA indices 1.3, whereas all of the patients with IPMN-A showed DNA indices 1.3. The median of positive Sendai criteria was 0 by patients with IPMN-A. By patients with IPMN-B the median of positive Sendai criteria was 1. Conclusion: In the diagnostic work up of IPMNs the determination of DNA index is a useful diagnostic extend. In our patients, postoperative measured ploidy status was precisely correlated with the postoperative histopathological situation (aneuploidy ¼ IPMN-B) and was significantly superior to the preoperative Sendai criteria. Therefore, preoperative DNA image cytometry may represent a useful diagnostic addition for the indication and surveillance of patients with IPMN in the future.
1242. The microrna processing endoribonuclease dicer has altered expression in pancreatic ductal adenocarcinoma and prognostic implications Adam Frampton 1, Niccola Funel 2, Elisa Giovannetti 3, Raida Ahmad 1, Leandro Castellano 1, Jonathan Krell 1, Long R. Jiao 1, Justin Stebbing 1 1
Imperial College, United Kingdom University of Pisa, Italy 3 VU Cancer Center, Netherlands 2
Introduction: Aberrant microRNA (miRNA) expression has been associated with aggressiveness, chemoresistance and prognosis in pancreatic ductal adenocarcinoma (PDAC) patients. DICER is the enzyme complex crucial for the maturation of miRNAs; therefore its’ altered expression may contribute to tumor initiation and progression. Several studies have associated altered DICER expression with prognosis in various tumor types.
Abstracts / Pancreatology 15 (2015) S1eS141
Aims: We aimed to investigate DICER expression in PDAC. Patients & methods: We evaluated DICER expression by immunohistochemistry (IHC) in matched normal, PDAC and lymph-node positive resected specimens (all n¼19). We used a novel IHC scoring system, whereby tumor and lymph-node expression was normalized to DICER levels in the normal adjacent pancreas. Scoring of positive cells was calculated by evaluating the number of positive cells (score 0-3), plus their intensity (score 0-3). Differential expression of DICER (DE-DICER) in tumor and lymph-nodes was correlated with clinicopathologic factors, and disease-free survival (DFS) and overall survival (OS). Results: Patients were grouped according to high DE-DICER (HDEDICER) or low DE-DICER (LDE-DICER). HDE-DICER was observed in 10 tumors and 11 lymph-nodes. Mean values of DFS in HDE-DICER and LDEDICER were 7.77 months and 16.15 months respectively (P¼0.017). HDEDICER was associated with advancing tumor stage (P¼0.037). Conclusion: HDE-DICER expression seems to be associated with reduced DFS after PDAC resection. Alterations in DICER levels and miRNA processing could lead to differential expression of oncogenic and tumor suppressor miRNAs and lead to a more aggressive phenotype. We are validating these findings in large independent cohorts from Germany (n¼121) and Italy (n¼125).
988. ZEB1 regulates DNA damage response during gemcitabine treatment in PDACs cells Ilaria Passacantilli 1, Sara Calabretta 1, Gabriele Capurso 1, Gianfranco Delle Fave 1, Claudio Sette 2 1
Sapienza University of Rome, Digestive and Liver Disease Unit, Italy University of Rome Tor Vergata, Department of Biomedicin and Prevention, Italy 2
Introduction: Pancreatic ductal adenocarcimoma (PDAC) is characterised by limited response to chemotherapy and poor prognosis. Chemoresistance may rely in enhanced activation of DNA Damage Response (DDR) pathways, which confers an increased ability to maintain genome stability to cancer cells. Moreover, Epithelial-to-Mesenchymal transition (EMT) affects the response to chemotherapeutic drugs. Among the EMTrelated factors, ZEB1 is important for chemoresistance in PDAC cells. Thus, ZEB1 and DDR effectors may cooperate to confer drug resistance in PDAC cells. Aims: To investigate how ZEB1 contributes to drug resistance. Patients & methods: Colony Assay; RT-PCR; Western blot; Immunofluorescence; RNA-interference in PDAC cells; Trypan Blue cell count. Results: We used PDAC cell lines displaying different sensitivity to gemcitabine, the elective drug for PDAC. Colony assays and analysis of PARP protein cleavage indicated that HPAF-II cells were less resistant to gemcitabine than MiaPaCa-2 cells. RT-PCR and western Blot analyses showed that the higher sensitivity of HPAF-II to gemcitabine correlates with expression of the epithelial marker E-cadherin, whereas MiaPaCa-2 cells express the mesenchymal marker vimentin. Among the EMT-related transcription factors, only ZEB1 clearly segregated the epithelial-like HPAF-II (low) from the mesenchymal-like MiaPaCa-2 (high). Silencing of ZEB1 restored sensitivity to gemcitabine in MiaPaCa-2 cells, albeit they did not revert to the epithelial phenotype. Notably, gemcitabine induced stronger phosphorylation of the DDR effector CHK2 in MiaPaCa-2 than in HPAF-II, in a ZEB1-dependent manner. No significant differences in CHK1 phosphorylation were observed. Conclusion: ZEB1 and CHK2 may cooperate to confer resistance to gemcitabine treatment and may represent suitable therapeutic targets for PDAC.
S43
990. Argyrin F therapy attenuates carcinogenesis of pancreatic ductal adenocarcinoma (PDAC) X.I. Chen 1, Samarpita Barat 1, Przemyslaw Bozko 1, Bence Sipos 2, Markus Kalesse 3, Nisar Malek 1, Ruben Plentz 1 1 Department of Internal Medicine I, Medical University Hospital, Tuebingen, Germany 2 Institute of Pathology, University of Tuebingen, Germany 3 Institute of Organic Chemistry & Centre of Biomolecular Drug €t Hannover, Germany Research, Leibniz Universita
Introduction: PDAC is an aggressive disease with a 5-year survival rate of <5%. New therapeutic approaches are higly needed. Recent studies have reported that the proteasome inhibitor Argyrin A, a cyclic peptide derived from the myxobacterium Archangium gephyra, show antitumoral activities. Aims: The aim of the present study is to explore the anti-tumor activity of his analogue Argyrin F in PDAC carcinogenesis. Patients & methods: In vitro, we analyzed the effect of Argyrin F by testing different dosages on PDAC cell's growth and epithelial plasticity by using WST-1 assay, wound healing assay, invasion assay, colony formation assay, apoptosis assay and Western Blot. In vivo, we assessed the effects of Argyin F in a genetically engineered mouse model (Pdx1- Cre; LSLKrasG12D; p53 lox/þ) of PDAC. Results: Treatment with Argyrin F significantly impaired cell proliferation, migration, invasion and soft agar growth compared to therapy with DMSO. We also found that Argyrin F impairs epithelial mesenchymal transition (EMT) and induces apoptosis in a dose-and time-dependent manner. Most importantly, Argyrin F treatment showed prolonged survival and caused significant tumor reduction. Conclusion: Our work demonstrate that treatment with Argyrin F can successfully attenuates the carcinogenesis of PDAC cells in vitro and in vivo and might be a new and promising drug for human PDAC.
1246. Role of HNF6 in the initiation of pancreatic ductal adenocarcinoma Patrick Jacquemin, C ecile Augereau, Fr ed eric Lemaigre de Duve Institute, LPAD Unit, Belgium Introduction: Acinar-to-ductal metaplasia (ADM), a process where pancreatic acinar cells are converted to duct-like cells, is considered a precursor lesion of pancreatic ductal adenocarcinoma (PDAC). It may evolve to intraepithelial neoplastic lesions (PanINs) and eventually to PDAC, when it is associated with an activating mutation of K-ras in metaplastic acinar cells. Here we investigate potential mechanisms leading to ADM and explore the possibility that perturbation of ductal homeostasis can induce ADM, and possibly PanIN. Aims: Loss-of-function of the transcription factor HNF6 in knockout mice is associated with perturbed differentiation of pancreatic duct cells. In the present work, we study whether perturbed ductal homeostasis can induce ADM and PanIN. Materials & methods: Sox9CreER HNF6f/- mice in which HNF6 is specifically deleted in ductal cells were used. The HNF6 gene was inactivated after birth by tamoxifen injections. Phenotypic characterization was performed by histological and immunostaining analyses. Results: Three weeks after birth, dilated ducts were seen in the mice; they were surrounded by a large amount of collagen-expressing cells. The expression of HNF1b, a transcription factor important for duct cell differentiation, was reduced in duct cells. We also observed adipocyte infiltration in the acinar tissue. Acinar cell proliferation was increased, and ADM, characterized by reduced expression of the acinar transcription factor Ptf1a and ectopic expression of ErbB2, was also detected. The phenotype worsened with aging, culminating in acinar paucity and massive fat infiltration in 6-month-old mice. Conclusion: This study indicates that perturbed duct cell homeostasis can induce ADM and lipomatosis, two lesions often associated with PDAC in humans.