Abstracts / Pancreatology 13 (2013) S2–S98 S91

EMT and stemness were assessed in human and murine pancreatic cancermodels using migration/invasion and spheroid assay.

Results: Here, we identified antidromic NFATc1 and p53 transcrip-tional network control over EMT and stemness. We show that p53 acti-vation prevents cells from EMT in amiR200c dependent manner. However,disruption of the tumor suppressor pathway enables NFATc1/Sox2 chro-matin complex formation and transcription of EMT programmes, resultingin highly invasive and metastatic PDACs. Finally, re-expression of miR200cor NFATc1 inactivation suppresses EMT/stemness genes and re-sensitizesPDAC to chemotherapy.

Conclusion: Antidromic NFATc1 and p53 signaling pathways controlkey features of cellular plasticity and tumor progression at the level of genetranscription. These findings implicate key roles for NFATc1 in transcrip-tional regulation of differentiation and self-renewal in PDAC.

S-5 Abstract id: 247.

Serotonin regulates progenitor cell-based but not clonal regenerationin the adult pancreatic acinar cell

Enrica Saponara, Sabrina Sonda, Kamile Grabliauskaite, TheresiaReding, Rolf Graf.

Swiss HPB Center, Visceral & Transplantation Surgery, UniversityHospital Zurich, Switzerland

Introduction: Progenitor cell-based regeneration of acinar cells isactivated during cerulein-induced pancreatitis. This process requiresacinar de-differentiation via secretion of zymogen content, followed byexpression of progenitor cell markers and formation of acinar-to-ductalmetaplasia (ADM). Clonal regeneration without loss of zymogen contentand cell de-differentiation is observed following 60% pancreatectomy.

Aims:Wepreviously showed that serotonin (5-HT) is essential for acinarcell secretion with a strong impact on the pathophysiology of acutepancreatitis; we now investigate the role of 5-HT in pancreatic regeneration.

Patients & methods: Cerulein-induced pancreatitis and 60% pancre-atectomy were performed in wild type (WT) and tryptophan hydroxylase-1 knock-out (TPH1-/-) mice, with reduced peripheral levels of 5-HT. Theregenerative potential of pancreatic acinar cells was evaluated in vivo, overa period of two weeks.

Results: After experimental pancreatitis, WTmice showed an early up-regulation of 5-HT2A/5-HT2B receptors, amylase secretion and progenitorcell marker expression, indicative of acinar de-differentiation. Theseevents were followed by the appearance of ADM lesions and acinar cellproliferation. Conversely, in TPH1-/- mice these early parameters wereblunted and consequent formation of ADM and proliferation of acinar cellswere inhibited. After 60% pancreatectomy, clonal regeneration of differ-entiated acinar cell was comparable in the two strains. Similarly to whatwas observed in vivo, 5-HT2A/5-HT2B receptor agonist promoted prolif-eration only in de-differentiated but not in dexamethasone-differentiatedAR42J cells.

Conclusion: Our results indicate that 5-HT, likely via 5-HT2A/5-HT2Breceptors, modulates progenitor cell-based but not clonal regeneration.Current investigations aim to elucidate the role of 5-HT in pancreaticproliferation induced by primary mitogen administration.

S-6 Abstract id: 19.

Effect of cystathionine-gamma-lyase gene deletion in caerulein-induced acute pancreatitis in the mouse

Madhav Bhatia, Abel Ang, Jack Rivers, Akhil Hegde.

University of Otago, Christchurch, New Zealand

Introduction: Hydrogen sulfide (H2S) has been reported to be involvedin the signaling of the inflammatory response; however there are differingviews as to whether it is pro- or anti-inflammatory.

Aims: The present study was aimed to investigate if endogenouslysynthesized H2S via cystathionine-g-lyase (CSE) plays a pro- or anti-in-flammatory role in caerulein-induced acute pancreatitis

Materials &methods: Acute Pancreatitis was induced in CSE knockout(CSE-/-) and wildtype (CSEþ/þ) mice by hourly caerulein injections (50 mg/kg) for 10 hours. Mice were sacrificed 1 h after the last caerulein injection.Blood, pancreas and lung tissues were collected and processed to measurethe plasma amylase, plasma H2S, myeloperoxidase (MPO) activities andprostaglandin E2 and cytokine levels in pancreas and lung.

Results: CSE-/- mice showed significantly less local pancreatic damageas well as acute pancreatitis-associated lung injury in comparison to theCSEþ/þ mice. There were also lower levels of pancreatic eicosanoid andchemokines in the CSE-/-mice when compared with CSEþ/þ mice. Addi-tionally, in CSEþ/þ mice, there was a greater level of pancreatic CSEexpression and sulfide synthesizing activity in caerulein-induced whencompared to the saline control. When comparing the two saline treatedcontrol groups, the CSE-/- mice showed significantly less pancreatic H2Ssynthesizing activity relative to the CSEþ/þ mice.

Conclusion: These data provide evidence that endogenous H2Sgenerated by CSE plays a key pro-inflammatory role in caerulein-inducedpancreatitis and its genetic deletion affords significant protection againstacute pancreatitis and associated lung injury.

S-7 Abstract id: 214.

Acinar specific TGF-b signaling regulates acinar cell regenerationCate-gory: Basic science - chronic pancreatitis.

Kamile Grabliauskaite, Theresia Reding, Enrica Saponara, SabrinaSonda, Rolf Graf.

Hospital Zurich, Switzerland

Introduction: TGF-b signaling is implicated in many pathophysiolog-ical functions of pancreatic cells, including regulation of regeneration andfibrosis. However, the function of TGF-b signaling is strongly context-dependent and an acinar cell specific role of this molecule in modulatingregeneration has not been completely investigated before.

Aims: In this study we aim to determine the contribution of TGFbsignaling to acinar cell proliferation during pancreatitis by using micedeficient in TGFb receptor II (TGFbRII fl/fl) exclusively in acinar cells.

Materials & methods: Pancreatitis was induced in control and PTF1b-CreTg; TGFbRIIfl/fl mice by multiple injections of cerulein. The expression ofproliferation markers, cell cycle regulators, and the severity of tissue inflam-mation and fibrosis were analysed by immunohistochemistry and qRT-PCR.

Results: Ki67 and BrdU analyses revealed increased number of prolif-erating acinar cells inTGFbRIIfl/flmice. Surprisingly, immunohistochemistryshowed that expression of the cell cycle inhibitor p21WAF1/Cip1, one of themain targets of TGFb signaling, was comparable inWTand TGFbRIIfl/flmice.However, the expression of the cell cycle inhibitor p16INK4a increased onlyin control animals. In addition, we observed extended formation of acinar-to-ductal metaplasia, higher stellate cells activation and stronger fibrosis inTGFbRIIfl/fl mice. Also, analysis of pan-leukocyte infiltration demonstratedstronger inflammation in TGFbRIIfl/fl mice compared to control animals.

Conclusion: Our data revealed that TGFb signaling inhibits activationof acinar cell cycle and prevents excessive ADM formation. Additionally,the loss of TGFb signaling in acinar cells potentiates fibrogenic processesduring pancreatitis, suggesting the existence of a regulatory feedbackbetween acinar and stellate cells.

S-8 Abstract id: 147.

Pancreatic stellate cells promote the hapto-migration of pancreaticcancer cells through collagen I mediated activation of alpha2beta1 in-tegrin pathway

Jing Lu 1, Shaoxia Zhou 1, Marco Siech 2, Hansjoerg Habisch 1, ThomasSeufferlein 3, Max. Bachem 1.