Necro-inflammatory response of pancreatic acinar cells in the pathogenesis of acute alcoholic pancreatitis

The role of pancreatic acinar cells in initiating necro-inflammatory responses during the early onset of alcoholic acute pancreatitis (AP) has not been fully evaluated. We investigated the ability of acinar cells to generate pro- and anti-inflammatory mediators, including inflammasome-associated IL-18/caspase-1, and evaluated acinar cell necrosis in an animal model of AP and human samples. Rats were fed either an ethanol-containing or control diet for 14 weeks and killed 3 or 24 h after a single lipopolysaccharide (LPS) injection. Inflammasome components and necro-inflammation were evaluated in acinar cells by immunofluorescence (IF), histology, and biochemical approaches. Alcohol exposure enhanced acinar cell-specific production of TNFα, IL-6, MCP-1 and IL-10, as early as 3 h after LPS, whereas IL-18 and caspase-1 were evident 24 h later. Alcohol enhanced LPS-induced TNFα expression, whereas blockade of LPS signaling diminished TNFα production in vitro, indicating that the response of pancreatic acinar cells to LPS is similar to that of immune cells. Similar results were observed from acinar cells in samples from patients with acute/recurrent pancreatitis. Although morphologic examination of sub-clinical AP showed no visible signs of necrosis, early loss of pancreatic HMGB1 and increased systemic levels of HMGB1 and LDH were observed, indicating that this strong systemic inflammatory response is associated with little pancreatic necrosis. These results suggest that TLR-4-positive acinar cells respond to LPS by activating the inflammasome and producing pro- and anti-inflammatory mediators during the development of mild, sub-clinical AP, and that these effects are exacerbated by alcohol injury.

Early epigenetic downregulation of WNK2 kinase during pancreatic ductal adenocarcinoma development

Pancreatic ductal adenocarcinoma (PDAC) is usually incurable. Contrary to genetic mechanisms involved in PDAC pathogenesis, epigenetic alterations are ill defined. Here, we determine the contribution of epigenetically silenced genes to the development of PDAC. We analyzed enriched, highly methylated DNAs from PDACs, chronic pancreatitis (CP) and normal tissues using CpG island microarrays and identified WNK2 as a prominent candidate tumor suppressor gene being downregulated early in PDAC development. WNK2 was further investigated in tissue microarrays, methylation analysis of early pancreatic intraepithelial neoplasia (PanIN), mouse models for PDAC and pancreatitis, re-expression studies after demethylation, and cell growth assays using WNK2 overexpression. Demethylation assays confirmed the link between methylation and expression. WNK2 hypermethylation was higher in tumor than in surrounding inflamed tissues and was observed in PanIN lesions as well as in a PDAC mouse model. WNK2 mRNA and protein expressions were lower in PDAC and CP compared with normal tissues both in patients and mouse models. Overexpression of WNK2 led to reduced cell growth, and WNK2 expression in tissues correlated negatively with pERK1/2 expression, a downstream target of WNK2 responsible for cell proliferation. Downregulation of WNK2 by promoter hypermethylation occurs early in PDAC pathogenesis and may support tumor cell growth via the ERK-MAPK pathway.

Yes-associated protein up-regulates Jagged-1 and activates the Notch pathway in human hepatocellular carcinoma

BACKGROUND & AIMS

Cancer cells often lose contact inhibition to undergo anchorage-independent proliferation and become resistant to apoptosis by inactivating the Hippo signaling pathway, resulting in activation of the transcriptional co-activator yes-associated protein (YAP). However, the oncogenic mechanisms of YAP activity are unclear.

METHODS

By using cross-species analysis of expression data, the Notch ligand Jagged-1 (Jag-1) was identified as a downstream target of YAP in hepatocytes and hepatocellular carcinoma (HCC) cells. We analyzed the functions of YAP in HCC cells via overexpression and RNA silencing experiments. We used transgenic mice that overexpressed a constitutively activated form of YAP (YAP(S127A)), and measured protein levels in HCC, colorectal and pancreatic tumor samples from patients.

RESULTS

Human HCC cell lines and mouse hepatocytes that overexpress YAP(S127A) up-regulated Jag-1, leading to activation of the Notch pathway and increased proliferation. Induction of Jag-1, activation of Notch, and cell proliferation required binding of YAP to its transcriptional partner TEA domain family member 4 (TEAD4); TEAD4 binding required the Mst1/2 but not β-catenin signaling. Levels of YAP correlated with Jag-1 expression and Notch signaling in human tumor samples and correlated with shorter survival times of patients with HCC or colorectal cancer.

CONCLUSIONS

The transcriptional regulator YAP up-regulates Jag-1 to activate Notch signaling in HCC cells and mouse hepatocytes. YAP-dependent activity of Jag-1 and Notch correlate in human HCC and colorectal tumor samples with patient survival times, suggesting the use of YAP and Notch inhibitors as therapeutics for gastrointestinal cancer. Transcript profiling: microarray information was deposited at the Gene Expression Omnibus database (http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?token=jxepvsumwosqkve&acc=GSE35004).

Abstract 2295: Succession of transiently active TIC clones drives long-term human pancreatic cancer progression

Despite accumulating evidence indicating a pivotal role of tumor-initiating cells (TIC) in tumor progression and metastases formation of pancreatic cancer (PC), very little is known about the clonal TIC dynamics within PC tumors in vivo. It is unclear whether the high aggressiveness of PC is driven by a homogeneous population of self-renewing TIC or whether distinct classes or activation states of TIC drive long-term disease progression. To address this we tracked the clonal contribution of individual TIC to tumor formation in vivo.

Serum-free adherent cultures were established allowing enrichment of PC TIC without restriction to a certain phenotype. These cultures grow as 3-dimensional epithelial colonies with tight cell-to-cell contacts und reliably form subcutaneous tumors in NSG mice. To induce differentiation of TIC, FBS was added and FGF2, FGF10 and Nodal were withdrawn. Under these conditions, irregular shaped cells form a monolayer and down regulate markers previously described for TIC or normal pancreatic progenitors. Strikingly, despite profound changes in morphology and marker expression tumor initiation and self-renewal of TIC in serial transplantation were unchanged. Moreover, sorted CD133+ and CD133− cells equally efficient formed tumors containing similar proportions of CD133+ in vivo. Together these data indicate an unexpected phenotypic plasticity of TIC in PC.

To determine the clonal kinetics of individual self-renewing TIC in vivo, early passage serum-free cultures from 3 patients were transduced with a lentiviral vector (LV) and serially transplanted. LV stably integrate into the host cell genome resulting in TIC clone specific fusion sequences which were identified by highly sensitive LAM-PCR and high throughput sequencing. In primary mice, 0.003-0.113% of all transduced cells contributed actively to tumor formation. Unexpectedly, in subsequent generations tumor formation was mainly driven by distinct TIC clones not detectable in earlier but recruited to tumor formation in later generations. Moreover, individual primary xenografts generated pairs of secondary tumors with very little overlap between clonal compositions. Mathematical modeling indicates strong changes in proliferative activity of individual, otherwise homogenous TIC which predominantly produce non-tumorigenic progeny with very limited self-renewal.

These data indicate that long-term progression of PC is driven by a succession of transiently active TIC generating tumor cells in temporally restricted bursts. The recruitment of inactive TIC clones to tumor formation after serial transplantation points to a context-dependent regulation of TIC activity within the growing tumor. Further understanding the mechanisms regulating the balance between activated and resting states of TIC may allow developing specific treatment strategies targeting this most relevant cell population in PC.

Citation Format: Felix Oppel, Claudia R. Ball, Christopher M. Hoffmann, Sebastian M. Dieter, Taronish D. Dubash, Moritz Koch, Jürgen Weitz, Frank Bergmann, Manfred Schmidt, Ulrich Abel, Christof von Kalle, Hanno Glimm. Succession of transiently active TIC clones drives long-term human pancreatic cancer progression . [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2295. doi:10.1158/1538-7445.AM2013-2295

[Frozen section diagnostics in visceral surgery. Liver, bile ducts and pancreas]

Intraoperative examination of specimens from the liver, bile ducts, gallbladder and pancreas are widely used in routine fresh frozen section diagnostics. The main clinical requests focus on diagnosis of masses of unknown dignity as well as evaluation of surgical margins in oncological resections. In addition, assessment of organ quality for transplantation is also often required.

Chemoradiation in patients with isolated recurrent pancreatic cancer - therapeutical efficacy and probability of re-resection

Background

In the present retrospective analysis we analysed the therapeutic outcome of a set of patients, who were treated with chemoradiation (CRT) for recurrent pancreatic cancer (RPC) in a single institution.

Patients and Methods

Forty-one patients had a history of primary resection for pancreatic cancer. In case of an unresectable recurrency patients were treated with CRT at our institution between 2002 and 2010 with a median dose of 48.4 Gy (range 39.6–54 Gy). Concurrent chemotherapy regimes included Gemcitabine (GEM) in 37/41 patients (90%) and Fluorouracil (FU) or Capecitabine (CAP) in 4/41 patients (10%). Patients were re-evaluated after CRT with computed tomography and/or explorative laparotomy. During re-resection or laparotomy 15 patients received an additional intraoperative radiotherapy (IORT) with a median dose of 15 Gy (range 12–15 Gy). Median age was 65 years (range 39–76 years) and there were 26 male and 15 female patients.

Results

The median overall survival (mOS), local control (LC) and progression-free survival (PFS) were 16.1, 13.8 and 6.9 months respectively for all patients after the first day of CRT. Re-resection was possible in five patients (12%) and a complete remission (CR) as defined by tumor-free biopsy was seen in 6 patients (15%). When re-resection could be achieved after CRT mOS was improved to 28.3 months (n = 5 patients, 95%-CI 10.2 – 46.3 months). Patients receiving IORT had a significantly improved mOS compared to no IORT (p = 0.034). Fifteen patients (37%) experienced a local tumour progression and main site of distant metastasis was the liver (11 patients, 27%).Overall treatment-related toxicity was mild, grade III hematologic toxicity was observed in 11 patients (27%).

Conclusion

In summary we observed a good therapeutic response with mild to moderate toxicity levels for CRT in RPC. Overall survival and PFS were clearly improved in case of induction of a complete remission (tumor-free biopsies) or after achieving a re-resection, thus providing a curative intended therapy even in case of disease recurrence.

The impact of MFG-E8 in chronic pancreatitis: potential for future immunotherapy?

Background

The glycoprotein MFG-E8 mediates phagocytic clearance of apoptotic cells and influences the pathogenesis and progression of inflammatory diseases. MFG-E8 was shown to attenuate the progression of inflammation and to improve survival in septic rats. Accumulating evidence suggests an immunomodulatory link between MFG-E8 and the pro-inflammatory chemokine fractalkine, which may determine the severity of pain, fibrosis, and inflammation in chronic pancreatitis (CP).

Methods

The expression and localization of MFG-E8 was investigated in CP (n = 62), and normal pancreas (NP; n = 34) by QRT-PCR, Western-blot and immunohistochemistry analyses. Results were correlated with mRNA expression of fractalkine, CX3CR1, and with the presence and degree of pain and fibrosis. Human pancreatic stellate cells (hPSCs) were isolated from CP tissues and evaluated for MFG-E8 mRNA expression after fractalkine stimulation.

Results

MFG-E8-mRNA was significantly overexpressed in CP and isolated hPSCs when compared to NP. Western-blot and immunohistochemistry analysis confirmed accumulation of MFG-E8 in CP, with noticeably increased MFG-E8 immunoreactivity in tubular complexes. MFG-E8 expression correlated significantly with fractalkine expression, severe fibrosis, and the presence of pain in CP patients. Stimulation of hPSCs with fractalkine led to a significant increase in MFG-E8 expression.

Conclusions

In the present study, we demonstrated for the first time that MFG-E8 is significantly up-regulated in CP patients and together with fractalkine correlated noticeably with severe fibrosis and the presence of pain. hPSCs overexpress MFG-E8 upon fractalkine stimulation in vitro, which underlines the suggested immunmodulatory link in CP and may be a key mechanism in CP fibrogenesis and pain generation. Taken together, these novel findings suggest that MFG-E8 blockade may be a promising tool for future immunotherapy in CP to attenuate both fibrosis and pain sensation.

Re-resection for isolated local recurrence of pancreatic cancer is feasible, safe, and associated with encouraging survival

BACKGROUND

Local recurrence of pancreatic cancer occurs in 80% of patients within 2 years after potentially curative resections. Around 30% of patients have isolated local recurrence (ILR) without evidence of metastases. In spite of localized disease these patients usually only receive palliative chemotherapy and have a short survival.

PURPOSE

To evaluate the outcome of surgery as part of a multimodal treatment for ILR of pancreatic cancer.

METHODS

All consecutive operations performed for suspected ILR in our institution between October 2001 and October 2009 were identified from a prospective database. Perioperative outcome, survival, and prognostic parameters were assessed.

RESULTS

Of 97 patients with histologically proven recurrence, 57 (59%) had ILR. In 40 (41%) patients surgical exploration revealed metastases distant to the local recurrence. Resection was performed in 41 (72%) patients with ILR, while 16 (28%) ILR were locally unresectable. Morbidity and mortality were 25 and 1.8% after resections and 10 and 0% after explorations, respectively. Median postoperative survival was 16.4 months in ILR versus 9.4 months in metastatic disease (p < 0.0001). In ILR median survival was significantly longer after resection (26.0 months) compared with exploration without resection (10.8 months, p = 0.0104). R0 resection was achieved in 18 patients and resulted in 30.5 months median survival. Presence of metastases, incomplete resection, and high preoperative CA 19-9 serum values were associated with lesser survival.

CONCLUSIONS

Resection for isolated local recurrence of pancreatic cancer is feasible, safe, and associated with favorable survival outcome. This concept warrants further evaluation in other institutions and in randomized controlled trials.

Polymorphonuclear neutrophils promote dyshesion of tumor cells and elastase-mediated degradation of E-cadherin in pancreatic tumors

Pancreatic ductal adenocarcinoma (PDAC) presenting with a micropapillary growth pattern is frequently associated with a prominent neutrophil infiltration into the tumor. The relevance of neutrophil infiltrates for tumor progression, however, is still debated. To gain insight into the role of polymorphonuclear neutrophils (PMNs) in PDAC, we assessed their effect on pancreatic tumor cells grown in vitro as monolayers. Time-lapse video microscopy showed a PMN-induced dyshesion of the tumor cells, and subsequent experiments revealed that this dyshesion was due to PMN elastase-mediated degradation of E-cadherin, an adhesion molecule that mediates the intercellular contact of the tumor cells. E-cadherin degradation by elastase or--(for comparison) down-modulation by specific siRNA, significantly increased the migratory capacity of the pancreatic tumor cells, leading to the hypothesis that PMNs could contribute to the invasive tumor growth. To address this issue, biopsies of patients with PDAC (n = 112) were analyzed. We found that E-cadherin expression correlated negatively with PMN infiltration, compatible with the notion that E-cadherin is cleaved by PMN-derived elastase, which in turn could result in the dispersal of the tumor cells, enhanced migratory capacity and thus invasive tumor growth.

Clinicopathologic characteristics of patients with resected multifocal intraductal papillary mucinous neoplasm of the pancreas

BACKGROUND

Intraductal papillary mucinous neoplasms of the pancreas are defined as mucin-producing neoplasms arising in the main pancreatic duct (main duct type), its major branches (branch duct type), or in both (mixed type). Intraductal papillary mucinous neoplasms of the pancreas can occur as a single collection of cysts or as multifocal lesions. While subtypes of intraductal papillary mucinous neoplasms of the pancreas are well described in literature, little is known about the importance of multifocal intraductal papillary mucinous neoplasms of the pancreas. This study evaluated the clinicopathologic characteristics of patients with surgically resected, multifocal intraductal papillary mucinous neoplasm of the pancreas.

METHODS

Clinicopathologic features and preoperative imaging of patients resected for multifocal intraductal papillary mucinous neoplasm of the pancreas defined as intraductal papillary mucinous neoplasm of the pancreas occurring in more than just 1 area, from January 2004 to July 2010 at the Department of Surgery, University of Heidelberg were analyzed. Preoperative parameters, including number of cysts, cyst size, presence of nodules, and epidemiologic data, were assessed and compared to patients with unifocal intraductal papillary mucinous neoplasms of the pancreas.

RESULTS

Among 287 patients with resected intraductal papillary mucinous neoplasms of the pancreas, 51 patients (17.8%) with multifocal cystic pancreatic lesions were identified by preoperative imaging. The median age of patients with multifocal intraductal papillary mucinous neoplasms of the pancreas was ≥ 68 years (P = .002) compared to patients with unifocal intraductal papillary mucinous neoplasm of the pancreas (median age, 64 years). Thirty-one multifocal intraductal papillary mucinous neoplasms of the pancreas were of mixed type (60.8%), 15 of branch duct type (29.4%), and 5 of main duct type (9.8%). Histologically, 10 multifocal intraductal papillary mucinous neoplasms of the pancreas had low-grade dysplasia (19.6%), 11 had moderate dysplasia (21.6%), 6 had high-grade dysplasia (11.8%), and 24 had invasive carcinoma (47.1%).

CONCLUSION

Most multifocal intraductal papillary mucinous neoplasms of the pancreas involve the main pancreatic duct and synchronously its major side branches (mixed type). Patients with multifocal intraductal papillary mucinous neoplasm of the pancreas present at an older age compared to patients with single cystic pancreatic neoplasm. The risk of harboring malignancy-nearly 60% in the present study-seems to be increased in patients with multifocal intraductal papillary mucinous neoplasms of the pancreas compared to single lesions.

Resection after neoadjuvant therapy for locally advanced, "unresectable" pancreatic cancer

BACKGROUND

For pancreatic cancer, complete macroscopic resection in combination with chemotherapy is the only potentially curative treatment. Many patients present with locally advanced cancers deemed unresectable. We sought to assess the results of exploration after neoadjuvant therapy for locally advanced possibly unresectable pancreatic cancer.

METHODS

From a prospective database, all consecutive patients undergoing operation from October 2001 to December 2009 after neoadjuvant therapy for locally advanced pancreatic cancer were identified. Main criteria for "unresectability" were infiltration of the celiac axis or superior mesenteric artery. Resection rates, perioperative results, and survival were analyzed.

RESULTS

Of 257 patients, 199 (77.4%) had received neoadjuvant chemoradiation, and 58 (22.6%) chemotherapy only. Of 257 patients, 120 (46.7%) underwent successful resection, whereas 137 patients underwent exploration only; 47 (39.2%) multivisceral and 45 (37.5%) vascular resections (12 arterial reconstructions) were performed. There were 6 (5%) ypT0 neoplasms, 36 (30.0%) R0, 61 (50.8%) R1, and 16 (13.3%) R2 resections. The median follow-up of surviving patients (n = 22) was 22 months. Median postoperative survival was greater after resection (12.7 months) than after exploration alone (8.8 months; P < .0001). Median postoperative survival was 24.6 months after R0, 11.9 months after R1, and 8.9 months after R2 resection. The 3-year survival rate after R0 resection was 24%. To determine survival after start of neoadjuvant therapy, 3.7 months (median) have to be added.

CONCLUSION

In locally advanced, unresectable pancreatic cancer, R0/R1 resections can be achieved in up to 40% of patients who undergo operation after neoadjuvant therapy. In these cases, survival rates are similar to those observed for initially resectable pancreatic cancer.

Sequential biphasic changes in claudin1 and claudin4 expression are correlated to colorectal cancer progression and liver metastasis

Terminal progression of colorectal cancer (CRC) culminates in liver metastasis. To identify genes that are involved in the metastatic phenotype, cDNA microarrays were used to analyse mRNA expression profiles of colorectal carcinoma (CC)531 rat colon adenocarcinoma cells for changes related to their homing into the liver. Briefly, CC531 cells were intraportally implanted into the liver of Wag-Rij rats and re-isolated after 3, 6, 9, 14 and 21 days. Compared to control CC531 cells, claudin1 and claudin4 were among the ≥8-fold initially down-regulated genes. The co-culture of tumour cells with isolated rat hepatocytes and Kupffer cells did not induce down-regulation of either claudin1 or 4. When the environment effective on circulating tumour cells was simulated by cell culture conditions favouring their adhesion, only claudin4 showed augmented expression. Knockdown of claudin1 and claudin4 mediated by small interfering RNA caused significantly increased migration and decreased clonogenic growth of tumour cells (P < 0.05), but had no effect on their proliferation. These experimental results were paralleled by increased claudin1 and claudin4 expression in human CRC samples in Union for International Cancer Control (UICC) stages I–III, as evaluated by real-time PCR. Increased claudin4 levels were correlated with significantly reduced overall survival (log-rank test, P= 0.018). Further, significantly (P < 0.05) reduced expression of claudin1 and claudin4 was observed in stage IV and liver metastasis by immunohistochemistry. In conclusion, sequential biphasic changes in claudin1 and claudin4 expression occur during the homing of rat CC531 CRC cells to the liver. This modulation is reflected by significant changes in claudin expression in human primary and metastatic CRC.

Expression and therapeutic relevance of heat-shock protein 90 in pancreatic endocrine tumors

Pancreatic endocrine tumors (PET) represent a heterogenous group of neoplasms. Although surgical resection is considered a safe and effective treatment for many PET, therapeutic options for inoperable and progressive PET are limited. The expression of heat-shock protein (HSP) 90 was investigated in 120 clinically and pathomorphologically well-characterized PET from 84 patients using immunohistochemistry. In addition, in 19 snap-frozen PET and in three healthy pancreatic tissues, we performed immunoblot analyses, and in 15 snap-frozen PET and in three healthy pancreatic tissues, we investigated the expression of HSP90 isoforms by means of semiquantitative RT-PCR. Functional tests were conducted using the human pancreas carcinoid cell line BON and the mouse insulinoma cell line β-TC-3. HSP90 was expressed in 95% of the PET patients. The transcript levels of the HSP90 isoforms HSP90α, HSP90β, glucose-related protein 94, and TNF receptor-associated protein 1 were significantly increased in PET compared with non-neoplastic pancreatic tissues. The treatment of the cell lines BON and β-TC-3 with the HSP90 inhibitors 17-allylamino-17-demethoxygeldanamycin and 17-dimethylaminoethylamino-17-demethoxy-geldanamycin resulted in significant, dose-dependent reduction of cell viability, cell cycle arrest, and increased apoptosis. Furthermore, HSP90 inhibition induced the degradation and inactivation of several oncogenetic HSP90 client proteins in a time- and dose-dependent manner. HSP90 inhibitors increased the therapeutic effects of doxorubicin and 5-fluorucacil in BON and β-TC-3 cells. HSP90 is expressed in the vast majority of PET and its inhibition reveals significant treatment effects in vitro. Thus, HSP90 qualifies as a promising new target.

Long-term in vitro culture of hamster pancreatic β-cells and induction of adenocarcinoma by treatment with N-nitrosobis(2-oxopropyl)amine

OBJECTIVES

Earlier studies indicated that hamster pancreatic ductal adenocarcinoma not only derives from ductal/ductular structures but also from cells within the islet. So far unidentified cells within the islet are responsive to the carcinogenic effect of N-nitrosobis (2-oxopropyl) amine (BOP) forming poorly differentiated ductal adenocarcinoma. However, studies indicated a major role of β-cells during carcinogenesis. To find out, if β-cells are the primary target cells of BOP and if they are capable to form ductal adenocarcinoma after malignant transformation, we established a long-term culture of undifferentiated cells deriving from isolated β-cells and treated them with BOP.

METHODS

Langerhans' islets from pancreata of Syrian golden hamsters were isolated and dispersed into single cells by dispase digestion. Cells were labeled with a highly specific β-cell surface antibody (K14D10) and these K14D10+ cells were extracted from the suspension by paramagnetic Dynabeads. Cells were cultured in vitro and treated with BOP. Untreated cells served as control.

RESULTS

K14D10+ cells formed a monolayer and produced insulin over a period of 28 days in culture. However, with time in culture they became undifferentiated with a higher proliferation rate and after about 60 days in culture BOP treated cells showed anchorage independent growth. These cells autotransplanted s.c. formed a well-differentiated ductal adenocarcinoma.

CONCLUSIONS

Pancreatic β-cells are the primary target of BOP without necessarily being embedded in the compound of the Langerhans' islet. With time in culture, they give rise to undifferentiated cells and after malignant transformation they are able to form ductal adenocarcinoma.

Abstract 984: High-level expression of YAP induces protumorigenic Notch signalling in human hepatocarcinogenesis

The evolutionary conserved Hippo-pathway negatively regulates organ size control by phosphorylation and cytoplasmic retention of the transcriptional co-activator yes-associated protein (YAP). Recent studies demonstrated that deletion of essential Hippo-pathway constituents (e.g., Mst-1/2 and WW45) or overexpression of YAP lead to the development of liver cancer. However, the underlying molecular tumor-supporting mechanisms in carcinogenesis have not been defined so far. Overexpression and nuclear accumulation of YAP in nearly 70% of all human hepatocellular carcinomas (HCC) significantly correlated with tumor cell proliferation and dedifferentiation. In human HCC cell lines, siRNA-mediated inhibition of YAP significantly reduced tumor cell viability, and migration/invasion. Based on transcriptomic profiling approaches, the Notch ligand Jagged-1 (Jag-1) was identified as YAP-dependent target gene in HCC cells and in primary murine hepatocytes of transgenic animals expressing constitutively active YAPS127A. Inhibition of YAP reduced the protein levels of Jag-1, cleaved Notch receptor (NICD), and Hes-1, while YAP overexpression increased the amounts of all factors. As detected for YAP knock down, transfection of gene-specific siRNA targeting Jag-1 diminished HCC cell viability and migration. Overexpression and concomitant inhibition of Jag-1 abolished Hes-1 expression and YAP-induced HCC cell viability. By applying different mutant isoforms of YAP (e.g., YAPS127A and YAP5SA-delta-C - dominant negative isoform), TEAD4 but not TEAD1 was identified as the transcription factor required for YAP-dependent regulation of Jag-1 and Hes-1. Furthermore, the WNT/beta-catenin pathway, a putative inducer of Jag-1, did not influence the YAP-dependent modulation of Jag-1. Knock down experiments revealed Mst-2 and Lats-2 as negative regulators of YAP activity and Jag-1/Hes-1 expression. The amounts of YAP, Jag-1, and Hes-1 transcripts as well as proteins significantly correlated with each other in human HCC tissues. Most importantly, increased concentrations of all factors significantly associated with poor prognosis of HCC patients. These data demonstrate that high-level expression of YAP in HCC cells induces tumor growth and tumor cell dissemination in part through activation of the Jag-1/Notch pathway in a TEAD4-dependent and beta-catenin-independent manner. This regulatory cross-talk between Hippo- and Notch-signalling defines a group of HCC patients with poor overall survival.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 984. doi:1538-7445.AM2012-984

Neoadjuvant chemoradiation with Gemcitabine for locally advanced pancreatic cancer

Introduction

To evaluate efficacy and secondary resectability in patients with locally advanced pancreatic cancer (LAPC) treated with neoadjuvant chemoradiotherapy (CRT).

Patients and methods

A total of 215 patients with locally advanced pancreatic cancer were treated with chemoradiation at a single institution. Radiotherapy was delivered with a median dose of 52.2 Gy in single fractions of 1.8 Gy. Chemotherapy was applied concomitantly as gemcitabine (GEM) at a dose of 300 mg/m² weekly, followed by adjuvant cycles of full-dose GEM (1000 mg/m²). After neoadjuvant CRT restaging was done to evaluate secondary resectability. Overall and disease-free survival were calculated and prognostic factors were estimated.

Results

After CRT a total of 26% of all patients with primary unresectable LAPC were chosen to undergo secondary resection. Tumour free resection margins could be achieved in 39.2% (R0-resection), R1-resections were seen in 41.2%, residual macroscopic tumour in 11.8% (R2) and in 7.8% resection were classified as Rx. Patients with complete resection after CRT showed a significantly increased median overall survival (OS) with 22.1 compared to 11.9 months in non-resected patients. Median OS and disease-free survival (DFS) of all patients were 12.3 and 8.1 months respectively. In most cases the first site of disease progression was systemic with hepatic (52%) and peritoneal (36%) metastases.

Discussion

A high percentage of patients with locally advanced pancreatic cancer can undergo secondary resection after gemcitabine-based chemoradiation and has a relative long-term prognosis after complete resection.

Lack of CCR7 expression is rate limiting for lymphatic spread of pancreatic ductal adenocarcinoma

CCR7 expression on tumor cells promotes lymphatic spread in several malignant tumors. However, a comprehensive characterization of the CCL19/CCL21-CCR7 axis in pancreatic ductal adenocarcinoma (PDAC), which is known for its high rates of lymph-node metastases, is still lacking. CCR7 mRNA and CCR7 protein were found to be expressed in spheroid cultures of all six examined PDAC cell lines. In migration assays, CCR7 expressing PDAC cells showed enhanced migration toward CCL19 and CCL21, the two ligands of CCR7. In an orthotopic nude mouse model, CCR7-transfected PT45P1 cells gave rise to significantly larger tumors and showed a higher frequency of lymph vessel invasion and lymph-node metastases than mock-transfected cells. In an analysis using quantitative real-time PCR, CCR7 showed fourfold overexpression in microdissected PDAC cells compared to normal duct cells. Moderate-to-strong immunohistochemical CCR7 expression, found in 58 of 121 well-characterized human PDACs, correlated with high rates of lymph vessel invasion. Conversely, PDACs completely lacking CCR7 expression showed only low rates of lymph vessel invasion and lymph-node metastases. The evaluation of CCL21 expression by immunofluorescence staining revealed a significant upregulation of CCL21 in peritumoral and intratumoral lymph vessels compared to lymph vessels in disease-free pancreata. In conclusion, our study revealed strong evidence that lack of CCR7 impairs the metastatic potential of PDAC. Lymph vessel invasion by CCR7 expressing PDAC cells may be additionally enhanced by upregulation of CCL21 in tumor-associated lymph vessels, representing a previously unknown factor of lymphatic spread.

Cancer with unknown primary: finding a needle in a hay stack

Detection and resection of small neuroendocrine tumours (NET) is like finding a needle in a hay stack. Use of specific tracers such as (68)Ga-DOTATOC in a PET/CT study has been proven to have a high sensitivity and specificity to cells expressing somatostatin-SSR receptors. The use of (99m)Tc-Octreotide to detect neuroendocrine tumours during surgery is an effective adjunct for therapy. We here present a clinical case of patient with NET where these modalities help in both diagnostic and therapeutic surgery.

MHC class II expression in pancreatic tumors: a link to intratumoral inflammation

Major histocompatibility complex class II antigens (MHC class II) are constitutively expressed by professional antigen presenting cells and present antigenic peptides to specific CD4+ T lymphocytes. MHC class II expression, however, can also be induced on epithelial cells and in a variety of solid tumors. We tested MHC class II expression on tissue samples derived from patients with pancreatic ductal adenocarcinoma (PDAC) and pancreatic endocrine tumors (PET). Immunohistochemistry revealed MHC class II expression in 86 of 112 (76.8%) PDAC samples and in 30 of 43 (70.0%) PET samples. In PDAC and PET, MHC class II expression correlated significantly with severity and activity of intratumoral inflammation, as well as with the infiltration of CD4+ T lymphocytes. High MHC class II expression significantly correlated with a better histological grade of differentiation in PDAC. In vitro MHC class II expression could be induced on PDAC tumor cell lines by interferon-γ. These cells were then able to present the staphylococci enterotoxin B superantigen to T lymphocytes, which resulted in T cell proliferation. Our findings suggest that MHC class II expression on pancreatic tumor cells is induced by the intratumoral inflammatory reaction in pancreatic tumors.