Incidence Of Pancreatic Ductal Adenocarcinoma Research Articles

Abstract A119: Assessment and optimization of electroporation assisted tumoral nanoparticle uptake in a pancreatic adenocarcinoma nude mouse model

Abstract Summary: Pancreatic ductal adenocarcinoma (PDAC) is a particularly lethal form of cancer. In 2012, the incidence of PDAC was 43,920. Five year survival for patients with PDAC was 6%, regardless of staging, making PDAC one of the deadliest forms of cancer. One reason for such dismal prognosis is chemoresistance to the current first-line therapy of choice, gemcitabine. There are multiple factors which contribute to chemoresistance observed in pancreatic cancer. Among them, desmoplasia has been increasingly seen as a significant contributor to chemoresistance in PDAC. To overcome desmoplastic chemoresistance, several novel methods of treatment have been developed. Electroporation is one such novel treatment. High electrical fields are applied to cells to create pores which increase the cell permeability. It has been previously demonstrated that electroporation enhances therapeutic efficacy of anticancer drugs in pancreatic tumor models. Nanoparticle-based drug delivery systems constitute a second novel method to overcome desmoplastic chemoresistance. Due to their intrinsic design advantages, nanoparticles have been shown to increase effectiveness of chemotherapeutic agents, while further reducing or even eliminating side effects. To date, there have been no studies to evaluate the cumulative effect of combining both nanoparticle and electroporation strategies to overcome chemoresistance in PDAC. Objective: Our laboratory conducted preliminary studies using a panc-1 athymic nude mouse model to assess doxorubicin iron oxide nanoparticle uptake as a function of electroporation voltage and timing. Our studies showed that electroporation with iron oxide doxorubicin nanoparticle administration increases nanoparticle uptake in panc-1 cell line athymic nude mouse models of PDAC. Methods: Our experiment first assessed the in vitro uptake of doxorubicin-iron oxide nanoparticles and cell viability in panc-1 cells, to optimized electroporation voltage setting to maximize iron uptake without excessive cell death. 2 million panc-1 cells were placed in 1 ml of DMEM with or without 100 nM of iron oxide doxorubicin nanoparticles. Each plate of cells were individually electroporated at voltages from 0 to 1500. The cells were then incubated for another 24 hours. Cells were trypsonized and evaluated for cell viability and iron uptake by flow cytometry and inductively coupled plasma mass spectrometry, respectively. For our in vivo study, mouse xenograft models were inoculated with 5x106 panc-1 human PDAC cell line into the left and right flank tissues to grow tumors roughly 10 mm in size. Once the tumors reached 10mm, the mice were anesthetized. The mice were then randomized into electroporation-nanoparticle administration timing study limbs ranging from electroporation 12 minutes before nanoparticle administration to electroporation 12 minutes after nanoparticle administration. One hour after the administration of nanoparticles, the mice were euthanized and the tumors were excised. Iron content for each tumor sample was analyzed quantitatively and qualitatively, using ICP-MS and H&E staining with Prussian Blue. Results: From our in vitro study, we found that voltage setting of 400V optimally allowed reversible electroporation without excessive cell death. Our in vivo study demonstrated that electroporation 3 minutes after administration of intravenous nanoparticles provided the greatest degree of intratumoral particle uptake. Conclusions: Significant improvement in chemotherapeutic uptake can be achieved, using optimized nanoparticle and electroporation settings to overcome the intrinsic chemoresistance in PDAC. Citation Format: Derek Lamont West, Sarah White, Zhuoli Zhang, Andrew Larson, Reed Omary. Assessment and optimization of electroporation assisted tumoral nanoparticle uptake in a pancreatic adenocarcinoma nude mouse model. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Innovations in Research and Treatment; May 18-21, 2014; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2015;75(13 Suppl):Abstract nr A119.

Targeting pancreatitis blocks tumor-initiating stem cells and pancreatic cancer progression.

Recent development of genetically engineered mouse models (GEMs) for pancreatic cancer (PC) that recapitulates human disease progression has helped to identify new strategies to delay/inhibit PC development. We first found that expression of the pancreatic tumor-initiating/cancer stem cells (CSC) marker DclK1 occurs in early stage PC and in both early and late pancreatic intraepithelial neoplasia (PanIN) and that it increases as disease progresses in GEM and also in human PC. Genome-wide next generation sequencing of pancreatic ductal adenocarcinoma (PDAC) from GEM mice revealed significantly increased DclK1 along with inflammatory genes. Genetic ablation of cyclo-oxygenase-2 (COX-2) decreased DclK1 in GEM. Induction of inflammation/pancreatitis with cerulein in GEM mice increased DclK1, and the novel dual COX/5-lipoxygenase (5-LOX) inhibitor licofelone reduced it. Dietary licofelone significantly inhibited the incidence of PDAC and carcinoma in situ with significant inhibition of pancreatic CSCs. Licofelone suppressed pancreatic tumor COX-2 and 5-LOX activities and modulated miRNAs characteristic of CSC and inflammation in correlation with PDAC inhibition. These results offer a preclinical proof of concept to target the inflammation initiation to inhibit cancer stem cells early for improving the treatment of pancreatic cancers, with immediate clinical implications for repositioning dual COX/5-LOX inhibitors in human trials for high risk patients.

Pancreatic cancer genomics: where can the science take us?

The incidence of pancreatic ductal adenocarcinoma (PDAC) is steadily increasing and the annual death-to-incidence ratio approaches one. This is a figure that has not changed for several decades. Surgery remains the only chance of cure; however, only less than 20% of patients are amenable to operative resection. Despite successful surgical resection, the majority of the patients still succumb to recurrent metastatic disease. Therefore, there is an urgent need to develop novel therapeutic strategies and to better select patients for current therapies. In this review, we will discuss current management by highlighting the landmark clinical trials that have shaped current care. We will then discuss the challenges of therapeutic development using the current randomized-controlled trial paradigm when confronted with the molecular heterogeneity of PDAC. Finally, we will discuss strategies that may help to shape the management of PDAC in the near future.

Eflornithine (DFMO) prevents progression of pancreatic cancer by modulating ornithine decarboxylase signaling.

Ornithine decarboxylase (ODC) is the key rate-limiting enzyme in the polyamine synthesis pathway and it is overexpressed in a variety of cancers. We found that polyamine synthesis and modulation of ODC signaling occurs at early stages of pancreatic precursor lesions and increases as the tumor progresses in Kras-activated p48(Cre/+)-LSL-Kras(G12D/+) mice. Interest in use of the ODC inhibitor eflornithine (DFMO) as a cancer chemopreventive agent has increased in recent years since ODC was shown to be transactivated by the c-myc oncogene and to cooperate with the ras oncogene in malignant transformation of epithelial tissues. We tested the effects of DFMO on pancreatic intraepithelial neoplasias (PanIN) and their progression to pancreatic ductal adenocarcinoma (PDAC) in genetically engineered Kras mice. The Kras(G12D/+) mice fed DFMO at 0.1% and 0.2% in the diet showed a significant inhibition (P < 0.0001) of PDAC incidence compared with mice fed control diet. Pancreatic tumor weights were decreased by 31% to 43% (P < 0.03-0.001) with both doses of DFMO. DFMO at 0.1% and 0.2% caused a significant suppression (27% and 31%; P < 0.02-0.004) of PanIN 3 lesions (carcinoma in situ). DFMO-treated pancreas exhibited modulated ODC pathway components along with decreased proliferation and increased expression of p21/p27 as compared with pancreatic tissues derived from mice fed control diet. In summary, our preclinical data indicate that DFMO has potential for chemoprevention of pancreatic cancer and should be evaluated in other PDAC models and in combination with other drugs in anticipation of future clinical trials.

Abstract 2969: Combinational Targeting of EGFR and ODC pathways by Gefitinib and DFMO lead to complete blockade of PanIN progression to pancreatic ductal adenocarcinoma

Abstract Pancreatic cancer (PC) is a devastating disease with almost uniform lethality despite aggressive treatment (5-year survival rate of &amp;lt;6%). Developing novel strategies to prevent/delay/inhibit progression of PC is currently of intense interest. Epidermal growth factor receptor (EGFR) is over-expressed in ∼87% human pancreatic cancers and plays a pivotal role in tumor cell proliferation. An interaction between ornithine decarboxylase (ODC) overexpression and EGFR was suggested by the elevation of EGFR Tyr-K activity. Clinical and preclinical studies have clearly demonstrated chemopreventive potential of difloromethyl ornithine (DFMO), an ODC inhibitor. Higher doses of gefitinib (EGFR inhibitor) and DFMO has been associated with skin- and oto-toxicity respectively. Hence, to target EGFR and ODC simultaneously, we tested the effects of lower doses of gefitinib and DFMO individually and in combination on pancreatic intraepithelial neoplasms (PanINs) and their progression to pancreatic ductal adenocarcinoma (PDAC) in p48Cre/+-LSL-KrasG12D/+ transgenic mice. Six-week old male and female KrasG12D/+ (24-34/group) mice were fed (AIN-76A) diets containing 0%, 0.01% gefitinib, 0.1% DFMO or combination of both for 38 weeks. Pancreata were collected, weighed, and evaluated histopathologically for PanINs and PDAC. To understand molecular mechanisms, we analyzed levels of proliferation, apoptosis and cell cycle makers; PCNA, p21, β-catenin, Cav-1, Bcl-XL, c-MYC, cyclin E and pERK expressions by IHC, IHF, Western blotting, and/or RT-PCR methods. Results suggest that control diet fed mice showed 80 and 65% incidence of PDAC in male and female mice, respectively. Dietary gefitinib and DFMO significantly inhibited incidence of PDAC in both male (90 &amp; 87%, respectively, p&amp;lt;0.0001) and female (84 &amp; 75%, respectively, p&amp;lt;0.0001) mice. Most importantly, the combination drug treatment showed complete (100%, p&amp;lt;0.0001) inhibition of PDAC incidence in both genders of mice. Also, significant suppression of PanIN 3 (carcinoma in-situ) was observed in mice fed by gefitinib, DFMO and their combination. Importantly, ∼77% of the pancreas was free from lesions and carcinoma in the combination treatment compared to only 4 % in control and 39 and 23 % in gefitinib and DFMO fed mice respectively. The pancreas of mice fed combination diets showed a significant inhibition of PCNA, β-catenin, Cav-1, Bcl-XL, c-MYC, cyclin E and pERK expression levels (p&amp;lt;0.05-0.001); and increased p21 when compared to the pancreatic cancer derived from control diet or individual drug fed mice. In summary, targeting the EGFR and ODC pathways simultaneously may provide synergistic and/or additive chemopreventive effects in suppression of PC and has significant potential for undertaking clinical trials of pancreatic cancer chemoprevention. {Supported by NCI-CN-N01-53300}. Citation Format: Altaf Mohammed, Naveena B. Janakiram, Rebekah L. Ritchie, Laura Biddick, Misty Brewer, Stan Lightfoot, Vernon E. Steele, Chinthalapally V. Rao. Combinational Targeting of EGFR and ODC pathways by Gefitinib and DFMO lead to complete blockade of PanIN progression to pancreatic ductal adenocarcinoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2969. doi:10.1158/1538-7445.AM2014-2969

Sociodemographic trends in the incidence of pancreatic and biliary tract cancer in UK primary care.

BackgroundThe UK incidence of pancreatic ductal adenocarcinoma (PDAC) is approximately 9/100,000 population compared with 1–2/100,000 for biliary tract cancer (BTC). This study explores the incidence of these cancers over time and the influence of socio-demographic and geographic factors in a UK primary care cohort.MethodsThis study uses data from a large UK primary care database, The Health Improvement Network (THIN). All adult patients contributing data to THIN between January 2000 and December 2010 were included. Annual incidence rates were calculated, adjusted for age, gender, time period, deprivation score (Townsend quintile) and strategic health authority.ResultsFrom 2000–2010, the annual incidence of PDAC increased by an average of 3% per year (95% CI 1.00–4.00%) and BTC by 4% (95% CI 2.00–6.00%). Incidence of both cancers increased steeply with age and was higher in men. BTC was associated with increasing deprivation (most deprived versus least deprived quintile (OR: 1.45 [95% CI: 1.17, 1.79.]).ConclusionsThe overall incidence of both cancers is low but increasing. Variations in incidence may reflect changes in coding practice or increased exposure to associated risk factors.

Assessment and optimization of electroporation-assisted tumoral nanoparticle uptake in a nude mouse model of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a particularly lethal form of cancer. In 2012, the incidence of PDAC was 43,920. Five-year survival for patients with PDAC is around 6%, regardless of staging, making PDAC one of the deadliest forms of cancer. One reason for this dismal prognosis is chemoresistance to the current first-line therapy, gemcitabine. There are multiple factors that contribute to the chemoresistance observed in pancreatic cancer. Among them, desmoplasia has been increasingly seen as a significant contributor to chemoresistance. To overcome desmoplastic chemoresistance, several novel methods of treatment have been developed. Electroporation is one such novel treatment. High electrical fields are applied to cells to create pores that increase cell permeability. It has been previously demonstrated that electroporation enhances the therapeutic efficacy of anticancer drugs in pancreatic tumor models. Nanoparticle-based drug delivery systems constitute a second novel method to overcome desmoplastic chemoresistance. Due to their intrinsic design advantages, nanoparticles have been shown to increase the effectiveness of chemotherapeutic agents, while further reducing or even eliminating side effects. To date, there have been no studies evaluating the cumulative effect of combining both nanoparticle and electroporation strategies to overcome chemoresistance in PDAC. Our preliminary studies assessed the in vitro and in vivo uptake of doxorubicin-loaded iron oxide nanoparticles as a function of electroporation voltage and timing of administration in pancreatic adenocarcinoma cells. Our studies demonstrated that addition of electroporation to administration of nanoparticles significantly increased the amount of intracellular iron oxide nanoparticle uptake by a PANC-1 cell line in an athymic nude mouse model of PDAC. Further, electroporation-assisted nanoparticle uptake could be significantly altered by changing the timing of application of electroporation.

Incidental pancreatic cystic lesions: is there a relationship with the development of pancreatic adenocarcinoma and all-cause mortality?

To establish the effect of incidental pancreatic cysts found by using computed tomographic (CT) and magnetic resonance (MR) imaging on the incidence of pancreatic ductal adenocarcinoma and overall mortality in patients from an inner-city urban U.S. tertiary care medical center. Institutional review board granted approval for the study and waived the informed consent requirement. The study population comprised cyst and no-cyst cohorts drawn from all adults who underwent abdominal CT and/or MR November 1, 2001, to November 1, 2011. Cyst cohort included patients whose CT or MR imaging showed incidental pancreatic cysts; no-cyst cohort was three-to-one frequency matched by age decade, imaging modality, and year of initial study from the pool without reported incidental pancreatic cysts. Patients with pancreatic cancer diagnosed within 5 years before initial CT or MR were excluded. Demographics, study location (outpatient, inpatient, or emergency department), dates of pancreatic adenocarcinoma and death, and modified Charlson scores within 3 months before initial CT or MR examination were extracted from the hospital database. Cox hazard models were constructed; incident pancreatic adenocarcinoma and mortality were outcome events. Adenocarcinomas diagnosed 6 months or longer after initial CT or MR examination were considered incident. There were 2034 patients in cyst cohort (1326 women [65.2%]) and 6018 in no-cyst cohort (3,563 [59.2%] women); respective mean ages were 69.9 years ± 15.1(standard deviation) and 69.3 years ± 15.2, respectively (P = .129). The relationship between mortality and incidental pancreatic cysts varied by age: hazard ratios were 1.40 (95% confidence interval [ CI confidence interval ]: 1.13, 1.73) for patients younger than 65 years and 0.97 (95% CI confidence interval : 0.88, 1.07), adjusted for sex, race, imaging modality, study location, and modified Charlson scores. Incidental pancreatic cysts had a hazard ratio of 3.0 (95% CI confidence interval : 1.32, 6.89) for adenocarcinoma, adjusted for age, sex, and race. Incidental pancreatic cysts found by using CT or MR imaging are associated with increased mortality for patients younger than 65 years and an overall increased risk of pancreatic adenocarcinoma.

NFAT in Pancreatic Carcinogenesis

Pancreatic Ductal Adenocarcinoma (PDAC) belongs to the most aggressive malignancies among solid tumors. The increasing incidence of PDAC and its dismal prognosis with a five-years overall survival rate of less than five percent characterize PDAC as one of the most clinically challenging diseases among all malignancies. In recent years, increasing knowledge about the molecular pathogenesis of PDAC has shown that mutational activation of oncogenic Kras represents the defining event in pancreatic cancer initiation, but full neoplastic pancreatic cancer progression requires dysregulation of additional pathways. In this review we summarize and discuss the impact of inflammation-induced transcription of the of Activates T-cell (NFAT)-family in pancreatic carcinogenesis.

Antidiabetic Drug Metformin Prevents Progression of Pancreatic Cancer by Targeting in Part Cancer Stem Cells and mTOR Signaling

Epidemiologic studies have shown that diabetes mellitus is associated positively with increased risk of pancreatic ductal adenocarcinoma (PDAC), and recent meta-analysis studies showed that metformin, reduces the risk of pancreatic cancer (PC). We tested the effects of metformin on pancreatic intraepithelial neoplasia (PanIN) and their progression to PDAC in p48Cre/+.LSL-KrasG12D/+ transgenic mice. Mice fed control diet showed 80% and 62% incidence of PDAC in males and females, respectively. Male mice showed 20% and 26%, and female mice showed 7% and 0% PDAC incidence with 1000- and 2000-ppm metformin treatments, respectively. Both doses of metformin decreased pancreatic tumor weights by 34% to 49% (P < 0.03–0.001). The drug treatment caused suppression of PanIN 3 (carcinoma in situ) lesions by 28% to 39% (P < .002) and significant inhibition of carcinoma spread in the pancreas. The pancreatic tissue and/or serum of mice fed metformin showed a significant inhibition of mammalian target of rapamycin (mTOR), extracellular signal-regulated kinases (ERK), phosphorylated extracellular signal-regulated kinases (pErk), and insulin-like growth factor 1 (IGF-1) with an increase in phosphorylated 5′ adenosine monophosphate kinase (pAMPK), tuberous sclerosis complex 1 (TSC1, TSC2), C-protein and an autophagy related protein 2 (ATG2). The cancer stem cell (CSC) markers were significantly decreased (P < 0.04–0.0002) in the pancreatic tissue. These results suggest that biologic effects of metformin are mediated through decreased CSC markers cluster of differentiation 44 (CD44 and CD133), aldehyde dehydrogenase isoform 1 (ALDH1), and epithelial cell adhesion molecule (EPCAM) and modulation of the mTOR signaling pathway. Our preclinical data indicate that metformin has significant potential for use in clinical trials for PC chemoprevention.

Sulindac inhibits pancreatic carcinogenesis in LSL-KrasG12D-LSL-Trp53R172H-Pdx-1-Cre mice via suppressing aldo-keto reductase family 1B10 (AKR1B10)

Sulindac has been identified as a competitive inhibitor of aldo-keto reductase 1B10 (AKR1B10), an enzyme that plays a key role in carcinogenesis. AKR1B10 is overexpressed in pancreatic ductal adenocarcinoma (PDAC) and exhibits lipid substrate specificity, especially for farnesyl and geranylgeranyl. There have been no studies though showing that the inhibition of PDAC by sulindac is via inhibition of AKR1B10, particularly the metabolism of farnesyl/geranylgeranyl and Kras protein prenylation. To determine the chemopreventive effects of sulindac on pancreatic carcinogenesis, 5-week-old LSL-Kras(G12D)-LSL-Trp53(R172H)-Pdx-1-Cre mice (Pan(kras/p53) mice) were fed an AIN93M diet with or without 200 p.p.m. sulindac (n = 20/group). Kaplan-Meier survival analysis showed that average animal survival in Pan(kras/p53) mice was 143.7 ± 8.8 days, and average survival with sulindac was increased to 168.0 ± 8.8 days (P < 0.005). Histopathological analyses revealed that 90% of mice developed PDAC, 10% with metastasis to the liver and lymph nodes. With sulindac, the incidence of PDAC was reduced to 56% (P < 0.01) and only one mouse had lymph node metastasis. Immunochemical analysis showed that sulindac significantly decreased Ki-67-labeled cell proliferation and markedly reduced the expression of phosphorylated extracellular signal-regulated kinases 1 and 2 (ERK1/2), c-Raf and mitogen-activated protein kinase kinase 1 and 2. In in vitro experiments with PDAC cells from Pan(kras/p53) mice, sulindac exhibited dose-dependent inhibition of AKR1B10 activity. By silencing AKR1B10 expression through small interfering RNA or by sulindac treatment, these in vitro models showed a reduction in Kras and human DNA-J homolog 2 protein prenylation, and downregulation of phosphorylated C-raf, ERK1/2 and MEK1/2 expression. Our results demonstrate that sulindac inhibits pancreatic carcinogenesis by the inhibition of Kras protein prenylation by targeting AKR1B10.

Abstract 2268: Metformin prevents progression of pancreatic intraepithelial neoplasia to ductal adenocarcinoma by targeting cancer stem cells and mTOR signaling.

Abstract Pancreatic cancer (PC) is one of the most lethal malignancies and a devastating disease almost uniformly lethal with a &amp;lt;6% five year survival. Developing novel strategies to prevent or delay progression of PC is currently of intense interest. Epidemiologic studies show that diabetes mellitus is positively associated with increased risk for PC. Recent meta-analysis showed that metformin, an insulin-lowering agent, reduces risk of PC. Studies have clearly demonstrated that metformin elicits a protective effect by targeting mTOR signaling and tumor-initiating cancer stem cells (TICSC). However, metformin efficacy and systematic analysis of mechanisms have not been evaluated in a preclinical model that recapitulates human PC. We tested the effects of metformin on pancreatic intraepithelial neoplasms (PanINs) and their progression to pancreatic ductal adenocarcinoma (PDAC) in Kras-activated p48Cre/+-LSL-KrasG12D/+ transgenic mice. Six-week old male and female KrasG12D/+ mice (∼35/group) were fed AIN-76A diets containing 0, 1000 and 2000 ppm metformin for 38 weeks. Pancreata were collected, weighed, and evaluated histopathologically for PanINs and PDAC. To evaluate molecular mechanisms, we analyzed modulation of mTOR signaling molecules: mTOR, pAMPK, IRS1, TSC1, TSC2, S6, p70-S6, Rheb, ERK, pERK, ATG2, leptin, IGF1, C-reactive protein and markers of TICSC : ALDH1, CD133, CD24, CD44, EPCAM and DCLK-1 in pancreatic tumors and/or serum by IHC, IHF, Western blotting, and/or real time-PCR. Male and female mice fed control diet had 80 and 62% incidence of PDAC, respectively. Dietary administration of 1000 or 2000 ppm metformin yielded a PDAC incidence of 20 or 26%, respectively, in males (p&amp;lt;0.002-0.0006) and 7 or 0%, respectively, in females (p&amp;lt;0.0004-0.0001).The pancreatic tumor weights were decreased by 34-49% (p&amp;lt;0.03-0.001) with both doses of metformin. Most importantly, metformin caused &amp;gt;95% (p&amp;lt;0.0001) inhibition of carcinoma spread in the pancreas and a significant suppression of PanIN 3 lesions (carcinoma in situ) (28-39%, p&amp;lt;0.002). The pancreatic tissue and/or serum of mice fed metformin showed a significant decrease in mTOR signaling molecules mTOR, S6, p70-S6, Rheb, IGF-1, C-protein, ERK and pERK with an increase in pAMPK, TSC1, TSC2, IRS1 and ATG2. The TICSC markers CD44, CD133, ALDH1 and EPCAM were reduced significantly with an increase in CD24 expression (p&amp;lt;0.04-0.0002). These results suggest that the anti-tumor effects of metformin are mediated through decreased TICSC markers and modulation of the mTOR signaling pathway. These studies with a transgenic mouse model of pancreatic cancer suggest that metformin has significant potential for human chemoprevention trials in individuals at high-risk for pancreatic cancer. {Supported by NCI-CN-N01-53300}. Citation Format: Altaf Mohammed, Misty Brewer, Rebekah L. Ritchie, Anuj Marya, Stan Lightfoot, Naveena B. Janakiram, Vernon E. Steele, Chinthalapally V. Rao. Metformin prevents progression of pancreatic intraepithelial neoplasia to ductal adenocarcinoma by targeting cancer stem cells and mTOR signaling. [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 2268. doi:10.1158/1538-7445.AM2013-2268

Mechanistic Insights into Self-Reinforcing Processes Driving Abnormal Histogenesis During the Development of Pancreatic Cancer

Pancreatic ductal adenocarcinoma, one of the most feared lethal and painful diseases, is increasing in incidence. The poor prognosis of pancreatic ductal adenocarcinoma-affected patients primarily is owing to our inability to develop effective therapies. Mechanistic studies of genetic, epigenetic, and cell-to-cell signaling events are providing clues to molecular pathways that can be targeted in an attempt to cure this disease. The current review article seeks to draw inferences from available mechanistic knowledge to build a theoretical framework that can facilitate these approaches. This conceptual model considers pancreatic cancer as a tissue disease rather than an isolated epithelial cell problem, which develops and progresses in large part as a result of three positive feedback loops: i) genetic and epigenetic changes in epithelial cells modulate their interaction with mesenchymal cells to generate a dynamically changing process of abnormal histogenesis, which drives more changes; ii) the faulty tissue architecture of neoplastic lesions results in unsynchronized secretion of signaling molecules by cells, which generates an environment that is poor in oxygen and nutrients; and iii) the increased metabolic needs of rapidly dividing cells serve as an evolutionary pressure for them to adapt to this adverse microenvironment, leading to the emergence of resistant clones. We discuss how these concepts can guide mechanistic studies, as well as aid in the design of novel experimental therapeutics.

Endogenous n-3 Polyunsaturated Fatty Acids Delay Progression of Pancreatic Ductal Adenocarcinoma in Fat-1-p48Cre/+-LSL-KrasG12D/+ Mice

Preclinical studies suggest that diets rich in omega-3 polyunsaturated fatty acids (n-3 PUFAs) may be beneficial for prevention of pancreatic cancer. Nutritional intervention studies are often complex, and there is no clear evidence, without potential confounding factors, on whether conversion of n-6 PUFAs to n-3 PUFAs in pancreatic tissues would provide protection. Experiments were designed using n-3 fatty acid desaturase (Fat-1) transgenic mice, which can convert n-6 PUFA to n-3 FAs endogenously, to determine the impact of n-3 PUFAs on pancreatic intraepithelial neoplasms (PanINs) and their progression to pancreatic ductal adenocarcinoma (PDAC). Six-week-old female p48(Cre/+)-LSL-Kras(G12D/+) and compound Fat-1-p48(Cre/+)-LSL-Kras(G12D/+) mice were fed (AIN-76A) diets containing 10% safflower oil for 35 weeks. Pancreata were evaluated histopathologically for PanINs and PDAC. Results showed a dramatic reduction in incidence of PDAC (84%; P < .02) in Fat-1-p48(Cre/+)-LSL-Kras(G12D/+) mice compared to p48(Cre/+)-LSL-Kras(G12D/+) mice. Importantly, significant reductions of pancreatic ducts with carcinoma (90%; P < .0001) and PanIN 3 (~50%; P < .001) lesions were observed in the compound transgenic mice. The levels of n-3 PUFA were much higher (>85%; P < .05-0.01) in pancreas of compound transgenic mice than in those of p48(Cre/+)-LSL-Kras(G12D/+) mice. Molecular analysis of the pancreas showed a significant down-regulation of proliferating cell nuclear antigen, cyclooxygenase-2, 5-lipoxygenase (5-LOX), 5-LOX-activating protein, Bcl-2, and cyclin D1 expression levels in Fat-1-p48(Cre/+)-LSL-Kras(G12D/+) mice compared to p48(Cre/+)-LSL-Kras(G12D/+) mice. These data highlight the promise of dietary n-3 FAs for chemoprevention of pancreatic cancer in high-risk individuals.

Abstract B115: Eflornithine (DFMO) Prevents Progression of Pancreatic Intraepithelial Neoplasia to Ductal Adenocarcinoma in LSL-KrasG12D/+ Mice

Abstract Pancreatic cancer still remains a devastating disease almost uniformly lethal with a &amp;lt;6% five year survival, despite tremendous scientific efforts for over three decades. Developing novel strategies to prevent or delay progression of pancreatic cancer is currently of intense interest. Clinical and preclinical studies have clearly demonstrated eflornithine (DFMO) as a potential chemopreventive agent for several cancers. However, efficacy of DFMO in a preclinical model that recapitulates human pancreatic cancer has not yet been evaluated. The rationale for the use of DFMO as a cancer chemopreventive agent has been strengthened in recent years because ODC has been shown to be transactivated by the c-myc oncogene in cell/tissue types and to cooperate with the ras oncogene in malignant transformation of epithelial tissues. In the present study, we tested the effects of eflornithine on pancreatic intraepithelial neoplasms (PanINs) and their progression to pancreatic ductal adenocarcinoma (PDAC) in Kras activated p48Cre/+-LSL-KrasG12D/+ transgenic mice. Six-week old male and female KrasG12D/+ (∼35/group) mice were fed (AIN-76A) diets containing 0, 1000 and 2000 ppm DFMO for 38 weeks. No significant body weight differences were observed within the treatment groups. Pancreata were collected, weighed, and evaluated histopathologically for PanINs and PDAC. To understand molecular mechanisms, we analyzed levels of proliferation, apoptosis and cell cycle makers; PCNA, p21, cyclin E, Bcl-xl, c-myc, caveolin-1, cyclin D1 and β-catenin by IHC, Western blotting, and/or RT-PCR methods. Results suggests that control diet fed mice showed 85 and 65% incidence of PDAC in male and female mice, respectively. Whereas 1000 ppm DFMO diet fed mice showed 10% (male) and 16% (female) incidence of PDAC respectively; and, 2000 ppm DFMO diet fed mice showed 6% (male) and 9% (female) incidence of PDAC respectively. The pancreatic tumor weights were decreased by 31-43% (p&amp;lt;0.03-0.001) with both doses of DFMO in male and female mice. Most importantly, the drug treatment showed &amp;gt;95% (p&amp;lt;0.07-0.0006) inhibition of carcinoma spread in the pancreas. Also, a significant dose dependent suppression of PanIN 3 lesions (carcinoma in-situ) (27 and 31% P&amp;lt;0.04 in male; 21 and 33% in female) was observed in mice fed with DFMO at 1000 and 2000 ppm, respectively. The pancreas of mice fed DFMO diets showed a significant inhibition of PCNA, cyclin D1, β-catenin, cyclin E, Bcl-xl, c-myc, cavolin-1 expression levels (p&amp;lt;0.05-0.0002); and increased p21 and apoptosis, when compared to the pancreatic cancer tissues derived from control diet fed mice. In summary, our preclinical data clearly indicate that DFMO has significant potential for undertaking clinical trials of pancreatic cancer chemoprevention. {Supported by NCI-CN-N01-53300}. Citation Format: Altaf Mohammed, Naveena B. Janakiram, Misty Brewer, Rebekah L. Ritchie, Anuj Marya, Stan Lightfoot, Vernon E. Steele, Chinthalapally V. Rao. Eflornithine (DFMO) prevents progression of pancreatic intraepithelial neoplasia to ductal adenocarcinoma in LSL-KrasG12D/+ mice. [abstract]. In: Proceedings of the Eleventh Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2012 Oct 16-19; Anaheim, CA. Philadelphia (PA): AACR; Cancer Prev Res 2012;5(11 Suppl):Abstract nr B115.

Inhibition of Pancreatic Intraepithelial Neoplasia Progression to Carcinoma by Nitric Oxide-Releasing Aspirin in p48Cre/+-LSL-KrasG12D/+ Mice

Nitric oxide-releasing aspirin (NO-aspirin) represents a novel class of promising chemopreventive agents. Unlike conventional nonsteroidal anti-inflammatory drugs, NO-aspirin seems to be free of adverse effects while retaining the beneficial activities of its parent compound. The effect of NO-aspirin on pancreatic carcinogenesis was investigated by assessing the development of precursor pancreatic lesions and adenocarcinomas in KrasG12D/+ transgenic mice that recapitulate human pancreatic cancer progression. Six-week-old male p48Cre/+-LSL-KrasG12D/+ transgenic mice (20 per group) were fed diets containing 0, 1000, or 2000 ppm NO-aspirin. The development of pancreatic tumors was monitored by positron emission tomography imaging. All mice were killed at the age of 41 weeks and assessed for pancreatic intraepithelial neoplasia (PanIN) and pancreatic ductal adenocarcinoma (PDAC) and for molecular changes in the tumors. Our results reveal that NO-aspirin at 1000 and 2000 ppm significantly suppressed pancreatic tumor weights, PDAC incidence, and carcinoma in situ (PanIN-3 lesions). The degree of inhibition of PanIN-3 and carcinoma was more pronounced with NO-aspirin at 1000 ppm (58.8% and 48%, respectively) than with 2000 ppm (47% and 20%, respectively). NO-aspirin at 1000 ppm significantly inhibited the spread of carcinoma in the pancreas (∼97%; P < .0001). Decreased expression of cyclooxygenase (COX; with ∼42% inhibition of total COX activity), inducible nitric oxide synthase, proliferating cell nuclear antigen, Bcl-2, cyclin D1, and β-catenin was observed, with induction of p21, p38, and p53 in the pancreas of NO-aspirin-treated mice. These results suggest that low-dose NO-aspirin possesses inhibitory activity against pancreatic carcinogenesis by modulating multiple molecular targets.

Mo1210 Incidence of Pancreatic Ductal Adenocarcinoma and Extrapancreatic Malignancy in Patients With Branch Duct Intraductal Papillary Mucinous Neoplasm of the Pancreas

Mo1210 Incidence of Pancreatic Ductal Adenocarcinoma and Extrapancreatic Malignancy in Patients With Branch Duct Intraductal Papillary Mucinous Neoplasm of the Pancreas

Atorvastatin delays progression of pancreatic lesions to carcinoma by regulating PI3/AKT signaling in p48Cre/+ LSL-KrasG12D/+ mice.

Pancreatic cancer is the one of most common causes of cancer deaths and has the worst prognosis. Clinical observational studies suggest that statins may reduce the risk of pancreatic cancer. The chemopreventive efficacy of the statin atorvastatin (Lipitor(®)) and the role of the phosphatidyl-inositol 3-kinase (PI3/AKT) signaling pathway were evaluated for the progression of pancreatic intraepithelial neoplasms (PanINs) to pancreatic ductal adenocarcinoma (PDAC) in conditional p48(Cre/+) -LSL-Kras(G12D/+) transgenic mice. Six-week-old male p48(Cre/+) -LSL-Kras(G12D/+) (20/group) mice were fed AIN-76A diets containing 0, 200 and 400 ppm atorvastatin for 35 weeks. At termination, pancreata were evaluated histopathologically for PanINs and PDAC, and for various PI3/AKT signaling markers, and inflammatory cytokines, by immunohistochemistry/immunohistoflourscence, ELISA, Western blotting and/or reverse transcription-PCR methods. Control diet-fed mice showed 85% incidence of PDAC; whereas, mice fed with atorvastatin showed PDAC incidence of 65 and 35%, respectively (p < 0.0001). Similarly, significant suppression of PanIN-3 (22.6%) was observed in mice fed 400 ppm atorvastatin. Importantly, pancreata from atorvastatin-treated mice were ∼68% free from ductal lesions. Furthermore, pancreas of mice administered with atorvastatin had significantly reduced expressions levels of PCNA, p2X7, p-ERK, RhoA, cyclin D1, survivin, Akt, pAKT, β-catenin, cyclin E, cdK2 and caveolin-1. Also, atorvastatin-treated mice had shown dose-dependent suppression of inflammatory cytokines and a significant increase in tunnel-positive cells, p21 and PARP expression levels in pancreas. Atorvastatin significantly delays the progression of PanIN-1 and -2 lesions to PanIN-3 and PDAC by modulating PI3/AKT signal molecules in a preclinical model, suggesting potential clinical benefits of statins for high-risk pancreatic cancer patients.

Development of Pancreatic Ductal Adenocarcinoma Associated with Intraductal Papillary Mucinous Neoplasia

We retrospectively investigated the incidence of pancreatic ductal adenocarcinoma among patients with intraductal papillary mucinous neoplasms of the pancreas. Based on imaging in 195 such patients, we chose surgery as initial treatment for 54, and periodic evaluation over 6 to 192 months (mean, 52) for 141. In 6 of the 141 patients observed for intraductal papillary mucinous neoplasm (4.2%), pancreatic ductal adenocarcinoma developed. Further, careful monitoring for cancer occurrence in the remnant pancreas proved essential in the surgical resection group; 2 of 26 patients (7.7%) subsequently developed pancreatic ductal adenocarcinoma in the remnant pancreas, at 41 months and 137 months after surgery. Serial observation of patients with intraductal papillary mucinous neoplasms by contrast-enhanced computed tomography or magnetic resonance cholangiopancreatography therefore is critical, whether or not surgical treatment initially was performed.

Abstract A111: Endogenous conversion of n-6 PUFAs to n-3 PUFAs prevents progression of K-Ras activated pancreatic lesion development to pancreatic ductal carcinoma in Fat-1 transgenic mice

Abstract Developing novel strategies to prevent or delay the progression of pancreatic ductal adenocarcinoma (PDAC), a devastating disease with a dismal 5-year survival rate (&amp;lt;5%), is of utmost importance. Preclinical studies suggest that omega-3 fatty acid (n-3 PUFA)-rich diets may be beneficial for pancreatic cancer prevention. Nutritional intervention studies are often complex and there is no clear evidence whether conversion of n-6 PUFAs to n-3 PUFAs in pancreatic tissues would provide protection without potential confounding factors of interference. Thus, experiments were designed using fat-1 transgenic (n-3 fatty acid desaturase) mice, which can convert n-6 PUFA to n-3 PUFA endogenously, to determine the impact of n-3 PUFAs on pancreatic intraepithelial neoplasms (PanINs) and their progression to PDAC. LSL-KrasG12D/+ and p48Cre/+ mice were bred with Fat-1 mice and offspring of activated p48Cre/+-LSL-KrasG12D/+ and Fat-1-p48Cre/+-LSL-KrasG12D/+ were generated. Six-week old transgenic mice p48Cre/+-LSL-KrasG12D/+ (12/group), Fat-1-p48Cre/+-LSL-KrasG12D/+ (12/group), and wild-type (12/group) mice were fed (AIN-76A) a diet containing 10% safflower oil for 35 weeks. Pancreata were collected, weighed, and evaluated histopathologically for PanINs and PDAC. To understand the mechanisms, we analyzed levels of fatty acids and assessed the proliferation, apoptosis, and cell cycle markers by GC, IHC, IHF, Western blotting, Real time and/or RT-PCR. Results show a dramatic reduction in incidence of PDAC (85.8% p&amp;lt;0.02) in Fat-1-p48Cre/+-LSL-KrasG12D/+ mice compared to p48Cre/+-LSL-KrasG12D/+ mice. Importantly, significant reduction of pancreatic ducts with carcinoma (90%, p&amp;lt; 0.0001) and a significant suppression of PanIN 3 (∼50%; p&amp;lt;0.001) were observed in Fat-1-p48Cre/+-LSL-KrasG12D/+ transgenic mice. The levels of n-3 PUFA, -Linoleic acid, DPA and DHA were much higher (∼90%) in pancreatic tissues of Fat-1-p48Cre/+-LSL-KrasG12D/+ mice than that of p48Cre/+-LSL-KrasG12D/+ and WT animals. Importantly, molecular analysis of pancreas showed a significant down-regulation of fatty acid synthase, insulin receptor, insulin receptor substrate-1, PCNA, COX-2, 5-LOX, FLAP, Bcl-2, and cyclin D1 expression levels in Fat-1-p48Cre/+-LSL-KrasG12D/+ mice compared to p48Cre/+-LSL-KrasG12D/+. These data highlight the potential for use of n-3 fatty acids for chemoprevention of pancreatic cancer and represent an important strategy to delay/prevent pancreatic cancer in high-risk individuals. {Supported by Kerley-Cade Chair Endowment for Cancer Research} Citation Information: Cancer Prev Res 2011;4(10 Suppl):A111.