Prevention Of Pancreatic Cancer Research Articles

AB028. S028. Risk of the serous cystic neoplasms in pancreas results from no surgical intervention: a multi-center retrospective study

Background: Serous cystic neoplasms (SCN) of the pancreas are known as no malignant potential, so accurate diagnosis of SCN is significant for pancreatic cancer early detection and prevention as well as avoidance of unnecessary surgeries. However, the faults of preoperative diagnosis may highly increase the risk of carcinogenesis.

Obesity and Pancreatic Cancer: Overview of Epidemiology and Potential Prevention by Weight Loss.

Currently, there are no effective preventive strategies for pancreatic cancer. Obesity has been increasingly recognized as a strong but modifiable risk factor of pancreatic cancer. In this article, we aim to review the literature regarding weight loss on prevention of pancreatic cancer. Epidemiological and laboratory studies have shown that obesity is associated with increased incidence of pancreatic cancer and potentially worse cancer outcome. Whereas the underlying pathomechanisms remain unclear, chronic inflammation, insulin resistance, and altered intestinal microbiota are all implicated in the carcinogenic effect of obesity. Weight loss, especially the durable and significant weight loss after bariatric surgery, has been shown to reduce the risks of multiple cancers and may become a good intervention for pancreatic cancer prevention.

Prevention and Early Detection of Pancreatic Cancer.

Preventing cancer has much to offer. Aside from plummeting health care costs, we might enjoy a healthier life free of cancer and chronic disease. Prevention requires the adoption of healthier choices and a moderate amount of exercise. The supporting evidence is observational, clinical, and partly common sense. Further investigations reveal several substances in a whole-food plant-based diet that have protective effects and an inhibitory effect on tumor development. For pancreatic cancer, the basis of cure remains a century old operation that rarely cures. With little to lose, prevention deserves center stage and additional studies.

Notch signaling molecule is involved in the invasion of MiaPaCa2 cells induced by CoCl2 via regulating epithelial‑mesenchymal transition.

Pancreatic cancer exhibits a high mortality rate resulting from metastasis and there is currently no effective treatment strategy. Hypoxia serves an important role in cancer cells, where cellular metabolic rate is high. The underlying mechanisms that trigger hypoxia and the invasion of pancreatic cancer cells remain unknown. Investigation of the importance of hypoxia in the invasion of pancreatic cancer cells for potential, novel treatment strategies is of primary concern. Cell Counting Kit-8 assay, invasion assay, western blotting and reverse transcription-quantitative polymerase chain reaction were used to investigate invasion and epithelial mesenchymal transition (EMT) and the expression of Notch1 in MiaPaCa2 cells treated with cobalt II chloride (CoCl2). Hypoxia-inducible factor 1α (HIF-1α) small interfering (si)RNA and Notch1 inhibitor N-[N-(3,5-Difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT) were also selected to investigate these mechanisms. Data indicated that CoCl2 increased the invasion ability and altered EMT in MiaPaCa2 cells. CoCl2 regulated the expression of HIF-1α and Notch1 in MiaPaCa2 cells. In addition, HIF-1α siRNA inhibited the effects of CoCl2 on the expression of Notch1 and decreased Snail, EMT and invasion in MiaPaCa2 cells. DAPT increased the expression of epithelial-cadherin and decreased the content of neural-cadherin, Snail and invasion in MiaPaCa2 cells in the presence or absence of CoCl2. CoCl2 promoted invasion by stimulating the expression of HIF-1α and regulating the expression of Notch1 and EMT in MiaPaCa2 cells. Targeting the Notch1 signaling molecule may be a novel treatment strategy for the prevention and treatment of pancreatic cancer.

Sanguinarine inhibits pancreatic cancer stem cell characteristics by inducing oxidative stress and suppressing sonic hedgehog-Gli-Nanog pathway.

Sonic hedgehog pathway is highly activated in pancreatic cancer stem cells (CSC) which play crucial roles in cancer initiation, progression and metastasis. However, the molecular mechanisms by which sanguinarine regulates pancreatic CSC characteristics is not well understood. The objectives of this study were to examine the molecular mechanisms by which sanguinarine regulates pancreatic CSC characteristics. Sanguinarine inhibited cell proliferation and colony formation and induced apoptosis through oxidative damage. Sanguinarine inhibited self-renewal capacity of pancreatic CSCs isolated from human and KrasG12D mice. Furthermore, sanguinarine suppressed epithelial-mesenchymal transition (EMT) by up-regulating E-cadherin and inhibiting N-cadherin. Significant decrease in expression level of Snail, Slug and Zeb1 corroborated the suppression of EMT in sanguinarine treated pancreatic CSCS. The ability of sanguinarine to inhibit pluripotency maintaining factors and CSC markers suggest that sanguinarine can be an effective agent for inhibiting pancreatic cancer growth and development by targeting CSCs. Furthermore, sanguinarine inhibited Shh-Gli pathway leading to modulation of Gli target genes in pancreatic CSCs. Chromatin immunoprecipitation assay demonstrated that Nanog directly binds to promoters of Cdk2, Cdk6, FGF4, c-Myc and Oct4, and sanguinarine inhibits the binding of Nanog with these genes, suggesting the direct involvement of Nanog in cell cycle, pluripotency and self-renewal. To further investigate the role of Shh-Gli-Nanog pathway, we regulated Shh signaling either by Shh protein or Nanog overexpression. Enforced activation of Shh or overexpression of Nanog counteracted the inhibitory effects of sanguinarine on pancreatic CSC proliferation, suggesting the actions of sanguinarine are mediated, at least in part, through Shh-Gli-Nanog pathway. Our studies suggest that sanguinarine can be used for the treatment and/or prevention of pancreatic cancer by targeting CSCs.

Crucial microRNAs and genes in metformin's anti-pancreatic cancer effect explored by microRNA-mRNA integrated analysis.

Despite great improvements in surgical procedures and chemotherapy, pancreatic cancer remains one of the most aggressive and fatal human malignancies, with a low 5-year survival rate. Therefore, novel therapeutic strategies for the prevention and treatment of pancreatic cancer are urgently needed. The present study aimed to investigate the mechanisms by which metformin exerts its anticancer effects on the microRNA-mRNA interactions in human pancreatic cancer. Microarray and systematic analyses revealed that the anti-pancreatic cancer effects of metformin were correlated with 3 up-regulated microRNAs and 4 of their target mRNAs. In addition, the microarray and systematic analyses ultimately demonstrated that 3 microRNAs regulated 4 key mRNAs in a sub-pathway of pancreatic cancer and then affected growth, angiogenesis, and apoptosis. This finding may provide a deeper understanding of the mechanisms by which metformin suppresses proliferation and angiogenesis and promotes apoptosis in pancreatic cancer cells. Collectively, this experiment improves the understanding of the mechanisms by which metformin suppresses pancreatic cancer and indicates that metformin, the most commonly used drug for the treatment of diabetes mellitus, may be a promising candidate agent for the treatment of pancreatic cancer.

Pancreatic Cysts - Part 2: Should We Be Less Cyst Centric?

The management of pancreatic cysts is a common problem faced by physicians and surgeons. Pancreatic cysts are important because some of them are mucin-producing cysts (MPCs), which may harbor or develop pancreatic ductal adenocarcinoma. Thus, accurate classification of pancreatic cysts and diagnosis of MPCs offer a potential for the prevention or early detection of pancreatic cancer. However, the diagnosis and management of asymptomatic pancreatic cysts are complicated by 2 factors. First, incidentally detected pancreatic cysts are often misdiagnosed as branch duct intraductal papillary mucinous neoplasms. Although most are MPCs, there are other types of cysts, such as serous cystadenomas, which are managed differently. Second, only a minority of MPCs will ultimately develop into invasive pancreatic ductal adenocarcinoma. Thus, on the one hand, pancreatic cysts offer a unique opportunity to identify precursors to pancreatic cancer and improve outcomes. On the other hand, misdiagnosis and overzealous testing or unnecessary surgery may lead to high cost and harm to patients. Several guidelines have been developed by various groups for the management of pancreatic cysts. In this article, we review the strengths and weaknesses of the American Gastroenterology Association guidelines, highlight key recommendations requiring further validation, and provide our balanced approach to diagnosing and managing pancreatic cysts.

Targeting reactive nitrogen species suppresses hereditary pancreatic cancer

Germline mutation of BRCA2 induces hereditary pancreatic cancer. However, how BRCA2 mutation specifically induces pancreatic tumorigenesis remains elusive. Here, we have examined a mouse model of Brca2-deficiency-induced pancreatic tumors and found that excessive reactive nitrogen species (RNS), such as nitrite, are generated in precancerous pancreases, which induce massive DNA damage, including DNA double-strand breaks. RNS-induced DNA lesions cause genomic instability in the absence of Brca2. Moreover, with the treatment of antioxidant tempol to suppress RNS, not only are DNA lesions significantly reduced, but also the onset of pancreatic cancer is delayed. Thus, this study demonstrates that excess RNS are a nongenetic driving force for Brca2-deficiency-induced pancreatic tumors. Suppression of RNS could be an important strategy for pancreatic cancer prevention.

Pancreatic Cyst Fluid Vascular Endothelial Growth Factor A and Carcinoembryonic Antigen: A Highly Accurate Test for the Diagnosis of Serous Cystic Neoplasm

Accurate differentiation of pancreatic cystic lesions is important for pancreatic cancer early detection and prevention as well as avoidance of unnecessary surgical intervention. Serous cystic neoplasms (SCN) have no malignant potential, but may mimic premalignant mucinous cystic lesions: mucinous cystic neoplasm (MCN) and intraductal papillary mucinous neoplasm (IPMN). We recently identified vascular endothelial growth factor (VEGF)-A as a novel pancreatic fluid biomarker for SCN. We hypothesize that combining cyst fluid carcinoembryonic antigen (CEA) with VEGF-A will improve the diagnostic accuracy of VEGF-A. Pancreatic cyst/duct fluid was collected from consenting patients undergoing surgical cyst resection with corresponding pathologic diagnoses. Pancreatic fluid VEGF-A and CEA levels were detected by ELISA. One hundred forty-nine patients with pancreatic cystic lesions met inclusion criteria. Pathologic diagnoses included pseudocyst (n=14), SCN (n=26), MCN (n=40), low/moderate grade IPMN (n=34), high grade IPMN (n=20), invasive IPMN (n=10) and solid pseudopapillary neoplasm (n=5). VEGF-A was significantly elevated in SCN cyst fluid compared to all other diagnoses (p<0.001). With a threshold of >5,000 pg/ml, VEGF-A alone has 100% sensitivity and 83.7% specificity to distinguish SCN from other cystic lesions. With a threshold of ≤10ng/ml, CEA alone identifies SCN with 95.5% sensitivity and 81.5% specificity. Sensitivity and specificity of the VEGF-A/CEA combination are 95.5% and 100% respectively. The c-statistic increased from 0.98 to 0.99 when CEA was added to VEGF-A alone in the ROC analysis. Although VEGF-A alone is a highly accurate test for SCN, the combination of VEGF-A with CEA approaches the gold-standard of pathologic diagnosis, thus importantly avoiding false positives. Patients with a positive test indicating benign SCN can be spared a high risk surgical pancreatic resection.

Anti-tumor effects of a ‘human & mouse cross-reactive’ anti-ADAM17 antibody in a pancreatic cancer model in vivo

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal types of tumor amongst all human cancers due to late diagnosis and resistant to treatment with chemotherapy and radiation. Preclinical and clinical studies have revealed that ErbB family for example epidermal growth factor receptor (EGFR) is a validated molecular target for pancreatic cancer prevention and therapy. The ErbB signaling cascade is regulated by a member of the ADAM (a disintegrin and metalloprotease) family, namely ADAM17, by enzymatic cleavage of precursor ligands into soluble cytokines and growth factors. Mouse genetic studies have demonstrated that ADAM17 is required for PDAC development. In this study, we evaluated the anti-tumor effects of A9(B8) IgG – the first specific ‘human and mouse cross-reactive’ ADAM17 inhibitory antibody on pancreatic malignant transformation. We found that inhibition of ADAM17 with A9(B8) IgG efficiently suppressed the shedding of ADAM17 substrates both in vivo and in vitro. Furthermore, we demonstrated that administration of A9(B8) IgG significantly suppressed motility in human pancreatic cancer cells and also significantly delayed tumorigenesis in the Pdx1Cre;KrasG12D;Trp53fl/+PDAC mouse model. Inhibition of ADAM17 with A9(B8) IgG particularly affected the progression of pre-invasive pancreatic lesions to advanced PDAC in mice. Taken together, the preclinical data presented here will provide a starting point for clinical applications of ADAM17 targeted therapy.

Metformin is associated with survival benefit in pancreatic cancer patients with diabetes: a systematic review and meta-analysis.

BackgroundPancreatic cancer is a highly lethal disease with a poor prognosis while metformin has been associated with a decreased risk of pancreatic cancer. Although the benefit of metformin was observed for pancreatic cancer prevention, it is not clear whether it can also affect the survival of pancreatic cancer patients with type 2 diabetes mellitus. A systematic review and meta-analysis was conducted to assess the effect of metformin on the survival of pancreatic cancer patients with type 2 diabetes mellitus.MethodsTwo independent authors searched PubMed and Web of science up to 08/07/2016. We assessed studies for eligibility, extracted data, and examined their quality, with the primary outcome as overall survival. We used published hazard ratio (HR) available or estimated based on other survival data. We pooled the data and used a random-effect model to combine direct comparisons from included articles. We also investigated treatment effects by different countries, quality and the time of metformin initiation.RESULTSWe found that there was a relative survival benefit associated with metformin treatment compared with non-metformin treatment in both overall survival (OS) ([HR] 0.84; 95% confidence interval [CI]: 0.73 – 0.96). These associations were also observed in subgroups of Asian countries and high quality articles.ConclusionsOur results support the notion that metformin maybe the best anti-diabetic medicine of choice in patients with pancreatic cancer and concurrent type 2 diabetes mellitus. The perspectives of enhancing survival of pancreatic cancer patients with diabetes mellitus by the use of metformin deserve more attention in future research and clinical practice.

Prevention of pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDA) accounts for 95% of all pancreatic cancers. About 230,000 PDA cases are diagnosed worldwide each year. PDA has the lowest five-year survival rate as compared to others cancers. PDA in Poland is the fifth leading cause of death after lung, stomach, colon and breast cancer.In our paper we have analysed the newest epidemiological research, some of it controversial, to establish the best practical solution for pancreatic cancer prevention in the healthy population as well as treatment for patients already diagnosed with pancreatic cancer.We found that PDA occurs quite frequently but is usually diagnosed too late, at its advanced stage. Screening for PDA is not very well defined except in subgroups of high-risk individuals with genetic disorders or with chronic pancreatitis.We present convincing, probable, and suggestive risk factors associated with pancreatic cancer, many of which are modifiable and should be introduced and implemented in our society.

Abstract A76: Influence of IL-17-secreting immune cells on pancreatic cancer stemness

Abstract Little is known about how the immune system influences pancreatic cancer stemness. Using a murine model of pancreatic intraepithelial neoplasia (PanIN), we have previously reported that KrasG12D induces expression of IL-17 receptors (IL-17RA) on emerging PanINs, as well as pancreatic infiltration by IL-17-producing CD4+ and gamma-delta-T cells. Forced IL-17 over-expression dramatically accelerates PanIN initiation and progression, while inhibition of IL-17 signaling using either genetic or pharmacologic techniques effectively prevents PanIN formation. When IL-17 signaling was blocked using monoclonal antibodies on transgenic mice harboring PanINs, transcriptional analysis of Kras-mutated epithelial cells revealed significant down-regulation of multiple stemness-related genes: doublecortin-like kinase 1 (Dclk1) [2], Trefoil factor 1 (Tff1)[3], Sonic Hedgehog (SHH) [4], and others. Dclk1 has been recently described as a marker of tumor initiating cells and its functional role in cancer initiation and development is currently being studied. We found that adenovirus mediated-IL-17 overexpression in the murine pancreas harvesting Kras mutation results in PanINs with significantly higher number of Dclk1+ cells that PanINs generated in the presence of a luciferase control virus. Reversely, the genetic ablation of IL-17 in the hematopoietic compartment of the same type of mice resulted in PanINs with significantly lower number of Dclk1+ cells when compared with PanINs from mice transplanted with wild type (WT) bone marrow. We have found that in vitro stimulation of KPC cells (obtained from KrasG12D/+; LSL- Trp53R172H/+; Pdx1Cre mice) with IL-17A results in direct induction of Dclk1, Aldh1 and SHH protein expression in a time-dependent and dose-dependent fashion, validating the results of our gene microarray in a different system and at the protein level. Furthermore, we have found that one of the mechanisms by which IL-17 induces Dclk-1 and ALDH1a1 is through activation of NF-KB canonical pathway. We found that IL-17 had no effect in KPC cells proliferation in 2D culture. However, in vitro stimulation of KPC cells with IL-17A resulted in a significant increase in tumorspheres formation. Even more important, KPC cells in vitro incubated with IL-17A for 7 days have accelerated capacity for in vivo- tumor initiation when injected subcutaneously into syngeneic immune-competent mice, confirming the functional in vivo role that IL-17-immune secreting cells have in inducing pancreatic cancer stemness. Better understanding of the regulation that IL-17-secreting immune cells can impose on pancreatic cancer- tumor initiating cells would be of high importance given the potential translational value of blocking IL-17 signaling for pancreatic cancer prevention and treatment with currently available IL-17 neutralizing monoclonal antibodies or oral small molecule inhibitors. Citation Format: Yu Zhang, Ismet Sahin, Sonal Gupta, Anirban Maitra, Jay K. Kolls, Jennifer Bailey, Steven D Leach, Florencia McAllister.{Authors}. Influence of IL-17-secreting immune cells on pancreatic cancer stemness. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2016 May 12-15; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2016;76(24 Suppl):Abstract nr A76.

The Role of Common Pharmaceutical Agents on the Prevention and Treatment of Pancreatic Cancer.

Survival from pancreatic cancer remains poor. Conventional treatment has resulted in only marginal improvements in survival compared with survival in the previous several decades. Thus, considerable interest has emerged regarding the potential use of common pharmaceutical agents as chemopreventative and chemotherapeutic options. Aspirin, metformin, statins, β-blockers, and bisphosphonates have biologically plausible mechanisms to inhibit pancreatic neoplasia, whereas dipeptidyl-peptidase 4 inhibitors may promote it. Regardless, real-world epidemiological data remain inconclusive. This review examines the hypotheses, evidence, and current state of the literature for each of these medications and their potential roles in the prevention and treatment of pancreatic cancer.

Pancreatic Cancer Chemoprevention Translational Workshop: Meeting Report.

Pancreatic cancer is the fourth leading cause of cancer related deaths in the United States with a 5-year survival rate of less than 10%. The Division of Cancer Prevention of the National Cancer Institute sponsored the Pancreatic Cancer Chemoprevention Translational Workshop on September 10 to 11, 2015. The goal of the workshop was to obtain information regarding the current state of the science and future scientific areas that should be prioritized for pancreatic cancer prevention research, including early detection and intervention for high-risk precancerous lesions. The workshop addressed the molecular/genetic landscape of pancreatic cancer and precursor lesions, high-risk populations and criteria to identify a high-risk population for potential chemoprevention trials, identification of chemopreventative/immunopreventative agents, and use of potential biomarkers and imaging for assessing short-term efficacy of a preventative agent. The field of chemoprevention for pancreatic cancer is emerging, and this workshop was organized to begin to address these important issues and promote multi-institutional efforts in this area. The meeting participants recommended the development of an National Cancer Institute working group to coordinate efforts, provide a framework, and identify opportunities for chemoprevention of pancreatic cancer.

Abstract 823: Prevention of pancreatic cancer by cAMP control

Abstract Smoking and alcoholism are risk factors for the development of pancreatitis-associated pancreatic ductal adenocarcinoma (PDAC). Using a hamster model of pancreatitis-associated PDAC induced by treatment with ethanol in the drinking water and the nicotine-derived nitrosamine 4-methylnitrosamino-(3-pyridyl)-1-butanone (NNK) by subcutaneous injection as well as immunohistochemistry of human PDAC tissue microarrays, we have previously shown that these cancers overexpressed stress neurotransmitters and cAMP while the inhibitory neurotransmitter ã-aminobutyric acid (GABA) was suppressed. Using our hamster model, the current study has tested the hypothesis that cAMP control by GABA supplementation in the drinking water prevents the development of pancreatitis-associated PDAC. Our data reveal strong preventive effects of GABA supplementation on the development of PDAC and pancreatic intraductal neoplasia (PanIN). ELISA assays and immunohistochemistry revealed significant decreases in the levels of cyclic adenosine monophosphate (cAMP) and interleukin 6 accompanied by reductions in the expression of several cancer stem cell markers, phosphorylated signaling proteins associated with cell proliferation and migration in pancreatic exocrine cells of GABA treated animals. We conclude that cAMP control by GABA supplementation inhibits multiple cancer supporting pathways at the level of cancer stem cells, differentiated cancer cells and the immune system, identifying this approach as promising novel tool for the prevention of PDAC in individuals with a history of smoking and alcoholism. Citation Format: Jheelam Banerjee, Arokya M. Papu John, Mohammed H. Al-Wadei, Hildegard M. Schuller. Prevention of pancreatic cancer by cAMP control. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 823.

Abstract 5111: A novel β 2 adrenergic-nerve growth factor feed forward loop promotes pancreatic cancer

Abstract Introduction and objectives: There is increasing evidence that chronic activation of sympathetic neurons can lead to increased noradrenaline levels in the tumor microenvironment (TME) in PDAC. However, the mechanisms by which adrenergic neurotransmitters are delivered to the TME are not well understood. In this study we aimed to investigate the effect of locally and systemically delivered catecholamines into the TME in two well established genetically engineered mouse models of PDAC (Pdx1-Cre/KRasG12D (KC) and Pdx1-Cre/KRasG12D/Trp53R172H (KPC)). Methods: Adrenergic signaling was induced or inhibited in KC or KPC mice and in pancreatic organoids using various pharmacological compounds. Adrenergic receptor expression was assessed by RT-PCR, WB and IHC. Downstream pathways were identified by phosphorylation assays and WB. Adrenergic signaling was modeled in vivo applying restraint stress. To elucidate the crosstalk between nerves and cancer cells, pancreatic spheres and PDAC cells were co-cultured with DRGs and neuronal plasticity was quantified. NGF secretion was measured by RT-PCR and ELISA. Sympathetic denervation of the pancreas and blockage of the 2-receptor was employed as a treatment strategy in KPC mice. Overexpression of NGF was targeted to the mouse pancreas using a novel NGF knockin mouse, which was crossed to KC and KPC mice. Results: ADRB2 was upregulated during pancreatic cancer development. Furthermore, in vitro stimulation of cells harboring an oncogenic KRas mutation with catecholamines resulted in significantly increased sphere forming efficiency. The non-specific -blocker propranolol and the selective 2-blocker ICI 118,551 inhibited this effect. Selective blockade of 2-adrenergic signaling suppressed pancreatic sphere formation caused by co-cultures with DRGs. NGF secretion was stimulated through beta2-adrenergic signaling. Furthermore, restraint stress accelerated PDAC development in KC mice. The effects of stress were prevented by treatment with the selective ADRB2 antagonist ICI 118,551. Specific β2-blocker treatment as well as sympathetic denervation in addition to GEM significantly increased the survival of mice with 3-5 mm tumors in comparison to controls treated by GEM alone. Targeted overexpression of NGF in the mouse pancreas using a novel NGF knockin mouse resulted in marked acceleration of PanIN lesions in the KC mouse and shortened overall survival in KPC mice significantly. Finally, retrospective analysis of a PDAC patient cohort revealed a extension of overall survival in PDAC patients on non-selective -blockers. Conclusions: Taken together, these studies suggest that increased catecholamines can engender a feed forward loop, whereby upregulation of NGF can lead to increased innervation and local NE accumulation, thereby enhancing tumor growth. Therapies targeting these adrenergic and NGF pathways may prove useful in the treatment and prevention of pancreatic cancer. Citation Format: Bernhard W. Renz, Marina Macchini, Yoku Hayakawa, Xiaowei Chen, Zhengyu Jiang, Takayuki Tanaka, C. Benedikt Westphalen, Yagnesh Tailor, Jens Werner, Axel Kleespies, Alina C. Iuga, Daniel L. Worthley, Kenneth P. Olive, Timothy C. Wang. A novel β 2 adrenergic-nerve growth factor feed forward loop promotes pancreatic cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5111.

Abstract 1447: Influence of IL-17-secreting immune cells in pancreatic cancer stemness

Abstract Little is known about how the immune system influences pancreatic cancer stemness. Using a murine model of pancreatic intraepithelial neoplasia (PanIN), we have previously reported that KrasG12D induces expression of IL-17 receptors (IL-17RA) on emerging PanINs, as well as pancreatic infiltration by IL-17-producing CD4+ and gamma-delta-T cells. Forced IL-17 over-expression dramatically accelerates PanIN initiation and progression, while inhibition of IL-17 signaling using either genetic or pharmacologic techniques effectively prevents PanIN formation. When IL-17 signaling was blocked using monoclonal antibodies on transgenic mice harboring PanINs, transcriptional analysis of Kras-mutated epithelial cells revealed significant down-regulation of multiple stemness-related genes: doublecortin-like kinase 1 (Dclk1) [2], Trefoil factor 1 (Tff1)[3], Sonic Hedgehog (SHH) [4], and others. Dclk1 has been recently described as a marker of tumor initiating cells and its functional role in cancer initiation and development is currently being studied. We found that adenovirus mediated-IL-17 overexpression in the murine pancreas harvesting Kras mutation results in PanINs with significantly higher number of Dclk1+ cells that PanINs generated in the presence of a luciferase control virus. Reversely, the genetic ablation of IL-17 in the hematopoietic compartment of the same type of mice resulted in PanINs with significantly lower number of Dclk1+ cells when compared with PanINs from mice transplanted with wild type (WT) bone marrow. We have found that in vitro stimulation of KPC cells (obtained from KrasG12D/+; LSL- Trp53R172H/+; Pdx1−Cre mice) with IL-17A results in direct induction of Dclk1, Aldh1 and SHH protein expression in a time-dependent and dose-dependent fashion, validating the results of our gene microarray in a different system and at the protein level. Furthermore, we have found that one of the mechanisms by which IL-17 induces Dclk-1 and ALDH1a1 is through activation of NF-KB canonical pathway. We found that IL-17 had no effect in KPC cells proliferation in 2D culture. However, stimulation of matrigel embedded- KPC cells with IL-17A resulted in significant increase in tumorspheres formation in vitro. But even more important, KPC cells in vitro incubated with IL-17A for 7 days have accelerated capacity for in vivo- tumor initiation when injected subcutaneously into syngeneic immune-competent mice, confirming the functional in vivo role that IL-17-immune secreting cells have in inducing pancreatic cancer stemness. Better understanding of the regulation that IL-17-secreting immune cells can impose on pancreatic cancer- tumor initiating cells would be of high importance given the potential translational value of blocking IL-17 signaling for pancreatic cancer prevention and treatment with the currently available IL-17 neutralizing monoclonal antibodies. Citation Format: Yu Zhang, Ismet Sahin, Sonal Gupta, Anirban Maitra, Jennifer Bailey, Steven Leach, Florencia McAllister. Influence of IL-17-secreting immune cells in pancreatic cancer stemness. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1447.

Prevention of pancreatic cancer in a hamster model by cAMP decrease.

Smoking and alcoholism are risk factors for the development of pancreatitis-associated pancreatic ductal adenocarcinoma (PDAC). We have previously shown that these cancers overexpressed stress neurotransmitters and cyclic adenosine monophosphate (cAMP) while the inhibitory neurotransmitter γ-aminobutyric acid (GABA) was suppressed. Using a hamster model, the current study has tested the hypothesis that cAMP decrease by GABA supplementation in the drinking water prevents the development of pancreatitis-associated PDAC. Our data reveal strong preventive effects of GABA supplementation on the development of PDAC and pancreatic intraductal neoplasia (PanIN). ELISA assays and immunohistochemistry revealed significant decreases in the levels of cAMP and interleukin 6 accompanied by reductions in the expression of several cancer stem cell markers and phosphorylated signaling proteins, which stimulate cell proliferation, and migration in pancreatic exocrine cells of GABA treated animals. We conclude that cAMP decrease by GABA supplementation inhibits multiple cancer stimulating pathways in cancer stem cells, differentiated cancer cells and the immune system, identifying this approach as promising novel tool for the prevention of PDAC in individuals with a history of smoking and alcoholism.

Targeting tumor-associated macrophages to combat pancreatic cancer.

The tumor microenvironment is replete with cells that evolve with and provide support to tumor cells during the transition to malignancy. The hijacking of the immune system in the pancreatic tumor microenvironment is suggested to contribute to the failure to date to produce significant improvements in pancreatic cancer survival by various chemotherapeutics. Regulatory T cells, myeloid derived suppressor cells, and fibroblasts, all of which constitute a complex ecology microenvironment, can suppress CD8+ T cells and NK cells, thus inhibiting effector immune responses. Tumor-associated macrophages (TAM) are versatile immune cells that can express different functional programs in response to stimuli in tumor microenvironment at different stages of pancreatic cancer development. TAM have been implicated in suppression of anti-tumorigenic immune responses, promotion of cancer cell proliferation, stimulation of tumor angiogenesis and extracellular matrix breakdown, and subsequent enhancement of tumor invasion and metastasis. Many emerging agents that have demonstrated efficacy in combating other types of tumors via modulation of macrophages in tumor microenvironments are, however, only marginally studied for pancreatic cancer prevention and treatment. A better understanding of the paradoxical roles of TAM in pancreatic cancer may pave the way to novel preventive and therapeutic approaches. Here we give an overview of the recruitment and differentiation of macrophages, TAM and pancreatic cancer progression and prognosis, as well as the potential preventive and therapeutic targets that interact with TAM for pancreatic cancer prevention and treatment.