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Background: The life expectancy of pancreatic cancer patients remains minimal. The disease progression may be influenced by type 2 diabetes (T2D) and inflammatory status, although important gaps persist around their joint effects on disease outcome. The aim of this study was to investigate the clinical significance of the tumour immune microenvironment on pancreatic cancer prognosis in relation to T2D status., Method: Tumour-infiltrating macrophages, neutrophils and eosinophils were studied in primary pancreatic tumours and paired lymph node metastases in relation to patient and tumour characteristics, T2D status and overall survival in a retrospective cohort of patients with resectable pancreatic cancer in Sweden., Results: Of the 80 included pancreatic cancer patients, 22 (27.2%) had T2D. The diabetic pancreatic cancer patients had significantly higher systemic high white blood cell count than those without diabetes (P = 0.028). Macrophage infiltration levels were higher in lymph node metastases compared with primary tumours (P = 0.040) among pancreatic cancer patients with diabetes. Type 2 diabetes or intra-tumoural leukocyte (macrophage, neutrophil or eosinophil) infiltration alone did not significantly influence pancreatic cancer prognosis. However, among cancer patients with T2D high macrophage or neutrophil tumour-infiltration was associated with a significant reduction in overall survival (adjusted hazard ratio [HR] 7.2; 95% CI 1.5-35.0 and HR 5.4; 95% CI 1.1-26.3, respectively)., Conclusion: These results demonstrate associations between T2D and enhanced inflammatory processes with significant implications on survival among pancreatic cancer patients with T2D. Validation in larger independent patient cohorts may identify additional prognostic tools and improved treatment strategies for specific patient subsets., (Copyright © 2017 IAP and EPC. Published by Elsevier B.V. All rights reserved.)

Pancreatic cancer is associated with a highly abundant stroma and low-grade inflammation. In the local tumour microenvironment, elevated glucose levels, the presence of tumour-associated stellate cells and macrophages are hypothesised to promote the tumour progression and invasion. The present study investigated the influence by the microenvironment on pancreatic cancer cell invasion in vitro. After co-culture with tumour-associated pancreatic stellate cells (TPSCs), pancreatic cancer cells displayed up to 8-fold reduction in levels of epithelial-mesenchymal transition (EMT) markers E-cadherin and ZO-1, while β-catenin and vimentin levels were increased. A 3D organotypic model showed that TPSCs stimulated pancreatic cancer cell invasion, both as single cell (PANC-1) and cohort (MIAPaCa-2) invasion. The combined presence of TPSCs and M2-like macrophages induced invasion of the non-invasive BxPC-3 cells. High glucose conditions further enhanced changes in EMT markers as well as the cancer cell invasion. In summary, co-culture with TPSCs induced molecular changes associated with EMT in pancreatic cancer cells, regardless of differentiation status, and the organotypic model demonstrated the influence of microenvironmental factors, such as glucose, stellate cells and macrophages, on pancreatic cancer cell invasion., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Pancreatic stellate cells (PSCs) play a key role in the dense desmoplastic stroma associated with pancreatic ductal adenocarcinoma. Studies on human PSCs have been minimal due to difficulty in maintaining primary PSC in culture. We have generated the first conditionally immortalized human non-tumor (NPSC) and tumor-derived (TPSC) pancreatic stellate cells via transformation with the temperature-sensitive SV40 large T antigen and human telomerase (hTERT). These cells proliferate at 33°C. After transfer to 37°C, the SV40LT is switched off and the cells regain their primary PSC phenotype and growth characteristics. NPSC contained cytoplasmic vitamin A-storing lipid droplets, while both NPSC and TPSC expressed the characteristic markers αSMA, vimentin, desmin and GFAP. Proteome array analysis revealed that of the 55 evaluated proteins, 27 (49%) were upregulated ≥3-fold in TPSC compared to NPSC, including uPA, pentraxin-3, endoglin and endothelin-1. Two insulin-like growth factor binding proteins (IGFBPs) were inversely expressed. Although discordant IGFBP-2 and IGFBP-3 levels, IGF-I was found to stimulate proliferation of both NPSC and TPSC. Both basal and IGF-I stimulated motility was significantly enhanced in TPSC compared to NPSC. In conclusion, these cells provide a unique resource that will facilitate further study of the active stroma compartment associated with pancreatic cancer., (Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.)

At the time of diagnosis, almost 80% of pancreatic cancer patients present with new-onset type 2 diabetes (T2D) or impaired glucose tolerance. T2D and pancreatic cancer are both associated with low-grade inflammation. Tumour-associated macrophages (TAMs) have a key role in cancer-related inflammation, immune escape, matrix remodelling and metastasis. In this study, the interplay between tumour cells and immune cells under the influence of different glucose levels was investigated. Human peripheral blood mononuclear cells were exposed in vitro to conditioned medium from BxPC-3 human pancreatic cancer cells, in normal (5 mM) or high (25 mM) glucose levels. Flow cytometry analyses demonstrated that tumour-derived factors stimulated differentiation of macrophages, with a mixed classical (M1-like) and alternatively activated (M2-like) phenotype polarisation (CD11c(+)CD206(+)). High-glucose conditions further enhanced the tumour-driven macrophage enrichment and associated interleukin (IL)-6 and IL-8 cytokine levels. In addition, hyperglycaemia enhanced the responsiveness of tumour-educated macrophages to lipopolysaccharide, with elevated cytokine secretion compared with normal glucose levels. Tumour-educated macrophages were found to promote pancreatic cancer cell invasion in vitro, which was significantly enhanced at high glucose. The anti-diabetic drug metformin shifted the macrophage phenotype polarisation and reduced the tumour cell invasion at normal, but not high, glucose levels. In conclusion, this study demonstrates that pancreatic cancer cells stimulate differentiation of macrophages with pro-tumour properties that are further enhanced by hyperglycaemia. These findings highlight important crosstalk between tumour cells and TAMs in the local tumour microenvironment that may contribute to disease progression in pancreatic cancer patients with hyperglycaemia and T2D.

Background: Epidemiological studies have shown direct associations between type 2 diabetes and obesity, both conditions associated with hyperglycaemia and hyperinsulinemia, and the risk of pancreatic cancer. Up to 80% of pancreatic cancer patients present with either new-onset type 2 diabetes or impaired glucose tolerance at the time of diagnosis. Recent population studies indicate that the incidence of pancreatic cancer is reduced among diabetics taking metformin. In this study, the effects of exposure of pancreatic cancer cells to high glucose levels on their growth and response to metformin were investigated., Methods: The human pancreatic cancer cell lines AsPC-1, BxPC-3, PANC-1 and MIAPaCa-2 were grown in normal (5 mM) or high (25 mM) glucose conditions, with or without metformin. The influence by metformin on proliferation, apoptosis and the AMPK and IGF-IR signalling pathways were evaluated in vitro., Results: Metformin significantly reduced the proliferation of pancreatic cancer cells under normal glucose conditions. Hyperglycaemia however, protected against the metformin-induced growth inhibition. The anti-proliferative actions of metformin were associated with an activation of AMP-activated protein kinase AMPKThr172 together with an inhibition of the insulin/insulin-like growth factor-I (IGF-I) receptor activation and downstream signalling mediators IRS-1 and phosphorylated Akt. Furthermore, exposure to metformin during normal glucose conditions led to increased apoptosis as measured by poly(ADP-ribose) polymerase (PARP) cleavage. In contrast, exposure to high glucose levels promoted a more robust IGF-I response and Akt activation which correlated to stimulated AMPKSer485 phosphorylation and impaired AMPKThr172 phosphorylation, resulting in reduced anti-proliferative and apoptotic effects by metformin., Conclusion: Our results indicate that metformin has direct anti-tumour activities in pancreatic cancer cells involving AMPKThr172 activation and suppression of the insulin/IGF signalling pathways. However, hyperglycaemic conditions enhance the insulin/IGF-I responses resulting in an altered AMPK activation profile and prevent metformin from fully switching off the growth promoting signals in pancreatic cancer cells.

Background: Polysaccharide-K (PSK, Krestin(®)) is a natural remedy and one of the most commonly used medicinal mushroom extracts. It has been used as oral adjuvant treatment in cancer therapy in Japan and other Asian countries for more than 40 years. PSK is thought to be an immune modulator, however, its antitumor actions remain undefined. The aim of the present study was to investigate underlying mechanisms by which PSK exerts its antitumor effects on malignant epithelial cells., Methods: Antitumor activities of PSK were evaluated on multiple human pancreatic adenocarcinoma cells in vitro. Cell viability, apoptotic pathways, cytokine expression and involvement of TLR2 and TLR4 were monitored by MTT, flow cytometry, Western blotting and protein arrays., Results: We demonstrate that PSK acts as a growth inhibitor for pancreatic cancer cells, known otherwise to be highly resistant to conventional chemotherapies. Pancreatic cancer cells can be protected against PSK-mediated growth inhibition by neutralizing antibodies against TLR2 and TLR4. The antiproliferative actions were associated with upregulated cell cycle regulatory p21(WAF/Cip1) and pro-apoptotic protein Bax levels, resulting in cell cycle arrest and induction of apoptosis. In addition, a significant growth inhibition and additive effect was observed with PSK and gemcitabine administered as combined treatment., Conclusion: While previous studies have emphasized the potential importance of PSK in immune activation, the present results uncover additional mechanisms on epithelial cells that may contribute to the antitumor effects provided by PSK as suggested by clinical observations., (Copyright © 2012 IAP and EPC. Published by Elsevier B.V. All rights reserved.)

Background: Pancreatic ductal adenocarcinoma is frequently associated with aberrant activation of the Ras/Raf/MAPK pathway and cyclooxygenase-2 (COX-2) overexpression. This study evaluated the potential for combining the multikinase inhibitor sorafenib and the specific COX-2 inhibitor celecoxib as therapy in pancreatic ductal adenocarcinoma cells., Methods: BxPC-3, MIAPaCa-2, PANC-1 and AsPC-1 pancreatic adenocarcinoma cells were exposed to sorafenib and celecoxib combined treatment in vitro. Cell viability and various growth promoting and survival signaling pathways were monitored by MTT, flow cytometry and Western blotting., Results: Combined treatment with sorafenib and celecoxib synergistically inhibited pancreatic adenocarcinoma cell proliferation. This regimen produced combination index (CI) values between 0.67 and 0.92 for the various cell lines, indicating significant synergistic interactions between sorafenib and celecoxib, which also markedly inhibited the migratory capacity. The growth inhibition was associated with an accumulation of cells in the G(0)/G(1) phase of the cell cycle and induction of apoptosis. These changes were accompanied by a significant reduction of p21(WAF1/Cip1) levels, where celecoxib sensitized the cells to sorafenib-mediated p21(WAF1/Cip1) suppression., Conclusion: These results suggest that combined treatment with sorafenib and celecoxib synergistically induce growth inhibition and apoptosis in pancreatic adenocarcinoma cells through a process involving p21(WAF1/Cip1) suppression., (Copyright © 2012 IAP and EPC. Published by Elsevier B.V. All rights reserved.)

Background: Pancreatic cancer is a highly malignant cancer and the fourth leading cause of cancer-related death. It is characterized by a rapid disease progression, a highly invasive tumor phenotype, and frequently resistance to chemotherapy. Despite significant advances in diagnosis, staging, and surgical management of the disease during the past decade, prognosis of pancreatic cancer is still dismal., Methods and Results: The phosphatidylinositol 3-kinase (PI3K) signaling pathways regulate cellular growth, metabolism, survival, and motility in pancreatic cancer. Pancreatic cancer is associated with a high degree of genetic alterations that can result in aberrant activation of the PI3K signaling pathway. Elucidating the role of the PI3K signaling pathway in pancreatic cancer may thus be both meaningful and necessary., Conclusion: Improved knowledge of the PI3K signaling pathway in pancreatic cancer would furthermore be helpful in understanding mechanisms of tumor initiation and progression, and in identifying appropriate targeted anticancer treatment in pancreatic cancer. and IAP., (Copyright © 2011 S. Karger AG, Basel.)