Pancreatic ductal adenocarcinoma (PDAC) is poorly responsive to therapies and histologically contains a paucity of neoplastic cells embedded within a dense desmoplastic stroma. Within the stroma, cancer-associated fibroblasts (CAF) secrete tropic factors and extracellular matrix components, and have been implicated in PDAC progression and chemotherapy resistance. We recently identified two distinct CAF subtypes characterized by either myofibroblastic or inflammatory phenotypes; however, the mechanisms underlying their diversity and their roles in PDAC remain unknown. Here, we use organoid and mouse models to identify TGFβ and IL1 as tumor-secreted ligands that promote CAF heterogeneity. We show that IL1 induces LIF expression and downstream JAK/STAT activation to generate inflammatory CAFs and demonstrate that TGFβ antagonizes this process by downregulating IL1R1 expression and promoting differentiation into myofibroblasts. Our results provide a mechanism through which distinct fibroblast niches are established in the PDAC microenvironment and illuminate strategies to selectively target CAFs that support tumor growth. SIGNIFICANCE: Understanding the mechanisms that determine CAF heterogeneity in PDAC is a prerequisite for the rational development of approaches that selectively target tumor-promoting CAFs. Here, we identify an IL1-induced signaling cascade that leads to JAK/STAT activation and promotes an inflammatory CAF state, suggesting multiple strategies to target these cells . .

Systemic and local chronic inflammation might enhance the risk of pancreatic ductal adenocarcinoma (PDAC), and PDAC-associated inflammatory infiltrate in the tumor microenvironment concurs in enhancing tumor growth and metastasis. Inflammation is closely correlated with immunity, the same immune cell populations contributing to both inflammation and immune response. In the PDAC microenvironment, the inflammatory cell infiltrate is unbalanced towards an immunosuppressive phenotype, with a prevalence of myeloid derived suppressor cells (MDSC), M2 polarized macrophages, and T, over M1 macrophages, dendritic cells, and effector CD4⁺ and CD8⁺ T lymphocytes. The dynamic and continuously evolving cross-talk between inflammatory and cancer cells might be direct and contact-dependent, but it is mainly mediated by soluble and exosomes-carried cytokines. Among these, tumor necrosis factor alpha (TNFα) plays a relevant role in enhancing cancer risk, cancer growth, and cancer-associated cachexia. In this review, we describe the inflammatory cell types, the cytokines, and the mechanisms underlying PDAC risk, growth, and progression, with particular attention on TNFα, also in the light of the potential risks or benefits associated with anti-TNFα treatments.

BACKGROUND:For prognostic evaluation of pancreatic ductal adenocarcinoma (PDAC), the only well-established serum marker is carbohydrate antigen CA19-9. To improve the accuracy of survival prediction, we tested the efficacy of inflammatory serum markers. METHODS:A preoperative serum panel comprising 48 cytokines plus high-sensitivity CRP (hs-CRP) was analyzed in 173 stage I-III PDAC patients. Analysis of the effect of serum markers on survival utilized the Cox regression model, with the most promising cytokines chosen with the aid of the lasso method. We formed a reference model comprising age, gender, tumor stage, adjuvant chemotherapy status, and CA19-9 level. Our prognostic study model incorporated these data plus hs-CRP and the cytokines. We constructed time-dependent ROC curves and calculated an integrated time-averaged area under the curve (iAUC) for both models from 1 to 10 years after surgery. RESULTS:Hs-CRP and the cytokines CTACK, MIF, IL-1β, IL-3, GRO-α, M-CSF, and SCF, were our choices for the prognostic study model, in which the iAUC was 0.837 (95% CI 0.796-0.902), compared to the reference model's 0.759 (95% CI 0.691-0.836, NS). These models divided the patients into two groups based on the maximum value of Youden's index at 7.5 years. In our study model, 60th percentile survival times were 4.5 (95% CI 3.7-NA) years (predicted high-survival group, n = 34) and 1.3 (95% CI 1.0-1.7) years (predicted low-survival group, n = 128), log rank p < 0.001. By the reference model, the 60th percentile survival times were 2.8 (95% CI 2.1-4.4) years (predicted high-survival group, n = 44) and 1.3 (95% CI 1.0-1.7) years (predicted low-survival group, n = 118), log rank p < 0.001. CONCLUSION:Hs-CRP and the seven cytokines added to the reference model including CA19-9 are potential prognostic factors for improved survival prediction for PDAC patients.

PURPOSE:We evaluated prognostic indicators based on inflammatory and nutritional factors, namely, the modified Glasgow Prognostic Score (mGPS), the Prognostic Nutritional Index (PNI), the neutrophil/lymphocyte ratio (NLR), and the platelet/lymphocyte ratio (PLR), to determine their efficiency and significance after pancreaticoduodenectomy for pancreatic cancer. METHODS:The subjects of this study were 46 patients who underwent pancreaticoduodenectomy for pancreatic cancer between October 2007 and December 2014. Patients were divided into preoperative mGPS (0/1 and 2), PNI (<40 and ≥40), NLR (<2.5 and ≥2.5), and PLR (<200 and ≥200) groups, to evaluate various perioperative outcomes. RESULTS:Hemoglobin concentrations were significantly lower (P = 0.019), whereas intra-abdominal bleeding was significantly higher (P = 0.040) in the PNI (<40) group than in the PNI (≥40) group. The incidence of postoperative pneumonia was significantly higher in the mGPS (2) group (P = 0.009), and surgical complications greater than grade 3 (Clavien-Dindo classification) were significantly increased in the NLR (≥2.5) group (P = 0.041). Overall survival rates in the PNI (<40) (P = 0.019), NLR (≥2.5) (P = 0.001), and PLR (≥200) (P < 0.001) groups were significantly lower than those in the other groups. The PLR was the only independent prognostic indicator (P = 0.002) according to multivariate analysis. CONCLUSIONS:The mGPS, PNI, and NLR were effective predictive indicators of postoperative complications. The PLR was the most useful prognostic indicator for pancreatic cancer patients after pancreaticoduodenectomy.

Originally described as an interferon (IFN)-γ-inducing factor, interleukin (IL)-18 has been reported to be involved in Th1 and Th2 immune responses, as well as in activation of NK cells and macrophages. There is convincing evidence that IL-18 plays an important role in various pathologies (i.e. inflammatory diseases, cancer, chronic obstructive pulmonary disease, Crohn's disease and others). Recently, IL-18 has also been shown to execute specific effects in pancreatic diseases, including acute and chronic pancreatitis, as well as pancreatic cancer. The aim of this study was to give a profound review of recent data on the role of IL-18 and its potential as a therapeutic target in pancreatic diseases. The existing data on this topic are in part controversial and will be discussed in detail. Future studies should aim to confirm and clarify the role of IL-18 in pancreatic diseases and unravel their molecular mechanisms.

Pancreatic cancer is considered as one of the most lethal types of cancer due to its poor prognosis and lack of effective therapeutic approaches. Although many studies have been done on pancreatic cancer, the current treatment methods did not exhibit successful results. Hence, novel strategies are needed for treatment of pancreatic cancer. The microenvironment of pancreatic cancer contains many factors such as inflammatory cytokines and tumor associated macrophages (TAMs), which influence the tumor's status. These factors can be upregulated and consequently lead to exacerbation of tumor progression. Understanding the role of pro- and anti-inflammatory cytokines and the function of TAMs in the pancreatic cancer microenvironment might lead to development and improvement of novel strategies in the diagnosis and treatment of pancreatic cancer and may result in promising treatments for this type of cancer.

Chronic inflammation is known to be a risk for many cancers, including pancreatic cancer. Heavy alcohol drinking and cigarette smoking are major causes of pancreatitis, and epidemiological studies have shown that smoking and chronic pancreatitis are risk factors for pancreatic cancer. Meanwhile, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) are elevated in pancreatitis and pancreatic cancer tissues in humans and in animal models. Selective inhibitors of iNOS and COX-2 suppress pancreatic cancer development in a chemical carcinogenesis model of hamsters treated with N-nitrosobis(2-oxopropyl)amine (BOP). In addition, hyperlipidemia, obesity, and type II diabetes are also suggested to be associated with chronic inflammation in the pancreas and involved in pancreatic cancer development. We have shown that a high-fat diet increased pancreatic cancer development in BOP-treated hamsters, along with aggravation of hyperlipidemia, severe fatty infiltration, and increased expression of adipokines and inflammatory factors in the pancreas. Of note, fatty pancreas has been observed in obese and/or diabetic cases in humans. Preventive effects of anti-hyperlipidemic/anti-diabetic agents on pancreatic cancer have also been shown in humans and animals. Taking this evidence into consideration, modulation of inflammatory factors by anti-inflammatory agents will provide useful data for prevention of pancreatic cancer.

OBJECTIVES:Inflammation and inflammatory conditions have been associated with pancreatic cancer risk and progression in a number of clinical, epidemiological, and animal model studies. The goal of the present study is to identify plasma markers of inflammation associated with survival of pancreatic cancer patients, and assess their joint contribution to patient outcome. METHODS:We measured circulating levels of four established markers of inflammation (C-reactive protein (CRP), interleukin-6 (IL-6), soluble tumor necrosis factor receptor type II (sTNF-RII), and macrophage inhibitory cytokine-1 (MIC-1)) in 446 patients enrolled in an ongoing prospective clinic-based study. Hazard ratios (HRs) and 95% confidence intervals (CI) for death were estimated using multivariate Cox proportional hazards models. RESULTS:Overall mortality was significantly increased in patients in the top quartile of CRP (HR = 2.52, 95% CI: 1.82-3.49), IL-6 (HR = 2.78, 95% CI: 2.03-3.81), sTNF-RII (HR = 2.00, 95% CI: 1.46-2.72), and MIC-1 (HR = 2.53, 95% CI: 1.83-3.50), compared to those in the bottom quartile (P-trend <0.0001 for all four comparisons). Furthermore, patients with higher circulating concentrations of all four cytokines had a median survival of 3.7 months; whereas, those with lower levels had a median survival of 19.2 months (HR = 4.55, 95% CI: 2.87-7.20, P-trend <0.0001). CONCLUSION:Individual elevated plasma inflammatory cytokines are associated with significant and dramatic reductions in pancreatic cancer patient survival. Furthermore, we observed an independent combined effect of those cytokines on patient survival, suggesting that multiple inflammatory pathways are likely involved in PDAC progression. Future research efforts to target the inflammatory state using combination strategies in pancreatic cancer patients are warranted.