Pancreatic stellate cells (PSCs) are the key precursor cells for cancer-associated fibroblasts (CAFs) in pancreatic tumor stroma. Although depletion of tumor stroma is debatable, attenuation of PSC activity is still an interesting strategy to treat pancreatic cancer. In this study, we explored miRNA as therapeutic targets in tumor stroma and found miR-199a-3p and miR-214-3p induced in patient-derived pancreatic CAFs as well as in TGF-β-activated human PSCs (hPSCs). Inhibition of miR-199a or miR-214 using their hairpin inhibitors in hPSCs significantly inhibited their TGFβ-induced differentiation (gene and protein levels of α-SMA, Collagen, PDGFβR), migration and proliferation. Furthermore, heterospheroids of Panc-1 and hPSCs were prepared, which attained smaller size when hPSCs were transfected with anti-miR-199a or -214 than those transfected with control anti-miR. The conditioned medium obtained from TGFβ-activated hPSCs induced tumor cell proliferation and endothelial cell tube formation, but these effects were abrogated when hPSCs were transfected with anti-miR-199a or miR-214. Moreover, IPA analyses revealed signaling pathways related to miR-199a (TP53, mTOR, Smad1) and miR-214 (PTEN, Bax, ING4). Taken together, this study reveals miR-199a-3p and miR-214-3p as major regulators of PSC activation and PSC-induced pro-tumoral effects, representing them as key therapeutic targets in PSCs in pancreatic cancer.

The interplay between the tumor cells and the surrounding stroma creates inflammation, which promotes tumor growth and spread. The inflammation is a hallmark for pancreatic adenocarcinoma (PDAC) and is to high extent driven by IL-1α. IL-1α is expressed and secreted by the tumor cells and exerting its effect on the stroma, i.e. cancer associated fibroblasts (CAF), which in turn produce massive amount of inflammatory and immune regulatory factors. IL-1 induces activation of transcription factors such as nuclear factor-κβ (NF-κβ), but also activator protein 1 (AP-1) via the small G-protein Ras. Dysregulation of Ras pathways are common in cancer as this oncogene is the most frequently mutated in many cancers. In contrast, the signaling events leading up to the expression of IL-1α by tumor cells are not well elucidated. Our aim was to examine the signaling cascade involved in the induction of IL-1α expression in PDAC. We found p38MAPK, activated by the K-Ras signaling pathway, to be involved in the expression of IL-1α by PDAC as blocking this pathway decreased both the gene and protein expression of IL-1α. Blockage of the P38MAPK signaling in PDAC also dampened the ability of the tumor cell to induce inflammation in CAFs. In addition, the IL-1α autocrine signaling regulated the migratory capacity of PDAC cells. Taken together, the blockage of signaling pathways leading to IL-1α expression and/or neutralization of IL-1α in the PDAC microenvironment should be taken into consideration as possible treatment or complement to existing treatment of this cancer.

The tumor microenvironment in pancreatic ductal adenocarcinoma (PDAC) is dynamic with an extensive interaction between the stroma and tumor cells. The aim for this study was to delineate the cross-talk between PDAC and cancer-associated fibroblasts (CAFs) with focus on the mechanism creating the chronic inflammatory tumor milieu. We assessed the effects of the cross-talk between primary PDAC and CAF cell lines on the creation and sustenance of the inflammatory tumor microenvironment in pancreatic cancer. The coculture of primary PDAC and CAF cell lines enhanced the levels of inflammatory factors including IL-1á, IL-6, CXCL8, VEGFA, CCL20, and COX-2. CAFs were superior to tumor cells regarding the production of most inflammatory factors and tumor cell associated IL-1á was established as the initiator of the enhanced production of inflammatory factors through the binding of IL-1á to the active IL-1 receptor (IL-1R1) expressed predominantly by CAFs. Furthermore, we found a positive correlation between IL-1á and CXCL8 expression levels in PDAC tissues and correlation between IL-1á expression and the clinical outcome of the patients. This confirmed an important role for the IL-1 signaling cascade in the creation and sustenance of a tumor favorable microenvironment. Neutralization of the IL-1á signaling efficiently diminished the cross-talk induced production of inflammatory factors. These data suggest that the cross-talk between PDAC cells and the main stroma cell type, i.e. CAFs, is one essential factor in the formation of the inflammatory tumor environment and we propose that neutralization of the IL-1á signaling might be a potential therapy for this cancer.

Tumor microenvironment is composed of tumor cells, fibroblasts, and infiltrating immune cells, which all work together and create an inflammatory environment favoring tumor progression. The present study aimed to investigate the role of the desmoplastic stroma in pancreatic ductal adenocarcinoma (PDAC) regarding expression of inflammatory factors and infiltration of immune cells and their impact on the clinical outcome. The PDAC tissues examined expressed significantly increased levels of immunomodulatory and chemotactic factors (IL-6, TGF beta, IDO, COX-2, CCL2, and CCL20) and immune cell-specific markers corresponding to macrophages, myeloid, and plasmacytoid dendritic cells (DCs) as compared to controls. Furthermore, short-time survivors had the lowest levels of DC markers. Immunostainings indicated that the different immune cells and inflammatory factors are mainly localized to the desmoplastic stroma. Therapies modulating the inflammatory tumor microenvironment to promote the attraction of DCs and differentiation of monocytes into functional DCs might improve the survival of PDAC patients.

The tumor microenvironment in pancreatic ductal adenocarcinoma (PDAC) is dynamic with an extensive interaction between the stroma and tumor cells. Our aim for this study was to delineate the cross-talk between PDAC and cancer-associated fibroblasts (CAFs) with focus on the mechanism creating the chronic inflammatory tumor milieu. We assessed the effect cross talk between primary PDAC and CAF cell lines propagated from tumors had on the creation and sustenance of an inflammatory environment and what factors that were involved in establishing the inflammation.

The coculture of PDAC and CAF cell lines, propagated from tumor tissues, enhanced the levels of inflammatory factors including IL-1α, IL-6, CXCL8, VEGFA, CCL20, and COX-2. The production of these factors correlated with the expression detected in vivo in PDAC tissues. The key producers of nearly all inflammatory factors were the CAFs and not the tumor cells.

IL-1α was produced by the tumor cell lines, whereas almost all IL-1RI was expressed by CAFs thus corresponding to their in vivo expression profile in PDAC tissues, indicating a role for the IL-1 signaling cascade in a tumor favorable microenvironment. Neutralization of the IL-1α pathway efficiently diminished the cross talk induced production of inflammatory factors, both in stroma and tumor cells. These data suggest that the cross-talk between PDAC cells and the main stroma cell type, i.e. CAFs, is one contributing factor in the formation of the inflammatory tumor environment and we propose that the neutralization of IL-1α pathway might be a potential therapy for this cancer.

Background: Dendritic cells (DCs) isolated from tumor bearing animals or from individuals with solid tumors display functional abnormalities and the DC impairment has emerged as one mechanism for tumor evasion from the control of the immune system. Ductal pancreatic adenocarcinoma (PDAC), the most common pancreatic cancer, is recognized as a very aggressive cancer type with a mortality that almost matches the rate of incidence. Methods: We examined the systemic influence ductal pancreatic adenocarcinoma ( PDAC) exerted on levels of peripheral blood DCs and inflammatory mediators in comparison to the effects exerted by other pancreatic tumors, chronic pancreatitis, and age-matched controls. Results: All groups examined, including PDAC, had decreased levels of myeloid DCs (MDC) and plasmacytoid DCs (PDC) and enhanced apoptosis in these cells as compared to controls. We found elevated levels of PGE2 and CXCL8 in subjects with PDAC, and chronic pancreatitis. Levels of these inflammatory factors were in part restored in PDAC after tumor resection, whereas the levels of DCs were impaired in the majority of these patients similar to 12 weeks after tumor removal. Our results prove that solid pancreatic tumors, including PDAC, systemically affect blood DCs. The impairments do not seem to be tumor-specific, since similar results were obtained in subjects with chronic pancreatitis. Furthermore, we found that PDAC patients with a survival over 2 years had significant higher levels of blood DCs compared to patients with less than one year survival. Conclusions: Our findings points to the involvement of inflammation in the destruction of the blood MDCs and PDCs. Furthermore, the preservation of the blood DCs compartment in PDAC patients seems to benefit their ability to control the disease and survival.

Tumor microenvironment is composed of tumor cells, fibroblasts, and infiltrating immune cells, and other cellular components, which work together and create an inflammatory environment favoring tumor progression. The present study aimed to characterize the expression and location of immune cells and investigate inflammatory factors that influence pancreatic ductal adenocarcinoma (PDAC).

Methods: qPCRs and immunohistological stainings were performed for inflammatory factors and immune cells localized in tumor tissues from patients with PDAC (N=30).

Results: All PDAC tissues had significant increased levels of inflammatory and chemotactic factors such as IL-1α, COX-2, CXCL8, CCL2, and CCL20 as compared to controls. The PDAC stroma, i.e. the fibrosis surrounding the tumor, was the main producer of these factors with the exception of IL-1α, which was expressed by tumor cells and some infiltrating immune cells. The gene expression for immune cell specific markers CD163, CD1c, CD303, and CD8, corresponding to macrophages, myeloid dendritic cells (DCs), plasmacytoid DCs, and cytotoxic T lymphocytes (CTL), respectively, were all significantly increased in PDAC tissues. Immunostaining of the tumor tissue confirmed the elevated levels of infiltrating macrophages, DCs, mature DCs, and cytotoxic T lymphocytes (CTL). The different immune cells were in nearly all cases localized in the fibrotic tissue adjacent to tumor nests. Production of CXCL8 mRNA and protein by the stroma was dependent on the tumor expression of IL-1α. Of importance, we found a correlation in expression of the proinflammatory factor IL-1α and the PDAC patients’ survival time.

Conclusion: PDAC cells seem to take advantage of IL-1α to create an inflammatory microenvironment with high degree of fibrosis and the ability to both recruit and activate immune cells and the level of inflammation in this environment influenced the clinical outcome for the patients. Therapies targeting the inflammation might be beneficial for the survival of patients with PDAC.

Background: Much evidence exists regarding the fact that blood DCs, both myeloid DCs (MDCs) and plasmacytoid DCs (PDCs), are negatively affected in different types of cancer, with both reduced numbers and impaired functionality. Functional impairment of DCs in patients with pancreatic ductal adenocarcinoma (PDAC), may contribute to the poor clinical outcome. The aim of this study was to examine the effects PDAC had on blood DCs and elucidate the underlying mechanism responsible for the DC impairment. Methodology/Principal Findings: We examined the systemic influence PDAC exerted on blood DCs by ex vivo measuring numerous activation and maturation markers expressed on these cells. Furthermore, the effect patient plasma and the inflammatory factors CXCL8 and PGE(2) had on purified MDCs and PDCs from healthy donors was assessed and compared to the DCs existing in PDAC patients. We found a partial maturation of the blood MDCs and PDCs in PDAC patients with significantly enhanced expression of CD83, CD40, B7H3, PDL-1, CCR6, and CCR7 and decreased expression of ICOSL, and DCIR. These changes lead to impairment in their immunostimulatory function. Furthermore, chronic pancreatitis gave rise to DCs with similar semi-mature phenotype as seen in PDAC. Low expression of ICOSL was associated with poor prognosis. We found that the mechanism underlying this semi-maturation of DCs was inflammatory factors existing in the PDAC patients plasma. Of note, PGE2, which is elevated PDAC patient plasma, was one contributing factor to the changes seen in MDCs and PDCs phenotype. Conclusion/Significance: Our findings point to a role for the systemic inflammation in transforming blood MDCs and PDCs into semi-mature cells in PDAC patients and we show a correlation between maturation status and clinical outcome. Thus, means to preserve a functional blood DC compartment in PDAC patients by diminishing the inflammation could facilitate their ability to control the disease and improve survival.

Pancreatic cancer is one of the most lethal cancers and despite all research efforts the last 50 years, there are still no effective therapy for this terrible disease. Until quite recently most research in the field of pancreatic duct adenocarcinoma (PDAC) was focused on the tumor cells and mechanisms essential for their proliferation and survival. However, the tumor does not only consist of tumor cells, rather a combination of tumor cells and numerous stroma cell types, i.e. the tumor microenvironment. The tumor cells have developed the ability to activate the surrounding cells to produce factors important for the progression of the tumor. Cancer associated fibroblasts (CAFs) are the major stroma component and as much as 70% of the total PDAC tumor mass consists of these cells. In this thesis I have investigated the mechanisms involved in the cross-talk between tumor cells and CAFs and distinguished the local and systemic effects of this communication. Tumor derived IL-1α was identified as an important factor creating the inflammatory profile seen in CAFs. In PDAC patients, IL-1α was detected in 90% of the tumors and high expression was associated with poor clinical outcome. Moreover, the PDAC tumors had elevated expression levels of many inflammatory factors that were induced in CAFs by the tumor derived IL-1α in vitro. Consequently, this high expression of inflammatory factors in CAFs will attract immune cells including tumor associated macrophages (TAMs), dendritic cells (DCs), and CD8+ T cells. This indicates an immune suppressive role of CAFs, protecting the tumor cells by acting as decoy targets for immune cells homing into the tumor. The inflammatory factors produced in the PDAC microenvironment did not only affect the infiltrating immune cells, but had also systemic effects that included decreased levels of blood DCs in PDAC patients. Furthermore, these myeloid and plasmacytoid DCs were partly activated and had a semi mature phenotype and impaired immunostimulatory function. Low levels of blood DCs were direct associated with poor patient prognosis and the same was seen for low expression of ICOSL by the DCs.

The findings presented in this thesis indicate an essential role for the cross-talk between tumor cells and stroma in the production of tumor  promoting factors. Treatment of PDAC patients with drugs that target the IL-1α signaling pathway could prevent the communication between these cells, thus reduce the amount of inflammatory factors both locally and systemically. Altogether, our findings support the idea that neutralization of the IL-1α signaling molecule could be a promising therapy for pancreatic cancer.

The findings presented in this thesis indicate an essential role for the cross-talk between tumor cells and stroma in the production of tumor promoting factors. Treatment of PDAC patients with drugs that target the IL-1α signaling pathway could prevent the communication between these cells, thus reduce the amount of inflammatory factors both locally and systemically. Altogether, our findings support the idea that neutralization of the IL-1α signaling molecule could be a promising therapy for pancreatic cancer.

Mindre än 5% av patienterna som drabbas av cancer i bukspottkörteln förväntas överleva i mer än fem år. De typiska symtomen kommer sent och sjukdomen framskrider snabbt. Några av de riskfaktorer som identifierats är tobaksrökning, fetma och typ 2 diabetes.

Forskningen har hittills siktat in sig på tumörcellerna och de mekanismer de använder för att överleva och föröka sig. Men en tumör innehåller också normala kroppsceller och vid bukspottkörtelcancer kan så mycket som 70 procent bestå av i sig ofarliga bindvävsceller. Miljön i tumören skapas av samspelet mellan dessa celltyper. De cancerceller som är bäst på att utnyttja omgivningen för sin tillväxt fortlever och för sina egenskaper vidare. En sådan egenskap är att kunna manipulera bindvävsceller till att producera signalsubstanser och tillväxtfaktorer som gynnar tumören.

Mekanismerna bakom denna kommunikation har studerats och ett viktigt fynd var att tumörcellerna producerar signalämnet interleukin 1-alpha (IL-1a). Detta protein upptäcktes i 90 procent av de undersökta tumörerna, och var kopplat till dålig prognos hos patienterna.

Signalen via IL-1a sätter igång tillverkningen av substanser som behövs för nybildning och tillväxt av blodkärl, i sin tur en förutsättning för att tumören ska leva vidare och växa. Proteinet stimulerar också celldelning i tumören, bidrar till att lura kroppens immunförsvar och underlättar spridning av dottertumörer till andra delar av kroppen.

När vi slår ut signaleringen kan tumörcellerna inte längre påverka bindvävscellerna lika effektivt, och således minskar förekomsten av flera faktorer som gynnar tumörtillväxten. IL-1a kan därför vara en lovande kandidat att utforska vidare för framtida som ett läkemedel mot bukspottkörtelcancer.

The human pancreatic cancer cell line (SW 1990) was exposed to 0.2 μg/ml of octreotide, galanin or serotonin as single, double or triple combinations. The tumor cells were checked at 3, 6 and 12 hours. In order to determine the number of viable cancer cells, the MTT-assay was used. Proliferation, apoptosis and the expression of epidermal growth factor were detected with immunohistochemistry using the avidin-biotin complex method. In addition, apoptosis was also detected with (TUNEL) method. The primary antibodies used were proliferating cell nuclear antigen (PCNA), anti-poly (ADP-ribose) polymerase (PARP) and anti-human epidermal growth factor. Single treatment with octreotide or serotonin reduced, the number of viable cells and the proliferation index at all observation times. Galanin increased the number of viable cells and the proliferation index. Whereas double treatments containing octreotide reduced the number of viable cells, those containing galanin increased the number. The effect of single, double or triple treatment on the apoptotic index obtained with both TUNEL method and PARP expression varied depending on the combination and the observation time. Octreotide did not affect the tumor cell expression of EGF. Galanin and serotonin, on the other hand, increased the expression of EGF. Whereas triple combination increased the expression of EGF after 6 h, all the other double combinations decreased this expression. It has been concluded that treatment with a combination of octreotide and serotonin may be useful in clinical settings.