Activation Of Pancreatic Stellate Cells Research Articles

Human umbilical cord–derived mesenchymal stem cells improve chronic pancreatitis in rats via the AKT-mTOR-S6K1 signaling pathway

ABSTRACT Chronic pancreatitis (CP) is a progressive inflammatory disease. In clinical treatment, many patients cannot get a timely diagnosis and effective treatment due to the lack of early diagnosis indicators. Mesenchymal stem cells have immunomodulatory and anti-inflammatory effects, and have broad application prospects in treating auto-immune diseases and inflammatory diseases. This study aimed to clarify the mechanisms of human umbilical cord mesenchymal stem cells (HUCMSCs) in the treatment of CP. The rats were randomly divided into four groups, with six rats in each group: control group, CP group, CP + HUCMSCs–treated group I, and CP + HUCMSCs–treated group II. We evaluated the levels of inflammatory factors, fibrosis and apoptosis markers, detected the protein expression levels of AKT-mTOR-S6K1 and assessed histological changes of the pancreas. The results showed that HUCMSCs not only inhibited the secretion of inflammatory cytokines and activation of pancreatic stellate cells but also suppressed the apoptosis of acinar cells. Further investigation revealed that HUCMSCs noticeably suppressed the AKT-mTOR-S6K1 pathway in the pancreatic tissue of DBTC-induced CP. In addition, the therapeutic effect of HUCMSCs injected into the inferior vena cava and left gastric artery in the CP model was also observed, thus providing the basis for the clinical application of intervention measures.

Heat Shock Protein-90 Inhibition Alters Activation of Pancreatic Stellate Cells and Enhances the Efficacy of PD-1 Blockade in Pancreatic Cancer.

Pancreatic ductal adenocarcinoma (PDAC) has a prominent fibrotic stroma, which is a result of interactions between tumor, immune and pancreatic stellate cells (PSC), or cancer-associated fibroblasts (CAF). Targeting inflammatory pathways present within the stroma may improve access of effector immune cells to PDAC and response to immunotherapy. Heat shock protein-90 (Hsp90) is a chaperone protein and a versatile target in pancreatic cancer. Hsp90 regulates a diverse array of cellular processes of relevance to both the tumor and the immune system. However, to date the role of Hsp90 in PSC/CAF has not been explored in detail. We hypothesized that Hsp90 inhibition would limit inflammatory signals, thereby reprogramming the PDAC tumor microenvironment to enhance sensitivity to PD-1 blockade. Treatment of immortalized and primary patient PSC/CAF with the Hsp90 inhibitor XL888 decreased IL6, a key cytokine that orchestrates immune changes in PDAC at the transcript and protein level in vitro XL888 directly limited PSC/CAF growth and reduced Jak/STAT and MAPK signaling intermediates and alpha-SMA expression as determined via immunoblot. Combined therapy with XL888 and anti-PD-1 was efficacious in C57BL/6 mice bearing syngeneic subcutaneous (Panc02) or orthotopic (KPC-Luc) tumors. Tumors from mice treated with both XL888 and anti-PD-1 had a significantly increased CD8+ and CD4+ T-cell infiltrate and a unique transcriptional profile characterized by upregulation of genes associated with immune response and chemotaxis. These data demonstrate that Hsp90 inhibition directly affects PSC/CAF in vitro and enhances the efficacy of anti-PD-1 blockade in vivo.

Efficient Targeted Therapy for Pancreatic Cancer Using Nanosystem and Focusing on the Suppression of Pancreatic Stellate Cell Activation

Introduction: Pancreatic cancer is characterized by remarkable desmoplasia which causes poor drug delivery and resistance to anticancer therapy. Pancreatic stellate cells (PSCs) play a key role in construction of such tumor environment and enhance the malignancy of pancreatic cancer cells. We have previously reported PSC activation was suppressed by inhibiting autophagy of PSC using a lysosomal inhibitor, chloroquine (CQ). However, CQ requires high dosage to be effective in vivo. In this study, we developed nanoparticle-based drug delivery system (DDS) and evaluated its availability in the tumor-bearing mouse model. Methods: Poly lactic-co-glycolic acid (PLGA) was used as a DDS carrier. The PLGA nanoparticles were loaded with ICG (Nano-ICG) or CQ (Nano-CQ). The accumulation of Nano-ICG in pancreatic tumor was evaluated by in vivoimaging system (IVIS). The effects of CQ, Nano-CQ, or the combination of these agents and gemcitabine (GEM) on the activation of PSC and tumor growth were investigated in the orthotopic xenograft mouse model. Results: Nano-ICG showed pancreatic tumor-specific accumulation and persisted for more than one week after administration. No obvious accumulation was observed in other major organs including liver, kidney, and normal pancreatic tissue. The fraction of activated PSC was significantly decreased in Nano-CQ group compared to the control group. The combination of Nano-CQ and GEM showed the best ability to restrain tumor progression among all the groups. Conclusion: Our PLGA-based nanosystem was considered to be a promising DDS for the treatment of pancreatic cancer and nano-CQ could enhance the efficacy of anticancer drugs.

Novel Nonsecosteroidal Vitamin D Receptor Modulator Combined with Gemcitabine Enhances Pancreatic Cancer Therapy through Remodeling of the Tumor Microenvironment.

In a pancreatic tumor microenvironment, activated pancreatic stellate cells (PSCs) produce extracellular matrix (ECM) to form a barrier to drug penetration. Moreover, the interaction between cancer cells and activated PSCs promotes the tumor growth. Vitamin D receptor (VDR), as a key regulator to promote the recovery of PSCs to the resting state, is an attractive therapeutic target for pancreatic cancer. Herein, we reported the design and synthesis of 57 nonsecosteroidal VDR modulators based on the skeleton of phenyl-pyrrolyl pentane. Among them, compounds C4, I5, and I8 exhibited excellent VDR affinity and effective inhibition of the activation of PSCs, as well as potent suppression of the interaction between cancer cells and PSCs in vitro. In vivo, compound I5 combined with gemcitabine achieved efficacious antitumor activity without causing hypercalcemia. In conclusion, the compounds designed in our study can remodel the tumor microenvironment and are expected to be candidates for the treatment of pancreatic cancer.

The effects of nuclear factor-kappa B in pancreatic stellate cells on inflammation and fibrosis of chronic pancreatitis.

The activation of pancreatic stellate cells (PSCs) plays a critical role in the progression of pancreatic fibrosis. Nuclear factor‐kappa B (NF‐κB) is associated with chronic pancreatitis (CP). Previous evidence indicated that NF‐κB in acinar cells played a double‐edged role upon pancreatic injury, whereas NF‐κB in inflammatory cells promoted the progression of CP. However, the effects of NF‐κB in PSCs have not been studied. In the present study, using two CP models and RNAi strategy of p65 in cultured PSCs, we found that the macrophage infiltration and MCP‐1 expression were increased, and the NF‐κBp65 protein level was elevated. NF‐κBp65 was co‐expressed with PSCs. In vitro, TGF‐β1 induced overexpression of the TGF‐β receptor 1, phosphorylated TGF‐β1–activated kinase 1 (p‐TAK1) and NF‐κB in the PSCs. Moreover, the concentration of MCP‐1 in the supernatant of activated PSCs was elevated. The migration of BMDMs was promoted by the supernatant of activated PSCs. Further knockdown of NF‐κBp65 in PSCs resulted in a decline of BMDM migration, accompanied by a lower production of MCP‐1. These findings indicate that TGF‐β1 can induce the activation of NF‐κB pathway in PSCs by regulating p‐TAK1, and the NF‐κB pathway in PSCs may be a target of chronic inflammation and fibrosis.

Hic-5 is required for activation of pancreatic stellate cells and development of pancreatic fibrosis in chronic pancreatitis

Accumulated evidence suggests that activated pancreatic stellate cells (PSCs) serve as the main source of the extracellular matrix proteins accumulated under the pathological conditions leading to pancreatic fibrosis in chronic pancreatitis (CP). However, little is known about the mechanisms of PSC activation. PSCs have morphologic and functional similarities to hepatic stellate cells, which are activated by hydrogen peroxide-inducible clone-5 (Hic-5), a TGF-β1-induced protein. In this study, we investigated whether Hic-5 activates PSCs, which promote pancreatic fibrosis development in CP. Hic-5-knockout and wild type mice were subjected to caerulein injection to induce CP. Hic-5 expression was strongly upregulated in activated PSCs from human CP tissue and from mouse pancreatic fibrosis in caerulein-induced CP. Hic-5 deficiency significantly attenuated mouse pancreatic fibrosis and PSC activation in the experimental murine CP model. Mechanistically, Hic-5 knock down significantly inhibited the TGF-β/Smad2 signaling pathway, resulting in reduced collagen production and α-smooth muscle actin expression in the activated PSCs. Taken together, we propose Hic-5 as a potential marker of activated PSCs and a novel therapeutic target in CP treatment.

ASIC1 inhibition impairs the proliferation and migration of pancreatic stellate cells induced by pancreatic cancer cells.

Activated pancreatic stellate cells (PSCs) with an increased proliferation and migration ability are the partners in crime with pancreatic cancer cells. Acid-sensing ion channel 1 (ASIC1) is expressed in pancreatic cancer and PSCs, and especially, it mediates the activation of PSCs. However, whether ASIC1 is involved in pancreatic cancer cells-induced biological behavior re-educating of PSCs is unclear. In this study, the change of ASIC1 expression in PSCs and pancreatic cancer Panc-1 cells after in-direct co-culture was detected by western blotting, and the proliferation and migration of PSCs with ASIC1 knockdown under Panc-1 cells-conditioned medium (Panc-1-CM) was assessed. The results showed that pancreatic cancer cells induced ASIC1 overexpression, and the enhanced proliferation and migration of PSCs was weakened by ASIC1 inhibition. In addition, the extracellular signal-regulated kinase (ERK) expression in PSCs remained stable, but the phosphorylated ERK (p-ERK) expression in PSCs treated with Panc-1-CM increased, which was suppressed by ASIC1 knockdown. These results indicate that ASIC1 participates in the regulation of PSCs proliferation and migration induced by cancer cells via the ERK pathway, and ASIC1 inhibition may be beneficial to pancreatic cancer treatment.

Chronic Pancreatitis and the Development of Pancreatic Cancer.

Pancreatitis is a fibro-inflammatory disorder of the pancreas that can occur acutely or chronically as a result of the activation of digestive enzymes that damage pancreatic cells, which promotes inflammation. Chronic pancreatitis with persistent fibro-inflammation of the pancreas progresses to pancreatic cancer, which is the fourth leading cause of cancer deaths across the globe. Pancreatic cancer involves cross-talk of inflammatory, proliferative, migratory, and fibrotic mechanisms. In this review, we discuss the role of cytokines in the inflammatory cell storm in pancreatitis and pancreatic cancer and their role in the activation of SDF1α/CXCR4, SOCS3, inflammasome, and NF-κB signaling. The aberrant immune reactions contribute to pathological damage of acinar and ductal cells, and the activation of pancreatic stellate cells to a myofibroblast-like phenotype. We summarize several aspects involved in the promotion of pancreatic cancer by inflammation and include a number of regulatory molecules that inhibit that process.

Gamma-delta T cells stimulate IL-6 production by pancreatic stellate cells in pancreatic ductal adenocarcinoma

IntroductionThe immunosuppressive tumor microenvironment promotes progression of pancreatic ductal adenocarcinoma (PDAC). γδ T cells infiltrate the pancreatic tumor stroma and support tumorigenesis through αβ T cell inhibition. Pancreatic stellate cell (PSC) activation contributes to pancreatic fibrosis in PDAC, limiting the delivery and efficacy of therapeutic agents. Whether γδ T cells have direct effects on PSC activation is unknown.MethodsIn this study, we analyzed tumor tissue from 68 patients with PDAC and determined the frequency and location of γδ T cells using immunohistochemistry and immunofluorescence. PDAC samples from the TCGA database with low and high TRGC2 expression were correlated with the expression of extracellular matrix genes. Further, PSCs were isolated from pancreatic tumor tissue and co-cultured with γδ T cells for 48 hours and cytokine production was measured using a cytometric bead array.Resultsγδ T cells infiltrated the pancreatic tumor stroma and were located in proximity to PSCs. A high infiltration of γδ T cells was associated with increased expression of several extracellular matrix genes in human PDAC. In vitro, γδ T cells stimulated IL-6 production by PDAC-derived PSCs.Conclusionγδ T cells activated PSCs and modulation of this interaction may enhance the efficacy of combinational therapies in human PDAC.

Berberine attenuates severity of chronic pancreatitis and fibrosis via AMPK-mediated inhibition of TGF-β1/Smad signaling and M2 polarization

Berberine (BR) acts as an AMP-activated protein kinase (AMPK) activator which possesses antioxidant and anti-inflammatory properties. In this study, we have investigated the effects of BR against cerulein-induced chronic pancreatitis (CP) via inhibition of TGF-β/Smad signaling and M2 macrophages polarization in AMPK dependent manner. Cerulein-induced CP mice were treated with BR (3 and 10 mg/kg), intraperitoneally every day for 21 days. Our results indicated that, BR treatment (10 mg/kg) significantly reduced oxidative-nitrosative stress, histological alterations, inflammatory cells infiltration and collagen deposition in pancreatic tissue. BR treatment also prevented cerulein-induced pancreatic stellate cells (PSCs) activation and extracellular matrix (ECM) deposition via downregulation of α-SMA, collagen1a, collagen3a and fibronectin expression. Mechanistically, treatment with BR significantly activated AMPK signaling as compared to cerulein-challenged mice. Further, administration of BR also inhibited TGF-β/Smad signaling and macrophages polarization in cerulein-induced CP in-vivo models and TGF-β1 stimulated RAW 264.7 macrophages in-vitro. Together, our results strongly suggest that BR treatment protected against cerulein-induced CP and associated fibrosis progression by inhibiting TGF-β1/Smad signaling and M2 macrophages polarization in an AMPK dependent manner.

Targeting the CBP/β-Catenin Interaction to Suppress Activation of Cancer-Promoting Pancreatic Stellate Cells.

Background: Although cyclic AMP-response element binding protein-binding protein (CBP)/β-catenin signaling is known to promote proliferation and fibrosis in various organ systems, its role in the activation of pancreatic stellate cells (PSCs), the key effector cells of desmoplasia in pancreatic cancer and fibrosis in chronic pancreatitis, is largely unknown. Methods: To investigate the role of the CBP/β-catenin signaling pathway in the activation of PSCs, we have treated mouse and human PSCs with the small molecule specific CBP/β-catenin antagonist ICG-001 and examined the effects of treatment on parameters of activation. Results: We report for the first time that CBP/β-catenin antagonism suppresses activation of PSCs as evidenced by their decreased proliferation, down-regulation of “activation” markers, e.g., α-smooth muscle actin (α-SMA/Acta2), collagen type I alpha 1 (Col1a1), Prolyl 4-hydroxylase, and Survivin, up-regulation of peroxisome proliferator activated receptor gamma (Ppar-γ) which is associated with quiescence, and reduced migration; additionally, CBP/β-catenin antagonism also suppresses PSC-induced migration of cancer cells. Conclusion: CBP/β-catenin antagonism represents a novel therapeutic strategy for suppressing PSC activation and may be effective at countering PSC promotion of pancreatic cancer.

Thromboxane A2 receptor contributes to the activation of rat pancreatic stellate cells induced by 8-epi-prostaglandin F2α.

BackgroundPancreatic stellate cells (PSCs) activation plays a critical role in the development of chronic pancreatitis. Previous studies confirmed that thromboxane A2 receptor (TxA2r) was overexpressed in activated PSCs in rats. The purpose of this study was to investigate the role of TxA2r in the activation of PSCs induced by 8-epi-prostaglandin F2α (8-epi-PGF2α).MethodsTxA2r expression in both quiescent and activated PSCs was detected by immunocytochemistry and immunoblot assay. Isolated PSCs were treated with 8-epi-PGF2α (10−6, 10−7, 10−8 mol/L) for 48 h, and SQ29548 (10−4, 10−6, and 10−7 mol/L), a TxA2r-specific antagonist for 48 h, respectively, to identify the drug concentration with the best biological effect and the least cytotoxicity. Then isolated PSCs were treated with SQ29548 (10−4 mol/L) for 2 h, followed by 10−7 mol/L 8-epi-PGF2α for 48 h. Real-time polymerase chain reaction was performed to detect the messenger RNA (mRNA) levels of α-smooth muscle actin (α-SMA) and collagen I. Comparisons between the groups were performed using Student's t test.ResultsTxA2r was up-regulated in activated PSCs in vitro compared with quiescent PSCs (all P < 0.001). Compared with the control group, different concentrations of 8-epi-PGF2α significantly increased mRNA levels of α-SMA (10−6 mol/L: 2.23 ± 0.18 vs. 1.00 ± 0.07, t = 10.70, P < 0.001; 10−7 mol/L: 2.91 ± 0.29 vs. 1.01 ± 0.08, t = 10.83, P < 0.001; 10−8 mol/L, 1.67 ± 0.07 vs. 1.00 ± 0.08, t = 11.40, P < 0.001) and collagen I (10−6 mol/L: 2.68 ± 0.09 vs. 1.00 ± 0.07, t = 24.94, P < 0.001; 10−7 mol/L: 2.12 ± 0.29 vs. 1.01 ± 0.12, t = 6.08, P < 0.001; 10−8 mol/L: 1.46 ± 0.15 vs. 1.00 ± 0.05, t = 4.93, P = 0.008). However, different concentrations of SQ29548 all significantly reduced the expression of collagen I (10−4 mol/L: 0.55 ± 0.07 vs. 1.00 ± 0.07, t = 10.47, P < 0.001; 10−6 mol/L: 0.56 ± 0.10 vs. 1.00 ± 0.07, t = 6.185, P < 0.001; 10−7 mol/L: 0.27 ± 0.04 vs. 1.00 ± 0.07, t = 15.41, P < 0.001) and α-SMA (10−4 mol/L: 0.06 ± 0.01 vs. 1.00 ± 0.11, t = 15.17, P < 0.001; 10−6 mol/L: 0.28 ± 0.03 vs. 1.00 ± 0.11, t = 11.29, P < 0.001; 10−7 mol/L: 0.14 ± 0.04 vs. 1.00 ± 0.11, t = 12.86, P < 0.001). After being treated with SQ29548 (10−4 mol/L) and then 8-epi-PGF2α (10−7 mol/L), the mRNA levels of α-SMA (0.20 ± 0.08 vs. 1.00 ± 0.00, t = 17.46, P < 0.001) and collagen I (0.69 ± 0.13 vs. 1.00 ± 0.00, t = 4.20, P = 0.014) in PSCs were significantly lower than those of the control group.ConclusionsThe results show that 8-epi-PGF2α promoted PSCs activation, while SQ29548 inhibited PSCs activation induced by 8-epi-PGF2α. The result indicated that TxA2r plays an important role during PSC activation and collagen synthesis induced by 8-epi-PGF2αin vitro. This receptor may provide a potential target for more effective antioxidant therapy for pancreatic fibrosis.

Saikosaponin A inhibits the activation of pancreatic stellate cells by suppressing autophagy and the NLRP3 inflammasome via the AMPK/mTOR pathway

Pancreatic stellate cells (PSCs) are the main effector cells in the development of pancreatic fibrosis. Finding substances that inhibit PSC activation is an important approach to inhibiting pancreatic fibrosis. Saikosaponin A (SSa) has numerous pharmacological activities, but its effect on PSCs remains unknown. This study was conducted to explore the effects of SSa on PSC activation in cultured rat PSCs. Cell viability, proliferation, migration and apoptosis were evaluated by MTT assays, the iCELLigence System, Transwell assays and flow cytometry. Markers of PSC activation, autophagy and the NLRP3 inflammasome were measured by real-time PCR, immunofluorescence and western blotting. Rapamycin and phenformin hydrochloride were used to determine the effect of SSa via the AMPK/mTOR pathway. The results showed that SSa suppressed PSC viability, proliferation, and migration and promoted apoptosis. SSa inhibited PSC activation, restrained PSC autophagy and suppressed the NLRP3 inflammasome. In addition, there was interaction between autophagy and the NLRP3 inflammasome during SSa inhibition of PSCs. Moreover, promotion of p-AMPK increased autophagy and the NLRP3 inflammasome. Inhibition of p-mTOR increased autophagy and decreased the NLRP3 inflammasome. Our results indicated that SSa inhibited PSC activation by inhibiting PSC autophagy and the NLRP3 inflammasome via the AMPK/mTOR pathway. These findings provide a theoretical basis for the use of SSa to treat pancreatic fibrosis and further suggest that targeting autophagy and the NLRP3 inflammasome may provide new strategies for the treatment of pancreatic fibrosis.

A novel pancreatic tumour and stellate cell 3D co-culture spheroid model

BackgroundPancreatic ductal adenocarcinoma is a devastating disease with poor outcome, generally characterized by an excessive stroma component. The purpose of this study was to develop a simple and reproducible in vitro 3D-assay employing the main constituents of pancreatic ductal adenocarcinoma, namely pancreatic stellate and cancer cells.MethodA spheroid assay, directly co-culturing human pancreatic stellate cells with human pancreatic tumour cells in 3D was established and characterized by electron microscopy, immunohistochemistry and real-time RT-PCR. In order to facilitate the cell type-specific crosstalk analysis by real-time RT-PCR, we developed a novel in vitro 3D co-culture model, where the participating cell types were from different species, human and mouse, respectively. Using species-specific PCR primers, we were able to investigate the crosstalk between stromal and cancer cells without previous cell separation and sorting.ResultsWe found clear evidence for mutual influence, such as increased proliferation and a shift towards a more mesenchymal phenotype in cancer cells and an activation of pancreatic stellate cells towards the myofibroblast phenotype. Using a heterospecies approach, which we coined virtual sorting, confirmed the findings we made initially in the human-human spheroids.ConclusionsWe developed and characterized different easy to set up 3D models to investigate the crosstalk between cancer and stroma cells for pancreatic cancer.

Legumain promotes fibrogenesis in chronic pancreatitis via activation of transforming growth factor β1.

Chronic pancreatitis (CP) is a major risk factor for pancreatic cancer; however, little is known about the pathogenic mechanisms underlying the development of CP. Legumain (Lgmn) has been linked to some chronic inflammatory diseases. The present study investigated the role of legumain in pancreatic fibrogenesis. We induced CP in wild type C57BL6 (WT), Lgmn-deficient (Lgmn-/-), Lgmnflox/flox and Lgmnflox/flox × LysMCre mice by intraperitoneal injection of caerulein for 4weeks. Pancreata were collected and analyzed by quantitative reverse transcription polymerase chain reaction, Western blotting, and histology. Pancreatic stellate cells and macrophages were isolated and studied using immunofluorescence, gelatin zymography, and enzyme-linked immunosorbent assay. The effects of inhibition of legumain were investigated in vivo by administration of the specific legumain inhibitor, RR-11a. Legumain was found to be upregulated in the serum and pancreatic tissues of mice with caerulein-induced CP. Mice with global and macrophage-specific legumain deficiency exhibited significantly reduced development of pancreatic fibrosis compared with control mice, based on pancreas size, histology, and expression of fibrosis-associated genes. Our results indicate that legumain promotes activation of pancreatic stellate cells and increases synthesis of extracellular matrix proteins via activation of matrix metalloproteinase-2(MMP-2), which hydrolyzes the transforming growth factor-β1 (TGF-β1) precursor to form active TGF-β1. Administration of RR-11a markedly attenuated pancreatic fibrosis in mice with CP. Deficiency or inhibition of legumain significantly reduces the severity of pancreatic fibrosis by suppressing activation of the TGF-β1 precursor. Our results highlight the potential of legumain as a novel therapeutic target for CP. KEY MESSAGES: • Legumain expression was markedly upregulated in CP mice. • Deletion of legumain attenuated pancreatic fibrosis in CP mice. • Legumain promotes fibrosis via MMP-2 activation, which hydrolyzed the TGF-β1 precursor to the active form. • Legumain is a potential therapeutic target for the management of CP.

Hypoxia Increases β-Cell Death by Activating Pancreatic Stellate Cells within the Islet.

BackgroundHypoxia can occur in pancreatic islets in type 2 diabetes mellitus. Pancreatic stellate cells (PSCs) are activated during hypoxia. Here we aimed to investigate whether PSCs within the islet are also activated in hypoxia, causing β-cell injury.MethodsIslet and primary PSCs were isolated from Sprague Dawley rats, and cultured in normoxia (21% O2) or hypoxia (1% O2). The expression of α-smooth muscle actin (α-SMA), as measured by immunostaining and Western blotting, was used as a marker of PSC activation. Conditioned media (hypoxia-CM) were obtained from PSCs cultured in hypoxia.ResultsIslets and PSCs cultured in hypoxia exhibited higher expressions of α-SMA than did those cultured in normoxia. Hypoxia increased the production of reactive oxygen species. The addition of N-acetyl-L-cysteine, an antioxidant, attenuated the hypoxia-induced PSC activation in islets and PSCs. Islets cultured in hypoxia-CM showed a decrease in cell viability and an increase in apoptosis.ConclusionPSCs within the islet are activated in hypoxia through oxidative stress and promote islet cell death, suggesting that hypoxia-induced PSC activation may contribute to β-cell loss in type 2 diabetes mellitus.

Curcumin inhibits pancreatic cancer cell invasion and EMT by interfering with tumor‑stromal crosstalk under hypoxic conditions via the IL‑6/ERK/NF‑κB axis

Hypoxic microenvironment and pancreatic stellate cells (PSCs) play important roles in pancreatic cancer progression. PSCs secrete a number of soluble factors, such as interleukin (IL)‑6, to facilitate cancer metastasis. Our previous study revealed that curcumin inhibited the invasive ability of pancreatic cancer cells by modulating epithelial‑to‑mesenchymal transition (EMT)‑related factors. However, whether curcumin could suppress tumor‑stromal crosstalk in pancreatic cancer and the underlying mechanisms have yet to be fully elucidated. The aim of the present study was to evaluate whether curcumin could affect pancreatic cancer cell invasion and EMT by interfering with tumor‑stromal interaction under hypoxic conditions. The PSCs were treated with curcumin under hypoxic conditions. The activation of PSCs was detected by testing the expression of α‑smooth muscle actin by western blotting and immunofluorescence analysis. The wound healing assay was used to evaluate the migratory potential of PSCs. The secretion and expression of IL‑6 by PSCs was detected by ELISA and reverse transcription‑quantitative PCR (RT‑qPCR) analysis. BxPC‑3 and Panc‑1 cells were treated with PSC‑conditioned media (PSC‑CM), IL‑6, IL‑6‑neutralizing antibody or curcumin under conditions of normoxia or hypoxia. Transwell invasion assay was used to examine the invasive potential of pancreatic cancer cells. The activation of phosphorylated (p‑) extracellular signal‑regulated kinase (ERK) and p‑nuclear factor (NF)‑κB were measured by western blot analysis. The expression of EMT‑related genes at the mRNA and protein levels was detected by RT‑qPCR and western blot analysis, respectively. The results of the present study demonstrated that curcumin inhibited the activation and migration of PSCs under hypoxic conditions. Curcumin also suppressed the secretion and expression of IL‑6 in PSCs. In addition, curcumin and IL‑6‑neutralizing antibody treatment suppressed PSC‑CM‑modulated pancreatic cancer invasion, EMT and the changes in the expression of E‑cadherin, vimentin and matrix metallopeptidase‑9. Furthermore, the increase in the levels of p‑ERK and p‑NF‑κB induced by PSC‑CM could be counterbalanced by both curcumin and IL‑6‑neutralizing antibody treatment under hypoxic conditions. Taken together, these data indicate that curcumin plays an important role in suppressing tumor‑stromal crosstalk and pancreatic cancer metastasis by inhibiting the IL‑6/ERK/NF‑κB axis. Blocking the IL‑6/ERK/NF‑κB axis by curcumin may be a promising therapeutic strategy for the treatment of pancreatic cancer.

Abstract B39: Regulation and function of IL-1b in immune modulation of pancreatic cancer

Abstract Pancreatic intraepithelial neoplasms (PanINs) are well-defined precursor lesions of pancreatic ductal adenocarcinoma (PDA). The initiation and progression of PanINs is marked by dynamic stromal reconstruction and localized acute inflammation. Using an orthotopic transplantation model of early and advanced pancreatic neoplasia in immunocompetent recipient mice, we have uncovered a crucial role for the cytokine IL-1b in KRasG12D-driven PanIN evolution. Tumor cell-derived IL-1b¢ was found to be critical for shaping the protumorigenic PanIN microenvironment by promoting activation of quiescent pancreatic stellate cells and establishing an immunosuppressive milieu mediated by M2 macrophages, MDSCs and CD1dhiCD5+ regulatory B cells. Furthermore, loss of IL-1 signaling in tumor stroma activates the cytotoxic T-cell immune response, significantly attenuates PanIN growth and confers survival advantage to PDAC-bearing mice. Tumor cell expression of IL-1b in vivo is driven by upregulation of TLR4 signaling and activation of the NLRP3 inflammasome. KrasG12D enhances surface TLR4 expression, sensitizing transformed cells to TLR4 ligands in the microenvironment, including the pancreatic microbiome. Collectively, our study describes a complex tumor-stromal interplay orchestrated by the TLR4-NLRP3-IL-1b signaling axis, which is critical for shaping the tumor microenvironment and driving pancreatic tumorigenesis. Citation Format: Shipra Das, Sandra Vogt, Christina Hadju, Dafna Bar-Sagi. Regulation and function of IL-1b in immune modulation of pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr B39.

Identification of irisin as a therapeutic agent that inhibits oxidative stress and fibrosis in a murine model of chronic pancreatitis

BackgroundAbnormal activation of pancreatic stellate cells (PSCs) plays a crucial role in the pathogenesis of chronic pancreatitis (CP). Irisin, an exercise-induced hormone, has been shown to mitigate liver fibrosis by inhibiting the activation of hepatic stellate cells. However, the effect of irisin in CP has not been evaluated. MethodsThis study aimed to determine whether irisin is protective in CP. CP was induced by 6 IP injections of cerulein (50 μg/kg/body weight). HPSCs were treated with 5 ng/ml TGF-β1 as in vitro experiment. ResultsOur results showed that repeated cerulein injection induced severe pancreatic injury and fibrosis in mice and the serum irisin level in cerulein-treated mice decreased as in CP patients. Excessive oxidative and ER stress was also present in the pancreas of cerulein-treated mice. Irisin treatment significantly alleviated pancreatic injury and fibrosis, which was associated with reduced oxidative and ER stress. In cultured PSCs, irisin directly inhibited TGF-β-induced α-SMA and collagen I expression. This effect appears to be mediated through downregulation of kindlin-2 and inhibition of the SMAD2/3 pathway. ConclusionsIrisin alleviated pancreatic injury and fibrosis, which was associated with reduced oxidative and ER stress. Thus, irisin may offer therapeutic potential for patients with CP.

Tumor Cell-Derived IL1β Promotes Desmoplasia and Immune Suppression in Pancreatic Cancer.

Pancreatic ductal adenocarcinoma (PDA) is an aggressive malignancy typified by a highly stromal and weakly immunogenic tumor microenvironment that promotes tumor evolution and contributes to therapeutic resistance. Here, we demonstrate that PDA tumor cell-derived proinflammatory cytokine IL1β is essential for the establishment of the protumorigenic PDA microenvironment. Tumor cell-derived IL1β promoted the activation and secretory phenotype of quiescent pancreatic stellate cells and established an immunosuppressive milieu mediated by M2 macrophages, myeloid-derived suppressor cells, CD1dhiCD5+ regulatory B cells, and Th17 cells. Loss of tumor cell-derived IL1 signaling in tumor stroma enabled intratumoral infiltration and activation of CD8+ cytotoxic T cells, attenuated growth of pancreatic neoplasia, and conferred survival advantage to PDA-bearing mice. Accordingly, antibody-mediated neutralization of IL1β significantly enhanced the antitumor activity of α-PD-1 and was accompanied by increased tumor infiltration of CD8+ T cells. Tumor cell expression of IL1β in vivo was driven by microbial-dependent activation of toll-like receptor 4 (TLR4) signaling and subsequent engagement of the NLRP3 inflammasome. Collectively, these findings identify a hitherto unappreciated role for tumor cell-derived IL1β in orchestrating an immune-modulatory program that supports pancreatic tumorigenesis. SIGNIFICANCE: These findings identify a new modality for immune evasion in PDA that depends on IL1β production by tumor cells through TLR4-NLRP3 inflammasome activation. Targeting this axis might provide an effective PDA therapeutic strategy.