Current update of cytokines in pancreatic cancer: pathogenic mechanisms, clinical indication, and therapeutic values

Effect of chemokine CXCL14 on in vitro angiogenesis of human hepatocellular carcinoma cells

The study was designed to investigate the effect of chemokine CXCL14 on in vitro angiogenesis of human hepatocellular carcinoma (HCC) cells. CXCL14 mRNA expression in HCC tissue samples and adjacent tissue samples was detected by quantitative reverse transcription polymerase chain reaction (qRT-PCR). CXCL14 mRNA and protein expression in human normal hepatocyte HL-7702 and HCC cell line HepG2 were detected by qRT-PCR and western blot. In HepG2 cell line, the expression of vascular endothelial growth factor (VEGF) was detected by enzyme-linked immunosorbent assay method, cell viability was detected by CCK-8, cell proliferation was detected by colony formation assay, and cell migration as well as invasion ability was detected by Transwell assay. Moreover, human umbilical vein endothelial cell (HUVEC) tube formation assay was carried out to determine the cell ability of angiogenesis. Results showed that the overexpression of CXCL14 could inhibit angiogenesis, proliferation, migration, and invasion abilities of HCC cells.Highlights CXCL14 is lowly expressed in hepatocellular carcinoma tissues and cells. CXCL14 overexpression inhibits the angiogenesis of hepatocellular carcinoma cells. CXCL14 overexpression inhibits proliferation, invasion, and migration of hepatocellular carcinoma cells.

Methylation of immune-regulatory cytokine genes and pancreatic cancer outcomes

Aim: Given the immunosuppressive nature of pancreatic cancer, we investigated the relationship between epigenetic modification of immune-regulatory cytokine genes and pancreatic cancer outcomes. Materials & methods: We evaluated DNA methylation of 184 pancreatic tumor samples from The Cancer Genome Atlas for 111 CpG loci in seven cytokine genes: IL10, IL6, IL8, TGFβ1, TGFβ2, TGFβ3 and TNF. We used Cox regression to evaluate the associations between methylation and overall survival, disease-specific survival and disease progression (α = 0.05). Results: Poorer survival was associated with increased methylation in fifteen CpG probes in TGFβ1, TGFβ2, TGFβ3 and TNF. We also detected improved outcomes for three loci in IL10, IL8 and IL6. Conclusion: Epigenetic regulation of cytokine-related gene expression may be associated with pancreatic cancer outcomes.

Paraneoplastic β Cell Dedifferentiation in Nondiabetic Patients with Pancreatic Cancer

CONTEXT

Beta-cell dedifferentiation was recently proposed as a mechanism of β-cell dysfunction, but whether it can be a trigger of β-cell failure preceding hyperglycemia in humans is uncertain. Pancreatic cancer can cause new-onset diabetes, yet the underlying mechanism is unknown.

OBJECTIVE

To investigate whether β-cell dedifferentiation is present in nondiabetic pancreatic ductal adenocarcinoma (PDAC) patients, we examined pancreatic islets from 15 nondiabetic patients with benign tumors (control) and 15 nondiabetic PDAC patients.

DESIGN

We calculated the number of hormone-negative endocrine cells and evaluated important markers of β-cell dedifferentiation and function in the paraneoplastic islets. We assessed tumor-related inflammatory changes under the pancreatic cancer microenvironment and their influence on β-cell identity.

RESULTS

We found nearly 10% of nonhormone expressing endocrine cells in nondiabetic PDAC subjects. The PDAC islets were dysfunctional, evidenced by low expression of Glucose transporter 2 (GLUT2) and Urocortin3 (UCN3), and concomitant upregulation of Aldehyde Dehydrogenase 1 Family Member A3 (ALDH1A3) expression and proinsulin accumulation. Pancreatic cancer caused paraneoplastic inflammation with enhanced tissue fibrosis, monocytes/macrophages infiltration, and elevated inflammatory cytokines. Moreover, we detected β-cell dedifferentiation and defects in GSIS in islets exposed to PANC-1 (a cell line established from a pancreatic carcinoma of ductal origin from a 56-year-old Caucasian male)-conditioned medium. In a larger cohort, we showed high prevalence of new-onset diabetes in PDAC subjects, and fasting blood glucose (FBG) was found to be an additional useful parameter for early diagnosis of PDAC.

CONCLUSIONS

Our data provide a rationale for β-cell dedifferentiation in the pathogenesis of pancreatic cancer-associated diabetes. We propose that β-cell dedifferentiation can be a trigger for β-cell failure in humans, before hyperglycemia occurs.

Novel TREM-1 Inhibitors Attenuate Tumor Growth and Prolong Survival in Experimental Pancreatic Cancer

Pancreatic cancer (PC) is a highly lethal cancer with an urgent need to expand the limited treatment options for patients. Tumor-associated macrophages (TAMs) promote tumor aggressiveness and metastasis. High expression of triggering receptor expressed on myeloid cells 1 (TREM-1) on TAMs directly correlates with poor survival in patients with non-small cell lung cancer (NSCLC). We have previously hypothesized that blockade of TREM-1 could be a promising therapeutic strategy to treat cancer and shown that the novel, ligand-independent TREM-1 inhibitory peptides rationally designed using the signaling chain homooligomerization (SCHOOL) strategy suppress NSCLC growth in vivo. Here, we evaluated the therapeutic potential of these inhibitors in three human PC xenograft mouse models. Administration of SCHOOL peptides resulted in a strong antitumor effect achieving an optimal treatment/control (T/C) value of 19% depending on the xenograft and formulation used and persisting even after treatment was halted. The effect correlated significantly with increased survival and suppressed TAM infiltration. The peptides were well-tolerated when deployed either in free form or formulated into lipopeptide complexes for peptide half-life extension and targeted delivery. Finally, blockade of TREM-1 significantly reduced serum levels of interleukin (IL)-1α, IL-6, and macrophage colony-stimulating factor (M-CSF), but not vascular endothelial growth factor, suggesting M-CSF-dependent antitumor mechanisms. Collectively, these promising data suggest that SCHOOL TREM-1-specific peptide inhibitors have a cancer type independent, therapeutically beneficial antitumor activity and can be potentially used as a stand-alone therapy or as a component of combinational therapy for PC, NSCLC, and other solid tumors.

Improving Chimeric Antigen Receptor-Modified T Cell Function by Reversing the Immunosuppressive Tumor Microenvironment of Pancreatic Cancer

The adoptive transfer of T cells redirected to tumor-associated antigens via transgenic expression of chimeric antigen receptors (CARs) has produced tumor responses, even in patients with refractory diseases. To target pancreatic cancer, we generated CAR T cells directed against prostate stem cell antigen (PSCA) and demonstrated specific tumor lysis. However, pancreatic tumors employ immune evasion strategies such as the production of inhibitory cytokines, which limit CAR T cell persistence and function. Thus, to protect our cells from the immunosuppressive cytokine IL-4, we generated an inverted cytokine receptor in which the IL-4 receptor exodomain was fused to the IL-7 receptor endodomain (4/7 ICR). Transgenic expression of this molecule in CAR-PSCA T cells should invert the inhibitory effects of tumor-derived IL-4 and instead promote T cell proliferation. We now demonstrate the suppressed activity of CAR T cells in tumor-milieu conditions and the ability of CAR/ICR T cells to thrive in an IL-4-rich microenvironment, resulting in enhanced antitumor activity. Importantly, CAR/ICR T cells remained both antigen and cytokine dependent. These findings support the benefit of combining the 4/7 ICR with CAR-PSCA to treat pancreatic cancer, a PSCA-expressing tumor characterized by a dense immunosuppressive environment rich in IL-4.

Role of microenvironmental periostin in pancreatic cancer progression

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a prominent desmoplastic reaction. Pancreatic stellate cells (PSCs) are the principal effector cells responsible for stroma production. Aberrant up-regulation of periostin expression has been reported in activated PSCs. In this study, we investigated the role of periostin and the mechanisms underlying its aberrant upregulation in PDAC. We used lentiviral shRNA and human recombinant periostin protein to down and up regulate periostin expression in vitro. Specific oncogenic signaling pathways such as EGFR-Akt and EGFR-Erk-c-Myc were assessed in vitro and in vivo. Tissue microarray immunohistochemical assays including 80 pancreatic cancer tissues and paired normal tissues were used to understand the function relationship between periostin expression and PDAC pathologic stage and overall survival. We found that periostin was strongly expressed in PSCs and the stroma of PDAC tumors. We also observed a significant decrease in proliferation, metastasis, and clonality of pancreatic cancer cells when co-cultured with supernatant of periostin shRNA-transfected PSCs. Specifically, the biological behavior of periostin correlated with EGFR-Akt and EGER-Erk-c-Myc signaling pathways. Moreover, increased periostin expression significantly associated with advanced disease stage and decreased survival rate in PDAC patients. Together, our findings provide novel insights into the role of microenvironmental periostin in pancreatic cancer progression, and periostin may serve as a prognostic biomarker for PDAC.

Macrophage migration inhibitory factor induces epithelial to mesenchymal transition, enhances tumor aggressiveness and predicts clinical outcome in resected pancreatic ductal adenocarcinoma

MIF is a proinflammatory cytokine and is implicated in cancer. A higher MIF level is found in many human cancer and cancer-prone inflammatory diseases, including chronic pancreatitis and pancreatic cancer. We tested the hypothesis that MIF contributes to pancreatic cancer aggressiveness and predicts disease outcome in resected cases. Consistent with our hypothesis we found that an elevated MIF mRNA expression in tumors was significantly associated with poor outcome in resected cases. Multivariate Cox-regression analysis further showed that MIF is independently associated with patients' survival (HR = 2.26, 95% CI = 1.17-4.37, p = 0.015). Mechanistic analyses revealed that MIF overexpression decreased E-cadherin and increased vimentin mRNA and protein levels in pancreatic cancer cell lines, consistent with the features of epithelial-to-mesenchymal transition (EMT). Furthermore, MIF-overexpression significantly increased ZEB1/2 and decreased miR-200b expression, while shRNA-mediated inhibition of MIF increased E-cadherin and miR-200b expression, and reduced the expression of ZEB1/2 in Panc1 cells. Re-expression of miR-200b in MIF overexpressing cells restored the epithelial characteristics, as indicated by an increase in E-cadherin and decrease in ZEB1/2 and vimentin expression. A reduced sensitivity to the chemotherapeutic drug, gemcitabine, occurred in MIF-overexpressing cells. Indicative of an increased malignant potential, MIF over-expressing cells showed significant increase in their invasion ability in vitro, and tumor growth and metastasis in an orthotopic xenograft mouse model. These results support a role of MIF in disease aggressiveness, indicating its potential usefulness as a candidate target for designing improved treatment in pancreatic cancer.

Inflammatory cytokines regulate the expression of glycosyltransferases involved in the biosynthesis of tumor-associated sialylated glycans in pancreatic cancer cell lines

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is characterized by an abundant stroma containing several pro-inflammatory cytokines, which are described to modulate the expression of important genes related to tumor promotion and progression. In the present work we have investigated the potential role of these cytokines in the biosynthesis of tumor-associated carbohydrate antigens such as sialyl-Lewis(x) (SLe(x)) through the regulation of specific glycosyltransferase genes.

METHODS

Two human PDAC cell lines MDAPanc-3 and MDAPanc-28 were treated with pro-inflammatory cytokines IL-1β, TNFα, IL-6 or IL-8, and the content of tumor-associated carbohydrate antigens at the cell membrane was analyzed by flow cytometry. In addition, variation in the mRNA expression of sialyltransferase (ST) and fucosyltransferase (FUT) genes, which codify for the ST and FucT enzymes involved in the carbohydrate antigens' biosynthesis, was determined. The inflammatory microenvironment of PDAC tissues and the expression of Lewis-type antigens were analyzed by immunohistochemistry to find a possible correlation between inflammation status and the presence of tumor-associated carbohydrate antigens.

RESULTS

IL-1β stimuli increased SLe(x) and α2,6-sialic acid levels in MDAPanc-28 cells and enhanced the mRNA levels of ST3GAL3-4 and FUT5-7, which codify for ST and FucT enzymes related to SLe(x) biosynthesis, and of ST6GAL1. IL-6 and TNFα treatments increased the levels of SLe(x) and Le(y) antigens in MDPanc-3 cells and, similarly, the mRNA expression of ST3GAL3-4, FUT1-2 and FUT6, related to these Lewis-type antigens' biosynthesis, were increased. Most PDAC tissues stained for SLe(x) and SLe(a) and tended to be expressed in the tumor samples with a higher presence of inflammatory immune cells.

CONCLUSIONS

The inflammatory microenvironment can modulate the glycosylation pattern of PDAC cells, increasing the expression of tumor-associated sialylated antigens such as SLe(x), which contributes to pancreatic tumor malignancy.

Development of serum parameters panels for the early detection of pancreatic cancer

Early detection of pancreatic cancer is promising for improving clinical outcome; however, no effective biomarker has yet been identified. Here, we detected 61 clinical serum parameters in 200 healthy controls (Ctrls), 163 pancreatic ductal adenocarcinoma (PDAC) patients and 109 benign pancreatitis patients (Benign) in the training group. A metropolis algorithm with Monte Carlo simulation was used for identifying parameter panels. Sera from 183 Ctrl, 129 PDAC and 95 Benign individuals were used for cross-validation. Samples from 77 breast, 72 cervical, 101 colorectal, 138 gastric, 108 prostate and 132 lung cancer patients were collected for evaluating cancer selectivity. A panel consisting of carbohydrate antigen (CA)19-9, albumin (ALB), C-reactive protein (CRP) and interleukin (IL)-8 had the highest diagnostic value for discriminating between PDAC and Ctrl. The sensitivity (SN) was 99.39% for all-stage, 96.10% for early-stage and 98.80% for advanced-stage PDAC at 90% specificity (SP). In the validation group, the sensitivities were 93.80, 93.10 and 94.40%, respectively, at 90% SP. This panel also identified 80.52% of the breast cancer, 66.67% cervical cancer, 86.14% colorectal cancer, 89.86% gastric cancer, 71.30% prostate cancer and 93.85% lung cancer samples as non-PDAC. The panel consisting of CA19-9, carbon dioxide, CRP and IL-6 panel had the highest diagnostic value for discriminating between PDAC and Benign. The SN was 74.23% for all-stage, 75.30% for early-stage and 74.40% for advanced-stage PDAC at 90% SP. In the validation group, the sensitivities were 72.10, 76.10 and 67.20%, respectively, at 90% SP. Our parameter panels may aid in the early detection of PDAC to improve clinical outcome.

Inflammatory cytokines in human pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal types of cancer with poor prognosis. Despite extensive efforts, the current treatment methods have limited success. Therefore, novel therapeutic approaches are required. The pancreatic tumor microenvironment is rich in growth factors and inflammatory cytokines that support tumor growth, and it is highly immunosuppressive. Up-regulation of cytokine pathways has been shown to modulate PDAC progression and immune evasion; therefore targeting cytokines may have therapeutic benefits. In this review we provide an overview of current understanding of pro- and anti-inflammatory cytokines in pancreatic cancer and their potential as therapeutic targets.

The immune network in pancreatic cancer development and progression

The presence of stromal desmoplasia is a hallmark of spontaneous pancreatic ductal adenocarcinoma, forming a unique microenvironment that comprises many cell types. Only recently, the immune system has entered the pathophysiology of pancreatic ductal adenocarcinoma development. Tumor cells in the pancreas seem to dysbalance the immune system, thus facilitating spontaneous cancer development. This review will try to assemble all relevant data to demonstrate the implications of the immune network on spontaneous cancer development.

Enhancement of specific cellular immune response induced by DNA vaccines encoding PML-RARalpha and hIL-2 genes

A DNA vaccine encoding PML-RAR alpha fusion gene is thought to be a promising approach for acute promyelocytic leukemia patients to enhance immune responses after attaining complete remission. In this study, we sought to enhance cellular immunity by coexpressing human interleukin (hIL)-2 genes. Successfully constructed plasmids PML-RAR alpha-hIL-2-pIRES, PML-RAR alpha-pIRES and hIL-2-pIRES were delivered intramuscularly in BALB/C mice at 14-day intervals for three cycles. The cellular immune responses with respect to the specific cytotoxicity of spleen cells; interferon-gamma secretion in sera, and the T-cell receptor rearrangement excision circles of thymocyte were significantly increased from PML-RARalpha-hIL-2-pIRES immunized mice. Our results indicate that a DNA vaccine with PML fusion gene segment and hIL-2 together might elicit increased cellular immune responses in mice.

PKCalpha-induced drug resistance in pancreatic cancer cells is associated with transforming growth factor-beta1

Background

Drug resistance remains a great challenge in the treatment of pancreatic cancer. The goal of this study was to determine whether TGF-β1 is associated with drug resistance in pancreatic cancer.

Methods

Pancreatic cancer BxPC3 cells were stably transfected with TGF-β1 cDNA. Cellular morphology and cell cycle were determined and the suppressive subtracted hybridization (SSH) assay was performed to identify differentially expressed genes induced by TGF-β1. Western blotting and immunohistochemistry were used to detect expression of TGF-β1-related genes in the cells and tissue samples. After that, the cells were further treated with an anti-cancer drug (e.g., cisplatin) after pre-incubated with the recombinant TGF-β1 plus PKCα inhibitor Gö6976. TGF-β1 type II receptor, TβRII was also knocked down using TβRII siRNA to assess the effects of these drugs in the cells. Cell viability was assessed by MTT assay.

Results

Overexpression of TGF-β1 leads to a markedly increased invasion potential but a reduced growth rate in BxPC3 cells. Recombinant TGF-β1 protein increases expression of PKCα in BxPC3 cells, a result that we confirmed by SSH. Moreover, TGF-β1 reduced the sensitivity of BxPC3 cells to cisplatin treatment, and this was mediated by upregulation of PKCα. However, blockage of PKCα with Gö6976 and TβRII with siRNA reversed the resistance of BxPC3 cells to gemcitabine, even in the presence of TGF-β1. Immunohistochemical data show that pancreatic cancers overexpress TGF-β1 and P-gp relative to normal tissues. In addition, TGF-β1 expression is associated with P-gp and membranous PKCα expression in pancreatic cancer.

Conclusions

TGF-β1-induced drug resistance in pancreatic cancer cells was associated with PKCα expression. The PKCα inhibitor Gö6976 could be a promising agent to sensitize pancreatic cancer cells to chemotherapy.

MeCP2/H3meK9 are involved in IL-6 gene silencing in pancreatic adenocarcinoma cell lines

The aim of the present study was to analyse the molecular mechanisms involved in the Interleukin-6 (IL-6) silencing in pancreatic adenocarcinoma cell lines. Our results demonstrate that TNF-alpha, a major IL-6 inducer, is able to induce IL-6 only in three out of six cell lines examined. 5-aza-2'-deoxycytidine (DAC), but not trichostatin A (TSA), activates the expression of IL-6 in all cell lines, indicating that DNA methylation, but not histone deacetylation, plays an essential role in IL-6 silencing. Indeed, the IL-6 upstream region shows a methylation status that correlates with IL-6 expression and binds MeCP2 and H3meK9 only in the non-expressing cell lines. Our results suggest that critical methylations located from positions -666 to -426 relative to the transcription start site of IL-6 may act as binding sites for MeCP2.

Characterization of tumor-derived pancreatic stellate cells

BACKGROUND

Pancreatic stellate cells (PSCs) are key mediators of the desmoplastic reaction that characterizes pancreatic adenocarcinoma. We sought to isolate and characterize tumor-derived pancreatic stellate (TDPS) cells to further understand how these stromal cells influence pancreatic cancer behavior.

METHODS

We established a stable line of non-immortalized PSCs from a patient with pancreatic adenocarcinoma using a modified prolonged outgrowth method. Cell staining for cytokeratin, vimentin, and alpha smooth muscle actin (alphaSMA) was performed. Total RNA was harvested from TDPS and panc-1 cells and gene expression determined by microarray analysis.

RESULTS

TDPS cells contain lipid droplets in the cytoplasm, and later stain positive for both vimentin and alphaSMA, indicative of activated myofibroblasts. Microarray analysis revealed a distinct gene expression profile compared with pancreatic cancer cells, including expression of proteases that facilitate cancer cell invasion and growth factors known to activate pancreatic cancer cells. Additionally, TDPS cells expressed many of the key components of the pancreatic tumor stroma, including collagen, fibronectin, and S100A4, confirming their importance in the tumor microenvironment.

CONCLUSIONS

Characterization of tumor-derived PSCs will facilitate further studies to determine how the tumor microenvironment promotes the aggressive behavior of pancreatic cancer.

Genetic determined downregulation of both type 1 and type 2 cytokine pathways might be protective against pancreatic cancer

Many cytokine polymorphisms have been studied for associations with susceptibility to breast, gastric, liver, lung, prostate, and ovarian cancer without conclusive results. The cytokine network, indeed, is characterized by complex interactions, and the final biological effect of a single genetic variation depends on the balance among different molecular signals. As is well known, Th1/Th2 cytokine unbalanced production might predispose to different pathologies, cancer included. In general, a prolonged type 1 inflammatory response might allow that cells accumulating enough "genetic hits" are promoted to neoplastic transformation. On the other hand, IL-13-producing cells through the IL-13/IL-4 receptor-alpha (R-alpha) pathway might facilitate escape from tumor immunosurveillance. Here are reported data on the evaluation of the influence of some type 2 and type 1 cytokine genetic polymorphisms as risk factors for pancreatic cancer. There was no overall association between pancreatic cancer risk and single cytokine SNPs. On the other hand, in evaluating the influence of combined cytokine genotypes we found that the combined IL-10-1082GA heterozygous and IL-4 Ralpha-1902AA homozygous genotype is underrepresented in the pancreatic cancer subject group. As is well known, the IL-10-1082GA genotype is associated with an intermediate production of this regulatory cytokine, whereas the IL-10-1902AA genotype of the IL-4Ralpha gene is associated with a reduced efficiency in signal transduction when the receptor is engaged by IL-13 or IL-4. These results strongly suggest that a genetic background associated to a mild downregulation of type 1 and type 2 inflammatory signals might be protective against pancreatic cancer.

CXCL14 expression and potential function in pancreatic cancer

CXC chemokines influence angiogenesis, growth, and metastatic potential of pancreatic cancer. Therefore, the expression and potential function of CXCL14, a recently described CXC chemokine, was evaluated. CXCL14 is upregulated in pancreatic cancer tissues compared to chronic pancreatitis and normal pancreas. Immunolocalization revealed a distinct expression of CXCL14 in tubular complexes in chronic pancreatitis and in particular at the invasive front of pancreatic cancer tissues. Stimulation of pancreatic cancer cells with CXCL14 showed no effects on cell viability and on chemosensitivity. However, CXCL14 clearly increased invasiveness of pancreatic cancer cells without affecting MMP-2 and VEGF secretion, whereas CXCL14 influenced NFkB p65 levels. In conclusion, CXCL14 might play a pivotal role in the pathobiology of pancreatic cancer, probably by regulating cancer invasion.