Emerging role of monocytes and their intracellular calcium pattern in spondyloarthritis

Spondyloarthritis (SpA) comprises multifactorial diseases characterized by a complex interplay between an inherited background and environmental factors that lead to immune response dysregulation and inflammation. Unlike for other rheumatic diseases, no specific biomarkers are available in clinical practice for diagnosing SpA. The aim of the present study was to search new potential biomarkers for SpA diagnosis by focusing on the innate immune response. An evaluation was made of the mRNA expression levels of inflammatory cytokines (TNF-α, IL-1β, TGF-β1, S100A8, S100A9) and matrix metalloproteinases (MMP3, MMP8, MMP9) in blood mononuclear cells of SpA patients (n = 64) with respect to controls (n = 100). In parallel, the pattern of intracellular calcium flows of blood monocytes was verified in order to ascertain whether any specific fingerprint characterizes innate immune cells in SpA patients. Inflammatory cytokines and MMPs expression levels were not correlated with SpA, while in this disease a reduced expression of the S100A8 and a decreased frequency of monocytes showing intracellular calcium flows were observed. In conclusion, no specific signs of systemic inflammation are detectable in SpA, but the disease affects the "on-off" mechanisms that regulate the concentration of intracellular calcium and calcium-related proteins. This potentially pave the way for the discovery of new biomarkers.

Glucose metabolism during tumorigenesis in the genetic mouse model of pancreatic cancer

AIM

More than 40% of pancreatic ductal adenocarcinoma (PDAC) patients have glucose intolerance or diabetes. The association has led to two hypotheses: PDAC causes diabetes or diabetes shares risk factors for the development of PDAC. In order to elucidate the relationship between diabetes and PDAC, we investigated the glucose metabolism during tumorigenesis in the LSL-KrasG12D/+; LSL-Trp53R172H/+; and Pdx-1-Cre (KPC) mouse, a genetically engineered model of PDAC.

METHODS

Male and female KPCs have been fed with standard diet (SD) or high-fat diet (HFD). The imaging-based 4-class tumor staging was used to follow pancreatic cancer development. Not fasting glycemia, 4-h fasting glycemia, insulin, C-peptide, glucose tolerance after OGTT and abdominal fat volume were measured during tumorigenesis.

RESULTS

PDAC development did not lead to an overt diabetic phenotype or to any alterations in glucose tolerance in KPC fed with SD. Consumption of HFD induced higher body weight/abdominal fat volume and worsened glucose homeostasis both in control CRE mice and only in early tumorigenesis stages of the KPC mice, excluding that the cancer development itself acts as a trigger for the onset of dysmetabolic features.

CONCLUSION

Our data demonstrate that carcinogenesis in KPC mice is not associated with paraneoplastic diabetes.

Inflammation and Pancreatic Cancer: Focus on Metabolism, Cytokines, and Immunity

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_reg, 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.

Contribution of biomarkers for pancreatic cancer-associated new-onset diabetes to pancreatic cancer screening

BACKGROUND

Pancreatic cancer (PaC) is one of the deadliest types of tumor, and it is regarded as a fatal disease, with a 5-year survival rate less than 10%. Most clinical diagnoses for PaC are made at an advanced stage because of the insidious onset of the disease, which leads to an extremely poor prognosis.

RECENT FINDINGS

The relationship between diabetes mellitus (DM) and PaC has been established by several decades of research, and the prevalence of DM in patients with PaC has been reported to be 40%, with half of the patients having developed new-onset DM within 2 years or less. Increasing evidence suggests that new-onset DM is associated with a high prevalence of PaC, and PaC resection ameliorates DM. Therefore, screening for PaC may be needed in patients with newly developed DM.

PURPOSE

The objective of this review was to present our current understanding of biomarkers for PaC-associated new-onset DM (PCAND), to offer a perspective on the prospects and problems of using this strategy for early screening to differentiate PCAND from new-onset type 2 DM not associated with PaC and to suggest candidate biomarkers to use for PaC screening in patients with new-onset DM. Finding sensitive and specific biomarkers to manage these patients constitutes a challenge for the research community and for public health policies.

Signaling between pancreatic β cells and macrophages via S100 calcium-binding protein A8 exacerbates β-cell apoptosis and islet inflammation

Chronic low-grade inflammation in the pancreatic islets is observed in individuals with type 2 diabetes, and macrophage levels are elevated in the islets of these individuals. However, the molecular mechanisms underlying the interactions between the pancreatic β cells and macrophages and their involvement in inflammation are not fully understood. Here, we investigated the role of S100 calcium-binding protein A8 (S100A8), a member of the damage-associated molecular pattern molecules (DAMPs), in β-cell inflammation. Co-cultivation of pancreatic islets with unstimulated peritoneal macrophages in the presence of palmitate (to induce lipotoxicity) and high glucose (to induce glucotoxicity) synergistically increased the expression and release of islet-produced S100A8 in a Toll-like receptor 4 (TLR4)-independent manner. Consistently, a significant increase in the expression of the S100a8 gene was observed in the islets of diabetic db/db mice. Furthermore, the islet-derived S100A8 induced TLR4-mediated inflammatory cytokine production by migrating macrophages. When human islet cells were co-cultured with U937 human monocyte cells, the palmitate treatment up-regulated S100A8 expression. This S100A8-mediated interaction between islets and macrophages evoked β-cell apoptosis, which was ameliorated by TLR4 inhibition in the macrophages or S100A8 neutralization in the pancreatic islets. Of note, both glucotoxicity and lipotoxicity triggered S100A8 secretion from the pancreatic islets, which in turn promoted macrophage infiltration of the islets. Taken together, a positive feedback loop between islet-derived S100A8 and macrophages drives β-cell apoptosis and pancreatic islet inflammation. We conclude that developing therapeutic approaches to inhibit S100A8 may serve to prevent β-cell loss in patients with diabetes.

The TGF-β/Smad4 Signaling Pathway in Pancreatic Carcinogenesis and Its Clinical Significance

Pancreatic ductal adenocarcinoma (PDAC) is one of the most fatal human cancers due to its complicated genomic instability. PDAC frequently presents at an advanced stage with extensive metastasis, which portends a poor prognosis. The known risk factors associated with PDAC include advanced age, smoking, long-standing chronic pancreatitis, obesity, and diabetes. Its association with genomic and somatic mutations is the most important factor for its aggressiveness. The most common gene mutations associated with PDAC include KRas2, p16, TP53, and Smad4. Among these, Smad4 mutation is relatively specific and its inactivation is found in more than 50% of invasive pancreatic adenocarcinomas. Smad4 is a member of the Smad family of signal transducers and acts as a central mediator of transforming growth factor beta (TGF-β) signaling pathways. The TGF-β signaling pathway promotes many physiological processes, including cell growth, differentiation, proliferation, fibrosis, and scar formation. It also plays a major role in the development of tumors through induction of angiogenesis and immune suppression. In this review, we will discuss the molecular mechanism of TGF-β/Smad4 signaling in the pathogenesis of pancreatic adenocarcinoma and its clinical implication, particularly potential as a prognostic factor and a therapeutic target.

SMAD4 loss enables EGF, TGFβ1 and S100A8/A9 induced activation of critical pathways to invasion in human pancreatic adenocarcinoma cells

Epidermal Growth Factor (EGF) receptor overexpression, KRAS, TP53, CDKN2A and SMAD4 mutations characterize pancreatic ductal adenocarcinoma. This mutational landscape might influence cancer cells response to EGF, Transforming Growth Factor β1 (TGFβ1) and stromal inflammatory calcium binding proteins S100A8/A9. We investigated whether chronic exposure to EGF modifies in a SMAD4-dependent manner pancreatic cancer cell signalling, proliferation and invasion in response to EGF, TGFβ1 and S100A8/A9. BxPC3, homozigously deleted (HD) for SMAD4, and BxPC3-SMAD4+ cells were or not stimulated with EGF (100 ng/mL) for three days. EGF pre-treated and non pretreated cells were stimulated with a single dose of EGF (100 ng/mL), TGFβ1 (0,02 ng/mL), S100A8/A9 (10 nM). Signalling pathways (Reverse Phase Protein Array and western blot), cell migration (Matrigel) and cell proliferation (XTT) were evaluated. SMAD4 HD constitutively activated ERK and Wnt/β-catenin, while inhibiting PI3K/AKT pathways. These effects were antagonized by chronic EGF, which increased p-BAD (anti-apoptotic) in response to combined TGFβ1 and S100A8/A9 stimulation. SMAD4 HD underlied the inhibition of NF-κB and PI3K/AKT in response to TGFβ1 and S100A8/A9, which also induced cell migration. Chronic EGF exposure enhanced cell migration of both BxPC3 and BxPC3-SMAD4+, rendering the cells less sensitive to the other inflammatory stimuli. In conclusion, SMAD4 HD is associated with the constitutive activation of the ERK and Wnt/β-catenin signalling pathways, and favors the EGF-induced activation of multiple signalling pathways critical to cancer proliferation and invasion. TGFβ1 and S100A8/A9 mainly inhibit NF-κB and PI3K/AKT pathways and, when combined, sinergize with EGF in enhancing anti-apoptotic p-BAD in a SMAD4-dependent manner.

Intracellular calcium oscillations in strongly metastatic human breast and prostate cancer cells: control by voltage-gated sodium channel activity

The possible association of intracellular Ca²⁺ with metastasis in human cancer cells is poorly understood. We have studied Ca²⁺ signaling in human prostate and breast cancer cell lines of strongly versus weakly metastatic potential in a comparative approach. Intracellular free Ca²⁺ was measured using a membrane-permeant fluorescent Ca²⁺-indicator dye (Fluo-4 AM) and confocal microscopy. Spontaneous Ca²⁺ oscillations were observed in a proportion of strongly metastatic human prostate and breast cancer cells (PC-3M and MDA-MB-231, respectively). In contrast, no such oscillations were observed in weakly/non metastatic LNCaP and MCF-7 cells, although a rise in the resting Ca²⁺ level could be induced by applying a high-K⁺ solution. Various parameters of the oscillations depended on extracellular Ca²⁺ and voltage-gated Na⁺ channel activity. Treatment with either tetrodotoxin (a general blocker of voltage-gated Na⁺ channels) or ranolazine (a blocker of the persistent component of the channel current) suppressed the Ca²⁺ oscillations. It is concluded that the functional voltage-gated Na⁺ channel expression in strongly metastatic cancer cells makes a significant contribution to generation of oscillatory intracellular Ca²⁺ activity. Possible mechanisms and consequences of the Ca²⁺ oscillations are discussed.

Blood expression of matrix metalloproteinases 8 and 9 and of their inducers S100A8 and S100A9 supports diagnosis and prognosis of PDAC-associated diabetes mellitus

BACKGROUND

Based on the knowledge that matrix metalloproteinases (MMPs) and S100A8/A9 synergistically work in causing PDAC-associated type 2 diabetes mellitus (T2DM), we verified whether tissue and blood MMP8, MMP9, S100A8 and S100A9 expression might help in distinguishing PDAC among diabetics.

METHODS

Relative quantification of MMP8, MMP9, S100A8 and S100A9 mRNA was performed in tissues obtained from 8 PDAC, 4 chronic pancreatitis (ChrPa), 4 non-PDAC tumors and in PBMCs obtained from 30 controls, 43 T2DM, 41 ChrPa, 91 PDAC and 33 pancreatic-biliary tract tumors.

RESULTS

T2DM was observed in PDAC (66%), in pancreatic-biliary tract tumors (64%) and in ChrPa (70%). In diabetics, with or without PDAC, MMP9 tissue expression was increased (p<0.05). Both MMPs increased in PDAC and MMP9 increased also in pancreatic-biliary tract tumors PBMCs. In diabetics, MMP9 was independently associated with PDAC (p=0.025), but failed to enhance CA 19-9 discriminant efficacy. A highly reduced S100A9 expression, found in 7 PDAC, was significantly correlated with a reduced overall survival (p=0.015).

CONCLUSIONS

An increased expression of tissue and blood MMP9 reflects the presence of PDAC-associated diabetes mellitus. This finding fits with the hypothesized role of MMPs as part of the complex network linking cancer to diabetes.

The role of S100 proteins and their receptor RAGE in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with low survival rates. Current therapeutic treatments have very poor response rates due to the high inherent chemoresistance of the pancreatic-cancer cells. Recent studies have suggested that the receptor for advanced glycation end products (RAGE) and its S100 protein ligands play important roles in the progression of PDAC. We will discuss the potential role of S100 proteins and their receptor, RAGE, in the development and progression of pancreatic cancer.

Inflammation and pancreatic cancer: molecular and functional interactions between S100A8, S100A9, NT-S100A8 and TGFβ1

BACKGROUND

In order to gain further insight on the crosstalk between pancreatic cancer (PDAC) and stromal cells, we investigated interactions occurring between TGFβ1 and the inflammatory proteins S100A8, S100A9 and NT-S100A8, a PDAC-associated S100A8 derived peptide, in cell signaling, intracellular calcium (Cai2+) and epithelial to mesenchymal transition (EMT). NF-κB, Akt and mTOR pathways, Cai2+ and EMT were studied in well (Capan1 and BxPC3) and poorly differentiated (Panc1 and MiaPaCa2) cell lines.

RESULTS

NT-S100A8, one of the low molecular weight N-terminal peptides from S100A8 to be released by PDAC-derived proteases, shared many effects on NF-κB, Akt and mTOR signaling with S100A8, but mainly with TGFβ1. The chief effects of S100A8, S100A9 and NT-S100A8 were to inhibit NF-κB and stimulate mTOR; the molecules inhibited Akt in Smad4-expressing, while stimulated Akt in Smad4 negative cells. By restoring Smad4 expression in BxPC3 and silencing it in MiaPaCa2, S100A8 and NT-S100A8 were shown to inhibit NF-κB and Akt in the presence of an intact TGFβ1 canonical signaling pathway. TGFβ1 counteracted S100A8, S100A9 and NT-S100A8 effects in Smad4 expressing, not in Smad4 negative cells, while it synergized with NT-S100A8 in altering Cai2+ and stimulating PDAC cell growth. The effects of TGFβ1 on both EMT (increased Twist and decreased N-Cadherin expression) and Cai2+ were antagonized by S100A9, which formed heterodimers with TGFβ1 (MALDI-TOF/MS and co-immuno-precipitation).

CONCLUSIONS

The effects of S100A8 and S100A9 on PDAC cell signaling appear to be cell-type and context dependent. NT-S100A8 mimics the effects of TGFβ1 on cell signaling, and the formation of complexes between TGFβ1 with S100A9 appears to be the molecular mechanism underlying the reciprocal antagonism of these molecules on cell signaling, Cai2+ and EMT.

The S100A8/A9 complex reduces CTLA4 expression by immature myeloid cells: Implications for pancreatic cancer-driven immunosuppression

An expansion of different myeloid derived suppressive cell (MDSC) subsets can be detected in the blood and secondary lymphoid organs of early and advanced pancreatic ductal adenocarcinoma (PDAC) patients. Double negative (CD14⁻HLA-DR⁻) MDSCs are frequently induced by PDACs. In addition, by releasing S100A8 and S100A9, advanced PDAC lesions cause an expansion of highly immunosuppressive CD33⁺CD14⁺HLA-DR⁻ monocytic MDSCs expressing low levels of cytotoxic T lymphocyte antigen 4 (CTLA4) on the cell surface.

Usefulness of MALDI-TOF/MS identification of low-MW fragments in sera for the differential diagnosis of pancreatic cancer

OBJECTIVES

To identify new biomarkers of pancreatic cancer (PaCa), we performed MALDI-TOF/MS analysis of sera from 22 controls, 51 PaCa, 37 chronic pancreatitis, 24 type II diabetes mellitus (DM), 29 gastric cancer (GC), and 24 chronic gastritis (CG).

METHODS

Sera were purified by Sep-Pak C18 before MALDI-TOF/MS Anchorchip analysis.

RESULTS

Features present in at least 5% of all spectra were selected (n = 160, m/z range, 1200-5000). At univariate analysis, 2 features (m/z 2049 and 2305) correlated with PaCa, 3 (m/z 1449, 1605, and 2006) with DM. No feature characterized gastric cancer or chronic gastritis. Ten-fold cross-validation binary recursive partitioning trees were obtained for patients' classification. The tree (CA 19-9, age, m/z 2006, 2599, 2753, and 4997), built considering only patients with diabetes, allowed a distinction between DM [area under the receiver operating characteristic curve (AUC), 0.997], chronic pancreatitis (AUC, 0.968), and PaCa (AUC, 0.980), with an overall correct classification rate of 89%. The tree including CA 19-9, 1550, and 2937 m/z features, achieved an AUC of 0.970 in distinguishing localized from advanced PaCa. MALDI-TOF-TOF analysis revealed the 1550 feature as a fragment of Apo-A1, which was determined as whole protein and demonstrated to be closely correlated with PaCa.

CONCLUSIONS

The findings made demonstrate a role for serum peptides identified using MALDI-TOF/MS for addressing PaCa diagnosis.

Pancreatic tumors and immature immunosuppressive myeloid cells in blood and spleen: role of inhibitory co-stimulatory molecules PDL1 and CTLA4. An in vivo and in vitro study

BACKGROUND

Blood and spleen expansion of immature myeloid cells (IMCs) might compromise the immune response to cancer. We studied in vivo circulating and splenic T lymphocyte and IMC subsets in patients with benign and malignant pancreatic diseases. We ascertained in vitro whether pancreatic adenocarcinoma (PDAC)-associated IMC subsets are induced by tumor-derived soluble factors and whether they are immunosuppressive focusing on the inhibitory co-stimulatory molecules PDL1 and CTLA4.

METHODOLOGY AND PRINCIPAL FINDINGS

103 pancreatic and/or splenic surgical patients were enrolled including 52 PDAC, 10 borderline and 10 neuroendocrine tumors (NETs). Lymphocytes and IMCs were analysed by flow cytometry in blood, in spleen and in three PDAC cell conditioned (CM) or non conditioned PBMC. PDL1 and CTLA4 were studied in 30 splenic samples, in control and conditioned PBMC. IMCs were FACS sorted and co-coltured with allogenic T lymphocytes. In PDAC a reduction was found in circulating CD8(+) lymphocytes (p = 0.004) and dendritic cells (p = 0.01), which were reduced in vitro by one PDAC CM (Capan1; p = 0.03). Blood myeloid derived suppressive cells (MDSCs) CD33(+)CD14(-)HLA-DR(-) were increased in PDAC (p = 0.022) and were induced in vitro by BxPC3 CM. Splenic dendritic cells had a higher PDL1 expression (p = 0.007), while CD33(+)CD14(+)HLA-DR(-) IMCs had a lower CTLA4 expression (p = 0.029) in PDAC patients. In vitro S100A8/A9 complex, one of the possible inflammatory mediators of immune suppression in PDAC, induced PDL1 (p = 0.018) and reduced CTLA4 expression (p = 0.028) among IMCs. IMCs not expressing CTLA4 were demonstrated to be immune suppressive.

CONCLUSION

In PDAC circulating dendritic and cytotoxic T cells are reduced, while MDSCs are increased and this might favour tumoral growth and progression. The reduced CTLA4 expression found among splenic IMCs of PDAC patients was demonstrated to characterize an immune suppressive phenotype and to be consequent to the direct exposure of myeloid cells to pancreatic cancer derived products, S100A8/A9 complex in particular.

The bidirectional interation between pancreatic cancer and diabetes

The bidirectional interation between pancreatic cancer (PanCa) and diabetes has been confirmed by epidemiological studies, which provide evidence-based medical support for further research into the mechanisms involved in the interaction. We reviewed the literature regarding the role of diabetes in the generation and progression of PanCa and the mechanism by which PanCa induces diabetes for its malignant progression. The effect of antidiabetic drugs on the occurrence and prognosis of PanCa was also reviewed. Diabetes may directly promote the progression of PanCa by pancreatic duct enlargement and hypertension, as well as by enabling an increased tumor volume. Hyperinsulinemia, insulin resistance, cytokines, hyperglycemia and genotype change are also important factors in the progression of PanCa with diabetes. Hyperglycemia may be the first clinical manifestation and is helpful in the early diagnosis of PanCa. Furthermore, antidiabetic drugs can have different effects on the occurrence and prognosis of PanCa. The bidirectional interation between PanCa and diabetes is involved in the occurrence, proliferation, invasion, metastasis and prognosis of PanCa with diabetes. The discovery of biomarkers for the early diagnosis of PanCa, as well as the novel usage of metformin for its antitumor effects and determining the potential mechanisms of these effects, may be the next direction for PanCa research and treatment.