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

The Natural Product Secoemestrin C Inhibits Colorectal Cancer Stem Cells via p38-S100A8 Feed-Forward Regulatory Loop

Cancer stem cells (CSCs) are closely associated with tumor initiation, metastasis, chemoresistance, and recurrence, which represent some of the primary obstacles to cancer treatment. Targeting CSCs has become an important therapeutic approach to cancer care. Secoemestrin C (Sec C) is a natural compound with strong anti-tumor activity and low toxicity. Here, we report that Sec C effectively inhibited colorectal CSCs and non-CSCs concurrently, mainly by inhibiting proliferation, self-renewal, metastasis, and drug resistance. Mechanistically, RNA-seq analysis showed that the pro-inflammation pathway of the IL17 axis was enriched, and its effector S100A8 was dramatically decreased in Sec C-treated cells, whose roles in the stemness of CSCs have not been fully clarified. We found that the overexpression of S100A8 hindered the anti-CSCs effect of Sec C, and S100A8 deficiency attenuated the stemness traits of CSCs to enhance the Sec C killing activity on them. Meanwhile, the p38 signal pathway, belonging to the IL17 downstream axis, can also mediate CSCs and counter with Sec C. Notably, we found that S100A8 upregulation increased the p38 protein level, and p38, in turn, promoted S100A8 expression. This indicated that p38 may have a mutual feedback loop with S100A8. Our study discovered that Sec C was a powerful anti-colorectal CSC agent, and that the positive feedback loop of p38-S100A8 mediated Sec C activity. This showed that Sec C could act as a promising clinical candidate in colorectal cancer treatment, and S100A8 could be a prospective drug target.

Eliminating the invading extracellular and intracellular FnBp+ bacteria from respiratory epithelial cells by autophagy mediated through FnBp-Fn-Integrin α5β1 axis

Background

We previously found that the respiratory epithelial cells could eliminate the invaded group A streptococcus (GAS) through autophagy induced by binding a fibronectin (Fn) binding protein (FnBp) expressed on the surface of GAS to plasma protein Fn and its receptor integrin α5β1 of epithelial cells. Is autophagy initiated by FnBp+ bacteria via FnBp-Fn-Integrin α5β1 axis a common event in respiratory epithelial cells?

Methods

We chose Staphylococcus aureus (S. aureus/S. a) and Listeria monocytogenes (L. monocytogenes/L. m) as representatives of extracellular and intracellular FnBp+ bacteria, respectively. The FnBp of them was purified and the protein function was confirmed by western blot, viable bacteria count, confocal and pull-down. The key molecule downstream of the action axis was detected by IP, mass spectrometry and bio-informatics analysis.

Results

We found that different FnBp from both S. aureus and L. monocytogenes could initiate autophagy through FnBp-Fn-integrin α5β1 axis and this could be considered a universal event, by which host tries to remove invading bacteria from epithelial cells. Importantly, we firstly reported that S100A8, as a key molecule downstream of integrin β1 chain, is highly expressed upon activation of integrin α5β1, which in turn up-regulates autophagy.

Conclusions

Various FnBp from FnBp+ bacteria have the ability to initiate autophagy via FnBp-Fn-Integrin α5β1 axis to promote the removal of invading bacteria from epithelial cells in the presence of fewer invaders. S100A8 is a key molecule downstream of Integrin α5β1 in this autophagy pathway.

S100a9 inhibits Atg9a transcription and participates in suppression of autophagy in cardiomyocytes induced by β1-adrenoceptor autoantibodies

BACKGROUND

Cardiomyocyte death induced by autophagy inhibition is an important cause of cardiac dysfunction. In-depth exploration of its mechanism may help to improve cardiac dysfunction. In our previous study, we found that β1-adrenergic receptor autoantibodies (β1-AAs) induced a decrease in myocardial autophagy and caused cardiomyocyte death, thus resulting in cardiac dysfunction. Through tandem mass tag (TMT)-based quantitative proteomics, autophagy-related S100a9 protein was found to be significantly upregulated in the myocardial tissue of actively immunized mice. However, whether S100a9 affects the cardiac function in the presence of β1-AAs through autophagy and the specific mechanism are currently unclear.

METHODS

In this study, the active immunity method was used to establish a β1-AA-induced mouse cardiac dysfunction model, and RT-PCR and western blot were used to detect changes in gene and protein expression in cardiomyocytes. We used siRNA to knockdown S100a9 in cardiomyocytes. An autophagy PCR array was performed to screen differentially expressed autophagy-related genes in cells transfected with S100a9 siRNA and negative control siRNA. Cytoplasmic nuclear separation, co-immunoprecipitation (Co-IP), and immunofluorescence were used to detect the binding of S100a9 and hypoxia inducible factor-1α (HIF-1α). Finally, AAV9-S100a9-RNAi was injected into mice via the tail vein to knockdown S100a9 in cardiomyocytes. Cardiac function was detected via ultrasonography.

RESULTS

The results showed that β1-AAs induced S100a9 expression. The PCR array indicated that Atg9a changed significantly in S100a9siRNA cells and that β1-AAs increased the binding of S100a9 and HIF-1α in cytoplasm. Knockdown of S100a9 significantly improved autophagy levels and cardiac dysfunction.

CONCLUSION

Our research showed that β1-AAs increased S100a9 expression in cardiomyocytes and that S100a9 interacted with HIF-1α, which prevented HIF-1α from entering the nucleus normally, thus inhibiting the transcription of Atg9a. This resulted in autophagy inhibition and cardiac dysfunction.

The functions and regulatory pathways of S100A8/A9 and its receptors in cancers

Inflammation primarily influences the initiation, progression, and deterioration of many human diseases, and immune cells are the principal forces that modulate the balance of inflammation by generating cytokines and chemokines to maintain physiological homeostasis or accelerate disease development. S100A8/A9, a heterodimer protein mainly generated by neutrophils, triggers many signal transduction pathways to mediate microtubule constitution and pathogen defense, as well as intricate procedures of cancer growth, metastasis, drug resistance, and prognosis. Its paired receptors, such as receptor for advanced glycation ends (RAGEs) and toll-like receptor 4 (TLR4), also have roles and effects within tumor cells, mainly involved with mitogen-activated protein kinases (MAPKs), NF-κB, phosphoinositide 3-kinase (PI3K)/Akt, mammalian target of rapamycin (mTOR) and protein kinase C (PKC) activation. In the clinical setting, S100A8/A9 and its receptors can be used complementarily as efficient biomarkers for cancer diagnosis and treatment. This review comprehensively summarizes the biological functions of S100A8/A9 and its various receptors in tumor cells, in order to provide new insights and strategies targeting S100A8/A9 to promote novel diagnostic and therapeutic methods in cancers.

Resistance to Gemcitabine in Pancreatic Ductal Adenocarcinoma: A Physiopathologic and Pharmacologic Review

Pancreatic ductal adenocarcinoma (PDAC) is a very aggressive tumor with a poor prognosis and inadequate response to treatment. Many factors contribute to this therapeutic failure: lack of symptoms until the tumor reaches an advanced stage, leading to late diagnosis; early lymphatic and hematic spread; advanced age of patients; important development of a pro-tumoral and hyperfibrotic stroma; high genetic and metabolic heterogeneity; poor vascular supply; a highly acidic matrix; extreme hypoxia; and early development of resistance to the available therapeutic options. In most cases, the disease is silent for a long time, andwhen it does become symptomatic, it is too late for ablative surgery; this is one of the major reasons explaining the short survival associated with the disease. Even when surgery is possible, relapsesare frequent, andthe causes of this devastating picture are the low efficacy ofand early resistance to all known chemotherapeutic treatments. Thus, it is imperative to analyze the roots of this resistance in order to improve the benefits of therapy. PDAC chemoresistance is the final product of different, but to some extent, interconnected factors. Surgery, being the most adequate treatment for pancreatic cancer and the only one that in a few selected cases can achieve longer survival, is only possible in less than 20% of patients. Thus, the treatment burden relies on chemotherapy in mostcases. While the FOLFIRINOX scheme has a slightly longer overall survival, it also produces many more adverse eventsso that gemcitabine is still considered the first choice for treatment, especially in combination with other compounds/agents. This review discusses the multiple causes of gemcitabine resistance in PDAC.

TNFSF9 promotes metastasis of pancreatic cancer by regulating M2 polarization of macrophages through Src/FAK/p-Akt/IL-1β signaling

The effect of tumor necrosis factor superfamily member 9 (TNFSF9) on the metastasis of pancreatic cancer (PC) and the underlying mechanism remain unclear. We studied the expression of TNFSF9 in pancreatic cancer and its relationship with immune cells. We further explored the effect of TNFSF9 on pancreatic cancer metastasis by inducing macrophage polarization, and evaluated the expression of Src/FAK/p-Akt/IL-1β signals in macrophages after knocking down TNFSF9. The data shows that TNFSF9 expression is elevated in pancreatic cancer and is related to the poor prognosis of patients with pancreatic cancer. In addition, TNFSF9 may induce the M2 polarization of macrophages through Src/FAK/p-Akt/IL-1β signals, thereby promoting the migration of pancreatic cancer cells. In conclusion, our data reveals that TNFSF9 may become a predictive biomarker of pancreatic cancer and provides a new intervention target for the immunotherapy of pancreatic cancer.

Identification of differentially expressed proteins involved in fetal scarless wound healing using a rat model of cleft lip

In early pregnancy, fetal skin wounds can heal quickly and undergo a transition period from scarless healing to scar formation. The aim of the present study was to identify potential biomarkers associated with scarless repair of cleft lips, in order to determine the intrinsic factors leading to scar formation in embryonic tissue. A stable model of cleft lip was established using microsurgery by constructing a wedge-shaped cleft lip-like defect in fetal rats at gestational age (GA) 16.5 and GA18.5. The GA16.5 and GA18.5 groups were used to model scarless healing and scar formation, respectively. The fetuses were returned to the uterus following surgery, then removed 72 h after the procedure. Macroscopic observation of the cleft defect and histological examination were carried out. Reverse transcription-quantitative (RT-q) PCR and parallel reaction monitoring (PRM) were used to detect mRNA and protein expression levels, respectively. The upper-left lip completely healed 72 h after surgery in the GA16.5 group of fetal rats. However, this was not the case in the GA18.5 group. Histological examination indicated new follicles visible under the epidermis of the scarless group (GA16.5). Scarring was visible on the upper-left cleft lip wound of the fetal rats in the GA18.5 group. The expression of some growth and pro-inflammatory factors, including TNF-α, were also different between two groups. Label-free quantification was used to identified differentially expressed proteins and five differentially expressed proteins (Smad4, Fabp5, S100a4, S100a8 and S100a9) were identified. The relative expression of these molecules at the mRNA and protein levels were measured using RT-qPCR and PRM. These molecules may represent potential biomarkers for the scarless repair of fetal rat cleft lip wounds.

Extracellular Vesicles and Pancreatic Cancer: Insights on the Roles of miRNA, lncRNA, and Protein Cargos in Cancer Progression

Pancreatic cancer (PC) is among the most devastating digestive tract cancers worldwide. This cancer is characterized by poor diagnostic detection, lack of therapy, and difficulty in predicting tumorigenesis progression. Although mutations of key oncogenes and oncosuppressor involved in tumor growth and in immunosurveillance escape are known, the underlying mechanisms that orchestrate PC initiation and progression are poorly understood or still under debate. In recent years, the attention of many researchers has been concentrated on the role of extracellular vesicles and of a particular subset of extracellular vesicles, known as exosomes. Literature data report that these nanovesicles are able to deliver their cargos to recipient cells playing key roles in the pathogenesis and progression of many pancreatic precancerous conditions. In this review, we have summarized and discussed principal cargos of extracellular vesicles characterized in PC, such as miRNAs, lncRNAs, and several proteins, to offer a systematic overview of their function in PC progression. The study of extracellular vesicles is allowing to understand that investigation of their secretion and analysis of their content might represent a new and potential diagnostic and prognostic tools for PC.

Identification of EMT signaling cross-talk and gene regulatory networks by single-cell RNA sequencing

The epithelial-to-mesenchymal transition (EMT) plays a critical role during normal development and in cancer progression. EMT is induced by various signaling pathways, including TGF-β, BMP, Wnt-β-catenin, NOTCH, Shh, and receptor tyrosine kinases. In this study, we performed single-cell RNA sequencing on MCF10A cells undergoing EMT by TGF-β1 stimulation. Our comprehensive analysis revealed that cells progress through EMT at different paces. Using pseudotime clustering reconstruction of gene-expression profiles during EMT, we found sequential and parallel activation of EMT signaling pathways. We also observed various transitional cellular states during EMT. We identified regulatory signaling nodes that drive EMT with the expression of important microRNAs and transcription factors. Using a random circuit perturbation methodology, we demonstrate that the NOTCH signaling pathway acts as a key driver of TGF-β-induced EMT. Furthermore, we demonstrate that the gene signatures of pseudotime clusters corresponding to the intermediate hybrid EMT state are associated with poor patient outcome. Overall, this study provides insight into context-specific drivers of cancer progression and highlights the complexities of the EMT process.

Targeting Fibrosis: The Bridge That Connects Pancreatitis and Pancreatic Cancer

Pancreatic fibrosis is caused by the excessive deposits of extracellular matrix (ECM) and collagen fibers during repeated necrosis to repair damaged pancreatic tissue. Pancreatic fibrosis is frequently present in chronic pancreatitis (CP) and pancreatic cancer (PC). Clinically, pancreatic fibrosis is a pathological feature of pancreatitis and pancreatic cancer. However, many new studies have found that pancreatic fibrosis is involved in the transformation from pancreatitis to pancreatic cancer. Thus, the role of fibrosis in the crosstalk between pancreatitis and pancreatic cancer is critical and still elusive; therefore, it deserves more attention. Here, we review the development of pancreatic fibrosis in inflammation and cancer, and we discuss the therapeutic strategies for alleviating pancreatic fibrosis. We further propose that cellular stress response might be a key driver that links fibrosis to cancer initiation and progression. Therefore, targeting stress proteins, such as nuclear protein 1 (NUPR1), could be an interesting strategy for pancreatic fibrosis and PC treatment.

S100A8 transported by SEC23A inhibits metastatic colonization via autocrine activation of autophagy

Metastasis is the main cause of failure of cancer treatment. Metastatic colonization is regarded the most rate-limiting step of metastasis and is subjected to regulation by a plethora of biological factors and processes. On one hand, regulation of metastatic colonization by autophagy appears to be stage- and context-dependent, whereas mechanistic characterization remains elusive. On the other hand, interactions between the tumor cells and their microenvironment in metastasis have long been appreciated, whether the secretome of tumor cells can effectively reshape the tumor microenvironment has not been elucidated mechanistically. In the present study, we have identified “SEC23A-S1008-BECLIN1-autophagy axis” in the autophagic regulation of metastatic colonization step, a mechanism that tumor cells can exploit autophagy to exert self-restrain for clonogenic proliferation before the favorable tumor microenvironment is established. Specifically, we employed a paired lung-derived oligometastatic cell line (OL) and the homologous polymetastatic cell line (POL) from human melanoma cell line M14 that differ in colonization efficiency. We show that S100A8 transported by SEC23A inhibits metastatic colonization via autocrine activation of autophagy. Furthermore, we verified the clinical relevance of our experimental findings by bioinformatics analysis of the expression of Sec23a and S100A8 and the clinical-pathological associations. We demonstrate that higher Sec23a and Atg5 expression levels appear to be protective factors and favorable diagnostic (TNM staging) and prognostic (overall survival) markers for skin cutaneous melanoma (SKCM) and colon adenocarcinoma (COAD) patients. And we confirm the bioinformatics analysis results with SKCM biopsy samples.

Local and systemic immunosuppression in pancreatic cancer: Targeting the stalwarts in tumor's arsenal

Late detection, compromised immune system, and chemotherapy resistance underlie the poor patient prognosis for pancreatic ductal adenocarcinoma (PDAC) patients, making it the 3^rd leading cause of cancer-related deaths in the United States. Cooperation between the tumor cells and the immune system leads to the immune escape and eventual establishment of the tumor. For more than 20 years, sincere efforts have been made to intercept the tumor-immune crosstalk and identify the probable therapeutic targets for breaking self-tolerance toward tumor antigens. However, the success of these studies depends on detailed examination and understanding of tumor-immune cell interactions, not only in the primary tumor but also at distant systemic niches. Innate and adaptive arms of the immune system sculpt tumor immunogenicity, where they not only aid in providing an amenable environment for their survival but also act as a driver for tumor relapse at primary or distant organ sites. This review article highlights the key events associated with tumor-immune communication and associated immunosuppression at both local and systemic microenvironments in PDAC. Furthermore, we discuss the approaches and benefits of targeting both local and systemic immunosuppression for PDAC patients. The present articles integrate data from clinical and genetic mouse model studies to provide a widespread consensus on the role of local and systemic immunosuppression in undermining the anti-tumor immune responses against PDAC.

Electron Microscopy-Based Comparison and Investigation of the Morphology of Exosomes Derived from Hepatocellular Carcinoma Cells Isolated at Different Centrifugal Speeds

Exosomes derived from hepatocellular carcinoma (HCC) cells are nanovesicles and are involved in the occurrence and development of HCC, they also serve as important carriers and drug targets of nanodrug delivery systems. The external shape and internal structure of exosomes are important indexes of identification, and isolated intact morphology is crucial to biological function integrity. However, given their susceptibility to various influencing factors, the external shape and internal structure of exosomes derived from HCC cells remain incompletely studied. In this study, exosomes purified from HCC cells were isolated at different centrifugation speeds and examined via multiple electron microscopy (EM) techniques. The results demonstrate that exosomes possess a nearly spherical shape and bilipid membranous vesicle with a concave cavity structure containing electron-dense and coated vesicles, suggesting the possible existence of subpopulations of exosomes with specific functions. The exosomes isolated at ultracentrifugation (UC) speed (≥110,000×g) presented irregular and diverse external morphologies, indicating the effect on the integrity of the exosomes. Transforming growth factor signaling bioactive substances (TGF-β1, S100A8, and S100A9) can be found in exosomes by performing Western blotting, showing that the internal content is associated with metastasis of HCC. These findings show that EMelectron microscopy and UC speed can affect exosome characteristics, including external shape, internal structure, and content of bioactive substances. The electron-dense and coated vesicles that had been discovered in exosomes might become new additional morphological features, which could help to improve the interpretation of experimental results and widen our understanding of exosome morphology.

Immune-Complexome Analysis Identifies Immunoglobulin-Bound Biomarkers That Predict the Response to Chemotherapy of Pancreatic Cancer Patients

Pancreatic Ductal Adenocarcinoma (PDA) is an aggressive malignancy with a very poor outcome. Although chemotherapy (CT) treatment has poor efficacy, it can enhance tumor immunogenicity. Tumor-Associated Antigens (TAA) are self-proteins that are overexpressed in tumors that may induce antibody production and can be PDA theranostic targets. However, the prognostic value of TAA-antibody association as Circulating Immune Complexes (CIC) has not yet been elucidated, mainly due to the lack of techniques that lead to their identification. In this study, we show a novel method to separate IgG, IgM, and IgA CIC from sera to use them as prognostic biomarkers of CT response. The PDA Immune-Complexome (IC) was identified using a LTQ-Orbitrap mass spectrometer followed by computational analysis. The analysis of the IC of 37 PDA patients before and after CT revealed differential associated antigens (DAA) for each immunoglobulin class. Our method identified different PDA-specific CIC in patients that were associated with poor prognosis patients. Finally, CIC levels were significantly modified by CT suggesting that they can be used as effective prognostic biomarkers to follow CT response in PDA patients.

Comparative proteomes change and possible role in different pathways of microRNA-21a-5p in a mouse model of spinal cord injury

Our previous study found that microRNA-21a-5p (miR-21a-5p) knockdown could improve the recovery of motor function after spinal cord injury in a mouse model, but the precise molecular mechanism remains poorly understood. In this study, a modified Allen's weight drop was used to establish a mouse model of spinal cord injury. A proteomics approach was used to understand the role of differential protein expression with miR-21a-5p knockdown, using a mouse model of spinal cord injury without gene knockout as a negative control group. We found that after introducing miR-21a-5p knockdown, proteins that played an essential role in the regulation of inflammatory processes, cell protection against oxidative stress, cell redox homeostasis, and cell maintenance were upregulated compared with the negative control group. Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis identified enriched pathways in both groups, such as the oxidative phosphorylation pathway, which is relevant to Parkinson's disease, Huntington's disease, Alzheimer's disease, and cardiac muscle contraction. We also found that miR-21a-5p could be a potential biomarker for amyotrophic lateral sclerosis, as miR-21a-5p becomes deregulated in this pathway. These results indicate successful detection of some important proteins that play potential roles in spinal cord injury. Elucidating the relationship between these proteins and the recovery of spinal cord injury will provide a reference for future research of spinal cord injury biomarkers. All experimental procedures and protocols were approved by the Experimental Animal Ethics Committee of Shandong University of China on March 5, 2014.

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.

Improving IBD diagnosis and monitoring by understanding preanalytical, analytical and biological fecal calprotectin variability

Background:

The appropriate clinical use of fecal calprotectin (fCal) might be compromised by incomplete harmonization between assays and within- and between-subjects variability. Our aim was to investigate the analytical and biological variability of fCal in order to provide tools for interpreting fCal in the clinical setting.

Methods:

Experiments were conducted to investigate the effects of temperature and storage time on fCal. Thirty-nine controls were enrolled to verify biological variability, and a case-control study was conducted on 134 controls and 110 IBD patients to compare the clinical effectiveness of three different fCal assays: ELISA, CLIA and turbidimetry.

Results:

A 12% decline in fCal levels was observed within 24 h following stool collection irrespective of storage temperature. Samples were unstable following a longer storage time interval at room temperature. Within- and between-subjects fCal biological variability, at 31% and 72% respectively, resulted in a reference change value (RCV) in the region of 100%. fCal sensitivity in distinguishing between controls and IBD patients is satisfactory (68%), and the specificity high (93%) among young (<65 years), but not among older (≥65 years) subjects (ROC area: 0.584; 95% CI: 0.399–0.769). Among the young, assays have different optimal thresholds (120 μg/g for ELISA, 50 μg/g for CLIA and 100 μg/g for turbidimetry).

Conclusions:

We recommend a standardized preanalytical protocol for fCal, avoiding storage at room temperature for more than 24 h. Different cutoffs are recommended for different fCal assays. In monitoring, the difference between two consecutive measurements appears clinically significant when higher than 100%, the fCal biological variability-derived RCV.

Serum amyloid A1 in combination with integrin αVβ3 increases glioblastoma cells mobility and progression

Glioblastoma multiforme (GBM) is a highly malignant type of brain tumor found in humans. GBM cells reproduce quickly, and the median survival time for patients after therapy is approximately 1 year with a high relapse rate. Current therapies and diagnostic tools for GBM are limited; therefore, we searched for a more favorable therapeutic target or marker protein for both therapy and diagnosis. We used mass spectrometry (MS) analysis to identify GBM-associated marker proteins from human plasma and GBM cell cultures. Additional plasma and 52 brain tissues obtained from patients with gliomas were used to validate the association rate of serum amyloid A1 (SAA1) in different grades of gliomas and its distribution in tumors. Microarray database analysis further validated the coefficient of SAA1 levels in gliomas. The cellular mechanisms of SAA1 in GBM proliferation and infiltration were investigated in vitro. We analyzed the correlation between SAA1 and patients' medication requirement to demonstrate the clinical effects of SAA1 in GBM. SAA1 was identified from MS analysis, and its level was revealed to be correlated with the disease grade, clinical severity, and survival rate of patients with gliomas. In vitro cultures, including GBM cells and normal astrocytes, revealed that SAA1 promotes cell migration and invasion through integrin αVβ3 to activate the Erk signaling pathway. Magnetic resonance imaging and tumor region-specific microarray analysis identified a correlation between SAA1 and GBM cell infiltration in patients. In summary, our results demonstrate that SAA1 in combination with integrin αV and β3 can serve as an indicator of high glioblastoma risk. We also identified the cellular mechanisms of SAA1 contributing to GBM progression, which can serve as the basis for future GBM therapy.

Inhibition of Expression of the S100A8 Gene Encoding the S100 Calcium-Binding Protein A8 Promotes Apoptosis by Suppressing the Phosphorylation of Protein Kinase B (Akt) in Endometrial Carcinoma and HEC-1A Cells

Background

The aim of this study was to investigate the expression and silencing of the S100A8 gene, which encodes the S100 calcium-binding protein A8 (S100A8), and apoptosis and phosphorylation of protein kinase B (Akt) in tissue samples of endometrial carcinoma and HEC-1A endometrial adenocarcinoma cells in vitro.

Material/Methods

Immunohistochemistry (IHC) was used to detect expression of the S100A8 protein in 74 tissue samples of endometrial cancer and 22 normal endometrial tissue samples. A stable S100A8 gene knockdown cell line was constructed using lentiviral packing short hairpin RNA (shRNA) transfected into HEC-1A cells. S100A8 mRNA and S100A8 protein levels were detected by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and Western blotting. The effects of expression of the S100A8 gene by endometrial cancer cells was investigated by the MTT assay, cell cycle and apoptotic assays, qRT-PCR, and Western blotting.

Results

IHC showed high levels of expression of S100A8 protein in endometrial carcinoma tissues, and HEC-1A adenocarcinoma cells (in G1 and G2). Increased expression of S100A8 protein was found endometrial cancer tissues compared with normal endometrial tissues (79.7% vs. 4.5%). S100A8 gene knockdown reduced cell proliferation in the HEC-1A cells compared with control cells, induced cell apoptosis, inhibited the phosphorylation of protein kinase B (Akt), and induced the expression of pro-apoptotic genes, including the cytochrome C gene, CYCS, BAD, BAX, FOXO1, FOXO3, CASP9, and CASP3.

Conclusions

In endometrial carcinoma cells, down-regulation of the S100A8 gene induced cell apoptosis via inhibition of the phosphorylated or active form of protein kinase B (Akt).

Methylation of S100A8 is a promising diagnosis and prognostic marker in hepatocellular carcinoma

The abnormality of DNA methylation is one of the major epigenetic alterations in the human hepatocellular carcinoma (HCC). We have assessed the global genomic DNA methylation profiles in human HCC patients by using the Infinium Human Methylation27 BeadChip. A CpG loci of S100A8 was found to be significantly hypomethylated in HCC.

Pooled meta-analysis of five validation public datasets demonstrated its methylation level was significantly lower for HCC compared to paired adjacent normal tissues. Quantitative pyrosequencing analysis also showed that the S100A8 methylation level was decreased in cancer tissues (31.90%±13.31%) than that in the paired adjacent normal tissues (65.33%±3.64%, p<0.01). The area under the ROC curve (AUC) value was 0.950 (p<0.01). Kaplan-Meier survival curves revealed that hypomethylation of S100A8 was associated with shortened overall survival (OS) and progression-free survival (PFS) (log rank p<0.05). Multivariate Cox proportional hazards model also indicated significantly shorter OS (HR, 1.709; 95 % CI, 1.127–2.591) and PFS (HR, 1.767; 95 % CI, 1.168–2.974) were observed in the low-methylation-level group compared to the high-methylation-level group. Furthermore, S100A8 overexpression in Huh7 and MHCC-97H hepatoma cell lines led to increased cell proliferation, migration, invasion, and tumor growth. These findings suggested S100A8 methylation to be served as potential diagnosis and prognosis marker for HCC. S100A8 also may play as a tumor promoter in HCC.

S100A9 gene silencing inhibits the release of pro-inflammatory cytokines by blocking the IL-17 signalling pathway in mice with acute pancreatitis

The study aimed to investigate whether S100A9 gene silencing mediating the IL‐17 pathway affected the release of pro‐inflammatory cytokines in acute pancreatitis (AP). Kunming mice were assigned to the normal, AP, AP + negative control (NC), AP + shRNA, AP + IgG and AP + anti IL‐17 groups. ELISA was applied to measure expressions of AMY, LDH, CRP, TNF‐α, IL‐6 and IL‐8. The cells were distributed into the control, blank, NC, shRNA1 and shRNA2 groups. MTT assay, flow cytometry, RT‐qPCR and Western blotting were used to evaluate cell proliferation, cell cycle and apoptosis, and expressions of S100A9, TLR4, RAGE, IL‐17, HMGB1 and S100A12 in tissues and cells. Compared with the normal group, the AP group displayed increased expressions of AMY, LDH, CRP, TNFα, IL‐6, IL‐8, S100A9, TLR4, RAGE, IL‐17, HMGB1 and S100A12. The AP + shRNA and AP + anti IL‐17 groups exhibited an opposite trend. The in vivo results: Compare with the control group, the blank, NC, shRNA1 and shRNA2 groups demonstrated increased expressions of S100A9, TLR4, RAGE, IL‐17, HMGB1 and S100A12, as well as cell apoptosis and cells at the G1 phase, with reduced proliferation. Compared with the blank and NC groups, the shRNA1 and shRNA2 groups had declined expressions of S100A9, TLR4, RAGE, IL‐17, HMGB1 and S100A12, as well as cell apoptosis and cells at the G1 phase, with elevated proliferation. The results indicated that S100A9 gene silencing suppressed the release of pro‐inflammatory cytokines through blocking of the IL‐17 pathway in AP.

Protein S100-A8: A potential metastasis-associated protein for breast cancer determined via iTRAQ quantitative proteomic and clinicopathological analysis

Breast cancer is the most common malignancy in females, with metastasis of this type of cancer frequently proving lethal. However, there are still no effective biomarkers to predict breast cancer metastasis. The aim of the present study was, therefore, to analyze breast cancer metastasis-associated proteins and evaluate the association between protein S100-A8 and the prognosis of breast cancer. The isobaric tags for relative and absolute quantitation (iTRAQ) proteomic technique was used to analyze the differential expression of proteins between fresh primary breast tumor (PBT) tissue and fresh paired metastatic lymph nodes (PMLN) tissue. Subsequently, immunohistochemical staining was used to locate and assess the expression of protein S100-A8 in benign breast disease (n=15), primary breast cancer with (n=109) or without (n=83) metastasis, and in paired metastatic lymph nodes (n=109) formalin fixed paraffin embedded (FFPE) tissue. Staining scores were evaluated and the association between protein S100-A8 expression levels and the clinicopathological characteristics of 192 patients with breast cancer were evaluated using the χ² test. Kaplan-Meier and Cox hazards regression analyses were utilized to investigate the association between the expression of protein S100-A8 and the prognosis of patients with breast cancer. A total of 4,837 proteins were identified using the iTRAQ proteomic technique. Among these proteins, 643 differentially expressed proteins were revealed. Protein S100-A8 expression levels were identified to differ between PBT and PMLN tissues. Immunohistochemical staining suggested a significant difference between NMBT and PMLN (P=0.002), and also between PBT and PMLN (P<0.001). Cox hazards regression model analyses suggested that histological grade (P=0.031) and nodal status (P=0.001) were risk factors for lymph nodes metastasis of breast cancer. Kaplan-Meier analyses revealed no significant relationship between protein S100-A8 expression level and overall survival rate of patients with breast cancer. In conclusion, by using the iTRAQ proteomic technique and immunohistochemistry staining, it was identified that protein S100-A8 may be associated with lymph nodes metastasis of breast cancer and be a marker for progression of breast cancer.

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.

High expression of S100A8 gene is associated with drug resistance to etoposide and poor prognosis in acute myeloid leukemia through influencing the apoptosis pathway

S100A8 has been increasingly recognized as a biomarker in multiple solid tumors and has played pivotal roles in hematological malignancies. S100A8 is potentially an indicator for poor survival in acute myeloid leukemia (AML) in retrospective studies. However, the mechanisms of S100A8 are diverse in cancers. In this study, we investigated the correlation of S100A8 at the transcription level with clinical parameters in 91 de novo AML patients and explored its mechanisms of chemoresistance to etoposide in vitro. The transcription level of S100A8 was significantly lower at initial and relapse stages of AML samples than at complete remission (P<0.001) and than in the control group (P=0.0078), while no significant difference could be found between initial and relapse stages (P=0.257). Patients with high transcription levels of S100A8 exhibited a shorter overall survival (P=0.0012). HL-60 cells transfected with S100A8 showed resistance to etoposide with a higher level IC50 value and lower apoptosis rate compared with HL-60 cells transfected with empty vector. Thirty-six genes were significantly downregulated and 12 genes were significantly upregulated in S100A8 overexpression group compared with control group in which 360 genes involved in apoptotic genes array were performed by real-time reverse transcriptase polymerase chain reaction. Among them, the caspase-3, Bcl-2, and Bax were verified by Western blot analysis which indicated that the role of S100A8 in resistance to chemotherapy was closely related with antiapoptosis. In conclusion, critical S100A8 provided useful clinical information in predicting the outcome of AML. The main mechanism of S100A8 which promoted chemoresistance was antiapoptosis.

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.

Chronic alcohol exposure exacerbates inflammation and triggers pancreatic acinar-to-ductal metaplasia through PI3K/Akt/IKK

Pancreatic acinar-to-ductal metaplasia (ADM) has been identified as an initiating event that can progress to pancreatic intraepithelial neoplasia (PanIN) or pancreatic ductal adenocarcinoma (PDAC). Acini transdifferentiation can be induced by persistent inflammation. Notably, compelling evidence has emerged that chronic alcohol exposure may trigger an inflammatory response of macrophages/monocytes stimulated by endotoxins. In the present study, we aimed to evaluate the role of inflammation induced by chronic alcohol and lipopolysaccharide (LPS) exposure in the progression of pancreatic ADM, as well as to elucidate the possible mechanisms involved. For this purpose, cultured macrophages were exposed to varying doses of alcohol for 1 week prior to stimulation with LPS. Tumor necrosis factor-α (TNF-α) and regulated upon activation, normal T cell expression and secreted (RANTES) expression were upregulated in the intoxicated macrophages with activated nuclear factor-κB (NF-κB). Following treatment with the supernatant of intoxicated macrophages, ADM of primary acinar cells was induced. Furthermore, the expression of TNF-α and RANTES, as well as the phosphatidylinositol-3-kinase (PI3K)/protein kinase B(Akt)/inhibitory κB kinase (IKK) signaling pathway have been proven to be involved in the ADM of acinar cells. Moreover, Sprague-Dawley (SD) rats were employed to further explore the induction of pancreatic ADM by chronic alcohol and LPS exposure in vivo. At the end of the treatment period, a number of physiological parameters, such as body weight, liver weight and pancreatic weight were reduced in the exposed rats. Plasma alcohol concentrations and oxidative stress levels in the serum, as well as TNF-α and RANTES expression in monocytes were also induced following chronic alcohol and LPS exposure. In addition, pancreatic ADM was induced through the PI3K/Akt/IKK signaling pathway by the augmented TNF-α and RANTES expression levels in the exposed rats. Overall, we characterized the link between inflammation induced by chronic alcohol and LPS exposure and pancreatic ADM. However, the mechanisms behind the induction of pancreatic ADM warrant further investigation.