Calcium-binding proteins S100A8 and S100A9 as novel diagnostic markers in human prostate cancer

Measurement of urinary canine S100A8/A9 and S100A12 concentrations as candidate biomarkers of lower urinary tract neoplasia in dogs

Members of the S100 family of calcium-binding proteins (S100A8, A9, and A12; calgranulins) have been associated with inflammation and cancer in human beings. Proteins S100A8 and A9 were overexpressed in human patients with transitional cell carcinoma (TCC) and prostate carcinoma (PCA), suggesting their potential as biomarkers for diagnosing and/or predicting the progression of such neoplasms. Calgranulins have not been studied in dogs with TCC or PCA. Established in-house immunoassays were validated and found suitable for measuring S100A8/A9 and S100A12 in canine urine samples to allow the study of the role of these biomarkers in dogs with TCC or PCA. Urinary calgranulin concentrations were not affected by blood contamination (e.g., due to cystocentesis), and should be normalized against urine specific gravity or urinary creatinine concentration. Urinary calgranulin concentrations were significantly increased in 11 dogs with TCC or PCA (untreated) compared to 42 healthy dogs, and the ratio between S100A8/A9 and S100A12 was significantly higher in 11 dogs with TCC or PCA than in 10 dogs diagnosed with a urinary tract infection, suggesting that calgranulins are potential biomarkers for TCC or PCA in canine patients. The clinical utility of measuring urinary calgranulins in dogs with suspected TCC or PCA warrants further investigation.

Mechanisms of action of tasquinimod on the tumour microenvironment

Tasquinimod is a small molecule with pleiotropic effects on the tumour microenvironment. Tasquinimod inhibits the growth and metastasis of tumour cells in vitro and in vivo. It targets the tumour microenvironment, enhancing the host immune response and inhibiting the angiogenic response. Tasquinimod influences infiltrating myeloid cells in the tumour milieu shifting the balance towards a less immunosuppressive phenotype. Myeloid-derived suppressor cells and tumour-associated macrophages are major components of the immunosuppressive microenvironment and as a result promote tumour growth and favour angiogenesis and metastasis formation. Growing evidence indicates that tasquinimod targets these myeloid cells and modulates local tumour immunity by blocking the interaction between the multifunctional protein S100A9 and its ligands receptor of advanced glycation end products and Toll-like receptor 4. Its anti-angiogenic effects are achieved at least in part through these effects on regulatory myeloid cells and also potentially through inactivating histone deacetylase-4 and reducing expression of hypoxia-inducible factor 1-controlled genes. The aim is to comprehensively review the mode of action of tasquinimod as a novel oral anti-cancer agent. Based on its unique combination of effects, tasquinimod is a novel agent with clinical therapeutic potential in various solid tumours, both alone and as part of rational combination therapy.

A prospective proteomic-based study for identifying potential biomarkers for the diagnosis of cholangiocarcinoma

BACKGROUND

Cholangiocarcinoma (CCA) is becoming a common fatal hepatic tumor. Early detection of CCA is hampered by the absence of a sufficiently accurate and noninvasive diagnostic test. Proteomic analysis would be a powerful tool to identify potential biomarkers of this cancer.

AIMS

This study aims to identify new protein markers that are specific for CCA using proteomic approaches and to evaluate the performance of S100 calcium-binding protein A9 (S100A9) and chaperonin-containing TCR1, subunit 3 (CCTγ) as diagnostic markers for screening test of CCA.

METHODS

Two-dimensional differential gel electrophoresis (2-D DIGE) coupled with matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry were used to analyze and screen biomarker candidates in the proteomes of five human CCA samples and five healthy control samples. Subsequently, two potential biomarkers, S100A9 and CCTγ, were chosen for validation and analysis by immunohistochemical methods using CCA tissue microarrays.

RESULTS

Twenty protein spots were significantly elevated and five protein spots were downregulated in all patients (p < 0.05). The positive rate was significantly higher in patients with CCA (48 ± 35%) compared with the normal liver control group (5 ± 10%, p < 0.001), the hepatocellular carcinoma group (15 ± 20%, p < 0.001), and the cirrhosis group (12 ± 16%, p < 0.001). A greater proportion of patients with CCA were positive for CCTγ (72 ± 18%) compared with the normal liver control group (43 ± 22%, p < 0.001), the hepatocellular carcinoma group (45 ± 20%, p < 0.001), and the cirrhosis group (39 ± 25%, p < 0.001).

CONCLUSIONS

Combined comparative proteomic analysis using 2-D DIGE and MALDI-TOF is an effective method for identifying differentially expressed proteins in CCA tissues. The expression of S100A9 and CCTγ showed promise as novel diagnostic markers for CCA.

Biomarkers in Exhaled Breath Condensate and Serum of Chronic Obstructive Pulmonary Disease and Non-Small-Cell Lung Cancer

Chronic obstructive pulmonary disease (COPD) and lung cancer are leading causes of deaths worldwide which are associated with chronic inflammation and oxidative stress. Lung cancer, in particular, has a very high mortality rate due to the characteristically late diagnosis. As such, identification of novel biomarkers which allow for early diagnosis of these diseases could improve outcome and survival rate. Markers of oxidative stress in exhaled breath condensate (EBC) are examples of potential diagnostic markers for both COPD and non-small-cell lung cancer (NSCLC). They may even be useful in monitoring treatment response. In the serum, S100A8, S100A9, and S100A12 of the S100 proteins are proinflammatory markers. They have been indicated in several inflammatory diseases and cancers including secondary metastasis into the lung. It is highly likely that they not only have the potential to be diagnostic biomarkers for NSCLC but also prognostic indicators and therapeutic targets.

Current status of biomarkers for prostate cancer

Prostate cancer (PCa) is a leading cause of cancer-related death of men globally. Since its introduction, there has been intense debate as to the effectiveness of the prostate specific antigen (PSA) test as a screening tool for PCa. It is now evident that the PSA test produces unacceptably high rates of false positive results and is not prognostic. Here we review the current status of molecular biomarkers that promise to be prognostic and that might inform individual patient management. It highlights current efforts to identify biomarkers obtained by minimally invasive methods and discusses current knowledge with regard to gene fusions, mRNA and microRNAs, immunology, and cancer-associated microparticles.

Common interactions between S100A4 and S100A9 defined by a novel chemical probe

S100A4 and S100A9 proteins have been described as playing roles in the control of tumor growth and metastasis. We show here that a chemical probe, oxyclozanide (OX), selected for inhibiting the interaction between S100A9 and the receptor for advanced glycation end-products (RAGE) interacts with both S100A9 and S100A4. Furthermore, we show that S100A9 and S100A4 interact with RAGE and TLR4; interactions that can be inhibited by OX. Hence, S100A4 and S100A9 display similar functional elements despite their primary sequence diversity. This was further confirmed by showing that S100A4 and S100A9 dimerize both in vitro and in vivo. All of these interactions required levels of Zn⁺⁺ that are found in the extracellular space but not intracellularly. Interestingly, S100A4 and S100A9 are expressed by distinct CD11b⁺ subpopulations both in healthy animals and in animals with either inflammatory disease or tumor burden. The functions of S100A9 and S100A4 described in this paper, including heterodimerization, may therefore reflect S100A9 and S100A4 that are released into the extra-cellular milieu.

S100A8 and S100A9 are associated with colorectal carcinoma progression and contribute to colorectal carcinoma cell survival and migration via Wnt/β-catenin pathway

Background and Objective

S100A8 and S100A9, two members of the S100 protein family, have been reported in association with the tumor cell differentiation and tumor progression. Previous study has showed that their expression in stromal cells of colorectal carcinoma (CRC) is associated with tumor size. Here, we investigated the clinical significances of S100A8 and S100A9 in tumor cells of CRC and their underlying molecular mechanisms.

Methods

Expression of S100A8 and S100A9 in colorectal carcinoma and matching distal normal tissues were measured by reverse transcriptase polymerase chain reaction (RT-PCR), immunohistochemistry and western blot. CRC cell lines treated with the recombinant S100A8 and S100A9 proteins were used to analyze the roles and molecular mechanisms of the two proteins in CRC in vitro.

Results

S100A8 and S100A9 were elevated in more than 50% of CRC tissues and their expression in tumor cells was associated with differentiation, Dukes stage and lymph node metastasis. The CRC cell lines treatment with recombinant S100A8 and S100A9 proteins promoted the viability and migration of CRC cells. Furthermore, the two recombinant proteins also resulted in the increased levels of β-catenin and its target genes c-myc and MMP7. β-catenin over-expression in CRC cells by Adβ-catenin increased cell viability and migration. β-catenin knock-down by Adsiβ-catenin reduced cell viability and migration. Furthermore, β-catenin knockdown also partially abolished the promotive effects of recombinant S100A8 and S100A9 proteins on the viability and migration of CRC cells.

Conclusions

Our work demonstrated that S100A8 and S100A9 are linked to the CRC progression, and one of the underlying molecular mechanisms is that extracellular S100A8 and S100A9 proteins contribute to colorectal carcinoma cell survival and migration via Wnt/β-catenin pathway.

Human S100A9 protein is stabilized by inflammatory stimuli via the formation of proteolytically-resistant homodimers

S100A8 and S100A9 are Ca(2+)-binding proteins that are associated with acute and chronic inflammation and cancer. They form predominantly heterodimers even if there are data supporting homodimer formation. We investigated the stability of the heterodimer in myeloid and S100A8/S100A9 over-expressing COS cells. In both cases, S100A8 and S100A9 proteins were not completely degraded even 48 hrs after blocking protein synthesis. In contrast, in single transfected cells, S100A8 protein was completely degraded after 24 h, while S100A9 was completely unstable. However, S100A9 protein expression was rescued upon S100A8 co-expression or inhibition of proteasomal activity. Furthermore, S100A9, but not S100A8, could be stabilized by LPS, IL-1β and TNFα treatment. Interestingly, stimulation of S100A9-transfected COS cells with proteasomal inhibitor or IL-1β lead to the formation of protease resistant S100A9 homodimers. In summary, our data indicated that S100A9 protein is extremely unstable but can be rescued upon co-expression with S100A8 protein or inflammatory stimuli, via proteolytically resistant homodimer formation. The formation of S100A9 homodimers by this mechanism may constitute an amplification step during an inflammatory reaction.

Risk assessment, disease prevention and personalised treatments in breast cancer: is clinically qualified integrative approach in the horizon?

Breast cancer is a multifactorial disease. A spectrum of internal and external factors contributes to the disease promotion such as a genetic predisposition, chronic inflammatory processes, exposure to toxic compounds, abundant stress factors, a shift-worker job, etc. The cumulative effects lead to high incidence of breast cancer in populations worldwide. Breast cancer in the USA is currently registered with the highest incidence rates amongst all cancer related patient cohorts. Currently applied diagnostic approaches are frequently unable to recognise early stages in tumour development that impairs individual outcomes. Early diagnosis has been demonstrated to be highly beneficial for significantly enhanced therapy efficacy and possibly full recovery. Actual paper shows that the elaboration of an integrative diagnostic approach combining several levels of examinations creates a robust platform for the reliable risk assessment, targeted preventive measures and more effective treatments tailored to the person in the overall task of breast cancer management. The levels of examinations are proposed, and innovative technological approaches are described in the paper. The absolute necessity to create individual patient profiles and extended medical records is justified for the utilising by routine medical services. Expert recommendations are provided to promote further developments in the field.

Different expression of S100A8 in malignant and benign gallbladder diseases

BACKGROUND

Proteomic analysis is a powerful tool for complete establishment of protein expression. Comparative proteomic analysis of human bile from malignant and benign gallbladder diseases may be helpful in research into gallbladder cancer.

AIMS

Our objective was to establish biliary protein content for gallbladder cancer, gallbladder adenoma, and chronic calculous cholecystitis for comparative proteomic analysis.

METHODS

Bile samples were collected from patients with gallbladder cancer, gallbladder adenoma, and chronic calculous cholecystitis. Peptides of biliary proteins were separated by two-dimensional liquid chromatography then identified by tandem mass spectrometry.

RESULTS

Up to 544, 221, and 495 unique proteins were identified in bile samples from gallbladder cancer, gallbladder adenoma, and chronic calculous cholecystitis. Forty-three, 16, and 28 proteins with more than one unique peptide, respectively, were identified in the three groups. Among these, 30 proteins including S100A8 were overexpressed in gallbladder cancer, compared with benign gallbladder diseases. We also confirmed, by immunohistochemical analysis, that S100A8 is more abundant in tumor-infiltrating immune cells in cancerous tissue.

CONCLUSIONS

Compared with benign gallbladder diseases, consistently elevated S100A8 levels in malignant gallbladder bile and tissue indicate that gallbladder cancer is an inflammation-associated cancer. S100A8 may be a biomarker for gallbladder cancer.

CD11b+Ly6C++Ly6G- cells show distinct function in mice with chronic inflammation or tumor burden

Background

S100A9 has been shown to be important for the function of so called Myeloid Derived Suppressor Cells (MDSC). Cells with a similar phenotype are also involved in pro-inflammatory processes, and we therefore wanted to investigate the gene expression and function of these cells in animals that were either subjected to chronic inflammation, or inoculated with tumors.

Methods

CD11b⁺Ly6C⁺⁺ and Ly6G⁺ cells were isolated from spleen, tumor tissue or inflammatory granulomas. S100A9, Arginase 1 and iNOS gene expression in the various CD11b⁺ cell populations was analyzed using Q-PCR. The suppressive activity of the CD11b⁺ cell populations from different donors was studied in co-culture experiments.

Results

S100A9 was shown to be expressed mainly in splenic CD11b⁺Ly6C⁺G⁺ cells both at the RNA and protein level. Arginase I and iNOS expression could be detected in both CD11b⁺Ly6C⁺Ly6G⁺ and CD11b⁺Ly6C⁺G^-/C⁺⁺G^- derived from tumors or a site of chronic inflammation, but was very low in the same cell populations isolated from the spleen. CD11b⁺ cells isolated from mice with peritoneal chronic inflammation were able to stimulate T lymphocytes, while CD11b⁺ cells from mice with peritoneal tumors suppressed T cell growth.

Conclusion

An identical CD11b⁺Ly6C⁺⁺G^- cell population appears to have the ability to adopt immune stimulatory or immune suppressive functions dependent on the presence of a local inflammatory or tumor microenvironment. Thus, there is a functional plasticity in the CD11b⁺Ly6C⁺⁺G^- cell population that cannot be distinguished with the current molecular markers.

Induction of nuclear factor-κB responses by the S100A9 protein is Toll-like receptor-4-dependent

Interactions between danger-associated molecular patterns (DAMP) and pathogen-associated molecular patterns (PAMP) and pattern recognition receptors such as Toll-like receptors (TLRs) are critical for the regulation of the inflammatory process via activation of nuclear factor-κB (NF-κB) and cytokine secretion. In this report, we investigated the capacity of lipopolysaccharide (LPS) -free S100A9 (DAMP) protein to activate human and mouse cells compared with lipoprotein-free LPS (PAMP). First, we showed that LPS and S100A9 were able to increase NF-κB activity followed by increased cytokine and nitric oxide (NO) secretion both in human THP-1 cells and in mouse bone marrow-derived dendritic cells. Surprisingly, although S100A9 triggered a weaker cytokine response than LPS, we found that S100A9 more potently induced IκBα degradation and hence NF-κB activation. Both the S100A9-induced response and the LPS-induced response were completely absent in TLR4 knockout mice, whereas it was only slightly affected in RAGE knockout mice. Also, we showed that LPS and S100A9 NF-κB induction were strongly reduced in the presence of specific inhibitors of TLR-signalling. Chloroquine reduced S100A9 but not LPS signalling, indicating that S100A9 may need to be internalized to be fully active as a TLR4 inducer. This was confirmed using A488-labelled S100A9 that was internalized in THP-1 cells, showing a raise in fluorescence after 30 min at 37°. Chloroquine treatment significantly reduced the fluorescence. In summary, our data indicate that both human and mouse S100A9 are TLR4 agonists. Importantly, S100A9 induced stronger NF-κB activation albeit weaker cytokine secretion than LPS, suggesting that S100A9 and LPS activated NF-κB in a qualitatively distinct manner.

Review of S100A9 biology and its role in cancer

S100A9 is a calcium binding protein with multiple ligands and post-translation modifications that is involved in inflammatory events and the initial development of the cancer cell through to the development of metastatic disease. This review has a threefold purpose: 1) describe the S100A9 structural elements important for its biological activity, 2) describe the S100A9 biology in the context of the immune system, and 3) illustrate the role of S100A9 in the development of malignancy via interactions with the immune system and other cellular processes.

Calprotectin: a novel biomarker for the diagnosis of pleural effusion

Background:

Novel non-invasive biomarkers for the precise diagnosis of malignancy in pleural effusion (PE) are needed. The aim of this study was to determine the diagnostic accuracy of calprotectin for predicting malignancy in patients with exudative PE.

Methods:

Calprotectin concentration was measured in 156 individuals diagnosed with exudative PE (67 malignant and 89 benign). Calprotectin accuracy for discriminating between malignant and benign PE was evaluated using receiver operating characteristic (ROC) curves. Univariate and multivariate logistic regression were performed to test the association between calprotectin levels and malignant PE.

Results:

Calprotectin levels were significantly lower in malignant pleural fluid (257.2 ng ml⁻¹, range: 90.7–736.4) than benign effusions (2627.1 ng ml⁻¹, range: 21–9530.1). The area under the curve was 0.963. A cutoff point of ⩽736.4 ng ml⁻¹ rendered a sensitivity of 100%, with a specificity of 83.15%, which could prove useful to delimit those patients with negative cytology tests that should be referred for more invasive diagnostic procedures. Logistic regression demonstrated a strong association between calprotectin and malignancy (adjusted OR 663.14).

Conclusion:

Calprotectin predicts malignancy in pleural fluid with high accuracy and could be a good complement to cytological methods.

MALDI-imaging segmentation is a powerful tool for spatial functional proteomic analysis of human larynx carcinoma

PURPOSE

For several decades, conventional histological staining and immunohistochemistry (IHC) have been the main tools to visualize and understand tissue morphology and structure. IHC visualizes the spatial distribution of individual protein species directly in tissue. However, a specific antibody is required for each protein, and multiplexing capabilities are extremely limited, rarely visualizing more than two proteins simultaneously. With the recent emergence of matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-imaging), it is becoming possible to study more complex proteomic patterns directly in tissue. However, the analysis and interpretation of large and complex MALDI-imaging data requires advanced computational methods. In this paper, we show how the recently introduced method of spatial segmentation can be applied to analysis and interpretation of a larynx carcinoma section and compare the spatial segmentation with the histological annotation of the same tissue section.

METHODS

Matrix-assisted laser desorption/ionization imaging is a label-free spatially resolved analytical technique, which allows detection and visualization of hundreds of proteins at once. Spatial segmentation of the MALDI-imaging data by clustering of spectra by their similarity was performed, automatically generating a spatial segmentation map of the tissue section, where regions of similar proteomic patterns were highlighted. The tissue was stained with the hematoxylin and eosin (H&E), histopathologically analyzed and annotated. The segmentation map was interpreted after its overlay with the H&E microscopy image.

RESULTS

The automatically generated segmentation map exhibits high correspondence to the detailed histological annotation of the larynx carcinoma tissue section. By superimposing, the segmentation map based on the proteomic profiles with H&E-stained microscopic images, we demonstrate precise localization of complex and histopathologically relevant tissue features in an automated way.

CONCLUSIONS

The combination of MALDI-imaging and automatic spatial segmentation is a useful approach in analyzing carcinoma tissue and provides a deeper insight into the functional proteomic organization of the respective tissue.

Presence of S100A9-positive inflammatory cells in cancer tissues correlates with an early stage cancer and a better prognosis in patients with gastric cancer

Background

S100A9 was originally discovered as a factor secreted by inflammatory cells. Recently, S100A9 was found to be associated with several human malignancies. The purpose of this study is to investigate S100A9 expression in gastric cancer and explore its role in cancer progression.

Methods

S100A9 expression in gastric tissue samples from 177 gastric cancer patients was assessed by immunohistochemistry. The expression of its dimerization partner S100A8 and the S100A8/A9 heterodimer were also assessed by the same method. The effect of exogenous S100A9 on motility of gastric cancer cells AGS and BGC-823 was then investigated.

Results

S100A9 was specifically expressed by inflammatory cells such as macrophages and neutrophils in human gastric cancer and gastritis tissues. Statistical analysis showed that a high S100A9 cell count (> = 200) per 200x magnification microscopic field in cancer tissues was predictive of early stage gastric cancer. High S100A9-positive cell count was negatively correlated with lymph node metastasis (P = 0.009) and tumor invasion (P = 0.011). S100A9 was identified as an independent prognostic predictor of overall survival of patients with gastric cancer (P = 0.04). Patients with high S100A9 cell count were with favorable prognosis (P = 0.021). Further investigation found that S100A8 distribution in human gastric cancer tissues was similar to S100A9. However, the number of S100A8-positive cells did not positively correlate with patient survival. The inflammatory cells infiltrating cancer were S100A8/A9 negative, while those in gastritis were positive. Furthermore, exogenous S100A9 protein inhibited migration and invasion of gastric cancer cells.

Conclusions

Our results suggested S100A9-positive inflammatory cells in gastric cancer tissues are associated with early stage of gastric cancer and good prognosis.

Periostin, a stroma-associated protein, correlates with tumor invasiveness and progression in nasopharyngeal carcinoma

Recently, the tumor microenvironment is increasingly recognized as playing an important role in cancer proliferation, invasion, and metastasis. To screen stroma-associated proteins involved in nasopharyngeal carcinoma (NPC) carcinogenesis, laser capture microdissection (LCM) and quantitative proteomic analysis were employed to assess different protein expression of the stroma between NPC and normal nasopharyngeal mucosa (NNM). In this study, periostin was identified to be significantly up-regulated in NPC stroma compared with NNM stroma and the result was further confirmed by Western blotting. Immunohistochemistry showed that over-expression of periostin was frequently observed in the stroma of NPC and matched lymph node metastases (LNM) compared with the stroma of NNM. Statistical analysis showed over-expression of periostin was significantly associated with advanced clinical stage (P < 0.001) and lymph node metastasis (P < 0.001) and decreased overall survival (P < 0.001) in NPC. Cox regression analysis indicated over-expression of periostin was an independent prognostic factor. Furthermore, ectopic expression of periostin was used to examine its effect on invasiveness of NPC cell in vitro and the result showed that periostin was able to promote invasiveness of NPC cell. In conclusion, periostin expression is correlated with tumor stage, lymph node metastasis, and patient survival. Periostin is a potential biomarker for the differentiation and prognosis of NPC, and it might play an important role in the progression of NPC.

Elevated levels of proliferating and recently migrated tumor-associated macrophages confer increased aggressiveness and worse outcomes in breast cancer

PURPOSE

Macrophages play a major role in inflammatory processes and have been associated with poor prognosis in a variety of cancers, including breast cancer. Previously, we investigated the relationship of a subset of tumor-associated macrophages (PCNA(+) TAMs) with clinicopathologic characteristics of breast cancer. We reported that high PCNA(+) TAM counts were associated with hormone receptor (HR)-negative, high-grade tumors and early recurrence. To further understand the significance of elevated PCNA(+) TAMs and the functionality of TAMs, we examined the expression of S100A8/S100A9 with the antibody Mac387. The heterodimeric S100A8/S100A9 complex plays a role in inflammation and is increased in several cancer types.

METHODS

We performed immunohistochemistry using the Mac387 antibody on 367 invasive human breast cancer cases. Results were compared to previous PCNA(+) TAM counts and were correlated with patient outcomes adjusting for HR status and histologic grade.

RESULTS

Like PCNA(+) TAMs, high Mac387 counts were associated with HR negativity, high tumor grade, younger age, and decreased recurrence-free survival. Mac387, however, appears to identify both a subset of macrophages and a subset of tumor cells. The concordance between Mac387 and PCNA(+) TAM counts was low and cases that had both high Mac387 and high PCNA(+) TAMs counts had a stronger association with early recurrence.

CONCLUSIONS

The presence of high numbers of PCNA(+) TAMs and Mac387-positive cells in breast cancers with poor outcomes may implicate a subset of TAMs in breast cancer pathogenesis, and may ultimately serve to develop potential cellular targets for therapeutic interventions.

Low concentration of S100A8/9 promotes angiogenesis-related activity of vascular endothelial cells: bridges among inflammation, angiogenesis, and tumorigenesis?

Previous studies showed that several members of the S100A family are involved in neovascularization and tumor development. This study checked whether low concentrations of S100A8 or S100A9 has any effect on the behaviour of vascular endothelial cells. A human umbilical vascular endothelial cell (HUVEC) line was used to measure vascular endothelial cell bioactivity related to angiogenesis, such as cell proliferation, migration, and vessel formation. In the low concentration range up to 10 μg/mL, either each alone or in combination, S100A8 and S100A9 proteins promoted proliferation of HUVEC cells in a dose-dependent manner. The presence of both proteins in culture showed additive effects over each single protein. Both proteins enhanced HUVEC cells to migrate across the transwell membrane and to form tube-like structures on the Matrigel surface. When mixed in Matrigel and injected subcutaneously in Balb/c mice, both proteins increased vessel development in the gel plugs. Microarray assay of HUVEC cells treated with 10 μg/mL S100A8 revealed that ribosome pathway, pathogenic Escherichia coli infection pathway, apoptosis, and stress response genes were modulated by S100A8 treatment. We propose that S100A8 and S100A9 proteins from either infiltrating inflammatory cells or tumor cells play an important role in the interplay among inflammation, angiogenesis, and tumorigenesis.

Hypoxia and HIF-1 increase S100A8 and S100A9 expression in prostate cancer

S100A8 and S100A9, two heterodimer-forming members of the cytosolic S100 Ca(2+) signaling protein family, are overexpressed in various cancer types, including prostate cancer. They act as proinflammatory danger signals when secreted to the extracellular space and are thought to play an important role during tumorigenesis, affecting inflammatory processes, proliferation, invasion and metastasis of tumor cells. Despite this fact, little is known about tumor environmental factors influencing S100A8/A9 expression. The aim of this study was to test the effect of hypoxia and its master transcriptional regulator hypoxia-inducible factor 1 (HIF-1) on S100A8/A9 expression. Hypoxia treatment resulted in induction of S100A8/A9 protein and mRNA expression in prostate epithelial BPH-1 cells, the latter was also confirmed in the prostate cancer cell lines PC-3 and DU-145. Furthermore, overexpression of HIF-1α caused increase in S100A8/A9 protein and mRNA expression as well as secretion. Functional hypoxia response elements mediating promoter activation on HIF-1α overexpression were identified within the S100A8 and S100A9 promoters using promoter luciferase reporter constructs. Binding of HIF-1α to S100A8 and S100A9 promoters was confirmed by chromatin immunoprecipitation. Immunohistochemical analysis of a prostate cancer tissue array showed clear correlation of S100A8 and S100A9 with HIF-1α expression. Multivariate proportional hazard analysis revealed association of high S100A9 level with time to prostate cancer recurrence. In conclusion, we identified hypoxia and HIF-1 as novel regulators of S100A8/A9 expression in prostate cancer. S100A9 might be useful as prognostic marker for prostate cancer recurrence after radical prostatectomy.

S100A9 interaction with TLR4 promotes tumor growth

By breeding TRAMP mice with S100A9 knock-out (S100A9^−/−) animals and scoring the appearance of palpable tumors we observed a delayed tumor growth in animals devoid of S100A9 expression. CD11b⁺ S100A9 expressing cells were not observed in normal prostate tissue from control C57BL/6 mice but were readily detected in TRAMP prostate tumors. Also, S100A9 expression was observed in association with CD68⁺ macrophages in biopsies from human prostate tumors. Delayed growth of TRAMP tumors was also observed in mice lacking the S100A9 ligand TLR4. In the EL-4 lymphoma model tumor growth inhibition was observed in S100A9^−/− and TLR4^−/−, but not in RAGE^−/− animals lacking an alternative S100A9 receptor. When expression of immune-regulating genes was analyzed using RT-PCR the only common change observed in mice lacking S100A9 and TLR4 was a down-regulation of TGFβ expression in splenic CD11b⁺ cells. Lastly, treatment of mice with a small molecule (ABR-215050) that inhibits S100A9 binding to TLR4 inhibited EL4 tumor growth. Thus, S100A9 and TLR4 appear to be involved in promoting tumor growth in two different tumor models and pharmacological inhibition of S100A9-TLR4 interactions is a novel and promising target for anti-tumor therapies.

Pro-inflammatory S100A8 and S100A9 proteins: self-assembly into multifunctional native and amyloid complexes

S100A8 and S100A9 are EF-hand Ca²⁺ binding proteins belonging to the S100 family. They are abundant in cytosol of phagocytes and play critical roles in numerous cellular processes such as motility and danger signaling by interacting and modulating the activity of target proteins. S100A8 and S100A9 expression levels increased in many types of cancer, neurodegenerative disorders, inflammatory and autoimmune diseases and they are implicated in the numerous disease pathologies. The Ca²⁺ and Zn²⁺-binding properties of S100A8/A9 have a pivotal influence on their conformation and oligomerization state, including self-assembly into homo- and heterodimers, tetramers and larger oligomers. Here we review how the unique chemical and conformational properties of individual proteins and their structural plasticity at the quaternary level account for S100A8/A9 functional diversity. Additional functional diversification occurs via non-covalent assembly into oligomeric and fibrillar amyloid complexes discovered in the aging prostate and reproduced in vitro. This process is also regulated by Ca²⁺and Zn²⁺-binding and effectively competes with the formation of the native complexes. High intrinsic amyloid-forming capacity of S100A8/A9 proteins may lead to their amyloid depositions in numerous ailments characterized by their elevated expression patterns and have additional pathological significance requiring further thorough investigation.

S100A8/A9 aggravates post-ischemic heart failure through activation of RAGE-dependent NF-κB signaling

The extracellular heterodimeric protein S100A8/A9 activates the innate immune system through activation of the receptor of advanced glycation end products (RAGE) and Toll-like receptors. As activation of RAGE has recently been associated with sustained myocardial inflammation and heart failure (HF) we studied the role of S100A8/A9 in the development of post-ischemic HF. Hypoxia led to sustained induction of S100A8/A9 accompanied by increased nuclear factor (NF-)κB binding activity and increased expression of pro-inflammatory cytokines in cardiac fibroblasts and macrophages. Knockdown of either S100A8/A9 or RAGE rescued the induction of pro-inflammatory cytokines and NF-κB activation after hypoxia. In a murine model of post-ischemic HF both cardiac RNA and protein levels of S100A8/A9 were elevated as soon as 30 min after hypoxia with sustained activation up to 28 days after ischemic injury. Treatment with recombinant S100A8/A9 resulted in reduced cardiac performance following ischemia/reperfusion. Chimera experiments after bone marrow transplantation demonstrated the importance of RAGE expression on immune cells for their recruitment to the injured myocardium aggravating post-ischemic heart failure. Signaling studies in isolated ventricles indicated that MAP kinases JNK, ERK1/2 as well as NF-κB mediate signals downstream of S100A8/A9-RAGE in post-ischemic heart failure. Interestingly, cardiac performance was not affected by administration of S100A8/A9 in RAGE(-/-)-mice, which demonstrated significantly improved cardiac recovery compared to WT-mice. Our study provides evidence that sustained activation of S100A8/A9 critically contributes to the development of post-ischemic HF driving the progressive course of HF through activation of RAGE.

Identification of stromal proteins overexpressed in nodular sclerosis Hodgkin lymphoma

Hodgkin lymphoma (HL) represents a category of lymphoid neoplasms with unique features, notably the usual scarcity of tumour cells in involved tissues. The most common subtype of classical HL, nodular sclerosis HL, characteristically comprises abundant fibrous tissue stroma. Little information is available about the protein composition of the stromal environment from HL. Moreover, the identification of valid protein targets, specifically and abundantly expressed in HL, would be of utmost importance for targeted therapies and imaging, yet the biomarkers must necessarily be accessible from the bloodstream. To characterize HL stroma and to identify potentially accessible proteins, we used a chemical proteomic approach, consisting in the labelling of accessible proteins and their subsequent purification and identification by mass spectrometry. We performed an analysis of potentially accessible proteins in lymph node biopsies from HL and reactive lymphoid tissues, and in total, more than 1400 proteins were identified in 7 samples. We have identified several extracellular matrix proteins overexpressed in HL, such as versican, fibulin-1, periostin, and other proteins such as S100-A8. These proteins were validated by immunohistochemistry on a larger series of biopsy samples, and bear the potential to become targets for antibody-based anti-cancer therapies.

S100A8 and S100A9: new insights into their roles in malignancy

Recent studies have highlighted key roles played by non-neoplastic host cells of the tumor microenvironment, and by secreted factors from tumor and host cells, in promoting malignancy. In this regard, damage-associated molecular pattern (DAMP) molecules such as S100A8 and S100A9, with well-known functions in inflammation, have been increasingly recognized not only as markers, but also as new candidates with important roles in modulating tumor growth and metastasis. This review focuses on our current understanding of the pro- and anti-tumorigenic functions of S100A8 and S100A9. Elucidating molecular pathways mediated by these proteins promises to provide potential novel targets for the development of cancer therapeutics and to establish valid biomarkers to identify early stages of tumor progression.

Analysis of plasma calprotectin and polymorphisms of S100A8 in patients with aggressive periodontitis

BACKGROUND AND OBJECTIVE

Calprotectin is an important proinflammatory mediator in various inflammatory diseases and is composed of two subunits (S100A8 and S100A9). However, the level of calprotectin in plasma of patients with aggressive periodontitis and its relationship with gene polymorphisms of S100A8 are unclear.

MATERIAL AND METHODS

The plasma concentrations of calprotectin were measured, using an enzyme immunoassay, in 139 patients with aggressive periodontitis and in 88 periodontally healthy control subjects. These patients were genotyped for the rs3795391 and rs3806232 polymorphisms of S100A8.

RESULTS

The plasma concentration of calprotectin in patients with aggressive periodontitis was significantly higher than in controls (2.17 mg/L vs. 1.72 mg/L, respectively, p = 0.001). The percentage of the AA genotype of S100A8 rs3795391 was significantly higher in patients than in controls (82% vs. 69.3%, respectively, p = 0.027), while the frequency of the allele G was decreased among patients compared with controls (9.6% vs. 16.1%, respectively, p = 0.036), which was especially apparent in men (rs3795391 genotype, p = 0.005; rs3795391 allele, p = 0.015). The mean probing depth in patients carrying the AA genotype was significantly higher than that of patients carrying the GA + GG genotype of two polymorphisms of S100A8 (rs3795391, p = 0.035; rs3806232, p = 0.040), whereas the levels of calprotectin between different genotypes were not significantly different (rs3795391, p = 0.11; rs3806232, p = 0.15).

CONCLUSION

These findings indicate that aggressive periodontitis is associated with elevated levels of plasma calprotectin and that gene polymorphisms of S100A8 may influence the susceptibility and severity of aggressive periodontitis.

Prognostic impact of S100A9 overexpression in non-small cell lung cancer

S100 proteins have been implicated in the progression and metastasis of several cancers. Among the S100 family, S100A9 is reportedly expressed in non-small cell lung cancer (NSCLC), though the clinical significance and prognostic value of S100A9 expression in NSCLC remains unclear. The aim of the present study was to examine the relationship between S100A9 expression and prognosis in NSCLC patients. S100A9 expression was evaluated by immunohistochemical staining. Seventy patients with NSCLC who had undergone lung resection were enrolled in the study. Overexpression of S100A9 was observed in 38 (54.3%) patients. Kaplan-Meier analysis showed that, following surgery, patients overexpressing S100A9 had a significantly lower 5-year overall survival rate than patients with weak or no expression of S100A9 (P=0.005). This finding was also observed in pathological stage IA patients (P=0.03). Multivariate Cox regression analysis revealed overexpression of S100A9 to be an independent factor predictive of poor disease outcome (hazard ratio, 0.3; 95% confidence interval, 0.1-0.8; P=0.02). Our results suggest that overexpression of S100A9 is associated with a poor prognosis among NSCLC patients and could serve as a marker identifying patients who are at high risk, even at an early pathological stage.

Identification of annexin A1 as a proinvasive and prognostic factor for lung adenocarcinoma

Metastasis is the most common cause of death in lung cancer patients and is a major obstacle to the successful treatment. To discover novel metastasis-related proteins in lung adenorcinoma (AdC), quantitative proteomic analysis was performed between primary lung AdC tissues with (LNM AdC) and without lymph node metastasis (non-LNM AdC). In this study, annexin A1 was identified to be significantly up-regulated in LNM AdC compared with non-LNM AdC. Immunohistochemistry showed that annexin A1 over-expression was frequently observed in LNM AdCs and matched lymph node metastases compared with non-LNM AdCs. Annexin A1 over-expression was significantly associated with advanced clinical stage (P < 0.05) and lymph node metastasis (P < 0.05) and increased relapse rate (P < 0.05) and decreased overall survival (P < 0.05) in lung AdCs. Cox regression analysis indicated annexin A1 over-expression was an independent prognostic factor. Furthermore, suppression of annexin A1 expression by siRNA interference significantly inhibited the invasion ability of lung adenocarcinoma cell A549 in vitro. In conclusion, annexin A1 expression correlated with tumor stage, lymph node metastasis, relapse, and patient survival. Annexin A1 is proposed to function importantly in the progression of lung AdC.

A four-gene signature predicts disease progression in muscle invasive bladder cancer

There are no reliable criteria to handle disease progression of muscle invasive bladder cancer (MIBC), which strongly influences patient survival. Therefore, an accurate predicting method to identify progressive MIBC patients is greatly needed. The aim of this study was to identify a genetic signature associated with disease progression in MIBC. To address this issue, we analyzed three independent cohorts (a training set, test set 1 and test set 2) comprising a total of 128 MIBC patients. Microarray gene expression profiling, including gene network analysis, was performed in the training set to identify a gene expression signature associated with disease progression. The prognostic value of the signature was validated in test set 1 and test set 2 by microarray and real-time reverse transcriptase polymerase chain reaction (RT-PCR), respectively. The determination of gene expression patterns by microarray data analysis identified 1,320 genes associated with disease progression. Gene network analysis of the 1,320 genes suggested that IL1B, S100A8, S100A9 and EGFR were important mediators of MIBC progression. We validated this putative four-gene signature in two independent cohorts (log-rank test, P < 0.05 each, respectively) and estimated the predictive value of the signature by multivariate Cox regression analysis (hazard ratio [HR], 6.24; 95% confidence interval [CI], 1.58-24.61; P = 0.009). Finally, signature-based stratification demonstrated that the four-gene signature was an independent predictor of MIBC progression. In conclusion, a molecular signature defined by four genes represents a promising diagnostic tool for the identification of MIBC patients at high risk of progression.

Analysis of differential gene expression by fiber-optic BeadArray and pathway in prolactinomas

Prolactinomas are the most common secretory pituitary tumors; however, their pathogenesis is unclear. In order to explore the pathogenesis of prolactinomas, we used fiber-optic BeadArray to examine gene expression profiles in five prolactinomas compared with three normal pituitaries. Three down-regulated genes and one up-regulated gene were chosen for validation by quantitative real-time reverse-transcription polymerase chain reaction. We then performed pathway analysis on the identified differentially expressed genes using the Kyoto Encyclopedia of Genes and Genomes. Array analysis showed significant increases in the expression of 27 genes and 3 expressed sequence tags (ESTs), and decreases in 182 genes and 9 ESTs, including HIG1 domain family, member 1B, S100 calcium binding protein A9, angiopoietin 2, interleukin 8, hydroxyprostaglandin dehydrogenase 15-(NAD), suppression of tumorigenicity18, and WNT inhibitory factor 1. Pathway analysis showed that the P53 and GnRH signaling pathways may play an important role in tumorigenesis of prolactinomas. Our data suggest fiber-optic BeadArray combined with pathway analysis of differential gene expression profile appears to be a valid approach for investigating the pathogenesis of tumors.

Proteomic identification of salivary transferrin as a biomarker for early detection of oral cancer

Oral cancer has a low five-year survival rate. Early detection of oral cancer could reduce the mortality and morbidity associated with this disease. Saliva, which can be sampled non-invasively and is less complex than blood, is a good potential source of oral cancer biomarkers. Proteomic analysis of saliva from oral cancer patients and control subjects was performed to identify salivary biomarkers of early stage oral cancer in humans. The protein profile of pooled salivary samples from patients with oral squamous cell carcinoma (OSCC) or OSCC-free control subjects was analyzed using two-dimensional gel electrophoresis (2DE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analyses. Potential biomarkers were verified by Western blotting and ELISA assays. Transferrin levels were elevated in the saliva of OSCC patients as determined using 2DE followed by MALDI-TOF MS and confirmed by MALDI-TOF/TOF MS, Western blotting and ELISA. The increase in salivary transferrin levels in OSCC patients strongly correlated with the size and stage of the tumor. The area under the receiver-operating characteristics curves showed that salivary transferrin-based ELISA was highly specific, sensitive and accurate for the early detection of oral cancer. We have identified salivary transferrin as a biomarker for the detection of early stage oral cancer. This finding provides a promising basis for the development of a non-invasive diagnostic test for early stage oral cancer.

Research resource: estrogen-driven prolactin-mediated gene-expression networks in hormone-induced prostatic intraepithelial neoplasia

Cotreatment with testosterone (T) and 17β-estradiol (E2) is an established regimen for inducing of prostatic intraepithelial neoplasia (PIN) and prostate cancer in rodent models. We previously used the pure antiestrogen ICI 182,780 (ICI) and bromocriptine, a dopamine receptor agonist, to inhibit PIN induction and systemic hyperprolactinemia in Noble rats and found that the carcinogenic action of T+E2 is mediated directly by the effects of E2 on the prostate and/or indirectly via E2-induced hyperprolactinemia. In this study, we delineate the specific action(s) of E2 and prolactin (PRL) in early prostate carcinogenesis by an integrated approach combining global transcription profiling, gene ontology, and gene-network mapping. We identified 2504 differentially expressed genes in the T+E2-treated lateral prostate. The changes in expression of a subset of 1990 genes (∼80%) were blocked upon cotreatment with ICI and bromocriptine, respectively, whereas those of 262 genes (∼10%) were blocked only by treatment with ICI, suggesting that E2-induced pituitary PRL is the primary mediator of the prostatic transcriptional response to the altered hormone milieu. Bioinformatics analyses identified hormone-responsive gene networks involved in immune responses, stromal tissue remodeling, and the ERK pathway. In particular, our data suggest that IL-1β may mediate, at least in part, hormone-induced changes in gene expression during PIN formation. Together, these data highlight the importance of pituitary PRL in estrogen-induced prostate tumorigenesis. The identification of both E2- and pituitary PRL-responsive genes provides a comprehensive resource for future investigations of the complex mechanisms by which changes in the endocrine milieu contribute to prostate carcinogenesis in vivo.

Depicting the spatial distribution of proteins in human tumor tissue combining SELDI and MALDI imaging and immunohistochemistry

Carcinoma tissue consists of not only tumor cells but also fibroblasts, endothelial cells or vascular structures, and inflammatory cells forming the supportive tumor stroma. Therefore, the spatial distribution of proteins that promote growth and proliferation in these complex functional units is of high interest. Matrix-assisted laser desorption/ionization imaging mass spectrometry is a newly developed technique that generates spatially resolved profiles of protein signals directly from thin tissue sections. Surface-enhanced laser desorption/ionization mass spectrometry (MS)combined with tissue microdissection allows analysis of defined parts of the tissue with a higher sensitivity and a broader mass range. Nevertheless, both MS-based techniques have a limited spatial resolution. IHC is a technique that allows a resolution down to the subcellular level. However, the detection and measurement of a specific protein expression level is possible only by semiquantitative methods. Moreover, prior knowledge about the identity of the proteins of interest is necessary. In this study, we combined all three techniques to gain highest spatial resolution, sensitivity, and quantitative information. We used frozen tissue from head and neck tumors and chose two exemplary proteins (HNP1-3 and S100A8) to highlight the advantages and disadvantages of each technique. It could be shown that the combination of these three techniques results in congruent but also synergetic data.

Comparison of gene expression in hepatocellular carcinoma, liver development, and liver regeneration

Proliferation of liver cells can be observed in hepatocarcinogenesis, at different stages of liver development, and during liver regeneration after an injury. Does it imply that they share similar molecular mechanisms? Here, the transcriptional profiles of hepatocellular carcinoma (HCC), liver development, and liver regeneration were systematically compared as a preliminary attempt to answer this question. From the comparison, we found that advanced HCC mimics early development in terms of deprived normal liver functions and activated cellular proliferation, but advanced HCC and early development differ in expressions of cancer-related genes and their transcriptional controls. HCC and liver regeneration demonstrate different expression patterns as a whole, but regeneration is similar to dysplasia (pre-stage of HCC) in terms of their proximity to the normal state. In summary, of these three important processes, the carcinogenic progress carries the highest variance in expression; HCC pre-stage shares some resemblance with liver regeneration; and advanced HCC stage displays similarity with early development.

Characterization of the Human Cervical Mucous Proteome

Introduction

Cervical cancer is among the most common cancers in women worldwide. Discovery of biomarkers for the early detection of cervical cancer would improve current screening practices and reduce the burden of disease.

Objective

In this study, we report characterization of the human cervical mucous proteome as the first step towards protein biomarker discovery.

Methods

The protein composition was characterized using one- and two-dimensional gel electrophoresis, and liquid chromatography coupled with mass spectrometry. We chose to use this combination of traditional biochemical techniques and proteomics to allow a more comprehensive analysis.

Results and Conclusion

A total of 107 unique proteins were identified, with plasma proteins being most abundant. These proteins represented the major functional categories of metabolism, immune response, and cellular transport. Removal of high molecular weight abundant proteins by immunoaffinity purification did not significantly increase the number of protein spots resolved. We also analyzed phosphorylated and glycosylated proteins by fluorescent post-staining procedures. The profiling of cervical mucous proteins and their post-translational modifications can be used to further our understanding of the cervical mucous proteome.

Identification of S100A8-correlated genes for prediction of disease progression in non-muscle invasive bladder cancer

Background

S100 calcium binding protein A8 (S100A8) has been implicated as a prognostic indicator in several types of cancer. However, previous studies are limited in their ability to predict the clinical behavior of the cancer. Here, we sought to identify a molecular signature based on S100A8 expression and to assess its usefulness as a prognostic indicator of disease progression in non-muscle invasive bladder cancer (NMIBC).

Methods

We used 103 primary NMIBC specimens for microarray gene expression profiling. The median follow-up period for all patients was 57.6 months (range: 3.2 to 137.0 months). Various statistical methods, including the leave-one-out cross validation method, were applied to identify a gene expression signature able to predict the likelihood of progression. The prognostic value of the gene expression signature was validated in an independent cohort (n = 302).

Results

Kaplan-Meier estimates revealed significant differences in disease progression associated with the expression signature of S100A8-correlated genes (log-rank test, P < 0.001). Multivariate Cox regression analysis revealed that the expression signature of S100A8-correlated genes was a strong predictor of disease progression (hazard ratio = 15.225, 95% confidence interval = 1.746 to 133.52, P = 0.014). We validated our results in an independent cohort and confirmed that this signature produced consistent prediction patterns. Finally, gene network analyses of the signature revealed that S100A8, IL1B, and S100A9 could be important mediators of the progression of NMIBC.

Conclusions

The prognostic molecular signature defined by S100A8-correlated genes represents a promising diagnostic tool for the identification of NMIBC patients that have a high risk of progression to muscle invasive bladder cancer.

mRNA Expression of S100A8 as a Prognostic Marker for Progression of Non-Muscle-Invasive Bladder Cancer

PURPOSE

S100A8 is a member of the S100 protein family containing 2EF-hand calcium-binding motifs. S100 proteins are involved in the regulation of a number of cellular processes such as cell cycle progression and differentiation. Altered expression of this protein is associated with various diseases and cancers. The present study aimed to evaluate whether S100A8 has prognostic value for non-muscle-invasive bladder cancer (NMIBC).

MATERIALS AND METHODS

A total of 103 primary NMIBC samples obtained by transurethral resection were evaluated. mRNA levels were examined by real-time reverse transcriptase polymerase chain reaction (RT-PCR) analysis. The results were compared with clinico-pathological parameters. The Kaplan-Meier method was applied to plot the curves for progression-free survival. The multivariate Cox regression model was used to identify the independent prognostic factors for progression.

RESULTS

mRNA expression levels of S100A8 were significantly related to the progression of NMIBC. Kaplan-Meier estimates demonstrated significant differences in tumor progression according to the level of S100A8 expression (log-rank test, p<0.001). The multivariate Cox regression model revealed that the S100A8 mRNA expression level (hazard ratio: 12.538; 95% confidence interval: 2.245-70.023, p=0.004) was an independent predictor for disease progression of NMIBC.

CONCLUSIONS

Expression levels of S100A8 might be a useful prognostic marker for disease progression of NMIBC.

Comparative proteomic analysis of cancerous and adjacent normal lung tissues

Lung cancer is the leading cause of cancer-related mortality in industrialized countries. Unfortunately, most lung cancers are found too late for a cure, therefore early detection and treatment is very important. We have applied proteomic analysis by using two-dimensional gel electrophoresis and peptide mass fingerprinting techniques for examination of cancerous and adjacent non-cancerous lung tissues from the same patient. The aim of the study was to find proteins, which could be used as biomarkers for diagnosis and monitoring of this disease. Indeed, we found differences in expression of several proteins, related to various cellular activities, such as, chaperoning (e,g. GRP96, GRP78, HSP27), metabolism and oxidation stress (e.g. L-fucose, GST), cytoskeleton (e.g., tubulin beta 2/3, beta actin), cell adhesion (e.g. annexin A5/3), binding proteins (e.g. 14-3-3 theta) and signal transduction. These changes may be important for progression of carcinogenesis; they may be used as the molecular-support for future diagnostic markers.

Nanozeolite-driven approach for enrichment of secretory proteins in human hepatocellular carcinoma cells

Given the importance of secreted proteins as a source for early detection and diagnosis of disease, secreted proteins have been arousing considerable attention. However, the analysis of secreted proteins represents a challenge for current proteomic techniques. One of the difficulties in secretomic study is to concentrate proteins from large volume of growth media, particularly, the low abundant and low molecular weight proteins (molecular weight <30 kDa). Herein, we describe a novel strategy for harvesting secretory proteins. In this approach, proteins secreted from the human hepatocellular carcinoma cell line were enriched by zeolite LTL nanocrystals, followed by 1-D SDS-PAGE for protein fractionation and then by LC-ESI-MS/MS for protein identification. In total, 1474 unique proteins were confidently identified, including 505 low molecular weight proteins, and covered a broad range of pI and molecular weight. Furthermore, this study not only offered an efficient and powerful method for the enrichment of secretory proteins but also allowed in-depth study of secretome of hepatocellular carcinoma cells. The reported work is expected to represent one of the most comprehensive secretomic analyses so far.

S100A8/A9: a Janus-faced molecule in cancer therapy and tumorgenesis

Correlations exist between the abundance of S100 proteins and disease pathologies. Indeed, this is evidenced by the heterodimeric S100 protein complex S100A8/A9 which has been shown to be involved in inflammatory and neoplastic disorders. However, S100A8/A9 appears as a Janus-faced molecule in this context. On the one hand, it is a powerful apoptotic agent produced by immune cells, making it a very fascinating tool in the battle against cancer. It spears the risk to induce auto-immune response and may serve as a lead compound for cancer-selective therapeutics. In contrast, S100A8/A9 expression in cancer cells has also been associated with tumor development, cancer invasion or metastasis. Clearly, there is a dichotomy and future investigations into the role of S100A8/A9 in cancer biology need to consider both sides of the same coin.

Endogenous damage-associated molecular pattern molecules at the crossroads of inflammation and cancer

Inflammatory mediators play important roles in the development and progression of cancer. Cellular stress, damage, inflammation, and necrotic cell death cause release of endogenous damage-associated molecular pattern (DAMP) molecules or alarmins, which alert the host of danger by triggering immune responses and activating repair mechanisms through their interaction with pattern recognition receptors. Recent studies show that abnormal persistence of these molecules in chronic inflammation and in tumor microenvironments underlies carcinogenesis and tumor progression, indicating that DAMP molecules and their receptors could provide novel targets for therapy. This review focuses on the role of DAMP molecules high-mobility group box 1 and S100 proteins in inflammation, tumor growth, and early metastatic events.

A novel p53 target gene, S100A9, induces p53-dependent cellular apoptosis and mediates the p53 apoptosis pathway

S100A9 (S100 calcium-binding protein A9) is a calcium-binding protein of the S100 family, and its differential expression has been associated with acute and chronic inflammation and several human cancers. Our previous work showed that S100A9 was severely down-regulated in human ESCC (oesophageal squamous cell carcinoma). To further investigate the transcriptional regulation of S100A9, we analysed the S100A9 promoter region and found several putative p53BS (p53-binding sites). Luciferase reporter assays showed that constructs carrying the p53BS exhibited enhanced luciferase activity in response to wild-type p53 activation. Further study demonstrated that S100A9 mRNA and protein expression could be positively regulated in a p53-dependent manner and p53 could bind to p53BS on the S100A9 promoter. Overexpression of S100A9 could induce cellular apoptosis, and this was partly p53-dependent. Knockdown of S100A9 impaired the apoptosis induced by p53. Thus we conclude that a gene down-regulated in ESCC, S100A9, is a novel p53 transcriptional target, induces cellular apoptosis in a partly p53-dependent manner and mediates the p53 apoptosis pathway.

Identification of S100A8 and S100A9 as serological markers for colorectal cancer

In search of novel serological protein biomarkers for human colorectal cancer (CRC), we analyzed CRC tissues using two-dimensional difference in-gel electrophoresis (2D-DIGE) on a narrow range IPG strip (pH 5.5-6.7). By comparing tumor tissues with matched normal tissues in a pairwise manner (n = 6), we identified 34 up-regulated and 17 down-regulated spots with intensity changes greater than 2-fold (Student's t-test, p < 0.05). Expression of both mRNA and protein levels of four proteins, adenosylhomocysteinase, Nm23-H1, S100A8 and S100A9, in CRC tissues was further evaluated by semiquantitative RT-PCR and Western blot analysis. The results revealed that all four proteins were elevated in the tumor tissues. We also confirmed, by immunohistochemistry, that adenosylhomocysteinase and Nm23-H1 were overexpressed in tumor cell cytoplasm and that S100A8 and S100A9 proteins were strongly expressed in tumor infiltrating immune cells. Western blot analysis with fractionated plasma samples showed that S100A8 and S100A9 were significantly increased in the plasma of CRC patients (n = 77) and colorectal adenoma patients (n = 11), compared to healthy controls (n = 21). The area under a receiver operating characteristic (ROC) curve was 0.91 for S100A8 and 0.89 for S100A9, which was superior to the established tumor marker carcinoembryonic antigen with 0.78 for the area under the ROC curve. Some patients with inflammatory diseases such as pancreatitis also showed elevated levels of the proteins. Importantly, in comparison to the control group, both proteins showed a remarkable change at the early stage of cancer. Therefore, we suggest S100A8 and S100A9 as candidates for serological biomarkers in combination with other serum markers that aid CRC diagnosis.