Calcyclin (S100A6) regulates pulmonary fibroblast proliferation, morphology, and cytoskeletal organization in vitro

Characterization of primary human leptomeningeal cells in 2D culture

Maintaining the integrity of brain barriers is critical for a healthy central nervous system. While extensive research has focused on the blood-brain barrier (BBB) of the brain vasculature and blood-cerebrospinal fluid barrier (BCSFB) of the choroid plexus, the barriers formed by the meninges have not received as much attention. These membranes create a barrier between the brain and cerebrospinal fluid (CSF), as well as between CSF and blood. Recent studies have revealed that this barrier has been implicated in the development of neurological and immunological disorders. In order to gain a deeper comprehension of the functioning and significance of the meningeal barriers, sophisticated models of these barriers, need to be created. The aim of this paper is to investigate the characteristics of commercially available primary leptomeningeal cells (LMCs) that form the meningeal barriers, in a cultured environment, including their morphology, proteomics, and barrier properties, and to determine whether passaging of these cells affects their behaviour in comparison to their in vivo state. The results indicate that higher passage numbers significantly alter the morphology and protein localisation and expression of the LMCs. Furthermore, the primary cell culture co-stained for S100A6 and E-cadherin suggesting it is a co-culture of both pial and arachnoid cells. Additionally, cultured LMCs showed an increase in vimentin and cytokeratin expression and a lack of junctional proteins localisation on the cell membrane, which could suggest loss of epithelial properties due to culture, preventing barrier formation. This study shows that the LMCs may be a co-culture of pial and arachnoid cells, that the optimal LMC passage range is between passages two and five for experimentation and that the primary human LMCs form a weak barrier when in culture.

Interplay of Ca2+ and K+ signals in cell physiology and cancer

The cytoplasmic Ca2+ concentration and the activity of K+ channels on the plasma membrane regulate cellular processes ranging from mitosis to oriented migration. The interplay between Ca2+ and K+ signals is intricate, and different cell types rely on peculiar cellular mechanisms. Derangement of these mechanisms accompanies the neoplastic progression. The calcium signals modulated by voltage-gated (KV) and calcium-dependent (KCa) K+ channel activity regulate progression of the cell division cycle, the release of growth factors, apoptosis, cell motility and migration. Moreover, KV channels regulate the cell response to the local microenvironment by assembling with cell adhesion and growth factor receptors. This chapter summarizes the pathophysiological roles of Ca2+ and K+ fluxes in normal and cancer cells, by concentrating on several biological systems in which these functions have been studied in depth, such as early embryos, mammalian cell lines, T lymphocytes, gliomas and colorectal cancer cells. A full understanding of the underlying mechanisms will offer a comprehensive view of the ion channel implication in cancer biology and suggest potential pharmacological targets for novel therapeutic approaches in oncology.

S100A6: molecular function and biomarker role

S100A6 (also called calcyclin) is a Ca2+-binding protein that belongs to the S100 protein family. S100A6 has many functions related to the cytoskeleton, cell stress, proliferation, and differentiation. S100A6 also has many interacting proteins that are distributed in the cytoplasm, nucleus, cell membrane, and outside the cell. Almost all these proteins interact with S100A6 in a Ca2+-dependent manner, and some also have specific motifs responsible for binding to S100A6. The expression of S100A6 is regulated by several transcription factors (such as c-Myc, P53, NF-κB, USF, Nrf2, etc.). The expression level depends on the specific cell type and the transcription factors activated in specific physical and chemical environments, and is also related to histone acetylation, DNA methylation, and other epigenetic modifications. The differential expression of S100A6 in various diseases, and at different stages of those diseases, makes it a good biomarker for differential diagnosis and prognosis evaluation, as well as a potential therapeutic target. In this review, we mainly focus on the S100A6 ligand and its transcriptional regulation, molecular function (cytoskeleton, cell stress, cell differentiation), and role as a biomarker in human disease and stem cells.

Cancer and Alzheimer's Inverse Correlation: an Immunogenetic Analysis

Numerous studies have demonstrated an inverse link between cancer and Alzheimer's disease (AD), with data suggesting that people with Alzheimer's have a decreased risk of cancer and vice versa. Although other studies have investigated mechanisms to explain this relationship, the connection between these two diseases remains largely unexplained. Processes seen in cancer, such as decreased apoptosis and increased cell proliferation, seem to be reversed in AD. Given the need for effective therapeutic strategies for AD, comparisons with cancer could yield valuable insights into the disease process and perhaps result in new treatments. Here, through a review of existing literature, we compared the expressions of genes involved in cell proliferation and apoptosis to establish a genetic basis for the reciprocal association between AD and cancer. We discuss an array of genes involved in the aforementioned processes, their relevance to both diseases, and how changes in those genes produce varying effects in either disease.

S100A6 Protein-Expression and Function in Norm and Pathology

S100A6, also known as calcyclin, is a calcium-binding protein belonging to the S100 protein family. It was first identified and purified more than 30 years ago. Initial structural studies, focused mostly on the mode and affinity of Ca²⁺ binding and resolution of the resultant conformational changes, were soon complemented by research on its expression, localization and identification of binding partners. With time, the use of biophysical methods helped to resolve the structure and versatility of S100A6 complexes with some of its ligands. Meanwhile, it became clear that S100A6 expression was altered in various pathological states and correlated with the stage/progression of many diseases, including cancers, indicative of its important, and possibly causative, role in some of these diseases. This, in turn, prompted researchers to look for the mechanism of S100A6 action and to identify the intermediary signaling pathways and effectors. After all these years, our knowledge on various aspects of S100A6 biology is robust but still incomplete. The list of S100A6 ligands is growing all the time, as is our understanding of the physiological importance of these interactions. The present review summarizes available data concerning S100A6 expression/localization, interaction with intracellular and extracellular targets, involvement in Ca²⁺-dependent cellular processes and association with various pathologies.

Astragaloside IV promotes pharmacological effect of Descurainia sophia seeds on isoproterenol-induced cardiomyopathy in rats by synergistically modulating the myosin motor

Descurainia sophia seeds (DS), Astragalus mongholicus (AM), and their formulas are widely used to treat heart failure caused by various cardiac diseases in traditional Chinese medicine practice. However, the molecular mechanism of action of DS and AM has not been completely understood. Herein, we first used mass spectrometry coupled to UPLC to characterize the chemical components of DS and AM decoctions, then applied MS-based quantitative proteomic analysis to profile protein expression in the heart of rats with isoproterenol-induced cardiomyopathy (ISO-iCM) before and after treated with DS alone or combined with AM, astragaloside IV (AS4), calycosin-7-glucoside (C7G), and Astragalus polysaccharides (APS) from AM. We demonstrated for the first time that DS decoction alone could reverse the most of differentially expressed proteins in the heart of the rats with ISO-iCM, including the commonly recognized biomarkers natriuretic peptides (NPPA) of cardiomyopathy and sarcomeric myosin light chain 4 (MYL4), relieving ISO-iCM in rats, but AM did not pronouncedly improve the pharmacological efficiency of DS. Significantly, we revealed that AS4 remarkably promoted the pharmacological potency of DS by complementarily reversing myosin motor MYH6/7, and further downregulating NPPA and MYL4. In contrast, APS reduced the efficiency of DS due to upregulating NPPA and MYL4. These findings not only provide novel insights to better understanding in the combination principle of traditional Chinese medicine but also highlight the power of mass spectrometric proteomics strategy combined with conventional pathological approaches for the traditional medicine research.

Mitosis, Focus on Calcium

The transformation of a single fertilised egg into an adult human consisting of tens of trillions of highly diverse cell types is a marvel of biology. The expansion is largely achieved by cell duplication through the process of mitosis. Mitosis is essential for normal growth, development, and tissue repair and is one of the most tightly regulated biological processes studied. This regulation is designed to ensure accurate segregation of chromosomes into each new daughter cell since errors in this process can lead to genetic imbalances, aneuploidy, that can lead to diseases including cancer. Understanding how mitosis operates and the molecular mechanisms that ensure its fidelity are therefore not only of significant intellectual value but provide unique insights into disease pathology. The purpose of this review is to revisit historical evidence that mitosis can be influenced by the ubiquitous second messenger calcium and to discuss this in the context of new findings revealing exciting new information about its role in cell division.

Toxoplasma gondii SAG1 targeting host cell S100A6 for parasite invasion and host immunity

Toxoplasma gondii surface antigen 1 (TgSAG1) is a surface protein of tachyzoites, which plays a crucial role in toxoplasma gondii infection and host cell immune regulation. However, how TgSAG1 regulates these processes remains elucidated. We utilized the biotin ligase -TurboID fusion with TgSAG1 to identify the host proteins interacting with TgSAG1, and identified that S100A6 was co-localized with TgSAG1 when T. gondii attached to the host cell. S100A6, either knocking down or blocking its functional epitopes resulted in inhibited parasites invasion. Meanwhile, S100A6 overexpression in host cells promoted T. gondii infection. We further verified that TgSAG1 could inhibit the interaction of host cell vimentin with S100A6 for cytoskeleton organization during T. gondii invasion. As an immunogen, TgSAG1 could promote the secretion of tumor necrosis factor alpha (TNF-α) through S100A6-Vimentin/PKCθ-NF-κB signaling pathway. In summary, our findings revealed a mechanism for how TgSAG1 functioned in parasitic invasion and host immune regulation.

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TgSAG1 interacts with host protein S100A6 then regulates T. gondii infection

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TgSAG1 could regulate binding vimentin with S100A6 during T. gondii infection

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TgSAG1 regulate TNFα secretion through S100A6-vimentin/PKCθ-NF-κB signaling pathway

Ca2+-dependent binding of S100A6 to cofilin-1 regulates actin filament polymerization-depolymerization dynamics

S100A6 is a Ca²⁺-binding protein belonging to the S100 family. Many reports indicate that S100A6 is involved in actin filament organization, however the mechanism of S100A6 action in this process is not fully understood. By screening S100A6 binding partners in NIH3T3 mouse fibroblasts, we have found that S100A6 binds cofilin-1, a protein required for the dynamics of actin polymerization and depolymerization. By applying various biochemical and cell biology assays, we have shown that S100A6 bound to cofilin-1 in a Ca²⁺-dependent manner and increased cofilin-1 affinity for F-actin. Microscopic analysis indicated that S100A6 significantly decreased severing of the actin filaments induced by cofilin-1. Moreover, in the presence of cofilin-1, S100A6 stabilized the filaments by inhibiting their depolymerization. When S100A6 was present at sub-stoichiometric concentrations in relation to actin, polymerization of G-actin accelerated by cofilin-1 was increased. At higher S100A6:actin ratios the polymerization rate was decreased. Altogether, these results show that S100A6 regulates actin filament dynamics by controlling activity of cofilin-1 and suggest that this regulation is Ca²⁺ -dependent.

Alveolar cells under mechanical stressed niche: critical contributors to pulmonary fibrosis

Pulmonary fibrosis arises from the repeated epithelial mild injuries and insufficient repair lead to over activation of fibroblasts and excessive deposition of extracellular matrix, which result in a mechanical stretched niche. However, increasing mechanical stress likely exists before the establishment of fibrosis since early micro injuries increase local vascular permeability and prompt cytoskeletal remodeling which alter cellular mechanical forces. It is noteworthy that COVID-19 patients with severe hypoxemia will receive mechanical ventilation as supportive treatment and subsequent pathology studies indicate lung fibrosis pattern. At advanced stages, mechanical stress originates mainly from the stiff matrix since boundaries between stiff and compliant parts of the tissue could generate mechanical stress. Therefore, mechanical stress has a significant role in the whole development process of pulmonary fibrosis. The alveoli are covered by abundant capillaries and function as the main gas exchange unit. Constantly subject to variety of damages, the alveolar epithelium injuries were recently recognized to play a vital role in the onset and development of idiopathic pulmonary fibrosis. In this review, we summarize the literature regarding the effects of mechanical stress on the fundamental cells constituting the alveoli in the process of pulmonary fibrosis, particularly on epithelial cells, capillary endothelial cells, fibroblasts, mast cells, macrophages and stem cells. Finally, we briefly review this issue from a more comprehensive perspective: the metabolic and epigenetic regulation.

Binding of S100A6 to actin and the actin-tropomyosin complex

S100A6 is a low molecular weight Ca²⁺-binding protein belonging to the S100 family. Many reports indicate that in the cell S100A6 has an influence on the organization of actin filaments, but so far no direct interaction between S100A6 and actin has been shown. In the present study we investigated binding of S100A6 to actin and the actin-tropomyosin complex. The analyses were performed on G- and F-actin and two tropomyosin isoforms-Tpm1.6 and Tpm1.8. Using purified proteins and a variety of biochemical approaches we have shown that, in a Ca²⁺-bound form, S100A6 directly interacts with G- and F-actin and with tropomyosin, preferentially with isoform Tpm1.8. S100A6 and tropomyosin bind to the same population of filaments and the presence of tropomyosin on the microfilament facilitates the binding of S100A6. By applying proximity ligation assay we have found that in NIH3T3 fibroblasts S100A6 forms complexes both with actin and with tropomyosin. These results indicate that S100A6, through direct interactions with actin and tropomyosin, might regulate the organization and functional properties of microfilaments.

Beta-caryophyllene enhances wound healing through multiple routes

Beta-caryophyllene is an odoriferous bicyclic sesquiterpene found in various herbs and spices. Recently, it was found that beta-caryophyllene is a ligand of the cannabinoid receptor 2 (CB2). Activation of CB2 will decrease pain, a major signal for inflammatory responses. We hypothesized that beta-caryophyllene can affect wound healing by decreasing inflammation. Here we show that cutaneous wounds of mice treated with beta-caryophyllene had enhanced re-epithelialization. The treated tissue showed increased cell proliferation and cells treated with beta-caryophyllene showed enhanced cell migration, suggesting that the higher re-epithelialization is due to enhanced cell proliferation and cell migration. The treated tissues also had up-regulated gene expression for hair follicle bulge stem cells. Olfactory receptors were not involved in the enhanced wound healing. Transient Receptor Potential channel genes were up-regulated in the injured skin exposed to beta-caryophyllene. Interestingly, there were sex differences in the impact of beta- caryophyllene as only the injured skin of female mice had enhanced re-epithelialization after exposure to beta-caryophyllene. Our study suggests that chemical compounds included in essential oils have the capability to improve wound healing, an effect generated by synergetic impacts of multiple pathways.

Exosomes Derived from Human Primary and Metastatic Colorectal Cancer Cells Contribute to Functional Heterogeneity of Activated Fibroblasts by Reprogramming Their Proteome

Cancer-associated fibroblasts (CAFs) are a heterogeneous population of activated fibroblasts that constitute a dominant cellular component of the tumor microenvironment (TME) performing distinct functions. Here, the role of tumor-derived exosomes (Exos) in activating quiescent fibroblasts into distinct functional subtypes is investigated. Proteomic profiling and functional dissection reveal that early- (SW480) and late-stage (SW620) colorectal cancer (CRC) cell-derived Exos both activated normal quiescent fibroblasts (α-SMA^- , CAV⁺ , FAP⁺ , VIM⁺ ) into CAF-like fibroblasts (α-SMA⁺ , CAV^- , FAP⁺ , VIM⁺ ). Fibroblasts activated by early-stage cancer-exosomes (SW480-Exos) are highly pro-proliferative and pro-angiogenic and display elevated expression of pro-angiogenic (IL8, RAB10, NDRG1) and pro-proliferative (SA1008, FFPS) proteins. In contrast, fibroblasts activated by late-stage cancer-exosomes (SW620-Exos) display a striking ability to invade through extracellular matrix through upregulation of pro-invasive regulators of membrane protrusion (PDLIM1, MYO1B) and matrix-remodeling proteins (MMP11, EMMPRIN, ADAM10). Conserved features of Exos-mediated fibroblast activation include enhanced ECM secretion (COL1A1, Tenascin-C/X), oncogenic transformation, and metabolic reprogramming (downregulation of CAV-1, upregulation of glycogen metabolism (GAA), amino acid biosynthesis (SHMT2, IDH2) and membrane transporters of glucose (GLUT1), lactate (MCT4), and amino acids (SLC1A5/3A5)). This study highlights the role of primary and metastatic CRC tumor-derived Exos in generating phenotypically and functionally distinct subsets of CAFs that may facilitate tumor progression.

Deficiency of the mitochondrial sulfide regulator ETHE1 disturbs cell growth, glutathione level and causes proteome alterations outside mitochondria

The mitochondrial enzyme ETHE1 is a persulfide dioxygenase essential for cellular sulfide detoxification, and its deficiency causes the severe and complex inherited metabolic disorder ethylmalonic encephalopathy (EE). In spite of well-described clinical symptoms of the disease, detailed cellular and molecular characterization is still ambiguous. Cellular redox regulation has been described to be influenced in ETHE1 deficient cells, and to clarify this further we applied image cytometry and detected decreased levels of reduced glutathione (GSH) in cultivated EE patient fibroblast cells. Cell growth initiation of the EE patient cells was impaired, whereas cell cycle regulation was not. Furthermore, Seahorse metabolic analyzes revealed decreased extracellular acidification, i. e. decreased lactate formation from glycolysis, in the EE patient cells. TMT-based large-scale proteomics was subsequently performed to broadly elucidate cellular consequences of the ETHE1 deficiency. More than 130 proteins were differentially regulated, of which the majority were non-mitochondrial. The proteomics data revealed a link between ETHE1-deficiency and down-regulation of several ribosomal proteins and LIM domain proteins important for cellular maintenance, and up-regulation of cell surface glycoproteins. Furthermore, several proteins of endoplasmic reticulum (ER) were perturbed including proteins influencing disulfide bond formation (e.g. protein disulfide isomerases and peroxiredoxin 4) and calcium-regulated proteins. The results indicate that decreased level of reduced GSH and alterations in proteins of ribosomes, ER and of cell adhesion lie behind the disrupted cell growth of the EE patient cells.

S100A6 promotes proliferation of intrahepatic cholangiocarcinoma cells via the activation of the p38/MAPK pathway

Aim: We explored the expression of S100A6 and its role in intrahepatic cholangiocarcinoma (ICC). Methods: The expression of S100A6 in ICC samples was detected by immunohistochemistry. In vitro experiments, we silenced and overexpressed S100A6 to investigate its role in cell functions. Results: The expression of S100A6 was markedly increased in ICC tissues and cell lines. S100A6 overexpression was an independent risk factor for patients’ survival. Silencing S100A6 resulted in a suppression of proliferation and p38/MAPK activity, while overexpressing S100A6 caused a promotion of proliferation and p38/MAPK. Discussion: S100A6 participated in the proliferation of ICC cells and correlated with a more aggressive behavior of ICC. Conclusion: S100A6 may serve as a novel prognostic marker and a potential therapeutic target for ICC patients.

S100A6 protein: functional roles

S100A6 protein belongs to the A group of the S100 protein family of Ca2+-binding proteins. It is expressed in a limited number of cell types in adult normal tissues and in several tumor cell types. As an intracellular protein, S100A6 has been implicated in the regulation of several cellular functions, such as proliferation, apoptosis, the cytoskeleton dynamics, and the cellular response to different stress factors. S100A6 can be secreted/released by certain cell types which points to extracellular effects of the protein. RAGE (receptor for advanced glycation endproducts) and integrin β1 transduce some extracellular S100A6's effects. Dosage of serum S100A6 might aid in diagnosis in oncology.

Molecular patterns of diffuse and nodular parathyroid hyperplasia in long-term hemodialysis

Secondary hyperparathyroidism is a well-known complication of end-stage renal disease (ESRD). Both nodular and diffuse parathyroid hyperplasia occur in ESRD patients. However, their distinct molecular mechanisms remain poorly understood. Parathyroid tissue obtained from ESRD patients who had undergone parathyroidectomy was used for Illumina transcriptome screening and subsequently for discriminatory gene analysis, pathway mapping, and gene annotation enrichment analysis. Results were further validated using quantitative RT-PCR on the independent larger cohort. Microarray screening proved homogeneity of gene transcripts in hemodialysis patients compared with the transplant cohort and primary hyperparathyroidism; therefore, further experiments were performed in hemodialysis patients only. Enrichment analysis conducted on 485 differentially expressed genes between nodular and diffuse parathyroid hyperplasia revealed highly significant differences in Gene Ontology terms and the Kyoto Encyclopedia of Genes and Genomes database in ribosome structure (P = 3.70 × 10^-18). Next, quantitative RT-PCR validation of the top differently expressed genes from microarray analysis proved higher expression of RAN guanine nucleotide release factor (RANGRF; P < 0.001), calcyclin-binding protein (CACYBP; P < 0.05), and exocyst complex component 8 (EXOC8; P < 0.05) and lower expression of peptidylprolyl cis/trans-isomerase and NIMA-interacting 1 (PIN1; P < 0.01) mRNA in nodular hyperplasia. Multivariate analysis revealed higher RANGRF and lower PIN1 expression along with parathyroid weight to be associated with nodular hyperplasia. In conclusion, our study suggests the RANGRF transcript, which controls RNA metabolism, to be likely involved in pathways associated with the switch to nodular parathyroid growth. This transcript, along with PIN1 transcript, which influences parathyroid hormone secretion, may represent new therapeutical targets to cure secondary hyperparathyroidism.

S100A6 promotes cell proliferation in human nasopharyngeal carcinoma via the p38/MAPK signaling pathway

An elevated level of S100A6 is associated with poor outcomes of many tumor types, but, how S100A6 contributes to nasopharyngeal carcinoma (NPC) progression remains unknown. Here, we investigated the expression and prognostic significance of S100A6 in NPC and explored the molecular mechanisms under-lying the role of S100A6 in NPC development. The results showed that S100A6 was markedly up-regulated in NPC tissues and cell lines compared to paired peritumoral normal tissues and a normal nasopharyngeal epithelial cell line, respectively. In tissues from 92 NPC patients, high S100A6 expression was associated with advanced N stage, locoregional failure and disease progression and was predictive of poor locoregional recurrence-free survival (LRRFS, P = 0.001) and progression-free survival (PFS, P = 0.001). Multivariate analysis showed that S100A6 is an independent prognostic factor for LRRFS and PFS. Silencing S100A6 using siRNA or shRNA significantly suppressed NPC cell proliferation, colony formation and p38/mitogen-activated protein kinase (MAPK) activity in vitro and inhibited tumor growth in a xenograft mouse model of NPC. In contrast, overexpressing S100A6 via plasmid transfection resulted in increased NPC cell proliferation and p38/MAPK activation. S100A6-induced proliferation was abolished by a p38 inhibitor. In summary, S100A6 may be a new prognostic marker of NPC and may promote NPC development via the activation of p38/MAPK signaling pathways. These findings suggest S100A6/p38/MAPK signaling as a potential therapeutic target for NPC. © 2016 Wiley Periodicals, Inc.

Bio-Adaption between Magnesium Alloy Stent and the Blood Vessel: A Review

Biodegradable magnesium (Mg) alloy stents are the most promising next generation of bio-absorbable stents. In this article, we summarized the progresses on the in vitro studies, animal testing and clinical trials of biodegradable Mg alloy stents in the past decades. These exciting findings led us to propose the importance of the concept "bio-adaption" between the Mg alloy stent and the local tissue microenvironment after implantation. The healing responses of stented blood vessel can be generally described in three overlapping phases: inflammation, granulation and remodeling. The ideal bio-adaption of the Mg alloy stent, once implanted into the blood vessel, needs to be a reasonable function of the time and the space/dimension. First, a very slow degeneration of mechanical support is expected in the initial four months in order to provide sufficient mechanical support to the injured vessels. Although it is still arguable whether full mechanical support in stented lesions is mandatory during the first four months after implantation, it would certainly be a safety design parameter and a benchmark for regulatory evaluations based on the fact that there is insufficient human in vivo data available, especially the vessel wall mechanical properties during the healing/remodeling phase. Second, once the Mg alloy stent being degraded, the void space will be filled by the regenerated blood vessel tissues. The degradation of the Mg alloy stent should be 100% completed with no residues, and the degradation products (e.g., ions and hydrogen) will be helpful for the tissue reconstruction of the blood vessel. Toward this target, some future research perspectives are also discussed.

Next-generation technologies for spatial proteomics: Integrating ultra-high speed MALDI-TOF and high mass resolution MALDI FTICR imaging mass spectrometry for protein analysis

MALDI imaging mass spectrometry is a powerful analytical tool enabling the visualization of biomolecules in tissue. However, there are unique challenges associated with protein imaging experiments including the need for higher spatial resolution capabilities, improved image acquisition rates, and better molecular specificity. Here we demonstrate the capabilities of ultra-high speed MALDI-TOF and high mass resolution MALDI FTICR IMS platforms as they relate to these challenges. High spatial resolution MALDI-TOF protein images of rat brain tissue and cystic fibrosis lung tissue were acquired at image acquisition rates >25 pixels/s. Structures as small as 50 μm were spatially resolved and proteins associated with host immune response were observed in cystic fibrosis lung tissue. Ultra-high speed MALDI-TOF enables unique applications including megapixel molecular imaging as demonstrated for lipid analysis of cystic fibrosis lung tissue. Additionally, imaging experiments using MALDI FTICR IMS were shown to produce data with high mass accuracy (<5 ppm) and resolving power (∼75 000 at m/z 5000) for proteins up to ∼20 kDa. Analysis of clear cell renal cell carcinoma using MALDI FTICR IMS identified specific proteins localized to healthy tissue regions, within the tumor, and also in areas of increased vascularization around the tumor.

The potential role of CacyBP/SIP in tumorigenesis

Calcyclin-binding protein/Siah-1-interacting protein (CacyBP/SIP) was initially described as a binding partner of S100A6 in the Ehrlich ascites tumor cells and later as a Siah-1-interacting protein. This 30 kDa protein includes three domains and is involved in cell proliferation, differentiation, cytoskeletal rearrangement, and transcriptional regulation via binding to various proteins. Studies have also shown that the CacyBP/SIP is a critical protein in tumorigenesis. But, its promotion or suppression of cancer progression may depend on the cell type. In this review, the biological characteristics and target proteins of CacyBP/SIP have been described. Moreover, the exact role of CacyBP/SIP in various cancers is discussed.

Identification of potential therapeutic targets for papillary thyroid carcinoma by bioinformatics analysis

The aim of the present study was to identify potential therapeutic targets for papillary thyroid carcinoma (PTC) and to investigate the possible mechanism underlying this disease. The gene expression profile, GSE53157, was downloaded from the Gene Expression Omnibus database. Only 10 chips, including 3 specimens of normal thyroid tissues and 7 specimens of well-differentiated thyroid carcinomas, were analyzed in the present study. Differentially-expressed genes (DEGs) between PTC patients and normal individuals were identified. Next, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses of DEGs were performed. Modules in the protein-protein interaction (PPI) network were identified. Significant target genes were selected from the microRNA (miRNA) regulatory network. Furthermore, the integrated network was constructed with the miRNA regulatory and PPI network modules, and key target genes were screened. A total of 668 DEGs were identified. Modules M1, M2 and M3 were identified from the PPI network. From the modules, DEGs of cyclin-dependent kinase inhibitor 1A, S100 calcium binding protein A6 (S100A6), dual specificity phosphatase 5, keratin 19, met proto-oncogene (MET) and lectin galactoside-binding soluble 3 were included in the Malacards database. In the miRNA regulatory and integrated networks, genes of cyclin-dependent kinase inhibitor 1C (CDKN1C), peroxisome proliferator-activated receptor γ, aryl hydrocarbon receptor, basic helix-loop-helix family, member e40 and reticulon 1 were the key target genes. S100A6, MET and CDKN1C may exhibit key roles in the progression and development of PTC, and may be used as specific therapeutic targets in the treatment of PTC. However, further experiments are required to confirm these results.

Calcium Homeostasis and Ionic Mechanisms in Pulmonary Fibroblasts

Fibroblasts are key cellular mediators of many chronic interstitial lung diseases, including idiopathic pulmonary fibrosis, scleroderma, sarcoidosis, drug-induced interstitial lung disease, and interstitial lung disease in connective tissue disease. A great deal of effort has been expended to understand the signaling mechanisms underlying the various cellular functions of fibroblasts. Recently, it has been shown that Ca(2+) oscillations play a central role in the regulation of gene expression in human pulmonary fibroblasts. However, the mechanisms whereby cytosolic [Ca(2+)] are regulated and [Ca(2+)] oscillations transduced are both poorly understood. In this review, we present the general concepts of [Ca(2+)] homeostasis, of ionic mechanisms responsible for various Ca(2+) fluxes, and of regulation of gene expression by [Ca(2+)]. In each case, we then also summarize the original findings that pertain specifically to pulmonary fibroblasts. From these data, we propose an overall signaling cascade by which excitation of the fibroblasts triggers pulsatile release of internally sequestered Ca(2+), which, in turn, activates membrane conductances, including voltage-dependent Ca(2+) influx pathways. Collectively, these events produce recurring Ca(2+) oscillations, the frequency of which is transduced by Ca(2+)-dependent transcription factors, which, in turn, orchestrate a variety of cellular events, including proliferation, synthesis/secretion of extracellular matrix proteins, autoactivation (production of transforming growth factor-β), and transformation into myofibroblasts. That unifying hypothesis, in turn, allows us to highlight several specific cellular targets and therapeutic intervention strategies aimed at controlling unwanted pulmonary fibrosis. The relationships between Ca(2+) signaling events and the unfolded protein response and apoptosis are also explored.

High-level S100A6 promotes metastasis and predicts the outcome of T1-T2 stage in clear cell renal cell carcinoma

S100A6 (calcyclin), functions in cell cycle progression and differentiation, has been reported to promote the tumorigenesis and malignancy of many types of cancers. Clear cell renal cell carcinoma (ccRCC) is the most common subtype of RCC, lacking both promising prognostic markers and effective therapeutic targets. In our previous study, we have found the elevated S100A6 in the ccRCC tumor tissues, and the differentially expressed genes determined by microarray analysis were found to be strongly related to tumor metastasis after S100A6 knockdown and overexpression in the ccRCC cell line 786-O. The mRNA expression of S100A6 detected by RT-PCR in 6 cell lines and 174 tumor tissues, including 58 metastatic ccRCC and 116 clinicopathological features paired non-metastatic ccRCC (1:2), indicated S100A6 was elevated in the metastatic cells and tumor tissues. The protein expression was consistent with mRNA expression. The biological function of S100A6 in promoting metastasis was determined through overexpression and knockdown of S100A6 in the ccRCC cell lines 786-O, caki-1, and ACHN. In the scratch wound migration assay as well as migration and invasion assays, S100A6 knockdown significantly suppressed the migratory and invasive abilities of tumor cells, whereas overexpression enhanced the malignancy. Further research with the follow-up data of 129 ccRCC patients were analyzed by the Cox regression and survival analysis. The expression of S100A6 was up-regulated in metastatic ccRCC cells. In the metastatic tumor tissues, the expression of S100A6 was also higher than in the non-metastatic tissues. High S100A6 expression might be crucial to promote metastasis in ccRCC by enhancing the ability of tumor cells migration and invasion. In addition, the quantitative mRNA expression of S100A6 in the tumor tissues was an independent risk factor and might be used as a prognostic marker for the metastatic risk of the localized T1-T2 stage ccRCC.

Joining S100 proteins and migration: for better or for worse, in sickness and in health

The vast diversity of S100 proteins has demonstrated a multitude of biological correlations with cell growth, cell differentiation and cell survival in numerous physiological and pathological conditions in all cells of the body. This review summarises some of the reported regulatory functions of S100 proteins (namely S100A1, S100A2, S100A4, S100A6, S100A7, S100A8/S100A9, S100A10, S100A11, S100A12, S100B and S100P) on cellular migration and invasion, established in both culture and animal model systems and the possible mechanisms that have been proposed to be responsible. These mechanisms involve intracellular events and components of the cytoskeletal organisation (actin/myosin filaments, intermediate filaments and microtubules) as well as extracellular signalling at different cell surface receptors (RAGE and integrins). Finally, we shall attempt to demonstrate how aberrant expression of the S100 proteins may lead to pathological events and human disorders and furthermore provide a rationale to possibly explain why the expression of some of the S100 proteins (mainly S100A4 and S100P) has led to conflicting results on motility, depending on the cells used.

Increased expression of S100A6 promotes cell proliferation and migration in human hepatocellular carcinoma

High levels of S100A6 have been associated with poor outcome in some types of human cancers, but the role of S100A6 in the molecular pathogenesis of these cancers is largely unknown. This study was performed to explore the expression and functional roles of S100A6 in hepatocellular carcinoma (HCC). The expression level of S100A6 in HCC tumor and corresponding peritumoral tissues were determined by immunohistochemistry analysis. The potential functions of S100A6 in tumorigenesis and metastasis were analyzed by cell proliferation, migration, and invasion assays in human liver cancer cells. Moreover, through expression and purification of S100A6 recombinant protein tagged with cell-penetrating peptide, we analyzed its complex extracellular/intracellular effects in a S100A6-silenced cellular model. As a result, the expression of S100A6 was up-regulated in human HCC compared with adjacent peritumoral tissues. S100A6 silencing inhibited the growth and motility of HCC cells, while intracellular re-expression of S100A6 could rescue the proliferation and migration defects. Intracellular over-expression of S100A6 resulted in down-regulation of E-cadherin expression and promoted nuclear accumulation of β-catenin. Moreover, we found that the enhanced cell proliferation and motility after S100A6 stimulation were dependent on the activation of PI3K/AKT pathway. These results suggest that S100A6 may be involved in promotion and progression of human liver cancer.

KEY MESSAGES

S100A6 is overexpressed in human hepatocellular carcinoma clinical specimens. S100A6 promotes proliferation and migration of human hepatoma cells. Overexpression of S100A6 results in alteration of E-cadherin and β-catenin. The multi-effects of S100A6 may be mediated in part by PI3K/AKT pathway activation.

S100A6 (calcyclin) is a novel marker of neural stem cells and astrocyte precursors in the subgranular zone of the adult mouse hippocampus

S100A6 (calcyclin), an EF-hand calcium binding protein, is considered to play various roles in the brain, for example, cell proliferation and differentiation, calcium homeostasis, and neuronal degeneration. In addition to some limbic nuclei, S100A6 is distributed in the rostral migratory stream, one of the major neurogenic niches of the adult brain. However, the potential involvement of S100A6 in adult neurogenesis remains unclear. In this study, we aimed to elucidate the role of S100A6 in the other major neurogenic niche, the subgranular zone of the dentate gyrus in the adult mouse hippocampus. Immunofluorescent multiple labeling showed that S100A6 was highly expressed in neural stem cells labeled by sex determining region Y-box 2, brain lipid-binding protein protein and glial fibrillary acidic protein. S100A6+ cells often extended a long process typical of radial glial morphology. In addition, S100A6 was found in some S100β+ astrocyte lineage cells. Interestingly, proliferating cell nuclear antigen was detected in a fraction of S100A6+/S100β+ cells. These cells were considered to be lineage-restricted astrocyte precursors maintaining mitotic potential. On the other hand, S100A6 was rarely seen in neural lineage cells labeled by T-box brain protein 2, doublecortin, calretinin and calbindin D28K. Cell fate-tracing experiment using BrdU showed that the majority of newly generated immature astrocytes were immunoreactive for S100A6, while mature astrocytes lacked S100A6 immunoreactivity. Administration of S100 protein inhibitor, trifluoperazine, caused a reduction in production of S100β+ astrocyte lineage cells, but had no impact on neurogenesis. Overall, our data provide the first evidence that S100A6 is a specific marker of neural stem cells and astrocyte precursors, and may be especially important for generation of astrocytes in the adult hippocampus.

Silencing of doublecortin-like (DCL) results in decreased mitochondrial activity and delayed neuroblastoma tumor growth

Doublecortin-like (DCL) is a microtubule-binding protein crucial for neuroblastoma (NB) cell proliferation. We have investigated whether the anti-proliferative effect of DCL knockdown is linked to reduced mitochondrial activity. We found a delay in tumor development after DCL knockdown in vivo in doxycycline-inducible NB tumor xenografts. To understand the mechanisms underlying this tumor growth retardation we performed a series of in vitro experiments in NB cell lines. DCL colocalizes with mitochondria, interacts with the mitochondrial outer membrane protein OMP25/ SYNJ2BP and DCL knockdown results in decreased expression of genes involved in oxidative phosphorylation. Moreover, DCL knockdown decreases cytochrome c oxidase activity and ATP synthesis. We identified the C-terminal Serine/Proline-rich domain and the second microtubule-binding area as crucial DCL domains for the regulation of cytochrome c oxidase activity and ATP synthesis. Furthermore, DCL knockdown causes a significant reduction in the proliferation rate of NB cells under an energetic challenge induced by low glucose availability. Together with our previous studies, our results corroborate DCL as a key player in NB tumor growth in which DCL controls not only mitotic spindle formation and the stabilization of the microtubule cytoskeleton, but also regulates mitochondrial activity and energy availability, which makes DCL a promising molecular target for NB therapy.

The S100A6 calcium-binding protein regulates endothelial cell-cycle progression and senescence

Endothelial cells regulate many aspects of vascular physiology, including vasculogenesis and angiogenesis. The S100 family of calcium-binding proteins regulates many aspects of cell function but their roles in vascular physiology are less well understood. Herein, we investigated the expression and function of S100-related family members in endothelial cells. Analysis of total endothelial mRNAs using a human gene chip array revealed significant gene expression of the S100 calcium-binding protein family members S100A6, S100A10, S100A11 and S100A13. We then examined the expression and functional properties of the major S100 family member, S100A6, in vascular endothelial cells. Comparison of primary and transformed human cells revealed significant differences in S100A6 protein levels in these cells. In primary human endothelial cells, S100A6 was present in both the nucleus and the cytoplasm. To assess the function of endothelial S100A6, we depleted protein levels using RNA interference and this caused increased cell-cycle arrest in the G2/M phase under different conditions. S100A6 depletion caused a decrease in both cyclin-dependent kinase 1 (CDK1) and phospho-CDK1 levels, which are essential for eukaryote cell-cycle progression. S100A6 depletion also decreased expression of CDK1, cyclin A1 (CCNA1) and cyclin B (CCNB1) genes with effects on cell-cycle progression. Depletion of endothelial S100A6 levels also elevated β-galactosidase expression, which is an important hallmark of cellular senescence and exit from the mammalian cell cycle. We thus propose that S100A6 has an important role in regulating endothelial commitment to, and progression through, the cell cycle.

Processes underlying the nutritional programming of embryonic development by iron deficiency in the rat

Poor iron status is a global health issue, affecting two thirds of the world population to some degree. It is a particular problem among pregnant women, in both developed and developing countries. Feeding pregnant rats a diet deficient in iron is associated with both hypertension and reduced nephron endowment in adult male offspring. However, the mechanistic pathway leading from iron deficiency to fetal kidney development remains elusive. This study aimed to establish the underlying processes associated with iron deficiency by assessing gene and protein expression changes in the rat embryo, focussing on the responses occurring at the time of the nutritional insult. Analysis of microarray data showed that iron deficiency in utero resulted in the significant up-regulation of 979 genes and down-regulation of 1545 genes in male rat embryos (d13). Affected processes associated with these genes included the initiation of mitosis, BAD-mediated apoptosis, the assembly of RNA polymerase II preinitiation complexes and WNT signalling. Proteomic analyses highlighted 7 proteins demonstrating significant up-regulation with iron deficiency and the down-regulation of 11 proteins. The main functions of these key proteins included cell proliferation, protein transport and folding, cytoskeletal remodelling and the proteasome complex. In line with our recent work, which identified the perturbation of the proteasome complex as a generalised response to in utero malnutrition, we propose that iron deficiency alone leads to a more specific failure in correct protein folding and transport. Such an imbalance in this delicate quality-control system can lead to cellular dysfunction and apoptosis. Therefore these findings offer an insight into the underlying mechanisms associated with the development of the embryo during conditions of poor iron status, and its health in adult life.

S100 proteins as diagnostic and prognostic markers in colorectal and hepatocellular carcinoma

CONTEXT

Clinical and experimental studies have suggested a link between S100 gene ex-pression and neoplastic disorders, however, the molecular mechanisms of this associa-tion are not well understood. The aim of this review was to conduct a comprehensive literature search in order to understand the possible underlying molecular mechanisms of this association. We also discuss their application as diagnostic and prognostic mark-ers in colorectal and hepatocellular carcinoma.

EVIDENCE ACQUISITIONS

We searched Pubmed (NLM) and Web of Science (ISI Web of Knowledge).

RESULTS

S100 genes display a complex expression pattern in colorectal and hepatocel- lular carcinoma. They are expressed in tumor and/or tumor stroma cells, and they exert both pro- and antitumorigenic actions. In view of this complexity, it becomes clear that S100 proteins might act as both friend and foe. The biological role of the S100 genes is predicted to depend on the relative contributions of the different cell types at specific stages of tumor progression.

CONCLUSIONS

Further research is required in order to uncover the functional role of S100 genes in tumorigenesis. Answers to this issue are needed before we can more fully un-derstand the clinical relevance of S100 protein expression within epithelial tumors, with regard to their potential applicability as biomarkers for diagnosis and therapy decisions.

Changes in the proteomic profile of adipose tissue-derived mesenchymal stem cells during passages

BACKGROUND

Human mesenchymal stem cells (hMSC) have recently raised the attention because of their therapeutic potential in the novel context of regenerative medicine. However, the safety of these new and promising cellular products should be carefully defined before they can be used in the clinical setting, as. The protein expression profile of these cells might reveal potential hazards associated with senescence and tumoral transformation which may occur during culture. Proteomic is a valuable tool for hMSC characterization and identification of possible changes during expansion.

RESULTS

We used Surface Enhanced Laser Desorption/Ionization-Time Of Flight-Mass Spectrometry (SELDI-ToF-MS) to evaluate the presence of stable molecular markers in adipose tissue-derived mesenchymal stem cells (AD-MSC) produced under conditions of good manufacturing practices (GMP). Proteomic patterns of cells prepared were consistent, with 4 up-regulated peaks (mass-to-charge ratio (m/z) 8950, 10087, 10345, and 13058) through subculture steps (P0-P7) with similar trend in three donors. Among the differentially expressed proteins found in the cytoplasmic and nuclear fractions, a cytoplasmic 10.1 kDa protein was upregulated during culture passages and was identified as S100A6 (Calcyclin).

CONCLUSIONS

This study suggests for the first time that common variation could occur in AD-MSC from different donors, with the identification of S100A6, a protein prevalently related to cell proliferation and cell culture condition. These results support the hypothesis of common proteomic changes during MSCs expansion and could give important insight in the knowledge of molecular mechanisms intervening during MSC expansion.

Matrix-assisted laser desorption/ionization mass spectrometry reveals decreased calcylcin expression in small cell lung cancer

To date, most of the proteomic analyses on lung cancer tissue samples have been performed using surgical specimens, which are obtained after a diagnosis is made. To determine if a proteomic signature obtained from bronchoscopic biopsy samples could be found to assist with diagnosis, 50 lung cancer bronchoscopic biopsy samples and 13 adjacent normal lung tissue samples were analyzed using histology-directed, matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS). Lung tissue samples were cryosectioned, and sinapinic acid was robotically deposited on areas of each tissue section enriched in epithelial cells, either tumor or normal. Mass spectra were acquired using a MALDI-time of flight instrument. Small cell lung cancers (SCLCs) demonstrated clearly different protein profiles from normal lung tissue and from non-small cell lung cancers (NSCLCs). Calcyclin (m/z= 10,094.7) was identified to be underexpressed in small cell lung cancers, as compared with non-small cell lung cancers and normal lung tissue. An immunohistochemistry study using 152 NSCLCs and 21 SCLCs confirmed significantly reduced calcyclin stain in SCLCs. Thus, protein profiles obtained from bronchoscopic biopsy samples via MALDI MS distinguish cancerous epithelium from normal lung tissue and between NSCLCs and SCLCs.

Immunohistochemical Characterization of S100A6 in the Murine Ovary

S100 proteins comprise a large family of Ca(2+)-binding proteins and exhibit a variety of intra- and extracellular functions. Despite our growing knowledge about the biology of S100 proteins in some tissues such as brain and smooth muscle, little is known about S100 proteins in the normal mammalian reproductive tissue. In the present study, we investigated the distribution pattern of S100A6 (alternatively named calcyclin) in the murine ovary by immunohistochemical study using specific antibody. S100A6 was localized substantially in the cytoplasm of luteal cells, with concomitant expression of S100A11, another S100 protein, but not in the other type of cells such as oocytes, follicle epithelial cells (granulosa cells), and cells of stroma including theca interna cells in the murine ovary. S100A6-immunoreactive corpora lutea (CLs) were divided into two types: homogeneously and heterogeneously stained CLs, and possibly they may represent differentiating and mature CL, respectively. Our regression analysis revealed that expression level of S100A6 positively correlated with that of cytochrome P450 11A, a steroidogenic enzyme in the heterogeously stained CL. These results suggested that S100A6 may contribute to differentiation of steroidogenic activity of luteal cells in a synergistic manner with S100A11 by facilitating some shared functions.

Transcription analysis on response of porcine alveolar macrophages to Haemophilus parasuis

Background

Haemophilus parasuis (H. parasuis) is the etiological agent of Glässer's disease in pigs. Currently, the molecular basis of this infection is largely unknown. The innate immune response is the first line of defense against the infectious disease. Systematical analysis on host innate immune response to the infection is important for understanding the pathogenesis of the infectious microorganisms.

Results

A total of 428 differentially expressed (DE) genes were identified in the porcine alveolar macrophages (PAMs) 6 days after H. parasuis infection. These genes were principally related to inflammatory response, immune response, microtubule polymerization, regulation of transcript and signal transduction. Through the pathway analysis, the significant pathways mainly concerned with cell adhesion molecules, cytokine-cytokine receptor interaction, complement and coagulation cascades, toll-like receptor signaling pathway, MAPK signaling pathway, suggesting that the host took different strategies to activate immune and inflammatory response upon H. parasuis infection. The global interactions network and two subnetworks of the proteins encoded by DE genes were analyzed by using STRING. Further immunostimulation analysis indicated that mRNA levels of S100 calcium-binding protein A4 (S100A4) and S100 calcium-binding protein A6 (S100A6) in porcine PK-15 cells increased within 48 h and were sustained after administration of lipopolysaccharide (LPS) and Poly (I:C) respectively. The s100a4 and s100a6 genes were found to be up-regulated significantly in lungs, spleen and lymph nodes in H. parasuis infected pigs. We firstly cloned and sequenced the porcine coronin1a gene. Phylogenetic analysis showed that poCORONIN 1A belonged to the group containing the Bos taurus sequence. Structural analysis indicated that the poCORONIN 1A contained putative domains of Trp-Asp (WD) repeats signature, Trp-Asp (WD) repeats profile and Trp-Asp (WD) repeats circular profile at the N-terminus.

Conclusions

Our present study is the first one focusing on the response of porcine alveolar macrophages to H. parasuis. Our data demonstrate a series of genes are activated upon H. parasuis infection. The observed gene expression profile could help screening the potential host agents for reducing the prevalence of H. parasuis and further understanding the molecular pathogenesis associated with H. parasuis infection in pigs.

S100-A10, thioredoxin, and S100-A6 as biomarkers of papillary thyroid carcinoma with lymph node metastasis identified by MALDI imaging

In papillary thyroid carcinoma (PTC), metastasis is a feature of an aggressive tumor phenotype. To identify protein biomarkers that distinguish patients with an aggressive tumor behavior, proteomic signatures in metastatic and non-metastatic tumors were investigated comparatively. In particular, matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) was used to analyze primary tumor samples. We investigated a tumor cohort of PTC (n = 118) that were matched for age, tumor stage, and gender. Proteomic screening by MALDI-IMS was performed for a discovery set (n = 29). Proteins related to the discriminating mass peaks were identified by 1D-gel electrophoresis followed by mass spectrometry. The candidate proteins were subsequently validated by immunohistochemistry (IHC) using a tissue microarray for an independent PTC validation set (n = 89). In this study, we found 36 mass-to-charge-ratio (m/z) species that specifically distinguished metastatic from non-metastatic tumors, among which m/z 11,608 was identified as thioredoxin, m/z 11,184 as S100-A10, and m/z 10,094 as S100-A6. Furthermore, using IHC on the validation set, we showed that the overexpression of these three proteins was highly associated with lymph node metastasis in PTC (p < 0.005). For functional analysis of the metastasis-specific proteins, we performed an Ingenuity Pathway Analysis and discovered a strong relationship of all candidates with the TGF-β-dependent EMT pathway. Our results demonstrated the potential application of the MALDI-IMS proteomic approach in identifying protein markers of metastasis in PTC. The novel protein markers identified in this study may be used for risk stratification regarding metastatic potential in PTC.

Specific expression of osteopontin and S100A6 in hepatocellular carcinoma

BACKGROUND

Our aim was to identify differential expression of genes in hepatocellular carcinoma (HCC) with the ultimate goal of discovering novel diagnostic and therapeutic targets.

METHODS

We examined differences in gene expression between HCC and noncancerous liver tissue using a cDNA array with probes for 15,843 genes/clones. Two genes, osteopontin (OPN) and S100A6, were found to be >10-fold differentially expressed, and were selected for further immunohistochemical staining in 51 HCC and 10 nonmalignant liver specimens. The relation between OPN and S100A6 alterations and various clinicopathologic parameters was also evaluated.

RESULTS

We found a total of 219 genes that were differentially expressed >3-fold. Of these, 109 were upregulated and 110 downregulated. Within this group, 123 genes, including 59 upregulated and 64 downregulated, had been identified previously. These known genes were mainly involved in cell migration, cytoskeleton dynamics, the signaling pathway and cell cycle, and metabolism. OPN expression and S100A6 expression were seen in 26 of 51 (51.0 %) and 16 of 51 (31.4 %) HCC samples, respectively. More importantly, proteins coded by these genes were not found in any noncancerous liver specimen by immunohistochemical analysis. Expression of these genes correlated with poor differentiation (OPN: P = .013; S100A6: P = .008).

CONCLUSION

OPN, a secreted phosphoprotein that has been increasingly implicated in the progression and metastasis of cancer, and S100A6, a member of the S100 protein family that can perform cell proliferation, differentiation, migration, and cytoskeletal dynamics, may be promising diagnostic markers and therapeutic targets for HCC. In addition, the results encourage future studies involving the roles of these proteins in the development and progression of this cancer.

S100A6 overexpression is associated with poor prognosis and is epigenetically up-regulated in gastric cancer

S100A6 has been implicated in a variety of biological functions as well as tumorigenesis. In this study, we investigated the expression status of S100A6 in relation to the clinicopathological features and prognosis of patients with gastric cancer and further explored a possible association of its expression with epigenetic regulation. S100A6 expression was remarkably increased in 67.5% of gastric cancer tissues as compared with matched noncancerous tissues. Statistical analysis demonstrated a clear correlation between high S100A6 expression and various clinicopathological features, such as depth of wall invasion, positive lymph node involvement, liver metastasis, vascular invasion, and tumor-node metastasis stage (P < 0.05 in all cases), as well as revealed that S100A6 is an independent prognostic predictor (P = 0.026) significantly related to poor prognosis (P = 0.0004). Further exploration found an inverse relationship between S100A6 expression and the methylation status of the seventh and eighth CpG sites in the promoter/first exon and the second to fifth sites in the second exon/second intron. In addition, the level of histone H3 acetylation was found to be significantly higher in S100A6-expressing cancer cells. After 5-azacytidine or trichostatin A treatment, S100A6 expression was clearly increased in S100A6 low-expressing cells. In conclusion, our results suggested that S100A6 plays an important role in the progression of gastric cancer, affecting patient prognosis, and is up-regulated by epigenetic regulation.

Cyclophilin B as a co-regulator of prolactin-induced gene expression and function in breast cancer cells

The effects of prolactin (PRL) during the pathogenesis of breast cancer are mediated in part though Stat5 activity enhanced by its interaction with its transcriptional inducer, the prolyl isomerase cyclophilin B (CypB). We have demonstrated that knockdown of CypB decreases cell growth, proliferation, and migration, and CypB expression is associated with malignant progression of breast cancer. In this study, we examined the effect of CypB knockdown on PRL signaling in breast cancer cells. CypB knockdown with two independent siRNAs was shown to impair PRL-induced reporter expression in breast cancer cell line. cDNA microarray analysis was performed on these cells to assess the effect of CypB reduction, and revealed a significant decrease in PRL-induced endogenous gene expression in two breast cancer cell lines. Parallel functional assays revealed corresponding alterations of both anchorage-independent cell growth and cell motility of breast cancer cells. Our results demonstrate that CypB expression levels significantly modulate PRL-induced function in breast cancer cells ultimately resulting in enhanced levels of PRL-responsive gene expression, cell growth, and migration. Given the increasingly appreciated role of PRL in the pathogenesis of breast cancer, the actions of CypB detailed here are of biological significance.

S100A6 (calcyclin) deficiency induces senescence-like changes in cell cycle, morphology and functional characteristics of mouse NIH 3T3 fibroblasts

S100A6 (calcyclin) is a calcium binding protein with two EF-hand structures expressed mostly in fibroblasts and epithelial cells. We have established a NIH 3T3 fibroblast cell line stably transfected with siRNA against S100A6 to examine the effect of S100A6 deficiency on non-transformed cell physiology. We found that NIH 3T3 fibroblasts with decreased level of S100A6 manifested altered cell morphology and proliferated at a much slower pace than the control cells. Cell cycle analysis showed that a large population of these cells lost the ability to respond to serum and persisted in the G0/G1 phase. Furthermore, fibroblasts with diminished S100A6 level exhibited morphological changes and biochemical features of cellular senescence as revealed by beta-galactosidase and gelatinase assays. Also, S100A6 deficiency induced changes in the actin cytoskeleton and had a profound impact on cell adhesion and migration. Thus, we have shown that the S100A6 protein is involved in multiple aspects of fibroblast physiology and that its presence ensures normal fibroblast proliferation and function.

Proteomic profiling of cellular responses to Carvedilol enantiomers in vascular smooth muscle cells by iTRAQ-coupled 2-D LC-MS/MS

Carvedilol is a third-generation beta-blocker, with the S-enantiomer being more active than the R-enantiomer. Clinically, it has been used in the treatment of hypertension, congestive heart failure and angina pectoris. Each enantiomer of Carvedilol exhibits differential pharmacological effects. However, the cellular effects of individual enantiomer are not well understood. To gain insights into how each enantiomer affects cells, we analysed differential protein expression levels in vascular smooth muscle cells (A7r5) incubated separately with S- and R-Carvedilol by iTRAQ-coupled 2-D LC-MS/MS approach. Thirteen proteins were identified with statistically significant changes in cells incubated with S-Carvedilol, while the changes of most proteins incubated with R-Carvedilol were less significant. Among these proteins, actin in aortic smooth muscle (ACTA2), calmodulin, S100-A6, S100-A10, S100-A11, thioredoxin, lactadherin and heat-shock protein 105 kDa were found to be closely relevant with the clinical effects of Carvedilol. Furthermore, the changes in protein levels were validated by Western blot. Our findings thus provided molecular evidence on a comprehensive protein profile on Carvedilol-cell interaction, which may shed new light in molecular events underlying Carvedilol treatment.

S100A6 binds to annexin 2 in pancreatic cancer cells and promotes pancreatic cancer cell motility

Background:

High levels of S100A6 have been associated with poor outcome in pancreatic cancer patients. The functional role of S100A6 is, however, poorly understood.

Methods:

Immunoprecipitation followed by two-dimensional gel electrophoresis and mass spectrometry were undertaken to identify S100A6 interacting proteins in pancreatic cancer cells. Immunohistochemistry and coimmunofluorescence were performed to examine expression or colocalisation of proteins. siRNA was used to deplete specific proteins and effects on motility were measured using Boyden Chamber and wound healing assays.

Results:

Our proteomic screen to identify S100A6 interacting proteins revealed annexin 11, annexin 2, tropomyosin β and a candidate novel interactor lamin B1. Of these, annexin 2 was considered particularly interesting, as, like S100A6, it is expressed early in the development of pancreatic cancer and overexpression occurs with high frequency in invasive cancer. Reciprocal immunoprecipitation confirmed the interaction between annexin 2 and S100A6 and the proteins colocalised, particularly in the plasma membrane of cultured pancreatic cancer cells and primary pancreatic tumour tissue. Analysis of primary pancreatic cancer specimens (n=55) revealed a strong association between high levels of cytoplasmic S100A6 and the presence of annexin 2 in the plasma membrane of cancer cells (P=0.009). Depletion of S100A6 was accompanied by diminished levels of membrane annexin 2 and caused a pronounced reduction in the motility of pancreatic cancer cells.

Conclusion:

These findings point towards a functional role for S100A6 that may help explain the link between S100A6 expression in pancreatic cancer and aggressive disease.

Biomarker discovery in asthma-related inflammation and remodeling

Asthma is a complex inflammatory disease of airways. A network of reciprocal interactions between inflammatory cells, peptidic mediators, extracellular matrix components, and proteases is thought to be involved in the installation and maintenance of asthma-related airway inflammation and remodeling. To date, new proteic mediators displaying significant activity in the pathophysiology of asthma are still to be unveiled. The main objective of this study was to uncover potential target proteins by using surface-enhanced laser desorption/ionization-time of flight-mass spectrometry (SELDI-TOF-MS) on lung samples from mouse models of allergen-induced airway inflammation and remodeling. In this model, we pointed out several protein or peptide peaks that were preferentially expressed in diseased mice as compared to controls. We report the identification of different five proteins: found inflammatory zone 1 or RELM alpha (FIZZ-1), calcyclin (S100A6), clara cell secretory protein 10 (CC10), Ubiquitin, and Histone H4.