ABSTRACT
BACKGROUND: Intervertebral disc degeneration (IDD) is a common musculoskeletal degenerative disease, which often leads to low back pain and even disability, resulting in loss of labor ability and decreased quality of life. Although many progresses have been made in the current research, the underlying mechanism of IDD remains unclear. The apoptosis of nucleus pulposus (NP) cells (NPCs) is an important pathological mechanism in intervertebral disc degeneration (IDD). This study evaluated the relationship between S100A6 and NPCs and its underlying mechanism. METHODS: Mass spectrometry, bioinformatics, and quantitative real-time polymerase chain reaction (qRT-PCR) analyses were used to screen and verify hub genes for IDD in human IVD specimens with different degeneration degrees. Western blotting, immunohistochemistry (IHC), and/or immunofluorescence (IF) were used to detect the expression level of S100A6 in human NP tissues and NPCs. The apoptotic phenotype of NPCs and Wnt/ß-catenin signaling pathway were evaluated using flow cytometry, western blotting, and IF. S100A6 was overexpressed or knocked down in NPCs to determine its impact on apoptosis and Wnt/ß-catenin signaling pathway activity. Moreover, we used the XAV-939 to inhibit and SKL2001 to activate the Wnt/ß-catenin signaling pathway. The therapeutic effect of S100A6 inhibition on IDD was also evaluated. RESULTS: S100A6 expression increased in IDD. In vitro, increased S100A6 expression promoted apoptosis in interleukin (IL)-1ß-induced NPCs. In contrast, the inhibition of S100A6 expression partially alleviated the progression of annulus fibrosus (AF) puncture-induced IDD in rats. Mechanistic studies revealed that S100A6 regulates NPC apoptosis via Wnt/ß-catenin signaling pathway. CONCLUSIONS: This study showed that S100A6 expression increased during IDD and promoted NPCs apoptosis by regulating the Wnt/ß-catenin signaling pathway, suggesting that S100A6 is a promising new therapeutic target for IDD.
Subject(s)
Apoptosis , Intervertebral Disc Degeneration , Nucleus Pulposus , S100 Calcium Binding Protein A6 , Wnt Signaling Pathway , Nucleus Pulposus/metabolism , Nucleus Pulposus/pathology , Apoptosis/genetics , Humans , S100 Calcium Binding Protein A6/metabolism , S100 Calcium Binding Protein A6/genetics , Intervertebral Disc Degeneration/metabolism , Intervertebral Disc Degeneration/genetics , Intervertebral Disc Degeneration/pathology , Animals , Male , Female , Rats , Adult , Middle Aged , beta Catenin/metabolism , beta Catenin/genetics , Rats, Sprague-Dawley , Disease Models, Animal , Cell Cycle ProteinsABSTRACT
Background: Immunotherapy plays a significant role in the treatment of hepatocellular carcinoma (HCC). Members of the S100 protein family (S100s) have been widely implicated in the pathogenesis and progression of tumors. However, the exact mechanism by which S100s contribute to tumor immunity remains unclear. Methods: To explore the role of S100s in HCC immune cells, we collected and comparatively analyzed single-cell RNA sequencing (scRNA-seq) data of HCC and hepatitis B virus-associated HCC. By mapping cell classification and searching for S100s binding targets and downstream targets. Results: S100A6/S100A11 was differentially expressed in tumor T cells and involved in the nuclear factor (NF) κB pathway. Further investigation of the TCGA dataset revealed that patients with low S100A6/S100A11 expression had a better prognosis. Temporal cell trajectory analysis showed that the activation of the NF-κB pathway is at a critical stage and has an important impact on the tumor microenvironment. Conclusion: Our study revealed that S100A6/S100A11 could be involved in regulating the differentiation and cellular activity of T-cell subpopulations in HCC, and its low expression was positively correlated with prognosis. It may provide a new direction for immunotherapy of HCC and a theoretical basis for future clinical applications.
Subject(s)
Carcinoma, Hepatocellular , Liver Neoplasms , RNA-Seq , S100 Calcium Binding Protein A6 , S100 Proteins , Humans , Biomarkers, Tumor , Carcinoma, Hepatocellular/genetics , Carcinoma, Hepatocellular/immunology , Carcinoma, Hepatocellular/pathology , Carcinoma, Hepatocellular/metabolism , Carcinoma, Hepatocellular/etiology , Cell Cycle Proteins , Computational Biology , Gene Expression Profiling , Gene Expression Regulation, Neoplastic , Liver Neoplasms/genetics , Liver Neoplasms/immunology , Liver Neoplasms/pathology , Liver Neoplasms/metabolism , NF-kappa B/metabolism , Prognosis , S100 Calcium Binding Protein A6/genetics , S100 Calcium Binding Protein A6/metabolism , S100 Proteins/genetics , S100 Proteins/metabolism , Signal Transduction , Single-Cell Analysis , Tumor Microenvironment/immunology , Tumor Microenvironment/geneticsABSTRACT
PURPOSE: To investigate the mechanism by which S100 calcium-binding protein A6 (S100A6) affects colorectal cancer (CRC) cells to oxaliplatin (L-OHP) chemotherapy, and to explore new strategies for CRC treatment. METHODS: S100A6 expression was assessed in both parental and L-OHP-resistant CRC cells using western blotting, quantitative real-time polymerase chain reaction (qRT-PCR), and enzyme-linked immunosorbent assays (ELISA). Lentiviral vectors were utilized to induce the knockdown of S100A6 expression, followed by comprehensive evaluations of cell proliferation, apoptosis, and epithelial-mesenchymal transition (EMT). Additionally, RNA-seq analysis was conducted to identify genes associated with the knockdown of S100A6. RESULTS: Elevated S100A6 expression in CRC tissues correlated with an adverse prognosis in patients with CRC. Higher expression of S100A6 was also observed in L-OHP-resistant CRC cells, which showed enhanced proliferation, migration, invasion, and antiapoptotic capabilities. Notably, the knockdown of S100A6 expression resulted in decreased proliferation, increased apoptosis, and suppression of EMT and tumorigenicity in L-OHP-resistant CRC cells. Transcriptome sequencing reveals a noteworthy association between S100A6 and vimentin expression. Application of the EMT agonist, transforming growth factor ß (TGF-ß), induces EMT in CRC cells. S100A6 expression positively correlates with TGF-ß expression. TGF-ß facilitated the expression of EMT-related molecules and reduced the chemosensitivity of L-OHP in S100A6-knockdown cells. CONCLUSION: In conclusion, the knockdown of S100A6 may overcome the L-OHP resistance of CRC cells by modulating EMT.
Subject(s)
Apoptosis , Cell Cycle Proteins , Cell Proliferation , Colorectal Neoplasms , Drug Resistance, Neoplasm , Epithelial-Mesenchymal Transition , Oxaliplatin , S100 Calcium Binding Protein A6 , Epithelial-Mesenchymal Transition/drug effects , Humans , Oxaliplatin/pharmacology , Colorectal Neoplasms/genetics , Colorectal Neoplasms/drug therapy , Colorectal Neoplasms/pathology , Colorectal Neoplasms/metabolism , Drug Resistance, Neoplasm/genetics , S100 Calcium Binding Protein A6/genetics , S100 Calcium Binding Protein A6/metabolism , Cell Line, Tumor , Cell Proliferation/drug effects , Apoptosis/drug effects , Gene Expression Regulation, Neoplastic/drug effects , Cell Movement/drug effects , Animals , Antineoplastic Agents/pharmacology , Female , Male , Mice , Gene Knockdown Techniques , Vimentin/metabolism , Vimentin/genetics , Prognosis , Transforming Growth Factor beta/metabolismABSTRACT
Objective: Calprotectin (CLP), S100A6, and high mobility group nucleosome-binding protein 1 (HMGN1), known as alarmins, are involved in the pathogenesis of many tumors. In this study, we aimed to investigate the relationships of serum CLP, S100A6, and HMGN1 levels with the clinical and laboratory findings of patients with multiple myeloma (MM) and their roles in the pathogenesis of MM. Materials and Methods: We measured the serum CLP, S100A6, and HMGN1 levels of 55 newly diagnosed patients and 32 healthy controls using the sandwich enzyme-linked immunosorbent assay method. The medical records of the patients were also reviewed. Results: Serum CLP, S100A6, and HMGN1 levels were significantly decreased in MM patients compared to the control group (p=0.012, p=0.001, and p=0.030, respectively). Receiver operating characteristic analysis was used to determine diagnostic cut-off values for serum CLP, S100A6, and HMGN1 of <98 ng/mL (area under the curve [AUC]: 0.663, 95% confidence interval [CI]: 0.554-0.761, p=0.009), <1174.5 pg/mL (AUC: 0.706, 95% CI: 0.598-0.799, p=0.001), and <440.18 pg/mL (AUC: 0.640, 95% CI: 0.530-0.740, p=0.03), respectively. CLP levels were found to be statistically significantly higher in patients with light chain MM (91.58±22.57 ng/mL) compared to heavy chain MM (79.42±15.83 ng/mL) (p=0.03). A negative correlation was observed between CLP and M protein, immunoglobulin G, globulin, and beta-2 microglobulin (correlation coefficients: -0.361, -0.370, -0.279, -0.300, respectively; p=0.024, p=0.06, p=0.04, p=0.0033). Conclusion: In this study, we found that serum CLP, S100A6, and HMGN1 levels were statistically lower in patients with newly diagnosed MM compared to the control group. These results suggest that CLP may bind to the paraprotein produced by heavy chain MM in the blood, causing its blood levels to be low. Additionally, low levels of HMGN1, which is involved in DNA repair, suggest that HMGN1 may contribute to the complex genetic abnormalities found in cases of MM.
Subject(s)
Alarmins , Multiple Myeloma , Humans , Multiple Myeloma/blood , Multiple Myeloma/diagnosis , Female , Male , Middle Aged , Alarmins/blood , Aged , Leukocyte L1 Antigen Complex/blood , ROC Curve , Biomarkers, Tumor/blood , Case-Control Studies , HMGN1 Protein/blood , Adult , S100 Calcium Binding Protein A6/blood , Cell Cycle ProteinsABSTRACT
Patients diagnosed with lymph node (LN) metastatic liver cancer face an exceedingly grim prognosis. In-depth analysis of LN metastatic patients' characteristics and tumor cells' interactions with human lymphatic endothelial cells (HLECs), can provide important biological and therapeutic insights. Here we identify at the single-cell level that S100A6 expression differs between primary tumor and their LN metastasis. Of particular significance, we uncovered the disparity in S100A6 expression between tumors and normal tissues is greater in intrahepatic cholangiocarcinoma (ICC) patients, frequently accompanied by LN metastases, than that in hepatocellular carcinoma (HCC), with rare occurrence of LN metastasis. Furthermore, in the infrequent instances of LN metastasis in HCC, heightened S100A6 expression was observed, suggesting a critical role of S100A6 in the process of LN metastasis. Subsequent experiments further uncovered that S100A6 secreted from tumor cells promotes lymphangiogenesis by upregulating the expression and secretion of vascular endothelial growth factor-D (VEGF-D) in HLECs through the RAGE/NF-kB/VEGF-D pathway while overexpression of S100A6 in tumor cells also augmented their migration and invasion. Taken together, these data reveal the dual effects of S100A6 in promoting LN metastasis in liver cancer, thus highlighting its potential as a promising therapeutic target.
Subject(s)
Bile Duct Neoplasms , Carcinoma, Hepatocellular , Liver Neoplasms , Humans , Vascular Endothelial Growth Factor D/metabolism , Vascular Endothelial Growth Factor D/pharmacology , Lymphatic Metastasis , Liver Neoplasms/genetics , Liver Neoplasms/metabolism , NF-kappa B/metabolism , Carcinoma, Hepatocellular/genetics , Carcinoma, Hepatocellular/metabolism , Endothelial Cells/metabolism , Lymphangiogenesis , Bile Duct Neoplasms/pathology , Bile Ducts, Intrahepatic/pathology , S100 Calcium Binding Protein A6/metabolism , S100 Calcium Binding Protein A6/pharmacology , Cell Cycle Proteins/metabolismABSTRACT
S100 is a family of over 20 structurally homologous, but functionally diverse regulatory (calcium/zinc)-binding proteins of vertebrates. The involvement of S100 proteins in numerous vital (patho)physiological processes is mediated by their interaction with various (intra/extra)cellular protein partners, including cell surface receptors. Furthermore, recent studies have revealed the ability of specific S100 proteins to modulate cell signaling via direct interaction with cytokines. Previously, we revealed the binding of ca. 71% of the four-helical cytokines via the S100P protein, due to the presence in its molecule of a cytokine-binding site overlapping with the binding site for the S100P receptor. Here, we show that another S100 protein, S100A6 (that has a pairwise sequence identity with S100P of 35%), specifically binds numerous four-helical cytokines. We have studied the affinity of the recombinant forms of 35 human four-helical cytokines from all structural families of this fold to Ca2+-loaded recombinant human S100A6, using surface plasmon resonance spectroscopy. S100A6 recognizes 26 of the cytokines from all families of this fold, with equilibrium dissociation constants from 0.3 nM to 12 µM. Overall, S100A6 interacts with ca. 73% of the four-helical cytokines studied to date, with a selectivity equivalent to that for the S100P protein, with the differences limited to the binding of interleukin-2 and oncostatin M. The molecular docking study evidences the presence in the S100A6 molecule of a cytokine-binding site, analogous to that found in S100P. The findings argue the presence in some of the promiscuous members of the S100 family of a site specific to a wide range of four-helical cytokines. This unique feature of the S100 proteins potentially allows them to modulate the activity of the numerous four-helical cytokines in the disorders accompanied by an excessive release of the cytokines.
Subject(s)
Immunologic Factors , S100 Proteins , Humans , Animals , S100 Calcium Binding Protein A6 , Molecular Docking Simulation , Binding Sites , Cell Cycle ProteinsABSTRACT
BACKGROUND: S100 calcium-binding protein A6 (S100A6) is a calcium-binding protein that is involved in a variety of cellular processes, such as proliferation, apoptosis, and the cellular response to various stress stimuli. However, its role in NAFLD and associated metabolic diseases remains uncertain. METHODS AND RESULTS: In this study, we revealed a new function and mechanism of S100A6 in NAFLD. S100A6 expression was upregulated in human and mouse livers with hepatic steatosis, and the depletion of hepatic S100A6 remarkably inhibited lipid accumulation, insulin resistance, inflammation, and obesity in a high-fat, high-cholesterol (HFHC) diet-induced murine hepatic steatosis model. In vitro mechanistic investigations showed that the depletion of S100A6 in hepatocytes restored lipophagy, suggesting S100A6 inhibition could alleviate HFHC-induced NAFLD. Moreover, S100A6 liver-specific ablation mediated by AAV9 alleviated NAFLD in obese mice. CONCLUSIONS: Our study demonstrates that S100A6 functions as a positive regulator of NAFLD, targeting the S100A6-lipophagy axis may be a promising treatment option for NAFLD and associated metabolic diseases.
Subject(s)
Non-alcoholic Fatty Liver Disease , S100 Calcium Binding Protein A6 , Animals , Humans , Mice , Apoptosis , Autophagy , Calcium-Binding Proteins/genetics , S100 Calcium Binding Protein A6/metabolismABSTRACT
S100A6, also known as calcyclin, is a low-molecular-weight Ca2+-binding protein from the S100 family that contains two EF-hands. S100A6 is expressed in a variety of mammalian cells and tissues. It is also expressed in lung, colorectal, pancreatic, and liver cancers, as well as other cancers such as melanoma. S100A6 has many molecular functions related to cell proliferation, the cell cycle, cell differentiation, and the cytoskeleton. It is not only involved in tumor invasion, proliferation, and migration, but also the pathogenesis of other non-neoplastic diseases. In this review, we focus on the molecular mechanisms and potential therapeutic targets of S100A6 in tumors, nervous system diseases, leukemia, endometriosis, cardiovascular disease, osteoarthritis, and other related diseases.
Subject(s)
Liver Neoplasms , S100 Calcium Binding Protein A6 , Animals , Female , Humans , Cell Cycle , Cell Cycle Proteins/metabolism , Cell Differentiation , Cell Proliferation , Mammals/metabolism , S100 Calcium Binding Protein A6/metabolism , S100 Proteins/metabolismABSTRACT
Mutations in the proline-rich domain (PRD) of annexin A11 are linked to amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease, and generate abundant neuronal A11 inclusions by an unknown mechanism. Here, we demonstrate that recombinant A11-PRD and its ALS-associated variants form liquidlike condensates that transform into ß-sheet-rich amyloid fibrils. Surprisingly, these fibrils dissolved in the presence of S100A6, an A11 binding partner overexpressed in ALS. The ALS variants of A11-PRD showed longer fibrillization half-times and slower dissolution, even though their binding affinities for S100A6 were not significantly affected. These findings indicate a slower fibril-to-monomer exchange for these ALS variants, resulting in a decreased level of S100A6-mediated fibril dissolution. These ALS-A11 variants are thus more likely to remain aggregated despite their slower fibrillization.
Subject(s)
Amyotrophic Lateral Sclerosis , Neurodegenerative Diseases , Humans , Amyotrophic Lateral Sclerosis/genetics , Amyotrophic Lateral Sclerosis/metabolism , Annexins/genetics , Solubility , Amyloid/metabolism , Proline/genetics , S100 Calcium Binding Protein A6 , Cell Cycle Proteins/chemistry , Cell Cycle Proteins/metabolismABSTRACT
Background: Cholangiocarcinoma (CCA) represents the epithelial cell cancer with high aggressiveness whose five-year survival rate is poor with standard treatment. Calcyclin-binding protein (CACYBP) shows aberrant expression within several malignant tumors, but the role of CACYBP in CCA remains unknown. Methods: Immunohistochemical (IHC) analysis was used to identify CACYBP overexpression in clinical samples of CCA patients. Moreover, its correlation with clinical outcome was revealed. Furthermore, CACYBP's effect on CCA cell growth and invasion was investigated in vitro and in vivo using loss-of-function experiments. Results: CACYBP showed up-regulation in CCA, which predicts the dismal prognostic outcome. CACYBP had an important effect on in-vitro and in-vivo cancer cell proliferation and migration. Additionally, knockdown of CACYBP weakened protein stability by promoting ubiquitination of MCM2. Accordingly, MCM2 up-regulation partly reversed CACYBP deficiency's inhibition against cancer cell viability and invasion. Thus, MCM2 might drive CCA development by Wnt/ß-catenin pathway. Conclusions: CACYBP exerted a tumor-promoting role in CCA by suppressing ubiquitination of MCM2 and activating Wnt/ß-catenin pathway, hence revealing that it may be the possible therapeutic target for CCA treatment.
Subject(s)
Bile Duct Neoplasms , Cholangiocarcinoma , Humans , S100 Calcium Binding Protein A6 , beta Catenin , Cholangiocarcinoma/genetics , Ubiquitination , Bile Duct Neoplasms/genetics , Bile Ducts, Intrahepatic , Minichromosome Maintenance Complex Component 2 , Calcium-Binding Proteins/geneticsABSTRACT
BACKGROUND: S100A6 and murine double minute 2 (MDM2) are important cancer-related molecules. A previous study identified an interaction between S100A6 and MDM2 by size exclusion chromatography and surface plasmon resonance experiments. The present study investigated whether S100A6 could bind to MDM2 in vivo and further explored its functional implication. METHODS: Co-immunoprecipitation, glutathione-S-transferase pull-down assay, and immunofluorescence were performed to determine the in vivo interaction between S100A6 and MDM2. Cycloheximide pulse-chase assay and ubiquitination assay were performed to clarify the mechanism by which S100A6 downregulated MDM2. In addition, clonogenic assay, WST-1 assay, and flow cytometry of apoptosis and the cell cycle were performed and a xenograft model was established to evaluate the effects of the S100A6/MDM2 interaction on growth and paclitaxel-induced chemosensitivity of breast cancer. The expressions of S100A6 and MDM2 in patients with invasive breast cancer were analyzed by immunohistochemistry. In addition, the correlation between the expression of S100A6 and the response to neoadjuvant chemotherapy was statistically analyzed. RESULTS: S100A6 promoted the MDM2 translocation from nucleus to cytoplasm, in which the S100A6 bound to the binding site of the herpesvirus-associated ubiquitin-specific protease (HAUSP) in MDM2, disrupted the MDM2-HAUSP-DAXX interactions, and induced the MDM2 self-ubiquitination and degradation. Furthermore, the S100A6-mediated MDM2 degradation suppressed the growth of breast cancer and enhanced its sensitivity to paclitaxel both in vitro and in vivo. For patients with invasive breast cancer who received epirubicin and cyclophosphamide followed by docetaxel (EC-T), expressions of S100A6 and MDM2 were negatively correlated, and high expression of S100A6 suggested a higher rate of pathologic complete response (pCR). Univariate and multivariate analyses showed that the high expression of S100A6 was an independent predictor of pCR. CONCLUSION: These results reveal a novel function for S100A6 in downregulating MDM2, which directly enhances sensitivity to chemotherapy.
Subject(s)
Breast Neoplasms , Animals , Female , Humans , Mice , Apoptosis , Breast Neoplasms/drug therapy , Breast Neoplasms/genetics , Breast Neoplasms/metabolism , Cell Cycle Proteins/metabolism , Cell Line, Tumor , Paclitaxel/pharmacology , Paclitaxel/therapeutic use , Proto-Oncogene Proteins c-mdm2/genetics , Proto-Oncogene Proteins c-mdm2/metabolism , S100 Calcium Binding Protein A6/metabolism , Tumor Suppressor Protein p53/genetics , UbiquitinationABSTRACT
BACKGROUND AND PURPOSE: Repeated amino acid sequences in proteins are widely found, and the glycine-serine-alanine repeat is an element with a general propensity to form ß-sheet aggregates as found in key pathological factors, in several neurodegenerative diseases. Such properties of this repeat may guide development of disease-modifying therapies for neurodegenerative disease. However, details of its role and underlying mechanism(s) remain largely unknown. EXPERIMENTAL APPROACH: Actions of specific glycine-serine-alanine repeat peptides (SNPs), especially SNP-9, on Alzheimer's disease (AD)-like abnormalities were evaluated in transgenic mice and Caenorhabditis elegans, and in rat and cell models. Entry of SNPs into the brain, SNP activity in neuronal cells and peptide entry into cells were analysed in vivo and in vitro. Cell-free systems and the yeast two-hybrid system were also used to explore possible targets of SNP-9, and interactions of potential targets with SNP-9 were confirmed in cell-based systems. KEY RESULTS: We first identified SNP-9 as a potent neuroprotective peptide with the activity to decrease oligomeric amyloid ß (Aß) via co-assembling with the toxic Aß oligomer to form hetero-oligomers. Also, calcyclin-binding protein was found to act as a SNP-9-binding protein, by screening of a human brain cDNA library. Such binding showed that SNP-9 could regulate the abnormal hyperphosphorylation of tau via calcyclin-binding protein. CONCLUSION AND IMPLICATIONS: Our study provides a foundation for development of SNPs, especially SNP-9, as potential therapeutic interventions for AD. We propose SNP-9 as a potential therapeutic agent for the treatment of AD.
Subject(s)
Alzheimer Disease , Neurodegenerative Diseases , Mice , Rats , Animals , Humans , Alzheimer Disease/metabolism , Amyloid beta-Peptides/metabolism , Serine , S100 Calcium Binding Protein A6 , Mice, Transgenic , Caenorhabditis elegans/metabolismABSTRACT
INTRODUCTION: Autoimmune encephalitis (AE) is caused by autoantibodies attacking neuronal cell surface antigens and/or synaptic antigens. We previously demonstrated that S100A6 was hypomethylated in patients with AE and that it promoted B lymphocyte infiltration through the simulated blood-brain barrier (BBB). In this study, we focused on the epigenetic regulation of S100A6, the process by which S100A6 affects B lymphocyte infiltration, and the therapeutic potential of S100A6 antibodies. METHODS: We enrolled and collected serum from 10 patients with AE and 10 healthy control (HC) subjects. Promoter methylation and 5-azacytidine treatment assays were conducted to observe the methylation process of S100A6. The effect of S100A6 on B lymphocytes was analyzed using an adhesion assay and leukocyte transendothelial migration (LTEM) assay. A LTEM assay was also used to compare the effects of the serum of HCs, serum of AE patients, S100A6 recombinant protein, and S100A6 antibodies on B lymphocytes. RESULT: The promoter methylation and 5-azacytidine treatment assays confirmed that S100A6 was regulated by DNA methylation. The adhesion study demonstrated that the addition of S100A6 enhanced adhesion between B lymphocytes and a BBB endothelial cell line in a concentration-dependent manner. The LTEM assay showed that the serum of AE patients, as well as S100A6, promoted B lymphocyte infiltration and that this effect could be attenuated by S100A6 antibodies. CONCLUSION: We clarified that S100A6 was under epigenetic regulation in patients with AE and that it helped B lymphocytes to adhere to and infiltrate the BBB endothelial layer, which could be counteracted by S100A6 antibodies. Therefore, the methylation profile of S100A6 could be a marker of the activity of AE, and countering the effect of S100A6 may be a potential treatment target for AE.
Subject(s)
Autoimmune Diseases of the Nervous System , S100 Proteins , Humans , S100 Proteins/genetics , S100 Proteins/metabolism , Cell Cycle Proteins/genetics , Epigenesis, Genetic , S100 Calcium Binding Protein A6/genetics , S100 Calcium Binding Protein A6/metabolism , Autoantibodies/metabolism , AzacitidineABSTRACT
High levels of S100A6 have been associated with progression in some types of human cancers. Cancers related to S100A6 have been reported to include lung cancer, cervical cancer, pancreatic cancer, gastric cancer, colon cancer, etc., but its role in the molecular pathogenesis of these cancers is largely unknown. This study investigated the expression and functional roles of S100A6 in human thyroid cancer. The expression level of S100A6 in thyroid cancer cells was determined by bioinformatics and transcriptomic analysis. Furthermore, the potential functions of S100A6 in tumorigenesis were analyzed by cell proliferation, migration, invasion, and Western blot assays in human thyroid cancer cells. Public database queries revealed high S100A6 expression in thyroid cancer. In addition, we also found that high expression of S100A6 was positively correlated with malignant clinicopathological characteristics of thyroid cancer in The Cancer Genome Atlas database. qPCR results confirmed the high expression of S100A6 in thyroid cancer cells. S100A6 silencing inhibited cell proliferation, migration, and invasion. Western blot assays and response experiments showed that S100A6 promotes cell proliferation and tumorigenicity partly through the PI3K/AKT/mTOR signaling pathway. These results suggest that S100A6 affects the progression of thyroid cancer and can be used as a target in the future treatment of thyroid cancer.
Subject(s)
S100 Calcium Binding Protein A6 , Thyroid Neoplasms , Humans , Apoptosis/genetics , Cell Cycle Proteins/metabolism , Cell Line, Tumor , Cell Movement , Cell Proliferation , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Thyroid Neoplasms/genetics , TOR Serine-Threonine Kinases/metabolismABSTRACT
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.
Subject(s)
Neoplasms , S100 Proteins , Humans , S100 Calcium Binding Protein A6/metabolism , Ligands , S100 Proteins/chemistry , Cell Cycle Proteins/metabolism , Signal TransductionABSTRACT
Malaria remains as a global life-threatening disorder due to the emergence of resistance against standard antimalarials. Consequently, there is a serious need to better understand the biology of the malaria parasite in order to determine appropriate targets for new interventions. Calcyclin binding protein (CacyBP) is a multi-functional and multi-ligand protein that is not well characterized in malaria disease. In this study, we have cloned CacyBP from rodent species Plasmodium yoelii nigeriensis and purified the recombinant protein to carry out its detailed molecular, biophysical and immunological characterization. Molecular characterization indicates that PyCacyBP is a â¼27 kDa protein in parasite lysate and exists in monomer and dimer forms. Bioinformatic analysis of CacyBP showed significant sequence and structural similarities between rodent and human malaria parasites. CacyBP is expressed in all blood stages of P. yoelii nigeriensis parasite. In silico studies proposed the immunogenic potential of CacyBP. The rPyCacyBP immunized mice exhibited elevated levels of IgG1, IgG2a, IgG2b and IgG3 in their serum. Notably, cellular immune response in splenocytes from immunized mice showed increased expression of pro-inflammatory cytokines such as IL-12, IFN-γ and TNF-α. This CacyBP exhibited pro-inflammatory immune response in rodent host. These finding revealed that CacyBP may have the potential to boost the host immunity for protection against malaria infection. The present study provides basis for further exploration of the biological function of CacyBP in malaria parasite.
Subject(s)
Antimalarials , Malaria , Parasites , Plasmodium yoelii , Humans , Animals , Mice , Parasites/metabolism , S100 Calcium Binding Protein A6 , Malaria/drug therapy , Antimalarials/therapeutic use , Immunity, Cellular , Plasmodium yoelii/genetics , Calcium-Binding Proteins/metabolism , Calcium-Binding Proteins/therapeutic useABSTRACT
Fructokinase (FRK) activates fructose through phosphorylation, which sends the activated fructose into primary metabolism and regulates fructose signaling capabilities in plants. The apple (Malus × domestica) FRK gene MdFRK2 shows especially high affinity to fructose, and its overexpression decreases fructose levels in the leaves of young plants. However, in the current study of mature plants, fruits of transgenic apple trees overexpressing MdFRK2 accumulated a higher level of fructose than wild-type (WT) fruits (at both young and mature stages). Transgenic apple trees with high mRNA MdFRK2 expression showed no significant differences in MdFRK2 protein abundance or FRK enzyme activity compared to WT in mature leaves, young fruits, and mature fruits. Immunoprecipitation-mass spectrometry analysis identified an skp1, cullin, F-box (SCF) E3 ubiquitin ligase, calcyclin-binding protein (CacyBP), that interacted with MdFRK2. RNA-sequencing analysis provided evidence for ubiquitin-mediated post-transcriptional regulation of MdFRK2 protein for the maintenance of fructose homeostasis in mature leaves and fruits. Further analyses suggested an MdCacyBP-MdFRK2 regulatory module, in which MdCacyBP interacts with and ubiquitinates MdFRK2 to facilitate its degradation by the 26S proteasome, thus decreasing the FRK enzyme activity to elevate fructose concentration in transgenic apple trees. This result uncovered an important mechanism underlying plant fructose homeostasis in different organs through regulating the MdFRK2 protein level via ubiquitination and degradation. Our study provides usable data for the future improvement of apple flavor and expands our understanding of the molecular mechanisms underlying plant fructose content and signaling regulation.
Subject(s)
Malus , Malus/metabolism , S100 Calcium Binding Protein A6/genetics , S100 Calcium Binding Protein A6/metabolism , Homeostasis , Fructose , Sugars/metabolism , Gene Expression Regulation, Plant , Plant Proteins/metabolismABSTRACT
Receptor for advanced glycation end products (RAGE), a member of the immunoglobulin family, interactions with its ligands trigger downstream signaling and induce an inflammatory response linked to diabetes, inflammation, carcinogenesis, cardiovascular disease, and a variety of other human disorders. The interaction of RAGE and S100A6 has been associated with a variety of malignancies. For the control of RAGE-related illnesses, there is a great demand for more specialized drug options. To identify the most effective target for combating human malignancies associated with RAGE-S100A6 complex, we conducted single and differential gene expression analyses of S100A6 and RAGE, comparing normal and malignant tissues. Further, a structure-based virtual screening was conducted using the ZINC15 database. The chosen compounds were then subjected to a molecular docking investigation on the RAGE active site region, recognized by the various cancer-related RAGE ligands. An optimized RAGE structure was screened against a library of drug-like molecules. The screening results suggested that three promising compounds were presented as the top acceptable drug-like molecules with a high binding affinity at the RAGE V-domain catalytic region. We depicted that these compounds may be potential RAGE inhibitors and could be used to produce a successful medication against human cancer and other RAGE-related diseases based on their various assorted parameters, binding energy, hydrogen bonding, ADMET characteristics, etc. MD simulation on a time scale of 50 ns was used to test the stability of the RAGE-inhibitor complexes. Therefore, targeting RAGE and its ligands using these drug-like molecules may be an effective therapeutic approach.
Subject(s)
Antineoplastic Agents , Neoplasms , Humans , Receptor for Advanced Glycation End Products/metabolism , Molecular Docking Simulation , Protein Binding , Ligands , Gene Expression Profiling , S100 Calcium Binding Protein A6/genetics , S100 Calcium Binding Protein A6/metabolism , Cell Cycle Proteins/geneticsABSTRACT
Nonalcoholic fatty liver disease (NAFLD) is an independent predictor of systemic insulin resistance and type 2 diabetes mellitus (T2DM). However, converse correlates between excess liver fat content and ß-cell function remain equivocal. Specifically, how the accumulation of liver fat consequent to the enhanced de novo lipogenesis (DNL) leads to pancreatic ß-cell failure and eventually to T2DM is elusive. Here, we have identified that low-molecular-weight calcium-binding protein S100A6, or calcyclin, inhibits glucose-stimulated insulin secretion (GSIS) from ß cells through activation of the receptor for the advanced glycation end products and diminution of mitochondrial respiration. Serum S100A6 level is elevated both in human patients with NAFLD and in a high-fat diet-induced mouse model of NAFLD. Although serum S100A6 levels are negatively associated with ß-cell insulin secretory capacity in human patients, depletion of hepatic S100A6 improves GSIS and glycemia in mice, suggesting that S100A6 contributes to the pathophysiology of diabetes in NAFLD. Moreover, transcriptional induction of hepatic S100A6 is driven by the potent regulator of DNL, carbohydrate response element-binding protein (ChREBP), and ectopic expression of ChREBP in the liver suppresses GSIS in a S100A6-sensitive manner. Together, these data suggest elevated serum levels of S100A6 may serve as a biomarker in identifying patients with NAFLD with a heightened risk of developing ß-cell dysfunction. Overall, our data implicate S100A6 as, to our knowledge, a hitherto unknown hepatokine to be activated by ChREBP and that participates in the hepato-pancreatic communication to impair insulin secretion and drive the development of T2DM in NAFLD.
Subject(s)
Non-alcoholic Fatty Liver Disease , S100 Calcium Binding Protein A6 , Animals , Humans , Mice , Blood Glucose/metabolism , Cell Cycle Proteins/metabolism , Diabetes Mellitus, Type 2/metabolism , Glycation End Products, Advanced/metabolism , Insulin/metabolism , Insulin Resistance/physiology , Lipogenesis/physiology , Liver/metabolism , Non-alcoholic Fatty Liver Disease/metabolism , S100 Calcium Binding Protein A6/metabolismABSTRACT
Adult or tissue stem cells are present in various tissues of the organism where they reside in a specific environment called the niche. Owing to their ability to generate a progeny that can proliferate and differentiate into specialized cell types, adult stem cells constitute a source of new cells necessary for tissue maintenance and/or regeneration. Under normal conditions they divide with a frequency matching the pace of tissue renewal but, following tissue damage, they can migrate to the site of injury and expand/divide intensively to facilitate tissue repair. For this reason much hope is being placed on the use of adult stem cells in regenerative therapies, including tissue engineering. Identification and characterization of tissue stem cells has been a laborious process due to their scarcity and lack of universal markers. Nonetheless, recent studies, employing various types of transcriptomic analyses, revealed some common trends in gene expression pattern among stem cells derived from different tissues, suggesting the importance of certain genes/proteins for the unique properties of these cells. S100A6, a small calcium binding protein, has been recognized as an important factor influencing cell proliferation and differentiation. Accumulating results show that S100A6 is a constituent of adult stem cells and, in some cases, may even be considered as their marker. Thus, in this review we summarize literature data concerning the presence of S100A6 in adult and cancer stem cells and speculate on its potential role and usefulness as a marker of these cells.