Polyhedral magnetic nanoparticles induce apoptosis in gastric cancer stem cells and suppressing tumor growth through magnetic force generation.

Gastric cancer is a prevalent malignant tumor worldwide, posing challenges due to its poor prognosis and limited treatment options. Cancer stem cells (CSCs) were demonstrated as a subset of cancer cells responsible for tumor initiation and progression, and their inherent resistance to conventional chemotherapy and radiotherapy critically contributes to tumor recurrence and metastasis. Promoting the eradication of cancer stem cells is crucial for enhancing the efficacy of cancer treatments. This study introduces a novel therapeutic strategy utilizing polyhedral magnetic nanoparticles (PMNPs) functionalized with CD44 antibodies and cell-penetrating peptides (CPPs) to improve uptake by gastric cancer stem cells (MCSCs). PMNPs, synthesized via thermal decomposition, exhibited a diameter of 90 nm ±â€¯9 nm and a saturation magnetization of 79.9 emu/g. Functionalization enhanced their uptake capabilities. Under a rotating magnetic field (RMF) of 15 Hz, PMNPs disrupted cellular structure, leading to apoptosis and ferroptosis in MCSCs. The in vitro studies showed significant reduction in MCSCs viability, while in vivo studies demonstrated tumor growth suppression with minimal side effects and high biocompatibility. This work presents a novel strategy for designing magnetic nanoparticles to mechanically destroy cancer stem cells, offering a more efficient and safety treatment option for gastric cancer.

Strategies for the Isolation and Identification of Gastric Cancer Stem Cells.

Gastric cancer stem cells (GCSCs) originate from both gastric adult stem cells and bone marrow cells and are conspicuously present within the histological milieu of gastric cancer tissue. GCSCs play pivotal and multifaceted roles in the initiation, progression, and recurrence of gastric cancer. Hence, the characterization of GCSCs not only facilitates precise target identification for prospective therapeutic interventions in gastric cancer but also has significant implications for targeted therapy and the prognosis of gastric cancer. The prevailing techniques for GCSC purification involve their isolation using surface-specific cell markers, such as those identified by flow cytometry and immunomagnetic bead sorting techniques. In addition, in vitro culture and side-population cell sorting are integral methods in this context. This review discusses the surface biomarkers, isolation techniques, and identification methods of GCSCs, as well as their role in the treatment of gastric cancer.

The distribution of heterophilic antigens and their relationship with autoimmune diseases.

Introduction: Microbial infections are associated with the occurrence of autoimmune diseases, but the mechanisms of microbial infection inducing autoimmune diseases are not fully understood. The existence of heterophilic antigens between microorganisms and human tissues may explain part of the pathogenesis of autoimmune diseases. Here, we investigate the distribution of heterophilic antigens and its relationship with autoimmune diseases. Methods: Monoclonal antibodies against a variety of microorganisms were prepared. The titer, subclass and reactivity of antibodies with microorganisms were identified, and heterophilic antibodies that cross-reacted with human tissues were screened by human tissue microarray. The reactivity of these heterophilic antibodies with different individuals and different species was further examined by immunohistochemistry. Results: In this study, 21 strains of heterophilic antibodies were screened. The results showed that these heterophilic antibodies were produced due to the existence of heterophilic antigens between microorganism and human body and the distribution of heterophilic antigens had individual, tissue and species differences. Conclusion: Our study showed that heterophilic antigens exist widely between microorganisms and human body, and the heterophilic antigens carried by microorganisms may break the immune tolerance of the body through carrier effect and initiate immune response, which may be one of the important mechanisms of infection inducing autoimmune diseases.

An effective disease diagnostic model related to pyroptosis in ischemic cardiomyopathy.

Pyroptosis is involved in ischemic cardiomyopathy (ICM). The study aimed to investigate the pyroptosis-related genes and clarify their diagnostic value in ICM. The bioinformatics method identified the differential pyroptosis genes between the normal control and ICM samples from online datasets. Then, protein-protein interaction (PPI) and function analysis were carried out to explore the function of these genes. Following, subtype analysis was performed using ConsensusClusterPlus, functions, immune score, stromal score, immune cell proportion and human leukocyte antigen (HLA) genes between subtypes were investigated. Moreover, optimal pyroptosis genes were selected using the least absolute shrinkage and selection operator (LASSO) analysis to construct a diagnostic model and evaluate its effectiveness using receiver operator characteristic (ROC) analysis. Twenty-one differential expressed pyroptosis genes were identified, and these genes were related to immune and pyroptosis. Subtype analysis identified two obvious subtypes: sub-1 and sub-2. And LASSO identified 13 optimal genes used to construct the diagnostic model. The diagnostic model in ICM diagnosis with the area under ROC (AUC) was 0.965. Our results suggested that pyroptosis was tightly associated with ICM.

Identification of Heterophilic Epitopes of H1N1 Influenza Virus Hemagglutinin.

Our previous studies found that the H1-50 monoclonal antibody (mAb) of influenza A virus hemagglutinin (HA) cross-reacted with pancreatic tissue and islet ß-cells, and further studies showed that H1-50 mAb binds to prohibitin (PHB) protein of islet ß-cells. These suggest that there are heterophilic epitopes between influenza virus HA and pancreatic tissue, which may be involved in the pathogenesis of type 1 diabetes. To further investigate these heterophilic epitopes, we screened binding epitopes of H1-50 mAb using a phage 12-peptide library. DNA sequencing and comparative analysis were performed on specific positive phage clones, and the sequence of 12-peptide binding to H1-50 mAb was obtained. The binding epitopes of H1-50 mAb in influenza virus HA were determined by sequence analysis and experimental verification, and their distribution within the three-dimensional structure was assessed by PyMOL. The results showed that H1-50 mAb specifically binds to polypeptides (306-SLPFQNIHPITIGK-319) of influenza A virus HA, located in the stem of the HA protein. However, there is no specific binding sequence between H1-50 mAb and the PHB protein of islet ß-cells in the primary structure, and we speculate that the binding of H1-50 mAb to islet ß-cells may depend on the spatial conformation. The identification of the heterophilic epitopes of H1N1 influenza virus hemagglutinin provides a new perspective on type 1 diabetes that may be caused by influenza virus infection, which may contribute to the prevention and control of influenza.

An artificialed protein corona coating the surface of magnetic nanoparicles:a simple and efficient method for label antibody.

Background: Protein Corona (PC) of nanoparticles is a structure which composed of one or more layers of proteins adsorbed on the surface of nanomaterials, and the formation of PC is a universal process of spontaneous randomness. We take advantage of the formation principle of the PC, developed a simple and efficient method for label protein to nanoparticles. Methods: The artificialed protein corona (APC) on the surface of nanoparticles was synthesized via the artificialed methods of desolvation aggregation and crosslinking with control. Results: The dosage of precipitator and the ratio of protein to magnetic nanoparticles (MNPs)(particle size: 3 nm) were optimized, and the core-shell nanoparticles with narrow particle size (particle size: 10 nm) distribution were obtained. The MNPs with APC were characterized by transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). Additionally, a hemolysis test on prepared MNPs was conducted with APC. The presence of APC coating on the surface of MNPs showed an improving effect to reduce the cytotoxicity. Cellular toxicity of MNPs with APC was also investigated on HFF1 cell lines. And the cells survival in the presence of APC coated MNPs and display neither reduced metabolism nor cytostatic effect. The functional test of the MNPs with APC showed that proteins can be modified and labeled onto magnetic nanoparticles and retain their original activity. Conclusions: This marking method is gentle and effective. And the properties of the APC propose MNPs as a promising candidate for multifunctional biomedical applications.

Identification and verification of a glycolysis-related gene signature for gastric cancer.

Background: Glycolysis is a central metabolic pathway for tumor cells. However, the relationship between glycolysis and the prognosis of gastric cancer (GC) patients is not well established. In this study, we sought to construct a glycolysis-related gene signature for GC. Methods: The messenger ribonucleic acid (mRNA) expression profiles were analyzed using data from The Cancer Genome Atlas (TCGA) database. Glycolysis-related gene sets and pathways were obtained from the Molecular Signatures Database (MSigDB). Subsequently, a prognosis prediction model of the glycolysis-related genes was constructed using Cox and least absolute shrinkage and selection operator (LASSO) regression analyses. An external validation was conducted using data from the Gene Expression Omnibus (GEO) database. Risk scores were also calculated based on the signature. Finally, the correlations between the risk score and overall survival (OS), mutation, immune cell infiltration, immune score, and stromal score were examined in 22 types of infiltrating immune cells. Results: Fifty-five glycolysis-related genes were identified from TCGA database and MSigDB. Using the LASSO and Cox models, 4 novel genes (i.e., VCAN, EFNA3, ADH4, and CLDN9) were identified to construct a gene signature for GC prognosis prediction. The GC patients with low-risk scores had significantly better OS than those with high-risk scores in the training set. Similar results were also found in the independent GEO GSE84437 testing set. Additionally, the degree of cell infiltration in the low-risk group was significantly higher than that in the high-risk group in terms of naive B cells, plasma cells, and T follicular helper cells. In monocytes, M2 macrophages, resting dendritic cells, and resting Mast cells, the degree of infiltration in the high-risk group was significantly higher than that in the low-risk group. The immune score and stromal score of the high-risk group were also significantly higher than those of the low-risk group. Finally, the univariate and multivariate Cox regression analyses showed that 4 glycolysis-related genes were independent prognostic factors for GC. Conclusions: The established 4 glycolysis-related gene signature may serve as a reliable tool for the prognosis of GC patients and provide a potential glycolysis therapeutic target for GC.

Lipopolysaccharide reduces melanin synthesis in vitiligo melanocytes by regulating autophagy.

Vitiligo is an autoimmune-related disease with a complex aetiology that involves innate immunity. Toll-like receptors (TLRs) are important parts of innate immunity and are related to a variety of autoimmune diseases, including vitiligo, through an unknown mechanism. In this study, we found that the TLR4 gene expression was increased in blood samples of patients with advanced stage vitiligo, and then, we evaluated the effect of TLR4 ligand lipopolysaccharide (LPS) on melanin synthesis in a vitiligo melanocyte cell line PIG3V and along with its mechanism. LPS suppressed melanin synthesis, downregulated the expression of melanin synthesis-related proteins and activated autophagy in vitiligo melanocytes. Inhibiting autophagy with 3-methyladenine or chloroquine blocked these effects. This suggests that LPS inhibits skin pigmentation by modulating autophagy, thus providing novel insights into the pathogenesis of vitiligo.

Syntenin regulates melanogenesis via the p38 MAPK pathway.

Melanogenesis is the synthesis of the skin pigment melanin, which serves a critical role in the study of pigmentary skin diseases. Syntenin has been identified as a melanosome protein, but its role in melanogenesis is not completely understood. The present study aimed to investigate the effects and mechanisms underlying syntenin on melanogenesis in immortalized human melanocytes. Depletion of syntenin expression increased both tyrosinase (Tyr) activity and melanin content. Syntenin silencing also increased the protein expression levels of Tyr, pre­melanosomal protein and microphthalmia­associated transcription factor. In addition, the results indicated that syntenin regulated melanogenesis by upregulating the phosphorylation of p38 mitogen­activated protein kinase (p38 MAPK). Taken together, these findings suggested that the regulation of melanogenesis by syntenin may be mediated by the activation of p38 MAPK and that syntenin might provide new insights into the pathogenesis of pigmented diseases.

Astragaloside III activates TACE/ADAM17-dependent anti-inflammatory and growth factor signaling in endothelial cells in a p38-dependent fashion.

Astragaloside III (AS-III) is a triterpenoid saponin contained in Astragali Radix and has potent anti-inflammatory effects on vascular endothelial cells; however, underlying mechanisms are unclear. In this study, we provided the first piece of evidence that AS-III induced phosphorylation of TNF-α converting enzyme (TACE) at Thr735 and enhanced its sheddase activity. As a result, AS-III reduced surface TNFR1 level and increased content of sTNFR1 in the culture media, leading to the inhibition of NF-κB signaling pathway and attenuation of downstream cytokine gene expression. Furthermore, AS-III induced TACE-dependent epidermal growth factor receptor (EGFR) transactivation and activation of downstream ERK1/2 and AKT pathways. Finally, AS-III induced activation of p38. Both TACE activation and EGFR transactivation induced by AS-III were significantly inhibited by p38 inhibitor SB203580. Taken together, we concluded that AS-III activates TACE-dependent anti-inflammatory and growth factor signaling in vascular endothelial cells in a p38-dependent fashion, which may contribute to its cardiovascular protective effect.

ADAM17 participates in the protective effect of paeoniflorin on mouse brain microvascular endothelial cells.

Paeoniflorin (PF), the most abundant active ingredient of traditional Chinese herbal medicine Paeoniae Radix, has been recognized as a potential neuroprotectant due to its remarkable efficacy on mitigating cerebral infarction and preventing the neurodegenerative diseases. However, the precise mechanisms of PF remain incompletely understood. In this study, we first provided evidence for the protective effect of PF on hydrogen peroxide-induced injury on mouse brain microvascular endothelial bEnd.3 cells, and for transactivation of the epidermal growth factor receptor (EGFR) signal induced by PF, suggesting that EGFR transactivation might be involved in the beneficial role of PF. Next, by detecting the phosphorylation of a disintegrin and metalloprotease 17 (ADAM17) at Thr 735 and performing loss-of-function experiments with the ADAM17 inhibitor and ADAM 17-siRNA, we showed that PF-induced transactivation of EGFR and downstream ERKs and AKT signaling pathways were dependent on ADAM17. Furthermore, PF-induced phosphorylation of ADAM17 and the EGFR transactivation were inhibited by the inhibitors of adenosine A1 receptor (A1R) or Src kinase that were applied to cells prior to PF treatment, implying the involvement of A1R, and Src in the activation of ADAM17. Finally, PF reduced the cell surface level of TNF-receptor 1 (TNFR1) and increased the content of soluble TNFR1 (sTNFR1) in the culture media, indicating that PF might enhance the shedding of sTNFR1. Taken together, we conclude that A1R and Src-dependent activation of ADAM17 participates in PF-induced EGFR transactivation and TNFR1 shedding on mouse brain microvascular endothelial cells, which may contributes to the neuroprotective effects of PF.

Antibodies against H1N1 influenza virus cross-react with α-cells of pancreatic islets.

Epidemiological studies have documented that the incidence of human type 1 diabetes was significantly increased after H1N1 epidemic. However, a direct link between human type 1 diabetes and virus infection remains elusive. We generated 84 clones of murine monoclonal antibodies against the H1N1, and carried out immunohistochemistry in normal human tissue microarray. The results showed that two clones specifically cross-reacted with human α-cells of pancreatic islets. Reverse transcription polymerase chain reaction and deoxyribonucleic acid sequencing showed that the amino acid sequences of light and heavy chains of these clones were different. Importantly, the expression profiles of two monoclonal antibodies were individual different. For the first time, we provide direct evidence that monoclonal antibodies against H1N1 can cross-react with human pancreas α-cells, another source of ß-cells, suggesting α-cells might be a novel target to be investigated in diabetes research.

[Toll-like receptor 4 activation inhibits melanogenesis in melanocytes].

Objective To explore the effect of Toll-like receptor 4 (TLR4) activation on melanogenesis in melanocytes. Methods The primary melanocytes were isolated, cultured and then stimulated by TLR4 agonist lipopolysaccharide (LPS). Firstly, the melanin content changes were detected in melanocytes, and then quantitative real-time PCR and Western blotting were employed to determine the expression levels of pre-melanosomal protein (Pmel17), tyrosinase (TYR) and microphthalmia-associated transcription factor (MITF). Finally, the melanosomes were observed by electron microscopy. Results After stimulated by LPS, melanin formation in melanocytes was significantly reduced. The expressions of Pmel17 and TYR were markedly suppressed, which depended on the regulation of transcription factor MITF. The electron microscopy showed that melanosome synthesis was inhibited. Conclusion TLR4 activation reduces melanin synthesis in melanocytes, which indicates that the bacterial products may affect melanin synthesis through innate immunity.

[Inhibition of Paeoniflorin on TNF-α-induced TNF-α Receptor Type I /Nuclear Factor-κB Signal Transduction in Endothelial Cells].

OBJECTIVE: To study the inhibitory effect of paeoniflorin (PAE) on TNF-α-induced TNF receptor type I (TNFR1)-mediated signaling pathway in mouse renal arterial endothelial cells (AECs) and to explore its underlying molecular mechanisms. METHODS: Mouse AECs were cultured in vitro and then they were treated by different concentrations PAE or TNF-α for various time periods. Expression levels of intercellular cell adhesion molecule-1 (ICAM-1) were detected in the normal group (cultured by serum-free culture media), the TNF-α group (cultured by 2-h serum-free culture media plus 6-h TNF-α 30 ng/mL), the low dose PAE group (cultured by 2-h PAE 0.8 µmo/L plus 6-h TNF-α 30 ng/mL), the middle dose PAE group (cultured by 2-h PAE 8 µmol/L plus 6-h TNF-α 30 ng/mL), the high dose PAE group (cultured by 2-h PAE 80 µmol/L plus 6-h TNF-α 30 ng/mL) with Western blot analysis. Nuclear translocation of transcription factor NF-κB (NE-κB) was detected in the normal group (cultured by serum-free culture media), the TNF-α group (cultured by 2-h serum-free culture media plus 45-mm TNF-α 30 ng/mL), and the high dose PAE group (cultured by 2-h PAE 80 µmol/L plus 45-min TNF-α 30 ng/mL) by immunofluorescent staining. Expression levels of the phosphorylation of extracellular signal-regulated (protein) kinase (ph-ERK) and p38 (ph- p38) were detected in the normal group (cultured by serum-free culture media) and the high dose PAE group (2-h PAE 80 µmol/L culture) by Western blot. NF-κB inhibitor-α (IκBα) protein expressions were detected in the normal group (cultured by serum-free culture media), the TNF-α group (cultured by 2-h serum-free culture media plus 30-min TNF-α 30 ng/mL), the high dose PAE group (cultured by 2-h PAE 80 µmol/L plus 30-min TNF-α 30 ng/mL), the p38 inhibitor group (SB group, pretreatment with SB238025 25 µmol/L for 30 min, then treated by PAE 80 µmol/L for 2 h, and finally treated by TNF-α 30 ng/mL for 30 min), the ERK inhibitor group (PD group, treated by PD98059 50 µmol/L for 30 min, then treated by PAE 80 µmol/L for 2 h, and finally treated by TNF-α 30 ng/mL for 30 min) by Western blot. RESULTS: Compared with the normal group, ICAM-1 protein expression levels obviously increased (P < 0.01). Compared with the TNFα group, ICAM-1 protein expression levels were obviously inhibited in the high dose PAE group (P < 0.05). Protein expression levels of ph-p38 and ph-ERK were obviously higher in the hIgh dose PAE group (P < 0.05). Compared with the normal group, IκBα protein expression levels obviously decreased in the TNF-α group (P < 0.01). Compared with the TNFα group, TNF-α-induced IκBα degradation could be significantly inhibited in the high dose PAE group (P < 0.01); the inhibition of PAE on IκBα degradation could be significantly inhibited in the SB group (P < 0.05). NF-κB/p65 signal was mainly located in cytoplasm in the normal group. NF-κB/p65 was translocated from cytoplasm to nucleus after stimulated by 45 min TNF-α in the TNF-α group, while it could be significantly inhibited in the high dose PAE group. CONCLUSIONS: PAE inhibited TNF-α-induced expression of lCAM-1. Its action might be associated with inhibiting TNFR1/NF-κB signaling pathway. p38 participated and mediated these actions.

Hydroxy-Safflower Yellow A inhibits the TNFR1-Mediated Classical NF-κB Pathway by Inducing Shedding of TNFR1.

Hydroxy-safflower yellow A (HSYA) is the major active component of safflower, a traditional Asia herbal medicine well known for its cardiovascular protective activities. The purpose of this study was to investigate the effect of HSYA on TNF-α-induced inflammatory responses in arterial endothelial cells (AECs) and to explore the mechanisms involved. The results showed that HSYA suppressed the up-regulation of ICAM-1 expression in TNF-α-stimulated AECs in a dose-dependent manner. High concentration (120 µM) HSYA significantly inhibited the TNF-α-induced adhesion of RAW264.7 cells to AECs. HSYA blocked the TNFR1-mediated phosphorylation and degradation of IκBα and also prevented the nuclear translocation of NF-κB p65. Moreover, HSYA reduced the cell surface level of TNFR1 and increased the content of sTNFR1 in the culture media. TNF-α processing inhibitor-0 (TAPI-0) prevented the HSYA inhibition of TNFR1-induced IκBα degradation, implying the occurrence of TNFR1 shedding. Furthermore, HSYA induced phosphorylation of TNF-α converting enzyme (TACE) at threonine 735, which is thought to be required for its activation. Conclusively, HSYA suppressed TNF-α-induced inflammatory responses in AECs, at least in part by inhibiting the TNFR1-mediated classical NF-κB pathway. TACE-mediated TNFR1 shedding can be involved in this effect. Our study provides new evidence for the antiinflammatory and anti-atherosclerotic effects of HSYA. Copyright © 2016 John Wiley & Sons, Ltd.

Development and characterization of a panel of cross-reactive monoclonal antibodies generated using H1N1 influenza virus.

To characterize the antigenic epitopes of the hemagglutinin (HA) protein of H1N1 influenza virus, a panel consisting of 84 clones of murine monoclonal antibodies (mAbs) were generated using the HA proteins from the 2009 pandemic H1N1 vaccine lysate and the seasonal influenza H1N1(A1) vaccines. Thirty-three (39%) of the 84 mAbs were found to be strain-specific, and 6 (7%) of the 84 mAbs were subtype-specific. Twenty (24%) of the 84 mAbs recognized the common HA epitopes shared by 2009 pandemic H1N1, seasonal A1 (H1N1), and A3 (H3N2) influenza viruses. Twenty-five of the 84 clones recognized the common HA epitopes shared by the 2009 pandemic H1N1, seasonal A1 (H1N1) and A3 (H3N2) human influenza viruses, and H5N1 and H9N2 avian influenza viruses. We found that of the 16 (19%) clones of the 84 mAbs panel that were cross-reactive with human respiratory pathogens, 15 were made using the HA of the seasonal A1 (H1N1) virus and 1 was made using the HA of the 2009 pandemic H1N1 influenza virus. Immunohistochemical analysis of the tissue microarray (TMA) showed that 4 of the 84 mAb clones cross-reacted with human tissue (brain and pancreas). Our results indicated that the influenza virus HA antigenic epitopes not only induce type-, subtype-, and strain-specific monoclonal antibodies against influenza A virus but also cross-reactive monoclonal antibodies against human tissues. Further investigations of these cross-reactive (heterophilic) epitopes may significantly improve our understanding of viral antigenic variation, epidemics, pathophysiologic mechanisms, and adverse effects of influenza vaccines.

A comparative study on inhibition of total astragalus saponins and astragaloside IV on TNFR1-mediated signaling pathways in arterial endothelial cells.

BACKGROUND: Both total astragalus saponins (AST) and it's main component astragaloside IV (ASIV) have been used in China as cardiovascular protective medicines. However, the anti-inflammatory activities that are beneficial for cardiovascular health have never been compared directly and the molecular mechanisms remain unresolved. This study was conducted to compare the inhibitory effects of these drugs on TNFα-induced cell responses, related signaling pathways, and the underlying mechanisms in mouse arterial endothelial cells. METHODOLOGY/PRINCIPAL FINDINGS: Real-time qRT-PCR was performed to determine the expression of cell adhesion molecule (CAM) genes. Immunofluorescent staining was used to detect the nuclear translocation of transcription factor NF-κB-p65. Western Blot analysis was used to identify TNFα-induced NF-κB-p65 phosphorylation, IκBα degradation, and caspase-3 cleavage. Cell surface proteins were isolated and TNFα receptor-1(TNFR1) expression was determined. The results suggest that both AST and ASIV attenuate TNFα-induced up-regulation of CAMs mRNA and upstream nuclear translocation and phosphorylation of NF-κB-p65. However, TNFR1-mediated IκBα degradation, cleavage of caspase-3 and apoptosis were inhibited only by AST. These differences in the actions of AST and ASIV could be explained by the presence of other components in AST, such as ASII and ASIII, which also had an inhibitory effect on TNFR1-induced IκBα degradation. Moreover, AST, but not ASIV, was able to reduce TNFR1 protein level on the cell surface. Furthermore, mechanistic investigation demonstrated that TNFR1-mediated IκBα degradation was reversed by the use of TAPI-0, an inhibitor of TNFα converting enzyme (TACE), suggesting the involvement of TACE in the modulation of surface TNFR1 level by AST. CONCLUSION: ASIV was not a better inhibitor than AST, at least on the inhibition of TNFα-induced inflammatory responses and TNFR1-mediated signaling pathways in AECs. The inhibitory effect of AST was caused by the reduction of cell surface TNFR1 level, and TACE could be involved in this action.