Role of lipocortin I in the glucocorticoid induction of the terminal differentiation of a human squamous carcinoma

Breast cancer metastasis to brain results in recruitment and activation of microglia through annexin-A1/formyl peptide receptor signaling

Background

Despite advancements in therapies, brain metastasis in patients with triple negative subtype of breast cancer remains a therapeutic challenge. Activated microglia are often observed in close proximity to, or within, malignant tumor masses, suggesting a critical role that microglia play in brain tumor progression. Annexin-A1 (ANXA1), a glucocorticoid-regulated protein with immune-regulatory properties, has been implicated in the growth and metastasis of many cancers. Its role in breast cancer-microglia signaling crosstalk is not known.

Methods

The importance of microglia proliferation and activation in breast cancer to brain metastasis was evaluated in MMTV-Wnt1 spontaneous mammary tumor mice and BALBc mice injected with 4T1 murine breast cancer cells into the carotid artery using flow cytometry. 4T1 induced-proliferation and migration of primary microglia and BV2 microglia cells were evaluated using 2D and coculture transwell assays. The requirement of ANXA1 in these functions was examined using a Crispr/Cas9 deletion mutant of ANXA1 in 4T1 breast cancer cells as well as BV2 microglia. Small molecule inhibition of the ANXA1 receptor FPR1 and FPR2 were also examined. The signaling pathways involved in these interactions were assessed using western blotting. The association between lymph node positive recurrence-free patient survival and distant metastasis-free patient survival and ANXA1 and FPR1 and FPR2 expression was examined using TCGA datasets.

Results

Microglia activation is observed prior to brain metastasis in MMTV-Wnt1 mice with primary and secondary metastasis in the periphery. Metastatic 4T1 mammary cancer cells secrete ANXA1 to promote microglial migration, which in turn, enhances tumor cell migration. Silencing of ANXA1 in 4T1 cells by Crispr/Cas9 deletion, or using inhibitors of FPR1 or FPR2 inhibits microglia migration and leads to reduced activation of STAT3. Finally, elevated ANXA1, FPR1 and FPR2 is significantly associated with poor outcome in lymph node positive patients, particularly, for distant metastasis free patient survival.

Conclusions

The present study uncovered a network encompassing autocrine/paracrine ANXA1 signaling between metastatic mammary cancer cells and microglia that drives microglial recruitment and activation. Inhibition of ANXA1 and/or its receptor may be therapeutically rewarding in the treatment of breast cancer and secondary metastasis to the brain.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13058-022-01514-2.

Annexin A1 Expression in Nasopharyngeal Carcinoma Correlates with Squamous Differentiation

Background

Alterations of annexin A1 (ANXA1) expression have been reported in various cancers. However, no data are available about the expression of this protein in nasopharyngeal carcinomas (NPCs). The objective of this study was to investigate the expression of ANXA1 in these tumors.

Methods

We examined noncancerous nasopharyngeal mucosa (4 cases) and NPC (20 cases) for ANXA1 expression using immunohistochemistry.

Results

All tumor tissues showed markedly reduced ANXA1 expression compared with a strong positive signal observed in the corresponding normal epithelia. We found that ANXA1 expression is associated with the histological type in NPC. Only squamous cell carcinomas presented a positive ANXA1 signal in differentiated areas whereas all poorly differentiated tumors exhibited negative staining.

Conclusion

Our data show for the first time that ANXA1 expression is down-regulated in NPC and that its expression seems to be related with the squamous differentiation status of these tumors.

Annexin A1 is elevated in patients with COPD and affects lung fibroblast function

Purpose

Fibrosis in peripheral airways is responsible for airflow limitation in chronic obstructive pulmonary disease (COPD). Annexin A1 modulates several key biological events during inflammation. However, little is known about its role in airway fibrosis in COPD. We investigated whether levels of Annexin A1 were upregulated in patients with COPD, and whether it promoted airway fibrosis.

Methods

We quantified serum Annexin A1 levels in never-smokers (n=12), smokers without COPD (n=11), and smokers with COPD (n=22). Correlations between Annexin A1 expression and clinical indicators (eg, lung function) were assessed. In vitro, human bronchial epithelial (HBE) cells were exposed to cigarette smoke extract (CSE) and Annexin A1 expression was assessed. Primary human lung fibroblasts were isolated from patients with COPD and effects of Annexin A1 on fibrotic deposition of lung fibroblasts were evaluated.

Results

Serum Annexin A1 was significantly higher in patients with Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines stage III or IV than in those with GOLD stages I or II (12.8±0.8 ng/mL versus 9.8±0.7 ng/mL; p=0.016). Annexin A1 expression was negatively associated with airflow obstruction (forced expiratory volume in one second % predicted; r=−0.72, p<0.001). In vitro, Annexin A1 was significantly increased in CSE-exposed HBE cells in a time- and concentration-dependent manner. Annexin A1 promoted lung fibroblasts proliferation, migration, differentiation, and collagen deposition via the ERK1/2 and p38 mitogen-activated protein kinase pathways.

Conclusion

Annexin A1 expression is upregulated in patients with COPD and affects lung fibroblast function. However, more studies are needed to clarify the role of Annexin A1 in airway fibrosis of COPD.

Multiplicity of Glucocorticoid Action in Inhibiting Allograft Rejection

Glucocorticoids (GCs) are used as immunosuppressive and antiinflammatory agents in organ transplantation and in treating autoimmune diseases and inflammatory disorders. GCs were shown to exert their antiproliferative effects directly through blockade of certain elements of an early membrane-associated signal transduction pathway, modulation of the expression of select adhesion molecules, and by suppression of cytokine synthesis and action. GCs may act indirectly by inducing lipocortin synthesis, which in turn, inhibits arachidonic acid release from membrane-bound stores, and also by inducing transforming growth factor (TGF)-β expression that subsequently blocks cytokine synthesis and T cell activation. Furthermore, by preferentially inhibiting the production of Th1 cytokines, GCs may enhance Th2 cell activity and, hence, precipitate a long-lasting state of tolerance through a preferential promotion of a Th2 cytokine-secreting profile. In exerting their antiproliferative effects, GCs influence both transcriptional and posttranscriptional events by binding their cytosolic receptor (GR), which subsequently binds the promoter region of cytokine genes on select DNA sites compatible with the GCs responsible elements (GRE) motif. In addition to direct DNA binding, GCs may also directly bind to, and hence antagonize, nuclear factors required for efficient gene expression, thereby markedly reducing transcriptional rate. The pleiotrophy of the GCs action, coupled with the diverse experimental conditions employed in assessing the GCs effects, indicate that GCs may utilize more than one mechanism in inhibiting T cell activation, and warrant careful scrutiny in assigning a mechanism by which GCs exert their antiproliferative effects. © 1998 Elsevier Science Inc.

Study of the Annexin A1 and Its Associations with Carcinoembryonic Antigen and Mismatch Repair Proteins in Colorectal Cancer

PURPOSE

Annexin-A1 (ANXA1) has been implicated in various tumor types, but few studies have investigated its involvement in colorectal cancer. The study aimed to analyze ANXA1 expression in the normal margin and colorectal tumor tissues of 104 patients who underwent surgery for colorectal cancer and to associate the ANXA1 expression with predictive clinicopathological variables.

METHODS

Hematoxylin-eosin and immunohistochemical staining were used for the analysis.

RESULTS

ANXA1 expression was higher in colorectal cancer than in normal margin tissue (p = 0.0001). However, no differences were observed when we analyzed the ANXA1 expression in colon and rectal tumors (p = 0.830). Also, this protein positivity was associated with increased carcinoembryonic antigen levels (p = 0.004). Our data in the DNA-mismatch repair proteins expression was in accordance to the literature. And their positivity was not associated with ANXA1 presence in colorectal cancer.

CONCLUSION

The high incidence of ANXA1 positive expression in colorectal cancer and its association with carcinoembryonic antigen levels might indicate the importance of this protein in the colorectal cancer biology.

A mass spectrometric insight into the origins of benign gynecological disorders

Applications of mass spectrometry (MS) are rapidly expanding and encompass molecular and cellular biology. MS aids in the analysis of in vivo global molecular alterations, identifying potential biomarkers which may improve diagnosis and treatment of various pathologies. MS has added new dimensionality to medical research. Pioneering gynecologists now study molecular mechanisms underlying female reproductive pathology with MS-based tools. Although benign gynecologic disorders including endometriosis, adenomyosis, leiomyoma, and polycystic ovarian syndrome (PCOS) carry low mortality rates, they cause significant physical, mental, and social detriments. Additionally, some benign disorders are unfortunately associated with malignancies. MS-based technology can detect malignant changes in formerly benign proteomes and metabolomes with distinct advantages of speed, sensitivity, and specificity. We present the use of MS in proteomics and metabolomics, and summarize the current understanding of the molecular pathways concerning female reproductive anatomy. Highlight discoveries of novel protein and metabolite biomarkers via MS-based technology, we underscore the clinical application of these techniques in the diagnosis and management of benign gynecological disorders. © 2015 Wiley Periodicals, Inc. Mass Spec Rev 36:450-470, 2017.

ANXA1Ac₂₋₂₆ peptide reduces ID1 expression in cervical carcinoma cultures

Cervical cancer is the second most frequent cancer in women worldwide and is associated with genetic alterations, infection with human papilloma virus (HPV), angiogenesis and inflammatory processes. The idea that inflammation is involved in tumorigenesis is supported by the frequent appearance of cancer in areas of chronic inflammation. On the other hand, the inflammatory response is controlled by the action of anti-inflammatory mediators, among these mediators, annexin A1 (ANXA1), a 37 kDa protein was detected as a modulator of inflammatory processes and is expressed by tumor cells. The study was carried out on the epithelial cancer cell line (SiHa) treated with the peptide of annexin A1 (ANXA1Ac2-26). We combined subtraction hybridization approach, Ingenuity Systems software and quantitative PCR, in order to evaluate gene expression influenced by ANXA1. We observed that ANXA1Ac2-26 inhibited proliferation in SiHa cells after 72h. In these cells, 55 genes exhibited changes in expression levels in response to peptide treatment. Six genes were selected and the expression results of 5 up-regulated genes (TPT1, LDHA, NCOA3, HIF1A, RAB13) and one down-regulated gene (ID1) were research by real time quantitative PCR. Four more genes (BMP4, BMPR1B, SMAD1 and SMAD4) of the ID1 pathway were investigated and only one (BMPR1B) shows the same down regulation. The data indicate the involvement of ANXA1Ac2-26 in the altered expression of genes involved in tumorigenic processes, which could potentially be applied as a therapeutic indicator of cervical cancer.

Selectivity of cytosolic phospholipase A2 type IV toward arachidonyl phospholipids

Cytosolic phospholipase A2 (cPLA2 ) is an interesting protein involved in inflammatory processes and various diseases. Its catalytic mechanism as well as its substrate specificity for arachidonyl phospholipids is not typical for other phospolipases. Furthermore, a lid structure, which ensures a hydrophilic surface of the protein without any substrate bound and the movement of this flexible loop to make the hydrophobic active site accessible, is of high interest. Therefore, the focus of this work was to determine the binding mode of cPLA2 with various substrates, such as arachidonic acid, a synthetic inhibitor, a saturated phospholipid, and most importantly an arachidonyl phospholipid. To understand the selectivity of the protein toward the arachidonyl phospholipid and the interaction in a protein-ligand complex, molecular dynamics simulations were performed using the GROMOS suite of simulation programs. The simulations provide insight into the protein and showed that selective binding of arachidonyl phospholipids is because of the shape of the sn-2 tail. The amino acids Asn555 and Ala578 are involved in the strongest interactions observed in the protein-ligand complexes.

Annexin A10 is an immunohistochemical marker for adenocarcinoma of the upper gastrointestinal tract and pancreatobiliary system

AIMS

Annexin A10 (ANXA10) is a calcium- and phospholipid-binding protein expressed normally in the gastric mucosa. In this study, we evaluated the potential use of ANXA10 as a diagnostic marker.

METHODS AND RESULTS

We observed ANXA10 expression in the gastric mucosa, the Brunner gland of the duodenum and the urothelium, but absence of expression in other normal organs. Following the screening of 1327 primary carcinomas of major organs, we identified ANXA10 expression in 46% of gastric, 72% of ampullary, 78% of pancreatic and 33% of biliary adenocarcinomas. ANXA10 was expressed in 83% of non-invasive urothelial carcinomas, but was expressed in only 9% of invasive urothelial carcinomas. ANAX10 was rarely expressed in carcinomas of other organs. Of 227 metastatic adenocarcinomas, ANXA10 was expressed in 83% of metastatic pancreatic and 47% of metastatic gastric adenocarcinomas, but was expressed in only 2% of metastatic adenocarcinomas from other organs. In the liver, the sensitivity and specificity for identifying the pancreas as the primary site of metastatic adenocarcinoma were 83 and 95%, respectively.

CONCLUSION

Our study results indicate that the inclusion of ANXA10 in an immunohistochemical panel will be helpful in the differential diagnosis of adenocarcinoma of an unknown primary site.

Annexin A1: potential for glucocorticoid sparing in RA

Glucocorticoids have broad-ranging and powerful anti-inflammatory and immunomodulatory effects. Unsurprisingly, therefore, glucocorticoids are widely and persistently used to treat a large number of inflammatory diseases, including rheumatoid arthritis (RA), despite the well-described adverse effects of these drugs. Annexin A1 is a glucocorticoid-induced molecule that is known to replicate many of the described anti-inflammatory effects of glucocorticoids. In addition to the well-documented roles of this protein in neutrophil function, emerging evidence suggests that annexin A1 is involved in the modulation of T-cell function and the adaptive immune responses relevant to RA. Interest in annexin A1 was renewed after the delineation of the receptors for this protein. This breakthrough also led to advances in our understanding of anti-inflammatory annexin A1 mimetic peptides and agonistic compounds targeting these receptors, particularly those specific for the receptor N-formyl peptide receptor 2 (FPR2). Herein, we review the current knowledge of the biological activities of annexin A1 and their relevance to RA pathogenesis. We also discuss the potential of annexin A1 mimics and strategies aimed at potentiating annexin A1 signalling to become viable approaches to minimizing glucocorticoid use in RA and other inflammatory disorders.

Propofol inhibits the activation of p38 through up-regulating the expression of annexin A1 to exert its anti-inflammation effect

Inflammatory response is a kind of nonspecific immune response, with the central link of vascular response, which is mainly manifested by changes in neutrophils and vascular endothelial cells. In recent years, the in vivo and in vitro role of intravenous anesthetic propofol in inhibiting inflammatory response has been attracting more and more attention, but the anti-inflammatory mechanisms of propofol for mononuclear cells still remain undefined. In this study, proteomics analysis was applied to investigate protein expression profile changes in serum mononuclear cells following intervention of rats with endotoxemia using propofol. After two-dimensional electrophoresis and mass spectrometric identification, it has been found that the protein Annexin A1 was up-regulated in the propofol intervention group. Annexin A1 is a glucocorticoid-dependent anti-inflammatory protein. After detection using ELISA and Western blot assays, it has also been found that propofol can not only promote the expression of Annexin A1, but also inhibit the phosphorylation level of p38 and release of inflammatory factors (IL-1β, IL-6 and TNF-α) in rats with endotoxemia. In order to further determine the role of up-regulated expression of Annexin A1 in anti-inflammation of propofol, this gene was silenced in vitro in human THP-1 cells, to detect the phosphorylation status of p38 and release of inflammatory factors. The results show that Annexin A1 can negatively regulate phosphorylation of p38 and release of IL-1β, IL-6 and TNF-α in THP-1 cells following propofol intervention and lipopolysaccharide (LPS) stimulation. Our results clearly indicate that propofol can up-regulate Annexin A1 to inhibit the phosphorylation level of p38 and release of IL-1β, IL-6 and TNF-α, so as to inhibit inflammatory response. Therefore, it can be speculated that Annexin A1 might be the key signaling protein in the in vivo and in vitro anti-inflammatory mechanisms of propofol.

Endogenous annexin A1 counter-regulates bleomycin-induced lung fibrosis

Background

The balancing functions of pro/anti-inflammatory mediators of the complex innate responses have been investigated in a variety of experimental inflammatory settings. Annexin-A1 (AnxA1) is one mediator of endogenous anti-inflammation, affording regulation of leukocyte trafficking and activation in many contexts, yet its role in lung pathologies has been scarcely investigated, despite being highly expressed in lung cells. Here we have applied the bleomycin lung fibrosis model to AnxA1 null mice over a 21-day time-course, to monitor potential impact of this mediator on the control of the inflammatory and fibrotic phases.

Results

Analyses in wild-type mice revealed strict spatial and temporal regulation of the Anxa1 gene, e.g. up-regulation in epithelial cells and infiltrated granulocytes at day 7, followed by augmented protein levels in alveolar macrophages by day 21. Absence of AnxA1 caused increases in: i) the degree of inflammation at day 7; and ii) indexes of fibrosis (assessed by deposition of hydroxyproline in the lung) at day 7 and 21. These alterations in AnxA1 null mice were paralleled by augmented TGF-β1, IFN-γ and TNF-α generation compared to wild-type mice. Finally, treatment of wild type animals with an AnxA1 peptido-mimetic, given prophylactically (from day 0 to 21) or therapeutically (from day 14 onward), ameliorated both signs of inflammation and fibrosis.

Conclusion

Collectively these data reveal a pathophysiological relevance for endogenous AnxA1 in lung inflammation and, more importantly, fibrosis, and may open new insights for the pharmacological treatment of lung fibrosis.

Expression and prognostic significance of gastric-specific annexin A10 in diffuse- and intestinal-type gastric carcinoma

BACKGROUND AND AIMS

Annexin A10 (ANXA10) and its liver-specific short isoform (ANXA10S) had tissue-restricted expression. The downregulation of ANXA10S is correlated with tumor progression and poor prognosis in hepatocellular carcinoma. The aim of the present study was to validate the tissue distribution and explore the role of the ANXA10 protein expression in gastric carcinoma.

METHODS

We examined the ANXA10 protein expression in human and animal tissues and 356 resected primary gastric carcinomas, using specific mouse and rabbit polyclonal antibodies, by immunohistochemical staining.

RESULTS

The ANXA10 protein is a nuclear protein specifically expressed in fetal and adult gastric mucosa and Brunner's gland across species, including humans, minipigs, woodchucks, and mice, and is commonly lost in gastric mucosa with intestinal metaplasia. The ANXA10 protein was expressed in 43.5% (155 cases) of gastric carcinomas; 74.2% (98/132) in the diffuse-type gastric carcinoma (DGC), 73.7% (28/38) in the mixed-type gastric carcinoma, and significantly lower in the intestinal-type gastric carcinoma (IGC) and indeterminate groups, 16.8% (28/167) and 5.3% (1/19), respectively (P<1×10(-8)). IGC with ANXA10 expression was correlated with a higher stage (P=0.049), particularly higher in stage IIIA/IIIB/IV IGC than lower-stage (IA/IB/II) tumors (P=0.005), but was not correlated with age, sex, and nodal status. In contrast, DGC with ANXA10 expression was associated with younger age, female patients, and importantly, lower tumor stage and lymph node metastasis (P=0.007, P=0.065, P=0.024, and P=0.0014, respectively). Moreover, DGC with ANXA10 expression had a better 5-year patient survival (P=0.0048), whereas IGC with ANXA10 expression had a lower 5-year survival (P=0.034).

CONCLUSIONS

The ANXA10 protein expression is a novel marker of gastric differentiation, and is differentially expressed in IGC and DGC, with opposite prognostic significance.

Proteomic profiling of rat lung epithelial cells induced by acrolein

AIMS

Acrolein is a highly toxic unsaturated aldehyde and is also an endogenous byproduct produced from lipid peroxidation. It can be formed from the breakdown of certain pollutants in outdoor air or from burning tobacco or gasoline. Inhalation and dermal exposure to acrolein are extremely toxic to human tissue. Although it is known that acrolein is toxic to lung tissue, no studies have attempted to address the changes induced by acrolein on a global scale.

MAIN METHODS

In the present study we have attempted to address the changes in global protein expression induced by acrolein using proteomics analysis in rat lung epithelial cells.

KEY FINDINGS

Our analysis reveals a comprehensive profiling of the proteins that includes a heterogeneous class of proteins and this compels one to consider that the toxic response to acrolein is very complex. There were 34 proteins that showed changes between the control cells and after acrolein treatment. The expression of 18 proteins was increased and the expression of 16 proteins was decreased following exposure to acrolein. We have further validated two differentially expressed proteins namely annexin II (ANXII) and prohibitin (PHB) in lung epithelial cells treated with acrolein.

SIGNIFICANCE

Based on the results of the overall proteomic analysis, acrolein appears to induce changes in a diverse range of proteins suggesting a complex mechanism of acrolein-induced toxicity in lung epithelial cells.

Annexin A1 subcellular expression in laryngeal squamous cell carcinoma

AIMS

Annexin A1 (ANXA1) is a soluble cytoplasmic protein, moving to membranes when calcium levels are elevated. ANXA1 has also been shown to move to the nucleus or outside the cells, depending on tyrosine-kinase signalling, thus interfering in cytoskeletal organization and cell differentiation, mostly in inflammatory and neoplastic processes. The aim was to investigate subcellular patterns of immunohistochemical expression of ANXA1 in neoplastic and non-neoplastic samples from patients with laryngeal squamous cell carcinomas (LSCC), to elucidate the role of ANXA1 in laryngeal carcinogenesis.

METHODS AND RESULTS

Serial analysis of gene expression experiments detected reduced expression of ANXA1 gene in LSCC compared with the corresponding non-neoplastic margins. Quantitative polymerase chain reaction confirmed ANXA1 low expression in 15 LSCC and eight matched normal samples. Thus, we investigated subcellular patterns of immunohistochemical expression of ANXA1 in 241 paraffin-embedded samples from 95 patients with LSCC. The results showed ANXA1 down-regulation in dysplastic, tumourous and metastatic lesions and provided evidence for the progressive migration of ANXA1 from the nucleus towards the membrane during laryngeal tumorigenesis.

CONCLUSIONS

ANXA1 dysregulation was observed early in laryngeal carcinogenesis, in intra-epithelial neoplasms; it was not found related to prognostic parameters, such as nodal metastases.

Down-regulation of plasma membranous Annexin A1 protein expression in premalignant and malignant lesions of the oral cavity: correlation with epithelial differentiation

PURPOSE

To determine the potential involvement of ANXA1 in oral squamous-cell carcinoma (OSCC), we evaluated the ANXA1 protein expression in oral premalignant lesions (OPLs) and OSCCs and correlated the results with clinicopathologic variables.

METHODS

Matched normal and tumour specimens of 44 primary OSCCs and 28 OPLs were analyzed for ANXA1 subcellular localization and protein expression level by immunohistochemistry (IHC). Correlations between ANXA1-IHC staining scores of OSCCs and clinicopathologic features were evaluated by Fisher's exact test.

RESULTS

Markedly down-regulation of ANXA1 protein expression was identified on the plasma membrane of epithelial cells in OSCCs (P < 0.001) and OPLs (P = 0.001) compared with normal counterparts. Moreover, loss of plasma membranous ANXA1 expression was significantly correlated with the poorly differentiated status of OSCC cells (P = 0.012).

CONCLUSIONS

Our findings suggest that loss of ANXA1 is frequent and early event during oral carcinogenesis and that ANXA1 could contribute to maintaining epithelial differentiation in OSCC.

Annexin A1 regulates intestinal mucosal injury, inflammation, and repair

During mucosal inflammation, a complex array of proinflammatory and protective mechanisms regulates inflammation and severity of injury. Secretion of anti-inflammatory mediators is a mechanism that is critical in controlling inflammatory responses and promoting epithelial restitution and barrier recovery. AnxA1 is a potent anti-inflammatory protein that has been implicated to play a critical immune regulatory role in models of inflammation. Although AnxA1 has been shown to be secreted in intestinal mucosal tissues during inflammation, its potential role in modulating the injury/inflammatory response is not understood. In this study, we demonstrate that AnxA1-deficient animals exhibit increased susceptibility to dextran sulfate sodium (DSS)-induced colitis with greater clinical morbidity and histopathologic mucosal injury. Furthermore, impaired recovery following withdrawal of DSS administration was observed in AnxA1 (-/-) animals compared with wild-type (WT) control mice that was independent of inflammatory cell infiltration. Since AnxA1 exerts its anti-inflammatory properties through stimulation of ALX/FPRL-1, we explored the role of this receptor-ligand interaction in regulating DSS-induced colitis. Interestingly, treatment with an ALX/FPRL-1 agonist, 15-epi-lipoxin A4 reversed the enhanced sensitivity of AnxA1 (-/-) mice to DSS colitis. In contrast, 15-epi-lipoxin A4 did not significantly improve the severity of disease in WT animals. Additionally, differential expression of ALX/FPLR-1 in control and DSS-treated WT and AnxA1-deficient animals suggested a potential role for AnxA1 in regulating ALX/FPRL-1 expression under pathophysiological conditions. Together, these results support a role of endogenous AnxA1 in the protective and reparative properties of the intestinal mucosal epithelium.

Decreased expression of annexin A1 during the progression of cervical neoplasia

The aim of this study was to evaluate whether the expression of annexin A1 (ANXA1) is associated with the progression of cervical neoplasia. ANXA1 expression was examined by immunohistochemistry in paraffin-embedded cervical tissue samples (n = 234), comprising 52 samples of normal cervical epithelia, 30 of cervical intraepithelial neoplasia (CIN) I, 27 of CIN II, 32 of CIN III, and 93 of invasive squamous cell carcinoma (ISCC). ANXA1 expression was strong in normal cervical squamous epithelium and significantly reduced with increasing progression of cervical neoplasia. Moreover, a close association was observed between ANXA1 expression and tumour cell differentiation in ISCC. These preliminary results indicate that ANXA1 may be an effective candidate for detecting CIN lesions and for evaluating tumour cell differentiation in squamous cell carcinoma of the cervix.

Proteomic analysis of human articular cartilage: identification of differentially expressed proteins in knee osteoarthritis

OBJECTIVES

The mechanisms underlying the development of age related osteoarthritis (OA) remain unclear. To better understand the pathogenesis of OA and the molecular basis of progressive destruction of articular cartilage in OA, we compared the proteome of OA cartilage with that of normal cartilage.

METHODS

After removal of proteoglycans and collagens, proteins extracted from either normal or OA knee joint cartilage were separated by two-dimensional gel electrophoresis (2-DE). The differentially expressed proteins in OA cartilage were chosen to be further identified by linear ion trap-Fourier transform ion cyclotron resonance mass spectrometry (LTQ-FT/MS).

RESULTS

A total of 1436+/-49 or 1472+/-7 protein spots were resolved by 2-DE of normal or OA cartilage extractions, respectively. Sixteen spots from OA cartilage samples were found to have statistically significant changes in the amount of protein compared with normal samples. Of 16 spots, the identities of 14 proteins were unambiguously determined by LTQ-FT/MS. These OA associated proteins fell into five groups, including glycolysis and energy production (ADH, ADK, ENOA, KPYM and FR), signaling (ANNX-I, PEBP and TUB), Redox (PRDX3 and SODM), and cartilage matrix (COLL-I and COLL-VI). Interestingly, two novel RING (Really Interesting New Gene) domain-containing proteins, RF, Zn-RF, were identified, suggesting novel pathways of cartilage protein regulation.

CONCLUSIONS

This study shows that 2-DE followed by LTQ-FT/MS can be successfully used to characterize the proteome of cartilage without in vitro culturing which could obfuscate physiological differences. The definition of unique OA-associated proteins described here provides significant mechanistic insights into OA by corroborating previously suggested mechanisms and by defining unique players with roles yet to be defined in disease pathogenesis.

Overexpression of annexin a1 induced by terephthalic acid calculi in rat bladder cancer

Prolonged cell proliferation in response to irritation by bladder calculi can evoke malignant transformation of the urothelium. However, the molecular mechanisms responsible for calculi-associated bladder carcinogenesis are unknown. We compared the protein expression pattern of rat bladder transitional cell carcinomas (TCCs) induced by terephthalic acid with that of normal bladder tissues using 2-DE. Comparative analysis of the respective spot patterns on 2-DE showed 146 spots that were markedly changed in TCC samples. Subsequently, 56 of the variant protein spots were identified by MALDI-TOF MS. Among them, overexpression of annexin a1 (ANNA1) in rat TCCs was confirmed by Western blotting and real-time RT-PCR analysis. Immunohistochemical staining revealed that ANNA1, usually a cytoplasmic protein in normal urothelium, was translocated to the nucleus in rat bladder cancer cells. In contrast to the animal studies, examination of human clinical specimens showed that ANNA1 expression was reduced in TCC compared to normal urothelium. The expression of ANNA1 was inversely related to the level of differentiation of TCC. Our data suggest that overexpression of ANNA1 is involved in bladder carcinogenesis induced by bladder calculi and that translocation of the protein may be partly responsible for the effect. ANNA1 may serve as a new marker of differentiation for the histopathological grading of human TCC.

Role of annexin 1 gene expression in mouse craniofacial bone development

BACKGROUND

Annexin 1 is a 37-kDa protein that has complex intra- and extracellular effects. To discover whether the absence of this protein alters bone development, we monitored this event in the annexin-A1 null mice in comparison with littermate wild-type controls.

METHODS

Radiographic and densitometry methods were used for the assessment of bone in annexin-A1 null mice at a gross level. We used whole-skeleton staining, histological analysis, and Western blotting techniques to monitor changes at the tissue and cellular levels.

RESULTS

There were no gross differences in the appendicular skeleton between the genotypes, but an anomalous development of the skull was observed in the annexin-A1 null mice. This was characterized in the newborn annexin-A1 null animals by a delayed intramembranous ossification of the skull, incomplete fusion of the interfrontal suture and palatine bone, and the presence of an abnormal suture structure. The annexin-A1 gene was shown to be active in osteocytes during this phase and COX-2 was abundantly expressed in cartilage and bone taken from annexin-A1 null mice.

CONCLUSIONS

Expression of the annexin-A1 gene is important for the normal development of the skull in mice, possibly through the regulation of osteoblast differentiation and a secondary effect on the expression of components of the cPLA2-COX-2 system.

Annexin 1: Differential expression in tumor and mast cells in human larynx cancer

Annexin 1 protein (ANXA1) expression was evaluated in tumor and mast cells in human larynx cancer and control epithelium. The effect of the exogenous ANXA1 (peptide Ac 2-26) was also examined during the cellular growth of the Hep-2 human larynx epidermoid carcinoma cell line. This peptide inhibited the proliferation of the Hep-2 cells within 144 hr. In surgical tissue specimens from 20 patients with larynx cancer, ultrastructural immunocytochemistry analysis showed in vivo down-regulation of ANXA1 expression in the tumor and increased in mast cells and Hep-2 cells treated with peptide Ac2-26. Combined in vivo and in vitro analysis demonstrated that ANXA1 plays a regulatory role in laryngeal cancer cell growth. We believe that a better understanding of the regulatory mechanisms of ANXA1 in tumor and mast cells may lead to future biological targets for the therapeutic intervention of human larynx cancer.

Annexin 1 Negatively Regulates IL-6 Expression via Effects on p38 MAPK and MAPK Phosphatase-1

Annexin 1 (Anx-1) is a mediator of the anti-inflammatory actions of glucocorticoids, but the mechanism of its anti-inflammatory effects is not known. We investigated the role of Anx-1 in the regulation of the proinflammatory cytokine, IL-6. Lung fibroblast cell lines derived from Anx-1(-/-) and wild-type (WT) mice were treated with dexamethasone and/or IL-1. IL-6 mRNA and protein were measured using real-time PCR and ELISA, and MAPK pathway activation was studied. Compared with WT cells, unstimulated Anx-1(-/-) cells exhibited dramatically increased basal IL-6 mRNA and protein expression. In concert with this result, Anx-1 deficiency was associated with increased basal phosphorylated p38, JNK, and ERK1/2 MAPKs. IL-1-inducible phosphorylated p38 was also increased in Anx-1(-/-) cells. The increase in IL-6 release in Anx-1(-/-) cells was inhibited by inhibition of p38 MAPK. Anx-1(-/-) cells were less sensitive to dexamethasone inhibition of IL-6 mRNA expression than WT cells, although inhibition by dexamethasone of IL-6 protein was similar. MAPK phosphatase-1 (MKP-1), a glucocorticoid-induced negative regulator of MAPK activation, was up-regulated by dexamethasone in WT cells, but this effect of dexamethasone was significantly impaired in Anx-1(-/-) cells. Treatment of Anx-1(-/-) cells with Anx-1 N-terminal peptide restored MKP-1 expression and inhibited p38 MAPK activity. These data demonstrate that Anx-1 is an endogenous inhibitory regulator of MAPK activation and IL-6 expression, and that Anx-1 is required for glucocorticoid up-regulation of MKP-1. Therapeutic manipulation of Anx-1 could provide glucocorticoid-mimicking effects in inflammatory disease.

Proteomic analysis of differential protein expression in early process of pancreatic regeneration in pancreatectomized rats

AIM

A broad-range proteomic approach was applied to investigate the complexity of the mechanisms involved in pancreatic regeneration for identification of new targets of diabetes treatment and potential markers of pancreatic stem cells.

METHODS

A regeneration pancreatic model was induced by 90% partial pancreatectomy (Px) in rats. Changes in the protein expression in regenerating rat pancreas on the third day after Px, as compared with rats that received sham surgery, were analyzed by using 2-D gel electrophoresis (2-DE), mass spectrometry (MS), and mass fingerprinting.

RESULTS

2-DE revealed 91 spots with at least 1.5-fold increases in expression at 3 d after pancreatectomy and 53 differentially expressed proteins that were identified by peptide mass fingerprinting (PMF). These included cell growth-related, lipid and energy metabolism-related, protein and amino acid metabolism-related proteins, and signal transduction proteins. Vimentin, CK8, L-plastin, hnRNP A2/B1, and AGAT are associated with embryogenesis and cell differentiation, and may be new potential pancreatic stem cells markers.

CONCLUSION

The proteome profiling technique provided a broad-based and effective approach for the rapid assimilation and identification of adaptive protein changes during pancreas regeneration induced by pancreatectomy. Our data clarify the global proteome during the pancreatic proliferation and differentiation processes, which is important for better understanding of pancreatic regeneration and for discovering of protein biomarkers for pancreatic stem cells.

Macrophage biology in the Anx-A1-/- mouse

Historical data suggested that a soluble protein, since identified as annexin-A1 (Anx-A1) was released from macrophages following glucocorticoid stimulation and could modulate eicosanoid production and other functions of these cells. Here, we review some recent findings using a line of Anx-A1(-/-) mice to explore the impact of Anx-A1 gene deletion on macrophage biology. The absence of Anx-A1 selectively alters phagocytic capacity of rodent resident peritoneal macrophages apparently through changes in surface adhesion molecule expression. Anx-A1 is also apparently important in the tonic down-regulation of other macrophage functions such as COX-2 induction, PGE(2) release and the production of reactive oxygen species.

Identification of Porcine Oocyte Proteins That Are Associated with Somatic Cell Nuclei after Co-Incubation1

Relatively little is known with respect to the oocyte proteins that are involved in nuclear reprogramming of somatic cells in mammals. The aim of the present study was to use a cell-free incubation system between porcine oocyte proteins and somatic cell nuclei and to identify oocyte proteins that remain associated with these somatic cell nuclei. In two separate experiments, porcine oocytes were either labeled with biotin to label total proteins at the germinal vesicle stage or metaphase II stage or they were labeled with 0.1 mM (35)S-methionine either during the first 6 h or 22-28 h of in vitro maturation to characterize protein synthesis during two distinct phases. To determine which oocyte proteins associate with somatic nuclei, labeled proteins were incubated in a collecting buffer and energy-regenerating system with isolated ovarian epithelial-like cell nuclei. After incubation, the nuclei were subjected to a novel affinity-binding system to recover biotin-labeled oocyte proteins or two-dimensional SDS-PAGE for separation and visualization of radiolabeled proteins. Proteins of interest were sent for identification using either matrix-assisted laser desorption/ionization time of flight or liquid chromatography-tandem mass spectrometry. Of the proteins that remain associated with isolated nuclei after incubation, 4 were identified using the affinity-binding system and 24 were identified using mass spectrometry and the two-dimensional gel interface. This study has identified porcine oocyte proteins that associate with somatic cell nuclei in a cell-free system using proteomics techniques, providing a novel way to identify oocyte proteins potentially functionally involved in nuclear reprogramming.

Modulation of inflammation and response to dexamethasone by Annexin 1 in antigen-induced arthritis

OBJECTIVE

Annexin 1 (Anx-1) is a putative mediator of the antiinflammatory actions of glucocorticoids (GCs). This study investigated the role of Anx-1 in experimental arthritis and in GC-mediated inhibition of inflammation, using antigen-induced arthritis (AIA) in Anx-1 knockout (Anx-1(-/-)) mice.

METHODS

Arthritis was induced by intraarticular injection of methylated BSA (mBSA) in mice preimmunized with mBSA. Disease was assessed after 7 days by histologic examination of the knee joints. Serum levels of anti-mBSA IgG were determined by enzyme-linked immunosorbent assay. Cytokine messenger RNA (mRNA) expression was detected by real-time polymerase chain reaction.

RESULTS

A significant exacerbation of arthritis was observed in the Anx-1(-/-) mice compared with wild-type (WT) mice. This was associated with increased mRNA expression of synovial interleukin-1 beta, tumor necrosis factor alpha, interleukin-6, and macrophage migration inhibitory factor. Dexamethasone significantly reduced the histologic severity of synovitis and bone damage in the WT mice, but exerted no inhibitory effects in the Anx-1(-/-) mice, and also significantly reduced the serum levels of anti-mBSA IgG and the numbers of peripheral blood neutrophils and lymphocytes in WT mice, but had no such effect in Anx-1(-/-) mice.

CONCLUSION

Anx-1 exerts endogenous antiinflammatory effects on AIA via the regulation of cytokine gene expression, and also mediates the antiinflammatory actions of dexamethasone in AIA.

Annexin A1 down-regulation in head and neck cancer is associated with epithelial differentiation status

Annexin A1 (ANXA1) protein expression was evaluated by Western blot in a series of 32 head and neck squamous cell carcinomas (HNSCCs) in a search for molecular alterations that could serve as useful diagnostic/prognostic markers. ANXA1 down-regulation was observed in 24 cases (75%) compared with patient-matched normal epithelium. In relation to clinicopathological variables, ANXA1 down-regulation was significantly associated with advanced T stages (P = 0.029), locoregional lymph node metastases (P = 0.038), advanced disease stage (P = 0.006), hypopharyngeal localization (P = 0.038), and poor histological differentiation (P = 0.005). ANXA1 expression was also analyzed by immunohistochemistry in paraffin-embedded sections from 22 of 32 HNSCCs and 8 premalignant lesions. All dysplastic tissues showed significantly reduced ANXA1 expression compared to a strong positive signal observed in adjacent normal epithelia (except basal and suprabasal cells). A close association was observed between ANXA1 expression and the histological grade in HNSCC. Well-differentiated tumors presented a positive ANXA1 signal in highly keratinized areas whereas moderately and poorly differentiated tumors exhibited very weak or negative staining. Our findings clearly identify ANXA1 as an effective differentiation marker for the histopathological grading of HNSCCs and for the detection of epithelial dysplasia.

Expression, subcellular localization and phosphorylation status of annexins 1 and 5 in human pituitary adenomas and a growth hormone-secreting carcinoma

OBJECTIVE

Annexin 1 (ANXA1), a 37-kDa protein, plays an important role as a mediator of glucocorticoid action in the anterior pituitary gland and has been implicated in the processes of tumorigenesis in a number of other tissues. As a prelude to examining the potential role of ANXA1 in the pathophysiology of pituitary tumours, this study examined the expression, phosphorylation status and distribution of ANXA1 and the closely related protein, annexin 5 (ANXA5), in a series of pituitary adenomas and in two carcinomas.

PATIENTS AND DESIGN

Forty-two human pituitary adenomas were examined. Parallel studies were performed on normal pituitary tissue, obtained postmortem, a GH-secreting carcinoma and a grade 4 astrocytoma.

MEASUREMENTS

The tissue was processed for analysis of ANXA1 mRNA and protein expression by reverse transcriptase polymerase chain reaction (RT-PCR), Western blot analysis and immunogold electron-microscopic histochemistry. Parallel measures of ANXA5 mRNA and protein were also made.

RESULTS

ANXA1 mRNA and protein were detected in all but three adenomas studied; the protein was localized mainly, but not exclusively, to nonendocrine cells. ANXA5 expression was more variable and was contained within both endocrine and nonendocrine cells of these tumours. In comparison with the adenomas, the GH-secreting carcinoma showed abundant expression of both ANXA1 and ANXA5, with intense ANXA1 staining in some but not all tumour/endocrine cells. A serine-phosphorylated species of ANXA1 was detected in all pituitary tumours studied; by contrast, tyrosine-phosphorylated ANXA1 was detected in only four adenomas and in the GH carcinoma. ANXA1 and ANXA5 were also expressed in abundance in the astrocytoma.

CONCLUSIONS

The results demonstrate expression of both ANXA1 and ANXA5 in human pituitary tumours and thus raise the possibility that these proteins influence the growth and/or functional activity of the tumours.

Expresión de las anexinas a1 y a2 en la mucosa del tracto aerodigestivo superior

INTRODUCTION

Annexins A1 and A2 have been related with the maintenance of tissue integrity. They have been identified in a wide variety of tissues, but little is known regarding their expression in upper the aerodigestive tract. The aim of this work is to describe the expression of these proteins in the mucosa of the upper aerodigestive tract.

MATERIAL AND METHODS

Tissue samples from respiratory (nasal and laryngeal) and digestive (oral and pharyngeal) mucosa from non-oncological patients were studied. Annexin A1 and A2 expression was determined by immunohistochemistry.

RESULTS

Both annexins were expressed in the ciliated and in the stratified non-keratinized epithelia, but with a different pattern; ANXA1 was expressed in the more differentiated cells whereas ANXA2 was expressed in the less differentiated ones (with the exception of the cilia of ciliated cells).

CONCLUSION

Although annexins A1 and A2 are structurally and philogenetically related its expression pattern in the upper aerodigestive tract suggests that they have different functions.

Attenuation of glucocorticoid functions in an Anx-A1-/- cell line

The Ca(2+)- and phospholipid-binding protein Anx-A1 (annexin 1; lipocortin 1) has been described both as an inhibitor of phospholipase A(2) (PLA(2)) activity and as a mediator of glucocorticoid-regulated cell growth and eicosanoid generation. Here we show that, when compared with Anx-A1(+/+) cells, lung fibroblast cell lines derived from the Anx-A1(-/-) mouse exhibit an altered morphology characterized by a spindle-shaped appearance and an accumulation of intracellular organelles. Unlike their wild-type counterparts, Anx-A1(-/-) cells also overexpress cyclo-oxygenase 2 (COX 2), cytosolic PLA(2) and secretory PLA(2) and in response to fetal calf serum, exhibit an exaggerated release of eicosanoids, which is insensitive to dexamethasone (10(-8)- 10(-6) M) inhibition. Proliferation and serum-induced progression of Anx-A1(+/+) cells from G(0)/G(1) into S phase, and the associated expression of extracellular signal-regulated kinase 2 (ERK2), cyclin-dependent kinase 4 (cdk4) and COX 2, is strongly inhibited by dexamethasone, whereas Anx-A1(-/-) cells are refractory to the drug. Loss of the response to dexamethasone in Anx-A1(-/-) cells occurs against a background of no apparent change in glucocorticoid receptor expression or sensitivity to non-steroidal anti-inflammatory drugs. Taken together, these observations suggest strongly that Anx-A1 functions as an inhibitor of signal-transduction pathways that lead to cell proliferation and may help to explain how glucocorticoids regulate these processes.

Dexamethasone induces rapid serine-phosphorylation and membrane translocation of annexin 1 in a human folliculostellate cell line via a novel nongenomic mechanism involving the glucocorticoid receptor, protein kinase C, phosphatidylinositol 3-kinase, and mitogen-activated protein kinase

Our recent studies on rat pituitary tissue suggest that the annexin 1 (ANXA1)-dependent inhibitory actions of glucocorticoids on ACTH secretion are effected via a paracrine mechanism that involves protein kinase C (PKC)-dependent translocation of a serine-phosphorylated species of ANXA1 (Ser-P-ANXA1) to the plasma membrane of the nonsecretory folliculostellate cells. In the present study, we have used a human folliculostellate cell line (PDFS) to explore the signaling mechanisms that cause the translocation of Ser-P-ANXA1 to the membrane together with Western blot analysis and flow cytometry to detect the phosphorylated protein. Exposure of PDFS cells to dexamethasone caused time-dependent increases in the expression of ANXA1 mRNA and protein, which were first detected within 2 h of steroid contact. This genomic response was preceded by the appearance within 30 min of substantially increased amounts of Ser-P-ANXA1 and by translocation of the phosphorylated protein to the cell surface. The prompt membrane translocation of Ser-P-ANXA1 provoked by dexamethasone was inhibited by the glucocorticoid receptor, antagonist, mifepristone, but not by actinomycin D or cycloheximide, which effectively inhibit mRNA and protein synthesis respectively in our preparation. It was also inhibited by a nonselective PKC inhibitor (PKC(9-31)), by a selective inhibitor of Ca(2+)-dependent PKCs (Go 6976) and by annexin 5 (which sequesters PKC in other systems). In addition, blockade of phosphatidylinositiol 3-kinase (wortmannin) or MAPK pathways with PD 98059 or UO 126 (selective for MAPK kinse 1 and 2) prevented the steroid-induced translocation of Ser-P-ANXA1 to the cell surface. These results suggest that glucocorticoids induce rapid serine phosphorylation and membrane translocation of ANXA1 via a novel nongenomic, glucocorticoid receptor-dependent mechanism that requires MAPK, phosphatidylinositiol 3-kinase, and Ca(2+)-dependent PKC pathways.

Aberrant inflammation and resistance to glucocorticoids in annexin 1-/- mouse

The 37-kDa protein annexin 1 (Anx-1; lipocortin 1) has been implicated in the regulation of phagocytosis, cell signaling, and proliferation and is postulated to be a mediator of glucocorticoid action in inflammation and in the control of anterior pituitary hormone release. Here, we report that mice lacking the Anx-1 gene exhibit a complex phenotype that includes an altered expression of other annexins as well as of COX-2 and cPLA2. In carrageenin- or zymosan-induced inflammation, Anx-1-/- mice exhibit an exaggerated response to the stimuli characterized by an increase in leukocyte emigration and IL-1beta generation and a partial or complete resistance to the antiinflammatory effects of glucocorticoids. Anx-1-/- polymorphonuclear leucocytes exhibited increased spontaneous migratory behavior in vivo whereas in vitro, leukocytes from Anx-1-/- mice had reduced cell surface CD 11b (MAC-1) but enhanced CD62L (L-selectin) expression and Anx-1-/- macrophages exhibited anomalies in phagocytosis. There are also gender differences in activated leukocyte behavior in the Anx-1-/- mice that are not seen in the wild-type animals, suggesting an interaction between sex hormones and inflammation in Anx-1-/- animals.

Three isoforms of annexin I are preferentially expressed in normal esophageal epithelia but down-regulated in esophageal squamous cell carcinomas

The development and progression of human cancer are believed to be due to the alterations of multiple genes or/and their protein products. For identifying the proteins associated with esophageal cancer, we analysed the protein profiles of 24 pairs of esophageal squamous cell carcinomas/matched adjacent normal epithelia. Microdissection of routinely unstained frozen sections was performed to purify cancerous and epithelial cells. The protein expression profiles were obtained by two-dimensional electrophoresis. Selected proteins dysregulated in tumors were identified by MALDI-TOF-MS. Three isoforms of annexin I were detected in normal esophageal mucosa and down-regulated in esophageal squamous cell carcinomas. RT-PCR analysis showed annexin I mRNA levels were significantly reduced in 17 out of 24 carcinomas. Immunohistochemistry demonstrated that annexin I appeared strong positive in all normal epithelia layers except basal cells. In cancer tissues, decreased expression of annexin I was observed in 12 out of 16 well differentiated tumors, 16 out of 17 moderately differentiated tumors, and 3 out of 3 poorly differentiated tumors as compared with the corresponding normal esophageal epithelia. There was a significant correlation between annexin I expression and the status of tumor differentiation. Well differentiated tumors presented stronger immunohistochemical reaction than moderately and poorly differentiated tumors. These data suggested that there existed three different isoforms of annexin I in normal esophageal epithelia, which may be the results of post-translational modification. Down-expression of three annexin I isoforms was a frequent event in esophageal carcinogenesis.

Annexin 1 (lipocortin 1) mimics inhibitory effects of glucocorticoids on testosterone secretion and enhances effects of interleukin-1beta

Annexin 1 is an important mediator of glucocorticoid action in the hypothalamo-pituitary axis; however, little is known of its role in mediating glucocorticoid actions in the peripheral endocrine organs. Accordingly, we have carried out a preliminary study to investigate the effects of annexin 1 in vitro on the testicular secretion of testosterone, a process inhibited by both glucocorticoids and interleukin-1beta (IL-1beta). Luteinizing hormone (LH) and forskolin stimulated the release of testosterone from dispersed murine testicular cells in vitro. Their effects were reduced in cells from mice pretreated with dexamethasone (DEX). Similarly, preincubation of testicular cells from untreated mice with DEX, corticosterone, or 11-dehydrocorticosterone reduced LH-stimulated testosterone release, as did the 11beta-hydroxysteroid dehydrogenase inhibitors, glycyrrhetinic acid and carbenoxolone. The inhibitory actions of the steroids were mimicked by annexin 1(1-188) (ANXA1(1-188)) (a stable annexin 1 analog). IL-1beta produced a marked decrease in the response to LH, which was blocked by indomethacin, a nonselective cyclooxygenase inhibitor and an additive effect with DEX and ANXA1(1-188). These results confirm reports that glucocorticoids and IL-1beta inhibit LH-stimulated testosterone release from mouse testicular cells. They also show, for the first time, that the effects of the steroids are mimicked by annexin 1 and that, in contrast to their mutually antagonistic effects in the neuroendocrine system, IL-1beta and annexin 1 exert additive actions in the testis.

Down-regulation of annexin A10 in hepatocellular carcinoma is associated with vascular invasion, early recurrence, and poor prognosis in synergy with p53 mutation

Annexins (ANXs) are a large group of calcium-binding proteins participating in diverse important biological processes. ANXA10 is the least expressed new member of unknown function. We showed that ANXA10 mRNA was expressed in adult liver and hepatocellular carcinoma (HCC), but not in multiple adult and fetal tissues, cholangiocarcinoma, and several other common carcinomas. Of 182 unifocal primary HCCs, ANXA10 mRNA was dramatically reduced in 121 (66%), and the down-regulation correlated with p53 mutation (P = 0.024), early intrahepatic tumor recurrence (P = 0.0007), and lower 4-year survival (P = 0.0014). Down-regulation of ANXA10 was twofold more frequent in large than small HCCs (P = 0.0012), in grade II to III than grade I HCC (P < 0.00001), and in stage IIIA to IV than stage I to II HCC (P < 0.00001). Moreover, ANXA10 down-regulation and p53 mutation acted synergistically toward high-grade (P < 0.00001), high-stage HCC (P < 0.00001), and poorer prognosis (P = 0.0025). Our results indicate that the expression of the tissue- and tumor-restricted ANXA10 is a marker of liver cell differentiation and growth arrest, and its down-regulation associated with malignant phenotype of hepatocytes, vascular invasion, and progression of HCC, leading to poor prognosis. Thus, ANXA10 might serve as a new potential target of gene therapy for HCC.

Annexin I modulates cell functions by controlling intracellular calcium release

Annexin I is an intracellular protein in search of a function. Ex vivo it has calcium- and phospholipid-binding properties. To evaluate its role in vivo, MCF-7 cells were stably transfected with annexin I in sense or antisense orientations. In cells overexpressing annexin I, calcium release was abrogated on stimulation of purinergic or bradykinin receptors, whereas non-transfected cells or cells with down-regulated annexin I released calcium within seconds. Basal calcium and calcium stores were not affected. The impaired calcium release was paralleled by a down-regulation of the activities of phospholipase C, group II phospholipase A2, and E-cadherin with altered adhesion and enhanced tumor growth on soft agar. Significantly smaller tumors, with the histologically most differentiated cells, were observed in nude mice inoculated with cells transfected with the antisense rather than with the sense plasmid. These observations indicate that annexin I modulates cell functions by controlling intracellular calcium release. Frey, B. M., Reber, B. F. X., Vishwanath, B. S., Escher, G., Frey, F. J. Annexin I modulates cell functions by controlling intracellular calcium release.

Psoriasis and the arachidonic acid cascade

Arachidonic acid (5.8,11,14-eicosatetraenoic acid C20:4, n-6) is released from the cell membrane by the action of phospholipases on membrane phospholipids. Metabolites of arachidonic acid, which are generically termed eicosanoids, including prostaglandins, thromboxane, leukotrienes and hydroxyeicosatetraenoic acids, have been implicated as mediators or modulators of a number of physiological functions and pathological conditions in both normal and diseased human skin. Particularly, eicosanoids have been suspected to play an important role in the pathogenesis of psoriasis, because a number of phenomena observed in psoriasis can be explained, at least in part, by the action of eicosanoids. This review will focus on recent progress regarding the significance of eicosanoids in the pathogenesis of psoriasis. Recent developments in the molecular biology in the eicosanoids have renewed interest in the role of eicosanoids in psoriasis. New understanding of the etiology of psoriasis and advances in its treatment due to recent progress in eicosanoid biology will also be presented.

Inhibitory effect of annexin I on synovial inflammation in rat adjuvant arthritis

OBJECTIVE

Annexin I is an endogenous antiinflammatory mediator, expressed in rheumatoid arthritis (RA) synovium, the contribution of which to autoregulation of the synovial inflammatory response has not been examined in models of RA. We investigated the antiinflammatory role of annexin I in rat adjuvant arthritis.

METHODS

Rats with adjuvant-induced arthritis (AIA) were treated with a specific anti-annexin I monoclonal antibody (mAb), isotype control IgG, and/or dexamethasone. Clinical outcomes and synovial synthesis of tumor necrosis factor alpha (TNFalpha), prostaglandin E2 (PGE2), and nitric oxide were examined, and annexin I expression was assessed by flow cytometry and reverse transcription-polymerase chain reaction.

RESULTS

Anti-annexin I mAb reversed the effects of dexamethasone on the clinical features of AIA and exacerbated AIA in the absence of exogenous glucocorticoid. Clinical exacerbation of AIA by anti-annexin I mAb was accompanied by significantly increased synovial TNFalpha and PGE2, suggesting that annexin I tonically inhibits the production of these mediators. Anti-annexin I mAb treatment was associated with significantly reduced leukocyte intracellular annexin I, despite increased annexin I messenger RNA expression, consistent with a depletion effect of extracellular mAb via the cell surface.

CONCLUSION

Annexin I is a key endogenous inhibitory mediator of arthritis via mechanisms that include inhibition of cytokine and effector molecule production. Moreover, a synthesis-independent depletion of intracellular annexin I by extracellular antibody supports the hypothesis that externalization of annexin I is involved in its mode of action.

De novo expression of lipocortin-1 in reactive microglia and astrocytes in kainic acid lesioned rat cerebellum

An understanding of the role of reactive glia in the neurodegenerative/regenerative process requires a knowledge of the molecules synthesised by these cells following trauma. We investigated the cellular localisation of lipocortin-1 (LC-1), a putative neuroprotective agent, in cryostat sections of normal and kainic acid lesioned rat cerebellum. In the normal cerebellum lipocortin-1 immunoreactivity was detected in Purkinje cell bodies and molecular layer interneurons. Following kainic acid (1 microg) induced lesions, it was rapidly upregulated in activated microglia, from which it appeared to be secreted. At later time points it was detected in activated astrocytes. LC-1 protein levels were quantified by a sensitive and specific ELISA. Compared to control cerebellum, LC-1 levels were dramatically elevated following lesion, peaking at 3 days: 760% of basal (unlesioned) levels. In situ hybridisation studies revealed a marked upregulation of LC-1 mRNA at 1 and 3 days following the lesion, indicating the transient de novo synthesis of this protein, consistent with a localisation to microglia. In vitro studies, on cultured astrocytes and microglia, demonstrated high levels of intracellular LC-1 in both cell types. LC-1 was detected in microglial but not astrocytic, conditioned media, confirming the in vivo observations that activated microglia may secrete LC-1. Our data show that at early time points following excitotoxic lesion to the cerebellum, it is activated microglia that synthesise and possibly secrete this protein, suggesting an important role of this cell type in immunosuppression and neuroprotection following damage to the central nervous system.

Functional implications of nitric oxide produced by mitochondria in mitochondrial metabolism

The effects of endogenous production of NO., catalysed by the mitochondrial nitric oxide synthase (NOS), on mitochondrial metabolism were studied. The respiratory rates of intact mitochondria in State 4 were decreased by 40% and 28% with succinate and malate-glutamate, respectively, in the presence of L-arginine (L-Arg); conversely, the O2 uptake with NG-methyl-L-arginine (NMMA), a competitive inhibitor of NOS, was increased. The production of NO. and the inhibition of the respiratory rates were dependent on the metabolic state in which mitochondria were maintained: NO. production was probably supported by mitochondrial NADPH, the latter maintained by the energy-dependent transhydrogenase. In addition to the decline in the respiratory rate, an inhibition of ATP synthesis was also observed (40-50%) following supplementation with L-Arg. The dependence of the respiratory rates of mitochondria in State 3 and cytochrome oxidase activities on O2 concentrations with either L-Arg or NMMA indicated that both processes were competitively inhibited by NO. at the cytochrome oxidase level. This inhibition can be explained by the interaction of NO. with cytochrome oxidase at the binuclear centre. The role of NO. as a physiological modulator of cytochrome oxidase is discussed in terms of cellular metabolism.

Functional analysis of the human annexin I and VI gene promoters

To gain insight into the molecular basis of annexin gene expression we have analysed the annexin I and VI gene promoters. A previously described 881 bp sequence immediately upstream of the annexin I transcription start site and a similar size fragment proximal to the annexin VI transcription start site both drove expression of the luciferase reporter gene in fibroblasts and epithelial cells. Neither promoter displayed any sensitivity to dexamethasone, suggesting that the putative glucocorticoid response element in the annexin I promoter is non-functional. Consistent with this, endogenous annexin I gene expression was unaffected by dexamethasone at the mRNA and protein levels in A431 cells. A series of 5' deletions of the two promoters were examined to define the minimal active sequences. For annexin I this corresponded to a sequence approx. 150 bp upstream of the transcription start site that included CAAT and TATA boxes. Unexpectedly, the annexin VI promoter, which also contains CAAT and TATA boxes, was fully active in the absence of these elements, a 53 bp sequence between these boxes and the transcription start site having maximal activity. Electrophoretic mobility-shift assays with nuclear extracts from A431 and HeLa cells with probes corresponding to this region revealed an SP1-binding site. These results show that the annexin I and VI genes have individual modes of transcriptional regulation and that if either annexin I or annexin VI has an anti-inflammatory role, then this is in the absence of steroid-induced gene expression.

A novel Arabidopsis thaliana protein protects tumor cells from tumor necrosis factor-induced apoptosis

Recently we have cloned and characterized a novel, oxidative stress-induced Arabidopsis thaliana gene (oxy5), and showed that expression of oxy5 protects bacterial cells from death caused by oxidative stress. As oxidative stress is one pathway of TNF cytotoxicity, we investigated whether the encoded protein could also protect human tumor cells from TNF killing. We stably transfected the oxy5 gene into TNF-sensitive HeLa D98 cells (D98/O.5), and found that all examined transfectants were highly TNF-resistant in the absence of the protein synthesis inhibitor cycloheximide. The acquired TNF resistance of these clones was accompanied by a sharp decrease in the intracellular formation of reactive oxygen species, suggesting the activation of antioxidant enzymes like superoxide dismutases (SODs). Indeed, D98/O.5 clones showed an increased manganous superoxide dismutase (MnSOD) mRNA and protein expression in the absence or presence of TNF stimulation, whereas the expression of the Cu/ZnSOD was not affected. Furthermore, the elevated MnSOD expression in the D98/O.5 clones correlated well with an increased antioxidative activity, which was specifically due to MnSOD as measured by the suppression of xanthine oxidase. Our results demonstrate a novel role for a plant-derived protein in resistance to TNF cytotoxicity, and that the Arabidopsis thaliana protein Oxy5 can exert its protective function across evolutionary boundaries through activation of antioxidant enzymes like MnSOD.

Suppression by dexamethasone of inducible nitric oxide synthase protein expression in vivo: a possible role for lipocortin 1

Western blot and densitometric analysis of organ homogenates from lipopolysaccharide (LPS)-treated rats (1-10 mg kg(-1), i.p.) exhibited a strong induction of inducible nitric oxide synthase (iNOS) expression seen at all the doses tested (1, 3, and 10 mg kg(-1), n = 3). In particular, 3 hr after challenge of rats with LPS, iNOS was detectable in the liver, kidney, aorta, spleen and lung. Dexamethasone (DEX) (0.1-1 mg kg(-1); -1 hr) dose-dependently reduced iNOS expression in lung homogenates after exposure to LPS (1 mg kg(-1); P < 0.05). A partial reversal of DEX-induced suppression of iNOS expression in lung homogenates 3 hr after challenge with LPS was observed in rats which received a specific anti-lipocortin 1 sheep serum (LCS3; 1 mL kg(-1) 24 hr prior to the steroid), with an inhibition of 35+/-8%, as compared to animals passively immunised with normal sheep serum where dexamethasone exhibited an inhibition of 60+/-7% (n = 4). Peritoneal macrophages collected from rats treated with LPS (1 mg kg(-1); 3 hr) and cultured for 16 hr, released significant amounts of nitrite (51+/-1 microM) into the cell supernatants; this was reduced (-70+/-6%) after pre-treatment with dexamethasone (0.3 mg kg(-1)) and this effect was neutralised if animals were passively immunised with LCS3 (P < 0.01; n = 4). Thus lipocortin 1 mediates, at least in part, the inhibitory action exerted by dexamethasone on both iNOS protein expression in lung and iNOS activity (as measured by nitrite release) in primary peritoneal cells of rats.

Differential expression of annexin I in human mammary ductal epithelial cells in normal and benign and malignant breast tissues

Annexins are a family of structurally related, water-soluble proteins that have calcium- and phospholipid-binding domains. Annexin I is thought to be involved in cell proliferation and differentiation and has recently been shown to be expressed on the surfaces of lymphoma cells where it acts as an endothelial cell adhesion molecule. To evaluate the expression of annexin I in relation to human breast cancer development and progression we used breast biopsy tissues. Immunohistochemical analysis of annexin I in paraffin-embedded ductal epithelial cells of various human breast tissues indicated that this annexin was not demonstrable in the ductal luminal cells of normal breast tissues (n = 11) and benign tumors (n = 10) (except for one ductal adenoma) but was generally expressed in various types of breast cancers, including noninvasive ductal carcinoma in situ (DCIS), invasive and metastatic breast tumors (n = 33). The results suggest that annexin I expression might correlate with malignant breast cancer progression but it is most likely involved at an early stage of human breast cancer development.

Glucocorticoid induced the expression of mRNA and the secretion of lipocortin 1 in rat astrocytoma cells

The lipocortins are a family of structurally related proteins that have been shown to be implicated in multiple aspects of cell biology. Subsequent research has shown that lipocortin 1 (LC1) participates in the physiological and pathological functioning of the CNS and neuroendocrine system. In the present study, the effects of 12-O-tetradecanoylphorbol 13-acetate (TPA), dibutyryl cyclic AMP (Bt2cAMP) or dexamethasone (DEX) on expression of LC1 were investigated by a sandwich enzyme immunoassay and reverse transcription polymerase chain reaction (RT-PCR) in rat astrocytoma (C6) cells. Time-dependent experiments revealed that the intracellular protein content and the mRNA of rat LC1 increased significantly 4 h after TPA (10 mM) or DEX (1 microM) addition. TPA and DEX elicited a prominent induction of LC1 at 10(-8) M and 10(-6) M, respectively. Bt2cAMP (0.5 mM) also appeared to induce, but the induction was not statistically significant. In addition, DEX increased the extracellular secretion of LC1 without cytotoxicity. These results suggest that LC1 synthesis is chemically induced and selectively released from C6 cells by dexamethasone.

Localization of annexin I (lipocortin I, p35) mRNA in normal and diseased human skin by in situ hybridization

Annexin I is a calcium- and phospholipid-binding protein that is involved in the regulation of cellular differentiation. The aim of the present study was to determine the localization of annexin I mRNA expression in normal and diseased human skin. In situ hybridization with a specific digoxigenin-labelled RNA probe was used throughout. We detected no annexin I mRNA signals in basal and suprabasal cells of normal epidermis, but positive signals were evident in the sudoriferous ducts. Annexin I mRNA expression was detected in the keratinizing squamous cells in keratotic type seborrhoeic keratosis and in keratinocytes at the periphery of the horn pearl in well-differentiated squamous cell carcinoma. Positive signals were also seen at the border between involved and noninvolved skin in psoriasis vulgaris and in dyskeratotic epidermal keratinocytes in keratosis follicularis Darier. By contrast, no annexin I mRNA signals were detected in tumour cells in basal cell carcinoma. The present results suggest that annexin I expression is related to, and may play a role in, keratinization disorders.