Annexin A3 as a Marker Protein for Microglia in the Central Nervous System of Rats.

The parenchymal microglia possess different morphological characteristics in cerebral physiological and pathological conditions; thus, visualizing these cells is useful as a means of further investigating parenchymal microglial function. Annexin A3 (ANXA3) is expressed in microglia, but it is unknown whether it can be used as a marker protein for microglia and its physiological function. Here, we compared the distribution and morphology of parenchymal microglia labeled by ANXA3, cluster of differentiation 11b (CD11b), and ionized calcium-binding adaptor molecule 1 (Iba1) and measured the expression of ANXA3 in nonparenchymal macrophages (meningeal and perivascular macrophages). We also investigated the spatiotemporal expression of ANXA3, CD11b, and Iba1 in vivo and in vitro and the cellular function of ANXA3 in microglia. We demonstrated that ANXA3-positive cells were abundant and evenly distributed throughout the whole brain tissue and spinal cord of adult rats. The morphology and distribution of ANXA3-labeled microglia were quite similar to those labeled by the microglial-specific markers CD11b and Iba1 in the central nervous system (CNS). ANXA3 was expressed in the cytoplasm of microglia, and its expression was significantly increased in activated microglia. ANXA3 was almost undetectable in the nonparenchymal macrophages. Meanwhile, the protein and mRNA expression levels of ANXA3 in different regions of the CNS were different from those of CD11b and Iba1. Moreover, knockdown of ANXA3 inhibited the proliferation and migration of microglia, while overexpression of ANXA3 enhanced these activities. This study confirms that ANXA3 may be a novel marker for parenchymal microglia in the CNS of adult rats and enriches our understanding of ANXA3 from expression patterns to physiological function.

miR-18b attenuates cerebral ischemia/reperfusion injury through regulation of ANXA3 and PI3K/Akt signaling pathway.

Recent, research has displayed that the disorders of miR-18b are related to ischemic stroke. Here, we aimed to investigate the underlying neuroprotective mechanism of miR-18b in cerebral ischemia/reperfusion (I/R) injury. Oxygen-glucose deprivation/reperfusion (OGDR) model in vitro and middle cerebral artery occlusion (MCAO) model in vivo were established to simulate cerebral I/R injury. RT-PCR, western blotting, CCK-8, TUNEL, and TTC staining assays were applied in this study to explore the effect of miR-18b on cerebral I/R injury. Results displayed that miR-18b expression was reduced after cerebral I/R injury. Besides, miR-18b showed neuroprotective effects on cerebral I/R injury both in vitro and in vivo, These neuroprotective effects included promoting cell viability, decreasing cell apoptosis, reducing the production of inflammatory cytokines in SH-SY 5Y cells after OGDR and depressing MCAO-induced infarct size, neurological deficits and apoptotic cells in mice. Moreover, miR-18b negatively regulated ANXA3 expression, and its neuroprotection on cerebral I/R injury was overturned by ANXA3. Additionally, increasing miR-18b or decreasing ANXA3 promoted the activation of the PI3K/Akt signaling pathway in SH-SY 5Y cells after cerebral I/R injury. In conclusion, these data indicate that miR-18b protects against cerebral I/R injury by inhibiting ANXA3 and activating PI3K/Akt pathway, which provides a promising therapeutic target for ischemic stroke therapy.

MiR-340-5p is a potential prognostic indicator of colorectal cancer and modulates ANXA3.

OBJECTIVE: MicroRNAs (miRNAs) are increasingly recognized as oncogenes or tumor suppressors in colorectal cancer (CRC). The aim of this study was to explore the expression and functions of miR-340-5p in CRC. PATIENTS AND METHODS: The expression of miR-340-5p in CRC tissues and cell lines was detected by quantitative RT-PCR. Associations of miR-340-5p expression with clinicopathological factors and overall survival (OS) and progression-free survival (PFS) were statistically evaluated. Luciferase assay, RT-PCR, and Western blot were performed to verify the precise target of miR-340-5p. MTT assay, colony formation and transwell assay were performed to determine the proliferation, migration and invasion, respectively. RESULTS: Our results showed that miR-340-5p was significantly down-regulated in CRC tissues and cell lines, and was associated with histological grade (p=0.020), lymph nodes metastasis (p=0.003) and TNM stage (p=0.007). Furthermore, Kaplan-Meier and log-rank tests revealed that patients with low expression of miR-340-5p had a shorter OS (p=0.0110) and PFS (p=0.0032) than those with high expression of miR-340-5p. We further validated Annexin A3 (ANXA3) was a direct target of miR-340-5p in CRC. The functional assay showed that up-regulation of miR-340-5p or down-regulation of ANXA3 can both inhibit CRC cell proliferation, migration, and invasion. Besides, the re-expression of ANXA3 reversed the miR-340-5p induced suppression of cell proliferation, migration and invasion. CONCLUSIONS: Our data demonstrated that miR-340-5p exerted its tumor-suppressive function by directly targeting ANXA3 in CRC, suggesting that miR-340-5p might represent a novel prognostic biomarker and therapeutic target for CRC.

Annexin A3 as a Prognostic Biomarker for Breast Cancer: A Retrospective Study.

To validate the correlation between ANXA3 expression and prognosis in breast cancer, a retrospective study encompassing 309 breast cancer patients was performed. The expression of ANXA3 was determined by the immunohistochemical examination of tissue sections by the Max Vision™ method. The ANXA3 levels in the patient samples were validated for the prognosis based on age, menopause status, tumor size, tumor node, metastasis stage, the number of lymphatic metastases, oncology grade, and molecular subtyping. An elevated expression of ANXA3 was detected in breast cancer samples, compared to adjacent tissue samples, and significant correlation depending on the number of lymphatic metastases (P = 0.001) and histological grade (P = 0.004) was observed. The number of lymphatic metastases and ANXA3 expression were identified as independent risk factors affecting the disease-free survival and overall survival. Significantly (P < 0.002) higher level of ANXA3 was detected in triple-negative breast cancer compared to other subtypes. There was no significant (P > 0.05) change in the expression of ANXA3 with respect to age, menopausal status, tumor size, and clinical stage. The findings implicate the expression of ANXA3 with the natural progression of breast cancer and associate it with increased lymphatic metastasis. The study validates the use of ANXA3 as a potential prognosis biomarker for breast cancer.

Proteomic analysis of ginsenoside Re attenuates hydrogen peroxide-induced oxidative stress in human umbilical vein endothelial cells.

Ginsenoside Re is an active component in ginseng that has attracted much attention because of its evident therapeutic effects on the cardiovascular system. However, little basic information is available on the mechanisms and pharmacological effects of ginsenoside Re. The potential mechanisms and protective effects of Re on H2O2-induced oxidative injury in human umbilical vein endothelial cells (HUVECs) were investigated in this study. An oxidative injury model was established using H2O2. The anti-oxidative effects of Re were determined using a series of experiments, such as MTT and anti-oxidative indicator assays. The potential protective mechanisms of Re were explored at the proteomic level, and differentially expressed proteins were validated by quantitative real-time polymerase chain reaction and western blotting. Results indicated that Re could be a potential anti-oxidant to protect HUVECs against oxidative stress damage. Proteomic analysis showed that the expression of 23 protein spots was upregulated in Re and H2O2 groups to resist oxidative stress, 15 of which were identified by their mass spectrum. These upregulated proteins were involved in stress response, anti-oxidative systems, protein synthesis, regulation of transcription and post-translational modifications, and repair of mitochondrial functions. This study may provide new insights into the mechanisms of ginsenoside Re in protecting the cardiovascular system.

ANXA3/JNK Signaling Promotes Self-Renewal and Tumor Growth, and Its Blockade Provides a Therapeutic Target for Hepatocellular Carcinoma.

Frequent tumor relapse in hepatocellular carcinoma (HCC) has been commonly attributed to the presence of residual cancer stem cells (CSCs) after conventional treatments. We have previously identified and characterized CD133 to mark a specific CSC subset in HCC. In the present study, we found endogenous and secretory annexin A3 (ANXA3) to play pivotal roles in promoting cancer and stem cell-like features in CD133+ liver CSCs through a dysregulated JNK pathway. Blockade of ANXA3 with an anti-ANXA3 monoclonal antibody in vitro as well as in human HCC xenograft models resulted in a significant reduction in tumor growth and self-renewal. Clinically, ANXA3 expression in HCC patient sera closely associated with aggressive clinical features. Our results suggest that ANXA3 can serve as a novel diagnostic biomarker and that the inhibition of ANXA3 may be a viable therapeutic option for the treatment of CD133+ liver-CSC-driven HCC.

Expression of annexin A3 in gastric cancer and its correlation with proliferation and apoptosis.

Annexin A3 has been identified as a novel biomarker in different types of cancers. However, little is known about its clinical significances and and biological roles in gastric cancer. In this study, we assessed annexin A3 expression in 80 patients with gastric cancer and explore its correlation with prognosis Moreover, correlations with Ki-67, Bcl-2 and Bax were also investigated. Expression of annexin A3 was increased in gastric cancer compared with that in normal gastric tissues. Annexin A3 expression was significantly associated with tumor volume and TNM stage (p<0.05). and inversely correlation with prognosis of patients. More interestingly, expression of annexin A3 was positive correlated with Ki-67 and Bcl-2 expression. Our study showed annexin A3 might be a potential prognostic marker for gastric cancer and involved in tumorigenesis by regulating apoptosis and proliferation.

Regulatory mechanisms of annexin-induced chemotherapy resistance in cisplatin resistant lung adenocarcinoma.

Adenocarcinoma of lung has high incidence and a poor prognosis, woith chemotherapy as the main therapeutic tool, most commonly with cisplatin. However, chemotherapy resistance develops in the majority of patients during clinic treatment. Mechanisms of resistance are complex and still unclear. Although annexin play important roles in various tumor resistance mechanisms, their actions in cisplatin-resistant lung adenocarcinoma remain unclear. Preliminary studies by our group found that in cisplatin-resistant lung cancer A549 cells and lung adenocarcinoma tissues, both mRNA and protein expression of annexins A1, A2 and A3 is increased. Using a library of annexin A1, A2 and A3 targeting combined molecules already established by ourselves we found that specific targeting decreased cisplatin-resistance. Taken together, the underlined effects of annexins A1, A2 and A3 on drug resistance and suggest molecular mechanisms in cisplatin-resistant A549 cells both in vivo and in vitro. Furthermore, the study points to improved research on occurrence and development of lung adenocarcinoma, with provision of effective targets and programmes for lung adenocarcinoma therapy in the clinic.

Decreased annexin A3 expression correlates with tumor progression in papillary thyroid cancer.

PURPOSE: The aim of this study is to identify the potential tumor markers that function in carcinogenesis and tumor progression, thus providing important diagnostic and prognostic information. EXPERIMENTAL DESIGN: We performed 2-D gel electrophoresis and MALDI-TOF MS to investigate the differentially expressed proteins in 25 papillary thyroid carcinoma tissues. For validation of candidate proteins and investigation of clinical significance, we performed Western, Northern blot analysis and immunohistochemical staining. RESULTS: Our proteomic analyses revealed significantly decreased annexin A3 expression in papillary thyroid carcinoma at both the protein and mRNA levels, compared with normal thyroid tissue. ANXA3 immunoreactivity was not significantly correlated with lymph node metastasis, multifocality, capsular invasion or perithyroidal extension in thyroid cancer. However, the tumor subgroup with a lymph node metastasis score of >3 displayed significantly lower ANXA3 expression than did subgroups with negative and ≤3 scores (p=0.001). Moreover, ANXA3 expression was markedly lower in large tumors (>1 cm in diameter) than in microcarcinomas (p=0.001). CONCLUSION AND CLINICAL RELEVANCE: Decreased expression of ANXA3 in papillary thyroid cancer supports the idea that ANXA3 may be an effective marker of microcarcinoma, and a negative predictor of papillary thyroid cancer progression.

Annexin A3 is associated with cell death in lactacystin-mediated neuronal injury.

Massive neuronal apoptosis and accumulation of protein aggregates in the cortex and hippocampus of the brain are hallmarks of several neurodegenerative disorders, indicating ubiquitin proteasome system (UPS) dysfunction. Lactacystin, a classical proteasome inhibitor, is used to simulate ubiquitin proteasome system dysfunction in neurons to mimic pathological features of neurodegenerative disorders. Based on Western blot analyses, we reported for the first time that annexin A3 (AnxA3) is not only endogenously expressed in mouse cortical neurons but also more importantly, by gene expression microarray and real-time RT-PCR that it is greatly transcriptional up-regulated to approximately 11- and 15-fold, respectively in murine primary cortical neurons with 1µM lactacystin for 24h. Up-regulation of AnxA3 expression occurred after 12-15h post-lactacystin treatment, which corresponded with the onset of neuronal injury, with approximately 25% of the neurons being non-viable by that time interval. Western blot analysis with anti-AnxA3 antibodies further validated that up-regulation of AnxA3 only occurs with onset of neuronal death, and not with the onset of proteasome inhibition, which occurs at 4.5h post-lactacystin treatment. Over-expression studies suggested AnxA3 might be involved in death promotion during lactacystin-mediated neuronal death, since caspase-3 activation was significantly stronger upon neuronal AnxA3 over-expression. We propose AnxA3 up-regulation may have significant relevance in the elucidation of neurodegenerative pathophysiology.

Primary cell cultures from human renal cortex and renal-cell carcinoma evidence a differential expression of two spliced isoforms of Annexin A3.

Primary cell cultures from renal cell carcinoma (RCC) and normal renal cortex tissue of 60 patients have been established, with high efficiency (more than 70%) and reproducibility, and extensively characterized. These cultures composed of more than 90% of normal or tumor tubular cells have been instrumental for molecular characterization of Annexin A3 (AnxA3), never extensively studied before in RCC cells although AnxA3 has a prognostic relevance in some cancer and it has been suggested to be involved in the hypoxia-inducible factor-1 pathway. Western blot analysis of 20 matched cortex/RCC culture lysates showed two AnxA3 protein bands of 36 and 33 kDa, and two-dimensional Western blot evidenced several specific protein spots. In RCC cultures the 36-kDa isoform was significantly down-regulated and the 33-kDa isoform up-regulated. Furthermore, the inversion of the quantitative expression pattern of two AnxA3 isoforms in tumor cultures correlate with hypoxia-inducible factor-1alpha expression. The total AnxA3 protein is down-regulated in RCC cultures as confirmed also in tissues by tissue microarray. Two AnxA3 transcripts that differ for alternative splicing of exon III have been also detected. Real-time PCR quantification in 19 matched cortex/RCC cultures confirms the down-regulation of longer isoform in RCC cells. The characteristic expression pattern of AnxA3 in normal and tumor renal cells, documented in our primary cultures, may open new insight in RCC management.

Comparative proteomic analysis of human placenta derived from assisted reproductive technology.

The aim of this study was to use proteomics-based approach to examine differences in protein expression in placenta derived from assisted reproductive technology (ART) and normal pregnancy. Using 2-DE we found that, compared with the control group, 12 spots in standard in vitro fertilization group and 18 spots in intracytoplasmic sperm injection group were identified as significantly differentially expressed proteins. Among them, six spots were differentially expressed in both standard IVF and ICSI groups with the same change tendency. Totally, 20 proteins were successfully identified by MALDI TOF/TOF MS, including proteins involved in the membrane traffic, metabolism, nucleic acid processing, stress response and cytoskeleton. Notably, five proteins detected to be differentially expressed in both ART groups were identified as annexin A3, hnRNP C1/C2, alpha-SNAP, FTL and ATP5A. Some of the proteins were confirmed by Western blot and immunohistochemistry analysis. Our study allowed for the initial identification of these proteins related to various functions in placentation with significantly altered abundance in ART groups. The present results reveal that abnormal protein profiles are involved in ART placenta and these differentially expressed proteins may be valuable for the evaluation of potential association between ART treatment and offspring outcome.

Expression and prognostic relevance of annexin A3 in prostate cancer.

OBJECTIVES: By differential quantitative protein expression, it has previously been shown that annexin A3 (ANXA3) expression is associated with prostate cancer. However little is known about the role and biology of ANXA3 in the human prostate. The aim of this study was to thoroughly analyze ANXA3 expression patterns and its potential as a prognostic marker in a large set of benign, preneoplastic, and neoplastic prostate tissue samples. METHODS: Immunohistochemistry-based ANXA3 protein expression was analyzed for 1589 prostate cancers as well as smaller subsets of benign epithelium and high-grade prostatic intraepithelial neoplasia (PIN) in a tissue microarray format. RESULTS: All samples of benign prostatic epithelium and PIN showed ANXA3 protein expression, with PIN lesions showing a decreased staining intensity compared with benign epithelium (p<0.0001). In cancer, ANXA3 protein expression was essentially reduced, resulting in a negative staining rate of 27.2%, which correlated with increasing pT stage and Gleason score (p<0.0001). ANXA3 status in cancer was shown to be an independent adverse prognostic factor and enabled substratification of the large group of intermediate-risk patients (n=969) into high- and low-risk subgroups. CONCLUSIONS: ANXA3 represents a promising candidate tissue marker, and when combined with the standard prognostic parameters, is suggested to provide a more precise prediction of prognosis in the individual patient, therefore harboring the potential to contribute to future patient management.

Annexin A3-expressing cellular phenotypes emerge from necrotic lesion in the pericentral area in 2-acetylaminofluoren/carbon tetrachloride-treated rat livers.

Recently we found a small hepatocyte-specific protein, annexin A3 (AnxA3), in fractionated adult rat hepatocytes. Here we describe the results of an in vivo demonstration of AnxA3-expressing cellular phenotypes in the liver with 2-acetylaminofluoren (2-AAF)/carbon tetrachloride (CCl(4))-injury. In association with an elevation of alanine amino transferase (ALT) and aspartic acid amino transferase (AST) activities, hepatic AnxA3 mRNA increased markedly. AnxA3-positive cells were detected in clustered cells present in or emerging from the pericentral region. These albumin-expressed cells were histologically similar to cells expressing CD34, a hematopoietic cell marker protein. The number of clusters decreased in the days following CCl(4) treatment, and annexin-negative, but albumin-positive, oval cells appeared. We concluded that the agent-induced liver defect initially recruits bone marrow-derived cells, and that it promotes differentiation of these cells into AnxA3-positive cells, followed by emergence of the oval cells, which might have a role in the restitution of the damaged liver.

[Proteomic analysis of human ovarian cancer cell lines and their platinum-resistant clones].

OBJECTIVE: To perform comparative proteomic analysis of human ovarian cancer cell lines for detecting platinum-resistance associated proteins. METHODS: The total proteins of two sensitive (SKOV3 and A2780) and four resistant (SKOV3/CDDP, SKOV3/CBP, A2780/CDDP and A2780/CBP) human ovarian cancer cell lines were separated by two-dimensional gel electrophoresis (2-DE). The differentially expressed proteins were analyzed using image analysis software, stained with Coomassie Brilliant Blue, then identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and database searching. The mRNA and protein levels of the differentially expressed protein which was most significant in all of the four resistant cell lines were validated by RT-PCR and western blotting, respectively. RESULTS: Five proteins were found to be significant in four cell lines. Annexin A3 and destrin were up-regulated and nicotinamide-adenine dinucleotide phosphate (NADP)-dependent isocitrate dehydrogenase 1 was down-regulated in all the four resistant samples. Glutathione transferase omega 1 had an increased expression in the other three resistant cell lines except for SKOV3/CBP in which its expression was not changed. However, cofilin 1 represented a different trend. In the two resistant sublines of SKOV3, cofilin 1 had a down-regulation, but it had an up-regulation in the cell lines induced from SKOV3. The expression of annexin A3 was up-regulated by 3 - 20 fold and the results of RT-PCR and western blotting showed complete consistency with that by 2-DE. CONCLUSIONS: Proteomic techniques are useful to the identification of the resistance-associated proteins in ovarian cancer platinum-resistant cell lines and five candidates have been found. The five differential proteins might become hopeful candidate biomarkers for resistance.

Expression of annexin A3 in primary cultured parenchymal rat hepatocytes and inhibition of DNA synthesis by suppression of annexin A3 expression using RNA interference.

Annexin A3 is a member of the lipocortin/annexin family, which binds to phospholipids and membranes in a Ca(2+)-dependent manner. Although annexin A3 has various functions in vitro, its cellular significance is completely unknown. Annexin A3 is not found in rat liver in vivo. In the present study, we investigated the expression of annexin A3 in primary cultured parenchymal rat hepatocytes. Annexin A3 protein was detected in 48-h, but not 2.5-h, cultured hepatocytes using Western blot analysis. The annexin A3 level further increased after an additional 24 h of culture. Annexin A3 mRNA was not detected in 2.5-h cultured hepatocytes but was detected 22 h after the start of culture by RT-PCR analysis, reaching a maximum value after 48 h of culture. To define the role of Annexin A3 in DNA synthesis, RNA interference was used to reduce annexin III gene expression in hepatocytes. The transfection of small interfering RNAs targeting annexin A3 in the hepatocytes reduced the corresponding mRNA and protein expression by approximately 80% and more than 90%, respectively, at 24 h after transfection. In the annexin A3 small interfering RNAs-transfected cells, DNA synthesis, as assessed by [3H]thymidine incorporation, decreased by approximately 70% not only in the control cultures, but also in the hepatocyte growth factor- or epidermal growth factor-treated cells. These findings show that annexin A3 is expressed in primary cultured parenchymal rat hepatocytes and that the suppression of annexin A3 expression using RNA interference inhibits DNA synthesis.

Isolated small rat hepatocytes express both annexin III and terminal differentiated hepatocyte markers, tyrosine aminotransferase and tryptophan oxygenase, at the mRNA level.

We recently showed that annexin III is expressed in isolated small rat hepatocytes but, not in parenchymal hepatocytes. In the present study, we used reverse transcription polymerase chain analysis to examine the annexin III mRNA level in isolated small rat hepatocytes and parenchymal hepatocytes. Annexin III mRNA was detected in isolated small hepatocytes, but not in isolated parenchymal hepatocytes, confirming the presence of annexin III expression in isolated small rat hepatocytes at the mRNA level and indicating that the absence of annexin III expression in isolated parenchymal hepatocytes is due to the absence of annexin III mRNA. Furthermore, we examined the mRNA level of tyrosine aminotransferase and tryptophan oxygenase, two terminally differentiated hepatocyte markers. mRNA for these markers was detected in both parenchymal hepatocytes and small hepatocytes.

Specific expression of annexin III in rat-small-hepatocytes.

Small hepatocytes are cells that express characteristic phenotypes such as a high growth potential and differentiation capacity. In order to identify rat-small-hepatocyte specific proteins, we separated the cellular proteins of isolated small and parenchymal hepatocytes by 2D polyacrylamide gel electrophoresis. Comparison of their profiles revealed a protein with a molecular mass of 37 kDa in the small hepatocytes that was not present in the parenchymal hepatocytes. Proteolytic peptide mass fingerprinting was used to identify the protein and it was found to be annexin III. The validity of the identification was confirmed by Western blot analysis with anti-annexin III antibody.