Regulation of S100A10 Gene Expression

S100A10, a member of the S100 family of Ca²⁺-binding proteins, is a widely distributed protein involved in many cellular and extracellular processes. The best recognized role of S100A10 is the regulation, via interaction with annexin A2, of plasminogen conversion to plasmin. Plasmin, together with other proteases, induces degradation of the extracellular matrix (ECM), which is an important step in tumor progression. Additionally, S100A10 interacts with 5-hydroxytryptamine 1B (5-HT1B) receptor, which influences neurotransmitter binding and, through that, depressive symptoms. Taking this into account, it is evident that S100A10 expression in the cell should be under strict control. In this work, we summarize available literature data concerning the physiological stimuli and transcription factors that influence S100A10 expression. We also present our original results showing for the first time regulation of S100A10 expression by grainyhead-like 2 transcription factor (GRHL2). By applying in silico analysis, we have found two highly conserved GRHL2 binding sites in the 1st intron of the gene encoding S100A10 protein. Using chromatin immunoprecipitation (ChIP) and luciferase assays, we have shown that GRHL2 directly binds to these sites and that this DNA region can affect transcription of S100A10.

Differential expression of Annexin 2, SPINK1, and Hsp60 predict progression of prostate cancer through bifurcated WHO Gleason score categories in African American men

BACKGROUND

Although studies have observed several markers correlate with progression of prostate cancer (PCa), no specific markers have been identified that accurately predict the progression of this disease, even in African American (AA) men who are generally at higher risk than other ethnic groups. The primary goal of this study was to explore whether three markers could predict the progression of PCa.

METHOD

We investigated protein expression of Annexin 2 (ANX2), serine peptidase inhibitor, kazal type 1(SPINK1)/tumor-associated trypsin inhibitor (TATI), and heat shock protein 60 (Hsp60) in 79 archival human prostate trans-rectal ultrasound (TRUS) biopsy tissues according to a modified World Health Organization (WHO) classification: normal (WHO1a), Gleason Score (GS6 (WHO1b), GS7 subgroups (WHO2 = 3 + 4, WHO3 = 4 + 3), GS8 (WHO4), and GS9-10 (WHO5). AA men aged 41-90 diagnosed from 1990 to 2013 at Howard University were included. Automated staining assessed expression of each biomarker. Spearman correlation assessed the direction and relationship between biomarkers, WHO and modified WHO GS, age, and 5-year survival. A two-tailed t-test and ANOVA evaluated biomarkers expression in relationship to WHO normal and other GS levels, and between WHO GS levels. A logistic and linear regression analysis examined the relationship between biomarker score and WHO GS categories. Kaplan-Meier curves graphed survival.

RESULTS

ANX2 expression decreased monotonically with the progression of PCa while expression of SPINK1/TATI and Hsp60 increased but had a more WHO GS-specific effect; SPINK1/TATI differed between normal and GS 2-6 and HSP60 differed between GS 7 and GS 2-6. WHO GS was found to be significantly and negatively associated with ANX2, and positively with SPINK1/TATI and Hsp60 expression. High SPINK1/TATI expression together with the low ANX2 expression at higher GS exhibited a bi-directional relationship that is associated with PCa progression and survival.

CONCLUSION

Importantly, the data reveal that ANX2, and SPINK1/TAT1 highly associate with WHO GS and with the transition from one stage of PrCa to the next in AA men. Future research is needed in biracial and larger population studies to confirm this dynamic relationship between ANX2 and SPINK1 as independent predictors of PCa progression in all men.

Hydrogen peroxide is a neuronal alarmin that triggers specific RNAs, local translation of Annexin A2, and cytoskeletal remodeling in Schwann cells

Schwann cells are key players in neuro-regeneration: They sense "alarm" signals released by degenerating nerve terminals and differentiate toward a proregenerative phenotype, with phagocytosis of nerve debris and nerve guidance. At the murine neuromuscular junction, hydrogen peroxide (H₂O₂) is a key signal of Schwann cells' activation in response to a variety of nerve injuries. Here we report that Schwann cells exposed to low doses of H₂O₂ rewire the expression of several RNAs at both transcriptional and translational levels. Among the genes positively regulated at both levels, we identified an enriched cluster involved in cytoskeleton remodeling and cell migration, with the Annexin (Anxa) proteins being the most represented family. We show that both Annexin A2 (Anxa2) transcript and protein accumulate at the tips of long pseudopods that Schwann cells extend upon H₂O₂ exposure. Interestingly, Schwann cells reply to this signal and to nerve injury by locally translating Anxa2 in pseudopods, and undergo an extensive cytoskeleton remodeling. Our results show that, similarly to neurons, Schwann cells take advantage of local protein synthesis to change shape and move toward damaged axonal terminals to facilitate axonal regeneration.

Comprehensive protein profiling of synovial fluid in osteoarthritis following protein equalization

OBJECTIVE

The aim of the study was to characterise the protein complement of synovial fluid (SF) in health and osteoarthritis (OA) using liquid chromatography mass spectrometry (LC-MS/MS) following peptide-based depletion of high abundance proteins.

DESIGN

SF was used from nine normal and nine OA Thoroughbred horses. Samples were analysed with LC-MS/MS using a NanoAcquity™ LC coupled to an LTQ Orbitrap Velos. In order to enrich the lower-abundance protein fractions protein equalisation was first undertaken using ProteoMiner™. Progenesis-QI™ LC-MS software was used for label-free quantification. In addition immunohistochemistry, western blotting and mRNA expression analysis was undertaken on selected joint tissues.

RESULTS

The number of protein identifications was increased by 33% in the ProteoMiner™ treated SF compared to undepleted SF. A total of 764 proteins (462 with≥2 significant peptides) were identified in SF. A subset of 10 proteins were identified which were differentially expressed in OA SF. S100-A10, a calcium binding protein was upregulated in OA and validated with western blotting and immunohistochemistry. Several new OA specific peptide fragments (neopeptides) were identified.

CONCLUSION

The protein equalisation method compressed the dynamic range of the synovial proteins identifying the most comprehensive SF proteome to date. A number of proteins were identified for the first time in SF which may be involved in the pathogenesis of OA. We identified a distinct set of proteins and neopeptides that may act as potential biomarkers to distinguish between normal and OA joints.

Down-regulation of Ras-related protein Rab 5C-dependent endocytosis and glycolysis in cisplatin-resistant ovarian cancer cell lines

Drug resistance poses a major challenge to ovarian cancer treatment. Understanding mechanisms of drug resistance is important for finding new therapeutic targets. In the present work, a cisplatin-resistant ovarian cancer cell line A2780-DR was established with a resistance index of 6.64. The cellular accumulation of cisplatin was significantly reduced in A2780-DR cells as compared with A2780 cells consistent with the general character of drug resistance. Quantitative proteomic analysis identified 340 differentially expressed proteins between A2780 and A2780-DR cells, which involve in diverse cellular processes, including metabolic process, cellular component biogenesis, cellular processes, and stress responses. Expression levels of Ras-related proteins Rab 5C and Rab 11B in A2780-DR cells were lower than those in A2780 cells as confirmed by real-time quantitative PCR and Western blotting. The short hairpin (sh)RNA-mediated knockdown of Rab 5C in A2780 cells resulted in markedly increased resistance to cisplatin whereas overexpression of Rab 5C in A2780-DR cells increases sensitivity to cisplatin, demonstrating that Rab 5C-dependent endocytosis plays an important role in cisplatin resistance. Our results also showed that expressions of glycolytic enzymes pyruvate kinase, glucose-6-phosphate isomerase, fructose-bisphosphate aldolase, lactate dehydrogenase, and phosphoglycerate kinase 1 were down-regulated in drug resistant cells, indicating drug resistance in ovarian cancer is directly associated with a decrease in glycolysis. Furthermore, it was found that glutathione reductase were up-regulated in A2780-DR, whereas vimentin, HSP90, and Annexin A1 and A2 were down-regulated. Taken together, our results suggest that drug resistance in ovarian cancer cell line A2780 is caused by multifactorial traits, including the down-regulation of Rab 5C-dependent endocytosis of cisplatin, glycolytic enzymes, and vimentin, and up-regulation of antioxidant proteins, suggesting Rab 5C is a potential target for treatment of drug-resistant ovarian cancer. This constitutes a further step toward a comprehensive understanding of drug resistance in ovarian cancer.

Annexin A2 in renal cell carcinoma: expression, function, and prognostic significance

OBJECTIVE

Renal cell carcinoma (RCC) is the most lethal genitourinary cancer and intrinsically resistant to chemotherapy, radiotherapy, and hormone therapy. Annexin A2 (Anxa2) is a calcium-dependent phospholipid-binding protein found on various cell types that plays multiple roles in regulating cellular functions. In RCC, Anxa2 expression was correlated with tumor differentiation, clinical outcomes, and the metastatic potential; however, the underlying mechanisms remain obscure. This study investigated the role of Anxa2 in regulating tumorigenesis of RCC.

MATERIALS AND METHODS

Commercial RCC tissue microarray arrays and a kidney cancer quantitative polymerase chain reaction array were used to examine Anxa2 by immunohistochemistry and real-time polymerase chain reaction analysis. Short hairpin (sh)RNA-based lentiviral system technology was used to evaluate the effects of manipulating Anxa2 expression on multiple malignant features of 2 RCC cell lines, A498 and 786-O, and its mechanisms.

RESULTS

(1) The Anxa2 expression level was generally elevated to varying degrees in RCC tissues. In adjacent noncancerous tissues, Anxa2 was mainly expressed in glomeruli and slightly expressed in the cytoplasm of proximal tubules. (2) An increased Anxa2 expression level was found in tissues of clear cell RCC, papillary RCC, and chromophobe RCC, and it was prominently expressed in cancer cell membranes. In addition, the Anxa2 expression level was correlated with poor prognosis. (3) Silencing Anxa2 expression suppressed the abilities of cell migration and invasion, but cell proliferation was less affected. (4) Diminished Anxa2 expression caused alterations in the cell polarity, disrupted the formation of actin filaments, and reduced CXCR4 expression. (5) Inhibition of the Rho/Rock axis restored silencing of Anxa2-mediated suppression of cell motility.

CONCLUSIONS

Overall, our study points out the regulatory function of Anxa2 in RCC cell motility and provides a molecular-based mechanism of Anxa2 positivity in the progression of RCC.

Identification of a tumour associated antigen in lung cancer patients with asbestos exposure

BACKGROUND

This study analysed the humoral immune response in asbestos exposed lung cancer patients to identify new surrogate markers of the carcinogenic risk in populations exposed to asbestos.

METHODS AND RESULTS

A serological analysis identified five distinct antigens reactive with IgG derived from a lung cancer patient with high asbestos exposure. In one of the isolated antigens, quantitative RT-PCR indicated that annexin A2 (AnxA2) was overexpressed in lung cancer tissues and normal lung from patients with high asbestos exposure. Antibody against AnxA2 was detected in 9/15 (60%) of lung cancer patients with high asbestos exposure; however, in only 1/12 (8%) of lung cancer patients with low asbestos exposure. AnxA2 was also overexpressed in malignant mesothelioma cells, and the antibody was also positive in 8/15 (53%) of patients with malignant mesothelioma.

CONCLUSION

The antibody titer against AnxA2 may be a potentially useful new diagnostic surrogate marker for asbestos-related lung cancer and malignant mesothelioma.

[Interferon-gamma decreases the adhesiveness and invasiveness of prostate cancer cells]

OBJECTIVE

To study the effects of interferon-gamma (IFN-gamma) on the adhesiveness and invasiveness of prostate cancer cells.

METHODS

We determined the effect of IFN-gamma on the adhesiveness of prostate cancer cell lines LNCaP and PC-3 by treating the plate with fibronectin and laminin, on the invasiveness of prostate cancer cells into the artificial basal membrane consisting of Matrigel and fibronectin using the Transwell chamber, and on the expression of annexin-2 in these cells by Western blot.

RESULTS

The adhesion rates of prostate cancer cell lines LNCaP and PC-3 were 21% and 23% in the IFN-gamma treatment group, significantly lower than 46% and 40% in the untreated group (P < 0.05). The invasiveness of the cells was markedly decreased in the former as compared with the latter (P < 0.05). IFN-gamma significantly inhibited the expression of annexin-2 in prostate cancer cell lines LNCaP and PC-3 (P < 0.05).

CONCLUSION

IFN-gamma can decrease the adhesiveness and invasiveness of the prostate cancer cell line by down-regulating the expression of annexin-2.

S100A10 expression in thyroid neoplasms originating from the follicular epithelium: contribution to the aggressive characteristic of anaplastic carcinoma

BACKGROUND

S100A10, a member of the S100 family, forms a heterotetramer with annexin IIH and promotes carcinoma invasion and metastasis by plasminogen activation. In this study, S100A10 and annexin II expression in thyroid neoplasms were demonstrated.

PATIENTS AND METHODS

The expression levels of S100A10 and annexin II in 193 thyroid neoplasms were immunohistochemically investigated.

RESULTS

S10A10 and annexin II were not expressed in normal follicular cells or any follicular adenomas. Cells stained positively in 14.6% and 20.8% of follicular carcinomas for S100A10 and annexin II, respectively, but their expression levels were always low. S100A10 and annexin II were expressed in all papillary carcinomas, but 88.2% and 82.8% ofpapillary carcinomas were classified in the low group. These expression levels were not linked to any clinicopathological features. S100S10 and annexin II were also expressed in all anaplastic carcinomas, with 83.3% of these lesions were classified in the high group.

CONCLUSION

These findings suggest that S100A10 and annexin II contribute to the aggressive characteristics of anaplastic carcinoma, while playing a constitutive role in papillary carcinoma.

[Dysregulation of Annexin II expression in esophageal squamous cell cancer and adjacent tissues from a high-incidence area for esophageal cancer in Henan province]

BACKGROUND & OBJECTIVE

Our recent study on proteomics for esophageal cancer has indicated the importance of Annexin II as a promising protein to distinguish esophageal cancer patients from healthy subjects. This study was to detect the expression of Annexin II in esophageal squamous cell carcinoma (ESCC) and adjacent tissues, and to explore the role of Annexin II in ESCC pathogenesis and mechanisms.

METHODS

The expression of Annexin I in 33 specimens of ESCC and adjacent tissues from Linzhou, a high-incidence area for esophageal cancer in Henan province, was detected by ABC immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

Annexin II protein was expressed in 90.6% normal esophageal epithelium and decreased with ESCC progression. In carcinoma in situ (CIS), 50.0% foci lost Annexin II protein expression. The expression of Annexin II protein was increased in well differentiated SCC and decreased with loss of differentiation of SCC. In poorly differentiated SCC, 45.4% foci lost Annexin II protein expression. However, RT-PCR did not detect differential expression of Annexin II mRNA between normal esophageal epithelium and CIS.

CONCLUSIONS

Elevated or reduced expression of Annexin II may be correlated to reverse or progression of carcinogenesis respectively, and Annexin II may be another candidate biomarker for screening of high-risk subjects and early diagnosis of SCC.

[Annexin A2 expression in head and neck squamous cell carcinoma]

OBJECTIVE

Over-expression of annexin A2 (ANXA2) has been reported in various cancers. However, no data are available on the expression of this protein in head and neck squamous cell carcinomas (HNSCC). The objective of this preliminary study is to investigate the expression of ANXA2 in these carcinomas.

MATERIAL AND METHOD

ANXA2 expression was analyzed by immunohistochemistry in paraffin-embedded sections from 9 patients with premalignant lesions and 21 patients with HNSCC.

RESULTS

All dysplastic tissues showed significantly reduced ANXA2 expression compared to normal tissue. In contrast, ANXA2 expression was observed in all but one of the tumours studied. There was a significant correlation of lower ANXA2 expression with a poorer histological differentiation, larger tumours, and nodal metastases.

CONCLUSIONS

Our data show for the first time that ANXA2 is expressed in head and neck squamous cell carcinomas and that its expression seems to be related with the degree of differentiation status of these tumours.

Evaluation of S100A10, annexin II and B-FABP expression as markers for renal cell carcinoma

This study aimed to analyze expression of S100A10, annexin II and B-FABP genes in renal cell carcinoma (RCC) and their potential value as tumor markers. Furthermore, any correlation between the gene expression and prognostic indicators of RCC was analyzed. Expression of each gene was estimated by RT-PCR in the non-neoplastic (normal) and tumorous parts of resected kidney samples. Also, each antigen was immunostained in RCC and normal kidney tissues. Expression of the S100A10 gene averaged 2.5-fold higher in the tumor than that in the normal tissues (n = 47), after standardization against that of beta-actin. However, expression of annexin II, a natural ligand of S100A10, was only 1.64-fold higher. In the tissue sections of RCC, S100A10 and annexin II were immunostained in membranes. In the normal renal epithelia, however, both antigens were stained in the Bowman's capsule and the tubules from Henle's loop through the collecting duct system, but not in the proximal tubules, from where most RCC are derived. In contrast, expression of the B-FABP gene was 20-fold higher in the tumor. No B-FABP was immunohistochemically detected in normal kidney sections, but it was stained in the cytoplasm of RCC tissue sections. S100A10 and B-FABP genes were overexpressed regardless of nuclear grade and stage of RCC. Immunopositivity in RCC tissues (n = 13) was 100% for S100A10 and annexin II, and 70% for B-FABP; however, no clear relationship was observed in either antigen with nuclear grade and stage. It was found that all three performed well as RCC markers. B-FABP was most specific to RCC, as it was expressed little in normal kidney tissues.

Expression of annexin A2 in GABAergic interneurons in the normal rat brain

Expression of the Ca(2+)-dependent phospholipids binding protein annexin A2 (ANX2) in the brain is thought to be largely associated with brain pathological conditions such as tumor, inflammation, and neurodegeneration. The recent findings that ANX2 heterotetramer is involved in learning and neuronal activities necessitates a systematic investigation of the physiological expression of ANX2 in the brain. With combination of in situ hybridization and immunohistochemistry, ANX2 mRNA and protein were specifically detected in a group of GABAergic interneurons throughout the brain. Although ANX2 was absent from the interior of pyramidal neurons, it was found on the membrane and seemly the extracellular space of those neurons, where they closely co-localized with glutamate decarboxylase terminals. In cultured developing neurons, ANX2 was present at high concentrations in the growth cones co-distributing with several growth-associated proteins such as growth associated protein 43 (GAP43), turned on after division/Ulip/CRMP (TUC-4), tubulin, and tissue-plasminogen activator. It then became predominantly distributed on the membrane and mostly in axonal branches as neurons grew and extended synaptic networks. ANX2 was also secreted from cultured neurons, in a membrane-bound form that was Ca(2+)-dependent, which was significantly increased by neuronal depolarization. These results may have implications in the function and regulatory mechanism of ANX2 in the normal brain.

Deletion of annexin 2 light chain p11 in nociceptors causes deficits in somatosensory coding and pain behavior

The S100 family protein p11 (S100A10, annexin 2 light chain) is involved in the trafficking of the voltage-gated sodium channel Na(V)1.8, TWIK-related acid-sensitive K+ channel (TASK-1), the ligand-gated ion channels acid-sensing ion channel 1a (ASIC1a) and transient receptor potential vanilloid 5/6 (TRPV5/V6), as well as 5-hydroxytryptamine receptor 1B (5-HT1B), a G-protein-coupled receptor. To evaluate the role of p11 in peripheral pain pathways, we generated a loxP-flanked (floxed) p11 mouse and used the Cre-loxP recombinase system to delete p11 exclusively from nociceptive primary sensory neurons in mice. p11-null neurons showed deficits in the expression of Na(V)1.8, but not of annexin 2. Damage-sensing primary neurons from these animals show a reduced tetrodotoxin-resistant sodium current density, consistent with a loss of membrane-associated Na(V)1.8. Noxious coding in wide-dynamic-range neurons in the dorsal horn was markedly compromised. Acute pain behavior was attenuated in certain models, but no deficits in inflammatory pain were observed. A significant deficit in neuropathic pain behavior was also apparent in the conditional-null mice. These results confirm an important role for p11 in nociceptor function.

[The fibrinolytic activity in leukemic cell lines and its alteration on all-trans retinoic acid treatment]

OBJECTIVES

To study the fibrinolytic activity and the expression of uPAR and Annexin II in leukemic cell lines and their alterations on all-trans retinoic acid ( ATRA) treatment.

METHODS

The fibrinolytic activity was measured by chromogenic assay in NB4, SHI-1, K562, Jurkat and Raji cell lines. The protein expression of uPAR and Annexin II on cells surface and the mRNA expression of uPAR and Annexin II in cells of these cell lines were detected using flow cytometry and RT-PCR method respectively.

RESULTS

The plasmin activity in supernatant was increased significantly after incubation of SHI-1 and NB4 cells with plasminogen. The plasmin activity of NB4 cells was obviously decreased by ATRA. The plasmin activity of NB4 and SHI-1 cells was significantly decreased by uPAR monoclonal antibodies. The expressions of uPAR and Annexin II and their mRNA in SHI-1 and NB4 cells were higher than that in other cell lines. ATRA could remarkably decrease the expressions of Annexin II and uPAR and their mRNA in NB4 cells.

CONCLUSION

In leukemia cell lines, NB4 and SHI-1 cells have stronger fibrinolytic activity. Both Annexin II and uPAR on the leukemic cell membranes might contribute to this activity. The high fibrinolytic activity can be corrected by ATRA by down-regulating Annexin I and uPAR mRNA and protein expression in NB4 cells.

Role of annexin II in estrogen-induced macrophage matrix metalloproteinase-9 activity: the modulating effect of statins

Annexin II (ANXII) is a receptor for tissue plasminogen activator and plasminogen for the conversion to plasmin, which, in turn, induces metalloproteinase-9 (MMP-9). 17beta-Estradiol (E(2)) is reported to decrease plasminogen activity inhibitor-1 and increase plasmin and matrix metalloproteinase activity. However, the combined effects of estrogen and statins on macrophage MMP-9 activity and ANXII expression remain unclear. Treatment of J774A.1 macrophages with 1.0-100 nM of E(2) for 24h increased both MMP-9 activity and ANXII expression in a dose-dependent manner (p<0.05). Preincubation with EGTA (10mM) released ANXII from the cell membrane and inhibited the E(2)-mediated MMP-9 activity as did incubation of macrophages with anti-annexin IgG. In the presence or absence of E(2) (5 nM), simvastatin treatment in the range of 0.1-5.0 microM significantly reduced macrophage MMP-9 enzymatic activity (p<0.005) in a dose-dependent manner. In the presence or absence of E(2), simvastatin also decreased ANXII expression (p<0.05). These findings indicate that ANXII plays a central role in modulating the enzymatic activity of MMP-9 in response to E(2) and that E(2)-mediated ANXII expression and MMP-9 activity can be prevented by simvastatin. Prevention of E(2)-mediated activation of MMP-9 by simvastatin suggests that concurrent statin use may account for early event risk of myocardial infarction seen with hormone therapy in recent clinical trials.

Tissue plasminogen activator in murine exocrine pancreas cancer: selective expression in ductal tumors and contribution to cancer progression

Tissue plasminogen activator (tPA) is absent from normal human pancreas and is expressed in 95% of human pancreatic adenocarcinomas. We have analyzed the expression of components of the tPA system in murine pancreatic tumors and the role of tPA in neoplastic progression. Transgenic mice expressing T antigen and c-myc under the control of the elastase promoter (Ela1-TAg and Ela1-myc, respectively) were used. tPA was undetectable in normal pancreas, acinar dysplasia, ductal complexes, and in all acinar tumors. By contrast, it was consistently detected in Ela1-myc tumors showing ductal differentiation. Crossing transgenic Ela1-myc with tPA-/- mice had no effect on the proportion of ductal tumors, indicating that tPA is not involved in the acinar-to-ductal transition. Ela1-myc:tPA-/- mice showed an increased survival in comparison to control mice. All ductal tumors, and none of the acinar tumors, overexpressed the tPA receptor annexin A2, suggesting its participation in the effects mediated by tPA. Our findings indicate that murine and human pancreatic ductal tumors share molecular alterations in the tPA system that may play a role in tumor progression.

Gene silencing in alveolar type II cells using cell-specific promoter in vitro and in vivo

RNA interference (RNAi) is a sequence-specific post-transcriptional gene silencing process. Although it is widely used in the loss-of-function studies, none of the current RNAi technologies can achieve cell-specific gene silencing. The lack of cell specificity limits its usage in vivo. Here, we report a cell-specific RNAi system using an alveolar epithelial type II cell-specific promoter--the surfactant protein C (SP-C) promoter. We show that the SP-C-driven small hairpin RNAs specifically depress the expression of the exogenous reporter (enhanced green fluorescent protein) and endogenous genes (lamin A/C and annexin A2) in alveolar type II cells, but not other lung cells, using cell and organ culture in vitro as well as in vivo. The present study provides an efficient strategy in silencing a gene in one type of cell without interfering with other cell systems, and may have a significant impact on RNAi therapy.

Upregulation of annexins I, II, and V after traumatic spinal cord injury in adult rats

The posttraumatic inflammatory reaction contributes to progressive tissue damage after spinal cord injury (SCI). Annexins, a family of structurally related calcium- and phospholipid-binding proteins, have potent anti-inflammatory effects by inhibiting the activity of phospholipase A(2) (PLA(2)), a key enzyme responsible for inflammation and cytotoxicity. We investigated spatiotemporal expression of annexins I, II, and V after a contusive SCI using the New York University impact device (a 10-g rod, height 12.5 mm) in adult rats. Western blot analysis revealed that annexin I expression increased at 3 days after injury, peaked at 7 days (1.75-fold above the baseline level; P < 0.01), started to decline at 14 days, and returned to the baseline level at and beyond 28 days post-injury. The expression of annexin II started to increase at 3 days, reached its maximal level at 14 days (2.73-fold; P < 0.01), remained at a high level up to 28 days, and then declined to the basal level by 56 days after injury. Annexin V expression started at 3 days, reached its maximal level at 7 days (1.61-fold; P < 0.05) and remained at this level until 56 days after injury. RT-PCR results confirmed expression of all three annexins at the mRNA level after SCI. Immunohistochemistry and immunofluorescence double-labeling analyses revealed that increased annexins I, II, and V were localized in neurons and glial cells. The present study thus revealed increased expression of the three annexin isoforms after moderate contusive SCI. The precise role of annexins in posttraumatic inflammation and neuroprotection after SCI remains to be determined.

Analysis of gene expressions of T cells from children with acute exacerbations of asthma

BACKGROUND

Little is known about airway inflammation in childhood asthma. The aims of this study were to analyze the expression of a wide range of mediators of airway inflammation in childhood asthma.

METHODS

Eight asthmatic children with acute exacerbations were recruited for the study. Peripheral blood was drawn from the patients at the time of exacerbation and after improvement. Total RNA was extracted from the isolated T lymphocytes. The differential display (DD) RT-PCR method was used to detect expressed genes, and the quantification of candidate gene expression was performed using real-time quantitative RT-PCR.

RESULTS

The only gene for which significant expression differences were detected in both DD analysis and quantitative RT-PCR was lipocortin II (annexin II) (exacerbation > remission, p < 0.05). In quantitative RT-PCR of interleukin-4 (IL-4), IL-5, interferon-gamma, IL-12 receptor-beta and integrin alpha6, a significant difference was found only in the expression of IL-4 mRNA (exacerbation > remission, p < 0.05). The IL-4 plasma concentration tended to be higher in exacerbation than in remission.

CONCLUSIONS

Our findings suggest activation of T cells and IL-4 production may be involved not only in the basic pathogenesis of childhood asthma but also in its acute exacerbation, and that lipocortin II may be a marker or contribute to asthma exacerbation.

Heat shock protein 90alpha-dependent translocation of annexin II to the surface of endothelial cells modulates plasmin activity in the diabetic rat aorta

The goals of this article were (1) to identify cell surface proteins whose expression was regulated by diabetes and (2) to assess their contribution to diabetic complications. We purified heat shock protein 90alpha (Hsp90alpha) from the membrane fraction of high glucose-treated endothelial cells (ECs) as a binding partner for a diabetes-specific phage. Further investigation revealed that high glucose elevated cell surface Hsp90alpha in cultured cells, and that diabetes increased the amount of Hsp90alpha on the luminal surface of the aorta. We also found that high glucose or diabetes promoted the association of Hsp90alpha with annexin II and increased the expression of annexin II on the surface of aortic ECs. Finally, plasmin activity was increased by high glucose or diabetes, and this change was partially reversed with an annexin II antibody. These findings reveal a novel glucose-regulated interaction between Hsp90alpha and annexin II, and raise the possibility that increased expression of annexin II, which promotes the generation of plasmin, is linked to clotting abnormalities associated with the diabetic state.

5-Fluorouracil: identification of novel downstream mediators of tumour response

BACKGROUND

5-Fluorouracil (5-FU) is routinely used in the treatment of gastrointestinal, breast and head and neck cancers. A major limitation to the use of this drug is acquired or inherent resistance.

MATERIALS AND METHODS

To examine the downstream molecular signals activated in response to 5-FU, we used DNA microarray technology to examine global transcriptional changes in 5-FU-treated MCF-7 breast cancer cells.

RESULTS

We identified several novel 5-FU-inducible target genes that have not previously been linked to 5-FU response, including spermine/spermidine acetyl transferase (SSAT) and annexin II. Treatment of MCF-7 cells with the antifolate tomudex (TDX) and the DNA damaging agent oxaliplatin also caused up-regulation of each target gene. Inactivation of wild-type p53 abrogated the 5-FU-mediated induction of SSAT and annexin II. Inducible expression of thymidylate synthase completely abrogated TDX-, but not 5-FU-mediated induction of each gene. Furthermore, basal expression of SSAT and annexin II was elevated in cells resistant to 5-FU.

CONCLUSION

These data demonstrate the potential of microarray analysis to identify novel genes associated with response or resistance to chemotherapeutic agents.

Expression of Annexin I, II and VII Proteins in Androgen Stimulated and Recurrent Prostate Cancer

PURPOSE

We performed a comprehensive survey of annexin I, II and VII protein expression in patient matched benign prostatic epithelium (BPE), androgen stimulated prostate cancer (AS-CaP) and recurrent prostate cancer (R-CaP).

MATERIALS AND METHODS

Annexin I, II and VII was immunostained in 23 matched pairs of BPE and AS-CaP specimens, and in 25 R-CaP specimens. Protein expression was assessed visually and using color digital video image analysis.

RESULTS

The expression levels of annexins I and II was decreased from BPE to AS-CaP in all patients examined using visual assessment (22 of 22) or digital image analysis (18 of 18 for annexin I and 22 of 22 for annexin II). Annexin I mean optical density (MOD) decreased by 69% (0.718 to 0.222, p <0.0001) and annexin II MOD decreased by 71% (0.820 to 0.238, p <0.0001). Annexin I MOD further decreased almost 50% in R-CaP compared with AS-CaP (0.117 vs 0.222, p <0.0065) and annexin II MOD further declined by 37% (AS-CaP 0.238 vs R-CaP 0.150, p <0.0001). Annexin VII MOD showed no significant change between BPE and AS-CaP (0.229 and 0.214, respectively) but it decreased 14% in R-CaP vs AS-CaP (0.184 vs 0.214, p <0.0051).

CONCLUSIONS

Annexins I and II expression are decreased in AS-CaP compared with BPE and a further reduction is observed with progression from AS-CaP to R-CaP. Annexin VII protein expression is decreased in R-CaP, although AS-CaP and BPE are similar. This study suggests that the dysregulations of annexin proteins I, II and VII are important events in prostate carcinogenesis and progression.

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.

Molecular responses of human muscle to eccentric exercise

We examined the effect of eccentric exercise on the transcriptome of skeletal muscle in three male human volunteers who performed 300 concentric contractions with one leg and 300 eccentric contractions with the opposite leg. Vastus lateralis muscle biopsies were taken from both legs at 4-8 h after exercise, and expression was profiled by using 12000 gene Affymetrix U95Av2 microarrays. We found a high concordance of expression responses to eccentric contractions between our human and rat data from a previous study (Chen YW, Nader GA, Baar KR, Fedele MJ, Hoffman EP, and Esser KA. J Physiol 545: 27-41, 2002) ( approximately 50% of gene expression changes shared between species). Potential human-specific changes included greater inflammatory responses [chemokine (C-C motif) ligand 2, C/EBP delta, and IL-1 receptor] and vascular remodeling (tenascin C and lipocortin II). Induction of c-fos and lipocortin II were confirmed at the protein level, with c-fos localized to myofiber nuclei and lipocortin II to intramuscular capillaries. We also confirmed the eccentric-induced expression of six transcripts by quantitative RT-PCR (cardiac ankyrin-repeated protein, chemokine ligand 2, CCAAT/enhancer binding protein delta, IL-1 receptor, tenascin C, and cysteine-rich angiogenic inducer 61). These data provide the first characterization of the transcriptional response of skeletal muscle to eccentric exercise in humans and represent a preliminary step in understanding the molecular processes underlying muscle remodeling (including a new focus on rapid changes in the capillary bed) and inflammatory responses after damaging lengthening contractions.

[Expression of annexin II in human esophageal squamous cell carcinoma]

OBJECTIVE

To evaluate the expression of annexin II in human esophageal squamous cell carcinoma (ESCC) and its relation with clinicopathological data.

METHODS

The expression of annexin II mRNA and protein in paired cancer tissues and their adjacent quasi-normal tissues were detected by RT-PCR, immunohistochemical method and densitometric scanning. The relation between annexin II expression and the status of tumor differentiation was analyzed.

RESULTS

The expression of annexin II was significantly lower in the tumor tissue than that in its paired normal counterpart both in mRNA and protein level (P < 0.05, P < 0.01). The protein expression of annexin II was significantly lower in moderately and poorly differentiated tumors than those in well differentiated ones (P < 0.05).

CONCLUSION

Down-regulation of annexin II in esophageal carcinogenesis may play an important role in squamous cell differentiation.

Expression of a releasable form of annexin II by human keratinocytes

Annexin II is a multifunctional calcium-dependent phospholipid binding protein whose presence in epidermis has previously been reported. However, like other members of annexin family, annexin II has been regarded as either an intracellular protein or associated with the cellular membrane. Here, we report the presence of a releasable annexin II and p11, two monomers of annexin II tetramer, in keratinocyte-conditioned medium (KCM). Proteins present in KCM were fractionated on a gel filtration column and following further evaluation, a releasable protein with apparent MW of 36 kDa was identified. Further characterization identified this protein as the p36 monomer of annexin II tetramer. The phospho-tyrosine antibody did not visualize this protein as the phosphorylated form of p36. Several experiments were conducted to examine whether this protein is soluble or associated with keratinocyte cell membranes in the conditioned medium. A centrifugation of conditioned medium was not able to bring this protein down into the pellet. Surprisingly, the results of Western analysis identified p36 and p11, two monomers of the annexin II tetramer, in conditioned medium derived from either keratinocytes cultured alone or keratinocytes co-cultured with fibroblasts. In contrast to the keratinocyte-conditioned medium in which annexin II was easily detectable, both monomers were barely detectable in conditioned medium collected from dermal fibroblasts. This finding was in contrast to the cell lysates in which p36 was detectable in both keratinocytes and fibroblasts. However, the amount of this protein was markedly higher in keratinocyte lysate relative to that of dermal fibroblasts. Conditioned medium derived from keratinocyte established from adult showed a higher level of annexin II compared to that of keratinocytes established from newborn babies. The expression of p11 seems to increase with differentiation of keratinocytes derived from either adult or newborn skin samples. When the site of annexin synthesis in human skin was examined by immunohistochemical staining, the antibody for p36 localized the annexin to the keratinocyte cell members in the basal and suprabasal keratinocytes. In conclusion, Western blot detection of both p36 and p11 in conditioned medium from skin cells revealed that human keratinocytes, but not fibroblasts, express a releasable monomer form of annexin II which is regulated by differentiation status of keratinocytes. This finding is consistent with the localization of annexin II detected by immunohistochemical staining.

Loss of annexin II heavy and light chains in prostate cancer and its precursors

Annexin II mRNA coding for a calcium binding protein was found to be absent in prostate cancer by subtractive hybridization and Northern analysis. In contrast to high expression in normal and benign hyperplastic glandular and basal epithelium, Annexin II heavy (p36) and light (p11) chains in 31/31 prostate cancer specimens were lost immunohistochemically. In glands involved by prostate intraepithelial neoplasia, 65% lost both chains in glandular epithelial cells, whereas basal cells were all positively stained. Southern analysis of cancer DNA showed no noticeable deletion in p36 gene. LNCaP cells treated with 5-azacytidine re-expressed p36, suggesting methylation could be responsible for the silencing.

Functional proteomics: examining the effects of hypoxia on the cytotrophoblast protein repertoire

The outcome of human pregnancy depends on the differentiation of cytotrophoblasts, specialized placental cells that physically connect the embryo/fetus to the mother. As cytotrophoblasts differentiate, they acquire tumor-like characteristics that enable them to invade the uterus. In a novel feedback loop, the increasingly higher levels of oxygen they encounter within the uterine wall influence their differentiation into vascular-like cells. Together, the invasive and cell surface properties of cytotrophoblasts enable them to form vascular connections with uterine blood vessels that divert maternal blood flow to the placenta, a critical hurdle in pregnancy. It is therefore important to understand how cytotrophoblasts respond to changes in oxygen tension. Here we used a proteomics approach, two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) combined with mass spectrometry, to characterize the protein repertoire of first trimester human cytotrophoblasts that were maintained under standard tissue culture conditions (20% O(2)). 2-D PAGE showed a unique protein map as compared to placental fibroblasts and human JEG-3 choriocarcinoma cells. Mass spectrometry allowed the identification of 43 spots on the cytotrophoblast map. Enzymes involved in glycolysis and responses to oxidative stress, as well as the 14-3-3 signaling/adapter proteins, were particularly abundant. Hypoxia in vitro (2% O(2)) produced discrete changes in the expression of a subset of proteins in all the aforementioned functional categories. Together, these data offer new information about the early gestation cytotrophoblast protein repertoire and the generalized mechanisms the cells use to respond to changes in oxygen tension at the maternal-fetal interface.

Annexin II overexpression is correlated with poor prognosis in human gastric carcinoma

Annexins belong to a family of the calcium-dependent phospholipid binding proteins. They are also substrates of receptor tyrosine kinases. Overexpression of Annexin II, which has been reported in various carcinomas, is thought to be associated with cell proliferation, differentiation and cell-cell adhesion in the pathogenesis of carcinoma, but the functions of Annexins have not been fully elucidated. In this study, we investigated the role of Annexin II (p36) and its relationship with c-erbB-2 overexpression in gastric carcinoma. We studied Annexin II expression using Western blot analysis in 8 human gastric carcinoma cell lines and expression of Annexin II and c-erbB-2 using, immunohistochemistry in 153 primary gastric carcinomas. Western blot revealed that Annexin II was expressed in 8 human gastric carcinoma cell lines. It was more strongly expressed in the cell membrane than in the cytoplasm of tumor cells in primary gastric carcinoma tissues. Thirty-three percent of all cases were immunopositive for Annexin II, overexpression of which was more frequent in differentiated type (p = 0.0009), lymph node, metastasis (p = 0.0147) and venous invasion (p = 0.0092). Annexin II and c-erbB-2 overexpression were significantly correlated p = 0.0002) and patients with Annexin II had poorer prognoses (p = 0.0066). Multivariate analysis showed that immunopositivity of both Annexin II and c-erbB-2 was an independent and poor prognostic factor (p = 0.0037). In conclusion, Annexin II was overexpressed in advanced gastric carcinomas and it could contribute to the progression of gastric carcinoma.

Nickel-induced proteins in human HaCaT keratinocytes: annexin II and phosphoglycerate kinase

It has been established in previous in vitro experiments with human HaCaT keratinocytes that nickel becomes cytotoxic at concentrations higher than 100 microM and that it is accumulated mainly in the cytosolic fraction (Ermolli et al., 2000). The aim of this work was to search possible biomarkers of metal insult, i.e. nickel-binding proteins or proteins differentially expressed in the cytosolic fraction of nickel-exposed cells (up to 1 mM nickel) as compared to controls. Cytosolic proteins were studied by isoelectric focusing (IEF) and two-dimensional gel electrophoresis (2-DE). Separation by IEF revealed nickel-induced changes in the abundance of cytosolic proteins as visualised with nickel-nitrilo-triacetic-alkaline phosphatase (Ni-NTA-AP) in blots. The cytosolic fraction of cells incubated with nickel, at concentrations over 100 microM, showed nickel binding components which were absent or present in significantly lower amounts in control cells. These proteins had isoelectric points (pIs) 6.9, 7.7 and 8.5. After 2-DE silver- and protein staining significantly increased abundance of four proteins was observed. Their pI values corresponded to those of the nickel binding ones seen after IEF. A protein with pI 6.9 had a molecular weight estimated to 38 kDa, two proteins with pI around 7.7 showed molecular weights of 57 and 22 kDa, respectively and another protein with pI of 8.5 had a molecular weight of 33 kDa. The increased abundance of these components, both in IEF experiments and in 2-DE, correlated with the nickel concentration in the culture media. N-terminal amino acid sequencing and database search allowed identification of one a protein as phosphoglycerate kinase and another one as annexin II. The involvement of these proteins in cellular functions and their possible implications in the mechanism of nickel toxicity in keratinocytes are discussed. Some of these proteins may be biomarker candidates for effects of nickel exposure in human keratinocytes.

Modes of annexin-membrane interactions analyzed by employing chimeric annexin proteins

Annexin II is a member of the annexin family of Ca(2+)- and phospholipid-binding proteins which is particularly enriched on early endosomal membranes and has been implicated in participating in endocytic events. In contrast to other endosomal annexins the association of annexin II with its target membrane can occur in the absence of Ca(2+) in a manner depending on the unique N-terminal domain of the protein. However, endosome binding of annexin II does not require formation of a protein complex with the intracellular ligand S100A10 (p11) as an annexin II mutant protein (PM AnxII) incapable of interacting with p11 is still present on endosomal membranes. Fusion of the N-terminal sequence of this PM AnxII (residues 1-27) to the conserved protein core of annexin I transfers the capability of Ca(2+)-independent membrane binding to the otherwise Ca(2+)-sensitive annexin I. These results underscore the importance of the N-terminal sequence of annexin II for the Ca(2+)-independent endosome association and argue for a direct interaction of this sequence with an endosomal membrane receptor.

The annexinopathies: a new category of diseases

The annexins are a family of highly homologous phospholipid binding proteins, which share a four-domain structure, with one member of the family - annexin VI - having a duplication consisting of eight domains. Thus far, ten annexins have been described in mammals. Although the biological functions of the annexins have not been definitively established, two human diseases involving annexin abnormalities ('annexinopathies') have been identified as of the time of writing. Overexpression of annexin II occurs in the leukocytes of a subset of patients having a hemorrhagic form of acute promyelocytic leukemia. Underexpression of annexin V occurs on placental trophoblasts in the antiphospholipid syndrome and in preeclampsia. Also, an animal model has been described in which annexin VII is underexpressed and is associated with disease, but the relevance of this animal model to human disease is not yet understood. Future research is likely to elucidate additional 'annexinopathies'.

Identification and immunohistochemical localization of annexin II in rat cornea

PURPOSE

We have identified annexin II mRNA expression in the rat cornea and demonstrated immunolocalization of annexin II in normal and injured corneas. Furthermore, to investigate possible interaction between annexin II and its extracellular ligand tenascin during corneal wound healing, we also examined tenascin expression simultaneously.

METHODS

Total RNA was extracted from the corneal tissue of male Wistar rats as well as from the cell cultures of corneal epithelial cells and keratocytes. cDNA was obtained by reverse transcription (RT). Annexin II mRNA expression was examined by polymerase chain reaction (PCR). Western blot analysis of annexin II protein was performed with protein samples that were obtained from the corneal tissue and cell cultures. In addition, the localization of annexin II and that of tenascin were clarified by immunohistochemical analysis, using both uninjured and epithelial scraped corneas.

RESULTS

RT-PCR analysis revealed that annexin II mRNA was expressed in corneal tissues, epithelial cells and keratocytes. Western blot analysis of corneal epithelium and keratocytes showed a 38kDa band that corresponded to the molecular weight of annexin II. Immunohistochemical study showed that annexin II was present in keratocytes as well as the basal cells of corneal epithelium in the central cornea, and basal/suprabasal cells of the limbal epithelium. Positive annexin II immunoreactivity is translocated from cytoplasm to the cell periphery/extracellular position during the epithelial wound healing process. Annexin II and tenascin are coexpressed on the basal surface of limbal epithelium and the leading edge of the healing epithelium. The reappearance of cytoplasmic annexin II staining at the periphery of the cornea correlated with the epithelial cell proliferation.

CONCLUSIONS

Annexin II is abundantly expressed in corneal tissue. The translocalization of annexin II protein suggests its role in the corneal epithelial migration during wound healing. The colocalization of annexin II and tenascin in migrating and proliferating corneal epithelial cells suggests that annexin II-tenascin interaction may play a role in epithelial wound healing.

The Npc1 mutation causes an altered expression of caveolin-1, annexin II and protein kinases and phosphorylation of caveolin-1 and annexin II in murine livers

We have previously demonstrated (1) an increased expression of caveolin-1 in murine heterozygous and homozygous Niemann-Pick type C (NPC) livers, and (2) an increased concentration of unesterified cholesterol in a detergent insoluble caveolae-enriched fraction from homozygous livers. To define further the relationship between caveolin-1 function and the cholesterol trafficking defect in NPC, we examined the expression and distribution of additional caveolar and signal transduction proteins. The expression of annexin II was significantly increased in homozygous liver homogenates and the Triton X-100 insoluble floating fraction (TIFF). Phosphoamino acid analysis of caveolin-1 and annexin II from the homozygous TIFF demonstrated an increase in serine and tyrosine phosphorylation, respectively. To determine the basis for increased phosphorylation of these proteins, the expression and distribution of several protein kinases was examined. The expression of PKCalpha, PKCzeta and pp60-src (protein kinases) were significantly increased in both heterozygous and homozygous liver homogenates, while PKCdelta was increased only in homozygous livers. Of the protein kinases analyzed, only CK IIalpha was significantly enriched in the heterozygous TIFF. Finally, the concentration of diacylglycerol in the homozygous TIFF was significantly increased and this elevation may modulate PKC distribution and function. These results provide additional evidence for involvement of a caveolin-1 containing cellular fraction in the pathophysiology of NPC and also suggest that the Npc1 gene product may directly or indirectly, regulate the expression and distribution of signaling molecules.

Expression of annexin II in glioma cell lines and in brain tumor biopsies

Annexin II is a calcium and phospholipid binding protein and a substrate for protein-tyrosine kinases. Increased levels of annexin II are observed in various cancer cells and tissues, and the molecule has been proposed as a marker of malignancy in vivo. Annexin II was expressed in four glioma cell lines (D-54MG, D-37MG, U251MG and GaMG), as determined by Western blot analyses, immunofluorescence staining and flow cytometric measurements. In addition, annexin II expression was also found in cryostat sections obtained from 15 consecutive brain tumor biopsies: Ten were histologically classified as glioblastomas, one as an astrocytoma, two as meningiomas and two as brain metastases. Cultured spheroids from the glioma cell lines and from three of the glioblastoma biopsies showed lower levels of annexin II, than found in the monolayers of the cell lines and in the freshly cut biopsies. The annexin II expression of the cell lines were not found to be related to their proliferative, migratory or invasive properties. These findings indicate that although annexin II may serve as a marker of malignancy in vivo, its expression can be reduced in vitro, and appear unrelated to malignant features of glioma cell lines.

Expression of Annexin II in Human Middle Ear Cholesteatoma

Annexin II has previously been discovered to have involvements in DNA replication and metabolism, bone resorption, and osteoclast formation. In our work, Western blotting and immunohistostaining studies revealed the presence of annexin II in human cholesteatoma tissue. With monoclonal mouse antiannexin II antibody, a 36,000 dalton protein (annexin II) was identified in the cholesteatoma protein extract. Immunoalkaline-phosphatase staining selectively localized annexin II to the keratinocytes in the basal and spinous layers of the cholesteatoma tissue. In normal human skin, annexin II is expressed mainly in the cytoplasmic membrane of its keratinocytes in the basal layer without significant staining in its nucleus. However, annexin II is expressed in both the cytoplasmic membrane and the nucleus of the keratinocytes in basal and spinous layers of human cholesteatomas. Our findings indicate a possible physiologic role of annexin II in keratinocyte cell hyperproliferation during development of human cholesteatoma.

Expression of annexin II in human middle ear cholesteatoma

Annexin II has previously been discovered to have involvements in DNA replication and metabolism, bone resorption, and osteoclast formation. In our work, Western blotting and immunohistostaining studies revealed the presence of annexin II in human cholesteatoma tissue. With monoclonal mouse antiannexin II antibody, a 36,000 dalton protein (annexin II) was identified in the cholesteatoma protein extract. Immunoalkaline-phosphatase staining selectively localized annexin II to the keratinocytes in the basal and spinous layers of the cholesteatoma tissue. In normal human skin, annexin II is expressed mainly in the cytoplasmic membrane of its keratinocytes in the basal layer without significant staining in its nucleus. However, annexin II is expressed in both the cytoplasmic membrane and the nucleus of the keratinocytes in basal and spinous layers of human cholesteatomas. Our findings indicate a possible physiologic role of annexin II in keratinocyte cell hyperproliferation during development of human cholesteatoma.

The plasminogen activator system in pancreas cancer: role of t-PA in the invasive potential in vitro

Plasminogen activators (PAs) play an important role in tumor cell invasion. We have analysed the expression of tissue-type PA (t-PA), urokinase-type PA (u-PA), and their respective receptors, annexin II and u-PAR, in normal and neoplastic cultures of pancreatic cells, as well as in pancreatic tissues, and have examined their role in tumor invasiveness in vitro. Using Northern blotting, Western blotting, and ELISA, t-PA is detected in cultured pancreas cancer cells displaying a well differentiated phenotype but it is undetectable in less differentiated cells and in normal pancreatic cultures. In contrast, u-PA transcripts, protein, and enzymatic activity are detected both in cancer cells and in normal cultures. Higher levels of u-PAR and annexin II are present in cancer cells than in normal cultures and, in SK-PC-1 cells, both receptors are localized in the basolateral membrane. In vitro invasion assays indicate that both t-PA and u-PA contribute to the invasiveness of SK-PC-1 cells through reconstituted extracellular matrix. To determine the relevance of these studies to pancreas cancer, immunohistochemical assays have been used to examine the expression of t-PA, u-PA, and their receptors in normal and neoplastic tissues. t-PA is absent from normal pancreas and from tumor associated pancreatitis, whereas it is detected in the majority of pancreas cancer tissues (16/17). Annexin II is also overexpressed in some tumors (5/13). u-PAR is overexpressed in most tumor samples examined (14/15), while u-PA is weakly detected in a low number of cases (3/14); both u-PAR and u-PA are overexpressed in areas of tumor associated pancreatitis. Indirect evidences indicate that K-ras and p53 mutated proteins can regulate the expression of PAs. In pancreatic cancer we have found an association between codon 12 K-ras mutations and t-PA expression (P=0.04). These results support the contention that, in the exocrine pancreas, activation of t-PA is more specifically associated to neoplastic transformation and to the invasive phenotype, whereas the induction of u-PA/u-PAR system might be more relevant to inflammatory or non-neoplastic events.

Modification of annexin II expression in PC12 cell lines does not affect Ca(2+)-dependent exocytosis

The Ca2+/phospholipid/cytoskeletal-binding protein annexin II has been proposed to play an important role in Ca(2+)-dependent exocytosis; however, the evidence for this role is inconclusive. More direct evidence obtained by manipulating annexin II levels in cells is still required. We have attempted to do this by generating stably transfected PC12 cell lines expressing proteins which elevate or lower functional annexin II levels and using these cell lines to investigate Ca(2+)-dependent exocytosis. Three cell lines were generated: one expressing an annexin II mutant which aggregates annexin II in at least a proportion of the cells, thereby removing functional protein from the cell; a mixed clonal cell line constitutively overexpressing human annexin II; and a clonal cell line capable of over-expressing annexin II in the presence of sodium butyrate. After digitonin permeabilization, Ca(2+)-dependent dopamine release from these cell lines was compared with that from control nontransfected cells, and, in addition, release was compared in induced to uninduced cells. There were no significant differences in Ca(2+)-dependent exocytosis between any of the transfected cell lines before or after induction and the control cells. In addition, nontransfected PC12 cells treated with nerve growth factor, which elevates annexin II levels severalfold, failed to increase Ca(2+)-dependent exocytosis after digitonin permeabilization, compared with control cells. We conclude that annexin II is not an important regulator of Ca(2+)-dependent exocytosis in PC12 cells.

Overexpression of plasma membrane annexin II in NO2-exposed pulmonary artery endothelial cells

Because exposure to nitrogen dioxide (NO2) alters plasma membrane structure and function in pulmonary artery endothelial cells (PAEC), we examined whether NO2 exposure is associated with upregulation of plasma membrane-specific proteins in PAEC. Exposure to 5 ppm NO2 for 24 h had no significant effect on total protein synthesis. However, two-dimensional gel electrophoresis of isolated plasma membranes from [35S]-methionine pulse-labeled PAEC exposed to NO2 for 24 h demonstrated 3- to 9-fold increases in the synthesis of several proteins with molecular masses of 36, 39, and 40 kDa compared with controls. N-terminal amino acid sequencing and immunodetection analysis identified the 36kDa plasma membrane protein as annexin II (lipocortin II). Northern blotting analysis demonstrated that the mRNA expression for annexin II in NO2-exposed cells was also increased. These results suggest that exposure to NO2 results in induction of plasma membrane annexin II, an important multifunctional calcium- and phospholipid-binding protein in PAEC.

Interferon-alpha-induced human lupus inclusions and p36 protein in cancer and AIDS

Previous work showed that IFN-alpha induced the autoimmune-associated lupus inclusions (LI) in all 16 umbilical cord mononuclear cell samples from healthy mothers. In contrast, IFN-alpha induced LI and the LI-associated protein, p36, in only 2 of 16 human B lymphoblastoid cell lines. Resistance of these 14 cell lines to form LI and p36 may be due to their stage of development or differentiation or their transformed state. We sought to determine whether aging, neoplastic transformation, and HIV infection affected the observed IFN-alpha induction of LI in cord blood mononuclear cells. Expression of LI and p36 was investigated in PBMC on IFN-alpha chemotherapy and on culturing IFN-alpha with PBMC samples prepared from healthy adults and AIDS patients. The IFN-alpha induction of LI (detected by electron microscopy) or p36 (detected by two-dimensional gels) in all of the PBMC samples from these individuals was indistinguishable from the cord blood mononuclear cell response. Furthermore, induction of p36 and LI was not a good indicator of effective IFN-alpha chemotherapy. It may be consequential for autoimmunity induced by IFN-alpha in cancer, AIDS, and systemic lupus erythematosus (SLE). An essential biologic role for p36 and LI is suggested by a highly homologous p36 gene in the invertebrate Caenorhabditis elegans.

Differential expression of annexins I-VI in the rat dorsal root ganglia and spinal cord

The annexins are a family of Ca(2+)-dependent phospholipid-binding proteins. In the present study, the spatial expression patterns of annexins I-VI were evaluated in the rat dorsal root ganglia (DRG) and spinal cord (SC) by using indirect immunofluorescence. Annexin I is expressed in small sensory neurons of the DRG, by most neurons of the SC, and by ependymal cells lining the central canal. Annexin II is expressed by most sensory neurons of the DRG but is primarily expressed in the SC by glial cells. Annexin III is expressed by most sensory neurons, regardless of size, by endothelial cells lining the blood vessels, and by the perineurium. In the SC, annexin III is primarily expressed by astrocytes. In the DRG and the SC, annexin IV is primarily expressed by glial cells and at lower levels by neurons. In the DRG, annexin V is expressed in relatively high concentrations in small sensory neurons in contrast to the SC, where it is expressed mainly by ependymal cells and by small-diameter axons located in the superficial laminae of the dorsal horn areas. Annexin VI is differentially expressed by sensory neurons of the DRG, being more concentrated in small neurons. In the SC, annexin VI has the most striking distribution. It is concentrated subjacent to the plasma membrane of motor neurons and their processes. The differential localization pattern of annexins in cells of the SC and DRG could reflect their individual biological roles in Ca(2+)-signal transduction within the central nervous system.

Purification, microsequencing, and immunolocalization of p36, a new interferon-alpha-induced protein that is associated with human lupus inclusions

The trace interferon-alpha-induced protein, p36, was induced in Raji cells in association with lupus inclusions. It was solubilized in a nonionic detergent buffer, enriched by differential centrifugation and by preparative isoelectric focusing, and purified to homogeneity on two-dimensional protein gels. Failure to obtain N-terminal amino acid sequence, however, suggested a blocked alpha-amino group. Sequences of six tryptic peptides, 13-19 amino acids in length, were obtained after digestion, microbore-high performance liquid chromotography purification, and chemical sequence analysis. None of the six sequences, which represented approximately 25% of the entire protein, shared any meaningful homologies with entries in protein sequence repositories. Raji-cell p36 was shown in Western blots with antipeptide antibodies to be induced at least 400-fold and by immunofluorescence microscopy to co-localize with the endoplasmic reticulum resident protein, protein disulfide isomerase. These results show that p36 is a new interferon-alpha-induced protein that localizes in the endoplasmic reticulum, the cell region in which the lupus inclusions form, and that p36 is probably physically associated with the lupus inclusions.

Overexpression of annexin V in cystic fibrosis epithelial cells from fetal trachea

In this report, we investigated the expression of annexins I, II, V, and VI by Northern and Western blot analysis in four cell lines isolated from human fetal tracheae. Two cell lines were obtained from normal fetuses and the two others from fetuses with cystic fibrosis (CF). One CF fetus was heterozygous for the S549N and N1303K substitutions, whereas the other was homozygous for the delta F508 deletion. We found that the four annexins are always coexpressed. The expression of annexins I, II, and VI was the same in the four cell lines. In contrast, that of annexin V was significantly higher in CF than in normal cells. These observations demonstrate that annexins I, II, V, and VI are independently regulated in tracheal epithelial cell lines. Moreover, they suggest that the overexpressed annexin V, a Ca2+ channel, might profoundly modify Ca2+ transport across the membranes of CF cells.

Modulation of p36 gene expression in human neuronal cells

p36 is a calcium/lipid-binding phosphoprotein that is expressed at high levels in proliferating and transformed cells, and at low levels in terminally differentiated cells, such as CNS neurons. The calcium-dependent binding to membrane phospholipids, and its capacity to interact with intermediate filament proteins suggest that p36 may be involved in the transduction of extracellular signals. The present work examines p36 gene expression in the mature CNS, primary primitive neuroectodermal tumors (PNETs), and transformed PNET cell lines. p36 immunoreactivity was not observed in normal adult human brain, but low levels of the protein were detected by Western blot analysis. Following acute anoxic cerebral injury, the mean levels of p36 protein were elevated two-fold, and injured neurons exhibited increased p36 immunoreactivity. This phenomenon was likely to have been mediated by post-transcriptional mechanisms since there was no corresponding change in the level p36 mRNA. p36 immunoreactivity was detected in 8 of 9 primary PNETs, and in 3 of 3 neurofilament-expressing PNET cell lines. The levels of p36 protein in PNET cell lines were 5-fold higher than in adult human brain tissue. Although p36 gene expression was generally high in proliferating PNET cells, the levels of p36 mRNA and protein were not strictly correlated with DNA synthesis. Instead, p36 gene expression was modulated in both proliferating and non-proliferating PNET cell cultures by treatment with 50 mIU/ml of insulin, 100 mM ethanol, or 5 microM retinoic acid. The frequent discordances observed experimentally and in vivo between p36 mRNA and p36 protein expression suggest that the steady-state levels of p36 protein in neuronal cells may be regulated primarily by post-transcriptional mechanisms.

The expression of phospholipase A2 and lipocortins (annexins) I, II and V in human fetal membranes and placenta in association with labour

We have studied the expression of the cellular, type two phospholipase A2 and lipocortins (annexins) I, II and V in human amnion, chorion-decidua and placenta using northern analysis. We found no difference in the expression of phospholipase A2 or lipocortin V in tissues obtained before or after labour. Lipocortin I expression was found to decrease in amnion and placenta but increase in chorion decidua with the onset of labour, while expression of lipocortin II increased only in amnion. These results support the hypothesis that the increased phospholipase A2 activity in the fetal membranes and placenta which is associated with labour is not due to increased phospholipase A2 gene expression, but that post translational control of phospholipase A2 activity may be mediated through changes in lipocortin I expression.

A major cellular substrate for protein kinases, annexin II, is a DNA-binding protein

We have screened a human cDNA expression library in lambda gt11 for clones encoding Alu-binding proteins using direct binding of labeled Alu DNA to recombinant phage lysates fixed on a membrane, and isolated a clone 98% identical in sequence to the well-known substrate of protein kinases, annexin II, which was suggested earlier to play a role in transduction of mitogenic signals and DNA replication. A diagnostic property of annexins is their binding to phospholipids in the presence of calcium ions, and we have found that the interaction of proteins of human nuclear extracts with Alu subsequences is suppressed by Ca/phosphatidylserine liposomes, suggesting overlapping of Ca/phospholipid- and DNA-binding domains in annexin II.

Cyclic AMP regulation of annexins I, II, V synthesis and localization in cultured porcine thyroid cells

Porcine thyroid cells cultured in the presence of TSH (0.1 mU/ml) or forskolin (10(-5) M) for 4 days display an increased annexin I, II, V biosynthesis when compared with unstimulated cells. Annexin I mostly accumulates in the cytosolic fraction and annexins II and V in the particulate fraction. TSH and forskolin affect in the same manner annexin biosynthesis and localization. In the TSH and forskolin treated cells PGE2 production is very low in comparison with the very high PLA2 activity observed in the dedifferentiated control cells. A strong inhibition of the PGE2 production is observed in control cells incubated with a purified annexin V preparation. These results suggest the existence, in porcine thyroid cells, of a cross-talk between the adenylyl cyclase system and the phospholipase A2 mediated pathways. Annexins' biosynthesis and localization are under the control of the adenylyl cyclase system and participate in this cross-talk.