Cell surface complex of cathepsin B/annexin II tetramer in malignant progression

Preliminary Correlation of the Immunoexpression of Cathepsin B and E-Cadherin Proteins in Vocal Fold Leukoplakia

OBJECTIVES

Early identification of vocal fold leukoplakia (VFL), which has a risk of progressing to malignant transformation, remains a controversial topic. The identification of biological markers for diagnosing these lesions would lead to a more effective treatment. We aimed to analyze the immunoexpression of cathepsin B and E-cadherin in VFL and correlate it with clinical and epidemiological data and disease prognosis.

METHODS

Thirty-two patients with VFL treated with microsurgery were retrospectively evaluated. The patients were distributed according to the histological results into Group A (low grade) and Group B (high grade). The expression of markers was quantitatively determined as per their staining intensity and tissue distribution using ImageLab. The index of expression (IE) of each marker was correlated with tobacco and alcohol consumption, signs of laryngopharyngeal reflux, and local recurrence of the lesion.

RESULTS

The correlation between the IE of markers and variables within the two groups (A and B) demonstrated that patients in Group B with local recurrence had a higher IE of cathepsin B. When all patients (A + B) were included, the same analysis demonstrated that the IE of cathepsin B was higher among smokers and patients who did not show signs of reflux and that the IE of E-cadherin was higher only in patients with recurrence.

CONCLUSION

Patients with moderate to severe dysplasia and carcinoma in situ who smoked as well as had a high IE of cathepsin B were more prone to local recurrence. Regardless of the type of histological lesion, patients with signs of laryngopharyngeal reflux had a lower IE of cathepsin B. The IE of E-cadherin was higher among patients with VFL who relapsed after initial treatment.

Molecular Engineering of Sulfone-Xanthone Chromophore for Enhanced Fluorescence Navigation

Enriching the palette of high-performance fluorescent dyes is vital to support the frontier of biomedical imaging. Although various rhodamine skeletons remain the premier type of small-molecule fluorophores due to the apparent high brightness and flexible modifiability, they still suffer from the inherent defect of small Stokes shift due to the nonideal fluorescence imaging signal-to-background ratio. Especially, the rising class of fluorescent dyes, sulfone-substituted xanthone, exhibits great potential, but low chemical stability is also pointed out as the problem. Molecular engineering of sulfone-xanthone to obtain a large Stokes shift and high stability is highly desired, but it is still scarce. Herein, we present the combination modification method for optimizing the performance of sulfone-xanthone. These redesigned fluorescent skeletons owned greatly improved stability and Stokes shift compared with the parent sulfone-rhodamine. To the proof of bioimaging capacity, annexin protein-targeted peptide LS301 was introduced to the most promising dyes, J-S-ARh, to form the tumor-targeted fluorescent probe, J-S-LS301. The resulting probe, J-S-LS301, can be an outstanding fluorescence tool for the orthotopic transplantation tumor model of hepatocellular carcinoma imaging and on-site pathological analysis. In summary, the combination method could serve as a basis for rational optimization of sulfone-xanthone. Overall, the chemistry reported here broadens the scope of accessible sulfone-xanthone functionality and, in turn, enables to facilitate the translation of biomedical research toward the clinical domain.

Recent Advances in Molecular and Cellular Functions of S100A10

S100A10 (p11, annexin II light chain, calpactin light chain) is a multifunctional protein with a wide range of physiological activity. S100A10 is unique among the S100 family members of proteins since it does not bind to Ca2+, despite its sequence and structural similarity. This review focuses on studies highlighting the structure, regulation, and binding partners of S100A10. The binding partners of S100A10 were collated and summarized.

Galectin-3 promotes secretion of proteases that decrease epithelium integrity in human colon cancer cells

Galectin-3 is a galactoside-binding protein that is commonly overexpressed in many epithelial cancers. It is increasingly recognized as a multi-functional, multi-mode promoter in cancer development, progression, and metastasis. This study reports that galectin-3 secretion by human colon cancer cells induces cancer cell secretion, in an autocrine/paracrine manner, of a number of proteases including cathepsin-B, MMP-1 and MMP-13. The secretion of these proteases causes disruption of epithelial monolayer integrity, increases its permeability and promotes tumour cell invasion. This effect of galectin-3 is shown to be mediated through induction of cellular PYK2-GSK3α/β signalling and can be prevented by the presence of galectin-3 binding inhibitors. This study thus reveals an important mechanism in galectin-3-mediated promotion of cancer progression and metastasis. It provides further evidence to the increased realization of galectin-3 as a potential therapeutic target for the treatment of cancer.

Dipeptide-Derived Alkynes as Potent and Selective Irreversible Inhibitors of Cysteine Cathepsins

The potential of designing irreversible alkyne-based inhibitors of cysteine cathepsins by isoelectronic replacement in reversibly acting potent peptide nitriles was explored. The synthesis of the dipeptide alkynes was developed with special emphasis on stereochemically homogeneous products obtained in the Gilbert-Seyferth homologation for C≡C bond formation. Twenty-three dipeptide alkynes and 12 analogous nitriles were synthesized and investigated for their inhibition of cathepsins B, L, S, and K. Numerous combinations of residues at positions P1 and P2 as well as terminal acyl groups allowed for the derivation of extensive structure-activity relationships, which were rationalized by computational covalent docking for selected examples. The determined inactivation constants of the alkynes at the target enzymes span a range of >3 orders of magnitude (3-10 133 M^-1 s^-1). Notably, the selectivity profiles of alkynes do not necessarily reflect those of the nitriles. Inhibitory activity at the cellular level was demonstrated for selected compounds.

The cooperative folding of annexin A2 relies on a transient nonnative intermediate

Annexins (Anxs) are a family of highly homologous proteins that bind and aggregate lipid vesicles in the presence of calcium. All members of the family contain a variable N-terminus determining specific functions, followed by a conserved core region responsible for the general calcium-dependent lipid-binding property. The core structure consists of four homologous domains (DI-DIV), each consisting of a right-handed super-helix of five α-helices. We present data from a combination of site-directed mutagenesis, NMR, and circular dichroism showing that the G25-D34 region of the N-terminus as well as the contacts between residues D38A, R63A, and Q67A of AnxA2-DI are crucial for the autonomous folding and stability of DI of AnxA2. However, we also show that the folding of the full-length protein is very robust in that mutations and truncations that disrupted the folding of AnxA2-DI did not abolish the folding of full-length AnxA2, only lowering its thermal stability. This robustness of the folding of full-length AnxA2 is likely to be mediated by the existence of at least one transient nonnative intermediate as suggested by our kinetic data using stopped-flow fluorescence experiments. We also show that hydrophobic amino acids in AnxA2-DI involved in interfacial contacts with AnxA2-DIV are important for the cooperative folding and stability of the full-length protein. Mutating all of the V57E-V98R-G101Y residues in AnxA2-DI did not affect the folding of the domain, only its stability, but prevented the cooperative folding of the full-length protein. Our collective results favor a highly cooperative and robust folding process mediated by alternative intermediate steps. Since AnxA2 is a multifunctional protein involved in several steps of the progression of cell transformation, these data on structure and folding pathways are therefore crucial to designing anticancer drugs targeting AnxA2.

Uncloaking cell-impermeant gold nanorods via tumor microenvironmental cathepsin B facilitates cancer cell penetration and potent radiosensitization

Major impediments to conveyance of intravenously administered drugs to tumors are biofouling, opsonization, and rapid clearance from the circulation by macrophages and reticuloendothelial phagocytes. Cloaking nanoparticles with stealth epilayers partly overcomes these hurdles but it also foils interactions with tumor cells. Here, we describe the synthesis, characterization, and validation of smart gold nanorods (GNRs) that spontaneously transform from inert passengers in the blood stream to active cell-penetrating nanoparticles within tumors to potently sensitize tumors to radiation therapy. Intrinsically cationic and cell-penetrating GNRs were shielded from phagocytosis with a cloaking polyethylene glycol epilayer containing an intervening cleavable peptide. In the absence of an external trigger, this epilayer is clipped off by the tumor microenvironmental protease, cathepsin B, in colorectal cancers to uncloak and expose the free-circulating native unPEGylated GNR that is readily internalized by cancer cells and turn into immovable small clusters of GNRs. Selective uncloaking of GNRs in the tumor reduced off-target toxicity confirmed by hematologic, biochemical, and histopathological analysis of blood, serum, and normal organs, respectively. Subsequent irradiation led to significant tumor growth delay and improved survival of mice. By addressing multiple barriers to efficient transport and cellular internalization of nanoparticles, our results demonstrate that clinically meaningful radiosensitization can be achieved with rationally designed GNRs.

Encephalomyocarditis Virus 2A Protein Inhibited Apoptosis by Interaction with Annexin A2 through JNK/c-Jun Pathway

Encephalomyocarditis virus can cause myocarditis and encephalitis in pigs and other mammals, thus posing a potential threat to public health safety. The 2A protein is an important virulence factor of EMCV. Previous studies have shown that the 2A protein may be related to the inhibition of apoptosis by virus, but its specific molecular mechanism is not clear. In this study, the 2A protein was expressed in Escherichia coli in order to find interacting cell proteins. A pull down assay, coupled with mass spectrometry, revealed that the 2A protein possibly interacted with annexin A2. Co-immunoprecipitation assays and confocal imaging analysis further demonstrated that the 2A protein interacted with annexin A2 in cells. In reducing the expression of annexin A2 by siRNA, the ability of the 2A protein to inhibit apoptosis was weakened and the proliferation of EMCV was slowed down. These results suggest that annexin A2 is closely related to the inhibition of apoptosis by 2A. Furthermore, both RT-PCR and western blot results showed that the 2A protein requires annexin A2 interaction to inhibit apoptosis via JNK/c-Jun pathway. Taken together, our data indicate that the 2A protein inhibits apoptosis by interacting with annexin A2 via the JNK/c-Jun pathway. These findings provide insight into the molecular pathogenesis underlying EMCV infection.

Molecular dynamic simulation (MDS) and in vitro cathepsin-B inhibitory activity of decrusin angelate, ibuprofen, and thymol

Attenuation of cathepsin B (CATB) proteolytic activity and/or inhibition serves as a potential therapeutic target in cancer metastasis. Herein, we determined the specificity of FDA approved potential anti-cancer natural flavonoid decursinol angelate (DA), thymol (TH) and a propionic acid derivative ibuprofen (IB), for the inactivation of CATB. We used enzymatic assay, computational and in vitro methods for the identification of the best candidate. Out of these we found DA can inhibit CATB with lowest IC₅₀ measured after one hour of incubation using Z-Phe-Arg-4MβNA (BANA) as a substrate. Docking analysis suggested favorable interaction of DA with the catalytic site residues (GLN23, CYS26, HIS110, HIS111) of CATB (PDB Id: 1HUC) were responsible for the inhibition of its proteolytic activity. Additionally, in vitro quantification with human colorectal carcinoma (HCT 116) revealed, DA rapidly inactivates CATB as compared with commercial synthetic inhibitor CA074 with no cellular toxicity towards normal colon cells (CCD 841).

Plasmin and Plasminogen System in the Tumor Microenvironment: Implications for Cancer Diagnosis, Prognosis, and Therapy

Simple Summary

In this review, we present a detailed discussion of how the plasminogen-activation system is utilized by tumor cells in their unrelenting attack on the tissues surrounding them. Plasmin is an enzyme which is responsible for digesting several proteins that hold the tissues surrounding solid tumors together. In this process tumor cells utilize the activity of plasmin to digest tissue barriers in order to leave the tumour site and spread to other parts of the body. We specifically focus on the role of plasminogen receptor—p11 which is an important regulatory protein that facilitates the conversion of plasminogen to plasmin and by this means promotes the attack by the tumour cells on their surrounding tissues.

Abstract

The tumor microenvironment (TME) is now being widely accepted as the key contributor to a range of processes involved in cancer progression from tumor growth to metastasis and chemoresistance. The extracellular matrix (ECM) and the proteases that mediate the remodeling of the ECM form an integral part of the TME. Plasmin is a broad-spectrum, highly potent, serine protease whose activation from its precursor plasminogen is tightly regulated by the activators (uPA, uPAR, and tPA), the inhibitors (PAI-1, PAI-2), and plasminogen receptors. Collectively, this system is called the plasminogen activation system. The expression of the components of the plasminogen activation system by malignant cells and the surrounding stromal cells modulates the TME resulting in sustained cancer progression signals. In this review, we provide a detailed discussion of the roles of plasminogen activation system in tumor growth, invasion, metastasis, and chemoresistance with specific emphasis on their role in the TME. We particularly review the recent highlights of the plasminogen receptor S100A10 (p11), which is a pivotal component of the plasminogen activation system.

Taxon-Specific Proteins of the Pathogenic Entamoeba Species E. histolytica and E. nuttalli

The human protozoan parasite Entamoeba histolytica can live in the human intestine for months or years without generating any symptoms in the host. For unknown reasons, amoebae can suddenly destroy the intestinal mucosa and become invasive. This can lead to amoebic colitis or extraintestinal amoebiasis whereby the amoebae spread to other organs via the blood vessels, most commonly the liver where abscesses develop. Entamoeba nuttalli is the closest genetic relative of E. histolytica and is found in wild macaques. Another close relative is E. dispar, which asyptomatically infects the human intestine. Although all three species are closely related, only E. histolytica and E. nuttalli are able to penetrate their host’s intestinal epithelium. Lineage-specific genes and gene families may hold the key to understanding differences in virulence among species. Here we discuss those genes found in E. histolytica that have relatives in only one or neither of its sister species, with particular focus on the peptidase, AIG, Ariel, and BspA families.

Diagnostic Value of Plasma Annexin A2 in Early-Stage High-Grade Serous Ovarian Cancer

Ovarian cancer (OC) is commonly diagnosed at advanced stage when prognosis is poor. Consequently, there is an urgent clinical need to identify novel biomarkers for early detection to improve survival. We examined the diagnostic value of the calcium phospholipid binding protein annexin A2 (ANXA2), which plays an important role in OC metastasis. Annexin A2 plasma levels in patients with high grade serous OC (n = 105), benign ovarian lesions (n = 55) and healthy controls (n = 143) were measured by ELISA. Annexin A2 levels were found to be significantly increased in patients with stage I (p < 0.0001) and stage IA (p = 0.0027) OC when compared to healthy controls. In the logistic regression models followed by receiver operating characteristics (ROC) curve analyses, plasma annexin A2 showed 46.7% sensitivity at 99.6% specificity in distinguishing stage IA OC patients from healthy controls and 75% sensitivity at 65.5% specificity in the diagnosis of stage IA versus benign ovarian tumors. In the diagnosis of stage IA OC versus normal controls, the combination of plasma annexin A2 and CA125 showed 80% sensitivity at 99.6% specificity (AUC = 0.970) which was significantly higher than for CA125 (53.3% sensitivity at 99.6% specificity; AUC = 0.891) alone. The diagnostic accuracy in distinguishing stage IA OC from benign ovarian disease when combining annexin A2 and CA125 (71.4% accuracy at 100% sensitivity) was almost twice as high compared to CA125 (37.1% accuracy at 100% sensitivity) alone. In conclusion, annexin A2 in combination with CA125 has potential as a biomarker for the early detection of OC and to predict malignancy in patients with ovarian lesions, warranting further investigations.

Membranous S100A10 involvement in the tumor budding of colorectal cancer during oncogenesis: report of two cases with immunohistochemical analysis

Background

Tumor budding (TB) and poorly differentiated clusters (PDCs) are a sequence of histologic findings that predict worse prognosis and node metastasis in colorectal cancer (CRC). TB and PDC (TB/PDC) are caused by cancer cell detachment and are distinguished by the number of cancer cells that constitute a cell cluster. In short, PDC is regarded as the previous step of TB. TB/PDC and epithelial-mesenchymal transition (EMT) are closely linked, but its pathogenic mechanisms are still unclear. S100A10, a member of the S100 protein family, forms a heterocomplex with annexin A2 (ANX A2) and then translocates to cell membrane from the cytoplasm and plays various roles in cell dynamics, including plasminogen activation. S100A10 is the activation modulator of the heterocomplex and promotes cell invasion. S100A10 is involved in the remodeling of both actin and extracellular matrix (ECM), which is also associated with EMT.

Case presentation

In two representative cases of conventional advanced CRC, we immunohistochemically examined S100A10 and ANX A2 expressions in which both TB and PDC were prominent. Both CRCs metastasized to multiple regional lymph nodes. In both cases, a membranous positivity for S100A10 was diffusely found in both tumor buds and PDCs and was observed in the tumor cells protruding toward the stroma, giving rise to TB/PDC. However, even in tumor glands with TB/PDC, the tumor cells with a smooth border around the stroma showed either cytoplasmic fine-granular expression or no positivity. The immunoreactivity for ANX A2 was almost the same as that for S100A10. In the main tumor components without TB/PDC, no distinct positivity was detected at their smooth borders.

Conclusions

During oncogenesis, membranous S100A10 has the potential to be related to TB of CRC. This may be due to plasminogen activation, actin remodeling, and interaction with an altered ECM. However, further study is required to confirm this hypothesis.

Selective imaging of solid tumours via the calcium-dependent high-affinity binding of a cyclic octapeptide to phosphorylated Annexin A2

The heterogeneity and continuous genetic adaptation of tumours complicate their detection and treatment via the targeting of genetic mutations. However, hallmarks of cancer such as aberrant protein phosphorylation and calcium-mediated cell signalling provide broadly conserved molecular targets. Here, we show that, for a range of solid tumours, a cyclic octapeptide labelled with a near-infrared dye selectively binds to phosphorylated Annexin A2 (pANXA2), with high affinity at high levels of calcium. Because of cancer-cell-induced pANXA2 expression in tumour-associated stromal cells, the octapeptide preferentially binds to the invasive edges of tumours, and then traffics within macrophages to the tumour’s necrotic core. As proof-of-concept applications, we used the octapeptide to detect tumour xenografts and metastatic lesions, and to perform fluorescence-guided surgical tumour resection, in mice. Our findings suggest that high levels of pANXA2 in association with elevated calcium are present in the microenvironment of most solid cancers. The octapeptide might be broadly useful for selective tumour imaging and for delivering drugs to the edges and to the core of solid tumours.

Hedgehog signaling stimulates Tenascin C to promote invasion of pancreatic ductal adenocarcinoma cells through Annexin A2

Pancreatic adenocarcinoma (PDA) is characterized by a dense desmoplastic reaction that comprises 60-90% of the tumor, while only 10-40% of the tumor is composed of malignant epithelial cells. This desmoplastic reaction is composed of stromal fibroblast cells, extracellular matrix proteins, and immune cells. Accumulating evidence has suggested that the stromal and epithelial cell compartments interact during the pathogenesis of this disease. Therefore, it is important to identify the signaling pathways responsible for this interaction to better understand the mechanisms by which PDA invades and metastasizes. Here, we show that secreted stromal factors induce invasion of PDA cells. Specifically, hedgehog signaling from the tumor cells induces tenascin C (TnC) secretion from the stromal cells that acts back upon the tumor cells in a paracrine fashion to induce the invasion of PDA cells through its' receptor annexin A2 (AnxA2). Therefore, blocking the interaction between TnC and AnxA2 has the potential to prevent liver metastasis in PDA.

FXYD5 (dysadherin) may mediate metastatic progression through regulation of the β-Na+-K+-ATPase subunit in the 4T1 mouse breast cancer model

FXYD5 is a Na+-K+-ATPase regulator, expressed in a variety of normal epithelia. In parallel, it has been found to be associated with several types of cancer and effect lethal outcome by promoting metastasis. However, the molecular mechanism underlying FXYD5 mediated invasion has not yet been identified. In this study, using in vivo 4T1 murine breast cancer model, we found that FXYD5-specific shRNA significantly inhibited lung cancer metastasis, without having a substantial effect on primary tumor growth. Our study reveals that FXYD5 participates in multiple stages of metastatic development and exhibits more than one mode of E-cadherin regulation. We provide the first evidence that FXYD5-related morphological changes are mediated through its interaction with Na+-K+-ATPase. Experiments in cultured 4T1 cells have indicated that FXYD5 expression may downregulate the β1 isoform of the pump. This behavior could have implications on both transcellular interactions and intracellular events. Further studies suggest that differential localization of the adaptor protein Annexin A2 in FXYD5-expressing cells may correlate with matrix metalloproteinase 9 secretion and adhesion changes in 4T1 wild-type cells.

WOMEN IN CANCER THEMATIC REVIEW: Ovarian cancer-peritoneal cell interactions promote extracellular matrix processing

Ovarian cancer has a distinct tendency for metastasising via shedding of cancerous cells into the peritoneal cavity and implanting onto the peritoneum that lines the pelvic organs. Once ovarian cancer cells adhere to the peritoneal cells, they migrate through the peritoneal layer and invade the local organs. Alterations in the extracellular environment are critical for tumour initiation, progression and intra-peritoneal dissemination. To increase our understanding of the molecular mechanisms involved in ovarian cancer metastasis and to identify novel therapeutic targets, we recently studied the interaction of ovarian cancer and peritoneal cells using a proteomic approach. We identified several extracellular matrix (ECM) proteins including, fibronectin, TGFBI, periostin, annexin A2 and PAI-1 that were processed as a result of the ovarian cancer-peritoneal cell interaction. This review focuses on the functional role of these proteins in ovarian cancer metastasis. Our findings together with published literature support the notion that ECM processing via the plasminogen-plasmin pathway promotes the colonisation and attachment of ovarian cancer cells to the peritoneum and actively contributes to the early steps of ovarian cancer metastasis.

Prognostic significance of annexin A2 and annexin A4 expression in patients with cervical cancer

BACKGROUND

The annexins (ANXs) have diverse roles in tumor development and progression, however, their clinical significance in cervical cancer has not been elucidated. The present study was to investigate the clinical significance of annexin A2 (ANXA2) and annexin A4 (ANXA4) expression in cervical cancer.

METHODS

ANXA2 and ANXA4 immunohistochemical staining were performed on a cervical cancer tissue microarray consisting of 46 normal cervical epithelium samples and 336 cervical cancer cases and compared the data with clinicopathological variables, including the survival of cervical cancer patients.

RESULTS

ANXA2 expression was lower in cancer tissue (p = 0.002), whereas ANXA4 staining increased significantly in cancer tissues (p < 0.001). ANXA2 expression was more prominent in squamous cell carcinoma (p < 0.001), whereas ANXA4 was more highly expressed in adeno/adenosquamous carcinoma (p < 0.001). ANXA2 overexpression was positively correlated with advanced cancer phenotypes, whereas ANXA4 expression was associated with resistance to radiation with or without chemotherapy (p = 0.029). Notably, high ANXA2 and ANXA4 expression was significantly associated with shorter disease-free survival (p = 0.004 and p = 0.033, respectively). Multivariate analysis indicated that ANXA2+ (HR = 2.72, p = 0.003) and ANXA2+/ANXA4+ (HR = 2.69, p = 0.039) are independent prognostic factors of disease-free survival in cervical cancer. Furthermore, a random survival forest model using combined ANXA2, ANXA4, and clinical variables resulted in improved predictive power (mean C-index, 0.76) compared to that of clinical-variable-only models (mean C-index, 0.70) (p = 0.006).

CONCLUSIONS

These findings indicate that detecting ANXA2 and ANXA4 expression may aid the evaluation of cervical carcinoma prognosis.

Proteins from formalin-fixed paraffin-embedded prostate cancer sections that predict the risk of metastatic disease

Background

Prostate cancer is the most frequently diagnosed cancer in men and the third leading cause of cancer related deaths among men living in developed countries. Biomarkers that predict disease outcome at the time of initial diagnosis would substantially aid disease management.

Results

Proteins extracted from formalin-fixed paraffin-embedded tissue were identified using nanoflow liquid chromatography-MALDI MS/MS or after separation by one- or two-dimensional electrophoresis. The proteomics data have been deposited to the ProteomeXchange with identifier PXD000963. A list of potential biomarker candidates, based on proposed associations with prostate cancer, was derived from the 320 identified proteins. Candidate biomarkers were then examined by multiplexed Western blotting of archival specimens from men with premetastatic disease and subsequent disease outcome data. Annexin A2 provided the best prediction of risk of metastatic disease (log-rank Chi squared p = 0. 025). A tumor/control tissue >2-fold relative abundance increase predicted early biochemical failure, while <2-fold change predicted late or no biochemical failure.

Conclusions

This study confirms the potential for use of archival FFPE specimens in the search for prognostic biomarkers for prostate cancer and suggests that annexin A2 abundance in diagnostic biopsies is predictive for metastatic potential. Protein profiling each cancer may lead to an overall reduction in mortality from metastatic prostate cancer as well as reduced treatment associated morbidity.

Electronic supplementary material

The online version of this article (doi:10.1186/s12014-015-9096-3) contains supplementary material, which is available to authorized users.

Expression and significance of annexin A2 in patients with gastric adenocarcinoma and the association with E-cadherin

Annexin A2 is a calcium-dependent phospholipid-binding protein, involved in invasion, angiogenesis and migration in cancer cells. The aims of the present study were to evaluate the expression levels of annexin A2 and E-cadherin in gastric adenocarcinoma (GAC), and to investigate the association between the expression of annexin A2 and that of E-cadherin and Ki67, in addition to various clinicopathological factors. This study included 126 patients that were histopathologically diagnosed with GAC. Tissue samples were acquired by surgical resection, and annexin A2 mRNA expression levels were determined using reverse transcription-quantitative polymerase chain reaction. Annexin A2, E-cadherin and Ki67 protein expression levels were detected using western blot analysis and/or immunohistochemical staining. The expression of annexin A2 mRNA and protein was significantly upregulated in the GAC tissues. Annexin A2 expression was detected in 52/126 cases (41.3%) of gastric cancer (GC), and correlations were identified between annexin A2 expression and Tumor, Node, Metastasis (TNM) stage (P=0.002), lymph node metastasis (P=0.016) and distal metastasis (P=0.005). The positive expression rates of E-cadherin and Ki67 in the tumor tissue of patients with GAC were 27.8% (35/126) and 56.2% (71/126), respectively. A negative correlation was observed between the expression of annexin A2 and E-cadherin (P<0.001). No significant association was detected between the expression levels of annexin A2 and Ki67 (P=0.801). In conclusion, upregulated annexin A2 expression was associated with lymph node metastasis, distal metastasis, advanced TNM stage and E-cadherin expression in patients with GAC. The association between the expression of annexin A2 and that of E-cadherin may indicate an underlying mechanism by which annexin A2 contributes to the metastasis in GC, and thus annexin A2 may represent a potential target for the treatment of GAC.

Association of annexin A2 with cancer development (Review)

Annexin A2 (ANXA2) is a well-known calcium-dependent phospholipid binding protein widely distributed in the nucleus, cytoplasm and extracellular surface of various eukaryotic cells. It has been recognized as a pleiotropic protein affecting a wide range of molecular and cellular processes. Dysregulation and abnormal expression of ANXA2 are linked to a large number of prevalent diseases, including autoimmune and neurodegenerative disease, antiphospholipid syndrome, inflammation, diabetes mellitus and a series of cancers. Accumulating data suggest that ANXA2 is aberrantly expressed in a wide spectrum of cancers, and exerts profound effects on tumor cell adhesion, proliferation, apoptosis, invasion and metastasis as well as tumor neovascularization via different modes of action. However, despite significant research, our knowledge of the mechanism by which ANXA2 participates in cancer development remains fragmented. The present review systematically summarizes the effects of ANXA2 on tumor progression, in an attempt to gain an improved understanding of the underlying mechanisms and to provide a potential effective target for cancer therapy.

Genetic Instability and Disease Prognostication

Genetic instability is a striking feature of human cancers, with an impact on the genesis, progression and prognosis. The clinical importance of genomic instability and aneuploidy is underscored by its association with poor patient outcome in multiple cancer types, including breast and colon cancer. Interestingly, there is growing evidence that prognostic gene expression signatures simply reflect the degree of genomic instability. Additionally, also the proteome is affected by aneuploidy and has therefore become a powerful tool to screen for new targets for therapy, diagnosis and prognostication. In this context, the chapter presents the impact of genomic instability on disease prognostication occurring in human cancers.

Circulating annexin A2 as a biomarker in gastric cancer patients: correlation with clinical variables

Annexin A2 (ANXA2) plays an important role in the pathogenesis of multiple malignancies and its expression strongly also affects the outcomes of cancer patients. The objective of this study was to determine the clinical significance of the serum levels of ANXA2 in patients with gastric cancer. A total of 63 patients with a pathologically confirmed diagnosis of gastric cancer were enrolled into this study. Serum ANXA2 concentrations were determined by the solid-phase sandwich ELISA method. Age- and sex-matched 30 healthy controls were included in the analysis. The median age at diagnosis was 62years, range 28 to 82years. The baseline serum ANXA2 levels of the gastric cancer patients were a significantly higher than those in the control group (P<0.001). The known clinical variables including age of patient, gender, site of lesion, histology, histological grade, stage of disease, and serum levels of LDH, carcinoembryonic antigen (CEA), and carbohydrate antigen (CA) 19.9 were not found to be correlated with serum ANXA2 concentrations (P>0.05). However, the chemotherapy-unresponsive patients had higher serum ANXA2 levels compared with chemotherapy-responsive ones (P=0.04). Conversely, serum ANXA2 concentration was found no prognostic role on survival (P=0.53). In conclusion, serum levels of ANXA2 may have a good diagnostic and predictive marker for response to chemotherapy in patients with gastric cancer and have not associated with prognosis.

Tissue-type plasminogen activator deficiency delays bone repair: roles of osteoblastic proliferation and vascular endothelial growth factor

Further development in research of bone regeneration is necessary to meet the clinical demand for bone reconstruction. Recently, we reported that plasminogen is crucial for bone repair through enhancement of vessel formation. However, the details of the role of tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA) in the bone repair process still remain unknown. Herein, we examined the effects of plasminogen activators on bone repair after a femoral bone defect using tPA-deficient (tPA(-/-)) and uPA-deficient (uPA(-/-)) mice. Bone repair of the femur was delayed in tPA(-/-) mice, unlike that in wild-type (tPA(+/+)) mice. Conversely, the bone repair was comparable between wild-type (uPA(+/+)) and uPA(-/-) mice. The number of proliferative osteoblasts was decreased at the site of bone damage in tPA(-/-) mice. Moreover, the proliferation of primary calvarial osteoblasts was reduced in tPA(-/-) mice. Recombinant tPA facilitated the proliferation of mouse osteoblastic MC3T3-E1 cells. The proliferation enhanced by tPA was antagonized by the inhibition of endogenous annexin 2 by siRNA and by the inhibition of extracellular signal-regulated kinase (ERK)1/2 phosphorylation in MC3T3-E1 cells. Vessel formation as well as the levels of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-1α (HIF-1α) were decreased at the damaged site in tPA(-/-) mice. Our results provide novel evidence that tPA is crucial for bone repair through the facilitation of osteoblast proliferation related to annexin 2 and ERK1/2 as well as enhancement of vessel formation related to VEGF and HIF-1α at the site of bone damage.

A ray of venom: Combined proteomic and transcriptomic investigation of fish venom composition using barb tissue from the blue-spotted stingray (Neotrygon kuhlii)

Fish venoms remain almost completely unstudied despite the large number of species. In part this is due to the inherent nature of fish venoms, in that they are highly sensitive to heat, pH, lyophilisation, storage and repeated freeze-thawing. They are also heavily contaminated with mucus, which makes proteomic study difficult. Here we describe a novel protein-handling protocol to remove mucus contamination, utilising ammonium sulphate and acetone precipitation. We validated this approach using barb venom gland tissue protein extract from the blue-spotted stingray Neotrygon kuhlii. We analysed the protein extract using 1D and 2D gels with LC-MS/MS sequencing. Protein annotation was underpinned by a venom gland transcriptome. The composition of our N. kuhlii venom sample revealed a variety of protein types that are completely novel to animal venom systems. Notably, none of the detected proteins exhibited similarity to the few toxin components previously characterised from fish venoms, including those found in other stingrays. Putative venom toxins identified here included cystatin, peroxiredoxin and galectin. Our study represents the first combined survey of gene and protein composition from the venom apparatus of any fish and our novel protein handling method will aid the future characterisation of toxins from other unstudied venomous fish lineages.

BIOLOGICAL SIGNIFICANCE

These results show an efficient manner for removing mucus from fish venoms. These results are the first insights into the evolution of proteins present on stingrayvenom barbs.

Annexin A2 is regulated by ovarian cancer-peritoneal cell interactions and promotes metastasis

Our recent research identified the protein annexin A2 to be regulated by ovarian cancer-peritoneal cell interactions. This study investigated the role of annexin A2 in ovarian cancer metastasis and its potential utility as a novel therapeutic target, using in vitro and in vivo ovarian cancer models. Annexin A2 expression was examined by qRT-PCR and western blotting in ovarian cancer cell lines and immunohistochemistry in serous ovarian carcinoma tissues. Annexin A2 siRNAs were used to evaluate the effects of annexin A2 suppression on ovarian cancer cell adhesion, motility, and invasion. Furthermore, annexin A2 neutralizing antibodies were used to examine the role of annexin A2 in tumor invasion and metastasis in vivo using a chick chorioallantoic membrane assay and an intraperitoneal xenograft mouse model. Strong annexin A2 immunostaining was observed in 90% (38/42) of the serous ovarian cancer cells and was significantly increased in the cancer-associated stroma compared to non-malignant ovarian tissues. Annexin A2 siRNA significantly inhibited the motility and invasion of serous ovarian cancer cells and adhesion to the peritoneal cells. Annexin A2 neutralizing antibodies significantly inhibited OV-90 cell motility and invasion in vitro and in vivo using the chick chorioallantoic membrane assay. The growth of SKOV-3 cells and their peritoneal dissemination in nude mice was significantly inhibited by annexin A2 neutralizing antibodies. Annexin A2 plays a critical role in ovarian cancer metastasis and is therefore a potential novel therapeutic target against ovarian cancer.

Dynamic reciprocity: the role of annexin A2 in tissue integrity

Interactions between cells and the extracellular matrix are integral to tissue development, remodelling and pathogenesis. This is underlined by bi-directional flow of information signalling, referred to as dynamic reciprocity. Annexin A2 is a complex and multifunctional protein that belongs to a large family of Ca(2+)-dependent anionic phospholipid and membrane-binding proteins. It has been implicated in diverse cellular processes at the nuclear, cytoplasmic and extracellular compartments including Ca(2+)-dependent regulation of endocytosis and exocytosis, focal adhesion dynamics, transcription and translation, cell proliferation, oxidative stress and apoptosis. Most of these functions are mediated by the annexin A2-S100A10 heterotetramer (AIIt) via its ability to simultaneously interact with cytoskeletal, membrane and extracellular matrix components, thereby mediating regulatory effects of extracellular matrix adhesion on cell behaviour and vice versa. While Src kinase-mediated phosphorylation of filamentous actin-bound AIIt results in membrane-cytoskeletal remodelling events which control cell polarity, cell morphology and cell migration, AIIt at the cell surface can bind to a number of extracellular matrix proteins and catalyse the activation of serine and cysteine proteases which are important in facilitating tissue remodelling during tissue repair, neoangiogenesis and pathological situations. This review will focus on the role of annexin A2 in regulating tissue integrity through intercellular and cell-extracellular matrix interaction. Annexin A2 is differentially expressed in various tissue types as well as in many pathologies, particularly in several types of cancer. These together suggest that annexin A2 acts as a central player during dynamic reciprocity in tissue homeostasis.

Characterization of the shear stress regulation of CD18 surface expression by HL60-derived neutrophil-like cells

Shear stress-induced cleavage of cell surface CD18 integrins is reported to be part of an anti-inflammatory control mechanism that minimizes neutrophil activity in the blood under physiologic conditions. The cysteine protease, cathepsin B (catB), has been implicated in this mechanoregulatory mechanism, but its molecular dynamics remain to be elucidated. Moreover, attempts to do so using molecular approaches are hindered by the limited ex vivo life span of primary neutrophils. As an alternative, we explored the potential use of HL60-derived neutrophilic cells as a transfectable culture model that exhibits a shear-induced CD18 cleavage response comparable to primary neutrophils. HL60 cells were differentiated into neutrophil-like cells (dHL60-NCs) and exposed to laminar shear stress ([Formula: see text] for 10 min). Based on cytometric analyses, sheared cells cleaved CD18 and CD11a, but not CD11b, integrins. Treatment of cells with E64 or doxycycline prior to and during shear exposure inhibited CD18, but only attenuated CD11a, cleavage. Neither aprotinin nor pepstatin affected shear-induced CD18 or CD11a cleavage. Notably, dHL60-NCs expressed minimal catB. Thus, multiple cysteine proteases in addition to catB may cleave CD18 on sheared leukocytes. In fact, our findings indicate that multiple non-cysteine proteases also participate in the shear-related cleavage of CD11/CD18 heterodimers. Finally, shear-induced cleavage of CD18 and CD11a by dHL60-NCs was inhibited by fMLP concentrations of at least [Formula: see text]. Collectively, our findings indicate that shear-induced CD11/CD18 cleavage is phenotypic of neutrophilic cells, including those derived from HL60 cells. Moreover, our results verify shear stress as a key anti-inflammatory stimulus for neutrophils under physiologic conditions.

Cathepsin B in eutopic and ectopic endometrial tissues of patients with endometriosis

This study was performed to investigate the expression of cathepsin B mRNA and protein in eutopic and ectopic endometrial tissues of patients with endometriosis and in normal endometrial tissues and to clarify the association between the cathepsin B expression and endometriosis. A total of 40 women with histologically confirmed endometriosis were recruited for study group. For controls, 20 women undergoing operative treatment for uterine myoma, cervical intraepithelial neoplasia (CIN) or benign gynecologic conditions other than endometriosis were recruited. Eutopic endometrial tissues of both groups and ectopic endometrial tissue of study group were collected during the operations. We employed real time reverse transcriptase - polymerase chain reaction (RT-PCR) to quantify mRNA levels of cathepsin B in these tissues. Then, we performed western blot analysis to measure the protein levels of cathepsin B. The expressions of cathepsin B mRNA and protein were significantly higher in both eutopic and ectopic endometrial tissues of women with endometriosis than in endometrial tissues of controls. These data suggest that the higher expression of cathepsin B in the endometrial tissues might be associated with the development of endometriosis. In addition, eutopic endometrium itself with higher expression cathepsin B may play a pivotal role in the histogenesis of endometriosis.

Tyrosine 23 Phosphorylation of Annexin A2 Promotes Proliferation, Invasion, and Stat3 Phosphorylation in the Nucleus of Human Breast Cancer SK-BR-3 Cells

Objective

To investigate the role of tyrosine 23 (Tyr23) phosphorylation of Annexin A2 (Anxa2) in regulating the proliferation and invasion of human breast cancer SK-BR-3 cells.

Methods

A panel of lentivirus plasmids expressing Anxa2-wide type (Ana2-WT), Anxa2-Y23A, and Anxa2-Y23D was generated and infected with SK-BR-3 cells. The monoclonal strains were screened. The expression of Anxa2-WT, Anxa2-Y23A, and Anxa2-Y23D was determined by Western blot analysis. The ability of the cells to proliferate was detected through an MTT [3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] test. Boyden chamber assays were employed to examine migration and invasion abilities. The interaction between Anxa2 and Stat3 was analyzed by immunoprecipitation analyses. Nucleoprotein and cytosolic protein were extracted from SK-BR-3, Anxa2-WT, Anxa2-Y23A, and Anxa2-Y23D cells to analyze the expression and localization of Stat3 phosphorylation.

Results

The monoclonal strains constitutively expressing Anxa2-WT, Anxa2-Y23A, and Anxa2-Y23D were screened. Both Anxa2-WT and Anxa2-Y23D enhanced the proliferation, migration and invasion abilities of SK-BR-3 cells (P<0.05). Immunoprecipitation analysis revealed that Anxa2 and Stat3 interacted with each other, and the expression of Stat3 phosphorylation in the nucleus was enhanced by Anxa2-Y23D.

Conclusions

Tyr23 phosphorylation of Anxa2 promotes the proliferation and invasion of human breast cancer SK-BR-3 cells and the phosphorylation of Stat3 in the nucleus.

Annexin A2 is not a good biomarker for hepatocellular carcinoma in cirrhosis

In China, hepatocellular carcinoma (HCC) usually develops following a long history of chronic hepatitis B infection or cirrhosis. To evaluate the diagnostic role of annexin A2 (ANXA2), a possible tumor marker, in patients with hepatitis B virus (HBV)-related HCC, particularly those with a history of cirrhosis, the present study prospectively enrolled 87 patients with HBV-related HCC (with cirrhosis), 39 patients with HBV-related cirrhosis and 27 healthy controls. The expression levels of serum and tissue ANXA2 were determined using an enzyme-linked immunosorbent assay (ELISA) and immunohistochemical staining, respectively. The serum levels of ANXA2 were significantly elevated in the patients with HCC (median, 567.2 μg/ml; P=0.003) and cirrhosis (median, 414.8 μg/ml; P=0.011) compared with the healthy controls (median, 241.9 μg/ml). However, no significant differences were observed in the serum ANXA2 levels between the patients with HCC and those with cirrhosis. The immunohistochemical staining analysis showed that the healthy controls did not show positive staining, while the number of cases immunoreactive for ANXA2 steadily increased from the liver cirrhosis tissues (20/39, 51.3%) to the non-cancer (53/87, 60.9%) and cancer tissues (68/87, 78.2%). The cancer tissues exhibited a significantly higher ANXA2-positive rate compared with the non-cancer (P=0.013) and liver cirrhosis tissues (P=0.002). Furthermore, marked ANXA2 staining was more prevalent in the cancer tissues (16/87, 18.4%) than the non-cancer (4/87, 4.6%; P=0.004) and liver cirrhosis (1/39, 2.6%; P=0.034) tissues. The sensitivity, specificity and diagnostic accuracy of tissue ANXA2 for HCC in cirrhosis were 78.2, 42.1 and 56.8%, respectively. The ANXA2 expression levels in the serum and cancer tissues were not associated with tumor-free survival or patient survival following liver transplantation. Serum or tissue ANXA2 is not a good diagnostic marker for HCC in HBV-related cirrhosis and is not associated with prognosis.

Dentin phosphoprotein binds annexin 2 and is involved in calcium transport in rat kidney ureteric bud cells

Dentin phosphoprotein (DPP) is the most abundant noncollagenous protein in the dentin, where it plays a major role in the mineralization of dentin. However, we and others have shown that in addition to being present in the dentin, DPP is also present in nonmineralizing tissues like the kidney, lung, and salivary glands, where it conceivably has other functions such as in calcium transport. Because annexins have been implicated as calcium transporters, we examined the relationships between DPP and annexins. In this report, we show that DPP binds to annexin 2 and 6 present in a rat ureteric bud cell line (RUB1). Immunofluorescence studies show that annexin 2 and DPP colocalize in these cells. In addition, DPP and annexin 2 colocalize in the ureteric bud branches of embryonic metanephric kidney. In the RUB1 cells and ureteric bud branches of embryonic kidney, colocalization was restricted to the cell membrane. Studies on calcium influx into RUB cells show that in the presence of anti-DPP, there was a 40% reduction of calcium influx into these cells. We postulate that DPP has different functions in the kidney as compared with the odontoblasts. In the odontoblasts, its primary function is in the extracellular mineralization of dentin, whereas in the kidney it may participate in calcium transport.

Annexin A2: the importance of being redox sensitive

Hydrogen peroxide (H₂O₂) is an important second messenger in cellular signal transduction. H₂O₂-dependent signalling regulates many cellular processes, such as proliferation, differentiation, migration and apoptosis. Nevertheless, H₂O₂ is an oxidant and a major contributor to DNA damage, protein oxidation and lipid peroxidation, which can ultimately result in cell death and/or tumourigenesis. For this reason, cells have developed complex antioxidant systems to scavenge ROS. Recently, our laboratory identified the protein, annexin A2, as a novel cellular redox regulatory protein. Annexin A2 possesses a reactive cysteine residue (Cys-8) that is readily oxidized by H₂O₂ and subsequently reduced by the thioredoxin system, thereby enabling annexin A2 to participate in multiple redox cycles. Thus, a single molecule of annexin A2 can inactivate several molecules of H₂O₂. In this report, we will review the studies detailing the reactivity of annexin A2 thiols and the importance of these reactive cysteine(s) in regulating annexin A2 structure and function. We will also focus on the recent reports that establish novel functions for annexin A2, namely as a protein reductase and as a cellular redox regulatory protein. We will further discuss the importance of annexin A2 redox regulatory function in disease, with a particular focus on tumour progression.

Cathepsin B as a cancer target

INTRODUCTION

Cathepsin B is of significant importance to cancer therapy as it is involved in various pathologies and oncogenic processes in humans. Numerous studies have shown that abnormal regulation of cathepsin B overexpression is correlated with invasive and metastatic phenotypes in cancers. Cathepsin B is normally associated with the lysosomes involved in autophagy and immune response, but its aberrant expression has been shown to lead to cancers.

AREAS COVERED

This review highlights the oncogenic role of cathepsin B, discusses the regulation of cathepsin B in light of oncogenesis, discusses the role of cathepsin B as a signaling molecule, and highlights the therapeutic potential of targeting cathepsin B.

EXPERT OPINION

Targeting cathepsin B alone does not appear to abolish tumor growth, and this is probably because cathepsin B appears to have diverse functions and influence numerous pathways. It is not clear whether global suppression of cathepsin B activity or expression would produce unintended effects or cause the activation or suppression of unwanted pathways. A localized approach for targeting the expression of cathepsin B would be more relevant. Moreover, a combination of targeting cathepsin B with other relevant oncogenic molecules has significant therapeutic potential.

Cathepsin B-cleavable doxorubicin prodrugs for targeted cancer therapy (Review)

Doxorubicin (DOX) is one of the most effective cytotoxic anticancer drugs used for the treatment of hematological malignancies, as well as a broad range of solid tumors. However, the clinical applications of this drug have long been limited due to its severe dose-dependent toxicities. Therefore, DOX derivatives and analogs have been developed to address this issue. A type of DOX prodrug, cleaved by cathepsin B (Cat B), which is highly upregulated in malignant tumors and premalignant lesions, has been developed to achieve a higher DOX concentration in tumor tissue and a lower concentration in normal tissue, so as to enhance the efficacy and reduce toxicity to normal cells. In this review, we focused on Cat B-cleavable DOX prodrugs and discussed the efficacy of these prodrugs, demonstrated by preclinical and clinical developments.

Proteomics-based analysis of invasion-related proteins in malignant gliomas

One of the insidious biological features of gliomas is their potential to extensively invade normal brain tissue, yet molecular mechanisms that dictate this locally invasive behavior remain poorly understood. To investigate the molecular basis of invasion by malignant gliomas, proteomic analysis was performed using a pair of canine glioma subclones - J3T-1 and J3T-2 - that show different invasion phenotypes in rat brains but have similar genetic backgrounds. Two-dimensional protein electrophoresis of whole-cell lysates of J3T-1 (angiogenesis-dependent invasion phenotype) and J3T-2 (angiogenesis-independent invasion phenotype) was performed. Twenty-two distinct spots were recognized when significant alteration was defined as more than 1.5-fold change in spot intensity between J3T-1 and J3T-2. Four proteins that demonstrated increased expression in J3T-1, and 14 proteins that demonstrated increased expression in J3T-2 were identified using liquid chromatography-mass spectrometry analysis. One of the proteins identified was annexin A2, which was expressed at higher levels in J3T-1 than in J3T-2. The higher expression of annexin A2 in J3T-1 was corroborated by quantitative RT-PCR of the cultured cells and immunohistochemical staining of the rat brain tumors. Moreover, immunohistochemical analysis of human glioblastoma specimens showed that annexin A2 was expressed at high levels in the tumor cells that formed clusters around dilated vessels. These results reveal differences in the proteomic profiles between these two cell lines that might correlate with their different invasion profiles. Thus, annexin A2 may be related to angiogenesis-dependent invasion.

The biochemistry and regulation of S100A10: a multifunctional plasminogen receptor involved in oncogenesis

The plasminogen receptors mediate the production and localization to the cell surface of the broad spectrum proteinase, plasmin. S100A10 is a key regulator of cellular plasmin production and may account for as much as 50% of cellular plasmin generation. In parallel to plasminogen, the plasminogen-binding site on S100A10 is highly conserved from mammals to fish. S100A10 is constitutively expressed in many cells and is also induced by many diverse factors and physiological stimuli including dexamethasone, epidermal growth factor, transforming growth factor-α, interferon-γ, nerve growth factor, keratinocyte growth factor, retinoic acid, and thrombin. Therefore, S100A10 is utilized by cells to regulate plasmin proteolytic activity in response to a wide diversity of physiological stimuli. The expression of the oncogenes, PML-RARα and KRas, also stimulates the levels of S100A10, suggesting a role for S100A10 in pathophysiological processes such as in the oncogenic-mediated increases in plasmin production. The S100A10-null mouse model system has established the critical role that S100A10 plays as a regulator of fibrinolysis and oncogenesis. S100A10 plays two major roles in oncogenesis, first as a regulator of cancer cell invasion and metastasis and secondly as a regulator of the recruitment of tumor-associated cells, such as macrophages, to the tumor site.

Screening and identification of lung cancer metastasis-related genes by suppression subtractive hybridization

BACKGROUND AND OBJECTIVE

  Lung cancer metastasis is a complicated process in which multiple stages and multiple genes are involved. There is an urgent need to use new molecular biology techniques to get more systematic information and have a general idea of the molecular events that take place in lung cancer metastasis. The object of this study was to construct the subtracted cDNA libraries of different metastatic potential lung cancer cell lines, NL9980 and L9981, which were established and screened from human lung large cell carcinoma cell line, WCQH-9801.

METHOD

  The forward and reverse subtracted cDNA libraries were constructed in the large cell lung cancer cell lines NL9980 and L9981 with the same heredity background but different metastatic potential, by suppression subtractive hybridization (SSH). The positive clones were preliminarily screened by blue-white colony and precisely identified by PCR. The forward and reverse subtracted libraries were screened and identified by dot blot so as to obtain the clones corresponding to gene segments with differential expression. DNA sequencing was performed to analyze the sequences of differential expression segments, which were then searched and compared using the Basic Local Alignment Search Tool from The National Center for Biotechnology Information NCBI BLAST tools. Quantitative real-time reverse transcription polymerase chain reaction (RT-PCR) and western blotting were performed to confirm the differential expressed genes both on RNA and protein levels.

RESULTS

  The forward and reverse subtracted cDNA libraries of the different large cell lung cancer cell lines with metastatic potential were successfully constructed. With blue-white colony and dot blot, 307 positive clones in the forward subtracted library and 78 positive clones in the reverse subtracted library were obtained. Fifty-five clones were successfully sequenced in the forward subtracted library while 31 clones were successfully sequenced in the reverse subtracted library. One new expressed sequence tag (EST) segment was identified from the reverse subtracted cDNA library and was successfully submitted to GenBank and embodied by GenBank. For the differentially expressed genes between L9981 and NL9980 screened by SSH, four genes, ANXA2, KRT18, ACTG1 was upregulated in L9981 cells compared to NL9980 cells. Annexin A2 (which was encoded by ANXA2), γ-actin (which was encoded by ACTG1), and aldose reductase (which was encoded by AKR1B1) proteins were upregulated in L9981 cells compared to NL9980 cells by western blotting.

CONCLUSION

  The forward and reverse subtracted cDNA libraries of different metastatic potential large cell lung cancer cell lines were successfully constructed by SSH. A series of genes have been screened out to have significantly different expression levels between lung cancer cell lines NL9980 and L9981. A new EST segment that may represent a new metastasis-related gene has been identified. Consistent with the result of SSH, both quantitative real-time RT-PCR and western Blotting confirmed the upregulation of ANXA2, ACTG1 and AKR1B1 in lung cancer cell line L9981 compared with NL9980. These three genes may play important roles in lung cancer metastasis.

Annexin A2 is a novel cellular redox regulatory protein involved in tumorigenesis

Annexins are a structurally related family of calcium and phospholipid-binding proteins that are involved in the regulation of a wide range of molecular and cellular processes. Annexin A2 is unique among the annexins in that it possesses redox sensitive cysteine(s). The ubiquitous and abundant expression of ANXA2 in cells and its reactivity with hydrogen peroxide led us to hypothesize that this protein could play a role in cellular redox regulation. Here we show that ANXA2 protein levels are induced by hydrogen peroxide. Furthermore, depletion of ANXA2 resulted in the elevation of cellular reactive oxygen species (ROS) upon oxidative stress, increased activation of the ROS-induced pro-apoptotic kinases, JNK, p38 and Akt and elevated sensitivity to ROS-mediated cellular damage/death. ANXA2-null mice showed significantly elevated protein oxidation in the liver and lung tissues compared to WT mice. ANXA2 depleted cancer cells showed enhanced cellular protein oxidationconcomitant with decreased tumor growth compared to control cancer cells andboth the oxidation of cellular proteins and tumor growth deficit werereversed by the antioxidant N-acetyl cysteine, indicating that ANXA2 plays akey role in the regulation of cellular redox during tumorigenesis. Ex-vivo human cancer studies showed that up-regulation of the reduced form of ANXA2 is associated with protection of the tumor proteins from oxidation. In summary, our results indicate that ANXA2 plays an important role incellular redox regulation by protecting cells from oxidative stress, aneffect that is particularly important during tumorigenesis.

The prostate cancer bone marrow niche: more than just 'fertile soil'

The hematopoietic stem cell (HSC) niche in the bone marrow has been studied extensively over the past few decades, yet the bone marrow microenvironment that supports the growth of metastatic prostate cancer (PCa) has only been recently considered to be a specialized 'niche' as well. New evidence supports the fact that disseminated tumor cells (DTCs) of PCa actually target the HSC niche, displace the occupant HSCs and take up residence in the pre-existing niche space. This review describes some of the evidence and mechanisms by which DTCs act as molecular parasites of the HSC niche. Furthermore, the interactions between DTCs, HSCs and the niche may provide new targets for niche-directed therapy, as well as insight into the perplexing clinical manifestations of metastatic PCa disease.

Oxidative stress in HPV-driven viral carcinogenesis: redox proteomics analysis of HPV-16 dysplastic and neoplastic tissues

Genital infection by high risk Human Papillomavirus (HR-HPV), although recognized as the main etio-pathogenetic factor of cervical cancer, is not per se sufficient to induce tumour development. Oxidative stress (OS) represents an interesting and under-explored candidate as a promoting factor in HPV-initiated carcinogenesis. To gain insight into the role of OS in cervical cancer, HPV-16 positive tissues were collected from patients with invasive squamous cervical carcinoma, from patients with High Grade dysplastic HPV lesions and from patients with no clinical evidence of HPV lesions. After virological characterization, modulation of proteins involved in the redox status regulation was investigated. ERp57 and GST were sharply elevated in dysplastic and neoplastic tissues. TrxR2 peaked in dysplastic samples while iNOS was progressively reduced in dysplastic and neoplastic samples. By redox proteomic approach, five proteins were found to have increased levels of carbonyls in dysplastic samples respect to controls namely: cytokeratin 6, actin, cornulin, retinal dehydrogenase and GAPDH. In carcinoma samples the peptidyl-prolyl cis-trans isomerase A, ERp57, serpin B3, Annexin 2 and GAPDH were found less oxidized than in dysplastic tissues. HPV16 neoplastic progression seems associated with increased oxidant environment. In dysplastic tissues the oxidative modification of DNA and proteins involved in cell morphogenesis and terminal differentiation may provide the conditions for the neoplastic progression. Conversely cancer tissues seem to attain an improved control on oxidative damage as shown by the selective reduction of carbonyl adducts on key detoxifying/pro-survival proteins.

Live-cell imaging of tumor proteolysis: impact of cellular and non-cellular microenvironment

Our laboratory has had a longstanding interest in how the interactions between tumors and their microenvironment affect malignant progression. Recently, we have focused on defining the proteolytic pathways that function in the transition of breast cancer from the pre-invasive lesions of ductal carcinoma in situ (DCIS) to invasive ductal carcinomas (IDCs). We use live-cell imaging to visualize, localize and quantify proteolysis as it occurs in real-time and thereby have established roles for lysosomal cysteine proteases both pericellularly and intracellularly in tumor proteolysis. To facilitate these studies, we have developed and optimized 3D organotypic co-culture models that recapitulate the in vivo interactions of mammary epithelial cells or tumor cells with stromal and inflammatory cells. Here we will discuss the background that led to our present studies as well as the techniques and models that we employ. This article is part of a Special Issue entitled: Proteolysis 50 years after the discovery of lysosome.

Genomic instability influences the transcriptome and proteome in endometrial cancer subtypes

BACKGROUND

In addition to clinical characteristics, DNA aneuploidy has been identified as a prognostic factor in epithelial malignancies in general and in endometrial cancers in particular. We mapped ploidy-associated chromosomal aberrations and identified corresponding gene and protein expression changes in endometrial cancers of different prognostic subgroups.

METHODS

DNA image cytometry classified 25 endometrioid cancers to be either diploid (n = 16) or aneuploid (n = 9), and all uterine papillary serous cancers (UPSC) to be aneuploid (n = 8). All samples were subjected to comparative genomic hybridization and gene expression profiling. Identified genes were subjected to Ingenuity pathway analysis (IPA) and were correlated to protein expression changes.

RESULTS

Comparative genomic hybridization revealed ploidy-associated specific, recurrent genomic imbalances. Gene expression analysis identified 54 genes between diploid and aneuploid endometrioid carcinomas, 39 genes between aneuploid endometrioid cancer and UPSC, and 76 genes between diploid endometrioid and aneuploid UPSC to be differentially expressed. Protein profiling identified AKR7A2 and ANXA2 to show translational alterations consistent with the transcriptional changes. The majority of differentially expressed genes and proteins belonged to identical molecular functions, foremost Cancer, Cell Death, and Cellular Assembly and Organization.

CONCLUSIONS

We conclude that the grade of genomic instability rather than the histopathological subtype correlates with specific gene and protein expression changes. The identified genes and proteins might be useful as molecular targets for improved diagnostic and therapeutic intervention and merit prospective validation.

Secretory leukocyte protease inhibitor (SLPI) expression and tumor invasion in oral squamous cell carcinoma

Differential expression of secretory leukocyte protease inhibitor (SLPI) impacts on tumor progression. SLPI directly inhibits elastase and other serine proteases, and regulates matrix metalloproteinases, plasminogen activation, and plasmin downstream targets to influence invasion. We examined tissues from human oral squamous cell carcinoma (OSCC) for SLPI expression in parallel with proteases associated with tumor progression and evaluated their relationships using tumor cell lines. Significantly decreased SLPI was detected in OSCC compared to normal oral epithelium. Furthermore, an inverse correlation between SLPI and histological parameters associated with tumor progression, including stage of invasion, pattern of invasion, invasive cell grade, and composite histological tumor score was evident. Conversely, elevated plasmin and elastase were positively correlated with histological parameters of tumor invasion. In addition to its known inhibition of elastase, we identify SLPI as a novel inhibitor of plasminogen activation through its interaction with annexin A2 with concomitant reduced plasmin generation by macrophages and OSCC cell lines. In an in vitro assay measuring invasive activity, SLPI blocked protease-dependent tumor cell migration. Our data suggest that SLPI may possess antitumorigenic activity by virtue of its ability to interfere with multiple requisite proteolytic steps underlying tumor cell invasion and may provide insight into potential stratification of oral cancer according to risk of occult metastasis, guiding treatment strategies.