Identification and functional characterization of annexin A2 in half-smooth tongue sole (Cynoglossus semilaevis)

Annexin A2 (AnxA2), belonging to the annexin family, plays a crucial role in immune responses. In this study, the cDNA of the AnxA2 gene was identified in half-smooth tongue sole, Cynoglossus semilaevis. The transcript of AnxA2 gene in C. semilaevis (CsAnxA2) showed broad tissue distribution, with the highest expression level observed in the gut. CsAnxA2 expression was significantly up-regulated in the intestine, spleen, and kidney tissues following exposure to Shewanella algae. Immunohistochemical staining revealed that CsAnxA2 was predominantly expressed in epithelial cells and significantly elevated after S. algae challenge. Subcellular localization showed that CsAnxA2 was primarily localized in the cytoplasmic compartment. Moreover, proinflammatory cytokines (IL-6, IL-8 and IL-1β) exhibited significant upregulation after CsAnxA2 was overexpressed in vivo. One hundred and fifty-eight CsAnxA2-interacting proteins were captured in the intestinal tissue, showing the top two normalized abundance observed for actin beta (ACTB) and protein S100-A10 (p11). Fifty-four high abundance CsAnxA2-interacting proteins (HIPs) were primary enriched in ten pathways, with the top three significantly enriched pathways being Salmonella infection, glycolysis/gluconeogenesis, and peroxisome proliferator-activated receptor (PPAR) signaling pathway. These results provide valuable information for further investigation into the functional mechanism of AnxA2 in C. semilaevis.

Effect of Annexin A2 on prognosis and sensitivity to immune checkpoint plus tyrosine kinase inhibition in metastatic renal cell carcinoma

BACKGROUND

Immunotherapy (IO) plus tyrosine kinase inhibitor (TKI) therapy is the first-line recommendation for advanced renal cell carcinoma (RCC), but no biomarker has been approved for it. Annexin A2 (ANXA2) can induce immune escape in tumors.

METHODS

Two independent cohorts of advanced RCC treated by IO + TKI were utilized for survival analysis (ZS-MRCC, n = 45; Javelin-101, n = 726). ANXA2 expression was determined by RNA-sequencing. The impact of ANXA2 on the tumor microenvironment was assessed by RNA-sequencing, flow cytometry and immunohistochemistry in two localized RCC datasets (ZS-HRRCC, n = 40; TCGA-KIRC, n = 530).

RESULTS

ANXA2 was upregulated in non-responders of IO + TKI therapy (p = 0.027). High-ANXA2 group showed poor progression-free survival (PFS) in both the ZS-MRCC cohort (HR, 2.348; 95% CI 1.084-5.085; P = 0.025) and the Javelin-101 cohort (HR, 1.472; 95% CI 1.043-2.077; P = 0.027). Multivariate Cox regression determined ANXA2 as an independent prognostic factor (HR, 2.619; 95% CI 1.194-5.746; P = 0.016). High-ANXA2 was correlated with decreased proportion of granzyme B+ CD8+ T cells (Spearman's ρ = - 0.40, P = 0.01), and increased TIM-3+ (Spearman's ρ = 0.43, P < 0.001) and CTLA4+ (Spearman's ρ = 0.49, P < 0.001) tumor-infiltrating lymphocytes. A random forest (RF) score was further build by integrating ANXA2 and immune genes, which stratified patients who would benefit from IO + TKI therapy (low-RF score, IO + TKI vs TKI, HR = 0.453, 95% CI 0.328-0.626; high-RF score, IO + TKI vs TKI, HR = 0.877, 95% CI 0.661-1.165; interaction P = 0.003).

CONCLUSIONS

Upregulated ANXA2 was associated with poor PFS and therapeutic resistance in RCC treated by IO + TKI therapy, and related with T cell exhaustion. The integrated RF score could stratify patients who would benefit from IO + TKI therapy.

ANXA2 (annexin A2) is crucial to ATG7-mediated autophagy, leading to tumor aggressiveness in triple-negative breast cancer cells

Triple-negative breast cancer (TNBC) is associated with a poor prognosis and metastatic growth. TNBC cells frequently undergo macroautophagy/autophagy, contributing to tumor progression and chemotherapeutic resistance. ANXA2 (annexin A2), a potential therapeutic target for TNBC, has been reported to stimulate autophagy. In this study, we investigated the role of ANXA2 in autophagic processes in TNBC cells. TNBC patients exhibited high levels of ANXA2, which correlated with poor outcomes. ANXA2 increased LC3B-II levels following bafilomycin A1 treatment and enhanced autophagic flux in TNBC cells. Notably, ANXA2 upregulated the phosphorylation of HSF1 (heat shock transcription factor 1), resulting in the transcriptional activation of ATG7 (autophagy related 7). The mechanistic target of rapamycin kinase complex 2 (MTORC2) played an important role in ANXA2-mediated ATG7 transcription by HSF1. MTORC2 did not affect the mRNA level of ANXA2, but it was involved in the protein stability of ANXA2. HSPA (heat shock protein family A (Hsp70)) was a potential interacting protein with ANXA2, which may protect ANXA2 from lysosomal proteolysis. ANXA2 knockdown significantly increased sensitivity to doxorubicin, the first-line chemotherapeutic regimen for TNBC treatment, suggesting that the inhibition of autophagy by ANXA2 knockdown may overcome doxorubicin resistance. In a TNBC xenograft mouse model, we demonstrated that ANXA2 knockdown combined with doxorubicin administration significantly inhibited tumor growth compared to doxorubicin treatment alone, offering a promising avenue to enhance the effectiveness of chemotherapy. In summary, our study elucidated the molecular mechanism by which ANXA2 modulates autophagy, suggesting a potential therapeutic approach for TNBC treatment.Abbreviation: ATG: autophagy related; ChIP: chromatin-immunoprecipitation; HBSS: Hanks' balanced salt solution; HSF1: heat shock transcription factor 1; MTOR: mechanistic target of rapamycin kinase; TNBC: triple-negative breast cancer; TFEB: transcription factor EB; TFE3: transcription factor binding to IGHM enhancer 3.

Prognostic significance of annexin A2 and tumor associated macrophages (TAMs) in metastatic renal cell carcinoma and their relation to Sunitinib resistance

Sunitinib, an antiangiogenic tyrosine kinase inhibitor, is the main treatment for metastatic renal cell carcinoma (mRCC). Development of resistance is a major obstacle against therapy success. The aim of this study was to assess annexin A2 and CD163+ tumor associated macrophages (TAMs) immunohistochemical expression in 50 mRCC cases as regard to patients' prognosis and Sunitinib response. Also, to assess the correlation between annexin A2 and TAMs expression. High annexin A2 expression and TAMs density were associated with serum calcium level (P = 0.024 and 0.037, respectively), larger tumor size (P < 0.001), high tumor grade (P = 0.014 and <0.001, respectively), and the presence of tumor necrosis (P < 0.001). High annexin A2 and TAMs expressions were related to shorter patients' overall survival (P = 0.009 and 0.001, respectively) and progression-free survival (P = 0.003 and 0.001, respectively). Annexin A2 was correlated with TAMs density (r = 0.890). Annexin A2 and TAMs are associated with poor prognostic parameters in mRCC patients, including high nuclear grade, increased tumor size, and the presence of tumor necrosis, together with shorter patients' survivals and poor response to Sunitinib. Annexin A2 expression is correlated with TAMs density suggesting immunomodulatory role of annexin A2.

Annexin A2: the missing piece in the puzzle of pathogen-induced damage

Annexin A2 is a Ca²⁺ regulated protein belonging to the Annexin family and is found in the cytoplasm and cell membrane. It can exist in a monomeric form or in a heterotetrameric form with the S100A10 dimer. The research on Annexin A2 in tumours is currently active, and studies on its role in pathogen infection are increasing. Annexin A2 plays a crucial role in the life cycle of viruses by mediating adhesion, internalization, uncoating, transport, and release. In the case of parasites, bacteria, mycoplasma, fungi, and other pathogens, Annexin A2 binds to the ligand on the pathogen, which mediates the pathogen's adhesion to the host cell, ultimately leading to infection and damage to the host. Furthermore, some studies have developed biological or chemical drugs that target Annexin A2, which have demonstrated promising anti-infective effects. Thus, targeting Annexin A2 may present a promising therapeutic approach for the treatment of diverse infectious diseases. In summary, this paper provides an overview of Annexin A2 and its role in various pathogens. It highlights its regulation of pathogen infection and its potential as a therapeutic target for the treatment of infectious diseases.

LppA is a novel plasminogen receptor of Mycoplasma bovis that contributes to adhesion by binding the host extracellular matrix and Annexin A2

Mycoplasma bovis is responsible for various inflammatory diseases in cattle. The prevention and control of M. bovis are complicated by the absence of effective vaccines and the emergence of multidrug-resistant strains, resulting in substantial economic losses worldwide in the cattle industry. Lipoproteins, vital components of the Mycoplasmas cell membrane, are deemed potent antigens for eliciting immune responses in the host upon infection. However, the functions of lipoproteins in M. bovis remain underexplored due to their low sequence similarity with those of other bacteria and the scarcity of genetic manipulation tools for M. bovis. In this study, the lipoprotein LppA was identified in all examined M. bovis strains. Utilizing immunoelectron microscopy and Western blotting, it was observed that LppA localizes to the surface membrane. Recombinant LppA demonstrated dose-dependent adherence to the membrane of embryonic bovine lung (EBL) cells, and this adhesion was inhibited by anti-LppA serum. In vitro binding assays confirmed LppA's ability to associate with fibronectin, collagen IV, laminin, vitronectin, plasminogen, and tPA, thereby facilitating the conversion of plasminogen to plasmin. Moreover, LppA was found to bind and enhance the accumulation of Annexin A2 (ANXA2) on the cell membrane. Disrupting LppA in M. bovis significantly diminished the bacterium's capacity to adhere to EBL cells, underscoring LppA's function as a bacterial adhesin. In conclusion, LppA emerges as a novel adhesion protein that interacts with multiple host extracellular matrix proteins and ANXA2, playing a crucial role in M. bovis's adherence to host cells and dissemination. These insights substantially deepen our comprehension of the molecular pathogenesis of M. bovis.

Silencing AHNAK promotes nasopharyngeal carcinoma progression by upregulating the ANXA2 protein

PURPOSE

Nasopharyngeal carcinoma (NPC) is an aggressive head and neck disease with a high incidence of distant metastases. Enlargeosomes are cytoplasmic organelles marked by, desmoyokin/AHNAK. This study aimed to evaluate the expression of AHNAK in NPC and its effect on enlargeosomes and to investigate the correlation between AHNAK expression levels and clinical NPC patient characteristics.

METHODS

Primary nasopharyngeal carcinoma (NPC) and NPC specimens were evaluated by analyzing public data, and immunohistochemistry. Systematic in vitro and in vivo experiments were performed using different NPC-derived cell lines and mouse models.

RESULTS

In this study, we detected AHNAK and Annexin A2(ANXA2), a protein coating the surface of enlargeosomes, in NPC samples. We found that AHNAK was down-regulated. Down-regulation of AHNAK was associated with poor overall survival in NPC patients. Moreover, transcription factor FOSL1-mediated transcriptional repression was responsible for the low expression of AHNAK by recruiting EZH2. Whereas Annexin A2 was upregulated in human NPC tissues. Upregulation of Annexin A2 was associated with lymph node metastasis and distant metastasis in NPC patients. Functional studies confirmed that silencing of AHNAK enhanced the growth, invasion, and metastatic properties of NPC cells both in vitro and in vivo. In terms of mechanism, loss of AHNAK led to an increase of annexin A2 protein level in NPC cells. Silencing ANXA2 restored NPC cells' migrative and invasive ability upon loss of AHNAK.

CONCLUSION

Here, we report AHNAK as a tumor suppressor in NPC, which may act through annexin A2 oncogenic signaling in enlargeosome, with potential implications for novel approaches to NPC treatment.

The intricate role of annexin A2 in kidney: a comprehensive review

Annexin A2 (Anxa2) is a calcium (Ca2+)-regulated phospholipid binding protein composed of a variable N-terminus and a conserved core domain. This protein has been widely found in many tissues and fluids, including tubule cells, glomerular epithelial cells, renal vessels, and urine. In acute kidney injury, the expression level of this protein is markedly elevated in response to acute stress. Moreover, Anxa2 is a novel biomarker and potential therapeutic target with prognostic value in chronic kidney disease. In addition, Anxa2 is associated not only with clear-cell renal cell carcinoma differentiation but also the formation of calcium-related nephrolithiasis. In this review, we discuss the characteristics and functions of Anxa2 and focus on recent reports on the role of Anxa2 in the kidney, which may be useful for future research.

A de novo missense mutation in MPP2 confers an increased risk of Vogt-Koyanagi-Harada disease as shown by trio-based whole-exome sequencing

Vogt-Koyanagi-Harada (VKH) disease is a leading cause of blindness in young and middle-aged people. However, the etiology of VKH disease remains unclear. Here, we performed the first trio-based whole-exome sequencing study, which enrolled 25 VKH patients and 50 controls, followed by a study of 2081 VKH patients from a Han Chinese population to uncover detrimental mutations. A total of 15 de novo mutations in VKH patients were identified, with one of the most important being the membrane palmitoylated protein 2 (MPP2) p.K315N (MPP2-N315) mutation. The MPP2-N315 mutation was highly deleterious according to bioinformatic predictions. Additionally, this mutation appears rare, being absent from the 1000 Genome Project and Genome Aggregation Database, and it is highly conserved in 10 species, including humans and mice. Subsequent studies showed that pathological phenotypes and retinal vascular leakage were aggravated in MPP2-N315 mutation knock-in or MPP2-N315 adeno-associated virus-treated mice with experimental autoimmune uveitis (EAU). In vitro, we used clustered regularly interspaced short palindromic repeats (CRISPR‒Cas9) gene editing technology to delete intrinsic MPP2 before overexpressing wild-type MPP2 or MPP2-N315. Levels of cytokines, such as IL-1β, IL-17E, and vascular endothelial growth factor A, were increased, and barrier function was destroyed in the MPP2-N315 mutant ARPE19 cells. Mechanistically, the MPP2-N315 mutation had a stronger ability to directly bind to ANXA2 than MPP2-K315, as shown by LC‒MS/MS and Co-IP, and resulted in activation of the ERK3/IL-17E pathway. Overall, our results demonstrated that the MPP2-K315N mutation may increase susceptibility to VKH disease.

Collagen-I influences the post-translational regulation, binding partners and role of Annexin A2 in breast cancer progression

Introduction

The extracellular matrix (ECM) has been heavily implicated in the development and progression of cancer. We have previously shown that Annexin A2 is integral in the migration and invasion of breast cancer cells and in the clinical progression of ER-negative breast cancer, processes which are highly influenced by the surrounding tumor microenvironment and ECM.

Methods

We investigated how modulations of the ECM may affect the role of Annexin A2 in MDA-MB-231 breast cancer cells using western blotting, immunofluorescent confocal microscopy and immuno-precipitation mass spectrometry techniques.

Results

We have shown that the presence of collagen-I, the main constituent of the ECM, increases the post-translational phosphorylation of Annexin A2 and subsequently causes the translocation of Annexin A2 to the extracellular surface. In the presence of collagen-I, we identified fibronectin as a novel interactor of Annexin A2, using mass spectrometry analysis. We then demonstrated that reducing Annexin A2 expression decreases the degradation of fibronectin by cancer cells and this effect on fibronectin turnover is increased according to collagen-I abundance.

Discussion

Our results suggest that Annexin A2's role in promoting cancer progression is mediated by collagen-I and Annexin A2 maybe a therapeutic target in the bi-directional cross-talk between cancer cells and ECM remodeling that supports metastatic cancer progression.

Interactions and conformational changes of annexin A2/p11 heterotetramer models on a membrane: a molecular dynamics study

Ca2+-dependent membrane-binding by the Annexin A2/p11 heterotetramer (A2t) plays an important role in various biological processes including fibrinogen activation and exocytosis in neuroendocrine cells. Two models where A2t associates with a single membrane surface were generated and used to perform molecular dynamics simulations. The first model mimics initial A2t-membrane binding through both Annexin A2 (A2) subunits of A2t (TS model) while the second model mimics A2t-binding through a single A2 subunit (OS model). Conformational changes were summarized using principal component analysis (PCA), simulation snapshots, and distance plots from the simulations. The full TS model, including the p11 dimer, fully associates with the membrane adopting a stable structure with little conformational variation as evidence by PCA. The unassociated subunits of the OS model moved toward the membrane. The molecular mechanics/Generalized-Born surface area (MMGBSA) method was applied to investigate the energetics of the models. The MMGBSA results demonstrated that R63 of p11 was the primary contributor to the p11-membrane interaction. The TS model results were both consistent with those found in the literature and provide novel insights about the specific residues driving the A2t-membrane interaction. Additionally, it represents the most complete model of A2t on the membrane surface available.Communicated by Ramaswamy H. Sarma.

Upregulation of HDAC9 in hippocampal neurons mediates depression-like behaviours by inhibiting ANXA2 degradation

Major depressive disorder (MDD) is a pervasive and devastating mental disease. Broad spectrum histone deacetylase (HDAC) inhibitors are considered to have potential for the treatment of depressive phenotype in mice. However, due to its non-specific inhibition, it has extensive side effects and can not be used in clinical treatment of MDD. Therefore, finding specific HDAC subtypes that play a major role in the etiology of MDD is the key to develop corresponding specific inhibitors as antidepressants in the future. Copy number variation in HDAC9 gene is thought to be associated with the etiology of some psychiatric disorders. Herein, we found that HDAC9 was highly expressed in the hippocampus of chronic restraint stress (CRS) mouse model of depression. Upregulation of HDAC9 expression in hippocampal neurons of mice induced depression-like phenotypes, including anhedonia, helplessness, decreased dendritic spine density, and neuronal hypoexcitability. Moreover, knockdown or knockout of HDAC9 in hippocampal neurons alleviated depression-like phenotypes caused by chronic restraint stress (CRS) in WT mice. Importantly, using immunoprecipitation-mass spectrometry (IP-MS), we further found that Annexin A2 (ANXA2) was coupled to and deacetylated by HDAC9. This coupling resulted in the inhibition of ubiquitinated ANXA2 degradation and then mediates depression-like behavior. Overall, we discovered a previously unrecognized role for HDAC9 in hippocampal neurons in the pathogenesis of depression, indicating that inhibition of HDAC9 might be a promising clinical strategy for the treatment of depressive disorders.

Ca2+ ions facilitate the organization of the Annexin A2/S100A10 heterotetramer

Annexin A2 (A2) is a member of the Annexin family, which contains Ca2+ -regulated phospholipid-binding proteins. Annexins associate with S100 proteins to form heterotetramers. The A2/S100A10 heterotetramer (A2t) is the most extensively studied of these heterotetramers. It induces membrane microdomain formation, causes membrane budding, and facilitates proliferation of some cancers. In this work, the first molecular dynamics (MD) study on the complete A2t of 868 amino acids was performed. MD trajectories of more than 600 ns each were generated for complete A2t complexes with and without Ca2+ ions. The outward extension of membrane-binding residues A2-K279 and A2-K281 was shown to be inhibited in the absence of Ca2+ as they were captured by Ca2+ -binding residue D322. F-actin binding residue A2-D339 was observed to occupy either an exposed or buried state in the absence of Ca2+ , while it only occupied the buried state in the presence of Ca2+ . The observed motions of the A2t subunits are highly organized with a strongly correlated central region which is negatively correlated with the periphery of the complex. The central region contains the S100A10 (p11) dimer, A2-N, and A2-I, while the periphery contains A2-II, A2-III, and A2-IV. Novel interactions between A2 and p11 were identified. A2 residues outside of A2-N (K80, R77, E82, and R145) had strong interactions with p11. Residue R145 of A2 may have a significant effect on the dynamics of the system, with its interaction resulting in asymmetric motions of A2. The presented results provide novel insights to inform future experimental studies.

Açaí (Euterpe oleracea Mart.) Seed Oil Exerts a Cytotoxic Role over Colorectal Cancer Cells: Insights of Annexin A2 Regulation and Molecular Modeling

Açaí, Euterpe oleracea Mart., is a native plant from the Amazonian and is rich in several phytochemicals with anti-tumor activities. The aim was to analyze the effects of açaí seed oil on colorectal adenocarcinoma (ADC) cells. In vitro analyses were performed on CACO-2, HCT-116, and HT-29 cell lines. The strains were treated with açaí seed oil for 24, 48, and 72 h, and cell viability, death, and morphology were analyzed. Molecular docking was performed to evaluate the interaction between the major compounds in açaí seed oil and Annexin A2. The viability assay showed the cytotoxic effect of the oil in colorectal adenocarcinoma cells. Acai seed oil induced increased apoptosis in CACO-2 and HCT-116 cells and interfered with the cell cycle. Western blotting showed an increased expression of LC3-B, suggestive of autophagy, and Annexin A2, an apoptosis regulatory protein. Molecular docking confirmed the interaction of major fatty acids with Annexin A2, suggesting a role of açaí seed oil in modulating Annexin A2 expression in these cancer cell lines. Our results suggest the anti-tumor potential of açaí seed oil in colorectal adenocarcinoma cells and contribute to the development of an active drug from a known natural product.

The flavagline FL3 interferes with the association of Annexin A2 with the eIF4F initiation complex and transiently stimulates the translation of annexin A2 mRNA

Introduction: Annexin A2 (AnxA2) plays a critical role in cell transformation, immune response, and resistance to cancer therapy. Besides functioning as a calcium- and lipidbinding protein, AnxA2 also acts as an mRNA-binding protein, for instance, by interacting with regulatory regions of specific cytoskeleton-associated mRNAs. Methods and Results: Nanomolar concentrations of FL3, an inhibitor of the translation factor eIF4A, transiently increases the expression of AnxA2 in PC12 cells and stimulates shortterm transcription/translation of anxA2 mRNA in the rabbit reticulocyte lysate. AnxA2 regulates the translation of its cognate mRNA by a feed-back mechanism, which can partly be relieved by FL3. Results obtained using the holdup chromatographic retention assay results suggest that AnxA2 interacts transiently with eIF4E (possibly eIF4G) and PABP in an RNA-independent manner while cap pulldown experiments indicate a more stable RNA-dependent interaction. Short-term (2 h) treatment of PC12 cells with FL3 increases the amount of eIF4A in cap pulldown complexes of total lysates, but not of the cytoskeletal fraction. AnxA2 is only present in cap analogue-purified initiation complexes from the cytoskeletal fraction and not total lysates confirming that AnxA2 binds to a specific subpopulation of mRNAs. Discussion: Thus, AnxA2 interacts with PABP1 and subunits of the initiation complex eIF4F, explaining its inhibitory effect on translation by preventing the formation of the full eIF4F complex. This interaction appears to be modulated by FL3. These novel findings shed light on the regulation of translation by AnxA2 and contribute to a better understanding of the mechanism of action of eIF4A inhibitors.

Grouper annexin A2 affects RGNNV by regulating the host immune response

Annexin A2 (AnxA2) is ubiquitous in vertebrates and has been identified as a multifunctional protein participating in a series of biological processes, such as endocytosis, exocytosis, signal transduction, transcription regulation, and immune responses. However, the function of AnxA2 in fish during virus infection still remains unknown. In this study, we identified and characterized AnxA2 (EcAnxA2) in Epinephelus coioides. EcAnxA2 encoded a 338 amino acids protein with four identical annexin superfamily conserved domains, which shared high identity with other AnxA2 of different species. EcAnxA2 was widely expressed in different tissues of healthy groupers, and its expression was significantly increased in grouper spleen cells infected with red-spotted grouper nervous necrosis virus (RGNNV). Subcellular locatio n analyses showed that EcAnxA2 diffusely distributed in the cytoplasm. After RGNNV infection, the spatial distribution of EcAnxA2 was unaltered, and a few EcAnxA2 co-localized with RGNNV during the late stage of infection. Furthermore, overexpression of EcAnxA2 significantly increased RGNNV infection, and knockdown of EcAnxA2 reduced RGNNV infection. In addition, overexpressed EcAnxA2 reduced the transcription of interferon (IFN)-related and inflammatory factors, including IFN regulatory factor 7 (IRF7), IFN stimulating gene 15 (ISG15), melanoma differentiation related gene 5 (MDA5), MAX interactor 1 (Mxi1) laboratory of genetics and physiology 2 (LGP2), IFN induced 35 kDa protein (IFP35), tumor necrosis factor receptor-associated factor 6 (TRAF6) and interleukin 6 (IL-6). The transcription of these genes was up-regulated when EcAnxA2 was inhibited by siRNA. Taken together, our results showed that EcAnxA2 affected RGNNV infection by down-regulating the host immune response in groupers, which provided new insights into the roles of AnxA2 in fish during virus infection.

Proline/serine-rich coiled-coil protein 1 inhibits macrophage inflammation and delays atherosclerotic progression by binding to Annexin A2

BACKGROUND

Atherosclerosis (AS), the main pathological basis of life-threatening cardiovascular disease, is essentially caused by chronic macrophage inflammation. Overexpression of proline/serine-rich coiled-coil protein 1 (PSRC1) reduces macrophage inflammatory responses and delays AS development. However, the exact mechanism of PSRC1 is unclear.

METHODS

Proteins interacting with PSRC1 were screened by proteomics in RAW264.7 cells, followed by RT-qPCR, immunoprecipitation and immunofluorescence to explore the specific mechanistic pathways affecting inflammation. CRISPR-Cas9 constructs for PSRC1^-/- ApoE^-/- (DKO) mice and high-fat diet-fed ApoE^-/- and DKO mice were used for AS models for in vivo experiments. Upstream transcription factors of PSRC1 were predicted by ATAC-seq, ChIP-seq and UCSC, and the regulatory mechanism was verified by ChIP-qPCR and dual luciferase assays. Peripheral blood serum and monocytes were collected from coronary artery disease (CAD) patients and non-CAD patients.

RESULTS

Increased binding of ANXA2 to PSRC1 in macrophages under oxidized low-density lipoprotein stimulation and decreased release of ANXA2 to the extracellular compartment were observed. Knockdown of ANXA2 in AS model mice delayed AS progression. Knockdown of ANXA2 in DKO mice reversed the AS-promoting effect of PSRC1 knockdown. Mechanistically, ANXA2 promotes STAT3 phosphorylation, which in turn promotes inflammatory responses. In addition, SP1 is a PSRC1 upstream repressive transcription factor, and the SP1 inhibitor mithramycin (Mith) elevated PSRC1 expression and exerted anti-AS effects in AS model mice. Patients with CAD had considerably greater serum levels of ANXA2 than those without CAD, and Mith reduced the secretion of ANXA2 in peripheral blood monocytes of CAD patients.

CONCLUSION

In macrophages, PSRC1 can interact with ANXA2 to inhibit its extracellular release and delay AS development. SP1 is an upstream transcription factor of PSRC1 and inhibits the transcription of PSRC1. The SP1 inhibitor Mith can elevate PSRC1 levels and slow AS progression while reducing ANXA2 release from monocytes in CAD patients. Mith is expected to be a new agent for AS treatment.

Isoliquiritigenin alleviates the development of alcoholic liver fibrosis by inhibiting ANXA2

The study aimed to investigate the effect of isoliquiritigenin (ISL) on model of alcoholic liver fibrosis (ALF). C57BL/6 mice were used to establish animal model of ALF, HSC-T6 cells were used to establish alcohol-activated cell model, and tandem mass tag (TMT) assays were used to analyze the proteome. The results showed that ISL obviously alleviated hepatic fibrosis in model mice. ISL visually improved the area of liver pathological stasis and deposition of fibrillar collagen (Sirius Red staining, Masson staining), inhibited the mRNA expression levels of interleukin 6 (IL-6), tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β) in liver tissues. ISL down-regulated the mRNA expression levels of IL-6 and transforming growth factor-β1(TGF-β1) in activated hepatic stellate cells (HSCs). And ISL significantly reduced annexin A2 (ANXA2) in vitro detected by TMT proteomics technology. Interestingly, it was found for the first time that ISL could inhibit ANXA2 expression both in vivo and in vitro, block the sphingosine kinases (SPHKs)/sphingosine-1-phosphate (S1P)/interleukin 17 (IL-17) signaling pathway and regulate the expression of α-smooth muscle actin (α-SMA) by inhibiting the phosphorylation of signal transducer and activator of transcription 3 (STAT3) at the downstream signal to finally reverse HSCs activation and hepatic fibrosis. Thus, we demonstrated that ISL is a drug monomer with notable anti-hepatic fibrosis activity.

Direct and Indirect Effects of Filamin A on Tau Pathology in Neuronal Cells

In Alzheimer disease (AD), Tau, an axonal microtubule-associated protein, becomes hyperphosphorylated, detaches from microtubules, accumulates, and self-aggregates in the somatodendritic (SD) compartment. The accumulation of hyperphosphorylated and aggregated Tau is also seen in other neurodegenerative diseases such as frontotemporal lobar degeneration (FTLD-Tau). Previous studies reported a link between filamin A (FLNA), an actin-binding protein found in the SD compartment, and Tau pathology. In the present study, we further explored this link. We confirmed the interaction of Tau with FLNA in neuroblastoma 2a (N2a) cells. This interaction was mediated by a domain located between the 157 and 383 amino acids (a.a.) of Tau. Our results also revealed that the overexpression of FLNA resulted in an intracellular accumulation of wild-type Tau and Tau mutants (P301L, V337M, and R406W) in N2a cells. Tau phosphorylation and cleavage by caspase-3 but not its aggregation were increased upon FLNA overexpression in N2a cells. In the parietal cortex of AD brain, insoluble FLNA was increased compared to control brain, but it did not correlate with Tau pathology. Interestingly, Tau binding to microtubules and F-actin was preserved upon FLNA overexpression in N2a cells. Lastly, our results revealed that FLNA also induced the accumulation of annexin A2, a Tau interacting partner involved in its axonal localization. Collectively, our data indicated that in Tauopathies, FLNA could contribute to Tau pathology by acting on Tau and annexin A2.

Annexin A2 promotes angiogenesis after ischemic stroke via annexin A2 receptor - AKT/ERK pathways

Promoting angiogenesis to restore circulation to the ischemic tissue is still an important therapeutic target in stroke. Our group and others previously reported that the Ca²⁺-regulated, phospholipid-and membrane-binding protein-Annexin A2 (ANXA2) functions in cerebrovascular integrity and retinal neoangiogenesis. Here, we hypothesized that ANXA2 may regulate angiogenesis after stroke, ultimately improve neurological outcomes. Compared with wild type (WT) mice, the density of microvessels in brain and the number of new vessels sprouting from aortic ring were significantly increased in Anxa2 knock-in (Anxa2 KI) mice. After focal cerebral ischemia, proliferation of brain endothelial cells in Anxa2 KI mice was significantly elevated at 7 days post-stroke, which further improved behavioral recovery. To assess the pro-angiogenic mechanisms of ANXA2, we used brain endothelial cells cultures to investigate its effects on cell tube-numbers and migration. Recombinant ANXA2 increased tube-numbers and migration of brain endothelial cells either under normal condition or after oxygen glucose deprivation (OGD) injury. Co-immunoprecipitation experiments demonstrated that these protective effects of recombinant ANXA2 were regulated by interaction with ANXA2 receptor (A2R), a protein found in cancer cells that can interact with ANXA2 to promote cell migration and proliferation, and the ability of ANXA2-A2R to activate AKT/ERK pathways. Inhibition of AKT/ERK diminished recombinant ANXA2-induced angiogenesis in vitro. Taken together, our study indicates that ANXA2 might be involved in angiogenesis after ischemic stroke. Further investigation of ANXA2-A2R will provide a new therapeutic target for stroke.

Annexin A2 modulates phospholipid membrane composition upstream of Arp2 to control angiogenic sprout initiation

The intersection of protein and lipid biology is of growing importance for understanding how cells address structural challenges during adhesion and migration. While protein complexes engaged with the cytoskeleton play a vital role, support from the phospholipid membrane is crucial for directing localization and assembly of key protein complexes. During angiogenesis, dramatic cellular remodeling is necessary for endothelial cells to shift from a stable monolayer to invasive structures. However, the molecular dynamics between lipids and proteins during endothelial invasion are not defined. Here, we utilized cell culture, immunofluorescence, and lipidomic analyses to identify a novel role for the membrane binding protein Annexin A2 (ANXA2) in modulating the composition of specific membrane lipids necessary for cortical F-actin organization and adherens junction stabilization. In the absence of ANXA2, there is disorganized cortical F-actin, reduced junctional Arp2, excess sprout initiation, and ultimately failed sprout maturation. Furthermore, we observed reduced filipin III labeling of membrane cholesterol in cells with reduced ANXA2, suggesting there is an alteration in phospholipid membrane dynamics. Lipidomic analyses revealed that 42 lipid species were altered with loss of ANXA2, including an accumulation of phosphatidylcholine (16:0_16:0). We found that supplementation of phosphatidylcholine (16:0_16:0) in wild-type endothelial cells mimicked the ANXA2 knock-down phenotype, indicating that ANXA2 regulated the phospholipid membrane upstream of Arp2 recruitment and organization of cortical F-actin. Altogether, these data indicate a novel role for ANXA2 in coordinating events at endothelial junctions needed to initiate sprouting and show that proper lipid modulation is a critical component of these events.

Serum Annexin A2 concentrations are increased in patients with diabetic cardiomyopathy and are linked to cardiac dysfunctions

BACKGROUND

Diabetic cardiomyopathy (DbCM) is defined as the existence of abnormal myocardial structure and functions in the absence of other cardiac diseases, such as coronary artery disease, hypertension, and significant valvular disease, in individuals with diabetes. Although abundant epidemic evidence demonstrates that diabetes is independently associated with the risk of developing heart failure, DbCM is not normally diagnosed in clinical practices due to its exclusive diagnosis, and no diagnostic biomarker was applied in a clinical test.

METHODS

To detect the concentrations of serum Annexin A2 in non-diabetic subjects, type 2 diabetic (T2DM) patients with or without DbCM, and analyzed its relationship to parameters of cardiac functions, glucose, lipid metabolism, and renal functions. 266 eligible participants were included and were divided into 3 groups including non-diabetic subjects (NGR), T2DM patients without DbCM (T2DM group), and the DbCM group. Echocardiography, coronary computed tomography angiography, electrocardiogram, blood pressure, thyroid function, and clinical and other biochemical parameters were measured in all participants.

RESULTS

Serum Annexin A2 concentrations were higher in DbCM (P < 0.05) and T2DM (P < 0.05) groups compared with the NGR group, especially in DbCM patients. Correlation analysis showed that serum Annexin A2 levels were negatively associated with left ventricular (LV) ejection fraction (EF), LV fractional shortening (FS), the ratio of early (E-wave) and late (A-wave) LV diastolic filling velocities (E/A ratio), and estimated glomerular filtration rate (eGFR), and were positively correlated with age, blood urea nitrogen (BUN) and creatinine (Cr) (all P < 0.05). Multiple logistical regression analyses revealed that serum in both the second and the third tertiles of Annexin A2 concentration were significantly associated with DbCM. E/A ratio is the independent factor for Annexin A2 concentration when adjusted for LV FS%, BUN, and Cr.

CONCLUSIONS

Circulating Annexin A2 concentrations might be induced in DbCM patients and were negatively associated with cardiac systolic and diastolic functions, which suggested it might be a predictor of early diagnosis in DbCM and might be a potential therapeutic target for DbCM.

Higher Expression of Annexin A2 in Metastatic Bladder Urothelial Carcinoma Promotes Migration and Invasion

In this study, we aim to evaluate the significance of AnxA2 in BLCA and establish its metastatic role in bladder cancer cells. Analysis of TCGA data showed that AnxA2 mRNA expression was significantly higher in BLCA tumors than in normal bladder tissues. High mRNA expression of AnxA2 in BLCA was significantly associated with high pathological grades and stages, non-papillary tumor histology, and poor overall survival (OS), progression-free survival (PFS), and diseases specific survival (DSS). Similarly, we found that AnxA2 expression was higher in bladder cancer cells derived from high-grade metastatic carcinoma than in cells derived from low-grade urothelial carcinoma. AnxA2 expression significantly mobilized to the surface of highly metastatic bladder cancer cells compared to cells derived from low-grade tumors and associated with high plasmin generation and AnxA2 secretion. In addition, the downregulation of AnxA2 cells significantly inhibited the proliferation, migration, and invasion in bladder cancer along with the reduction in proangiogenic factors and cytokines such as PDGF-BB, ANGPT1, ANGPT2, Tie-2, bFGF, GRO, IL-6, IL-8, and MMP-9. These findings suggest that AnxA2 could be a promising biomarker and therapeutic target for high-grade BLCA.

Annexin A2 (AnxA2) association with the clinicopathological data in different breast cancer subtypes: A possible role for AnxA2 in tumor heterogeneity and cancer progression

BACKGROUND

Breast cancer is a highly heterogeneous type of neoplasia with molecular and biochemical alterations in the ductal epithelium. AnxA2 has a diverse functions and through intracellular interaction with other molecules promotes carcinogenesis.

AIMS

To study the possible involvement of AnxA2 in breast cancer heterogeneity and cancer progression.

PATIENTS AND METHODS

Tumor tissue and serum were obtained from different breast cancer subtypes. Tumor tissues were processed for histopathological studies. AnxA2 levels were assessed in the tissues by H scoring and in the serum by ELISA. AnxA2 levels were correlated with HER2 and Ki67 and with clinicopathological data. Normal breast tissues and serum from healthy subjects were used as controls.

RESULTS

AnxA2 showed a peculiar distribution in tumor tissues and nearby interstitial tissues. Pattern of expressions varied in different subtypes with the highest expression in triple negative subtype. Tissue and serum AnxA2 showed significant co-upregulations in breast cancer. Moreover, they showed positive correlations with HER2 and Ki67 and associations with clinicopathological data including cancer staging and lymph node metastasis.

CONCLUSION

For the best of our knowledge this is the first study showing correlation between AnxA2, the proposed prognostic marker and the well-established tumor markers; HER2 and Ki67. AnxA2 might contribute to breast cancer heterogeneity and is associated with poor prognosis. AnxA2 might be a prognostic marker and an additional marker for breast cancer grading and clinical staging. Interestingly, tissue and serum AnxA2 showed a strong correlation. Thus, assessing serum AnxA2 can be a noninvasive prognostic tool.

E3 ubiquitin ligase Trim33 ubiquitylates Annexin A2 to promote NF-κB induced skin inflammation in psoriasis

BACKGROUND

Tripartite motif-containing protein 33, a member of the TRIM E3 ligase family, is shown to be involved in tumorigenesis, cell proliferation and inflammation. Alteration of several TRIM family proteins in psoriatic epidermis has been shown to participate in psoriasis pathogenesis. However, little is known about Trim33 expression and its role in psoriasis.

OBJECTIVES

To examine the expression and biological roles of Trim33 in psoriatic process, with a focus on identifying its novel substrates in psoriatic keratinocytes.

METHODS

Gene expression of Trim33 in biopsies from psoriasis patients compared with healthy volunteers was analysed by quantitative real-time polymerase chain reaction (qPCR) and immunofluorescence (IF). Identification of Trim33 substrates were performed using immunoprecipitation combined with mass spectrometry. Protein expression and localization were assessed by immunoblotting and immunofluorescence. Expression of cytokines was analysed with qPCR.

RESULTS

qPCR and IF analysis revealed increased expression of Trim33 in psoriatic epidermis. Overexpression of Trim33 promoted the expression of psoriasis-related proinflammatory cytokines IL-6, IL-1β and NLRP3 inflammasome. Intriguingly, Trim33 induced lysine 63 (K63)-linked ubiquitination of Annexin A2 (Anxa2), which promoted its interaction with p50/p65 subunits of NF-κB, favoured the retention of p50/p65 in the nucleus and promoted the expression of inflammation-related NF-κB downstream genes.

CONCLUSIONS

Our study highlights the upregulation of Trim33 in psoriatic epidermis and its pivotal role in promoting the inflammation of keratinocytes by Anxa2/NF-κB pathway. Our findings imply that Trim33 might be further explored as potential target for psoriasis treatment.

Annexin A2 (ANXA2) regulates the transcription and alternative splicing of inflammatory genes in renal tubular epithelial cells

Background

Renal inflammation plays a crucial role during the progression of Chronic kidney disease (CKD), but there is limited research on hub genes involved in renal inflammation. Here, we aimed to explore the effects of Annexin A2 (ANXA2), a potential inflammatory regulator, on gene expression in human proximal tubular epithelial (HK2) cells. RNA-sequencing and bioinformatics analysis were performed on ANXA2-knockdown versus control HK2 cells to reveal the differentially expressed genes (DEGs) and regulated alternative splicing events (RASEs). Then the DEGs and RASEs were validated by qRT-PCR.

Results

A total of 220 upregulated and 171 downregulated genes related to ANXA2 knockdown were identified. Genes enriched in inflammatory response pathways, such as interferon-mediated signaling, cytokine-mediated signaling, and nuclear factor κB signaling, were under global transcriptional and alternative splicing regulation by ANXA2 knockdown. qRT-PCR confirmed ANXA2-regulated transcription of chemokine gene CCL5, as well as interferon-regulating genes ISG15, IFI6, IFI44, IFITM1, and IRF7, in addition to alternative splicing of inflammatory genes UBA52, RBCK1, and LITAF.

Conclusions

The present study indicated that ANXA2 plays a role in inflammatory response in HK2 cells that may be mediated via the regulation of transcription and alternative splicing of inflammation-related genes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08748-6.

Inhibition of ANXA2 regulated by SRF attenuates the development of severe acute pancreatitis by inhibiting the NF-κB signaling pathway

BACKGROUND

Acute pancreatitis (AP) is an inflammatory process of the pancreas resulting from biliary obstruction or alcohol consumption. Approximately, 10-20% of AP can evolve into severe AP (SAP). In this study, we sought to explore the physiological roles of the transcription factor serum response factor (SRF), annexin A2 (ANXA2), and nuclear factor-kappaB (NF-κB) in SAP.

METHODS

C57BL/6 mice and rat pancreatic acinar cells (AR42J) were used to establish an AP model in vivo and in vitro by cerulein with or without lipopolysaccharide (LPS). Production of pro-inflammatory cytokines (IL-1β and TNF-α) were examined by ELISA and immunoblotting analysis. Hematoxylin and eosin (HE) staining and TUNEL staining were performed to evaluate pathological changes in the course of AP. Apoptosis was examined by flow cytometric and immunoblotting analysis. Molecular interactions were tested by dual luciferase reporter, ChIP, and Co-IP assays.

RESULTS

ANXA2 was overexpressed in AP and correlated to the severity of AP. ANXA2 knockdown rescued pancreatic acinar cells against inflammation and apoptosis induced by cerulein with or without LPS. Mechanistic investigations revealed that SRF bound with the ANXA2 promoter region and repressed its expression. ANXA2 could activate the NF-κB signaling pathway by inducing the nuclear translocation of p50. SRF-mediated transcriptional repression of ANXA2-protected pancreatic acinar cells against AP-like injury through repressing the NF-κB signaling pathway.

CONCLUSION

Our study highlighted a regulatory network consisting of SRF, ANXA2, and NF-κB that was involved in AP progression, possibly providing some novel targets for treating SAP.

Identification of ANXA2 on epithelial cells as a new receptor for secretory IgA using immunoprecipitation and mass spectrometry

Secretory immunoglobulin A plays an important role in the protection against exogenous pathogens and antigens, but it has also been reported to have pathogenic potential. We previously found that secretory immunoglobulin A accumulated in the peripheral lungs during idiopathic pulmonary fibrosis and that transferrin receptor/CD71 was partially involved in secretory immunoglobulin A-induced inflammatory cytokine production in A549 cells. This study aimed to identify the receptor responsible for the induction of cytokine production by secretory immunoglobulin A-stimulated airway epithelial cells. To this end, immunoprecipitation followed by time-of-flight mass spectrometry and peptide mass fingerprinting were performed and Annexin A2 was detected as a novel receptor for secretory immunoglobulin A. Enzyme-linked immunosorbent assay demonstrated binding of secretory immunoglobulin A to Annexin A2, and flow cytometry showed robust expression of Annexin A2 on the surface of BEAS-2B cells, A549 cells, and normal human bronchial/tracheal epithelial cells. Experiments in A549 cells using Annexin A2 small interfering RNA and neutralizing antibodies suggested that Annexin A2 was partially involved in the production of interleukin-8/CXCL8 and C-C motif chemokine ligand 2/monocyte chemoattractant protein-1 induced by secretory immunoglobulin A. Immunohistochemistry using lung sections revealed clear expression of Annexin A2 on airway epithelial cells, although the staining remained equivalent in idiopathic pulmonary fibrosis, asthma, and healthy control lungs. In conclusion, we identified that Annexin A2 expressed in airway epithelial cells is a novel receptor for secretory immunoglobulin A, which is involved in cytokine synthesis.

2D transparent few-layered hydrogen substituted graphdiyne nano-interface for unprecedented ultralow ANXA2 cancer biomarker detection

Herein, we report synthesis of 2D few-layered transparent hydrogen substituted graphdiyne (HsGDY) nanosheets and explored its electrochemical characteristics for the first time to develop a nano-interface for cancer biomarker detection [liver cancer (LC) biomarker; ANXA2]. The semiconducting HsGDY (band gap; 1.98 eV) contains considerable number of sp and sp² hybridised π-electrons with abundant hierarchical pores, thus reveals a negative peripheral charge and high surface area respectively, making it competent to immobilize mass anti-ANXA2 antibodies. The nano-interface platform is fabricated through electrophoretic deposition of HsGDY onto indium tin oxide (ITO) coated glass substrate (50V, 60s) with subsequent immobilization of anti-ANXA2 biomolecules and bovine serum albumin (BSA) to minimize non-specific binding. The pristine HsGDY and fabricated electrodes were characterized using spectroscopic, microscopic, zetasizer, surface area and pore size analyzer as well as electrochemical techniques. The electrochemical response of fabricated HsGDY nano-interface based biosensing platform (BSA/anti-ANXA2/HsGDY/ITO) is investigated via cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques, which covers a wider linear detection range in between 0.01 fg mL^-1 to 1000 ng mL^-1 along with an exceptional sensitivity of 13.8 μA [log (ng mL^-1)]^-1 cm^-2 and 2.8 μA [log (ng mL^-1)]^-1 cm^-2 via CV and DPV techniques, respectively. This developed biosensor has the ability for unprecedented ultralow level i.e., upto 3 molecules of ANXA2 cancer biomarker detection. Moreover, the obtained electrochemical results show excellent correlation with the concentration of ANXA2 cancer biomarker present in LC patients obtained through enzyme linked immunosorbent assay (ELISA) technique.

Recombinantly expressed MeICT, a new toxin from Mesobuthus eupeus scorpion, inhibits glioma cell proliferation and downregulates Annexin A2 and FOXM1 genes

Gliomas are highly invasive and lethal malignancy that do not respond to current therapeutic approaches. Novel therapeutic agents are required to target molecular mechanisms involved in glioma progression. MeICT is a new short-chain toxin isolated from Mesobuthus eupeus scorpion venom. This toxin contained 34 amino acid residues and belongs to chloride channels toxins. In this study, the coding sequence of MeICT was cloned into the pET32Rh vector and a high yield of soluble recombinant MeICT was expressed and purified. Recombinant MeICT-His significantly inhibited the proliferation and migration of glioma cells at low concentration. In vivo studies showed that MeICT was not toxic when administrated to mice at high doses. We also determined the effect of MeICT on the mRNA expression of MMP-2, Annexin A2 and FOXM-2 that are key molecules in the progression and invasion of glioma. Expression of Annexin A2 and FOXM1 mRNA was significantly down-regulated following treatment with MeICT. However, no significant decrease in the expression of MMP-2 gene was identified. In this study a short toxin with four disulfide bonds was successfully produced and its anti-cancer effects was detected. Our findings suggest that recombinant MeICT can be considered as a new potent agent for glioma targeting.

Annexin A2 and Ahnak control cortical NuMA-dynein localization and mitotic spindle orientation

Proper mitotic spindle orientation depends on the correct anchorage of astral microtubules to the cortex. It relies on the remodeling of the cell cortex, a process not fully understood. Annexin A2 (Anx2) is a protein known to be involved in cortical domain remodeling. Here, we report that in early mitosis, Anx2 recruits the scaffold protein Ahnak at the cell cortex facing spindle poles, and the distribution of both proteins is controlled by cell adhesion. Depletion of either protein or impaired cortical Ahnak localization result in delayed anaphase onset and unstable spindle anchoring, which leads to altered spindle orientation. We find that Ahnak is present in a complex with dynein-dynactin. Furthermore, Ahnak and Anx2 are required for dynein and NuMA proper cortical localization and dynamics. We propose that the Ahnak/Anx2 complex influences the cortical organization of the astral microtubule anchoring complex, and thereby mitotic spindle positioning in human cells.

High-fat diet promotes colorectal carcinogenesis through SERCA2 mediated serine phosphorylation of Annexin A2

Colorectal cancer (CRC) is a highly common malignancy, being the third leading cause of cancer death worldwide. Recent epidemiological studies have indicated that carcinogenic effect of diet was mainly attributed to high-fat diets. To investigate the mechanism of high-fat diet-induced colorectal cancer, we systematically quantified the phosphoproteome in human HT-29 cells treated with sodium palmitate (PA). p-Annexin A2 (S26) was predicted to be specifically up-regulated by PA. We confirmed that PA-induced Annexin A2 phosphorylation at Ser26 in C57BL/6 J-Apc^Min/J mice fed with high-fat diet. Phosphorylation of Annexin A2 at Ser26 promotes PA-induced proliferation of HT-29 cells. Moreover, PA suppressed SERCA activity and SERCA2 expression was compensatorily increased. Mechanistically, SERCA2 can partially reverse Annexin A2 phosphorylation at Ser26 caused by PA through intracellular calcium release. Finally, SERCA2 knockdown inhibited high-fat diet-induced tumor growth and Annexin A2 phosphorylation at Ser26 in SCID mice. In all, our studies demonstrate that high-fat diet promotes colorectal carcinogenesis through SERCA2 mediated serine phosphorylation of Annexin A2.

A novel DNA aptamer targeting lung cancer stem cells exerts a therapeutic effect by binding and neutralizing Annexin A2

Cancer remains one of the leading causes of death worldwide. Cancer stem cells (CSCs) are the underlying reason for tumor recurrence, progression, and therapeutic resistance. Aptamers are synthetic single-stranded oligonucleotides that can specifically bind to various molecular targets. Here, we aim to develop an effective aptamer-based biomarker and therapeutic tool that targets CSCs for cancer therapy. We perform whole-cell-based systematic evolution of ligands by exponential enrichment (cell-SELEX) to screen DNA aptamers that specifically bound to lung CSCs, modeled by E-cadherin-silenced A549 cells. We develop a CSC-specific aptamer (AP-9R) specifically recognizing lung CSCs with high affinity and identify Annexin A2, a Ca²⁺-dependent membrane-binding protein, as its target. Annexin A2 expression was upregulated in lung CSCs and involved in cancer stemness. The expression of Annexin A2 was associated with signatures of stemness and metastasis, as well as poor clinical outcomes, in lung cancer in silico. Moreover, AP-9R decreased Annexin A2 expression and suppressed CSC properties in CSCs in vitro and in vivo. The present findings suggest that Annexin A2 is a CSC marker and regulator, and the CSC-specific aptamer AP-9R has potential theranostic applications for lung cancer.

The Ca2+- and phospholipid-binding protein Annexin A2 is able to increase and decrease plasma membrane order

Annexin A2 (AnxA2) is a calcium- and phospholipid-binding protein that plays roles in cellular processes involving membrane and cytoskeleton dynamics and is able to associate to several partner proteins. However, the principal molecular partners of AnxA2 are negatively charged phospholipids such as phosphatidylserine and phosphatidyl-inositol-(4,5)-phosphate. Herein we have studied different aspects of membrane lipid rearrangements induced by AnxA2 membrane binding. X-ray diffraction data revealed that AnxA2 has the property to stabilize lamellar structures and to block the formation of highly curved lipid phases (inverted hexagonal phase, H_II). By using pyrene-labelled cholesterol and the environmental probe di-4-ANEPPDHQ, we observed that in model membranes, AnxA2 is able to modify both, cholesterol distribution and lipid compaction. In epithelial cells, we observed that AnxA2 localizes to membranes of different lipid order. The protein binding to membranes resulted in both, increases and/or decreases in membrane order depending on the cellular membrane regions. Overall, AnxA2 showed the capacity to modulate plasma membrane properties by inducing lipid redistribution that may lead to an increase in order or disorder of the membranes.

Annexin A2 promotes development of retinal neovascularization through PI3K/ AKT signaling pathway

PURPOSE

Retinal Neovascularization (RNV) is a pathological characteristic of ocular diseases. Annexin A2 (ANXA2) plays important roles in RNV while the mechanism remains unclear. The study aimed to explore relationship between ANXA2 and PI3K/AKT signaling pathway in RNV.

METHODS

We used human retinal vascular endothelial cells (HRECs) and oxygen-induced retinopathy (OIR) mice model to show ANXA2 can promote the development of RNV through PI3K/AKT signaling pathway. We divided HRECs into six groups by infecting lentivirus containing appropriate plasmid and adding corresponding solution. Assays showing ability of HRECs were performed in vitro. Mice were randomly divided into three groups and treated accordingly.

RESULTS

Expression of ANXA2 and activity of PI3K/AKT signaling pathway in HRECs were detected. RNV and expression of ANXA2 in mice retinas were detected. Results showed that ANXA2 expression is positively related with RNV-forming ability of HRECs in vitro and development of RNV in vivo while low activity of PI3K/AKT signaling pathway could attenuate the role of ANXA2.

CONCLUSIONS

We can make ANXA2 and PI3K/ AKT signaling pathway as a promising target for the regulation of pathological neovascularization of the retina, which also provides a novel idea for effective prevention and treatment of diseases related to RNV in future.

A monoclonal antibody against annexin A2 targets stem and progenitor cell fractions in tumors

•

Development of a novel antibody (termed as mAb150) developed in our lab which targets annexin A2.

•

Although there are earlier reports of another monoclonal antibody with the same target, the epitope recognized by mAb150 is novel.

•

mAb150 is specifically recognized to target the achilles heel of cancer viz. cancer stem cells and progenitors that persist after treatments and potentially give rise to minimal residual disease.

The involvement of cancer stem cells (CSCs) in driving tumor dormancy and drug resistance is well established. Most therapeutic regimens however are ineffective in targeting these regenerative populations. We report the development and evaluation of a monoclonal antibody, mAb150, which targets the metastasis associated antigen, Annexin A2 (AnxA2) through recognition of a N-terminal epitope. Treatment with mAb150 potentiated re-entry of CSCs into the cell cycle that perturbed tumor dormancy and facilitated targeting of CSCs as was validated by in vitro and in vivo assays. Epigenetic potentiation further improved mAb150 efficacy in achieving total tumor regression by targeting regenerative populations to achieve tumor regression, specifically in high-grade serous ovarian adenocarcinoma.

Molecular Insights on the Possible Role of Annexin A2 in COVID-19 Pathogenesis and Post-Infection Complications

Severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) has infected >235 million people and killed over 4.8 million individuals worldwide. Although vaccines have been developed for prophylactic management, there are no clinically proven antivirals to treat the viral infection. Continuous efforts are being made all over the world to develop effective drugs but these are being delayed by periodic outbreak of mutated SARS-CoV-2 and a lack of knowledge of molecular mechanisms underlying viral pathogenesis and post-infection complications. In this regard, the involvement of Annexin A2 (AnxA2), a lipid-raft related phospholipid-binding protein, in SARS-CoV-2 attachment, internalization, and replication has been discussed. In addition to the evidence from published literature, we have performed in silico docking of viral spike glycoprotein and RNA-dependent RNA polymerase with human AnxA2 to find the molecular interactions. Overall, this review provides the molecular insights into a potential role of AnxA2 in the SARS-CoV-2 pathogenesis and post-infection complications, especially thrombosis, cytokine storm, and insulin resistance.

LncRNA MIR155HG induces M2 macrophage polarization and drug resistance of colorectal cancer cells by regulating ANXA2

OBJECTIVE

To investigate the effects of lncRNA MIR155HG and Annexin A2 (ANXA2) on colorectal cancer (CRC) and the mechanism of the MIR155HG/ANXA2 axis.

METHODS

The expressions of MIR155HG and ANXA2 in human CRC tissues were analyzed for association with pathological characteristics and prognosis of CRC patients. CRC cell lines (Caco2 and HT29) were used to study the effects of MIR155HG or ANXA2 knockdown on tumor cell behaviors and macrophage polarization as well as the effect of M2 polarization on oxaliplatin resistance of CRC cells. RNA immunoprecipitation, RNA pull-down and dual-luciferase reporter assays were applied to verify the targeting relationships among MIR155HG, miR-650 and ANXA2. Heterotopic xenograft models were established to verify the results of cell experiments.

RESULTS

MIR155HG and ANXA2 were highly expressed in CRC tissues/cells and of prognostic values for CRC patients. Knockdown of MIR155HG or ANXA2 suppressed M2 macrophage polarization, and proliferation, migration, invasion and oxaliplatin resistance of CRC cells. MIR155HG competed with ANXA2 for binding miR-650 and can also directly target ANXA2. Knockdown of MIR155HG or ANXA2 also inhibited M2 macrophage polarization and CRC progression in nude mice.

CONCLUSION

This study highlighted that MIR155HG, by regulating the miR-650/ANXA2 axis, promotes CRC progression and enhances oxaliplatin resistance in CRC cells through M2 macrophage polarization.

Circulating annexin A2 as a biomarker in patients with pancreatic cancer

Background

Pancreatic cancer (PC) is a highly lethal malignancy. There are only few predictive or prognostic markers for PC. This study was conducted to investigate the serum levels of annexin A2 (AnxA2) in patients with PC and its relationship with tumor progression and known prognostic parameters.

Materials and Methods

Serum samples were obtained on the first admission before any treatment. Serum AnxA2 levels were determined using enzyme-linked immunosorbent assay. Age- and sex-matched healthy controls were included in the analysis. All statistical tests were carried out using two-sided test, and P ≤ 0.05 was considered statistically significant.

Results

The median age at diagnosis was 59 years. The most common metastatic site was liver in 23 patients with metastasis (n = 19, 83%). At the end of the observation period, thirty-two patients (97%) were dead. Thirty-nine percent of 23 metastatic patients who received palliative chemotherapy (CTx) were CTx responsive. Median overall survival of the whole group was 41.3 ± 8.3 weeks (95% confidence interval = 25-58 weeks). The baseline serum AnxA2 levels were significantly higher in patients with PC than in the control group (P = 0.01). Serum AnxA2 levels were significantly higher in the patients with high erythrocyte sedimentation rate (P = 0.04). Conversely, serum AnxA2 concentration had no prognostic role on survival (P = 0.18).

Conclusions

AnxA2 is identified as a novel secretory biomarker for PC, but it has no role as a prognostic or predictive marker.

(20S) Ginsenoside Rh2 Inhibits STAT3/VEGF Signaling by Targeting Annexin A2

Signal transducers and activators of transcription 3 (STAT3) acts as a transcriptional signal transducer, converting cytokine stimulation into specific gene expression. In tumor cells, aberrant activation of the tyrosine kinase pathway leads to excessive and continuous activation of STAT3, which provides further signals for tumor cell growth and surrounding angiogenesis. In this process, the tumor-associated protein Annexin A2 interacts with STAT3 and promotes Tyr705 phosphorylation and STAT3 transcriptional activation. In this study, we found that (20S) ginsenoside Rh2 (G-Rh2), a natural compound inhibitor of Annexin A2, inhibited STAT3 activity in HepG2 cells. (20S) G-Rh2 interfered with the interaction between Annexin A2 and STAT3, and inhibited Tyr705 phosphorylation and subsequent transcriptional activity. The inhibitory activity of STAT3 leaded to the negative regulation of the four VEGFs, which significantly reduced the enhanced growth and migration ability of HUVECs in co-culture system. In addition, (20S)G-Rh2 failed to inhibit STAT3 activity in cells overexpressing (20S)G-Rh2 binding-deficient Annexin A2-K301A mutant, further proving Annexin A2-mediated inhibition of STAT3 by (20S)G-Rh2. These results indicate that (20S)G-Rh2 is a potent inhibitor of STAT3, predicting the potential activity of (20S)G-Rh2 in targeted therapy applications.

Bufalin induces mitochondrial dysfunction and promotes apoptosis of glioma cells by regulating Annexin A2 and DRP1 protein expression

Background

Glioma is a common primary central nervous system tumour, and therapeutic drugs that can effectively improve the survival rate of patients in the clinic are lacking. Bufalin is effective in treating various tumours, but the mechanism by which it promotes the apoptosis of glioma cells is unclear. The aim of this study was to investigate the drug targets of bufalin in glioma cells and to clarify the apoptotic mechanism.

Methods

Cell viability and proliferation were evaluated by CCK-8 and colony formation assays. Then, the cell cycle and apoptosis, intracellular ion homeostasis, oxidative stress levels and mitochondrial damage were assessed after bufalin treatment. DARTS-PAGE technology was employed and LC–MS/MS was performed to explore the drug targets of bufalin in U251 cells. Molecular docking and western blotting were performed to identify potential targets. siRNA targeting Annexin A2 and the DRP1 protein inhibitor Mdivi-1 were used to confirm the targets of bufalin.

Results

Bufalin upregulated the expression of cytochrome C, cleaved caspase 3, p-Chk1 and p-p53 proteins to induce U251 cell apoptosis and cycle arrest in the S phase. Bufalin also induced oxidative stress in U251 cells, destroyed intracellular ion homeostasis, and caused mitochondrial damage. The expression of mitochondrial division-/fusion-related proteins in U251 cells was abnormal, the Annexin A2 and DRP1 proteins were translocated from the cytoplasm to mitochondria, and the MFN2 protein was released from mitochondria into the cytoplasm after bufalin treatment, disrupting the mitochondrial division/fusion balance in U251 cells.

Conclusions

Our research indicated that bufalin can cause Annexin A2 and DRP1 oligomerization on the surface of mitochondria and disrupt the mitochondrial division/fusion balance to induce U251 cell apoptosis.

Graphic Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02137-x.

Annexin A2 binds the internal ribosomal entry site of c-myc mRNA and regulates its translation

The expression and localization of the oncoprotein c-Myc is highly regulated at the level of transcription, mRNA transport, translation, as well as stability of the protein. We previously showed that Annexin A2 (AnxA2) binds to a specific localization element in the 3'untranslated region (UTR) of c-myc mRNA and is involved in its localization to the perinuclear region. In the present study, we demonstrate that AnxA2 binds in a Ca²⁺-dependent manner to the internal ribosomal entry site (IRES) containing two pseudo-knots in the 5´UTR of the c-myc mRNA. Here, we employ an in vitro rabbit reticulocyte lysate system with chimeric c-myc reporter mRNAs to demonstrate that binding of AnxA2 to the c-myc IRES modulates the expression of c-Myc. Notably, we show that low levels of AnxA2 appear to increase, while high levels of AnxA2 inhibits translation of the chimeric mRNA. However, when both the AnxA2-binding site and the ribosomal docking site in the c-myc IRES are deleted, AnxA2 has no effect on the translation of the reporter mRNA. Forskolin-treatment of PC12 cells results in upregulation of Ser25 phosphorylated AnxA2 expression while c-Myc expression is down-regulated. The effect of forskolin on c-Myc expression and the level of Ser25 phosphorylated AnxA2 was abolished in the presence of EGTA. These findings indicate that AnxA2 regulates both the transport and subsequent translation of the c-myc mRNA, possibly by silencing the mRNA during its transport. They also suggest that AnxA2 act as a switch to turn off the c-myc IRES activity in the presence of calcium.Abbreviations: AnxA2, Annexin A2; β₂--µglob, β₂-microglobulin; cpm, counts per minute; hnRNP, heterogenous nuclear ribonucleoprotein; IRES, internal ribosomal entry site; ITAF, IRES trans-acting factor; MM, multiple myeloma; PABP, poly(A)-binding protein; PCBP, poly(rC) binding protein; PSF, PTB-associated splicing factor; PTB, polypyrimidine tract binding protein; RRL, rabbit reticulocyte lysate; UTR, untranslated region; YB, Y-box binding protein.

Recombinant Annexin A2 Administration Improves Neurological Outcomes After Traumatic Brain Injury in Mice

Microvascular failure is one of the key pathogenic factors in the dynamic pathological evolution after traumatic brain injury (TBI). Our laboratory and others previously reported that Annexin A2 functions in blood-brain barrier (BBB) development and cerebral angiogenesis, and recombinant human Annexin A2 (rA2) protected against hypoxia plus IL-1β-induced cerebral trans-endothelial permeability in vitro, and cerebral angiogenesis impairment of AXNA2 knock-out mice in vivo. We thereby hypothesized that ANXA2 might be a cerebrovascular therapy candidate that targets early BBB integrity disruption, and subacute/delayed cerebrovascular remodeling after TBI, ultimately improve neurological outcomes. In a controlled cortex impact (CCI) mice model, we found rA2 treatment (1 mg/kg) significantly reduced early BBB disruption at 24 h after TBI; and rA2 daily treatment for 7 days augmented TBI-induced mRNA levels of pro-angiogenic and endothelial-derived trophic factors in cerebral microvessels. In cultured human brain microvascular endothelial cells (HBMEC), through MAPKs array, we identified that rA2 significantly activated Akt, ERK, and CREB, and the activated CREB might be responsible for the rA2-induced VEGF and BDNF expression. Moreover, rA2 administration significantly increased cerebral angiogenesis examined at 14 days and vessel density at 28 days after TBI in mice. Consistently, our results validated that rA2 significantly induced angiogenesis in vitro, evidenced by tube formation and scratched migration assays in HBMEC. Lastly, we demonstrated that rA2 improved long-term sensorimotor and cognitive function, and reduced brain tissue loss at 28 days after TBI. Our findings suggest that rA2 might be a novel vascular targeting approach for treating TBI.

LINC01133 promotes hepatocellular carcinoma progression by sponging miR-199a-5p and activating annexin A2

BACKGROUND

Long noncoding RNAs (lncRNAs) are functionally associated with cancer development and progression. Although gene copy number variation (CNV) is common in hepatocellular carcinoma (HCC), it is not known how CNV in lncRNAs affects HCC progression and recurrence. We aimed to identify a CNV-related lncRNA involved in HCC progression and recurrence and illustrate its underlying mechanisms and prognostic value.

METHODS

We analyzed the whole genome sequencing (WGS) data of matched cancerous and noncancerous liver samples from 49 patients with HCC to identify lncRNAs with CNV. The results were validated in another cohort of 238 paired HCC and nontumor samples by TaqMan copy number assay. We preformed Kaplan-Meier analysis and log-rank test to identify lncRNA CNV with prognostic value. We conducted loss- and gain-of-function studies to explore the biological functions of LINC01133 in vitro and in vivo. The competing endogenous RNAs (ceRNAs) mechanism was clarified by microRNA sequencing (miR-seq), quantitative real-time PCR (qRT-PCR), western blot, and dual-luciferase reporter assays. We confirmed the binding mechanism between lncRNA and protein by RNA pull-down, RNA immunoprecipitation, qRT-PCR, and western blot analyses.

RESULTS

Genomic copy numbers of LINC01133 were increased in HCC, which were positively related with the elevated expression of LINC01133. Increased copy number of LINC01133 predicted the poor prognosis in HCC patients. LINC01133 overexpression in HCC cells promoted proliferation and aggressive phenotypes in vitro, and facilitated tumor growth and lung metastasis in vivo, whereas LINC01133 knockdown had the opposite effects. LINC01133 sponged miR-199a-5p, resulting in enhanced expression of SNAI1, which induced epithelial-to-mesenchymal transition (EMT) in HCC cells. In addition, LINC01133 interacted with Annexin A2 (ANXA2) to activate the ANXA2/STAT3 signaling pathway.

CONCLUSIONS

LINC01133 promotes HCC progression by sponging miR-199a-5p and interacting with ANXA2. LINC01133 CNV gain is predictive of poor prognosis in patients with HCC.

Human colorectal cancer-associated carbohydrate antigen on annexin A2 protein

Cancer-associated antigens are not only a good marker for monitoring cancer progression but are also useful for molecular target therapy. In this study, we aimed to generate a monoclonal antibody that preferentially reacts with colorectal cancer cells relative to noncancerous gland cells. We prepared antigens composed of HT-29 colorectal cancer cell lysates that were adsorbed by antibodies to sodium butyrate-induced enterocytically differentiated HT-29 cells. Subsequently, we generated a monoclonal antibody, designated 12G5A, which reacted with HT-29 colon cancer cells, but not with sodium butyrate-induced differentiated HT-29 cells. Immunohistochemical staining revealed 12G5A immunoreactivity in all 73 colon cancer tissue specimens examined at various degrees, but little or no immunoreactivity in noncancerous gland cells. Notably, high 12G5A immunoreactivity, which was determined as more than 50% of colon cancer cells intensively stained with 12G5A antibody, exhibited significantly higher association with a poor overall survival rate of patients with colorectal cancer (P = 0.0196) and unfavorable progression-free survival rate of patients with colorectal cancer (P = 0.0418). Matrix-assisted laser desorption ionization time-of-flight mass spectrometry, si-RNA silencing analysis, enzymatic deglycosylation, and tunicamycin treatment revealed that 12G5A recognized the glycosylated epitope on annexin A2 protein. Our findings indicate that 12G5A identified a cancer-associated glycosylation epitope on annexin A2, whose expression was related to unfavorable colorectal cancer behavior. KEY MESSAGE: • 12G5A monoclonal antibody recognized a colorectal cancer-associated epitope. • 12G5A antibody recognized the N-linked glycosylation epitope on annexin A2. • 12G5A immunoreactivity was related to unfavorable colorectal cancer behavior.

Advances in cancer treatment: a new therapeutic target, Annexin A2

Annexin A2 (ANXA2) is a calcium regulated phospholipid-binding protein. It is expressed in some tumor cells, endothelial cells, macrophages, and mononuclear cells, affecting cell survival and mediating interactions between intercellular and extracellular microenvironment. Aberrant expression of ANXA2 can be used as a potential predictive factor, diagnostic biomarker and therapeutic target in cancer therapy. Investigators used various technologies to target ANXA2 in a preclinical model of human cancers and demonstrated encouraging results. In this review article, we discuss the diagnosis and prognosis latent capacity of ANXA2 in progressive cancers, focus on the exploration of restorative interventions targeting ANXA2 in cancer treatment. Further, we comment on a promising candidate therapy that is conceivable for clinical translation.

Decreased expression of annexin A2 and loss of its association with vascular endothelial growth factor leads to the deficient trophoblastic invasion in preeclampsia

OBJECTIVES

Preeclampsia (PE) remains the major cause for maternal and foetal mortality and morbidity. Invasion of endovascular trophoblast and remodelling of spiral artery are crucial actions of normal placental development. Non-fulfilment of these processes plays a leading role in the development of preeclampsia. Vascular endothelial growth factor (VEGF) is produced by extravillous trophoblastic tissue and decidual cell population is a well-known angiogenic growth which plays a fundamental role in placental pathogenesis of PE. Annexin A2 (ANXA2) is a profibrinolytic protein receptor required for plasminolysis, which is an important step in the formation of new blood vessel along with VEGF. Role of ANXA2 is poorly studied in context with human reproductive disease like preeclampsia. The purpose of the present study is to examine the expression and association of VEGF and ANXA2 in the term placentas of pregnancies with and without PE.

METHODS

The study group comprised of placental tissues procured from gestations with PE (n=30) and without (n=20) PE. The expression of VEGF and ANXA2 in the placental villous tissue was evaluated quantitatively by means of IHC, western blotting and reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS

Our IHC, western blotting and RT-PCR analysis illustrated the significant decrease in the expression of VEGF and ANXA2 in PE group compared with the normotensive control group (p<0.005). We observed statistically significant positive correlation among the expression of ANXA2 and VEGF in placentas of normotensive control group (p<0.0001).

CONCLUSIONS

The diminished expression of VEGF and ANXA2 in placenta may be associated with the defective angiogenesis and which may possibly play a vital role in PE pathogenesis.

aeruginosa infection

Pseudomonas aeruginosa is a severe Gram-negative opportunistic bacterium that causes a spectrum of organ system diseases, particularly in immunocompromised patients. This bacterium has been shown to induce unfolded protein response (UPR) during mammalian infection. Annexin A2 (AnxA2) is a multicompartmental protein relating to a number of cellular processes; however, it remains unknown whether AnxA2 coordinates a UPR pathway under bacterial infection conditions. Here, we report that the endoplasmic reticulum stress inositol-requiring enzyme 1 (IRE1)-X-box binding protein 1 (XBP1) pathway was up-regulated by AnxA2 through p38 MAPK signaling following P. aeruginosa infection in macrophages, whereas ATF4 and ATF6 not. In addition, XBP1 was found as a positive regulator of innate immunity to tame P. aeruginosa challenges by enhancing autophagy and bacterial clearance. XBP1 also facilitated NF-κB activation to elicit the release of proinflammatory cytokines predominantly in macrophages. Together, our findings identify AnxA2 as a regulator for XBP1-mediated UPR pathway.

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.

Altered Serum Annexin A2 Might Be a New Potential Diagnostic Biomarker in Human Colorectal Cancer

OBJECTIVE

Annexin A2 is a calcium dependent phospholipid binding protein that is a biomarker in cancers. However, the value of serum Annexin A2 in the diagnosis of colorectal cancer (CRC) is not clear. This study aimed to investigate clinical utility of serum Annexin A2 as a potential biomarker for CRC.

METHODS

Annexin A2 was analyzed in 20 cases of CRC tissues and 20 controls of normal adjacent paired tissues. Serum Annexin A2 was calculated in 59 CRC patients and 44 healthy subjects. Receiver operating characteristic (ROC) curve and logistic regression were utilized to evaluate the diagnostic effectiveness and construct diagnostic model.

RESULTS

Annexin A2 in CRC tissues was slightly higher than in normal adjacent paired tissues (χ2=6.0652, p<0.05). Serum Annexin A2 in CRC patients was significantly lower than in healthy controls (p<0.05). Besides, the levels of serum Annexin A2 were lower in patients with poor tumor differentiation than in well or moderate tumor differentiation (p=0.0111). ROC analysis indicated the diagnostic efficacy of serum Annexin A2 was better than carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA199) for CRC. Furthermore, joint detection of Annexin A2 and CEA had the maximum area under the ROC curve (AUC) in discriminating CRC from healthy controls (AUC 0.931, sensitivity 86.4%, specificity 84.7%, positive predictive value 87.9%, and negative predictive value 82.2%).

CONCLUSIONS

Serum Annexin A2 may be a non-invasive and promising biomarker for the diagnosis of CRC, and the joint detection of Annexin A2 and CEA may have been favorable clinical applied value in the diagnosis of CRC.