Annexin A1 in primary tumors promotes melanoma dissemination

Transglutaminase Type 2-MITF axis regulates phenotype switching in skin cutaneous melanoma

Skin cutaneous melanoma (SKCM) is the deadliest form of skin cancer due to its high heterogeneity that drives tumor aggressiveness. Melanoma plasticity consists of two distinct phenotypic states that co-exist in the tumor niche, the proliferative and the invasive, respectively associated with a high and low expression of MITF, the master regulator of melanocyte lineage. However, despite efforts, melanoma research is still far from exhaustively dissecting this phenomenon. Here, we discovered a key function of Transglutaminase Type-2 (TG2) in regulating melanogenesis by modulating MITF transcription factor expression and its transcriptional activity. Importantly, we demonstrated that TG2 expression affects melanoma invasiveness, highlighting its positive value in SKCM. These results suggest that TG2 may have implications in the regulation of the phenotype switching by promoting melanoma differentiation and impairing its metastatic potential. Our findings offer potential perspectives to unravel melanoma vulnerabilities via tuning intra-tumor heterogeneity.

ANXA1 Promotes Tumor Immune Evasion by Binding PARP1 and Upregulating Stat3-Induced Expression of PD-L1 in Multiple Cancers

The deregulation of Annexin A1 (ANXA1), a regulator of inflammation and immunity, leads to cancer growth and metastasis. However, whether ANXA1 is involved in cancer immunosuppression is still unclear. Here, we report that ANXA1 knockdown (i) dramatically downregulates programmed cell death-ligand 1 (PD-L1) expression in breast cancer, lung cancer, and melanoma cells; (ii) promotes T cell-mediated killing of cancer cells in vitro; and (iii) inhibits cancer immune escape in immune-competent mice via downregulating PD-L1 expression and increasing the number and killing activity of CD8+ T cells. Mechanistically, ANXA1 functioned as a sponge molecule for interaction of PARP1 and Stat3. Specifically, binding of ANXA1 to PARP1 decreased PARP1's binding to Stat3, which reduced poly(ADP-ribosyl)ation and dephosphorylation of Stat3 and thus, increased Stat3's transcriptional activity, leading to transcriptionally upregulated expression of PD-L1 in multiple cancer cells. In clinical samples, expression of ANXA1 and PD-L1 was significantly higher in breast cancer, non-small cell lung cancer, and skin cutaneous melanoma compared with corresponding normal tissues and positively correlated in cancer tissues. Moreover, using both ANXA1 and PD-L1 proteins for predicting efficacy of anti-PD-1 immunotherapy and patient prognosis was superior to using individual proteins. Our data suggest that ANXA1 promotes cancer immune escape via binding PARP1 and upregulating Stat3-induced expression of PD-L1, that ANXA1 is a potential new target for cancer immunotherapy, and combination of ANXA1 and PD-L1 expression is a potential marker for predicting efficacy of anti-PD-1 immunotherapy in multiple cancers.

Annexin A12-26 hydrogel improves healing properties in an experimental skin lesion after induction of type 1 diabetes

Diabetes mellitus (DM) is characterized by metabolic alterations that involve defects in the secretion and/or action of insulin, being responsible for several complications, such as impaired healing. Studies from our research group have shown that annexin A1 protein (AnxA1) is involved in the regulation of inflammation and cell proliferation. In light of these findings, we have developed a new technology and evaluated its effect on a wound healing in vivo model using type 1 diabetes (T1DM)-induced mice. We formulated a hydrogel containing AnxA12-26 using defined parameters such as organoleptic characteristics, pH, UV-vis spectroscopy and cytotoxicity assay. UV-vis spectroscopy confirmed the presence of the associated AnxA12-26 peptide in the three-dimensional hydrogel matrix, while the in vitro cytotoxicity assay showed excellent biocompatibility. Mice showed increased blood glucose levels, confirming the efficacy of streptozotocin (STZ) to induce T1DM. Treatment with AnxA12-26 hydrogel showed to improve diabetic wound healing, defined as complete re-epithelialization and tissue remodeling, with reduction of inflammatory infiltrate in diabetic animals. We envisage that the AnxA12-26 hydrogel, with its innovative composition and formulation be efficient on improving diabetic healing and contributing on the expansion of the therapeutic arsenal to treat diabetic wounds, at a viable cost.

Targeting of Annexin A1 in Tumor-associated Macrophages as a therapeutic strategy for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a common aggressive, malignant tumor with limited treatment options. Currently, immunotherapies have low success rates in the treatment of HCC. Annexin A1 (ANXA1) is a protein related to inflammation, immunity and tumorigenesis. However, the role of ANXA1 in liver tumorigenesis remains unknown. Therefore, we sought to explore the feasibility of ANXA1 as a therapeutic target for HCC. Here, we analyzed ANXA1 expression and localization by HCC microarray and immunofluorescence experiments. Using an in vitro culture system, monocytic cell lines and primary macrophages were employed to investigate the biological functions of cocultured HCC cells and cocultured T cells. In vivo, Ac2-26, human recombinant ANXA1 (hrANXA1), and cell depletion (macrophages or CD8 + T cells) experiments were further conducted to investigate the role of ANXA1 in the tumor microenvironment (TME). We found that ANXA1 was overexpressed in mesenchymal cells, especially macrophages, in human liver cancer. Moreover, the expression of ANXA1 in mesenchymal cells was positively correlated with programmed death-ligand 1 expression. Knockdown of ANXA1 expression inhibited HCC cell proliferation and migration by increasing the M1/M2 macrophage ratio and promoting T-cell activation. hrANXA1 promoted malignant growth and metastasis in mice by increasing the infiltration and M2 polarization of tumor-associated macrophages (TAMs), generating an immunosuppressive TME and suppressing the antitumor CD8 + T-cell response. Together, our findings reveal that ANXA1 may be an independent prognostic factor for HCC and demonstrate the clinical translational significance of ANXA1 for tumor immunotherapy in HCC.

Similarities and Differences in the Protein Composition of Cutaneous Melanoma Cells and Their Exosomes Identified by Mass Spectrometry

Intercellular transport of proteins mediated by extracellular vesicles (EVs)-exosomes and ectosomes-is one of the factors facilitating carcinogenesis. Therefore, the research on protein cargo of melanoma-derived EVs may provide a better understanding of the mechanisms involved in melanoma progression and contribute to the development of alternative biomarkers. Proteomic data on melanoma-derived EVs are very limited. The shotgun nanoLC-MS/MS approach was applied to analyze the protein composition of primary (WM115, WM793) and metastatic (WM266-4, WM1205Lu) cutaneous melanoma cells and exosomes released by them. All cells secreted homogeneous populations of exosomes that shared a characteristic set of proteins. In total, 3514 and 1234 unique proteins were identified in melanoma cells and exosomes, respectively. Gene ontology analysis showed enrichment in several cancer-related categories, including cell proliferation, migration, negative regulation of apoptosis, and angiogenesis. The obtained results broaden our knowledge on the role of selected proteins in exosome biology, as well as their functional role in the development and progression of cutaneous melanoma. The results may also inspire future studies on the clinical potential of exosomes.

Role of Annexin A1 Secreted by Neutrophils in Melanoma Metastasis

Annexin A1 (AnxA1) is highly secreted by neutrophils and binds to formyl peptide receptors (FPRs) to trigger anti-inflammatory effects and efferocytosis. AnxA1 is also expressed in the tumor microenvironment, being mainly attributed to cancer cells. As recruited neutrophils are player cells at the tumor sites, the role of neutrophil-derived AnxA1 in lung melanoma metastasis was investigated here. Melanoma cells and neutrophils expressing AnxA1 were detected in biopsies from primary melanoma patients, which also presented higher levels of serum AnxA1 and augmented neutrophil-lymphocyte ratio (NLR) in the blood. Lung melanoma metastatic mice (C57BL/6; i.v. injected B16F10 cells) showed neutrophilia, elevated AnxA1 serum levels, and higher labeling for AnxA1 in neutrophils than in tumor cells at the lungs with metastasis. Peritoneal neutrophils collected from naïve mice were co-cultured with B16F10 cells or employed to obtain neutrophil-conditioned medium (NCM; 18 h incubation). B16F10 cells co-cultured with neutrophils or with NCM presented higher invasion, which was abolished if B16F10 cells were previously incubated with FPR antagonists or co-cultured with AnxA1 knockout (AnxA1^-/-) neutrophils. The depletion of peripheral neutrophils during lung melanoma metastasis development (anti-Gr1; i.p. every 48 h for 21 days) reduced the number of metastases and AnxA1 serum levels in mice. Our findings show that AnxA1 secreted by neutrophils favors melanoma metastasis evolution via FPR pathways, addressing AnxA1 as a potential biomarker for the detection or progression of melanoma.

Urinary protein biomarker panel predicts esophageal squamous carcinoma from control cases and other tumors

PURPOSE

Discovery of noninvasive urinary biomarkers for the early diagnosis of esophageal squamous carcinoma (ESCC).

METHODS

We conducted proteomic analyses of 499 human urine samples obtained from healthy individuals (n = 321) and ESCC (n = 83), bladder cancer (n = 17), breast cancer (n = 12), colorectal cancer (n = 16), lung cancer (n = 33) and thyroid cancer (n = 17) patients from multiple medical centers. Those samples were divided into a discovery set (n = 247) and an independent validation set (n = 157).

RESULTS

Among urinary proteins identified in the comprehensive quantitative proteomics analysis, we selected a panel of three urinary biomarkers (ANXA1, S100A8, TMEM256), and established a logistic regression model in the discovery set that can correctly classify the majority of ESCC cases in the validation sets with the area under the curve (AUC) values of 0.825. This urinary biomarker panel not only discriminates ESCC patients from healthy individuals but also differentiates ESCC from other common tumors. Notably, the panel distinguishes stage I ESCC patients from healthy individuals with AUC values of 0.886. On the analysis of stage-specific biomarkers, another combination panel of protein (ANXA1, S100A8, SOD3, TMEM256) demonstrated a good AUC value of 0.792 for stage I ESCC.

CONCLUSIONS

Urinary biomarker panel represents a promising auxiliary diagnostic tool for ESCC, including early-stage ESCC.

Overexpression of Annexin A1 is associated with the formation of capillaries in infantile hemangioma

Infantile hemangioma is a common benign tumor in infants. However, the molecular mechanism that controls the proliferation and differentiation of hemangioma is not well understood. Annexin A1 (ANX A1) is a phospholipid-binding protein involved in a variety of biological processes, including inflammation, cell proliferation and apoptosis. To explore the significance of ANX A1 in the process of proliferation or differentiation of hemangioma, proliferating and involuting hemangioma tissues were collected to detect the expression of ANX A1 using immunohistochemistry and western blotting. Normal skin tissues were used as the negative control. The results revealed that ANX A1 was upregulated in the proliferative phase of hemangioma, and its expression was decreased when the hemangioma entered the involuting phase. Additionally, in the proliferative phase, the strongest staining of ANX A1 was observed in newly born capillaries, and the staining of ANX A1 became weaker in enlarged vessels, indicating that ANX A1 plays an important role in promoting the formation of capillaries. The expression of hypoxia-inducible factor (HIF)-1α was positively associated with the expression trend of ANX A1, suggesting that the overexpression of ANX A1 may be associated with the increase of HIF-1α. In summary, the results of the present study revealed that the expression of ANX A1 was increased in proliferating hemangioma tissue, and that high expression of ANX A1 may be closely associated with the formation of capillaries in infantile hemangioma.

Annexin A1 promotes the progression of bladder cancer via regulating EGFR signaling pathway

BACKGROUND

Bladder cancer (BLCA) is one of the most common malignancies worldwide. One of the main reasons for the unsatisfactory management of BLCA is the complex molecular biological mechanism. Annexin A1 (ANXA1), a Ca²⁺-regulated phospholipid-binding protein, has been demonstrated to be implicated in the progression and prognosis of many cancers. However, the expression pattern, biological function and mechanism of ANXA1 in BLCA remain unclear.

METHODS

The clinical relevance of ANXA1 in BLCA was investigated by bioinformatics analysis based on TCGA and GEO datasets. Immunohistochemical (IHC) analysis was performed to detect the expression of ANXA1 in BLCA tissues, and the relationships between ANXA1 and clinical parameters were analyzed. In vitro and in vivo experiments were conducted to study the biological functions of ANXA1 in BLCA. Finally, the potential mechanism of ANXA1 in BLCA was explored by bioinformatics analysis and verified by in vitro and in vivo experiments.

RESULTS

Bioinformatics and IHC analyses indicated that a high expression level of ANXA1 was strongly associated with the progression and poor prognosis of patients with BLCA. Functional studies demonstrated that ANXA1 silencing inhibited the proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) of BLCA cells in vitro, and suppressed the growth of xenografted bladder tumors in vivo. Mechanistically, loss of ANXA1 decreased the expression and phosphorylation level of EGFR and the activation of downstream signaling pathways. In addition, knockdown of ANXA1 accelerated ubiquitination and degradation of P-EGFR to downregulate the activation of EGFR signaling.

CONCLUSIONS

These findings indicate that ANXA1 is a reliable clinical predictor for the prognosis of BLCA and promotes proliferation and migration by activating EGFR signaling in BLCA. Therefore, ANXA1 may be a promising biomarker for the prognosis of patients with BLCA, thus shedding light on precise and personalized therapy for BLCA in the future.

Annexin A1 as a Regulator of Immune Response in Cancer

Annexin A1 is a 37 kDa phospholipid-binding protein that is expressed in many tissues and cell types, including leukocytes, lymphocytes and epithelial cells. Although Annexin A1 has been extensively studied for its anti-inflammatory activity, it has been shown that, in the cancer context, its activity switches from anti-inflammatory to pro-inflammatory. Remarkably, Annexin A1 shows pro-invasive and pro-tumoral properties in several cancers either by eliciting autocrine signaling in cancer cells or by inducing a favorable tumor microenvironment. Indeed, the signaling of the N-terminal peptide of AnxA1 has been described to promote the switching of macrophages to the pro-tumoral M2 phenotype. Moreover, AnxA1 has been described to prevent the induction of antigen-specific cytotoxic T cell response and to play an essential role in the induction of regulatory T lymphocytes. In this way, Annexin A1 inhibits the anti-tumor immunity and supports the formation of an immunosuppressed tumor microenvironment that promotes tumor growth and metastasis. For these reasons, in this review we aim to describe the role of Annexin A1 in the establishment of the tumor microenvironment, focusing on the immunosuppressive and immunomodulatory activities of Annexin A1 and on its interaction with the epidermal growth factor receptor.

The Association of Annexin A1 and Chemosensitivity to Osimertinib in Lung Cancer Cells

Simple Summary

Annexin A1 (ANXA1) is associated with the growth and resistance to chemotherapy drugs in lung cancer cells. In this study, the association of ANXA1 with chemosensitivity to Osimertinib, a third generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) was studied. The knockdown of ANXA1 increased chemosensitivity to Osimertinib and decreased tumorigenesis, invasion and migration of lung cancer cells with EGFR mutations. The study showed that ANXA1 plays critical roles in chemosensitivity to Osimertinib in lung cancer cells with EGFR mutations.

Abstract

Annexin A1 (ANXA1) has been reported to promote tumor growth and resistance to chemotherapy drugs in lung cancer cells. In this study, we focused on the association of ANXA1 and chemosensitivity with a third generation epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI), Osimertinib, in lung cancer cells with EGFR mutations. The overexpression of ANXA1 was observed in the lung cancer cells studied. The downregulation of ANXA1 with small interference RNA (siRNA) decreased the growth of lung cancer cells. In lung cancer cells with EGFR mutations, the knockdown of ANXA1 increased the chemosensitivity to Osimertinib, and decreased the tumorigenesis, invasion and migration of lung cancer cells. Further study showed that the knockdown of ANXA1 inhibited the phosphorylation of EGFR and down-stream Akt pathways and promoted apoptosis in lung cancer cells treated with Osimertinib. A mice xenograft lung cancer model was established in our study and showed that ANXA1 siRNA enhanced the effects of Osimertinib in vivo. Our study results showed that ANXA1 plays critical roles in chemosensitivity to EGFR-TKI in lung cancer cells with the EGFR mutation. Our efforts may be used in the development of lung cancer treatment strategies in the future.

Characterization of Tumor-Associated Macrophages and the Immune Microenvironment in Limited-Stage Neuroendocrine-High and -Low Small Cell Lung Cancer

Simple Summary

To date, the therapeutic strategy and guidelines in small cell lung cancer (SCLC) are based on cancer cell-related attributes with no biomarker used in the clinical practice. In the present study, using RNAseq and IHC, we aim to characterize in the frontline the latest biomarkers of tumor-associated macrophages (TAMs), myeloid-derived suppressor cells (MDSC) and related critical elements, regulating the anti-tumor immune response. Accordingly, we extensively evaluated the TME associations in primary tumors and matched lymph node metastases in different tumor compartments (stroma and tumor nests) and neuroendocrine (NE) subtypes in limited-stage SCLC. We show the RNA gene enrichment of the most critical molecular pathways based on the Gene Ontology (GO) iteration system using thorough bioinformatics analysis to identify new molecular targets in distinct NE subtypes.

Abstract

This study aims to characterize tumor-infiltrating macrophages (TAMs), myeloid-derived suppressor cells (MDSC), and the related molecular milieu regulating anti-tumor immunity in limited-stage neuroendocrine (NE)-high and NE-low small cell lung cancer. Primary tumors and matched lymph node (LN) metastases of 32 resected, early-stage SCLC patients were analyzed by immunohistochemistry (IHC) with antibodies against pan-macrophage marker CD68, M2-macrophage marker CD163, and MDSC marker CD33. Area-adjusted cell counting on TMAs showed that TAMs are the most abundant cell type in the TME, and their number in tumor nests exceeds the number of CD3 + T-cells (64% vs. 38% in NE-low and 71% vs. 18% in NE-high). Furthermore, the ratio of CD163-expressing M2-polarized TAMs in tumor nests was significantly higher in NE-low vs. NE-high tumors (70% vs. 31%). TAM density shows a strong positive correlation with CD45 and CD3 in tumor nests, but not in the stroma. fGSEA analysis on a targeted RNAseq oncological panel of 2560 genes showed that NE-high tumors exhibited increased enrichment in pathways related to cell proliferation, whereas in NE-low tumors, immune response pathways were significantly upregulated. Interestingly, we identified a subset of NE-high tumors representing an immune-oasis phenotype, but with a different gene expression profile compared to NE-low tumors. In contrast, we found that a limited subgroup of NE-low tumors is immune-deserted and express distinct cellular pathways from NE-high tumors. Furthermore, we identified potential molecular targets based on our expression data in NE-low and immune-oasis tumor subsets, including CD70, ANXA1, ITGB6, TP63, IFI27, YBX3 and CXCR2.

Role of Annexin A1 in Squamous Cell Lung Cancer Progression

Lung cancer remains the primary cause of cancer-related death worldwide, and its molecular mechanisms of tumor progression need further characterization to improve the clinical management of affected patients. The role of Annexin A1 (ANXA1) in tumorigenesis and cancer progression in general and especially in lung cancer remains to be controversial and seems to be highly tissue specific and inconsistent among tumor initiation, progression, and metastasis. In the current study, we investigated ANXA1 expression in 81 squamous cell lung cancer (SQCLC), 86 pulmonary adenocarcinoma (AC), and 30 small cell lung cancer (SCLC) patient-derived tissue samples and its prognostic impact on patient's survival. Mechanistically, we analyzed the impact of ANXA1 expression on proliferation and migration of SQCLC cell lines using CRISPR-Cas9 and mammalian overexpression vectors. Strong expression of ANXA1 was significantly correlated to longer overall survival only in SQCLC patients (P = 0.019). Overexpression of ANXA1 promoted proliferation in SQCLC cell lines but suppressed their migration, while knockout of ANXA1 promoted cell migration and suppressed proliferation. In conclusion, ANXA1 expression might elongate patients' survival by inhibiting tumor cell migration and subsequent metastasis.

ANXA1 enhances tumor proliferation and migration by regulating epithelial-mesenchymal transition and IL-6/JAK2/STAT3 pathway in papillary thyroid carcinoma

Background: Annexin A1 (ANXA1) was discovered to show various effects during tumor initiation and development in a tumor-specific manner. However, the function of ANXA1 in papillary thyroid carcinoma (PTC) has not been reported. Methods: Bioinformatic analyses, RT-PCR and immunohistochemistry were employed to determine the ANXA1 expression level in PTC. Both gain- and loss-of-function studies, including CCK-8, EdU assay, transwell experiment and wound-healing assay were used to investigate the role of ANXA1 in PTC progression. GSEA enrichment analysis was utilized to explore the potential mechanisms of ANXA1 mediated downstream signaling, and ELISA, RT-PCR and western blot were used to confirm the relevance. Results: ANXA1 expression was prominently upregulated in PTC tumor tissues. Ectopic expression of ANXA1 expedited PTC cell proliferation, migration and invasion, whereas ANXA1 knockdown exhibited the opposing trends. Mechanistic investigations showed that ANXA1 regulated epithelial-mesenchymal transition (EMT) and activated the IL-6/JAK2/STAT3 pathway to contribute to PTC malignant behaviors. In particular, loss of ANXA1 retarded tumor burden and suppressed lung metastasis in vivo. Conclusions: In conclusion, our findings identified ANXA1 as a pivotal oncogene during PTC carcinogenesis and ANXA1 might function as a promising therapeutic target and prognostic marker for PTC.

MITF functions as a tumor suppressor in non-small cell lung cancer beyond the canonically oncogenic role

Microphthalamia-associated transcription factor (MITF) is a critical mediator in melanocyte differentiation and exerts oncogenic functions in melanoma progression. However, the role of MITF in non-small cell lung cancer (NSCLC) is still unknown. We found that MITF is dominantly expressed in the low-invasive CL1-0 lung adenocarcinoma cells and paired adjacent normal lung tissues. MITF expression is significantly associated with better overall survival and disease-free survival in NSCLC and serves as an independent prognostic marker. Silencing MITF promotes tumor cell migration, invasion and colony formation in lung adenocarcinoma cells. In xenograft mouse model, MITF knockdown enhances metastasis and tumorigenesis, but decreases angiogenesis in the Matrigel plug assay. Whole transcriptome profiling of the landscape of MITF regulation in lung adenocarcinoma indicates that MITF is involved in cell development, cell cycle, inflammation and WNT signaling pathways. Chromatin immunoprecipitation assays revealed that MITF targets the promoters of FZD7, PTGR1 and ANXA1. Moreover, silencing FZD7 reduces the invasiveness that is promoted by silencing MITF. Strikingly, MITF has significantly inverse correlations with the expression of its downstream genes in lung adenocarcinoma. In summary, we demonstrate the suppressive role of MITF in lung cancer progression, which is opposite to the canonical oncogenic function of MITF in melanoma.

Annexin A1: A Bane or a Boon in Cancer? A Systematic Review

Annexin A1 has been extensively investigated as an anti-inflammatory protein, but its role in different types of cancer has not been consolidated in a single systematic review to date. Thus, the aim of this paper is to systematically review and critically analyse 18 studies (in-vivo and in-vitro) to consolidate, in a concerted manner, all the information on differential expression of Annexin A1 in different types of cancer and the role this protein plays in tumorigenesis. Pubmed, Scopus, Web of Science, and ScienceDirect were used for the literature search and the keywords used are “annexin A1,” “lipocortin 1,” “cancer,” “malignancy,” “neoplasm,” “neoplasia,” and “tumor.” A total of 1128 articles were retrieved by implementing a standard search strategy subjected to meticulous screening processes and 442 articles were selected for full article screening. A total of 18 articles that adhered to the inclusion criteria were included in the systematic review and these articles possessed low to moderate bias. These studies showed a strong correlation between Annexin A1 expression and cancer progression via modulation of various cancer-associated pathways. Differential expression of Annexin A1 is shown to play a role in cellular proliferation, metastasis, lymphatic invasion, and development of resistance to anti-cancer treatment. Meta-analysis in the future may provide a statistically driven association between Annexin A1 expression and malignancy progression.

Doxorubicin-Conjugated Innovative 16-mer DNA Aptamer-Based Annexin A1 Targeted Anti-Cancer Drug Delivery

Aptamers are small, functional single-stranded DNA or RNA oligonucleotides that bind to their targets with high affinity and specificity. Experimentally, aptamers are selected by the systematic evolution of ligands by exponential enrichment (SELEX) method. Here, we have used rational drug designing and bioinformatics methods to design the aptamers, which involves three different steps. First, finding a probable aptamer-binding site, and second, designing the recognition and structural parts of the aptamers by generating a virtual library of sequences, selection of specific sequence via molecular docking, molecular dynamics (MD) simulation, binding energy calculations, and finally evaluating the experimental affinity. Following this strategy, a 16-mer DNA aptamer was designed for Annexin A1 (ANXA1). In a direct binding assay, DNA1 aptamer bound to the ANXA1 with dissociation constants value of 83 nM. Flow cytometry and fluorescence microscopy results also showed that DNA1 aptamer binds specifically to A549, HepG2, U-87 MG cancer cells that overexpress ANXA1 protein, but not to MCF7 and L-02, which are ANXA1 negative cells. We further developed a novel system by conjugating DNA1 aptamer with doxorubicin and its efficacy was studied by cellular uptake and cell viability assay. Also, anti-tumor analysis showed that conjugation of doxorubicin with aptamer significantly enhances targeted therapy against tumors while minimizing overall adverse effects on mice health.

ANXA1 Binds and Stabilizes EphA2 to Promote Nasopharyngeal Carcinoma Growth and Metastasis

Overexpression of ANXA1 and EphA2 has been linked to various cancers and both proteins have attracted considerable attention for the development of new anticancer drugs. Here we report that ANXA1 competes with Cbl for binding EphA2 and increases its stability by inhibiting Cbl-mediated EphA2 ubiquitination and degradation in nasopharyngeal carcinoma (NPC). Binding of ANXA1 to EphA2 promoted NPC cell growth and metastasis in vitro and in vivo by elevating EphA2 levels and increasing activity of EphA2 oncogenic signaling (pS897-EphA2). Expression of ANXA1 and EphA2 was positively correlated and both were significantly higher in NPC tissues than in the normal nasopharyngeal epithelial tissues. Patients with high expression of both proteins presented poorer disease-free survival and overall survival relative to patients with high expression of one protein alone. Furthermore, amino acid residues 20-30aa and 28-30aa of the ANXA1 N-terminus bound EphA2. An 11 amino acid-long ANXA1-derived peptide (EYVQTVKSSKG) was developed on the basis of this N-terminal region, which disrupted the connection of ANXA1 with EphA2, successfully downregulating EphA2 expression and dramatically suppressing NPC cell oncogenicity in vitro and in mice. These findings suggest that ANXA1 promotes NPC growth and metastasis via binding and stabilization of EphA2 and present a strategy for targeting EphA2 degradation and treating NPC with a peptide. This therapeutic strategy may also be extended to other cancers with high expression of both proteins. SIGNIFICANCE: These findings show that EphA2 is a potential target for NPC therapeutics and an ANXA1-derived peptide suppresses NPC growth and metastasis. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/20/4386/F1.large.jpg.

Upregulation of annexin A1 protein expression in the intratumoral vasculature of human non-small-cell lung carcinoma and rodent tumor models

Annexin A1 (anxA1) is an immunomodulatory protein that has been proposed as a tumor vascular target for antitumor biologic agents, yet to date the vascular expression of anxA1 in specific tumor indications has not been systematically assessed. Attempts to evaluate vascular anxA1 expression by immunohistochemistry are complicated by a lack of available antibodies that are both specific for anxA1 and bind the N-terminal–truncated form of anxA1 that has previously been identified in tumor vasculature. To study the vascular expression pattern of anxA1 in non–small-cell lung carcinoma (NSCLC), we isolated an antibody capable of binding N-terminal–truncated anxA1_27-346 and employed it in immunohistochemical studies of human lung specimens. Lung tumor specimens evaluated with this antibody revealed vascular (endothelial) anxA1 expression in five of eight tumor samples studied, but no vascular anxA1 expression was observed in normal lung tissue. Tumor microarray analysis further demonstrated positive vascular staining for anxA1 in 30 of 80 NSCLC samples, and positive staining of neoplastic cells was observed in 54 of 80 samples. No correlation was observed between vascular and parenchymal anxA1 expression. Two rodent tumor models, B16-F10 and Py230, were determined to have upregulated anxA1 expression in the intratumoral vasculature. These data validate anxA1 as a potential vascular anti-tumor target in a subset of human lung tumors and identify rodent models which demonstrate anxA1 expression in tumor vasculature.

Nuclear Tau, p53 and Pin1 Regulate PARN-Mediated Deadenylation and Gene Expression

While nuclear tau plays a role in DNA damage response (DDR) and chromosome relaxation, the mechanisms behind these functions are not fully understood. Here, we show that tau forms complex(es) with factors involved in nuclear mRNA processing such as tumor suppressor p53 and poly(A)-specific ribonuclease (PARN) deadenylase. Tau induces PARN activity in different cellular models during DDR, and this activation is further increased by p53 and inhibited by tau phosphorylation at residues implicated in neurological disorders. Tau's binding factor Pin1, a mitotic regulator overexpressed in cancer and depleted in Alzheimer's disease (AD), also plays a role in the activation of nuclear deadenylation. Tau, Pin1 and PARN target the expression of mRNAs deregulated in AD and/or cancer. Our findings identify novel biological roles of tau and toxic effects of hyperphosphorylated-tau. We propose a model in which factors involved in cancer and AD regulate gene expression by interactions with the mRNA processing machinery, affecting the transcriptome and suggesting insights into alternative mechanisms for the initiation and/or developments of these diseases.

Identification of Predictive Proteins and Biological Pathways for the Tumorigenicity of Vestibular Schwannoma by Proteomic Profiling

PURPOSE

Vestibular schwannomas (VSs) are benign tumors that account for 8-10% of all intracranial tumors. So far, the tumorigenesis of VS has not been fully elucidated. This study is designed to identify differently expressed proteins involved in VS tumorigenesis.

EXPERIMENTAL DESIGN

An isobaric tag is used for relative and absolute quantification (iTRAQ) approach to characterize the protein expression profiles from pooled VS tissues (n = 12) and pooled matched normal vestibular tissues (n = 12).

RESULTS

A total of 933 differentially expressed proteins are identified between VS and the matched normal vestibular tissues, with 489 being upregulated and 444 being downregulated. Bioinformatics analyses are performed according to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses. Several of the differentially expressed proteins are validated by western blotting analyses, and upregulation of LGALS1, ANXA1, GRB2, and STAT1 is validated in VS tissue by immunohistochemistry.

CONCLUSIONS AND CLINICAL RELEVANCE

The study represents the successful application of iTRAQ technology to an investigation of VS. Many of the differentially expressed proteins identified here have not been linked to VS before, and these dysregulated proteins may provide potential biomarkers for human VS diagnosis.

Annexin A1 peptide and endothelial cell-conditioned medium modulate cervical tumorigenesis

Cervical cancer is one of the leading causes of cancer death in women worldwide, and its tumorigenesis can be influenced by the microenvironment. The anti-inflammatory protein annexin A1 (ANXA1) has been reported to be associated with cancer progression and metastasis, suggesting that it plays a role in regulating tumour cell proliferation. Here, we examined the effect of the N-terminal peptide Ac2-26 of ANXA1 on the HaCaT cell line (normal) and HeLa cell line (cervical cancer) co-cultured with endothelium cell-conditioned medium (HMC). Treatment with Ac2-26 decreased proliferation and increased motility of cervical cancer cells, but did not affect cellular morphology or viability. Combined HMC stimulus and Ac2-26 treatment resulted in an increase in apoptotic HeLa cells, upregulated expression of MMP2, and downregulated expression of COX2,EP3 and EP4. In conclusion, Ac2-26 treatment may modulate cellular and molecular mechanisms underlying cervical carcinogenesis.

Determination of eumelanin and pheomelanin in melanomas using solid-phase extraction and high performance liquid chromatography-diode array detection (HPLC-DAD) analysis

Determination of eumelanin and pheomelanin in melanomas that exhibit different pigmentation was carried using a solid-phase extraction (SPE) preparation method based on weak anion exchange chemistry. This extraction significantly enhanced the chromatographic profile obtained by reverse phase high performance liquid chromatography-diode array detection (RP-HPLC-DAD). The SPE method was developed using aqueous standards of melanin markers: thiazole-2,4,5-tricarboxylic acid (TTCA), thiazole-4,5-dicarboxylic acid (TDCA), pyrrole-2,3-dicarboxylic acid (PDCA) and pyrrole-2,3,5-tricarboxylic acid (PTCA) and non-pigmented cell lines spiked with those markers. An excellent average recovery, above 90%, was obtained for the four markers with a relative standard deviation below 7%. We have also optimized the stationary phase and the mobile phase (phosphate concentration and pH) to improve sensitivity and to reduce the analysis time. Elution of the four markers is achieved in 5 min and total analysis of biological samples is completed in 15 min. The quantification limits for TDCA, TTCA, PDCA and PTCA are 60, 50, 47 and 48 ng/mL respectively. Furthermore, DAD detection improves the marker identification in complex matrices through the analysis of UV spectra. We have successfully applied this method to melanoma tumors and cells. Murine B16BL6 tumor are highly pigmented with mostly eumelanin (98.1% of eumelanin) while human SK-MEL-3 tumor contain about 30% pheomelanin. B16BL6 and B16F10 are eumelanic cells lines and NHEM melanocytes contain about 24% of pheomelanin.

Annexin A1-suppressed autophagy promotes nasopharyngeal carcinoma cell invasion and metastasis by PI3K/AKT signaling activation

Annexin A1 (ANXA1) is dysregulated in the various tumors. However, the role and mechanism of ANXA1 in the cancers are poorly understood. In this study, we first showed a clinically positive correlation between ANXA1 and autophagy-associated protein SQSTM1 expression in nasopharyngeal carcinoma (NPC) and ANXA1-regulating SQSTM1 expression through autophagy, and further demonstrated that ANXA1 inhibited BECN1 and ATG5-dependent autophagy in the NPC cells. Using phospho-kinase antibody array to identify signaling through which ANXA1 regulated NPC cell autophagy, we found that ANXA1-suppressed autophagy was associated with PI3K/AKT signaling activation. We also showed that ANXA1 expression was significantly increased in the NPCs with metastasis relative to NPCs without metastasis and positively correlated with lymphonode and distant metastasis; high ANXA1 expression in the NPC cells promoted in vitro tumor cell migration and invasion and in vivo metastasis. Lastly, we showed that inhibition of autophagy restored the ability of tumor cell migration and invasion, epithelial–mesenchymal transition (EMT)-like alterations and in vivo metastasis in the ANXA1 knockdown NPC cells with autophagy activation; ANXA1-suppresed autophagy induced EMT-like alterations possibly by inhibiting autophagy-mediated degradation of Snail. Our data suggest that ANXA1-suppressed autophagy promotes NPC cell migration, invasion and metastasis by activating PI3K/AKT signaling pathway, highlighting that the activation of autophagy may inhibit metastasis of NPC with high ANXA1 expression.

Enhanced antitumor effect of combination of annexin A1 knockdown and bortezomib treatment in multiple myeloma in vitro and in vivo

Bortezomib (BTZ) is one of the most frequently used drugs in treatment of multiple myeloma (MM), but drug-resistance often occurs and limits its clinical efficacy. Annexin A1 (ANXA1) is upregulated in MM, and its knockdown enhances chemosensitivity in MM. However, whether ANXA1 inhibition can increase antitumor activity of BTZ in MM cells remains unknown. In the present study, Cell Counting Kit-8 (CCK-8) and colony formation assays showed that ANXA1 silencing combined with BTZ treatment led to a more significant inhibition of MM cell proliferation than each treatment alone. Cell apoptosis was dramatically promoted in MM cells following silencing of ANXA1 and BTZ administration versus that in ANXA1-silenced alone or BTZ-treated alone cells, as evidenced by decreased expression of phosphorylated signal transducers and activators of transcription 3 and BCL2, and increased expression of BAX. Moreover, we demonstrated that the levels of IL-6 and IL-23 were markedly downregulated in ANXA1-silenced and BTZ-treated MM cells. Furthermore, the combination of ANXA1 knockdown and BTZ treatment distinctly suppressed tumor growth in vivo compared with BTZ treatment alone. Taken together, our results show that downregulation of ANXA1 enhances antitumor activity of BTZ in MM in vitro and in vivo, indicating that ANXA1 may be a promising target for enhancing the chemosensitivity of MM to BTZ.

Inhibition of the AnxA1/FPR1 autocrine axis reduces MDA-MB-231 breast cancer cell growth and aggressiveness in vitro and in vivo

Breast Cancer (BC) is a highly heterogeneous disease whose most aggressive behavior is displayed by triple-negative breast cancer (TNBC), which lacks an efficient targeted therapy. Despite its controversial role, one of the proteins that having been linked with BC is Annexin A1 (AnxA1), which is a Ca⁺² binding protein that acts modulating the immune system, cell membrane organization and vesicular trafficking. In this work we analyzed tissue microarrays of BC samples and observed a higher expression of AnxA1 in TNBCs and in lymph node metastasis. We also observed a positive correlation in primary tumors between expression levels of AnxA1 and its receptor, FPR1. Despite displaying a lesser strength, this correlation also exists in BC lymph node metastasis. In agreement, we have found that AnxA1 was highly expressed and secreted in the TNBC cell line MDA-MB-231 that also expressed high levels of FPR1. Furthermore, we demonstrated, by using the specific FPR1 inhibitor Cyclosporin H (CsH) and the immunosuppressive drug Cyclosporin A (CsA), the existence of an autocrine signaling of AnxA1 through the FPR1. Such signaling, elicited by AnxA1 upon its secretion, increased the aggressiveness and survival of MDA-MB-231 cells. In this manner, we demonstrated that CsA works very efficiently as an FPR1 inhibitor. Finally, by using CsA, we demonstrated that FPR1 inhibition decreased MDA-MB-231 tumor growth and metastasis formation in nude mice. These results indicate that FPR1 inhibition could be a potential intervention strategy to manage TNBCs displaying the characteristics of MDA-MB-231 cells. FPR1 inhibition can be efficiently achieved by CsA.

Secretomes reveal several novel proteins as well as TGF-β1 as the top upstream regulator of metastatic process in breast cancer

PURPOSE

Metastatic breast cancer is resistant to many conventional treatments and novel therapeutic targets are needed. We previously isolated subsets of 4T1 murine breast cancer cells which metastasized to liver (4TLM), brain (4TBM), and heart (4THM). Among these cells, 4TLM is the most aggressive one, demonstrating mesenchymal phenotype. Here we compared secreted proteins from 4TLM, 4TBM, and 4THM cells and compared with that of hardly metastatic 67NR cells to detect differentially secreted factors involved in organ-specific metastasis.

METHOD AND RESULTS

Label-free LC-MS/MS proteomic technique was used to detect the differentially secreted proteins. Eighty-five of over 500 secreted proteins were significantly altered in metastatic breast cancer cells. Differential expression of several proteins such as fibulin-4, Bone Morphogenetic Protein 1, TGF-β1 MMP-3, MMP-9, and Thymic Stromal Lymphopoietin were further verified using ELISA or Western blotting. Many of these identified proteins were also present in human metastatic breast carcinomas. Annexin A1 and A5, laminin beta 1, Neutral alpha-glucosidase AB were commonly found at least in three out of six studies examined here. Ingenuity Pathway Analysis showed that proteins differentially secreted from metastatic cells are involved primarily in carcinogenesis and TGF-β1 is the top upstream regulator in all metastatic cells.

CONCLUSIONS

Cells metastasized to different organs displayed significant differences in several of secreted proteins. Proteins differentially altered were fibronectin, insulin-like growth factor-binding protein 7, and Procollagen-lysine, 2-oxoglutarate 5-dioxygenase 1. On the other hand, many exosomal proteins were also common to all metastatic cells, demonstrating involvement of key universal factors in distant metastatic process.

ANXA1 affects cell proliferation, invasion and epithelial-mesenchymal transition of oral squamous cell carcinoma

Annexin A1 (ANXA1) acts either as a tumor suppressor or an oncogene in different tumor types. Several clinical studies revealed that the expression of ANXA1 is associated with the pathologic differentiation grade in oral squamous cell carcinoma (OSCC) patients. However, the direct function of ANXA1 in OSCC progression has remained to be fully clarified. The present study was designed to investigate the role of ANXA1 in OSCC cell proliferation and invasion in vitro. Furthermore, whether ANXA1 was involved in transforming growth factor β1 (TGFβ1)/epidermal growth factor (EGF)-induced epithelial-mesenchymal transition (EMT) in OSCC was explored. Tca-8113 and SCC-9 cells were transfected with ANXA1-pcDNA3.1 plasmid to overexpress ANXA1. Subsequently, cell proliferation and invasion were examined using MTT and Transwell-Matrigel invasion assays. TGFβ1 and EGF were used to induce EMT in Tca-8113 and SCC-9 cells, and the expression of epithelial (E)-cadherin, neural (N)-cadherin and vimentin was determined by western blot analysis. The results demonstrated that ANXA1 overexpression induced a significant decrease of cell growth and invasiveness in Tca-8113 and SCC-9 cells. The expression of E-cadherin was significantly increased, while the expression of vimentin and N-cadherin was significantly decreased in ANXA1-overexpressing Tca-8113 and SCC-9 cells. ANXA1 expression was significantly decreased in TGFβ1/EGF-treated cells. Furthermore TGFβ1/EGF-induced EMT in OSCC cell lines was attenuated by ANXA1 overexpression. In conclusion, to the best of our knowledge, the present study was the first to evidence that ANXA1 inhibits OSCC cell proliferation and invasion in vitro. TGFβ1/EGF-induced EMT was reversed by ANXA1 in OSCC. ANXA1 was suggested to be a potential marker for OSCC as well as a novel treatment.

Heterogeneity of mast cells and expression of Annexin A1 protein in a second degree burn model with silver sulfadiazine treatment

Mast cells (MCs) participate in all stages of skin healing and one of their mediators is the Annexin A1 protein (AnxA1), linked to inflammation, proliferation, migration and apoptosis processes, but not studied in thermal burns yet. Therefore, our objectives were to evaluate the behavior of MCs and AnxA1 in a second degree burn model, treated or not with silver sulfadiazine 1% (SDP 1%) and associated to macrophages quantification and cytokines dosages. MCs counts showed few cells in the early stages of repair but increased MCs in the final phases in the untreated group. The normal skin presented numerous tryptase-positive MCs that were reduced after burning in all analyzed periods. Differently, few chymase-positive MCs were observed in the early stages of healing, however, increased chymase-positive MCs were found at the final phase in the untreated group. MCs also showed high immunoreactivity for AnxA1 on day 3 in both groups. In the tissue there was a strong protein expression in the early stages of healing, but in the final phases only in the SDP treated animals. TNF-α, IL-1β, IL-6, IL-10 and MCP-1 levels and macrophages quantification were increased in inflammation and reepithelialization phases. Reduced IL-1β, IL-6 and IL-10 levels and numerous macrophages occurred in the treated animals during tissue repair. Our results indicate modulation in the profile of MCs and AnxA1expression during healing by the treatment with SDP 1%, pointing them as targets for therapeutic interventions on skin burns.

Identification of specific biomarkers for gastric adenocarcinoma by ITRAQ proteomic approach

The aim of this study was to identify biomarkers for gastric cancer (GC) by iTRAQ. Using proteins extracted from a panel of 4 pairs of gastric adenocarcinoma samples (stage III-IV, Her-2 negative), we identified 10 up regulated and 9 down regulated proteins in all four pairs of GC samples compared to adjacent normal gastric tissue. The up regulated proteins are mainly involved in cell motility, while the down regulated proteins are mitochondrial enzymes involved in energy metabolism. The expression of three up regulated proteins (ANXA1, NNMT, fibulin-5) and one of the down regulated proteins (UQCRC1) was validated by Western Blot in 97 GC samples. ANXA1 was up regulated in 61.36% of stage I/II GC samples compared to matched adjacent normal gastric tissue, and its expression increased further in stage III/IV samples. Knockdown of ANXA1 by siRNA significantly inhibited GC cell migration and invasion, whereas over expression of ANXA1 promoted migration and invasion. We found decreased expression of UQCRC1 in all stages of GC samples. Our data suggest that increased cell motility and decreased mitochondrial energy metabolism are important hallmarks during the development of GC.

Annexin A1 contributes to pancreatic cancer cell phenotype, behaviour and metastatic potential independently of Formyl Peptide Receptor pathway

Annexin A1 (ANXA1) is a Ca(2+)-binding protein over-expressed in pancreatic cancer (PC). We recently reported that extracellular ANXA1 mediates PC cell motility acting on Formyl Peptide Receptors (FPRs). Here, we describe other mechanisms by which intracellular ANXA1 could mediate PC progression. We obtained ANXA1 Knock-Out (KO) MIA PaCa-2 cells using the CRISPR/Cas9 genome editing technology. LC-MS/MS analysis showed altered expression of several proteins involved in cytoskeletal organization. As a result, ANXA1 KO MIA PaCa-2 partially lost their migratory and invasive capabilities with a mechanism that appeared independent of FPRs. The acquisition of a less aggressive phenotype has been further investigated in vivo. Wild type (WT), PGS (scrambled) and ANXA1 KO MIA PaCa-2 cells were engrafted orthotopically in SCID mice. No differences were found about PC primary mass, conversely liver metastatization appeared particularly reduced in ANXA1 KO MIA PaCa-2 engrafted mice. In summary, we show that intracellular ANXA1 is able to preserve the cytoskeleton integrity and to maintain a malignant phenotype in vitro. The protein has a relevant role in the metastatization process in vivo, as such it appears attractive and suitable as prognostic and therapeutic marker in PC progression.

Annexin A1 localization and its relevance to cancer

Annexin A1 (ANXA1) is a Ca(2+)-regulated phospholipid-binding protein involved in various cell processes. ANXA1 was initially widely studied in inflammation resolution, but its overexpression was later reported in a large number of cancers. Further in-depth investigations have revealed that this protein could have many roles in cancer progression and act at different levels (from cancer initiation to metastasis). This is partly due to the location of ANXA1 in different cell compartments. ANXA1 can be nuclear, cytoplasmic and/or membrane associated. This last location allows ANXA1 to be proteolytically cleaved and/or to become accessible to its cognate partners, the formyl-peptide receptors. Indeed, in some cancers, ANXA1 is found at the cell surface, where it stimulates formyl-peptide receptors to trigger oncogenic pathways. In the present review, we look at the different locations of ANXA1 and their association with the deregulated pathways often observed in cancers. We have specifically detailed the non-classic pathways of ANXA1 externalization, the significance of its cleavage and the role of the ANXA1-formyl-peptide receptor complex in cancer progression.

Knockdown of ANXA1 suppresses the biological behavior of human NSCLC cells in vitro

Annexin A1 (ANXA1) is a member of the annexin superfamily. Previous studies have reported that ANXA1 is highly expressed in various types of malignant tumor; however, its role in the progression of non‑small cell lung cancer (NSCLC) remains to be fully clarified. The present study aimed to investigate the oncogenic role of ANXA1 in NSCLC cells in vitro. RNA interference was used to downregulate ANXA1 expression in A549 and H1299 cells using a small interfering RNA lentiviral vector. Subsequently, cell proliferation and migration were detected using Cell Counting kit‑8, clone formation, wound healing and Transwell chamber assays. Successful transfection was confirmed using fluorescence microscopy, which demonstrated that ANXA1 had been efficiently inhibited. ANXA1 knockdown suppressed the proliferation, migration and invasion of NSCLC cells. In conclusion, the present study provided evidence suggesting that ANXA1 may contribute to the growth and invasion of NSCLC cell lines, and ANXA1 may be exploited as an in vitro therapeutic target for the treatment of NSCLC.

Proteome Differences between Hepatitis B Virus Genotype-B- and Genotype-C-Induced Hepatocellular Carcinoma Revealed by iTRAQ-Based Quantitative Proteomics

Hepatitis B virus (HBV) is the main cause of hepatocellular carcinoma (HCC) in southeast Asia where HBV genotype B and genotype C are the most prevalent. Viral genotypes have been reported to significantly affect the clinical outcomes of HCC. However, the underlying molecular differences among different genotypes of HBV virus infected HCC have not been revealed. Here, we applied isobaric tags for relative and absolute quantitation (iTRAQ) technology integrated with liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis to identify the proteome differences between the HBV genotypes B- and C-induced HCC. In brief, a total of 83 proteins in the surrounding noncancerous tissues and 136 proteins in the cancerous tissues between HBV genotype-B- and genotype-C-induced HCC were identified, respectively. This information revealed that there might be different molecular mechanisms of the tumorigenesis and development of HBV genotypes B- and C-induced HCC. Furthermore, our results indicate that the two proteins ARFIP2 and ANXA1 might be potential biomarkers for distinguishing the HBV genotypes B- and C-induced HCC. Thus, the quantitative proteomic analysis revealed molecular differences between the HBV genotypes B- and C-induced HCC, and might provide fundamental information for further deep study.

Annexin A1 expression in a pooled breast cancer series: association with tumor subtypes and prognosis

BACKGROUND

Annexin A1 (ANXA1) is a protein related with the carcinogenesis process and metastasis formation in many tumors. However, little is known about the prognostic value of ANXA1 in breast cancer. The purpose of this study is to evaluate the association between ANXA1 expression, BRCA1/2 germline carriership, specific tumor subtypes and survival in breast cancer patients.

METHODS

Clinical-pathological information and follow-up data were collected from nine breast cancer studies from the Breast Cancer Association Consortium (BCAC) (n = 5,752) and from one study of familial breast cancer patients with BRCA1/2 mutations (n = 107). ANXA1 expression was scored based on the percentage of immunohistochemical staining in tumor cells. Survival analyses were performed using a multivariable Cox model.

RESULTS

The frequency of ANXA1 positive tumors was higher in familial breast cancer patients with BRCA1/2 mutations than in BCAC patients, with 48.6 % versus 12.4 %, respectively; P <0.0001. ANXA1 was also highly expressed in BCAC tumors that were poorly differentiated, triple negative, EGFR-CK5/6 positive or had developed in patients at a young age. In the first 5 years of follow-up, patients with ANXA1 positive tumors had a worse breast cancer-specific survival (BCSS) than ANXA1 negative (HRadj = 1.35; 95 % CI = 1.05-1.73), but the association weakened after 10 years (HRadj = 1.13; 95 % CI = 0.91-1.40). ANXA1 was a significant independent predictor of survival in HER2+ patients (10-years BCSS: HRadj = 1.70; 95 % CI = 1.17-2.45).

CONCLUSIONS

ANXA1 is overexpressed in familial breast cancer patients with BRCA1/2 mutations and correlated with poor prognosis features: triple negative and poorly differentiated tumors. ANXA1 might be a biomarker candidate for breast cancer survival prediction in high risk groups such as HER2+ cases.

Role of intracellular and extracellular annexin A1 in migration and invasion of human pancreatic carcinoma cells

BACKGROUND

Annexin A1 (ANXA1), a 37 kDa multifunctional protein, is over-expressed in tissues from patients of pancreatic carcinoma (PC) where the protein seems to be associated with malignant transformation and poor prognosis.

METHODS

The expression and localization of ANXA1 in MIA PaCa-2, PANC-1, BxPC-3 and CAPAN-2 cells were detected by Western Blotting and Immunofluorescence assay. Expression and activation of Formyl Peptide Receptors (FPRs) were shown through flow cytometry/PCR and FURA assay, respectively. To investigate the role of ANXA1 in PC cell migration and invasion, we performed in vitro wound-healing and matrigel invasion assays.

RESULTS

In all the analyzed PC cell lines, a huge expression and a variable localization of ANXA1 in sub-cellular compartments were observed. We confirmed the less aggressive phenotype of BxPC-3 and CAPAN-2 compared with PANC-1 and MIA PaCa-2 cells, through the evaluation of Epithelial-Mesenchymal Transition (EMT) markers. Then, we tested MIA PaCa-2 and PANC-1 cell migration and invasiveness rate which was inhibited by specific ANXA1 siRNAs. Both the cell lines expressed FPR-1 and -2. Ac2-26, an ANXA1 mimetic peptide, induced intracellular calcium release, consistent with FPR activation, and significantly increased cell migration/invasion rate. Interestingly, in MIA PaCa-2 cells we found a cleaved form of ANXA1 (33 kDa) that localizes at cellular membranes and is secreted outside the cells, as confirmed by MS analysis. The importance of the secreted form of ANXA1 in cellular motility was confirmed by the administration of ANXA1 blocking antibody that inhibited migration and invasion rate in MIA PaCa-2 but not in PANC-1 cells that lack the 33 kDa ANXA1 form and show a lower degree of invasiveness. Finally, the treatment of PANC-1 cells with MIA PaCa-2 supernatants significantly increased the migration rate of these cells.

CONCLUSION

This study provides new insights on the role of ANXA1 protein in PC progression. Our findings suggest that ANXA1 protein could regulate metastasis by favouring cell migration/invasion intracellularly, as cytoskeleton remodelling factor, and extracellularly like FPR ligand.

Increased expression of annexin A1 predicts poor prognosis in human hepatocellular carcinoma and enhances cell malignant phenotype

Annexin A1 (ANXA1) belongs to the annexin superfamily of proteins, which contribute to the pathological consequence and sequelae of most serious human diseases. Recent studies have reported diverse roles of ANXA1 in various human cancers; however, its involvement in human hepatocellular carcinoma (HCC) still remains controversial. To investigate the expression pattern of ANXA1 in HCC tissues and evaluate its associations with tumor progression and patients' prognosis, immunohistochemistry was performed using 160 pairs of formalin-fixed and paraffin-embedded cancerous and adjacent non-cancerous tissues from patients with HCC. Then, the associations between ANXA1 expression, clinicopathological characteristics, and prognosis of HCC patients were statistically evaluated. In vitro migration and invasion assays of siRNA-targeted ANXA1-transfected cells were further performed. As a result, the expression levels of ANXA1 protein in HCC tissues were significantly higher than those in adjacent non-cancerous tissues (P < 0.001). High ANXA1 expression was closely correlated with advanced TNM stage (P = 0.001) and high Edmondson grade (P = 0.02). Then, univariate and multivariate analyses showed that the status of ANXA1 expression was an independent predictor for overall survival of HCC patients. Furthermore, knockdown of ANXA1 by transfection of siRNA-ANXA1 could suppress the migration and invasion abilities of HCC cells in vitro. Collectively, these findings offer the convincing evidence that ANXA1 may play an important role in HCC progression and can be used as a molecular marker to predict prognosis and a potential target for therapeutic intervention of HCC.