Targeted tumor coating with antigenic, CTL-recognizable peptides via Annexin A5 chimeric constructs following chemotherapy redirects adaptive CD8+ T cell immunity for tumor clearance.
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ABSTRACT:
SUBMITTER: Kang TH
PROVIDER: S-EPMC8166831 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Annexin A5 (ANXA5), which is known as a protein with anticoagulative function, may play a role in triglyceride biosynthesis. Triglycerides are involved in lipid and energy metabolism, which are important in the elucidation of obesity. To investigate the association between single-nucleotide polymorphisms (SNPs) of ANXA5 and obesity in a Korean population, 372 participants (213 overweight/obese individuals and 159 control subjects) were enrolled from the Kyung Hee University Medical Center and Keimyung University Dongsan Medical Center. The genotypes of five SNPs (rs12510548, rs4240260, rs3756281, rs13136094 and rs6534313) were evaluated in ANXA5 using the multiple logistic regression analysis with the codominant 1, codominant 2, dominant, recessive and log-additive models. The genotype and allele frequencies of the five investigated SNPs exhibited significant differences between the control and the overweight/obese groups: rs12510548 (P=0.004 in the codominant 2 model, P=0.0019 in the recessive model, P=0.027 in the log-additive model and P=0.026 in allele frequencies); rs4240260 (P=0.002 and Fisher's exact P=0.0006 in the codominant 2 model, P=0.0007 and Fisher's exact P=0.0007 in the recessive model, P=0.020 and Fisher's exact P=0.0019 in the log-additive model and P=0.020 in allele frequencies); rs3756281 (P=0.016 in the codominant 2 model and P=0.0094 in the recessive model); rs13136094 (P=0.0030 and Fisher's exact P=0.0011 in the codominant 2 model, P=0.0012 and Fisher's exact P=0.0013 in the recessive model, P=0.034 and Fisher's exact P=0.0035 in the log-additive model and P=0.024 in allele frequencies); and rs6534313 (P=0.0010 and Fisher's exact P=0.0003 in the codominant 2 model, P=0.0003 and Fisher's exact P=0.0003 in the recessive model, P=0.0075 and Fisher's exact P=0.0010 in the log-additive model and P=0.005 in allele frequencies). Two haplotypes were weakly associated with obesity (GGATG, P=0.037 and CAGCC, P=0.020). Results of the present study suggested that ANXA5 may be associated with the development of obesity in a Korean population.
| S-EPMC3917105 | biostudies-literature
Project description:The interaction between immune cells and phosphatidylserine (PS) molecules exposed on the surface of apoptotic-tumor bodies, such as those induced by chemotherapies, contributes to the formation of an immunosuppressive tumor microenvironment (TME). Annexin A5 (AnxA5) binds with high affinity to PS externalized by apoptotic cells, thereby hindering their interaction with immune cells. Here, we show that AnxA5 administration rescue the immunosuppressive state of the TME induced by chemotherapy. Due to the preferential homing of AnxA5 to the TME enriched with PS+ tumor cells, we demonstrate in vivo that fusing tumor-antigen peptide to AnxA5 significantly enhances its immunogenicity and antitumor efficacy when administered after chemotherapy. Also, the therapeutic antitumor effect of an AnxA5-peptide fusion can be further enhanced by administration of other immune checkpoint inhibitors. Our findings support the administration of AnxA5 following chemotherapy as a promising immune checkpoint inhibitor for cancer treatment.
| S-EPMC7048819 | biostudies-literature
Project description:Techniques for visualizing cell death can provide noninvasive assessment of both disease states and response to therapeutic intervention. The purpose of this study was to develop and evaluate a multimodal imaging nanoplatform for the detection of cell death. In this study, we evaluated 111In-labeled annexin A5-conjugated core-cross-linked polymeric micelles (CCPMs) for multimodal imaging of cell death in various disease models. Three different models were conducted, including tumor apoptosis, hepatic apoptosis, and inflammation. Both micro single-photon emission tomography/computed tomography (?SPECT/CT) and fluorescence molecular tomography (FMT) were performed. Biodistribution and immunohistochemistry assays were carried out to validate the selectivity of cell death imaging. In all disease models, cell death was clearly visualized by both ?SPECT/CT and FMT. In contrast, there was relatively low signal in the corresponding tissues of control mice. Moreover, the radioactive signal from 111In-labeled annexin A5-CCPM colocalized with its fluorescence signal, and both signals were confined to regions of dying cells. 111In-labeled annexin A5-CCPM allows visualization of cell death by both nuclear and optical techniques at the whole-body level as well as at the microscopic level. It has the potential to aid the diagnosis of disease states or tissue responses involving abnormal cell death.
| S-EPMC3893065 | biostudies-literature
Project description:Diurnal clearance phagocytosis by the retinal pigment epithelium (RPE) is a conserved efferocytosis process whose binding step is mediated by ?v?5 integrin receptors. Two related annexins, A5 (ANXA5) and A6 (ANXA6), share an ?v?5 integrin-binding motif. Here, we report that ANXA5, but not ANXA6, regulates the binding capacity for spent photoreceptor outer segment fragments or apoptotic cells by fibroblasts and RPE. Similar to ?v?5-deficient RPE, ANXA5-/- RPE in vivo lacks the diurnal burst of phagocytosis that follows photoreceptor shedding in wild-type retina. Increasing ANXA5 in cells lacking ?v?5 or increasing ?v?5 in cells lacking ANXA5 does not affect particle binding. Association of cytosolic ANXA5 and ?v?5 integrin in RPE in culture and in vivo further supports their functional interdependence. Silencing ANXA5 is sufficient to reduce levels of ?v?5 receptors at the apical phagocytic surface of RPE cells. The effect of ANXA5 on surface ?v?5 and on particle binding requires the C-terminal ANXA5 annexin repeat but not its unique N-terminus. These results identify a novel role for ANXA5 specifically in the recognition and binding step of clearance phagocytosis, which is essential to retinal physiology.This article has an associated First Person interview with the first author of the paper.
| S-EPMC6826004 | biostudies-literature
Project description:T-cell activation is a critical part of the adaptive immune system, enabling responses to foreign cells and external stimulus. In this process, T-cell antigen receptor (TCR) activation stimulates translocation of the downstream kinase PKCθ to the membrane, leading to NF-κB activation and thus transcription of relevant genes. However, the details of how PKCθ is recruited to the membrane remain enigmatic. It is known that annexin A5 (ANXA5), a calcium-dependent membrane-binding protein, has been reported to mediate PKCδ activation by interaction with PKCδ, a homologue of PKCθ, which implicates a potential role of ANXA5 involved in PKCθ signaling. Here we demonstrate that ANXA5 does play a critical role in the recruitment of PKCθ to the membrane during T-cell activation. ANXA5 knockout in Jurkat T cells substantially inhibited the membrane translocation of PKCθ upon TCR engagement and blocked the recruitment of CARMA1-BCL10-MALT1 signalosome, which provides a platform for the catalytic activation of IKKs and subsequent activation of canonical NF-κB signaling in activated T cells. As a result, NF-κB activation was impaired in ANXA5-KO T cells. T-cell activation was also suppressed by ANAX5 knockdown in primary T cells. These results demonstrated a novel role of ANXA5 in PKC translocation and PKC signaling during T-cell activation.
| S-EPMC7549025 | biostudies-literature
Project description:Eukaryotic cells possess a universal repair machinery that ensures rapid resealing of plasma membrane disruptions. Before resealing, the torn membrane is submitted to considerable tension, which functions to expand the disruption. Here we show that annexin-A5 (AnxA5), a protein that self-assembles into two-dimensional (2D) arrays on membranes upon Ca(2+) activation, promotes membrane repair. Compared with wild-type mouse perivascular cells, AnxA5-null cells exhibit a severe membrane repair defect. Membrane repair in AnxA5-null cells is rescued by addition of AnxA5, which binds exclusively to disrupted membrane areas. In contrast, an AnxA5 mutant that lacks the ability of forming 2D arrays is unable to promote membrane repair. We propose that AnxA5 participates in a previously unrecognized step of the membrane repair process: triggered by the local influx of Ca(2+), AnxA5 proteins bind to torn membrane edges and form a 2D array, which prevents wound expansion and promotes membrane resealing.
| S-EPMC3104517 | biostudies-literature
Project description:ObjectiveAnnexin A5 is a phosphatidylserine binding protein that binds dying cells in vivo. Annexin A5 is a potential molecular imaging agent to determine efficacy of anti-cancer therapy in patients. Its rapid clearance from circulation limits tumor uptake and, hence, its sensitivity. The aim of this study is to determine if non-invasive imaging of cell death in tumors will benefit from increasing circulation time of annexin A5 by increasing its size.ProceduresAnnexin A5 size was increased by complexation of biotinylated annexin A5 with Alexa-Fluor680-labeled streptavidin. The non-binding variant of annexin A5, M1234, was used as negative control. The HT29 colon carcinoma xenograft model in NMRI nude mice was used to measure tumor uptake in vivo. Tumor uptake of fluorescent annexin A5-variants was measured using non-invasive optical imaging.ResultsThe annexin A5-streptavidin complex (4 ? 1, moles:moles, Mw ? 200 kDa) binds phosphatidylserine-expressing membranes with a Hill-coefficient of 5.7 ± 0.5 for Ca2+-binding and an EC50 of 0.9 ± 0.1 mM Ca2+ (EC50 is the Ca2+ concentration required for half maximal binding)(annexin A5: Hill-coefficient 3.9 ± 0.2, EC50 1.5 ± 0.2 mM Ca2+). Circulation half-life of annexin A5-streptavidin is ± 21 minutes (circulation half-life of annexin A5 is ± 4 min.). Tumor uptake of annexin A5-streptavidin was higher and persisted longer than annexin A5-uptake but depended less on phosphatidylserine binding.ConclusionIncreasing annexin A5 size prolongs circulation times and increases tumor uptake, but decreases contribution of PS-targeting to tumor uptake and abolishes power to report efficacy of therapy.
| S-EPMC4011958 | biostudies-literature
Project description:Annexin A5 (anxA5) is a marker for apoptosis, but has also therapeutic potential in cardiovascular diseases, cancer, and, due to apoptotic mimicry, against dangerous viruses, which is limited by the short blood circulation. An 864-amino-acid XTEN polypeptide was fused to anxA5. XTEN864-anxA5 was expressed in Escherichia coli and purified using XTEN as tag. XTEN864-anxA5 was coupled with DTPA and indium-111. After intravenous or subcutaneous injection of 111In-XTEN864-anxA5, mouse blood samples were collected for blood half-life determination and organ samples for biodistribution using a gamma counter. XTEN864-anxA5 was labeled with 6S-IDCC to confirm binding to apoptotic cells using flow cytometry. To demonstrate targeting of atherosclerotic plaques, XTEN864-anxA5 was labeled with MeCAT(Ho) and administered intravenously to atherosclerotic ApoE-/- mice. MeCAT(Ho)-XTEN864-anxA5 was detected together with MeCAT(Tm)-MAC-2 macrophage antibodies by imaging mass cytometry (CyTOF) of aortic root sections. The ability of anxA5 to bind apoptotic cells was not affected by XTEN864. The blood half-life of XTEN864-anxA5 was 13 h in mice after IV injection, markedly longer than the 7-min half-life of anxA5. 96 h after injection, highest amounts of XTEN864-anxA5 were found in liver, spleen, and kidney. XTEN864-anxA5 was found to target the adventitia adjacent to atherosclerotic plaques. XTEN864-anxA5 is a long-circulating fusion protein that can be efficiently produced in E. coli and potentially circulates in humans for several days, making it a promising therapeutic drug.
| S-EPMC8370750 | biostudies-literature
Project description:The potency of immunotherapies targeting endogenous tumor antigens is hindered by immune tolerance. We created a therapeutic agent comprised of a tumor-homing module fused to a functional domain capable of selectively rendering tumor cells sensitive to foreign antigen-specific CD8(+) T cell-mediated immune attack, and thereby, circumventing concerns for immune tolerance. The tumor-homing module is comprised of a single-chain variable fragment (scFv) that specifically binds to mesothelin (Meso), which is commonly overexpressed in human cancers, including ovarian tumors. The functional domain is comprised of the Fc portion of IgG2a protein and foreign immunogenic CD8(+) T cell epitope flanked by furin cleavage sites (R), which can be recognized and cleaved by furin that is highly expressed in the tumor microenvironment. We show that our therapeutic protein specifically loaded antigenic epitope onto the surface of mesothelin-expressing tumor cells, rendering tumors susceptible to antigen-specific cytotoxic CD8(+) T lymphocytes (CTL)-mediated killing in vitro and in vivo. Our findings have important implications for bypassing immune tolerance to enhance cancer immunotherapy.
| S-EPMC3589158 | biostudies-literature
Project description:Imaging of apoptosis can allow noninvasive assessment of disease states and response to therapeutic intervention for a variety of diseases. The purpose of this study was to develop and evaluate a multimodal nanoplatform for the detection of apoptosis.To modulate the pharmacokinetics of annexin A5, a 36-kDa protein that binds specifically with phosphatidylserine, annexin A5 was conjugated to polyethylene glycol-coated, core-cross-linked polymeric micelles (CCPMs) dually labeled with near-infrared fluorescence fluorophores and a radioisotope ((111)In). To evaluate the specificity of the binding of annexin A5-CCPM to apoptotic cells, both fluorescence microscopy and cell-binding studies were performed in vitro. Pharmacokinetics, biodistribution, dual nuclear and optical imaging, and immunohistochemical studies were performed in 2 xenografted tumor models to evaluate the potential applications of annexin A5-CCPM.In cell-based studies, annexin A5-CCPM exhibited strongly specific binding to apoptotic tumor cells. This binding could be efficiently blocked by annexin A5. In mice, annexin A5-CCPM displayed a mean elimination half-life of 12.5 h. The mean initial concentration in blood was 22.4% of the injected dose/mL, and annexin A5-CCPM was mainly distributed in the central blood compartment. In mice bearing EL4 lymphoma treated with cyclophosphamide and etoposide and in mice bearing MDA-MB-468 breast tumors treated with poly(L-glutamic acid)-paclitaxel and cetuximab (IMC-C225) anti-epidermal growth factor receptor antibody, the tumor apoptosis was clearly visualized by both SPECT and fluorescence molecular tomography. In contrast, there was little accumulation of this nanoradiotracer in the tumors of untreated mice. The biodistribution data were consistent with the imaging data, with tumor-to-muscle and tumor-to-blood ratios of 38.8 and 4.1, respectively, in treated mice, and 14.8 and 2.2, respectively, in untreated mice bearing EL4 lymphoma. Moreover, further studies demonstrated that the conventional (99m)Tc-labeled hydrazinonicotinamide annexin A5 and the plain CCPM control exhibited significantly lower uptake in the tumors of the treated mice than annexin A5-CCPM. Immunohistochemistry staining study showed that radioactivity count correlated with fluorescence signal from the nanoparticles, and both signals colocalized with the region of tumor apoptosis.Annexin A5-CCPM allowed visualization of tumor apoptosis by both nuclear and optical techniques. The complementary information acquired with multiple imaging techniques should be advantageous in assessing and validating early response to therapy.
| S-EPMC3463236 | biostudies-literature