InVivoMAb anti-mouse CD47 (IAP)

Catalog #BE0270
Product Citations:
27
Clone:
MIAP301
Reactivities:
Mouse

$164.00 - $4,280.00

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Product Details

The MIAP301 monoclonal antibody reacts with mouse CD47 otherwise known as integrin-associated protein (IAP). CD47 is an approximately 50 kDa glycosylated five transmembrane protein that is ubiquitously expressed by both hematopoietic cells such as T and B lymphocytes, monocytes, platelets and erythrocytes and non-hematopoietic cells. CD47 is involved in a range of cellular processes, including apoptosis, proliferation, adhesion, and migration. Furthermore, it plays a key role in immune and angiogenic responses. CD47 is a receptor for thrombospondin-1 (TSP-1), a secreted glycoprotein that plays a role in vascular development and angiogenesis. CD47 Is has been found to be overexpressed in many different tumor cells. Because of this, anti-CD47 monoclonal antibodies have been proposed and studied as a therapeutic treatment for human cancers. The MIAP301 antibody has been shown to neutralize CD47 in vivo and in vitro.

Specifications

Isotype Rat IgG2a, κ
Recommended Isotype Control(s) InVivoMAb rat IgG2a isotype control, anti-trinitrophenol
Recommended Dilution Buffer InVivoPure pH 7.0 Dilution Buffer
Conjugation This product is unconjugated. Conjugation is available via our Antibody Conjugation Services.
Immunogen Intact CD47 purified from placenta
Reported Applications in vivo CD47 blockade
in vitro CD47 blockade
Immunofluorescence
Formulation PBS, pH 7.0
Contains no stabilizers or preservatives
Endotoxin <2EU/mg (<0.002EU/μg)
Determined by LAL gel clotting assay
Purity >95%
Determined by SDS-PAGE
Sterility 0.2 µm filtration
Production Purified from cell culture supernatant in an animal-free facility
Purification Protein G
RRID AB_2687793
Molecular Weight 150 kDa
Storage The antibody solution should be stored at the stock concentration at 4°C. Do not freeze.
in vivo CD47 blockade, in vitro CD47 blockade
Reed, M., et al. (2019). "Epithelial CD47 is critical for mucosal repair in the murine intestine in vivo" Nat Commun 10(1): 5004. PubMed

CD47 is a ubiquitously expressed transmembrane glycoprotein that regulates inflammatory responses and tissue repair. Here, we show that normal mice treated with anti-CD47 antibodies, and Cd47-null mice have impaired intestinal mucosal wound healing. Furthermore, intestinal epithelial cell (IEC)-specific loss of CD47 does not induce spontaneous immune-mediated intestinal barrier disruption but results in defective mucosal repair after biopsy-induced colonic wounding or Dextran Sulfate Sodium (DSS)-induced mucosal damage. In vitro analyses using primary cultures of CD47-deficient murine colonic IEC or human colonoid-derived IEC treated with CD47-blocking antibodies demonstrate impaired epithelial cell migration in wound healing assays. Defective wound repair after CD47 loss is linked to decreased epithelial β1 integrin and focal adhesion signaling, as well as reduced thrombospondin-1 and TGF-β1. These results demonstrate a critical role for IEC-expressed CD47 in regulating mucosal repair and raise important considerations for possible alterations in wound healing secondary to therapeutic targeting of CD47.

in vitro CD47 blockade
Liu, M., et al. (2019). "Metabolic rewiring of macrophages by CpG potentiates clearance of cancer cells and overcomes tumor-expressed CD47-mediated ‘don’t-eat-me’ signal" Nat Immunol 20(3): 265-275. PubMed

Macrophages enforce antitumor immunity by engulfing and killing tumor cells. Although these functions are determined by a balance of stimulatory and inhibitory signals, the role of macrophage metabolism is unknown. Here, we study the capacity of macrophages to circumvent inhibitory activity mediated by CD47 on cancer cells. We show that stimulation with a CpG oligodeoxynucleotide, a Toll-like receptor 9 agonist, evokes changes in the central carbon metabolism of macrophages that enable antitumor activity, including engulfment of CD47(+) cancer cells. CpG activation engenders a metabolic state that requires fatty acid oxidation and shunting of tricarboxylic acid cycle intermediates for de novo lipid biosynthesis. This integration of metabolic inputs is underpinned by carnitine palmitoyltransferase 1A and adenosine tri-phosphate citrate lyase, which, together, impart macrophages with antitumor potential capable of overcoming inhibitory CD47 on cancer cells. Our findings identify central carbon metabolism to be a novel determinant and potential therapeutic target for stimulating antitumor activity by macrophages.

in vivo CD47 blockade
Pan, Y., et al. (2019). "Single-cell RNA sequencing reveals compartmental remodeling of tumor-infiltrating immune cells induced by anti-CD47 targeting in pancreatic cancer" J Hematol Oncol 12(1): 124. PubMed

BACKGROUND: Human pancreatic ductal adenocarcinoma (PDAC) responds poorly to immune checkpoint inhibitor (ICPi). While the mechanism is not completely clear, it has been recognized that tumor microenvironment (TME) plays key roles. We investigated if targeting CD47 with a monoclonal antibody could enhance the response of PDAC to ICPi by altering the TME. METHODS: Using immunohistochemistry, we examined tumor-infiltrating CD68(+) pan-macrophages (CD68(+) M) and CD163(+) M2 macrophages (CD163(+) M2) and tumor expression of CD47 and PD-L1 proteins in 106 cases of PDAC. The efficacy of CD47 blockade was examined in xenograft models. CD45(+) immune cells from syngeneic tumor models were subjected to single-cell RNA-sequencing (scRNA-seq) by using the 10x Genomics pipeline. RESULTS: We found that CD47 expression correlated with the level of CD68(+) M but not CD163(+) M2. High levels of tumor-infiltrating CD68(+) M, CD163(+) M2, and CD47 expression were significantly associated with worse survival. CD47(high)/CD68(+) M(high) and CD47(high)/CD163(+) M2(high) correlated significantly with shorter survival, whereas CD47(low)/CD68(+) M(low) and CD47(low)/CD163(+) M2(low) correlated with longer survival. Intriguingly, CD47 blockade decreased the tumor burden in the Panc02 but not in the MPC-83 syngeneic mouse model. Using scRNA-seq, we showed that anti-CD47 treatment significantly remodeled the intratumoral lymphocyte and macrophage compartments in Panc02 tumor-bearing mice by increasing the pro-inflammatory macrophages that exhibit anti-tumor function, while reducing the anti-inflammatory macrophages. Moreover, CD47 blockade not only increased the number of intratumoral CD8(+) T cells, but also remodeled the T cell cluster toward a more activated one. Further, combination therapy targeting both CD47 and PD-L1 resulted in synergistic inhibition of PDAC growth in the MPC-83 but not in Panc02 model. MPC-83 but not Panc02 mice treated with both anti-CD47 and anti-PD-L1 showed increased number of PD-1(+)CD8(+) T cells and enhanced expression of key immune activating genes. CONCLUSION: Our data indicate that CD47 targeting induces compartmental remodeling of tumor-infiltrating immune cells of the TME in PDAC. Different PDAC mouse models exhibited differential response to the anti-CD47 and anti-PD-L1 blockade due to the differential effect of this combination treatment on the infiltrating immune cells and key immune activating genes in the TME established by the different PDAC cell lines.

in vivo CD47 blockade
Wu, L., et al. (2018). "Anti-CD47 treatment enhances anti-tumor T-cell immunity and improves immunosuppressive environment in head and neck squamous cell carcinoma" Oncoimmunology 7(4): e1397248. PubMed

Head and neck squamous cell carcinoma (HNSCC) is considered as an immunosuppressive disease, with impaired tumor-infiltrating T lymphocytes and increased suppressive immune cells. The efficacy of CD47 antibodies in immune checkpoint therapy is not clearly understood in HNSCC. In this study, human tissue microarrays and immunocompetent transgenic mouse models were used to explore the expression of CD47 and the use of CD47 antibodies in HNSCC. We identified overexpression of CD47 in HNSCC as compared with the control normal human tissue and also in HNSCC mouse models. The expression of CD47 also correlated with clinicopathological parameters as well as outcome. Furthermore, inhibition of CD47 delayed tumor growth and improved tumor microenvironment by stimulating effector T cells and decreasing suppressive immune cells and regulating the function of CD11b(+) Ly6G(+) MDSC. Our data suggest that CD47 blockade may be a potential immunotherapeutic target in human HNSCC.

in vivo CD47 blockade
Sallets, A., et al. (2018). "Enhancing immunotherapy of STING agonist for lymphoma in preclinical models" Blood Adv 2(17): 2230-2241. PubMed

Direct activation of tumor infiltrating antigen-presenting cells (APCs) by intratumoral injection of STING agonists (STINGa) leads to regression of the treated lymphoma tumor. Because STING activation induces apoptosis in lymphoma cells in vitro, we distinguished between the direct therapeutic vs the indirect immunotherapeutic properties of STINGa in vivo. Employing wild-type or STING knockout hosts bearing either wild-type or STING knockout tumor cells, we demonstrated that local tumor regression is totally dependent on STING expression by the host and is therefore immune mediated. However, distant untreated tumors are weakly affected after injection of STINGa to a single tumor site. Therefore, using the STINGa currently being tested in clinical trials, we screened for immunomodulatory agents that could synergize with the STING pathway to induce a systemic antitumor immune response and regression of distant tumors. We combined the STINGa with agents that improve APC or T-cell function. We found that modulation of both APCs and T cells can enhance control of distant lymphoma tumors by STINGa. In particular, adding an anti-GITR antibody induced lymphocyte expansion in the lymph node draining the treated site followed by increased T-cell infiltration in the distant tumor. Furthermore, more of these CD8 T cells at the distant site expressed PD-1. Therefore, blockade of PD-1 further enhanced tumor control at the distant site, leading to cure in 50% of the mice. These preclinical data provide the rationale for testing local injection of STINGa followed by agonistic anti-GITR and anti-PD-1 antibodies as immunotherapy for human lymphoma.

in vivo CD47 blockade
Xu, M. M., et al. (2017). "Dendritic Cells but Not Macrophages Sense Tumor Mitochondrial DNA for Cross-priming through Signal Regulatory Protein alpha Signaling" Immunity 47(2): 363-373 e365. PubMed

Inhibition of cytosolic DNA sensing represents a strategy that tumor cells use for immune evasion, but the underlying mechanisms are unclear. Here we have shown that CD47-signal regulatory protein alpha (SIRPalpha) axis dictates the fate of ingested DNA in DCs for immune evasion. Although macrophages were more potent in uptaking tumor DNA, increase of DNA sensing by blocking the interaction of SIRPalpha with CD47 preferentially occurred in dendritic cells (DCs) but not in macrophages. Mechanistically, CD47 blockade enabled the activation of NADPH oxidase NOX2 in DCs, which in turn inhibited phagosomal acidification and reduced the degradation of tumor mitochondrial DNA (mtDNA) in DCs. mtDNA was recognized by cyclic-GMP-AMP synthase (cGAS) in the DC cytosol, contributing to type I interferon (IFN) production and antitumor adaptive immunity. Thus, our findings have demonstrated how tumor cells inhibit innate sensing in DCs and suggested that the CD47-SIRPalpha axis is critical for DC-driven antitumor immunity.

in vivo CD47 blockade
Liu, X., et al. (2015). "CD47 blockade triggers T cell-mediated destruction of immunogenic tumors" Nat Med 21(10): 1209-1215. PubMed

Macrophage phagocytosis of tumor cells mediated by CD47-specific blocking antibodies has been proposed to be the major effector mechanism in xenograft models. Here, using syngeneic immunocompetent mouse tumor models, we reveal that the therapeutic effects of CD47 blockade depend on dendritic cell but not macrophage cross-priming of T cell responses. The therapeutic effects of anti-CD47 antibody therapy were abrogated in T cell-deficient mice. In addition, the antitumor effects of CD47 blockade required expression of the cytosolic DNA sensor STING, but neither MyD88 nor TRIF, in CD11c(+) cells, suggesting that cytosolic sensing of DNA from tumor cells is enhanced by anti-CD47 treatment, further bridging the innate and adaptive responses. Notably, the timing of administration of standard chemotherapy markedly impacted the induction of antitumor T cell responses by CD47 blockade. Together, our findings indicate that CD47 blockade drives T cell-mediated elimination of immunogenic tumors.

in vivo CD47 blockade
Shi, L., et al. (2015). "CD47 deficiency ameliorates autoimmune nephritis in Fas(lpr) mice by suppressing IgG autoantibody production" J Pathol 237(3): 285-295. PubMed

CD47, a self-recognition marker, plays an important role in both innate and adaptive immune responses. To explore the potential role of CD47 in activation of autoreactive T and B cells and the production of autoantibodies in autoimmune disease, especially systemic lupus erythematosus (SLE), we have generated CD47 knockout Fas(lpr) (CD47(-/-) -Fas(lpr) ) mice and examined histopathological changes in the kidneys, cumulative survival rates, proteinuria, extent of splenomegaly and autoantibodies, serum chemistry and immunological parameters. In comparison with Fas(lpr) mice, CD47(-/-) -Fas(lpr) mice exhibit a prolonged lifespan and delayed autoimmune nephritis, including glomerular cell proliferation, basement membrane thickening, acute tubular atrophy and vacuolization. CD47(-/-) -Fas(lpr) mice have lower levels of proteinuria, associated with reduced deposition of complement C3 and C1q, and IgG but not IgM in the glomeruli, compared to age-matched Fas(lpr) mice. Serum levels of antinuclear antibodies and anti-double-stranded DNA antibodies are significantly lower in CD47(-/-) -Fas(lpr) than in Fas(lpr) mice. CD47(-/-) -Fas(lpr) mice also display less pronounced splenomegaly than Fas(lpr) mice. The mechanistic studies further suggest that CD47 deficiency impairs the antigenic challenge-induced production of IgG but not IgM, and that this effect is associated with reduction of T follicular cells and impairment of germinal centre development in lymphoid tissues. In conclusion, our results demonstrate that CD47 deficiency ameliorates lupus nephritis in Fas(lpr) mice via suppression of IgG autoantibody production. Copyright (c) 2015 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

in vitro CD47 blockade, Immunofluorescence
Hsieh, C. P., et al. (2015). "Deficits in cerebellar granule cell development and social interactions in CD47 knockout mice" Dev Neurobiol 75(5): 463-484. PubMed

CD47 is involved in neurite differentiation in cultured neurons, but the function of CD47 in brain development is largely unknown. We determined that CD47 mRNA was robustly expressed in the developing cerebellum, especially in granule cells. CD47 protein was mainly expressed in the inner layer of the external granule layer (EGL), molecular layer, and internal granule layer (IGL), where granule cells individually become postmitotic and migrate, leading to neurite fasciculation. At postnatal day 8 (P8), CD47 knockout mice exhibited an increased number of proliferating granule cells in the EGL, whereas the CD47 agonist peptide 4N1K increased the number of postmitotic cells in primary granule cells. Knocking out the CD47 gene and anti-CD47 antibody impaired the radial migration of granule cells from the EGL to the IGL individually in mice and slice cultures. In primary granule cells, knocking out CD47 reduced the number of axonal collaterals and dendritic branches; by contrast, overexpressing CD47 or 4N1K treatment increased the axonal length and numbers of axonal collaterals and dendritic branches. Furthermore, the length of the fissure between Lobules VI and VII was decreased in CD47 knockout mice at P21 and at 14 wk after birth. Lastly, CD47 knockout mice exhibited increased social interaction at P21 and depressive-like behaviors at 10 wk after birth. Our study revealed that the cell adhesion molecule CD47 participates in multiple phases of granule cell development, including proliferation, migration, and neurite differentiation implying that aberrations of CD47 are risk factors that cause abnormalities in cerebellar development and atypical behaviors.

in vivo CD47 blockade
Maute, R. L., et al. (2015). "Engineering high-affinity PD-1 variants for optimized immunotherapy and immuno-PET imaging" Proc Natl Acad Sci U S A 112(47): E6506-6514. PubMed

Signaling through the immune checkpoint programmed cell death protein-1 (PD-1) enables tumor progression by dampening antitumor immune responses. Therapeutic blockade of the signaling axis between PD-1 and its ligand programmed cell death ligand-1 (PD-L1) with monoclonal antibodies has shown remarkable clinical success in the treatment of cancer. However, antibodies have inherent limitations that can curtail their efficacy in this setting, including poor tissue/tumor penetrance and detrimental Fc-effector functions that deplete immune cells. To determine if PD-1:PD-L1-directed immunotherapy could be improved with smaller, nonantibody therapeutics, we used directed evolution by yeast-surface display to engineer the PD-1 ectodomain as a high-affinity (110 pM) competitive antagonist of PD-L1. In contrast to anti-PD-L1 monoclonal antibodies, high-affinity PD-1 demonstrated superior tumor penetration without inducing depletion of peripheral effector T cells. Consistent with these advantages, in syngeneic CT26 tumor models, high-affinity PD-1 was effective in treating both small (50 mm(3)) and large tumors (150 mm(3)), whereas the activity of anti-PD-L1 antibodies was completely abrogated against large tumors. Furthermore, we found that high-affinity PD-1 could be radiolabeled and applied as a PET imaging tracer to efficiently distinguish between PD-L1-positive and PD-L1-negative tumors in living mice, providing an alternative to invasive biopsy and histological analysis. These results thus highlight the favorable pharmacology of small, nonantibody therapeutics for enhanced cancer immunotherapy and immune diagnostics.

in vitro CD47 blockade
Vermeer, D. W., et al. (2013). "Radiation-induced loss of cell surface CD47 enhances immune-mediated clearance of human papillomavirus-positive cancer" Int J Cancer 133(1): 120-129. PubMed

The increasing incidence of human papillomavirus (HPV) related oropharyngeal squamous cell carcinoma (OSSC) demands development of novel therapies. Despite presenting at a more advanced stage, HPV(+) oropharyngeal squamous cell carcinoma (OSCC) have a better prognosis than their HPV(-) counterparts. We have previously demonstrated that clearance of HPV(+) OSCC during treatment with radiation and chemotherapy requires an immune response which is likely responsible for the improved clinical outcomes. To further elucidate the mechanism of immune-mediated clearance, we asked whether radiation therapy induces tumor cell changes that allow the body to recognize and aid in tumor clearance. Here, we describe a radiation-induced change in tumor surface protein expression that is critical for immune-mediated clearance. Radiation therapy decreases surface expression of CD47, a self-marker. CD47 is frequently overexpressed in head and neck squamous cell carcinoma and radiation induces a decrease of CD47 in a dose-dependent manner. We show that both in vitro and in vivo tumor cell CD47 protein levels are restored over time after sublethal radiation exposure and that protein levels on adjacent, normal tissues remain unaffected. Furthermore, reduction of tumor cell CD47 increases phagocytosis of these cells by dendritic cells and leads to increased interferon gamma and granzyme production from mixed lymphocytes. Finally, decreasing tumor cell CD47 in combination with standard radiation and chemotherapy results in improved immune-mediated tumor clearance in vivo. These findings help define an important mechanism of radiation-related immune clearance and suggest that decreasing CD47 specifically on tumor cells may be a good therapeutic target for HPV related disease.

in vitro CD47 blockade
Majeti, R., et al. (2009). "CD47 is an adverse prognostic factor and therapeutic antibody target on human acute myeloid leukemia stem cells" Cell 138(2): 286-299. PubMed

Acute myeloid leukemia (AML) is organized as a cellular hierarchy initiated and maintained by a subset of self-renewing leukemia stem cells (LSC). We hypothesized that increased CD47 expression on human AML LSC contributes to pathogenesis by inhibiting their phagocytosis through the interaction of CD47 with an inhibitory receptor on phagocytes. We found that CD47 was more highly expressed on AML LSC than their normal counterparts, and that increased CD47 expression predicted worse overall survival in three independent cohorts of adult AML patients. Furthermore, blocking monoclonal antibodies directed against CD47 preferentially enabled phagocytosis of AML LSC and inhibited their engraftment in vivo. Finally, treatment of human AML LSC-engrafted mice with anti-CD47 antibody depleted AML and targeted AML LSC. In summary, increased CD47 expression is an independent, poor prognostic factor that can be targeted on human AML stem cells with blocking monoclonal antibodies capable of enabling phagocytosis of LSC.

in vivo CD47 blockade
Chang, H. P., et al. (2001). "Functional blocking of integrin-associated protein impairs memory retention and decreases glutamate release from the hippocampus" Neuroscience 102(2): 289-296. PubMed

We have previously demonstrated that integrin-associated protein is involved in memory consolidation of one-way inhibitory avoidance learning in rats and mice. In the present study, we examined the effects of functional blocking of integrin-associated protein on memory retention, long-term potentiation and glutamate release in mice as well as on cell attachment to extracellular matrix protein in primary cultures. The results indicated that integrin-associated protein monoclonal antibody miap301, when directly injected into the dentate gyrus of the hippocampus at moderate doses, significantly impairs memory retention in mice in the same one-way inhibitory avoidance task and decreases the amplitude of tetanic stimulation-induced long-term potentiation in dentate gyrus neurons. At a dose that effectively impairs both memory retention and long-term potentiation, integrin-associated protein monoclonal antibody also significantly blocks potassium chloride-induced glutamate release from the hippocampus in vivo. Results from western blot confirmed the presence of integrin-associated protein at the synaptic area. Cell adhesion experiments further revealed that integrin-associated protein monoclonal antibody markedly inhibits granular cell attachment to thrombospondin, the extracellular matrix protein known to bind integrin-associated protein, but not to collagen and laminin, the extracellular matrix proteins known to bind integrin. From these results we suggest that integrin-associated protein monoclonal antibody may impair synaptic plasticity and behavioral plasticity in mice through blockade of granular cell attachment to extracellular matrix protein and the subsequent signal transduction, and through inhibition of glutamate release from the hippocampus.

    • Mus musculus (House mouse)
    • ,
    • Cancer Research
    • ,
    • Genetics
    • ,
    • Immunology and Microbiology
    Chromosomal instability induced in cancer can enhance macrophage-initiated immune responses that include anti-tumor IgG.

    In eLife on 28 May 2024 by Hayes, B., Wang, M., et al.

    PubMed

    Solid tumors generally exhibit chromosome copy number variation, which is typically caused by chromosomal instability (CIN) in mitosis. The resulting aneuploidy can drive evolution and associates with poor prognosis in various cancer types as well as poor response to T-cell checkpoint blockade in melanoma. Macrophages and the SIRPα-CD47 checkpoint are understudied in such contexts. Here, CIN is induced in poorly immunogenic B16F10 mouse melanoma cells using spindle assembly checkpoint MPS1 inhibitors that generate persistent micronuclei and diverse aneuploidy while skewing macrophages toward a tumoricidal 'M1-like' phenotype based on markers and short-term anti-tumor studies. Mice bearing CIN-afflicted tumors with wild-type CD47 levels succumb similar to controls, but long-term survival is maximized by SIRPα blockade on adoptively transferred myeloid cells plus anti-tumor monoclonal IgG. Such cells are the initiating effector cells, and survivors make de novo anti-cancer IgG that not only promote phagocytosis of CD47-null cells but also suppress tumor growth. CIN does not affect the IgG response, but pairing CIN with maximal macrophage anti-cancer activity increases durable cures that possess a vaccination-like response against recurrence. © 2023, Hayes et al.

    • Mus musculus (House mouse)
    • ,
    • Immunology and Microbiology
    Airway epithelial CD47 plays a critical role in inducing influenza virus-mediated bacterial super-infection.

    In Nature Communications on 30 April 2024 by Moon, S., Han, S., et al.

    PubMed

    Respiratory viral infection increases host susceptibility to secondary bacterial infections, yet the precise dynamics within airway epithelia remain elusive. Here, we elucidate the pivotal role of CD47 in the airway epithelium during bacterial super-infection. We demonstrated that upon influenza virus infection, CD47 expression was upregulated and localized on the apical surface of ciliated cells within primary human nasal or bronchial epithelial cells. This induced CD47 exposure provided attachment sites for Staphylococcus aureus, thereby compromising the epithelial barrier integrity. Through bacterial adhesion assays and in vitro pull-down assays, we identified fibronectin-binding proteins (FnBP) of S. aureus as a key component that binds to CD47. Furthermore, we found that ciliated cell-specific CD47 deficiency or neutralizing antibody-mediated CD47 inactivation enhanced in vivo survival rates. These findings suggest that interfering with the interaction between airway epithelial CD47 and pathogenic bacterial FnBP holds promise for alleviating the adverse effects of super-infection. © 2024. The Author(s).

    • Cancer Research
    • ,
    • Immunology and Microbiology
    IGF2BP3 Enhances the Growth of Hepatocellular Carcinoma Tumors by Regulating the Properties of Macrophages and CD8+ T Cells in the Tumor Microenvironment.

    In Journal of Clinical and Translational Hepatology on 28 November 2023 by Ma, L., Jiang, J., et al.

    PubMed

    Overexpression of IGF2BP3 is associated with the prognosis of hepatocellular carcinoma (HCC). However, its role in regulating tumor immune microenvironment (TME) is not well characterized. Here, we investigated the effects of IGF2BP3 on macrophages and CD8+ T cells within the TME of HCC. The relationship between IGF2BP3 and immune cell infiltration was analyzed using online bioinformatics tools. Knockout of IGF2BP3 in mouse hepatoma cell line Hepa1-6 was established using CRISPR/Cas9 technology. In vitro cell coculture and subcutaneously implanted hepatoma mice model were used to explore the effects of IGF2BP3 on immune cells. Expression of CCL5 or transforming growth factor beta 1 (TGF-β1) was detected with quantitative real-time polymerase chain reaction, western blotting, and enzyme-linked immunosorbent assay. The binding of IGF2BP3 and its target RNA was verified by trimolecular fluorescence complementation system and RNA immunoprecipitation followed by quantitative or semiquantitative polymerase chain reaction. IGF2BP3 expression was elevated in HCC and was positively correlated with macrophage infiltration. Patients with higher IGF2BP3 expression and lower macrophage infiltration had a better survival rate. We found that IGF2BP3 could bind to the mRNA of CCL5 or TGF-β1, increasing their expression, and inducing macrophage infiltration and M2 polarization while inhibiting the activation of CD8+ T cells. Furthermore, inhibition of IGF2BP3 combined with anti-CD47 antibody treatment significantly suppressed the growth of hepatoma in Hepa1-6 xenograft tumor mice. IGF2BP3 promoted the infiltration and M2-polarization of macrophages and suppressed CD8+ T activation by enhancing CCL5 and TGF-β1 expression, which facilitated the progression of Hepa1-6 xenograft tumor. © 2023 Authors.

    • Cancer Research
    • ,
    • In Vivo
    • ,
    • Mus musculus (House mouse)
    THBS1-producing tumor-infiltrating monocyte-like cells contribute to immunosuppression and metastasis in colorectal cancer.

    In Nature Communications on 25 September 2023 by Omatsu, M., Nakanishi, Y., et al.

    PubMed

    Mesenchymal activation, characterized by dense stromal infiltration of immune and mesenchymal cells, fuels the aggressiveness of colorectal cancers (CRC), driving progression and metastasis. Targetable molecules in the tumor microenvironment (TME) need to be identified to improve the outcome in CRC patients with this aggressive phenotype. This study reports a positive link between high thrombospondin-1 (THBS1) expression and mesenchymal characteristics, immunosuppression, and unfavorable CRC prognosis. Bone marrow-derived monocyte-like cells recruited by CXCL12 are the primary source of THBS1, which contributes to the development of metastasis by inducing cytotoxic T-cell exhaustion and impairing vascularization. Furthermore, in orthotopically generated CRC models in male mice, THBS1 loss in the TME renders tumors partially sensitive to immune checkpoint inhibitors and anti-cancer drugs. Our study establishes THBS1 as a potential biomarker for identifying mesenchymal CRC and as a critical suppressor of antitumor immunity that contributes to the progression of this malignancy with a poor prognosis. © 2023. Springer Nature Limited.

    • Mus musculus (House mouse)
    • ,
    • Biochemistry and Molecular biology
    Blockade of CD47 function attenuates restenosis by promoting smooth muscle cell efferocytosis and inhibiting their migration and proliferation.

    In The Journal of Biological Chemistry on 1 April 2023 by Govatati, S., Pichavaram, P., et al.

    PubMed

    Cluster of differentiation 47 (CD47) plays an important role in the pathophysiology of various diseases including atherosclerosis but its role in neointimal hyperplasia which contributes to restenosis has not been studied. Using molecular approaches in combination with a mouse vascular endothelial denudation model, we studied the role of CD47 in injury-induced neointimal hyperplasia. We determined that thrombin-induced CD47 expression both in human aortic smooth muscle cells (HASMCs) and mouse aortic smooth muscle cells. In exploring the mechanisms, we found that the protease-activated receptor 1-Gα protein q/11 (Gαq/11)-phospholipase Cβ3-nuclear factor of activated T cells c1 signaling axis regulates thrombin-induced CD47 expression in HASMCs. Depletion of CD47 levels using its siRNA or interference of its function by its blocking antibody (bAb) blunted thrombin-induced migration and proliferation of HASMCs and mouse aortic smooth muscle cells. In addition, we found that thrombin-induced HASMC migration requires CD47 interaction with integrin β3. On the other hand, thrombin-induced HASMC proliferation was dependent on CD47's role in nuclear export and degradation of cyclin-dependent kinase-interacting protein 1. In addition, suppression of CD47 function by its bAb rescued HASMC efferocytosis from inhibition by thrombin. We also found that vascular injury induces CD47 expression in intimal SMCs and that inhibition of CD47 function by its bAb, while alleviating injury-induced inhibition of SMC efferocytosis, attenuated SMC migration, and proliferation resulting in reduced neointima formation. Thus, these findings reveal a pathological role for CD47 in neointimal hyperplasia. Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.

    • Cancer Research
    • ,
    • Immunology and Microbiology
    • ,
    • Mus musculus (House mouse)
    Modular-designed engineered bacteria for precision tumor immunotherapy via spatiotemporal manipulation by magnetic field.

    In Nature Communications on 23 March 2023 by Ma, X., Liang, X., et al.

    PubMed

    Micro-nano biorobots based on bacteria have demonstrated great potential for tumor diagnosis and treatment. The bacterial gene expression and drug release should be spatiotemporally controlled to avoid drug release in healthy tissues and undesired toxicity. Herein, we describe an alternating magnetic field-manipulated tumor-homing bacteria developed by genetically modifying engineered Escherichia coli with Fe3O4@lipid nanocomposites. After accumulating in orthotopic colon tumors in female mice, the paramagnetic Fe3O4 nanoparticles enable the engineered bacteria to receive and convert magnetic signals into heat, thereby initiating expression of lysis proteins under the control of a heat-sensitive promoter. The engineered bacteria then lyse, releasing its anti-CD47 nanobody cargo, that is pre-expressed and within the bacteria. The robust immunogenicity of bacterial lysate cooperates with anti-CD47 nanobody to activate both innate and adaptive immune responses, generating robust antitumor effects against not only orthotopic colon tumors but also distal tumors in female mice. The magnetically engineered bacteria also enable the constant magnetic field-controlled motion for enhanced tumor targeting and increased therapeutic efficacy. Thus, the gene expression and drug release behavior of tumor-homing bacteria can be spatiotemporally manipulated in vivo by a magnetic field, achieving tumor-specific CD47 blockage and precision tumor immunotherapy. © 2023. The Author(s).

    • Immunology and Microbiology
    • ,
    • Mus musculus (House mouse)
    The CIt protocol: A blueprint to potentiate the immunogenicity of immunoproteasome-reprogrammed mesenchymal stromal cells.

    In IScience on 22 December 2022 by Bikorimana, J. P., El-Hachem, N., et al.

    PubMed

    Immunoproteasome-reprogrammed mesenchymal stromal cells (IRMs) can surpass dendritic cells at eliciting tumor-specific immunity. However, the current IRM vaccination regimen remains clinically unsuitable due to the relatively high dose of IRMs needed. Since the administration of a lower IRM dose triggers a feeble anti-tumoral response, we aimed to combine this vaccination regimen with different modalities to fine-tune the potency of the vaccine. In a nutshell, we found that the co-administration of IRMs and interleukin-12 accentuates the anti-tumoral response, whereas the cross-presentation potency of IRMs is enhanced via intracellular succinate build-up, delayed endosomal maturation, and increased endosome-to-cytosol plasticity. Stimulating phagocyte-mediated cancer efferocytosis by blocking the CD47-SIRPα axis was also found to enhance IRM vaccine outcomes. Upon designing a single protocol combining the abovementioned strategies, 60% of treated animals exhibited a complete response. Altogether, this is the first IRM-based vaccination study, optimized to simultaneously target three vaccine-related pitfalls: T-cell response, antigen cross-presentation, and cancer phagocytosis. © 2022 The Author(s).

    • Cancer Research
    • ,
    • Mus musculus (House mouse)
    PARP-inhibition reprograms macrophages toward an anti-tumor phenotype.

    In Cell Reports on 11 October 2022 by Wang, L., Wang, D., et al.

    PubMed

    Poly(ADP)ribosylation inhibitors (PARPis) are toxic to cancer cells with homologous recombination (HR) deficiency but not to HR-proficient cells in the tumor microenvironment (TME), including tumor-associated macrophages (TAMs). As TAMs can promote or inhibit tumor growth, we set out to examine the effects of PARP inhibition on TAMs in BRCA1-related breast cancer (BC). The PARPi olaparib causes reprogramming of TAMs toward higher cytotoxicity and phagocytosis. A PARPi-related surge in NAD+ increases glycolysis, blunts oxidative phosphorylation, and induces reverse mitochondrial electron transport (RET) with an increase in reactive oxygen species (ROS) and transcriptional reprogramming. This reprogramming occurs in the absence or presence of PARP1 or PARP2 and is partially recapitulated by addition of NAD derivative methyl-nicotinamide (MNA). In vivo and ex vivo, the effect of olaparib on TAMs contributes to the anti-tumor efficacy of the PARPi. In vivo blockade of the "don't-eat-me signal" with CD47 antibodies in combination with olaparib improves outcomes in a BRCA1-related BC model. Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.

    • Mus musculus (House mouse)
    • ,
    • Cancer Research
    • ,
    • Immunology and Microbiology
    Self-assembled traditional Chinese nanomedicine modulating tumor immunosuppressive microenvironment for colorectal cancer immunotherapy.

    In Theranostics on 29 September 2022 by Mao, Q., Min, J., et al.

    PubMed

    Colorectal cancer (CRC), mostly categorized as a low immunogenic microsatellite-stable phenotype bearing complex immunosuppressive tumor microenvironment (TME), is highly resistant to immunotherapy. Seeking safe and efficient alternatives aimed at modulating tumor immunosuppressive TME to improve outcome of CRC is highly anticipated yet remains challenging. Methods: Enlightened from the drug complementary art in traditional Chinese medicine, we designed a self-assembled nanomedicine (termed LNT-UA) by the natural active ingredients of ursolic acid (UA) and lentinan (LNT) through a simple nano-precipitation method, without any extra carriers, for CRC immunotherapy. Results: UA induces immunogenic cell death (ICD), while LNT further promotes dendritic cell (DC) maturation and repolarizes tumor-associated macrophage (TAM) from a protumorigenic M2 to an antitumor M1 phenotype. Co-delivery of UA and LNT by LNT-UA effectively reshapes the immunosuppressive TME and mobilizes innate and adaptive immunity to inhibit tumor progression in the CT26 CRC tumor model. Following the principle of integrative theoretical system of traditional Chinese medicine (TCM) on overall regulation, the further combination of LNT-UA and anti-CD47 antibody (αCD47) would reinforce the antitumor immunity by promoting phagocytosis of dying tumor cells and tumor-associated antigens (TAAs), leading to effective suppression of both primary and distant tumor growth with 2.2-fold longer of median survival time in the bilateral tumor model. Most notably, this combination effect is also observed in the spontaneous CRC model induced by chemical carcinogens, with much less and smaller size of tumor nodules after sequential administration of LNT-UA and αCD47 through gavage and intraperitoneal injection, respectively. Conclusions: This study provides a promising self-assembled traditional Chinese nanomedicine to improve immunotherapy for CRC, which might be applicable for future clinical translation. © The author(s).

    • Cancer Research
    Disulfiram/Copper Induces Immunogenic Cell Death and Enhances CD47 Blockade in Hepatocellular Carcinoma.

    In Cancers on 28 September 2022 by Gao, X., Huang, H., et al.

    PubMed

    Some chemotherapeutic agents have been found to enhance antitumor immunity by inducing immunogenic cell death (ICD). The combination of disulfiram (DSF) and copper (Cu) has demonstrated anti-tumor effects in a range of malignancies including hepatocellular carcinoma (HCC). However, the potential of DSF/Cu as an ICD inducer and whether it can enhance the efficacy of the immune checkpoint blockade in HCC remains unknown. Here, we showed that DSF/Cu-treated HCC cells exhibited characteristics of ICD in vitro, such as calreticulin (CRT) exposure, ATP secretion, and high mobility group box 1 (HMGB1) release. DSF/Cu-treated HCC cells elicited significant immune memory in a vaccination assay. DSF/Cu treatment promoted dendritic cell activation and maturation. The combination of DSF/Cu and CD47 blockade further facilitated DC maturation and subsequently enhanced CD8+ T cell cytotoxicity. Mechanically, DSF/Cu promoted the nuclear accumulation and aggregation of nuclear protein localization protein 4 (NPL4) to inhibit the ubiquitin-proteasome system; thus, inducing endoplasmic reticulum (ER) stress. The inhibition of NPL4 induced ICD-associated damage-associated molecular patterns. Collectively, our findings demonstrated that DSF/Cu-induced ICD-mediated immune activation in HCC enhanced the efficacy of CD47 blockade.

    • Cancer Research
    • ,
    • Immunology and Microbiology
    • ,
    • Mus musculus (House mouse)
    Reactive oxygen species-responsive and Raman-traceable hydrogel combining photodynamic and immune therapy for postsurgical cancer treatment.

    In Nature Communications on 5 August 2022 by Zhang, Y., Tian, S., et al.

    PubMed

    Combining immune checkpoint blockade (ICB) therapy with photodynamic therapy (PDT) holds great potential in treating immunologically "cold" tumors, but photo-generated reactive oxygen species (ROS) can inevitably damage co-administered ICB antibodies, hence hampering the therapeutic outcome. Here we create a ROS-responsive hydrogel to realize the sustained co-delivery of photosensitizers and ICB antibodies. During PDT, the hydrogel skeleton poly(deca-4,6-diynedioic acid) (PDDA) protects ICB antibodies by scavenging the harmful ROS, and at the same time, triggers the gradual degradation of the hydrogel to release the drugs in a controlled manner. More interestingly, we can visualize the ROS-responsive hydrogel degradation by Raman imaging, given the ultrastrong and degradation-correlative Raman signal of PDDA in the cellular silent window. A single administration of the hydrogel not only completely inhibits the long-term postoperative recurrence and metastasis of 4T1-tumor-bearing mice, but also effectively restrains the growth of re-challenged tumors. The PDDA-based ROS-responsive hydrogel herein paves a promising way for the durable synergy of PDT and ICB therapy. © 2022. The Author(s).

    • Cancer Research
    • ,
    • Immunology and Microbiology
    • ,
    • Mus musculus (House mouse)
    Cooperative phagocytosis underlies macrophage immunotherapy of solid tumours and initiates a broad anti-tumour IgG response

    Preprint on BioRxiv : the Preprint Server for Biology on 2 January 2022 by Andrechak, J. C., Dooling, L. J., et al.

    PubMed

    Macrophages are abundant in solid tumours and typically associate with poor prognosis, but macrophage clusters in tumour nests have also been reported as beneficial even though dispersed macrophages would have more contacts with cancer cells. Here, by maximizing both phagocytic activity and macrophage numbers, we discover cooperative phagocytosis by low entropy clusters in rapidly growing engineered immuno-tumouroids. The results fit the calculus of proliferation-versus-engulfment, and rheological measurements and molecular perturbations provide a basis for understanding phagocytic disruption of a tumour’s cohesive forces in soft cellular phases. The perturbations underscore the utility of suppressing a macrophage checkpoint in combination with an otherwise ineffective tumour-opsonizing monoclonal antibody, and the approach translates in vivo to tumour elimination that durably protects mice from re-challenge and metastasis. Adoptive transfer of engineered macrophages increases the fraction of mice that eliminate tumours and potentially overcomes checkpoint blockade challenges in solid tumours like insufficient permeation of blocking antibodies and on-target, off-tumour binding. Finally, anti-cancer IgG induced in vivo are tumour-specific but multi-epitope and contribute to a phagocytic feedback that drives macrophage clustering in vitro . Given that solid tumours remain challenging for immunotherapies, durable anti-tumour responses here illustrate unexpected advantages in maximizing net phagocytic activity.

    • WB
    • ,
    • Mus musculus (House mouse)
    • ,
    • Immunology and Microbiology
    YAP-Dependent Induction of CD47-Enriched Extracellular Vesicles Inhibits Dendritic Cell Activation and Ameliorates Hepatic Ischemia-Reperfusion Injury.

    In Oxidative Medicine and Cellular Longevity on 10 July 2021 by Yuan, Z., Ye, L., et al.

    PubMed

    Hepatic ischemia-reperfusion injury (IRI) is the most common cause of liver damage leading to surgical failures in hepatectomy and liver transplantation. Extensive inflammatory reactions and oxidative responses are reported to be the major processes exacerbating IRI. The involvement of Yes-associated protein (YAP) in either process has been suggested, but the role and mechanism of YAP in IRI remain unclear. In this study, we constructed hepatocyte-specific YAP knockout (YAP-HKO) mice and induced a hepatic IRI model. Surprisingly, the amount of serum EVs decreased in YAP-HKO compared to WT mice during hepatic IRI. Then, we found that the activation of YAP increased EV secretion through F-actin by increasing membrane formation, while inhibiting the fusion of multivesicular body (MVB) and lysosomes in hepatocytes. Further, to explore the essential elements of YAP-induced EVs, we applied mass spectrometry and noticed CD47 was among the top targets highly expressed on hepatocyte-derived EVs. Thus, we enriched CD47+ EVs by microbeads and applied the isolated CD47+ EVs on IRI mice. We found ameliorated IRI symptoms after CD47+ EV treatment in these mice, and CD47+ EVs bound to CD172α on the surface of dendritic cells (DCs), which inhibited DC activation and the cascade of inflammatory responses. Our data showed that CD47-enriched EVs were released in a YAP-dependent manner by hepatocytes, which could inhibit DC activation and contribute to the amelioration of hepatic IRI. CD47+ EVs could be a potential strategy for treating hepatic IRI. Copyright © 2021 Zenan Yuan et al.

    • ICC-IF
    • ,
    • Biochemistry and Molecular biology
    CXCR4 engagement triggers CD47 internalization and antitumor immunization in a mouse model of mesothelioma.

    In EMBO Molecular Medicine on 7 June 2021 by Mezzapelle, R., De Marchis, F., et al.

    PubMed

    Boosting antitumor immunity has emerged as a powerful strategy in cancer treatment. While releasing T-cell brakes has received most attention, tumor recognition by T cells is a pre-requisite. Radiotherapy and certain cytotoxic drugs induce the release of damage-associated molecular patterns, which promote tumor antigen cross-presentation and T-cell priming. Antibodies against the "do not eat me" signal CD47 cause macrophage phagocytosis of live tumor cells and drive the emergence of antitumor T cells. Here we show that CXCR4 activation, so far associated only with tumor progression and metastasis, also flags tumor cells to immune recognition. Both CXCL12, the natural CXCR4 ligand, and BoxA, a fragment of HMGB1, promote the release of DAMPs and the internalization of CD47, leading to protective antitumor immunity. We designate as Immunogenic Surrender the process by which CXCR4 turns in tumor cells to macrophages, thereby subjecting a rapidly growing tissue to immunological scrutiny. Importantly, while CXCL12 promotes tumor cell proliferation, BoxA reduces it, and might be exploited for the treatment of malignant mesothelioma and a variety of other tumors. © 2021 The Authors. Published under the terms of the CC BY 4.0 license.

    • Cancer Research
    • ,
    • Immunology and Microbiology
    Selective SIRPα blockade reverses tumor T cell exclusion and overcomes cancer immunotherapy resistance.

    In The Journal of Clinical Investigation on 2 November 2020 by Gauttier, V., Pengam, S., et al.

    PubMed

    T cell exclusion causes resistance to cancer immunotherapies via immune checkpoint blockade (ICB). Myeloid cells contribute to resistance by expressing signal regulatory protein-α (SIRPα), an inhibitory membrane receptor that interacts with ubiquitous receptor CD47 to control macrophage phagocytosis in the tumor microenvironment. Although CD47/SIRPα-targeting drugs have been assessed in preclinical models, the therapeutic benefit of selectively blocking SIRPα, and not SIRPγ/CD47, in humans remains unknown. We report a potent synergy between selective SIRPα blockade and ICB in increasing memory T cell responses and reverting exclusion in syngeneic and orthotopic tumor models. Selective SIRPα blockade stimulated tumor nest T cell recruitment by restoring murine and human macrophage chemokine secretion and increased anti-tumor T cell responses by promoting tumor-antigen crosspresentation by dendritic cells. However, nonselective SIRPα/SIRPγ blockade targeting CD47 impaired human T cell activation, proliferation, and endothelial transmigration. Selective SIRPα inhibition opens an attractive avenue to overcoming ICB resistance in patients with elevated myeloid cell infiltration in solid tumors.

    • Cancer Research
    • ,
    • Immunology and Microbiology
    CD47/SIRPα blocking peptide identification and synergistic effect with irradiation for cancer immunotherapy.

    In Journal for Immunotherapy of Cancer on 1 October 2020 by Wang, H., Sun, Y., et al.

    PubMed

    Immunotherapy has achieved remarkable advances via a variety of strategies against tumor cells that evade immune surveillance. As important innate immune cells, macrophages play important roles in maintaining homeostasis, preventing pathogen invasion, resisting tumor cells and promoting adaptive immune response. CD47 is found to be overexpressed on tumor cells and act as a don't eat me' signal, which contributes to immune evasion. Macrophages mediated phagocytosis via blockade CD47/SIRPα (signal regulatory protein alpha) interaction was proved to induce effective antitumor immune response. A novel peptide pep-20, specifically targeting CD47 and blocking CD47/SIRPα interaction, was identified via high-throughput phage display library bio-panning. The capability to enhance the macrophage-mediated phagocytosis activities and antitumor effects of pep-20 were investigated. The mechanism of pep-20 to induce T-cell response was explored by ex vivo analysis and confirmed via macrophage depleting strategy. The structure-activity relationship and D-amino acid substitution of pep-20 were also studied. The antitumor effects and mechanism of a proteolysis resistant D-amino acid derivate pep-20-D12 combined with irradiation (IR) were also investigated. Pep-20 showed remarkable enhancement of macrophage-mediated phagocytosis to both solid and hematologic tumor cells in vitro, and inhibited tumor growth in immune-competent tumor-bearing mice. Furthermore, pep-20 promoted macrophages to mobilize the antitumor T-cell response with minimal toxicity. Furthermore, systemic administration of the derivate pep-20-D12 showed robust synergistic antitumor efficacy in combination with IR. In summary, these results demonstrated that CD47/SIRPα blocking peptides, pep-20 and its derivate, could serve as promising candidates to promote macrophages-mediated phagocytosis and immune response in cancer immunotherapy. © Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY. Published by BMJ.

    • Mus musculus (House mouse)
    • ,
    • Cancer Research
    • ,
    • Immunology and Microbiology
    Targeting cluster of differentiation 47 improves the efficacy of anti-cytotoxic T-lymphocyte associated protein 4 treatment via antigen presentation enhancement in pancreatic ductal adenocarcinoma.

    In Experimental and Therapeutic Medicine on 1 October 2020 by Song, X., Lu, Z., et al.

    PubMed

    Treatment with cluster of differentiation 47 (CD47) monoclonal antibody has exhibited promising antitumor effects in various preclinical cancer models. However, its role in pancreatic ductal adenocarcinoma (PDAC) remains unclear. In the present study, the CD47 expression level was measured in PDAC patient samples. The effects of CD47 on antigen presentation and anti-tumor immunity were evaluated using phagocytotic assays and animal models. The results indicated that CD47 was overexpressed in the tumor tissue of PDAC patients compared with that in normal adjacent tissues. In the human samples, antigen-presenting cells (macrophages and dendritic cells) in tumors with high CD47 expression demonstrated low CD80 and CD86 expression levels. In an in vitro co-culture tumor cell system, CD47 overexpression was observed to inhibit the function of phagocytic cells. Furthermore, in a PDAC mouse model, CD47 overexpression was indicated to reduce antigen-presenting cell tumor infiltration and T-cell priming in tumor-draining lymph nodes. Anti-CD47 treatment appeared to enhance the efficacy of the approved immune checkpoint blockade agent anti-cytotoxic T-lymphocyte associated protein 4 (anti-CTLA4) in suppressing PDAC development in a mouse model. Therefore, it was concluded that CD47 overexpression suppressed antigen presentation and T-cell priming in PDAC. Anti-CD47 treatment may enhance the efficacy of anti-CTLA4 therapy and may therefore be a potential strategy for the treatment of PDAC patients in the future. Copyright © 2020, Spandidos Publications.

    • Cancer Research
    • ,
    • Immunology and Microbiology
    Hybrid cellular membrane nanovesicles amplify macrophage immune responses against cancer recurrence and metastasis.

    In Nature Communications on 30 September 2020 by Rao, L., Wu, L., et al.

    PubMed

    Effectively activating macrophages against cancer is promising but challenging. In particular, cancer cells express CD47, a 'don't eat me' signal that interacts with signal regulatory protein alpha (SIRPα) on macrophages to prevent phagocytosis. Also, cancer cells secrete stimulating factors, which polarize tumor-associated macrophages from an antitumor M1 phenotype to a tumorigenic M2 phenotype. Here, we report that hybrid cell membrane nanovesicles (known as hNVs) displaying SIRPα variants with significantly increased affinity to CD47 and containing M2-to-M1 repolarization signals can disable both mechanisms. The hNVs block CD47-SIRPα signaling axis while promoting M2-to-M1 repolarization within tumor microenvironment, significantly preventing both local recurrence and distant metastasis in malignant melanoma models. Furthermore, by loading a stimulator of interferon genes (STING) agonist, hNVs lead to potent tumor inhibition in a poorly immunogenic triple negative breast cancer model. hNVs are safe, stable, drug loadable, and suitable for genetic editing. These properties, combined with the capabilities inherited from source cells, make hNVs an attractive immunotherapy.

    • Cancer Research
    • ,
    • Immunology and Microbiology
    Restoration of miR-340 controls pancreatic cancer cell CD47 expression to promote macrophage phagocytosis and enhance antitumor immunity.

    In Journal for Immunotherapy of Cancer on 1 June 2020 by Xi, Q., Zhang, J., et al.

    PubMed

    Immune checkpoint blockade has emerged as a potential cancer immunotherapy. The "don't eat me" signal CD47 in cancer cells binds signal regulatory protein-α on macrophages and prevents their phagocytosis. The role of miR-340 in pancreatic ductal adenocarcinoma (PDAC), especially in tumor immunity, has not been explored. Here, we examined the clinical and biological relevance of miR-340 and the molecular pathways regulated by miR-340 in PDAC. CD47 and miR-340 expression and the relationship with cancer patient survival were analyzed by bioinformatics. The mechanism of miR-340 action was explored through bioinformatics, luciferase reporter, qRT-PCR and western blot analyses. The effects of miR-340 on cancer cells were analyzed in terms of apoptosis, proliferation, migration and phagocytosis by macrophages. In vivo tumorigenesis was studied in orthotopic and subcutaneous models, and immune cells from the peripheral and tumor immune microenvironments were analyzed by flow cytometry. Depletion of macrophages was used to verify the role of macrophages in impacting the function of miR-340 in tumor progression. miR-340 directly regulates and inversely correlates with CD47, and it predicts patient survival in PDAC. The restoration of miR-340 expression in pancreatic cancer cells was sufficient to downregulate CD47 and promote phagocytosis of macrophages, further inhibiting tumor growth. The overexpression of miR-340 promoted macrophages to become M1-like phenotype polarized in peripheral and tumor immune microenvironments and increased T cells, especially CD8+ T cells, contributing to the antitumor effect of miR-340. miR-340 is a key regulator of phagocytosis and antitumor immunity, and it could offer a new opportunity for immunotherapy for PDAC. © Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

    • Immunology and Microbiology
    Intratumoral accumulation of gut microbiota facilitates CD47-based immunotherapy via STING signaling.

    In The Journal of Experimental Medicine on 4 May 2020 by Shi, Y., Zheng, W., et al.

    PubMed

    Most studies focus on how intestinal microbiota influence cancer immunotherapy through activating gut immunity. However, immunotherapies related to innate responses such as CD47 blockade rely on the rapid immune responses within the tumor microenvironment. Using one defined anaerobic gut microbiota to track whether microbiota interact with host immunity, we observed that Bifidobacterium facilitates local anti-CD47 immunotherapy on tumor tissues through the capacity to accumulate within the tumor microenvironment. Systemic administration of Bifidobacterium leads to its accumulation within the tumor and converts the nonresponder mice into responders to anti-CD47 immunotherapy in a stimulator of interferon genes (STING)- and interferon-dependent fashion. Local delivery of Bifidobacterium potently stimulates STING signaling and increases cross-priming of dendritic cells after anti-CD47 treatment. Our study identifies the mechanism by which gut microbiota preferentially colonize in tumor sites and facilitate immunotherapy via STING signaling. © 2020 Shi et al.

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