CD47, also known as integrin-associated protein (IAP), is an ubiquitously expressed 50 kD cell membrane glycoprotein. This article reviews that as an integrin-associated molecule, CD47 regulates a series of integrin-dependent cell functions; CD47 regulates cell adhesiveness, migration and activation and platelet aggregation through binding to thrombospondins; CD7 is the extracellular ligand for human signal-regulatory proteins, thus it causes negative regulatory effect; CD47 induces costimulatory signals on activation of T cell, T cell apoptosis and T cell anergy and enhances the efficiency of TCR signaling; CD47 is a member of Rh antigen complex. CD47 is involved in stroma-supported erythropoiesis. This review also discussed that CD47 as a marker on red blood cells, associated with haemolysis, which provides a new way to recognize, diagnose, and treat diseases.
Animals ; Antigens, CD ; physiology ; CD47 Antigen ; Carrier Proteins ; physiology ; Humans

CD47 is a ubiquitously expressed transmembrane glycoprotein on surface of many cells. Through its interaction with integrin, signal regulatory protein alpha (SIRPα) and thrombin sensitive protein-1 (TSP-1), it plays important roles in various immunological processes including inflammatory response, immune response and tumor immunity. Recently, it has been found that CD47 interacts with SIRPα expressed on phagocytic cells, which transfers a negative signal when being activated. By the mechanisms described above, CD47-SIRPα signal complex is involved in the pathogenesis of hematological diseases and might provide some informations for the therapy of patients. This review focuses on the structure and immunoregulatory functions of CD47, the mechanism of CD47 in tumor therapy, the CD47 and hematologic malignancies including acute leukemia, B-cell lymphoma and multiple myeloma, as well as CD47 and hematopoietic stem cell transplantation.
Animals ; Antigens, Differentiation ; metabolism ; CD47 Antigen ; metabolism ; Hematologic Neoplasms ; metabolism ; Humans ; Receptors, Immunologic ; metabolism ; Signal Transduction

To investigate the influence and mechanisms of CD47 engagement by its soluble mAb B6H12 on the maturation and function of cultured dendritic cells (DCs), monocyte-derived DCs were propagated in granulocyte-macrophage colony stimulating factor (GM-CSF) combined with lipopolysaccharide (LPS) and interleukin (IL)-4, in the presence or absence of soluble anti-CD47 monoclonal antibodies (anti-CD47 mAbs, B6H12). The characteristic morphology of DCs was identified by using the transmission electron microscopy. Flow cytometry was used to detect the cell surface phenotypes. The concentration of IL-12 P70 in supernatant was measured by ELISA. The antigen-presenting functions of DCs were determined in one-way mixed leukocyte reaction by BrdU-ELISA. Electrophoretic mobility shift assay (EMSA) was applied to examine the activity of NF-kappaB. The results indicated that the anti-CD47 mAbs markedly suppressed the expression of CD80, CD86, CD83, CD1a and HLA-DR on the surface of DCs (P < 0.05). The data of the mixed leukocyte reaction and IL-12 P70 production were consistent with the results by flow cytometry (P < 0.01). Pre-exposure to B6H12 mAb during the development of DCs resulted in a dramatic depletion of the DNA binding activity of NF-kappaB toward nucleus protein. Moreover, such an inhibition effect seemed to be dose dependent. In conclusion, the soluble mAb B6H12 inhibits the expression of the costimulatory molecules and MHCII molecules on the DCs. The antigen-presenting function of DCs was also impaired by B6H12. And these modulations are closely related with the depletive DNA binding activity of NF-kappaB. It is suggested that the soluble B6H12 exerts a negative effect on the maturation and function of in vitro cultured DCs due to inhibition of NF-kappaB binding activity.
Antibodies, Monoclonal ; immunology ; pharmacology ; Antigens, CD ; biosynthesis ; Antigens, CD1 ; biosynthesis ; B7-1 Antigen ; biosynthesis ; B7-2 Antigen ; biosynthesis ; CD47 Antigen ; immunology ; Cell Size ; drug effects ; Cells, Cultured ; Dendritic Cells ; cytology ; drug effects ; metabolism ; Electrophoretic Mobility Shift Assay ; Enzyme-Linked Immunosorbent Assay ; Flow Cytometry ; HLA-DR Antigens ; biosynthesis ; Humans ; Immunoglobulins ; biosynthesis ; Interleukin-12 ; metabolism ; Membrane Glycoproteins ; biosynthesis ; NF-kappa B ; metabolism ; Oligonucleotides ; metabolism ; Protein Binding

OBJECTIVETo explore the influences of anti-CD47 monoclonal antibody (mAb) B6H12 on the differentiation and function of cultured dendritic cells (DCs).

METHODSHuman peripheral monocyte derived DCs were propagated with granulocyte-macrophage colony-stimulating factor (GM-CSF) and lipopolysaccharide (LPS) plus interleukin-4 (IL-4) in the presence or absence of soluble B6H12. Flow cytometry was used to analyze the immunophenotypes of cells, semi-quantitative RT-PCR and ELISA methods to analyse the mRNA and protein expression levels of interleukin-12 (IL-12). The antigen-presenting function of DCs was determined in one-way mixed leukocyte reaction by Brdu-ELISA technique.

RESULTSThere was a high expression rate (94% approximately 98%) of CD47 molecules in DCs. The cell immunophenotypes in B6H12 mAb treated and untreated DC groups were as follows: CD80(+) (68.14 +/- 7.41)% vs (89.17 +/- 8.59)%; CD86(+) (67.33 +/- 4.71)% vs (87.27 +/- 3.56)%; CD83 (40.08 +/- 14.80)% vs (72.77 +/- 8.68)%; CD1a(+) (66.45 +/- 4.06)% vs (95.93 +/- 3.03)%; and HLA-DR (40.67 +/- 13.48) vs (98.97 +/- 1.01)%, respectively. The expression levels of mRNA and protein of IL-12 were strongly inhibited in B6H12 mAb treated DC (P < 0.01). The quantity of Brdu was also lower in B6H12 mAb treated DC than that in untreated DCs (P < 0.01).

CONCLUSIONThe anti-CD47 McAb exerts a negative effect on the maturation and functions of cultured DCs.

Adult ; Antibodies, Monoclonal ; pharmacology ; Antigens, CD ; analysis ; Antigens, CD1 ; analysis ; B7-2 Antigen ; analysis ; CD47 Antigen ; analysis ; immunology ; Cell Differentiation ; drug effects ; Cell Proliferation ; drug effects ; Cells, Cultured ; Dendritic Cells ; cytology ; drug effects ; metabolism ; Enzyme-Linked Immunosorbent Assay ; Flow Cytometry ; Granulocyte-Macrophage Colony-Stimulating Factor ; pharmacology ; Humans ; Immunoglobulins ; analysis ; Interleukin-12 ; genetics ; metabolism ; Interleukin-4 ; pharmacology ; Lipopolysaccharides ; pharmacology ; Membrane Glycoproteins ; analysis ; Monocytes ; cytology ; drug effects ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction

CD47, also known as integrin-associated protein (IAP), is an immunoglobulin-like protein. It can inhibit the phagocytosis of macrophages through binding with signal-regulatory protein alpha chain of inhibitory receptor on macrophage (SIRPα). The expression of CD47 on normal hematopoietic stem cells (HSCs) is useful for maintaining the stability of HSCs in body, but the high expression of CD47 existed on leukemia stem cell (LSCs) of AML patients which can reduce the macrophage-induced phagocytosis to LSCs and decrease the clearance of innate immune system of organism to LSCs. In this article, the expression and function of CD47 on HSCs and LSCs as well as the role of CD47 in the prognosis and target therapy of AML are reviewed.
CD47 Antigen ; metabolism ; Humans ; Leukemia ; metabolism ; Macrophages ; metabolism ; Neoplastic Stem Cells ; metabolism ; Phagocytosis

OBJECTIVE: To investigate the expression of CD47 molecules in patients with newly diagnosis of adult acute myeloid leukemia (AML) and its correlation with clinical prognosis. METHODS: 20 patients with acute myeloid leukemia diagnosed in Shanghai Fengxian District Central hospital from April 2020 to October 2021 and 5 cases with non malignant hematological diseases in the control group were collected, and the expression of CD47 in single nuclear cells of bone marrow and peripheral blood was detected by real-time fluorescence quantitative polymerase chain reaction (qPCR). Combined with the blood image, bone marrow smears, flow cytometry, chromosome and gene detection, ECOG score, etc. during the patient's initial diagnosis, the relationship between the patient's prognosis and CD47 was evaluated. RESULTS: The expression of CD47 in bone marrow (P=0.0115) and peripheral blood mononuclear cells (P=0.0069) in new diagnosis AML patients was significantly higher than that of controls. In bone marrow mononuclear cells, the total survival time of patients with high CD47 expression was less than that of CD47 low expression patients (P=0.036). There was statistical significance in difference stratification group (P=0.012), but there was no statistical significance between CD47 expression and survival time in peripheral blood mononuclear cells (P=0.116). There were no statistical significance between bone marrow mononuclear cell CD47 expression and gene mutation fusion genes related to leukemia , CD34⁺, CD38⁺, CD123⁺ (P>0.05). The proportion of bone marrow protocells in AML patients was >50%, the ECOG score was >2 points, MLLELL fusion gene and chromosome prognosis stratification were all risk factors affecting the survival of patients (P=0023, 0.036, 0.012, 0.001, respectively). The high expression of bone marrow CD47 in AML patients indicated a high risk of recurrence (P=0.017). CONCLUSION The high expression of bone marrow mononuclear cell CD47 in AML patients indicates poorer survival and higher risk of recurrence.
Adult ; CD47 Antigen ; China ; Humans ; Leukemia, Myeloid, Acute/genetics* ; Leukocytes, Mononuclear/pathology* ; Prognosis

OBJECTIVE: To investigate the effect of hypoxia on hypoxia-inducible factor 1α (HIF-1α) and CD47 expression in human acute myeloid leukemia (AML) cell lines. METHODS: The CD47 expression in AML U937, HL-60, and K562 cells lines were detected by flow cytometry. U937, HL-60, and K562 cells were all divided into hypoxia-treated group and conventional oxygen group. The hypoxia-treated group was cultured with 1% O₂, while the conventional oxygen group was cultured with 20% O₂, then the cells were collected after 24 hours. Real time PCR was used to examine the mRNA changes of CD47 gene. Western blot assay was applied to detect the protein expression of HIF-1α and CD47. RESULTS: The expression of CD47 in U937, HL-60, and K562 cells was 98% (98%±0.03%), 99% (99%±0.05%), and 75% (75%±0.11%), respectively. The real time PCR showed that the mRNA expression of CD47 in U937 and HL-60 cells were up-regulated in the hypoxia-treated group (P<0.05), while in K562 cells was not (P>0.05). Western blot result showed that the protein levels of HIF-1α and CD47 of U937, HL-60, and K562 cells in the hypoxia-treated group were increased compared with the conventional oxygen group (P<0.05). CONCLUSION The hypoxia can up-regulate the expression of CD47 in acute myeloid leukemia cells, which may be related to HIF-1α.
CD47 Antigen ; Humans ; Hypoxia ; Hypoxia-Inducible Factor 1, alpha Subunit ; K562 Cells ; Leukemia, Myeloid, Acute ; Oxygen ; RNA, Messenger/metabolism*

BACKGROUND: Lung cancer has a high incidence and mortality rate, but the treatment of lung cancer still lacks low toxicity and efficient anti-tumor drugs. Polysaccharide from radix tetrastigme has development value in anti-tumor treatment methods. This study was to observe the effect of polysaccharide from radix tetrastigme on immune response of Lewis lung cancer mice and explore its molecular mechanism. METHODS: Lewis lung cancer mouse models were established and randomly grouped. The spleen polypeptide group was intragastric with 50 mg/kg spleen polypeptide, and the radix tetrastigme polysaccharide low, medium and high dose groups were intragastric with 62.5, 125 and 250 mg/kg radix tetrastigme polysaccharide, respectively, and the model group and the control group were intragastric with equivolume normal saline. Tumor formation and metastasis were compared. Haematoxylin-eosin (HE) staining was used to observe the pathological changes of tumor cells. Macrophage phagocytosis, apoptosis, M1/M2 polarization, T cell subsets and cytokine levels in peripheral blood were detected by flow cytometry. The proliferation activity of macrophages was detected by methyl thiazolyldiphenyl tetrazolium (MTT) assay. Dendritic cell (DC) antigen presenting function was detected by chlorophenol red-β-D-galactopyranoside (CPRG) method. Tumor tissue differentiation antigen cluster 47 (CD47) mRNA and protein expression and macrophage signal regulatory protein α (SIRRP α) expression were detected by real time quantitative polymerase chain reaction (RT-qPCR) and Western blot (WB). RESULTS: The tumor inhibition rates and anti-metastasis rates in the 3-dose radix tetrastigme polysaccharide group and the spleen polypeptide group were higher than those in the model group, and the pathological injury of tumor tissue were severer, and the positive rate of phagocytosis of ink by macrophages and the efficiency of phagocytosis of tumor cells were increased; the apoptosis rate of macrophages was decreased; the proliferation activity of macrophages, polarization ratio of macrophages to M1 type, DC antigen presenting ability, CD4+, CD4+/CD8+ levels were increased; the level of serum tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), and the expression of tumor tissue CD47, macrophage SH2-containing protein tyrosine phosphatase 1 (SHP-1), SH2-containing protein tyrosine phosphatase 2 (SHP-2), and phosphorylation signal regulatory protein α (p-SIRPα) were decreased, and the differences were statistically significant (P<0.05). There were no significant differences in the above indexes between low-dose radix tetrastigme polysaccharide group and spleen polypeptide group (P>0.05), and the effects of radix tetrastigme polysaccharide were dose-dependent. CONCLUSIONS Radix tetrastigme polysaccharide can inhibit tumor growth, metastasis and immune response in Lewis lung cancer mice, and its mechanism may be related to inhibiting SIRP/CD47 signaling pathway.
Mice ; Animals ; CD47 Antigen/genetics* ; Lung Neoplasms/drug therapy* ; Cytokines/genetics* ; Polysaccharides/pharmacology* ; Immunity ; Protein Tyrosine Phosphatases

Objective To investigate the expressions of CD44,CD47,and c-met in ovarian clear cell carcinoma (OCCC) tissue and their correlations with clinical variables and prognosis. Methods Immunohistochemical method was used to investigate the expressions of CD44,CD47,and c-met in tissues from 86 OCCC patients and the relationships of their expressions with the clinicopathological factors of OCCC were analyzed. Results The expressions of CD44,CD47,and c-met were significantly high in OCCC tissues (90.7%,91.9%,and 94.2%,respectively). The strong positive expressions of CD44 and CD47 were significantly correlated with advanced International Federation of Gynecology and Obstetrics stages,chemotherapeutic resistance,and poor prognosis (all P<0.05),the strong positive expression of c-met was significantly correlated with chemotherapeutic resistance and poor prognosis (all P<0.05),whereas there was no correlation between the strong positive expressions of CD44,CD47,and c-met and the lymphatic node metastasis. COX survival analysis revealed that advanced International Federation of Gynecology and Obstetrics stages and high expressions of CD44,CD47 and c-met were independent risk factors for poor prognosis (P<0.05). There was a positive correlation between CD44 (or CD47) and c-met and between CD44 and CD47 (the Spearman correlation coefficient rwas 0.783,0.776,and 0.835,respectively,all P<0.01). Conclusions The expressions of CD44,CD47,and c-met increase in OCCC tissues and are correlated with each other. High expressions of CD44,CD47,and c-met are independent factors for poor prognosis.
Adenocarcinoma, Clear Cell ; metabolism ; CD47 Antigen ; metabolism ; Female ; Humans ; Hyaluronan Receptors ; metabolism ; Lymphatic Metastasis ; Ovarian Neoplasms ; metabolism ; Prognosis ; Proto-Oncogene Proteins c-met ; metabolism ; Survival Analysis

The third-generation epidermal growth factor receptor (EGFR) inhibitor osimertinib (OSI) has been approved as the first-line treatment for EGFR-mutant non-small cell lung cancer (NSCLC). This study aims to explore a rational combination strategy for enhancing the OSI efficacy. In this study, OSI induced higher CD47 expression, an important anti-phagocytic immune checkpoint, via the NF-κB pathway in EGFR-mutant NSCLC HCC827 and NCI-H1975 cells. The combination treatment of OSI and the anti-CD47 antibody exhibited dramatically increasing phagocytosis in HCC827 and NCI-H1975 cells, which highly relied on the antibody-dependent cellular phagocytosis effect. Consistently, the enhanced phagocytosis index from combination treatment was reversed in CD47 knockout HCC827 cells. Meanwhile, combining the anti-CD47 antibody significantly augmented the anticancer effect of OSI in HCC827 xenograft mice model. Notably, OSI induced the surface exposure of "eat me" signal calreticulin and reduced the expression of immune-inhibitory receptor PD-L1 in cancer cells, which might contribute to the increased phagocytosis on cancer cells pretreated with OSI. In summary, these findings suggest the multidimensional regulation by OSI and encourage the further exploration of combining anti-CD47 antibody with OSI as a new strategy to enhance the anticancer efficacy in EGFR-mutant NSCLC with CD47 activation induced by OSI.
Humans ; Mice ; Animals ; Carcinoma, Non-Small-Cell Lung/metabolism* ; Lung Neoplasms/metabolism* ; Acrylamides/pharmacology* ; ErbB Receptors/metabolism* ; Cell Line, Tumor ; CD47 Antigen/therapeutic use*