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Background: Cancer immunotherapy, particularly immune checkpoint inhibitors (ICBs) such as anti-PD-1 antibodies, has revolutionised cancer treatment, although response rates vary among patients. Previous studies have demonstrated that caerin 1.1 and 1.9, host-defence peptides from the Australian tree frog, enhance the effectiveness of anti-PD-1 and therapeutic vaccines in a murine TC-1 model by activating tumour-associated macrophages intratumorally. Methods: We employed a murine B16 melanoma model to investigate the therapeutic potential of caerin 1.1 and 1.9 in combination with anti-CD47 and a therapeutic vaccine (triple therapy, TT). Tumour growth of caerin-injected primary tumours and distant metastatic tumours was assessed, and survival analysis conducted. Single-cell RNA sequencing (scRNAseq) of CD45+ cells isolated from distant tumours was performed to elucidate changes in the tumour microenvironment induced by TT. Results: The TT treatment significantly reduced tumour volumes on the treated side compared to untreated and control groups, with notable effects observed by Day 21. Survival analysis indicated extended survival in mice receiving TT, both on the treated and distant sides. scRNAseq revealed a notable expansion of conventional type 1 dendritic cells (cDC1s) and CD4+CD8+ T cells in the TT group. Tumour-associated macrophages in the TT group shifted toward a more immune-responsive M1 phenotype, with enhanced communication observed between cDC1s and CD8+ and CD4+CD25+ T cells. Additionally, TT downregulated M2-like macrophage marker genes, particularly in MHCIIhi and tissue-resident macrophages, suppressing Cd68 and Arg1 expression across all macrophage types. Differential gene expression analysis highlighted pathway alterations, including upregulation of oxidative phosphorylation and MYC target V1 in Arg1hi macrophages, and activation of pro-inflammatory pathways in MHCIIhi and tissue-resident macrophages. Conclusion: Our findings suggest that caerin 1.1 and 1.9, combined with immunotherapy, effectively modulate the tumour microenvironment in primary and secondary tumours, leading to reduced tumour growth and enhanced systemic immunity. Further investigation into these mechanisms could pave the way for improved combination therapies in advanced melanoma treatment. [ABSTRACT FROM AUTHOR]

CD47 is a cell-surface ligand that is overexpressed in various malignancies and that binds to SIRPα on macrophages to promote tumor cell evasion of phagocytosis. Blocking the CD47-SIRPα axis can increase the phagocytosis of macrophages to exert antitumor effects. CD47-based immunotherapy is a current research focus. The combination of anti-CD47 antibodies with other drugs has shown encouraging response rates in patients with hematological tumors, but side effects also occur. Bispecific antibodies and SIRPα/Fc fusion proteins appear to balance the efficacy and safety of treatment. We review the latest clinical research advances and discuss the opportunities and challenges associated with CD47-based immunotherapy for hematological malignancies. [ABSTRACT FROM AUTHOR]

Infiltrative glioma growth makes surgical excision incomplete, and the residual tumor cells proliferate rapidly. Residual glioma cells evade phagocytosis by macrophages through upregulating anti-phagocytosis molecule CD47, which binds to the signal regulatory protein alpha (SIRPα) of macrophages. Specifically, blocking the CD47-SIRPα pathway is a potential strategy for post-resection glioma treatment. In addition, the anti-CD47 antibody (α-CD47) in combination with temozolomide (TMZ) caused an enhanced pro-phagocytic effect due to the TMZ not only destroying DNA but also inducing endoplasmic reticulum stress response of glioma cells. However, the obstruction of the blood-brain barrier makes systemic combination therapy not ideal for post-resection glioma treatment. Herein, we designed a temperature-sensitive hydrogel system based on a moldable thermosensitive hydroxypropyl chitin (HPCH) copolymer to encapsulate both α-CD47 and TMZ as α-CD47&TMZ@Gel for in situ postoperative cavity administration. Through the in vitro and in vivo evaluations, α-CD47&TMZ@Gel significantly inhibited glioma recurrence post-resection through enhancement of pro-phagocytosis of macrophages, recruitment, and activation of CD8+ T cells and NK cells. [Display omitted] [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

CD47 expressed on cancer cells enables macrophage immune evasion. Blocking CD47 using anti‐CD47 monoclonal antibodies (mAbs) is a promising strategy. The anti‐CD47 mAb TJC4 has anti‐tumor activity but lacks hematological toxicity. Venetoclax, a B‐cell lymphoma 2 (BCL‐2) inhibitor for B‐cell malignancy, induces phosphatidylserine (PS) extracellular exposure, representing an "eat‐me" signal for macrophages. The present study aimed to explore whether TJC4‐Venetoclax combined therapy exerts synergistic anti‐cancer properties in B‐cell lymphoma. In vitro, flow cytometry and microscopy assessed whether TJC4 monotherapy or combination treatment could promote macrophage‐mediated phagocytosis of tumor cells. Induced PS exposure on the cell membrane was measured using flow cytometry with Annexin V‐FITC staining. In vivo, Venetoclax and TJC4's synergistic anti‐tumor effects were evaluated. B cell lymphoma cell lines express high levels of CD47 and patients with diffuse large B cell lymphoma expressing CD47 have a worse clinical prognosis. TJC4 eliminates tumor cells via macrophage‐mediated phagocytosis. In vitro and in vivo, the TJC4‐Venetoclax combination increased phagocytosis significantly compared with either agent alone, showing synergistic phagocytosis, and displayed synergistic anti‐cancer properties in B‐cell lymphoma. Our results support the TJC4‐Venetoclax combination as a promising therapy, and suppressing BCL‐2 and CD47 simultaneously could represent a novel therapeutic paradigm for B‐cell lymphoma. [ABSTRACT FROM AUTHOR]

The European LeukemiaNet (ELN) criteria define the adverse genetic factors of acute myeloid leukemia (AML). AML with adverse genetic factors uniformly shows resistance to standard chemotherapy and is associated with poor prognosis. Here, we focus on the biological background and real-world etiology of these adverse genetic factors and then describe a strategy to overcome the clinical disadvantages in terms of targeting pivotal molecular mechanisms. Different adverse genetic factors often rely on common pathways. KMT2A rearrangement, DEK-NUP214 fusion, and NPM1 mutation are associated with the upregulation of HOX genes. The dominant tyrosine kinase activity of the mutant FLT3 or BCR-ABL1 fusion proteins is transduced by the AKT-mTOR, MAPK-ERK, and STAT5 pathways. Concurrent mutations of ASXL1 and RUNX1 are associated with activated AKT. Both TP53 mutation and mis-expressed MECOM are related to impaired apoptosis. Clinical data suggest that adverse genetic factors can be found in at least one in eight AML patients and appear to accumulate in relapsed/refractory cases. TP53 mutation is associated with particularly poor prognosis. Molecular-targeted therapies focusing on specific genomic abnormalities, such as FLT3, KMT2A, and TP53, have been developed and have demonstrated promising results. [ABSTRACT FROM AUTHOR]

Abstract The highly immunosuppressive microenvironment after surgery has a crucial impact on the recurrence and metastasis in breast cancer patients. Programmable delivery of immunotherapy-involving combinations through a single drug delivery system is highly promising, yet greatly challenging, to reverse postoperative immunosuppression. Here, an injectable hierarchical gel matrix, composed of dual lipid gel (DLG) layers with different soybean phosphatidylcholine/glycerol dioleate mass ratios, was developed to achieve the time-programmed sequential delivery of combined cancer immunotherapy. The outer layer of the DLG matrix was thermally responsive and loaded with sorafenib-adsorbed graphene oxide (GO) nanoparticles. GO under manually controlled near-infrared irradiation generated mild heat and provoked the release of sorafenib first to reeducate tumor-associated macrophages (TAMs) and promote an immunogenic tumor microenvironment. The inner layer, loaded with anti-CD47 antibody (aCD47), could maintain the gel state for a much longer time, enabling the sustained release of aCD47 afterward to block the CD47-signal regulatory protein α (SIRPα) pathway for a long-term antitumor effect. In vivo studies on 4T1 tumor-bearing mouse model demonstrated that the DLG-based strategy efficiently prevented tumor recurrence and metastasis by locally reversing the immunosuppression and synergistically blocking the CD47-dependent immune escape, thereby boosting the systemic immune responses.

Limited therapeutic options are available for patients with breast cancer brain metastases (BCBM), and thus there is an urgent need for novel treatment approaches. We previously engineered an effective oncolytic herpes simplex virus 1 (oHSV) expressing a full-length anti-CD47 monoclonal antibody (mAb) with a human IgG1 scaffold (OV-αCD47-G1) that was used to treat both ovarian cancer and glioblastoma. Here, we demonstrate that the combination of OV-αCD47-G1 and temozolomide (TMZ) improve outcomes in preclinical models of BCBM. The combination of TMZ with OV-αCD47-G1 synergistically increased macrophage phagocytosis against breast tumor cells and led to greater activation of NK cell cytotoxicity. In addition, the combination of OV-αCD47-G1 with TMZ significantly prolonged the survival of tumor-bearing mice when compared with TMZ or OV-αCD47-G1 alone. Combination treatment with the mouse counterpart of OV-αCD47-G1, termed OV-A4-IgG2b, also enhanced mouse macrophage phagocytosis, NK cell cytotoxicity, and survival in an immunocompetent model of mice bearing BCBM compared with TMZ or OV-A4-IgG2b alone. Collectively, these results suggest that OV-αCD47-G1 combined with TMZ should be explored in patients with BCBM., Competing Interests: M.A.C. and J.Y. have relevant or non-relevant oncolytic virus patents pending., (© 2024 The Authors. Published by Elsevier Inc. on behalf of The American Society of Gene and Cell Therapy.)

• Anti-CD47 antibody was administrated into the cisterna magna after ICH in rats. • Proper dosage anti-CD47 antibody can effectively reach the hematoma site. • More MG/Møs gather around hematoma to phagocytize RBCs after using proper antibody. • Death cells in perihematomal tissue were reduced due to proper antibody usage. • The results of this study has provided a basis theory for further research. The secondary injury caused by RBC autolysis after intracerebral hemorrhage (ICH) can be reduced by increasing the efficiency of microglia (MG)/macrophages (Mø) phagocytizing red blood cells (RBCs). CD47 is an important regulator of MG/Mø phagocytosis. This study aims to clarify whether anti-CD47 antibody administrated into the cisterna magna after ICH can transfer to the hematoma site, promote MG/Mø gathering to phagocytize RBCs and ultimately reduce cell death. Forty male Wistar rats were divided into sham, ICH, low-dosage (group A, 0.3 μg), medium-dosage (group B, 0.9 μg) and high-dosage (group C, 1.8 μg) anti-CD47 antibody groups. For the rats in group A, B and C, anti-CD47 antibody solution was administrated into the cisterna magna at 10 min after ICH. Brain tissue was harvested 3 days after the operation. Western blotting was performed to detect the expression of Caspase-3 and Bcl-2. Immunofluorescence was performed to detect the CD68 expression. TUNEL was performed to detect the cell death. The hematoma of the ICH rats was located in the basal ganglia, with a good homogeneity of hematoma volume. Low-dosage anti-CD47 antibody in group A had no effects on the perihematomal CD68 (P = 0.338), Caspase-3 (P = 0.769), Bcl-2 (P = 0.176) expression and cell death (P = 0.698), compared with the ICH group. CD68 and Bcl-2 expression increased and Caspase-3 expression decreased significantly in group B (P < 0.001 for all) and group C (P < 0.001 for all). The increase of CD68 expression in group C was greater than that in group B (P < 0.01) by a large margin, while there was no difference for Bcl-2 (P = 0.908) and Caspase-3 (P = 0.913) expression between the 2 groups. Compared with the ICH group, medium-dosage of anti-CD47 antibody in group B significantly reduced the number of TUNEL-positive cells (P < 0.005), but not for group C (P = 0.311). The results suggested that anti-CD47 antibody administration into the cisterna magna in proper dosage (0.9 μg) can effectively reach the hematoma, induce more MG/Møs to gather around the hematoma, and reduce cell death in perihematomal brain tissue. The results of this study has provided a basic theory for improving the efficiency of MG/Mø phagocytizing RBCs and hematoma clearance after ICH by administrating anti-CD47 antibody via the cisterna magna. [ABSTRACT FROM AUTHOR]

Highlights: A novel injectable double-layer-gel matrix is developed. The hierarchically structured dual lipid gel matrix enables time-programmed drug delivery. Applying a modest dose of sorafenib in advance can reeducate tumor-associated macrophages and potentiate anti-CD47 treatment.The highly immunosuppressive microenvironment after surgery has a crucial impact on the recurrence and metastasis in breast cancer patients. Programmable delivery of immunotherapy-involving combinations through a single drug delivery system is highly promising, yet greatly challenging, to reverse postoperative immunosuppression. Here, an injectable hierarchical gel matrix, composed of dual lipid gel (DLG) layers with different soybean phosphatidylcholine/glycerol dioleate mass ratios, was developed to achieve the time-programmed sequential delivery of combined cancer immunotherapy. The outer layer of the DLG matrix was thermally responsive and loaded with sorafenib-adsorbed graphene oxide (GO) nanoparticles. GO under manually controlled near-infrared irradiation generated mild heat and provoked the release of sorafenib first to reeducate tumor-associated macrophages (TAMs) and promote an immunogenic tumor microenvironment. The inner layer, loaded with anti-CD47 antibody (aCD47), could maintain the gel state for a much longer time, enabling the sustained release of aCD47 afterward to block the CD47-signal regulatory protein α (SIRPα) pathway for a long-term antitumor effect. In vivo studies on 4T1 tumor-bearing mouse model demonstrated that the DLG-based strategy efficiently prevented tumor recurrence and metastasis by locally reversing the immunosuppression and synergistically blocking the CD47-dependent immune escape, thereby boosting the systemic immune responses. [ABSTRACT FROM AUTHOR]

CD47 is a cell-surface ligand that is overexpressed in various malignancies and that binds to SIRPα on macrophages to promote tumor cell evasion of phagocytosis. Blocking the CD47-SIRPα axis can increase the phagocytosis of macrophages to exert antitumor effects. CD47-based immunotherapy is a current research focus. The combination of anti-CD47 antibodies with other drugs has shown encouraging response rates in patients with hematological tumors, but side effects also occur. Bispecific antibodies and SIRPα/Fc fusion proteins appear to balance the efficacy and safety of treatment. We review the latest clinical research advances and discuss the opportunities and challenges associated with CD47-based immunotherapy for hematological malignancies., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Xu, Jiang, Xu and Ye.)

Multiple myeloma (MM) remains an incurable hematologic malignancy due to its frequent drug resistance and relapse. Cluster of Differentiation 47 (CD47) is reported to be highly expressed on MM cells, suggesting that the blockade of CD47 signaling pathway could be a potential therapeutic candidate for MM. In this study, we developed a bortezomib-resistant myeloma patient-derived xenograft (PDX) from an extramedullary pleural effusion myeloma patient sample. Notably, anti-CD47 antibody treatments significantly inhibited tumor growth not only in MM cell line-derived models, including MM.1S and NCI-H929, but also in the bortezomib-resistant MM PDX model. Flow cytometric data showed that anti-CD47 therapy promoted the polarization of tumor-associated macrophages from an M2- to an M1-like phenotype. In addition, anti-CD47 therapy decreased the expression of pro-angiogenic factors, increased the expression of anti-angiogenic factors, and improved tumor vascular function, suggesting that anti-CD47 therapy induces tumor vascular normalization. Taken together, these data show that anti-CD47 antibody therapy reconditions the tumor immune microenvironment and inhibits the tumor growth of bortezomib-resistant myeloma PDX. Our findings suggest that CD47 is a potential new target to treat bortezomib-resistant MM. [Display omitted] • Anti-CD47 therapy inhibits the growth of bortezomib-resistant MM. • Anti-CD47 therapy polarizes tumor-associated macrophages from M2 to M1 phenotype in MM. • Anti-CD47 therapy normalizes tumor vascular function in MM. [ABSTRACT FROM AUTHOR]

Cancer is still a major disease that is currently difficult for humans to overcome. When the expression of the cluster of differentiation 47 (CD47) is upregulated, tumor cells interact with the macrophage inhibitory receptor signal regulatory protein α (SIRPα) to transmit the "Don't eat me" signal, thereby avoiding phagocytosis by the macrophages. Therefore, when the CD47-SIRPα axis is inhibited, the macrophages' phagocytic function can be restored and can also exert antitumor effects. This Review mainly introduces recent advances in tumor therapy targeted on the CD47-SIRPα axis, including the antibody and fusion protein, small molecule, gene therapy, cell therapy, and drug delivery system, to inhibit the function of CD47 expressed on tumor cells and promote tumor phagocytosis by macrophages. In addition, this Review also summarizes the current approaches to avoid anemia, a common side effect of CD47-SIRPα inhibitions, and provides ideas for clinical transformation.

CD47/SIRPα interaction serves as an immune checkpoint for macrophage-mediated phagocytosis. Mouse anti-CD47 blocking antibodies had demonstrated potent efficacy in the treatment of both leukemic and solid tumors in preclinical experimentations, and therefore had moved forward rapidly into clinical trials. However, a fully human blocking antibody, which meets clinical purpose better, has not been reported for CD47 up to date. In this study, we reported the isolation of a fully human anti-CD47 blocking antibody, ZF1, from a phage display library. ZF1 displayed high specificity and affinity for CD47 protein, which were comparable to those for humanized anti-CD47 blocking antibody B6H12. Importantly, ZF1 treatment could induce robust, or even stronger than B6H12, phagocytosis of leukemic cancer cells by macrophage in vitro, and protect BALB/c nude mice from cancer killing by engrafted leukemic cells (CCRF and U937) to a similar extent as B6H12 did. Thus, these data provide primary early pre-clinical support for the development of ZF1 as a fully human blocking antibody to treat human leukemia by targeting CD47 molecule.