Codelivery of anti-CD47 antibody and chlorin e6 using a dual pH-sensitive nanodrug for photodynamic immunotherapy of osteosarcoma.

Osteosarcoma is a malignant tumor originating from bone tissue that progresses rapidly and has a poor patient prognosis. Immunotherapy has shown great potential in the treatment of osteosarcoma. However, the immunosuppressive microenvironment severely limits the efficacy of osteosarcoma treatment. The dual pH-sensitive nanocarrier has emerged as an effective antitumor drug delivery system that can selectively release drugs into the acidic tumor microenvironment. Here, we prepared a dual pH-sensitive nanocarrier, loaded with the photosensitizer Chlorin e6 (Ce6) and CD47 monoclonal antibodies (aCD47), to deliver synergistic photodynamic and immunotherapy of osteosarcoma. On laser irradiation, Ce6 can generate reactive oxygen species (ROS) to kill cancer cells directly and induces immunogenic tumor cell death (ICD), which further facilitates the dendritic cell maturation induced by blockade of CD47 by aCD47. Moreover, both calreticulin released during ICD and CD47 blockade can accelerate phagocytosis of tumor cells by macrophages, promote antigen presentation, and eventually induce T lymphocyte-mediated antitumor immunity. Overall, the dual pH-sensitive nanodrug loaded with Ce6 and aCD47 showed excellent immune-activating and anti-tumor effects in osteosarcoma, which may lay the theoretical foundation for a novel combination model of osteosarcoma treatment.

Targeting CD73 with flavonoids inhibits cancer stem cells and increases lymphocyte infiltration in a triple-negative breast cancer mouse model.

Introduction: Chemotherapy remains the mainstay treatment for triple-negative breast cancer (TNBC) due to the lack of specific targets. Given a modest response of immune checkpoint inhibitors in TNBC patients, improving immunotherapy is an urgent and crucial task in this field. CD73 has emerged as a novel immunotherapeutic target, given its elevated expression on tumor, stromal, and specific immune cells, and its established role in inhibiting anti-cancer immunity. CD73-generated adenosine suppresses immunity by attenuating tumor-infiltrating T- and NK-cell activation, while amplifying regulatory T cell activation. Chemotherapy often leads to increased CD73 expression and activity, further suppressing anti-tumor immunity. While debulking the tumor mass, chemotherapy also enriches heterogenous cancer stem cells (CSC), potentially leading to tumor relapse. Therefore, drugs targeting both CD73, and CSCs hold promise for enhancing chemotherapy efficacy, overcoming treatment resistance, and improving clinical outcomes. However, safe and effective inhibitors of CD73 have not been developed as of now. Methods: We used in silico docking to screen compounds that may be repurposed for inhibiting CD73. The efficacy of these compounds was investigated through flow cytometry, RT-qPCR, CD73 activity, cell viability, tumorsphere formation, and other in vitro functional assays. For assessment of clinical translatability, TNBC patient-derived xenograft organotypic cultures were utilized. We also employed the ovalbumin-expressing AT3 TNBC mouse model to evaluate tumor-specific lymphocyte responses. Results: We identified quercetin and luteolin, currently used as over-the-counter supplements, to have high in silico complementarity with CD73. When quercetin and luteolin were combined with the chemotherapeutic paclitaxel in a triple-drug regimen, we found an effective downregulation in paclitaxel-enhanced CD73 and CSC-promoting pathways YAP and Wnt. We found that CD73 expression was required for the maintenance of CD44highCD24low CSCs, and co-targeting CD73, YAP, and Wnt effectively suppressed the growth of human TNBC cell lines and patient-derived xenograft organotypic cultures. Furthermore, triple-drug combination inhibited paclitaxel-enriched CSCs and simultaneously improved lymphocyte infiltration in syngeneic TNBC mouse tumors. Discussion: Conclusively, our findings elucidate the significance of CSCs in impairing anti-tumor immunity. The high efficacy of our triple-drug regimen in clinically relevant platforms not only underscores the importance for further mechanistic investigations but also paves the way for potential development of new, safe, and cost-effective therapeutic strategies for TNBC.

Difference between Keratinized- and Non-Keratinized-Originating Epithelium in the Process of Immune Escape of Oral Squamous Cell Carcinoma.

Immune checkpoint inhibitors (ICIs), including anti-programmed cell death 1 ligand 1 (PD-L1) antibodies, are significantly changing treatment strategies for human malignant diseases, including oral cancer. Cancer cells usually escape from the immune system and acquire proliferative capacity and invasive/metastatic potential. We have focused on the two immune checkpoints, PD-1/PD-L1 and CD47/SIRPα, in the tumor microenvironment of oral squamous cell carcinoma (OSCC), performed a retrospective analysis of the expression of seven immune-related factors (PD-L1, PD-1, CD4, CD8, CD47, CD56 and CD11c), and examined their correlation with clinicopathological status. As a result, there were no significant findings relating to seven immune-related factors and several clinicopathological statuses. However, the immune checkpoint-related factors (PD-1, PD-L1, CD47) were highly expressed in non-keratinized epithelium-originated tumors when compared to those in keratinized epithelium-originated tumors. It is of interest that immunoediting via immune checkpoint-related factors was facilitated in non-keratinized sites. Several researchers reported that the keratinization of oral mucosal epithelia affected the immune response, but our present finding is the first study to show a difference in tumor immunity in the originating epithelium of OSCC, keratinized or non-keratinized. Tumor immunity, an immune escape status of OSCC, might be different in the originating epithelium, keratinized or non-keratinized.

Development of ISB 1442, a CD38 and CD47 bispecific biparatopic antibody innate cell modulator for the treatment of multiple myeloma.

Antibody engineering can tailor the design and activities of therapeutic antibodies for better efficiency or other advantageous clinical properties. Here we report the development of ISB 1442, a fully human bispecific antibody designed to re-establish synthetic immunity in CD38+ hematological malignancies. ISB 1442 consists of two anti-CD38 arms targeting two distinct epitopes that preferentially drive binding to tumor cells and enable avidity-induced blocking of proximal CD47 receptors on the same cell while preventing on-target off-tumor binding on healthy cells. The Fc portion of ISB 1442 is engineered to enhance complement dependent cytotoxicity, antibody dependent cell cytotoxicity and antibody dependent cell phagocytosis. ISB 1442 thus represents a CD47-BsAb combining biparatopic targeting of a tumor associated antigen with engineered enhancement of antibody effector function to overcome potential resistance mechanisms that hamper treatment of myeloma with monospecific anti-CD38 antibodies. ISB 1442 is currently in a Phase I clinical trial in relapsed refractory multiple myeloma.

Expression of a mutant CD47 protects against phagocytosis without inducing cell death or inhibiting angiogenesis.

CD47 is a ligand of SIRPα, an inhibitory receptor expressed by macrophages, dendritic cells, and natural killer (NK) cells, and, therefore, transgenic overexpression of CD47 is considered an effective approach to inhibiting transplant rejection. However, the detrimental effect of CD47 signaling is overlooked when exploring this approach. Here, we construct a mutant CD47 by replacing the transmembrane and intracellular domains with a membrane anchor (CD47-IgV). In both human and mouse cells, CD47-IgV is efficiently expressed on the cell surface and protects against phagocytosis in vitro and in vivo but does not induce cell death or inhibit angiogenesis. Furthermore, hematopoietic stem cells expressing transgenic CD47-IgV show no detectable alterations in engraftment or differentiation. This study provides a potentially effective means of achieving transgenic CD47 expression that may help to produce gene-edited pigs for xenotransplantation and hypoimmunogenic pluripotent stem cells for regenerative medicine.

Opportunities and challenges for anti-CD47 antibodies in hematological malignancies.

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.

NSUN5/TET2-directed chromatin-associated RNA modification of 5-methylcytosine to 5-hydroxymethylcytosine governs glioma immune evasion.

Malignant glioma exhibits immune evasion characterized by highly expressing the immune checkpoint CD47. RNA 5-methylcytosine(m5C) modification plays a pivotal role in tumor pathogenesis. However, the mechanism underlying m5C-modified RNA metabolism remains unclear, as does the contribution of m5C-modified RNA to the glioma immune microenvironment. In this study, we demonstrate that the canonical 28SrRNA methyltransferase NSUN5 down-regulates ß-catenin by promoting the degradation of its mRNA, leading to enhanced phagocytosis of tumor-associated macrophages (TAMs). Specifically, the NSUN5-induced suppression of ß-catenin relies on its methyltransferase activity mediated by cysteine 359 (C359) and is not influenced by its localization in the nucleolus. Intriguingly, NSUN5 directly interacts with and deposits m5C on CTNNB1 caRNA (chromatin-associated RNA). NSUN5-induced recruitment of TET2 to chromatin is independent of its methyltransferase activity. The m5C modification on caRNA is subsequently oxidized into 5-hydroxymethylcytosine (5hmC) by TET2, which is dependent on its binding affinity for Fe2+ and α-KG. Furthermore, NSUN5 enhances the chromatin recruitment of RBFOX2 which acts as a 5hmC-specific reader to recognize and facilitate the degradation of 5hmC caRNA. Notably, hmeRIP-seq analysis reveals numerous mRNA substrates of NSUN5 that potentially undergo this mode of metabolism. In addition, NSUN5 is epigenetically suppressed by DNA methylation and is negatively correlated with IDH1-R132H mutation in glioma patients. Importantly, pharmacological blockage of DNA methylation or IDH1-R132H mutant and CD47/SIRPα signaling synergistically enhances TAM-based phagocytosis and glioma elimination in vivo. Our findings unveil a general mechanism by which NSUN5/TET2/RBFOX2 signaling regulates RNA metabolism and highlight NSUN5 targeting as a potential strategy for glioma immune therapy.

A comprehensive analysis of CD47 expression in various histological subtypes of soft tissue sarcoma: exploring novel opportunities for macrophage-directed treatments.

PURPOSE: The CD47 molecule, often referred to as the "do not eat me" signal, is frequently overexpressed in tumor cells. This signaling pathway limits phagocytosis by macrophages. Our objective was to determine CD47 abundance in various soft tissue sarcomas (STS) to investigate whether it could serve as a potential evasion mechanism for tumor cells. Additionally, we aimed to assess the prognostic value of CD47 expression by examining its association with different clinicopathological factors. This study aimed to elucidate the significance of CD47 in the context of emerging anti-tumor targeting approaches. METHODS: In this retrospective study, formalin-fixed paraffine-embedded (FFPE) tumor tissues of 55 treatment-naïve patients were evaluated by immunohistochemistry for the abundance of CD47 molecule on tumor cells. The categorization of CD47 positivity was as follows: 0 (no staining of tumor cells), 1 + (less than 1/3 of tumor area positive), 2 + (between 1/3 and 2/3 of tumor area positive), and 3 + (more than 2/3 of tumor area positive for CD47). Next, we compared CD47 abundance between different tumor grades (G1-3). We used Kaplan-Meier survival curves with log-rank test to analyze the differences in survival between patients with different CD47 expression. Moreover, we performed Cox proportional hazards regression model to evaluate the clinical significance of CD47. RESULTS: CD47 is widely prevalent across distinct STS subtypes. More than 80% of high grade undifferentiated pleiomorphic sarcoma (UPS), 70% of myxofibrosarcoma (MFS) and more than 60% of liposarcoma (LPS) samples displayed a pattern of moderate-to-diffuse positivity. This phenomenon remains consistent regardless of the tumor grade. However, there was a tendency for higher CD47 expression levels in the G3 group compared to the combined G1 + G2 groups when all LPS, MFS, and UPS were analyzed together. No significant associations were observed between CD47 abundance, death, and metastatic status. Additionally, high CD47 expression was associated with a statistically significant increase in progression-free survival in the studied cohort of patients. CONCLUSION: This study highlights the potential of the CD47 molecule as a promising immunotherapeutic target in STS, particularly given its elevated expression levels in diverse sarcoma types. Our data showed a notable trend linking CD47 expression to tumor grade, while also suggesting an interesting correlation between enhanced abundance of CD47 expression and a reduced hazard risk of disease progression. Although these findings shed light on different roles of CD47 in STS, further research is crucial to assess its potential in clinical settings.

Gentulizumab, a novel anti-CD47 antibody with potent antitumor activity and demonstrates a favorable safety profile.

BACKGROUND: Targeting CD47/SIRPα axis has emerged as a promising strategy in cancer immunotherapy. Despite the encouraging clinical efficacy observed in hematologic malignancies through CD47-SIRPα blockade, there are safety concerns related to the binding of anti-CD47 antibodies to CD47 on the membrane of peripheral blood cells. METHODS: In order to enhance the selectivity and therapeutic efficacy of the antibody, we developed a humanized anti-CD47 monoclonal antibody called Gentulizumab (GenSci059). The binding capacity of GenSci059 to CD47 was evaluated using flow cytometry and surface plasmon resonance (SPR) methods, the inhibitory effect of GenSci059 on the CD47-SIRPα interaction was evaluated through competitive ELISA assays. The anti-tumor activity of GenSci059 was assessed using in vitro macrophage models and in vivo patient-derived xenograft (PDX) models. To evaluate the safety profile of GenSci059, binding assays were conducted using blood cells. Additionally, we investigated the underlying mechanisms contributing to the weaker binding of GenSci059 to erythrocytes. Finally, toxicity studies were performed in non-human primates to assess the potential risks associated with GenSci059. RESULTS: GenSci059 displayed strong binding to CD47 in both human and monkey, and effectively inhibited the CD47-SIRPα interaction. With doses ranging from 5 to 20 mg/kg, GenSci059 demonstrated potent inhibition of the growth of subcutaneous tumor with the inhibition rates ranged from 30.3% to complete regression. Combination of GenSci059 with 2.5 mg/kg Rituximab at a dose of 2.5 mg/kg showed enhanced tumor inhibition compared to monotherapy, exhibiting synergistic effects. GenSci059 exhibited minimal binding to hRBCs compared to Hu5F9-G4. The binding of GenSci059 to CD47 depended on the cyclization of N-terminal pyroglutamic acid and the spatial conformation of CD47, but was not affected by its glycosylation modifications. A maximum tolerated dose (MTD) of 450 mg/kg was observed for GenSci059, and no significant adverse effects were observed in repeated dosages up to 10 + 300 mg/kg, indicating a favorable safety profile. CONCLUSION: GenSci059 selectively binds to CD47, effectively blocks the CD47/SIRPα axis signaling pathway and enhances the phagocytosis effects of macrophages toward tumor cells. This monoclonal antibody demonstrates potent antitumor activity and exhibits a favorable safety profile, positioning it as a promising and effective therapeutic option for cancer.

Co-targeting CD47 and VEGF elicited potent anti-tumor effects in gastric cancer.

BACKGROUND: CD47, serving as an intrinsic immune checkpoint, has demonstrated efficacy as an anti-tumor target in hematologic malignancies. Nevertheless, the clinical relevance of CD47 in gastric cancer and its potential as a therapeutic target remains unclear. METHODS: The expression of CD47 in clinical gastric cancer tissues was assessed using immunohistochemistry and Western blot. Patient-derived cells were obtained from gastric cancer tissues and co-cultured with macrophages derived from human peripheral blood mononuclear cells. Flow cytometry analyses were employed to evaluate the rate of phagocytosis. Humanized patient-derived xenografts (Hu-PDXs) models were established to assess the efficacy of anti-CD47 immunotherapy or the combination of anti-CD47 and anti-VEGF therapy in treating gastric cancer. The infiltrated immune cells in the xenograft were analyzed by immunohistochemistry. RESULTS: In this study, we have substantiated the high expression of CD47 in gastric cancer tissues, establishing a strong association with unfavorable prognosis. Through the utilization of SIRPα-Fc to target CD47, we have effectively enhanced macrophage phagocytosis of PDCs in vitro and impeded the growth of Hu-PDXs. It is noteworthy that anti-CD47 immunotherapy has been observed to sustain tumor angiogenic vasculature, with a positive correlation between the expression of VEGF and CD47 in gastric cancer. Furthermore, the successful implementation of anti-angiogenic treatment has further augmented the anti-tumor efficacy of anti-CD47 therapy. In addition, the potent suppression of tumor growth, prevention of cancer recurrence after surgery, and significant prolongation of overall survival in Hu-PDX models can be achieved through the simultaneous targeting of CD47 and VEGF using the bispecific fusion protein SIRPα-VEGFR1 or by combining the two single-targeted agents. CONCLUSIONS: Our preclinical studies collectively offer substantiation that CD47 holds promise as a prospective target for gastric cancer, while also highlighting the potential of anti-angiogenic therapy to enhance tumor responsiveness to anti-CD47 immunotherapy.

Structural-functional diversity of CD47 proteoforms.

The ubiquitously expressed transmembrane glycoprotein CD47 participates in various important physiological cell functions, including phagocytosis, apoptosis, proliferation, adhesion, and migration, through interactions with its ligands, including the inhibitory receptor signal regulatory protein α (SIRPα), secreted glycoprotein thrombospondin-1 (TSP-1), and integrins. Elevated expression of CD47 is observed in a wide range of cancer cells as a mechanism for evading the immune system, blocking the interaction between the CD47 and SIRPα is the most advanced and promising therapeutic approach currently investigated in multiple clinical trials. The widely held view that a single type of CD47 protein acts through membrane interactions has been challenged by the discovery of a large cohort of CD47 proteins with cell-, tissue-, and temporal-specific expression and functional profiles. These profiles have been derived from a single gene through alternative splicing and post-translational modifications, such as glycosylation, pyroglutamate modification, glycosaminoglycan modification, and proteolytic cleavage and, to some extent, via specific CD47 clustering in aging and tumor cells and the regulation of its subcellular localization by a pre-translational modification, alternative cleavage and polyadenylation (APA). This review explores the origins and molecular properties of CD47 proteoforms and their roles under physiological and pathological conditions, mentioning the new methods to improve the response to the therapeutic inhibition of CD47-SIRPα immune checkpoints, contributing to the understanding of CD47 proteoform diversity and identification of novel clinical targets and immune-related therapeutic candidates.

Glutamine inhibition combined with CD47 blockade enhances radiotherapy-induced ferroptosis in head and neck squamous cell carcinoma.

Head and neck squamous cell carcinoma (HNSCC) is a formidable cancer type that poses significant treatment challenges, including radiotherapy (RT) resistance. The metabolic characteristics of tumors present substantial obstacles to cancer therapy, and the relationship between RT and tumor metabolism in HNSCC remains elusive. Ferroptosis is a type of iron-dependent regulated cell death, representing an emerging disease-modulatory mechanism. Here, we report that after RT, glutamine levels rise in HNSCC, and the glutamine transporter protein SLC1A5 is upregulated. Notably, blocking glutamine significantly enhances the therapeutic efficacy of RT in HNSCC. Furthermore, inhibition of glutamine combined with RT triggers immunogenic tumor ferroptosis, a form of nonapoptotic regulated cell death. Mechanistically, RT increases interferon regulatory factor (IRF) 1 expression by activating the interferon signaling pathway, and glutamine blockade augments this efficacy. IRF1 drives transferrin receptor expression, elevating intracellular Fe2+ concentration, disrupting iron homeostasis, and inducing cancer cell ferroptosis. Importantly, the combination treatment-induced ferroptosis is dependent on IRF1 expression. Additionally, blocking glutamine combined with RT boosts CD47 expression and hinders macrophage phagocytosis, attenuating the treatment effect. Dual-blocking glutamine and CD47 promote tumor remission and enhance RT-induced ferroptosis, thereby ameliorating the tumor microenvironment. Our work provides valuable insights into the metabolic and immunological mechanisms underlying RT-induced ferroptosis, highlighting a promising strategy to augment RT efficacy in HNSCC.

Smart exosomes enhance PDAC targeted therapy.

Exosomes continue to attract interest as a promising nanocarrier drug delivery technology. They are naturally derived nanoscale extracellular vesicles with innate properties well suited to shuttle proteins, lipids, and nucleic acids between cells. Nonetheless, their clinical utility is currently limited by several major challenges, such as their inability to target tumor cells and a high proportion of clearance by the mononuclear phagocyte system (MPS) of the liver and spleen. To overcome these limitations, we developed "Smart Exosomes" that co-display RGD and CD47p110-130 through CD9 engineering (ExoSmart). The resultant ExoSmart demonstrates enhanced binding capacity to αvß3 on pancreatic ductal adenocarcinoma (PDAC) cells, resulting in amplified cellular uptake in in vitro and in vivo models and increased chemotherapeutic efficacies. Simultaneously, ExoSmart significantly reduced liver and spleen clearance of exosomes by inhibiting macrophage phagocytosis via CD47p110-130 interaction with signal regulatory proteins (SIRPα) on macrophages. These studies demonstrate that an engineered exosome drug delivery system increases PDAC therapeutic efficacy by enhancing active PDAC targeting and prolonging circulation times, and their findings hold tremendous translational potential for cancer therapy while providing a concrete foundation for future work utilizing novel peptide-engineered exosome strategies.

Quercetin Limits Tumor Immune Escape through PDK1/CD47 Axis in Melanoma.

Quercetin (3,3[Formula: see text],4[Formula: see text],5,7-pentahydroxyflavone) is a bioactive plant-derived flavonoid, abundant in fruits and vegetables, that can effectively inhibit the growth of many types of tumors without toxicity. Nevertheless, the effect of quercetin on melanoma immunology has yet to be determined. This study aimed to investigate the role and mechanism of the antitumor immunity action of quercetin in melanoma through both in vivo and in vitro methods. Our research revealed that quercetin has the ability to boost antitumor immunity by modulating the tumor immune microenvironment through increasing the percentages of M1 macrophages, CD8[Formula: see text] T lymphocytes, and CD4[Formula: see text] T lymphocytes and promoting the secretion of IL-2 and IFN-[Formula: see text] from CD8[Formula: see text] T cells, consequently suppressing the growth of melanoma. Furthermore, we revealed that quercetin can inhibit cell proliferation and migration of B16 cells in a dose-dependent manner. In addition, down-regulating PDK1 can inhibit the mRNA and protein expression levels of CD47. In the rescue experiment, we overexpressed PDK1 and found that the protein and mRNA expression levels of CD47 increased correspondingly, while the addition of quercetin reversed this effect. Moreover, quercetin could stimulate the proliferation and enhance the function of CD8[Formula: see text] T cells. Therefore, our results identified a novel mechanism through which CD47 is regulated by quercetin to promote phagocytosis, and elucidated the regulation of quercetin on macrophages and CD8[Formula: see text] T cells in the tumor immune microenvironment. The use of quercetin as a therapeutic drug holds potential benefits for immunotherapy, enhancing the efficacy of existing treatments for melanoma.

Discovery of a novel small molecule as CD47/SIRPα and PD-1/PD-L1 dual inhibitor for cancer immunotherapy.

BACKGROUND: Targeting the tumor microenvironment (TME) has emerged as a promising strategy in cancer treatment, particularly through the utilization of immune checkpoint blockade (ICB) agents such as PD-1/PD-L1 inhibitors. Despite partial success, the presence of tumor-associated macrophages (TAMs) contributes to an immunosuppressive TME that fosters tumor progression, and diminishes the therapeutic efficacy of ICB. Blockade of the CD47/SIRPα pathway has proven to be an effective intervention, that restores macrophage phagocytosis and yields substantial antitumor effects, especially when combined with PD-1/PD-L1 blockade. Therefore, the identification of small molecules capable of simultaneously blocking CD47/SIRPα and PD-1/PD-L1 interactions has remained imperative. METHODS: SMC18, a small molecule with the capacity of targeting both SIRPα and PD-L1 was obtained using MST. The efficiency of SMC18 in interrupting CD47/SIRPα and PD-1/PD-L1 interactions was tested by the blocking assay. The function of SMC18 in enhancing the activity of macrophages and T cells was tested using phagocytosis assay and co-culture assay. The antitumor effects and mechanisms of SMC18 were investigated in the MC38-bearing mouse model. RESULTS: SMC18, a small molecule that dual-targets both SIRPα and PD-L1 protein, was identified. SMC18 effectively blocked CD47/SIRPα interaction, thereby restoring macrophage phagocytosis, and disrupted PD-1/PD-L1 interactions, thus activating Jurkat cells, as evidenced by increased secretion of IL-2. SMC18 demonstrated substantial inhibition of MC38 tumor growths through promoting the infiltration of CD8+ T and M1-type macrophages into tumor sites, while also priming the function of CD8+ T cells and macrophages. Moreover, SMC18 in combination with radiotherapy (RT) further improved the therapeutic efficacy. CONCLUSION: Our findings suggested that the small molecule compound SMC18, which dual-targets the CD47/SIRPα and PD-1/PD-L1 pathways, could be a candidate for promoting macrophage- and T-cell-mediated phagocytosis and immune responses in cancer immunotherapy.

Tolerating CD47.

Cluster of differentiation 47 (CD47) occupies the outer membrane of human cells, where it binds to soluble and cell surface receptors on the same and other cells, sculpting their topography and resulting in a pleiotropic receptor-multiligand interaction network. It is a focus of drug development to temper and accentuate CD47-driven immune cell liaisons, although consideration of on-target CD47 effects remain neglected. And yet, a late clinical trial of a CD47-blocking antibody was discontinued, existent trials were restrained, and development of CD47-targeting agents halted by some pharmaceutical companies. At this point, if CD47 can be exploited for clinical advantage remains to be determined. Herein an airing is made of the seemingly conflicting actions of CD47 that reflect its position as a junction connecting receptors and signalling pathways that impact numerous human cell types. Prospects of CD47 boosting and blocking are considered along with potential therapeutic implications for autoimmune diseases and cancer.

MGMT unmethylation and high levels of CD47 and TIGIT indicate a poor prognosis in adult diffuse gliomas.

Introduction: In 2021, the World Health Organization published a new classification system for central nervous system tumors. This study reclassified the adult diffuse glioma (ADG) into astrocytoma, oligodendroglioma, and glioblastoma (GBM) according to the new tumor classification. Methods: The association of TERT promoter (pTERT) mutation, MGMT methylation, and CD47/TIGIT expression with patient prognosis was investigated. Results: Immunohistochemical analysis showed that the expression levels of CD47 and TIGIT in tumor tissues were significantly higher than those in normal brain tissues. CD47 levels were higher in GBM and grade 4 astrocytoma tissues. TIGIT expression was also higher in patients with GBM. The high expressions of CD47, TIGIT, and CD47/TIGIT were positively correlated with MGMT unmethylation but not pTERT mutation. Moreover, MGMT unmethylation was associated with poor overall survival in astrocytoma. High CD47, TIGIT, and CD47/TIGIT levels were associated with significantly reduced survival in ADG and GBM. GBM, MGMT unmethylation, and high CD47 expression were independent prognostic factors for overall survival in ADG. Discussion: Collectively, these results showed that the MGMT unmethylation and high levels of CD47 and TIGIT are associated with a poor prognosis in ADG. Patients with high CD47 and TIGIT expression may benefit from anti-CD47 and TIGIT immunotherapy.

CC-96673 (BMS-986358), an affinity-tuned anti-CD47 and CD20 bispecific antibody with fully functional fc, selectively targets and depletes non-Hodgkin's lymphoma.

Cluster of differentiation 47 (CD47) is a transmembrane protein highly expressed in tumor cells that interacts with signal regulatory protein alpha (SIRPα) and triggers a "don't eat me" signal to the macrophage, inhibiting phagocytosis and enabling tumor escape from immunosurveillance. The CD47-SIRPα axis has become an important target for cancer immunotherapy. To date, the advancement of CD47-targeted modalities is hindered by the ubiquitous expression of the target, often leading to rapid drug elimination and hematologic toxicity including anemia. To overcome those challenges a bispecific approach was taken. CC-96673, a humanized IgG1 bispecific antibody co-targeting CD47 and CD20, is designed to bind CD20 with high affinity and CD47 with optimally lowered affinity. As a result of the detuned CD47 affinity, CC-96673 selectively binds to CD20-expressing cells, blocking the interaction of CD47 with SIRPα. This increased selectivity of CC-96673 over monospecific anti-CD47 approaches allows for the use of wild-type IgG1 Fc, which engages activating crystallizable fragment gamma receptors (FcγRs) to fully potentiate macrophages to engulf and destroy CD20+ cells, while sparing CD47+CD20- normal cells. The combined targeting of anti-CD20 and anti-CD47 results in enhanced anti- tumor activity compared to anti-CD20 targeting antibodies alone. Furthermore, preclinical studies have demonstrated that CC-96673 exhibits acceptable pharmacokinetic properties with a favorable toxicity profile in non-human primates. Collectively, these findings define CC-96673 as a promising CD47 × CD20 bispecific antibody that selectively destroys CD20+ cancer cells via enhanced phagocytosis and other effector functions.

Restoration of miR-299-3p promotes macrophage phagocytosis and suppresses malignant phenotypes in breast cancer carcinogenesis via dual-targeting CD47 and ABCE1.

Immunoevasion has been a severe obstacle for the clinical treatment of breast cancer (BC). CD47, known as an anti-phagocytic molecule, plays a key role in governing the evasion of tumor cells from immune surveillance by interacting with signal-regulated protein α (SIRPα) on macrophages. Here, we report for the first time that miR-299-3p is a direct regulator of CD47 with tumor suppressive effects both in vitro and in vivo. miRNA expression profiles and overall survival of BC cohorts from the Cancer Genome Atlas, METABRIC, or GSE19783 datasets showed that miR-299-3p is downregulated in BC tissues and that BC patients with low levels of miR-299-3p have poorer prognoses. Using dual-luciferase reporter, qRT-PCR, Western blot, and phagocytosis assays, we proved that restoration of miR-299-3p can suppress CD47 expression by directly targeting the predicted seed sequence "CCCACAU" in its 3'-UTR, leading to phagocytosis of BC cells by macrophages, whereas miR-299-3p inhibition or deletion reversed this effect. Additionally, Gene Ontology (GO) analysis and a variety of confirmatory experiments revealed that miR-299-3p was inversely correlated with cell proliferation, migration, and the cell cycle process. Mechanistically, miR-299-3p can also directly target ABCE1, an essential ribosome recycling factor, alleviating these malignant phenotypes of BC cells. In vivo BC xenografts based on nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice further proved that restoration of miR-299-3p resulted in a significant suppression of tumorigenesis and a promotion of macrophage activation and infiltration. Overall, our study suggested that miR-299-3p is a potent inhibitor of CD47 and ABCE1 to exhibit bifunctional BC-suppressing effects through immune activation conjugated with malignant behavior inhibition in breast carcinogenesis and thus can potentially serve as a novel therapeutic target for BC.

CD47-a novel prognostic predicator in epithelial ovarian cancer and correlations with clinicopathological and gene mutation features.

BACKGROUND: Epithelial ovarian cancer (EOC) is insensitive to immunotherapy due to its poor immunogenicity; thus, suitable biomarkers need to be identified for better prognostic stratification and individualized treatment. CD47 is a novel immunotherapy target; however, its impact on EOC prognosis is controversial and correlation with genetic features is unclear. The aim of this study was to investigate the prognostic significance of CD47 and its correlations with biological behaviors and genetic features of EOC. METHODS: Immunohistochemistry (IHC) and next-generation sequencing (NGS) were performed to examine expressions of CD47, PD-L1, and genomic mutations in the tissue samples of 75 EOC patients. Various clinicopathologic and genomic features were then evaluated to determine their correlation with CD47 expression. Kaplan-Meier analysis and Cox regression analysis were used to identify independent prognostic factors. Risk score modeling was then established, and the predictive capacity of this model was further confirmed by nomogram analysis. RESULTS: CD47 was mainly expressed in the tumor cell membrane and cytoplasm, and the rate of high CD47 expression was 63.7%. CD47 expression was associated with various clinicopathological factors, including FIGO stage, CA125 and HE4 value, presence of multidisciplinary surgeries, presence and volume of ascites, lymph-node metastasis, Ki-67 index and platinum-resistant, as well as genetic characteristics like BRCA mutation, HRD status, and TP53 mutation in EOC. Patients with high CD47 expression showed worse prognosis than the low-expression group. Cox regression analysis demonstrated that CA125, CD47, and BRCA mutation were independent factors for EOC prognosis. Patients were then categorized into high-risk and low-risk subgroups based on the risk score of the aforementioned independent factors, and the prognosis of the high-risk group was worse than those of the low-risk group. The nomogram showed adequate discrimination with a concordance index of 0.777 (95% CI, 0.732-0.822). The calibration curve showed good consistency. CONCLUSION: CD47 correlated with various malignant biology and genetic characteristics of EOC and may play pivotal and multifaceted roles in the tumor microenvironment of EOC Finally, we constructed a reliable prediction model centered on CD47 and integrated CA125 and BRCA to better guide high-risk population management.