Mechanism of synergy between T cell signals and C8-substituted guanine nucleosides in humoral immunity: B lymphotropic cytokines induce responsiveness to 8-mercaptoguanosine

Deciphering the IgG Idiotype Network Through Proteomic Analysis of Potential Targets in SARS-CoV-2-Induced Immune Responses

The association between COVID-19 and autoimmune diseases has gained increasing recognition, yet the specific targets of SARS-CoV-2-induced IgG are currently in focus for several studies. This study aims to explore the proteomic targets of these antibodies and their potential role in autoimmunity. We utilised a human proteome microarray encompassing 23 736 unique proteins, including isoform variants and fragments, as catalogued by the Human Protein Atlas. Serum samples were analysed from four groups: healthy controls (N-exp HC), individuals vaccinated with protein-based vaccines (N-Cov Vac) and patients with moderate or severe COVID-19 (COVID-Mod and COVID-Sev). The evaluation of SARS-CoV-2-induced IgG antibodies revealed their potential to recognise multiple human proteins. Key targets included interferon alpha (IFN-α), tumour growth factor beta (TGF-β), interleukin 1 (IL-1), CXCL16, TGF-β receptors, CD34, CD47 and BCL2. The antibodies also targeted proteins from genes overexpressed in various immune cells, such as CD4+ and CD8+ T cells, γδ T cells, B cells, dendritic cells and NK cells. Reactivity was also observed with proteins specifically expressed in multiple organs, including the brain, liver, lungs and heart. Targeting patterns differed between COVID-19 patients and controls, with some proteins showing differential recognition in moderate versus severe cases. Furthermore, we evaluated the protein-protein interaction network (PPIN) of all targeted proteins and observed minimal structural homology and co-expression among the evaluated proteins, with almost no relation to the SARS-CoV-2 immune system reactome. The results suggest that the profile of SARS-CoV-2-induced IgG autoantibodies is associated with disease severity. In contrast, protein-vaccinated individuals exhibited a profile similar to non-exposed controls, suggesting that autoreactive IgG is specifically linked to active SARS-CoV-2 infection. These findings reveal a complex network of SARS-CoV-2-induced IgG idiotypes capable of targeting human proteins, not merely through simple cross-recognition of homologous proteins. This highlights the need for further investigations to determine whether they may influence COVID-19 pathophysiology and its clinical outcomes.

CD47 as a potent target in cancer immunotherapy: A review

Cancer is the second-highest cause of death worldwide. Accordingly, finding new cancer treatments is of great interest to researchers. The current platforms to fight cancer such as chemotherapy, radiotherapy, and surgery are limited in efficacy, especially in the metastatic setting. In this war against cancer, the immune system is a powerful ally, but tumor cells often outsmart it through alternative pathways. Cluster of differentiation 47 (CD47), a protein that normally prevents healthy cells from being attacked by immune cells, is often overexpressed on cancer cells. This makes CD47 a prime target for immunotherapy. Blocking of CD47 has the potential to unleash the immune system's cell populations-such as myeloid cells, macrophages, and T cells-to allow the immune system to discover and destroy cancer cells more successfully. In this review, we aimed to provide the latest information and findings about the roles of CD47 in the regulation of various cellular pathways and, thus, the importance of CD47 as a potential target in cancer therapy.

Post-translational modifications of immune checkpoints: unlocking new potentials in cancer immunotherapy

Immunotherapy targeting immune checkpoints has gained traction across various cancer types in clinical settings due to its notable advantages. Despite this, the overall response rates among patients remain modest, alongside issues of drug resistance and adverse effects. Hence, there is a pressing need to enhance immune checkpoint blockade (ICB) therapies. Post-translational modifications (PTMs) are crucial for protein functionality. Recent research emphasizes their pivotal role in immune checkpoint regulation, directly impacting the expression and function of these key proteins. This review delves into the influence of significant PTMs-ubiquitination, phosphorylation, and glycosylation-on immune checkpoint signaling. By targeting these modifications, novel immunotherapeutic strategies have emerged, paving the way for advancements in optimizing immune checkpoint blockade therapies in the future.

Ezrin works as a scaffold protein for a macrophage checkpoint molecule CD47, leading to a poor prognosis for patients with uterine cervical squamous cell carcinoma

OBJECTIVES

Despite recent advances in the immunotherapeutic intervention as the second-line treatment of cervical cancer, including Pembrolizumab and Nivolumab, the advanced stages of the disease are still associated with poor prognosis. CD47 is a macrophage checkpoint molecule overexpressed superficially in nearly all cancer types that binds to its receptor on macrophage surface, leading to a disruption of their phagocytic capacities against cancer cells. Ezrin-Radixin-Moesin (ERM) family member of proteins work as scaffold proteins by crosslinking specific transmembrane proteins to actin filaments, contributing to their plasma membrane localization. This study aimed to investigate the relationship between ERM family and CD47 in the uterine cervical squamous cell carcinoma (UCSCC).

MATERIALS AND METHODS

The mRNA expression, intracellular localization, and molecular interaction of CD47 and ERM in BOKU cells derived from human UCSCC were determined using RT-PCR, immunofluorescence, and co-immunoprecipitation, respectively. CD47 plasma membrane expression was measured by flow cytometry three days after transfection with small interfering RNAs against each ERM. CD47 and ERM expression in tumor tissues from patients with uterine cervical cancer was analyzed using a clinical RNA sequencing database.

RESULTS

Confocal laser scanning microscopy analysis showed the co-localization of CD47 with all three ERM in the plasma membrane of BOKU cells. RNA interference-mediated knockdown of ezrin but not others reduced the plasma membrane expression of CD47. Furthermore, immunoprecipitation assay demonstrated the molecular interaction of CD47 with ezrin. Notably, bioinformatic analysis indicated that CD47 and ezrin expressions were markedly increased and positively correlated in the clinical uterine cervical tumor tissues and that higher expressions of ezrin correlates with a poor prognosis for the uterine cervical cancers.

CONCLUSION

This study illustrates that in uterine cervical cancers, ezrin may be a dominant scaffold protein responsible for CD47 expression and, therefore, is a potential target for developing a novel macrophage checkpoint blockade therapy.

Cell Membrane Camouflaged Biomimetic Nanoparticles as a Versatile Platform for Brain Diseases Treatment

Although there are various advancements in biomedical in the past few decades, there are still challenges in the treatment of brain diseases. The main difficulties are the inability to deliver a therapeutic dose of the drug to the brain through the blood-brain barrier (BBB) and the serious side effects of the drug. Thus, it is essential to select biocompatible drug carriers and novel therapeutic tools to better enhance the effect of brain disease treatment. In recent years, biomimetic nanoparticles (BNPs) based on natural cell membranes, which have excellent biocompatibility and low immunogenicity, are widely used in the treatment of brain diseases to enable the drug to successfully cross the BBB and target brain lesions. BNPs can prolong the circulation time in vivo, are more conducive to drug aggregation in brain lesions. Cell membranes (CMs) from cancer cells (CCs), red blood cells (RBCs), white blood cells (WBCs), and so on are used as biomimetic coatings for nanoparticles (NPs) to achieve the ability to target, evade clearance, or stimulate the immune system. This review summarizes the application of different cell sources as BNPs coatings in the treatment of brain diseases and discusses the possibilities and challenges of clinical translation.

NRF-1 transcription factor regulates expression of an innate immunity checkpoint, CD47, during melanomagenesis

Transmembrane integrin-associated protein CD47 functions as a potent innate immunity checkpoint and is upregulated by many types of malignant cells, including melanoma during tumor progression. Binding of CD47 to its target receptor, SIRPα, on myeloid cell lineages leads to the initiation of the downstream signaling cascades that inhibit innate immunity anti-tumor responses. Molecular mechanisms underlying upregulation of CD47 during melanoma progression remain largely unknown. In this report, we performed ATAC-Sequencing on patient-derived melanoma cells, as well as, the analysis of ATAC-Seq datasets covering clinical melanoma samples to demonstrate a significant increase in chromatin accessibility for the CD47 promoter region in comparison to normal cells and tissues. Additionally, profiling of multiple CD47 transcript isoforms established that upregulation of CD47 in malignant cells occurs at the mRNA level. Using chromatin immunoprecipitation (ChIP) approaches along with the analysis of ChIP-Seq cancer datasets, we identified the transcription factor NRF-1 which binds at multiple sites within the proximal CD47 promoter region. In combination with serial deletions of CD47 promoter, we defined the minimal DNA region required for its activation, as well as, specific DNA locations within that region, which are preferentially occupied by NRF-1 in tumor cells.

Facilitating cholangiocarcinoma inhibition by targeting CD47

Immune evasion is one of the mechanisms by which cancer cells acquire immunity during cancer development and progression. One of these is the increased expression of cluster of differentiation 47 (CD47), a transmembrane glycoprotein that protects cells from phagocytic elimination. The interaction between CD47 and signal regulatory protein alpha (SIRPα) on macrophages alleviates the phagocytic signal. The present group previously reported high CD47 expression in cholangiocarcinoma (CCA), a major health problem in Thailand and East Asia, and that blocking CD47 using anti-CD47 antibodies promoted the removal of CCA. However, the mechanism through which CD47 inhibition attenuates CCA growth remains unclear. This study explored the clinical significance of targeting CD47 in CCA. Expression levels of CD47 and the macrophage marker CD68 were determined in CCA tissues by immunohistochemistry and correlated with clinical parameters. The role of CD47 in CCA cells was established using CD47-deficient KKU-213A CCA clones in vitro and in vivo. The results showed that CD47 was highly expressed in CCA tissues and significantly correlated with lymph node metastasis (P = 0.038). Moderate-to-dense CD68-positive infiltrating cells in CCA tissues were significantly associated with shorter survival of patients (P = 0.019) and were an independent prognostic factor of CCA patients as determined by the Cox proportional hazard model (hazard ratio, 2.040; 95 % confidence interval, 1.109-3.752; P = 0.022). Three CD47-deficient KKU-213A clones (#19, #23, and #28) were generated. The elimination of CD47 did not affect cell proliferation but increased monocyte-derived macrophage-mediated phagocytosis in vitro. Decreased tumor weights and volumes were observed in mice injected with CD47-deficient CCA clones. This revealed a significant role for CD47 in CCA, with a focus on protecting cancer cells from macrophage phagocytosis.

Intravenous Administration of Anti-CD47 Antibody Augments Hematoma Clearance, Mitigates Acute Neuropathology, and Improves Cognitive Function in a Rat Model of Penetrating Traumatic Brain Injury

Traumatic brain injury (TBI)-induced intracerebral hematoma is a major driver of secondary injury pathology such as neuroinflammation, cerebral edema, neurotoxicity, and blood-brain barrier dysfunction, which contribute to neuronal loss, motor deficits, and cognitive impairment. Cluster of differentiation 47 (CD47) is an antiphagocytic cell surface protein inhibiting hematoma clearance. This study was designed to evaluate the safety and efficacy of blockade of CD47 via intravenous (i.v.) administration of anti-CD47 antibodies following penetrating ballistic-like brain injury (PBBI) with significant traumatic intracerebral hemorrhage (tICH). The pharmacokinetic (PK) profile of the anti-CD47 antibody elicited that antibody concentration decayed over 7 days post-administration. Blood tests and necropsy analysis indicated no severe adverse events following treatment. Cerebral hemoglobin levels were significantly increased after injury, however, anti-CD47 antibody administration at 0.1 mg/kg resulted in a significant reduction in cerebral hemoglobin levels at 72 h post-administration, indicating augmentation of hematoma clearance. Immunohistochemistry assessment of glial fibrillary acidic protein (GFAP) and ionized calcium-binding adaptor molecule 1 (IBA1) demonstrated a significant reduction of GFAP levels in the lesion core and peri-lesional area. Based on these analyses, the optimal dose was identified as 0.1 mg/kg. Lesion volume showed a reduction following treatment. Rotarod testing revealed significant motor deficits in all injured groups but no significant therapeutic benefits. Spatial learning performance revealed significant deficits in all injured groups, which were significantly improved by the last testing day. Anti-CD47 antibody treated rats showed significantly improved attention deficits, but not retention scores. These results provide preliminary evidence that blockade of CD47 using i.v. administration of anti-CD47 antibodies may serve as a potential therapeutic for TBI with ICH.

Beyond resorption: osteoclasts as drivers of bone formation

Emerging evidence illustrates that osteoclasts (OCs) play diverse roles beyond bone resorption, contributing significantly to bone formation and regeneration. Despite this, OCs remain mysterious cells, with aspects of their lifespan-from origin, fusion, alterations in cellular characteristics, to functions-remaining incompletely understood. Recent studies have identified that embryonic osteoclastogenesis is primarily driven by osteoclast precursors (OCPs) derived from erythromyeloid progenitors (EMPs). These precursor cells subsequently fuse into OCs essential for normal bone development and repair. Postnatally, hematopoietic stem cells (HSCs) become the primary source of OCs, gradually replacing EMP-derived OCs and assuming functional roles in adulthood. The absence of OCs during bone development results in bone structure malformation, including abnormal bone marrow cavity formation and shorter long bones. Additionally, OCs are reported to have intimate interactions with blood vessels, influencing bone formation and repair through angiogenesis regulation. Upon biomaterial implantation, activation of the innate immune system ensues immediately. OCs, originating from macrophages, closely interact with the immune system. Furthermore, evidence from material-induced bone formation events suggests that OCs are pivotal in these de novo bone formation processes. Nevertheless, achieving a pure OC culture remains challenging, and interpreting OC functions in vivo faces difficulties due to the presence of other multinucleated cells around bone-forming biomaterials. We here describe the fusion characteristics of OCPs and summarize reliable markers and morphological changes in OCs during their fusion process, providing guidance for researchers in identifying OCs both in vitro and in vivo. This review focuses on OC formation, characterization, and the roles of OCs beyond resorption in various bone pathophysiological processes. Finally, therapeutic strategies targeting OCs are discussed.

Advancing cancer immunotherapy through siRNA-based gene silencing for immune checkpoint blockade

Cancer immunotherapy represents a revolutionary strategy, leveraging the patient's immune system to inhibit tumor growth and alleviate the immunosuppressive effects of the tumor microenvironment (TME). The recent emergence of immune checkpoint blockade (ICB) therapies, particularly following the first approval of cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors like ipilimumab, has led to significant growth in cancer immunotherapy. The extensive explorations on diverse immune checkpoint antibodies have broadened the therapeutic scope for various malignancies. However, the clinical response to these antibody-based ICB therapies remains limited, with less than 15% responsiveness and notable adverse effects in some patients. This review introduces the emerging strategies to overcome current limitations of antibody-based ICB therapies, mainly focusing on the development of small interfering ribonucleic acid (siRNA)-based ICB therapies and innovative delivery systems. We firstly highlight the diverse target immune checkpoint genes for siRNA-based ICB therapies, incorporating silencing of multiple genes to boost anti-tumor immune responses. Subsequently, we discuss improvements in siRNA delivery systems, enhanced by various nanocarriers, aimed at overcoming siRNA's clinical challenges such as vulnerability to enzymatic degradation, inadequate pharmacokinetics, and possible unintended target interactions. Additionally, the review presents various combination therapies that integrate chemotherapy, phototherapy, stimulatory checkpoints, ICB antibodies, and cancer vaccines. The important point is that when used in combination with siRNA-based ICB therapy, the synergistic effect of traditional therapies is strengthened, improving host immune surveillance and therapeutic outcomes. Conclusively, we discuss the insights into innovative and effective cancer immunotherapeutic strategies based on RNA interference (RNAi) technology utilizing siRNA and nanocarriers as a novel approach in ICB cancer immunotherapy.

Autophagy-Dependent Secretion: Crosstalk between Autophagy and Exosome Biogenesis

The cellular secretome is pivotal in mediating intercellular communication and coordinating responses to stressors. Exosomes, initially recognized for their role in waste disposal, have now emerged as key intercellular messengers with significant therapeutic and diagnostic potential. Similarly, autophagy has transcended its traditional role as a waste removal mechanism, emerging as a regulator of intracellular communication pathways and a contributor to a unique autophagy-dependent secretome. Secretory authophagy, initiated by various stress stimuli, prompts the selective release of proteins implicated in inflammation, including leaderless proteins that bypass the conventional endoplasmic reticulum-Golgi secretory pathway. This reflects the significant impact of stress-induced autophagy on cellular secretion profiles, including the modulation of exosome release. The convergence of exosome biogenesis and autophagy is exemplified by the formation of amphisomes, vesicles that integrate autophagic and endosomal pathways, indicating their synergistic interplay. Regulatory proteins common to both pathways, particularly mTORC1, emerge as potential therapeutic targets to alter cellular secretion profiles involved in various diseases. This review explores the dynamic interplay between autophagy and exosome formation, highlighting the potential to influence the secretome composition. While the modulation of exosome secretion and cytokine preconditioning is well-established in regenerative medicine, the strategic manipulation of autophagy is still underexplored, presenting a promising but uncharted therapeutic landscape.

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.

Discovery and Preclinical Activity of BMS-986351, an Antibody to SIRPα That Enhances Macrophage-mediated Tumor Phagocytosis When Combined with Opsonizing Antibodies

In normal cells, binding of the transmembrane protein CD47 to signal regulatory protein-α (SIRPα) on macrophages induces an antiphagocytic signal. Tumor cells hijack this pathway and overexpress CD47 to evade immune destruction. Macrophage antitumor activity can be restored by simultaneously blocking the CD47-SIRPα signaling axis and inducing a prophagocytic signal via tumor-opsonizing antibodies. We identified a novel, fully human mAb (BMS-986351) that binds SIRPα with high affinity. BMS-986351 demonstrated broad binding coverage across SIRPα polymorphisms and potently blocked CD47-SIRPα binding at the CD47 binding site in a dose-dependent manner. In vitro, BMS-986351 increased phagocytic activity against cell lines from solid tumors and hematologic malignancies, and this effect was markedly enhanced when BMS-986351 was combined with the opsonizing antibodies cetuximab and rituximab. A phase I dose-escalation/-expansion study of BMS-986351 for the treatment of advanced solid and hematologic malignancies is underway (NCT03783403).

SIGNIFICANCE

Increasing the phagocytotic capabilities of tumor-associated macrophages by modulating macrophage-tumor cell surface signaling via the CD47-SIRPα axis is a novel strategy. Molecules targeting CD47 have potential but its ubiquitous expression necessitates higher therapeutic doses to overcome potential antigen sink effects. The restricted expression pattern of SIRPα may limit toxicities and lower doses of the SIRPα antibody BMS-986351 may overcome target mediated drug disposition while maintaining the desired pharmacology.

Dual Role of Vitamin C-Encapsulated Liposomal Berberine in Effective Colon Anticancer Immunotherapy

The aim of the study was to achieve effective colon anticancer immunotherapy using the alkaloid berberine. In the presented paper we attempt to develop a formulation of berberine loaded into liposomal carriers using the vitamin C gradient method, characterized by efficient drug encapsulation, high stability during long-term storage, low drug release in human plasma with specific cytotoxicity towards colon cancer cells. Liposomal berberine was responsible for the induction of oxidative stress, the presence of Ca2+ ions in the cytosol, the reduction of Δψm, and ATP depletion with a simultaneous lack of caspase activity. Moreover, treatment with liposomal berberine led to CRT exposure on the surface of cancer cells, extracellular ATP, and HMGB1 release. The above-described mechanism of action was most likely associated with ICD induction, contributing to the increased number of phagocytic cancer cells. We have shown that cancer cells treated with liposomal berberine were phagocytosed more frequently by macrophages compared to the untreated cancer cells. What is more, we have shown that macrophage pre-treatment with liposomal berberine led to a 3-fold change in the number of phagocytosed SW620 cancer cells. The obtained results provide new insights into the role of berberine in maintaining the immune response against colorectal cancer.

Bosentan attenuates sickle cell disease erythrocyte HbS polymerization and impaired deformability induced by endothelin-1

The effects of endothelin-1 (ET-1) on erythrocytes from sickle cell disease (SCD) patients have been described, but mechanisms of ET-1 regarding primary erythrocyte functions remain unknown. ET-1 is a vasoconstrictor peptide produced by endothelial cells, and the expression of ET-1 is increased in SCD. The present study used ex vivo experiments with sickle cell erythrocytes, ET-1, and bosentan, a dual antagonist of ETA and ETB receptors. We performed a hemoglobin S (HbS) polymerization assay with three concentrations of ET-1 (1, 20, and 50 pg/mL) and bosentan (100 nmol/L). ET-1 increased HbS polymerization at all concentrations, and this effect was suppressed by bosentan. For the deformability assay, red blood cells (RBCs) were incubated on a Sephacryl column with the same concentrations of ET-1 and bosentan. ET-1 decreased deformability, and this effect was reversed by bosentan. To observe erythrocyte adhesion, ET-1 and bosentan were incubated with RBCs in thrombospondin-coated 96-well plate, which demonstrated that ET-1 decreased adhesion but that bosentan enhanced adhesion. We also assessed erythrocyte apoptosis and observed decreased eryptosis induced by ET-1, and these effects were inhibited bosentan. Thus, these findings demonstrated that ET-1 modulates HbS polymerization, erythrocyte deformability, adhesion to thrombospondin, and eryptosis, and these effects were suppressed or enhanced by bosentan.

CD47: The Next Frontier in Immune Checkpoint Blockade for Non-Small Cell Lung Cancer

The success of PD-1/PD-L1-targeted therapy in lung cancer has resulted in great enthusiasm for additional immunotherapies in development to elicit similar survival benefits, particularly in patients who do not respond to or are ineligible for PD-1 blockade. CD47 is an immunosuppressive molecule that binds SIRPα on antigen-presenting cells to regulate an innate immune checkpoint that blocks phagocytosis and subsequent activation of adaptive tumor immunity. In lung cancer, CD47 expression is associated with poor survival and tumors with EGFR mutations, which do not typically respond to PD-1 blockade. Given its prognostic relevance, its role in facilitating immune escape, and the number of agents currently in clinical development, CD47 blockade represents a promising next-generation immunotherapy for lung cancer. In this review, we briefly summarize how tumors disrupt the cancer immunity cycle to facilitate immune evasion and their exploitation of immune checkpoints like the CD47-SIRPα axis. We also discuss approved immune checkpoint inhibitors and strategies for targeting CD47 that are currently being investigated. Finally, we review the literature supporting CD47 as a promising immunotherapeutic target in lung cancer and offer our perspective on key obstacles that must be overcome to establish CD47 blockade as the next standard of care for lung cancer therapy.

Radixin modulates the plasma membrane localization of CD47 in human uterine cervical adenocarcinoma cells

Despite the dramatic success of immune checkpoint blockers in treating numerous cancer cell types, current therapeutic modalities provide clinical benefits to a subset of patients with cervical cancers. CD47 is commonly overexpressed in a broad variety of cancer cells, correlates with poor clinical prognosis, and acts as a dominant macrophage checkpoint by interacting with receptors expressed on macrophages. It allows cancer cells to escape from the innate immune system and hence is a potential therapeutic target for developing novel macrophage checkpoint blockade immunotherapies. As the intracellular scaffold proteins, ezrin/radixin/moesin (ERM) family proteins post-translationally regulate the cellular membrane localization of numerous transmembrane proteins, by crosslinking them with the actin cytoskeleton. We demonstrated that radixin modulates the plasma membrane localization and functionality of CD47 in HeLa cells. Immunofluorescence analysis and co-immunoprecipitation assay using anti-CD47 antibody showed the colocalization of CD47 and all three ERM families in the plasma membrane, and the molecular interactions between CD47 and all three ERM. Interestingly, gene silencing of only radixin, reduced the CD47 plasma membrane localization and functionality by means of flow cytometry and phagocytosis assay but had little influence on its mRNA expression. Together, in HeLa cells radixin may function as a principal scaffold protein responsible for the CD47 plasma membrane localization.

Circulating LPS from gut microbiota leverages stenosis-induced deep vein thrombosis in mice

OBJECTIVE AND DESIGN

An accumulating body of evidence has shown that gut microbiota is involved in regulating inflammation; however, it remains undetermined if and how gut microbiota plays an important role in modulating deep venous thrombosis (DVT), which is an inflammation-involved thrombotic event.

SUBJECTS

Mice under different treatments were used in this study.

METHODS AND TREATMENT

We induced stenosis DVT in mice by partially ligating the inferior vena cava. Mice were treated with antibiotics, prebiotics, probiotics, or inflammatory reagents to modulate inflammatory states, and their effects on the levels of circulating LPS and DVT were examined.

RESULTS

Antibiotic-treated mice or germ-free mice exhibited compromised DVT. Treatment of mice with either prebiotics or probiotics effectively suppressed DVT, which was accompanied with the downregulation of circulating LPS. Restoration of circulating LPS in these mice with a low dose of LPS was able to restore DVT. LPS-induced DVT was blocked by a TLR4 antagonist. By performing proteomic analysis, we identified TSP1 as one of the downstream effectors of circulating LPS in DVT.

CONCLUSION

These results suggest that gut microbiota may play a nonnegligible role in modulating DVT by leveraging the levels of LPS in circulation, thus shedding light on the development of gut microbiota-based strategies for preventing and treating DVT.

High-affinity decoy protein, nFD164, with an inactive Fc region as a potential therapeutic drug targeting CD47

CD47, as an innate immune checkpoint molecule, is an important target of cancer immunotherapy. We previously reported that a high-affinity SIRPα variant FD164 fused with IgG1 subtype Fc showed a better antitumor effect than wild-type SIRPα in an immunodeficient tumor-bearing model. However, CD47 is widely expressed in blood cells, and the drugs targeting CD47 may cause potential hematological toxicity. Herein, we modified the FD164 molecule by Fc mutation (N²⁹⁷A) to inactivate the Fc-related effector function and named it nFD164. Moreover, we further studied the potential of nFD164 as a candidate drug targeting CD47, including the stability, in vitro activity, antitumor activity of single or combined drugs in vivo, and hematological toxicity in humanized CD47/SIRPα transgenic mouse model. The results show that nFD164 maintains strong binding activity to CD47 on tumor cells, but has weak binding activity with red blood cells or white blood cells, and nFD164 has good drug stability under accelerated conditions (high temperature, bright light and freeze-thaw cycles). More importantly, in the immunodeficient or humanized CD47/SIRPα transgenic mice bearing tumor model, the combination of nFD164 and anti-CD20 antibody or anti-mPD-1 antibody had a synergistic antitumor effect. Especially in transgenic mouse models, nFD164 combined with anti-mPD-1 significantly enhanced tumor suppressive activity compared with anti-mPD-1 (P < 0.01) or nFD164 (P < 0.01) as a single drug and had fewer hematology-related side effects than FD164 or Hu5F9-G4. When these factors are taken together, nFD164 is a promising high-affinity CD47-targeting drug candidate with better stability, potential antitumor activity, and improved safety profile.

Multi-targeted immunotherapeutics to treat B cell malignancies

The concept of multi-targeted immunotherapeutic systems has propelled the field of cancer immunotherapy into an exciting new era. Multi-effector molecules can be designed to engage with, and alter, the patient's immune system in a plethora of ways. The outcomes can vary from effector cell recruitment and activation upon recognition of a cancer cell, to a multipronged immune checkpoint blockade strategy disallowing evasion of the cancer cells by immune cells, or to direct cancer cell death upon engaging multiple cell surface receptors simultaneously. Here, we review the field of multi-specific immunotherapeutics implemented to treat B cell malignancies. The mechanistically diverse strategies are outlined and discussed; common B cell receptor antigen targeting strategies are outlined and summarized; and the challenges of the field are presented along with optimistic insights for the future.

Self-assembling paclitaxel-mediated stimulation of tumor-associated macrophages for postoperative treatment of glioblastoma

The unique cancer-associated immunosuppression in brain, combined with a paucity of infiltrating T cells, contributes to the low response rate and poor treatment outcomes of T cell-based immunotherapy for patients diagnosed with glioblastoma multiforme (GBM). Here, we report on a self-assembling paclitaxel (PTX) filament (PF) hydrogel that stimulates macrophage-mediated immune response for local treatment of recurrent glioblastoma. Our results suggest that aqueous PF solutions containing aCD47 can be directly deposited into the tumor resection cavity, enabling seamless hydrogel filling of the cavity and long-term release of both therapeutics. The PTX PFs elicit an immune-stimulating tumor microenvironment (TME) and thus sensitizes tumor to the aCD47-mediated blockade of the antiphagocytic "don't eat me" signal, which subsequently promotes tumor cell phagocytosis by macrophages and also triggers an antitumor T cell response. As adjuvant therapy after surgery, this aCD47/PF supramolecular hydrogel effectively suppresses primary brain tumor recurrence and prolongs overall survivals with minimal off-target side effects.

Osteosarcoma-enriched transcripts paradoxically generate osteosarcoma-suppressing extracellular proteins

Osteosarcoma (OS) is the common primary bone cancer that affects mostly children and young adults. To augment the standard-of-care chemotherapy, we examined the possibility of protein-based therapy using mesenchymal stem cells (MSCs)-derived proteomes and OS-elevated proteins. While a conditioned medium (CM), collected from MSCs, did not present tumor-suppressing ability, the activation of PKA converted MSCs into induced tumor-suppressing cells (iTSCs). In a mouse model, the direct and hydrogel-assisted administration of CM inhibited tumor-induced bone destruction, and its effect was additive with cisplatin. CM was enriched with proteins such as calreticulin, which acted as an extracellular tumor suppressor by interacting with CD47. Notably, the level of CALR transcripts was elevated in OS tissues, together with other tumor-suppressing proteins, including histone H4, and PCOLCE. PCOLCE acted as an extracellular tumor-suppressing protein by interacting with amyloid precursor protein, a prognostic OS marker with poor survival. The results supported the possibility of employing a paradoxical strategy of utilizing OS transcriptomes for the treatment of OS.

Blockade of CD47 function attenuates restenosis by promoting smooth muscle cell efferocytosis and inhibiting their migration and proliferation

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 and mouse aortic smooth muscle cells (HASMCs and MASMCs). In exploring the mechanisms, we found that the protease-activated receptor 1 (PAR1)-Gα protein q/11 (Gαq/11)-phospholipase Cβ3 (PLCβ3)-nuclear factor of activated T cells c1 (NFATc1) 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 MASMCs. 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 CDK-interacting protein 1 (p21Cip1). 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.

Cell membrane-coated nanoparticles: a novel multifunctional biomimetic drug delivery system

Recently, nanoparticle-based drug delivery systems have been widely used for the treatment, prevention, and detection of diseases. Improving the targeted delivery ability of nanoparticles has emerged as a critical issue that must be addressed as soon as possible. The bionic cell membrane coating technology has become a novel concept for the design of nanoparticles. The diverse biological roles of cell membrane surface proteins endow nanoparticles with several functions, such as immune escape, long circulation time, and targeted delivery; therefore, these proteins are being extensively studied in the fields of drug delivery, detoxification, and cancer treatment. Furthermore, hybrid cell membrane-coated nanoparticles enhance the beneficial effects of monotypic cell membranes, resulting in multifunctional and efficient delivery carriers. This review focuses on the synthesis, development, and application of the cell membrane coating technology and discusses the function and mechanism of monotypic/hybrid cell membrane-modified nanoparticles in detail. Moreover, it summarizes the applications of cell membranes from different sources and discusses the challenges that may be faced during the clinical application of bionic carriers, including their production, mechanism, and quality control. We hope this review will attract more scholars toward bionic cell membrane carriers and provide certain ideas and directions for solving the existing problems.

Inhibitory effects of circulating natural autoantibodies to CD47-derived peptides on OSCC cells

OBJECTIVES

Natural autoantibodies serve as an important anti-tumorigenic component in the body. This study was thus designed to investigate whether circulating natural IgG autoantibodies against a cluster of differentiation 47 (CD47) could exert inhibitory effects on oral squamous cell carcinoma (OSCC).

SUBJECTS AND METHODS

The expression levels of 13 tumor-targeted genes in three OSCC cell lines were analyzed by qPCR, and CD47 expression in OSCC tissues was also verified with IHC staining. An in-house ELISA was performed to analyze circulating anti-CD47 IgG levels in control subjects, oral benign tumor, and OSCC patients, and to detect anti-CD47 IgG-abundant plasma. Three OSCC cell lines were treated with anti-CD47 IgG-abundant and -deficient plasma, respectively, followed by the analysis of cell proliferation, apoptosis, and invasion/metastasis.

RESULTS

The CD47 gene showed the highest expression among 13 genes detected in three OSCC cell lines; its expression was significantly higher in OSCC tissues than adjacent tissues. Plasma anti-CD47 IgG levels showed the differences between control subjects, oral benign tumor, and OSCC patients. Anti-CD47 IgG-abundant plasma could evidently reduce cell viability via suppressing p-AKT expression and inducing cell apoptosis and inhibit the invasion of all three OSCC cell lines.

CONCLUSIONS

Natural autoantibodies against CD47 may be a potential agent for OSCC immunotherapy.

THE CIS ASSOCIATION OF CD47 WITH INTEGRIN Mac-1 REGULATES MACROPHAGE RESPONSES BY STABILIZING THE EXTENDED INTEGRIN CONFORMATION

CD47 is a ubiquitously expressed cell surface integrin-associated protein. Recently, we have demonstrated that integrin Mac-1 (α_Mβ₂, CD11b/CD18, CR3), the major adhesion receptor on the surface of myeloid cells, can be coprecipitated with CD47. However, the molecular basis for the CD47-Mac-1 interaction and its functional consequences remain unclear. Here, we demonstrated that CD47 regulates macrophage functions directly interacting with Mac-1. In particular, adhesion, spreading, migration, phagocytosis, and fusion of CD47-deficient macrophages were significantly decreased. We validated the functional link between CD47 and Mac-1 by co-immunoprecipitation analysis using various Mac-1-expressing cells. In HEK293 cells expressing individual α_M and β₂ integrin subunits, CD47 was found to bind both subunits. Interestingly, a higher amount of CD47 was recovered with the free β₂ subunit than in the complex with the whole integrin. Furthermore, activating Mac-1-expressing HEK293 cells with PMA, Mn²⁺_, and activating antibody MEM48 increased the amount of CD47 in complex with Mac-1, suggesting CD47 has a greater affinity for the extended integrin conformation. Notably, on the surface of cells lacking CD47, fewer Mac-1 molecules could convert into an extended conformation in response to activation. Additionally, we identified the binding site in CD47 for Mac-1 in its constituent IgV domain. The complementary binding sites for CD47 in Mac-1 were localized in integrin epidermal growth factor-like domains 3 and 4 of the β₂ and calf-1 and calf-2 domains of the α subunits. These results indicate that Mac-1 forms a lateral complex with CD47, which regulates essential macrophage functions by stabilizing the extended integrin conformation.

CD47 and CD68 expression in breast cancer is associated with tumor-infiltrating lymphocytes, blood vessel invasion, detection mode, and prognosis

CD47 expressed on tumor cells binds to signal regulatory protein alpha on macrophages, initiating inhibition of phagocytosis. We investigated the relationships between tumor expression of CD47 and CD68 macrophage content, subsets of tumor-infiltrating lymphocytes (TILs), and vascular invasion in breast cancer. A population-based series of 282 cases (200 screen detected and 82 interval patients) from the Norwegian Breast Cancer Screening Program was examined. Immunohistochemical staining for CD47 and CD68 was evaluated on tissue microarray (TMA) slides. For CD47 evaluation, a staining index was used. CD68 tumor-associated macrophages were counted and dichotomized. TIL subsets (CD45, CD3, CD4, CD8, and FOXP3) were counted and dichotomized using immunohistochemistry on TMA slides. Vascular invasion (both lymphatic and blood vessel) was determined on whole tissue slides. High CD47 tumor cell expression or high counts of CD68 macrophages were significantly associated with elevated levels of all TIL subsets (p < 0.02), CD163 macrophages (p < 0.001), blood vessel invasion (CD31 positive) (p < 0.01), and high tumor cell Ki67 (p < 0.004). High CD47 expression was associated with ER negativity (p < 0.001), HER2 positive status (p = 0.03), and interval-detected tumors (p = 0.03). Combined high expression of CD47-CD68 was associated with a shorter recurrence-free survival (RFS) by multivariate analysis (hazard ratio [HR]: 2.37, p = 0.018), adjusting for tumor diameter, histologic grade, lymph node status, and molecular subtype. Patients with luminal A tumors showed a shorter RFS for CD47-CD68 high cases by multivariate assessment (HR: 5.73, p = 0.004). This study demonstrates an association of concurrent high CD47 tumor cell expression and high CD68 macrophage counts with various TIL subsets, blood vessel invasion (CD31 positive), other aggressive tumor features, and interval-presenting breast cancer. Our findings suggest a link between CD47, tumor immune response, and blood vessel invasion (CD31 positive). Combined high expression of CD47-CD68 was an independent prognostic factor associated with poor prognosis in all cases, as well as in the luminal A category.

Tumor-selective Blockade of CD47 Signaling with CD47 Antibody for Enhanced Anti-tumor Activity in Malignant Meningioma

BACKGROUND

Patients with WHO grade III meningioma have a poor prognosis with a median survival of less than two years and a high risk of recurrence. However, traditional treatment options have failed to improve prognosis. Therefore, development of novel immunotherapy targets is urgently needed. CD47 acting as a "don't eat me" signal to macrophages can trigger tumor immune escape. However, the role of CD47 in malignant meningioma is not well understood.

METHODS

We collected 190 clinical meningioma samples and detected the expression of CD47 and immune infiltration in WHO grade I-III by immunohistochemistry, western blot, qPCR. We also examined the functional effects of anti-CD47 on cell proliferation, migration and invasion, macrophagemediated phagocytosis and tumorigenicity both in vitro and in vivo.

RESULTS

We found that the expression of CD47 was increased in malignant meningioma along with a decreased number of T cells and an increase in CD68+ macrophages. Blocking CD47 with anti-CD47 antibody (B6H12) suppressed tumor cell growth, motility and promoted macrophage-mediated phagocytosis in IOMM-Lee cells in vitro. In vivo experiments showed that anti-CD47 antibody (B6H12 or MIAP301) significantly inhibited the tumor growth and this effect was partly blocked by the depletion of macrophages. Finally, p-ERK and EGFR showed higher expression in malignant meningioma with high expression of CD47, which was verified by western blot.

CONCLUSION

Our results demonstrated that CD47 maybe involved in the meningioma progression and prognosis and offered a novel therapeutic option by targeting CD47 in malignant meningioma.

Current Status of Novel Agents for the Treatment of B Cell Malignancies: What's Coming Next?

Resistance to death is one of the hallmarks of human B cell malignancies and often contributes to the lack of a lasting response to today's commonly used treatments. Drug discovery approaches designed to activate the death machinery have generated a large number of inhibitors of anti-apoptotic proteins from the B-cell lymphoma/leukemia 2 family and the B-cell receptor (BCR) signaling pathway. Orally administered small-molecule inhibitors of Bcl-2 protein and BCR partners (e.g., Bruton's tyrosine kinase and phosphatidylinositol-3 kinase) have already been included (as monotherapies or combination therapies) in the standard of care for selected B cell malignancies. Agonistic monoclonal antibodies and their derivatives (antibody-drug conjugates, antibody-radioisotope conjugates, bispecific T cell engagers, and chimeric antigen receptor-modified T cells) targeting tumor-associated antigens (TAAs, such as CD19, CD20, CD22, and CD38) are indicated for treatment (as monotherapies or combination therapies) of patients with B cell tumors. However, given that some patients are either refractory to current therapies or relapse after treatment, novel therapeutic strategies are needed. Here, we review current strategies for managing B cell malignancies, with a focus on the ongoing clinical development of more effective, selective drugs targeting these molecules, as well as other TAAs and signaling proteins. The observed impact of metabolic reprogramming on B cell pathophysiology highlights the promise of targeting metabolic checkpoints in the treatment of these disorders.

Tumor-Associated Macrophages and Related Myelomonocytic Cells in the Tumor Microenvironment of Multiple Myeloma

Multiple myeloma (MM) is the second-most common hematologic malignancy and remains incurable despite potent plasma cell directed therapeutics. The tumor microenvironment (TME) is a key player in the pathogenesis and progression of MM and is an active focus of research with a view to targeting immune dysregulation. Tumor-associated macrophages (TAM), myeloid derived suppressor cells (MDSC), and dendritic cells (DC) are known to drive progression and treatment resistance in many cancers. They have also been shown to promote MM progression and immune suppression in vitro, and there is growing evidence of their impact on clinical outcomes. The heterogeneity and functional characteristics of myelomonocytic cells in MM are being unraveled through high-dimensional immune profiling techniques. We are also beginning to understand how they may affect and be modulated by current and future MM therapeutics. In this review, we provide an overview of the biology and clinical relevance of TAMs, MDSCs, and DCs in the MM TME. We also highlight key areas to be addressed in future research as well as our perspectives on how the myelomonocytic compartment of the TME may influence therapeutic strategies of the future.

Emerging Biomaterials Imaging Antitumor Immune Response

Immunotherapy is one of the most promising clinical modalities for the treatment of malignant tumors and has shown excellent therapeutic outcomes in clinical settings. However, it continues to face several challenges, including long treatment cycles, high costs, immune-related adverse events, and low response rates. Thus, it is critical to predict the response rate to immunotherapy by using imaging technology in the preoperative and intraoperative. Here, the latest advances in nanosystem-based biomaterials used for predicting responses to immunotherapy via the imaging of immune cells and signaling molecules in the immune microenvironment are comprehensively summarized. Several imaging methods, such as fluorescence imaging, magnetic resonance imaging, positron emission tomography imaging, ultrasound imaging, and photoacoustic imaging, used in immune predictive imaging, are discussed to show the potential of nanosystems for distinguishing immunotherapy responders from nonresponders. Nanosystem-based biomaterials aided by various imaging technologies are expected to enable the effective prediction and diagnosis in cases of tumors, inflammation, and other public diseases.

Identification of MAN1B1 as a Novel Marker for Bladder Cancer and Its Relationship with Immune Cell Infiltration

Bladder cancer (BC) is a common malignant tumor of the genitourinary system, and there are not enough tumor biomarker tests that are specific, trustworthy, and noninvasive for the diagnosis and prognosis. The purpose of this study is to investigate the clinical relevance, prognostic value, and immunological signature of Mannosidase alpha class 1B member 1(MAN1B1) expressions in BC. The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) databases provided the raw information that was used to analyze the expression of MAN1B1 in tumor patients. Then, a statistical study was carried out to assess the correlations of MAN1B1 expression with the clinical characteristics and the prognosis of BC. The correlation between MAN1B1 expression and tumor immune infiltration was explored via single-sample gene set enrichment analysis (ssGSEA). In human cancers, MAN1B1 expressions were shown to be generally higher in tumors than in normal specimens. We confirmed that MAN1B1 expression was distinctly increased in BC specimens compared with nontumor specimens. BC specimens with advanced T stage and M stage showed a higher level of MAN1B1. Survival analysis revealed that the overall survival (OS), disease-specific survival (DSS), and progression-free interval (PFI) of patients with high MAN1B1 expressions were distinctly worse than those with low MAN1B1 expressions. Importantly, multivariate analyses only confirmed that MAN1B1 expression was an independent prognostic factor for OS of the patients with BC. Furthermore, we observed that MAN1B1 expression level was significantly correlated with abundance of multiple immune infiltrates including Th2 cells, macrophages, Th1 cells, neutrophils, T helper cells, and NK CD56 bright cells. In conjunction with all of these findings, elevated MAN1B1 expression is associated with a poor prognosis and a higher number of immune cells in BC. MAN1B1 has the potential to act as a biomarker that can evaluate both the patient's prognosis and the degree of immune infiltration in BC.

Comparing extracellular vesicles and cell membranes as biocompatible coatings for gold nanorods: Implications for targeted theranostics

Extracellular vesicles (EVs) and cell membrane nanoghosts are excellent coatings for nanomaterials, providing enhanced delivery in the target sites and evasion of the immune system. These cell-derived coatings allow the exploration of the delivery properties of the nanoparticles without stimulation of the immune system. Despite the advances reported on the use of EVs and cell-membrane coatings for nanomedicine applications, there are no standards to compare the benefits and main differences between these technologies. Here we investigated macrophage-derived EVs and cell membranes-coated gold nanorods and compared both systems in terms of target delivery in cancer and stromal cells. Our results reveal a higher tendency of EV-coated nanorods to interact with macrophages yet both EV and cell membrane-coated nanorods were internalized in the metastatic breast cancer cells. The main differences between these nanoparticles are related to the presence or absence of CD47 in the coating material, not usually addressed in EVs characterization. Our findings highlight important delivery differences exhibited by EVs- or cell membranes- coated nanorods which understanding may be important to the design and development of theragnostic nanomaterials using these coatings for target delivery.

Understanding Tricky Cellular and Molecular Interactions in Pancreatic Tumor Microenvironment: New Food for Thought

Pancreatic ductal adenocarcinoma (PDAC) represents 90% of all pancreatic cancer cases and shows a high mortality rate among all solid tumors. PDAC is often associated with poor prognosis, due to the late diagnosis that leads to metastasis development, and limited efficacy of available treatments. The tumor microenvironment (TME) represents a reliable source of novel targets for therapy, and even if many of the biological interactions among stromal, immune, and cancer cells that populate the TME have been studied, much more needs to be clarified. The great limitation in the efficacy of current standard chemoterapy is due to both the dense fibrotic inaccessible TME barrier surrounding cancer cells and the immunological evolution from a tumor-suppressor to an immunosuppressive environment. Nevertheless, combinatorial therapies may prove more effective at overcoming resistance mechanisms and achieving tumor cell killing. To achieve this result, a deeper understanding of the pathological mechanisms driving tumor progression and immune escape is required in order to design rationale-based therapeutic strategies. This review aims to summarize the present knowledge about cellular interactions in the TME, with much attention on immunosuppressive functioning and a specific focus on extracellular matrix (ECM) contribution.

Multifunctional Immunoliposomes Enhance the Immunotherapeutic Effects of PD-L1 Antibodies against Melanoma by Reprogramming Immunosuppressive Tumor Microenvironment

The immunosuppressive tumor microenvironment (TME) can significantly limit the immunotherapeutic effects of the PD-L1 antibody (aPDL1) by inhibiting the infiltration of CD8+ cytotoxic T cells (CTLs) into the tumor tissues. However, how to reprogram the immunosuppressive TME and promote the infiltration of CTLs remains a huge challenge for aPDL1 to achieve the maximum benefits. Herein, the authors design a multifunctional immunoliposome that encapsulates the adrenergic receptor blocker carvedilol (CAR) and connects the "don't eat me" signal antibody (aCD47) and aPDL1 in series via a reactive oxygen species (ROS)-sensitive linker on the surface. In ROS-enriched immunosuppressive TME, the multifunctional immunoliposome (CAR@aCD47/aPDL1-SSL) can first release the outer aCD47 to block the "do not eat me" pathway, promote the phagocytosis of tumor cells by phagocytic cells, and activate CTLs. Then, the aPDL1 on the liposome surface is exposed to block the PD-1/PD-L1 signaling pathway, thereby inducing CTLs to kill tumor cells. CAR encapsulated in CAR@aCD47/aPDL1-SSL can block the adrenergic nerves in the tumor tissues and reduce their densities, thereby inhibiting angiogenesis in the tumor tissues and reprogramming the immunosuppressive TME. According to the results, CAR@aCD47/aPDL1-SSL holds an effective way to reprogram the immunosuppressive TME and significantly enhance immunotherapeutic efficiency of aPDL1 against the primary cancer and metastasis.

CD47-SIRPα-targeted therapeutics: status and prospects

CD47 is a "don't eat me" signal to phagocytes that is overexpressed on many tumor cells as a potential mechanism for immune surveillance evasion. CD47 and its interaction with signal-regulating protein alpha (SIRPα) on phagocytes is therefore a promising cancer target. Therapeutic antibodies and fusion proteins that block CD47 or SIRPα have been developed and have shown activity in preclinical models of hematologic and solid tumors. Anemia is a common adverse event associated with anti-CD47 treatment, but mitigation strategies-including use of a low 'priming' dose-have substantially reduced this risk in clinical studies. While efficacy in single-agent clinical studies is lacking, findings from studies of CD47-SIRPα blockade in combination with agents that increase 'eat me' signals or with antitumor antibodies are promising. Magrolimab, an anti-CD47 antibody, is the furthest along in clinical development among agents in this class. Magrolimab combination therapy in phase Ib/II studies has been well tolerated with encouraging response rates in hematologic and solid malignancies. Similar combination therapy studies with other anti-CD47-SIRPα agents are beginning to report. Based on these early clinical successes, many trials have been initiated in hematologic and solid tumors testing combinations of CD47-SIRPα blockade with standard therapies. The results of these studies will help determine the role of this novel approach in clinical practice and are eagerly awaited.

SLC5A3-Dependent Myo-inositol Auxotrophy in Acute Myeloid Leukemia

An enhanced requirement for nutrients is a hallmark property of cancer cells. Here, we optimized an in vivo genetic screening strategy in acute myeloid leukemia (AML), which led to the identification of the myo-inositol transporter SLC5A3 as a dependency in this disease. We demonstrate that SLC5A3 is essential to support a myo-inositol auxotrophy in AML. The commonality among SLC5A3-dependent AML lines is the transcriptional silencing of ISYNA1, which encodes the rate-limiting enzyme for myo-inositol biosynthesis, inositol-3-phosphate synthase 1. We use gain- and loss-of-function experiments to reveal a synthetic lethal genetic interaction between ISYNA1 and SLC5A3 in AML, which function redundantly to sustain intracellular myo-inositol. Transcriptional silencing and DNA hypermethylation of ISYNA1 occur in a recurrent manner in human AML patient samples, in association with IDH1/IDH2 and CEBPA mutations. Our findings reveal myo-inositol as a nutrient dependency in AML caused by the aberrant silencing of a biosynthetic enzyme. SIGNIFICANCE: We show how epigenetic silencing can provoke a nutrient dependency in AML by exploiting a synthetic lethality relationship between biosynthesis and transport of myo-inositol. Blocking the function of this solute carrier may have therapeutic potential in an epigenetically defined subset of AML.This article is highlighted in the In This Issue feature, p. 275.

Protein tyrosine phosphatases in skeletal development and diseases

Skeletal development and homeostasis in mammals are modulated by finely coordinated processes of migration, proliferation, differentiation, and death of skeletogenic cells originating from the mesoderm and neural crest. Numerous molecular mechanisms are involved in these regulatory processes, one of which is protein posttranslational modifications, particularly protein tyrosine phosphorylation (PYP). PYP occurs mainly through the action of protein tyrosine kinases (PTKs), modifying protein enzymatic activity, changing its cellular localization, and aiding in the assembly or disassembly of protein signaling complexes. Under physiological conditions, PYP is balanced by the coordinated action of PTKs and protein tyrosine phosphatases (PTPs). Dysregulation of PYP can cause genetic, metabolic, developmental, and oncogenic skeletal diseases. Although PYP is a reversible biochemical process, in contrast to PTKs, little is known about how this equilibrium is modulated by PTPs in the skeletal system. Whole-genome sequencing has revealed a large and diverse superfamily of PTP genes (over 100 members) in humans, which can be further divided into cysteine (Cys)-, aspartic acid (Asp)-, and histidine (His)-based PTPs. Here, we review current knowledge about the functions and regulatory mechanisms of 28 PTPs involved in skeletal development and diseases; 27 of them belong to class I and II Cys-based PTPs, and the other is an Asp-based PTP. Recent progress in analyzing animal models that harbor various mutations in these PTPs and future research directions are also discussed. Our literature review indicates that PTPs are as crucial as PTKs in supporting skeletal development and homeostasis.

Loss of myeloid cell-specific SIRPα, but not CD47, attenuates inflammation and suppresses atherosclerosis

AIMS

Inhibitors of the anti-phagocytic CD47-SIRPα immune checkpoint are currently in clinical development for a variety of haematological and solid tumours. Application of immune checkpoint inhibitors to the cardiovascular field is limited by the lack of preclinical studies using genetic models of CD47 and SIRPα inhibition. In this study, we comprehensively analysed the effects of global and cell-specific SIRPα and CD47 deletion on atherosclerosis development.

METHODS AND RESULTS

Here, we show that both SIRPα and CD47 expression are increased in human atherosclerotic arteries and primarily co-localize to CD68+ areas in the plaque region. Hypercholesterolaemic mice homozygous for a Sirpa mutant lacking the signalling cytoplasmic region (Sirpamut/mut) and myeloid cell-specific Sirpa-knockout mice are protected from atherosclerosis. Further, global Cd47-/- mice are protected from atherosclerosis but myeloid cell-specific deletion of Cd47 increased atherosclerosis development. Using a combination of techniques, we show that loss of SIRPα signalling in macrophages stimulates efferocytosis, reduces cholesterol accumulation, promotes lipid efflux, and attenuates oxidized LDL-induced inflammation in vitro and induces M2 macrophage phenotype and inhibits necrotic core formation in the arterial wall in vivo. Conversely, loss of myeloid cell CD47 inhibited efferocytosis, impaired cholesterol efflux, augmented cellular inflammation, stimulated M1 polarization, and failed to decrease necrotic core area in atherosclerotic vessels. Finally, comprehensive blood cell analysis demonstrated lower haemoglobin and erythrocyte levels in Cd47-/- mice compared with wild-type and Sirpamut/mut mice.

CONCLUSION

Taken together, these findings identify SIRPα as a potential target in atherosclerosis and suggest the importance of cell-specific CD47 inhibition as a future therapeutic strategy.

Immunotherapy in older patients with hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common types of cancer globally and is currently the third leading cause of cancer-related deaths. Recently, immunotherapy using immune checkpoint inhibitors (ICIs) has been shown with encouraging anticancer activity and safety in clinical trials. To reverse the phenomenon of tumours evading immune response, ICIs can be used to stimulate the natural antitumour potential of cancer cells by blocking the relevant checkpoints to activate T cells. However, the components and functions of the immune system may undergo a series of changes with ageing, known as 'immunosenescence,' potentially affecting the antitumour effect and safety of immunotherapy. In the current phase III clinical trials of ICIs including nivolumab, pembrolizumab and atezolizumab, the proportion of patients with HCC older than 65 years in CheckMate 459, KEYNOTE-240 and IMbrave150 is 51%, 58% and 50%, respectively, which is less than 70%-73% of epidemiological investigation. Therefore, the elderly population recruited in clinical trials may not accurately represent the real-world elderly patients with HCC, which affects the extrapolation of the efficacy and safety profile obtained in clinical trials to the elderly population in the real world. This review provides the latest advances in ICIs immuno-treatment available for HCC and relevant information about their therapeutic effects and safety on elderly patients. We discuss the benefits of ICIs for older HCC patients, and relevant recommendations about conducting further clinical trials are proposed for more complete answers to this clinical issue.

Clinical Response to Anti-CD47 Immunotherapy Is Associated with Rapid Reduction of Exhausted Bystander CD4+ BTLA+ T Cells in Tumor Microenvironment of Mycosis Fungoides

Simple Summary

The identification of the events that accompany cancer progression is essential for developing new therapies. We have used mycosis fungoides, the most common type of cutaneous lymphoma, as a model for our study. We have shown that cancer progression is accompanied by the expansion of exhausted immune cells around malignant cells. Those exhausted cells prevent immune activation, blocking cancer clearance by the immune system. Furthermore, we have demonstrated that novel anti-CD47 immunotherapy with mycosis fungoides leads to the reduction of exhausted T cells accompanied by the expansion of NK and CD8⁺ T cells. These therapeutic benefits of CD47 blockade were further facilitated by interferon-α, which stimulates cytotoxic cells. Thus, we showed that CD47 might serve as an effective therapeutic target in treating mycosis fungoides.

Abstract

Cancer progression in mycosis fungoides, the most common form of cutaneous T-cell lymphoma, occurs in a predictable, sequential pattern that starts from patches and that evolves to plaques and later to tumors. Therefore, unlocking the relationship between the microarchitecture of mycosis fungoides and the clinical counterparts of that microstructure represents important steps for the design of targeted therapies. Using multispectral fluorescent imaging, we show that the progression of mycosis fungoides from plaque to tumor parallels the cutaneous expansion of the malignant CD4⁺ T cells that express TOX. The density of exhausted BTLA⁺ CD4⁺ T cells around malignant CD4⁺TOX⁺ cells was higher in tumors than it was in plaques, suggesting that undesired safeguards are in place within the tumor microenvironment that prevent immune activation and subsequent cancer eradication. Overriding the CD47 checkpoint with an intralesional SIRPαFc fusion decoy receptor induced the resolution of mycosis fungoides in patients that paralleled an amplified expansion of NK and CD8⁺ T cells in addition to a reduction of the exhausted BTLA⁺ CD4⁺ T cells that were engaged in promiscuous intercellular interactions. These therapeutic benefits of the CD47 blockade were further unleashed by adjuvant interferon-α, which stimulates cytotoxic cells, underscoring the importance of an inflamed microenvironment in facilitating the response to immunotherapy. Collectively, these findings support CD47 as a therapeutic target in treating mycosis fungoides and demonstrate a synergistic role of interferon-α in exploiting these clinical benefits.

From Immune Dysregulations to Therapeutic Perspectives in Myelodysplastic Syndromes: A Review

The pathophysiology of myelodysplastic syndromes (MDSs) is complex and often includes immune dysregulation of both the innate and adaptive immune systems. Whereas clonal selection mainly involves smoldering inflammation, a cellular immunity dysfunction leads to increased apoptosis and blast proliferation. Addressing immune dysregulations in MDS is a recent concept that has allowed the identification of new therapeutic targets. Several approaches targeting the different actors of the immune system have therefore been developed. However, the results are very heterogeneous, indicating the need to improve our understanding of the disease and interactions between chronic inflammation, adaptive dysfunction, and somatic mutations. This review highlights current knowledge of the role of immune dysregulation in MDS pathophysiology and the field of new drugs.

Targeting Ovarian Carcinoma with TSP-1:CD47 Antagonist TAX2 Activates Anti-Tumor Immunity

TAX2 peptide is a cyclic peptide that acts as an orthosteric antagonist for thrombospondin-1 (TSP-1) interaction with CD47. TAX2 was first described for its anti-angiogenic activities and showed anti-cancer efficacy in numerous preclinical models. Here, we aimed at providing an extensive molecular characterization of TAX2 mode of action, while evaluating its potential in ovarian cancer therapy. Multidisciplinary approaches were used to qualify a TAX2 drug candidate in terms of stability, solubility and potency. Then, efficacy studies, together with benchmark experiments, were performed in relevant mouse models of ovarian carcinoma. TAX2 peptide appears to be stable and soluble in clinically relevant solvents, while displaying a favorable safety profile. Moreover, clinical data mining allowed for the identification of TSP-1 as a relevant pharmacological target in ovarian cancer. In mice, TAX2 therapy inhibits ovarian tumor growth and metastatic dissemination, while activating anti-cancer adaptive immunity. Interestingly, TAX2 also synergizes when administered in combination with anti-PD-1 immune checkpoint inhibitiors. Altogether, our data expose TAX2 as an optimized candidate with advanced preclinical characterization. Using relevant syngeneic ovarian carcinoma models, we highlighted TAX2's ability to convert poorly immunogenic tumors into ones displaying effective anti-tumor T-cell immunity.

Decreased Thrombospondin-1 and Bone Morphogenetic Protein-4 Serum Levels as Potential Indices of Advanced Stage Lung Cancer

Introduction: Lung cancer belongs to the most common carcinoma worldwide and is the leading cause of cancer-related death. Bone morphogenetic protein-4 (BMP-4) is extracellular signaling molecule involved in many important processes, including cell proliferation and mobility, apoptosis and angiogenesis. Thrombospondin-1 (TSP-1) belongs to the extracellular matrix proteins. It participates in the cell-to-cell and cell-to-matrix interactions and thus plays important role in tumor microenvironment for cancer development and metastasis formation. Aim: To investigate serum levels of TSP-1 and BMP-4 together with BMP-4 polymorphism in lung cancer patients. Material and Methods: A total of 111 patients (76 men) with newly diagnosed lung cancer, including 102 patients with non-small cell lung cancer and 9 patients with small-cell lung cancer. Advanced stage of lung cancer was diagnosed in 99 (89%) of patients: stage IV—in 48, stage IIIB—in 33, stage IIIA—in 18 patients; there were six patients with stage II and six patients with stage I. The control group consisted of 61 healthy persons. In all the subjects, serum levels of BMP-4 and TSP-1 were measured by ELISA. With a Real-Time PCR system genotyping of BMP-4 was performed. Results: BMP-4 and TSP-1 serum levels were significantly lower in the patients with lung cancer than in the controls (TSP-1:10,109.2 ± 9581 ng/mL vs. 11,415.09 ± 9781 ng/mL, p < 0.05; BMP-4: 138.35 ± 62.59 pg/mL vs. 226.68 ± 135.86 pg/mL p < 0.001). In lung cancer patients TSP-1 levels were lower in advanced stages (9282.07 ± 4900.78 ng/mL in the stages III-IV vs. 16,933.60 ± 6299.02 ng/mL in the stages I-II, p < 0.05) and in the patients with than without lymph nodes involvement (10,000.13 ± 9021.41 ng/mL vs. 18,497.75 ± 12,548.25 ng/mL, p = 0.01). There was no correlation between TSP-1 and BMP-4 serum levels. BMP-4 gene polymorphism did not influence the results of the study. Conclusion: Decreased levels of TSP-1 and BMP-4 may serve as potential indices of lung cancer, with additional importance of low TSP-1 level as a marker of advanced stage of the disease.

Computational Approaches for Cancer-Fighting: From Gene Expression to Functional Foods

It is today widely accepted that a healthy diet is very useful to prevent the risk for cancer or its deleterious effects. Nutrigenomics studies are therefore taking place with the aim to test the effects of nutrients at molecular level and contribute to the search for anti-cancer treatments. These efforts are expanding the precious source of information necessary for the selection of natural compounds useful for the design of novel drugs or functional foods. Here we present a computational study to select new candidate compounds that could play a role in cancer prevention and care. Starting from a dataset of genes that are co-expressed in programmed cell death experiments, we investigated on nutrigenomics treatments inducing apoptosis, and searched for compounds that determine the same expression pattern. Subsequently, we selected cancer types where the genes showed an opposite expression pattern and we confirmed that the apoptotic/nutrigenomics expression trend had a significant positive survival in cancer-affected patients. Furthermore, we considered the functional interactors of the genes as defined by public protein-protein interaction data, and inferred on their involvement in cancers and/or in programmed cell death. We identified 7 genes and, from available nutrigenomics experiments, 6 compounds effective on their expression. These 6 compounds were exploited to identify, by ligand-based virtual screening, additional molecules with similar structure. We checked for ADME criteria and selected 23 natural compounds representing suitable candidates for further testing their efficacy in apoptosis induction. Due to their presence in natural resources, novel drugs and/or the design of functional foods are conceivable from the presented results.

CD47 blockade enhances therapeutic efficacy of cisplatin against lung carcinoma in a murine model

Cisplatin (CDDP) is the first generation of platinum-based drug and is widely used to treat many cancers due to its potency. The present study aims to explore the effects of CDDP on lung carcinoma and its relationship with macrophage phagocytosis. In in vitro study, murine and human lung cancer cell lines were applied and treated with CDDP, CD47 antibody (aCD47), or CDDP plus aCD47. In in vivo study, a tumor xenograft animal model was treated with CDDP, aCD47, or CDDP plus aCD47. Real-time PCR was applied to determine the mRNA expressions. Enzyme-linked immunosorbent assay (ELISA), Western blotting, and Immunofluorescent staining were applied to determine the protein expressions. Flow cytometry was applied to analyze cell apoptosis, phagocytosis, and specific cell populations. CDDP enhanced the expressions of CD47 in lung cancer cells. Interestingly, the blockage of CD47 enhanced the macrophages' phagocytic activity on the CDDP-treated tumor cells. The treatment of CDDP and aCD47 exhibited anti-tumor effects and prolonged the LLC tumor-bearing mice survival time. Mechanistic studies revealed that the treatment of CDDP and aCD47 regulated the phagocytic activity of macrophage, percentage of CD8+ T cells, and cytokines (tumor growth factor (TGF)-β, interleukin (IL)12p70, and interferon (IFN)-γ) in the tumor-bearing model. CD47 blockade enhanced therapeutic efficacy of cisplatin against lung carcinoma in vivo and in vitro.

Myelodysplastic syndrome and immunotherapy novel to next in-line treatments

Patients with Myelodysplastic syndromes (MDS) have few therapy options for sustainable responses in the frontline setting, and even less after hypomethylating agent (HMA) failure in relapsed and refractory setting. The only potential cure is an allogeneic hematopoietic stem cell transplant which is an unrealistic option for the majority of MDS patients. Immunotherapy with checkpoint inhibition, CAR-T cells, and vaccine therapy few have shown promise in a variety cancer and have now been tested in patients with MDS. Most trials have focused on AML patients and included small numbers of MDS patients. Until now, a dedicated review of immunotherapy outcomes in MDS patients has been lacking. Thus, herein we review outcomes of MDS patients after immunotherapies on a variety of clinical trials reported to date.

Clinicopathological and Prognostic Significance of CD47 Expression in Lung Neuroendocrine Tumors

Background

Lung neuroendocrine tumors account for approximately 15% of all lung cancer cases. LNET are subdivided into typical carcinoid (TC), atypical carcinoid (AC), large cell neuroendocrine carcinoma (LCNEC), and small-cell lung cancer (SCLC). The Ki-67 index has been used for decades to evaluate mitotic counts however, the role of Ki-67 as a biomarker for assessing prognosis and guiding therapy in metastatic LNET still lacks feasible clinical validation. Recent clinical trials have indicated that inhibition of CD47 with anti-CD47 antibodies exerts a promising antitumor effect against several human malignancies, including NSCLC, melanoma, and hematologic malignancies. However, the clinical relevance of CD47 expression in LNET has remained unclear.

Methods

We performed a retrospective study in which we analyzed tumor biopsies from 51 patients with a confirmed diagnosis of LNET that received treatment at our hospital. Then, we analyzed if there was any correlation between CD47 expression with any clinical or pathological characteristic. We also analyzed the prognostic significance of CD47, assessed as progression-free survival and overall survival.

Results

A total of 51 patients with LNET were enrolled in our study. The mean age at diagnosis was 57.6 (±11.6) years; 30 patients were women (59%). 27.5% of patients were positive for CD47 expression, and 72.5% of patients showed a CD47 expression of less than 1% and were considered as negatives. In patients with high-grade tumors (this time defined as Ki-67 > 40%), the positive expression of CD47 was strongly associated with an increased PFS. Albeit, these differences did not reach statistical significance when analyzing OS.

Conclusion

Contrary to what happens in a wide range of hematologic and solid tumors, a higher expression of CD47 in patients with LNET is associated with a better progression-free survival, especially in patients with a Ki-67 ≥ 40%. This "paradox" remains to be confirmed and explained by larger studies.

Characteristics of Natural Killer Cell Interaction with Trophoblast Cells During Pregnancy

BACKGROUND

Maternal natural killer cells (NK cells) are a prevailing leukocyte population in the uteroplacental bed. Current descriptions of the effect of cytokines from the placental microenvironment on the expression of receptors by trophoblast and NK cells are inadequate and contradictory. There is insufficient information about the ability of NK cells to migrate through trophoblast cells.

OBJECTIVE

To assess the impact of conditioned media obtained during culturing of placentas from the first and the third trimesters of healthy pregnancies on the phenotype of trophoblast and NK cells and impact on adhesion and transmigration of NK cells through trophoblast cell layer.

RESULTS

We established that conditioned media obtained from both first and third trimester placentas increased the intensity of CD106, CD49e, CD49a, CD31, CD51/61, and integrin β6 expression by trophoblast cells. Conditioned media obtained from first trimester placentas increased the intensity of CD11a, CD29, CD49d, CD58, CD29 expression by NK cells. The presence of conditioned media from third trimester placentas resulted in more intense CD29, CD49d, CD11a, CD29, CD49d, and CD58 expression by NK cells. Migration of NK cells through trophoblast cells in the presence of conditioned media from first trimester placentas was increased compared with the migration level in the presence of conditioned media from third trimester placentas. This may be associated with increased expression of CD18 by NK cells.

CONCLUSION

First trimester placental secretory products increase adhesion receptor expression by both trophoblast and NK cells. Under these conditions, trophoblast is capable of ensuring NK cell adhesion and transmigration.