The CD47-SIRPα Immune Checkpoint

Platelet membrane-cloaked biomimetic nanoparticles for targeted acute lung injury therapy

Acute lung injury (ALI) is a medical condition characterized by significant morbidity and elevated mortality rates; however, to date, there are no clinically approved pharmacological interventions that are both safe and effective for its treatment. In the pathophysiology of ALI, a robust inflammatory response is a critical factor. Dexamethasone (Dex), a potent glucocorticoid, is commonly employed in clinical settings to manage inflammatory conditions. However, the frequent or high-dose administration of corticosteroids can result in significant adverse effects and long-term complications. In this study, we have developed a biomimetic anti-inflammatory nanosystem, designated PM-LPs@Dex, aimed at treating ALI. This system leverages the inherent affinity of platelets for sites of inflammation, alongside the advantageous drug encapsulation properties of liposomes (LPs). By harnessing the suitable physicochemical characteristics of LPs and the distinctive biological functions of platelet membranes (PM), PM-LPs@Dex is capable of stable and sustained drug release in vitro. Experimental results regarding cellular uptake and biodistribution reveal that PM-LPs@Dex is preferentially internalized by inflammatory cells and exhibits enhanced accumulation in inflamed lung tissue compared to LPs@Dex. Pharmacokinetic studies displayed that PM-LPs@Dex showed prolonged circulation time in blood. Additionally, pharmacodynamic assessments demonstrate that PM-LPs@Dex significantly mitigates the severity of ALI, as evidenced by reductions in pulmonary edema, tissue pathology, bronchoalveolar lavage cell counts, protein concentration, and levels of inflammatory cytokines. Notably, PM-LPs@Dex also exhibits favorable biocompatibility. This research is anticipated to contribute novel strategies for the safe and effective targeted management of inflammatory diseases.

Dual blockade of GSTK1 and CD47 improves macrophage-mediated phagocytosis on cancer cells

CD47 is a crucial anti-phagocytic signal in regulating macrophage responses and its manipulation offers the therapeutic potential in cancer treatment. However, in many cases, blockade of CD47 by itself is insufficient to activate macrophage effectively, indicating other unidentified phagocytosis-regulating factors to resist the macrophage activity. In this study, a genome-wide human CRISPR-Cas9 library was developed for comprehensive screening of phagocytosis-regulating factors in the context of CD47 blockade. The screening results identified GSTK1 as a potential anti-phagocytic signal counteracting the efficacy of CD47-based phagocytosis. The disruption of GSTK1 significantly increased the phagocytosis rate of cancer cells by macrophages in combination with anti-CD47 antibody. Further mechanism investigation unveiled that GSTK1 blockade increased the membrane exposure of calreticulin in different cancer cells, which might be the primary mechanism driving enhanced macrophage-mediated phagocytosis. To this end, siGSTK1-loaded nanoparticles (siGSTK1-LNPs) were designed to suppress the GSTK1 expression efficiently. The comparable phagocytosis efficacy was also observed when combining siGSTK1-LNPs with anti-CD47 antibody. Above all, GSTK1 blockade was identified as a promising and feasible stimulus for enhancing the effectiveness of anti-CD47 antibody, introducing a novel and effective combination approach in cancer immunotherapy.

Multispecific Antibodies Targeting PD-1/PD-L1 in Cancer

The development of immune checkpoint inhibitors has revolutionized the treatment of patients with cancer. Targeting the programmed cell death protein 1 (PD-1)/programmed cell death 1 ligand 1(PD-L1) interaction using monoclonal antibodies has emerged as a prominent focus in tumor therapy with rapid advancements. However, the efficacy of anti-PD-1/PD-L1 treatment is hindered by primary or acquired resistance, limiting the effectiveness of single-drug approaches. Moreover, combining PD-1/PD-L1 with other immune drugs, targeted therapies, or chemotherapy significantly enhances response rates while exacerbating adverse reactions. Multispecific antibodies, capable of binding to different epitopes, offer improved antitumor efficacy while reducing drug-related side effects, serving as a promising therapeutic approach in cancer treatment. Several bispecific antibodies (bsAbs) targeting PD-1/PD-L1 have received regulatory approval, and many more are currently in clinical development. Additionally, tri-specific antibodies (TsAbs) and tetra-specific antibodies (TetraMabs) are under development. This review comprehensively explores the fundamental structure, preclinical principles, clinical trial progress, and challenges associated with bsAbs targeting PD-1/PD-L1.

Neutrophils in cancer: At the crucial crossroads of anti-tumor and pro-tumor

Neutrophils are important components of the immune system and play a key role in defending against pathogenic infections and responding to inflammatory cues, including cancer. Their dysregulation indicates potential disease risk factors. However, their functional importance in disease progression has often been underestimated due to their short half-life, especially as there is limited information on the role of intratumoral neutrophils. Recent studies on their prominent role in cancer have led to a paradigm shift in our understanding of the functional diversity of neutrophils. These studies highlight that neutrophils have emerged as key components of the tumor microenvironment, where they can play a dual role in promoting and suppressing cancer. Moreover, several approaches to therapeutically target neutrophils have emerged, and clinical trials are investigating their efficacy. In this review, we discussed the involvement of neutrophils in cancer initiation and progression. We summarized recent advances in therapeutic strategies targeting neutrophils and, most importantly, suggested future research directions that could facilitate the manipulation of neutrophils for therapeutic purposes in cancer patients.

Protocol for assessing antibody-dependent cellular phagocytosis by primary murine and human macrophages

Macrophages play a crucial role in mediating antibody-dependent cellular phagocytosis (ADCP), a process that enhances the effectiveness of several cancer immunotherapies. In this protocol, we outline detailed steps for isolating, differentiating, and polarizing macrophages from both mouse and human sources. Additionally, we describe an optimized technique to assess ADCP using in vitro co-culture studies followed by flow cytometry analysis. This protocol offers a reliable approach to evaluate the efficiency of macrophage-mediated phagocytosis of cancer cells during treatment with antibody-based therapies. For complete details on the use and execution of this protocol, please refer to Osorio et al.1.

Innate immune checkpoint SIRPα/CD47 blockade ameliorates silica-induced pulmonary fibrosis by modulating macrophage immunity

Silicosis is a fibrotic disease caused by prolonged inhalation of silica particles. Signal regulatory protein alpha (SIRPα) and its ligand CD47, key innate immune checkpoints mediating inhibition of phagocytosis, have been reported to regulate organ fibrosis. However, the role of SIRPα/CD47 in silicosis remains unexplored. In this study, a silicosis mouse model was constructed and revealed a significant upregulation of SIRPα and CD47 expression in lung tissue with disease progression. In addition, the expression patterns of SIRPα and CD47 in various silicosis effector cells exhibit distinct cell specificity. Using RRx-001 to block SIRPα/CD47 signaling in mice, we observed a marked reduction in lung injury, decreased collagen deposition, and improved pulmonary function. Mechanistically, blocking SIRPα/CD47 affected T cell activation, macrophage polarization and the expression of pro-inflammatory and pro-fibrotic factors. In vitro, we found that inhibiting SIRPα/CD47 countered the silica-induced suppression of macrophage phagocytosis and induced macrophage polarization towards the M1 phenotype. Additionally, levels of soluble SIRPα and CD47 in the peripheral blood of silicosis patients were significantly higher than those in healthy controls. In summary, this study demonstrates that SIRPα/CD47-mediated immunomodulatory signaling is the driving factor for the progression of silicosis, and this pathway might serve as a therapeutic target for silicosis treatment.

Cell membrane nanoparticles in cancer therapy: From basic structure to surface functionalization

Cell membrane nanoparticles (CNPs) have recently garnered significant attention as effective drug-delivery vehicles. Beyond their simple function of encapsulating cargo within a lipid bilayer structure, the cell membrane is a complex entity derived from biological materials, presenting a variety of surface proteins and glycans. Notable features that enhance their effectiveness as delivery vehicles include the inhibition of protein corona formation in the plasma and the suppression of macrophage phagocytosis, both of which contribute to prolonged blood circulation. Furthermore, CNPs exhibit homotypic targeting effects toward their cells of origin, resulting in reduced side effects, and because they are not xenobiotics, the likelihood of nonspecific immune activation is also minimized. This review focuses on various applications of CNPs in cancer therapeutic studies, examining their structural evolution and surface engineering developments. We introduce studies that leverage the inherent functionality of cell membranes and recent research in functional CNPs synthesized through genetic or chemical engineering methods. Through this review, we aim to trace the progression of CNP research, explore potential directions for their use in biomedical applications, and assess the prospects for clinical trials.

A combined "eat me/don't eat me" strategy based on exosome for acute liver injury treatment

Drug-induced liver injury (DILI) involves multifaceted pathogenesis, necessitating effective therapeutic strategies. Wnt2, secreted by liver sinusoidal endothelial cell (LSEC), activates the Wnt/β-catenin signaling pathway to promote hepatocyte proliferation after injury. To address the dual challenges of targeted delivery and phagocytosis evasion, we develop a combined "eat me/don't eat me" strategy. RLTRKRGLK (RLTR) peptide-functionalized exosomes are engineered by inserting DMPE-PEG2000-CRLTRKRGLK into the lipid membrane of exosome derived from bEnd.3 cell. Surface-displayed RLTR mediates exosomal enrichment in LSEC, while CD47 engineering reduces macrophage clearance via "don't eat me" signaling. Then, lentiviral transfection enables stable encapsulation of functional Wnt2 mRNA into ExoCD47 (designated Wnt2@ExoCD47). In both acetaminophen (APAP) and dimethylnitrosamine (DMN)-induced murine liver injury models, RLTR-Wnt2@ExoCD47 demonstrates LSEC-specific targeting and significant hepatoprotection. This engineered exosome platform provides a therapeutic strategy for DILI.

Biological mechanisms and immunotherapy of brain metastases in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is a leading cause of cancer-related mortality worldwide, with Brain Metastases serving as a significant adverse prognostic factor. The blood-brain barrier poses a substantial challenge in the treatment of brain metastases, as it restricts the penetration of many anticancer agents. Novel immunotherapy, such as immune checkpoint inhibitors (ICIs) have emerged as promising treatment for NSCLC and its associated brain metastases. This review summarizes the biological mechanism underlying NSCLC brain metastases and provides an overview of the current landscape of immunotherapy, exploring the mechanism of action and clinical applications of these advanced treatments.

MnO2-based nanoparticles remodeling tumor micro-environment to augment sonodynamic immunotherapy against breast cancer

The tumor microenvironment (TME) is characterized by a complex array of factors, including aerobic conditions, high glutathione (GSH) levels, acidic pH, and elevated hydrogen peroxide (H2O2) content, all of which promote cancer progression and contribute to poor prognosis. Fortunately, these challenges can be addressed using MnO2-based nanomaterials. In this study, we have designed and synthesized a Curcumin/MnO2@PLGA@4T1 cell membrane (CMP@4T1m) system aimed at remodelling the TME and enhancing sonodynamic immunotherapy for breast cancer. Through the homologous targeting ability of 4T1m, CMP@4T1m efficiently accumulates at the tumor site. Upon ultrasound irradiation, curcumin (Cur) acts as a sonosensitizer, generating cytotoxic reactive oxygen species (ROS) that induce immunogenic cell death (ICD), activate T-cell responses, and repolarize protumoral M2-like macrophages to antitumoral M1-like macrophages. In the TME, which is mildly acidic and enriched with GSH and H2O2, MnO2 not only oxidizes GSH to glutathione disulfide (GSSG) but also reacts with H2O2 and H+ to produce oxygen, alleviating hypoxia and significantly enhancing the sonodynamic immunotherapy effect. Additionally, Mn2+ generated during this process converts H2O2 into cytotoxic hydroxyl radicals (˙OH). This study thus lays the foundation for advancing cancer nanomedicine, offering a novel approach that integrates TME remodelling with sonodynamic immunotherapy.

DDX54 downregulation enhances anti-PD1 therapy in immune-desert lung tumors with high tumor mutational burden

High tumor mutational burden (TMB-H) is a predictive biomarker for the responsiveness of cancer to immune checkpoint inhibitor (ICI) therapy that indicates whether immune cells can sufficiently recognize cancer cells as nonself. However, about 30% of all cancers from The Cancer Genome Atlas (TCGA) are classified as immune-desert tumors lacking T cell infiltration despite TMB-H. Since the underlying mechanism of these immune-desert tumors has yet to be unraveled, there is a pressing need to transform such immune-desert tumors into immune-inflamed tumors and thereby enhance their responsiveness to anti-PD1 therapy. Here, we present a systems framework for identifying immuno-oncotargets, based on analysis of gene regulatory networks, and validating the effect of these targets in transforming immune-desert into immune-inflamed tumors. In particular, we identify DEAD-box helicases 54 (DDX54) as a master regulator of immune escape in immune-desert lung cancer with TMB-H and show that knockdown of DDX54 can increase immune cell infiltration and lead to improved sensitivity to anti-PD1 therapy.

Enhancing antitumor immunity: the role of immune checkpoint inhibitors, anti-angiogenic therapy, and macrophage reprogramming

Cancer treatment has long been hindered by the complexity of the tumor microenvironment (TME) and the mechanisms that tumors employ to evade immune detection. Recently, the combination of immune checkpoint inhibitors (ICIs) and anti-angiogenic therapies has emerged as a promising approach to improve cancer treatment outcomes. This review delves into the role of immunostimulatory molecules and ICIs in enhancing anti-tumor immunity, while also discussing the therapeutic potential of anti-angiogenic strategies in cancer. In particular, we highlight the critical role of endoplasmic reticulum (ER) stress in angiogenesis. Moreover, we explore the potential of macrophage reprogramming to bolster anti-tumor immunity, with a focus on restoring macrophage phagocytic function, modulating hypoxic tumor environments, and targeting cytokines and chemokines that shape immune responses. By examining the underlying mechanisms of combining ICIs with anti-angiogenic therapies, we also review recent clinical trials and discuss the potential of biomarkers to guide and predict treatment efficacy.

CD47-amyloid-β-CD74 signaling triggers adaptive immunosuppression in sepsis

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. However, how this dysregulation occurs remains to be elucidated. In this study, we use single-cell RNA sequencing (scRNA-seq) and conventional RNA-seq to analyze the immune landscape of sepsis and observe that adaptive immunity is acutely and strongly suppressed. This systemic immunosuppression occurs not only in the peripheral blood but also in all other immune compartments, including the spleen, lymph nodes, and bone marrow. Clinical data show that these adaptive immunity-related genes may have the potential to be used to distinguish patients with sepsis from those with common infections. CD47 is found to play a pivotal role in this immunosuppression by inducing the production of amyloid-β (Aβ), which interacts with CD74 on B cells, leading to B-cell suppression and subsequent adaptive immunosuppression. Blocking CD47-Aβ signaling significantly reduces organ injury and improves the survival rate of septic mice by restoring phagocytic cell functions and alleviating B-cell suppression and adaptive immunosuppression.

Elevated CD47 Expression Impairs Elimination of Photoaged Fibroblasts by Macrophages and Serves as a Potential Biomarker for Photoaging

BACKGROUND

CD47 could negatively regulate macrophage-mediated phagocytosis and contribute to senescent cells accumulation in aging. However, it remains unknown whether CD47 is overexpressed in photoaged skin and involved in photoaging pathogenesis.

AIMS

To investigate the expression, clinical significance, and mechanism of CD47 in photoaging.

METHODS

Sun-exposed (n = 10) and sun-protected (n = 10) skin samples were collected from elderly subjects and stained for CD47, and its association with collagen and elastin content and p16 expression was subsequently analyzed. A cellular photoaging model was then established to examine CD47 expression in photoaged fibroblasts. Furthermore, the influence of photoaged fibroblasts on macrophage-mediated phagocytosis and elimination was assessed by constructing a co-culture system. SiRNA was applied to block the CD47/SIRPα axis to determine its role in this process. Finally, the activation of the CD47/SIRPα axis was evaluated in skin samples.

RESULTS

We showed the increased dermal CD47 expression in sun-exposed aged skin, which was closely correlated with the reduced collagen content and enhanced elastin accumulation and dermal p16 expression. Next, elevated CD47 was detected in both sun-exposed aged skin-derived fibroblasts and photoaged ones. We discovered that photoaged fibroblasts impaired the phagocytotic function of co-cultured macrophages via CD47/SIRPα axis, and blocking the CD47/SIRPα axis could improve their elimination. Moreover, the CD47/SIRPα axis was found to be activated in the sun-exposed aged skin.

CONCLUSIONS

The present study demonstrated for the first time that CD47 was highly expressed and involved in mediating photoaged fibroblasts accumulation, providing important evidence for CD47 as a potential biomarker and therapeutic target for photoaging.

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.

Engineering innate immune cells for cancer immunotherapy

Innate immune cells, including natural killer cells, macrophages and γδ T cells, are gaining prominence as promising candidates for cancer immunotherapy. Unlike conventional T cells, these cells possess attributes such as inherent antitumor activity, rapid immune responses, favorable safety profiles and the ability to target diverse malignancies without requiring prior antigen sensitization. In this Review, we examine the engineering strategies used to enhance their anticancer potential. We discuss challenges associated with each cell type and summarize insights from preclinical and clinical work. We propose strategies to address existing barriers, providing a perspective on the advancement of innate immune engineering as a powerful modality in anticancer treatment.

Microglia efferocytosis: an emerging mechanism for the resolution of neuroinflammation in Alzheimer's disease

Alzheimer's disease (AD) is a complex neurodegenerative disorder characterized by significant neuroinflammatory responses. Microglia, the immune cells of the central nervous system, play a crucial role in the pathophysiology of AD. Recent studies have indicated that microglial efferocytosis is an important mechanism for clearing apoptotic cells and cellular debris, facilitating the resolution of neuroinflammation. This review summarizes the biological characteristics of microglia and the mechanisms underlying microglial efferocytosis, including the factors and signaling pathways that regulate efferocytosis, the interactions between microglia and other cells that influence this process, and the role of neuroinflammation in AD. Furthermore, we explore the role of microglial efferocytosis in AD from three perspectives: its impact on the clearance of amyloid plaques, its regulation of neuroinflammation, and its effects on neuroprotection. Finally, we summarize the current research status on enhancing microglial efferocytosis to alleviate neuroinflammation and improve AD, as well as the future challenges of this approach as a therapeutic strategy for AD.

Super-resolution microscopy unveils the nanoscale organization and self-limiting clustering of CD47 in human erythrocytes

The transmembrane protein CD47, an innate immune checkpoint protein, plays a pivotal role in preventing healthy erythrocytes from immune clearance. Our study utilized stochastic optical reconstruction microscopy (STORM) and single-molecule analysis to investigate the distribution of CD47 on the human erythrocyte membrane. Contrary to previous findings in mouse erythrocytes, we discovered that CD47 exists in randomly distributed monomers rather than in clusters across the human erythrocyte membrane. Using secondary antibody-induced crosslinking, we found that CD47 aggregates into stable clusters within minutes. By comparing these STORM results with those of the fully mobile protein CD59 and the cytoskeleton-bound membrane protein glycophorin C under similar conditions, as well as devising two-color STORM co-labeling and co-clustering experiments, we further quantitatively revealed an intermediate, self-limiting clustering behavior of CD47, elucidating its fractional (∼14%) attachment to the cytoskeleton. Moreover, we report reductions in both the amount of CD47 and its clustering capability in aged erythrocytes, providing new insight into erythrocyte senescence. Together, the combination of STORM and secondary antibody-based crosslinking unveils the unique self-limiting clustering behavior of CD47 due to its fractional cytoskeleton attachment.

Characterizing macrophage diversity in colorectal malignancies through single-cell genomics

Colorectal cancer (CRC) is one of the most common malignant tumors of the digestive tract, with increasing incidence and mortality rates, posing a significant burden on human health. Its progression relies on various mechanisms, among which the tumor microenvironment and tumor-associated macrophages (TAMs) have garnered increasing attention. Macrophage infiltration in various solid tumors is associated with poor prognosis and is linked to chemotherapy resistance in many cancers. These significant biological behaviors depend on the heterogeneity of macrophages. Tumor-promoting TAMs comprise subpopulations characterized by distinct markers and unique transcriptional profiles, rendering them potential targets for anticancer therapies through either depletion or reprogramming from a pro-tumoral to an anti-tumoral state. Single-cell RNA sequencing technology has significantly enhanced our research resolution, breaking the traditional simplistic definitions of macrophage subtypes and deepening our understanding of the diversity within TAMs. However, a unified elucidation of the nomenclature and molecular characteristics associated with this diversity remains lacking. In this review, we assess the application of conventional macrophage polarization subtypes in colorectal malignancies and explore several unique subtypes defined from a single-cell omics perspective in recent years, categorizing them based on their potential functions.

SIRPα modulates microglial efferocytosis and neuroinflammation following experimental subarachnoid hemorrhage via the SHP1/STAT6 axis

Subarachnoid hemorrhage induces extensive neuronal cell death, leading to the release of damage-associated molecular patterns (DAMPs). These DAMPs, along with hemoglobin and cell corpses, trigger localized inflammation. Signal regulatory protein alpha (SIRPα) plays a crucial role in efferocytosis by acting as a "don't eat-me" signal, modulating inflammation and tissue homeostasis. However, the precise function and regulatory mechanisms of SIRPα in efferocytosis remain unclear. Proteomic analysis of cerebrospinal fluid (CSF) reveals that SIRPα levels are significantly elevated in the CSF of SAH patients and correlate with clinical outcomes. In vivo and in vitro studies show that microglial knockdown of SIRPα promotes efferocytosis and attenuates neuroinflammation following SAH. SIRPα inhibits efferocytosis by recruiting and phosphorylating SHP1 and SHP2 through phosphorylation of four tyrosine residues in its cytoplasmic domain, with SHP1 playing a particularly critical role. Mutation of these tyrosine residues to non-phosphorylatable alanine residues enhances efferocytosis and reduces neuroinflammation in vitro. RNA-seq analysis suggests that this mutation upregulates the expression of "eat-me" signals, MerTK and CD36, and identifies STAT6 as a key transcription factor involved in this process. In conclusion, SIRPα plays a central role in regulating microglia efferocytosis and neuroinflammation after SAH via the SHP1/STAT6 axis. Targeting this pathway may provide a promising therapeutic approach for SAH.

New insights into cancer immune checkpoints landscape from single-cell RNA sequencing

Immune checkpoint blockade (ICB) therapy represents a pivotal advancement in tumor immunotherapy by restoring the cytotoxic lymphocytes' anti-tumor activity through the modulation of immune checkpoint functions. Nevertheless, many patients experience suboptimal therapeutic outcomes, likely due to the immunosuppressive tumor microenvironment, drug resistance, and other factors. Single-cell RNA sequencing has assisted to precisely investigate the immune infiltration patterns before and after ICB treatment, enabling a high-resolution depiction of previously unrecognized functional interaction among immune checkpoints. This review addresses the heterogeneity between tumor microenvironments that respond to or resist ICB therapy, highlighting critical factors underlying the variation in immunotherapy efficacy and elucidating treatment failure. Furthermore, a comprehensive examination is provided of how specific ICBs modulate immune and tumor cells to achieve anti-tumor effects and generate treatment resistance, alongside a summary of emerging immune checkpoints identified as promising targets for cancer immunotherapy through single-cell RNA sequencing applications.

Regulation of macrophage efferocytosis by the CLCF1/NF-κB pathway improves neurological and cognitive impairment following CO poisoning

Severe carbon monoxide (CO) poisoning can induce structural and functional damage to the nervous system, resulting in persistent cognitive impairments. Properly terminating inflammation caused by neuronal damage is essential for tissue repair. Macrophages clear cell corpses and fragments through efferocytosis and produce cytokines to coordinate the immune response, thus promoting neuronal repair and regeneration. However, within the microenvironment of the CO-affected nervous system, macrophage efferocytosis is disrupted. Our study found that macrophages regulate efferocytosis by releasing Cardiotrophin-like cytokine factor 1 (CLCF1), which modulates the NF-κB pathway in both macrophages and microglia, thereby controlling inflammation and promoting nervous system repair. Furthermore, efferocytosis regulates the secretion of cytokines such as TNF-α, IL-1β, and IL-10, promoting M2 polarization of macrophages, which aids in neuronal repair and regeneration. Regulating macrophage CLCF1 expression also leads to improvements in the memory, learning, and motor abilities of rats poisoned with CO.

Antitumor Research Based on Drug Delivery Carriers: Reversing the Polarization of Tumor-Associated Macrophages

The development of malignant tumors is a complex process that involves the tumor microenvironment (TME). An immunosuppressive TME presents significant challenges to current cancer therapies, serving as a key mechanism through which tumor cells evade immune detection and play a crucial role in tumor progression and metastasis. This impedes the optimal effectiveness of immunotherapeutic approaches, including cytokines, immune checkpoint inhibitors, and cancer vaccines. Tumor-associated macrophages (TAMs), a major component of tumor-infiltrating immune cells, exhibit dual functionalities: M1-like TAMs suppress tumorigenesis, while M2-like TAMs promote tumor growth and metastasis. Consequently, the development of various nanocarriers aimed at polarizing M2-like TAMs to M1-like phenotypes through distinct mechanisms has emerged as a promising therapeutic strategy to inhibit tumor immune escape and enhance antitumor responses. This Review covers the origin and types of TAMs, common pathways regulating macrophage polarization, the role of TAMs in tumor progression, and therapeutic strategies targeting TAMs, aiming to provide a comprehensive understanding and guidance for future research and clinical applications.

Multidimensional applications of prussian blue-based nanoparticles in cancer immunotherapy

Immunotherapy holds notable progress in the treatment of cancer. However, the clinical therapeutic effect remains a significant challenge due to immune-related side effects, poor immunogenicity, and immunosuppressive microenvironment. Nanoparticles have emerged as a revolutionary tool to surmount these obstacles and amplify the potency of immunotherapeutic agents. Prussian blue nanoparticles (PBNPs) exhibit multi-dimensional immune function in cancer immunotherapy, including acting as a nanocarrier to deliver immunotherapeutic agents, as a photothermal agent to improve the efficacy of immunotherapy through photothermal therapy, as a nanozyme to regulate tumor microenvironment, and as an iron donor to induce immune events related to ferroptosis and tumor-associated macrophages polarization. This review focuses on the advances and applications of PBNPs in cancer immunotherapy. First, the biomedical functions of PBNPs are introduced. Then, based on the immune function of PBNPs, we systematically reviewed the multidimensional application of PBNPs in cancer immunotherapy. Finally, the challenges and future developments of PBNPs-based cancer immunotherapy are highlighted.

Involvement of the ubiquitin-proteasome system in the regulation of the tumor microenvironment and progression

The tumor microenvironment is a complex environment comprising tumor cells, non-tumor cells, and other critical non-cellular components. Some studies about tumor microenvironment have recently achieved remarkable progress in tumor treatment. As a substantial part of post-translational protein modification, ubiquitination is a crucial player in maintaining protein stability in cell signaling, cell growth, and a series of cellular life activities, which are also essential for regulating tumor cells or other non-tumor cells in the tumor microenvironment. This review focuses on the role and function of ubiquitination and deubiquitination modification in the tumor microenvironment while discussing the prospect of developing inhibitors targeting ubiquity-related enzymes, thereby providing ideas for future research in cancer therapy.

Blebbisomes are large, organelle-rich extracellular vesicles with cell-like properties

Cells secrete a large variety of extracellular vesicles (EVs) to engage in cell-to-cell and cell-to-environment intercellular communication. EVs are functionally involved in many physiological and pathological processes by interacting with cells that facilitate transfer of proteins, lipids and genetic information. However, our knowledge of EVs is incomplete. Here we show that cells actively release exceptionally large (up to 20 µm) membrane-enclosed vesicles that exhibit active blebbing behavior, and we, therefore, have termed them blebbisomes. Blebbisomes contain an array of cellular organelles that include functional mitochondria and multivesicular endosomes, yet lack a definable nucleus. We show that blebbisomes can both secrete and internalize exosomes and microvesicles. Blebbisomes are released from normal and cancer cells, can be observed by direct imaging of cancer cells in vivo and are present in normal bone marrow. We demonstrate that cancer-derived blebbisomes contain a plethora of inhibitory immune checkpoint proteins, including PD-L1, PD-L2, B7-H3, VISTA, PVR and HLA-E. These data identify a very large, organelle-containing functional EV that act as cell-autonomous mobile communication centres capable of integrating and responding to signals in the extracellular environment.

Vascular-Associated Mononuclear Phagocytes: First-Line Soldiers Ambushing Metastasis

Mononuclear phagocytes (MPs), which consist of dendritic cells, monocytes, and macrophages, are distributed throughout the body and actively eliminate invading microorganisms and abnormal cells. Depending on the local microenvironment, MPs manifest considerably various lifespans and phenotypes to maintain tissue homeostasis. Vascular-associated mononuclear phagocytes (VaMPs) are the special subsets of MPs that are localized either within the lumen side or on the apical surface of vessels, acting as the critical sentinels to recognize and defend against disseminated tumor cells. In this review, we introduce three major types of VaMPs, patrolling monocytes, Kupffer cells, and perivascular macrophages, and discuss their emerging roles in immunosurveillance during incipient metastasis. We also explore the roles of lineage-determining transcription factors and cell surface receptors that endow VaMPs with potent anti-tumor activity. Finally, we highlight the molecular and cellular mechanisms that drive the phenotypic plasticity of VaMPs and summarize combinatory strategies for targeting VaMPs in overt metastasis.

Identification and multi-omics analysis of essential coding and long non-coding genes in colorectal cancer

Essential genes are indispensable for the survival of cancer cell. CRISPR/Cas9-based pooled genetic screens have distinguished the essential genes and their functions in distinct cellular processes. Nevertheless, the landscape of essential genes at the single cell levels and the effect on the tumor microenvironment (TME) remains limited. Here, we identified 396 essential protein-coding genes (ESPs) by integration of 8 genome-wide CRISPR loss-of-function screen datasets of colorectal cancer (CRC) cell lines and single-cell RNA sequencing (scRNA-seq) data of CRC tissues. Then, 29 essential long non-coding genes (ESLs) were predicted using Hypergeometric Test (HT) and Personalized PageRank (PPR) algorithms based on ESPs and co-expressed network constructed from scRNA-seq. CRISPR/Cas9 knockout experiment verified the effect of several ESPs and ESLs on the survival of CRC cell line. Furthermore, multi-omics features of ESPs and ESLs were illustrated by examining their expression patterns and transcription factor (TF) regulatory network at the single cell level, as well as DNA mutation and DNA methylation events at bulk level. Finally, through integrating multiple intracellular regulatory networks with cell-cell communication network (CCN), we elucidated that CD47 and MIF are regulated by multiple CRC essential genes, and the anti-cancer drugs sunitinib can interfere the expression of them potentially. Our findings provide a comprehensive asset of CRC ESPs and ESLs, sheding light on the mining of potential therapy targets for CRC.

Targeting novel regulated cell death: disulfidptosis in cancer immunotherapy with immune checkpoint inhibitors

The battle against cancer has evolved over centuries, from the early stages of surgical resection to contemporary treatments including chemotherapy, radiation, targeted therapies, and immunotherapies. Despite significant advances in cancer treatment over recent decades, these therapies remain limited by various challenges. Immune checkpoint inhibitors (ICIs), a cornerstone of tumor immunotherapy, have emerged as one of the most promising advancements in cancer treatment. Although ICIs, such as CTLA-4 and PD-1/PD-L1 inhibitors, have demonstrated clinical efficacy, their therapeutic impact remains suboptimal due to patient-specific variability and tumor immune resistance. Cell death is a fundamental process for maintaining tissue homeostasis and function. Recent research highlights that the combination of induced regulatory cell death (RCD) and ICIs can substantially enhance anti-tumor responses across multiple cancer types. In cells exhibiting high levels of recombinant solute carrier family 7 member 11 (SLC7A11) protein, glucose deprivation triggers a programmed cell death (PCD) pathway characterized by disulfide bond formation and REDOX (reduction-oxidation) reactions, termed "disulfidptosis." Studies suggest that disulfidptosis plays a critical role in the therapeutic efficacy of SLC7A11high cancers. Therefore, to investigate the potential synergy between disulfidptosis and ICIs, this study will explore the mechanisms of both processes in tumor progression, with the goal of enhancing the anti-tumor immune response of ICIs by targeting the intracellular disulfidptosis pathway.

Expression of SIRPα-Fc by oncolytic virus enhances antitumor efficacy through tumor microenvironment reprogramming

Oncolytic viruses (OVs) selectively replicate within tumors, directly killing cancer cells and promoting a systemic immune response by releasing tumor antigens. These features make OVs a promising approach in tumor immunotherapy, offering targeted treatment with fewer side effects. Despite these advantages, OVs are primarily administered via intratumoral injection, limiting their effectiveness for advanced, systemic cancers. Among OVs, oncolytic adenoviruses (oAdVs) are the most widely studied due to their well-understood gene regulation, safety, and stability. In this study, a modified oAdV vector, pDC316-oAd-SA, was engineered to express the SIRPα-mIgG1Fc gene, designed to remodel tumor-associated macrophages (TAMs) and enhance anti-tumor immunity. This vector, along with a control virus (Ad-ON), was evaluated both in vitro and in vivo. The modified oAd-SA significantly improved macrophage phagocytosis and showed superior tumor regression in murine models. Additionally, while both oAdVs increased T cell infiltration in the tumor microenvironment, oAd-SA specifically enhanced T cell immune function. The study also revealed that oAdVs modulate TAMs differently across tumor types, with oAd-SA therapy particularly increasing TAM phagocytosis and promoting an anti-tumor response.

Cooperation between inhibitory immune checkpoints of senescent cells with immunosuppressive network to promote immunosenescence and the aging process

The accumulation of senescent cells within tissues promotes the aging process by remodelling the functions of the immune system. For many years, it has been known that senescent cells secrete pro-inflammatory cytokines and chemokines, a phenotype called the senescence-associated secretory phenotype (SASP). Chemokines and colony-stimulating factors stimulate myelopoiesis and recruit myeloid cells into aging tissues. Interestingly, recent studies have demonstrated that senescent cells are not only secretory but they also express an increased level of ligand proteins for many inhibitory immune checkpoint receptors. These ligands represent "don't eat me" markers in senescent cells and moreover, they are able to induce an exhaustion of many immune cells, such as surveying natural killer (NK) cells, cytotoxic CD8+ T cells, and macrophages. The programmed cell death protein-1 (PD-1) and its ligand PD-L1 represent the best known inhibitory immune checkpoint pathway. Importantly, the activation of inhibitory checkpoint receptors, e.g., in chronic inflammatory states, can also induce certain immune cells to differentiate toward their immunosuppressive phenotype. This can be observed in myeloid derived suppressor cells (MDSC), tissue regulatory T cells (Treg), and M2 macrophages. Conversely, these immunosuppressive cells stimulate in senescent cells the expression of many ligand proteins for inhibitory checkpoint receptors. Paradoxically, senescent cells not only promote the pro-inflammatory state but they maintain it at a low-grade level by expressing ligands for inhibitory immune checkpoint receptors. Thus, the cooperation between senescent cells and immunosuppressive cells enhances the senescence state of immune cells, i.e., immune senescence/exhaustion, and cellular senescence within tissues via bystander effects.

A Dual Stimuli-Responsive Nanoimmunomodulator for Antitumor Synergy of Macrophages and T Cells

Only a minority of patients benefit from current T-cell-focused adaptive immunotherapies, underscoring the need to engage innate immune cells, particularly macrophages, for multilayered tumor control. However, high-efficacy therapeutics capable of orchestrating multiple immune cells remain scarce. Herein, a dual stimuli-responsive nanoimmunomodulator (6EPP@si) that caters specifically to the tumor microenvironment (TME) is presented for the antitumor synergy of macrophages and T cells. Using the functional polymer-based carrier, we co-deliver the endoplasmic reticulum (ER)-localized photosensitizer 6E and small interfering RNA targeting CD47 (siCD47) into breast tumors. Within the acidic and high-glutathione TME, 6EPP@si undergoes self-lysosome escape and nanocleavage for precise, on-demand drug release. Consequently, siCD47 released into the cytoplasm enables potent CD47 silencing, while the ER-targeted photosensitizer 6E induces immunogenic cell death through reactive oxygen species-based ER stress, triggering the release of damage-associated molecular patterns, including calreticulin surface translocation. 6EPP@si enhances macrophage phagocytosis by modulating both antiphagocytic and prophagocytic signals and also promotes antigen presentation to activate T cells. In orthotopic breast tumor and spontaneous lung metastatic tumor models, this combined approach demonstrates robust antitumor effects and effective antimetastatic immunity, offering a meaningful strategy to simultaneously activate multiple immune cells for enhancing cancer immunotherapy.

Biofilm-modified Prussian blue improves memory function in late-stage Alzheimer's disease mice with triple therapy

Alzheimer's disease (AD) is a neurodegenerative disease that is significantly characterized by cognitive and memory impairments, which worsen significantly with age. In the late stages of AD, metal ion disorders and an imbalance of reactive oxygen species (ROS) levels occur in the brain microenvironment, which causes abnormal aggregation of β-amyloid (Aβ), leading to a significant worsening of the AD symptoms. Therefore, we designed a composite nanomaterial of macrophage membranes-encapsulated Prussian blue nanoparticles (PB NPs/MM). Prussian blue nanoparticles (PB NPs) are capable of chelating Cu2+ and reducing ROS. Macrophage membranes (MM) have advantages over liposomal and erythrocyte membrane carriers, including inflammatory targeting capabilities and more effective immune evasion. Concurrently, the excellent photothermal ability of PB NPs can briefly open the blood-brain barrier (BBB) under near-infrared laser irradiation, which improves the transport efficiency of PB NPs/MM across the BBB and ablates Aβ deposition, thus achieving optimal therapeutic efficacy. In vitro experiments demonstrated that PB NPs/MM is a multifunctional nanosystem, which can effectively inhibit Cu2+-induced Aβ monomers aggregation, photothermally depolymerize Aβ fibrils, and attenuate oxidative stress through the combined treatment of chelating metals, photothermal therapy and scavenging ROS. In behavioral experiments, it also significantly improved the cognitive and learning deficits in late-stage APP/PS1 mice, thereby providing new ideas for the treatment of late-stage AD and other neurodegenerative diseases.

Role of glutaminyl-peptide cyclo-transferase-like protein (QPCTL) in cancer: From molecular mechanisms to immunotherapy

Glutaminyl-peptide cyclotransferase-like protein (QPCTL) is a newly discovered enzyme that has sparked interest owing to its possible role in cancer genesis and progression. Initially discovered as a post-translational modification regulator of protein maturation, QPCTL has emerged as a key participant in cancer biology. Recent research has linked QPCTL to numerous essential cancer-related processes, including cell proliferation, migration, invasion, and apoptosis. Furthermore, QPCTL expression changes have been seen in a variety of cancer types, underlining its potential as a diagnostic and prognostic marker. The molecular mechanisms behind QPCTL's participation in cancer will be examined in this review. We investigate its involvement in the control of signaling pathways and the modification of cellular activities that are important in cancer. We also examine the clinical importance of QPCTL, including as its relationship with tumor development, metastasis, and response to treatment. We also discuss the possible therapeutic implications of targeting QPCTL in cancer therapy. QPCTL is a prospective target for the development of innovative anticancer treatments due to its participation in several cancer-associated pathways.

Peptide-Based Complex Coacervates Stabilized by Cation-π Interactions for Cell Engineering

Complex coacervation is a form of liquid-liquid phase separation, whereby two types of macromolecules, usually bearing opposite net charges, self-assemble into dense microdroplets driven by weak molecular interactions. Peptide-based coacervates have recently emerged as promising carriers to deliver large macromolecules (nucleic acids, proteins and complex thereof) inside cells. Thus, it is essential to understand their assembly/disassembly mechanisms at the molecular level in order to tune the thermodynamics of coacervates formation and the kinetics of cargo release upon entering the cell. In this study, we designed histidine-rich peptides consisting of modular sequences in which we systematically incorporate cationic, anionic, or aromatic residues at specific positions along the sequence in order to modulate intermolecular interactions and the resulting coacervation stability. We show that cation-π interactions between arginine and aromatic side chains are particularly efficient in stabilizing complex coacervates, and these interactions can be disrupted in the protein-rich intracellular environment, triggering the disassembly of complex coacervates followed by cargo release. With the additional grafting of a disulfide-based self-immolative side chain, these complex coacervates exhibited enhanced stability and could deliver proteins, mRNA, and CRISPR/Cas9 genome editing tools with tunable release kinetics into cells. This capability extends to challenging cell types, such as macrophages. Our study highlights the critical role of cation-π interactions in the design of peptide-based coacervates, expanding the biomedical and biotechnology potential of this emerging intracellular delivery platform.

MMP2 enzyme-responsive extracellular vesicles as dual-targeted carriers to promote the phagocytosis of macrophages

Combination therapy using inhibition of tumor cell escape and alteration of the tumor microenvironment offers a new strategy for cancer treatment. This study aimed to develop an extracellular vesicle (EV) carrier that regulates tumor cells and the tumor microenvironment to achieve efficient tumor immunotherapy. The ligand modified on carriers targets the immune checkpoint CD47 protein, blocking tumor cell escape. This ligand is cleaved by the MMP2 enzyme and assembles into nanofibers, extending the retention time in the tumor. The carriers target the CD206 protein, enabling efficient uptake by M2 macrophages. Carriers with a high density of ligands (anti-CD206) exhibit strong receptorligand interactions with tumor cells. Due to their high rigidity, these EVs have difficulty deforming during the transmembrane process, reducing resistance and resulting in low uptake efficiency by M2 cells. The optimal uptake efficiency by M2 macrophages is achieved when the mass ratio of ligand to EVs is 1:25. Crocin loaded in EVs facilitates the polarization of M2 macrophages into M1 cells, which can phagocytize tumor cells. This study reveals a potential strategy for using extracellular vesicles in tumor treatment.

Promoting macrophage phagocytosis of cancer cells for effective cancer immunotherapy

Cancer therapy has been revolutionized by immunotherapeutic agents exploiting adaptive antitumor immunity in the past two decades. However, the overall response rate of these immunotherapies is limited, and patients also develop resistance upon treatment, promoting a rapidly growing exploration of anti-tumor innate immunity for effective cancer therapy. Among these, macrophage immunotherapy through harnessing macrophage phagocytosis has been thrust into the spotlight due to its potential for simultaneously inducing cancer cell killing effect and mobilizing adaptive antitumor responses. Here in this review, we summarize the current macrophage immunotherapy such as therapeutic antibodies, phagocytosis checkpoint blockades, and CAR-macrophages with a particular emphasis on the resistant mechanisms limiting their therapeutic effects. Moreover, we further survey the efforts being placed to seek synergistic mechanisms and combination strategies for promoting macrophage phagocytosis which might stand as next-generation cancer immunotherapy.

Efferocytosis: The Janus-Faced Gatekeeper of Aging and Tumor Fate

From embryogenesis to aging, billions of cells perish daily in mammals. The multistep process by which phagocytes engulf these deceased cells without eliciting an inflammatory response is called efferocytosis. Despite significant insights into the fundamental mechanisms of efferocytosis, its implications in disorders such as aging and cancer remain elusive. Upon summarizing and analyzing existing studies on efferocytosis, it becomes evident that efferocytosis is our friend in resolving inflammation, yet it transforms into our foe by facilitating tumor development and metastasis. This review illuminates recent discoveries regarding the emerging mechanisms of efferocytosis in clearing apoptotic cells, explores its connections with aging, examines its influence on tumor development and metastasis, and identifies the regulatory factors of efferocytosis within the tumor microenvironment. A comprehensive understanding of these efferocytosis facets offers insights into crucial physiological and pathophysiological processes, paving the way for innovative therapeutic approaches to combat aging and cancer.

Targeting QPCTL: An Emerging Therapeutic Opportunity

Glutaminyl cyclases, including glutaminyl-peptide cyclotransferase (QPCT) and glutaminyl-peptide cyclotransferase-like protein (QPCTL), primarily catalyze the cyclization of N-terminal glutamine or glutamate to pyroglutamate (pGlu). QPCTL, in particular, modifies the N-terminus of CD47, thereby regulating its interaction with signal-regulatory protein alpha (SIRPα) and modulating phagocytosis of tumor cells by immune cells. Additionally, QPCTL cyclizes the N-termini of CCL2, CCL7, and CX3CL1, influencing the tumor microenvironment and inflammatory responses in cancer and other disorders. Consequently, QPCTL is considered a valuable therapeutic target for several human diseases. However, the development of QPCTL inhibitors remains in its early stages. This perspective summarizes the structural features, catalytic mechanisms, and biological functions of QPCTL, along with its recent advances in small-molecule inhibitors. It provides valuable insights into the development of novel QPCTL inhibitors.

Microenvironment-confined kinetic elucidation and implementation of a DNA nano-phage with a shielded internal computing layer

Multiple receptor analysis-based DNA molecular computation has been developed to mitigate the off-target effect caused by nonspecific expression of cell membrane receptors. However, it is quite difficult to involve nanobodies into molecular computation with programmed recognition order because of the "always-on" response mode and the inconvenient molecular programming. Here we propose a spatial segregation-based molecular computing strategy with a shielded internal computing layer termed DNA nano-phage (DNP) to program nanobody into DNA molecular computation and build a series of kinetic models to elucidate the mechanism of microenvironment-confinement. We explain the contradiction between fast molecular diffusion and effective DNA computation using a "diffusion trap" theory and comprehensively overcome the kinetic bottleneck of DNP by determining the rate-limiting step. We predict and verify that identifying trace amount of target cells in complex cell mixtures is an intrinsic merit of microenvironment-confined DNA computation. Finally, we show that DNP can efficiently work in complex human blood samples by shielding the interference of erythrocytes and enhance phagocytosis of macrophages toward target cells by blocking CD47-SIRPα pathway.

Optimizing antibody stability and efficacy in CD47- SIRPα inhibition via computational approaches

CD47, a cell surface protein, serves as a "don't eat me" signal that prevents immune cells from engulfing healthy cells upon its interaction with SIRPα. Cancer cells exploit this mechanism by overexpressing CD47 to evade immune destruction. Blocking the interaction between CD47 and its receptor, SIRPα, is a promising therapeutic strategy. Targeting the interactions between these surface proteins with small molecules is quite challenging, and on the other hand, antibodies offer potential. However, the interactions between antigen (CD47) and antibody (B6H12.2) play a crucial role in this scenario, and increasing the affinity by mutating the interacting residues might impact the inclination and effectiveness of the antibody towards antigen. Thus, this study focuses on designing antibodies with increased affinity and stability towards the antigen compared to the wild-type. Residual scanning calculations were performed to mutate the interacting as well as the hydrophobic residues of the antibody and affinity was assessed. Computational approaches, including antigen-antibody docking studies and molecular dynamics simulations, were employed to evaluate the affinity, stability and therapeutic potential of these modified antibodies.

PD-L1 monoclonal antibody alleviated MI injury of left ventricular function via modulating CD47/SHP2/SIRPα/SYK/FcγR signalings in tumor associated macrophages

To investigate how PD-L1 monoclonal antibodies (mAbs) affect the left ventricular function in mice with myocardial infarction (MI) and through what mechanisms they exert their effects. In vivo experiments were conducted using 27 female BALB/c mice, which were divided equally into 3 groups. Cardiac function was assessed by ultrasound. Heart tissue and breast cancer tumor samples were isolated, and the content of cGAMP was measured using LC-MS/MS. The extent of myocardial infarction was evaluated by Masson staining. In vitro experiments involved dividing macrophages, treated with different inducers, into 8 groups. Protein expression levels in each group were analyzed by Western blotting, and the macrophages were transplanted into experimental mice for observation. In the in vivo experiments, ultrasound examination showed that PD-L1 mAb improved cardiac function in mice with breast cancer and MI. Both cGAMP content measurement and Masson staining results indicated that PD-L1 mAb had a therapeutic effect on mice with breast cancer and MI, improving the infarct condition and slowing tumor progression. In vitro Western blotting analysis revealed that PD-L1 mAb can modulate the CD47/SHP2/SIRPα/SYK/FcγR signaling pathway, thereby affecting breast cancer. Treatment with a STING inhibitor significantly reduced the cGAMP effect, leading to improved left ventricular function in mice with MI. PD-L1 monoclonal antibodies improve left ventricular function in mice with myocardial infarction by modulating the CD47/SHP2/SIRPα/SYK/FcγR signaling pathway in tumor-associated macrophages and inhibiting the expression of cGAMP.

A self-activated and protective module enhances the preclinical performance of allogeneic anti-CD70 CAR-T cells

Introduction

Allogeneic chimeric antigen receptor T (CAR-T) therapy, also known as universal CAR-T (UCAR-T) therapy, offers broad applicability, high production efficiency, and reduced costs, enabling quicker access for patients. However, clinical application remains limited by challenges such as immune rejection, and issues with potency and durability.

Methods

We first screened a safe and effective anti-CD70 scFv to construct anti-CD70 CAR-T cells. Anti-CD70 UCAR-T cells were then generated by knocking out TRAC, B2M, and HLA-DRA. To address the limitations of UCAR-T therapy, we developed an 'all-in-one' self-activated and protective (SAP) module, integrated into the CAR scaffold. The SAP module consists of the CD47 extracellular domain, a mutant interleukin 7 receptor alpha (IL7Rα) transmembrane domain, and the IL7Rα intracellular domain, designed to protect UCAR-T cells from host immune attacks and enhance their survival.

Results

SAP UCAR-T cells demonstrated significantly reduced immune rejection from the innate immune system, as evidenced by enhanced survival and functionality both in vitro and in vivo. The modified UCAR-T cells exhibited improved persistence, with no observed safety concerns. Furthermore, SAP UCAR-T cells maintained process stability during scale-up production, indicating the potential for large-scale manufacturing.

Discussion

Our findings highlight the SAP module as a promising strategy for the preclinical development of anti-CD70 UCAR-T, paving the way for an 'off-the-shelf' cell therapy product.

Macrophage-specific in vivo RNA editing promotes phagocytosis and antitumor immunity in mice

Macrophages play a central role in antitumor immunity, making them an attractive target for gene therapy strategies. However, macrophages are difficult to transfect because of nucleic acid sensors that can trigger the degradation of foreign plasmid DNA. Here, we developed a macrophage-specific editing (MAGE) system by which compact plasmid DNA encoding a CasRx editor can be delivered to macrophages by a poly(β-amino ester) (PBAE) carrier to bypass the DNA sensor and enable RNA editing in vitro and in vivo. We identified a four-arm branched PBAE with 1-(2-aminoethyl)-4-methylpiperazine end-capping (PBAE29) that enables highly efficient macrophage transfection. PBAE29-mediated transfection of cultured macrophages stimulated less inflammatory cytokine production and inflammasome activation compared with traditional lipofectamine or electroporation-mediated plasmid delivery. Transfection efficiency was further improved by delivering CasRx by minicircle plasmid. The MAGE system incorporated a layer of carboxylated-mannan coating to target macrophage mannose receptors and a macrophage-specific promoter for enhanced selectivity. The delivery of CasRx with guide RNA targeting the transcripts for sialic acid-binding immunoglobulin similar to lectin 10 and signal regulatory protein alpha expression resulted in effective protein knockdown, improving macrophage phagocytosis. The MAGE system also showed efficacy in targeting macrophages in vivo, stimulating antitumor immune responses and reducing tumor volume in murine tumor models, including patient-derived pancreatic adenocarcinoma xenografts in humanized mice. In sum, the MAGE system presents a promising platform for in vivo macrophage-specific delivery of RNA editing tools that can be applied as a cancer therapy.

PPAB001, a novel bispecific antibody against CD47 and CD24, enhances anti-PD-L1 efficacy in triple-negative breast cancer via reprogramming tumor-associated macrophages towards M1 phenotype

Triple-negative breast cancer (TNBC) is a biologically aggressive tumor with a strong association with a high recurrence rate and poor prognosis. Although anti-PD-L1 antibody, Tecentriq has been approved by FDA for treating TNBC, the overall response rate (ORR) is still generally less than 20 %. PPAB001 is a novel bispecific antibody simultaneously targeting CD47 and CD24. In the present study, we firstly evaluated the activity of PPAB001 on promoting the phagocytosis of TNBC cell lines. And the efficacy by combination of PPAB001 and Tecentriq was also assessed in TNBC 4T-1 mouse model. Moreover, the expression profiling of macrophage-associated genes and surface markers were evaluated upon the combinatorial treatment by flow cytometry, Western blot and IHC analysis. Cell signaling involved in M1 macrophage polarization was further identified via the analysis of RNA-seq, Western blot and immunofluorescnece. Our results demonstrated that PPAB001 effectively promotes phagocytosis of macrophages against human TNBC cell lines and significantly delayed TNBC tumor growth, especially when combined with Tecentriq treatment which may be attributed to the mechanism that simultaneous blockade of CD47 and CD24 signaling maximized the polarization toward M1 phenotype polarization. Especially, RNA-seq analysis and Western blotting further revealed that CXCL9/10-CXCR3 axis was markedly up-regulated and JAK/STAT1 pathway was activated upon treatment with PPAB001 plus Tecentriq. Overall, our results underscore that simultaneous blockade of CD47 and CD24 is a potential therapeutic option to improve the efficacy of anti-PD-L1 therapy mainly by resetting tumor-associated macrophages toward M1 phenotype.

Targeting macrophages in cancer immunotherapy: Frontiers and challenges

BACKGROUND

Cancer immunotherapy has emerged as a groundbreaking approach in cancer treatment, primarily realized through the manipulation of immune cells, notably T cell adoption and immune checkpoint blockade. Nevertheless, the manipulation of T cells encounters formidable hurdles. Macrophages, serving as the pivotal link between innate and adaptive immunity, play crucial roles in phagocytosis, cytokine secretion, and antigen presentation. Consequently, macrophage-targeted therapies have garnered significant attention.

AIM OF REVIEW

We aim to provide the most cutting-edge insights and future perspectives for macrophage-targeted therapies, fostering the development of novel and effective cancer treatments.

KEY SCIENTIFIC CONCEPTS OF REVIEW

To date, the forefront strategies for macrophage targeting encompass: altering their plasticity, harnessing CAR-macrophages, and targeting phagocytosis checkpoints. Macrophages are characterized by their remarkable diversity and plasticity, offering a unique therapeutic target. In this context, we critically analyze the innovative strategies aimed at transforming macrophages from their M2 (tumor-promoting) to M1 (tumor-suppressing) phenotype. Furthermore, we delve into the design principles, developmental progress, and advantages of CAR-macrophages. Additionally, we illuminate the challenges encountered in targeting phagocytosis checkpoints on macrophages and propose potential strategies to overcome these obstacles.

Targeting immune checkpoints on myeloid cells: current status and future directions

Myeloid cells accumulate extensively in most tumors and play a critical role in immunosuppression of the tumor microenvironment (TME). Like T cells, myeloid cells also express immune checkpoint molecules, which induce the immunosuppressive phenotype of these cells. In this review, we summarize the tumor-promoting function and immune checkpoint expression of four types of myeloid cells: macrophages, neutrophils, dendritic cells, and myeloid-derived suppressor cells, which are the main components of the TME. By summarizing the research status of myeloid checkpoints, we propose that blocking immune checkpoints on myeloid cells might be an effective strategy to reverse the immunosuppressive status of the TME. Moreover, combining nanotechnology, cellular therapy, and bispecific antibodies to achieve precise targeting of myeloid immune checkpoints can help to avoid the adverse effects of systemic administration, ultimately achieving a balance between efficacy and safety in cancer therapy.

The role of inhibitory immune checkpoint receptors in the pathogenesis of Alzheimer's disease

There is mounting evidence that microglial cells have a key role in the pathogenesis of Alzheimer's disease (AD). In AD pathology, microglial cells not only are unable to remove β-amyloid (Aβ) plaques and invading pathogens but also are involved in synaptic pruning, chronic neuroinflammation, and neuronal degeneration. Microglial cells possess many different inhibitory immune checkpoint receptors, such as PD-1, LILRB2-4, Siglecs, and SIRPα receptors, which can be targeted by diverse cell membrane-bound and soluble ligand proteins to suppress the functions of microglia. Interestingly, in the brains of AD patients there are elevated levels of many of the inhibitory ligands acting via these inhibitory checkpoint receptors. For instance, Aβ oligomers, ApoE4, and fibronectin are able to stimulate the LILRB2-4 receptors. Increased deposition of sialoglycans, e.g., gangliosides, inhibits microglial function via Siglec receptors. AD pathology augments the accumulation of senescent cells, which are known to possess a high level of PD-L1 proteins, and thus, they can evade immune surveillance. A decrease in the expression of SIRPα receptor in microglia and its ligand CD47 in neurons enhances the phagocytic pruning of synapses in AD brains. Moreover, cerebral neurons contain inhibitory checkpoint receptors which can inhibit axonal growth, reduce synaptic plasticity, and impair learning and memory. It seems that inappropriate inhibitory immune checkpoint signaling impairs the functions of microglia and neurons thus promoting AD pathogenesis. KEY MESSAGES: Microglial cells have a major role in the pathogenesis of AD. A decline in immune activity of microglia promotes AD pathology. Microglial cells and neurons contain diverse inhibitory immune checkpoint receptors. The level of ligands for inhibitory checkpoint receptors is increased in AD pathology. Impaired signaling of inhibitory immune checkpoint receptors promotes AD pathology.

Molecular heterogeneity and MYC dysregulation in triple-negative breast cancer: genomic advances and therapeutic implications

Triple-negative breast cancer (TNBC) is characterized by a diverse range of molecular features that have been extensively studied. MYC plays a critical role in regulating metabolism, differentiation, proliferation, cell growth, and apoptosis. Dysregulation of MYC is associated with poor prognosis and contributes to the development and progression of breast cancer. A particularly intriguing aspect of TNBC is its association with tumors in BRCA1 mutation carriers, especially in younger women. MYC may also contribute to resistance to adjuvant treatments. For TNBC, targeting MYC-regulated pathways in combination with inhibitors of other carcinogenic pathways offers a promising therapeutic approach. Several signaling pathways regulate TNBC, and targeting these pathways could lead to effective therapeutic strategies for breast cancer. Advances in genomic tools, such as CRISPR-Cas9, next-generation sequencing, and whole-exome sequencing, are revolutionizing breast cancer diagnoses. These technologies have significantly enhanced our understanding of MYC oncogenesis, particularly through CRISPR-Cas9 and NGS. Targeting MYC and its partner MAX could provide valuable insights into TNBC. Moreover, the therapeutic potential of targeting MYC-driven signaling mechanisms and their interactions with other oncogenic pathways, including PI3K/AKT/mTOR and Wnt/β-catenin, is increasingly recognized. Next-generation sequencing and CRISPR-Cas9 represent significant breakthroughs in genomic tools that open new opportunities to explore MYC's role in TNBC and facilitate the development of personalized treatment plans. This review discusses the future clinical applications of personalized treatment strategies for patients with TNBC.

Therapeutic strategies targeting CD47-SIRPα signaling pathway in gastrointestinal cancers treatment

Gastrointestinal (GI) cancers are prevalent globally, with leading incidence and mortality rates among malignant tumors. Despite notable advancements in surgical resection, radiotherapy, and chemotherapy, the overall survival rates remain low. Hence, it is imperative to explore alternative approaches that enhance patient outcomes. Cluster of differentiation 47 (CD47), serving as an early diagnostic marker, is predominantly overexpressed in GI cancers and associated with poor prognosis. Targeting the CD47-signal regulatory protein alpha (SIRPα) signaling pathway may provide a novel strategy for GI cancers treatment. This study summarizes current knowledge of the structure and function of CD47 and SIRPα, their roles in signaling pathways, the prognostic significance of CD47, therapeutic strategies targeting the CD47-SIRPα signaling pathway in GI cancer, and highlights key issues for future investigations.