SIRPα-CD47 Immune Checkpoint Blockade in Anticancer Therapy

Tumor-Intrinsic SIRPA Drives Pyroptosis Evasion in Head and Neck Cancer

Pyroptosis, a gasdermin-mediated immunogenic cell death, has been shown to elicit adaptive antitumor immune responses, thereby augmenting the response to cancer immunotherapy when pyroptosis is therapeutically activated. However, despite increased gasdermin E (GSDME) expression, significant pyroptosis remains elusive in certain tumor types, and the underlying regulatory mechanisms are poorly understood. In this study, we observed high signal regulatory protein α1 (SIRPA) expression in head and neck squamous cell carcinoma (HNSCC) cells, a target in cancer immunotherapy. Intriguingly, SIRPA inhibition markedly augmented pyroptosis activity in tumor tissues and modulated tumor growth in a HNSCC mouse model. Subsequent investigations revealed that SIRPA knockout upregulated GSDME expression and potentiated cisplatin-induced pyroptosis in cancer cells. Integrative transcriptomics and metabolomics analysis suggested that the SIRPA knockout profoundly altered protein ubiquitination and augmented argininosuccinic acid levels in cancer cells. Specifically, we demonstrated that ubiquitin-specific peptidase 18 (USP18), a deubiquitinating enzyme, targets GSDME for deubiquitination and that USP18 knockdown suppressed cisplatin-induced pyroptosis. Notably, we found that succinylation of GSDME, which is mediated by succinyl-CoA, promotes GSDME cleavage without affecting caspase-3 activation. Further experiments indicated that SIRPA expression in tumor cells can decrease the antitumor efficacy of chemotherapy and immunotherapy in HNSCC mouse models. In summary, our findings reveal a novel mechanism of pyroptosis evasion in HNSCC, whereby tumor-intrinsic SIRPA enhances GSDME ubiquitylation and inhibits its succinylation. These insights suggest that inhibiting SIRPA expression may improve the efficacy of immunotherapy for HNSCC by inducing pyroptosis.

Synergistic Provoking of Pyroptosis and STING Pathway by Multifunctional Manganese-Polydopamine Nano-Immunomodulator for Enhanced Renal Cell Carcinoma Immunotherapy

Manganese ions are known to enhance anti-tumor immunity by activating the cGAS-STING signaling pathway. However, precise modulation of the tumor microenvironment using manganese ions remains a challenge. Dopamine, with its controlled release properties within the tumor microenvironment, offers significant potential for precision drug delivery systems. Metastatic renal cell carcinoma (RCC), being refractory to conventional treatments, necessitates innovative therapeutic approaches. In this study, a multifunctional manganese-polydopamine nano-immunomodulator coated with hyaluronic acid (PDA-Mn-HA NPs) is developed. These nanoparticles selectively bind to CD44 molecules, which are highly expressed in tumor-associated macrophages and RCC cells, and release manganese ions in a tumor microenvironment-responsive manner. Treatment with PDA-Mn-HA NPs effectively induces macrophage M1 polarization, triggers the production of pro-inflammatory cytokines and chemokines. Transcriptomic analysis reveals that PDA-Mn-HA NPs polarize and activate macrophages through the reactive oxygen species(ROS)-STING-p38/MAPK signaling pathway. Additionally, PDA-Mn-HA NPs induce ROS-caspase-3/GSDME-dependent pyroptosis in RCC cells via a Fenton-like reaction. In RCC mouse models, PDA-Mn-HA NPs remodel the macrophage-mediated immune microenvironment, enhance immune cell infiltration, and significantly suppress tumor growth. In conclusion, multifunctional PDA-Mn-HA NPs demonstrate translational potential by addressing the limitations of precision manganese delivery and achieving synergistic targeting of macrophages and tumor cells, offering a promising therapeutic strategy for RCC.

USP2 inhibition unleashes CD47-restrained phagocytosis and enhances anti-tumor immunity

The CD47/SIRPα axis conveys a 'don't eat me' signal, thereby thwarting the phagocytic clearance of tumor cells. Although blocking antibodies targeting CD47 have demonstrated promising anti-tumor effects in preclinical models, clinical trials involving human cancer patients have not yielded ideal results. Exploring the regulatory mechanisms of CD47 is imperative for devising more efficacious combinational therapies. Here, we report that inhibiting USP2 prompts CD47 degradation and reshapes the tumor microenvironment (TME), thereby enhancing anti-PD-1 immunotherapy. Mechanistically, USP2 interacts with CD47, stabilizing it through deubiquitination. USP2 inhibition destabilizes CD47, thereby boosting macrophage phagocytosis. Single-cell RNA sequencing shows USP2 inhibition reprograms TME, evidenced by increasing M1 macrophages and CD8+ T cells while reducing M2 macrophages. Combining ML364 with anti-PD-1 reduces tumor burden in mouse models. Clinically, low USP2 expression predicts a better response to anti-PD-1 treatment. Our findings uncover the regulatory mechanism of CD47 by USP2 and targeting this axis boosts anti-tumor immunity.

Engineered Bacterial Outer Membrane Vesicles Hitchhiking on Neutrophils for Antibody Drug Delivery to Enhance Postoperative Immune Checkpoint Therapy

In clinical practice, surgical removal of tumors often leaves behind small tumors and circulating tumor cells, increasing the risk of metastasis and recurrence, which seriously affects treatment outcomes. Immunotherapy activates the immune system to monitor and inhibit tumor metastasis and recurrence long-term. However, inflammatory microenvironments at surgical sites lead to immunosuppressive tumor-associated macrophages (TAMs), causing immune evasion. Additionally, tumor cells overexpress the immune checkpoint CD47, further weakening the phagocytic and cytotoxic functions of macrophages. Here, the bacterial outer membrane vesicles (OMV) hitchhiking on neutrophils are utilized to precisely deliver immune checkpoint blockade antibodies to the tumor resection site. Escherichia coli is reprogrammed to express CD47 antibody and used to extract CD47 antibody-containing OMV, followed by insertion of Ce6 photosensitizer into the membrane (OC47-Ce6). Purified autologous neutrophils phagocytose and carry OC47-Ce6 for precise targeting to the postoperative tumor resection site, mediating tumor cell killing, aCD47 release, and tumor-associated antigen presentation by light. In vitro and in vivo experiments demonstrate that OC47-Ce6 enhances TAM phagocytic function through TAM polarization and CD47 blockade. This approach effectively activates T-cell anti-tumor immune responses and significantly reduces the risk of postoperative tumor recurrence and metastasis.

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 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.

LINC01871 facilitates cervical cancer cell migration and immune escape by targeting miR-873-3p/MAP3K2 axis

Cervical cancer (CC) poses a significant threat to women's health and lives worldwide. Emerging evidence indicates that long noncoding RNA LINC01871 is closely associated with immune regulation in CC patients. However, its specific role and underlying mechanisms in CC remain poorly understood. In this study, we examined the expression levels and subcellular localization of LINC01871 in CC cell lines. Functional assays, including transwell migration and invasion assays as well as macrophage phagocytosis assays, were conducted to estimate CC cell invasiveness, migration, and immune response. Western blotting was performed to assess the protein expression of markers associated with epithelial-mesenchymal transition (EMT), immunity, and MAPK signaling. A luciferase reporter assay was used to confirm the interactions between LINC01871, miR-873-3p, and MAP3K2. Additionally, a xenograft mouse model was employed to investigate the in vivo effects of LINC01871 on CC progression. Our results revealed that LINC01871 is highly expressed and predominantly localized in the cytoplasm of CC cell lines. LINC01871 knockdown significantly suppressed CC cell invasion, migration, EMT, and immune escape in vitro and reduced tumor growth in vivo. Mechanistically, LINC01871 was found to interact with miR-873-3p, leading to the upregulation of MAP3K2 and subsequent activation of MAPK signaling. Furthermore, MAP3K2 overexpression rescued the inhibitory effects of LINC01871 silencing on the malignant behaviors of CC cells. In conclusion, LINC01871 facilitates CC metastasis by driving EMT and modulating the immune response via the miR-873-3p/MAP3K2/MAPK signaling pathway.

Synergistic Antitumor Immunotherapy via Mitochondria Regulation in Macrophages and Tumor Cells by an Iridium Photosensitizer

Mitochondrial targeting has emerged as an attractive method for antitumor treatment. However, most of the mitochondria targeted drugs focused on inhibiting tumor cells, while their potential for activation of immune responses in the tumor microenvironment has rarely been described. In this study, we report a photosensitive iridium complex MitoIrL2, which enabled the simultaneous mitochondrial modulation of macrophages and tumor cells to achieve synergistic antitumor immunity. The adjustment of the mitochondrial respiratory chain, HIF-1α, and the NF-κB pathway in macrophages drove the metabolic reprogramming from oxidative phosphorylation (OXPHOS) to glycolysis, converting protumor M2 into the antitumor M1 phenotype. Downregulated expression of immunosuppressive checkpoint SIRPα has also been observed on macrophages. Meanwhile, the mitochondrial targeting MitoIrL2 enhanced the immunogenic cell death of tumor cells and reversed the immunosuppressive tumor microenvironment, which activated the systemic immune response and established long-term immune memory in vivo. This work illustrates a promising strategy to simultaneously regulate macrophages toward the antitumor phenotype and enhance immunogenic cell death in tumor cells for synergistic antitumor immunotherapy.

RASON promotes KRASG12C-driven tumor progression and immune evasion in non-small cell lung cancer

BACKGROUND

KRAS is the most frequently mutated oncogene in human cancers, with KRASG12C being a prevalent driver mutation in 12-13% non-small cell lung cancer (NSCLC) cases. Despite breakthroughs in KRASG12C inhibitors such as sotorasib (AMG-510) and adagrasib (MRTX-849), clinical resistance remains a challenging issue, highlighting the need for deeper understanding of the molecular mechanisms underlying KRASG12C-driven oncogenic signaling in NSCLC. Previously, we identified RASON as a novel regulator of KRASG12D/V signaling in pancreatic cancer. Herein, we aim to explore the role of RASON in KRASG12C-driven NSCLC and its therapeutic potential.

METHODS

Immunohistochemistry analysis of NSCLC patient cohorts was performed to demonstrate the correlation between RASON expression and NSCLC progression. Immunoblotting was performed to evaluate the effects of RASON on KRASG12C downstream signaling. In vitro and in vivo assays including cell proliferation, sphere formation, tumor implantation and genetic mouse models were performed to determine the oncogenic role of RASON. RNA-seq analysis was utilized to identify the key signaling pathway regulated by RASON. Immunofluorescence, immunoprecipitation, nuclear magnetic resonance and biochemistry assays were used to validate the interaction between KRASG12C and RASON. Phagocytosis assay and flow cytometry were conducted to explore the effects of RASON on the tumor immune microenvironment. Pharmacological inhibition in subcutaneous xenograft model was used to determine the therapeutical potential of RASON.

RESULTS

RASON is overexpressed in NSCLC with KRASG12C mutation and correlates with poor patient prognosis. Genetic knockout of RASON significantly reduced lung tumor burden in LSL-KRASG12D; Trp53R172H/+ mice. In KRASG12C-mutant lung cancer cell lines, RASON overexpression enhanced, while CRISPR-mediated knockout suppressed, both in vitro proliferation and in vivo tumor growth. Mechanistically, RASON directly binds KRASG12C, stabilizes it in the GTP-bound hyperactive state and promotes downstream signaling. RASON knockout significantly reduced CD47 expression, enhancing macrophage-mediated phagocytosis and anti-tumor immunity. Therapeutically, antisense oligonucleotides targeting RASON not only exhibited tumor-suppressive effects, but also synergized with the KRASG12C inhibitor AMG-510 to significantly enhance anti-tumor efficacy.

CONCLUSION

This study reveals RASON as a key oncogenic regulator of KRASG12C signaling, driving lung tumorigenesis and progression, and identifies RASON as a promising therapeutic target for KRASG12C mutant non-small cell lung cancer.

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.

Bispecific antibodies (bsAbs) directed against PD-1/PD-L1 and CTLA-4; a mini review

Novel approaches to tumor immunotherapy include adoptive cell immunotherapy, immune checkpoint inhibitors (ICIs), and bispecific antibodies (bsABs). bsABs are members of the antibody family that have the ability to distinguish between two distinct antigens or epitopes on a single antigen. These antibodies show better clinical results than monoclonal antibodies, suggesting that they might be a useful choice for tumor immunotherapy. Additionally, dual blockade immunotherapy targeting PD-1/PD-L1 and CTLA-4 functions at various phases of T cell activation with synergistically increasing immune responses against cancer cells, in contrast to ICI monotherapy, which sometimes displays treatment resistance and limited effectiveness. It has been shown that immune response rates and anti-tumor effects may be increased in a synergistic manner by ICI-based combination therapy. We explore the safety and effectiveness of bsABs and ICIs (especially PD1/PDL1 and CTLA-4) combination treatments in tumor immunotherapy in this study with the goal of offering evidence-based methods for clinical research and tailored tumor identification and management.

Engineered macrophage membrane-coated nanoparticles attenuate calcium oxalate nephrocalcinosis-induced kidney injury by reducing oxidative stress and pyroptosis

Kidney stones are characterized by a high incidence and recurrence rate, leading to kidney injury, which in turn accelerates stone formation and deposition. Increasing evidence have demonstrated that oxidative stress and cell pyroptosis play important role in the calcium oxalate (CaOx) stones induced kidney injury. Currently, treatments related to oxidative stress and inflammation associated with kidney stones are still relatively limited. Here, we designed engineered macrophage cell membrane-coated hollow mesoporous manganese dioxide nanoparticles loaded with NLRP3 inhibitors Mcc950 (KM@M@M). KM@M@M NPs were modified with Kim-1 targeting peptides on M2-polarized macrophage membranes to achieve better targeted delivery to injured kidney tubules. Compared with traditional drugs, KM@M@M NPs reduce systemic toxicity through targeted drug delivery to the kidneys. In vivo and in vitro results demonstrate that KM@M@M NPs reduces the activation of the NLRP3 inflammasome in renal tubular epithelial cells by scavenging ROS, thereby downregulating gasdermin D cleavage and the production of inflammatory cytokines, ultimately inhibiting cell pyroptosis. In addition, bioinformatic analysis revealed that KM@M@M NPs protect against CaOx induced kidney injury via suppressing the NLRP3/GSDMD pathway. This article extending the application of engineered cell membrane-based biomimetic nanotechnology, and providing a promising strategy for dual protection in CaOx stones induced kidney injury. STATEMENT OF SIGNIFICANCE: Currently, apart from invasive surgery, there are few pharmacological therapies for CaOx-induced renal injury. This study presents a new strategy using engineered macrophage cell membrane-coated hollow mesoporous manganese dioxide nanoparticles (KM@M@M) to target and treat calcium oxalate (CaOx)-induced kidney injury. The nanoparticles effectively scavenge reactive oxygen species (ROS) and inhibit NLRP3 inflammasome activation, preventing pyroptosis and kidney damage. By delivering NLRP3 inhibitors directly to injured renal tubules, KM@M@M NPs reduce inflammation and stone deposition. This work demonstrates the potential of biomimetic nanotechnology for targeted treatment, offering a promising approach to prevent CaOx-induced renal injury and enhance therapeutic outcomes in kidney stone disease.

Human CSPG4-targeting CAR-macrophages inhibit melanoma growth

Approximately half of melanoma patients relapse or fail to respond to current standards of care, highlighting the need for new treatment options. Engineering T-cells with chimeric antigen receptors (CARs) has revolutionized the treatment of hematological malignancies but has been clinically less effective in solid tumors. We therefore sought to engineer alternative immune cell types to inhibit melanoma progression. Engineering macrophages with CARs has emerged as a promising approach to overcome some of the challenges faced by CAR-T cells; however, whether these engineered macrophages can effectively inhibit melanoma growth is unknown. To determine whether CAR-macrophages (CAR-Ms) specifically target and kill melanoma cells, we engineered CAR-Ms targeting chondroitin sulfate proteoglycan 4 (CSPG4), an antigen expressed in melanoma. CSPG4-targeting CAR-Ms exhibited specific phagocytosis of CSPG4-expressing melanoma cells. We developed 3D approaches to show that CSPG4-targeting CAR-Ms efficiently infiltrated melanoma spheroids. Furthermore, combining CSPG4-targeting CAR-Ms with strategies inhibiting CD47/SIRPα "don't eat me" signaling synergistically enhanced CAR-M-mediated phagocytosis and robustly inhibited melanoma spheroid growth in 3D. Importantly, CSPG4-targeting CAR-Ms inhibited melanoma tumor growth in mouse models. These results suggest engineering macrophages against melanoma antigens is a promising solid tumor immunotherapy approach for treating melanoma.

Dual checkpoint inhibition in M2 macrophages via anti-PD-L1 and siRNA-Loaded M1-Exosomes: Enhancing tumor immunity through RNA-targeting Strategies

The interaction between a cluster of differentiation 47 (CD47) on cancer cells and signal regulatory protein alpha (SIRPα) on macrophages is thought to hinder macrophage phagocytic activity, which can be blocked by combining siRNAs targeting SIRPα (siSIRPα) with simultaneous involvement of activating receptors like FcRs (Fc receptors) using anti-programmed death-ligand 1 (anti-PD-L1). For this study, M1 macrophage-derived exosomes isolated from lipopolysaccharide (LPS)-stimulated RAW264.7 cells were used to deliver the siRNAs, and electroporated with siSIRPα. The exosomes were characterized and used to treat M2 macrophages (RAW264.7 cells triggered by interleukin-4 (IL-4)), and the polarization of macrophages was evaluated using flow cytometry, real-time PCR, ELISA, and phagocytosis assays. The anti-tumor functions of treated macrophages were assessed by co-culturing them with 4T1 cells, evaluating the migration and invasion of 4T1 cells, and examining the phagocytosis of 4T1 cells by macrophages. The results showed that siSIRPα-loaded M1-exosomes caused polarization of M2 macrophage toward M1 phenotype and enhanced anti-tumor effects by reducing migration and invasion of 4T1 cells and enhancing phagocytosis of 4T1 cells by macrophages, especially with combination of anti-PD-L1. This study suggests that blocking the SIRPα-CD47 interaction and the PD-1/PD-L1 pathway in M2 macrophages could be a promising therapeutic approach to enhance anti-tumor immune responses.

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.

Exploring NK cell dynamics and the CD47-SIRPα axis in colon cancer

Inhibitory therapy targeting immune checkpoint regulators, specifically the SIRPα/CD47 axis, has emerged as a promising approach for cancer immunotherapy. SIRPα, which is predominantly expressed in neurons, dendritic cells, macrophages, and NK cells, inhibits professional phagocytes, primarily macrophages, from engulfing self-cells, including tumor cells, through its interaction with the self-recognition marker CD47. Targeting the CD47-SIRPα axis holds therapeutic promise for various cancers, including colorectal cancer. In the present study, we aimed to explore NK cell dynamics and the impact of the CD47/SIRPα axis in patients with colon cancer. We observed a dramatic, time-dependent decrease in NK cell numbers post-surgery, while IFNγ levels, which are indicative of NK cell activity, remained unchanged. Notably, IFNγ levels were significantly lower in patients than in healthy control subjects. In addition, tumors from colorectal cancer patients exhibited low CD47 immunoreactivity. Moreover, postoperative SIRPα levels in NK cells (CD16+/56+ and CD3-) were found to be significantly reduced in colon cancer patients in a gradual manner, regardless of CD47 status. Collectively, our findings reveal the multifaceted role of the CD47/SIRPα axis in colorectal cancer. However, further investigations with larger patient cohorts are warranted to validate these observations.

Unlocking the potential of chimeric antigen receptor T cell engineering immunotherapy: Long road to achieve precise targeted therapy for hepatobiliary pancreatic cancers

Innovative therapeutic strategies are urgently needed to address the ongoing global health concern of hepatobiliary pancreatic malignancies. This review summarizes the latest and most comprehensive research of chimeric antigen receptor (CAR-T) cell engineering immunotherapy for treating hepatobiliary pancreatic cancers. Commencing with an exploration of the distinct anatomical location and the immunosuppressive, hypoxic tumor microenvironment (TME), this review critically assesses the limitations of current CAR-T therapy in hepatobiliary pancreatic cancers and proposes corresponding solutions. Various studies aim at enhancing CAR-T cell efficacy in these cancers through improving T cell persistence, enhancing antigen specificity and reducing tumor heterogeneity, also modulating the immunosuppressive and hypoxic TME. Additionally, the review examines the application of emerging nanoparticles and biotechnologies utilized in CAR-T therapy for these cancers. The results suggest that constructing optimized CAR-T cells to overcome physical barrier, manipulating the TME to relieve immunosuppression and hypoxia, designing CAR-T combination therapies, and selecting the most suitable delivery strategies, all together could collectively enhance the safety of CAR-T engineering and advance the effectiveness of adaptive cell therapy for hepatobiliary pancreatic cancers.

Therapeutic Potential of IL-37 in Cervical Cancer: Suppression of Tumour Progression and Enhancement of CD47-Mediated Macrophage Phagocytosis

As a promising therapeutic approach, immunotherapy is being extensively investigated in cervical cancer. Although immunotherapy has been validated to improve progression-free survival and overall survival in clinical trials, the overall response rate for cervical cancer remains inadequate, necessitating further improvement. Interleukin (IL)-37, an emerging immunomodulator, exhibits antitumour potentials by inhibiting tumour progression and regulating tumour-associated macrophage recognition. We found a significant downregulation of IL-37 expression in cervical cancer, correlated with a poor prognosis. Moreover, the upregulation of IL-37 expression exhibited a suppressive effect on various tumorigenic processes, suppressing the proliferation, invasion, migration, apoptosis and angiogenesis of tumour cells. We also found that the upregulation of IL-37 suppressed cluster of differentiation 47 (CD47) expression in tumour cells via suppression of the signal transducer and activator of transcription 3 (STAT3) expression and phosphorylation, thereby enhancing macrophage recognition and phagocytosis to tumour cells, ultimately reducing immune evasion. Overall, our study highlighted the crucial role of IL-37 in antitumour efficacy and downregulating the expression of CD47 in tumour cells to reduce immune evasion, suggesting the potential of IL-37 as a prognostic biomarker in cervical cancer and offering innovative therapeutic strategies to improve cancer treatment outcomes.

Blocking the SIRPα-CD47 axis promotes macrophage phagocytosis of exosomes derived from visceral adipose tissue and improves inflammation and metabolism in mice

BACKGROUND

Adipose tissue plays a pivotal role in systemic metabolism and maintaining bodily homeostasis. Exosomes from adipose tissues, known as AT-Exos, are recognized as important messengers in the communication between adipose tissue and other organs. Despite this, the alterations in exosome composition and the functional disparities among depot-specific AT-Exos in obesity remain elusive.

METHODS

In this work, we utilized lipidomics and microRNA (miRNA) sequencing to elucidate the lipid and miRNA profiles of AT-Exos in a diet-induced obesity model. We identified obesity-related miRNAs in AT-Exos and further explored their mechanisms using gain- and loss-of-function experiments. To evaluate the metabolic effects of AT-Exos on adipocytes, we conducted RNA-sequencing (RNA-seq) and confirmed our findings through Quantitative Real-time PCR (qPCR) and Western bolt analyses. Meanwhile, a mouse model with intraperitoneal injections was utilized to validate the role of exosomes derived from visceral white adipose tissue (vWAT-Exos) in obesity progression in vivo. Finally, we explored potential therapeutic intervention strategies targeting AT-Exos, particularly focusing on modulating the SIRPα-CD47 axis to enhance macrophage phagocytosis using Leptin-deficient (ob/ob) mice and SIRPα knock-out mice.

RESULTS

Our study revealed that obesity-related metabolism affects the biological processes of AT-Exos, with depot-specific secretion patterns. In obesity, the lipidome profile of AT-Exos was significantly altered, and diet can modify the miRNA content and function within these exosomes, influencing lipid metabolism and inflammatory pathways that contribute to metabolic dysregulation. Specifically, we identified that miR-200a-3p and miR-200b-3p promoted lipid accumulation in 3T3L1 cells partly through the PI3K/AKT/mTOR pathway. RNA-Seq analysis revealed that AT-Exos from different fat depots exerted distinct effects on adipocyte metabolism, with obese vWAT-Exos being notably potent in triggering inflammation and lipid accumulation in diet-induced obesity. Additionally, we found that inhibiting the SIRPα-CD47 axis can mitigate metabolic disorders induced by obese vWAT-Exos or ob/ob mice, partly due to the enhanced clearance of vWAT-Exos. Consistent with this, SIRPα-deficient mice exhibited a reduction in vWAT-Exos and displayed greater resistance to obesity.

CONCLUSIONS

This study elucidates that diet-induced obesity altered the lipid and miRNA profiles of AT-Exos, which involved in modulating adipocyte inflammation and metabolic balance. The SIRPα-CD47 axis emerges as a potential therapeutic target for obesity and its associated complications.

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.

CD47 prevents Rac-mediated phagocytosis through Vav1 dephosphorylation

CD47 is expressed by viable cells to protect against phagocytosis. CD47 is recognized by SIRPα, an inhibitory receptor expressed by macrophages and other myeloid cells. Activated SIRPα recruits SHP-1 and SHP-2 phosphatases but the inhibitory signaling cascade downstream of these phosphatases is not clear. In this study, we used time lapse imaging to measure how CD47 impacts the kinetics of phagocytosis. We found that targets with IgG antibodies were primarily phagocytosed through a Rac-based reaching mechanism. Targets also containing CD47 were only phagocytosed through a less frequent Rho-based sinking mechanism. Hyperactivating Rac2 eliminated the suppressive effect of CD47, suggesting that CD47 prevents activation of Rac and reaching phagocytosis. During IgG-mediated phagocytosis, the tyrosine kinase Syk phosphorylates the GEF Vav, which then activates the GTPase Rac to drive F-actin rearrangement and target internalization. CD47 inhibited Vav1 phosphorylation without impacting Vav1 recruitment to the phagocytic synapse or Syk phosphorylation. Macrophages expressing a hyperactive Vav1 were no longer sensitive to CD47. Together this data suggests that Vav1 is a key target of the CD47 signaling pathway.

Metal-Phenolic Nanomedicines Targeting Fatty Acid Metabolic Reprogramming to Overcome Immunosuppression in Radiometabolic Cancer Therapy

Radiation therapy (RT) is a prevalent cancer treatment; however, its therapeutic outcomes are frequently impeded by tumor radioresistance, largely attributed to metabolic reprogramming characterized by increased fatty acid uptake and oxidation. To overcome this limitation, we developed polyphenol-metal coordination polymer (PPWQ), a novel nanoradiotherapy sensitizer specifically designed to regulate fatty acid metabolism and improve RT efficacy. These nanoparticles (NPs) utilize a metal-phenolic network (MPN) to integrate tungsten ions (W6+), quercetin (QR), and a PD-L1-blocking peptide within a PEG-polyphenol scaffold. When exposed to X-rays, PPWQ induces reactive oxygen species (ROS) to cause DNA damage, while QR inhibits CD36 expression, effectively curbing fatty acid uptake and mitigating immune evasion. In a 4T1 tumor-bearing mouse model, PPWQ demonstrated significant enhancement of RT by facilitating dendritic cell activation, boosting memory cytotoxic T lymphocytes, and skewing macrophages toward a pro-immune phenotype. These results underscore the potential of PPWQ to target metabolic vulnerabilities and advance the integration of immunotherapy with radiotherapy.

Immunomodulation by Leishmania parasites: Potential for controlling other diseases

In the mammalian hosts, Leishmania parasites survive and proliferate within phagolysosomes of macrophages. To avoid being killed by the immune cells, Leishmania parasites utilize their molecules to manipulate macrophages' functions for survival. Targets of such immunomodulatory molecules are not limited to macrophages, as Leishmania-derived molecules sometimes show influence on other immune cells such as neutrophils, dendritic cells, T cells and B cells. This review covers research on immunomodulation of host immunity by Leishmania parasites and introduces some examples of parasite-derived molecules participating in the immunomodulation. For example, Leishmania cell surface lipophosphoglycan (LPG) can modulate TLR2 signaling and PI3K/Akt axis in macrophages leading to induction of Th2 cells. Because chronic secretion of inflammatory cytokines is one of the causes of immune-mediated diseases such as atherosclerosis, Crohn's disease, and rheumatoid arthritis, LPG may be useful as a drug to suppress the inflammatory conditions. The unique characteristics of leishmanial molecules pose a promise as a source of immunomodulatory drugs for controlling diseases other than leishmaniasis.

The clinical significance of signal regulatory protein alpha expression in the immune environment of gastric cancer

BACKGROUND

Signal regulatory protein alpha (SIRPα) inhibits phagocytosis by macrophages by interacting with CD47. Despite its known role in various cancers, the clinical significance of SIRPα in gastric cancer (GC) remains unclear. This study aimed to elucidate the clinical implications of SIRPα in GC, exploring its relevance to immunotherapy efficacy and the tumor microenvironment.

METHODS

Two cohorts were studied: a gastrectomy cohort (137 patients) and an immune checkpoint inhibitor (ICI)-treated cohort (19 patients with unresectable advanced GC who received nivolumab). Immunohistochemistry was used to assess SIRPα, CD80, CD163, CD8, and PD-L1 expressions. Kaplan-Meier curves and Cox models were used to analyze the clinical outcomes. In vitro experiments used peripheral blood mononuclear cells and THP-1 macrophage cell lines to examine SIRPα responses to interferon-γ (IFN-γ).

RESULTS

In the gastrectomy cohort, high SIRPα expression correlated with advanced tumor invasion, distant metastasis, and poor recurrence-free and overall survival. SIRPα expression was also significantly associated with macrophage and CD8 + T cells infiltration and PD-L1 expression. In the ICI-treated cohort, high SIRPα expression was associated with better overall survival after nivolumab induced. Moreover, in vitro IFN-γ stimulation upregulated SIRPα expression on monocytes in peripheral blood mononuclear cells and THP-1 cells, suggesting high SIRPα expression may reflect an active immune microenvironment.

CONCLUSION

SIRPα expression is not only a poor prognostic factor for GC, possibly through inhibition of the CD47-SIRP⍺ pathway, but may also be involved in the efficacy of ICI therapy in GC.

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.

Enhancing the anti-tumor activity and reprogramming M2 macrophages by delivering siRNAs against SIRPα and STAT6 via M1 exosomes and combining with anti-PD-L1

BACKGROUND

The invasive property of breast cancer and the complex composition of the tumor microenvironment (TME) antibodies like anti-PD-L1, can inhibit tumor growth by promoting macrophage phagocytosis. In this research, we used anti-PD-L1 antibody and siRNAs targeting SIRPα (siSIRPα) and STAT6 (siSTAT6). The siRNAs were transported to macrophages using M1-derived exosomes.

METHODS

For this purpose, exosomes were isolated from the supernatant of lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Next, siSIRPα and siSTAT6 were electroporated into the M1-exosomes. M1-exosomes without siRNA or loaded with different siRNAs were used to treat M2 macrophages. Then, the polarization of macrophages was evaluated. By co-culturing of treated macrophages with 4T1 cells, anti-tumor functions of macrophages were assessed.

RESULTS

It was demonstrated that siRNA-loaded M1-exosomes induced macrophage polarization into an M1 phenotype and promoted the anti-tumor effects of macrophages as shown by a reduction in migration, invasion and proliferation of 4T1 cells, as well as an enhancement of phagocytosis of 4T1 cells by macrophages.

CONCLUSION

This study demonstrated the potential of a multifaceted therapeutic approach targeting TAMs to enhance anti-tumor immune responses in breast cancer.

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.

Generation of chimeric antigen receptor-macrophages by using human induced pluripotent stem cells

Cancer immunotherapy using chimeric antigen receptor (CAR) cells shows high therapeutic efficacy against several types of leukemia. Among acute lymphoblastic leukemias (ALLs), B cell-derived ALL can be cured by CAR-expressing T cells (CAR-Ts); however, CAR-T cells cannot be simply applied for T cell-derived ALL (T-ALL) because antigens expressed by T-ALL cells, but not by CAR-T cells, have not yet been identified. To apply CAR-T therapy for T-ALL, gene editing of CAR-T cells is required to avoid attacking CAR-T cells themselves. Alternatively, CAR-expressing macrophages (CAR-Ms) have proven to be effective against various cancers, suggesting that CAR-Ms may also be effective against T-ALL. Recently, we developed an efficient differentiation induction system to generate a large number of macrophages from human induced pluripotent stem cells (iPSCs). Here, we asked whether these human iPSC-derived macrophages (iPS-MACs) can be used to develop and evaluate CAR-based immunotherapy against T-ALLs. When non-transduced iPS-MACs were co-cultured with human T-ALL-derived cells, the iPS-MACs appeared to phagocytose parts of T-ALL cells; this method of phagocytosis operated mainly through incorporation of small, "bite-sized" vesicles derived from the T-ALL cells into iPS-MACs (similar to trogocytosis). By contrast, when CAR-expressing iPS-MACs were co-cultured with T-ALL cells, iPS-MACs engulfed the whole T-ALL cell. Thus, our differentiation induction system may be a promising tool for building up CAR-M therapy for T-ALLs.

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.

Developing CAR T-Cell Therapies for Pediatric Solid Tumors

Chimeric antigen receptor (CAR) T cells have revolutionized the treatment of hematological malignancies, inducing notable and durable clinical responses. However, for solid tumors, including but not limited to pediatric tumors, several peculiar biological features posed substantial challenges for achieving comparable results. Despite sound pre-clinical evidence of the ability of CAR T cells to eradicate solid malignancies, their activity remains suboptimal when facing the in vivo complexity of solid tumors, characterized by antigen heterogeneity, scarce T-cell infiltration, and an immunosuppressive microenvironment. Neuroblastoma was amongst the first tumors to be evaluated as a potential candidate for GD2-targeting CAR T cells, which recently documented promising results in high-risk, heavily pre-treated patients. Moreover, innovative engineering strategies for generating more potent and persistent CAR T cells suggest the possibility to reproduce, and potentially improve, these promising results on a larger scale. In the next years, harnessing the full therapeutic potential of CAR T cells and other immunotherapeutic strategies may open new possibilities for effectively treating the most aggressive forms of pediatric tumors.

Expression and relationship of PD-L1, CD24, and CD47 in hepatitis B virus associated hepatocellular carcinoma

Immune checkpoint inhibitor (ICI) therapy is the new standard treatment for advanced or metastatic hepatocellular carcinoma (HCC); however, many patients still fail to respond. This study explored the expression and prognosis of programmed death ligand 1 (PD-L1), cluster of differentiation 24 (CD24), and cluster of differentiation 47 (CD47) in patients with hepatitis B virus-associated HCC (HBV-associated HCC). We analyzed sequencing data from the Cancer Genome Atlas (TCGA) and investigated the expression of PD-L1, CD24, and CD47 in HBV-associated HCC patients by immunohistochemistry and their relationship with prognosis and clinicopathological factors. HCC data from the TCGA database show that PD-L1 was substantially correlated with various immune cells. In 67 patients with HBV-associated HCC, high PD-L1 and CD24 expression levels were related to poor overall survival (OS) and progression-free survival (PFS). PD-L1 expression was significantly associated with the staging of HBV-associated HCC (p = 0.011) and Ki67 expression (p = 0.024). Correlation analysis between variables reveals that PD-L1 was significantly positively correlated with CD24 and CD47. High expression of PD-L1 and CD24 are risk factors for poor prognosis in HBV-associated HCC patients following curative resection. PD-L1 is significantly correlated with CD24 and CD47.

Signal regulatory protein α dynamically mediates macrophage polarization facilitated alleviation of ischemic diseases

BACKGROUND

macrophage-targeting therapy of ischemic disease has made progress in clinic trial. However, the role and underlying mechanism of pro-inflammatory or anti-inflammatory polarized macrophages in modulating ischemic diseases remain incompletely understood.

RESULTS

here we examine the effect of pro-inflammatory (LPS) and anti-inflammatory (IL-4) macrophage on ischemic diseases in a mouse ischemic hindlimb and heart model, and identify that signal regulatory protein α (Sirpα) modulates macrophage polarization induced angiogenesis via promoting phagocytosis or activating HIF1α nucleus relocation in macrophages, respectively. More importantly, the therapeutic effect of polarized macrophages is controlled by Sirpα in a time-dependent manner. Downregulation of macrophage Sirpα at the early-stage or upregulation of macrophage Sirpα at the late-stage of ischemic disease enhances the therapeutic effect. In contrast, increasing Sirpα at the early-stage or decreasing it at the late-stage leads to failure of inducing ischemic disease resilience. Mechanistically, we find that signal transducer and activator of transcription 3 and 6 (Stat3 and Stat6) mediate downregulation (pro-inflammatory polarization) or upregulation (anti-inflammatory polarization) of Sirpα, respectively.

CONCLUSION

Our results reveal that dynamic regulation of macrophage by Sirpα plays a critical role in alleviating ischemic diseases.

Unveiling the role of RNA methylation in glioma: Mechanisms, prognostic biomarkers, and therapeutic targets

Gliomas, the most prevalent malignant brain tumors in the central nervous system, are marked by rapid growth, high recurrence rates, and poor prognosis. Glioblastoma (GBM) stands out as the most aggressive subtype, characterized by significant heterogeneity. The etiology of gliomas remains elusive. RNA modifications, particularly reversible methylation, play a crucial role in regulating transcription and translation throughout the RNA lifecycle. Increasing evidence highlights the prevalence of RNA methylation in primary central nervous system malignancies, underscoring its pivotal role in glioma pathogenesis. This review focuses on recent findings regarding changes in RNA methylation expression and their effects on glioma development and progression, including N6-methyladenosine (m6A), 5-methylcytosine (m5C), N1-methyladenosine (m1A), and N7-methylguanosine (m7G). Given the extensive roles of RNA methylation in gliomas, the potential of RNA methylation-related regulators as prognostic markers and therapeutic targets was also explored, aiming to enhance clinical management and improve patient outcomes.

Targeting of TAMs: can we be more clever than cancer cells?

АBSTRACT: With increasing incidence and geography, cancer is one of the leading causes of death, reduced quality of life and disability worldwide. Principal progress in the development of new anticancer therapies, in improving the efficiency of immunotherapeutic tools, and in the personification of conventional therapies needs to consider cancer-specific and patient-specific programming of innate immunity. Intratumoral TAMs and their precursors, resident macrophages and monocytes, are principal regulators of tumor progression and therapy resistance. Our review summarizes the accumulated evidence for the subpopulations of TAMs and their increasing number of biomarkers, indicating their predictive value for the clinical parameters of carcinogenesis and therapy resistance, with a focus on solid cancers of non-infectious etiology. We present the state-of-the-art knowledge about the tumor-supporting functions of TAMs at all stages of tumor progression and highlight biomarkers, recently identified by single-cell and spatial analytical methods, that discriminate between tumor-promoting and tumor-inhibiting TAMs, where both subtypes express a combination of prototype M1 and M2 genes. Our review focuses on novel mechanisms involved in the crosstalk among epigenetic, signaling, transcriptional and metabolic pathways in TAMs. Particular attention has been given to the recently identified link between cancer cell metabolism and the epigenetic programming of TAMs by histone lactylation, which can be responsible for the unlimited protumoral programming of TAMs. Finally, we explain how TAMs interfere with currently used anticancer therapeutics and summarize the most advanced data from clinical trials, which we divide into four categories: inhibition of TAM survival and differentiation, inhibition of monocyte/TAM recruitment into tumors, functional reprogramming of TAMs, and genetic enhancement of macrophages.

Anti-tumor and anti-metastatic effects of RRx-001 on hepatocellular carcinoma: mechanisms of action and therapeutic potential

Background

1-Bromoacetyl-3,3-dinitroazetidine (RRx-001) has potent antitumor effects, indicating its promising therapeutic potential against various cancers. This research investigates RRx-001 activity against hepatocellular carcinoma (HCC) and elucidates its underlying mechanisms.

Methods

Huh7, Hepa1-6, and MHCC97H cells were cultured and treated with varying RRx-001 concentrations for 24, 48, and 72 h. Cell viability was assessed using cell counting kit-8. The cells were divided into control and RRx-001 treatment groups at 0.5 × IC50, 1.0 × IC50, and 2.0 × IC50 concentrations for each cell line. Migration and invasion were evaluated using scratch and Transwell assays, and apoptosis was examined by apoptosis assays. RNA sequencing was performed on the Huh7 cells treated with RRx-001 for 24 h to identify differential gene expression. CD47 and TP53 protein levels were measured by Western blot. A xenograft mouse model was utilized to evaluate the effect of RRx-001 on HCC.

Results

RRx-001 inhibits HCC cell viability, migration, and invasion while inducing apoptosis, These effects are potentially mediated by the downregulation of CD47 and the upregulation of TP53, both of which modulate key signaling pathways. In vivo experiments demonstrated that RRx-001 effectively inhibits tumor growth.

Conclusion

RRx-001 reduces the viability of HCC cells and induces apoptosis. This effect may be due to the downregulation of CD47 expression and the alteration of the TP53 protein regulatory pathway.

IMM2520, a novel anti-CD47/PD-L1 bispecific antibody for cancer immune therapy

PD-1/PD-L1 is an important signaling pathway in the adaptive immune system. The CD47/SIRPα signaling pathway is a crucial "do not eat me" signal for innate immunity. This study evaluated the anti-tumor mechanism of IMM2520 in vitro and in vivo. IMM2520 was generated using the "mab-trap" platform. IMM2520 showed high affinity to PD-L1 and relatively lower affinity to CD47, displaying preferential binding to PD-L1 on tumor cells. IMM2520 had the potent ability to inhibit the PD-1/PD-L1 and CD47/SIRPα signaling pathways and killed tumor cells through ADCC and ADCP. Importantly, IMM2520 did not bind to human red blood cells or induce erythrocyte agglutination. IMM2520 demonstrated a tendency to bind to CD47+/PD-L1+ tumor cells, reducing its binding to CD47 single-positive cells. In mouse transplantation models, compared with the first-generation CD47/PD-L1 BsAb (IMM2505), IMM2520 exhibited stronger and dose-dependent antitumor activity. These findings imply that IMM2520 may offer a novel therapeutic alternative for cancer patients.

The novel immune landscape of immune-checkpoint blockade in EBV-associated malignancies

The Epstein-Barr virus (EBV) is a ubiquitous gamma-herpesvirus and a class 1 carcinogen that is closely associated with a series of malignant lymphomas and epithelial cell carcinomas. Although these EBV-related cancers may exhibit different features in clinical symptoms and anatomical sites, they all have a characteristic immune-suppressed tumor immune microenvironment (TIME) that is tightly correlated with an abundance of tumor-infiltrating lymphocytes (TILs) that primarily result from the EBV infection. Overwhelming evidence indicates that an upregulation of immune-checkpoint molecules is a powerful strategy employed by the EBV to escape immune surveillance. While previous studies have mainly focused on the therapeutic effects of PD-1 and CTLA-4 blockades in treating EBV-associated tumors, several novel inhibitory receptors (e.g., CD47, LAG-3, TIM-3, VISTA, and DDR1) have recently been identified as potential targets for treating EBV-associated malignancies (EBVaMs). This review retrospectively summarizes the biological mechanisms used for immune checkpoint evasion in EBV-associated tumors. Its purpose is to update our current knowledge concerning the underlying mechanisms by which an immune checkpoint blockade triggers host antitumor immunity against EBVaMs. Additionally, this review may help investigators to more fully understand the correlation between EBV infection and tumor development and subsequently develop novel therapeutic strategies.

Pancreatic ductal adenocarcinoma cells reshape the immune microenvironment: Molecular mechanisms and therapeutic targets

Pancreatic ductal adenocarcinoma (PDAC) is a digestive system malignancy characterized by challenging early detection, limited treatment alternatives, and generally poor prognosis. Although there have been significant advancements in immunotherapy for hematological malignancies and various solid tumors in recent decades, with impressive outcomes in recent preclinical and clinical trials, the effectiveness of these therapies in treating PDAC continues to be modest. The unique immunological microenvironment of PDAC, especially the abnormal distribution, complex composition, and variable activation states of tumor-infiltrating immune cells, greatly restricts the effectiveness of immunotherapy. Undoubtedly, integrating data from both preclinical models and human studies helps accelerate the identification of reliable molecules and pathways responsive to targeted biological therapies and immunotherapies, thereby continuously optimizing therapeutic combinations. In this review, we delve deeply into how PDAC cells regulate the immune microenvironment through complex signaling networks, affecting the quantity and functional status of immune cells to promote immune escape and tumor progression. Furthermore, we explore the multi-modal immunotherapeutic strategies currently under development, emphasizing the transformation of the immunosuppressive environment into an anti-tumor milieu by targeting specific molecular and cellular pathways, providing insights for the development of novel treatment strategies.

Ultrasound-responsive nanocarriers with siRNA and Fe3O4 regulate macrophage polarization and phagocytosis for augmented non-small cell lung cancer immunotherapy

The immunosuppressive tumor microenvironment (TME) significantly inhibits the effective anti-tumor immune response, greatly affecting the efficacy of immunotherapy. Most tumor-associated macrophages (TAMs) belong to the M2 phenotype, which contributes significantly to the immunosuppressive effects in non-small cell lung cancer (NSCLC) TME. The interaction between signal regulatory protein α (SIRPα) expressed on macrophages and CD47, a transmembrane protein overexpressed on cancer cells, activates the "eat-me-not" signaling pathway, inhibiting phagocytosis. In this study, a folic acid (FA)-modified ultrasound responsive gene/drugs delivery system, named FA@ PFP @ Fe3O4 @LNB-SIRPα siRNA (FA-PFNB-SIRPα siRNA), was developed using 1,2-dioleoacyl-3-trimethylammonium-propane (DOTAP), FA-1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N- [amino (polyethylene glycol)2000] (DSPE-PEG2000-FA), cholesterol, and perfluoropentane (PFP), for the delivery of siRNA encoding SIRPα mRNA and immune adjuvant Fe3O4 nanoparticles. Under ultrasound conditions, the nanobubbles effectively transfected macrophages, inhibiting SIRPα mRNA and protein expression, promoting the phagocytosis of TAMs, and synergistically reversing M2 polarization. This system promotes the infiltration of T cells, enhances the proliferation and activation of cytotoxic T cells, and inhibits the infiltration of immunosuppressive cells in tumor tissues. Administration of FA-PFNB-SIRPα siRNA combined with ultrasound significantly inhibits NSCLC progression. The study highlights the potential of ultrasound nanotechnology-enabled delivery of SIRPα siRNA and Fe3O4 as an effective strategy for macrophage-based immunotherapy to reshape the immunosuppressive TME for cancer therapy.

Delineating the Immunotherapeutic Potential of Vitamin E and Its Analogues in Cancer: A Comprehensive Narrative Review

Cancer is a disease resulting from uncontrolled cell division, which significantly contributes to human mortality rates. An alternative approach to cancer treatment, such as cancer immunotherapy, is needed as the existing chemotherapy and radiotherapy approaches target the cancer cells and healthy dividing cells. Vitamin E is a plant-derived lipid-soluble antioxidant with numerous health-promoting benefits, including anticancer and immunomodulatory properties. Vitamin E comprises eight natural isoforms: tocopherols (α, β, δ, and γ) and tocotrienols (α, β, δ, and γ). While initial research focused on the anticancer properties of α-tocopherol, there is growing interest in other natural forms and modified synthetic analogues of vitamin E due to their unique properties and enhanced anticancer effects. Hence, this review is aimed at outlining the effect of vitamin E and its analogues at various steps of the cancer-immunity cycle that can be used to stimulate anticancer immune responses.

Cell autonomous functions of CD47 in regulating cellular plasticity and metabolic plasticity

CD47 is a ubiquitously expressed cell surface receptor, which is widely known for preventing macrophage-mediated phagocytosis by interacting with signal regulatory protein α (SIRPα) on the surface of macrophages. In addition to its role in phagocytosis, emerging studies have reported numerous noncanonical functions of CD47 that include regulation of various cellular processes such as proliferation, migration, apoptosis, differentiation, stress responses, and metabolism. Despite lacking an extensive cytoplasmic signaling domain, CD47 binds to several cytoplasmic proteins, particularly upon engaging with its secreted matricellular ligand, thrombospondin 1. Indeed, the regulatory functions of CD47 are greatly influenced by its interacting partners. These interactions are often cell- and context-specific, adding a further level of complexity. This review addresses the downstream cell-intrinsic signaling pathways regulated by CD47 in various cell types and environments. Some of the key pathways modulated by this receptor include the PI3K/AKT, MAPK/ERK, and nitric oxide signaling pathways, as well as those implicated in glucose, lipid, and mitochondrial metabolism. These pathways play vital roles in maintaining tissue homeostasis, highlighting the importance of understanding the phagocytosis-independent functions of CD47. Given that CD47 expression is dysregulated in a variety of cancers, improving our understanding of the cell-intrinsic signals regulated by this molecule will help advance the development of CD47-targeted therapies.

2D nanomaterials-based delivery systems and their potentials in anticancer synergistic photo-immunotherapy

As the field of cancer therapeutics evolves, integrating two-dimensional (2D) nanomaterials with photo-immunotherapy has emerged as a promising approach with significant potential to augment cancer treatment efficacy. These 2D nanomaterials include graphene-based 2D nanomaterials, 2D MXenes, 2D layered double hydroxides, black phosphorus nanosheets, 2D metal-organic frameworks, and 2D transition metal dichalcogenides. They exhibit high load capacities, multiple functionalization pathways, optimal biocompatibility, and physiological stability. Predominantly, they function as anti-tumor delivery systems, amalgamating diverse therapeutic modalities, most notably phototherapy and immunotherapy, and the former is a recognized non-invasive treatment modality, and the latter represents the most promising anti-cancer strategy presently accessible. Thus, integrating phototherapy and immunotherapy founded on 2D nanomaterials unveils a novel paradigm in the war against cancer. This review delineates the latest developments in 2D nanomaterials as delivery systems for synergistic photo-immunotherapy in cancer treatment. We elaborate on the burgeoning realm of photo-immunotherapy, exploring the interplay between phototherapy and enhanced immune cells, immune response modulation, or immunosuppressive tumor microenvironments. Notably, the strategies to augment photo-immunotherapy have also been discussed. Finally, we discuss the challenges and future perspectives of these 2D nanomaterials in photo-immunotherapy.

FAT10 induces immune suppression by upregulating PD-L1 expression in hepatocellular carcinoma

The upregulation of programmed death ligand 1 (PD-L1) plays a crucial role in facilitating cancer cells to evade immune surveillance through immunosuppression. However, the precise regulatory mechanisms of PD-L1 in hepatocellular carcinoma (HCC) remain undefined. The correlation between PD-L1 and ubiquitin-like molecules (UBLs) was studied using sequencing data from 20 HCC patients in our center, combined with TCGA data. Specifically, the association between FAT10 and PD-L1 was further validated at both the protein and mRNA levels in HCC tissues from our center. Subsequently, the effect of FAT10 on tumor progression and immune suppression was examined through both in vivo and in vitro experiments. Utilizing sequencing data, qPCR, and Western blotting assays, we confirmed that FAT10 was highly expressed in HCC tissues and positively correlated with PD-L1 expression. Additionally, in vitro experiments demonstrated that the overexpression of FAT10 fostered the proliferation, migration, and invasion of HCC cells. Furthermore, the overexpression of FAT10 in HCC cells led to an increase in PD-L1 expression, resulting in the inhibition of T cell proliferation and the enhancement of HCC cell resistance to T cell-mediated cytotoxicity. Moreover, in vivo experiments utilizing the C57BL/6 mouse model revealed that overexpression of FAT10 effectively suppressed the infiltration of CD8 + GZMB + and CD8 + Ki67 + T cells, as well as reduced serum levels of TNF-α and IFN-γ. Mechanistically, we further identified that FAT10 upregulates PD-L1 expression via activating the PI3K/AKT/mTOR pathway, but not in a ubiquitin-like modification. In conclusion, our findings indicate that FAT10 promotes immune evasion of HCC via upregulating PD-L1 expression, suggesting its potential as a novel target to enhance the efficiency of immunotherapy in HCC.

Deciphering the role of CD47 in cancer immunotherapy

BACKGROUND

Immunotherapy has emerged as a novel strategy for cancer treatment following surgery, radiotherapy, and chemotherapy. Immune checkpoint blockade and Chimeric antigen receptor (CAR)-T cell therapies have been successful in clinical trials. Cancer cells evade immune surveillance by hijacking inhibitory pathways via overexpression of checkpoint genes. The Cluster of Differentiation 47 (CD47) has emerged as a crucial checkpoint for cancer immunotherapy by working as a "don't eat me" signal and suppressing innate immune signaling. Furthermore, CD47 is highly expressed in many cancer types to protect cancer cells from phagocytosis via binding to SIRPα on phagocytes. Targeting CD47 by either interrupting the CD47-SIRPα axis or combing with other therapies has been demonstrated as an encouraging therapeutic strategy in cancer immunotherapy. Antibodies and small molecules that target CD47 have been explored in pre- and clinical trials. However, formidable challenges such as the anemia and palate aggregation cannot be avoided because of the wide presentation of CD47 on erythrocytes.

AIM OF VIEW

This review summarizes the current knowledge on the regulation and function of CD47, and provides a new perspective for immunotherapy targeting CD47. It also highlights the clinical progress of targeting CD47 and discusses challenges and potential strategies.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review provides a comprehensive understanding of targeting CD47 in cancer immunotherapy, it also augments the concept of combination immunotherapy strategies by employing both innate and adaptive immune responses.

A polymeric nanoplatform enhances the cGAS-STING pathway in macrophages to potentiate phagocytosis for cancer immunotherapy

Immunosuppressive tumor-associated macrophages (TAMs) account for a high proportion of the tumor tissue and significantly impede immunoefficacy. Furthermore, the signal regulatory protein α (SIRPα) expressed in TAMs adversely correlates with macrophage activation and phagocytosis, resulting in immunosurveillance escape. To address these difficulties, a mannose-modified, pH-responsive nanoplatform with resiquimod (R848) and 2', 3'-cyclic GMP-AMP (cGAMP) co-encapsulation (named M-PNP@R@C) is designed to polarize TAMs and lower SIRPα expression. The co-delivery of R848 and cGAMP synergistically facilitates the polarization of TAMs from the anti-inflammatory M2 phenotype into the pro-inflammatory M1 phenotype, thereby enhancing antitumor immunotherapy. Remarkably, activation of the cGAMP-mediated stimulator of interferon genes (STING) in TAMs significantly downregulates the expression of SIRPα, which synergizes with the cluster of differentiation 47 (CD47) antibody for the dual blockade of the CD47-SIRPα axis. Further analysis of single-cell RNA sequencing indicates that STING activation downregulates SIRPα by regulating intracellular fatty acid oxidation metabolism. In vivo studies indicate that M-PNP@R@C significantly inhibits tumor growth with a potent antitumor immune response in melanoma graft tumor models. After synergy with anti-CD47, the double blockade strategies of the SIRPα/CD47 axis result in a notable inhibition of lung metastasis. A prolonged survival rate is observed after combination treatment with CD47 and programmed death ligand-1 antibodies for the triple immune checkpoint blockade. In summary, our study provides original insights into the potential role of the STING pathway in macrophage-based immunotherapy, thus offering a potential combinatorial strategy for cancer therapy.

Insights into therapeutic peptides in the cancer-immunity cycle: Update and challenges

Immunotherapies hold immense potential for achieving durable potency and long-term survival opportunities in cancer therapy. As vital biological mediators, peptides with high tissue penetration and superior selectivity offer significant promise for enhancing cancer immunotherapies (CITs). However, physicochemical peptide features such as conformation and stability pose challenges to their on-target efficacy. This review provides a comprehensive overview of recent advancements in therapeutic peptides targeting key steps of the cancer-immunity cycle (CIC), including tumor antigen presentation, immune cell regulation, and immune checkpoint signaling. Particular attention is given to the opportunities and challenges associated with these peptides in boosting CIC within the context of clinical progress. Furthermore, possible future developments in this field are also discussed to provide insights into emerging CITs with robust efficacy and safety profiles.