Macrophage-Based Approaches for Cancer Immunotherapy

Encapsulated mitochondria to reprogram the metabolism of M2-type macrophages for anti-tumor therapy

M2-type macrophages (M2Φ) play a pro-tumorigenic role and are closely associated with tumor development, where metabolic dysregulation exacerbates the immunosuppressive tumor microenvironment and fosters tumor growth. Mitochondria serve as the regulatory center of cellular metabolism, yet effective methods to modulate M2Φ mitochondria within the tumor microenvironment remain lacking. In this study, we developed a technique utilizing the bio-encapsulation of mitochondria in Zeolitic Imidazolate Framework-8 (ZiF-8), referred to as Mito@ZiF-8. Our findings demonstrated that this coating protects intact mitochondria and preserves their bioactivity over an extended period after isolation. We successfully delivered Mito@ZiF-8 into M2Φ, which inhibited the secretion of pro-inflammatory factors, promoted the release of anti-inflammatory factors, and reprogrammed M2Φ metabolism. This innovative approach has the potential to reduce breast cancer cell metastasis and enhance sensitivity to chemotherapy drugs such as 6-thioguanine, cisplatin, and doxorubicin (Dox). Mito@ZiF-8 aims to reprogram the M2Φ microenvironment to support anti-tumor therapies, offering a novel strategy for improving the effectiveness of breast cancer treatment.

Insights into the Identification of iPSC- and Monocyte-Derived Macrophage-Polarizing Compounds by AI-Fueled Cell Painting Analysis Tools

Macrophage polarization critically contributes to a multitude of human pathologies. Hence, modulating macrophage polarization is a promising approach with enormous therapeutic potential. Macrophages are characterized by a remarkable functional and phenotypic plasticity, with pro-inflammatory (M1) and anti-inflammatory (M2) states at the extremes of a multidimensional polarization spectrum. Cell morphology is a major indicator for macrophage activation, describing M1(-like) (rounded) and M2(-like) (elongated) states by different cell shapes. Here, we introduced cell painting of macrophages to better reflect their multifaceted plasticity and associated phenotypes beyond the rigid dichotomous M1/M2 classification. Using high-content imaging, we established deep learning- and feature-based cell painting image analysis tools to elucidate cellular fingerprints that inform about subtle phenotypes of human blood monocyte-derived and iPSC-derived macrophages that are characterized as screening surrogate. Moreover, we show that cell painting feature profiling is suitable for identifying inter-donor variance to describe the relevance of the morphology feature 'cell roundness' and dissect distinct macrophage polarization signatures after stimulation with known biological or small-molecule modulators of macrophage (re-)polarization. Our novel established AI-fueled cell painting analysis tools provide a resource for high-content-based drug screening and candidate profiling, which set the stage for identifying novel modulators for macrophage (re-)polarization in health and disease.

Expression of HECTD2 predicts peritoneal metastasis of gastric cancer and reconstructs immune microenvironment

Peritoneal metastasis (PM) is a common metastasis site and death cause of gastric cancer, which is a complex biological process, but there is currently a lack of effective prediction and treatment targets. In this study, we first analyzed the differential gene expression of gastric cancer patients with or without peritoneal metastasis, and identified the HECT domain E3 ubiquitin protein ligase 2 (HECTD2) as the core gene of PM in gastric cancer. The current study shows that the role of HECTD2 in tumor is contradictory. In this study, our results show that the low expression of HECTD2 indicates that the survival rate of overall survival (OS), progression-free survival (PFS), disease-specific survival (DSS), and disease-free survival (DFS) are better, and can be used as an important component of prognostic indicators. In addition, through pathway enrichment analysis, we found that HECTD2 was mainly involved in metastasis related pathways such as extracellular matrix remodeling and cell adhesion in gastric cancer, and high expression of HECTD2 could activate epithelial-mesenchymal transition (EMT) metastasis related pathways in gastric cancer. In regulating the metastasis of gastric cancer cells, HECTD2 can also change the surrounding microenvironment, induce the enrichment of interstitial components and build an immune microenvironment conducive to tumor progression, while patients with low expression of HECTD2 may be more likely to benefit from immunotherapy. In conclusion, HECTD2 may be a novel biomarker for the diagnosis and prognosis of peritoneal metastasis of gastric cancer, providing basis for the mechanism of peritoneal metastasis of cancer and clinical medication.

In vivo gene editing and in situ generation of chimeric antigen receptor cells for next-generation cancer immunotherapy

Chimeric antigen receptor (CAR) cell therapy has achieved groundbreaking success in treating hematological malignancies. However, its application to solid tumors remains challenging due to complex manufacturing processes, limited in vivo persistence, and transient therapeutic effects. In vivo CAR-immune cells induced by gene delivery systems loaded with CAR genes and gene-editing tools have shown efficiency for anti-tumor immunotherapy. In situ programming of autologous immune cells avoids the safety concerns of allogeneic immune cells, and the manufacture of gene delivery systems could be standardized. Therefore, the in vivo editing and in situ generation of CAR-immune cells might potentially overcome the abovementioned limitations of current CAR cell therapy. This review mainly focuses on CAR structures, gene-editing tools, and gene delivery techniques applied in anti-tumor immunotherapy to help design and develop in situ CAR-immune cell therapy. The recent applications of in vivo CAR-immune cell therapy in both hematologic malignancies and solid tumors are investigated. To sum up, the in vivo editing and in situ generation of CAR therapy holds promise for offering a practical, cost-effective, efficient, safe, and widely applicable approach to the next-generation anti-tumor immunotherapy.

Development of a novel HER2-CAR monocyte cell therapy with controllable proliferation and enhanced anti-tumor efficacy

BACKGROUND

One of the significant challenges for cell therapies, such as chimeric antigen receptor (CAR)-T cell therapy, is the poor infiltration of immune cells into tumor tissues. CAR-monocytes/macrophages (CAR-M) are promising therapies because of their enrichment in the tumor microenvironment. Thus, we constructed a novel CAR-M to facilitate the infiltration of T cells and other immune cells.

METHODS

The suicide gene inducible caspase-9 ( iCasp9 ) and anti-erb-b2 receptor tyrosine kinase 2 (HER2) CAR elements were transfected into THP1 (an immortalized human monocyte cell line) by lentivirus. The suicide efficiency and specific anti-tumor efficacy were assessed using flow cytometry, inCucyte, and tumor-bearing BALB/c-nude mouse models. The activation of related signaling pathways in CAR-THP1 activation was explored by transcriptome sequencing. Finally, the synergistic therapeutic efficacy of CAR-THP1 combined with RAK cell treatment was demonstrated in tumor-bearing NOD.CB17-Prkdc scid Il2rg tm1 /Bcgen mouse models.

RESULTS

We developed a novel CAR-THP1, which incorporated iCasp9, CD3ζ, and CD147 intracellular segments, based on the first-generation HER2-CAR backbone. By constructing and comparing a series of CARs with different permutations, CAR-CD3ζ-CD147-iCasp9-THP1 was selected as the optimal combination. CAR-CD3ζ-CD147-iCasp9-THP1 initiated suicide quickly and efficiently under the control of iCasp9 gene, which enabled us to achieve controlled proliferation of CAR-THP1. CAR-THP1 also exhibited robust specific anti-tumor efficacy independently of T cells in vitro and in vivo . Through transcriptional sequencing, we found that CAR-THP1 tended to differentiate into the M1 phenotype and bridged innate and adaptive immunity. A combination of CAR-THP1 and Retronectin actived killer cells (RAKs) showed better therapeutic efficiency, as the metalloproteinases (MMPs) secreted by CAR-THP1 facilitated the degradation of the dense tumor matrix. This further assisted intratumoral infiltration of T cells and augmented the anti-tumor immune response.

CONCLUSION

CAR-THP1 might be effective against HER2-positive tumor cells and has great potential for combination therapy with other immune cells.

Ginsenoside Re inhibits non-small cell lung cancer progression by suppressing macrophage M2 polarization induced by AMPKα1/STING positive feedback loop

Tumor-associated macrophages (TAMs) in non-small cell lung cancer (NSCLC) promote tumor cell metastasis by interacting with cancer cells. Ginsenoside Re is capable of modulating the host immune system and exerts anticancer effects through multiple pathways. Both AMPK and STING are involved in the regulation of MΦ polarization, thereby affecting tumor progression. However, whether there is a regulatory relationship between them and its effect on MΦ polarization and tumor progression is unclear. The aim of this study was to provide mechanistic evidence that ginsenoside Re modulates MΦ phenotype through inhibition of the AMPKα1/STING positive feedback loop and thus exerts an antimetastatic effect in NSCLC immunotherapy. Cell culture models and conditioned media (CM) systems were constructed, and the treated MΦ were analyzed by database analysis, RT-PCR, Western blotting, flow cytometry, and immunofluorescence to determine the regulatory relationship between AMPK and STING and the effects of ginsenoside Re on MΦ polarization and tumor cells migration. The effects of ginsenoside Re (10, 20 mg/kg/day) on TAMs phenotype as well as tumor progression in mice were assessed by HE staining, immunohistochemical staining, and Western blotting. In this study, AMPKα1/STING positive feedback loop in NSCLC TAMs induced M2 type polarization, which in turn promoted NSCLC cell migration. In addition, ginsenoside Re was discovered to inhibit M2-like MΦ polarization, thereby inhibiting NSCLC cell migration. Mechanistically, Re was able to inhibit the formation of the AMPKα1/STING positive feedback loop, thereby inhibiting its induction of M2-like MΦ and consequently inhibiting the epithelial-mesenchymal transition (EMT) process of NSCLC cells. Furthermore, in mouse models, Re was found to suppress LLC tumor growth and colonization by inhibiting M2-type polarization of TAMs. Our finding indicates that ginsenoside Re can effectively modulate MΦ polarization and thus play an important role in antimetastatic immunotherapy of NSCLC.

Macrophages in tumor cell migration and metastasis

Tumor-associated macrophages (TAMs) are a phenotypically diverse, highly plastic population of cells in the tumor microenvironment (TME) that have long been known to promote cancer progression. In this review, we summarize TAM ontogeny and polarization, and then explore how TAMs enhance tumor cell migration through the TME, thus facilitating metastasis. We also discuss how chemotherapy and host factors including diet, obesity, and race, impact TAM phenotype and cancer progression. In brief, TAMs induce epithelial-mesenchymal transition (EMT) in tumor cells, giving them a migratory phenotype. They promote extracellular matrix (ECM) remodeling, allowing tumor cells to migrate more easily. TAMs also provide chemotactic signals that promote tumor cell directional migration towards blood vessels, and then participate in the signaling cascade at the blood vessel that allows tumor cells to intravasate and disseminate throughout the body. Furthermore, while chemotherapy can repolarize TAMs to induce an anti-tumor response, these cytotoxic drugs can also lead to macrophage-mediated tumor relapse and metastasis. Patient response to chemotherapy may be dependent on patient-specific factors such as diet, obesity, and race, as these factors have been shown to alter macrophage phenotype and affect cancer-related outcomes. More research on how chemotherapy and patient-specific factors impact TAMs and cancer progression is needed to refine treatment strategies for cancer patients.

Construction of a Prognostic Model for Mitochondria and Macrophage Polarization Correlation in Glioma Based on Single-Cell and Transcriptome Sequencing

BACKGROUND

Numerous diseases are associated with the interplay of mitochondrial and macrophage polarization. However, the correlation of mitochondria-related genes (MRGs) and macrophage polarization-related genes (MPRGs) with the prognosis of glioma remains unclear. This study aimed to examine this relationship based on bioinformatic analysis.

METHODS

Glioma-related datasets (TCGA-GBMLGG, mRNA-seq-325, mRNA-seq-693, GSE16011, GSE4290, and GSE138794) were included in this study. The intersection genes were obtained by overlapping differentially expressed genes (DEGs) from differential expression analysis in GSE16011, key module genes from WGCNA, and MRGs. Subsequently, the intersection genes were further screened to obtain prognostic genes. Following this, a risk model was developed and verified. After that, independent prognostic factors were identified, followed by the construction of a nomogram and subsequent evaluation of its predictive ability. Furthermore, immune microenvironment analysis and expression validation were implemented. The GSE138794 dataset was utilized to evaluate the expression of prognostic genes at a cellular level, followed by conducting an analysis on cell-to-cell communication. Finally, the results were validated in different datasets and tissue samples from patients.

RESULTS

ECI2, MCCC2, OXCT1, SUCLG2, and CPT2 were identified as prognostic genes for glioma. The risk model constructed based on these genes in TCGA-GBMLGG demonstrated certain accuracy in predicting the occurrence of glioma. Additionally, the nomogram constructed based on risk score and grade exhibited strong performance in predicting patient survival. Significant differences were observed in the proportion of 27 immune cell types (e.g., activated B cells and macrophages) and the expression of 32 immune checkpoints (e.g., CD70, CD200, and CD48) between the two risk groups. Single-cell RNA sequencing showed that CPT2, ECI2, and SUCLG2 were highly expressed in oligodendrocytes, neural progenitor cells, and BMDMs, respectively. The results of cell-cell communication analysis revealed that both oligodendrocytes and BMDMs exhibited a substantial number of interactions with high strength.

CONCLUSION

This study revealed five genes associated with the prognosis of glioma (ECI2, MCCC2, OXCT1, SUCLG2, and CPT2), providing novel insights into individualized treatment and prognosis.

Tissue-Resident Macrophages in Cancer: Friend or Foe?

INTRODUCTION

Macrophages are essential in maintaining homeostasis, combating infections, and influencing the process of various diseases, including cancer. Macrophages originate from diverse lineages: Notably, tissue-resident macrophages (TRMs) differ from hematopoietic stem cells and circulating monocyte-derived macrophages based on genetics, development, and function. Therefore, understanding the recruited and TRM populations is crucial for investigating disease processes.

METHODS

By searching literature databses, we summarized recent relevant studies. Research has shown that tumor-associated macrophages (TAMs) of distinct origins accumulate in tumor microenvironment (TME), with TRM-derived TAMs closely resembling gene signatures of normal TRMs.

RESULTS

Recent studies have revealed that TRMs play a crucial role in cancer progression. However, organ-specific effects complicate TRM investigations. Nonetheless, the precise involvement of TRMs in tumors is unclear. This review explores the multifaceted roles of TRMs in cancer, presenting insights into their origins, proliferation, the latest research methodologies, their impact across various tumor sites, their potential and strategies as therapeutic targets, interactions with other cells within the TME, and the internal heterogeneity of TRMs.

CONCLUSIONS

We believe that a comprehensive understanding of the multifaceted roles of TRMs will pave the way for targeted TRM therapies in the treatment of cancer.

In situ formed reactive oxygen species-responsive dipyridamole prodrug hydrogel: Spatiotemporal drug delivery for chemoimmunotherapy

In the realm of combined cancer immunotherapy, the strategic combination of therapeutics targeting both cancer cells and macrophages holds immense potential. However, the major challenges remain on how to achieve facile spatiotemporal delivery of these therapies, allowing ease of manipulation and ensuring differential drug release for enhanced synergistic therapeutic effects. In the present study, we introduced a tumor microenvironment (TME)-adapted hydrogel with the phenylboronic acid-modified dipyridamole prodrug (DIPP) as a crosslinker. This prodrug hydrogel scaffold, 3BP@DIPPGel, could be formed in situ by a simple mixture of DIPP and poly(vinyl alcohol) (PVA), and loaded with a high ratio of 3-bromopyruvic acid (3BP). The 3BP@DIPPGel enables spatiotemporal localized delivery of dipyridamole (DIP) and 3BP with distinct release kinetics that effectively reshape the immunosuppressive TME. Upon reactive oxygen species (ROS) stimulation, 3BP@DIPPGel preferentially released 3BP, inducing tumor-specific pyroptosis via the ROS/BAX/caspase-3/GSDME signaling pathway and decreasing the secretion of chemokines such as CCL8 to counteract macrophage recruitment. Subsequently, the crosslinked DIP is released, triggering the tumor-associated macrophages (TAMs) polarization towards the immunostimulatory M1 phenotype via the CCR2/JAK2/STAT3 cascade signaling pathway. This dual action from 3BP@DIPPGel leads to the restoration of tumor cell immunogenicity with high efficacy and activation of immune cells. Furthermore, the 3BP@DIPPGel-based chemoimmunotherapy upregulates the expression of sialic-acid-binding Ig-like lectin 10 and hence sensitizing tumors to anti-CD24 therapy in the tumor-bearing mice. Therefore, this strategy can have significant potential in the prevention of tumor metastases and recurrence. To the best of our understanding, this study represents a pioneering showcase of tumor pyroptosis, induced by glycolytic inhibitors, which can be effectively coordinated with DIP-mediated TAM polarization for immune activation, offering a new paradigm for differentially sustained drug delivery to foster cancer immunotherapy.

Spatial transcriptomics in pancreatic cancer: Advances, prospects and challenges

Pancreatic cancer remains one of the deadliest malignancies with an overall 5-year survival rate of 13 %. This dismal fact can be partly attributed to currently limited understanding of tumor heterogeneity and immune microenvironment. Traditional bulk-sequencing techniques overlook the diversity of tumor cells, while single-cell sequencing disorganizes the position localizing of cells in tumor microenvironment. The advent of spatial transcriptomics (ST) presents a novel solution by integrating location and whole transcript expression information. This technology allows for detailed observation of spatio-temporal changes across various cell subtypes within the pancreatic tumor microenvironment, providing insights into their potential functions. This review offers an overview of recent studies implementing ST in pancreatic cancer research, highlighting its instrumental role in investigating the heterogeneity and functions of tumor cells, stromal cells, and immune cells. On the basis, we also prospected and summarized the clinical application scenarios, technical limitations and challenges of ST technology in pancreatic cancer.

Application of Carbon Nanomaterials to Enhancing Tumor Immunotherapy: Current Advances and Prospects

Recent advances in tumor immunotherapy have highlighted the pivotal role of carbon nanomaterials, such as carbon dots, graphene quantum dots, and carbon nanotubes. This review examines the unique benefits of these materials in cancer treatment, focusing on their mechanisms of action within immunotherapy. These include applications in immunoregulation, recognition, and enhancement. We explore how these nanomaterials when combined with specific biomolecules, can form immunosensors. These sensors are engineered for highly sensitive and specific detection of tumor markers, offering crucial support for early diagnosis and timely therapeutic interventions. This review also addresses significant challenges facing carbon nanomaterials in clinical settings, such as issues related to long-term biocompatibility and the hurdles of clinical translation. These challenges require extensive ongoing research and discussion. This review is of both theoretical and practical importance, aiming to promote using carbon nanomaterials in tumor immunotherapy, potentially transforming clinical outcomes and enhancing patient care.

Engineering macrophage membrane-camouflaged nanoplatforms with enhanced macrophage function for mediating sonodynamic therapy of ovarian cancer

Cancer immunotherapy has demonstrated remarkable efficacy in the treatment of cancer, and it has been successfully applied in the treatment of various solid tumors. However, the response rates to immunotherapy in patients with ovarian cancer remain modest because of the immunosuppressive tumor microenvironment (TME). Tumor-associated macrophages (TAMs) represent the predominant myeloid cell population within the TME, which adopt the protumorigenic M2 phenotype and are blinded by the "don't eat me" signals from tumor cells. These characteristics of TAMs result in insufficient phagocytic activation. In this study, we constructed a SIM@TR-NP-mediated combination therapy of sonodynamic and immunotherapy. SIM@TR-NPs were modified by engineered macrophage membranes with overexpressed sialic acid-binding Ig-like lectin 10 (Siglec-10), and were internally loaded with sonosensitizer 4,4',4'',4'''-(porphine-5,10,15,20-tetrayl)tetrakis(benzoic acid) and immune adjuvant resiquimod. SIM@TR-NPs can block "don't eat me" signals to enhance macrophage phagocytosis and trigger the polarization of TAMs toward the M1 phenotype, thereby improving the immunosuppressive TME. Simultaneously, upon ultrasound irradiation, SIM@TR-NP-mediated sonodynamic therapy (SDT) triggered immunogenic cell death in tumor cells, in combination with TAM-based immunotherapy, transforming the "immune cold tumor" into an "immune hot tumor". SIM@TR-NP-mediated sonodynamic immunotherapy exhibited potent antitumor efficacy in ovarian cancer and exhibited substantial potential for improving the immunosuppressive TME. This study presents an emerging therapeutic regimen for ovarian cancer that synergizes TAM-based antitumor immunotherapy and SDT.

A novel hollow iron nanoparticle system loading PEG-Fe3O4 with C5a receptor antagonist for breast cancer treatment

Breast cancer is the most diagnosed malignancy and major cause of cancer death among women population in the worldwide. Ferroptosis is a recently discovered iron-dependent regulated cell death involved in tumor progression and therapeutic response. Moreover, increasing studies have implied that ferroptosis is a promising approach to eliminating cancer cells like developing iron nanoparticles as a therapeutic agent. However, resistance to ferroptosis is a vital distinctive hallmark of cancer. Therefore, further investigation of the mechanism of ferroptosis resistance to enhance its tumor sensitivity is essential for ferroptosis-target breast cancer therapy. Our results revealed that the activation of C5a/C5aR pathway can drive resistance to ferroptosis and reshaping breast cancer immune microenvironment. Accordingly, loading PEG-Fe3O4 with C5aRA significantly improved the anti-tumor effect of PEG- Fe3O4 by inhibiting ferroptosis resistance and increasing macrophage polarization toward M1 phenotype. Our findings presented a novel cancer therapy strategy that combined cancer cell metal metabolism regulation and immunotherapy. The study also provided support for further evaluation of PEG- Fe3O4@C5aRA as a novel therapeutic strategy for breast cancer in clinical trials.

The Immune Microenvironment in Prostate Cancer: A Comprehensive Review

BACKGROUND

Prostate cancer (PCa) is a malignancy with significant immunosuppressive properties and limited immune activation. This immunosuppression is linked to reduced cytotoxic T cell activity, impaired antigen presentation, and elevated levels of immunosuppressive cytokines and immune checkpoint molecules. Studies demonstrate that cytotoxic CD8+ T cell infiltration correlates with improved survival, while increased regulatory T cells (Tregs) and tumor-associated macrophages (TAMs) are associated with worse outcomes and therapeutic resistance. Th1 cells are beneficial, whereas Th17 cells, producing interleukin-17 (IL-17), contribute to tumor progression. Tumor-associated neutrophils (TANs) and immune checkpoint molecules, such as PD-1/PD-L1 and T cell immunoglobulin-3 (TIM-3) are also linked to advanced stages of PCa. Chemotherapy holds promise in converting the "cold" tumor microenvironment (TME) to a "hot" one by depleting immunosuppressive cells and enhancing tumor immunogenicity.

SUMMARY

This comprehensive review examines the immune microenvironment in PCa, focusing on the intricate interactions between immune and tumor cells in the TME. It highlights how TAMs, Tregs, cytotoxic T cells, and other immune cell types contribute to tumor progression or suppression and how PCa's low immunogenicity complicates immunotherapy.

KEY MESSAGES

The infiltration of cytotoxic CD8+ T cells and Th1 cells correlates with better outcomes, while elevated T regs and TAMs promote tumor growth, metastasis, and resistance. TANs and natural killer (NK) cells exhibit dual roles, with higher NK cell levels linked to better prognoses. Immune checkpoint molecules like PD-1, PD-L1, and TIM-3 are associated with advanced disease. Chemotherapy can improve tumor immunogenicity by depleting T regs and myeloid-derived suppressor cells, offering therapeutic promise.

CAR-macrophage: Breaking new ground in cellular immunotherapy

Chimeric Antigen Receptor (CAR) technology has revolutionized cellular immunotherapy, particularly with the success of CAR-T cells in treating hematologic malignancies. However, CAR-T cells have the limited efficacy of against solid tumors. To address these limitations, CAR-macrophages (CAR-Ms) leverage the innate properties of macrophages with the specificity and potency of CAR technology, offering a novel and promising approach to cancer immunotherapy. Preclinical studies have shown that CAR-Ms can effectively target and destroy tumor cells, even within challenging microenvironments, by exhibiting direct cytotoxicity and enhancing the recruitment and activation of other immune cells. Additionally, the favorable safety profile of macrophages and their persistence within solid tumors position CAR-Ms as potentially safer and more durable therapeutic options compared to CAR-T cells. This review explores recent advancements in CAR-Ms technology, including engineering strategies to optimize their anti-tumor efficacy and preclinical evidence supporting their use. We also discuss the challenges and future directions in developing CAR-Ms therapies, emphasizing their potential to revolutionize cellular immunotherapy. By harnessing the unique properties of macrophages, CAR-Ms offer a groundbreaking approach to overcoming the current limitations of CAR-T cell therapies, paving the way for more effective and sustainable cancer treatments.

Understanding Macrophage-Tumor Interactions: Insights from Single-Cell Behavior Monitoring in a Sessile Microdroplet System

Interaction between tumor-associated macrophages and tumor cells is crucial for tumor development, metastasis, and the related immune process. However, the macrophages are highly heterogeneous spanning from anti-tumorigenic to pro-tumorigenic, which needs to be understood at the single-cell level. Herein, a sessile microdroplet system designed for monitoring cellular behavior and analyzing intercellular interaction, demonstrated with macrophage-tumor cell pairs is presented. An automatic procedure based on the inkjet printing method is utilized for the precise pairing and co-encapsulation of heterotypic cells within picoliter droplets. The sessile nature of microdroplets ensures controlled fusion and provides stable environments conducive to adherent cell culture. The nitric oxide generation and morphological changes over incubation are explored to reveal the complicated interactions from a single-cell perspective. The immune response of macrophages under distinct cellular microenvironments is recorded. The results demonstrate that the tumor microenvironment displays a modulating role in polarizing macrophages from anti-tumorigenic into pro-tumorigenic phenotype. The approach provides a versatile and compatible platform to investigate intercellular interaction at the single-cell level, showing promising potential for advancing single-cell behavior studies.

PLXDC1 serves as a potential prognostic marker and involves in malignant progression and macrophage polarization in colon cancer

The malignant behavior and immune escape ability of cancer cells lead to therapeutic failure and poor prognosis for patients with various cancers, including colon cancer. Plexin domain containing 1 (PLXDC1) was initially identified to exert key roles in tumor by regulating angiogenesis and has recently proved to be involved in cell proliferation and migration of glioblastoma and gastric cancer cells. However, its roles in colon cancer remain unclear. In this study, the online bioinformatics databases confirmed high expression of PLXDC1 in colon cancer specimens, which was associated with cancer stages and nodal metastasis. Similarly, the increased expression of PLXDC1 was also validated in our collected samples and colon cancer cells. Moreover, patients with high expression of PLXDC1 had shorter survival, indicating that PLXDC1 might be a potential prognostic predictor for colon cancer patients. Notably, targeting PLXDC1 inhibited cancer cell viability and invasion, and enhanced cell apoptosis. Intriguingly, Tumor Immune Estimation Resource database confirmed that PLXDC1 expression was related to various tumor-infiltrating immune cells in colon adenocarcinoma including macrophages, and its expression was also correlated with M2-like macrophage markers. In vitro, colon cancer cells with PLXDC1 downregulation had a reduced ability to recruit and polarize macrophage towards M2 phenotype by decreasing the percentage of CD206+ cells and M2-like markers (CD206, CD163, arginase1, and interleukin 10 [IL-10]). Moreover, PLXDC1 knockdown attenuated M2 macrophage-mediated promotion in cancer cell viability and invasion. Mechanically, inhibition of PLXDC1 suppressed activation of the IL-6/Signal transducer and activator of transcription 3 (STAT3) signaling. Reactivating the above pathway by transfection with IL-6 plasmids reversed the suppressive effects of PLXDC1 knockdown on cancer cell malignant behaviors, macrophage recruitment and M2-like polarization. Thus, PLXDC1 downregulation may inhibit the malignancy of colon cancer cells and their ability to recruit and polarize macrophages towards M2 phenotype by blocking the IL-6/STAT3 pathway. Together, targeting PLXDC1 may attenuate the progression of colon cancer by direct roles in cancer cells and indirect roles in macrophage polarization, representing a promising therapeutic target for colon cancer patients.

Tumor-associated macrophages: A sentinel of innate immune system in tumor microenvironment gone haywire

The tumor microenvironment (TME) is a critical determinant in the initiation, progression, and treatment outcomes of various cancers. Comprising of cancer-associated fibroblasts (CAF), immune cells, blood vessels, and signaling molecules, the TME is often likened to the soil supporting the seed (tumor). Among its constituents, tumor-associated macrophages (TAMs) play a pivotal role, exhibiting a dual nature as both promoters and inhibitors of tumor growth. This review explores the intricate relationship between TAMs and the TME, emphasizing their diverse functions, from phagocytosis and tissue repair to modulating immune responses. The plasticity of TAMs is highlighted, showcasing their ability to adopt either protumorigenic or anti-tumorigenic phenotypes based on environmental cues. In the context of cancer, TAMs' pro-tumorigenic activities include promoting angiogenesis, inhibiting immune responses, and fostering metastasis. The manuscript delves into therapeutic strategies targeting TAMs, emphasizing the challenges faced in depleting or inhibiting TAMs due to their multifaceted roles. The focus shifts towards reprogramming TAMs to an anti-tumorigenic M1-like phenotype, exploring interventions such as interferons, immune checkpoint inhibitors, and small molecule modulators. Noteworthy advancements include the use of CSF1R inhibitors, CD40 agonists, and CD47 blockade, demonstrating promising results in preclinical and clinical settings. A significant section is dedicated to Chimeric Antigen Receptor (CAR) technology in macrophages (CAR-M cells). While CAR-T cells have shown success in hematological malignancies, their efficacy in solid tumors has been limited. CAR-M cells, engineered to infiltrate solid tumors, are presented as a potential breakthrough, with a focus on their development, challenges, and promising outcomes. The manuscript concludes with the exploration of third-generation CAR-M technology, offering insight into in-vivo reprogramming and nonviral vector approaches. In conclusion, understanding the complex and dynamic role of TAMs in cancer is crucial for developing effective therapeutic strategies. While early-stage TAM-targeted therapies show promise, further extensive research and larger clinical trials are warranted to optimize their targeting and improve overall cancer treatment outcomes.

Harnessing cells to improve transport of nanomedicines

Efficient tumour treatment is hampered by the poor selectivity of anticancer drugs, resulting in scarce tumour accumulation and undesired off-target effects. Nano-sized drug-delivery systems in the form of nanoparticles (NPs) have been proposed to improve drug distribution to solid tumours, by virtue of their ability of passive and active tumour targeting. Despite these advantages, literature studies indicated that less than 1% of the administered NPs can successfully reach the tumour mass, highlighting the necessity for more efficient drug transporters in cancer treatment. Living cells, such as blood cells, circulating immune cells, platelets, and stem cells, are often found as an infiltrating component in most solid tumours, because of their ability to naturally circumvent immune recognition, bypass biological barriers, and reach inaccessible tissues through innate tropism and active motility. Therefore, the tumour-homing ability of these cells can be harnessed to design living cell carriers able to improve the transport of drugs and NPs to tumours. Albeit promising, this approach is still in its beginnings and suffers from difficult scalability, high cost, and poor reproducibility. In this review, we present an overview of the most common cell transporters of drugs and NPs, and we discuss how different cell types interact with biological barriers to deliver cargoes of various natures to tumours. Finally, we analyse the different techniques used to load drugs or NPs in living cells and discuss their advantages and disadvantages.

Tumor‑associated macrophages activated in the tumor environment of hepatocellular carcinoma: Characterization and treatment (Review)

Hepatocellular carcinoma (HCC) tissue is rich in dendritic cells, T cells, B cells, macrophages, natural killer cells and cellular stroma. Together they form the tumor microenvironment (TME), which is also rich in numerous cytokines. Tumor‑associated macrophages (TAMs) are involved in the regulation of tumor development. TAMs in HCC receive stimuli in different directions, polarize in different directions and release different cytokines to regulate the development of HCC. TAMs are mostly divided into two cell phenotypes: M1 and M2. M1 TAMs secrete pro‑inflammatory mediators, and M2 TAMs secrete a variety of anti‑inflammatory and pro‑tumorigenic substances. The TAM polarization in HCC tumors is M2. Both direct and indirect methods for TAMs to regulate the development of HCC are discussed. TAMs indirectly support HCC development by promoting peripheral angiogenesis and regulating the immune microenvironment of the TME. In terms of the direct regulation between TAMs and HCC cells, the present review mainly focuses on the molecular mechanism. TAMs are involved in both the proliferation and apoptosis of HCC cells to regulate the quantitative changes of HCC, and stimulate the related invasive migratory ability and cell stemness of HCC cells. The present review aims to identify immunotherapeutic options based on the mechanisms of TAMs in the TME of HCC.

The MCIB Model: A Novel Theory for Describing the Spatial Heterogeneity of the Tumor Microenvironment

The tumor microenvironment (TME) can be regarded as a complex and dynamic microecosystem generated by the interactions of tumor cells, interstitial cells, the extracellular matrix, and their products and plays an important role in the occurrence, progression and metastasis of tumors. In a previous study, we constructed an IEO model (prI-, prE-, and pOst-metastatic niche) according to the chronological sequence of TME development. In this paper, to fill the theoretical gap in spatial heterogeneity in the TME, we defined an MCIB model (Metabolic, Circulatory, Immune, and microBial microenvironment). The MCIB model divides the TME into four subtypes that interact with each other in terms of mechanism, corresponding to the four major links of metabolic reprogramming, vascular remodeling, immune response, and microbial action, providing a new way to assess the TME. The combination of the MCIB model and IEO model comprehensively depicts the spatiotemporal evolution of the TME and can provide a theoretical basis for the combination of clinical targeted therapy, immunotherapy, and other comprehensive treatment modalities for tumors according to the combination and crosstalk of different subtypes in the MCIB model and provide a powerful research paradigm for tumor drug-resistance mechanisms and tumor biological behavior.

Pre-metastatic niche: formation, characteristics and therapeutic implication

Distant metastasis is a primary cause of mortality and contributes to poor surgical outcomes in cancer patients. Before the development of organ-specific metastasis, the formation of a pre-metastatic niche is pivotal in promoting the spread of cancer cells. This review delves into the intricate landscape of the pre-metastatic niche, focusing on the roles of tumor-derived secreted factors, extracellular vesicles, and circulating tumor cells in shaping the metastatic niche. The discussion encompasses cellular elements such as macrophages, neutrophils, bone marrow-derived suppressive cells, and T/B cells, in addition to molecular factors like secreted substances from tumors and extracellular vesicles, within the framework of pre-metastatic niche formation. Insights into the temporal mechanisms of pre-metastatic niche formation such as epithelial-mesenchymal transition, immunosuppression, extracellular matrix remodeling, metabolic reprogramming, vascular permeability and angiogenesis are provided. Furthermore, the landscape of pre-metastatic niche in different metastatic organs like lymph nodes, lungs, liver, brain, and bones is elucidated. Therapeutic approaches targeting the cellular and molecular components of pre-metastatic niche, as well as interventions targeting signaling pathways such as the TGF-β, VEGF, and MET pathways, are highlighted. This review aims to enhance our understanding of pre-metastatic niche dynamics and provide insights for developing effective therapeutic strategies to combat tumor metastasis.

Nanozymes in cancer immunotherapy: metabolic disruption and therapeutic synergy

Over the past decade, there has been a growing emphasis on investigating the role of immunotherapy in cancer treatment. However, it faces challenges such as limited efficacy, a diminished response rate, and serious adverse effects. Nanozymes, a subset of nanomaterials, demonstrate boundless potential in cancer catalytic therapy for their tunable activity, enhanced stability, and cost-effectiveness. By selectively targeting the metabolic vulnerabilities of tumors, they can effectively intensify the destruction of tumor cells and promote the release of antigenic substances, thereby eliciting immune clearance responses and impeding tumor progression. Combined with other therapies, they synergistically enhance the efficacy of immunotherapy. Hence, a large number of metabolism-regulating nanozymes with synergistic immunotherapeutic effects have been developed. This review summarizes recent advancements in cancer immunotherapy facilitated by nanozymes, focusing on engineering nanozymes to potentiate antitumor immune responses by disturbing tumor metabolism and performing synergistic treatment. The challenges and prospects in this field are outlined. We aim to provide guidance for nanozyme-mediated immunotherapy and pave the way for achieving durable tumor eradication.

Polarization of Macrophages in Tumor Microenvironment Using High-Throughput Single-Cell Metabolomics

Macrophages consist of a heterogeneous population of functionally distinct cells that participate in many physiological and pathological processes. They exhibit prominent plasticity by changing their different functional phenotypes represented by proinflammatory (M1) and anti-inflammatory (M2) in response to different environmental stimuli. Emerging evidence illustrates the importance of intracellular metabolic pathways in macrophage polarizations and functions. In the tumor microenvironment (TME), macrophages tend to M2 polarization, which promotes tumor growth and leads to adverse physiological effects. Due to the lack of highly specific antigens in M1 and M2 macrophages, significant challenges present in isolating these subtypes from clinical samples or in vitro coculture models of tumor-immune cells. In reverse, the single-cell technique provides the possibility to investigate the factors influencing macrophage polarization in the TME. In this research, we employed inertial microfluidic chip-mass spectrometry (IMC-MS) to conduct single-cell metabolomics analysis of macrophages polarized into the two major phenotypes, respectively, and 213 metabolites were identified in total. Subsequently, differential metabolites between macrophage phenotypes were analyzed using volcano plots and binary logistic regression models. Glutamine was pinpointed as a key metabolite for the M1 and M2 phenotypes. Experimental results from both monoculture and coculture cell models demonstrated that M1 polarization is more reliant on the presence of glutamine in the culture environment than M2 polarization. Glutamine deficiency resulted in failed M1 polarization, while its absence had a less pronounced effect on M2 polarization. Replenishing an appropriate amount of glutamine during the intermediate stages of coculture models significantly enhanced the proportion of M1 polarization and suppressed the growth of tumor cells. This research elucidated glutamine as a key factor influencing macrophage polarization in the TME via single-cell metabolomics based on IMC-MS, offering promising insights and targets for tumor therapies.

Natural plant-derived polysaccharides targeting macrophage polarization: a promising strategy for cancer immunotherapy

Tumor associated macrophages (TAMs) are the predominant innate immune cells in the tumor microenvironment (TME). Cytokines induce the differentiation of macrophages into distinct types of TAMs, primarily characterized by two phenotypes: M1-polarized and M2-polarized. Cancer growth is suppressed by M1-polarized macrophages and promoted by M2-polarized macrophages. The regulation of macrophage M1 polarization has emerged as a promising strategy for cancer immunotherapy. Polysaccharides are important bioactive substances found in numerous plants, manifesting a wide range of noteworthy biological actions, such as immunomodulation, anti-tumor effects, antioxidant capabilities, and antiviral functions. In recent years, there has been a significant increase in interest regarding the immunomodulatory and anti-tumor properties of polysaccharides derived from plants. The regulatory impact of polysaccharides on the immune system is mainly associated with the natural immune response, especially with the regulation of macrophages. This review provides a thorough analysis of the regulatory effects and mechanisms of plant polysaccharides on TAMs. Additionally, an analysis of potential opportunities for clinical translation of plant polysaccharides as immune adjuvants is presented. These insights have greatly advanced the research of plant polysaccharides for immunotherapy in tumor-related applications.

Cell therapy using ex vivo reprogrammed macrophages enhances antitumor immune responses in melanoma

BACKGROUND

Macrophage-based cell therapies have shown modest success in clinical trials, which can be attributed to their phenotypic plasticity, where transplanted macrophages get reprogrammed towards a pro-tumor phenotype. In most tumor types, including melanoma, the balance between antitumor M1-like and tumor-promoting M2-like macrophages is critical in defining the local immune response with a higher M1/M2 ratio favoring antitumor immunity. Therefore, designing novel strategies to increase the M1/M2 ratio in the TME has high clinical significance and benefits macrophage-based cell therapies.

METHODS

In this study, we reprogrammed antitumor and proinflammatory macrophages ex-vivo with HDAC6 inhibitors (HDAC6i). We administered the reprogrammed macrophages intratumorally as an adoptive cell therapy (ACT) in the syngeneic SM1 murine melanoma model and patient-derived xenograft bearing NSG-SGM3 humanized mouse models. We phenotyped the tumor-infiltrated immune cells by flow cytometry and histological analysis of tumor sections for macrophage markers. We performed bulk RNA-seq profiling of murine bone marrow-derived macrophages treated with vehicle or HDAC6i and single-cell RNA-seq profiling of SM1 tumor-infiltrated immune cells to determine the effect of intratumor macrophage ACT on the tumor microenvironment (TME). We further analyzed the single-cell data to identify key cell-cell interactions and trajectory analysis to determine the fate of tumor-associated macrophages post-ACT.

RESULTS

Macrophage ACT resulted in diminished tumor growth in both mouse models. We also demonstrated that HDAC6 inhibition in macrophages suppressed the polarization toward tumor-promoting phenotype by attenuating STAT3-mediated M2 reprogramming. Two weeks post-transplantation, ACT macrophages were viable, and inhibition of HDAC6 rendered intratumor transplanted M1 macrophages resistant to repolarization towards protumor M2 phenotype in-vivo. Further characterization of tumors by flow cytometry, single-cell transcriptomics, and single-cell secretome analyses revealed a significant enrichment of antitumor M1-like macrophages, resulting in increased M1/M2 ratio and infiltration of CD8 effector T-cells. Computational analysis of single-cell RNA-seq data for cell-cell interactions and trajectory analyses indicated activation of monocytes and T-cells in the TME.

CONCLUSIONS

In summary, for the first time, we demonstrated the potential of reprogramming macrophages ex-vivo with HDAC6 inhibitors as a viable macrophage cell therapy to treat solid tumors.

Organelle Specific Macrophage Engineered Vesicles Differentially Reprogram Macrophage Polarization

Tumor-associated macrophages (TAMs) represent the majority of the immune cells present in the tumor microenvironment. These macrophages exhibit an anti-inflammatory (M2)-like physiological state and execute immune-suppressive and tumor-supporting properties. With TAMs being plastic, there is a growing interest in reprogramming them toward a pro-inflammatory (M1)-like phenotype that exhibits anti-tumoral properties. Recent studies have demonstrated that both engineered vesicles derived from macrophages and endogenous extracellular vesicles produced by macrophages can be programmed to alter macrophage phenotype. Here it is demonstrated that pro-inflammatory macrophage-engineered subcellular vesicles (MEVs) have differential properties based on their organelle of origin. Endoplasmic reticulum specific MEVs (erMEVs) treated M2 macrophages exhibit enhanced pro-inflammatory cytokine production compared to plasma membrane specific MEVs (pmMEVs) treated M2 macrophages. In addition, under in vitro co-culture conditions, erMEVs elicit superior efficacy in suppressing the viability of cancer cells compared to the same concentration of pmMEVs. Furthermore, erMEVs and pmMEVs maintain differences in their membrane proteins, that regulate the repolarization efficacy of M2 macrophages toward an M1-like phenotype. In addition, The M2 to M1 repolarizing efficacy of MEVs can be altered by changing the activity of the membrane proteins present on erMEVs or pmMEVs.

SHISA3 Reprograms Tumor-Associated Macrophages Toward an Antitumoral Phenotype and Enhances Cancer Immunotherapy

The main challenge for immune checkpoint blockade (ICB) therapy lies in immunosuppressive tumor microenvironment (TME). Repolarizing M2-like tumor-associated macrophages (TAMs) into inflammatory M1 phenotype is a promising strategy for cancer immunotherapy. Here, this study shows that the tumor suppressive protein SHISA3 regulates the antitumor functions of TAMs. Local delivery of mRNA encoding Shisa3 enables cancer immunotherapy by reprogramming TAMs toward an antitumoral phenotype, thus enhancing the efficacy of programmed cell death 1 (PD-1) antibody. Enforced expression of Shisa3 in TAMs increases their phagocytosis and antigen presentation abilities and promotes CD8+ T cell-mediated antitumor immunity. The expression of SHISA3 is induced by damage/pathogen-associated molecular patterns (DAMPs/PAMPs) in macrophages via nuclear factor-κB (NF-κB) transcription factors. Reciprocally, SHISA3 forms a complex with heat shock protein family A member 8 (HSPA8) to activate NF-κB signaling thus maintaining M1 polarization of macrophages. Knockout Shisa3 largely abolishes the antitumor efficacy of combination immunotherapy with Toll-like receptor 4 (TLR4) agonist monophosphoryl lipid A (MPLA) and PD-1 antibody. It further found that higher expression of SHISA3 in antitumoral TAMs is associated with better overall survival in lung cancer patients. Taken together, the findings describe the role of SHISA3 in reprogramming TAMs that ameliorate cancer immunotherapy.

Chinese Medicines and Natural Medicine as Immunotherapeutic Agents for Gastric Cancer: Recent Advances

BACKGROUD

According to the 2020 statistics from the World Health Organization's International Agency for Research on Cancer (IARC), it is projected that there will be over 1 million new cases of gastric cancer (GC) patients worldwide in 2020, resulting in approximately 770 000 deaths. Gastric cancer ranks fifth in terms of incidence rate and forth in death rate among malignant tumors. Despite advancements in early diagnostic techniques, the incidence of GC has exhibited a marginal decline; nevertheless, the mortality rate remains elevated for advanced inoperable patients with no currently available efficacious treatment options.

RECENT FINDING

Chinese medicine (CM) has emerged as an efficacious treatment for GC, gradually gaining acceptance and widespread usage in China. It exhibits distinctive advantages in the prevention and treatment of metastasis. CM and natural medicine possess the ability to elicit antitumor effects by augmenting immune cell population, enhancing immune cell activity, and improving the tumor immune microenvironment. CMs and natural remedies encompass a diverse range of types, characterized by multiple targets, pathways, and extensive pharmacological effects. Consequently, they have become a prominent research area among oncologists worldwide. Numerous studies have demonstrated that CM and natural medicine can directly or indirectly enhance innate immune system components (including macrophages, natural killer cells, and myeloid suppressor cells), adaptive immune system elements (such as T lymphocytes and regulatory T cells), relevant cytokines (e.g., IL-2, IL-4, IL-10, TNF-α), and PD-1/PD-L1 axis regulation, thereby bolstering the cytotoxicity of immune cells against tumor cells.

CONCLUSIONS

This ultimately leads to an improved tumor immune microenvironment facilitating superior antitumor efficacy. This paper critically examines the role of CM and natural medicine in regulating immunotherapy for GC, aiming to establish a new theoretical framework for the clinical treatment and prevention of gastric cancer within the realm of CM.

Immune Cell-Based Microrobots for Remote Magnetic Actuation, Antitumor Activity, and Medical Imaging

Translating medical microrobots into clinics requires tracking, localization, and performing assigned medical tasks at target locations, which can only happen when appropriate design, actuation mechanisms, and medical imaging systems are integrated into a single microrobot. Despite this, these parameters are not fully considered when designing macrophage-based microrobots. This study presents living macrophage-based microrobots that combine macrophages with magnetic Janus particles coated with FePt nanofilm for magnetic steering and medical imaging and bacterial lipopolysaccharides for stimulating macrophages in a tumor-killing state. The macrophage-based microrobots combine wireless magnetic actuation, tracking with medical imaging techniques, and antitumor abilities. These microrobots are imaged under magnetic resonance imaging and optoacoustic imaging in soft-tissue-mimicking phantoms and ex vivo conditions. Magnetic actuation and real-time imaging of microrobots are demonstrated under static and physiologically relevant flow conditions using optoacoustic imaging. Further, macrophage-based microrobots are magnetically steered toward urinary bladder tumor spheroids and imaged with a handheld optoacoustic device, where the microrobots significantly reduce the viability of tumor spheroids. The proposed approach demonstrates the proof-of-concept feasibility of integrating macrophage-based microrobots into clinic imaging modalities for cancer targeting and intervention, and can also be implemented for various other medical applications.

Macrophages and tertiary lymphoid structures as indicators of prognosis and therapeutic response in cancer patients

Tertiary lymphoid structures (TLS) can reflect cancer prognosis and clinical outcomes in various tumour tissues. Tumour-associated macrophages (TAMs) are indispensable components of the tumour microenvironment and play crucial roles in tumour development and immunotherapy. TAMs are associated with TLS induction via the modulation of the T cell response, which is a major component of the TLS. Despite their important roles in cancer immunology, the subtypes of TAMs that influence TLS and their correlation with prognosis are not completely understood. Here, we provide novel insights into the role of TAMs in regulating TLS formation. Furthermore, we discuss the prognostic value of these TAM subtypes and TLS, as well as the current antitumour therapies for inducing TLS. This study highlights an entirely new field of TLS regulation that may lead to the development of an innovative perspective on immunotherapy for cancer treatment.

Dissection of pro-tumoral macrophage subtypes and immunosuppressive cells participating in M2 polarization

Alternatively activated macrophage (M2) polarization can result in one of four subtypes based on cytokines and signaling pathways associated with macrophage activation: M2a, M2b, M2c, and M2d macrophages. The majority of M2 subtypes are anti-inflammatory and pro-angiogenic, secreting growth factors (VEGF, PDGF) and matrix metalloproteinases (MMP2, MMP9) which boost tumor growth, metastasis, and invasion. M2-polarized macrophages are associated with immune suppressor cells harboring Myeloid derived suppressor cells, Regulatory T cells (Tregs), Regulatory B cells as well as alternatively activated (N2) neutrophils. Treg cells selectively support the metabolic stability, mitochondrial integrity, and survival rate of M2-like TAMs in an indirect environment. Also, the contribution of Breg cells influences macrophage polarization towards the M2 direction. TAM is activated when TAN levels in the tumor microenvironment are insufficient or vice versa, suggesting that macrophage and its polarization are fine-tuned. Understanding the functions of immune suppressive cells, mediators, and signaling pathways involved with M2 polarization will allow us to identify potential strategies for targeting the TAM repolarization phenotype for innovative immunotherapy approaches. In this review, we have highlighted the critical factors for M2 macrophage polarization, differential cytokine/chemokine profiles of M1 and M2 macrophage subtypes, and other immune cells' impact on the polarization within the immunosuppressive niche.

The menace of severe adverse events and deaths associated with viral gene therapy and its potential solution

Over the past decade, in vivo gene replacement therapy has significantly advanced, resulting in market approval of numerous therapeutics predominantly relying on adeno-associated viral vectors (AAV). While viral vectors have undeniably addressed several critical healthcare challenges, their clinical application has unveiled a range of limitations and safety concerns. This review highlights the emerging challenges in the field of gene therapy. At first, we discuss both the role of biological barriers in viral gene therapy with a focus on AAVs, and review current landscape of in vivo human gene therapy. We delineate advantages and disadvantages of AAVs as gene delivery vehicles, mostly from the safety perspective (hepatotoxicity, cardiotoxicity, neurotoxicity, inflammatory responses etc.), and outline the mechanisms of adverse events in response to AAV. Contribution of every aspect of AAV vectors (genomic structure, capsid proteins) and host responses to injected AAV is considered and substantiated by basic, translational and clinical studies. The updated evaluation of recent AAV clinical trials and current medical experience clearly shows the risks of AAVs that sometimes overshadow the hopes for curing a hereditary disease. At last, a set of established and new molecular and nanotechnology tools and approaches are provided as potential solutions for mitigating or eliminating side effects. The increasing number of severe adverse reactions and, sadly deaths, demands decisive actions to resolve the issue of immune responses and extremely high doses of viral vectors used for gene therapy. In response to these challenges, various strategies are under development, including approaches aimed at augmenting characteristics of viral vectors and others focused on creating secure and efficacious non-viral vectors. This comprehensive review offers an overarching perspective on the present state of gene therapy utilizing both viral and non-viral vectors.

Manipulating the tumour immune microenvironment by N6-methyladenosine RNA modification

N6-methyladenosine (m6A), a posttranscriptional regulatory mechanism, is the most common epigenetic modification in mammalian mRNA. M6A modifications play a crucial role in the developmental network of immune cells. The expression of m6A-related regulators often affects carcinogenesis and tumour suppression networks. In the tumour microenvironment, m6A-modified enzymes can affect the occurrence and progression of tumours by regulating the activation and invasion of tumour-associated immune cells. Immunotherapy, which utilises immune cells, has been demonstrated to be a powerful weapon in tumour treatment and is increasingly being used in the clinic. Here, we provide an updated and comprehensive overview of how m6A modifications affect invasive immune cells and their potential role in immune regulation. In addition, we summarise the regulation of epigenetic regulators associated with m6A modifications in tumour cells on the antitumour response of immune cells in the tumour immune microenvironment. These findings provide new insights into the role of m6A modifications in the immune response and tumour development, leading to the development of novel immunotherapies for cancer treatment.

Tumor micro-environment induced TRAIL secretion from engineered macrophages for anti-tumor therapy

The high plasticity and long-term persistency make macrophages excellent vehicles for delivering anti-tumor cytokines. Macrophage delivery of chemokines and cytokines shows potential in tumor therapy. TRAIL, a promising anti-tumor cytokine, induces apoptosis in tumor cells with low toxicity to normal cells. However, its off-target toxicity and limited stability have limited its clinical progress. Here, we engineered macrophages with Mono-TRAIL and Tri-TRAIL and found that Tri-TRAIL had higher cytotoxic activity against tumor cells than Mono-TRAIL in vitro. To target the tumor microenvironment (TME), we generated macrophages secreting trimeric TRAIL (Tri-TRAIL-iM) induced by the TME-specific promoter Arg1. The Tri-TRAIL-iM cells displayed high specific activatable activity in cell-based co-culture assay and tumor-baring mice models. In addition, we demonstrated that compared to macrophages over-expressing TRAIL under a non-inducible promoter, Tri-TRAIL-iM could more effectively induce apoptosis in cancer cells, inhibit tumor growth, and reduce systemic side effects. This strategy of inducing TRAIL delivery holds great potential for cancer therapy. It is promising to be combined with other engineering methods to maximize the therapeutic effects of solid tumors.

Potential applications of macrophages in cancer immunotherapy

Immunotherapy has improved cancer treatment based on investigations of tumor immune escape. Manipulation of the immune system stimulates antitumor immune responses and blocks tumor immune escape routes. Genetically adoptive cell therapy, such as T cells, has yielded promising results for hematologic malignancies, but their application to solid tumors has been challenging. Macrophages have a wide broad of capabilities in regulating immune responses, homeostasis, and tissue development, as well as the ability to phagocyte, present antigens, and infiltrate the tumor microenvironment (TME). Given the importance of macrophages in cancer development, they could serve as novel tool for tumor treatment. Therefore, macrophages are used in different formats for direct and indirect targeting of tumor cells. This review summarized the available data on the various applications of macrophages in cancer immunotherapy.

Modulating macrophage-mediated programmed cell removal: An attractive strategy for cancer therapy

Macrophage-mediated programmed cell removal (PrCR) is crucial for the identification and elimination of needless cells that maintain tissue homeostasis. The efficacy of PrCR depends on the balance between pro-phagocytic "eat me" signals and anti-phagocytic "don't eat me" signals. Recently, a growing number of studies have shown that tumourigenesis and progression are closely associated with PrCR. In the tumour microenvironment, PrCR activated by the "eat me" signal is counterbalanced by the "don't eat me" signal of CD47/SIRPα, resulting in tumour immune escape. Therefore, targeting exciting "eat me" signalling while simultaneously suppressing "don't eat me" signalling and eventually inducing macrophages to produce effective PrCR will be a very attractive antitumour strategy. Here, we comprehensively review the functions of PrCR-activating signal molecules (CRT, PS, Annexin1, SLAMF7) and PrCR-inhibiting signal molecules (CD47/SIRPα, MHC-I/LILRB1, CD24/Siglec-10, SLAMF3, SLAMF4, PD-1/PD-L1, CD31, GD2, VCAM1), the interactions between these molecules, and Warburg effect. In addition, we highlight the molecular regulatory mechanisms that affect immune system function by exciting or suppressing PrCR. Finally, we review the research advances in tumour therapy by activating PrCR and discuss the challenges and potential solutions to smooth the way for tumour treatment strategies that target PrCR.

Cigarette smoke-induced exosomal miR-221-3p facilitates M1 macrophage polarization via the STAT3 pathway in chronic obstructive pulmonary disease

AIMS

Chronic obstructive pulmonary disease (COPD) is marked by irreversible airflow limitations stemming from small airway constriction and lung emphysema. The advancement of COPD is greatly influenced by the M1 polarization of macrophages. The mechanisms governing macrophage polarization in inflammation conditions in COPD are not yet fully understood.

METHODS

To investigate the interplay between exosomes triggered by cigarette smoke and the polarization of macrophages, we utilized a combination of flow cytometry, quantitative real-time reverse transcription PCR, and western blot analysis.

RESULTS

Our research reveals that cigarette smoke (CS) exposure induces the secretion of exosomes from human bronchial epithelial cells, with exosomal miR-221-3p identified as a key player in modulating the polarization of M1 macrophages. The evidence indicates that cigarette smoke promotes exosome secretion in these cells, with exosomal miR-221-3p targeting SOCS3 and regulating the STAT3 signaling pathway to facilitate M1 macrophage polarization.

CONCLUSIONS

This research delves into the molecular pathways through which miR-221-3p facilitates the polarization of M1 macrophages, presenting a groundbreaking approach for potential targeted therapy in COPD.

The complex role of macrophages in pancreatic cancer tumor microenvironment: a review on cancer progression and potential therapeutic targets

Pancreatic cancer (PC) is one of the deadliest cancers worldwide with low survival rates and poor outcomes. The treatment landscape for PC is fraught with obstacles, including drug resistance, lack of effective targeted therapies and the immunosuppressive tumor microenvironment (TME). The resistance of PC to existing immunotherapies highlights the need for innovative approaches, with the TME emerging as a promising therapeutic target. The recent advancements in understanding the role of macrophages, this context highlight their significant impact on tumor development and progression. There are two important types of macrophages: M1 and M2, which play critical roles in the TME. Therapeutics strategies including, depletion of tumor-associated macrophages (TAMs), reprogramming TAMs to promote anti-tumor activity, and targeting macrophage recruitment can lead to promising outcomes. Targeting macrophage-related pathways may offer novel strategies for modulating immune responses, inhibiting angiogenesis, and overcoming resistance to chemotherapy in PC treatment.

Advancements in strategies for overcoming the blood-brain barrier to deliver brain-targeted drugs

The blood-brain barrier is known to consist of a variety of cells and complex inter-cellular junctions that protect the vulnerable brain from neurotoxic compounds; however, it also complicates the pharmacological treatment of central nervous system disorders as most drugs are unable to penetrate the blood-brain barrier on the basis of their own structural properties. This dramatically diminished the therapeutic effect of the drug and compromised its biosafety. In response, a number of drugs are often delivered to brain lesions in invasive ways that bypass the obstruction of the blood-brain barrier, such as subdural administration, intrathecal administration, and convection-enhanced delivery. Nevertheless, these intrusive strategies introduce the risk of brain injury, limiting their clinical application. In recent years, the intensive development of nanomaterials science and the interdisciplinary convergence of medical engineering have brought light to the penetration of the blood-brain barrier for brain-targeted drugs. In this paper, we extensively discuss the limitations of the blood-brain barrier on drug delivery and non-invasive brain-targeted strategies such as nanomedicine and blood-brain barrier disruption. In the meantime, we analyze their strengths and limitations and provide outlooks on the further development of brain-targeted drug delivery systems.

Degron-Based bioPROTACs for Controlling Signaling in CAR T Cells

Chimeric antigen receptor (CAR) T cells have made a tremendous impact in the clinic, but potent signaling through the CAR can be detrimental to treatment safety and efficacy. The use of protein degradation to control CAR signaling can address these issues in preclinical models. Existing strategies for regulating CAR stability rely on small molecules to induce systemic degradation. In contrast to small molecule regulation, genetic circuits offer a more precise method to control CAR signaling in an autonomous cell-by-cell fashion. Here, we describe a programmable protein degradation tool that adopts the framework of bioPROTACs, heterobifunctional proteins that are composed of a target recognition domain fused to a domain that recruits the endogenous ubiquitin proteasome system. We develop novel bioPROTACs that utilize a compact four-residue degron and demonstrate degradation of cytosolic and membrane protein targets using either a nanobody or synthetic leucine zipper as a protein binder. Our bioPROTACs exhibit potent degradation of CARs and can inhibit CAR signaling in primary human T cells. We demonstrate the utility of our bioPROTACs by constructing a genetic circuit to degrade the tyrosine kinase ZAP70 in response to recognition of a specific membrane-bound antigen. This circuit can disrupt CAR T cell signaling only in the presence of a specific cell population. These results suggest that bioPROTACs are powerful tools for expanding the CAR T cell engineering toolbox.

The next frontier in immunotherapy: potential and challenges of CAR-macrophages

Chimeric antigen receptor macrophage (CAR-MΦ) represents a significant advancement in immunotherapy, especially for treating solid tumors where traditional CAR-T therapies face limitations. CAR-MΦ offers a promising approach to target and eradicate tumor cells by utilizing macrophages' phagocytic and antigen-presenting abilities. However, challenges such as the complex tumor microenvironment (TME), variability in antigen expression, and immune suppression limit their efficacy. This review addresses these issues, exploring mechanisms of CAR-MΦ action, optimal construct designs, and interactions within the TME. It also delves into the ex vivo manufacturing challenges of CAR-MΦ, discussing autologous and allogeneic sources and the importance of stringent quality control. The potential synergies of integrating CAR-MΦ with existing cancer therapies like checkpoint inhibitors and conventional chemotherapeutics are examined to highlight possible enhanced treatment outcomes. Furthermore, regulatory pathways for CAR-MΦ therapies are scrutinized alongside established protocols for CAR-T cells, identifying unique considerations essential for clinical trials and market approval. Proposed safety monitoring frameworks aim to manage potential adverse events, such as cytokine release syndrome, crucial for patient safety. Consolidating current research and clinical insights, this review seeks to refine CAR-MΦ therapeutic applications, overcome barriers, and suggest future research directions to transition CAR-MΦ therapies from experimental platforms to standard cancer care options.

CD147-K148me2-Driven Tumor Cell-Macrophage Crosstalk Provokes NSCLC Immunosuppression via the CCL5/CCR5 Axis

Immunosuppression is a major hallmark of tumor progression in non-small cell lung cancer (NSCLC). Cluster of differentiation 147 (CD147), an important pro-tumorigenic factor, is closely linked to NSCLC immunosuppression. However, the role of CD147 di-methylation in the immunosuppressive tumor microenvironment (TME) remains unclear. Here, di-methylation of CD147 at Lys148 (CD147-K148me2) is identified as a common post-translational modification (PTM) in NSCLC that is significantly associated with unsatisfying survival outcomes among NSCLC sufferers, especially those in the advanced stages of the disease. The methyltransferase NSD2 catalyzes CD147 to generate CD147-K148me2. Further analysis demonstrates that CD147-K148me2 reestablishes the immunosuppressive TME and promotes NSCLC progression. Mechanistically, this modification promotes the interaction between cyclophilin A (CyPA) and CD147, and in turn, increases CCL5 gene transcription by activating p38-ZBTB32 signaling, leading to increased NSCLC cell-derived CCL5 secretion. Subsequently, CD147-K148me2-mediated CCL5 upregulation facilitates M2-like tumor-associated macrophage (TAM) infiltration in NSCLC tissues via CCL5/CCR5 axis-dependent intercellular crosstalk between tumor cells and macrophages, which is inhibited by blocking CD147-K148me2 with the targeted antibody 12C8. Overall, this study reveals the role of CD147-K148me2-driven intercellular crosstalk in the development of NSCLC immunosuppression, and provides a potential interventional strategy for PTM-targeted NSCLC therapy.

The roles of tertiary lymphoid structures in genitourinary cancers: molecular mechanisms, therapeutic strategies, and clinical applications

The presence of tertiary lymphoid structures (TLSs) associated with distinct treatment efficacy and clinical prognosis has been identified in various cancer types. However, the mechanistic roles and clinical implications of TLSs in genitourinary (GU) cancers remain incompletely explored. Despite their potential role as predictive markers described in numerous studies, it is essential to comprehensively evaluate the characteristics of TLSs, including drivers of formation, structural foundation, cellular compositions, maturation stages, molecular features, and specific functionality to maximize their positive impacts on tumor-specific immunity. The unique contributions of these structures to cancer progression and biology have fueled interest in these structures as mediators of antitumor immunity. Emerging data are trying to explore the effects of therapeutic interventions targeting TLSs. Therefore, a better understanding of the molecular and phenotypic heterogeneity of TLSs may facilitate the development of TLSs-targeting therapeutic strategies to obtain optimal clinical benefits for GU cancers in the setting of immunotherapy. In this review, the authors focus on the phenotypic and functional heterogeneity of TLSs in cancer progression, current therapeutic interventions targeting TLSs and the clinical implications and therapeutic potential of TLSs in GU cancers.

Macrophage-Derived Nanosponges Adsorb Cytokines and Modulate Macrophage Polarization for Renal Cell Carcinoma Immunotherapy

Renal cell carcinoma (RCC) is a hot tumor infiltrated by large numbers of CD8+ T cells and is highly sensitive to immunotherapy. However, tumor-associated macrophages (TAMs), mainly M2 macrophages, tend to undermine the efficacy of immunotherapy and promote the progression of RCC. Here, macrophage-derived nanosponges are fabricated by M2 macrophage membrane-coated poly（lactic-co-glycolic acid）（PLGA）, which could chemotaxis to the CXC and CC chemokine subfamily-enriched RCC microenvironment via corresponding membrane chemokine receptors. Subsequently, the nanosponges act like cytokine decoys to adsorb and neutralize broad-spectrum immunosuppressive cytokines such as colony stimulating factor-1(CSF-1), transforming growth factor-β（TGF-β）, and Lnterleukin-10（IL-10）, thereby reversing the polarization of M2-TAMs toward the pro-inflammatory M1 phenotype, and enhancing the anti-tumor effect of CD8+ T cells. To further enhance the polarization reprogramming efficiency of TAMs, DSPE-PEG-M2pep is conjugated on the surface of macrophage-derived nanosponges for specific recognition of M2-TAMs, and the toll like receptors 7/8（TLR7/8） agonist, R848, is encapsulated in these nanosponges to induce M1 polarization, which result in significant efficacy against RCC. In addition, these nanosponges exhibit undetectable biotoxicity, making them suitable for clinical applications. In summary, a promising and facile strategy is provided for immunomodulatory therapies, which are expected to be used in the treatment of tumors, autoimmune diseases, and inflammatory diseases.

Insights into chemical components, health-promoting effects, and processing impact of golden chanterelle mushroom Cantharellus cibarius

Cantharellus cibarius (CC) is a culinary mushroom with significant commercial potential due to its diverse components and bioactive functions. CC is rich in carbohydrates, proteins, minerals, vitamins, and aroma compounds while being low in fat and calories. Moreover, CC contains an abundance of bioactive substances including phenolic compounds, vitamin precursors, and indole derivatives. Numerous studies have claimed that CC has diverse functions such as antioxidant, antimicrobial, immunoregulation, anti-inflammatory, antitumor, neuroprotective, antidiabetic, and prebiotic effects in in vivo or in vitro settings. In addition, a variety of thermal, physical, chemical, and biological treatment methods have been investigated for the processing and preservation of CC. Consequently, this study aims to present a comprehensive review of the chemical composition, health benefits, and processing techniques of CC. Furthermore, the issue of heavy metal accumulation in CC has been indicated and discussed. The study highlights the potential of CC as a functional food in the future while providing valuable insights for future research and identifying areas requiring further investigation.

Recent breakthroughs in graphene quantum dot-enhanced sonodynamic and photodynamic therapy

Water-soluble graphene quantum dots (GQDs) have recently exhibited considerable potential for diverse biomedical applications owing to their exceptional optical and chemical properties. However, the pronounced heterogeneity in the composition, size, and morphology of GQDs poses challenges for a comprehensive understanding of the intricate correlation between their structural attributes and functional properties. This variability also introduces complexities in scaling the production processes and addressing safety considerations. Light and sound have firmly established their role in clinical applications as pivotal energy sources for minimally invasive therapeutic interventions. Given the limited penetration depth of light, photodynamic therapy (PDT) predominantly targets superficial conditions such as dermatological disorders, head and neck malignancies, ocular ailments, and early-stage esophageal cancer. Conversely, ultrasound-based sonodynamic therapy (SDT) capitalizes on its superior ability to propagate and focus ultrasound within biological tissues, enabling a diverse range of therapeutic applications, including the management of gliomas, breast cancer, hematological tumors, and modulation of the blood-brain barrier (BBB). Considering the advancements in theranostic and precision therapies, reevaluating these conventional energy sources and their associated sensitizers is imperative. This review introduces three prevalent treatment modalities that harness light and sound stimuli: PDT, SDT, and a synergistic approach that integrates PDT and SDT. This study delineated the therapeutic dynamics and contemporary designs of sensitizers tailored to these modalities. By exploring the historical context of the field and elucidating the latest design strategies, this review underscores the pivotal role of GQDs in propelling the evolution of PDT and SDT. This aspires to stimulate researchers to develop "multimodal" therapies integrating both light and sound stimuli.

Activating innate immune responses repolarizes hPSC-derived CAR macrophages to improve anti-tumor activity

Generation of chimeric antigen receptor macrophages (CAR-Ms) from human pluripotent stem cells (hPSCs) offers new prospects for cancer immunotherapy but is currently challenged by low differentiation efficiency and limited function. Here, we develop a highly efficient monolayer-based system that can produce around 6,000 macrophages from a single hPSC within 3 weeks. Based on CAR structure screening, we generate hPSC-CAR-Ms with stable CAR expression and potent tumoricidal activity in vitro. To overcome the loss of tumoricidal activity of hPSC-CAR-Ms in vivo, we use interferon-γ and monophosphoryl lipid A to activate an innate immune response that repolarizes the hPSC-CAR-Ms to tumoricidal macrophages. Moreover, through combined activation of T cells by hPSC-CAR-Ms, we demonstrate that activating a collaborative innate-adaptive immune response can further enhance the anti-tumor effect of hPSC-CAR-Ms in vivo. Collectively, our study provides feasible methodologies that significantly improve the production and function of hPSC-CAR-Ms to support their translation into clinical applications.