The role of macrophage in regulating tumour microenvironment and the strategies for reprogramming tumour-associated macrophages in antitumour therapy

Integrins and integrin-driven secretory pathways as multi-dimensional regulators of tumor-associated macrophage recruitment and reprogramming in tumor microenvironment

Integrins, a group of transmembrane receptors, play a crucial role in mediating the interactions between cells and extracellular matrix (ECM) proteins. The intracellular signaling initiated by these cell-matrix interactions in leukocytes mediates many essential cellular processes such as survival, migration, metabolism, and other immunological functions. Macrophages, as phagocytes, participate in both proinflammatory and anti-inflammatory processes, including progression. Numerous reports have shown that the integrin-regulated secretome, comprising cytokines, chemokines, growth factors, proteases, and other bioactive molecules, is a crucial modulator of macrophage functions in tumors, significantly influencing macrophage programming and reprogramming within the tumor microenvironment (TME) in addition to driving their step-by-step entry process into tumor tissue spaces. Importantly, studies have demonstrated a pivotal role for integrin receptor-mediated secretome and associated signaling pathways in functional reprogramming from anti-tumorigenic to pro-tumorigenic phenotype in tumor-associated macrophages (TAMs). In this comprehensive review, we have provided an in-depth analysis of the latest findings of various key pathways, mediators, and signaling cascades associated with integrin-driven polarization of macrophages in tumors. This manuscript will provide an updated understanding of the modulation of inflammatory monocytes/ macrophages and TAMs by integrin-driven secretory pathways in various functions such as migration, differentiation, and their role in tumor progression, angiogenesis, and metastasis.

Unconventional p65/p52 NF-κB module regulates key tumor microenvironment-related genes in breast tumor-associated macrophages (TAMs)

The complex heterogeneity of tumor microenvironment (TME) of triple-negative breast cancer (TNBC) presents a significant obstacle to cytotoxic immune response and successful treatment, building up one of the most hostile oncological phenotypes. Among the most abundant TME components, tumor-associated macrophages (TAMs) have pivotal pro-tumoral functions, involving discordant roles for the nuclear factor kappa-B (NF-κB) transcription factors and directing to higher levels of pathway complexity. In both resting macrophages and TAMs, we recently revealed the existence of the uncharacterized NF-κB p65/p52 dimer. In the present study, we demonstrated its enhanced active nuclear localization in TAMs and validated selected immune target genes as directly regulated by dimer binding on DNA sequences. We demonstrated by ChIP-qPCR that p65/p52 enrichment on HSPG2 and CSF-1 regulatory regions is strictly dependent on macrophage polarization and tumor environment. Our data provide novel mechanisms of transcriptional regulation in TAMs, orchestrated by the varied and dynamic nature of NF-κB combinations, which needs to be considered when targeting this pathway in cancer therapies. Our results offer p65/p52, together with identified regulatory regions on genes impacting macrophage behavior and tumor biology, as novel molecular targets for TNBC, aimed at modulating TAMs functions towards anti-tumoral phenotypes and thus improving cancer treatment outcomes.

CAR Macrophages: a promising novel immunotherapy for solid tumors and beyond

With the advent of adoptive cellular therapy, chimeric antigen receptor (CAR)-T cell therapy has gained widespread application in cancer treatment and has demonstrated significant efficacy against certain hematologic malignancies. However, due to the limitations of CAR-T cell therapy in treating solid tumors, other immune cells are being modified with CAR to address this issue. Macrophages have emerged as a promising option, owing to their extensive immune functions, which include antigen presentation, powerful tumor phagocytosis, and particularly active trafficking to the tumor microenvironment. Leveraging their unique advantages, CAR-macrophages (CAR-M) are expected to enhance the effectiveness of solid tumor treatments as a novel form of immunotherapy, potentially overcoming major challenges associated with CAR-T/NK therapy. This review outlines the primary mechanism underlying CAR-M and recent progressions in CAR-M therapy, while also discussing their further applications.

Emerging Innate Immune Cells in Cancer Immunotherapy: Promises and Challenges

Immune checkpoint inhibitor (ICI)-based therapy has made an unprecedented impact on survival benefit for a subset of cancer patients; however, only a subset of cancer patients is benefiting from ICI therapy if all cancer types are considered. With the advanced understanding of interactions of immune effector cell types and tumors, cell-based therapies are emerging as alternatives to patients who could not benefit from ICI therapy. Pioneering work of chimeric antigen receptor T (CAR-T) therapy for hematological malignancies has brought encouragement to a broad range of development for cellular-based cancer immunotherapy, both innate immune cell-based therapies and T-cell-based therapies. Innate immune cells are important cell types due to their rapid response, versatile function, superior safety profiles being demonstrated in early clinical development, and being able to utilize multiple allogeneic cell sources. Efforts on engineering innate immune cells and exploring their therapeutic potential are rapidly emerging. Some of the therapies, such as CD19 CAR natural killer (CAR-NK) cell-based therapy, have demonstrated comparable early efficacy with CD19 CAR-T cells. These studies underscore the significance of developing innate immune cells for cancer therapy. In this review, we focus on the current development of emerging NK cells, γδ T cells, and macrophages. We also present our views on potential challenges and perspectives to overcome these challenges.

Immunohistochemical Profiling of SSTR2 and HIF-2α with the Tumor Microenvironment in Pheochromocytoma and Paraganglioma

Metastatic pheochromocytomas and paragangliomas (PPGLs) are rare endocrine malignancies with limited effective treatment options. The association between the tumor microenvironment (TME) with somatostatin receptor 2 (SSTR2) and hypoxia-induced factor-2α (HIF-2α) in PPGLs, critical for optimizing combination therapeutic strategies with immunotherapy, remains largely unexplored. To evaluate the association of SSTR2 and HIF-2α immunoreactivity with the TME in patients with PPGLs, we analyzed the expression of SSTR2A, HIF-2α, and TME components, including tumor-infiltrating lymphocytes (CD4 and CD8), tumor-associated macrophages (CD68 and CD163), and PD-L1, using immunohistochemistry in patients with PPGLs. The primary outcome was to determine the association of the immune profiles with SSTR2A and HIF-2α expression. Among 45 patients with PPGLs, SSTR2A and HIF2α were positively expressed in 21 (46.7%) and 14 (31.1%) patients, respectively. The median PD-L1 immunohistochemical score (IHS) was 2.0 (interquartile range: 0-30.0). Positive correlations were observed between CD4, CD8, CD68, and CD163 levels. A negative correlation was found between the CD163/CD68 ratio (an indicator of M2 polarization) and SSTR2A expression (r = -0.385, p = 0.006). HIF-2α expression showed a positive correlation with PD-L1 IHS (r = 0.348, p = 0.013). The co-expression of PD-L1 (HIS > 10) and HIF-2α was found in seven patients (15.6%). No associations were observed between SDHB staining results and the CD163/CD68 ratio, PD-L1, or SSTR2A expression. Our data suggest the potential of combination therapy with immunotherapy and peptide receptor radionuclide therapy or HIF-2α inhibitors as a treatment option in selected PPGL populations.

Comprehensive Proteomics Analysis Reveals Dynamic Phenotypes of Tumor-Associated Macrophages and Their Precursor Cells in Tumor Progression

Tumor-associated macrophages (TAMs) are key regulators in tumor progression, but the precise role of bone marrow-derived monocytes (Mons) as TAM precursors and their dynamic phenotypes regulated by the tumor microenvironment (TME) remain unclear. Here, we developed an optimized microproteomics workflow to analyze low-cell-number mouse myeloid cells. We sorted TAMs and their corresponding Mons (1 × 105 per sample) from individual melanoma mouse models at both the early and late stages. We established the protein expression profiles for these cells by mass spectrometry. Subsequently, we analyzed the dynamics phenotypes of TAMs and identified a characteristic protein expression profile characterized by upregulated cholesterol metabolism and downregulated immune responses during tumor progression. Moreover, we found the downregulation of both STAT5 and PYCARD expression not only in late-stage TAMs but also in late-stage Mons, indicating a loss of the ability to induce inflammatory responses prior to Mons infiltration into TME. Taken together, our study provides valuable insights into the progression-dependent transitions between TAMs and their precursor cells, as well as the cross-organ communications of tumor and bone marrow.

Magnetic-driven Interleukin-4 internalization promotes magnetic nanoparticle morphology and size-dependent macrophage polarization

Macrophages are known to depict two major phenotypes: classically activated macrophages (M1), associated with high production of pro-inflammatory cytokines, and alternatively activated macrophages (M2), which present an anti-inflammatory function. A precise control over M1-M2 polarization is a promising strategy in therapeutics to modulate both tissue regeneration and tumor progression processes. However, this is not a simple task as macrophages behave differently depending on the microenvironment. In agreement with this, non-consistent data have been reported regarding macrophages response to magnetic iron oxide nanoparticles (MNPs). To investigate the impact of both tissue microenvironment and MNPs properties on the obtained macrophage responses, single-core (SC) and multi-core (MC) citrate coated MNPs, are synthesized and, afterwards, loaded with a macrophage polarization trigger, IL-4. The developed MNPs are then tested in macrophages subjected to different stimuli. We demonstrate that macrophages treated with low concentrations of MNPs behave differently depending on the polarization stage independently of the concentration of iron. Moreover, we find out that MNPs size and morphology determines the effect of the IL-4 loaded MNPs on M1 macrophages, since IL-4 loaded SC MNPs favor the polarization of M1 macrophages towards M2 phenotype, while IL-4 loaded MC MNPs further stimulate the secretion of pro-inflammatory cytokines.

Cuproptosis and cuproptosis-related genes: Emerging potential therapeutic targets in breast cancer

Breast cancer is one of the most common malignant tumors in women worldwide, and thus, it is important to enhance its treatment efficacy [1]. Copper has emerged as a critical trace element that affects various intracellular signaling pathways, gene expression, and biological metabolic processes [2], thereby playing a crucial role in the pathogenesis of breast cancer. Recent studies have identified cuproptosis, a newly discovered type of cell death, as an emerging therapeutic target for breast cancer treatment, thereby offering new hope for breast cancer patients. Tsvetkov's research has elucidated the mechanism of cuproptosis and uncovered the critical genes involved in its regulation [3]. Manipulating the expression of these genes could potentially serve as a promising therapeutic strategy for breast cancer treatment. Additionally, using copper ionophores and copper complexes combined with nanomaterials to induce cuproptosis may provide a potential approach to eliminating drug-resistant breast cancer cells, thus improving the therapeutic efficacy of chemotherapy, radiotherapy, and immunotherapy and eventually eradicating breast tumors. This review aims to highlight the practical significance of cuproptosis-related genes and the induction of cuproptosis in the clinical diagnosis and treatment of breast cancer. We examine the potential of cuproptosis as a novel therapeutic target for breast cancer, and we explore the present challenges and limitations of this approach. Our objective is to provide innovative ideas and references for the development of breast cancer treatment strategies based on cuproptosis.

Immune landscape and immunotherapy for penile cancer

Penile cancer is a rare malignancy and usually refers to penile squamous cell carcinoma (PSCC), which accounts for more than 95% of all penile malignancies. Although organ-sparing surgery is an effective treatment for early-stage PSCC, surgical intervention alone is often not curative for advanced PSCC with metastases to the inguinal and/or pelvic lymph nodes; thus, systemic therapy is required (usually platinum-based chemotherapy and surgery combined). However, chemotherapy for PSCC has proven to be of limited efficacy and is often accompanied by high toxicity, and patients with advanced PSCC usually have poor prognosis. The limited treatment options and poor prognosis indicate the unmet need for advanced PSCC. Immune-based therapies have been approved for a variety of genitourinary and squamous cell carcinomas but are rarely reported in PSCC. To date, several studies have reported high expression of PDL1 in PSCC, supporting the potential application of immune checkpoint inhibitors in PSCC. In addition, human papillomavirus (HPV) infection is highly prevalent in PSCC and plays a key role in the carcinogenesis of HPV-positive PSCC, suggesting that therapeutic HPV vaccine may also be a potential treatment modality. Moreover, adoptive T cell therapy (ATC) has also shown efficacy in treating advanced penile cancer in some early clinical trials. The development of new therapeutics relies on understanding the underlying biological mechanisms and processes of tumor initiation, progression and metastasis. Therefore, based on the interest, we reviewed the tumor immune microenvironment and the emerging immunotherapy for penile cancer.

Caerin 1.1/1.9 Enhances Antitumour Immunity by Activating the IFN-α Response Signalling Pathway of Tumour Macrophages

Macrophages are one of the essential components of the tumour microenvironment (TME) of many cancers and show complex heterogeneity and functions. More recent research has been focusing on the characterisation of tumour-associated macrophages (TAMs). Previously, our study demonstrated that caerin 1.1/1.9 peptides significantly improve the therapeutic efficacy of combined specific immunotherapy and immune checkpoint blockade in a murine transplantable tumour model (TC-1). In this study, the mice inoculated with TC-1 tumour were immunised differently. The TAMs were isolated using flow cytometry and characterised by cytokine ELISA. The survival rates of mice with different treatments containing caerin 1.1/19 were assessed comparatively, including those with/without macrophage depletion. The single-cell RNA sequencing (scRNA-seq) data of previous studies were integrated to further reveal the functions of TAMs with the treatments containing caerin 1.1/1.9. As a comparison, the TAMs of stage I and II cervical cancer patients were analysed using scRNA-seq analysis. We demonstrate that caerin induced tumour clearance is associated with infiltration of tumours by IL-12 secreting Ly6C+F4/80+ macrophages exhibiting enhanced IFN-α response signalling, renders animals resistant to further tumour challenge, which is lost after macrophage depletion. Our results indicate that caerin 1.1/1.9 treatment has great potential in improving current immunotherapy efficacy.

Outer Membrane Vesicles Coating Nano-Glycyrrhizic Acid Confers Protection Against Borderella bronchiseptica Through Th1/Th2/Th17 Responses

Purpose

Outer membrane vesicles (OMVs) are spherical nano-sized proteolipids secreted by numerous pathogenic Gram-negative bacteria. Due to the immunostimulatory properties and protective efficacy, OMVs have received increasing attention as a candidate for the vaccine to prevent and treat bacterial infections. However, the immune response remains elusive due to the low structural stability and poor size homogeneity of the vesicles. In this study, OMVs were used to coat self-assembled glycyrrhizic acid nanoparticles (GANs) and obtain a stable OMV vaccine. The immunoprotective effects and anti-infection efficacy were evaluated in vivo and in vitro.

Methods

The OMVs were prepared by ultrafiltration method and fused with GAN through mechanical extrusion. The characteristics, including morphology, hydrodynamic size, zeta potential, and stability were evaluated. The in vitro immunological function of GAN-OMV on the macrophages and in vivo immune efficacy and anti-infection effect were examined and compared.

Results

The results showed that the GAN-OMV were homogenous with a size of 130 nm and a stable core-shell structure. Micropinocytosis-dependent and clathrin-mediated endocytotic pathways effectively internalized the GAN-OMV into the macrophages and promoted cell proliferation, cytokine secretion, and M1 polarization. Furthermore, subcutaneous GAN-OMV vaccination contributed to significantly higher Borderella bronchiseptica (Bb)-specific antibody production and lymphocyte proliferation. The splenic lymphocytes of mice immunized with GAN-OMVs displayed a higher ratio of CD4+/CD8+ T cells and CD19+ B cells and produced significantly higher levels of Th1/Th2/Th17 cytokines. GAN-OMV also effectively prevented Bb reinfection.

Conclusion

In this study, GAN-OMV was developed successfully to stimulate Th1/Th2/Th17 immune responses against Bb and provide a promising strategy for novel vaccine development against the microbial pathogen.

Chamaejasmenin B, an Inhibitor for Metastatic Outgrowth, Reversed M2-Dominant Macrophage Polarization in Breast Tumor Microenvironment

Metastasis is a multistep process that depends on the interactions between tumor cells and their microenvironment. Macrophages in the tumor microenvironment show high polarization plasticity and have a paradoxical role in cancer progression. Hijacked by tumor-promoting signals, the polarization status of macrophages was pathologically disturbed and believed to be the decisive mechanism forcing the progression of metastasis. In this study, we explored the immunological activity of Chamaejasmin B (ICJ), a previously proved inhibitor for metastasis, in macrophages from metastatic microenvironment. When intravenously injected of 4T1 cells in mice, ICJ significantly inhibited its metastatic outgrowth. Taking tumor cell and macrophage as a functional integrity, an adoptive transfer model was established in vitro to exclude the direct effect of ICJ on tumor. The findings suggest a dual influence of ICJ on both tumors and macrophages, as indicated by the rebalance of macrophage polarization and suppression of clonogenic potential in tumor cells. Mechanistically, ICJ redirected M2-dominant polarization of tumor-associated macrophage in an IL-4-mTOR-dependent manner. Collectively, our study revealed that ICJ rebalanced macrophage polarization in malignant microenvironment and showed promising effect in suppressing metastatic outgrowth in breast cancer model.

Inflammatory level under different p53 mutation status and the regulation role of curcumin in tumor microenvironment

The inflammation is tightly associated with tumor development, promoting or inhibiting tumorigenesis. And mutant p53 is speculated to promote inflammation and tumorigenesis. The tumor associated macrophages are usually educated to present the anti-inflammatory profile to tune down antitumor immunity. However, the impact of p53 mutants on macrophages is not clear. Here, we compared the basal inflammatory level and macrophage profiles in tumor cells and tumor samples with different p53 mutations. Data revealed that a lower inflammatory level was maintained in immune organs and tumor cells with p53 point mutations than those with p53 null mutation. Using the tumor cell-derived conditional media to culture macrophages, we found that the media from cells with p53 mutations, especially the point mutations, could decrease M1 markers and inhibit phagocytosis, suggesting the p53 mutation promoted M2 profile polarization. To target the p53 mutation induced M2 macrophage polarization, we applied low-concentration curcumin to the tumor cells with different p53 mutations. The data showed that curcumin could inhibit STAT3 signal and decrease PPARγ and CSF1 in tumor cells and tumor samples. In vitro, the co-culture assays showed that the curcumin treatment shifted p53 mutation educated macrophages back towards M1 profile. In vivo, the curcumin-treated MEFs showed obvious tumor inhibition, and the tumor samples displayed inhibited M2 markers. Results suggested that curcumin could inhibit p53 mutation educated macrophage induction and suppress M2-promoted tumorigenesis. Our study illustrated the inflammatory level under different p53 status and the inflammatory regulated role of curcumin in tumor environment. This study might provide a potential method in tumor personalized treatment aiming immune therapy in different p53 status.