TAM-targeted reeducation for enhanced cancer immunotherapy: Mechanism and recent progress

The selection of animal models influences the assessment of anti-tumor efficacy: promising sialic acid-conjugate modified liposomes demonstrate remarkable therapeutic effects in diverse mouse strains

Mice as a crucial tool for preclinical assessment of antineoplastic agents. The impact of physiological differences among mouse strains on the in vivo efficacy of antitumor drugs, however, has been significantly overlooked. Mononuclear phagocyte system (MPS) is the major player in clearance in vivo, and differences in MPS among different strains may potentially impact the effectiveness of antitumor preparations. Therefore, in this study, we employed conventional liposomes (CL-EPI) and SA-ODA modified liposomes (SAL-EPI) as model preparations to investigate the comprehensive tumor therapeutic effects of CL-EPI and SAL-EPI in KM, BALB/c, and C57BL/6 tumor-bearing mice. The results demonstrated significant variability in the efficacy of CL-EPI for tumor treatment across different mouse strains. Therefore, we should pay attention to the selection of animal models in the study of antitumor agents. SAL-EPI effectively targeted tumor sites by binding to Siglec-1 on the surface of peripheral blood monocytes (PBMs), and achieved good therapeutic effect in different mouse strains with little difference in treatment. The SA modified preparation is therefore expected to achieve a favorable therapeutic effect in tumor patients with different immune states through PBMs delivery (Siglec-1 was expressed in both mice and humans), thereby possessing clinical translational value and promising development prospects.

Applications of self-assembled peptide hydrogels in anti-tumor therapy

Peptides are a class of active substances composed of a variety of amino acids with special physiological functions. The rational design of peptide sequences at the molecular level enables their folding into diverse secondary structures. This property has garnered significant attention in the biomedical sphere owing to their favorable biocompatibility, adaptable mechanical traits, and exceptional loading capabilities. Concurrently with advancements in modern medicine, the diagnosis and treatment of tumors have increasingly embraced targeted and personalized approaches. This review explores recent applications of self-assembled peptides derived from natural amino acids in chemical therapy, immunotherapy, and other adjunctive treatments. We highlighted the utilization of peptide hydrogels as delivery systems for chemotherapeutic drugs and other bioactive molecules and then discussed the challenges and prospects for their future application.

Hsa_circ_0010882 facilitates hepatocellular carcinoma progression by modulating M1/M2 macrophage polarization

Hepatocellular carcinoma (HCC) is one common malignant tumour with a high immunosuppressive tumour microenvironment and poor outcomes. This study investigated the influence of hsa_circ_0010882 on M1/M2 macrophage polarization in the progression of HCC. A total of 125 paired tissue specimens from HCC patients who underwent hepatectomy were collected. M1 and M2 phenotypes macrophages were induced using THP-1. After co-cultured with macrophages and transfected HCC cells, the viability, migration and invasion of HCC cells were detected by cellular experiments. Bioinformatic databases and dual-luciferase reporter assays were used to predict and validate the interaction between circ_0010882 and miR-382. Expression of circ_0010882 was increased in HCC tissues and associated with shorter overall survival outcomes. The mRNA expression of M2 macrophage markers Arg-1, CD163 and CD206 were elevated in HCC tissues. Interfering with circ_0010882 increased M1-type macrophage markers (TNF-α and iNOS) while decreasing M2-type macrophage markers (Arg-1 and CD206). Silencing of circ_0010882 strengthened the capacity of M1 macrophages to suppress HCC cell viability, migration capacities and invasion potential while reducing the ability of M2 macrophages to promote above cellular abilities. MiR-382 was a direct target miRNA of circ_0010882. The circ_0010882 expression was increased in HCC tissues and associated with poor prognosis of HCC patients. Silencing of circ_0010882 inhibits macrophage M2 polarization in HCC progression by regulating miR-382 expression. Circ_0010882 may serve as a biomarker to provide novel strategies for the treatment of HCC and patient rehabilitation, thereby improving the prognosis of patients.

Reprogramming of tumor-associated macrophages via NEDD4-mediated CSF1R degradation by targeting USP18

Tumor-associated myeloid cells modulate the tumor microenvironment and affect tumor progression. Type I interferon (IFN-I) has multiple effects on tumors and immune response, and ubiquitin-specific peptidase 18 (USP18) functions as a negative regulator of IFN-I signal transduction. This study aims to examine the function of IFN-I in myeloid cells during tumor progression. Here, we show that deletion of USP18 in myeloid cells suppresses tumor progression. Enhanced IFN-I signaling and blocked USP18 expression prompt downregulation of colony stimulating factor 1 receptor (CSF1R) and polarization of tumor-associated macrophages toward pro-inflammatory phenotypes. Further in vitro experiments reveal that downregulation of CSF1R is mediated by ubiquitin-proteasome degradation via E3 ligase neural precursor cell-expressed, developmentaly downregulated 4 (NEDD4) and the IFN-induced increase in ubiquitin E2 ubiquitin-conjugating enzyme H5. USP18 impairs ubiquitination and subsequent degradation of CSF1R by interrupting NEDD4 binding to CSF1R. These results reveal a previously unappreciated role of IFN-I in macrophage polarization by regulating CSF1R via USP18 and suggest targeting USP18 in myeloid-lineage cells as an effective strategy for IFN-based therapies.

Biological function, regulatory mechanism, and clinical application of mannose in cancer

Studies examining the regulatory roles and clinical applications of monosaccharides other than glucose in cancer have been neglected. Mannose, a common type of monosaccharide found in human body fluids and tissues, primarily functions in protein glycosylation rather than carbohydrate metabolism. Recent research has demonstrated direct anticancer effects of mannose in vitro and in vivo. Simply supplementing cell culture medium or drinking water with mannose achieved these effects. Moreover, mannose enhances the effectiveness of current cancer treatments including chemotherapy, radiotherapy, targeted therapy, and immune therapy. Besides the advancements in basic research on the anticancer effects of mannose, recent studies have reported its application as a biomarker for cancer or in the delivery of anticancer drugs using mannose-modified drug delivery systems. This review discusses the progress made in understanding the regulatory roles of mannose in cancer progression, the mechanisms underlying its anticancer effects, and its current application in cancer diagnosis and treatment.

Subverted macrophages in the triple-negative breast cancer ecosystem

Tumor-associated macrophages (TAMs) are the most critical effector cells of innate immunity and the most abundant tumor-infiltrating immune cells. They play a key role in the clearance of apoptotic bodies, regulation of inflammation, and tissue repair to maintain homeostasis in vivo. With the progression of triple-negative breast cancer（TNBC）, TAMs are "subverted" from tumor-promoting immune cells to tumor-promoting immune suppressor cells, which play a significant role in tumor development and are considered potential targets for cancer therapy. Here, we explored how macrophages, as the most important part of the TNBC ecosystem, are "subverted" to drive cancer evolution and the uniqueness of TAMs in TNBC progression and metastasis. Similarly, we discuss the rationale and available evidence for TAMs as potential targets for TNBC therapy.

Monocytes in Tumorigenesis and Tumor Immunotherapy

Monocytes are highly plastic innate immune cells that display significant heterogeneity during homeostasis, inflammation, and tumorigenesis. Tumor-induced systemic and local microenvironmental changes influence the phenotype, differentiation, and distribution of monocytes. Meanwhile, monocytes and their related cell subsets perform an important regulatory role in the development of many cancers by affecting tumor growth or metastasis. Thanks to recent advances in single-cell technologies, the nature of monocyte heterogeneity and subset-specific functions have become increasingly clear, making it possible to systematically analyze subset-specific roles of monocytes in tumorigenesis. In this review, we discuss recent discoveries related to monocytes and tumorigenesis, and new strategies for tumor biomarker identification and anti-tumor immunotherapy.

The role of metabolic reprogramming of tumor-associated macrophages in shaping the immunosuppressive tumor microenvironment

Macrophages are potent immune effector cells in innate immunity and exert dual-effects in the tumor microenvironment (TME). Tumor-associated macrophages (TAMs) make up a significant portion of TME immune cells. Similar to M1/M2 macrophages, TAMs are also highly plastic, and their functions are regulated by cytokines, chemokines and other factors in the TME. The metabolic changes in TAMs are significantly associated with polarization towards a protumour or antitumour phenotype. The metabolites generated via TAM metabolic reprogramming in turn promote tumor progression and immune tolerance. In this review, we explore the metabolic reprogramming of TAMs in terms of energy, amino acid and fatty acid metabolism and the potential roles of these changes in immune suppression.

Targeted delivery of pexidartinib to tumor-associated macrophages via legumain-sensitive dual-coating nanoparticles for cancer immunotherapy

Tumor-associated macrophage (TAM) is regarded as an appealing cell target for cancer immunotherapy. However, it remains challenging to selectively eliminate M2-like TAM in tumor microenvironment. In this work, we employed a legumain-sensitive dual-coating nanosystem (s-T_pep-NPs) to deliver CSF-1R inhibitor pexidartinib (PLX3397) for targeting TAM therapy. The PLX3397-loaded NPs exhibited uniform size of ∼240 nm in diameter, good drug loading capacity and efficiency, as well as sustained drug release profile. Compared to non-sensitive counterpart ns-T_pep-NPs, s-T_pep-NPs showed distinguished selectivity upon M1 and M2 macrophage uptake with relation to incubation time and dose. Besides, the selectivity of anti-proliferation effect was also identified for s-T_pep-NPs against M1 and M2 macrophage. In vivo imaging demonstrated that s-T_pep-NPs exhibited much higher tumoral accumulation and TAM recognition specificity as compared to non-sensitive ns-T_pep-NPs. In vivo efficacy verified that s-T_pep-NPs formulation was much more effective than ns-T_pep-NPs and other PLX3397 formulations to treat B16F10 melanoma via targeting TAM depletion and modulating tumor immune microenvironment. Overall, this study provides a robust and promising nanomedicine strategy for TAM-targeted cancer immunotherapy.

Association between Intratumoral CD8+ T Cells with FoxP3+ and CD163+ Cells: A Potential Immune Intrinsic Negative Feedback Mechanism for Acquired Immune Resistance

Acquired immune resistance (AIR) describes a situation in which cancer patients who initially responded clinically to immunotherapies, after a certain period of time, progress with their disease. Considering that AIR represents a feedback response of the tumor against the immune attack generated during the course of immunotherapies, it is conceivable that AIR may also occur before treatment initiation as a mechanism to escape endogenous adaptive antitumor immunity (EAAI). In the present study, we assessed the EAAI in paraffin-embedded breast primary tumor tissue samples and drew correlations with the clinical outcomes. In particular, we analyzed densities of CD8+ cells as elements mediating antitumor cytotoxicity, and of CD163+ and FoxP3+ cells as suppressor elements. We found a direct correlation between the densities of CD8+ cells and of CD163+ and/or FoxP3+ cells in the vast majority of patients' tumors. Importantly, the vast majority of patients whose tumors were overpopulated by CD8+ cells developed AIR, which was characterized by high intratumoral CD163+ and/or FoxP3+ cell densities and reduced overall survival (OS). We also showed that AIR depends on the levels of CD8+ cell-ratios in the tumor center to the invasive margin. Our data suggest that tumors develop AIR only when under a robust endogenous immune pressure.