Inhibition of macrophage-mediated phagocytosis has emerged as an essential mechanism for tumor immune evasion. One mechanism inhibiting the innate response is the presence of the macrophage inhibitory molecule, signal regulatory protein-α (SIRPα), on tumor-associated macrophages (TAMs) and its cognate ligand cluster of differentiation 47 (CD47) on tumor cells in the tumor microenvironment. On the basis of a recently discovered programmed death protein 1 (PD-1) in TAMs, we discuss the potential inhibitory receptors that possess new functions beyond T cell exhaustion in this review. As more and more immune receptors are found to be expressed on TAMs, the corresponding therapies may also stimulate macrophages for phagocytosis and thereby provide extra anti-tumor benefits in cancer therapy. Therefore, identification of biomarkers and combinatorial therapeutic strategies, have the potential to improve the efficacy and safety profiles of current immunotherapies.
Antigens, Surface ; metabolism ; Apoptosis Regulatory Proteins ; metabolism ; Humans ; Immunotherapy ; methods ; Macrophages ; immunology ; Neoplasms ; immunology ; pathology ; therapy ; Phagocytosis ; immunology ; Treatment Outcome ; Tumor Microenvironment ; immunology

Metastasis is the leading cause of death in breast cancer patients. However, the mechanisms underlying metastasis are not well understood and there is no effective treatment in the clinic. Here, we demonstrate that in MMTV-PyMT, a highly malignant spontaneous breast tumor model, IL-25 (also called IL-17E) was expressed by tumor-infiltrating CD4 T cells and macrophages. An IL-25 neutralization antibody, while not affecting primary tumor growth, substantially reduced lung metastasis. Inhibition of IL-25 resulted in decreased type 2 T cells and macrophages in the primary tumor microenvironments, both reported to enhance breast tumor invasion and subsequent metastasis to the lung. Taken together, our data suggest IL-25 blockade as a novel treatment for metastatic breast tumor.
Animals ; Antibodies, Neoplasm ; pharmacology ; Antibodies, Neutralizing ; pharmacology ; Breast Neoplasms ; drug therapy ; genetics ; immunology ; CD4-Positive T-Lymphocytes ; immunology ; pathology ; Female ; Humans ; Interleukin-17 ; antagonists & inhibitors ; genetics ; immunology ; Interleukins ; antagonists & inhibitors ; genetics ; immunology ; Macrophages ; immunology ; pathology ; Mammary Neoplasms, Animal ; drug therapy ; genetics ; immunology ; Mice ; Neoplasm Metastasis ; Tumor Microenvironment ; drug effects ; genetics ; immunology

Atherosclerosis is an inflammatory disease as well as a lipid disorder. Atherosclerotic plaque formed in vessel walls may cause ischemia, and the rupture of vulnerable plaque may result in fatal events, like myocardial infarction or stroke. Because morphological imaging has limitations in diagnosing vulnerable plaque, molecular imaging has been developed, in particular, the use of nuclear imaging probes. Molecular imaging targets various aspects of vulnerable plaque, such as inflammatory cell accumulation, endothelial activation, proteolysis, neoangiogenesis, hypoxia, apoptosis, and calcification. Many preclinical and clinical studies have been conducted with various imaging probes and some of them have exhibited promising results. Despite some limitations in imaging technology, molecular imaging is expected to be used both in the research and clinical fields as imaging instruments become more advanced.
Atherosclerosis/*diagnosis/pathology/radiography ; Endothelial Cells/metabolism ; Humans ; Inflammation/pathology ; Lipoproteins, LDL/metabolism ; Macrophages/immunology/metabolism ; Plaque, Atherosclerotic ; Positron-Emission Tomography ; Tomography, Emission-Computed, Single-Photon

The rising number of obese individuals has become a major burden to the healthcare systems worldwide. Obesity includes not only the increase of adipose tissue mass but importantly also the altered cellular functions that collectively lead to a chronic state of adipose tissue inflammation, insulin resistance and impaired wound healing. Adipose tissue undergoing chronic inflammation shows altered cytokine expression and an accumulation of adipose tissue macrophages (ATM). The macrophage migration inhibitory factor (MIF) superfamily consists of MIF and the recently identified homolog D-dopachrome tautomerase (D-DT or MIF-2). MIF and D-DT, which both bind to the CD74/CD44 receptor complex, are differentially expressed in adipose tissue and have distinct roles in adipogenesis. MIF positively correlates with obesity as well as insulin resistance and contributes to adipose tissue inflammation by modulating ATM functions. D-DT, however, is negatively correlated with obesity and reverses glucose intolerance. In this review, their respective roles in adipose tissue homeostasis, adipose tissue inflammation, insulin resistance and impaired wound healing will be reviewed.
Adipose Tissue/*immunology/pathology ; Animals ; Diabetes Mellitus/immunology/pathology ; Humans ; Inflammation/*immunology/pathology ; Insulin Resistance ; Intramolecular Oxidoreductases/analysis/*immunology ; Macrophage Migration-Inhibitory Factors/analysis/*immunology ; Macrophages/immunology/pathology ; Obesity/*immunology/pathology ; *Wound Healing

The rising number of obese individuals has become a major burden to the healthcare systems worldwide. Obesity includes not only the increase of adipose tissue mass but importantly also the altered cellular functions that collectively lead to a chronic state of adipose tissue inflammation, insulin resistance and impaired wound healing. Adipose tissue undergoing chronic inflammation shows altered cytokine expression and an accumulation of adipose tissue macrophages (ATM). The macrophage migration inhibitory factor (MIF) superfamily consists of MIF and the recently identified homolog D-dopachrome tautomerase (D-DT or MIF-2). MIF and D-DT, which both bind to the CD74/CD44 receptor complex, are differentially expressed in adipose tissue and have distinct roles in adipogenesis. MIF positively correlates with obesity as well as insulin resistance and contributes to adipose tissue inflammation by modulating ATM functions. D-DT, however, is negatively correlated with obesity and reverses glucose intolerance. In this review, their respective roles in adipose tissue homeostasis, adipose tissue inflammation, insulin resistance and impaired wound healing will be reviewed.
Adipose Tissue/*immunology/pathology ; Animals ; Diabetes Mellitus/immunology/pathology ; Humans ; Inflammation/*immunology/pathology ; Insulin Resistance ; Intramolecular Oxidoreductases/analysis/*immunology ; Macrophage Migration-Inhibitory Factors/analysis/*immunology ; Macrophages/immunology/pathology ; Obesity/*immunology/pathology ; *Wound Healing

Alternatively activated macrophages are more frequently involved in tumor growth, angiogenesis, and immunosuppression. A previous study showed that paeoniflorin, the major active constituent of Paeonia lactiflora Pallas, can inhibit tumor growth and lung metastases of Lewis lung tumor-bearing mice. This study tried to investigate whether paeoniflorin inhibited lung cancer metastasis by inhibiting the alternative activation of macrophages (M2 macrophage). Using a viability assay, the cytotoxicity of paeoniflorin on Lewis lung cancer cells and peritoneal macrophages were investigated. In vitro scratch wound and in vivo lung metastasis experiments were used to test the ability to inhibit the migration of paeoniflorin and the function of M2 macrophages. Flow cytometry was performed to test the cell cycle of Lewis lung cancer cells, and to test the M2 macrophages in peritoneal macrophages and subcutaneous transplantable tumor. It was found that paeoniflorin showed no inhibitory effect on the growth of Lewis lung cancer cells and peritoneal macrophages of mouse in vitro. Paeoniflorin could attenuate the migration of LLC stimulated by alternatively activated macrophages (stimulated for 24 h and 48 h, paeoniflorin 1, 3, 10, 30, 100 μmol·L(-1), P < 0.01 or P < 0.05 vs control group). Paeoniflorin could decrease the cell populations at S phases (paeoniflorin 10, 30, 100 μmol·L(-1), P < 0.05 vs control group) and increase the cell populations at G0-G1 phases of Lewis lung cancer cells (paeoniflorin 100 μmol·L(-1), P < 0.05 vs control group) and reduce the numbers of M2 macrophages in peritoneal macrophages induced by IL-4 (paeoniflorin 1, 3, 10, 30, 100 μmol·L(-1), P < 0.01 vs Control group). Paeoniflorin could reduce lung metastasis of Lewis lung cancer cells xenograft and decrease the numbers of M2 macrophages in subcutaneous xenograft tumour in vivo (paeoniflorin 20, 40 mg·kg(-1), P < 0.01 vs control group). These results suggest that paeoniflorin could reduce lung metastasis of Lewis lung cancer cells xenograft partly through inhibiting the alternative activation of macrophages.
Animals ; Cell Movement ; drug effects ; Cell Proliferation ; drug effects ; Down-Regulation ; drug effects ; Female ; Glucosides ; administration & dosage ; Humans ; Interleukin-4 ; immunology ; Lung Neoplasms ; drug therapy ; immunology ; pathology ; physiopathology ; Macrophages ; cytology ; drug effects ; immunology ; Mice ; Mice, Inbred C57BL ; Monoterpenes ; administration & dosage ; Neoplasm Metastasis ; Paeonia ; chemistry

The present study aimed at investigating the possible effects of β-elemene on the progression of atherosclerosis in a rabbit model. The rabbit atherosclerosis model was established by the combination of balloon angioplasty-induced endothelial injury and an atherogenic diet fed to the rabbits. New Zealand White rabbits were randomly divided into four groups (8/group): the normal control group (fed with normal chow diet), and three experimental groups, placebo group, atorvastatin group, and β-elemene group (received the atherogenic diet). After two weeks on the diet, the three experimental groups underwent balloon injury at right common carotid artery and were treated with drugs or placebo for five weeks. Serum lipids were measured. Carotid artery lesions were isolated for histological and immunohistochemical analysis. In vitro, RAW264.7 macrophages were pretreated with β-elemene and ox-LDL for 24 h and the viability of macrophages was assayed using the MTT method. TNF-α and IL-6 were also determined. Compared with the control group, the thickness of the atherosclerosis lesion in the placebo group was significantly increased; The thickness the drug treatment groups were significantly decreased, compared with that of the placebo group. The infiltration of macrophage was markedly reduced in the β-elemene group compared with that of the placebo group. β-elemene treatment also reduced the levels of TC, TG, and LDL-C, compared with the placebo group. β-elemene decreased the TNF-α and IL-6 levels in vitro. In conclusion, our results demonstrated that β-elemene retarded the progression of atherosclerosis in vivo and in vitro, which may be related to the capacity of β-elemene to reduce the infiltration of macrophages and suppress inflammatory factors.
Animals ; Atherosclerosis ; drug therapy ; genetics ; immunology ; pathology ; Disease Models, Animal ; Disease Progression ; Humans ; Interleukin-6 ; genetics ; immunology ; Macrophages ; immunology ; Male ; Rabbits ; Sesquiterpenes ; administration & dosage ; Tumor Necrosis Factor-alpha ; genetics ; immunology

Xerostomia is a severe side effect of radiation therapy in head and neck cancer patients. To date, no satisfactory treatment option has been established. Because mesenchymal stem cells (MSCs) have been identified as a potential treatment modality, we aimed to evaluate stem cell distribution following intravenous and intraglandular injections using a surgical model of salivary gland damage and to analyse the effects of MSC injections on the recruitment of immune cells. The submandibular gland ducts of rats were surgically ligated. Syngeneic adult MSCs were isolated, immortalised by simian virus 40 (SV40) large T antigen and characterized by flow cytometry. MSCs were injected intravenously and intraglandularly. After 1, 3 and 7 days, the organs of interest were analysed for stem cell recruitment. Inflammation was analysed by immunohistochemical staining. We were able to demonstrate that, after intravenous injection, MSCs were recruited to normal and damaged submandibular glands on days 1, 3 and 7. Unexpectedly, stem cells were recruited to ligated and non-ligated glands in a comparable manner. After intraglandular injection of MSCs into ligated glands, the presence of MSCs, leucocytes and macrophages was enhanced, compared to intravenous injection of stem cells. Our data suggest that injected MSCs were retained within the inflamed glands, could become activated and subsequently recruited leucocytes to the sites of tissue damage.
Animals ; Antigens, Polyomavirus Transforming ; immunology ; Cell Culture Techniques ; Cell Movement ; physiology ; Cell Transformation, Viral ; Clone Cells ; physiology ; Flow Cytometry ; Immunohistochemistry ; Injections, Intralesional ; Injections, Intravenous ; Leukocytes ; pathology ; Macrophages ; pathology ; Mesenchymal Stem Cell Transplantation ; methods ; Mesenchymal Stromal Cells ; pathology ; physiology ; Necrosis ; Rats, Wistar ; Salivary Ducts ; pathology ; Sialadenitis ; pathology ; therapy ; Simian virus 40 ; immunology ; Submandibular Gland ; pathology ; Submandibular Gland Diseases ; pathology ; therapy ; Time Factors

BACKGROUNDHypoxia promotes tumor angiogenesis and hypoxia-inducible factor-1 alpha (HIF-1α) plays a pivotal role in this process. Recently identified pro-angiogenic factor, semaphorin4D (Sema4D) also promotes angiogenesis and enhances invasive proliferation in some tumors. Furthermore, tumor-associated macrophages (TAMs) can increase the expression of HIF-1α and Sema4D in cancer cells and thus influence tumor growth and progression. The purpose of this study was to evaluate the effect of TAMs on the expression of Sema4D and HIF-1α and the impact of biologic behavior in colon cancer cells.

METHODSImmunohistochemistry was used to analyze HIF-1α and Sema4D expression in 86 curatively resected colon cancer samples and 52 normal colon tissues samples. The relationship between their expression and clinicopathological factors was analyzed. Furthermore, macrophage-tumor cell interactions, such as metastasis, angiogenesis, were also studied using in vitro co-culture systems. Statistical analysis was performed using SPSS 17.0 software (SPSS Inc., USA). Differences between two groups were analyzed with Student's t test.

RESULTSHIF-1α (58%) and Sema4D (60%) were expressed at a significantly higher level in tumors than in normal tissues (P < 0.01, for both). Furthermore, HIF-1α and Sema4D expression was significantly correlated with lymphatic metastasis, specific histological types and TNM stages (P < 0.05), but not with age and tumor size (P > 0.05). Sema4D expression was correlated with that of HIF-1α (r = 0.567, P < 0.01). TAMs markedly induced HIF-1α and Sema4D expression in colon cancer cells and subsequently increased their migration and invasion.

CONCLUSIONSHIF-1α and Sema4D expression are closely related to lymphatic metastasis, specific histological types and TNM stages in colon cancer. Furthermore, TAMs promote migration and invasion of colon cancer cells and endothelial tube formation, possibly through up-regulation of HIF-1α and Sema4D.

Adult ; Aged ; Antigens, CD ; genetics ; metabolism ; Cell Line, Tumor ; Colonic Neoplasms ; genetics ; metabolism ; Female ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; genetics ; metabolism ; Immunohistochemistry ; Macrophages ; immunology ; metabolism ; Male ; Middle Aged ; Neoplasm Metastasis ; genetics ; pathology ; Semaphorins ; genetics ; metabolism

Toxoplasma gondii is an intracellular protozoan parasite that causes a Th1 cellular immunity. Our previous study showed that T. gondii lysate antigen (TLA) treatment in S180 tumor-bearing mice resulted in tumor reduction by suppressing CD31 expression, a marker of angiogenesis. In the present study, to investigate tumor suppressive effect of TLA under the absence of T lymphocytes, athymic nude mice were compared with euthymic mice in the anti-tumorigenic effect triggered by TLA in CT26 tumors. According to the results, intratumorally injected TLA reduced tumor growth and TIMP-1 level, a metastatic marker, in both euthymic and athymic mice. TLA treatment led to a sharp increase in IL-12 expression in serum cytokine profiling of athymic mice, and increased MyD88 signals in macrophages derived from the bone marrow, implying the activation of innate immunity. The selective induction of IL-12 by TLA treatment had an anti-tumorigenic effect.
Animals ; Antigens, Protozoan/*immunology ; Disease Models, Animal ; Immunity, Innate ; Immunotherapy/*methods ; Interleukin-12/*blood ; Macrophages/immunology ; Mice, Inbred BALB C ; Mice, Nude ; Myeloid Differentiation Factor 88/analysis ; Neoplasms/pathology/*therapy ; Toxoplasma/*immunology ; Treatment Outcome