• Journal of Radiopharmaceuticals and Molecular Probes
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• v.7 no.1
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• pp.41-49
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• 2021

Diversity and flexibility are two typical hallmarks of macrophages. Two types of macrophages, M1(classically activated macrophages) and M2(alternatively activated macrophages) exist at both ends of the commonly known macrophage polarization. M1 macrophages have inflammatory properties and are primarily responsible for defending against invading bacteria in our body. On the other hand, M2 macrophages are involved in anti-inflammatory responses and tissue remodeling. Polarized migration of macrophages is of increasing interest in regulating the initiation, generation, and resting phases of inflammatory diseases. In this review, it intend to discuss the properties and functions of tumor-associated macrophages based on polarized macrophages that affect inflammatory diseases. In addition, the purpose of this study is to investigate a molecular imaging approach that targets macrophages that affect tumor growth by controlling the polarization of macrophages that affect tumor diagnosis and treatment.

• Advances in Traditional Medicine
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• v.4 no.1
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• pp.9-17
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• 2004

The present investigation was under taken to study whether the tumor-associated macrophages (TAM) of Daltons lymphoma (DL), a spontaneous transplantable murine T cell lymphoma can be activated to tumoricidal state by crude thymus extract. Intraperitoneal administration of thymus extract to DL-bearing mice resulted in activation of TAM with an enhanced IL-1, TNF and antigen presenting ability. It was found that treatment with thymus extract could also enhance the phagocytic and cytotoxic activity of TAM. However, only a marginal increase in arginase activity was observed. Till date to the best of our knowledge the effect of crude thymus extract on the activation of tumor associated macrophages has not been investigated, this study provides a new piece of information in the area of thymus therapy.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.5 no.2
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• pp.113-119
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• 2019

During tumor progression various immunosuppressive cells are recruited to a tumor microenvironment (TME). Tumor-associated macrophages (TAMs) are particularly abundant in TME. Based on their function, macrophages are categorized into two phenotypes: tumoricidal M1 and tumor-supportive M2. Generally, TAMs closely resemble M2-macrophages and lead to tumor growth. However, their phenotype can be changed by immune activator from M2 to M1 and thus promote tumor immunotherapy. Ginseng extracts are well known for its anti-tumor and anti-inflammatory effects from numerous reported studies. However, the mechanism of their effects is still not clear. Recently, some studies suggested that ginseng extracts induced immune activation as well as anti-tumor activities by a repolarization of activated macrophage from M2 phenotype to M1 phenotype. But, further verification about the mechanism as to how ginseng extracts can stimulate the immune response is still needed. In this study, we investigated whether ginseng extracts can alter the phenotype from M2 macrophages to M1 macrophages in mice by using a radiolabeled liposome. And we also evaluated the potential of radiolabeled liposome as a nuclear imaging agent to monitor the transition of phenotype of TAMs. In conclusion, the ginseng extracts seem to change the phenotype of macrophages from M2 to M1 like as lipopolysaccharide (LPS) in mice.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.7
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• pp.3043-3050
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• 2015

The tumor microenvironment (TME) includes numerous non-neoplastic cells such as leukocytes and fibroblasts that surround the neoplasm and influence its growth. Tumor-associated macrophages (TAMs) and cancerassociated fibroblasts (CAFs) are documented as key players in facilitating cancer appearance and progression. Alteration of the macrophage (CD68, CD163) and fibroblast (${\alpha}-SMA$, FSP-1) cells in Opisthorchis viverrini (Ov) -induced cholangiocarcinoma (CCA) was here assessed using liver tissues from an established hamster model and from 43 human cases using immunohistochemistry. We further investigated whether M2-activated TAMs influence CCA cell migration ability by wound healing assay and Western blot analysis. Macrophages and fibroblasts change their phenotypes to M2-TAMs (CD68+, CD163+) and CAFs (${\alpha}-SMA+$, FSP-1+), respectively in the early stages of carcinogenesis. Interestingly, a high density of the M2-TAMs CCA in patients is significantly associated with the presence of extrahepatic metastases (p=0.021). Similarly, CD163+ CCA cells are correlated with metastases (p=0.002), and they may be representative of an epithelial-to-mesenchymal transition (EMT) with increased metastatic activity. We further showed that M2-TAM conditioned medium can induce CCA cell migration as well as increase N-cadherin expression (mesenchymal marker). The present work revealed that significant TME changes occur at an early stage of Ov-induced carcinogenesis and that M2-TAMs are key factors contributing to CCA metastasis, possibly via EMT processes.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.3
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• pp.209-215
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• 2006

Preoperative neoadjuvant chemotherapy using cisplatin and 5-FU is generally given in oral and maxillofacial cancer. At tissue level both inflammation and fibrosis occur after chemotherapy. The cellular changes mimic those of a granulating wound, with activated macrophages and fibroblasts replacing the malignant cells as they are erradicated. Stromal cells, together with extracellular matrix components, provide the microenvironment that is pivotal for tumor cell growth, invasion, and metastatic progression. Vascular endothelial growth factor(VEGF), an important regulator of angiogenesis in cancer, induces mitogenesis of vascular endothelial cells, and vascular permeabilization and microvessel formation in a tumor are associated with tumor nutrition and oxygenation. Also, they are associated with chemotherapeutic drug delivery. Oxygen delivery to tumor appears to rely on a network of microvessels, On the other hand, the tumor microvessel is clearly an important factor in chemotherapeutic drug delivery to cancer cells, and the efficacy of drug delivery can be high in richly vascularized tumors. So, this study was conducted to evaluate the effect of neoadjuvant chemotherapy on microvessel density from 11 patients with tongue cancers. Our results showed that neoadjuvant chemotherapy was seemed to decrease VEGF expression in tumor cells, however, it did not significantly alter VEGF expression in tumor-associated macrophages. Also, Neoadjuvant chemotherapy had little effect on the microvessel density using CD34, and tumor-associated macrophage level using CD68. Thus, tumorassociated macrophages seem to be the key factor associated with the maintenance of microvessel density after neoadjuvant chemotherapy in tongue cancer.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.1
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• pp.11-19
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• 2007

This study was to evaluate the expression of vascular endothelial growth factor receptors (VEGFRs) in tumor and stromal cells of tougue squamous cell carcinoma (SCC). We also wanted to characterize the differences, from the angiogenic aspect, between cancer-associated stromal cells and non-malignant stromal cells. Paraffin-embedded tumor specimens from eleven patients with tongue SCCs were studied. Immunohistochemical staining for VEGFR-1,-2, and -3 was performed on the tumor cells, stromal fibroblasts and tumor-associated macrophages of the specimens. The expression of all 3 receptors was detected in the tumor cells themselves of the biopsy specimens. All 3 receptors were also expressed on stromal cells, except that VEGFR-2 was not expressed in stromal fibroblasts. In radical excision specimens, the staining intensity for VEGFR-1, -2 in the tumor cells and VEGFR-1,-3 in the tumor-associated macrophages was significantly lower than that in the biopsy specimens (P < 0.05). By using the general marker of fibroblast and macrophage, 5B5 and CD68, respectively, we performed double immunofluorescence staining for 5B5 and each VEGFR in the stromal fibroblasts and for CD68 and each VEGFR in the tumor-associated macrophages of the radical excision specimens. We used 4 cases of fibroma and 4 cases of chronic inflammation tissue as the controls. It was found that only each marker was expressed in the control group, however, 5B5/VEGFR-1 and 5B5/VEGFR-3 in the stromal fibroblasts, and CD68/VEGFR-1 and CD68/VEGFR-3 in the tumor-associated macrophages were double stained in the radical excision specimens. Although our study used small number of specimens, the results of our study showed that in tongue SCC, in association with the angiogenesis, the stromal cells showed the activated phenotype and this was different from the nonmalignant stromal cells.

• BMB Reports
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• v.55 no.2
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• pp.81-86
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• 2022

Macrophages are a major cellular component of innate immunity and are mainly known to have phagocytic activity. In the tumor microenvironment (TME), they can be differentiated into tumor-associated macrophages (TAMs). As the most abundant immune cells in the TME, TAMs promote tumor progression by enhancing angiogenesis, suppressing T cells and increasing immunosuppressive cytokine production. N-myc downstream-regulated gene 2 (NDRG2) is a tumor suppressor gene, whose expression is down-regulated in various cancers. However, the effect of NDRG2 on the differentiation of macrophages into TAMs in breast cancer remains elusive. In this study, we investigated the effect of NDRG2 expression in breast cancer cells on the differentiation of macrophages into TAMs. Compared to tumor cell-conditioned medium (TCCM) from 4T1-mock cells, TCCM from NDRG2-over-expressing 4T1 mouse breast cancer cells did not significantly change the morphology of RAW 264.7 cells. However, TCCM from 4T1-NDRG2 cells reduced the mRNA levels of TAM-related genes, including MR1, IL-10, ARG1 and iNOS, in RAW 264.7 cells. In addition, TCCM from 4T1-NDRG2 cells reduced the expression of TAM-related surface markers, such as CD206, in peritoneal macrophages (PEM). The mRNA expression of TAM-related genes, including IL-10, YM1, FIZZ1, MR1, ARG1 and iNOS, was also downregulated by TCCM from 4T1-NDRG2 cells. Remarkably, TCCM from 4T1-NDRG2 cells reduced the expression of PD-L1 and Fra-1 as well as the production of GM-CSF, IL-10 and ROS, leading to the attenuation of T cell-inhibitory activity of PEM. These data showed that compared with TCCM from 4T1-mock cells, TCCM from 4T1-NDRG2 cells suppressed the TAM differentiation and activation. Collectively, these results suggest that NDRG2 expression in breast cancer may reduce the differentiation of macrophages into TAMs in the TME.

• Advances in Traditional Medicine
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• v.3 no.2
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• pp.72-79
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• 2003

The present investigation was undertaken to study whether tumor-associated macrophages of Daltons lymphoma (DL), a spontaneous transplantable T cell lymphoma can be activated to tumoricidal state by alcoholic extract of Tinospora cordifolia (ALTC). In vivo administration of ALTC (200 mg/kg body weight) in DL-bearing mice resulted in an enhanced RNI production and an augmented cytotoxic response of tumor-associated macrophages. Earlier we had reported that DL-bearing mice show a regression of thymus and an enlargement of spleen. In vivo administration of ALTC to DL-bearing hosts resulted in a decrease in the weight of spleen and counts of splenocytes along with an increase in the weight of thymus as compared to control DL-bearing mice. In vivo administration of ALTC in DL-bearing mice also resulted in an increase in the proliferation of splenocytes/thymocytes and BMC. The results of this study indicate that the ALTC upon in vivo administration in DL-bearing shows immuno-modulatory effects and thus may have clinical significance.

• Advances in Traditional Medicine
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• v.7 no.5
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• pp.459-465
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• 2008

The present study was undertaken to investigate the effect of in vivo administration of neem oil intra-peritoneally (i.p.) to mice bearing a progressively growing transplantable T cell lymphoma of spontaneous origin, designated as Daltons lymphoma (DL), on the tumor growth. Mice were administered various doses of neem oil mixed in groundnut oil, which was used as a diluting vehicle or for administration to control DL-bearing mice. Administration of neem oil resulted in an acceleration of tumor growth along with a reduction in the survival time of the tumor-bearing host. Neem oil administered DL-bearing mice showed an augmented apoptosis in splenocytes, bone marrow cells and thymocytes along with an inhibition in the anti-tumor functions of tumor-associated macrophages. Thus this study gives an altogether a novel information that neem oil instead of the popular belief of being anti-tumor and immunoaugmentary may in some tumor-bearing conditions, behave in an opposite way leading to an accelarated tumor progression along with a collapse of the host's anti-tumor machinery. These observations will thus have long lasting clinical significance, suggesting caution in use of neem oil for treatment of cancer.

• Journal of Life Science
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• v.28 no.8
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• pp.992-998
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• 2018

Cancer cells grow in an environment composed of various components that supports tumor growth. Major cell types in the tumor microenvironment are fibroblast, endothelial cells and immune cells. All of these cells communicate with cancer cells. Among infiltrating immune cells as an abundant component of solid tumors, macrophages are a major component of the tumor microenvironment and orchestrates various aspects of immunity. The complex balance between pro-tumoral and anti-tumoral effects of immune cell infiltration can create a chronic inflammatory microenvironment essential for tumor growth and progression. Macrophages express different functional programs in response to microenvironmental signals, defined as M1 and M2 polarization. Tumor-associated macrophages (TAM) secret many cytokines, chemokines and proteases, which also promote tumor angiogenesis, growth, metastasis and immunosuppression. TAM have multifaceted roles in the development of many tumor types. TAM also interact with cancer stem cells. This interaction leads to tumorigenesis, metastasis, and drug resistance. TAM obtain various immunosuppressive functions to maintain the tumor microenvironment. TAM are characterized by their heterogeneity and plasticity, as they can be functionally reprogrammed to polarized phenotypes by exposure to cancer-related factors, stromal factors, infections, or even drug interventions. Because TAMs produce tumor-specific chemokines by the stimulation of stromal factors, chemokines might serve as biomarkers that reflect disease activity. The evidence has shown that cancer tissues with high infiltration of TAM are associated with poor patient prognosis and resistance to therapies. Targeting of TAM in tumors is considered a promising therapeutic strategy for anti-cancer treatment.