Safety and adverse effects of the coronavirus disease 2019 vaccine among the general Japanese adult population.

OBJECTIVES: We aimed to identify and explore the association between the characteristics of coronavirus disease 2019 (COVID-19) vaccine recipients and the types of vaccine-related adverse effects in the general Japanese adult population. METHODS: An anonymous self-report questionnaire was distributed to 4393 students and 1657 white and blue-collar workers (N = 6050). Data on vaccine-related adverse effects were collected twice, once after each vaccination. The data collection was performed daily from the day of injection (D0) until the sixth day after injection (D6). The list of adverse effects comprised local reactions at the injection site (pain, redness, and swelling) and systemic symptoms (fever, fatigue, headache, myalgia, joint pain, chills, and nausea or vomiting). The Student's t-test and Mann-Whitney U test were used to analyze parametric and non-parametric data, respectively. RESULTS: The incidence of adverse reactions to the COVID-19 vaccination was higher after the second dose (e.g., redness: 47.1%; swelling: 60.6%; fever: 80.6%) of vaccination than after the first dose (e.g., redness: 16.4%; swelling: 37.2%; fever: 11.9%). Women reported adverse reactions to the vaccination more frequently. Some adverse reactions included more symptoms in younger participants, and participants with a lower body mass index were more at risk for these symptoms. CONCLUSIONS: Some adverse reactions to the COVID-19 vaccination are a greater risk of symptoms in the younger group, women, and participants with lower BMI. Care should be taken to monitor women, younger people, and individuals with a low body mass index for adverse effects after receiving the COVID-19 vaccination.

Blocking cholesterol efflux mechanism is a potential target for antilymphoma therapy.

Cholesterol is an essential plasma membrane lipid for the maintenance of cellular homeostasis and cancer cell proliferation. Free cholesterol is harmful to cells; therefore, excessive free cholesterol must be quickly esterified by acetyl-coenzyme A:cholesterol acetyltransferase (ACAT) and exported by scavenger receptor class B member I (SR-BI) or ATP-binding cassette protein A1 from specific cells such as macrophage foam cells, which contain cholesteryl ester-derived vacuoles. Many vacuoles are present in the cytoplasm of Burkitt lymphoma cells. In this study, we observed that these vacuoles are often seen in high-grade lymphomas. Cell culture study using lymphoma cell lines found that esterified cholesterol is the main component of these vacuoles and the expression of cholesterol metabolism-related molecules was significantly upregulated in lymphoma cell lines, with SR-BI and ACAT inhibitors (BLT-1 and CI-976, respectively) impeding lymphoma cell proliferation. Cytoplasmic free cholesterol was increased by ACAT and SR-BI inhibitors, and the accumulation of free cholesterol induced lymphoma cell apoptosis by inducing endoplasmic reticulum stress. Furthermore, synergistic effects of SR-BI and ACAT inhibitors were observed in a preclinical study. Treatment with SR-BI inhibitor suppressed lymphoma progression in a tumor-bearing mouse model, whereas ACAT inhibitor did not. Therefore, SR-BI inhibitors are potential new antilymphoma therapeutics that target cholesterol metabolism.

Cyclic sulfur compounds targeting macrophage polarization into M2/protumor phenotype and their anti-tumor effects.

Tumor-associated macrophages (TAMs), especially the M2-like phenotype, promote tumor progression, making them candidate targets for anti-tumor therapy. We previously discovered a cyclic sulfur compound, Onionin A (ONA), which suppresses tumor progression by inhibiting the M2-polarization of TAMs. In the present study, we sought to find new candidate compounds possessing a stronger effect compared to ONA by exploring compounds with structures similar to those of ONA among several cyclic sulfur compounds. A total of 81 cyclic sulfur compounds were screened, and their effects on macrophage polarization toward an M2-like phenotype were tested using human monocyte-derived macrophages (HMDMs). The anti-tumor effects of the identified candidate compounds were examined in a tumor-bearing mouse model. Three candidate compounds inhibited both IL-10- and tumor culture supernatant (TCS)-induced M2-polarization of HMDMs. These compounds also suppressed STAT3 activation in HMDMs stimulated by IL-10 and TCS, whereas these compounds had no effect on STAT3 activation in tumor cells. Furthermore, these compounds inhibited tumor cell proliferation under co-culture conditions with HMDMs, indicating that the three candidate compounds suppress tumor proliferation by regulating cell-cell interactions between tumor cells and macrophages. In addition, two of these candidate compounds had inhibitory effects on tumor growth and lung metastasis in the LM8 tumor-bearing mouse model. Our study identified new candidate cyclic sulfur compounds for anti-tumor therapy targeting the M2-polarization of TAMs.

CD163 deficiency facilitates lipopolysaccharide-induced inflammatory responses and endotoxin shock in mice.

OBJECTIVES: Septic (or endotoxin) shock is a severe systemic inflammatory disease caused by bacteraemia or endotoxaemia. Although it is known that increased serum levels of CD163 are observed in septic/endotoxin shock patients, the exact function and significance of CD163 in macrophage activation remain unclear. Therefore, in the current study, we tested whether CD163 contributes to the pathogenesis of endotoxin shock in mice. METHODS AND RESULTS: In samples obtained from autopsy, the number of CD163-positive macrophages was increased in the kidney, liver, heart, bone marrow and spleen of patients who had died from septic/endotoxin shock when compared to patients who had died from other causes. The animal study revealed a significantly lower survival rate in CD163-deficient mice after lipopolysaccharide (LPS) injection. Several cytokines and oxidative stress-related molecules were significantly elevated in the sera of LPS-induced endotoxin shock mice models. Higher concentrations of IL-6, TNF-α, IL-1ß, nitrite ( NO 2 - ) and nitrate ( NO 3 - ) and a lower concentration of IL-10 were observed in CD163-deficient mice treated with LPS. Similar results were observed in CD163-deficient LPS-stimulated macrophages. Furthermore, in an antitype II collagen antibody-induced arthritis (CAIA), rheumatoid arthritis model, inflammation and bone erosion scores as well as the expression of IL-6 and IL-1ß were significantly increased in CD163-deficient mice. CONCLUSIONS: CD163 was suggested to be involved in the regulation of inflammatory cytokine expression in septic/endotoxin shock and CAIA.

Flavonoid Compounds Contained in Epimedii Herba Inhibit Tumor Progression by Suppressing STAT3 Activation in the Tumor Microenvironment.

M2-like tumor-associated macrophages (TAMs) in the tumor tissues promote tumor progression by various mechanisms and represent possible targets of antitumor therapy. In the present study, we tested whether compounds from Epimedii Herba inhibit macrophage polarization to the M2/protumorigenic phenotype and prevent tumor progression, using human monocyte-derived macrophages (HMDMs) and an animal sarcoma model. Four Epimedii Herba-derived flavonoid compounds, namely, limonianin, epimedokoreanin B, icaritin, and desmethylicaritin, inhibited CD163 expression and interleukin (IL)-10 production, which are known M2 markers, suggesting that these compounds inhibit M2 polarization. Among these compounds, epimedokoreanin B and limonianin suppressed STAT3 activation in HMDMs. Notably, epimedokoreanin B also suppressed cell proliferation by blocking STAT3 activation in Saos-2 human sarcoma and LM8 mouse sarcoma cell lines. Furthermore, oral administration of epimedokoreanin B inhibited tumor growth in an LM8 tumor-bearing murine model. These results indicate that Epimedii Herba and Epimedii Herba-derived compounds, such as epimedokoreanin B, may be potentially new agents that can be used for the treatment and prevention of various malignant tumors. They may also be promising compounds for targeting the tumor microenvironment by inhibiting M2 polarization of the TAMs.

CD163 Is Required for Protumoral Activation of Macrophages in Human and Murine Sarcoma.

Recent findings have shown the significance of CD163-positive macrophages in tumor progression, yet there have been few studies on the function of CD163 in macrophages. Here, we uncover the role of CD163 in macrophage activation using CD163-deficient mice and human samples. We detected CD163 in 62 undifferentiated pleomorphic sarcoma samples, in which a high percentage of CD163-positive macrophages was associated with decreased overall survival and higher histologic grade. We observed macrophage-induced tumor cell proliferation in cocultures of human monocyte-derived macrophages and leiomyosarcoma (TYLMS-1) and myxofibrosarcoma (NMFH-1) cell lines, which was abrogated by silencing of CD163. Tumor development of sarcoma (MCA205 and LM8) cells in CD163-deficient mice was significantly abrogated in comparison with wild-type (WT) mice. Coculture with WT peritoneal macrophages significantly increased proliferation of MCA205 cells but decreased in the presence of CD163-deficient macrophages. Production of IL6 and CXCL2 in CD163-deficient macrophages was suppressed in comparison with WT macrophages, and overexpression of CD163 in CD163-deficient macrophages induced production of IL6 and CXCL2. Silencing of IL6 but not CXCL2 abrogated macrophage-induced proliferation of MCA205 cells. Taken together, our results show that CD163 is involved in protumoral activation of macrophages and subsequent development and progression of tumors in mice and humans.Significance: Macrophage CD163-mediated induction of IL6 promotes tumor development and progression in murine and human malignant tumors. Cancer Res; 78(12); 3255-66. ©2018 AACR.

CD163-positive cancer cells are potentially associated with high malignant potential in clear cell renal cell carcinoma.

CD163 is preferentially expressed by monocyte/macrophages; however, recent studies using immunohistochemistry (IHC) have reported that some cancer cells also express CD163. In the present IHC study, we investigated CD163 staining of cancer cells and macrophages in clear cell renal cell carcinoma (ccRCC) tissues and determined the relationship between cancer cell CD163 expression and clinical prognosis in patients with ccRCC. IHC for CD163 was performed in ccRCC tissues from 103 patients. CD163-positive cancer cells were detected in 35% of the patients (36/103); however, the positive signals on cancer cells were significantly lower than those on macrophages. CD163-positive cancer cells were preferentially detected in patients with high T classification, and females, and were significantly associated with shortened progression-free survival and a lower overall survival ratio. Notably, a high intensity of CD163-positive macrophage infiltration was detected in the CD163-positive cancer cell-high tumor areas. Although CD163 mRNA was detected in cultured macrophages, no CD163 mRNA was detected in two cultured RCC cell lines. The detailed mechanism by which a positive signal is detected on cancer cells has not been clarified. Detection of the CD163 antigen on cancer cells might be a useful marker for evaluating the clinical course of patients with ccRCC.

Selective depletion of cultured macrophages by magnetite nanoparticles modified with gelatin.

Previous studies have indicated pro-tumor functions of macrophages in tumor progression in different types of malignant tumors. The detailed mechanisms of cell-cell interaction between macrophages and tumor cells have been investigated by means of in vitro co-culture experiments. The present study developed magnetite nanoparticles modified with gelatin that are specifically engulfed by macrophages and investigated methods to deplete these macrophages in co-culture experiments using a magnet. T98G glioma cell line and human monocyte-derived macrophages were mixed and co-cultured for 2 days. The T98G cells were isolated by depletion of the macrophages using the magnetite nanoparticles. mRNA expression of a number of pro-tumor molecules in the isolated T98G cells, with or without co-culture with macrophages, was then evaluated. The mRNA expression levels of chemokine (CC motif) ligand 2, interleukin-6 and macrophage-colony stimulating factor receptor (M-CSFR) were significantly upregulated in T98G cells by co-culture with macrophages (P<0.01). M-CSFR protein expression was also increased by co-culture with macrophages. The conditioned medium of co-cultured cells increased M-CSFR expression in T98G cells. Magnetite nanoparticles may be a novel tool not only for investigating the unique activation status of tumor cells in co-culture conditions, but also for targeting pro-tumor macrophages in tumor tissues.

Optimum immunohistochemical procedures for analysis of macrophages in human and mouse formalin fixed paraffin-embedded tissue samples.

Macrophages are closely related to various diseases and it is therefore important that the properties of macrophages are adequately evaluated in human diseases and mouse disease models. Immunohistochemistry (IHC) of formalin fixed paraffin-embedded (FFPE) samples is a very useful tool for examination of macrophages; however, an adequate IHC protocol is required for the examination of macrophage states. In this study, we assessed various antigen retrieval methods in order to devise the optimal protocols for staining of macrophages with a range of antibodies. Optimum combinations of primary antibodies and antigen retrieval protocols were determined; for example, heat treatment with ethylenediamine tetraacetic acid solution, pH 8.0, was the best procedure for IHC using mouse anti-Iba1 and human anti-CD11b, -CD163, -CD169, -CD204, and -CD206 antibodies. Moreover, we found that the immunoreactivity of sliced tissue sections decreased gradually over time in long term storage but that this immunoreactivity was preserved in storage at -80 °C in a deep freezer. The optimal IHC protocols and storage procedures that were determined in this study should be a useful tool for macrophage research.

High density of CD204-positive macrophages predicts worse clinical prognosis in patients with breast cancer.

Recent studies have indicated the clinical significance of tumor-associated macrophages (TAM) in several malignant tumors including breast cancer. Although recent studies have focused on CD68-positive or CD163-positive TAM in breast cancer, no study has investigated the significance of CD204-positive TAM in breast cancer. We found that CD204 expression on macrophages was evaluated following stimulation with the conditioned medium (CM) of breast cancer cell lines. Paraffin sections of 149 breast cancer samples which were diagnosed as invasive ductal carcinoma were immunohistochemically analyzed for CD68, CD163 and CD204 expression. The results of analyses indicated that a high number of CD204-positive TAM was associated with worse clinical prognoses, including relapse-free survival, distant relapse-free survival and breast cancer-specific survival; however, neither the numbers of CD68-positive or CD163-positive TAM were associated with clinical courses. Of the clinicopathological factors investigated, estrogen receptor, Ki-67 index, hormone subtype, and histological grade were significantly related to the increased number of CD163-positive and CD204-positive TAM. These data indicate the clinical significance of CD204-positive TAM in breast cancer progression and CD204 is a marker for predicting clinical prognosis in breast cancer.

Stat3 inhibitor abrogates the expression of PD-1 ligands on lymphoma cell lines.

Recent studies have indicated the significance of immune checkpoint molecules including programmed death-1 (PD-1), cytotoxic T-lymphocyte associated protein 4, and T-cell immunoglobulin and mucin domain-containing molecule-3 for anti-tumor immune responses. We previously investigated PD-1 ligand 1/2 (PD-L1/2) expression in lymphoma cell lines, and found that PD-L1/2 is expressed on the adult T-cell leukemia/lymphoma (ATL-T) and B-cell lymphoma (SLVL) cell lines. In the present study, we investigated whether the Stat3 inhibitor WP1066 abrogated PD-L1/2 expression in lymphoma cell lines. Incubation with WP1066 inhibited lymphoma cell growth and induced cell apoptosis. PD-L1/2 expression in the ATL-T, SLVL, and human brain malignant lymphoma (HKBML) cell lines was significantly abrogated by WP1066 treatment. These data indicated that a Stat3 inhibitor abrogated PD-L1/2 expression in lymphoma cells. Such an inhibitor is therefore considered to be useful for additional immunotherapy in patients with advanced lymphoma.

Cell adhesion molecule-1 (CADM1) expressed on adult T-cell leukemia/lymphoma cells is not involved in the interaction with macrophages.

Cell adhesion molecule 1 (CADM1) is a cell adhesion molecule that is expressed in brain, liver, lung, testis, and some kinds of cancer cells including adult T-cell leukemia/lymphoma (ATLL). Recent studies have indicated the involvement of CADM1 in cell-cell contact between cytotoxic T-lymphocytes and virus infected cells. We previously reported that cell-cell interaction between lymphoma cells and macrophages induces lymphoma cell proliferation. In the present study, we investigated whether CADM1 is associated with cell-cell interaction between several human lymphoma cell lines and macrophages.CADM1 expression was observed in the ATLL cell lines, ATN-1, ATL-T, and ATL-35T, and in the B cell lymphoma cell lines, TL-1, DAUDI, and SLVL, using western blotting. Significant cell-cell interaction between macrophages and ATN-1, ATL-T, ATL-35T and MT-2, DAUDI, and SLVL cells, as assessed by induction of cell proliferation, was observed. Immunohistochemical analysis of human biopsy samples indicated CADM1 expression in 10 of 14 ATLL cases; however, no case of follicular lymphoma or diffuse large B-cell lymphoma was positive for CADM1. Finally, the interaction of macrophages with cells of the CADM1-negative ED ATLL cell line and CADM1-transfected ED cells was tested. However, significant cell-cell interaction between macrophage and CADM1-transfected ED cells was not observed. We conclude that CADM1 was not associated with cell-cell interaction between lymphoma cells and macrophages, although CADM1 may be a useful marker of ATLL for diagnostic procedures.

The cell-cell interaction between tumor-associated macrophages and small cell lung cancer cells is involved in tumor progression via STAT3 activation.

OBJECTIVES: Small cell lung cancer (SCLC) is an aggressive tumor with a poor prognosis. It is well known that various stromal cells, including macrophages, play a role in tumor progression in several types of malignant tumors; however, the significance of tumor-associated macrophages (TAMs) in SCLC has not been fully elucidated. Signal transducer and activator of transcription 3 (STAT3) is a molecule well-known to be related to tumor progression. In the present study, we investigated the relationship of TAMs and SCLC cells to test the hypothesis that TAMs induce tumor progression in SCLC via STAT3 activation. MATERIALS AND METHODS: We performed immunohistochemical analysis using surgically resected tumor specimens and in vitro co-culture experiments using human SCLC cell lines and human monocyte-derived macrophages. RESULTS: We first demonstrated via immunostaining that STAT3 activation in tumor cells was predominantly observed in the peripheral areas of tumor nests existing near TAMs in stroma. The indirect co-culture of SCLC cells and macrophages induced STAT3 activation in both cell types, and macrophage-derived culture supernatant (CS) significantly activated STAT3 in SCLC cells. Macrophage-derived CS induced tumor cell proliferation and invasion via STAT3 activation. In addition, chemo-resistance and sphere formation were also increased by macrophage-derived CS. Macrophage-derived interleukin-6 and CC chemokine ligand 4 (CCL4/MIP-1ß) were suggested to be associated with STAT3 activation in SCLC cells. CS-induced STAT3 activation in SCLC cells was suppressed by anti-IL-6 receptor antibody, but not by anti-CCL4/MIP-1ß antibody. CONCLUSION: These results suggest that TAMs are likely involved in SCLC progression via STAT3 activation and TAM-derived IL-6 is indicated to be one of molecules related to STAT3 activation in SCLC cells. Thus, the cell-cell interaction between TAMs and SCLC cells might be a target for therapy.

An IL-27/Stat3 axis induces expression of programmed cell death 1 ligands (PD-L1/2) on infiltrating macrophages in lymphoma.

Immune escape and tolerance in the tumor microenvironment are closely involved in tumor progression, and are caused by T-cell exhaustion and mediated by the inhibitory signaling of immune checkpoint molecules including programmed death-1 (PD-1), cytotoxic T-lymphocyte associated protein 4, and T-cell immunoglobulin and mucin domaincontaining molecule-3. In the present study, we investigated the expression of the PD-1 ligand 1 (PD-L1) in a lymphoma microenvironment using paraffin-embedded tissue samples, and subsequently studied the detailed mechanism of upregulation of PD-L1 on macrophages using cultured human macrophages and lymphoma cell lines. We found that macrophages in lymphoma tissues of almost all cases of adult T-cell leukemia/lymphoma (ATLL), follicular lymphoma and diffuse large B-cell lymphoma expressed PD-L1. Cell culture studies showed that the conditioned medium of ATL-T and SLVL cell lines induced increased expression of PD-L1/2 on macrophages, and that this PD-L1/2 overexpression was dependent on activation of signal transducer and activator of transcription 3 (Stat3). In vitro studies including cytokine array analysis showed that IL-27 (heterodimer of p28 and EBI3) induced overexpression of PD-L1/2 on macrophages via Stat3 activation. Because lymphoma cell lines produced IL-27B (EBI3) but not IL-27p28, it was proposed that the IL-27p28 derived from macrophages and the IL-27B (EBI3) derived from lymphoma cells formed an IL-27 (heterodimer) that induced PD-L1/2 overexpression. Although the significance of PD-L1/2 expressions on macrophages in lymphoma progression has never been clarified, an IL-27-Stat3 axis might be a target for immunotherapy for lymphoma patients.

Onionin A inhibits ovarian cancer progression by suppressing cancer cell proliferation and the protumour function of macrophages.

It is well known that tumour-associated macrophages (TAMs) play an important role in tumour development by modulating the tumour microenvironment, and targeting of protumour activation or the M2 polarization of TAMs is expected to be an effective therapy for cancer patients. We previously demonstrated that onionin A (ONA), a natural low molecular weight compound isolated from onions, has an inhibitory effect on M2 macrophage polarization. In the present study, we investigated whether ONA had a therapeutic anti-ovarian cancer effect using in vitro and in vivo studies. We found that ONA reduced the extent of ovarian cancer cell proliferation induced by co-culture with human macrophages. In addition, we also found that ONA directly suppressed cancer cell proliferation. A combinatorial effect with ONA and anti-cancer drugs was also observed. The activation of signal transducer and activator of transcription 3 (STAT3), which is involved in cell proliferation and chemo-resistance, was significantly abrogated by ONA in ovarian cancer cells. Furthermore, the administration of ONA suppressed cancer progression and prolonged the survival time in a murine ovarian cancer model under single and combined treatment conditions. Thus, ONA is considered useful for the additional treatment of patients with ovarian cancer owing to its suppression of the protumour activation of TAMs and direct cytotoxicity against cancer cells.

Onionin A, a sulfur-containing compound isolated from onions, impairs tumor development and lung metastasis by inhibiting the protumoral and immunosuppressive functions of myeloid cells.

SCOPE: Recent studies have demonstrated that myeloid lineage cells, such as macrophages and myeloid suppressor cells (MDSCs), are major components exhibiting protumoral functions in the setting of tumor progression. Tumor-associated macrophages polarized to the protumoral M2 phenotype promote tumor proliferation and are considered to be a therapeutic target in patients with malignant tumors. METHODS AND RESULTS: We identified a new candidate compound, called onionin A (ONA) isolated from onions, that inhibits macrophage polarization into the M2 phenotype, as well as the immunosuppressive activity of MDSCs and tumor proliferation, by suppressing signal transducer and activator of transcription-3 (Stat3) activation. Furthermore, ONA administration was found to significantly suppress subcutaneous tumor development and lung metastasis in tumor-bearing mice. ONA administration also inhibited Stat3 activation and increased the number of infiltrating lymphocytes in tumor tissues, and an ex vivo analysis showed that the immunosuppressive effect of MDSCs in tumor-bearing mice is impaired by ONA. Moreover, ONA regulated tumor proliferation by inhibiting cell-cell interactions between macrophages and tumor cells, and ONA administration enhanced the antitumor effects of cisplatin in the tumor-bearing mice. CONCLUSIONS: These findings demonstrate that ONA may be a potential new tool for antitumor therapy and also for tumor prevention.

TIM-3 expression in lymphoma cells predicts chemoresistance in patients with adult T-cell leukemia/lymphoma.

Adult T-cell leukemia/lymphoma (ATLL), an aggressive type of malignant lymphoma, is highly resistant to chemotherapy. However, the detailed mechanisms of the chemoresistance of ATLL have never been elucidated. We previously demonstrated that direct cell-cell interaction between macrophages and lymphoma cells was significantly associated with lymphoma progression in patients with ATLL. The present study aimed to further analyze the effects of cell-cell interaction between macrophages and ATLL cells by means of cell culture studies and immunohistochemical analysis using human ATLL samples. It was found that direct co-culture with macrophages induced chemoresistance in the ATLL ATN-1 cell line, but not in other cell lines, including TL-Mor, ED and ATL-2S. It was also found that expression of the T cell Ig and mucin domain-containing molecule-3 (TIM-3) was induced in ATN-1 cells by their long-term co-culture with macrophages. TIM-3 gene transfection induced chemoresistance in the ATN-1 cells. Immunostaining of ATLL tissues showed TIM-3 expression in 25 out of 58 ATLL cases. Although TIM-3 expression was not associated with overall survival or T classification, it was associated with resistance to chemotherapy. TIM-3 expression is therefore considered to be a marker for predicting the efficacy of chemotherapy, and TIM-3-associated signals may be a therapeutic target for patients with ATLL.

CXCL10 and CCL2 mRNA expression in monocytes is inversely correlated with the HLA-DR lower fraction of monocytes in patients with renal cell carcinoma.

Circulating cluster of differentiation (CD)14+ human leukocyte antigen (HLA)-DRlow/- monocytes, those with a lower HLA-DR expression or are negative for HLA-DR, are considered to be involved in systemic immunosuppression in patients with several malignant tumors. However, few studies have investigated in detail the gene expression profile of CD14+HLA-DRlow/- monocytes. In the present study, the mRNA expression levels of immune-associated molecules in CD14+ monocytes isolated from healthy donors and patients with renal cell carcinoma (RCC) were analyzed. Consistent with previous studies, the percentage of HLA-DRlow/- cells in CD14+ monocytes was significantly increased in patients with RCC compared with healthy donors. In 3 of the 4 patients who underwent surgical resection of the primary tumor, the percentage of CD14+HLA-DRlow/- cells was significantly decreased following surgery. The mRNA expression levels of cyclooxygenase 2, transforming growth factor ß, interleukin 6R, chemokine (C-C motif) ligand 2 (CCL2), chemokine (C-X-C motif) ligand 10 (CXCL10), oncostatin M, and vascular endothelial growth factor-A in CD14+ monocytes were quantified using reverse transcription-quantitative polymerase chain reaction. The results of the present study revealed that increased expression levels of CCL2 and CXCL10 were inversely correlated with the percentage of CD14+HLA-DRlow/- monocytes. This suggested that monocytes in RCC patients were immunologically suppressed, and that immunosuppression in RCC patients may be due, in part, to the dysfunction of circulating monocytes.

Prognostic Significance of CD169+ Lymph Node Sinus Macrophages in Patients with Malignant Melanoma.

CD169 (sialoadhesin) is a sialic acid receptor that is specifically expressed on macrophages, including lymph node sinus macrophages. Animal studies suggest that CD169(+) macrophages in lymph nodes have properties in preventing cancers. In order to determine the significance of CD169(+) macrophages in patients with malignant melanoma, we evaluated tissue samples from 93 patients to investigate CD169 expression in regional lymph nodes (RLN) and determine the relationship of this expression with overall survival and various clinicopathologic factors. Higher densities of CD169(+) cells were significantly associated with longer overall survival (P = 0.001). A multivariate analysis showed that the density of CD169(+) cells was an independent prognostic factor, with higher densities correlating with higher density of CD8(+) cytotoxic T cells within tumor sites. High CD169 expression in macrophages could be stimulated by IFNα in vitro, and in RLNs, IFNα-producing macrophages and CD303(+) plasmacytoid dendritic cells were identified surrounding CD169(+) macrophages. These data suggest that IFNα-stimulated CD169(+) macrophages in RLNs are closely involved in T-cell-mediated antitumor immunity and may be a useful marker for assessing the clinical prognosis and monitoring antitumor immunity in patients with malignant melanoma.

Sorafenib enhances the antitumor effects of anti-CTLA-4 antibody in a murine cancer model by inhibiting myeloid-derived suppressor cells.

This antitumor effect of sorafenib is considered to be dependent not only on its direct cytotoxicity to cancer cells but also due to the inhibition of myeloid-derived suppressor cells (MDSCs). Recently, a novel antibody against cytotoxic T-lymphocyte antigen 4 (CTLA-4), which activates lymphocytes, is currently in clinical applications. The aim of the present study was to investigate the synergistic antitumor effects of anti-CTLA-4 antibody (Ab) and sorafenib in a murine cancer model. RENCA cells were subcutaneously inoculated into mice, which were randomly divided into 4 treatment groups: sorafenib plus anti-CTLA-4 Ab, sorafenib plus control Ab, vehicle plus anti-CTLA-4 Ab, and vehicle plus control Ab. Single therapy using anti-CTLA-4 Ab suppressed tumor growth, but no difference was noted when compared with the single therapy group using sorafenib. Notably, the greatest decrease in tumor size was noted with sorafenib plus anti-CTLA-4 Ab (combination therapy), and the highest rate of tumor rejection was observed in the combination therapy group. The number of infiltrating CD4- or CD8-positive lymphocytes was strongly increased in the combination therapy group. These in vivo data indicate that sorafenib increased the immunostimulatory effect of anti-CTLA-4 Ab even when sorafenib was used at a low dose. An in vitro study using MDSCs and CD8(+) T cells showed that the inhibitory effect of MDSCs on CD8(+) T cells was significantly abrogated by the combined use of sorafenib and anti-CTLA-4 Ab. Sorafenib suppressed the expression of immunosuppressive factors in MDSCs. These data indicate that combination therapy of sorafenib and anti-CTLA-4 Ab may be effective in advanced kidney cancer patients.