Mechanism for the recruitment of macrophages to cancer site. In vivo concentration gradient of monocyte chemotactic activity

Leukocytes as carriers for targeted cancer drug delivery

INTRODUCTION

Metastasis contributes to over 90% of cancer-related deaths. Numerous nanoparticle platforms have been developed to target and treat cancer, yet efficient delivery of these systems to the appropriate site remains challenging. Leukocytes, which share similarities to tumor cells in terms of their transport and migration through the body, are well suited to serve as carriers of drug delivery systems to target cancer sites.

AREAS COVERED

This review focuses on the use and functionalization of leukocytes for therapeutic targeting of metastatic cancer. Tumor cell and leukocyte extravasation, margination in the bloodstream, and migration into soft tissue are discussed, along with the potential to exploit these functional similarities to effectively deliver drugs. Current nanoparticle-based drug formulations for the treatment of cancer are reviewed, along with methods to functionalize delivery vehicles to leukocytes, either on the surface and/or within the cell. Recent progress in this area, both in vitro and in vivo, is also discussed, with a particular emphasis on targeting cancer cells in the bloodstream as a means to interrupt the metastatic process.

EXPERT OPINION

Leukocytes interact with cancer cells both in the bloodstream and at the site of solid tumors. These interactions can be utilized to effectively deliver drugs to targeted areas, which can reduce both the amount of drug required and various nonspecific cytotoxic effects within the body. If drug delivery vehicle functionalization does not interfere with leukocyte function, this approach may be utilized to neutralize tumor cells in the bloodstream to prevent the formation of new metastases, and also to deliver drugs to metastatic sites within tissues.

Interleukin-17 Produced by Malignant Mesothelioma-Polarized Immune Cells Promotes Tumor Growth and Invasiveness

Malignant mesothelioma (MM) is a highly fatal tumor of inner body membranes, the extensive growth of which is supported by both a weak immunogenicity and the ability to reprogram surrounding immune cells towards tumor-supporting phenotypes. Interleukin-17 (IL-17) is a major inflammatory cytokine which is now accepted as the paradigmatic cytokine of many autoimmune diseases; however, its role in tumor immunology has only been partially unraveled, and no data exist regarding its possible involvement in MM. Thus, in this work we evaluated the ability of MM to induce IL-17 production in immune cells and the effects of IL-17 on MM growth and invasiveness. Our data show for the first time that macrophages and CD4+ T-cells are polarized by MM to produce IL-17, and that this cytokine exerts multiple tumor-supporting effects on both cell growth and invasiveness. These data provide novel evidence of the crosstalk occurring between MM and immune cells and suggest potential targets for the development of new pharmacological approaches for MM treatment.

Potent antitumor effects of combination therapy with IFNs and monocytes in mouse models of established human ovarian and melanoma tumors

Interferon-activated monocytes are known to exert cytocidal activity against tumor cells in vitro. Here, we have examined whether a combination of IFN-α2a and IFN-γ and human monocytes mediate significant antitumor effects against human ovarian and melanoma tumor xenografts in mouse models. OVCAR-3 tumors were treated i.t. with monocytes alone, IFN-α2a and IFN-γ alone or combination of all three on day 0, 15 or 30 post-tumor implantation. Mice receiving combination therapy beginning day 15 showed significantly reduced tumor growth and prolonged survival including complete regression in 40% mice. Tumor volumes measured on day 80 in mice receiving combination therapy (206 mm(3)) were significantly smaller than those of mice receiving the IFNs alone (1,041 mm(3)), monocytes alone (1,111 mm(3)) or untreated controls (1,728 mm(3)). Similarly, combination therapy with monocytes and IFNs of much larger tumor also inhibited OVCAR-3 tumor growth. Immunohistochemistry studies showed a large number of activated macrophages (CD31(+)/CD68(+)) infiltrating into OVCAR-3 tumors and higher densities of IL-12, IP10 and NOS2, markers of M1 (classical) macrophages in tumors treated with combination therapy compared to the controls. Interestingly, IFNs-activated macrophages induced apoptosis of OVCAR-3 tumor cells as monocytes alone or IFNs alone did not mediate significant apoptosis. Similar antitumor activity was observed in the LOX melanoma mouse model, but not as profound as seen with the OVCAR-3 tumors. Administration of either mixture of monocytes and IFN-α2a or monocytes and IFN-γ did not inhibit Lox melanoma growth; however, a significant inhibition was observed when tumors were treated with a mixture of monocytes, IFN-α2a and IFN-γ. These results indicate that monocytes and both IFN-α2a and IFN-γ may be required to mediate profound antitumor effect against human ovarian and melanoma tumors in mouse models.

Near eradication of clinically relevant concentrations of human tumor cells by interferon-activated monocytes in vitro

We have previously reported that low concentrations of interferon (IFN)-activated monocytes exert near-eradicative cytocidal activity against low concentrations of several human tumor cells in vitro. In the present study, we examined 7 human tumor cell lines and 3 diploid lines in the presence or absence of 10 ng/mL IFNα2a and monocytes. The results confirmed strong cytocidal activity against 4 of 7 tumor lines but none against 3 diploid lines. To model larger in vivo tumors, we increased the target cell concentration and determined the concentration of IFNα2a and monocytes, required for cell death. We found that increasing the tumor cell concentration from 10- to 100-fold (10(5) cells/well) required an increase in the concentration of IFNs by over 100-fold and monocytes by 10-fold. High concentrations of monocytes could sometimes kill tumor or diploid cells in the absence of IFN. We may conclude that killing of high concentrations of tumor or diploid cells required high concentrations of monocytes that could sometimes kill in the absence of IFN. Thus, high concentrations of tumor cells required high concentrations of IFN and monocytes to cause near eradication of tumor cells. These findings may have clinical implications.

The ecology of brain tumors: lessons learned from neurofibromatosis-1

Traditionally, cancer studies have primarily focused on mutations that activate growth or survival pathways in susceptible pre-neoplastic/neoplastic cells. However, recent research has revealed a critical role for non-neoplastic cells within the tumor microenvironment in the process of cancer formation and progression. In addition, the existence of regional and developmental variations in susceptible cell types and supportive microenvironments support a model of tumorigenesis in which the dynamic symbiotic relationship between neoplastic and non-neoplastic cell types dictate where and when cancers form and grow. In this review, we highlight advances in neurofibromatosis type 1 (NF1) genetically engineered mouse brain tumor (glioma) modeling to reveal how cellular and molecular heterogeneity in both the pre-neoplastic/neoplastic and non-neoplastic cellular compartments contribute to gliomagenesis and glioma growth.

Primary central nervous system lymphoma secretes monocyte chemoattractant protein 1

The majority of primary central nervous system lymphomas (PCNSL) are diffuse large B-cell lymphomas. Histologically, reactive T lymphocytes and mono-histiocytic cells are found within PCNSL tissue. To clarify the mechanisms of the cellular infiltration, the presence of monocyte chemoattractant protein (MCP-1) was investigated in biopsy samples of 19 cases of PCNSL by means of immunohistochemical staining, double staining with a confocal laser microscope, and Western blot analysis. MCP-1 expression was observed in all PCNSL immunohistochemically. Western blot analysis showed that the concentration of MCP-1 in PCNSL was as high as that in a metastatic brain tumor. In normal brain tissue, MCP-1 was not detected. Confocal laser microscope revealed MCP-1 signals were present in the cells with CD20, a B-cell marker. We concluded that lymphoma cells produced MCP-1, which is an additional cytokine involved in the pathogenesis of PCNSL.

Head and neck squamous cell carcinoma spheroid- and monocyte spheroid-stimulated IL-6 and monocyte chemotactic protein-1 secretion are related to TNM stage, inflammatory state and tumor macrophage density

Monocyte fragment (F)-spheroid-stimulated and F-spheroid IL-6 and monocyte chemotactic protein (MCP)-1 secretion are related to inflammatory state, macrophage density and the TNM stage of patients with head and neck squamous cell carcinoma (HNSCC). Fragment (F)-spheroids from HNSCC patients in vitro secrete and stimulate autologous monocytes to secrete IL-6 and MCP-1. The aim of this investigation was to study this cytokine secretion in relation to other cytokines, spheroid composition and host factors.In series I (n=14) the densities of epithelial cells, fibroblasts and macrophages were determined in sections from F-spheroids and donor tissue. In series II (n=17) the TNM stage, donor inflammatory state, macrophage density and the secretion of F-spheroid- and monocyte F-spheroid-stimulated IL-6, MCP-1 and tumor necrosis factor (TNF)-alpha were determined. Epithelial cells were partly replaced by interstitial tissue during spheroid formation. Malignant (M) F-spheroids secreted more MCP-1 than benign (B) F-spheroids. No F-spheroid secreted measurable amounts of TNF-alpha. Monocytes secreted more IL-6 when co-cultured with MF- compared to BF-spheroids. Monocyte IL-6 MF- and MCP-1 MB-spheroid-stimulated secretion correlated with macrophage density. In addition, there was an association between MF- and BF-spheroid-stimulated monocyte cytokine secretion, as well as between BF- and MF-spheroid-stimulated MCP-1 secretion. An inverse relation was also noted between the erythrocyte sedimentation rate at monocyte harvest and the monocyte MCP-1 F-spheroid responses.

Profiling of differentially expressed chemotactic-related genes in MCP-1 treated macrophage cell line using human cDNA arrays

AIM: To study the global gene expression of chemotactic genes in macrophage line U937 treated with human monocyte chemoattractant protein-1 (MCP-1) through the use of ExpreeChip^TMHO₂ cDNA array.

METHODS: Total RNA was extracted from MCP-1 treated macrophage line U937 and normal U937 cells, reversely transcribed to cDNA, and then screened in parallel with HO₂ human cDNA array chip. The scanned result was additionally validated using RT-PCR.

RESULTS: The result of cDNA array showed that one chemotactic-related gene was up-regulated more than two-fold (RANTES) and seven chemotactic-related genes were down-regulated more than two-fold (CCR1, CCR5, ccl16, GROβ, GROγ, IL-8 and granulocyte chemotactic protein 2) in MCP-1 treated U937 cells at mRNA level. RT-PCR analysis of four of these differentially expressed genes gave results consistent with cDNA array findings.

CONCLUSION: MCP-1 could influence some chemokine and receptor expressions in macrophages in vitro. MCP-1 mainly down-regulates the expression of chemotactic genes influencing neutrophilic granulocyte expression (GROβ, GROγ, IL-8 and granulocyte chemotactic protein 2), and the mRNA level of CCR5, which plays a critical role in many disorders and illnesses.

A potential role of macrophage activation in the treatment of cancer

One of the functions of macrophages is to provide a defense mechanism against tumor cells. In the last decades the mechanism of tumor cell killing by macrophages have been studied extensively. The tumor cytotoxic function of macrophages requires stimulation either with bacterial cell wall products such as lipopolysaccharide (LPS) or muramyldipeptide (MDP) or with cytokines such as interferon-gamma (IFN-gamma) and granulocyte-macrophage colony-stimulating factor (GM-CSF). Activated macrophages secrete several substances that are directly involved in tumor cell killing i.e. tumor necrosis factor (TNF) and nitric oxide (NO). On the other hand, substances are secreted that are able to stimulate tumor cell growth, depending on the stage and the nature of the tumor. Several clinical trials have been performed aiming at the activation of macrophages or dendritic cells, a subpopulation of the macrophages. In this review we will summarize and discuss experimental studies and clinical trials based on the activation of macrophages.

Use of insulin to improve [18 F]fluorodeoxyglucose labelling and retention for in vivo positron emission tomography imaging of monocyte trafficking

While 18F-FDG labelling of monocytes would allow in vivo trafficking with positron emission tomography (PET), present methods suffer from poor retention of radioactivity. We investigated the feasibility of utilizing insulin for improved [18F]fluorodeoxyglucose (18F-FDG) labelling. Separated human monocytes and lymphocytes were labelled with 18F-FDG with or without 3 h insulin pre-incubation. Insulin had no effect on lymphocyte labelling (21.4+/-0.8% vs 20.8+/-1.1% efficiency, P=NS). However, for monocytes, insulin pre-incubation led to a 169+/-9% increase in labelling efficiency (19.3+/-4.1 vs 32.5+/-1.8, P<0.05), without significant effects on cell activation or viability. Moreover, while only 57.7+/-4.8% and 40.4+/-5.6% of the 18F-FDG was retained at 1 and 3 h for controls, the retention rate increased to 91.6+/-2.1% (P=0.01) and 86.5+/-1.9% (P<0.01) after insulin pre-incubation. Improved 18F-FDG retention was accompanied by a 70.3+/-7.4% decrease in glucose-6-phosphatase activity (P=0.02). PET imaging of rats showing hepatic ischaemia-reperfusion injury demonstrated higher liver uptake for monocytes labelled after insulin treatment. Thus, insulin improves monocytic 18F-FDG uptake and retention, and may provide a feasible labelling method for PET imaging.

Monocyte chemoattractant protein-1-induced activation of p42/44 MAPK and c-Jun in murine peritoneal macrophages: a potential pathway for macrophage activation

The role of monocyte chemoattractant protein-1 (MCP-1) in mediating the infiltration and activation of monocytes/macrophages into the sites of inflammation or tumor growth is well documented, but the molecular mechanism(s) involved in the process is poorly understood. In the current investigation, we demonstrate activation of the p42/44 MAPK-mediated signal transduction in murine peritoneal macrophages on stimulation with MCP-1 (10-100 ng/ml) in vitro. The p42/44 MAPK activation was determined by studying the expression of the phosphorylated p42/44 MAPK (Thr202/Tyr204) in the MCP-1-treated macrophages. This response was found to be rapid and time dependent, detectable within 5 min of MCP-1 stimulation. PD98058 (5-50 microM), a specific inhibitor of MAPK kinase (MEK) inhibited the p42/44 MAPK phosphorylation, indicating the specificity of the response. Furthermore, the MCP-1-induced phosphorylation of p42/44 MAPK was found to be blocked by pertussis toxin (100 ng/ml), tyrosine kinase inhibitor-genestein (10 ng/ml), PI3K inhibitor-wortmannin (20-200 microM), and anti-CCR2 antibody (2.5 microg/ml). Additionally, phosphorylation of JNK and activation of the transcription factor, c-Jun, were also noted in response to MCP-1 treatment. Lastly, the MCP1-induced p42/44 MAPK activity was correlated with the functional activation of macrophages by demonstrating the dose-specific inhibition of actin polymerization, macrophage-mediated tumor cell cytotoxicity, and tumor necrosis factor-alpha (TNF-alpha) transcription/production afforded by PD98059 in the MCP-1-treated macrophages. Taken together, these data suggest the involvement of the p42/44 MAPK/c-Jun pathway in the signal transduction process, leading to activation of murine peritoneal macrophages.

MHC class I-related neonatal Fc receptor for IgG is functionally expressed in monocytes, intestinal macrophages, and dendritic cells

The neonatal Fc receptor (FcRn) for IgG, an MHC class I-related molecule, functions to transport IgG across polarized epithelial cells and protect IgG from degradation. However, little is known about whether FcRn is functionally expressed in immune cells. We show here that FcRn mRNA was identifiable in human monocytes, macrophages, and dendritic cells. FcRn heavy chain was detectable as a 45-kDa protein in monocytic U937 and THP-1 cells and in purified human intestinal macrophages, peripheral blood monocytes, and dendritic cells by Western blot analysis. FcRn colocalized in vivo with macrosialin (CD68) and Ncl-Macro, two macrophage markers, in the lamina propria of human small intestine. The heavy chain of FcRn was associated with the beta(2)-microglobulin (beta(2)m) light chain in U937 and THP-1 cells. FcRn bound human IgG at pH 6.0, but not at pH 7.5. This binding could be inhibited by human IgG Fc, but not Fab. FcRn could be detected on the cell surface of activated, but not resting, THP-1 cells. Furthermore, FcRn was uniformly present intracellularly in all blood monocytes and intestinal macrophages. FcRn was detectable on the cell surface of a significant fraction of monocytes at lower levels and on a small subset of tissue macrophages that expressed high levels of FcRn on the cell surface. These data show that FcRn is functionally expressed and its cellular distribution is regulated in monocytes, macrophages, and dendritic cells, suggesting that it may confer novel IgG binding functions upon these cell types relative to typical Fc gamma Rs: Fc gamma RI, Fc gamma RII, and Fc gamma RIII.

Macrophages and microvessel density in tumors of the ovary

Macrophages are members of the mononuclear phagocyte system and synthesize and release many angiogenesis stimulators and inhibitors. Previous studies have demonstrated heterogeneous macrophage populations in ovarian tumors. The aim of this study was to compare macrophage number between different types of ovarian tumors and between regions of high (HVD) and average (AVD) microvessel density (MVD). Macrophages were visualized using CD68 antibody. Previously determined regions of HVD and AVD were located on CD68 immunostained sections and image analysis software was used to count the number of positively stained cells per square millimeter. CD68-positive macrophage number did not differ between benign, mucinous, and serous ovarian tumors or between regions of HVD and AVD (ANOVA; P > 0.05). In both HVD and AVD regions of benign tumors, macrophage number positively correlated with MVD (Spearman rank correlation coefficient; P < 0.03). In contrast, a small but significant negative correlation between macrophage number and MVD was observed in HVD regions of serous tumors (Spearman rank correlation coefficient; P > 0.05). Macrophage infiltration does not appear to differ between ovarian tumor types; however, macrophages may have a positive influence on the vascularization of benign ovarian tumors.

Cathepsin D in host stromal cells is associated with more highly vascular and aggressive invasive breast carcinoma

AIMS

To determinate the relationship between tumoral angiogenesis and cathepsin D (CD) expression in tumour and host stromal cells of invasive breast carcinoma, and to examine its association with classical prognostic factors such as lymph node status, histological grade, tumour size, mitotic rate, peritumoral lymphovascular invasion and oestrogen receptor (ER) status.

METHODS AND RESULTS

Sections from 102 invasive breast carcinoma were cut from the archival formalin-fixed, paraffin-embedded tissue blocks and stained using immunohistochemistry for the endothelial cell adhesion molecule (CD31) and CD. Microvessel density was assessed by counting vessels in the three most vascular areas at x400 field. The counts were expressed as the highest counts within any x400 field. The evaluation of immunostaining for CD was performed separately in both the parenchymal and stromal cells. Microvessel density was correlated positively with histological grade and peritumoral lymphovascular invasion, and correlated inversely with ER status. Positive CD staining of tumour cells was more frequent in positive ER tumours and was not significantly associated with the other classical prognostic factors. However, moderate to strong staining of host cells was correlated with higher histological grade, higher mitotic index and lack of ER protein. There was a statistically significant association between CD expression of host stromal cells and higher vessel count.

CONCLUSIONS

CD in host stromal cells is associated with more aggressive tumours and with a higher intratumoral microvessel density. Evaluation of CD in combination with angiogenic activity may be of some help in more accurately predicting the biological behaviour of breast carcinoma.

The monocyte chemotactic protein a (MCP-1) and interleukin 8 (IL-8) in Hodgkin's disease and in solid tumours

AIMS

Monocyte chemotactic protein 1 (MCP-1) and interleukin 8 (IL-8) are small, inducible proteins with chemotactic activity for specific subsets of leucocytes. The possibility that MCP-1 and IL-8 are produced in tissues involved by Hodgkin's disease, thus contributing to the inflammatory-type background of the lesion, was investigated.

METHODS

The presence of RNA transcripts for MCP-1 and IL-8 was investigated in biopsy samples of 24 cases of Hodgkin's disease, 17 non-Hodgkin's malignant lymphomas, 30 solid tumours, and 30 histologically normal tissues by means of reverse transcription-polymerase chain reaction (RT-PCR)/Southern blot analysis.

RESULTS

MCP-1 expression was detected in 23 of 24 cases of Hodgkin's disease, in seven of 17 cases of B cell non-Hodgkin's lymphoma, and in seven of 14 cases of reactive lymphoid hyperplasia. IL-8 was present in six of 14 cases of Hodgkin's disease, and was seen only rarely in B cell non-Hodgkin's lymphoma and in reactive lymphoid tissues. MCP-1 and IL-8 RNA transcripts were detected in 13 of 25 carcinomas originating from the lung, breast, thyroid, and ovary.

CONCLUSIONS

These findings are consistent with the possibility that MCP-1 and IL-8 are two additional cytokines involved in the pathogenesis of Hodgkin's disease.

Urinary levels of monocyte chemo-attractant protein-1 correlate with tumour stage and grade in patients with bladder cancer

OBJECTIVE

To determine if the chemokine monocyte chemo-attractant protein-1 (MCP-1) is produced locally in patients with bladder cancer and to analyse a possible correlation between tumour stage, grade and metastatic spread, and the urinary and systemic levels of MCP-1. PATIENTS SUBJECTS AND METHODS: Urine and serum samples were obtained from 60 patients with bladder cancer and 20 control subjects. Tumour stage, grade, metastasis and nodal status were assessed. MCP-1 levels in serum and urine were determined using a sandwich enzyme-linked immunosorbent assay. Two transitional cell cancer cell lines (grade I and grade III) were analysed for MCP-1 production under normal and nutritive-stress cell culture.

RESULTS

The correlation of urinary MCP-1 levels with tumour stage, grade and distant metastasis was highly significant. Patients with stage T2-T4 bladder cancer had three to fourfold higher mean MCP-1 concentrations (pg/mL) in their urine than those with T1 stage tumours or than the controls (controls 260; T1 359; T2 967; T3 917; T4 1829; P < 0.005). A tumour grade of > GI and the existence of distant metastasis (M1) also correlated significantly with higher urinary MCP-1 levels (GI 373; GII 661; GIII 1111; M0 644; M1 1379; P < 0.05). No differences in circulating serum MCP-1 level were detected between controls and patients. The low-grade (GI) RT4 bladder cancer cell line produced only traces of MCP-1, which did not change under nutritional stress; in contrast, the highly malignant T24 bladder cancer cell line (GIII) spontaneously secreted large amounts of MCP-1 (approximately 7000 pg/mL) which increased under nutritive stress to 13,000 pg/mL.

CONCLUSION

MCP-1, as a potent monocyte chemo-attractant to tumour sites, is probably produced by bladder cancer cells; MCP-1 levels in the vicinity of the tumour (i.e. urine) correlate significantly with TNM stage and grade. As has already been shown in other neoplasms, the resulting monocyte/macrophage infiltrate possibly facilitates tumour neovascularization and tissue invasion. Therefore, MCP-1 levels in the urine of patients with bladder cancer may be a prognostic marker for the natural course of the disease, and modulation of this chemokine might be a future therapeutic approach for adjuvant treatment of bladder cancer.

Human tumour-associated macrophages differentiate into osteoclastic bone-resorbing cells

Macrophages are commonly found within osteolytic secondary carcinomas in bone, but the manner in which these cells contribute to malignant bone resorption is uncertain. Macrophages isolated from primary breast carcinomas were co-cultured for up to 21 days with UMR 106 rat osteoblast-like cells on bone slices and glass coverslips in the presence and absence of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] and human macrophage colony stimulating factor (M-CSF). Cell cultures were then assessed for the presence of phenotypic markers of macrophage and osteoclast differentiation. Isolated cells were negative for osteoclast markers including tartrate-resistant acid phosphatase (TRAP), vitronectin receptor (VNR), and the ability to carry our lacunar bone resorption, but were positive for CD11b and CD14, macrophage markers which are not present on osteoclasts. In 21-day co-cultures of breast carcinoma tumour-associated macrophages (TAMs) and UMR 106 cells, incubated in the presence of 1,25(OH)2D3 and M-CSF, numerous TRAP- and VNR-positive multinucleated cells capable of extensive lacunar resorption were formed. Contact with UMR 106 cells and the presence of 1,25(OH)2D3 and M-CSF were absolute requirements for differentiation of human breast carcinoma TAMs into mature functional osteoclasts. TAM-osteoclast differentiation may represent an important cellular mechanism of osteolysis in metastatic skeletal carcinomas.

Identification of human complement factor H as a chemotactic protein for monocytes

We used chromatographic separation to purify to homogeneity a monomeric monocyte chemotactic protein of 150 kDa contained in mesothelioma pleural effusions. It was identified by N-terminal amino acid sequencing and immunoblotting as complement factor H, an inhibitor of the alternative complement pathway. Specific antibodies against factor H inhibited the monocyte chemotactic activity of the purified protein, which was most active at 10 nM. Factor H is a restrictive factor of alternative complement pathway activation. The new chemotactic function assigned to factor H in recruiting monocytes to the mesothelioma site might contribute to malignant cell phagocytosis via the iC3b/complement receptor type 3 pathway. These functions link the humoral and cellular immune systems.

Correlation of two methods for determination of cathepsin D in breast carcinoma (immunohistochemistry and ELISA in cytosol)

We have studied the correlation of two methods (immunohistology and ELISA in cytosol) of cathepsin D (CD) determination in breast carcinoma patients. Fifty six specimens of tumor tissue were collected consecutively, and CD expression in tumor tissue and tissue macrophages was determined by standard immunohistochemistry using the aNCL-CDm anti-cathepsin D mouse monoclonal antibody (Novocastra Laboratories Ltd., Newcastle, UK). Additionally, CD concentration was determined by ELISA in cytosol of the same breast carcinoma specimens. CD positivity was correlated with tumor size, histological grade of tumor, and the cytosol progesterone adn estrogen receptor concentrations. There was no statistically significant correlation between examined parameters and either CD positivity by immunohistochemistry or cytosol CD concentration. The correlation between CD expression in tumor cells of breast carcinoma by immunohistochemistry and cytosol CD positivity was not found either. However, there was a significant association between abundance of CD positive stromal macrophages and cytosol CD concentration in all histological tumor types (p < 0.05). CD positive macrophages were abundant in most of cytosol CD positive specimens. These results suggest that breast cancer cytosol CD concentration is the cumulative result of CD content in both carcinoma cells and stromal macrophages.

The detection and localization of monocyte chemoattractant protein-1 (MCP-1) in human ovarian cancer

Chemokines may control the macrophage infiltrate found in many solid tumors. In human ovarian cancer, in situ hybridization detected mRNA for the macrophage chemokine monocyte chemoattractant protein-1 (MCP-1) in 16/17 serous carcinomas, 4/4 mucinous carcinomas, 2/2 endometrioid carcinomas, and 1/3 borderline tumors. In serous tumors, mRNA expression mainly localized to the epithelial areas, as did immunoreactive MCP-1 protein. In the other tumors, both stromal and epithelial expression were seen. All tumors contained variable numbers of cells positive for the macrophage marker CD68. MCP-1 mRNA was also detected in the stroma of 5/5 normal ovaries. RT-PCR demonstrated mRNA for MCP-1 in 7/7 serous carcinomas and 6/6 ovarian cancer cell lines. MCP-1 protein was detected by ELISA in ascites from patients with ovarian cancer (mean 4.28 ng/ml) and was produced primarily by the cancer cells. Human MCP-1 protein was also detected in culture supernatants from cell lines and in ascites from human ovarian tumor xenografts which induce a peritoneal monocytosis in nude mice. We conclude that the macrophage chemoattractant MCP-1 is produced by epithelial ovarian cancer and that the tumor cells themselves are probably a major source. MCP-1 may contribute to the accumulation of tumor-associated macrophages, which may subsequently influence tumor behavior.

Functional role of the cis-acting elements in human monocyte chemotactic protein-1 gene in the regulation of its expression by phorbol ester in human glioblastoma cells

The monocyte chemotactic protein-1 (MCP-1) is a 76 amino acid protein that specifically attracts monocytes. The expression of MCP-1 gene can be induced by lipopolysaccharides (LPS), phorbol esters (TPA) and several cytokines. However, how they regulate MCP-1 gene expression is not known. We tested whether the two putative TPA-responsive elements (TREs) and one kappa B enhancer-like region found in the MCP-1 promoter region, are involved in this regulation of MCP-1 gene expression. The 5' untranslated region of MCP-1 gene was linked to chloramphenicol acetyl transferase (CAT) reporter gene and transfected into human glioblastoma cells in which endogenous MCP gene expression was found to be stimulated by TPA and tumor necrosis factor-alpha (TNF-alpha). The 128 bp 5'-flanking region containing one TRE was adequate for basal promoter activity but the presence of both TREs in the MCP-1 promoter region were needed to give TPA responsive enhancement (2.5 fold) of expression of the marker gene. Mutations in either of the TRE's could abolish the TPA induction of CAT expression. Replacement of the kappa B enhancer-like element with a TRE-like sequence caused a 10-fold enhancement of CAT expression by TPA treatment. Random mutation of kappa B enhancer-like element did not affect CAT expression or its TPA induction. None of the MCP promoter constructs showed significant increase in CAT expression by treatment with tumor necrosis factor-alpha (TNF-alpha). This result suggested that the TNF regulation of MCP-1 gene involves other parts of the gene besides the proximal 5' flanking region.

Association of different macrophage phenotypes with infiltrating and non-infiltrating areas of tumor-host interface in colorectal carcinoma

At the tumor-host interface (interface) of well differentiated tubulary or tubulopapillary colorectal carcinomas infiltrative, poorly demarcated and non-infiltrative, well bordered areas alternate. The composition of the inflammatory infiltrate within the desmoplastic stroma of the central tumor part and the interface was analyzed, particularly emphasizing differences between infiltrative and non-infiltrative areas of the interface. Of particular interest was the distribution of the following recently identified, functionally different human macrophage phenotypes: the 27E10-positive phenotype, an inflammatory macrophage, the 25F9-positive phenotype, a mature, resident macrophage and the RM3/1-positive phenotype, associated with anti-inflammatory function. It was found that macrophages were the dominating cells in the inflammatory infiltrate of both central tumor part and interface and that the number of B-cells and NK-cells were negligible. The 27E10-positive phenotype revealed a strong association with infiltrative areas at the interface, whereas the resident macrophage together with the RM3/1 was associated with sharply bordered tumor areas dominating within the tumor stroma, particularly in carcinomas with marked desmoplastic stroma response. These findings suggest that different macrophage phenotypes, localized in different regions of the carcinoma, have different effects on tumor cells.

Synergic in vitro effects of interleukin-2 and tau-interferon on the migration of blood monocytes from control subjects and patients with lung cancer

BACKGROUND

Macrophages can play a major role against cancer by exerting their cytotoxic activity against tumor cells. The presence of macrophages in tumor stroma is related to the recruitment of circulating blood monocytes through the release of chemotactic factors by cancer cells. However, fewer blood monocytes from patients with cancer, such as lung cancer, migrate from in vivo and in vitro, compared with blood monocytes control subjects.

METHODS

Two cytokines, interleukin-2 (IL-2) and tau-interferon (tau-INF), proposed in the treatment of cancer, were tested for their ability to modulate the migratory response in modified Boyden chemotactic chambers of blood monocytes obtained from control subjects and patients with lung cancer in the presence of two chemotactic factors: N-formylmethionyl-leucyl-phenylalanine and complement fraction C5a (C5a).

RESULTS

Incubation with IL-2 and tau-INF resulted in a dose-dependent depression of the migration of blood monocytes from control subjects and patients with lung cancer. IL-2 depression was induced by IL-2 concentrations of 10(5) units/ml, and tau-IFN effects were measured for concentrations of 100 mu/ml. Furthermore, when low concentrations of IL-2 were tested in combination with low concentrations of tau-IFN, dose-dependent depression of blood monocyte migration occurred.

CONCLUSIONS

Dose-dependent depression of blood monocyte migration may modulate the inflammatory component of tumor stroma in patients with lung cancer treated with these cytokines. It may also explain, in part, the high incidence of infections in patients treated with IL-2.