Monocyte chemotactic proteins from human tumor cells

Thymidine phosphorylase and angiogenesis in early stage esophageal squamous cell carcinoma

BACKGROUND

The relationship between thymidine phosphorylase (TP) and angiogenesis at the early stage of esophageal squamous cell carcinoma has been unclear.

METHODS

Using 14 samples of normal squamous epithelium, 11 samples of low-grade intraepithelial neoplasia, and 64 samples of superficial esophageal cancer, microvessel density (MVD) was estimated using immunostaining for CD34 and CD105. TP expression was also evaluated in both cancer cells and stromal monocytic cells (SMCs). We then investigated the correlation between MVD and TP expression in both cancer cells and SMCs.

RESULTS

On the basis of the above parameters, MVD was significantly higher in cancerous lesions than in normal squamous epithelium. In terms of CD34 and CD105 expression, MVD showed a gradual increase from normal squamous epithelium, to low-grade intraepithelial neoplasia, and then to M1 and M2 cancer, and M3 or deeper cancer. M1 and M2 cancer showed overexpression of TP in both cancer cells and SMCs. There was no significant correlation between TP expression in cancer cells and MVD estimated from CD34 (rS = 0.16, P = 0.21) or CD105 (rS = 0.05, P = 0.68) expression. Significant correlations were found between TP expression in SMCs and CD34-related (rS = 0.46, P < 0.001) and CD105-related (rS = 0.34, P < 0.01) MVD. In M3 or deeper cancers, there were no significant correlations between TP expression in cancer cells or SMCs and venous invasion, lymphatic invasion, and lymph node metastasis.

CONCLUSION

TP expression is activated in both cancer cells and stromal monocytic cells at the very early stage of ESCC progression. TP expression in SMCs, rather than in cancer cells, is significantly correlated with angiogenesis.

Chemotherapy of colorectal liver metastases induces a rapid rise in intermediate blood monocytes which predicts treatment response

We have previously reported that intermediate monocytes (CD14(++)/CD16(+)) were increased in colorectal cancer (CRC) patients, while the subset of pro-angiogenic TIE2-expressing monocytes (TEMs) was not significantly elevated. This study was designed to evaluate changes in frequency and function of intermediate monocytes and TEMs during chemotherapy and anti-angiogenic cancer treatment and their relation to treatment response. Monocyte populations were determined by flow cytometry in 60 metastasized CRC (mCRC) patients who received neoadjuvant chemotherapy with or without bevacizumab. Blood samples were taken before treatment, after two therapy cycles, at the end of neoadjuvant therapy and immediately before surgical resection of liver metastases. Neoadjuvant treatment resulted in a significant increase in circulating intermediate monocytes which was most pronounced after two cycles and positively predicted tumor response (AUC = 0.875, p = 0.005). With a cut-off value set to 1% intermediate monocytes of leukocytes, this parameter showed a predictive sensitivity and specificity of 75% and 88%. Anti-angiogenic therapy with bevacizumab had no impact on monocyte populations including TEMs. In 15 patients and six healthy controls, the gene expression profile and the migratory behavior of monocyte subsets was evaluated. The profile of intermediate monocytes suggested functions in antigen presentation, inflammatory cytokine production, chemotaxis and was remarkably stable during chemotherapy. Intermediate monocytes showed a preferential migratory response to tumor-derived signals in vitro and correlated with the level of CD14(+)/CD16(+) monocytic infiltrates in the resected tumor tissue. In conclusion, the rapid rise of intermediate monocytes during chemotherapy may offer a simple marker for response prediction and a timely change in regimen.

Exosomes released by chronic lymphocytic leukemia cells induce the transition of stromal cells into cancer-associated fibroblasts

Exosomes derived from solid tumor cells are involved in immune suppression, angiogenesis, and metastasis, but the role of leukemia-derived exosomes has been less investigated. The pathogenesis of chronic lymphocytic leukemia (CLL) is stringently associated with a tumor-supportive microenvironment and a dysfunctional immune system. Here, we explore the role of CLL-derived exosomes in the cellular and molecular mechanisms by which malignant cells create this favorable surrounding. We show that CLL-derived exosomes are actively incorporated by endothelial and mesenchymal stem cells ex vivo and in vivo and that the transfer of exosomal protein and microRNA induces an inflammatory phenotype in the target cells, which resembles the phenotype of cancer-associated fibroblasts (CAFs). As a result, stromal cells show enhanced proliferation, migration, and secretion of inflammatory cytokines, contributing to a tumor-supportive microenvironment. Exosome uptake by endothelial cells increased angiogenesis ex vivo and in vivo, and coinjection of CLL-derived exosomes and CLL cells promoted tumor growth in immunodeficient mice. Finally, we detected α-smooth actin-positive stromal cells in lymph nodes of CLL patients. These findings demonstrate that CLL-derived exosomes actively promote disease progression by modulating several functions of surrounding stromal cells that acquire features of cancer-associated fibroblasts.

Modeling human carcinomas: physiologically relevant 3D models to improve anti-cancer drug development

Anti-cancer drug development is inefficient, mostly due to lack of efficacy in human patients. The high fail rate is partly due to the lack of predictive models or the inadequate use of existing preclinical test systems. However, progress has been made and preclinical models were improved or newly developed, which all account for basic features of solid cancers, three-dimensionality and heterotypic cell interaction. Here we give an overview of available in vivo and in vitro models of cancer, which meet the criteria of being 3D and mirroring human tumor-stroma interactions. We only focus on drug response models without touching models for pharmacokinetic and dynamic, toxicity or delivery aspects.

Cancer seeding contributes to intestinal anastomotic dehiscence

BACKGROUND

Surgical wounds in cancer patients have a relatively high dehiscence rate. Although colon cancer resections are performed so as to include macroscopically non-involved tissues, some cancer cells can be present in the line of transection. The local healing process may facilitate proliferation of these localized cancer cells and the high cytokine concentration within the healing wound may also attract cancer cells from distant sites to migrate into the wound area. The growing tumor cells may then stretch the wound, hampering its contraction process.

METHODS

The aim of the study was to monitor and compare, using immunohistochemical methods, the healing process of intestinal anastomosis in both normal rats and in rats with disseminated cancer (the CC531 colon cancer model).

RESULTS

There was a significantly higher rate of anastomotic dehiscence in the group of rats with disseminated cancer, than in the group of normal rats. There were no significant differences between the two groups in the levels of mononuclear wound infiltration or of formation of connective tissue or new vessels. All anastomotic wounds in animals with disseminated cancer had abundant infiltrates of both migrating and proliferating cancer cells.

CONCLUSIONS

We confirmed that the environment of a healing wound attracts cancer cells. Migration of cancer cells to the wound and centrifugal cancer proliferation may adversely affect the healing process and cause wound disruption.

Myeloid cell receptor LRP1/CD91 regulates monocyte recruitment and angiogenesis in tumors

Recruitment of monocytes into sites of inflammation is essential in the immune response. In cancer, recruited monocytes promote invasion, metastasis, and possibly angiogenesis. LDL receptor-related protein (LRP1) is an endocytic and cell-signaling receptor that regulates cell migration. In this study, we isografted PanO2 pancreatic carcinoma cells into mice in which LRP1 was deleted in myeloid lineage cells. Recruitment of monocytes into orthotopic and subcutaneous tumors was significantly increased in these mice, compared with control mice. LRP1-deficient bone marrow-derived macrophages (BMDM) expressed higher levels of multiple chemokines, including, most prominently, macrophage inflammatory protein-1α/CCL3, which is known to amplify inflammation. Increased levels of CCL3 were detected in LRP1-deficient tumor-associated macrophages (TAM), isolated from PanO2 tumors, and in RAW 264.7 macrophage-like cells in which LRP1 was silenced. LRP1-deficient BMDMs migrated more rapidly than LRP1-expressing cells in vitro. The difference in migration was reversed by CCL3-neutralizing antibody, by CCR5-neutralizing antibody, and by inhibiting NF-κB with JSH-23. Inhibiting NF-κB reversed the increase in CCL3 expression associated with LRP1 gene silencing in RAW 264.7 cells. Tumors formed in mice with LRP1-deficient myeloid cells showed increased angiogenesis. Although VEGF mRNA expression was not increased in LRP1-deficient TAMs, at the single-cell level, the increase in TAM density in tumors with LRP1-deficient myeloid cells may have allowed these TAMs to contribute an increased amount of VEGF to the tumor microenvironment. Our results show that macrophage density in tumors is correlated with cancer angiogenesis in a novel model system. Myeloid cell LRP1 may be an important regulator of cancer progression.

A novel mechanism for anti-EGFR antibody action involves chemokine-mediated leukocyte infiltration

Overexpression of the epidermal growth factor receptor (EGFR) is a hallmark of squamous cell carcinoma of the head and neck (SCCHN). Monoclonal antibodies (mAbs) against EGFR are currently used for therapy of recurrent or metastatic disease; however, their mode of action is not completely understood. To investigate the immunological effects of anti-EGFR mAb, we generated a three-dimensional spheroid model of EGFR-expressing SCCHN and used this model to study the effect of anti-EGFR mAb on leukocyte migration toward tumors. Pretreatment with the blocking anti-EGFR mAb EMD 72000, its F(ab')2 fragments or an EGFR tyrosine kinase inhibitor led to substantially increased leukocyte infiltration into EGFR overexpressing tumor spheroids, but not into those with low EGFR expression. Nonblocking anti-EGFR mAb or fibroblast-specific mAb did not affect leukocyte infiltration, suggesting that the observed increase in leukocyte infiltration depends on interference with EGFR activation. Using a human cytokine macroarray, we demonstrated that the blockade of EGFR by anti-EGFR mAb in EGFR-overexpressing SCCHN cells leads to differential expression of several cytokines and chemokines, including the chemokine MCP-1/CCL-2. The significant upregulation of MCP-1/CCL2 on exposure to anti-EGFR mAb was confirmed by quantitative PCR and enzyme-linked immunospot analyses. Moreover, blocking anti-MCP-1 antibody inhibited leukocyte migration toward tumor cells induced by anti-EGFR mAb, pointing to an important role of MCP-1/CCL2 in anti-EGFR mAb-induced leukocyte migration. Our findings demonstrate that anti-EGFR mAb induces leukocyte infiltration to tumor spheroids by upregulating chemokine expression. This novel mechanism for anti-EGFR mAb action may contribute to the antitumor effects of anti-EGFR mAb in vivo.

Macrophage-targeted photosensitizer conjugate delivered by intratumoral injection

A conjugate between maleylated albumin and a photosensitizer (PS) shows cell type specific targeting to macrophages via the scavenger receptor. Administration of this conjugate to a tumor-bearing mouse followed by illumination may allow selective destruction of macrophages within tumors. There is accumulating evidence that tumor-associated macrophages contribute to tumor growth, invasiveness, metastasis, and immune suppression. We tested the intravenous (IV) injection of a conjugate between maleylated albumin and chlorin(e6) to BALB/c mice bearing three tumor types with differing proportions of tumor-associated macrophages. The accumulation of PS within the tumors after IV injection and 24 h incubation time was disappointing, and we therefore investigated intratumoral (IT) injection. This gave 20-50 times greater concentrations of PS within the tumor compared to IV injection as determined by tissue extraction. Furthermore the amounts of PS in each tumor type correlated well with the numbers of macrophages both as determined by extraction from bulk tumor and fluorescence quantification and as determined by tissue dissociation to a single cell suspension and two-color flow cytometry with macrophage-specific antibodies. IT injection of nonconjugated PS gave lower tumor accumulation that did not correlate with macrophage content. IT injection of targeted macromolecular delivery systems is an underexplored area and worthy of further study.

Monocyte chemoattractant protein-1 transfection induces angiogenesis and tumorigenesis of gastric carcinoma in nude mice via macrophage recruitment

PURPOSE

Monocyte chemoattractant protein-1 (MCP-1) is a chemokine that has various roles in tumor development and progression. We previously reported that expression of MCP-1 is associated with macrophage infiltration and tumor vessel density in human gastric carcinomas. The present study was undertaken to obtain direct evidence that MCP-1 participates in recruitment of macrophages and induction of angiogenesis.

EXPERIMENTAL DESIGN

We did transfection experiments to analyze the role of MCP-1 in tumorigenicity and angiogenesis in gastric carcinoma in nude mice. The human MCP-1 gene cloned into the BCMGS-Neo expression vector was transfected into the human gastric carcinoma TMK-1 cell line. We examined tumor volumes with the ectopic s.c. xenograft model and tumorigenicity with the orthotopic gastric xenograft model. We determined intratumor microvessel counts and tumor-infiltrating macrophage counts by immunohistochemical staining.

RESULTS

There was no difference in in vitro proliferation between MCP-1-transfected TMK-1 cells and mock-transfected (control) cells; however, MCP-1 transfectants induced tumor growth in ectopic xenografts and increased tumorigenicity and induced lymph node metastases and ascites in orthotopic xenografts. In both ectopic and orthotopic xenograft models, strong infiltration of macrophages was observed within and around the tumors after implantation of MCP-1 transfectants whereas fewer macrophages were seen after inoculation of control cells. The microvessel density was significantly higher in tumors produced by MCP-1 transfectants than in control tumors.

CONCLUSIONS

MCP-1 produced by gastric carcinoma cells may regulate angiogenesis via macrophage recruitment. MCP-1 may be a potential target for antiangiogenic therapy for gastric carcinoma.

Viable head and neck tumor spheroids stimulate in vitro autologous monocyte MCP-1 secretion through soluble substances and CD14/lectin-like receptors

Biopsies from carcinoma tissue and benign control mucosa from head and neck squamous cell carcinoma (HNSCC) patients were used to establish fragment (F)-spheroids in vitro. We have previously shown that autologous monocytes co-cultured with F-spheroids in vitro augment their secretion of monocyte chemotactic protein-1 (MCP-1). Presently, the aims of the present work were to study whether the metabolic activity, secreted products and/or specific receptor/ligand on the surface of the F-spheroids and monocytes are necessary for stimulation of the monocyte MCP-1 secretion upon F-spheroid co-culture. Actinomycin D (1 mug/ml for 24 h) pre-treatment of the F-spheroids abolished the monocyte MCP-1 co-culture response. Co-culture of monocytes and F-spheroids separated by a semi-permeable membrane showed a decreased, but still present, monocyte MCP-1 co-culture response. Conditioned medium from F-spheroids stimulated allogenous monocytes to secrete MCP-1. The addition of glucose or galactose, but not mannose, to co-cultures partially inhibited the monocyte MCP-1 co-culture response. The addition of anti-CD14 antibody diminished the MCP-1 co-culture response. In conclusion, the monocyte MCP-1 co-culture response is dependent on metabolically active spheroids, secreted stimuli, and is augmented by direct contact with F-spheroids, possibly via lectin-like receptors and the CD14 receptor.

Chemokines bind to sulfatides as revealed by surface plasmon resonance

Chemokines bind to sulfated cell surface glycosaminoglycans and thereby modulate signaling mediated by G-protein-coupled seven-transmembrane domain chemokine receptors. Similar to glycosaminoglycans, sulfated oligosaccharides are also exposed on the cell surface by sulfatides, a class of glycosphingolipids. We have now identified sulfated glycosphingolipids (sulfatides) as novel binding partners for chemokines. Using surface plasmon resonance (SPR), the binding of proinflammatory and homeostatic chemokines to glycosphingolipids, in particular sulfatides, was investigated. Chemokines were immobilized while glycosphingolipids or additional phospholipids incorporated into liposomes were applied as soluble analytes. A specific affinity of the chemokines MCP-1/CCL2, IL-8/CXCL8, SDF-1alpha/CXCL12, MIP-1alpha/CCL3 and MIP-1beta/CCL4 to the sulfatides SM4s, SM3, SM2a and SB2, SB1a was detected. No significant interactions with the chemokines were observed for gangliosides, neutral glycosphingolipids or phospholipids. Chemokine receptors have been associated with the detergent-insoluble fraction supposed to contain 'rafts', i.e., glycosphingolipid enriched microdomains of the cell surface. Accordingly, the data suggest that early chemokine receptor signaling may take place in the vicinity of sulfated glycosphingolipids on the cell surface, whereby these sulfatides could modulate the chemokine receptor-mediated cell activation signal.

Localization of thymidine phosphorylase in advanced gastric and colorectal cancer

Thymidine phosphorylase (TP) is known to be more concentrated in human cancer tissues than in adjacent normal tissue based on findings using enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry. However, the ultrastructural localization of TP in cancer tissues has not previously been demonstrated. We investigated the localization of TP in gastric cancer and colorectal cancer tissue by ELISA, immunohistochemistry, and immunoelectron microscopy. Between April 1997 and May 2000, we obtained surgically resected specimens from 42, 46, and 36 cases of advanced gastric, colon, and rectal cancer, respectively. ELISA demonstrated that the TP level was higher in cancer tissues than in adjacent normal tissue. Immunohistochemically, cancer cells were positive for the enzyme in some cases. However, in a number of cases immunopositive inflammatory cells were also present in cancerous tissues. At the electron microscope level, TP was diffusely distributed in the cytoplasm of cancer cells and in the mitochondria of the neutrophil in gastric cancer tissue. In rectal cancer tissues, cytoplasmic granules in macrophages in cancer tissues were immunoreactive for the TP. These findings suggest that TP is produced by macrophages and exists in neutrophils and cancer cells.

Natural killer T cells infiltrate neuroblastomas expressing the chemokine CCL2

CD1d-restricted Valpha24-Jalpha18-invariant natural killer T cells (iNKTs) are potentially important in tumor immunity. However, little is known about their localization to tumors. We analyzed 98 untreated primary neuroblastomas from patients with metastatic disease (stage 4) for tumor-infiltrating iNKTs using TaqMan((R)) reverse transcription polymerase chain reaction and immunofluorescent microscopy. 52 tumors (53%) contained iNKTs, and oligonucleotide microarray analysis of the iNKT(+) and iNKT(-) tumors revealed that the former expressed higher levels of CCL2/MCP-1, CXCL12/SDF-1, CCL5/RANTES, and CCL21/SLC. Eight tested neuroblastoma cell lines secreted a range of CCL2 (0-21.6 ng/ml), little CXCL12 (</=0.1 ng/ml), and no detectable CCL5 or CCL21. CCR2, the receptor for CCL2, was more frequently expressed by iNKT compared with natural killer and T cells from blood (P < 0.001). Supernatants of neuroblastoma cell lines that produced CCL2 induced in vitro migration of iNKTs from blood of patients and normal adults; this was abrogated by an anti-CCL2 monoclonal antibody. CCL2 expression by tumors was found to inversely correlate with MYCN proto-oncogene amplification and expression (r = 0.5, P < 0.001), and MYCN-high/CCL2-low expression accurately predicted the absence of iNKTs (P < 0.001). In summary, iNKTs migrate toward neuroblastoma cells in a CCL2-dependent manner, preferentially infiltrating MYCN nonamplified tumors that express CCL2.

Tumor-associated macrophages: a molecular perspective

The "macrophage balance hypothesis" was proposed in the early 1990s to depict the complex relationship that tumor-associated macrophages (TAM) have with the neoplastic cells of the tumor. TAM represent a prominent component of the mononuclear leukocyte population of solid tumors, which displays an ambivalent relationship with tumors. They originate in the circulation and are recruited to the tumor site by tumor-derived attractants such as chemokines and interact with the tumor cells and preferentially localize at the tumor-host tissue interface, in regions often associated with low oxygen tensions. The tumor microenvironment, including cytokines and hypoxia, regulates the localization and function of TAM. Emerging evidence starts to define the molecular basis for the peculiar functional phenotype of TAM and identifies possible therapeutic targets.

Possible co-regulation of genes associated with enhanced progression of mammary adenocarcinomas

Tumor progression is a multistep process in which alterations in the expression of numerous gene products may give rise to highly malignant cellular variants. In the present study, we analyzed the differential expression of several genes in cellular variants of mammary adenocarcinomas with high or low malignancy potential, which originated in a common ancestor. To assess the generality of our findings, high and low malignancy variants were derived from two different mammary adenocarcinoma cell lines, namely DA3 and CSML cells. Of major importance is the fact that the differences between high- and low-malignancy variants observed in one system of mammary adenocarcinoma cells (DA3 cells) were identically reproduced in the other system of mammary adenocarcinoma cells (CSML cells). The high malignancy variants of tumors both DA3-high and CSML-high (previously called CSML-100), expressed higher levels of factors that induce monocyte migration than the low malignancy DA3-low and CSML-low (previously called CSML-0) variants. In addition, it was found that DA3-high and CSML-high cell variants expressed higher levels of monocyte chemoattractant protein-1 (MCP-1), interleukin-6 (IL-6) and matrix metalloproteinases (MMPs) than the low malignancy variants (DA3-low and CSML-low). These results suggest that MCP-1, IL-6 and MMPs potentially contribute to mammary adenocarcinoma progression and that their expression is regulated by a common pathway. The expression of MCP-1, IL-6 and MMPs in both DA3-high and CSML-high cells was up-regulated by tumor necrosis factor alpha (TNFalpha). The fact that TNFalpha exerted similar effects on the expression of these three factors in both cell systems raises the possibility of a coordinated co-regulation of tumor-promoting factors.

Tumor-associated macrophages in breast cancer

Neoplastic cells form only one part of a complex network of cell types that make up a breast tumor. The normal cell types that make up the nonneoplastic components of tumors include fibroblasts, endothelium, and inflammatory cells, such as tumor associated macrophages (TAMs). TAMs have the potential to carry out both anti- and protumor activities In their antitumor role TAMs can present tumor antigens to cytotoxic T-cells and are capable of being directly cytotoxic to neoplastic cells. Conversely, TAMs are also able to promote tumor growth directly by secreting breast tumor mitogens, such as epidermal growth factor, and indirectly by stimulating tumor angiogenesis and metastasis. Recent studies have indicated that in breast cancers the protumor role of TAMs is dominant, and that TAMs may be executing a "wound healing" type of process in response to stimuli found in the tumor microenvironment, such as hypoxia. As such, TAMs may provide opportunities for future therapeutic interventions.

Paracrine angiogenic loop between head-and-neck squamous-cell carcinomas and macrophages

Angiogenesis, an essential step in the development of neoplasia, is a complex process that involves the interaction of tumor cells with stromal cells. Tumor-associated macrophages (TAMs) can participate in the induction of tumor angiogenesis and are thought to be of prognostic value in some neoplasms. We have investigated how macrophages contribute to angiogenesis in head-and-neck squamous-cell carcinoma (HNSCC) and have found that tumor cells attract monocytes and activate them to secrete angiogenic factors. The attraction of macrophages was due to the secretion of monocyte chemotactic protein-1 and TGF-beta1 by tumor cells, while tumor production of TGF-beta1 was responsible for activating macrophages. In addition, activated macrophages produced cytokines that acted in a paracrine fashion by secreting both TNF-alpha and IL-1, which in turn stimulated tumor cells to secrete increased levels of IL-8 and VEGF. These data demonstrate that TAMs play an important role in the in vivo induction of angiogenesis in HNSCC and suggest that anti-angiogenic therapies for HNSCC and perhaps other neoplasms must include strategies that will block the ability of tumor cells to recruit macrophages into the tumor micro-environment.

Low-Level Monocyte Chemoattractant Protein-1 Stimulation of Monocytes Leads to Tumor Formation in Nontumorigenic Melanoma Cells

Tumors commonly produce chemokines for recruitment of host cells, but the biological significance of tumor-infiltrating inflammatory cells, such as monocytes/macrophages, for disease outcome is not clear. Here, we show that all of 30 melanoma cell lines secreted monocyte chemoattractant protein-1 (MCP-1), whereas normal melanocytes did not. When low MCP-1-producing melanoma cells from a biologically early, nontumorigenic stage were transduced to overexpress the MCP-1 gene, tumor formation depended on the level of chemokine secretion and monocyte infiltration; low-level MCP-1 secretion with modest monocyte infiltration resulted in tumor formation, whereas high secretion was associated with massive monocyte/macrophage infiltration into the tumor mass, leading to its destruction within a few days after injection into mice. Tumor growth stimulated by monocytes/macrophages was due to increased angiogenesis. Vessel formation in vitro was inhibited with mAbs against TNF-alpha, which, when secreted by cocultures of melanoma cells with human monocytes, induced endothelial cells under collagen gels to form branching, tubular structures. These studies demonstrate that the biological effects of tumor-derived MCP-1 are biphasic, depending on the level of secretion. This correlates with the degree of monocytic cell infiltration, which results in increased tumor vascularization and TNF-alpha production.

Scavenger-receptor targeted photodynamic therapy

Covalent conjugation of a photosensitizer to a ligand that specifically recognized and internalized by a cell-surface receptor may be a way of improving the selectivity of photodynamic therapy (PDT). The class A Type-I scavenger receptor of macrophages, which among other ligands recognizes maleylated serum albumin and has a high capacity is a good candidate for testing this approach. Chlorin(e6) was covalently attached to bovine serum albumin to give conjugates with molar substitution ratios of 1:1 and 3:1 (dye to protein), and these conjugates could then be further modified by maleylation. A novel way of purifying the conjugates by acetone precipitation was developed in order to remove traces of unbound dye that could not be accomplished by size-exclusion chromatography. Conjugates were characterized by polyacrylamide gel electrophoresis and thin-layer chromatography. Photosensitizer uptake was measured by target J774 murine macrophage-like cells and nontarget OVCAR-5 human ovarian cancer cells, and phototoxicity was examined after illumination by a 660 nm diode laser by a tetrazolium assay. All of the purified conjugates were taken up by and after illumination killed J774 cells while there was only small uptake and no phototoxicity toward OVCAR-5 cells. The higher dye:protein ratio and maleylation of the conjugates both produced higher uptakes and lower survival ratios in J774 cells. The uptake and phototoxicity by J774 cells were decreased after incubation at 4 degrees C demonstrating internalization, and confocal microscopy with organelle-specific green fluorescent probes showed largely lysosomal localization. Uptake and phototoxicity by J774 cells could both be competed by addition of the scavenger receptor ligand maleylated albumin. These data show that scavenger receptor-targeted PDT gives a high degree of specificity toward macrophages and may have applications in the treatment of tumors and atherosclerosis.

Macrophage migration inhibitory factor in prostatic adenocarcinoma: correlation with tumor grading and combination endocrine treatment-related changes

BACKGROUND

Macrophage migration inhibitory factor (MIF) is a ubiquitary cytokine whose expression has been investigated in tumors, showing a correlation between tumor aggressiveness and production of this protein by neoplastic cells. The aim of our study was to correlate MIF expression with tumor grade (Gleason scoring system) and histopathological changes after combined endocrine treatment (CET) of prostate adenocarcinoma.

METHODS

We analyzed MIF immunoreactivity in 124 paired needle biopsies and radical prostatectomy specimens from 62 prostate cancer patients, of which 20 had been treated with CET.

RESULTS

In untreated prostates, MIF expression significantly correlated with tumor grading, being stronger in low-grade than in high-grade adenocarcinoma. In treated prostates, histopathological changes also correlated with MIF immunoreactivity, but not in a significant manner.

CONCLUSIONS

The results of the current study demonstrated that with histological dedifferentiation, prostate adenocarcinoma cells show a reduced MIF expression. This finding may be the consequence of a reduced MIF synthesis or the result of an enhanced and altered secretion by tumor cells into the surrounding stroma. The consequent abnormal interaction between MIF and environmental factors might influence tumor growth and diffusion. On the other hand, the minor but not significantly reduced MIF expression by tumor cells after CET seems to exclude a hormonal regulation of MIF secretion.

Prognostic value of tumor-associated macrophage count in human bladder cancer

BACKGROUND

We determined the tumor-associated macrophage (TAM) count to investigate its importance in predicting clinical outcome or prognosis in patients with bladder cancer.

METHODS

The TAM count and microvessel count (MVC) were determined immunohistochemically in 63 patients with bladder cancer, including 40 superficial bladder cancers and 23 invasive bladder cancers. To examine the relationship between TAM count and clinical outcome or prognosis in bladder cancer, cystectomy rates, distant metastasis rates, vascular invasion rates and 5 year survival rates were compared between patients with low (< 67) and high (> or = 67) TAM counts.

RESULTS

The TAM count in invasive bladder cancers (154.22+/-11.98) was significantly higher than in superficial bladder cancers (49.05+/-7.76; P<0.0001). The MVC in invasive bladder cancers (71.55+/-10.44) was also significantly higher than in superficial bladder cancers (47.02+/-5.57; P<0.05). There was a positive correlation between TAM count and MVC (r=0.30; P=0.02). Immunohistochemical staining using CD68/horseradish peroxidase monoclonal antibody showed more infiltrating cells in invasive than superficial bladder cancers. Patients with a high TAM count (> or =67) showed significantly higher rates of cystectomy, distant metastasis and vascular invasion than those with a lower TAM count (<67). The 5 year survival rate estimated using the Kaplan-Meier method was significantly lower in patients with a high TAM count than in those with a low TAM count (P<0.0001).

CONCLUSIONS

Our results suggest that determination of TAM count in bladder cancer tissues is of value to predict the clinical outcome or prognosis and to select appropriate treatment strategies in patients with bladder cancer.

Platelet-derived endothelial cell growth factor/thymidine phosphorylase expression correlated with tumor angiogenesis and macrophage infiltration in colorectal cancer

To clarify whether platelet-derived endothelial cell growth factor/thymidine phosphorylase (PD-ECGF/TP) expression in both tumor cells and stromal cells has independent or synergistic effects on tumor angiogenesis and progression and to explore a possible regulator for PD-ECGF/TP expression, immunohistochemical staining was conducted on 148 specimens of colorectal cancer. The microvessel count was significantly correlated with the extent of PD-ECGF/TP expression. Macrophage infiltration in tumors with positive TP was significantly higher than in tumors with negative TP (P < 0.001). The Cox model showed that PD-ECGF/TP expression was an independent prognostic factor, although the microvessel count had a stronger value in determining the patient prognosis.

Monocyte chemotactic and activating factor/monocyte chemoattractant protein in bronchoalveolar lavage fluid from patients with atopic asthma and chronic bronchitis. Relationship to lung function tests, bronchial hyper-responsiveness and cytology of bronchoalveolar lavage fluid

Monocyte chemotactic and activating factor/monocyte chemoattractant protein (MCAF/MCP1) is a member of beta (C-C) subfamily of chemokines. The biological roles played by MCAF/MCP1 in a number of inflammatory and non-inflammatory disease states is not well known. Several studies have confirmed that inflammation is present in the airways of subjects with atopic asthma (AA) and in chronic bronchitis (CHB). The aim of the current study was to examine associations among MCAF/MCP1 and bronchoalveolar lavage fluid (BALF) cells and disease severity as measured by airway caliber and bronchial hyperresponsiveness in patients with AA and CHB. Thirty-two patients with AA, 32 patients with CHB and 14 patients of a control group took part in this study. ELISA test was used to assess MCAF/MCP1 in BALF. The levels of MCAF/MCP1 (mean +/- S.E.M.) were 107 +/- 15.8 pg/ml in patients with AA, 393.4 +/- 105.9 pg/ml in CHB and 36.4 +/- 10.9 pg/ml in the control group (P < 0.05). Significant correlations with clinical parameters were found in both group of patients with disease. In conclusion, MCAF/MCP1 possesses proinflammatory properties and their biological effect can in part account for the persistance of inflammation in the bronchial mucosa of AA and CHB.

Regulation of monocyte chemoattractant protein-1 expression in adult human non-neoplastic astrocytes is sensitive to tumor necrosis factor (TNF) or antibody to the 55-kDa TNF receptor

Infiltration of the central nervous system (CNS) by monocytes is a characteristic of many non-malignant disease processes, although the signals regulating such traffic are unclear. Tumor necrosis factor (TNF) and other inflammatory cytokines have been shown to elicit production of monocyte chemoattractant activity in glioma cells, but the regulation of such activity in non-neoplastic adult astrocytes has not been examined. We previously observed that TNF constituted a proliferative signal for non-neoplastic adult human astrocytes in vitro involving the 55-kDa TNF receptor. In the present study, we demonstrate that TNF exposure enhances the expression of monocyte chemoattractant protein-1 (MCP-1) mRNA and functional monocyte chemoattractant activity in non-neoplastic astrocytes. Results indicated that MCP-1 mRNA expression was maximal within 3 h, and was further augmented by the protein synthesis inhibitor cycloheximide (CY). Antibody (htr-9) directed against the 55-kDa TNF receptor also elicited MCP-1 mRNA expression while antibody to the 75-kDa TNF receptor (utr-1) was ineffective. Secretion of monocyte chemoattractant activity was significantly greater in TNF- or htr-9-treated astrocytes than in utr-1-treated or untreated controls; activity was abolished by treatment with antibody to MCP-1. These findings suggest that non-neoplastic adult human astrocytes may contribute to CNS inflammatory responses by mediating recruitment of peripheral blood monocytes.

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.

Cytokines and proteases in invasive processes: molecular similarities between inflammation and cancer

Tumor-derived serine proteinases and metalloproteinases have been associated with invasion and metastasis of cancer cells. Leukocytes, particularly monocytes/macrophages and neutrophils, actively synthesize and store these proteolytic enzymes. The production by tumor cells of chemotactic factors that attract white blood cells raises questions that are important for the basic researcher as well as the clinical scientist. Are the proteinases, which have the capacity to dissolve the extracellular matrix and by this solubilization promote cell migration, the same in tumor cells as in normal cells? Is the production of chemotactic factors by tumor cells a coincident epiphenomenon of the malignant state or a selective way to parasitize the host? Does the early attraction of leukocytes to the tumor site contribute to early host defense against cancer? Does our knowledge about mechanisms of action of cytokines have implications for therapy of the cancer patient? Recent experimental data give hints to the answers to these questions and make it possible to deduce a fundamental model of cytokine mediated proteolysis in tissue remodelling.

Gene expression and cDNA cloning identified a major basic protein constituent of bovine seminal plasma as bovine monocyte-chemoattractant protein-1 (MCP-1)

P6 is one of the major basic proteins of bovine seminal plasma. Using cell-free translation of poly(A)+RNA from bovine seminal vesicle tissue and monospecific anti-P6-IgGs, we show that P6 is a secretory product of the seminal vesicles. Immunohistochemical experiments supported this finding. Immunoscreening of a lambda gt11 cDNA library derived from seminal vesicle poly(A)+RNA furnished a number of positive cDNA clones, from which clone pH42 was characterized by sequencing. The partial amino acid sequence of a CNBr-fragment of P6 permitted identification of the reading frame of clone pH42 encoding the precursor protein of P6. The P6 precursor contains a signal peptide of 23 amino acids followed by the mature P6 sequence of 76 amino acid residues. The cDNA sequence of pH42 was 80% homologous with that of the human monocyte-chemoattractant protein-1 (hMCP-1). The respective amino acid sequences for the precursor molecules are 72% identical. Northern analysis of seminal vesicle poly(A)+RNA using pH42 as probe probe identified a 0.9-kb P6 mRNA. Stimulation of P6 mRNA expression by phytohemagglutinin in bovine peripheral mononuclear leukocytes suggests that P6 is identical to bovine MCP-1.

Characterization of monocyte chemotactic protein-1 binding to human monocytes

Monocyte chemotactic protein-1 (MCP-1) stimulates chemotaxis of peripheral blood monocytes. In order to understand the biologic basis of this specific activity, binding studies of 125I-MCP-1 were undertaken. MCP-1 showed saturable binding to monocytes. Scatchard analysis of the monocyte binding data indicate that there are approximately 1,600 high affinity binding sites per monocyte with a Kd = 1.1 nM. Studies with synthetic peptides constructed according to the MCP-1 amino acid sequence indicate that a synthetic peptide, MCP-1[13-35], stimulates monocyte migration and competes with native MCP-1 for binding sites. Inhibition of MCP-1 binding was tested with chemotactic connective tissue proteins. No inhibition of MCP-1 binding was observed with either collagen, elastin-derived peptides or fibronectin. These results identify a single class of unique high affinity MCP-1 binding sites that are likely to recognize a peptide domain on MCP-1 which include the amino acids within the region, 13-35.