Impaired tumoricidal function of alveolar macrophages from patients with non-small cell lung cancer

Dendritic Cell Vaccination in Non-Small Cell Lung Cancer: Remodeling the Tumor Immune Microenvironment

Non-small-cell lung cancer (NSCLC) remains one of the leading causes of death worldwide. While NSCLCs possess antigens that can potentially elicit T cell responses, defective tumor antigen presentation and T cell activation hinder host anti-tumor immune responses. The NSCLC tumor microenvironment (TME) is composed of cellular and soluble mediators that can promote or combat tumor growth. The composition of the TME plays a critical role in promoting tumorigenesis and dictating anti-tumor immune responses to immunotherapy. Dendritic cells (DCs) are critical immune cells that activate anti-tumor T cell responses and sustain effector responses. DC vaccination is a promising cellular immunotherapy that has the potential to facilitate anti-tumor immune responses and transform the composition of the NSCLC TME via tumor antigen presentation and cell-cell communication. Here, we will review the features of the NSCLC TME with an emphasis on the immune cell phenotypes that directly interact with DCs. Additionally, we will summarize the major preclinical and clinical approaches for DC vaccine generation and examine how effective DC vaccination can transform the NSCLC TME toward a state of sustained anti-tumor immune signaling.

Analysis of Interleukin-2/Interleukin-2 Receptor System in Advanced Non-Small-Cell Lung Cancer

Aims and background

The purpose of the study was to investigate the IL-2/IL-2 receptor system in patients with advanced non-small-cell lung cancer (NSCLC).

Patients and methods

Sera from 40 subjects and 80 patients with stage III and IV NSCLC were assayed for soluble interleukin-2 receptor (sIL-2R) and interleukin-2 (IL-2) by the enzyme-linked immunosorbent assay. Circulating CD25+ cells were analyzed by flow cytoflorimetry. The data were related to clinical status by comparing the levels of slL-2R and IL-2 at diagnosis and during the treatment.

Results

The mean slL-2R concentrations of the NSCLC patients were significantly higher than the control population (P=0.0001); the patients with metastatic disease had significantly higher levels than those with locally advanced disease (P=0.02). No correlation was seen between circulating CD25+ cells and slL-2R levels. Disease progression was associated with an increase in slL-2R levels and a decline in IL-2; the sIL-2R/IL-2 ratio showed a gradual increase with tumor progression.

Conclusions

Our study demonstrates in a large series of patients that in advanced NSCLC there is an imbalance of the IL-2/IL-2 receptor system. Furthermore, circulating slL-2R levels and the sIL-2R/IL-2 ratio may be useful as markers of disease activity and treatment response, suggesting a potential prognostic value.

Alveolar Macrophage Polarisation in Lung Cancer

The role of alveolar macrophages in lung cancer is multifaceted and conflicting. Alveolar macrophage secretion of proinflammatory cytokines has been found to enhance antitumour functions, cytostasis (inhibition of tumour growth), and cytotoxicity (macrophage-mediated killing). In contrast, protumour functions of alveolar macrophages in lung cancer have also been indicated. Inhibition of antitumour function via secretion of the anti-inflammatory cytokine IL-10 as well as reduced secretion of proinflammatory cytokines and reduction of mannose receptor expression on alveolar macrophages may contribute to lung cancer progression and metastasis. Alveolar macrophages have also been found to contribute to angiogenesis and tumour growth via the secretion of IL-8 and VEGF. This paper reviews the evidence for a dual role of alveolar macrophages in lung cancer progression.

Interactions between rnacrophage cytokines and eicosanoids in expression of antitumour activity

Cytokines and eicosanoid products of macrophages play an essential role in expression of antitumour activity of macrophages either in a cell-to-cell contact system between the effector and the target cell or as cell-free soluble products. In this review the relationship between three main monokines, namely TNF-α, IL-1 and IL-6 and the interrelationship between these monokines and eicosanoids (PGE₂, PGI₂, LTB₄, LTC₄) in their production and in expression of antitumour activity is discussed. Emphasis is given to the effect of tumour burden on production of the monokines and of the eicosanoids and on the production of these compounds by the tumour cells. Finally, the therapeutic implications drawn from animal studies and clinical trials is discussed.

Smac mimetic compounds potentiate interleukin-1beta-mediated cell death

Smac mimetic compounds (SMCs) potentiate TNFα-mediated cancer cell death by targeting the inhibitor of apoptosis (IAP) proteins. In addition to TNFα, the tumor microenvironment is exposed to a number of pro-inflammatory cytokines, including IL-1β. Here, we investigated the potential impact of IL-1β on SMC-mediated death of cancer cells. Synergy was seen in a subset of a diverse panel of 21 cancer cell lines to the combination of SMC and IL-1β treatment, which required IL-1β-induced activation of the NF-κB pathway. Elevated NF-κB activity resulted in the production of TNFα, which led to apoptosis dependent on caspase-8 and RIP1. In addition, concurrent silencing of cIAP1, cIAP2, and X-linked IAP by siRNA was most effective for triggering IL-1β-mediated cell death. Importantly, SMC-resistant cells that produced TNFα in response to IL-1β treatment were converted to an SMC-sensitive phenotype by c-FLIP knockdown. Reciprocally, ectopic expression of c-FLIP blocked cell death caused by combined SMC and IL-1β treatment in sensitive cancer cells. Together, our study indicates that a positive feed-forward loop by pro-inflammatory cytokines can be exploited by SMCs to induce apoptosis in cancer cells.

Macrophage-derived IL-1beta stimulates Wnt signaling and growth of colon cancer cells: a crosstalk interrupted by vitamin D3

Tumor associated macrophages mediate the link between inflammation and cancer progression. Here we showed that macrophage-derived soluble factors induce canonical Wnt signaling in colon cancer cells and promote their growth. Tumor cells induced the release of IL-1β from macrophages, which induced phosphorylation of GSK3β, stabilized β-catenin, enhanced TCF-dependent gene activation, and induced the expression of Wnt target genes in tumor cells. Neutralization experiments using anti IL-1β specific antibodies, or silencing of IL-1β in THP1 macrophages, revealed that IL-1β was required for macrophages to induce Wnt signaling and to support the growth of tumor cells. Constitutive activation of STAT1 in THP1 macrophages was essential for the induction of IL-1β and thus for the activation of β–catenin signaling in tumor cells.

Vitamin D₃, an effective chemopreventive agent, interrupted this crosstalk by blocking the constitutive activation of STAT1 and the production of IL-1β in macrophages, and therefore- in a vitamin D receptor dependent manner- inhibited the ability of macrophages to activate Wnt signaling in colon carcinoma cells. Our data therefore established that vitamin D₃ exerts its chemopreventive activity by interrupting a cross-talk between tumor epithelial cells and the tumor microenvironment.

IL-8 induces exocytosis of arginase 1 by neutrophil polymorphonuclears in nonsmall cell lung cancer

Arginase 1 (ARG1) inhibits T-cell proliferation by degrading extracellular arginine, which results in decreased responsiveness of T cells to CD3/TCR stimulation. In humans, ARG1 is stored in inactive form within granules of polymorphonuclear neutrophils (PMNs) and gets activated on release. We studied the role of PMNs-related ARG1 activity in nonsmall cell lung cancer (NSLC), in which tumor-infiltrating lymphocytes showed reduced proliferation in response to CD3/TCR triggering. Patients with NSCLC had increased ARG1 plasma levels as compared to healthy controls. Furthermore, immunohistochemistry showed that tumor-infiltrating PMNs display reduced intracellular ARG1, in comparison to intravascular or peritumoral PMNs, suggesting a role of tumor microenvironment in ARG1 release. Indeed, supernatants of NSCLC cell lines induced exocytosis of ARG1 from PMNs. All (4/4) NSCLC cell lines and all (7/7) CD14- cell samples from NSCLC expressed interleukin (IL)-8 mRNA, whereas TNFalpha mRNA was expressed by 1 cell line and by 2 tumor specimens. Furthermore, all NSCLC cell lines secreted immunoreactive IL-8, albeit at different levels. IL-8 was as effective as TNFalpha in triggering ARG1 release and the 2 cytokines acted synergistically. Secreted ARG1 was biologically active and catabolized extracellular arginine. The supernatant of IL-8 gene-silenced NSCLC cells did not mediate ARG1 release by PMNs. Altogether these findings demonstrate a role of IL-8 in ARG1 exocytosis by PMNs and indicate that, due at least in part to IL-8 secreted by NSCLC cells, PMNs infiltrating NSCLC release ARG1. This phenomenon could contribute to local immune suppression.

Uncovering the immune tumor microenvironment in non-small cell lung cancer to understand response rates to checkpoint blockade and radiation

The study of immunology has led to breakthroughs in treating non-small cell lung cancer (NSCLC). The recent approval of an anti-PD1 checkpoint drug for NSCLC has generated much interest in novel combination therapies that might provide further benefit for patients. However, a better understanding of which combinations may (or may not) work in NSCLC requires understanding the lung immune microenvironment under homeostatic conditions and the changes in that microenvironment in the setting of cancer progression and with radiotherapy. This review provides background information on immune cells found in the lung and the prognostic significance of these cell types in lung cancer. It also addresses current clinical directions for the combination of checkpoint inhibitors with radiation for NSCLC.

Effect of IFN-gamma stimulation on expression of intercellular adhesion molecule-1 (ICAM-1) on alveolar macrophages in patients with non-small cell lung cancer

An impairment of in vitro cytotoxicity and tumoricidal function of alveolar macrophages (AMs) in patients with lung cancer was reported in a number of studies. The aim of our study was to evaluate the expression of intercellular adhesion molecule-1 (ICAM-1) on AMs after stimulation with interferon-gamma (IFN-gamma) in patients with non-small cell lung cancer (NSCLC). The study was performed in 13 patients with NSCLC, 6 patients with various nonmalignant pulmonary diseases, and 6 healthy volunteers. AMs were isolated from bronchoalveolar lavage fluid (BALF) by adherence and then cultured with or without IFN-gamma for 24 h. The expression of ICAM-1 on AMs was analyzed by flow cytometry. Stimulation with IFN-gamma caused increased expression of ICAM-1 on AMs in all studied groups (p < 0.05). The degree of the increase in ICAM-1 expression on AMs after IFN-gamma stimulation was significantly lower in patients with NSCLC compared with healthy volunteers (p = 0.002) or the other patients (p = 0.022). The results suggest impaired reactivity of ICAM-1 expression on AMs after stimulation with IFN-gamma in patients with NSCLC, which might be involved in functional defects of AMs in patients with NSCLC.

Characterization of macrophage subpopulations in colon cancer using tissue microarrays

AIMS

To determine the pattern of macrophage infiltration in colon cancers and its correlation with clinicopathological characteristics.

METHODS AND RESULTS

Colon cancers from 100 patients were arrayed into a tissue microarray (TMA). Four cores per tumour were taken: three from the invasion front (IF) and one from the tumour surface (TS). Macrophages were quantified by immunohistochemistry with antibodies to the PG-M1, KP-1, MRP8, MRP14 and MRP8/14 antigens. The number of macrophages was significantly higher in the TS cores than in the IF cores and both tumour sites showed a higher number of macrophages than the normal mucosa. The number of macrophages decreased in higher stage tumours. The different tumour-associated macrophage (TAM) subpopulations were positively correlated with each other.

CONCLUSIONS

The increased number of macrophages in cancers compared with normal colon mucosa indicates that macrophages are attracted to the tumour site. However, decreasing macrophages in higher stage colon cancers suggest that this attraction decreases with tumour progression.

Modulation of macrophage differentiation and activation by decoy receptor 3

Decoy receptor 3 (DcR3) is a soluble receptor of the tumor necrosis factor receptor superfamily and is readily detected in certain cancer patients. Recently, we demonstrated that DcR3.Fc-treated dendritic cells skew T cell responses to a T helper cell type 2 phenotype. In this study, we further asked its ability to modulate CD14+ monocyte differentiation into macrophages induced by macrophage-colony stimulating factor in vitro. We found that DcR3.Fc was able to modulate the expression of several macrophage markers, including CD14, CD16, CD64, and human leukocyte antigen-DR. In contrast, the expression of CD11c, CD36, CD68, and CD206 (mannose receptor) was not affected in the in vitro culture system. Moreover, phagocytic activity toward immune complexes and apoptotic bodies as well as the production of free radicals and proinflammatory cytokines in response to lipopolysaccharide were impaired in DcR3.Fc-treated monocyte-derived macrophages. This suggests that DcR3.Fc might have potent, suppressive effects to down-regulate the host-immune system.

Surfactant strengthens the inhibitory effect of C-reactive protein on human lung macrophage cytokine release

In this study we investigated the effect of acute-phase levels of C-reactive protein (CRP) on cytokine production by pulmonary macrophages in the presence or absence of pulmonary surfactant. Both human alveolar and interstitial macrophages as well as human surfactant were obtained from multiple organ donor lungs. Precultured macrophages were stimulated with LPS alone or together with IFN-gamma in the presence or absence of CRP, surfactant, and combinations. Releases of TNF-alpha and of IL-1beta to the medium were determined. We found that CRP could modulate lung inflammation in humans by decreasing the production of proinflammatory cytokines by both alveolar and interstitial macrophages stimulated with LPS alone or together with IFN-gamma. The potential interaction between CRP and surfactant phospholipids did not overcome the effect of either CRP or surfactant on TNF-alpha and IL-1beta release by lung macrophages. On the contrary, CRP and pulmonary surfactant together had a greater inhibitory effect than either alone on the release of proinflammatory cytokines by lung macrophages.

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.

Decrease in K-ras p21 and increase in Raf1 and activated Erk 1 and 2 in murine lung tumors initiated by N-nitrosodimethylamine and promoted by 2,3,7,8-tetrachlorodibenzo-p-dioxin

Recent evidence suggests that K-ras protooncogene protein p21 may have a tumor-suppressive role in the context of development of lung adenocarcinoma. Levels of K-ras p21, raf-1, mitogen-activated protein kinases Erk 1 and 2, the phosphorylated-activated forms of Erk 1 and 2 (Erk 1P and 2P), and proliferating cell nuclear antigen (PCNA) were measured by immunoblotting in mouse lung tumors (5 to 9 mm in size) caused by N-nitrosodimethylamine (NDMA) and in control lungs. In tumors compared with normal lung, cell membrane-associated K-ras p21 was significantly decreased and cytosolic K-ras p21 increased. Total, membrane, and cytosolic raf-1 and Erk 1P and 2P were increased in tumors compared with normal lung. A single dose of 5 nmol/kg 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) given after NDMA resulted in a significant 2.4-fold increase in tumor multiplicity. A significantly greater decrease in membrane-associated K-ras p21 and increase in total and membrane associated raf-1 occurred in the NDMA/TCDD tumors compared with the NDMA-only tumors. PCNA levels increased in tumors, a finding confirmed by immunohistochemistry, and correlated with tumor size after NDMA/TCDD treatment but not after NDMA only. The increase in raf-1 in the tumors was confirmed by immunohistochemistry, which also revealed an increase in raf-1-positive alveolar macrophages specifically associating with tumors from the earliest stages. These results suggest a possible tumor-suppressive function for K-ras p21 in lung and a positive role for raf-1 and Erk 1/2 in lung tumorigenesis. TCDD may promote tumors by contributing to downregulation of K-ras and stimulation of raf-1.

In vitro secretion of cytokines and prostaglandin-E2 by monocytes from lung cancer patients

Monocytes (MO) from cancer patients present functional abnormalities, such as an altered secretion of soluble factors. In the present study, our aim was to evaluate the levels of interleukin-1beta (IL-1beta), tumour necrosis factor-alpha (TNF-alpha) and prostaglandin-E2 (PGE2) secreted in vitro by MO from lung cancer patients (LCP), spontaneously or after stimulation with lipopolysaccharide (LPS). Results showed that cytokine secretion was higher for MO from LCP than for MO from healthy controls, while in the 25% of the patients analysed, an absence of response to LPS treatment was found.

Tumor cytotoxicity of peritoneal macrophages and peripheral blood monocytes from patients with ovarian, endometrial, and cervical cancer

The purpose of this study was to compare the cytotoxic capacity of peritoneal macrophages (PM) and peripheral blood monocytes (PBM) from patients with ovarian, endometrial, and cervical cancers after in vitro activation with gamma interferon (IFN-gamma) and lipopolysaccharide (LPS). Peritoneal macrophages were obtained from ascites or peritoneal washings and peripheral blood monocytes via peripheral venipuncture from 58 patients: 17 with ovarian, 19 with endometrial, and 10 with cervical cancers. PBM and PM from 12 patients with nonmalignant gynecologic conditions served as controls. Cytotoxicity was assessed by the ability of PBM and PM to lyze Cr51-labeled Chang hepatoma cells. Activated peripheral blood monocytes of ovarian and endometrial cancer patients and peritoneal macrophages from ovarian cancer patients were significantly more cytotoxic than those from nonactivated controls. Activated PBM and PM from cervical cancer and PM from endometrial cancer did not demonstrate increased cytotoxicity compared to nonactivated controls. There was no significant correlation of the cytotoxicity with grade, stage, differentiation or age of the cancers. These in vitro data would suggest that ovarian cancer and possibly endometrial cancer should receive further evaluation and consideration of cytokine-based and/or adoptive cellular immunotherapy.

Detection of a factor released by L5178Y lymphoblasts that inhibits mouse macrophage-activation induced by lipopolysaccharides

BACKGROUND

Several factors inhibit cellular immune response by deactivating macrophages, but very few, such as those described here, prevent macrophage activation.

METHODS

Ascites liquid from 12-day-old BALB/c mice bearing 5178Y lymphoma tumors was collected, and cell-free ascites liquid (CFAL) was separated from lymphoblasts. The supernatant (S1) was obtained from the homogenized and centrifuged lymphoblasts. Then, macrophage cultures containing 0.2 x 10(6) cells from lymphoma-bearing or healthy mice were added to 10 microL of CFAL or S1, plus 5 micrograms of lipopolysaccharides (LPS)/mL, 40 U interferon-gamma or a blend of both. Macrophages were incubated with CFAL or S1 prior to or after adding the activators to investigate whether any of the previously mentioned lymphoma fractions inhibited macrophage activation or whether they deactivated them. The effect of CFAL or S1 was estimated as the diminution of the amount of nitric oxide released by the experimental macrophage cultures with respect to controls (activated macrophages treated with none of the lymphoma fractions).

RESULTS

LPS, IFN-gamma, and the LPS/gamma blend activated macrophages from both lymphoma-bearing and healthy mice. None of the lymphoma fractions deactivated macrophages. CFAL, but not S1, inhibited the macrophage activation, i.e., the percentage of inhibition of nitric oxide releasing 76.7% and 78.1% in macrophages from healthy and lymphoma-bearing mice, respectively. In addition, CFAL was unable to inhibit the macrophage-activation effect of IFN-gamma or the LPS/IFN-gamma blend.

CONCLUSIONS

Mouse L5178Y lymphoma releases a factor that in vitro inhibits the macrophage activation induced by LPS, but not by IFN-gamma controls.

Cytokine repertoire during maturation of monocytes to macrophages within spheroids of malignant and non-malignant urothelial cell lines

Terminal maturation of human blood monocytes to macrophages (MAC) in vivo is believed to be important for the morphology, antigen expression and functional activity of the resulting MAC population. This process is modulated by the specific tissue micro-environment to which blood monocytes migrate upon leaving the vasculature. Tumor-associated macrophages (TAM) are a special type of MAC, and little is known about the modulating capacity of the tumor environment on monocyte-to-MAC differentiation. By co-culturing 3-dimensional multicellular spheroids (MCS) of the urothelial-bladder-carcinoma cell lines J82 and RT4 with human monocytes/MAC we generated TAM in vitro. For comparison, monocytes/MAC were co-cultured with the non-tumorigenic urothelial cell line HCV29. The effects on monocyte differentiation were analyzed, particularly with respect to cytokine release. Monocyte maturation was modulated within the tumor spheroid dependent upon the tumor cell type. Monocytes co-cultured with MCS of the poorly differentiated J82 carcinoma spontaneously produced high amounts of IL-1beta and IL-6, but only low amounts of TNF-alpha, which could be further increased by the addition of LPS. This cytokine pattern is characteristic for monocytes and remained constant for up to 8 days in J82-MCS co-cultures. However, in RT4-MCS and HCV29-MCS co-cultures, the initial cytokine pattern changed and after 8 days corresponded well to that of MAC differentiated in vitro without tumor contact. In addition to functional parameters, we analyzed the morphology of J82-MCS-TAM and found that they displayed a monocyte-like morphology. Our data indicate that (1) tumor cells can influence monocyte-to-MAC differentiation, giving rise to TAM with monocyte-specific phenotypic properties; and (2) this capacity is dependent on the type of tumor cell.

Multicellular spheroids: a three-dimensional in vitro culture system to study tumour biology

The growth of tumour cells as three-dimensional multicellular spheroids in vitro has led to important insights in tumour biology, since properties of the in vivo-tumour such as proliferation or nutrient gradients, can be studied under controlled conditions. While this review starts with an update of recent data on spheroid monocultures, especially concerning tumour microenvironment and therapeutic modalities, the main emphasis is put on the spectrum of heterologous cultures which have evolved in previous years. This type of culture includes tumour cell interaction with endothelial, fibroblast or immunocompetent cells. The relation of the spheroid culture model to other types of three-dimensional culture and our critical evaluation and presentation of the technical aspects of growing and analysing spheroids are included in the text. These topics are chosen to help the experimental pathologist design experiments with tumour spheroids and to stimulate discussion.

Augmentation of impaired tumoricidal function in alveolar macrophages from lung cancer patients by cocultivation with allogeneic, but not autologous lymphocytes

It has been reported that the in vitro development of tumoricidal function in alveolar macrophages from lung cancer patients is reduced significantly when compared to that in peripheral blood monocytes from the same patients or alveolar macrophages from control patients. In the present investigation, a method for potentiating the development of tumoricidal function in alveolar macrophages from lung cancer patients is described. This method, which relies on priming the macrophages with purified, allogeneic peripheral blood lymphocytes from normal donors, could not be demonstrated when autologous lymphocytes from lung cancer patients were used in the priming coculture. The augmentation of tumoricidal function appears to be mediated by one or more soluble factors, since supernatants from cocultures of alveolar macrophages and allogeneic peripheral blood lymphocytes could enhance the cytotoxic function of freshly obtained alveolar macrophages. Furthermore, it appears that NK cells are necessary for this effect, since depletion of CD56+/CD57+ cells from allogeneic lymphocytes eliminated their capacity to enhance alveolar macrophage cytotoxic function. The augmentation of cytotoxic function elicited in alveolar macrophages by this method was not associated with changes in the secretion of tumor necrosis factor alpha, or interleukin 1 beta.

Modulation of tumoricidal function in alveolar macrophages from lung cancer patients by interleukin-6

Previous studies have demonstrated that alveolar macrophages from lung cancer patients are impaired in their ability to develop tumoricidal function when stimulated by activators such as interferon gamma + lipopolysaccharide. However, these same macrophages have been shown to develop significant tumoricidal function when precultured with macrophage-depleted allogeneic peripheral blood lymphocytes from normal donors, an effect that was lost by the elimination of natural killer cells from the allogeneic lymphocyte population. In the present study, the effect of each activation condition on the expression of mRNA for interleukin-1 alpha (IL-1 alpha), IL-1 beta, tumor necrosis factor alpha (TNF alpha) and IL-6 was determined using reverse transcription/polymerase chain reaction. The results show that the non-permissive activation condition is associated with the expression of mRNA for IL-6 while the permissive activation condition is not. Antibodies against IL-6 were subsequently shown to permit the development of tumoricidal function in alveolar macrophages stimulated with interferon gamma + lipopolysaccharide while IL-6 protein was shown to inhibit the stimulatory action of allogeneic lymphocytes on the development of tumoricidal function in the same alveolar macrophages. Neither the permissive (i.e. allogeneic lymphocyte stimulation) nor the non-permissive (i.e. interferon gamma + lipopolysaccharide) activation condition had any effect on the capacity of alveolar macrophages from lung cancer patients to express mRNA for IL-1 alpha, IL-1 beta or TNF alpha. These results show that IL-6 can regulate the ability of alveolar macrophages from lung cancer patients to be stimulated by interferon gamma + lipopolysaccharide to develop significant tumoricidal function. They also show that allogeneic lymphocytes have the capacity to down-regulate IL-6 mRNA synthesis by alveolar macrophages thereby permitting the development and/or expression of macrophage tumoricidal function.

High and low dose rate irradiation have opposing effects on cytokine gene expression in human glioblastoma cell lines

Effects of radiation on five cytokine expressing human glioblastoma cell lines were studied. In comparison to unirradiated controls, IL-1 beta and IL-6 mRNAs were generally reduced after low (LDR, 1.0 cGy/min) and very low (VLDR, 0.35 cGy/min) dose rate irradiation. In contrast, high (HDR, 200 cGy/min) and intermediate (IDR, 4.1 cGy/min) dose rates increased steady-state levels of IL-1 beta and IL-6 mRNAs. The surviving fraction was generally inversely proportional to the dose rate; however, these glioma cells were unusually susceptible to LDR. In the two cell lines tested, IDR was less cytotoxic than either HDR or LDR irradiation. Although cytokine gene expression had no clear effect on radiation survival in vitro, autologous cytokines could be important to radiation response in vivo by affecting immune response, tumour stroma, vasculature or surrounding tissues. Adjusting dose rates to account for inverse dose rate effects and altered gene expression may be a useful strategy in optimising radiation therapy of glioblastomas.

Subcutaneously implanted tumour: an hypothesized novel approach to individualized immunotherapy for lung carcinoma

A novel approach to immunotherapy for the treatment of lung carcinoma is hypothesized. If a lung tumour removed at operation is implanted subcutaneously within a Millipore chamber in that patient, then a local immune response may be induced. It is suggested that this subcutaneously induced immune response could improve the prognosis of the underlying tumour either of its own accord or by its use as an adoptive immunotherapy. Spread of the tumour locally would be prevented by containment within the Millipore chamber. The hypothesis has been supported by experimental observations from a pilot study.

Three-dimensional co-culture of human monocytes and macrophages with tumor cells: analysis of macrophage differentiation and activation

Here we report on an experimental system for generating TAM in vitro by culturing human MO and MO-derived macrophages (MAC) within 3-dimensional multicellular tumor spheroids (MCS). MO as well as MO-derived MAC migrate into tumor spheroids and spread throughout the entire spheroid within 16 hr. In contrast, fibroblast-spheroids were not infiltrated. The regular expression of MAC maturation-associated antigens on infiltrating MO was suppressed within MCS of the undifferentiated bladder carcinoma line J82 with regard to carboxypeptidase M (CPM), MAX.3 antigen and CD105. However, MAC within spheroids of highly differentiated papillary RT4 cells failed only the single antigen CD51, whereas MAC expressed the complete maturation-associated phenotype within non-tumorigenic HCV29 spheroids. Interestingly, the suppressive effect of J82 carcinoma cells could only be observed in 3-dimensional but not in monolayer cultures. The J82-MCS induced suppression of CPM and MAX.3 expression was only seen to be operative on infiltrating blood MO: MO first differentiated for 2 days and subsequently co-cultured with J82-MCS showed normal expression of MAX.3 and CPM within the spheroid. Besides the modulation of MAC phenotype, the cytokine response of intraspheroidal MAC was analyzed: upon co-culture MO secreted high IL-1beta and IL-6 but low amounts of TNF-alpha as compared to MAC. This MO typical cytokine pattern remained constant for up to 8 days in culture, again indicating a disturbed MO to MAC maturation within tumor spheroids. In conclusion, a 3-dimensional interaction with tumor cells in vitro results in significant changes in the phenotype and function of the spheroid-associated MO and MAC.

Fresh colorectal tumor cells isolated from individual patients differ in their susceptibility to monocyte mediated cytotoxicity

Studies on monocyte/macrophage mediated cytotoxicity usually pertain to the use of cell lines that are liable to antigenic and structural changes. Therefore we compared monocyte mediated cytotoxicity against colorectal tumor cell lines (WiDR, HT29, SW620, and SW948) with fresh colorectal tumor cells from patients. Fresh tumor cells were isolated from surgical specimens by a short enzymatic treatment (Collagenase/DNAse). Monocytes were obtained from one healthy donor. Cytotoxicity was determined using the MTT-assay. Fresh colorectal tumor cells displayed a similar differential susceptibility to cytotoxic monocytes as cell lines. Cytotoxicity against fresh tumor cells ranged from 4.9% to 50.4% at E/T ratio 5 (n = 9). Activation of monocytes with Interferon-gamma (100 U/ml) induced an increase of 6.2% +/- 1.6 (n = 4, P = 0.06). In this study we demonstrate monocyte mediated cytotoxicity against colorectal tumor cells isolated from individual patients. This may be important in view of the development of adoptive immunotherapy and cell-directed immunotherapy.

Suppression of the development of tumoricidal function in gamma interferon-treated human peripheral blood monocytes by lipopolysaccharide: the role of cyclooxygenase metabolites

Bacterial lipopolysaccharide (LPS) is generally regarded as one of the most potent macrophage activators. Thus, LPS has been used as an obligatory second signal to stimulate macrophage cytotoxic function against a wide array of bacterial and neoplastic targets. In this study, however, we define conditions under which LPS can suppress the development of cytotoxic function in normal human peripheral blood monocytes. When monocytes were treated with a priming dose of gamma interferon (gamma-INF), followed 18-24 hr later by a triggering dose of LPS, significant cytotoxic function developed. However, when monocytes were treated with even minimal amounts of LPS during priming with interferon, the development of cytotoxic function following stimulation with a second, triggering dose of LPS was virtually abolished. This effect could be produced from 0 to 14 hr following the addition of gamma-INF. The inhibition of monocyte cytotoxicity which was produced by LPS treatment during priming was dose dependent and could not be overcome by modifying either the priming dose of gamma-IFN or the triggering dose of LPS. The suppression was largely overcome, however, by treatment with the cyclooxygenase inhibitor, indomethacin. The possibility that LPS-induced suppression of monocyte cytotoxicity was mediated by products of the cyclooxygenase pathway was supported further in this study by demonstrating that LPS stimulated the production of significant amounts of prostaglandin E2 (PGE2) from monocytes and that this was facilitated by gamma-IFN. In kinetics studies, it appeared that LPS suppression of monocyte activation was correlated temporally with a heightened sensitivity to suppression by exogenously added PGE2, a condition which was reduced greatly by the end of the priming phase.(ABSTRACT TRUNCATED AT 250 WORDS)