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  • 1
    ISSN: 1432-0851
    Keywords: Liposomal therapy ; Fibrosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have recently begun a phase II trial in patients with osteosarcoma who developed pulmonary metastases during adjuvant chemotherapy or who presented with pulmonary metastases that persisted despite chemotherapy. Eligible patients were rendered free of visible disease by surgery. Liposome-encapsulated muramyl tripeptide phosphatidylethanolamine (MTP-PE, CGP 19835A lipid) (2 mg/m2) was infused twice weekly for 3 months. In five patients, a single tumor nodule recurred within 6 weeks after completion of therapy. These lesions were resected and submitted for pathological examination. Tissue specimens obtained after therapy were compared to those obtained before therapy. All the patients showed a histological change in the characteristics of the pulmonary tumors. In three patients, peripheral fibrosis surrounded the tumor and inflammatory cell infiltration and neovascularization were present. This is in contrast to central necrosis, with viable peripheral tumor cells and no inflammatory response observed in lesions resected following chemotherapy. In a fourth case, evidence of early fibrotic changes was found. This and the fifth case showed a change in malignant characteristics, from high grade before liposomal therapy to low grade after therapy. The present study provides evidence for a biological effect of liposomal MTP-PE.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0851
    Keywords: Adriamycin ; L-MTP-PE ; Cytokine ; Monocyte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Liposomal muramyl tripeptide phosphatidylethanolamine (L-MTP-PE) is a biological agent in phase I and II trials for osteosarcoma and melanoma. Its mechanism of action has been linked to its ability to activate monocyte tumoricidal function and to stimulate monocyte production of tumor necrosis factor (TNF) and interleukins(IL)-1, −6, and −8. Our ultimate goal is to combine L-MTP-PE with chemotherapy. The purpose of this study was to determine whether doxorubicin (Adriamycin) interfered with the ability of L-MTP-PE to activate monocyte cytokine production. Human monocytes were cultured with or without 5–500 ng/ml of Adriamycin for 3 h and washed before being exposed to 2 μg/ml L-MTP-PE for 16 h. Cultured supernatants were collected and assayed for TNF, IL-1, IL-6, and IL-8. The messenger RNA expression of IL-1α, IL-1β, TNFα, IL-6, and IL-8 was quantified with northern blot analysis. Adriamycin did not suppress the upregulation of any of these cytokines. We concluded that combination therapy with L-MTP-PE and Adriamycin is feasible and that this combination warrents further investigation in a clinical setting.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0851
    Keywords: Liposome-encapsulated muramyl tripeptide ; MCAF ; mRNA, monocyte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Liposome-encapsulated muramyl tripeptide phosphatidylethanolamine (L-MTP-PE) is a novel immune modulator that is now under investigation against metastatic melanoma and osteosarcoma. We have already reported that L-MTP-PE induced monocyte-mediated tumoricidal activity and up-regulation of the tumor necrosis factor and interleukin-1 (IL-1) in vivo and in vitro. We now demonstrate that L-MTP-PE also induces monocyte chemotactic and activating factor (MCAF) mRNA expression at both the transcriptional and post-transcriptional levels. Monocyte chemotactic activity was also present in the supernatants of L-MTP-PE-stimulated cells. In monocytes, the increased expression of MCAF was induced rapidly (by 2 h) but was short-lived. By 4 h, MCAF mRNA had decreased to background level. We found no change in MCAF mRNA levels in lymphocytes exposed to L-MTP-PE. We therefore conclude that L-MTP-PE selectively up-regulates MCAF expression in monocytes and that MCAF may play a role in the tumoricidal and immune-stimulating activity of L-MTP-PE.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0851
    Keywords: Liposomal MTP-PE ; Activated monocytes ; Ibuprofen ; Cytokine production
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The purpose of this study was to determine the effects of ibuprofen on the ability of liposome-encapsulated muramyl tripeptide phosphatidylethanolamine (L-MTP-PE) to activate human blood monocytes in vitro. We undertook these experiments because the major toxic side-effects following L-MTP-PE infusion, fever and chills, could be prevented when ibuprofen was given orally immediately before L-MTP-PE infusion. It was therefore important to determine whether ibuprofen interfered with the macrophage-activation properties of L-MTP-PE. Peripheral blood monocytes were isolated from normal donors, then incubated with L-MTP-PE in the presence or absence of ibuprofen. The cytotoxic properties of the monocytes were assessed by a radioisotope-release assay against A375 cells. Ibuprofen at dose levels of 40 µg/ml suppressed the generation of the cytotoxic phenotype but did not interfere with the killing process once the cells were activated. Interleukin-1 (IL-1) and tumor necrosis factor α (TNFα) production, as well as the mRNA expression of these cytokines, was suppressed by 40 µg/ml ibuprofen. Since IL-1 and TNF play a crucial role in the cytotoxic function of monocytes, these findings may explain the mechanism by which ibuprofen inhibited the generation of the cytotoxic phenotype by L-MTP-PE. By contrast, ibuprofen dose levels up to 10 µg/ml had no effect on the generation of monocyte-mediated cytotoxicity by L-MTP-PE and no effect on the production, secretion, or mRNA expression of TNF and IL-1. Therefore, we concluded that if ibuprofen is to be used to control the side-effects of L-MTP-PE, blood levels of up to 10 µg/ml are desirable. In two of three patients, we determined that an oral dose of 200 mg given immediately before L-MTP-PE infusion could achieve these desired blood levels.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Cancer immunology immunotherapy 37 (1993), S. 203-208 
    ISSN: 1432-0851
    Keywords: Anti-TNF ; IL-1 ; Liposomal MTP-PE ; Monocytes ; TNF
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The purpose of this study was to examine the mechanisms by which liposome-encapsulated muramyl tripeptide phosphatidylethanolamine (L-MTP-PE) stimulates monocytes to produce tumor necrosis factor (TNF) and interleukin-1 (IL-1). We have previously shown that secretion of TNF protein occurred 2–4 h following incubation of monocytes with L-MTP-PE and that this stimulation of TNF production was associated with an increase in TNF mRNA. Increased intracellular interleukin-1α (IL-1α) and IL-1β were not detected until 8 h after exposure to L-MTP-PE. To determine whether TNF played a role in the stimulation of IL-1 production by L-MTP-PE, normal human monocytes were incubated with L-MTP-PE or medium in the presence or absence of anti-TNF or anti IL-1α plus anti IL-1β. Enhanced expression of IL-1α and IL-1β mRNA was inhibited at 4 h but not 24 h when monocytes were incubated with L-MTP-PE plus anti-TNF compared with L-MTP-PE alone. By contrast, enhanced expression of TNF mRNA wasnot inhibited at any time when monocytes were incubated with L-MTP-PE and anti-IL-1α plus anti-IL-1β. These data indicate that the up-regulation of IL-1 seen in monocytes following L-MTP-PE exposure may be due in part to the production of TNF. The up-regulation of TNF, however, appears to be independent of IL-1 production.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-0851
    Keywords: Key words: Liposome-encapsulated muramyl tripeptide – MCAF – mRNA, monocyte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Liposome-encapsulated muramyl tripeptide phosphatidylethanolamine (L-MTP-PE) is a novel immune modulator that is now under investigation against metastatic melanoma and osteosarcoma. We have already reported that L-MTP-PE induced monocyte-mediated tumoricidal activity and up-regulation of the tumor necrosis factor and interleukin-1 (IL-1) in vivo and in vitro. We now demonstrate that L-MTP-PE also induces monocyte chemotactic and activating factor (MCAF) mRNA expression at both the transcriptional and post-transcriptional levels. Monocyte chemotactic activity was also present in the supernatants of L-MTP-PE-stimulated cells. In monocytes, the increased expression of MCAF was induced rapidly (by 2 h) but was short-lived. By 4 h, MCAF mRNA had decreased to background level. We found no change in MCAF mRNA levels in lymphocytes exposed to L-MTP-PE. We therefore conclude that L-MTP-PE selectively up-regulates MCAF expression in monocytes and that MCAF may play a role in the tumoricidal and immune-stimulating activity of L-MTP-PE.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-0851
    Keywords: Locomotion TIL ; Immunotherapy MTP-PE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The ability of the lymphocytes to move through the interstitium is obligatory to the immune response. We previously showed that tumor-infiltrating lymphocytes (TIL) from human melanoma and renal cell carcinoma demonstrate a dramatic decrease in their spontaneous locomotion through three-dimensional collagen gel when compared with peripheral blood lymphocytes (PBL) and lymph node lymphocytes. To determine if this decrease is caused by contact with tumor cells, or mediated through certain diffusible factors, we examined the effects of autologous tumor cells on the locomotion of PBL in a model system where tumor cells were separated from lymphocytes by a 3-mm layer of gelled collagen. After 21–22 h incubation in chamber slides, locomotion distances were assessed in the presence and absence of tumor and normal cells. In the presence of tumor cells. PBL from 14 of 18 patients displayed substantial (466.5±2.7 μm compared to control 568.9±10.9 μm,P〈0.001), loss of motility. Inhibition was more prominent in melanoma patients than in renal cell carcinoma patients. Thus the impaired locomotion previously observed in TIL was at least partially due to the presence of tumor. The locomotion of TIL was restored in four of five melanoma patients treated with liposome-encapsulated muramyltripeptide-phosphatidylethanolamine (L-MTP-PE). Furthermoe, in six of seven examined L-MTP-PE-treated patients, an increase in intrinsic PBL locomotion during the first month of the therapy was observed. These results suggest that the environment of the tumor is not conducive to locomotion of advancing lymphocytes and the therapeutic intervention may ameliorate the loss of lymphocytic infiltration.
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  • 8
    ISSN: 1432-0851
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The characteristics of the binding of human monocytes to tumor cells were studied by a newly developed microassay. First, we determined the kinetics and optimal conditions of the binding. Monocytes recognized and bound to tumor cells very rapidly within 10–20 min of cellular interaction. Binding was also more efficient at 37°C suggesting that active metabolism of monocytes is required. Second, we determined that selective binding of monocytes to cells with tumorigenic phenotypes occurs. For this purpose, lymphocytic leukemia cell lines versus normal lymphocytes, and tumorigenic versus nontumorigenic hybrids from the same parental lines were compared as the targets of the binding assay. In both cases, neoplastic cells were selectively bound by monocytes. Although tumor cells were bound rapidly and selectively by monocytes, initial recognition and binding did not necessarily lead to subsequent tumor cell lysis. This is based on the observation that some tumorigenic parental and hybrid lines were avidly bound by monocytes yet not subsequently killed in a cytotoxicity assay.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Cancer immunology immunotherapy 12 (1982), S. 191-196 
    ISSN: 1432-0851
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-0851
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The purpose of these studies was to determine whether stimulated human lymphocytes produce lymphokines distinct from IFNγ, that can activate human blood monocytes to lyse tumor cells. We undertook this investigation because of the controversy concerning whether MAF and IFNγ are the same molecule. Crude lymphokine preparations prepared from normal human mononuclear cells incubated with Con A and rich in MAF activity also contained 1000 U/ml IFNγ as measured by the virus neutralization assay. However, the induction of tumoridical activity in monocytes by the lymphokine preparation could be dissociated from the IFNγ activity, based on the following data: (1) Heat treatment (100 °C for 2 min) removed the antiviral activity of the lymphokine yet did not diminish its MAF-like activity when measured in a 72 h cytotoxicity assay against 125I IUdR-labeled human A375 melanoma cells. (2) Likewise, treatment of this lymphokine preparation with a twofold excess of anti-IFNγ antibody neutralized antiviral activity but once again had no effect on its ability to activate monocyte tumoricidal function. In contrast, both heat treatment and anti-IFNγ antibody abolished monocyte activation by equivalent units of human recombinant IFNγ. Taken together, these data suggest that there is a molecule(s) distinct from IFNγ which can activate human monocytes for tumoricidal function. Furthermore, this dissociation of MAF and IFNγ activity was dependent on the use of a long-term (72 h) assay, since activation of tumoricidal activity in an 18–24 h assay appeared to be attributable solely to IFNγ.
    Type of Medium: Electronic Resource
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