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W Fiers

Publications and source records attributed to W Fiers.

At least 271 records · Page 15Linked to original sources
PubMed1987

Nuclear magnetic resonance analysis of tumor necrosis factor-induced alterations of phospholipid metabolites and pH in Friend leukemia cell tumors and fibrosarcomas in mice.

The alterations induced on the pool sizes of five phospholipid metabolites, glycerol 3-phosphorycholine, glycerol 3-phosphorylethanolamine, phosphorylcholine, sn-glycerol 3-phosphate, and choline were studied by nuclear magnetic resonance (NMR) spectroscopy in murine tumors injected with recombinant murine tumor necrosis factor (TNF). Solid tumors were obtained by s.c. injection of either Friend leukemia cells (clones 3C1-8 and 745) in DBA/2 mice or murine fibrosarcoma cells (HeN4) in C3H/HeN mice. After tumor nodules had developed, TNF or bovine serum albumin was injected intratumorally. Treatment of both tumors with TNF resulted in a marked inhibition of tumor growth. 31P-NMR analyses of Friend leukemia cell tumors (and tissue extracts), 6 h after injection of TNF, showed: (a) a 1.5- to 3.5-fold decrease in the pool sizes of glycerol 3-phosphorylcholine and glycerol 3-phosphorylethanolamine; (b) a 7- to 8-fold increase of sn-glycerol 3-phosphate; (c) a 2- to 3.5-fold decrease of phosphorylcholine; (d) an alkaline shift (0.2 units) in intratumoral pH. Similar metabolic alterations occurred in TNF-treated HeN4 fibrosarcoma. 1H-NMR analyses of Friend leukemia cell tumor extracts also indicated, 6 h after tumor injection with TNF: (a) elevated choline levels (9X); (b) a 19-fold increase in the ratio [choline]/[phosporylcholine]; (c) elevated (1.4X) levels of lactic acid; and (d) a 1.6-fold decrease in the [taurine]/[glycine] ratio. The results are interpreted in the light of possible alterations in the activity of enzymes controlling the de novo biosynthesis and catabolism of phospholipids. We concluded that NMR spectroscopy can be a useful means to monitor the level of some phospholipid precursors and/or derivatives as early markers of therapeutic efficacy in intact neoplastic tissues.

Animals↗
PubMed1987

Evidence for tumour necrosis factor/cachectin production in cancer.

Labile tumour-necrosis-factor-like (TNF) activity was detected by means of an enzyme-linked immunosorbent assay in 50% of 226 freshly obtained serum samples from cancer patients with active disease. In contrast, only 3% of 32 samples from normal subjects and 18% of 39 samples from cancer patients with no clinically evident disease were positive for this factor, with low levels of activity. Greater proportions of serum samples from patients with ovarian or oat-cell carcinoma were positive (69% and 63%) than those from patients with lymphoma (26%). RNA preparations from peripheral-blood mononuclear cells and solid tumours were probed with TNF complementary DNA; evidence of TNF messenger RNA was found in 8 of 11 samples of peripheral-blood mononuclear cells from cancer patients, but only 1 of 8 normal subjects, and in 2 of 6 colorectal tumours. As yet the inducing stimulus and the clinical significance of TNF production in cancer are not understood.

Adult↗
PubMed1987

Anti-tumor activity of recombinant mouse tumor necrosis factor (TNF) on colon cancer in rats is promoted by recombinant rat interferon gamma; toxicity is reduced by indomethacin.

The activity and toxicity of rMuTNF, alone or combined with rat recombinant interferon gamma (rRIFN gamma), was tested in inbred WAG rats bearing a weakly immunogenic colon adenocarcinoma (CC531). The tumor was implanted s.c. or under the renal capsule. A single i.v. injection of 10 micrograms of rMuTNF in non-tumor bearers was lethal in 3 to 5 hr, whereas 2 micrograms was not. Doses of 1 microgram rMuTNF were well tolerated when given daily for one week. The most prominent toxic feature was hemorrhagic colitis which could be alleviated when rMuTNF was preceded by i.p. administration of 10 mg/kg indomethacin. Three intralesional injections of 10 micrograms rMuTNF on days 0, 10 and 15 into s.c. tumors (diameter 1-1.5 cm) led to a moderate retardation of growth in 20% of the cases. Combined with 10(5) units of rRIFN gamma, which on its own had no effect, the overall response rate (arrest of tumor growth or regression) was 50%. Two out of 20 tumors treated intralesionally with rMuTNF and rRIFN gamma regressed. The subrenal capsule assay was used to study the possible interference of indomethacin with the anti-tumor activity of rMuTNF. Tumor cubes of 6-8 mg were implanted under the renal capsule; the test was evaluated by weighing. Treatment with 10 mg indomethacin alone on days 0, 2 and 4 had no effect (40 +/- 8 mg vs. 48 +/- 13 mg in controls) whereas 2 micrograms of rMuTNF on the same days resulted in significant tumor inhibition (24 +/- 7 mg, p less than 0.001). The combined administration of 2 micrograms of rMuTNF and indomethacin had an effect similar to that of rMuTNF alone (25 +/- 9 mg). Under protection of indomethacin the rMuTNF dose was increased from 2 micrograms to 10 micrograms. However, this did not lead to further improvement of the results.

Adenocarcinoma↗
PubMed1987

Membrane interleukin 1 induction on human endothelial cells and dermal fibroblasts.

Human endothelial cells and dermal fibroblasts both expressed a membrane-associated interleukin 1 (IL-1) activity when stimulated with either recombinant tumor necrosis factor (TNF) or recombinant lymphotoxin but stimulated endothelial cells expressed significantly more membrane IL-1 per cell than did fibroblasts. Lipopolysaccharide induced membrane IL-1 activity on endothelial cells but not fibroblasts. Interferon-gamma treatment of endothelial cells and fibroblasts had no direct effect on membrane IL-1 expression and little effect when used as a pretreatment for TNF or lipopolysaccharide stimulation. Endothelial cell membrane IL-1 activity was induced within 24 hr of culture with TNF or lipopolysaccharide, and increased up to 72 hr of incubation. Antibodies raised against human monocyte-derived IL-1 species neutralized the membrane IL-1 activity of TNF-stimulated endothelial cells. Both absorption studies and neutralization with specific sera indicated that endothelial cell membrane IL-1 is structurally related to IL-1 alpha. Endothelial cells expressed both IL-1 beta mRNA in response to TNF, lymphotoxin, and recombinant IL-1 species, as detected by Northern blot analysis. These studies demonstrate that endothelial cells can be activated to express a cell-surface IL-1 activity which is structurally, as well as functionally, related to the secreted form of IL-1.

Cell Membrane↗
PubMed1987

Therapeutic potential of tumor necrosis factor-alpha and gamma-interferon in experimental human ovarian cancer.

We have studied the activity of recombinant human gamma-interferon and recombinant human tumor necrosis factor alpha against four human ovarian cancer i.p. xenografts OS, LA, HN, and DO derived from primary tumor material. In the OS xenograft all control mice died by 42 days and therapy starting 7 days after tumor cell injection with 5 X 10(4) units recombinant human gamma-interferon or 1 microgram recombinant human tumor necrosis factor alpha alone had no significant effect on cumulative survival in three separate experiments. However, a combination of the two agents resulted in 85% cumulative survival at 150 days. This combination therapy also significantly increased survival of mice treated as late as 21 days after tumor cell injection. In the LA xenograft (where control mice were all dead by 23 days) therapy with either agent alone, or a combination, more than doubled survival time of mice. In the HN xenograft all control mice were dead at 22 days whereas either therapy alone or in combination gave +85% cumulative survival at 100 days. In a fourth xenograft, DO, survival of mice in the combination therapy group was significantly increased. Thus these two biological therapies, alone or in combination, show significant activity against human ovarian cancer cells.

Animals↗
PubMed1987

Induction of an activation antigen on postcapillary venular endothelium in human skin organ culture.

We studied the effects of the immune mediators interleukin 1, interleukin 2, tumor necrosis factor, immune interferon, and lipopolysaccharide on the expression of the endothelial activation antigen recognized by the murine monoclonal antibody H4/18 in short term organ cultures of newborn foreskins. No endothelial staining was detectable before culture. Interleukin 1, tumor necrosis factor, and lipopolysaccharide each induced 2+ to 3+ H4/18 staining of microvascular endothelium at 6 hr. Combining mediators produced additive (3+ to 4+) effects, and reactivity was lost or markedly diminished by 24 hr. Incubation with culture medium alone resulted in 1+ to 2+ H4/18 staining at 6 hr, and medium conditioned by cultured foreskins, but not mock-conditioned medium, could induce H4/18 binding in cultured human umbilical vein endothelial cells. The spontaneous expression of microvascular staining in the foreskins was markedly inhibited by cyclosporin A, but not polymyxin B sulfate or dexamethasone; cyclosporin A did not inhibit induction of staining by exogenous mediators. Both light level and immunoultrastructural studies demonstrated H4/18 expression to be associated predominantly with postcapillary venular endothelial cells of the superficial vascular plexus. We conclude that microvascular endothelium of skin can undergo activation in response to exogenous and endogenous cytokines, with the greatest changes occurring in those portions of the vessels most involved in leukocyte and lymphocyte trafficking.

Animals↗
PubMed1987

Activation of cultured human endothelial cells by recombinant lymphotoxin: comparison with tumor necrosis factor and interleukin 1 species.

Recombinant human lymphotoxin (LT) was compared with recombinant human tumor necrosis factor (TNF) for direct actions on cultured human endothelial cells (HEC). At equivalent half-maximal concentrations (based on L929 cytotoxicity units) LT and TNF each caused rapid and transient induction (peak 4 to 6 hr) of an antigen associated with leukocyte adhesion (detected by monoclonal antibody H4/18), a rapid but sustained increased expression (plateau 24 hr) of a lymphocyte adhesion structure (ICAM-1), a gradual (plateau 4 to 6 days) increase in expression of HLA-A,B antigens, and gradual (4 to 6 days) conversion of HEC culture morphology from epithelioid to fibroblastoid, an effect enhanced by immune interferon (IFN-gamma). Induction of H4/18 binding by maximal concentrations of LT or TNF could not be augmented by addition of the other cytokine, and 24 hr pretreatment with LT or TNF produced hyporesponsiveness to both mediators for reinduction. H4/18 binding can be transiently induced by tumor-promoting phorbol esters. Pretreatment with either LT or TNF also fully inhibited induction of H4/18 binding by phorbol ester, whereas phorbol ester pretreatment only variably and partially inhibited reinduction by LT or TNF. These actions of LT on endothelium shared with TNF may serve in vivo to promote lymphocyte and inflammatory leukocyte adhesion and transendothelial migration. Recombinant human interleukin 1 species (IL 1 alpha and IL 1 beta) shared many of the actions of LT and TNF and were indistinguishable from each other. However, IL 1 species could be distinguished from LT/TNF by their relative inability to enhance HLA-A,B expression, by their ability to augment H4/18 binding caused by maximally effective concentrations of LT or TNF, and by their inability to inhibit reinduction of H4/18 binding by LT or TNF. In contrast to the actions of LT or TNF, pretreatment with IL 1 alpha or IL 1 beta only partially inhibited induction of H4/18 binding by phorbol ester, and phorbol ester pretreatment consistently, albeit partially, inhibited induction by IL 1 species. These studies suggest that activated T cells through the secretion of LT can in turn activate the local endothelial lining so as to promote homing and extravasation of inflammatory cells. Furthermore, these LT actions can be augmented or complemented by other locally produced mediators such as IFN-gamma or IL 1.

Antibodies, Monoclonal↗
PubMed1987

Effects of tumour necrosis factor on human tumour xenografts in nude mice.

Recombinant human tumour necrosis factor (rHuTNF) when injected intraperitoneally into nude mice bearing subcutaneous tumour xenografts (breast and bowel) had no significant antitumour activity (six different tumours were tested). The same dose administered locally at the tumour site resulted in complete regression and cure of the majority of tumours. Macroscopic evidence of tumour necrosis was rarely seen but microscopically a peritumoral cuff of host inflammatory cells surrounded the dying tumour cells within four days of the start of therapy. The combination of rHuTNF (i.p.) with recombinant human gamma-interferon (rHuIFN-gamma) (i.p.) led to significant tumour inhibition in only one of three xenografts tested. Combination of rHuTNF (i.p.) and HuIFN-alpha (s.c.) resulted in significant inhibition in all of three xenografts tested. Human ovarian tumours were grown in the peritoneal cavity of nude mice. The biological behaviour of this cancer closely resembled the human disease, the xenografts growing as solid tumours and/or ascites. When rHuTNF or rHuIFN-gamma were given intraperitoneally at the time of tumour cell injection most mice survived, whereas control mice died in 4-8 weeks. Once the disease was established (seven days or more after injection) either agent alone was ineffective. In the combined results of three experiments with one xenograft, with a total of 21 mice in each group, cumulative survival at 154 days was 0% for control mice and 5% and 15% for mice treated with 1 microgram/day rHuTNF or 5 X 10(4) U/day rHuIFN-gamma, respectively, when therapy was started seven days after tumour cell injection. Combining the two agents led to a cumulative survival of 85%. This combination cured 40% of mice by 21 days after tumour cell injection. With a further two ovarian cancer xenografts, the combination of rHuTNF and rHuIFN-gamma produced a significant survival advantage.

Animals↗
PubMed1987

Structure-function relationship of tumour necrosis factor and its mechanism of action.

We have cloned the cDNAs of both human and mouse TNF and expressed them to high efficiency in Escherichia coli. Many transformed cell lines are sensitive to the cytotoxic action of TNF, especially in the presence of gamma-interferon, whereas normal cells either are unaffected or respond mitogenically. A number of human-mouse chimeric TNF genes have been constructed and expressed. All show biological activity but none of the chimeric proteins is neutralized by monoclonal antibodies to TNF. TNF has potent antitumour activity in nude mice carrying human xenografts or in mice bearing syngeneic tumours. In some systems direct effects can be demonstrated (in combination with species-specific gamma-interferon) but in others TNF acts indirectly. Combination of TNF with cytostatic drugs can also be effective in curing in vivo. The major limitation of the use of TNF is its toxicity. On many cell types TNF has an action similar to interleukin 1 (IL-1). At least some of the secondary, intracellular events may be identical for the two effectors. A possible mechanism of action of TNF is the release and metabolism of polyunsaturated fatty acids, which would explain the synthesis of prostaglandins and leukotrienes by many cell types after TNF treatment. The activation of the phospholipase can be blocked by corticoids. Some protease inhibitors protect cells from TNF-induced cytotoxicity but the target of these inhibitors has not been identified. Several genes are switched on by TNF (and by IL-1), including the gene for the 26 kDa protein recently identified as B cell stimulation factor 2. Events preceding death in rats include hypothermia, hypotension, acidosis and hypoglycaemia. All these effects can be largely eliminated by indomethacin pretreatment, with a resulting improvement in survival. As indomethacin does not inhibit the cytotoxic action of TNF on malignant cells it may form the basis for improved treatment protocols.

Animals↗
PubMed1987

Specific suppression elicited by EL4 lymphoma cells in syngeneic mice. Specificity includes self-antigens on EL4.

In vivo, subclones derived from EL4 lymphoma cells generate suppressor T lymphocytes specific for anti-EL4 immune responses. Spleen cells of EL4-sensitized C57BL/6 mice down-regulate the in vitro induction of EL4-specific cytolytic T lymphocytes (CTL). In addition, EL4-sensitized spleen cells interfere with the antigen response of two T lymphocyte clones. These recognize, in an H-2b context, a self-antigen on spleen cells that is also expressed by transformed cells, including EL4. The simultaneous anti-self and anti-EL4 specificity of the helper and suppressor activities suggests, therefore, that they are the product of an in vivo autoimmune reaction to EL4. The anti-self suppression might aim to re-establish self-tolerance, at the same time down-regulating responses against immunogenic epitopes that are co-expressed with the self-antigen on the EL4 cells. This agrees well with our observation that suppressor T cells, apparently elicited by suppressogenic epitopes on non-immunogenic EL4 subclones, down-regulate the CTL response elicited by immunogenic EL4 subclones. The additional self-specificity of this suppression indicates that the suppressogenic epitopes at least in part represent EL4 self-antigens.

Animals↗
PubMed1987

DNA fragmentation and cytotoxicity caused by tumor necrosis factor is enhanced by interferon-gamma.

Recombinant human tumor necrosis factor (rhuTNF) induced DNA fragmentation in sensitive cell lines. This fragmentation was similar to that caused by lymphotoxin-containing cytotoxic T cell culture supernatants. The percentage of DNA cleaved correlated with the degree of cell growth inhibition shown by individual cell lines. DNA fragmentation was first seen after 12 h treatment, and increased slowly with time. The presence of 100 microM ZnSO4 inhibited the rhuTNF-induced DNA cleavage in MCF-7 cells. Recombinant interferon-gamma (rhuIFN-gamma) did not induce DNA cleavage, although it reduced the growth of all the cell lines used in this study. However, it interacted with rhuTNF to produce a doubling in the percentage of DNA fragmentation, and increased cytotoxicity in rhuTNF-sensitive cell lines. Pretreatment with rhuIFN-gamma for 1 h prior to rhuTNF treatment also enhanced DNA fragmentation and cell killing.

Cells, Cultured↗
PubMed1987

Modulation of expression of class II histocompatibility antigens by secretion of a cellular inhibitor in K562 leukemic cells.

In this report we show that it is possible to induce the expression of HLA-DR antigens on K562 cells, previously reported to be unresponsive to interferon-gamma (IFN-gamma). However, only low cell concentrations and a high dose of IFN-gamma allowed the induction of HLA-DR antigens. Furthermore, the recombinant glycosylated IFN-gamma is 100-fold more efficient than the unglycosylated form. This induction of HLA-DR antigens on K562 was not related to a stage of differentiation or to the presence of cells subsets specifically sensitive to IFN-gamma, since repeated sorting of K562 HLA-DR-positive and negative cells did not lead to the selection of a cell subset with a different potential of induction for HLA-DR. The difficulty in obtaining induction is due to the production of a soluble endogenous inhibitor of proteic nature, whose action is not restricted to the K562 cell line since it operates also on both epithelial and fibroblastic cells. Treatment of normal human epithelial and fibroblastic cells with conditioned medium from K562 cultures caused a marked decrease in the expression of HLA class II antigens (DR and DP) induced by IFN-gamma (10,000 U/ml), but had no effect on cell growth; however, it also affected expression of HLA class I antigens. This inhibition is not mediated by prostaglandin or an IFN-alpha or IFN-beta-dependent mechanism. Production of this inhibitor by pluripotent human leukemic cells could cause an unbalance in the complex control exerted by the immunological system during hematopoietic differentiation or leukemic progression.

Antibodies, Monoclonal↗
PubMed1987

Recombinant tumor necrosis factor can induce interleukin 2 receptor expression and cytolytic activity in a rat x mouse T cell hybrid.

Tumor necrosis factor (TNF), an endotoxin-induced macrophage monokine, is known for its cytotoxic and cytostatic effect on some tumor cell lines. Here we show that highly purified recombinant TNF, in combination with interleukin 2 (IL2), can induce IL2 receptor expression and cytolytic activity in a rat x mouse T cell hybrid (PC60). Previously, it was shown that IL1 had a similar effect on PC60 cells. The ability of TNF to co-induce IL2 receptor expression suggests that it may play a role in the activation of certain lymphoid effector cells. This observation augments the growing list of biological activities attributed to TNF.

Animals↗
PubMed1987

B cell growth modulating and differentiating activity of recombinant human 26-kd protein (BSF-2, HuIFN-beta 2, HPGF).

The human "26-kd protein' is a secreted glycoprotein expressed, for example, in (blood) leukocytes, in epithelial cells treated with various inducers, but most strongly in interleukin-1 (IL-1)-treated fibroblasts. After finding it has antiviral and 2-5A synthetase-inducing activity, one group of authors called this protein IFN-beta 2. However, recently the full-length 26-kd cDNA sequence was shown to be identical with that of a B-cell-differentiating lymphokine called BSF-2, and another report suggested that the 26-kd protein could support the growth of some transformed murine B cell lines. To define its biological activities, we expressed the recombinant 26-kd protein by translating in Xenopus laevis oocytes a pure, synthetic chimeric mRNA containing the 26-kd protein coding region surrounded by Xenopus laevis beta-globin untranslated regions. A similar construction, but containing the HuIFN-beta cDNA coding region, was used to produce HuIFN-beta by the same procedure. Both recombinant glycoproteins were secreted, glycosylated, and their amounts were measured by [35S]methionine incorporation by the oocyte. Here we show that the recombinant 26-kd protein exhibits a high growth factor activity when assayed on an IL-HP1-dependent murine B cell hybridoma (sp. act. approximately 2 X 10(8) U/mg) as well as a potent differentiating activity on human CESS cells (sp. act. approximately 5 X 10(7) U/mg). While rHuIFN-beta was inactive in the latter two assays, it had the expected antiviral activity of 1-5 X 10(8) U/mg. The parallel recombinant 26-kd protein preparations had no detectable antiviral activity (i.e. a maximal specific activity of 1-3 X 10(2) U/mg, if any). The 26-kd protein is thus clearly an interleukin, and considering the confusing nomenclature now in use, this factor may better be renamed "interleukin 6'.

Animals↗
PubMed1987

The effect of recombinant human tumour necrosis factor on growth and macromolecular synthesis of human epithelial cells.

We have studied the effect of recombinant human tumour necrosis factor (rHuTNF) on growth and macromolecular synthesis in a range of normal and transformed epithelial cell types. Tumour necrosis factor did not affect the growth of normal human mammary epithelial cells, but its growth-inhibitory action on the SV40-transformed human mammary epithelial cell line HBL-100 increased with passage number in association with a progression of malignant phenotype. However, of two lines derived from nude mouse tumours of HBL-100 lines, one, HBLT-12, did not respond to rHuTNF, and the other, HBLT-11 showed some growth stimulation by high dose rHuTNF. Macromolecular synthesis in HBLT-11 was not affected by rHuTNF. The breast cancer cell lines MCF-7 and BT20 were sensitive to the cytotoxic effects of rHuTNF. In MCF-7 a gradual decrease in RNA and DNA synthesis occurred over 48 h, ending with an accumulation of cells in S and G2 phase of the cell cycle and cell death. The addition of alpha- or gamma-interferon increased, but did not accelerate the cytotoxicity of rHuTNF.

Breast Neoplasms↗
PubMed1987

Alloinduced suppression and cytotoxicity: two functions of a single cell.

Using different experimental approaches we here show that the suppression and cytotoxicity generated during a one-way mixed lymphocyte culture (MLC) are mediated by a single cell population, in this case the cytotoxic T lymphocyte (CTL). Results of limiting-dilution analysis of cells from a 4-day MLC demonstrate the coexpression of both functions and argue against the existence of a separate suppressor cell population that regulates the in vitro alloresponse. The suppressive quality of CTL is also exemplified in cells with a clonal origin, such as cloned cytotoxic T lymphocytes and the mouse X rat hybridoma PC60. Further experiments demonstrate that this suppression is not primarily mediated through lysis of the stimulator cells, and studies in the PC60 model suggest that lysis and suppression may have different induction requirements.

Animals↗
PubMed1987

Gene cloning and structure--function relationship of cytokines such as TNF and interleukins.

The genes for a number of proteins, potentially useful in cancer therapy and collectively called "biological response modifiers", have been cloned and expressed in micro-organisms in recent years. These recombinant proteins, which are now available in pure form in nearly unlimited quantities, include interferons, interleukins and cytotoxins such as Tumor Necrosis Factor (TNF) and lymphotoxin. Most often the human gene has been cloned and expressed, with view to possible applications in medicine, but usually the mouse equivalent gene was also characterized in order to carry out syngeneic animal model experiments. TNF is selectively toxic for many transformed cell lines, either alone or in combination with interferon or inhibitors of RNA or protein synthesis. Cells sensitive to the cytotoxic action of TNF and cells unaffected by it nonetheless usually carry about an equal number of TNF receptors; hence it is the secondary, intracellular signal which makes the difference between a transformed cell and a normal, diploid cell. TNF can induce a number of different genes in a variety of cells; for example, endothelial cells express a surface antigen responsible for adherence of leucocytes. Another gene which is induced by TNF is interleukin 6 (also called 26 kDa protein or BSF-2). This interleukin, IL-6, is a growth and differentiation factor for B cells as well as for T cells; it is responsible for functions previously ascribed to hepatocyte-stimulating factor, but has no interferon activity. The toxic action of TNF on tumor cells must involve the release of arachidonic acid as phospholipase inhibitors block the TNF-induced effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗