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J van der Bosch

Publications and source records attributed to J van der Bosch.

At least 19 recordsLinked to original sources
PubMed2002

TSST-1 induces Th1 or Th2 differentiation in naïve CD4+ T cells in a dose- and APC-dependent manner.

Superantigens are potent activators of the immune system, causing a variety of diseases, ranging from food poisoning to septic shock. Here, we examined the effects of different toxic shock syndrome toxin 1 (TSST-1) concentrations on the activation, proliferation and synthesis of interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) in purified naïve human CD4+ T cells in a serum-free in vitro system. TSST-1 given in low doses (1-10 pg/ml) generates a pronounced T helper 2 (Th2)-like cytokine profile, characterized by elevated IL-4-expressing T-cell populations and reduced IFN-gamma-producing populations, whereas higher doses (100 pg/ml) induce a Th1-like profile, with increased expression of IFN-gamma and reduced expression of IL-4. These patterns were even more pronounced by adding exogenous cytokines like IL-12 and IL-4 and by the type of antigen-presenting cells (APCs). Thus, B cells induced Th2 shifts, whereas monocytes favoured Th1 induction. Moreover, IL-12 in conditions with B cells counteracted their Th2 bias. Interestingly, in purified naïve T-cell cultures, containing a small population of HLA-DR+ T cells, Th1/Th2 differentiation can be induced by TSST-1 too. There, Th-cell polarization is strongly dependent on TSST-1 concentration, indicating that this is a key parameter in regulating the differentiation of T cells. In conclusion, our data show that Th1/Th2 differentiation of TSST-1-stimulated naïve T cells is controlled by the type of APCs, and in APC-depleted cultures, it depends on the presence of HLA-DR+ cells and TSST-1 concentration.

Antigen Presentation↗
PubMed2000

Trichostatin A modulates expression of p21waf1/cip1, Bcl-xL, ID1, ID2, ID3, CRAB2, GATA-2, hsp86 and TFIID/TAFII31 mRNA in human lung adenocarcinoma cells.

Lung adenocarcinoma cells treated for 16 h with trichostatin A (TSA), an inhibitor of histone deacetylases, and untreated cells were analyzed with respect to differential gene expression. Complex hybridization of cDNA arrays revealed repression of Bcl-xL, CRAB2 and TFIID/TAFII31 as well as induction of p21waf1/cip1, GATA-2, hsp86, ID1, ID2 and ID3 mRNA expression, which could be verified by Northern blotting. ID2 induction was further confirmed by Taqman realtime quantitative RT-PCR. The described alterations of gene expression due to TSA renders the lung adenocarcinoma cells susceptible to induction of apoptosis.

Adenocarcinoma↗
PubMed2000

Trichostatin A-mediated regulation of gene expression and protein kinase activities: reprogramming tumor cells for ribotoxic stress-induced apoptosis.

Recently we described a new signal transduction-based tumor therapeutic strategy involving first sensitization of tumor cells by trichostatin A (TSA), an inhibitor of histone deacetylation, and thereafter efficient apoptotic triggering by ribotoxic agents, which activate stress-activated protein kinases. In the present work we investigate the molecular basis of the sensitization step in this therapeutic model system and describe TSA-induced changes in mRNA and protein expression of several candidate genes identified previously by complex hybridization. Furthermore, activities of 15 different protein kinases were followed after TSA application, using a new filter-based technique (PhosphoSpots-Assay). The obtained data suggest that TSA induces pro-apoptotic genes like ID1, ID2, ID3, and down-regulates anti-apoptotic genes like Hsp27 and Bcl-xL, thereby shifting the cellular equilibrium from life to death. Furthermore, activities of calcium/calmodulin-dependent kinase II and protein kinase C, which have been assigned pro-apoptotic function in other systems, are induced.

Apoptosis↗
PubMed1999

Normalization of array hybridization experiments in differential gene expression analysis.

For detecting and confirming differentially expressed genes it is necessary to have a trustworthy reference. So called 'housekeeping genes' are frequently used for this purpose as internal standard. However, if the influence of new experimental conditions is to be analyzed it is not safe to assume a priori that the expression of these genes is not affected. Therefore two synthetic poly(A)-RNAs were generated by PCR and in vitro transcription. They were used as external standards for normalization of northern blots and cDNA arrays where non-regulated genes as internal reference were not available.

Ampicillin Resistance↗
PubMed1999

Sensitization of tumor cells to ribotoxic stress-induced apoptotic cell death: a new therapeutic strategy.

We describe a procedure that sensitizes chemotherapy-and tumor necrosis factor-resistant human tumor cell populations in vitro and in nude mouse transplants to the immediate triggering of high rates of cell death by anisomycin, an agent causing activation of stress-activated protein kinases [SAPKs, as defined by P. Cohen (Trends Cell Biol., 7: 353-361, 1997)] including p38/RK and c-jun NH2-terminal kinase homologues, following its binding to ribosomal 28S RNA (M. S. Iordanov et al, Mol. Cell. Biol., 17: 3373-3381, 1997). Sensitization is effected by successive application of an inhibitor of histone deacetylation (trichostatin A, butyrate) and of flavopiridol, known as an inhibitor of cyclin dependent kinases and evaluated presently in clinical trials. Effective concentrations of anisomycin, flavopiridol, and trichostatin A are in the submicromolar range. Tumor cell death can be prevented by epidermal growth factor (EGF), if added before flavopiridol or after anisomycin but not if applied between the additions of these agents, suggesting that flavopiridol interrupts an EGF-activated survival pathway and that anisomycin, besides triggering cell death, guards this pathway against the interference by flavopiridol. In contrast to EGF, dibutyryl-cAMP exerts protection that is flavopiridol-insensitive. For triggering cell death, anisomycin cannot be replaced by DNA- or mitotic spindle-targeted drugs in this system. The present findings, that a combination of transcriptional and signal transduction-targeted modulators sensitizes tumor cells synergetically to stress-mediated triggering of cell death and that ribotoxic stress is more efficient in this respect than genotoxic or spindle-targeted stress, bear important implications for the therapeutic exploitation of cellular stress responses. The stepwise sensitization and triggering of cell death in the present system allow separate analysis and manipulation of processes contributing to cellular death susceptibility and of the mechanism responsible for triggering cell death, thus providing the operational basis for further development of this therapeutic approach.

Animals↗
PubMed1998

A new in vitro model for studying human T cell differentiation: T(H1)/T(H2) induction following activation by superantigens.

A new T(H1)/T(H2) in vitro model for mechanistic studies and drug screening in human T cells was established working with ficoll-separated PBMCs or elutriated lymphocytes cultured in serum-free medium. Human T cells could be kept viable and reactive in this medium for several months. In this model, superantigens (SAs) were used to activate exclusively those T cell clones which were known to express specifically SA-binding Vbeta-chains of the T cell receptor. It was possible to identify the activated SA-specific T cells among the whole T cell population by using monoclonal antibodies against these Vbeta-chains and to follow responses involving receptor regulation and cytokine expression. The flow cytometric analysis revealed, that SA exposure caused an upregulation of the IL-2 receptor selectively in the SA-specific subpopulation. Only the T cells of this subpopulation could be shifted towards T(H1) or T(H2) differentiation, which was determined by the distribution of IFN-gamma and IL-4 positive cells. Regulation of IFN-gamma could be detected by flow cytometry after 18 h and that of IL-4 on the third day of cell culture. The differentiation status could be influenced by various measures: T(H1) shifts were achieved in the presence of IL-12 and anti-IL-4, whereas, T(H2) shifts were induced more slowly with monocyte-reduced elutriated lymphocytes in the presence of IL-4, IL-6, anti-IL-12, 1alpha,25-dihydroxy-vitamin-D3 or combinations thereof. It was found that sialidase stimulated whereas TGF-beta and pentoxifylline suppressed both kinds of T cell response. The T(H1)/T(H2) differentiation persisted for several weeks after primary activation if cells were expanded in IL-2 containing serum-free culture medium. Therefore, this human T(H1)/T(H2) in vitro model should be ideal for studying early and late events of infection, allergy, and autoimmunity as well as for investigating the cellular interactions involved. In addition, the early detection of the response pattern makes this model potentially useful for drug screening.

Bacterial Toxins↗
PubMed1996

Induction of cell death by cytokines in cell cycle-synchronous tumor cell populations restricted to G1 and G2.

In the present work, cytokine-mediated induction of cell death was investigated by flow cytometry in cell cycle-synchronous human tumor cell populations gained by centrifugal elutriation or by cell cycle blockade with mimosine and aphidicolin. Attention was payed to the question of whether the effector phase of cell death takes place in the same phase of the cell cycle in which the death signal is received. Another point of interest was the question whether synchronization of cell populations with respect to the cell cycle leads to increased synchronicity of the death phase. The results demonstrate that supernatants from monocyte/tumor cell interaction cultures containing tumor necrosis factor-alpha, interferons, and interleukins-1 and -6 or appropriate combinations of pure cytokines cause cell cycle arrest predominantly in G1 and to a lesser extent in G2. Cell death is initiated from both arrest points. Cytokine-treated G1 cells do not enter S phase. They die within the same G1 phase in which they receive the death signal. In contrast, a high proportion of cytokine-treated G2 cells pass through mitosis and are arrested and die in the subsequent G1 phase, whereas only a smaller proportion of cells are arrested and die in G2. The synchronicity of the death phase cannot be increased by the diverse methods of cell cycle synchronization applied. Interestingly, aurintricarboxylic acid, an agent known for inhibitory effects on nucleolytic activities and other protein/nucleic acid interactions, not only prevents cell death, but also cell cycle arrest.

Aphidicolin↗
PubMed1993

Monocyte-mediated restoration of density-dependent growth control and induction of cell death in tumor cell populations.

It is shown in a serum-free system with human cells that during monocyte/tumor cell interactions signals are generated which restore the principles of density-dependent inhibition of growth in tumor cell populations. Tumor cells that fail to comply with these principles are induced to die. This cell death is an active process in target cells involving protein biosynthesis and tumor cell-derived signals.

Cell Death↗
PubMed1992

Cytokines involved in monocyte mediated tumor cell death and growth inhibition in serum-free medium.

In a serum-free culture system, the release of TNF, lI-1, lI-6, IFN-alpha, and IFN-beta during interaction of elutriated human monocytes (MO) with human tumor cells (TC) was studied by ELISA-technique. Contributions of these cytokines to inhibition of TC-growth and to induction of TC-death by supernatants (SU) gained from such MO/TC-interaction cultures were investigated using affinity chromatography for removal of individual cytokines. Although the TC used are relatively insensitive to recombinant human TNF, withdrawal of TNF causes 50% to 75% reduction of SU-induced TC-death rates, suggesting that susceptibility to TNF is raised during MO/TC-interaction by the other cytokines. Individual removal of other cytokines does not cause reduction of SU-mediated TC-death. However, combined withdrawal of lI-1 and IFN-alpha/beta causes in 2 of 4 TC-lines significant reduction of TC-death. Combined removal of TNF, IFN-alpha/beta, lI-1, and lI-6 leads to complete prevention of SU-mediated growth inhibitory and lytic effects, suggesting that besides these cytokines other signals are not involved significantly. SU-effects can be mimicked by appropriate combinations of authentic cytokines. The response of TC to SU- or cytokine-exposure is strikingly dependent on TC-density, leading at subconfluent TC-density exclusively to inhibition of growth and at postconfluent TC-density to induction of cell death. The principal effect of SU or cytokine combinations in this context seems to be the activation of growth inhibitory signal transduction pathways leading to TC-death in postconfluent TC-populations exclusively if growth stimulatory pathways are activated at the same time. Mouse L cells do not follow this reaction pattern: Their death is exclusively dependent on the presence of TNF in SU and they die upon SU-exposure at postconfluent as well as at subconfluent cell density.

Animals↗
PubMed1991

Suppression of tumor cell susceptibility to monocyte-induced cell death by growth-inhibitory signals generated during monocyte/tumor cell interaction.

In a recently established serum-free in vitro system it has been demonstrated that the susceptibility of various human tumor cells to the induction of cell death by elutriated human monocytes is critically dependent on tumor cell density and growth state. In the present work it is shown by flow cytofluorometric analysis of bromodeoxyuridine incorporation rates and of expression of the proliferation-associated nuclear antigen Ki-67, that tumor cells forced out of the cell cycle into the quiescent state (G0), which can be accomplished by treatment with supernatant from monocyte/tumor cell interaction cultures, are no longer susceptible to the induction of cell death by monocytes. This suggests that processes essential for the lytic pathway cannot take place in quiescent cells. It is furthermore demonstrated that tumor cells are driven into G0 during interaction with monocytes and that the rate of transit from G1 to G0 increases with increasing monocyte dosage. This explains our earlier finding that maximum rates of tumor cell death are induced at rather low monocyte:tumor cell ratios of around 1:2 and that lysis is suppressed at higher monocyte dosages (van der Bosch et al.:Exp Cell Res 187:185-192, 1990). The potential significance of these findings for the supposed function of mononuclear phagocytes in tumor defense lies in the notion that tumor cells driven into G0 might escape this control and that signals involved in monocyte/tumor cell-interaction contribute to the accumulation of tumor cells in G0.

Cell Communication↗
PubMed1991

Monocyte-mediated growth control and the induction of tumor cell death.

In the present article a hypothesis is put forward and supporting data are referred that explain the elimination of tumorigenic cells as a consequence of their failure to comply with the rules of ubiquitous negative growth control mechanisms involving among others also mononuclear phagocytes as effector cells. This hypothesis does not invoke the recognition of altered cell surface structures on tumorigenic cells as the basis for discriminating them from normal cells and thus avoids one of the most irritating problems of hypothetical tumor defense mechanisms involving the recognition of spontaneously arising tumor cells as 'non-self' by immunologic effector cells.

Animals↗
PubMed1990

Different phenotypes of cultured microvessel endothelial cells obtained from bovine corpus luteum. Study by light microscopy and by scanning electron microscopy (SEM).

Morphological heterogeneity has not been documented for cultured endothelial cells isolated from the microvascular bed of any organ. As the corpus luteum depends on a rich microvascularization, endothelial cells were dislodged from developing corpora lutea by mechanical dissection followed either by collagenase digestion or by no digestion. Cell separation was carried out by Percoll density centrifugation. Although the yield of intact cells was higher with collagenase treatment than without, successful endothelial cell cultures were only established when cells remained untreated. Viewed by light microscopy after an average lag phase of 10 days, five different phenotypes of endothelial cells were found under similar simple culture conditions: isomorphic epithelioid, polymorphic epithelioid, spindle-shaped, round, and phase-dense phenotypes. Monolayers appeared within 2-4 weeks. After an additional period of 2-4 weeks, tubular forms with a specific pattern were noted for types 1-3, the so-called pseudotubular forms for type 4, and none for type 5. Cell types differed in their cytochemical and immunocytochemical responses. Examined by SEM, type 1 displayed a more conspicuous surface anatomy than type 2. Types 3-5 demonstrated striking cell processes that were characteristic of each type. Tubular forms of types 1 and 2 showed cell borders and a marked increase in surface specializations, whereas tubular forms of type 3 lacked detectable cell borders in the absence of a striking surface anatomy. Pseudotubular forms of type 4 developed no particular spatial organization. Thus, for the first time, morphological evidence is provided that different endothelial cell types are obtained from diverse segments of the microvascular bed.

Acid Phosphatase↗
PubMed1990

Density-dependent tumor cell death and reversible cell cycle arrest: mutually exclusive modes of monocyte-mediated growth control.

The population development of five human tumor cell lines is examined under the influence of elutriator-prepared human monocytes in a serum-free hormone- and growth factor-supplemented medium. Analysis was performed by electronic counting and sizing of tumor cell nuclei and flow cytometric detection of cell cycle phases. Tumor cell death is triggered at rather low monocyte:tumor cell ratios (1:2 to 1:4) whereas it is strongly reduced at high monocyte densities. Furthermore, it is shown that confluence of the target cell population is a necessary prerequisite for lysis. The data suggest that in monocyte/tumor cell cocultures the decision on target cell lysis is not made by the effector cell, but rather by the target cell and that the criterion for this decision is the target cell's ability or inability to respond to a monocyte challenge by arresting the cell cycle in G1. Interactions between target cells play an important role in determining the result of this decision process. A common basis is suggested for this kind of density-dependent monocyte-triggered lysis and density-dependent cell death in 3T3 cell cultures as described previously.

Cell Cycle↗
PubMed1989

Monocyte long-term cultivation on microvascular endothelial cell monolayers: morphologic and phenotypic characterization and comparison with monocytes cultured on tissue culture plastic.

Human monocytes were cultured on monolayers of a newly established microvascular endothelial cell strain. As compared to monocytes cultured on plastic, these endothelium-"derived" monocytes (EDM) showed distinct morphology, higher motility, and different antigen-expression pattern for several surface markers, as detected by cytofluorimetry. The MO-1- and the Leu-M1-marker were maintained on EDMs while they were lost on plastic-cultured cells. The MAX 1-26-termed markers failed to increase on EDMs, in contrast to plastic-cultured monocytes. For seven additional markers, expression after two weeks in vitro was higher on EDMs than on plastic-cultured monocytes. Functionally EDMs showed typical monocyte/macrophage behavior and were easily removable from the culture system for further experimentation. Our data suggest that monocytes cultured on microvascular endothelial cells are maintained for several weeks in a more physiologic state than monocytes cultured on plastic.

Animals↗
PubMed1987

Activity of cancer chemotherapeutic agents against human colorectal carcinomas grown as primary tissue culture.

Improved procedures are described for the seeding of primary cultures from human colon adenocarcinoma and for the use of these cultures in the evaluation of drug effects. Two of the specimens studied were xenografts maintained in athymic (nude) mice, while the other six were biopsies obtained directly from patients. Tumor cells obtained directly from the patients proliferated in defined hormone-supplemented medium to the exclusion of other cells. In drug-response studies with cultures from a colon tumor biopsy all four drugs studied (4'-deoxydoxorubicin, 4'-O-methyldoxorubicin, 5-fluorouracil, and 1,3-bis-[chloroethyl]-1-nitrosourea) inhibited growth of the cells within 3-6 days after drug treatment. On an equitoxic dose basis (LD10 in mice), 4'-deoxydoxorubicin appeared to be the most active drug. This drug also showed dose-dependent activity against one of the xenografted tumors in vitro. In dose-response studies with cultures from another patient's colon tumor, doxorubicin and 5-fluorouracil showed significant activity against the tumor 10 days after the drug treatment with concentrations at 1X and 10X average peak plasma levels.

Animals↗
PubMed1984

The chick oviduct in tissue culture. I. Initial characterization of growing primary oviduct tissue cultures.

A simple three-enzyme treatment of collagenase, dispase and hyaluronidase on finely minced chick oviduct yields clumps of 50-150 cells. These cells attach to collagen-treated dishes and survive in culture for at least 2 weeks without subculturing. Oviduct cell cultures can also be induced to grow. Estradiol or epidermal growth factor (EGF) induce a 40% increase in cells in 4 days when cultures are grown in serum levels that do not support growth. Serum from estrogen-stimulated chicks promotes rapid cellular proliferation (doubling times of 1-2 days). Sera from estrogen withdrawn chicks, laying hen or horse do not support as rapid proliferation. The oviduct growth-promoting factors in serum from estrogen-stimulated chicks are not steroids or fibroblast growth factors (FGF). Removal of steroids from these sera by charcoal treatment or delipidization does not decrease the rate of growth. The addition of 1-100 nM estradiol does not increase a serum's ability to promote growth. Purified FGF or platelet-derived growth factor (PDGF) do not induce oviduct proliferation. These results were reproduced in oviduct cell cultures started from estrogen-stimulated and withdrawn chicks as well as laying hens. Thus the factors in serum from estrogen-stimulated chicks that promote rapid oviduct growth are induced by estrogen treatments in vivo, but do not seem to be only steroids.

Animals↗
PubMed1982

Growth state-specific responsiveness of primary cultures of a nude mouse-xenografted human colon carcinoma to 4'-deoxydoxorubicin and a crude human leukocyte alpha-interferon preparation.

Improved procedures for the seeding of primary cultures from human colon tumors are described. Responsiveness of primary cultures from human colon carcinoma T348 to a crude preparation of human leukocyte alpha-interferon and a DNA-intercalating experimental anticancer drug, 4'-deoxydoxorubicin, has been investigated. The effect of the interferon preparation on such cultures is shown to be growth state specific; i.e., stationary populations are killed, whereas fast-growing cultures are reversibly growth inhibited by the same doses of interferon. In contrast, 4'-deoxydoxorubicin kills growing populations, whereas stationary cultures are barely affected by the same concentration of this drug. Interferon antagonizes the cytotoxic effect of 4'-deoxydoxorubicin on a growing colon tumor cell population when applied immediately after 4'-deoxydoxorubicin treatment. Implications of this finding for the combined application of several drugs in cancer therapy are discussed.

Animals↗