Biomedical subjects

H G Derigs

Publications and source records attributed to H G Derigs.

24 records · Page 2Linked to original sources

PubMed1994

Granulocyte-macrophage colony-stimulating factor expression is regulated at transcriptional and posttranscriptional levels in a murine bone marrow stromal cell line.

We have reported modulation, by cytokines interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) and by hormonal cyclic-adenosine-monophosphate (cAMP) agonists, of hematopoietic growth factor production in the murine marrow adherent cell line +/+(-)1.LDA11. Previously, we reported that increased intracellular cAMP levels inhibited bioactive granulocyte-macrophage colony-stimulatory factor (GM-CSF) production stimulated by IL-1 or by the synergistic stimulus of IL-1 plus TNF-alpha. On the other hand, increased intracellular cAMP stimulated IL-6 synthesis in +/+(-)1.LDA11 cells. In addition, cAMP was additive with either IL-1 or IL-1 plus TNF-alpha in inducing production of soluble IL-6. In the present study, these observations were pursued mechanistically at the level of messenger RNA (mRNA) production. Northern blot analysis of steady-state mRNA for GM-CSF revealed induction by treatment of +/+(-)1.LDA11 cells with IL-1 or with TNF-alpha. The combined stimulation by IL-1 plus TNF-alpha resulted in supra-additive increases in GM-CSF expression by +/+(-)1.LDA11. Addition to stromal cells of the soluble cAMP agonist 8-bromo-cAMP (8BrcAMP) at 0.5 to 1 mM stimulated IL-6 mRNA expression acting alone, and it was additive with IL-1 or IL-1 plus TNF-alpha in stimulating IL-6 expression. On the other hand, 8BrcAMP inhibited GM-CSF mRNA expression stimulated by IL-1 or IL-1 plus TNF-alpha. Inhibition of GM-CSF mRNA by 8BrcAMP was time-dependent, starting 120 to 180 minutes posttreatment. In addition, inhibition of GM-CSF transcript expression in +/+(-)1.LDA11 by 8BrcAMP required the expression of a labile protein. Nuclear run-on assays revealed that GM-CSF and IL-6 genes were transcriptionally induced in +/+(-)1.LDA11 by incubation with IL-1 plus TNF-alpha. IL-6 transcription was further enhanced by 8BrcAMP co-incubation. More sensitive experiments using a luciferase reporter vector containing the GM-CSF promoter region were necessary to convincingly establish the role of TNF-alpha and 8BrcAMP on transcriptional induction of the GM-CSF gene in +/+(-)1.LDA11 stromal cells. Considering these results and an effect of 8BrcAMP on decreasing GM-CSF transcript stability in actinomycin-D (act-D) decay experiments, we conclude that the inhibitory effect of 8BrcAMP on GM-CSF expression is exerted at the posttranscriptional level. These data demonstrate that the intracellular level of cAMP has an important discriminatory role on expression of the cytokines GM-CSF and IL-6 in a model stromal cell line.

Animals↗

PubMed1993

LIF mRNA expression is transcriptionally regulated in murine bone marrow stromal cells.

Recent evidence has established an important role for leukemia inhibitory factor (LIF) as hematopoietically active cytokine. The present study utilized two different murine bone marrow stromal cell lines, +/+-1.LDA11 and MBA-13, to define regulatory mechanisms of LIF messenger RNA (mRNA) induction. LIF mRNA was not detected in uninduced stromal cells under serum-free conditions. Incubation with interleukin-1 (IL-1), tumor necrosis factor-alpha (TNF-alpha) or the cAMP analogue 8-bromoadenosine 3':5'-monophosphate (8BrcAMP) resulted in weakly induced LIF mRNA. Coincubation of combinations of the stimuli increased LIF mRNA expression additively. LIF mRNA stability, even after stimulation, was low with a half-life of about 30 min, suggesting a functional role for known AU-rich motifs in the 3' untranslated LIF mRNA region in mediating this instability. This possibility was further supported by the ability of cycloheximide to increase mRNA levels without affecting transcription. Transcriptional activation was found to be the main mechanism leading to LIF mRNA expression by IL-1, by TNF-alpha, and by 8BrcAMP. These stimuli appeared to act additively in this regard, suggesting involvement of distinct transcription factors. Induction of transcription was detected 45 min post-stimulation and showed peak levels at 90 min. Kinetics of LIF transcriptional activation showed similarity with the kinetics of the transcription factors, jun-B and c-fos, suggesting a possible role for these proteins or other early response genes in events leading to LIF expression.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1990

Role for cyclic AMP in the postreceptor control of cytokine-stimulated stromal cell growth factor production.

We examined the role of augmented formation of intracellular cyclic AMP (cAMP) in the mediation of stromal cell growth factor production that occurs constitutively or upon cytokine stimulation. Clonal murine marrow adherent cell lines were stimulated under serum-free conditions by interleukin-1 (IL-1) or lipopolysaccharide (LPS) and one (+/+ -1.LDA11) was found to produce low quantities of granulocyte macrophage colony-stimulating factor (GM-CSF). GM-CSF identity was confirmed by the ability of supernatants from stromal cells to promote proliferation of the factor-dependent cell line FDC-P1, neutralization of this activity by antiserum to GM-CSF, and by Northern blot analysis. However, optimal concentrations of IL-1 and tumor necrosis factor-alpha (TNF-alpha), in combination, led to synergistic (greater than 5-fold higher quantity) GM-CSF production compared with either stimulus alone in the +/+ -1. LDA11 cell line, capable of GM-CSF production after only single stimulation with IL-1 or LPS. In addition, synergistic stimulation by IL-1 and TNF-alpha led to equivalent high amounts of GM-CSF in another cell line incapable of GM-CSF production after induction with only IL-1 or LPS. Any of several means to raise intracellular cAMP levels, including addition of 8-bromo-cyclic AMP (8Br cAMP) (0.25-1mM), pertussis toxin (20-100 ng/ml), or addition of prostaglandin E1 (PGE1) (1 microM), failed to stimulate GM-CSF production alone and strongly inhibited GM-CSF production in stromal cells stimulated by IL-1, LPS, or the synergistic combination of IL-1 and TNF-alpha. In addition, PGE1 and pertussis intoxication were agonists of adenylate cyclase in membranes of marrow adherent cells, whereas IL-1 and LPS were not. The role for regulators of intracellular cAMP was specific because any of the cAMP agonists alone, or in the presence of cytokine stimulators of stromal cells, strongly enhanced IL-6 production, an event known to be cAMP-responsive. Thus, acute formation of intracellular cAMP is a negative regulator of stromal cell GM-CSF production mediated by cytokines, but positively regulates IL-6 production and may be an important determinant of cytokine-directed marrow microenvironmental function. These findings on the requirement for augmentation versus inhibition of cytokine-mediated production of hemopoietic growth factors might be applied to an analysis of marrow stromal cell heterogeneity.

Adenylate Cyclase Toxin↗

PubMed1989

Effector function for RAS oncogene in interleukin-3-dependent myeloid cells involves diminished efficacy of prostaglandin E1-mediated inhibition of proliferation.

Leukemic cell growth in the marrow microenvironment may be modulated by stromal cell products, including stimulatory growth factors and the inhibitory regulator prostaglandin E. The production of both of these stromal cell products induced by cytokine mediators appears to be closely linked. Cyclic AMP (cAMP) is an intracellular second messenger that inhibits myeloid cell proliferation and is produced in myeloid leukemia cells on stimulation of adenylate cyclase enzyme by prostaglandin E1 (PGE1). Cells expressing the product of an RAS oncogene have been observed to display diminished hormone-stimulated adenylate cyclase of membranes. If this observation were applicable to myeloid cells, a potentially important mode for leukemia cells expressing p21 RAS to escape inhibitory regulation within the hematopoietic microenvironment would be identified. We studied an interleukin-3 (IL-3)-dependent myeloid cell line, NFS/N1.H7, and a derivative line transfected with H-RAS codon 12 (T24) oncogene, H7 Neo Ras.F3, for inhibition of proliferation by PGE1, 1 microM, alone or in combination with pertussis toxin, which inactivates Gi, an inhibitory regulatory guanosine triphosphate (GTP)-binding protein of adenylate cyclase. NFS/N1.H7 cells were inhibited in interleukin-3-dependent proliferation (dose range, IL-3 10 to 100 U/mL) by PGE1 79 +/- 11%, by pertussis toxin 51 +/- 9%, and by the combination 92 +/- 2%, whereas H7 Neo RAS.F3 was inhibited 51 +/- 7%, 6 +/- 2%, or 58 +/- 9% by PGE1, pertussis toxin, and the combination, respectively. These differences in capacity for inhibition by adenylate cyclase agonists between RAS-transfectant cells (lower inhibition) versus parent cells (greater inhibition) were all highly significant (P less than .0005). Intracellular cAMP formed on PGE1 stimulation of pertussis-intoxicated cells was 150% lower in RAS-transfectant cells than in parent cells. The adenylate cyclase activity of membranes from pertussis-intoxicated RAS-transfected cells was 1.5 to two times lower than that of pertussis-intoxicated parent-cell membranes on Mg2+-dependent activation by hormone and/or guanine nucleotide. However, very similar adenylate cyclase activity was observed in oncogenic p21 RAS-containing membranes compared with parental membranes under conditions of direct activation by 4 mM Mn2+ and forskolin, where inhibitory or stimulatory G-protein influences are minimal. These studies showed diminished adenylate cyclase activity in mutant RAS-bearing myeloid-cell membranes compared with parent-cell membranes independent of the pertussis toxin-sensitive G protein, Gi.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenosine Diphosphate Ribose↗

PubMed1989

A mutant RAS gene acts through protein kinase C to augment interleukin-3 dependent proliferation in a fastidious immortal myeloid cell line.

The functional role of a mutant RAS gene in immortal myeloid cell proliferation was examined in a fastidious interleukin-3 (IL-3) dependent cell line (NFS/N1.H7) formed by forced proliferation in IL-3 of marrow cells of the NFS/N mouse. The NFS/N1.H7 cell line was strictly dependent upon IL-3 for growth, and the cell line could be activated by phorbol esters (PMA) to augment IL-3 dependent proliferation, but when pKC was downregulated, diminished IL-3 proliferative response resulted. Transfection (electroporation) of the T24 RAS-containing vector pAL8 to NFS/N1.H7 led to clones (H7 NeoRas.F3, H7 NeoRas.E2) that had incorporated the entire 6.6 Kb human mutant H-RAS genome. The mutant RAS-containing clones demonstrated greater proliferation than parent cells or cells containing a control (neo-resistance) vector over a range of suboptimal IL-3 does and in optimal IL-3 concentrations had a faster doubling rate than parent cells. The clone H7 NeoRas.F3 was studied biochemically, and found to constitutively form 3-fold more 3H-diacylglycerol than the parent cell line upon exposure to 3H-glycerol. PMA could partially repair the proliferative defect of NFS/N1.H7 compared to the RAS-expressor. These studies affirm a secondary, accelerating role for a mutant RAS gene product acting through pKC to promote clonal expansion of immortal myeloid cells stimulated by IL-3.

Animals↗

PubMedDate not supplied

Topical transforming growth factor-beta3 in the prevention or alleviation of chemotherapy-induced oral mucositis in patients with lymphomas or solid tumors.

Transforming growth factor (TGF)-beta3 has been hypothesized to prevent or alleviate oral mucositis (OM) in cancer patients receiving high-dose chemotherapy (CT). Two double-blind, placebo-controlled, multicenter, phase II studies of TGF-beta3 were initiated in the United States, Europe, and Argentina in patients with lymphomas or solid tumors who were receiving highly stomatotoxic CT regimens. Patients were to apply 10-mL mouthwash applications of TGF-beta3 (25 microg/mL) or placebo four times daily (or twice daily) 1 day before and all days during CT. The patients were subsequently evaluated for OM incidence, severity, and duration using National Institute of Cancer Common Toxicity Criteria (NCI-CTC) criteria and an objective scoring system (1). After the start of the trials, negative results from new preclinical studies suggesting suboptimal formulation and/or dosing led to an interim analysis of the ongoing clinical trials. One hundred fifty-two patients from the combined studies were included in the interim analysis, with 116 patients on the TGF-beta3 four times daily and placebo arms. Most (72%) patients had breast cancer, 22% had lymphomas, and 6% had other solid tumors. Although 98% (149 of 152) of patients experienced adverse events, only 14% (22 of 152) experienced events that were judged as possibly or probably related to the study drug (primarily gastrointestinal symptoms). No clinically relevant differences were seen between the treatment and placebo arms regarding safety, nor was there evidence for systemic absorption of TGF-beta3. Finally, there was no advantage of TGF-beta3 treatment regarding the incidence (TGF-beta3 four times daily versus placebo [46% versus 47%]), onset, or duration of NCI-CTC grade 3 or 4 OM. For this dose, formulation, regimen. and patient population, TGF-beta3 was not effective in the prevention or alleviation of CT-induced OM.

Adult↗