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S D Nimer

Publications and source records attributed to S D Nimer.

At least 55 records · Page 3Linked to original sources
PubMed1996

Adjacent, cooperative elements form a strong, constitutive enhancer in the human granulocyte-macrophage colony-stimulating factor gene.

Both copies of a repeated sequence CATT(A/T), located between bp -53 and -39 in the upstream region of the human GM-CSF gene, are required for mitogen-inducible promoter activity in T lymphocytes. However, the proteins that recognize this region of the granulocyte-macrophage colony-stimulating factor (GM-CSF) promoter, and are responsible for its transcriptional regulatory activity, have not been clearly identified. Using transient transfection assays, we demonstrate that a 19-bp oligonucleotide containing the CATT(A/T) repeats has strong constitutive enhancer activity in both T cell and non-T-cell lines, even though GM-CSF is not normally constitutively expressed by these cells. A 12-bp oligonucleotide, containing only the sequence CATTAATCATTT, lacks enhancer activity indicating that the nucleotides surrounding these sequences are critical for this enhancer activity. The sequence TTTCCT, which can bind members of the ets family of transcription factors, is located just 3' of these CATT(A/T) repeats, and mutagenesis of the CCT sequence abolishes (1) the constitutive (and mitogen inducible) enhancer activity of the 19-bp GM-CSF sequences, (2) the responsiveness to transactivation by ets-1, and (3) the ability to specifically bind ets-1 and elf-1 in electrophoretic mobility shift assays (EMSA). We demonstrate that although T cells contain nuclear proteins capable of independently recognizing the ets binding site and the CATT(A/T) repeats in EMSAs, both of these regulatory elements are required for enhancer function. The strong constitutive activity of this 19-bp region suggests that negative regulation of the GM-CSF promoter is critical for the restricted expression pattern of GM-CSF mRNA.

Base Sequence↗
PubMed1996

Infectious complications of autologous bone marrow and peripheral stem cell transplantation for refractory leukemia and lymphoma.

We aimed to characterize the infectious complications of autologous bone marrow (AuBMT) and peripheral stem cell transplantation (PSCT) in patients with refractory leukemia and lymphoma. We performed a retrospective analysis of all patients (n = 56) with refractory leukemia or lymphoma treated with AuBMT or PSCT at Memorial Sloan-Kettering Cancer Center from January 1993 to July 1994. Records were available in 55, of whom 33 (60%) received AuBMT and 22 (40%) PSCT. Fifteen (27%) developed complicated infections, including 13 (39%) treated with AuBMT and two (9%) with PSCT. Complicated infections were caused by bacterial (11 episodes), fungal (four episodes), and viral (four episodes) pathogens. Five (9%) infections were fatal. In a multivariate model, only duration of neutropenia was significantly associated with development of complicated infection (P = 0.006). Thus, 27% of patients with refractory leukemia or lymphoma treated with AuBMT or PSCT developed complicated infections and 9% died of infection. Prolonged neutropenia was significantly associated with development of infection. Patients receiving PSCT had significantly lower rates of complicated infection, presumably due to the associated shorter duration of neutropenia. Future studies are needed to define the role of PSCT as treatment for refractory neoplastic disease.

Adult↗
PubMed1995

The AML1/ETO fusion protein blocks transactivation of the GM-CSF promoter by AML1B.

The t(8;21) translocation, commonly found in acute myelogenous leukemia (AML), generates a fusion protein containing N-terminal AML1 and C-terminal ETO amino acids. The human AML1 gene encodes several related proteins that specifically bind to the sequence TGT/cGGT, located in the promoter regions of a variety of hematopoietic growth factor genes. To examine the abilities of the AML1B protein (which contains 479 amino acids), a shorter AML1A isoform (which contains amino acids 1-250), and the AML1/ETO fusion protein (which contains AML1A amino acids 1-177) to stimulate transcription from the GM-CSF promoter, we performed co-transfection experiments in T cells using a human GM-CSF promoter-CAT reporter gene plasmid and expression vectors that contain the cDNAs for one of the above proteins. Our data demonstrate that AML1B, but not AML1A or AML1/ETO transactivates the GM-CSF promoter, requiring the TGTGGT sequence contained between base pairs -68 and -53. Furthermore, we show that AML1/ETO, but not AML1A, inhibits the ability of AML1B to stimulate CAT expression. Electrophoretic mobility shift assays demonstrated the specific binding of AML1 proteins to the GM-CSF promoter TGTGGT sequence, which does not require GM-CSF sequences immediately upstream of this binding site. Our data support a role for AML1B as a transcriptional activator and establish that the AML1/ETO fusion protein can act as a dominant negative protein on the human GM-CSF promoter. Although AML1/ETO does not stimulate the transcription of GM-CSF, it may function by inhibiting the normal activity of AML1B in AML cells with the t(8;21) translocation.

Base Sequence↗
PubMed1995

A phase I trial of recombinant human interleukin-6 in patients with myelodysplastic syndromes and thrombocytopenia.

To evaluate the hematologic effects of recombinant human interleukin-6 (rhIL-6, Escherichia coli, SDZ ILS 969, IL-6), and determine its toxicity profile, we performed a phase I trial of IL-6 in 22 patients with various myelodysplastic syndromes (MDS), platelet counts < 100,000/microL, and < 5% bone marrow (BM) blasts. Patients received one of four doses of IL-6 (1.0, 2.5, 3.75, and 5.0 micrograms/kg/d) as a subcutaneous injection on day 1, followed by a 7-day wash-out period, and then 28 days of IL-6 therapy. Dose-limiting toxicities of fatigue, fever, and elevated alkaline phosphatase were seen at 5.0 micrograms/kg/d; the maximum tolerated dose was 3.75 micrograms/kg/d. All patients experienced at least grade II fever and all had an increase in acute phase proteins. Eight patients (36%) experienced at least a transient improvement in platelet counts; three fulfilled the criteria for response, whereas five others had clinically significant increases that failed to meet response criteria. Various IL-6-related toxicities prevented more than three patients from receiving maintenance therapy. Two of the three patients who received maintenance IL-6 therapy had a persistent increase in platelet counts, during 3 and 12 months of IL-6 therapy, respectively. Laboratory studies indicated that IL-6 increased the frequency of higher ploidy megakaryocytes but did not significantly increase the number of assayable megakaryocytic progenitor cells, suggesting that IL-6 acts as a maturational agent rather than a megakaryocyte colony-stimulating factor. Although IL-6 therapy can promote thrombopoiesis in some MDS patients, its limited activity and significant therapy-related toxicity preclude its use as a single agent in this patient population. Further studies, combining low doses of IL-6 with other hematopoietic growth factors, are underway.

Acute-Phase Proteins↗
PubMed1995

Long-term outcome of aplastic anemia in adults treated with antithymocyte globulin: comparison with bone marrow transplantation.

The outcome of 155 adult aplastic anemia (AA) patients treated with antithymocyte globulin (ATG, Upjohn, Kalamazoo, MI) at University of California, Los Angeles from 1977 to 1988 was evaluated. The median survival of the 146 patients who did not undergo bone marrow transplantation was 5.6 years, with 49% +/- 4% surviving more than 6 years. The most important predictor of survival was positive response to ATG (P < 0.001), which was observed in 48% of patients. Among pretreatment variables, disease severity was the best predictor of survival. Patients with moderate AA (MAA) had significantly better survival than those with severe (SAA) or very severe (VSAA) disease (P = 0.04). The 6-year actuarial survival rates of the three groups were 71% +/- 9%, 48% +/- 7% and 38% +/- 7%, respectively. Cox regression analysis found disease severity to be the only pretreatment variable significantly associated with survival (P = .02). Patient age, sex, disease etiology, concurrent treatment with androgens, or duration of ATG therapy were not associated with differences in survival or response to ATG. Late clonal hematologic complications (ie, myelodysplasia, acute myelogenous leukemia) were observed in 5 of the 77 patients followed for more than 2 years after ATG treatment. In addition, one case of non-Hodgkin's lymphoma and three solid tumors occurred in the ATG-treated patients. The survival of 56 ATG-treated patients with SAA or VSAA between the ages of 16 and 43 did not differ significantly from that of 55 adult AA patients who underwent bone marrow transplant (BMT) during the same time period (P = 0.6). However, 6-year survival rates improved from 43% for patients transplanted before 1984, to 72% for those who underwent BMT between 1984 and 1989. In contrast, there was no difference in the survival rates of patients treated with ATG during these two time periods (46% v 45%, respectively). The results suggest a superior long-term outcome for adult patients with SAA treated with BMT rather than with ATG alone, using current protocols.

Adolescent↗
PubMed1995

Regulation of granulocyte-macrophage colony-stimulating factor and interleukin 3 expression.

Granulocyte-macrophage colony stimulating factor (GM-CSF) and interleukin 3 (IL-3) are multilineage acting hematopoietic growth factors which have overlapping but distinct biological properties. Cellular sources of IL-3 are confined to activated T cells, natural killer (NK) cells, mast cells and possibly megakaryocytes, while these cells and activated macrophages, fibroblasts and endothelial cells are important sources of GM-CSF. In vitro studies have implicated both cytokines in the autocrine growth of human myeloid or murine mast cell leukemias. The human GM-CSF and IL-3 genes map to the long arm of chromosome 5, show similar genomic structures, and share several conserved elements in their 5' and 3' flanking regions. The promoters of these genes contain a variety of positive and negative regulatory regions, and the level of expression of these genes is controlled by both transcriptional and post-transcriptional mechanisms.

Base Sequence↗
PubMed1995

An interferon-gamma activation sequence mediates the transcriptional regulation of the IgG Fc receptor type IC gene by interferon-gamma.

Expression of the IgG Fc receptor type I (Fc gamma RI) on myeloid cells is dramatically increased by treatment with interferon-gamma (IFN-gamma). We observed that Fc gamma RI transcript levels in monoblast-like U937 cells were elevated within 3 hr and peaked 12 hr after exposure to IFN-gamma. Treatment of U937 with IFN-gamma for 9 hr in the presence of cycloheximide led to super-induction of Fc gamma RI expression. Nuclear run-on analysis revealed that the rate of Fc gamma RI transcription was increased by IFN-gamma. Genomic sequence upstream of the Fc gamma RIC gene was cloned and subjected to primer extension analysis, which demonstrated a single transcription initiation site without a TATA box. Transient transfections of CAT reporter gene constructs containing various Fc gamma RIC promoter sequences into U937 cells revealed that a 20-bp region surrounding the transcription start site (-7 to +13) was capable of mediating transcription initiation and that an IFN-gamma responsive element (GIRE) was present within 74 bp upstream of the transcription initiation site. A 17-bp sequence between positions -51 and -35 conferred IFN-gamma responsiveness on a heterologous promoter. Double-stranded GIRE sequence, but not a scrambled sequence, was specifically bound by nuclear proteins from IFN-gamma treated U937 cells. Gel shift experiments further showed that the STAT1 alpha protein bound to the Fc gamma RIC GIRE in response to IFN-gamma treatment of U937 cells. The Fc gamma RIC GIRE is homologous to the IFN-gamma activation sequence (GAS) of the guanylate binding protein and to X box elements of class II MHC genes. Our results demonstrate that transcriptional regulation of the Fc gamma RIC gene by IFN-gamma involves the binding of STAT1 alpha to a 17-bp GAS homology in the proximal promoter.

Animals↗
PubMed1995

Molecular cloning and characterization of NF-IL3A, a transcriptional activator of the human interleukin-3 promoter.

To isolate transcription factors important in the regulation of the human interleukin-3 (IL-3) gene, we screened a lambda gt11 cDNA library, constructed from phytohemagglutinin-stimulated human T-cell RNA, with a probe containing regulatory sequences in the upstream region of the IL-3 gene (located from bp -165 to -128 and referred to as the DNase I footprint A region). We isolated a 0.96-kb cDNA that encoded a basic amino acid domain and a leucine zipper domain and used the "rapid amplification and cloning of 3' ends" technique to isolate the 3' half of the cDNA clone, generating a 1.9-kb full-length cDNA clone. Using in vitro-translated protein, which we call NF-IL3A, we defined the IL-3 promoter sequences bound by NF-IL3A in DNase I footprinting assays as TAATTACGTCTG and, using gel shift assays, defined ATTACG as the minimal sequence required for binding of NF-IL3A in vitro. Proteins that bind to the NF-IL3A binding site are found in both unstimulated and stimulated T-cell lines in similar amounts, although the level of NF-IL3A mRNA increases after T-cell activation in several mature T-cell lines. The NF-IL3A protein is nearly identical to a recently identified transcriptional repressor protein, E4BP4, and NF-IL3A binds specifically to regulatory sequences in both the adenovirus E4 promoter and the human gamma interferon promoter. Cotransfection experiments demonstrate that introduction of an expression vector containing the NF-IL3A cDNA into resting T cells transactivates IL-3 promoter-chloramphenicol acetyltransferase gene plasmids that contain the A region; this effect requires the presence of an intact NF-IL3A binding site. One or more copies of the A region also confer NF-IL3A responsiveness on a heterologous promoter in T cells. NF-IL3A appears to play an important role in the expression of IL-3 by T cells.

Amino Acid Sequence↗
PubMed1995

Isolation of the human peroxisome proliferator activated receptor gamma cDNA: expression in hematopoietic cells and chromosomal mapping.

The nuclear receptor superfamily of transcription factors, which includes the retinoic acid receptors and v-erb A, play important roles in the molecular control of hematopoiesis. To identify nuclear receptors expressed in hematopoietic cells, we screened a human bone marrow cDNA library using a degenerate oligonucleotide and isolated a 1.85-kb full-length cDNA encoding a new human member of this superfamily, the peroxisome proliferator activated receptor gamma (hPPAR gamma). Two different hPPAR gamma transcripts were expressed in hematopoietic cells: a 1.85-kb transcript, which corresponds to the full-length mRNA (PPAR gamma 1), and a 0.65-kb transcript (PPAR gamma 2), which cannot encode all of the nuclear receptor functional domains. Normal neutrophils and peripheral blood lymphocytes, as well as circulating leukemic cells from patients with AML, ALL, and CML, express only PPAR gamma 2 on Northern blot analysis. In contrast, only the PPAR gamma 1 transcript was detected in a variety of human leukemia cell lines and in cultured normal primary bone marrow stromal cells. Both transcripts were detected in various fetal and adult nonhematopoietic tissues. We mapped the location of the hPPAR gamma gene to human chromosome 3p25 by somatic cell hybridization and linkage analysis. PPARs have been shown to be activated by peroxisome proliferating agents, long-chain fatty acids and arachidonic acid. Human PPAR gamma, although homologous to the PPAR gamma s of other species, has unique sequence and amino acid differences. Identification of hPPAR gamma will allow further understanding of its role in human cellular leukotriene, prostaglandin, and peroxide degradative or synthetic pathways, as well as its role in lipid metabolism and regulation of adipocyte differentiation.

Adult↗
PubMed1994

Characterization of nuclear factors that bind to a critical positive regulatory element of the human granulocyte-macrophage colony-stimulating factor promoter.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a hematopoietic growth factor that stimulates the proliferation, maturation, and functional activity of myeloid cells in peripheral blood and bone marrow. Expression of GM-CSF is tightly regulated and is limited to cells stimulated directly (T cells, macrophages) or indirectly (fibroblasts, endothelial cells) by immune challenge. Several studies of the transcriptional control of GM-CSF expression have elucidated a region of the GM-CSF promoter that mediates positive regulatory activity in a number of cell types. This region contains a direct repeat of the sequence CATTA/T that extends from nucleotides -37 to -48 upstream of the start of mRNA synthesis. Although specific DNA:protein interactions have been shown within this region, neither the nature nor the number of nuclear factors responsible for these interactions have been characterized. In this study, we use DNase I footprinting analysis to demonstrate that point mutations, which inactivate the GM-CSF promoter, disrupt DNA:protein interactions within this region. By combined electrophoretic mobility shift and ultraviolet cross-linking analysis, we have detected several protein species that bind specifically to the positive regulatory sequence.

Base Sequence↗
PubMed1994

An increased HLA DR2 frequency is seen in aplastic anemia patients.

The underlying etiology of aplastic anemia is unknown in the majority of patients, although medications, chemical exposure, or viral infections can be implicated in some. Genetic susceptibility to a variety of diseases has been shown and it has recently been suggested that aplastic anemia is more common in individuals who are HLA DR2+ than in the general population. To examine this question, we retrospectively analyzed the results of HLA-DR typing in 75 aplastic anemia patients who received antithymocyte globulin (ATG) therapy or an HLA-matched sibling bone marrow transplant at UCLA between 1978 and 1989. Thirty-one patients were DR2+, a 1.9-fold higher incidence than the expected number of 16.6 patients (P < .0005). Of the 37 patients who received ATG, 33 were evaluable for a response; 14 patients had either a complete (4 patients) or partial (10 patients) response, for an overall response rate of 42.4%. Of the 14 DR2+ patients who received ATG, 7 responded, for a 50% response rate, which is not significantly higher than the response rate for the DR2- patients (7 of 19 [36.8%]; P = .50). The median survival of patients who are DR2+ was slightly, but not significantly, longer than that of the DR2- patients in the ATG group (P = .19). Although the incidence of HLA DR2 was clearly increased in these patients with aplastic anemia, response rates to ATG were not significantly different in the DR2+ and DR2- patients.

Adolescent↗
PubMed1994

Selective depletion of CD8+ cells for prevention of graft-versus-host disease after bone marrow transplantation. A randomized controlled trial.

We performed a prospective randomized, double-blind study to assess the efficacy of selective depletion of CD8+ bone marrow cells in preventing acute graft-versus-host disease (GVHD) in 38 patients undergoing HLA-identical sibling donor bone marrow transplantation for leukemia. All patients received CsA for GVHD prophylaxis. Nineteen patients received marrow depleted of CD8+ cells by ex vivo treatment with anti-leu2, an anti-CD8 mAb and complement; four patients had moderate (grade 1 or 2 acute GVHD) and the only patient who experienced grade 3 manifestations was a technical failure. The control group consisted of 19 patients who received unmodified bone marrow; one patient had grade 1, 4 patients had grade 2, and 10 had grade 3 or 4 acute GVHD. The actuarial incidence of grade > or = 2 acute GVHD was 20 +/- 20% in the CD8-depleted group compared with 80 +/- 18% in the controls (P = 0.004). Death in 5 of the control patients and the single patient in whom CD8 depletion was a technical failure was related to acute GVHD. Graft failure occurred in 2 patients in the CD8-depleted group and in none of the controls. Leukemic relapse occurred in 2 patients receiving CD8-depleted bone marrow and 2 patients in the control group. Seven patients receiving marrow depleted of CD8+ cells are alive and free of leukemia and 9 patients in the control group are alive, 7 of whom remain leukemia-free (P = 0.88). The 3-year actuarial leukemia-free survival is 37 +/- 22% of the CD8-depleted group and 36 +/- 22% for the control group. These results indicate that selective depletion of CD8+ cells from the bone marrow significantly reduces the incidence and severity of acute GVHD.

Adolescent↗
PubMed1994

Characterization of a cell-type-restricted negative regulatory activity of the human granulocyte-macrophage colony-stimulating factor gene.

Human granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulates the proliferation and maturation of normal myeloid progenitor cells and can also stimulate the growth of acute myelogenous leukemia (AML) blasts. GM-CSF is not normally produced by resting cells but is expressed by a variety of activated cells including T lymphocytes, macrophages, and certain cytokine-stimulated fibroblasts and endothelial cells. Production of GM-CSF by cultured AML cells has been demonstrated, and GM-CSF expression by normal myeloid progenitors has been postulated to play a role in myelopoiesis. We have investigated the regulation of expression of GM-CSF in AML cell lines, and our results demonstrate the presence of a strong constitutive promoter element contained within 53 bp upstream of the cap site. We have also identified a negative regulatory element located immediately upstream of the positive regulatory element (within 69 bp of the cap site) that is active in AML cell lines but not T cells or K562 CML cells. Competition transfection and mobility shift studies demonstrate that this activity correlates with binding of a 45-kDa protein.

Base Sequence↗
PubMed1994

Chronic myelogenous leukemia following repeated radiation therapy for histiocytosis X.

Low dose radiotherapy has been used to treat a variety of benign disorders including Histiocytosis X. Ionizing radiation may be leukemogenic with leukemia developing between 3.5 to 11 years after exposure. Twenty to 30% of these leukemias are chronic myelogenous leukemia (CML). In this report the rare development of PH1 + CML 11 years after radiation therapy for Histiocytosis X is recorded.

Adult↗
PubMed1994

Serum stem cell factor levels in patients with aplastic anemia.

Immune suppression of hematopoiesis has been implicated in the pathogenesis of acquired aplastic anemia. Similarly, abnormalities of T cells and bone marrow stromal cells have been reported in aplastic anemia, as has abnormal cytokine production. Stem cell factor (SCF) (also known as kit ligand, mast cell growth factor and Steel factor) is an early acting hematopoietic growth factor that is produced by a variety of mesenchymal cells including bone marrow stromal cells. To determine whether abnormalities in the production of stem cell factor occur in aplastic anemia, we evaluated serum levels of SCF in 25 patients with aplastic anemia. The mean serum levels of SCF in aplastic anemia patients were significantly lower (2.7 +/- 1.1 ng/ml) than those found in a comparable population of 257 normal controls (3.3 +/- 1.1 ng/ml) (P = 0.011). The SCF level did not correlate with patient age, the duration of aplastic anemia or with white blood cell count, platelet count or hematocrit. Although there is no direct evidence that lower SCF serum levels contribute to the pancytopenia seen in this disorder, identification of underlying abnormalities that can result in the deficient production of stromally derived hematopoietic growth factors will be important.

Adolescent↗
PubMed1994

A phase I/II study of interleukin-3 in patients with aplastic anemia and myelodysplasia.

We performed a phase I/II study of recombinant human interleukin-3 (rhIL-3) in 21 patients with aplastic anemia (AA) or myelodysplasia (MDS). Patients received 21-day cycles of IL-3 (0.5, 1.25, 2.5, 5.0, or 10 micrograms/kg/d) by subcutaneous injection followed by a 10- to 14-day washout period. Nineteen patients completed at least one 21-day cycle of IL-3. Frequent toxicities of IL-3 included headache, low-grade fever, and erythema at the injection site; at higher doses, weight gain and peripheral edema was seen. Eleven patients developed eosinophilia. Of the 20 evaluable patients, eight had increases in absolute neutrophil counts (seven with MDS, one with AA) including six of the nine patients receiving > or = 5.0 micrograms/kg/d. One AA patient became transfusion-independent for 8 months, while another AA patient had decreased transfusion requirements. Three patients with MDS had at least a doubling of their platelet count, and another patient experienced a 1.9-fold increase. One patient with RAEB progressed to aleukemic AML by the end of one treatment cycle. IL-3 was well-tolerated, but multilineage effects were seen in only 25% of patients with primary bone marrow failure states (five of 20 evaluable) and more commonly in patients with myelodysplastic syndromes. Its optimal use may be as part of combination hematopoietic growth factor therapy.

Adult↗
PubMed1993

Use of recombinant GM-CSF following allogeneic BMTs for aplastic anemia.

GM-CSF has been used successfully in autologous BMTs, and more recently in patients undergoing allogeneic BMT, for acute or chronic leukemia. We report two patients with hepatitis-related aplastic anemia who received recombinant human GM-CSF following HLA-identical sibling allogeneic BMTs. Both patients were conditioned with CY 200 mg/kg given over 4 days and received GM-CSF at 250 micrograms/m2 beginning 6 h after marrow infusion and continuing daily until the absolute neutrophil count was > 1.0 x 10(9)/l for 2 days. Both patients had prompt engraftment, achieving an absolute neutrophil count of > 0.5 x 10(9)/l on day 13. Neither patient had side-effects attributable to the GM-CSF although one patient developed severe acute GVHD after the cessation of GM-CSF therapy. Our experience suggests that GM-CSF can be safely used in aplastic anemia patients undergoing BMT and that GM-CSF may be useful to decrease the incidence of graft failure associated with less intensive conditioning regimens.

Adult↗