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J L Gabrilove

Publications and source records attributed to J L Gabrilove.

At least 19 recordsLinked to original sources
PubMed1998

Arsenic trioxide and melarsoprol induce programmed cell death in myeloid leukemia cell lines and function in a PML and PML-RARalpha independent manner.

Inorganic arsenic trioxide (As2O3) and the organic arsenical, melarsoprol, were recently shown to inhibit growth and induce apoptosis in NB4 acute promyelocytic leukemia (APL) and chronic B-cell leukemia cell lines, respectively. As2O3 has been proposed to principally target PML and PML-RARalpha proteins in APL cells. We investigated the activity of As2O3 and melarsoprol in a broader context encompassing various myeloid leukemia cell lines, including the APL cell line NB4-306 (a retinoic acid-resistant cell line derived from NB4 that no longer expresses the intact PML-RARalpha fusion protein), HL60, KG-1, and the myelomonocytic cell line U937. To examine the role of PML in mediating arsenical activity, we also tested these agents using murine embryonic fibroblasts (MEFs) and bone marrow (BM) progenitors in which the PML gene had been inactivated by homologous recombination. Unexpectedly, we found that both compounds inhibited cell growth, induced apoptosis, and downregulated bcl-2 protein in all cell lines tested. Melarsoprol was more potent than As2O3 at equimolar concentrations ranging from 10(-7) to 10(-5) mol/L. As2O3 relocalized PML and PML-RARalpha onto nuclear bodies, which was followed by PML degradation in NB4 as well as in HL60 and U937 cell lines. Although melarsoprol was more potent in inhibiting growth and inducing apoptosis, it did not affect PML and/or PML-RARalpha nuclear localization. Moreover, both As2O3 and melarsoprol comparably inhibited growth and induced apoptosis of PML+/+ and PML-/- MEFs, and inhibited colony-forming unit erythroid (CFU-E) and CFU granulocyte-monocyte formation in BM cultures of PML+/+ and PML-/- progenitors. Together, these results show that As2O3 and melarsoprol inhibit growth and induce apoptosis independent of both PML and PML-RARalpha expression in a variety of myeloid leukemia cell lines, and suggest that these agents may be more broadly used for treatment of leukemias other than APL.

Animals↗
PubMed1998

Recurrent Cushing's syndrome due to recurrent adrenocortical tumor--fragmentation or tumor in ectopic adrenal tissue?

A 33-yr-old woman was found to have Cushing's syndrome due to a left adrenal cortical tumor. The tumor and the surrounding adrenal gland were removed intact and in toto. Four years later, she noticed recurrent symptoms of Cushing's syndrome, and 6 yr postoperatively, an adrenal tumor was demonstrable on computed tomography. Fourteen years after the initial procedure, a left adrenal tumor, presumably arising in ectopic adrenal tissue, was removed with relief of her symptoms of Cushing's syndrome. The site and functional capacity of ectopic adrenal tissues are reviewed.

Adrenal Cortex Neoplasms↗
PubMed1998

Antitumor activity of actinonin in vitro and in vivo.

Actinonin, an antibiotic and CD13/aminopeptidase N (APN) inhibitor, has been shown to be cytotoxic to tumor cell lines in vitro. We investigated the antiproliferative effects of actinonin on human and murine leukemia and lymphoma cells. Actinonin inhibited growth of NB4 and HL60 human cell lines and AKR mouse leukemia cells in vitro with an IC50 of about 2-5 micrograms/ml. The inhibitory effect on CD13-positive cells was not blocked by pretreatment with the anti-CD13/APN monoclonal antibody F23, which binds with high affinity to the active site of CD13/APN and blocks its enzymatic activity. Moreover, F23 alone was not inhibitory to CD13-positive cells. Furthermore, a similar inhibitory IC50 of actinonin was seen in the CD13-negative cell lines RAJI and DAUDI human lymphoma. These data suggest that the inhibitory effect of actinonin is not mediated by inhibition of CD13/APN. Cell cycle analysis showed that actinonin induces a G1 arrest in HL60 and NB4 cells; apoptosis was observed in 20-35% of the cells as measured by intracellular flow cytometry. To assess whether these effects could be seen in vivo, the effect of actinonin on the syngeneic AKR mouse leukemia model was evaluated. Actinonin showed dose-dependent antitumor effects on AKR leukemia in vivo, resulting in a survival advantage. In conclusion, apoptosis, growth inhibition, and therapeutic effects in vivo are induced by actinonin and are not likely to be mediated by CD13/APN.

Animals↗
PubMed1997

The novel cyclin-dependent kinase inhibitor flavopiridol downregulates Bcl-2 and induces growth arrest and apoptosis in chronic B-cell leukemia lines.

Flavopiridol is a novel, potent inhibitor of cyclin-dependent kinases (CDK). This synthetic flavone has been reported to exhibit antitumor activity in murine and human tumor cell lines in vitro and in vivo and is currently undergoing clinical phase I evaluation. In the present study, 1 Epstein-Barr virus (EBV)-transformed B-prolymphocytic cell line (JVM-2), 1 EBV-transformed B-CLL cell line (I83CLL), and 1 non-EBV transformed B-CLL cell line (WSU-CLL) were used as targets. Treatment of the cells with flavopiridol (100 nmol/L to 400 nmol/L) led to a marked dose- and time-dependent inhibition of cell growth and survival as determined using trypan blue exclusion. Morphologic analysis showed characteristic apoptotic changes such as chromatin condensation and fragmentation, membrane blebbing, and formation of apoptotic bodies. Furthermore, quantitative assessment of apoptosis-associated DNA strand breaks by in situ TdT labeling showed that a significant number of flavopiridol-treated cells underwent apoptosis. These cellular effects were associated with a significant decrease in bcl-2 expression as observed by Northern and Western blotting. The results showed that flavopiridol downregulates bcl-2 mRNA and bcl-2 protein expression within 24 hours. Genistein and quercetin, two flavonoids that do not inhibit CDKs, did not affect bcl-2 expression. These data suggest an additional mechanism of action of this new flavone which might be useful as an agent in the treatment of chronic lymphoid malignancies.

Apoptosis↗
PubMed1997

Comparative activity of melarsoprol and arsenic trioxide in chronic B-cell leukemia lines.

Inorganic arsenic trioxide (As2O3) was recently shown to induce apoptosis in NB4 promyelocytic leukemic cells. We have investigated the effects of the organic arsenical, melarsoprol (a drug used for treatment of trypanosomiasis), upon induction of apoptosis in cell lines representative of chronic B-cell lymphoproliferative disorders. An Epstein-Barr virus (EBV)-transformed B-prolymphocytic cell line (JVM-2), an EBV-transformed B-cell chronic lymphocytic leukemia (B-CLL) cell line (I83CLL), and one non-EBV-transformed B-CLL cell line (WSU-CLL) were used as targets. Dose-response experiments with melarsoprol (10(-7) to 10(-9) mol/L) were performed over 96 hours. Unexpectedly, we found that melarsoprol caused a dose- and time-dependent inhibition of survival and growth in all three cell lines. In contrast, As2O3 at similar concentrations had no effect on either viability or growth. After 24 hours, all three cell lines treated with melarsoprol (10(-7) mol/L) exhibited morphologic characteristics of apoptosis. We also observed prominent concentration-dependent downregulation of bcl-2 mRNA after 24 hours of exposure to melarsoprol in WSU-CLL, I83CLL, and JVM-2 cells. Decrease of bcl-2 protein expression was also observed in all three cell lines, whereas As2O3 had no effect on this parameter. We conclude that melarsoprol may inhibit the growth of lymphoid leukemic cell by promoting programmed cell death. Results of these studies suggest that melarsoprol shows promising therapeutic activity in these diseases, and a study to evaluate clinical effects of this drug has been initiated.

Antineoplastic Agents↗
PubMed1997

Basic fibroblast growth factor (bFGF) upregulates the expression of bcl-2 in B cell chronic lymphocytic leukemia cell lines resulting in delaying apoptosis.

Basic fibroblast growth factor (bFGF) is a pleiotropic cytokine which has recently been shown to delay fludarabine-induced apoptosis in B cell chronic lymphocytic leukemia (B-CLL) cells. To investigate the potential mechanism of bFGF-mediated delay of apoptosis, two EBV-transformed B prolymphocytic cell lines (JVM-2, JVM-13), one EBV-transformed B-CLL cell line (I83CLL), and one non-EBV-transformed B-CLL cell line (WSU-CLL) were used as a model for chronic lymphoid malignancies. Viability data of cells treated with fludarabine alone or in combination with bFGF demonstrated that the addition of bFGF to the cells resulted in prolonged survival. Quantitative assessment of apoptosis-associated DNA strand breaks by in situ TdT labeling showed a protective effect of bFGF on fludarabine-treated cells. The potential effect of bFGF on bcl-2 mRNA expression was analyzed by Northern blotting. Stimulation with bFGF led to a time-dependent accumulation of bcl-2 specific mRNA in all three cell lines. Maximal levels of bcl-2 mRNA expression were detected after 8 h in JVM-2, and after 18 h in JVM-13 and I83CLL. Intracellular bcl-2 protein was also found to be increased upon bFGF stimulation in both EBV- and non-EBV-transformed cells. In addition, exposure of cells from three patients with B-CLL to bFGF showed an upregulation of bcl-2 protein after 4-8 h. Our data demonstrate that bFGF upregulates the expression of bcl-2 in these cells, suggesting that this increase in bcl-2 expression may play a role in the delay of fludarabine-induced apoptosis.

Apoptosis↗
PubMed1997

Low level expression of basic FGF upregulates Bcl-2 and delays apoptosis, but high intracellular levels are required to induce transformation in NIH 3T3 cells.

We investigated the roles of basic fibroblast growth factor (bFGF) in the transformation and survival of NIH 3T3 cells. We constructed NIH 3T3-derived cell lines expressing human bFGF using retroviral gene transfer with an N2-based vector. Clonally derived cell lines containing a single copy of the vector overexpress bFGF mRNA and produce more immunoreactive protein (0.407 +/- 0.010-3.028 +/- 0.087 ng bFGF/10(6) cells) which is biologically active than nontransduced (0.151 +/- 0.013 ng bFGF/10(6) cells) or N2-transduced (0.211 +/- 0.029 ng bFGF/10(6) cells) NIH 3T3 cells. All cells producing excess amounts of bFGF achieve greater density at confluence, show delayed apoptosis and increased survival and have elevated intracellular levels of Bcl-2. However, only cells expressing from 8-15 times background levels of bFGF are phenotypically transformed. The transformed cells form dense foci at confluence, have decreased adherence to tissue culture plates and grow colonies in soft agar. Exogenous bFGF induces higher Bcl-2 levels in a dose dependent manner and recapitulates the antiapoptotic effects of the overexpressed species but fails to induce changes associated with the transformed phenotype. In this study, we demonstrate a dissociation between phenotypic transformation secondary to bFGF overexpression and upregulation of cellular Bcl-2 that correlates with a delay in programmed cell death. Although low level expression of bFGF or exogenous bFGF is sufficient to upregulate Bcl-2 and delay apoptosis, high intracellular levels are required for cellular transformation. These data suggest that overexpression of bFGF modulates cellular transformation and Bcl-2-mediated inhibition of apoptosis through alternate molecular mechanisms.

3T3 Cells↗
PubMed1997

The role of sex steroids in the pathogenesis and maintenance of benign prostatic hyperplasia.

BACKGROUND: It has long been suspected that sex steroids play a key role in the pathogenesis of benign prostatic hyperplasia (BPH). Prostatic diseases do not occur in males castrated before puberty or in males with heritable disorders of androgen production or action. Both estrogens and androgens have been shown to induce BPH in experimental animals. METHODS: Clinical studies utilizing hormonal therapies to treat BPH were reviewed. Studies that used total medical castration therapy via the use of a long-acting gonadotropin-releasing hormone (GnRH agonist), partial androgen blockade via the use of the 5 alpha-reductase inhibitor finasteride, and estrogen blockade (via the use of aromatase inhibitors) were analyzed. RESULTS AND CONCLUSIONS: Both the GnRH agonists and finasteride result in prostatic size reduction and alleviate symptoms in some patients. Both therapies are more effective in men with larger prostates (> 40 cc). Finasteride is less efficacious in terms of size reduction than the GnRH agonists but also has fewer side effects. To date, clinical trials with aromatase inhibitors have not yielded dramatic positive results in the treatment of BPH.

Antineoplastic Agents, Hormonal↗
PubMed1994

Stem cell factor and basic fibroblast growth factor are synergistic in augmenting committed myeloid progenitor cell growth.

Stem cell factor (SCF) and basic fibroblast growth factor (bFGF) are hematopoietic cytokines produced by bone marrow stromal cells. It is known that, although SCF and bFGF have limited clonogenic activity on their own, they can augment colony-stimulating factor (CSF)-mediated progenitor cell growth. Because these factors are both sequestered by stromal cells, we examined their interaction on progenitor cell growth in conjunction with granulocyte-macrophage-CSF (GM-CSF). In this study, we show that clonogenic growth derived from low-density bone marrow cells stimulated by GM-CSF is significantly augmented (P < .001) in the presence of maximal (100 ng/mL) concentrations of SCF in combination with 100 ng/mL of bFGF. When CD34+ cells are used, the synergistic effect of bFGF and SCF for GM-CSF-mediated progenitor cell growth is further increased, resulting in as much as a sevenfold increase in detectable colony-forming units granulocyte-macrophage (P < .001). These data suggest that the synergistic activity of bFGF and SCF is mediated directly on hematopoietic precursors. These observations suggest that bFGF and SCF, concentrated locally on stromal cell surfaces, might interact in concert with other hematopoietic cytokines to regulate stem cell proliferation and differentiation in hematopoietic niches in the bone marrow.

Antigens, CD↗
PubMed1994

Phase I trial of intravenous and intraperitoneal administration of granulocyte-macrophage colony-stimulating factor.

To assess the toxicity, pharmacokinetics, and local and systemic effects of the intraperitoneal (i.p.) administration of granulocyte-macrophage colony-stimulating factor (GM-CSF) at various dosages, 13 patients with predominantly i.p. malignancies refractory to standard chemotherapy were studied. GM-CSF was administered intravenously (i.v.) for 5 consecutive days; 21 days later the same dosage of GM-CSF was administered i.p. for 5 consecutive days. Four dosage levels were studied: 1, 2, 4, and 8 micrograms/kg/day. GM-CSF was well tolerated after i.v. and i.p. administration at doses up to 8 micrograms/kg/day. A transient fall followed by an elevation of circulating white cells was observed over a 24-h period after both i.v. and i.p. GM-CSF administration (mean minimum +/- SE as % baseline): 38 +/- 8% at 30 min after i.v. administration, 21 +/- 5% at 60 min after i.p. administration; mean maximum: 220 +/- 41% at 6 h after i.v. administration, 202 +/- 39% at 12 h after i.p. administration). The magnitude and time course of these changes were very similar for the two routes despite an up to 400-fold difference in serum GM-CSF levels at the same time points. Changes in leukocyte count and differential and neutrophil function were also similar over the 3-week period after both i.v. and i.p. administration. In the only patient who had i.p. GM-CSF levels assayed, i.p. administration achieved high levels of GM-CSF in peritoneal fluid (Cmax 343 ng/ml) with maintenance of high concentrations over 24 h (C24h 128 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Basic fibroblast growth factor promotes the proliferation of human megakaryocyte progenitor cells.

Basic fibroblast growth factor (bFGF), a multifunctional growth factor produced by bone marrow stromal cells, is known to be a potent modulator of hematopoiesis. Because bFGF is present in both human megakaryocytes (MKs) and platelets, we have hypothesized that this growth factor might affect human megakaryocytopoiesis. To test this hypothesis, either low density bone marrow (BM) cells (LDBM), a human BM subpopulation (CD34+ DR+) enriched for the colony-forming unit megakaryocyte (CFU-MK) or a BM subpopulation (CD34+ DR-) enriched for the more primitive burst-forming unit megakaryocyte (BFU-MK) were assayed in the presence of this growth factor. The effect of bFGF on MK colony formation differed according to the cell population assayed. bFGF alone had on MK colony-stimulating activity (MK-CSA) when either CD34+ DR+ or CD34+ DR- BM cells were cloned, but exhibited MK-CSA equivalent to that of interleukin-3 (IL-3) when LDBM cells were used as the target cell population. The MK-CSA of bFGF was inhibited by the addition of neutralizing antisera to either IL-3 and/or granulocyte-macrophage colony-stimulating factor (GM-CSF) but not IL-6. The addition of excess amounts of either IL-3 or GM-CSF to cultures containing bFGF plus anti-IL-3 or anti-GM-CSF reversed the inhibition by the corresponding antisera. The addition of bFGF and IL-3 to assays containing CD34+ DR+ or CD34+ DR- cells increased the size of both CFU-MK- and BFU-MK-derived colonies, respectively, when compared with assays containing IL-3 alone. This increase in MK colony size mediated by bFGF was not affected by addition of either an anti-GM-CSF or anti-IL-6 neutralizing antisera. When LDBM cells were assayed, bFGF alone increased CFU-MK-derived colony size when compared with control values. However, this potentiation of MK colony size by bFGF could be reversed by the addition of either anti-IL-3 or anti-GM-CSF but not anti-IL-6 antisera. In addition, the effects of bFGF and IL-3 on the size of MK colonies cloned from LDBM were not additive. These results suggest that bFGF affects human megakaryocytopoiesis by directly promoting MK progenitor cell proliferation and stimulating BM accessory cells to release growth factor(s) with MK-CSA, such as IL-3 and GM-CSF. We conclude that bFGF, likely produced by cellular components of the BM microenvironment, plays an important role in the control of human megakaryocytopoiesis.

Antibodies↗
PubMed1993

Interleukin-1 modulation of cytokine receptors on human neutrophils: in vitro and in vivo studies.

Interleukin-1 (IL-1) modulation of cytokine receptors (human IL-1 receptor [hIL-1R], human granulocyte colony-stimulating factor [hG-CSFR], human granulocyte-macrophage CSF receptor [hGM-CSFR], and human tumor necrosis factor receptor [hTNFR]) on human neutrophils was studied both in vitro and in vivo. In vitro, incubation of neutrophils with IL-1 at 37 degrees C for 0.5 or 8 hours caused a reduction of IL-1 binding in a dose-dependent manner, but did not demonstrably affect binding of the other cytokines tested. In vivo, neutrophils from patients with gastrointestinal malignancies who were participating in a clinical trial of recombinant human IL-1 beta (rhIL-1 beta) demonstrated modulation of cytokine receptors in an IL-1 beta dose- and time-dependent manner. At the two highest dose levels of IL-1 beta (0.068 and 0.1 microgram/kg), reduction (> 40%) of G-CSF binding and elevation (twofold to sixfold) of IL-1 binding to neutrophils was observed after 1 hour and 4 to 8 hours, respectively. In addition, IL-1 beta rapidly elevated G-CSF and glucocorticoid levels in plasma. Patients at the lowest dose level (0.002 microgram/kg) had a less dramatic change in these parameters. Further in vitro studies showed that synthetic glucocorticoids and G-CSF synergistically up-modulated IL-1 binding to neutrophils in a dose- and time-dependent manner. Scatchard analysis of binding data showed that this in vitro synergistic modulation was due to an increase in receptor numbers, rather than an increase in binding affinity. In addition, both human umbilical cord blood and bone marrow neutrophils responded to G-CSF and dexamethasone (Dex) with a superadditive increase in IL-1 binding. Therefore, one of mechanisms for IL-1 up-modulation of IL-1R on human neutrophils in vivo was due to the fact that IL-1 rapidly elevates serum levels of G-CSF and glucocorticoids.

Animals↗
PubMed1993

Basic fibroblast growth factor counteracts the suppressive effect of transforming growth factor-beta 1 on human myeloid progenitor cells.

We have previously shown that basic fibroblast growth factor (bFGF) is mitogenic for human bone marrow stromal cells and enhances myelopoiesis in human long-term bone marrow culture. In the present study, we examined the mechanism by which bFGF enhances granulopoiesis. We observed that bFGF significantly abrogated the inhibitory effect of transforming growth factor-beta 1 (TGF-beta 1) on granulocyte-macrophage colony-stimulating factor (GM-CSF)-supported progenitor cell growth (P = .009). The partial reversal of TGF-beta 1-mediated suppression was dependent on the dose of bFGF used. In addition, we noted that the inclusion of neutralizing antibody to TGF-beta 1 significantly augmented the clonogenic response to GM-CSF. We have also shown that 10 ng/mL or 100 ng/mL of bFGF resulted in a 30% to 100% increase in GM-CSF-mediated progenitor cell growth (P = .0001). These data suggest that bFGF may enhance myelopoiesis by modulating the inhibitory response to TGF-beta 1.

Antibodies↗
PubMed1993

Dose-intensification of MVAC with recombinant granulocyte colony-stimulating factor as initial therapy in advanced urothelial cancer.

PURPOSE: This study was undertaken to define an escalated dose schedule of methotrexate, vinblastine, doxorubicin, and cisplatin (E-MVAC) with hematopoietic growth-factor support, to define the ability to deliver E-MVAC with recombinant human granulocyte colony-stimulating factor (rhG-CSF) on 21- and 14-day schedules, and to assess the ability of rhG-CSF to maintain dose-intensity over four cycles of chemotherapy. PATIENTS AND METHODS: Twenty-three patients with transitional-cell carcinoma of the urothelium received E-MVAC in a phase I investigation. Patients were treated on an every-21-day (n = 19) or every-14-day schedule of administration (n = 4), with rhG-CSF support. Delivered dose-intensity was calculated at the completion of four cycles of therapy relative to the planned administration of conventional MVAC (relative dose-intensity [RDI]). Peripheral-blood progenitor cell kinetics in these patients were studied prospectively. RESULTS: Overall, the delivered RDI was 33% higher than the previously reported delivered dose-intensity of MVAC without hematopoietic support (140% for doxorubicin, 51% for cisplatin). Dose-intensity was well maintained through three cycles of therapy, after which leukopenia and thrombocytopenia became dose-limiting. Sixty-nine percent of patients with measurable disease responded, four (25%) with complete remissions. In five patients treated beyond the maximally tolerated dose (MTD), a 50- to 200-fold increase in G-CSF, granulocyte-macrophage CSF (GM-CSF), and interleukin-3 (IL-3)-responsive peripheral-blood progenitor cells over baseline was observed after 9 days of rhG-CSF administration. CONCLUSION: These findings demonstrate the feasibility and limitations of dose intensification of M-VAC with rhG-CSF. While the overall impact of the increased drug administration can only be assessed in randomized comparisons, the results of the present trial suggest that escalations of the components of the four-drug regimen are unlikely to improve significantly the outcome for patients with advanced urothelial tract tumors.

Adolescent↗
PubMed1992

Regulation of proteolytic activity in human bone marrow stromal cells by basic fibroblast growth factor, interleukin-1, and transforming growth factor beta.

Plasminogen activators (PAs) and/or plasmin may be involved in hematopoietic regulation. These enzymes release biologically relevant cytokines such as basic fibroblast growth factor (bFGF) from matrix and cell surfaces. In addition, transforming growth factor beta (TGF beta) and interleukin-1 beta (IL-1 beta) are converted from inactive to active forms by plasmin. Therefore, we studied the regulation of PAs and their specific inhibitors, PA inhibitor 1 (PAI-1) and PA inhibitor 2 (PAI-2), in human bone marrow stromal fibroblasts by IL-1 beta, bFGF, and TGF beta. All three cytokines stimulated PA secretion. IL-1 beta at 10(4) U/mL increased urokinase (u-PA) levels approximately 10-fold, bFGF at 0.2 ng/mL also increased production 10-fold, but increased predominantly tissue PA (t-PA) expression. TGF beta at 0.2 ng/mL increased u-PA production up to 300-fold. PAI-1 and PAI-2 are also regulated by these cytokines. IL-1 beta decreased PAI-1 levels by 50% and stimulated PAI-2 levels sixfold. bFGF had minimal effects on PAI-1 and TGF beta increased PAI-1 levels twofold. Neither of these agents had an effect on PAI-2 levels. Thus, three cytokines relevant to bone marrow physiology regulate PA and inhibitor production by human bone marrow stromal fibroblasts. In this manner PA and plasmin generation in specific microenvironments in the bone marrow may be one of the factors orchestrating the complex series of events, which results in an efficient exquisitely regulated hematopoietic process.

Bone Marrow↗