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J D Jackson

Publications and source records attributed to J D Jackson.

At least 37 records · Page 2Linked to original sources
PubMed1997

A hexameric phosphorothioate oligonucleotide telomerase inhibitor arrests growth of Burkitt's lymphoma cells in vitro and in vivo.

A phosphorothioate oligonucleotide (PS-ODN) with sequence identical to the repeat sequence of the mammalian telomere, 5'-d(TTAGGG)-3', was incubated with a Burkitt's lymphoma-derived (OMA-BL1) cell line. This hexanucleotide inhibits telomerase activity in cell lysates, lengthens cell doubling time, and induces apoptosis. Concatenated repeats (12-, 18-, and 24-mers) of the 5'-d(TTAGGG)-3' motif induce similar cellular responses. Scrambled sequences do not efficiently inhibit telomerase activity or significantly alter cell growth and viability. The in vivo efficacy of this PS-ODN was evaluated in a xenograft human-nude mouse model. Once tumors were established these animals were administered the telomere mimic, 5'-d(TTAGGG)-3', a control scrambled sequence 5'-d(TGTGAG)-3', or saline for 14 days via a subcutaneous osmotic pumps in a blinded study monitoring tumor size with dose and time. A significant decrease in tumor size was observed in animals given 50 micrograms/mouse/day 5'-d(TTAGGG)-3', but not following 5'-d(TGTGAG)-3', relative to the saline-treated animals. The antitumor activity of the 6-mer telomere mimic demonstrated a dose dependency including a reduction in metastatic nodules in the spleen. No activity was observed with the scrambled controls. In addition to antitumor activity we observed an increase in the mouse hematopoietic progenitor cell populations, BFU-e and CFU-GM. These results demonstrated the effects of a short hexameric oligonucleotide telomere mimic in vitro and in vivo and the potential utility of short oligonucleotides as telomerase inhibitors.

Animals↗
PubMed1997

Ex vivo treatment of bone marrow with phosphorothioate oligonucleotide OL(1)p53 for autologous transplantation in acute myelogenous leukemia and myelodysplastic syndrome.

Effective ex vivo purging techniques can decrease the likelihood of infusing bone marrow contaminated with leukemic cells during autologous transplantation. In preliminary studies, OL(1)p53, a 20-mer phosphorothioate oligonucleotide directed against p53 mRNA, decreased the number of acute myelogenous leukemia (AML) cells in vitro, suggesting a possible role for OL(1)p53 in purging bone marrow harvests of leukemia cells. To demonstrate that OL(1)p53 was nontoxic to hematopoietic progenitor cells, normal bone marrow cells were incubated with 10 microM OL(1)p53 for 36 h, and hematopoietic progenitor cell survival was determined by in vitro colony assays. OL(1)p53 had no toxic effect on the growth of either myeloid (CFU-GM) or erythroid (BFU-E) progenitor cells. OL(1)p53 was then used to ex vivo purge bone marrow harvests from nine patients with either AML or myelodysplastic syndrome (MDS). Bone marrow cells were incubated with 10 microM OL(1)p53 for 36 h before transplantation. The median times posttransplantation for the patient to recover an absolute neutrophil count greater than 0.5 x 10(9)/L and a platelet transfusion independence were 30 days and 56 days, respectively. Incubation of bone marrow cells with OL(1)p53 had no detrimental effect on the growth of hematopoietic progenitor cells, and transplantation of autologous bone marrow cells treated with the phosphorothioate oligonucleotide, OL(1)p53, resulted in successful recovery of circulating neutrophils following high-dose therapy in patients with AML or MDS. The data show that OL(1)p53 can be used safely to purge autologous bone marrow harvests from patients with leukemia.

Adult↗
PubMed1997

Allogeneic-blood stem-cell collection following mobilization with low-dose granulocyte colony-stimulating factor.

PURPOSE: The optimal dose of granulocyte colony-stimulating factor (G-CSF) for mobilization of allogeneic-blood stem cells (AlloBSC) has yet to be determined. As part of a prospective trial, 41 related human leukocyte antigen (HLA)-matched donors had blood cells mobilized with G-CSF at 5 micrograms/kg/d by subcutaneous administration. The purpose of this trial was to monitor adverse effects during G-CSF administration and stem-cell collection, to determine the optimal timing for stem-cell collection, and to determine the cellular composition of stem-cell products following G-CSF administration. PATIENTS AND METHODS: The median donor age was 42 years. Apheresis began on day 4 of G-CSF administration. At least three daily 12-L apheresis collections were performed on each donor. A minimum of 1.0 x 10(6) CD34+ cells/kg (recipient weight) and 8.0 x 10(8) mononuclear cells/kg were collected from each donor. All collections were cryopreserved in 5% dimethyl sulfoxide and 6% hydroxyethyl starch. RESULTS: Toxicities associated with G-CSF administration and the apheresis process included myalgias/arthralgias (83%), headache (44%), fever (27%), and chills (22%). The median baseline platelet count of 242 x 10(4)/ mL decreased to 221, 155, and 119 x 10(6)/mL on days 4, 5, and 6 of G-CSF administration, respectively. Median numbers of CD34+ cells in collections 1, 2, and 3 were 1.99, 2.52, and 3.13 x 10(6)/kg, respectively. The percentage and total number of CD4+, CD8+, and CD56+/CD3- cells remained relatively constant during the three collections. Median total numbers of cells were as follows: CD34+, 7.73 x 10(6)/kg; and lymphocytes, 6.93 x 10(8)/kg. CONCLUSION: Relatively low doses of G-CSF can mobilize sufficient numbers of AlloBSC safely and efficiently.

Adult↗
PubMed1997

Hematopoietic recovery after allogeneic blood stem-cell transplantation compared with bone marrow transplantation in patients with hematologic malignancies.

PURPOSE: To compare hematopoietic recovery, duration of hospitalization, and 100-day survival in patients who received allogeneic-blood stem cells (BSC) or conventional allogeneic bone marrow transplantation (BMT). PATIENTS AND METHODS: From December 1994 to August 1995, 21 patients participated in a phase II study of allogeneic BSC transplantation. Cells mobilized with granulocyte colony-stimulating factor (G-CSF; 5 micrograms/kg/ d) were collected from human leukocyte antigen (HLA)-matched related donors and cryopreserved. Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporine and methotrexate. G-CSF (10 micrograms/kg/d) was administered posttransplant. The outcomes were compared with 22 identically treated historical patients who received allogeneic BMT. RESULTS: The median infused CD34+ cell and granulocyte-macrophage colony-forming unit (CFU-GM) content were 7.73 x 10(4)/kg and 41.6 x 10(4)/kg, respectively. The median time to a neutrophil count greater than 500/ microL was 11 days after BSC and 16.5 days after BMT (P = .0003). A trend toward faster platelet and RBC recovery after BSC was observed. BSC patients received fewer platelet transfusions: 10 versus 19 (P = .015). The median length of hospitalization was shorter after BSC transplantation: 25 versus 31.5 days (P = .0243). The 100-day survival rates were similar: 83% after BSC and 75% after BMT (P = .3585). The incidence of acute GVHD grade II to IV was 57% and 45% for BSC and BMT, respectively (P = .4654). CONCLUSION: In comparison to BMT, allogeneic BSC transplantation may result in faster hematopoietic recovery, shorter hospital stay, and similar early survival. Whether allogeneic BSC are superior to bone marrow needs to be determined in randomized trials.

Adult↗
PubMed1996

Sequences within and flanking hypersensitive sites 3 and 2 of the beta-globin locus control region required for synergistic versus additive interaction with the epsilon-globin gene promoter.

The locus control region is required for high-level, position-independent expression of mammalian beta-globin genes. It is marked by five major DNase hypersensitive sites (HSs) in a 16 kb region of chromatin, and the protein-DNA complexes that form these HSs may interact in a holocomplex that carries out the full function of the locus control region. Previous studies showed that a large rabbit DNA fragment containing both HS2 and HS3 in their native sequence context and spacing produced a much larger increase in expression of a linked reporter gene than the sum of the largest effects observed with DNA fragments containing HS2 or HS3 individually. To test whether this reflected a synergistic interaction between the 200-400 bp cores of the HSs or if this effect required additional sequences outside the cores, combinations of different restriction fragments containing HS2 or HS3 were tested for their ability to increase the expression of a hybrid epsilon-globin-luciferase reporter gene in transfected K562 cells. The results show that the human HS2 and HS3 cores do not interact either additively or synergistically with the reporter gene when juxtaposed, and separation by spacer DNA has little effect on their function. Fragments of human DNA containing cores plus flanking sequences for HS3 or HS2 show an additive effect in combination, whereas homologous fragments of rabbit DNA containing HS3 and HS2 interact synergistically. At least part of this difference localizes to the rabbit DNA fragment containing HS3, which can interact synergistically with the human DNA fragment containing HS2. The region 5' to the HS3 core plays a role both in the cooperative interaction observed with the rabbit DNA fragment and the domain-opening observed with the human DNA. A minor DNase HS maps to this region, and the pattern of sequence conservation is consistent with some difference in function between species.

Animals↗
PubMed1996

Use of gene therapy to suppress the antigen-specific immune responses in mice to an HLA antigen.

Hematopoietic chimerism has been used in the laboratory to induce life-long immunologic tolerance to donor antigens. The present study demonstrates that mice transplanted with autologous bone marrow cells retrovirally transduced to express HLA-A2.1 develop a significantly depressed immune response to this antigen while retaining normal reactivity to HLA-B7. Retrovirus-mediated transduction was performed using whole bone marrow-producer cell coculture. This approach did not result in significant gene transfer into hematopoietic progenitor cells. Despite this, the antibody response to HLA-A2.1 in mice reconstituted with genetically modified BMC was completely suppressed three months following bone marrow transplantation. Cell-mediated immunity to HLA-A2.1 was partially suppressed in three-fourths of animals tested three months later, although one animal had a CTL profile similar to that an of HLA-A2.1 transgenic mouse. Complete suppression of the antibody-mediated immune response occurred when only one-third of mice had evidence of the introduced genes in their spleen and one-tenth had the introduced sequences in their circulating WBCs by PCR. In conclusion, engineering of BMC to express donor MHC genes may be an alternative to xenogeneic BMT to induce chimerism and tolerance. More efficient transduction of bone marrow progenitor cells may result in more persistent gene expression and long-lasting transplantation tolerance in recipients of genetically modified bone marrow. Successful application of this technology may also be useful in altering immune responses to other external and self antigens.

Animals↗
PubMed1996

Role of DNA sequences outside the cores of DNase hypersensitive sites (HSs) in functions of the beta-globin locus control region. Domain opening and synergism between HS2 and HS3.

The roles of each DNase hypersensitive site (HS), and the DNA sequences between them, in the activity of the locus control region of the mammalian beta-globin gene domain were examined by placing human and rabbit restriction fragments containing the cores of HS2, HS3, HS4, and HS5, along with varying amounts of flanking DNA, upstream of a hybrid epsilon-globin-luciferase reporter gene and testing for effects on expression both prior to and after integration into the chromosomes of K562 cells, a human erythroid cell line. Prior to integration, fragments containing HS2 enhanced expression to the greatest extent, and the modest enhancement by some fragments containing HS3 correlated with the presence of a well-conserved binding site for AP1/NFE2. The stronger effects of larger locus control region DNA fragments in clones of stably transfected cells indicates a role for sequences outside the HS cores after integration into the genome. The strong effect of a 1.9-kilobase HindIII fragment containing HS3 after, but not prior to, integration argues for the presence of a chromatin domain-opening activity. Use of a rabbit DNA fragment containing both HS2 and HS3 demonstrated a synergistic interaction between the two HSs when their natural context and spacing are preserved.

Animals↗
PubMed1996

In vivo haemoprotective activity of tetrapeptide AcSDKP combined with granulocyte-colony stimulating factor following sublethal irradiation.

We report that acetyl-N-Ser-Asp-Lys-Pro (AcSDKP), which removes progenitor cells from cell cycle, in combination with granulocyte-colony stimulating factor (G-CSF) can significantly improve myelorestoration following irradiation (7 Gy). Peripheral blood, spleen and bone marrow (BM) cell recovery and progenitor cell reconstitution [IL-3-responsive colony-forming cells (CFC) and high proliferative potential colony-forming cells (HPP-CFC)] were studied. Studies on the optimal schedule of AcSDKP administration revealed maximal effects on progenitor cells when AcSDKP was administered as a continuous infusion for 3 d starting 24 h prior to irradiation and used in combination with G-CSF. The numbers of CFC and HPP-CFC in the BM were significantly increased following irradiation in mice receiving AcSDKP and G-CSF as compared to either drug alone. The numbers of CFC in the spleen were significantly increased in mice receiving AcSDKP and G-CSF on days 10 and 14 as compared to AcSDKP alone, but not G-CSF. Similarly, CFC and HPP-CFC in the spleen were significantly increased in mice receiving AcSDKP and G-CSF on day 18 as compared to mice receiving PBS and G-CSF. These studies suggest that AcSDKP in combination with G-CSF may have potential for the protection of progenitor cells in patients undergoing intensive chemo- and/or radiotherapy.

Animals↗
PubMed1996

Phase I trial of recombinant fusion protein PIXY321 for mobilization of peripheral-blood cells.

PURPOSE: Mobilization of peripheral-blood cells (PBC) with cytokines alone results in rapid hematopoietic recovery and avoids the potential morbidity associated with mobilization by chemotherapy. PIXY321, a fusion protein that consists of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3), has enhanced hematopoietic colony-forming activity as compared with individual or equimolar combinations of the two cytokines. A phase I trial of PIXY321 for mobilization of PBC in patients with malignant lymphoma was performed. PATIENTS AND METHODS: Thirteen patients with malignant lymphoma who were eligible for high-dose therapy (HDT) were enrolled onto the trial. All patients were ineligible for autologous bone marrow transplantation due to overt metastatic disease in the marrow or to severe marrow hypocellularity. PIXY321 was administered at three dose levels of 250, 500, and 750 micrograms/m2/d by continuous infusion until completion of PBC collections. Collections were initiated when the WBC count was greater than 10 x 10(9)/L or 4 days after the initiation of PIXY321, whichever came first. Collections were continued until a minimum of 6.5 x 10(8) mononuclear cells (MNC)/kg patient weight were obtained. RESULTS: PIXY321 was generally well tolerated. Side effects associated with PIXY321 administration did not exceed grade 2 and included fever (85%), chills/sweats (54%), myalgias (38%), fatigue (31%), nausea/vomiting (31%), headache (31%), edema (23%), and rhinorrhea (23%). The median numbers of colony-forming units-granulocyte/macrophage (CFU-GM) in the graft products for the three dose levels were 0.31, 2.94, and 2.88 x 10(4)/kg, respectively; the median numbers of burst-forming units-erythroid (BFU-e) were 0.20, 6.94, and 12.78 x 10(4)/kg, and the median numbers of CD34+ cells were 2.30, 0.74, and 0.39 x 10(6)/kg. Following transplantation, the median times to an absolute neutrophil count (ANC) > 0.5 x 10(9)/L were 12, 15, and 12 days, respectively, and the median times to platelet transfusion independence were 30, 19, and 15 days. CONCLUSION: PIXY321 can be safely administered and effectively mobilizes PBC in patients with bone marrow defects. PIXY321-mobilized PBC autotransplants result in rapid and sustained hematopoietic recovery.

Adult↗
PubMed1996

Activity of acetyl-n-ser-asp-lys-pro (AcSDKP) on hematopoietic progenitor cells in short-term and long-term murine bone marrow cultures.

The tetrapeptide AcSDKP is a potent inhibitor of hematopoietic stem cell proliferation. Its activity was systematically examined in murine long-term bone marrow cultures (LTBMC) and short-term liquid cultures in the presence or absence of exogenous cytokines. The effects of AcSDKP on the production of granulocyte-macrophage colony-forming cells (CFU-GM) and high proliferative potential colony-forming cells (HPP-CFC) in LTBMCs were examined. AcSDKP was added daily to LTBMCs at various concentrations (10-3--10-16M) for up to 5 weeks. AcSDKP inhibited the entry of progenitor cells into S phase as measured by 3H-thymidine suicide assay and the absolute number of progenitor cells with peak activity at 10-12 M with less activity seen at higher or lower concentrations. The number of nonadherent CFU-GM per LTBMC was unchanged from control values at 1 week of treatment with AcSDKP but was significantly depressed at weeks 3 and 5. In contrast, HPP-CFC progenitor cells were decreased throughout the treatment period, and the numbers of CFU-GM and HPP-CFC in S phase were significantly decreased throughout the treatment period. Maximum S-phase inhibitory activity was observed at 10-12 M AcSDKP. AcSDKP had no effect on the number of adherent CFU-GM or HPP-CFC, cellularity per culture or percent of adherent progenitor cells in S phase. Murine short-term bone marrow cultures were also treated with AcSDKP in the presence or absence of cytokines (interleukin-3 [LI-3], stem cell factor [SCF], or granulocyte colony-stimulating factor [G-CSF]) for various time periods. Dose-response studies showed maximum effects at 10-12 M AcSDKP when no cytokines were added and 10-14 M AcSDKP when exogenous cytokines were added. These studies indicate that the concentration of the tetrapeptide critical in obtaining an effect on hematopoietic progenitor cells, and furthermore, we report that the presence of cytokines or stromal cells also affects the response of progenitor cells to AcSDKP.

Amino Acid Sequence↗
PubMed1996

In vivo protective effects of tetrapeptide AcSDKP, with or without granulocyte colony-stimulation factor, on murine progenitor cells after sublethal irradiation.

Acetyl-N-Ser-Asp-Lys-Pro (AcSDKP) demonstrated hemato-protective activity in mice after sublethal irradiation (7 GY). Bone marrow interleukin-3 (IL-3)-responsive colony-forming cells (CFC and high proliferative potential colony-forming cells (HPP-CFC) were significantly (p < 0.05) increased by day 10 after irradiation in mice receiving a continuous infusion of 1000 ng/day of AcSDKP compared to irradiated control mice. The maximum protective effect for bone marrow progenitors was achieved when AcSDKP was administered for 3 days beginning 24 hours before irradiation. Other dosages and schedules in relationship to irradiation were less active. Further, when granulocyte colony-stimulating factor (G-CSF) was administered for 10 days beginning 24 hours before irradiation. Other dosages and schedules in relationship to irradiation were less active. Further, when granulocyte colony-stimulating factor (G-CSF) was administered for 10 days after AcSDKP infusion in irradiated mice, significantly increased numbers of IL-3 responsive CSF-only control mice. In addition, platelets were significantly (p < 0.05) increased in mice receiving AcSDKP and G-CSF on days 18 and 21 after irradiation compared with mice receiving G-CSF alone. We conclude that ACSDKP has a radioprotective effect in vivo for progenitor cells, and that time of initiation and duration of AcSDKP administration relative to irradiation are crucial for these effects. Further, AcSDKP has a significant additive protective effect not only for progenitor cells but also for platelets when given in combination with G-CSF. We suggest that these in vivo observations provide a basis on which to design optimal clinical hypothesis and protocols.

Amino Acid Sequence↗
PubMed1996

Immunologic attributes of cytokine mobilized peripheral blood stem cells and recovery following transplantation.

The immunologic attributes of cytokine mobilized peripheral blood stem cell (PSC) products (n = 52) and the resulting reconstitution of the hematopoietic and immunologic system following autologous transplantation were examined in a consecutive population of non-Hodgkin lymphoma (NHL), or solid tumor patients at the University of Nebraska Medical Center. Granulocyte-monocyte colony stimulating factor (GM-CSF)-mobilized PSC products had a high frequency of monocytes (31%) and bands (15%) as compared to normal peripheral blood (PB) cells. The phenotypic analysis of the mobilized PSC product revealed that they had normal levels of CD4+ cells, an increased frequency of CD8+ cells and a corresponding decrease in the CD4+:CD8+ cell ratio as compared to the peripheral blood leukocytes (PBL) of normal individuals. PSC products also had an increase in CD34+ cells as compared to PB. Natural killer (NK) and T cell activity in the PSC products were also lower than that observed in PB. Post-transplantation there was an accelerated reconstitution of NK-cell function in the PB as compared to T cell function (PHA (phytohemagglutinin) mitogenesis) which did not return to normal by day 100 post-transplantation. We also report for the first time high levels of an irradiation resistant suppressor cell activity in the PSC product and in the PB post-transplantation. There was also a concomitant increase in CD4-, CD8-, TCR alpha/beta+ cells (phenotypic homolog of 'natural suppressor' (NS) cells) in the PB post-transplantation. The number of months of prior chemotherapy correlated with PHA response but the NS activity and frequency of CD4-, CD8- and TCR alpha/beta+ cells did not. Further, cytokine mobilization and apheresis appears to contribute to the loss of PHA responsiveness and the increased levels of suppressor cell activity.

Antigens, CD34↗
PubMed1995

Interleukin-12 enhances peripheral hematopoiesis in vivo.

Interleukin 12(IL-12) is a cytokine that supports the proliferation and activation of cytotoxic T lymphocytes and natural killer (NK) cells. Recent evidence has suggested that IL-12 also has hematopoietic activities in vitro. We report studies that show that IL-12 has significant in vivo hematopoietic stimulating activity that includes enhancement of peripheral (splenic) hematopoiesis and mobilization of hematopoietic progenitor cells to the peripheral circulation. A single injection of recombinant murine IL-12 significantly reduced the number of bone marrow (BM) colony-forming unit granulocyte-macrophage (CFU-GM) in a time-dependent manner, while concomitantly stimulating high proliferative potential. In contrast, splenic CFU-GM and HPP were increased in a time- and dose-dependent manner. Chronic administration of IL-12 resulted in significant splenic hyperplasia with increased progenitor cells, increased circulating progenitor cells, and BM hypoplasia with decreased progenitor cells. These data show that IL-12 has significant in vivo hematopoietic effects that include the ability to mobilize progenitor cells to the peripheral circulation, which may prove to be of significant benefit for peripheral blood stem cell transplantation. Thus, IL-12 has potential to be an important agent for clinical transplantation because of its hematopoietic mobilization and its previously shown immune augmenting and therapeutic activities. This combination of hematopoietic and immune functions is unique and not achievable with currently used hematopoietic growth factors.

Animals↗
PubMed1995

Functional and phenotypic characterization of human peripheral blood stem cell harvests: a comparative analysis of cells from consecutive collections.

A considerable number of patients with malignancies who are treated with high-dose therapy and hematopoietic stem cell transplantation subsequently relapse. Analyses of peripheral blood stem cell (PBSC) harvests obtained from 49 cancer patients showed that the PBSC harvest contained precursors for antitumor effector cells. Ex vivo manipulation of these harvests to maximize the antitumor effector cell activity may provide a new therapeutic approach to decrease or eliminate any minimal residual disease that remains after high-dose therapy. Characterization of PBSC from consecutive collections determined the collections best suited for ex vivo augmentation of antitumor cytotoxic effector cells. We report the results of a functional and phenotypical characterization of PBSC obtained from six consecutive collections from 18 cancer patients receiving granulocyte-macrophage colony-stimulating factor (GM-CSF) for hematopoietic stem/progenitor cell mobilization. The PBSC were evaluated for their cytotoxicity using the 51Cr-release assay. The frequency and subsets of lymphocytes were determined using flow cytometry with appropriate specific marker antibodies and differential cell counts. The content of hematopoietic progenitor cells in each collection was determined using a colony-forming unit granulocyte-macrophage (CFU-GM) culture assay. The frequency of cytotoxic effector cells including lymphokine-activated killer (LAK) cell precursors and lymphocytes was significantly greater (P < .05) in the early collections, whereas the later collections contained significantly (P < .05) more CFU-GM progenitor cells and fewer cytotoxic effector cells. Thus, our results show that PBSC obtained from advanced cancer patients do contain considerable levels of precursor cells for the generation of LAK cell populations. These results suggest that cells from the earlier collections are best suited for ex vivo manipulation to augment the antitumor effects.

Adolescent↗
PubMed1995

Effects of BCR-ABL antisense oligonucleotides (AS-ODN) on human chronic myeloid leukemic cells: AS-ODN as effective purging agents.

We examined phosphorothioate oligodeoxyribonucleotides (ODNs) directed against bcr in exon 3 or exon 2, which are rearranged with exon 2 of abl (B3A2 and B2A2) at t(9;22) of chronic myelogenous leukemia (CML). Since these ODNs are designed to be CML cell specific, we studied their effects on the human CML cell line K562, which is known to have B3A2 rearrangement, and leukemic cells from patients, as well as normal hematopoietic stem cells in vitro. In vitro experiments were performed to determine a potential role of these two ODNs as ex vivo purging agents. Incubation of B3A2 antisense at 40, 80, and 120 micrograms/ml with K562 CML cells for 72 hours at 37 degrees C resulted in 44%, 56%, and 63% reduction of CFU-L as compared to controls. In contrast, B3A2 sense and B2A2 antisense had no significant growth inhibitory effect on K562 cells. Incubation of B3A2 and B2A2 antisense ODNs at concentration of 80 micrograms/ml at 37 degrees C for 36 hours with normal peripheral blood stem/progenitor cells (PBSC) resulted in 124% and 98% CFU-GM formation as compared to untreated controls, respectively. However, incubation of PBSC with B3A2 and B2A2 sense-ODNs resulted in a 22% and 44% reduction in CFU-GM, respectively. In order to determine the ex vivo purging effects of bcr-abl ODNs, the K562 cells were mixed with PBSC from normal donors at a ratio of 1:20 (CML:PBSC). The mixture of cells was then incubated with B3A2 antisense at 80 micrograms/ml for 36 hrs at 37 degrees C. After incubation, no CML cells were detected by fluorescence in situ hybridization (FISH) as compared to untreated controls. These results were confirmed by RT-PCR using bcr-abl primers and mRNA isolated from the mixture of cells. Further, these results support the hypothesis that bcr-abl antisense ODNs are potentially effective agents for ex vivo purging of autologous stem cells before transplantation to eliminate/reduce the burden of leukemic cells. No significant toxicity to normal hematopoietic stem/progenitor cell population by the bcr-abl antisense ODNs was observed. Although unanticipated reductions in normal hematopoietic progenitor cells (CFU-GM) were observed with sense ODNs, no reduction in CFU-GM was observed with unrelated phosphorothioate ODN controls.

Base Sequence↗
PubMed1995

Erythropoietin for mobilization of circulating progenitor cells in patients with previously treated relapsed malignancies.

A trial to determine the usefulness of recombinant human erythropoietin (rhEpo) as a mobilizing cytokine for patients with previously treated relapsed malignancies was performed. An initial peripheral stem cell apheresis collection was conducted during steady-state hematopoiesis for each patient to provide baseline data. rhEpo, 200 U/kg/day, was administered subcutaneously until the last apheresis procedure was completed. Immediately after the fourth daily dose of Epo, apheresis procedures were resumed and continued beyond five collections, when necessary, to accrue a total of 6.5 x 10(8) mononuclear cells (MNCs)/kg. Eight female and four male patients (median age = 44 years) were evaluated. Five to 14 (median = 8) apheresis procedures were performed for each patient. Toxicity attributable to Epo administration was negligible. Mobilization effects, as determined by an increase in the number of colony-forming units granulocyte/macrophage (CFU-GM) and burst-forming units-erythroid (BFU-E) in the apheresis products after Epo administration, were observed in all patients. Nine patients received high-dose chemotherapy and Epo-mobilized peripheral stem cell transplantation (PSCT). Beginning the day of the transplant, GM-CSF was administered until neutrophil recovery was satisfactory. The median time to recover 0.5 x 10(9)/L granulocytes was 16 days after PSCT. Epo appears to have mobilization properties. Further studies are needed to determine the clinical usefulness of Epo as a mobilizing cytokine. The addition of Epo to other mobilizing cytokines may provide increased effectiveness without adding toxicity.

Adult↗
PubMed1994

High-dose therapy and peripheral blood progenitor cell transplantation: effects of recombinant human granulocyte-macrophage colony-stimulating factor on the autograft.

Between June 1989 and June 1992, 144 patients participated in sequential clinical trials using peripheral blood progenitor cells (PBC) as their sole source of hematopoietic rescue following high-dose chemotherapy. All patients had received prior extensive combination chemotherapy and had marrow defects that precluded autologous bone marrow transplantation (ABMT). PBC were collected according to a single apheresis protocol. The initial 86 patients (group 1) had PBC collected without mobilization. Beginning in April 1991, PBC were mobilized solely with recombinant human granulocyte-macrophage colony-stimulating factor (rHuGM-CSF). Thirty-four patients (group 2) received rHuGM-CSF at a dose of 125 micrograms/m2/d by continuous intravenous infusion, and 24 patients (group 3) received rHuGM-CSF at a dose of 250 micrograms/m2/d by continuous intravenous infusion. Patients underwent at least six aphereses and had a minimum of 6.5 x 10(8) mononuclear cells (MNC)/kg collected. Cytokines were not routinely administered immediately after transplantation. A median of nine aphereses were required to collect PBC in group 1 and seven aphereses for groups 2 and 3 (P = .03). The time required to recover 0.5 x 10(9)/L granulocytes after transplant was significantly shorter (P = .0004) for the mobilized groups; the median time to recovery was 26 days for group 1, 23 days for group 2, and 18 days for group 3. Transplantation of PBC mobilized with rHuGM-CSF resulted in a shorter time to platelet (P = .04) and red blood cell (P = .01) transfusion independence. Mobilization with rHuGM-CSF alone resulted in efficient collection of PBC, that provided rapid and sustained restoration of hematopoietic function following high-dose chemotherapy. Mobilization of PBC with rHuGM-CSF alone is an effective method for patients who have received prior chemotherapy and have bone marrow abnormalities.

Adolescent↗