Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

One of the principal challenges of cancer chemotherapy is the relative inability of most anticancer drugs to distinguish between normal and neoplastic tissues. Consequently, a broad range of toxicities are experienced by patients, especially myelosuppression. Amifostine, a phosphorylated aminothiol, increases the selectivity of specific anticancer drugs for neoplastic cells by protecting normal tissues. One potential application of this protector is during bone marrow purging to selectively remove contaminating cancer cells. This study took normal or leukemic marrow from human subjects and evaluated the ability of amifostine to selectively protect normal bone marrow progenitor cells versus leukemic progenitor cells from the cytotoxic effect of mafosfamide. The dose response of mafosfamide amifostine on leukemia colony-forming units or normal marrow progenitor cells was determined and the LD95 was calculated. Amifostine pretreatment resulted in a statistically significant protection of granulocyte-macrophage colony-forming units and erythroid blast-forming units from the toxicity of mafosfamide (P = .031). Thus, amifostine protection of normal marrow progenitor cells allows a higher LD95 concentration of mafosfamide to be used in ex vivo purging. In contrast, amifostine pretreatment increased the cytotoxicity of mafosfamide on the fresh human leukemia progenitor cells (P = .006). The dual effect of amifostine protection of normal marrow progenitor cells coupled with amifostine-induced sensitization of the leukemia cells increases the possible cell-kill of leukemic stem cells. With amifostine pretreatment, at the LD95 concentrations of mafosfamide for marrow progenitor cells, there was an estimated 6 log increase in cell-kill of the leukemia cells. This selective cell-kill offers the potential for lowering the incidence of leukemic relapse, while preserving more normal stem cells for autologous transplantation.
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PMID:Amifostine improves the antileukemic therapeutic index of mafosfamide: implications for bone marrow purging. 767 Jan 19

Autologous bone marrow transplantation (ABMT) has considerably developed in the past 20 years. In AML, the beneficial role of purging the graft with cyclophosphamide derivatives (4-HC or mafosfamide) has been strongly suggested by retrospective studies from the European Cooperative Group for Blood and Marrow Transplantation and by single institution studies. Also, gene marking experiments have clearly shown that tumour cells infused with unpurged marrow indeed recirculate and in some instances, induce or contribute to tumour recurrence. Amifostine protects normal progenitor cells without concomitantly protecting colony forming unit leukaemic progenitors (CFUL). In comparative in vitro studies, we have shown that pre-incubation of normal marrow contaminated by leukaemic progenitors with amifostine followed by mafosfamide, results not only in a protection of the more mature progenitors (CFUGM, BFUE), but also sensitises leukaemic progenitors, so that in the end, the therapeutic index of mafosfamide is increasing by 6 logarithms. In the clinical field, it has been shown in patients with breast cancer autografted with protection by amifostine results in a shortening of the duration of aplasia of about 10 days. A European randomised study evaluating amifostine in the context of autografting for acute leukaemia has just started.
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PMID:The potential role of amifostine (Ethyol) in haematological malignancies. 897 20

Amifostine (WR-2721, Ethyol) is a phosphorylated aminothiol that affords broad cytoprotection from the myelosuppressive effects of antineoplastics. To further characterize its hematopoietic activities, we investigated the effects of amifostine and its dephosphorylated metabolite, WR1065, on the in vitro growth of human bone marrow progenitors. Preincubation exposure to amifostine or WR1065 stimulated the growth of colony-forming units granulocyte, erythroid, macrophage, megakaryocyte (CFU-GEMM) and erythroid bursts (BFU-E) from bone marrow mononuclear cells in a dose-dependent fashion. Over the concentration range tested (0.1-1000 microM), pretreatment with the aminothiols enhanced formation of CFU-GEMM up to five-fold and BFU-E nine-fold, compared to a three-fold increase in myeloid colony recovery. In CD34+ selected cells, preincubation with amifostine increased formation of CFU-GEMM up to 38-fold and produced macroscopic colonies, exceeding colony number in cultures initiated with optimal concentrations of interleukin-1 (IL-1), IL-3, or kit ligand (KL). When compared with recombinant human cytokines, amifostine enhanced IL-1 and IL-3 induced colony formation, although its stimulatory effect was less than additive. In contrast, pretreatment with amifostine antagonized the stimulatory effects of KL, whereas synergy was observed with concurrent exposure. Ex vivo expansion studies showed that amifostine alone supported and augmented the production of myeloid progenitors in secondary cultures. Similarly, under cytokine-deficient conditions, amifostine promoted cell survival and delayed apoptosis as measured by nucleosome generation. These data indicate that amifostine is a novel multipotent hematopoietic stimulant that augments the formation and survival of bone marrow progenitors.
Leukemia 1998 Oct
PMID:Amifostine stimulates formation of multipotent and erythroid bone marrow progenitors. 976 5

Amifostine (Ethyol) is an analog of cysteamine that selectively protects normal tissues in multiple organ systems against the toxic effects of radiation and various cytotoxic drugs while preserving the antitumor effects of these therapies. Amifostine was evaluated in a multicenter, multinational phase III clinical trial that enrolled women with stage III/IV ovarian cancer. Its effects have also been studied using normal human bone marrow and human breast cancer cells, as well as leukemia cells. Additional clinical trials have shown that amifostine can protect normal tissues from the toxic effects of alkylating agents, organoplatinums, anthracyclines, taxanes, and radiation. Other laboratory and clinical investigations indicate a potential role for this cytoprotective agent in the treatment of the ineffective hematopoiesis characteristic of the myelodysplastic syndromes.
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PMID:Clinical status and optimal use of amifostine. 1002 98

The phosphorylated thiol amine, amifostine (Ethyol; Alza Pharmaceuticals, Palo Alto, CA/US Bioscience, West Conshohocken, PA), is a cytoprotective agent for cisplatin-based chemotherapy. Recent investigations have given rise to new potential applications of amifostine in hematologic malignancies. Amifostine appears to exert a sustained mitogenic effect in primitive hematopoietic progenitors that results in a significant increase in colony-forming capacity. Amifostine also retards cell loss and delays commitment to apoptosis initiated by cytokine deprivation, suggesting that amifostine has trophic effects similar to the hematopoietic cytokines. The abilities to prolong progenitor survival and to delay apoptosis under conditions of cellular stress make amifostine an attractive agent for investigation in bone marrow failure states. Amifostine promotes more effective hematopoiesis in patients with myelodysplastic syndrome, although additional investigation is needed to further define the optimal dose and schedule of administration. Furthermore, amifostine may selectively enhance the cytotoxicity of chemotherapeutic agents in leukemia progenitors. When the sensitivity of leukemic and normal progenitors to mafosfamide was evaluated with and without amifostine pretreatment, amifostine effectively protected normal myeloid and erythroid progenitors while increasing leukemic cell kill. Thus, amifostine represents a unique agent with promising potential for therapeutic application in hematologic malignancies. Further investigation is needed to define its role in clinical practice.
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PMID:Use of amifostine in hematologic malignancies, myelodysplastic syndrome, and acute leukemia. 1034 62

The in vivo effect of the radiochemoprotectant Amifostine on the therapeutic efficacy of marrow ablative treatment with cyclophosphamide (CP) and total body irradiation (TBI) followed by bone marrow transplantation (BMT) was studied in normal rats as well as in the Brown Norway rat acute myelocytic leukaemia (BNML) model. In normal rats, when the dose of TBI was escalated and the CP dose was kept constant, pretreatment with Amifostine yielded a positive dose modification factor of 1.26. No significant improvement was found after Amifostine pretreatment when the TBI dose was kept constant and CP dose escalated. When leukaemic rats received CP as the only antileukaemia treatment, Amifostine pretreatment did not lead to a reduction in the antileukaemic efficacy of CP, although protection against treatment-related mortality was observed. In the CP only groups, 9 out of 40 animals died of treatment-related toxicity, compared with none of the 40 animals in the Amifostine pretreatment groups. When applying the maximum tolerated treatment of CP and TBI in various combinations to leukaemic rats, 25 out of 36 rats died from treatment-related toxicity, whilst pretreatment with Amifostine reduced this to 11 out of 36, (P = 0.002). Of those animals which survived the CP + TBI conditioning treatment, 10 out of 25 in the Amifostine pretreatment group were cured, versus 8/11 in the CP + TBI only control group (P = 0.146). In conclusion, incorporation of Amifostine as a radiochemoprotectant in a marrow-ablative conditioning regimen allows the use of escalated doses of chemoradiotherapy without reducing the antileukaemic efficacy.
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PMID:Amifostine (WR2721) for dose escalation in marrow-ablative treatment of leukaemia. 1049 39

Ex vivo pharmacological purging of bone marrow has been used to eliminate clonogenic tumor cells contaminating the autograft and potentially responsible of relapse. A considerable improvement of pharmacological purging would be achieved only if normal marrow progenitor cells could be selectively protected by the cytotoxicity of these agents. Amifostine (WR-2721; Ethyol), a phosphorylated aminothiol compound, has been shown to have this property both in vivo and in vitro. We describe here, an experimental model for ex vivo purging of peripheral blood progenitor cell (PBPC) collections based on the combination of 3 mg/ml of amifostine and the alkylating agent nitrogen mustard. Amifostine pretreatment resulted in a statistically significant protection of normal late and early progenitor cells. Under the same experimental conditions, we observed a 4-6 log reduction of contaminating leukemic cells (i.e., K-562 and CEM) and in contrast to the protection of normal peripheral blood progenitor cells, preincubation of contaminating K-562 or CEM with amifostine did not significantly alter the LD95 nitrogen mustard concentration. Moreover, when we tested fresh human leukemia progenitor cells, amifostine pretreatment sensitized the leukemic cells to the cytotoxic effects of NM.
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PMID:Ex vivo pharmacological purging of leukapheresis collections with nitrogen mustard: amifostine pretreatment improves both early and late peripheral blood progenitor cell recovery. 1051 97

Myelosuppression is one of the most common side effects during chemotherapy in children with leukemia and lymphoma. That is why the protection of patients against the acute and chronic toxicity of antineoplastic therapy has become a major concern of oncology centers. Amifostine (Ethyol--Schering-Plough) represents a new adjunct for the management of cancer patients receiving chemotherapy. It has the ability to protect selectively a range of tissues and bone marrow against acute and cumulative toxicity of chemotherapy. Because solid tumors tend to be hypovascular and more acid than normal tissue, amifostine may protect selectively normal tissue. Amifostine is believed to scavenge free radicals, repair radicals on essential molecules and from mixed disulfides to protect normal cells. In this trial we demonstrate how amifostine protects granulocytes, erythrocytes and platelets against toxicity of chemotherapy.
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PMID:[Amifostine (ethyol) in the adjunctive treatment of children with acute lymphoblastic leukemia]. 1073 70

Twenty patients with poor prognosis AML and four patients in the blastic phase of a myeloproliferative disorder were treated with two 'pulses' of therapy each consisting of two doses of high dose araC (separated by 12 h) followed by a single dose of mitoxantrone. The pulses were separated by 96 h. Amifostine was then administered tiw. The median age of the population was 68 years with 88% of patients having had either a prior MDS, MPD or toxic exposure. The acute leukemia of 58% of patients either entered a CR or reverted to preleukemic state. For patients under 70 years of age, treatment produced 62% CRs with a leukemia free decision marrow in 77%. For patients over 70 years the CR rate was 27% with 36% of patients having a leukemia free decision marrow.
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PMID:Poor prognosis acute myelogenous leukemia: 1 - response to treatment with high dose cytarabine/mitoxantrone/ethyol @ (Amifostine). 1093 21

Amifostine (WR-2721) is an aminothiol compound dephosphorylated at the tissue site by alkaline phosphatase to the active metabolite, which is able to inactivate electrophilic substances and scavenge free radicals. Amifostine effects against melphalan-induced DNA strand breaks were studied in normal human white blood cells (WBC) and K562 leukemic cells using the single cell gel electrophoresis (SCGE) or Comet assay, a reported method for measuring DNA damage in individual cells. Prior to treatment (1 h, 37 degrees C) with increasing doses of melphalan, with or without S9, the cells were treated (15 min, 37 degrees C) with a control medium or amifostine (3 mg/ml). Treatment of normal and leukemic cells with melphalan induced a dose-dependent 'comet formation'. Melphalan-induced DNA damage follows a normal distribution in WBC. On the other hand, in K562, a significant proportion of undamaged cells remains even with doses at which mean DNA damage is serious. Pretreatment with WR-2721 protects WBC, but not K562, against the genotoxic effect of melphalan. Amifostine might even strengthen the action of the antiblastic drug against K562 cells. S9 addition appears to enhance melphalan effectiveness. SCGE appears as a suitable primary screening method for in vitro and in vivo studies on drug-DNA interactions and their modulations by endogenous/exogenous factors.
Leukemia 2000 Sep
PMID:Amifostine (WR-2721) selective protection against melphalan genotoxicity. 1099 12


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