Ex vivo pharmacological purging of leukapheresis collections with nitrogen mustard: amifostine pretreatment improves both early and late peripheral blood progenitor cell recovery

A novel mode of stimulating platelet formation activity in megakaryocytes with peanut skin extract

We report in this study novel biochemical activities of peanut skin extract (PEXT) on thrombocytopoiesis. Peanut skin, derived from Arachis hypogaea L., is a traditional Chinese medicine that is used to treat chronic hemorrhage. We have shown that oral administration of PEXT increases the peripheral platelet levels in mice. Recently, we reported a liquid culture system that is useful for investigating megakaryocytopoiesis and thrombocytopoiesis from human CD34⁺ cells. In this liquid culture system, PEXT was shown to enhance the formation of CD41⁺/DAPI^- cells (platelets), but had no effect on the formation of CD41⁺/DAPI⁺ cells (megakaryocytes) or on the DNA content. Furthermore, PEXT selectively stimulated proplatelet formation from cultured mature megakaryocytes and phorbol 12-myristate 13 acetate (PMA)-induced formation of platelet-like particles from Meg01 cells. Despite having no influence on the formation of megakaryocyte colony forming units (CFUs), PEXT increased the size of megakaryocytes during their development from CD34⁺ cells. PEXT showed no effect on the GATA-1 and NF-E2 mRNA levels, which are known to play an important role in thrombocytopoiesis and, based on the results of a pMARE-Luc (pGL3-MARE-luciferase) assay, had no influence on NF-E2 activation in Meg01 cells. These results suggest that PEXT accelerates proplatelet formation from megakaryocytes but does not influence the development of hematopoietic stem cells into megakaryocytes.

A new intensive induction schedule, including high-dose Idarubicin, high-dose Aracytin and Amifostine, in older AML patients: feasibility and long-term results in 42 patients

OBJECTIVE

We evaluated the feasibility of a new regimen in elderly patients with acute myeloid leukemia (AML). The main end points were overall response rate (ORR) and toxicity; secondary end points were feasibility of peripheral blood stem cells (PBSC) collection, leukemia-free survival, and overall survival (OS).

PATIENTS AND METHODS

We treated 42 fit elderly patients with high-dose (HD) idarubicin plus HD-cytarabine (Ara-C), with amifostine.

RESULTS

We observed one treatment-related death (2%). The main extrahematological toxicity was represented by grade III to IV infections in 64% of patients. Hematological toxicity was acceptable with 15 days (range, 9-29 days) to reach >500 x 10(6)/L absolute neutrophil count and 16 days (range, 3-39 days) to achieve an unsupported platelet count >20,000 x 10(6)/L. Median duration of severe neutropenia was 12 days (range, 1-36) and median number of febrile days and intravenous antibiotics therapy was 6 (range, 0-17) and 17 days (range, 0-34), respectively, Median duration of hospitalization was 31 days (range, 20-61). ORR was 83% (34 of 41); 32 patients received intensive consolidation therapy; 15 patients were able to mobilize a sufficient number of CD34+ cells; and 14 were transplanted.

CONCLUSION

According to the intention to treat criteria all patients were analyzed for outcomes. Five-year OS was 19%, with median follow-up of 38 months. Patients with unfavorable cytogenetic and those with secondary AML had poorer OS; about 40% of patients could mobilize a sufficient amount of PBSC for autologous stem cell transplantation.

Role of stem cells in cancer therapy and cancer stem cells: a review

For over 30 years, stem cells have been used in the replenishment of blood and immune systems damaged by the cancer cells or during treatment of cancer by chemotherapy or radiotherapy. Apart from their use in the immuno-reconstitution, the stem cells have been reported to contribute in the tissue regeneration and as delivery vehicles in the cancer treatments. The recent concept of 'cancer stem cells' has directed scientific communities towards a different wide new area of research field and possible potential future treatment modalities for the cancer. Aim of this review is primarily focus on the recent developments in the use of the stem cells in the cancer treatments, then to discuss the cancer stem cells, now considered as backbone in the development of the cancer; and their role in carcinogenesis and their implications in the development of possible new cancer treatment options in future.

Additive apoptotic effect of STI571 with the cytoprotective agent amifostine in K-562 cell line

PURPOSE

To study the apoptotic effect of the 2-phenylaminopyrimidine derivative STI571 in combination with antioxidant agents on K-562 cell line derived from a Philadelphia chromosome-positive chronic myeloid leukemia patient.

MATERIALS AND METHODS

K-562 (BCR/ABL+), U-937, and HL60 (BCR/ABL-) leukemic cell lines were incubated with STI571 and the antioxidant agents catalase, glutathione, superoxide dismutase, and amifostine (AMI). Apoptotic effect was analyzed by morphological and flow cytometric criteria.

RESULTS

STI571 at concentrations higher than 0.25 mumol L(-1) produced apoptosis (P<0.05) in K-562 cells only after treatment for 72 h. At the mentioned concentrations, STI571 also induced an increase in the loss of mitochondrial transmembrane potential from 24.6 to 40%. Combination of STI571 (0.5 micromol L(-1)) with antioxidant agents showed that the cytoprotective agent AMI (0.75 mg mL(-1)) produced an additive effect in the proapoptotic activity of STI571 in K-562 cells at nuclear (58.8%+/-2.0 vs. 28.9%+/-3.3) and mitochondrial (53.3%+/-3.6 vs. 29.5%+/-1.2) levels.

CONCLUSIONS

Our results show that only AMI in combination with STI571, at submicromolar concentration, has an additive effect in K-562 cell line, and it does not have severe toxic effects on Philadelphia chromosome negative cells.

A randomized trial of amifostine as a cytoprotectant for patients receiving myeloablative therapy for allogeneic hematopoietic stem cell transplantation

We initiated a randomized study of amifostine (the organic thiophosphate formerly known as WR-2721) given to patients during myeloablative conditioning therapy for allogeneic bone marrow transplantation. Amifostine was given at a dose of 1000 mg/day of conditioning and was well tolerated if attention was given to serum calcium levels, blood pressure and antiemetics. Since August 1998, 60 patients (30 on each arm) have completed the study. There was no significant difference in the days to neutrophil or platelet engraftment in either arm of the study. Significantly, the duration of grade I-IV mucositis was decreased in the group that received amifostine (P=0.02). Also grade III or IV infections (P=0.008), duration of antibiotic therapy (P=0.03) and duration of fever (P=0.04) were significantly reduced with amifostine. However, there were no differences in the incidence of grade III or IV mucositis, liver toxicity or renal toxicity. There were also no differences in early mortality, relapse and long-term survival. We conclude that amifostine, while reducing the duration of mucositis and infections (possibly through some preservation of gut mucosal integrity), has a modest effect in allogeneic bone marrow transplants given the multiplicity of factors influencing organ toxicity and survival in this setting.

Sensitivity of myeloid leukemia cells to calcium influx blockade: application to bone marrow purging

OBJECTIVE

The aim of this study was to assess the potential of store-operated Ca(2+) channel (SOC) antagonists as purging agents for leukemia cells.

MATERIALS AND METHODS

Clonogenic, limiting dilution, and nuclear condensation assays were used to evaluate SOC antagonist efficacy. SOC activity and endoplasmic reticulum Ca(2+) content were measured by flow cytometry. Murine bone marrow transplantation was used to determine purging efficacy and effects on hemopoietic reconstitution.

RESULTS

Econazole (Ec) and ketotifen (Ke) were variably effective against human and murine leukemia cell lines after 24 hours of incubation. However, a 2-hour serum and bovine serum albumin-free treatment protocol with Ec was found to maximize differential sensitivity between leukemic cells and normal hemopoietic progenitors. Primary acute myelogenous leukemia blast cell viability was reduced 4.2 to 5.1 logs by 2-hour Ec treatment as measured by limiting dilution. An inverse relationship between endoplasmic reticulum Ca(2+) content and Ke sensitivity in leukemia and untransformed cells was observed. Nuclear condensation, an index of apoptosis, which occurred after 24-hour treatments with either Ec or Ke, was not observed after 2-hour serum- and bovine serum albumin-free Ec exposures; however, condensed nuclei were observed after an additional 10-hour incubation in growth medium without drug. Using bone marrow deliberately contaminated with 1% P815 cells, we showed that highly effective in vitro purging can be accomplished using Ec with no adverse effects on bone marrow reconstitution in mice.

CONCLUSIONS

These studies suggest that SOC antagonists have potential as purging agents for residual leukemia cells present in bone marrow in the context of high-dose chemotherapy and autologous transplantation for leukemia.

Acute myeloblastic leukemia achieving complete remission with amifostine alone

Amifostine, a phosphorylated thiol-amine, is known as a cytoprotective agent especially for cisplatin containing chemotherapies. Apart from the cytoprotective role, Amifostine could also be used in the treatment of hematologic malignancies such as myelodysplastic syndrome (MDS) and acute myeloblastic leukemia (AML), as a treatment option or for potentiating the effects of cytotoxic agents. We tried to use Amifostine in a patient with AML, which did not respond to conventional cytotoxic chemotherapy and aimed to publish the results. The patient was a 77-year-old male patient, he was diagnosed as AML by peripheral blood smear and bone marrow aspiration. Treatment commenced with low dose cytosine arabinoside (Ara-C) but the therapy should have ceased due to patient intolerance. The patient refused further therapy and he was offered to have Amifostine treatment. Amifostine was administered 200 mg/m2 three times a week, with ciprofloxacin, pentoxifyllin and dexamethasone. Dramatic response was obtained after 8 weeks of administration. Blast rate was reduced from 35 to 7% in bone marrow aspiration; pancytopenia was restored to normal levels. This remission was maintained through 8 more weeks. Amifostine treatment was restarted after he relapsed but this time he did not respond to the treatment and died of gastrointestinal bleeding on the 8th week of treatment.

A randomized phase II study of amifostine used as stem cell protectant in non-hodgkin lymphoma patients receiving cisplatin-based salvage chemotherapy prior to stem cell transplant

Stem cell mobilization may be inadequate in many lymphoma patients in need for autologous stem cell transplant (SCT). In this study, we sought to evaluate a potential role of amifostine as a stem cell chemoprotective agent in lymphoma patients receiving DHAP chemotherapy in preparation for high-dose chemotherapy (HDC) and stem cell transplant (SCT). In the beginning of the DHAP course, patients were randomized 1:1 to receive amifostine at 740 mg/m(2). Stem cells were mobilized with GCSF after the last cycle of DHAP. Stem cell collection started upon ANC recovery over 1000/mm(3). Standard 10 lt. apheresis daily with a goal of a minimum of 2 x 10(6) stem cells/kg were performed. Twenty-one patients have been enrolled; 10 received amifostine pretreatment (age, 20-64) and 11 were randomized to the control arm (age, 18-63). Prior chemotherapy was balanced in the two groups. The median number of DHAP treatments for each group was 2. Amifostine was well tolerated and was associated with higher stem cell collection. Toxicity and time to engraftment were comparable between the two groups. Our preliminary results may suggest a role of amifostine in protecting stem cells during salvage chemotherapy, thus facilitating stem cell collection.

Treatment of patients with myelodysplastic syndrome with amifostine

The efficacy and toxicity of amifostine (300 mg/m(2) three times a week for three consecutive weeks for a maximum of six courses) was evaluated in 12 patients with primary myelodysplastic syndromes. Dose escalation up to 400 mg/m(2) was allowed to patients who failed to respond. Hemoglobin concentration was increased > or = 1.5 g/dl in two (18%) of the 11 anemic patients. These two patients obtained transfusion independence for 20 weeks. Reticulocyte counts and ANC increased > or = 50% of baseline in four (44%) of the nine patients with reticulocytopenia and in three (25%) of the 12 neutropenic patients. Platelet count increased in three (50%) of the six patients with thrombocytopenia. Progenitor growth of CFU-GMs and BFU-Es improved in 8/12 patients. No major side effects were observed. In conclusion amifostine is well tolerated and can promote the growth of primitive hematopoietic progenitors and ameliorate the cytopenias in MDS patients.

Bone marrow stem cell protection from chemotherapy by low--molecular-weight compounds

The stem cells of the bone marrow have the capacity for both self-renewal and derivation of all the blood cell lineages. Consequently, toxicity to these cells can result in neutropenia, agranulocytosis, thrombocytopenia, pancytopenia, or aplastic anemia. Many anticancer drugs adversely affect the bone marrow, and neutropenia is a common limiting factor in dose escalation. In this review, we discuss agents that appear to have potential as bone marrow sparing agents. Computerized catalogs of the National Library of Medicine and Medline were searched for reports on low-molecular-weight compounds that detailed effects on the hematopoietic progenitor cells. The most promising agents are the endogenous peptides p-glutamic acid-glutamic acid-aspartic acid-cysteine-lysine and acetyl-serine-aspartic acid-lysine-proline, and the exogenous compounds amifostine and ammonium trichloro[dioxoethylene-O,O']tellurate, but several others are also discussed. These compounds preserve stem cell function in the presence of antineoplastic drugs of diverse pharmacological classes, and they do so by various mechanisms of action. Their present status in clinical practice is also detailed. More needs to be learned about their mechanisms of action and therapeutic potential, but the results are encouraging for some of these compounds and more clinical trials should be expected.

Amifostine can reduce mucosal damage after high-dose melphalan conditioning for peripheral blood progenitor cellautotransplant: a retrospective study

Amifostine (WR-2721; Ethyol) is a well-known cytoprotector, but a possible role in preventing extrahaematological toxicity after high-dose therapy (HDT) has never been investigated. We compared two historical groups of patients who either received (group A, n = 35) or did not receive (group B, n = 33) amifostine (740 mg/m2) before high-dose (HD) melphalan, followed by autologous infusion of peripheral blood progenitor cells (PBPCs). Amifostine was well tolerated at this dose level. Emesis grade 1-2 was the most important side-effect, but the interruption of infusion was never required. The incidence and median duration of severe mucositis (grade 3-4) was 21% and 0 d (range 0-11 d) in group A and 53% and 7 d (range 0-11 d) in group B. The duration of analgesic therapy was also significantly lower in group A (0 d; range 0-12) than in group B (6 d, range 0-20) (P = 0.0001). Severe diarrhoea (3% vs. 25%; P = 0.01) and emesis (9% vs. 34%; P = 0.01) were also reduced in group A in comparison with group B. No differences were observed between the two groups for haematological recovery. This retrospective study strongly suggests that amifostine can reduce severe mucositis and the use of analgesic drugs in this setting. A randomized study is warranted to confirm these preliminary results.