Evidence for a Role of TNF-Related Apoptosis-Inducing Ligand (TRAIL) in the Anemia of Myelodysplastic Syndromes (original) (raw)
Related papers
Leukemia Research, 1996
Extensive apoptosis or programmed cell death (PCD) of both hematopoietic (erythroid, myeloid, megakaryocytic) and stromal cells in myelodysplastic syndromes (MDS) cancels the high birth-rate resulting in ineffective hematopoiesis and has been demonstrated as the probable basis for peripheral cytopenias in MDS by our group. It is proposed that factors present in the microenvironment are inducing apoptosis in all the cells whether stromal or parenchymal. To investigate this hypothesis further, bone marrow biopsies from 46 MDS patients and eight normal individuals were examined for the presence of three cytokines, tumor necrosis factor-alpha (TNF-α), transforming growth factor-beta (TGF-β) and granulocyte macrophage-colony stimulating factor (GM-CSF) and one cellular component, macrophages, by the use of monoclonal antibodies immunohistochemically. Results showed the presence of TNF-α and TGF-β in and cases of MDS respectively, while only 15 cases showed the presence of GM-CSF. Further a significant direct relationship was found between the degree of TNF-α and the incidence of PCD (p = 0.0015). Patients who showed high PCD also had an elevated TNF-α level. Thus, the expression of high amounts of TNF-α and TGF-β and low amounts of the viability factor GM-CSF may be responsible for the high incidence of PCD leading to ineffective hematopoiesis in MDS. Future studies will be directed at attempting to reverse the lesion in MDS by using anti-TNF-α drugs such as pentoxifylline.
Erythropoiesis results from the proliferation and differentiation of pluripotent stem cells into immature erythroid progenitors (ie, erythroid burst-forming units (BFU-Es), whose growth, survival, and terminal differentiation depends on erythropoietin (Epo). Ineffective erythropoiesis is a common feature of myelodysplastic syndromes (MDS). We used a 2-step liquidculture procedure to study erythropoiesis in MDS. CD34 ؉ cells from the marrow of patients with MDS were cultured for 10 days in serum-containing medium with Epo, stem cell factor, insulinlike growth factor 1, and steroid hormones until they reached the proerythroblast stage. The cells were then placed in medium contain-ing Epo and insulin for terminal erythroid differentiation. Numbers of both MDS and normal control cells increased 10 3 fold by day 15. However, in semisolid culture, cells from patients with refractory anemia (RA) with ringed sideroblasts and RA or RA with excess of blasts produced significantly fewer BFU-Es than cells from controls. Fluorescence in situ hybridization analysis of interphase nuclei from patients with chromosomal defects indicated that abnormal clones were expanded in vitro. Epo-signaling pathways (STAT5, Akt, and ERK 1/2) were normally activated in MDS erythroid progenitors. In contrast, apoptosis was significantly increased in MDS cells once they differenti-ated, whereas it remained low in normal cells. Fas was overexpressed on freshly isolated MDS CD34 ؉ cells and on MDS erythroid cells throughout the culture. Apoptosis coincided with overproduction of Fas ligand during the differentiation stage and was inhibited by Fas-Fc chimeric protein. Thus, MDS CD34 ؉ -derived erythroid progenitors proliferated normally in our 2-step liquid culture with Epo but underwent abnormal Fas-dependent apoptosis during differentiation that could be responsible for the impaired erythropoiesis. (Blood. 2002;99:1594-1601)
Experimental Hematology, 2000
Objectives. To determine the relation of apoptosis and clonal proliferation in the bone marrow (BM) to the effectiveness of a therapeutic protocol described to downmodulate monokine activity in patients with myelodysplastic syndromes (MDS). Materials and Methods. Prior to protocol therapy, BM stroma was cultivated and selected CD34 ϩ cells were studied in stroma and cytokine-dependent clonogenic assays. The TUNEL assay was used to establish the degree of apoptosis occurring in the marrow and CD34 ϩ population. The effectiveness of oral ciproloxacin 500 mg b.i.d., pentoxifylline 800 mg t.i.d., and dexamathasone 4 mg t.i.d. (CPD) antiinflammatory therapy was correlated with the intensity of cell apoptosis and proliferation of BM progenitor cells. Results. Seventeen patients were studied. Twelve patients (10 transfusion dependent) received therapy for a median of 99 days (range 49-284). Toxicity caused four patients to discontinue the drug combination. Six patients fulfilled response criteria. Four patients became transfusion independent, and 50% reduction in the need for blood transfusions was noted in one patient. Blood parameters of one untransfused patient increased by Ͼ 30%. Blood count remained unsupported in three patients, even at a median of 12 months after trial discontinuation. Apoptosis of marrow cells and selected CD34 ϩ progenitors was detected in a median of 49.5% (range 3.6%-90%) and 10.6% (range 3.6%-100%; p Ͻ 0.01), respectively. In patients who responded to therapy, the median apoptosis rate in the bone marrow population was 71%, in contrast to the nonresponder's rate of 13% (p ϭ 0.002). Overall clonogenic growth of selected precursors corresponded significantly with response to CPD protocol (p ϭ 0.004). Conclusions. In some patients with MDS, ineffective hematopoiesis is related to high apoptotic index despite proliferation of the CD34 ϩ precursors. These patients seem to benefit from CPD cytokine modulatory therapeutic strategy.
Leukemia Research, 1993
By staining human bone marrow cells with a monoclonal antibody reacting with erythroid precursor cells (AS-E1) and propidium iodide, we have evaluated the proliferative capacity of erythropoiesis in patients with myelodysplastic syndromes (MDS) using flow cytometry. Comparing 36 patients (13 RA/RAS, 13 RAEB, 10 RAEB-t) with 7 normal controls, significant differences in both the percentage of AS-E1+ cells and the fraction of AS-E1+ cells in the S or S-G2M-phase between the four groups were found. Since neither the percentage of AS-E1+ cells nor their fraction in S or S-G2M alone was found to characterize their proliferative activity, we introduced the proliferative fractions of the erythroid cell, i.e. the number of the AS-E1+ cells in S or S-G2M related to all bone marrow cells in S or S-G2M. Applying these parameters, we found significantly increased proliferative AS-E1 fractions in the RA/RAS group compared to the normal controls (p = 0.03 rmand 0.002) respectively, as well as a highly significant decrease with disease progression.
Leukemia, 1997
By application of morphological and ultrastructural methods nosis. The pathogenesis of MDS is still unclear. It has been for identification of apoptosis, we analyzed the incidence of found that oncogene dysregulation is the basis of the disease. morphologically evident apoptosis in the bone marrow of 30 The paradox of persistent pancytopenia in peripheral blood patients with myelodysplastic syndrome (MDS), and in the with hypercellular bone marrow in most cases of MDS is bone marrow of 12 healthy individuals. According to FAB explained by the term 'ineffective hematopoiesis' but the real classification, out of 30 patients, eight (26.6%) had refractory anemia, three (10%) had refractory anemia with ringed sidero-mechanism responsible has not been explained yet. It has blasts, 14 (46.6%) had refractory anemia with excess of blasts been hypothesized that the mechanism of apoptosis may be and two (6.8%) had refractory anemia with excess of blasts in responsible for the ineffective hematopoiesis in MDS. 4 transformation. Three patients (10%) had chronic myelomono-In this study we analyzed bone marrow samples of 30 cytic leukemia. Cells in apoptosis were examined on semithin patients with MDS in order to evaluate the incidence of slides and expressed as the apoptotic index (AI) (percent counpremature apoptosis, as the morphological equivalent of 'inefted on at least 1000 cells). An overall increase in apoptosis in patients with MDS was found (median AI in patients vs controls, fective hematopoiesis'. 3.13% vs 1.05%, P Ͻ 0.01 by Mann-Whitney U test). Also, negative correlation between AI and white blood cell count was found (linear r = −0.53, or Spearman rank R = −0.52, both Patients and methods P Ͻ 0.01). In patients with evident karyotype changes AI was not higher than in patients with normal karyotype. This sug-Our study included 30 patients with primary MDS stratified gests that discrete alterations in apoptosis are present even in karyotypically 'normal' clones. Our results strongly support the according to criteria of FAB classification. 5 Out of 30 patients, hypothesis that apoptosis has a role in ineffective hematopoeight (26.6%) patients had refractory anemia (RA), three (10%) iesis and may be a mechanism responsible for the paradox of had refractory anemia with ringed sideroblasts (RARS), 14 hypercellular bone marrow and peripheral blood pancytopenia (46.6%) had refractory anemia with excess of blasts (RAEB) in MDS.
British Journal of Haematology, 2000
Treatment with recombinant human erythropoietin (rhEPO) improves anaemia in < 20% of the patients with myelodysplastic syndromes (MDS). Recent reports suggest that a combination treatment with rhEPO plus recombinant human granulocyte colony-stimulating factor (rhG-CSF) given for up to 18 weeks may result in a higher erythroid response rate than with rhEPO alone. We investigated the potential advantage of an even more prolonged schedule of combined rhG-CSF and rhEPO treatment to obtain and maintain stable responses. In a phase II study, 33 patients with MDS [17 with refractory anaemia (RA), eight with RA with ringed sideroblasts (RARS), eight with RA with excess blasts (RAEB) with bone marrow blast counts less than 20%] were scheduled to receive at least 36 weeks of combined therapy with rhG-CSF and rhEPO. Seventeen of 28 evaluable patients demonstrated an erythroid response [61%; 95% confidence interval (CI) 41±78] after 12 weeks of treatment. The erythroid response rate was 80% (20 of 25 evaluable patients; 95% CI 59±93) after 36 weeks. Seven of these responses developed between week 12 and week 36, whereas two initially responding patients became refractory. The cytokine therapy was generally well tolerated. Nineteen of the 20 patients responding after 36 weeks continued to be treated with both cytokines. After 1 year and 2 years of continuous combined treatment, 50% of the initially included patients showed a continuing response. Our results suggest that a prolonged combination treatment with rhG-CSF and rhEPO is highly effective in achieving a stable and long-lasting erythroid response in many patients with MDS and low blast count.
Increased apoptosis in bone marrow B lymphocytes but not T lymphocytes in myelodysplastic syndrome
Blood, 2003
The hallmark of myelodysplastic syndrome (MDS) is enhanced apoptosis in myeloid, erythroid, and megakaryocytic cells in the bone marrow leading to ineffective hematopoiesis. Recent studies suggested that immunological and microenvironmental factors play a role in the pathophysiology of this disease. We report a significant increase in apoptosis in bone marrow B lymphocytes in MDS as compared to that found in acute myeloid leukemia and healthy controls. Furthermore, we demonstrate that patients with refractory anemia with excess blasts in transformation (RAEB-T) had apoptosis levels in lymphocytes similar to those seen in other subtypes of MDS. Our findings suggest that the alterations in B lymphocytes in the form of increased apoptosis can be seen in MDS and support the concept that immune modulation plays a role in the pathophysiology of