Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023467 (acute myeloid leukemia)
 35,200 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To determine whether the biological characteristics of leukemic cells change after repeated chemotherapy, we compared the proliferative activity and drug sensitivity of leukemic blast progenitors in 7 patients with acute myeloblastic leukemia at diagnosis and in relapse. The proliferative activity of leukemic blast progenitors was assessed based on primary (PE1) and secondary (PE2) colony formation in methylcellulose culture and on the recovery of clonogenic cells in suspension culture. The effect of cytosine arabinoside (Ara-C) on leukemic blast progenitors was studied both in methylcellulose and in suspension cultures. PE1 and PE2 values varied among the patients. PE2 of 4 patients out of 7 patients became significantly higher in relapse than at diagnosis. The sensitivity to Ara-C of leukemic blast progenitors deteriorated in 5 patients in relapse. The results suggest that the biological nature in terms of proliferative activity and Ara-C sensitivity of leukemic blast progenitors may change in the clinical course after chemotherapy.
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PMID:Comparison of the proliferative activity and sensitivity to cytosine arabinoside of leukemic blast progenitors in acute myeloblastic leukemia at diagnosis and in relapse. 141 57

In this study, we evaluated the individual in vitro sensitivity of fresh acute myeloid leukemia (AML) cells to VP-16, and attempted to correlate VP-16 cytotoxicity with AML cell growth characteristics and drug-induced DNA single-strand breaks (SSB). Primary (PE1) colony inhibition assays allowed us to characterize two distinct groups of AML: group I (patients 1 through 6), which displayed sensitivity to VP-16 similar to that of normal CFU-GM (IC90 of 20.52 +/- 2.44 micrograms/mL v 20.48 +/- 2.23 micrograms/mL after 1 hour drug exposure, respectively); and group II (patients 7 through 11), which was more sensitive to VP-16 (IC90 of 7.26 +/- 2.93 micrograms/mL, P = .004). Subsequently, groups I and II were termed normosensitive and hypersensitive, respectively. This objective VP-16 sensitivity classification, as determined by PE1, remained unaltered when assessed by secondary (PE2) colony inhibition assay (evaluating the self-renewal fraction of AML progenitors), or by cytofluorometric viability assay (evaluating the ultimately differentiated blast cell population). These findings would suggest that individual sensitivity to VP-16 of a particular cell population is maintained throughout CFU-AML differentiation. Finally, we report that sensitivity of AML cells to VP-16 did not correlate either with cell growth characteristics or with SSB generation. Indeed, AML cell sensitivity to VP-16 appeared more closely related to DNA repair kinetics after drug removal, ie, hypersensitivity being essentially characterized by a prolonged retention of SSB during the posttreatment period. Interestingly, the established HL-60 cell line, which presented greater sensitivity to VP-16 cytotoxicity than KG1, HEL, and K562, was also found to exhibit delayed DNA SSB repair kinetics, as compared with the other AML cell lines. These results suggest that hypersensitivity to VP-16 of some AML cells may be related to a deficient DNA-repair mechanism.
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PMID:Sensitivity of fresh acute myeloid leukemia cells to etoposide: relationship with cell growth characteristics and DNA single-strand breaks. 151 45

This study aimed to evaluate the effect of melphalan on both terminal divisions and self-renewal capacity of acute myeloblastic leukemia (AML) progenitors (colony-forming units, CFU-L) grown in methylcellulose. Terminal divisions and self-renewal were assayed by primary (PE1) and secondary (PE2) colony formation, respectively. Thirteen cases of AML, were tested. Melphalan induced a negative exponential dose-effect on CFU-L survival. Moreover, melphalan was equally effective in inhibiting CFU-L growth in both PE1 and PE2 assays, with D10 values of 1.53 +/- 0.17 micrograms/ml and 1.59 +/- 0.21 micrograms/ml for PE1 and PE2, respectively (p = 0.48). Cytotoxicity of melphalan on CFU-L did not differ significantly from that observed for normal hemopoietic granulocyte-macrophage colony-forming units, erythroid burst-forming units, and granulocyte-erythroid-macrophage-megakaryocyte progenitors. Mafosfamide-lysine, a stable cyclophosphamide congener, strongly inhibited primary colony formation (PE1) with a D10 value of 14.46 +/- 1.76 micrograms/ml, but was much less efficient in the PE2 assay. Our findings suggest that the self-renewal capacity of AML progenitors can be differentially affected by alkylating agents. Moreover, since it is now considered that chemotherapy should be preferentially directed against the self-renewal of leukemic progenitors, melphalan might offer a greater potential than cyclophosphamide or cyclophosphamide derivatives in the therapy of AML.
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PMID:Effect of melphalan against self-renewal capacity of leukemic progenitors in acute myeloblastic leukemia. 156 57

The in vitro growth activities and drug sensitivities of leukemic blast progenitors were compared among the subgroups of acute myelocytic leukemia (AML) classified according to the French-American-British (FAB) cooperative group. Leukemic cells separated from the peripheral bloods of AML patients were cultured in methylcellulose media, and the plating efficiencies of primary colonies (PE1) and secondary colonies after replating (PE2) were determined. PE1 and PE2 have been considered to reflect the capacities of terminal divisions and self-renewal of leukemic blast progenitors, respectively. PE1 and PE2 were variable among AML patients; these findings suggest that AML is a heterogeneous disease in terms of the proliferative activities of leukemic cells. No significant correlation was noted between PE1 or PE2 and the AML subtype. The sensitivities to cytosine arabinoside (Ara-C) of leukemic blast progenitors were studied in methylcellulose and suspension cultures. Ara-C sensitivity was not significantly correlated with the AML subtype, either. In contrast, there was statistically significant correlation between PE2 and the remission outcome of the patients, whereas PE1 was not significantly associated with the clinical outcome. The results in the present study indicate that the proliferative activity, especially self-renewal capacity, of leukemic blast progenitors is highly predictive of the prognosis of AML patients but is not significantly correlated with the AML subtype classified by the blast morphology.
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PMID:The in vitro growth patterns and drug sensitivities of leukemic blast progenitors among the subtypes of acute myelocytic leukemia. 162 9

Current knowledge is inadequate to explain the different patterns of blast cell accumulation in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). We compared the growth patterns of blast cell progenitors (CFU-L) in 23 patients with advanced MDS and 32 patients with de novo AML. Circulating blast progenitors were identified in 74% of MDS and 81% of AML samples. Primary plating efficiencies (PE1) were similar in both disorders, despite marked differences in peripheral blast cell concentrations. By cytological and cytochemical examination, colonies from MDS patients were indistinguishable from those obtained in AML. Cell cycle status was assessed by loss of colony formation following short-term exposure to cytosine arabinoside. CFU-L suicide rates (median, range) were 40% (12% to 77%) in MDS and 60.5% (27% to 98%) in AML. Actively proliferating blast cell progenitors are thus not confined to AML, but are also present in the majority of MDS patients. An important difference between MDS and AML was found when self-renewal capacity of CFU-L was examined by means of secondary plating efficiencies (PE2). Colonies could be successfully replated in 74% of AML cases. PE2 showed marked heterogeneity (2 to 730 colonies/10(5) mononuclear cells), with some values indicating excessive self-renewal capacity of CFU-L. In contrast, 62% of the MDS specimens failed to produce any secondary colony growth, and PE2 in the remaining cases was low (5 to 99/10(5) MNC). We conclude that a different balance between self-renewal and determination could be responsible for a slower pace of clonal expansion in MDS, even if the proliferative activity of clonogenic cells is similar to that in AML.
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PMID:Comparison of in vitro growth characteristics of blast cell progenitors (CFU-L) in patients with myelodysplastic syndromes and acute myeloid leukemia. 163 20

We examined the effect of a 96-h exposure to 1-beta-D arabinofuranosylcytosine (Ara-C) and deoxycytidine (dCyd) in medium lacking an exogenous source of colony-stimulating activity (phytohemagglutinin-stimulated leukocyte-conditioned medium, PHA-LCM) on the survival of normal human committed myeloid progenitor cells (day-7 and day-14 granulocyte-macrophage colony-forming units [CFU-GM] as well as leukemic progenitors (leukemic colony-forming units, L-CFU) derived from myeloblasts obtained from 13 patients with acute nonlymphocytic leukemia (ANLL). Coadministration of Ara-C (20-50 microM) in conjunction with dCyd (50-100 microM) permitted the survival of an average of 9%-57% of day-7 CFU-GM and 32%-65% day-14 CFU-GM, depending upon the relative concentrations of dCyd and Ara-C. In contrast, exposure of leukemic myeloblasts to identical regimens resulted in considerably greater reductions in L-CFU survival, which in general exceeded 90% and in some cases was 100%. In addition, exposure of leukemic myeloblasts to Ara-C and dCyd for 96 h in culture medium lacking PHA-LCM eliminated the secondary plating efficiency (PE2) of leukemic colonies in 11 of 13 samples assayed and reduced values dramatically in the remaining 2. Substantial preservation of CFU-GM formation was also noted when normal bone marrow samples depleted of T cells and marrows obtained from two patients with ANLL in remission were assayed. These studies suggest that in contrast to certain normal committed myeloid progenitor cells, leukemic progenitors, particularly those with self-renewal capacity, are highly vulnerable to a prolonged exposure to Ara-C and dCyd in the absence of an exogenous source of colony-stimulating activity. They also raise the possibility that a combined regimen utilizing chemotherapeutic agents in conjunction with modifications of long-term culture techniques may represent a novel approach to the ex vivo purging of leukemic cells from bone marrow in conjunction with autologous bone marrow transplantation.
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PMID:The effect of a prolonged in vitro exposure to 1-beta-D arabinofuranosylcytosine and deoxycytidine on the survival of normal (CFU-GM) and leukemic (L-CFU) human myeloid progenitor cells in suspension culture. 229 68

The initial clinical and biological parameters, including clonogenic leukemic cell (CFU-L) assay, were reviewed for their prognostic significance in a cohort of 188 adult patients with newly diagnosed untreated acute myeloid leukemia (AML). Almost all patients received induction therapy with daunorubicin (DNR) and cytarabine (Ara-C) according to the European Organization for Research and Treatment of Cancer (EORTC) AML 5 to AML 9 trials. Bone marrow samples from 116 representative patients were obtained for CFU-L assay with an efficiency percentage of 89.6%; 76 patients had a measurement of the CFU-L self-renewal capacity (second plating efficiency [PE2]) and 91 patients had CFU-L inhibition test after exposure to DNR and/or Ara-C. The prognostic significance of parameters such as age, hematological antecedent, WBC count, liver enlargement, and Auer rods is confirmed in the present study. Moreover, high platelet and polymorphonuclear counts appeared to be related to resistance to induction course. However, through multivariate analysis, CFU-L sensitivity to drugs and self-renewal capacity appeared to be major independent prognostic factors in AML. A low CFU-L inhibition in the presence of the DNR and Ara-C combination correlates with a poorer complete remission (CR) rate, but not with CR duration. Patients with the lower PE2 values experienced both higher CR rate and longer CR duration. The practical interest of CFU-L study remains to be defined but, at least, PE2 measurement could be considered in the future as a major variable in determining therapeutic aggressiveness.
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PMID:Multivariate analysis of prognostic factors in acute myeloid leukemia: value of clonogenic leukemic cell properties. 271 4

The effects of human recombinant tumor necrosis factor type alpha (rTNF alpha) on the blast progenitors from 14 acute myeloblastic leukemia (AML) patients and 1 chronic myelogenous leukemia patient in blastic crisis were studied in methylcellulose and suspension cultures. Blast progenitors renew themselves and/or undergo terminal divisions. Plating efficiency of primary colony formation (PE1) in methylcellulose, which is considered to reflect the terminal divisions of blast progenitors, was suppressed by rTFN alpha in a dose-dependent manner in all cases. Plating efficiency of secondary colony formation (PE2) and the recovery of clonogenic cells in suspension culture, which are considered to reflect the self-renewal capacity of blast progenitors, were also suppressed by rTNF alpha in a dose-dependent manner in almost all cases. rTNF alpha also inhibited both PE2 and clonogenic cells in suspension culture, even in relapsed AML patients who were very refractory to intensive chemotherapies. The results demonstrate that rTNF alpha inhibits not only terminal divisions but also the self-renewal capacity of leukemic blast progenitors. The finding that rTNF alpha suppressed the self-renewal capacity of leukemic blast progenitors proposes the utility of rTNF alpha to AML therapy.
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PMID:Effects of recombinant human tumor necrosis factor on the self-renewal capacity of leukemia blast progenitors in acute myeloblastic leukemia. 276 17

A minority of blast cells in acute myeloblastic leukemia (AML) form colonies in culture in methylcellulose when stimulated by media conditioned by normal leukocytes in the presence of phytohemagglutinin (PHA-LCM). Blast colonies can be replated successfully, either as pooled cells or suspensions from single colonies. However, the plating efficiency declines with repeated passages, and more than four subcultures have not been achieved. In this study, blast populations were cultured in suspension, with fetal calf serum, alpha-minimal essential medium and PHA-LCM. In cells from 17 of 18 patients, exponential growth of clonogenic blast cells was maintained for six to seven days without reculturing. Colonies obtained from progenitors taken from liquid culture and replated in methylcellulose were replated to obtain the secondary plating efficiency (PE2). In 14 cases, this value was maintained or increased. In three instances, PE2 fell following culture in methylcellulose. When cells in suspension were recultured, exponential growth continued. In nine instances, exponential growth was maintained for from seven to 70 days. During this time, PE2 was maintained. Results from experiments using velocity sedimentation separation and analysis of single colonies were consistent with the view that the increase in clonogenic cells in suspension was a manifestation of their self-renewal capacity. The observations also support a model of blast progenitor growth that contains the postulate that these are capable not only of self-renewal but also of determination-like events leading to loss of proliferative capacity.
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PMID:The proliferation in suspension of the progenitors of the blast cells in acute myeloblastic leukemia. 385 45

The blast population in acute myeloblastic leukemia (AML) contains cells capable of forming blast-cell colonies in culture. The purpose of this study was to measure the effects of hydrocortisone on this process, using two end-points. First, we measured the effects of increasing concentrations of hydrocortisone on the primary plating efficiency of T-lymphocyte-depleted blast cell preparations from AML peripheral blood. Second, colonies forming in the presence or absence of the hormone were pooled and replated; changes in the plating efficiencies (secondary plating efficiency or PE2) of these suspensions reflected the effect of the hormone on blast progenitor self-renewal. For comparison, we measured the hydrocortisone dose response curves for normal granulopoietic and T-lymphocyte colony-formation. The latter showed little individual variation; T-lymphocyte colony-formation was regularly sensitive to the hormone while granulopoietic colony-formation was resistant. In contrast, wide variations were found in the hydrocortisone dose response curve for blast from 24 patients with AML (FAB 1-6). A significant association was found between successful remission induction and resistance to hydrocortisone in 24 treated patients. The association was maintained when the data was stratified by other risk factors, including PE2 and the presence of blasts bearing immunologically-defined markers of more than one differentiation lineage (lineage infidelity). We propose that sensitivity to hydrocortisone may reflect the passage of blast cells through lymphopoiesis-associated components of differentiation programs. From this point of view, the poor prognosis associated with sensitivity of blast progenitors to hydrocortisone may be similar to the response-failure of patients whose blasts exhibit lineaged infidelity when tested with immunological procedures.
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PMID:Response to hydrocortisone of blast progenitors in acute myeloblastic leukemia: an aspect of lineage infidelity. 387 38


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