methylcellulose and Leukemia--Myeloid--Acute

Monocytic leukemia zinc finger protein (MOZ, MYST3, or KAT6A) is a MYST-type acetyltransferase involved in chromosomal translocation in acute myelogenous leukemia (AML) and myelodysplastic syndrome. MOZ is established as essential for hematopoiesis; however, the role of MOZ in AML has not been addressed. We propose that MOZ is critical for AML development induced by MLL-AF9, MLL-AF10, or MOZ-TIF2 fusions. Moz-deficient hematopoietic stem/progenitor cells (HSPCs) transduced with an MLL-AF10 fusion gene neither formed colonies in methylcellulose nor induced AML in mice. Moz-deficient HSPCs bearing MLL-AF9 also generated significantly reduced colony and cell numbers. Moz-deficient HSPCs expressing MOZ-TIF2 could form colonies in vitro but could not induce AML in mice. By contrast, Moz was dispensable for colony formation by HOXA9-transduced cells and AML development caused by HOXA9 and MEIS1, suggesting a specific requirement for MOZ in AML induced by MOZ/MLL fusions. Expression of the Hoxa9 and Meis1 genes was decreased in Moz-deficient MLL fusion-expressing cells, while expression of Meis1, but not Hoxa9, was reduced in Moz-deficient MOZ-TIF2 AML cells. AML development induced by MOZ-TIF2 was rescued by introducing Meis1 into Moz-deficient cells carrying MOZ-TIF2. Meis1 deletion impaired MOZ-TIF2-mediated AML development. Active histone modifications were also severely reduced at the Meis1 locus in Moz-deficient MOZ-TIF2 and MLL-AF9 AML cells. These results suggest that endogenous MOZ is critical for MOZ/MLL fusion-induced AML development and maintains active chromatin signatures at target gene loci.

Topics: Animals; Chromatin; Hematopoiesis; Histone Acetyltransferases; Leukemia, Myeloid, Acute; Methylcellulose; Mice

Ectopic expression of c-Myc (Myc) in most primary cell types results in programmed cell death, and malignant transformation cannot occur without additional mutations that block apoptosis. The development of Myc-induced lymphoid tumors has been well studied and supports this model. Myc can be upregulated in acute myeloid leukemia (AML), but its exact role in myeloid leukemogenesis is unclear. To study its role in AML, we used a murine stem cell virus (MSCV) retroviral gene transfer/transplantation system to broadly express Myc in the bone marrow of mice either alone or in combination with antiapoptotic mutations. Myc expression in the context either of Arf/Ink4a loss or Bcl-2 coexpression induced a mixture of acute myeloid and acute lymphoid leukemias (AML+ALL). In the absence of antiapoptotic mutations however, all mice transplanted with MSCV-Myc (100%, n = 110) developed AML exclusively. MSCV-Myc-induced AML was polyclonal, readily transplantable, possessed an intact Arf-p53 pathway, and did not display cytogenetic abnormalities by spectral karyotyping (SKY) analysis. Lastly, we found that Myc preferentially stimulated the growth of myeloid progenitor cells in methylcellulose. These data provide the first direct evidence that Myc is a critical downstream effector of myeloid leukemogenesis and suggest that myeloid progenitors are intrinsically resistant to Myc-induced apoptosis.

Topics: Animals; Apoptosis; Blotting, Western; Bone Marrow Cells; Bone Marrow Transplantation; Cell Line; Cell Transplantation; Cyclin-Dependent Kinase Inhibitor p16; DNA; Flow Cytometry; Gene Transfer Techniques; Green Fluorescent Proteins; Humans; Immunophenotyping; Karyotyping; Leukemia, Myeloid, Acute; Methylcellulose; Mice; Mice, Inbred BALB C; Mutation; Plasmids; Proto-Oncogene Proteins c-bcl-2; Proto-Oncogene Proteins c-myc; Retroviridae; Sequence Analysis, DNA; Time Factors; Up-Regulation

It is well known that ABMT in acute myeloid leukemia (AML) often results in delayed hematopoietic engraftment, but the reason behind this has not been resolved. Previous studies have largely dealt with measurements of committed myeloid progenitors as surrogate markers for hematopoiesis.. Measurements of Week 5 cobblestone area forming cells (CAFC) and stromal-cell growth in BM autografts from 14 AML patients were compared with those from 10 NHL patients.. Grafts achieved from the AML patients contained a significantly lower total number of CAFC than those from the NHL patients. The reason for this was a lower total amount of mononuclear cells (MNC) obtained during harvest procedure (mean 0.4 x 10(8)/kg for AML, versus 0.8 x 10(8)/kg for NHL). In contrast, the frequency of CAFC was comparable both between patient groups (mean 1.47, range 0.15-6.33 per 10(4) MNC for AML versus mean 1.47, range 0.53-3.57 per 10(4) MNC for NHL) and compared with that of eight normal donors (mean 1.12, range 0.73-1.73 per 10(4) MNC). An inverse relationship was observed between the total CAFC number in the grafts and the hematopoietic reconstitution of both granulocytes > or = 2.0 x 10(9)/L and thrombocytes > or = 50 x 10(9)/L, in which the level of 9.0 x 10(3) CAFC/kg implied a prompt engraftment for both patient groups. Whereas the stromal cell outgrowth in vitro from 8/10 NHL patients was similar to that of six normal donors, only a few stromal cells appeared in the majority of nine evaluable AML patients.. A decreased total CAFC content, as well as an inferior stromal-cell function, may be critical elements for prolonged hematopoietic reconstitution in AML.

Topics: Adult; Blood Platelets; Bone Marrow Cells; Bone Marrow Transplantation; Cell Division; Humans; Leukemia, Myeloid, Acute; Lymphoma, Non-Hodgkin; Methylcellulose; Middle Aged; Neutrophils; Stromal Cells; Time Factors

The clonal growth of human acute leukemia cell line (K562) and acute myeloid leukemia cells in the serum-free culture (SFC) was studied in order to establish a SFC system which could replace the effects of serum by using semi-solid methylcellulose culture technique. Our results showed that the clonal growth of K562 cells in semi-solid culture was dependent on exogenous serum. The K562 could be grown in SFC supplemented with 4 major replacing substances. The multifactor and multilevel orthogonal experiment demonstrated that the colony formation was statistically influenced by the 4 replacing substances at various concentrations (P < 0.01). Among them, bovine serum albumin had greatest effect on clonal growth of K562 cells with the optimal concentration being 15 mg/L, followed by transferring, cholesterol and insulin with their optimal concentrations being of 150 mg/L, 7.8 mg/L and 7.0 mg/L respectively. SFC system was formed with the 4 substances at their optimal concentrations. Colony formation of the blast cells in 10 patients with acute myeloid leukemia was observed in this SFC system. There was a heterogeneity of acute myeloid leukemia cells among the 10 patients in response to the growth substances. In SFC system, there was a linear relationship between the number of the clonal formation and the count of the added cells, indicating the colony growth of the cells. Primary acute leukemia cells maintained in SFC system in 10 cases could completely form clones. The colony formation number in some cases in SFC system was more than that of the serum-containing culture. The SFC system could partially replace the serum for study of the clonal formation of human leukemia cells.

Topics: Cell Division; Culture Media, Serum-Free; Humans; K562 Cells; Leukemia, Myeloid, Acute; Methylcellulose; Tumor Cells, Cultured; Tumor Stem Cell Assay

To evaluate the radiosensitivity of self-renewing progenitor cells in acute myeloblastic leukemia (AML), we have compared the radiosensitivity of the cells grown either in methylcellulose alone for 7 days, or first in suspension culture for 7 days before being plated in methylcellulose. Methylcellulose selects for terminal-dividing cells and suspension cultures have been developed because they allow self-renewal to occur: The exponential growth of the progenitors of AML cultured in suspension is due to self-renewal.. Cells were harvested from previously untreated leukemic human bone marrows. The myeloblastic lineage of the colonies was assessed by morphological, cytochemical, and immunophenotypic analysis, and by the use of growth factors that did not stimulate the growth of T-lymphocytes. The cell-cycle distribution of the blasts was analyzed by flow cytometry and was comparable for all samples. The irradiation was performed with gamma-photons at a dose-rate of 0.05 Gy/min, similar to the clinical conditions used in our institution for total body irradiation (TBI).. The culture methods selected aggressive leukemias. There were large variations of the individual radiosensitivity whatever culture method was used. The progenitor cells capable of self-renewal were more radiosensitive than terminal dividing cells. In two cases, a shoulder was found in the initial part of the cell-survival curves of cells capable of self-renewal. In these two cases, the best fit for the data was the linear quadratic model (survival = e-alpha D-beta D2) with alpha/beta values of 1.49 Gy and 3.12 Gy, respectively.. The very low values of alpha/beta suggest a reduced antileukemic effect in case of fractionated TBI, and may lead to more reliable screening methods to determine the most appropriate technique for radiation ablation of bone marrow prior to bone marrow transplantation (BMT).

Topics: Adolescent; Adult; Aged; Blast Crisis; Bone Marrow; Cell Cycle; Cell Differentiation; Cell Division; Cell Survival; Culture Techniques; Dose-Response Relationship, Radiation; Female; Flow Cytometry; Gamma Rays; Hematopoietic Stem Cells; Humans; Leukemia, Myeloid, Acute; Male; Methylcellulose; Middle Aged; Photons; Tumor Cells, Cultured

We studied bone marrow separated with 0.05% methylcellulose and cryopreservatized with liquid nitrogen. The separation time was 43 minutes. The collection rates of nuclear cells and CFU-GM were 79.0 +/- 5.10% and 93.0 +/- 3.10% in normal marrow samples and 83.4 +/- 15.45% and 91.0 +/- 8.32% in those of acute leukemia patients. The rate of residual erythocytes was 12.5% and the bone marrow volume could be reduced by 55.2%. Application of this technique to autologous bone marrow transplantation in four patients with acute leukemia reconstituted all of their hemopoietic functions and no toxic side effect was found after transplantation.

Topics: Bone Marrow; Bone Marrow Transplantation; Cell Separation; Cryopreservation; Humans; Leukemia, Myeloid, Acute; Methylcellulose; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Transplantation, Autologous

The purpose of this paper was to ascertain whether results obtained in cell cultures of AML clonogenic blast cells would provide a useful model for a clinical regimen that combines fludarabine (F-ara-AMP) and cytosine arabinoside (ara-C). In the cultures the nucleoside F-ara-A was used. Blast cells from the continuous lines OCI/AML-2 and OCI/AML-3 were grown, either in methylcellulose to quantify clonogenic cells, or in suspension to measure self-renewal as reflected in changes in numbers of clonogenic cells. F-ara-A, like ara-C, was found to be more toxic to blast stem cells in suspension than in the clonogenic assay, indicating that F-ara-A might, in addition to general cytotoxicity, have some specific inhibitory effects on self-renewing stem cells. F-ara-A was less cytotoxic than ara-C; but, when F-ara-A was given before ara-C, synergism was seen at some F-ara-A doses, as manifested by increased ara-C cytotoxicity. In contrast, when ara-C was given before F-ara-A, protection was observed. Control experiments make it unlikely that this effect is related to changes in the cell cycle following ara-C exposure. We conclude that the cellular studies reported here confirm previous pharmacological data indicating that F-ara-A before ara-C increases the effectiveness of ara-C by increasing the accumulation of ara-CTP. However the present experiments show that the synergism between F-ara-A and ara-C is dependent on both dose and schedule.

Topics: Antineoplastic Agents; Cell Survival; Cells, Cultured; Cytarabine; Drug Administration Schedule; Drug Synergism; Humans; In Vitro Techniques; Leukemia, Myeloid, Acute; Methylcellulose; Vidarabine

Recombinant growth factors have been shown to alter the sensitivity of acute myeloblastic leukemia (AML) blast cells to cytosine arabinoside (ara-C) in culture. The mechanism is controversial and suggestions for it include changes in ara-C metabolism, changes in cell cycle parameters, and changes in the balance between self-renewal and determination in blast stem cells. We addressed this issue by measuring the cisplatin sensitivity of freshly obtained AML blasts in rG-CSF, rGM-CSF, or the two together. For comparison, simultaneous measurements of ara-C sensitivity were made. We found that exposure to different factors in suspension altered the cisplatin sensitivity of AML blasts in the same direction as the change observed in ara-C sensitivity. Similar changes in cisplatin sensitivity were seen when cells were briefly exposed to the drug, washed, and then grown in suspension in the presence of different growth factors. Control experiments showed that the conditions in suspension, not in the clonogenic assay in methylcellulose, were responsible for the changes in cisplatin sensitivity. The capacity of high specific activity to inactivate clonogenicity was tested at several times under growth conditions which altered the sensitivity of cells to cisplatin. Whereas changes in survival after 3HTdR and cisplatin both were seen with time, growth conditions that altered cisplatin sensitivity were not associated with changes in 3HTdR toxicity. The data do not support explanations of the effects of growth conditions on drug toxicity which depend either on drug metabolism or cell cycle effects. Instead, the findings are consistent with a model that postulates an association between drug sensitivity and the balance between self-renewal and differentiation in the blast population.

Topics: Cell Cycle; Cell Division; Cell Survival; Cisplatin; DNA, Neoplasm; Granulocyte Colony-Stimulating Factor; Granulocyte-Macrophage Colony-Stimulating Factor; Humans; Leukemia, Myeloid, Acute; Methylcellulose; Recombinant Proteins; Thymidine; Tritium; Tumor Cells, Cultured; Vidarabine

The responses to retinoic acid (RA) of acute myeloblastic leukemia (AML) blasts and normal hemopoietic progenitors was examined under defined growth factor conditions. For the leukemic cells marked patient to patient variation was seen; blast colony formation by cells from some patients was stimulated by RA without growth factors or in the presence of recombinant granulocyte colony-simulating factor (rG-CSF), recombinant granulocyte-macrophage-CSF rGM-CSF and recombinant interleukin-3 (rIL-3); for other populations inhibition was observed under the same conditions. Some blast cells were stimulated by RA in the presence of rGM-CSF and rIL-3 and inhibited when cultured with RA and rG-CSF. Supernatants prepared from blasts cultured with RA and growth factors did not show activities that were not readily explained by the carry-over of growth factors; this result did not provide evidence that RA and growth factors interact to produce factors. Titrations of RA showed that activity was first observed at concentrations of 10(-9) M and was maximum at concentrations of 10(-7) M. Different effects of RA in combination with rG-CSF compared with rGM-CSF or IL-3 were not seen when the cells were tested in suspension culture rather than in methylcellulose, a finding that may be interpreted to mean that the interaction between RA and factors affects terminally-dividing blast cells. Three normal bone marrow samples were cultured with RA and growth factors. Colony formation was stimulated by RA in the presence of rGM-CSF or rIL-3 but inhibited by RA with rG-CSF. Thus a differential effect of RA in combination with growth factors occurs in normal hemopoietic cells and persists in some AML populations.

Topics: Bone Marrow; Cells, Cultured; Colony-Forming Units Assay; Colony-Stimulating Factors; Culture Media; Dose-Response Relationship, Drug; Drug Interactions; Humans; Leukemia, Myeloid, Acute; Lymphocyte Activation; Lymphocytes; Methylcellulose; Tretinoin

To determine the growth requirement of leukemic blast progenitors in acute myeloblastic leukemia (AML), leukemic cells from the peripheral blood of eight AML patients were cultured in the serum-free culture system. Blast progenitors made colonies in methylcellulose culture and showed exponential growth in suspension culture, although the growth of blast progenitors in the absence of fetal calf serum (FCS) in some patients was inferior to that in the FCS-enhanced culture system. Recombinant human granulocyte colony-stimulating factor (rhG-CSF) stimulated the growth of blast progenitors in a dose-responsive manner. When cells were cultured at high cell density, blast colonies were formed even in the absence of CSF. Irradiated blasts also supported the growth of intact blast progenitors. These results confirm the finding noted in the FCS-enhanced culture studies that granulopoietic factor, G-CSF, plays an important role on the leukemic growth. The importance of cell to cell interaction for the growth of blast progenitors was also confirmed.

Topics: Blast Crisis; Blood Cell Count; Blood Physiological Phenomena; Cell Division; Colony-Stimulating Factors; Culture Media; Granulocyte Colony-Stimulating Factor; Humans; Leukemia, Myeloid, Acute; Methylcellulose; Neoplastic Stem Cells; Phagocytes; Recombinant Proteins; Tumor Cells, Cultured

The use of a semisolid support like methylcellulose (MC) in a clonogenic assay prevents cell migration and nonspecific aggregation. However, the inhibitory effect of MC on myeloid cell lines has been reported. To assess the effect of MC on human leukemic progenitor cell growth (acute myeloblastic leukemia colony-forming units, AML-CFU), increasing concentrations of MC (0.36%, 0.72%, and 1.44%) were added in a double-feeder culture system. T-lymphocyte-depleted leukemic cells from 12 patients with AML were cultured in the presence of 2.5% phytohemagglutinin (PHA) in a liquid and a semisolid (MC) medium over a leukocyte feeder layer. The leukemic nature of the colonies was confirmed by cytogenetic studies. The median cloning efficiency in the optimal MC assay system was significantly higher (217 leukemic colony-forming units [CFU-L]/5 x 10(4) cells) than the one obtained in the liquid assay system (72.5 CFU-L/5 x 10(4) cells). However, three patterns of growth were observed: 1) colony formation was significantly better in MC than in the liquid assay system (seven of ten cases), 2) there was no difference in growth response (three of ten cases), and 3) colony formation was significantly better in the liquid assay system (one of ten cases). In the semisolid assay system, colony growth was dependent on MC concentration and varied among individual patients. A striking feature was the partial reduction of AML-CFU growth at 1.44% MC, with complete inhibition in 4/11 cases. This phenomenon was not observed for normal progenitors cultured under the same conditions. Cytological evaluation of AML-CFU showed an incomplete maturation to the myelocyte state, accompanied occasionally by macrophagic differentiation. In contrast, maturation of the granulocyte-macrophage colony-forming unit (CFU-GM) clones was harmonious, resulting in greater than 40% polynuclear cells, even from a 7-day culture. Despite a variable clonal response of leukemic progenitors from individual patients, we conclude that 0.72% MC is the optimal concentration of MC in our system, allowing clonal growth of AML-CFU.

Topics: Cell Division; Cells, Cultured; Clone Cells; Colony-Forming Units Assay; Dose-Response Relationship, Drug; Granulocytes; Hematopoietic Stem Cells; Humans; Leukemia, Myeloid, Acute; Macrophages; Methylcellulose; Phytohemagglutinins; Tumor Cells, Cultured

We describe here the presence of two classes of binding sites for GM-CSF expressed on blasts freshly isolated from five AML patients and one patient with CML in blastic phase: one of high-affinity (38-177 per cell, KD 8-150 pM) and one of low-affinity (121-806 per cell, KD 503-2683 pM). No correlation is observed between the receptor number, receptor affinity, and the growth stimulatory effect of GM-CSF on leukemic blast progenitors. Blasts from two cases showed no or negligible response to GM-CSF but expressed comparable numbers of receptors when compared with the numbers expressed by the sensitive blasts. Our data suggest that significant proliferative effects of GM-CSF can occur at low levels of high-affinity receptor occupancy. Lack of responsiveness to GM-CSF in some AML patients is not correlated to the absence of GM-CSF receptors on leukemic cells. Reduction in the growth of blast progenitors at high concentrations of GM-CSF may be attributed to the differentiating activity of GM-CSF via low-affinity receptors on leukemic cells.

Topics: Binding, Competitive; Cell Division; Colony-Stimulating Factors; Granulocyte-Macrophage Colony-Stimulating Factor; Growth Substances; Humans; Interleukin-3; Iodine Radioisotopes; Kinetics; Leukemia, Myeloid, Acute; Methylcellulose; Neoplastic Stem Cells; Receptors, Cell Surface; Receptors, Colony-Stimulating Factor; Recombinant Proteins; Tumor Cells, Cultured

Blast progenitors in acute myeloblastic leukemia (AML) grow in methylcellulose and suspension cultures. Blast colony formation in methylcellulose culture reflects the terminal divisions of blast progenitors, while secondary colony formation, by replating in methylcellulose and recovering clonogenic cells in suspension culture, reflects the self-renewal of blast progenitors. To analyze the regulatory mechanisms of the proliferation of leukemic blast progenitors, the effects of highly purified native granulocyte colony-stimulating factor (G-CSF) obtained from human squamous cell carcinoma line (CHU-2) on blast progenitors in AML patients were studied in methylcellulose and suspension cultures. Purified G-CSF stimulated the growth of blast progenitors in both culture systems, although sensitivity to G-CSF varied from patient to patient. No obvious maturation of leukemic blasts was noted in suspension culture in the presence of G-CSF. The data suggest that a normal hemopoietic regulator may play a role in the growth of blast progenitors in AML patients.

Topics: Adult; Aged; Cell Transformation, Neoplastic; Colony-Stimulating Factors; Culture Media; Female; Granulocytes; Humans; Leukemia, Myeloid, Acute; Male; Methylcellulose; Middle Aged; Neoplastic Stem Cells; Suspensions; Tumor Stem Cell Assay

The effects of two recombinant human CSFs (G-CSF and GM-CSF) on the growth of blast progenitors from 36 acute myeloblastic leukemia patients were studied in methylcellulose and suspension cultures. Blast colony formation in methylcellulose and the growth of blast progenitors in suspension were stimulated by G-CSF or GM-CSF. Their responses to CSFs were different from those of normal myeloid progenitors. First, the sensitivity of blasts to 0.01 ng/ml of G-CSF and 0.001 ng/ml of GM-CSF was significantly increased compared with normal. Second, in more than 70% of patients, the pattern of the responsiveness to the two CSFs was aberrant compared with ordered response in normal subjects. Third, in about half of the patients, combination of G-CSF and GM-CSF showed synergism for the growth of blast progenitors in both culture methods, whereas negligible or no synergism was observed in normal subjects. Finally, when stimulated by G-CSF, GM-CSF, or both, a significant relationship was noted between blast colony formation in methylcellulose and blast progenitor growth in suspension, suggesting that CSFs do not affect the balance between self-renewal and terminal divisions of blast stem cells.

Topics: Adult; Aged; Cell Division; Colony-Stimulating Factors; Female; Granulocytes; Humans; Leukemia, Myeloid, Acute; Macrophages; Male; Methylcellulose; Middle Aged; Recombinant Proteins; Tumor Stem Cell Assay

The effects of media conditioned by leukemic cells from 11 acute myeloblastic leukemia patients on the growth of autologous blast progenitors were studied. First, it was shown that T-cell-depleted leukemic cells from some patients release high levels of colony-stimulating activity into the culture medium, whereas following further depletion of phagocytic cells, the levels of colony-stimulating activity become undetectable. Second, media conditioned by purified blast cell fraction depleted of both T-cells and phagocytic cells potentiated autologous blast progenitor growth both in methylcellulose and suspension cultures stimulated by optimal concentration of media conditioned by human bladder carcinoma line 5637. Third, media conditioned by these purified blast cells generally did not contain measurable colony-stimulating activity or interleukin 1, whereas substantial levels of granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, and interleukin 1 were observed in media conditioned by human bladder carcinoma line 5637 using bioassays and specific immunological assays. Therefore, purified blast cell fraction from acute myeloblastic leukemia patients appears to produce factor(s) other than granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, or interleukin 1, which potentiate the growth of autologous blast progenitors both in methylcellulose and suspension cultures.

Topics: Adult; Aged; Colony-Stimulating Factors; Culture Media; Female; Humans; Interleukin-1; Leukemia, Myeloid, Acute; Male; Methylcellulose; Middle Aged; Neoplastic Stem Cells; Suspensions; Tumor Cells, Cultured

The genes for the hemopoietic growth factors, GM colony-stimulating factor (CSF) and G-CSF have been cloned, and recombinant material is available for both. We tested these recombinant factors for their effects on the blast cells of acute myeloblastic leukemia (AML). Culture methods are available that support both colony formation by AML blasts and the growth of blast stem cells in suspension. Recombinant GM-CSF is active in both culture systems, although to a varying degree. We found that recombinant G-CSF was also effective; however, the two recombinant factors showed striking synergism for the stimulation of blast growth of cells from five of eight AML patients. In these cases, the combination was equivalent to the stimulating activity of supernatants from the continuous cell line 5637. This conditioned medium (HTB9-CM) is considered the standard for blast growth. Blasts from one of the patients grew without added factor. In another instance, recombinant GM-CSF alone was almost as effective as HTB9-CM. In the third case, both recombinant factors were active, but synergism was not observed and their combined effect was not equivalent to that of HTB9-CM. Both GM-CSF and G-CSF were active on normal bone marrow granulopoietic progenitors, but synergism was not observed. We conclude that the marked heterogeneity observed when AML blasts are examined by other criteria is also observed when their response to growth factors is evaluated.

Topics: Acute Disease; Adolescent; Adult; Aged; Cell Line; Colony-Forming Units Assay; Colony-Stimulating Factors; Culture Media; Drug Synergism; Granulocyte Colony-Stimulating Factor; Granulocytes; Humans; Interleukin-3; Leukemia, Myeloid, Acute; Macrophages; Methylcellulose; Middle Aged; Recombinant Proteins

Sensitivities to drugs acting on cells in culture can be measured as dose-response curves, provided a quantitative assay is available for a relevant cell function. We have used two such assays in the study of the blast cells of acute myeloblastic leukemia. Colony formation in culture with methylcellulose detects principally terminal divisions, while growth of clonogenic cells in suspension reflects self-renewal. In a previous study different cytosine arabinoside and 5-azacytidine dose-response curves were obtained with the two assays. For the former the slope of the dose-response curve measured in suspension was steeper than that obtained using the clonogenic assay. For the latter, 5-azacytidine, the relationship between sensitivity in suspension and in methylcellulose was reversed. Further, for cytosine arabinoside, sensitivity in suspension but not in methylcellulose was associated with successful remission-induction. In this article we report an association between 5-azacytidine sensitivity in suspension and successful remission induction, for patients treated only with high-dose cytosine arabinoside. There was no correlation between the 5-azacytidine dose-response curve in methyl-cellulose and clinical outcome. A model is presented that may explain these findings, based on the hypothesis that there are genetic mechanisms responsible for blast cell renewal.

Topics: Adult; Aged; Aged, 80 and over; Azacitidine; Cell Division; Colony-Forming Units Assay; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Humans; Leukemia, Myeloid, Acute; Methylcellulose; Middle Aged

The blast stem cells of acute myeloblastic leukemia (AML) respond in cell culture to growth factors by both self-renewal and terminal divisions. Both of these functions have been shown to be stimulated by the recombinant growth factors granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF). In this paper, recombinant gibbon interleukin-3 (IL-3), homologous to human IL-3, was tested on blast cells and compared with the effects of GM-CSF, G-CSF, and medium conditioned by the bladder cell line 5637 (5637-CM). We found that IL-3 was an effective stimulator of blast renewal and terminal divisions. However, great patient-to-patient variation was found. A graphic method of presenting complex comparisons between growth factors is also included.

Topics: Acute Disease; Blood Cells; Bone Marrow; Bone Marrow Cells; Cell Count; Cells, Cultured; Cytological Techniques; Humans; Interleukin-3; Leukemia, Myeloid, Acute; Methylcellulose; Recombinant Proteins; Recombination, Genetic; Tumor Stem Cell Assay

Two culture methods are available for the study of the blast cells of acute myeloblastic leukemia (AML). One is an assay for clonogenic precursors; it depends on their ability to form blast colonies in culture in the presence of methylcellulose and suitable growth factors. The other assesses the growth of blast cells in suspension culture, where growth is measured by increasing numbers of clonogenic cells. We have compared the two methods as assays for the cytotoxic effects of the chemotherapeutic drug cytosine arabinoside (Ara-C). Marked patient-to-patient variation was found using either method; however, the slopes of the dose-response curves were usually greater when cells were exposed to drug in suspension rather than in methylcellulose. Control experiments showed that the difference could not be explained by drug carry-over from the suspension cultures to the methylcellulose plates when clonogenic cells in the suspensions were assessed. Further, the survival curves for Adriamycin were very similar, regardless of which assay was used. No correlation was found between D10 Ara-C values measured in suspension or in methylcellulose. However, a significant association with outcome was found between D10 Ara-C in suspension and response to treatment with a regimen in which Ara-C was the only chemotherapeutic agent used. No such association was detected when the D10 values obtained with the clonogenic assay were compared with outcome for the same group of 15 patients. Finally, a feasibility experiment was performed in which blast cells were exposed to Ara-C repeatedly during exponential growth over 238 days. A dose-related inhibition of growth was observed; no evidence was seen of emerging drug-resistant cells. Nor did the morphology of the cells change as a result of drug exposure. We conclude that drug sensitivities of AML blast cells in culture are dependent on measurement methods, even when techniques affecting cell proliferation are compared. Measurements of drug sensitivity in culture may best be interpreted when the bases of the assay systems are understood.

Topics: Adult; Aged; Cell Survival; Colony-Forming Units Assay; Cytarabine; Dose-Response Relationship, Drug; Doxorubicin; Humans; Leukemia, Myeloid, Acute; Methylcellulose; Middle Aged; Suspensions; Tumor Stem Cell Assay

Recent observations indicating that the HL-60 human acute promyelocytic leukemia cell line contains a minor eosinophil population in addition to neutrophil and mononuclear phagocyte progenitors suggest the multipotentiality of HL-60 stem cells. In order to clarify multilineage differentiation and commitment to single-lineage progenitors we analyzed HL-60 colonies formed in methylcellulose. In an HL-60 parent line with a relatively high eosinophil content (5.5%), 36% of the spontaneous colonies consisted partly or wholly of eosinophilic cells. After two rounds of subcloning in methylcellulose, two eosinophilic sublines and two neutrophilic sublines were established. These lines have been in continuous liquid culture for more than four months, and they show stable single-lineage differentiation. Purified biosynthetic GM-CSF, which stimulates normal CFU-GM and CFU-EO, induced monocytic differentiation but no eosinophilic differentiation in the neutrophilic sublines and no neutrophilic or monocytic differentiation in the eosinophilic sublines. These observations indicate that HL-60 stem cells are multipotent and capable of spontaneous commitment to single-lineage progenitors. The eosinophilic HL-60 sublines should facilitate studies on the production and function of human eosinophils and the single-lineage sublines will allow further analysis of leukemic cell differentiation and stem cell commitment.

Topics: Cell Differentiation; Cell Line; Clone Cells; Colony-Stimulating Factors; Eosinophils; Hematopoietic Stem Cells; Histocytochemistry; Humans; Leukemia, Myeloid, Acute; Methylcellulose; Recombinant Proteins

In the present study we utilized a semisolid culture system with feeder cells and enriched media to evaluate the growth of acute leukemia associated with the 4;11 chromosomal translocation. We compared growth of t(4;11) leukemia to typical acute nonlymphocytic leukemia (ANL) and acute lymphocytic leukemia (ALL). The two cases of t(4;11) leukemia tested exhibited the highest cloning efficiency of cells tested. The growth characteristics of t(4;11) leukemia were more similar to ANL than ALL.

Topics: Acute Disease; Adolescent; Adult; Bone Marrow; Cells, Cultured; Child; Child, Preschool; Chromosomes, Human, 4-5; Chromosomes, Human, 6-12 and X; Colony-Forming Units Assay; Female; Humans; Infant; Leukemia; Leukemia, Lymphoid; Leukemia, Myeloid, Acute; Male; Methylcellulose; Monocytes; Phenotype; Recurrence; Staining and Labeling; Translocation, Genetic

We report a micromethod for chromosome preparation from individual hematopoietic colonies cultured in methylcellulose. The entire process was carried out on poly-Lysine (PL)-coated slides. Individual colonies were transferred into 10 microliter of 0.075 M KCl and placed on PL-coated slides. After hypotonic treatment of the colony cells and their attachment to the slides, the cells were fixed by a three-step procedure as follows: addition of a 30% fixative (3:1 methanol:acetic acid) diluted with the hypotonic solution, addition of 20% ethanol, and subsequent immersion of the slides in a 100% fixative. The slides were flame dried and Giemsa stained. Q- and G-banding techniques also were used. These procedures provided analyzable chromosome preparations, even from colonies containing fewer than 50 cells.

Topics: Aged; Bone Marrow; Cell Separation; Cells, Cultured; Chromosome Banding; Chromosomes; Cytological Techniques; Female; Granulocytes; Hematopoietic Stem Cells; Humans; In Vitro Techniques; Leukemia, Myeloid, Acute; Male; Methylcellulose

Topics: Cells, Cultured; Humans; Leukemia, Myeloid, Acute; Methylcellulose; Microscopy, Electron; Neoplastic Stem Cells; Peroxidases; Stem Cells

To obtain permanent preparations for morphologic examination of hemopoietic cells cultured in methylcellulose medium, a new method designated as "the membrane filtration technique" has been devised. Permanent preparations of erythroid colonies, bursts and leukemic colonies, which have been grown mainly in methylcellulose medium, are illustrated in this paper. The stages of differentiation of cells within these colonies can be easily recognized by means of Wright-Giemsa staining.

Topics: Bone Marrow Cells; Cell Differentiation; Cells, Cultured; Culture Media; Erythropoiesis; Filtration; Hematopoietic Stem Cells; Humans; Leukemia, Myeloid, Acute; Methylcellulose; Plastics; Polymers

Topics: Colony-Forming Units Assay; Humans; Leukemia, Myeloid, Acute; Methylcellulose

We have developed simple methods for the rapid isolation and concentration of human leukemic colonies for cytologic evaluation. Colonies, grown in a medium containing methylcellulose, are gently washed from their culture dishes after reducing the viscosity of the colony layer. Colonies are washed and concentrated intact by mild centrifugation (10-20 g/5 min). Once isolated, colonies may enter any number of procedures for morphologic and cytokinetic analyses including exposure to radiolabeled compounds, cytocentrifugation, reaction with antibodies specific for certain cell surface markers, and fixation for routine light and electron microscopy. In addition, suspended or smeared colonies may be exposed to various substrates for the demonstration of endogenous enzymatic markers. Examples of possible preparations are presented.

Topics: Cell Separation; Cell Transformation, Neoplastic; Cells, Cultured; Clone Cells; Hematopoiesis; Humans; Interphase; Leukemia, Hairy Cell; Leukemia, Myeloid, Acute; Methylcellulose

A comparison was made between the agar and methylcellulose culture systems with respect to their ability to support the clonal growth of leukemic cells obtained from patients with acute myeloblastic leukemia, acute lymphoblastic leukemia, and chronic myelogenous leukemia in blastic crisis. The number of clusters and/or colonies formed and the morphology of the cells within them varied from patient to patient. Nevertheless, no significant difference between the two culture systems within given leukemic specimens was found. No significant differences were noted among three different conditioned media used as sources of colony-stimulating activity. Most of the cells within clusters and colonies were identified to be immature members of granulocyte-macrophage series or to be indistinguishable from the preculture leukemic blast cells by morphological and cell surface marker studies. Cells from myeloid crisis in chronic myelogenous leukemia grew well in the cultures, but cells from lymphoid crisis did not proliferate.

Topics: Adult; Agar; Aged; Antigens, Surface; Cell Division; Cells, Cultured; Female; Growth Substances; Humans; Leukemia; Leukemia, Myeloid, Acute; Male; Methylcellulose; Middle Aged; Rosette Formation

Topics: Antineoplastic Agents; Cell Division; Cell Survival; Clone Cells; Cytarabine; Doxorubicin; Drug Evaluation; Hematopoietic Stem Cells; Humans; Leukemia, Myeloid, Acute; Methylcellulose; Phytohemagglutinins

Topics: Cells, Cultured; Culture Media; Humans; Leukemia, Myeloid; Leukemia, Myeloid, Acute; Methylcellulose

Topics: Anemia, Aplastic; Bone Marrow Cells; Cell Count; Cell Division; Clone Cells; Humans; In Vitro Techniques; Kinetics; Leukemia, Lymphoid; Leukemia, Myeloid, Acute; Leukocytes; Methylcellulose

Topics: Aneuploidy; Cell Division; Cells, Cultured; Chromosome Aberrations; Culture Media; Humans; Karyotyping; Leukemia, Myeloid; Leukemia, Myeloid, Acute; Lymphocytes; Methylcellulose

Topics: Bone Marrow; Bone Marrow Cells; Cell Line; Culture Media; Culture Techniques; Embryo, Mammalian; Humans; Kidney; Leukemia, Lymphoid; Leukemia, Myeloid; Leukemia, Myeloid, Acute; Leukocytes; Methylcellulose; Monocytes