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R Taetle

Publications and source records attributed to R Taetle.

At least 91 records · Page 5Linked to original sources
PubMed1986

CSF-responsive bone marrow cells in liquid culture: characterization and screening applications.

In a previous study, colony-stimulating factor (CSF) activity assayed in colony culture correlated closely with 3HTdR uptake by human marrow cells depleted of adherent cells. To use this assay for screening media for CSF and immunotoxins for marrow toxicity, cells growing in liquid culture were compared to conventional granulocyte/macrophage (CFU-gm) colony assays. CSF dose-response relationships for liquid and colony-forming assays were nearly identical. 3HTdR uptake by nonadherent marrow cells was CSF dose-related, and there was a linear relationship between number of cells cultured and 3HTdR uptake. Ricin cytotoxicity curves for liquid cultures and CFU-gm were identical on day 7 but showed some disparity with day 14 cultures. Results with all cultures showed 3HTdR uptake to be most closely correlated with CFU-gm colony, rather than cluster, growth. Myeloid cell differentiation in liquid culture was similar to colony cultures, producing mixtures of granulocytes, macrophages and eosinophils. By combining cell and differential counts, production of various myeloid cells could be quantitated. Cytotoxicity of anti-Ia for CFU-gm and liquid culture cells was compared and the majority of both cell populations expressed Ia-like antigens. Simultaneous staining for surface antigens and DNA content was used to characterize proliferating marrow cells, and the vast majority of cells expressed myeloid markers. Transferrin receptors were displayed by cells in S/G2/M and appeared after CSF stimulation on G0/G1 cells. We conclude liquid cultures can be used to screen conditioned media for human CSF and to screen for cytotoxicity to normal myeloid precursor cells. Behavior of CSF-responsive cells in liquid culture appears most closely related to that of CFU-gm colony-forming cells, and characterization of CSF-stimulated cells allows quantitative as well as qualitative estimates of myeloid cell production.

Antigens, Surface↗
PubMed1986

Induction of colony-stimulating factor response in myeloid leukaemia cell lines.

Untreated, late passage HL60 promyelocytic and KG1 myeloblastic leukaemia cells did not increase proliferation with placenta or Mo T cell conditioned medium containing colony-stimulating factor (CSF) nor with partially purified, recombinant granulocyte/macrophage (GM)-CSF. However, after induction with DMSO or 1,25-dihydroxy-vitamin D3, HL60 cells showed dose-dependent increases in proliferation with crude and purified CSFs. CSF responses and macrophage differentiation were induced in KG1 cells by treatment with tetradecanoylphorbol-acetate (TPA). When cells were exposed to inducing agents for varying periods, washed and exposed to CSF, proliferative responses were related to time of exposure. Cells exposed for 1-4 d showed post-induction CSF-induced proliferation, but cells induced for 5-6 d were inhibited by CSF. Induction of CSF response appeared linked to differentiation, since KG1 cells differentiated with TPA and developed CSF-induced proliferative responses, but showed no differentiation or CSF induced proliferation after treatment with vitamin D3. When HL60 cells were continuously exposed to DMSO or vitamin D3, overall cell production was increased by placenta conditioned medium, but cultures still became senescent and died after several weeks. Cells continuously cultured with DMSO were predominantly macrophages, indicating lineages of DMSO-induced differentiation were modified by continuous culture or the presence of CSF. After treatment with chemical inducers, proliferation of myeloid leukaemia lines is stimulated by CSF, providing a model for post-deterministic regulation of normal and malignant myeloid cell production.

Calcitriol↗
PubMed1986

Transferrin modulation of colony stimulating factor elaboration by adherent blood and bone marrow cells.

When added to cultured normal, adherent blood and marrow cells at concentrations of 25-100 micrograms/ml (3 X 10(-7) to 1.3 X 10(-6) M), human transferrin enhanced colony-stimulating factor (CSF) elaboration. Fe saturated and relatively unsaturated Tf were equally effective in increasing CSF release, but soluble ferric nitriloacetate was ineffective. Dose-dependent increases in CSF release by adherent blood and marrow cells occurred in serum-free media and the continuous presence of Tf was necessary for this effect. Using a monoclonal anti-Tf receptor antibody, normal blood mononuclear cells contained no detectable Tf receptor positive cells. However, after 5 d culture in serum-free medium, Tf receptor positive cells were identified among normal adherent blood cells, and the per cent receptor positive cells increased with Tf concentration. We conclude Tf modulates CSF production from normal, adherent blood and marrow cells in vitro. These findings indicate a possible role for Tf in intramedullary regulation of normal granulopoiesis.

Acute Disease↗
PubMed1986

Mechanisms of growth inhibition by anti-transferrin receptor monoclonal antibodies.

In previous studies, an immunoglobulin A, anti-transferrin receptor antibody (42/6) inhibited growth of a variety of normal and malignant human hemopoietic cells. To determine its mechanism of growth inhibition, we compared effects of 42/6 and B3/25, an immunoglobulin G anti-transferrin receptor antibody which does not inhibit lymphocyte growth, on transferrin (TF) binding and uptake. As in previous studies, affinity constants of TF and anti-TF receptor antibodies for human TF receptors at 4 degrees C were similar, but the number of calculated binding sites was higher for the antibodies. Antibody B3/25 did not inhibit TF binding at either 4 degrees C or 37 degrees C. At 4 degrees C, antibody 42/6 inhibited TF binding to normal, mitogen-stimulated mononuclear cells. However, TF did not inhibit 42/6 binding, suggesting 42/6 inhibited TF binding by noncompetitive, possibly steric, mechanisms. When cells were simultaneously exposed to labeled TF and unlabeled anti-TF receptor antibodies at 37 degrees C, 42/6 inhibited TF binding only slightly. Initial uptake of antibodies and TF at 37 degrees C was rapid, but when mononuclear cells or HL60 cells were cultured with either 42/6 or B3/25 for 2 days, TF binding and immunoreactive TF receptor sites decreased. However, TF bound to cells cultured with B3/25 continued to enter the cell, whereas cells cultured with 42/6 would no longer take up bound TF. Studies using HL60 cells grown with soluble iron in lieu of TF showed that changes in TF binding sites and TF uptake were not secondary to growth inhibition. We conclude that incubation with both inhibitory (42/6) and noninhibitory (B3/25) anti-TF receptor antibodies results in decreased TF binding sites. However, exposure to 42/6 also inhibits TF uptake and causes growth inhibition by iron deprivation. Monoclonal antibodies to receptors transporting critical nutrient molecules, such as iron, may inhibit cell growth by blocking ligand access to the cell's interior.

Animals↗
PubMed1985

Heterogeneity of Ia antigen expression by proliferating nonlymphocytic leukemia blast cells.

In vitro systems were used to detect Ia-like antigens on proliferating normal myeloid and acute nonlymphocytic leukemia (ANLL) blast cells. Incubation of normal bone marrow cells with a monoclonal anti-Ia antibody and complement resulted in toxicity for both granulocyte/macrophage progenitors (CFU-GM) (toxicity 79%-100%) and cells proliferating in liquid culture in response to placenta-conditioned medium colony-stimulating factor (CSF) or medium conditioned by normal, phytohemagglutinin (PHA)-stimulated mononuclear cells. In contrast, effects of anti-Ia antibody and complement on blast colony-forming cells and 3H-TdR incorporation in liquid culture from eight patients with ANLL were variable. Colony growth with CSF after treatment was 0% to 91% of control growth and did not correlate with display of Ia-like antigens. Survival of ANLL cells growing in liquid cultures was even more variable after anti-Ia+ complement treatment (28%-227% of control). The presence of Ia-like antigens did not distinguish ANLL cells responding to PHA-conditioned medium from those responding to CSF in either colony or liquid culture. Dose-response curves for ANLL cells in liquid culture were similar before and after treatment with anti-Ia+ complement. In contrast to normal myeloid precursor cells, which show uniform display of Ia-like antigens, display of Ia antigen by proliferating leukemia cells is highly variable from patient to patient. Anti-Ia reagents such as this one would not be effective in treating ANLL marrow for autologous transplantation.

Acute Disease↗
PubMed1985

Transferrin receptor regulation is coupled to intracellular ferritin in proliferating and differentiating HL60 leukemia cells.

Cultured myeloid leukemia cells display transferrin receptors but decrease receptor display after differentiation induction or accumulation of intracellular iron. To determine whether regulation of transferrin receptors and ferritin were linked under these disparate conditions, serum-free and fetal bovine serum (FBS) cultures of HL60 promyelocytic leukemia cells were used to investigate relationships between transferrin receptor display and intracellular ferritin. Using 125I-transferrin binding and immunofluorescence staining for transferrin receptors, HL60 cells cultured in serum-free, transferrin-free medium expressed fewer transferrin receptors and contained increased ferritin when compared to cells cultured with FBS or transferrin supplemented, serum-free medium. When placed in medium containing transferrin, cells previously grown in transferrin-free medium rapidly re-expressed transferrin receptors and decreased their ferritin content. HL60 cells induced to differentiate into granulocytes or macrophages also decreased transferrin receptor display and increased their ferritin content. Transferrin receptor display and ferritin content in both proliferating and differentiating myeloid leukemia cells are inversely related and their regulation is closely linked. Regulation of transferrin receptor display and ferritin synthesis may be important events regulating myeloid cell growth and differentiation.

Cell Division↗
PubMed1985

Glycophorin A on normal and leukemia cells detected by monoclonal antibodies, including a new monoclonal antibody reactive with glycophorins A and B.

A new hemagglutinating monoclonal antibody, MoAb31, detected glycophorins A and B in Western blots. Results with enzyme-modified erythrocytes indicated the MoAb31 determinants were sialic acid dependent, and resided on glycophorin A on the trypsin-resistant, ficin-sensitive segment, and on glycophorin B on the ficin-sensitive segment. Another new monoclonal antibody, MoAb36, detected the Wrb antigen, located on the non-glycosylated segment of glycophorin A near its insertion into the lipid bilayer. Immunofluorescent staining of normal hematopoietic and leukemia cells with these and other monoclonal antibodies to glycophorin A demonstrated glycophorin A on erythroid cells only. Cytofluorograph analysis showed the majority of cells of the erythroleukemia cell lines K562 and HEL expressed glycophorin A, as indicated by reactivity with the monoclonal glycophorin A antibodies R10, R18, 6A7 and 10F7. However, reactivity with monoclonal antibodies to glycosylated determinants (MoAb31 and R1.3) and to the non-glycosylated segment near the membrane insertion (MoAb36, and R7.1) was reduced or absent. Expression of "missing" glycophorin A antigens on K562 and HEL could not be induced using a variety of chemical and biologically active modifiers. We conclude that glycophorin A of erythroleukemia cell lines K562 and HEL differs from glycophorin A at the surface of normal, mature erythrocytes with respect to reactivity with monoclonal glycophorin A antibodies.

Animals↗
PubMed1985

In vitro drug testing using hemopoietic cells: goals and limitations.

In vitro drug sensitivity is one of many biologic variables which may predict in vivo drug response. Even if in vitro assays provide relevant data, for some tumors, variable levels of stem-cell origin, differentiation, tumor heterogeneity, or self renewal may be more important than cytotoxicity to proliferating cells. Although ANLL has been used here frequently as a model, it may not be the most appropriate tumor for study. Unlike many cancers, in ANLL, primary drug resistance is unusual, and in relapse, secondary drug resistance is usually incomplete. It has been suggested that in vitro drug sensitivity predicts remissions for patients who do not die of infection or remain aplastic during induction therapy. However, for the majority of patients, this argument acknowledges the overriding importance of biologic variables other than in vitro drug cytotoxicity. For rapidly growing tumors, such as Burkitt's lymphoma, rapid emergence of drug resistance related to disease burden may be the most important response determinant. Perhaps in other tumors, in vitro drug sensitivity will be an independent variable of overriding importance. To determine the role of in vitro drug testing, trials examining in vitro drug sensitivity must meet stringent criteria. The assays should use well-defined and reproducible cultures and drug exposures. The trials must be large enough, contain homogenously treated patients, and use carefully defined response and survival endpoints. Decision rules derived from such trials must be further tested by prospective evaluation. Investigators conducting these trials must be prepared to search for important in vitro results reflecting tumor biology and to analyze in vitro drug sensitivity as only one continuous variable determining in vivo responses. Such trials will be difficult to conduct and expensive. In the final analysis, in vitro assays may find their most important roles as preclinical drug screens and models for in vitro drug resistance. Further insights into molecular genetics of malignant transformation and drug resistance may make such assays obsolete, but for the present, they provide important insights into tumor variability and mechanisms of drug response.

Animals↗
PubMed1985

Role of transferrin, Fe, and transferrin receptors in myeloid leukemia cell growth. Studies with an antitransferrin receptor monoclonal antibody.

In previous studies, antitransferrin receptor antibody 42/6 inhibited growth of normal granulocyte/macrophage progenitors and some malignant myeloid cells. In these studies, leukemia cell lines cultured without serum and fresh leukemia cells were used to investigate the roles of Fe, transferrin receptors, and transferrin in leukemia cell growth, and mechanisms of 42/6 inhibition and resistance. HL60 and KG-1 leukemia cells grown in serum-free medium were inhibited by 42/6. In contrast to results in fetal calf serum (FCS), soluble Fe (ferric nitriloacetate) reversed 42/6 growth inhibition of serum-free HL60 cells. When HL60 cells were adapted for growth in serum-free, transferrin-free medium, they became refractory to 42/6 growth inhibition. By using radiolabeled transferrin and 42/6, HL60 cells cultured in FCS and transferrin displayed similar quantities of transferrin receptors (29,000-30,000/cell) and similar Kd's (3.8-4.9 X 10(-9) M). Cells grown in transferrin-free medium showed a similar Kd (3.1 X 10(-9) M), but fewer transferrin binding sites (5,000/cell). Transferrin-independent cells contained a log higher concentration of intracellular ferritin. For both FCS and serum-free HL60 cells, calculated affinities for 42/6 were lower (5.7-10.0 X 10(-9) M), but the number of binding sites was three- to fourfold higher. To investigate further the relationship between receptor display and antibody inhibition in proliferating normal and malignant myeloid cells, simultaneous immunofluorescence was used to determine the cell cycle status of transferrin receptor-positive cells. Malignant cells in S + G2/M displayed approximately 50% of the amount of transferrin receptors detected in normal dividing colony-stimulating factor-stimulated marrow cells. Receptor display by dividing cells from two patients with acute nonlymphocytic leukemia was variable. When HL60 cells were exposed to dimethyl sulfoxide, transferrin receptor display decreased, and 42/6 growth inhibition was abrogated or greatly diminished. The presence of 42/6 did not prevent dimethyl sulfoxide-induced HL60 differentiation in serum-containing or serum-free cultures. We conclude that human leukemia cells require Fe for growth and that 42/6 inhibits transferrin-dependent cells by Fe deprivation. Some dividing normal and differentiating malignant cells display reduced transferrin receptors, and can also escape antibody inhibition. The increased ferritin levels and decreased transferrin receptors in transferrin-independent HL60 cells confirm the inverse relationship between cell ferritin content and transferrin receptor display. These studies indicate a critical role for Fe in leukemia cell growth and possible roles in cellular differentiation.

Antibodies, Monoclonal↗
PubMed1985

Modulation of the activity of PALA by dipyridamole.

PALA is thought to inhibit an early step in de novo pyrimidine synthesis, causing depletion of intracellular pyrimidine nucleotides. Dipyridamole, a nucleoside transport inhibitor which can block restoration of nucleotide levels via the salvage pathway, was tested for its ability to augment the cytotoxicity of PALA against normal and malignant human cells in vitro. At the clinically relevant concentration of 1 microM, dipyridamole increased the cytotoxicity of PALA against a melanoma, a colon carcinoma, a promyelocytic leukemia (HL-60), and normal marrow (CFU-GM) in clonogenic assays. Dipyridamole produced 50% inhibition of uridine uptake in these cells at concentrations of less than 0.1 microM and reduced the LD50 of PALA by approximately 50% in mice. These results indicate that dipyridamole can markedly potentiate the activity of PALA in vitro and in vivo.

Animals↗
PubMed1985

Preclinical studies on the use of selective antibody-ricin conjugates in autologous bone marrow transplantation.

Whole-ricin immunoconjugates were synthesized with the pan-T cell antibodies T101 and 3A1 and assayed in the presence of 0.1 mol/L lactose. Their toxicity for cell lines, peripheral blood T lymphocytes, and normal bone marrow progenitors was compared with that of whole ricin. In the presence of 0.1 mol/L lactose, normal cells and cell lines exhibited the following sensitivities to ricin: 8392 (human malignant B cell line) less than E rosette-positive lymphocytes less than bone marrow progenitors less than 8402 (human T ALL) less than CEM (human T ALL). Ricin sensitivities correlated with ricin binding as determined by immunofluorescence. In the presence of lactose, peripheral blood T cells were resistant to 0.1 nmol/L ricin, but a similar concentration of T101-ricin inhibited normal and malignant T colony formation by greater than 98%. 3A1-ricin was slightly less effective. At a conjugate concentration of 0.1 nmol/L, bone marrow progenitor colony formation was inhibited by 30% or less; T101-positive cells were at least tenfold more sensitive than normal progenitors. When mixtures of 10% CEM cells and marrow cells were incubated with T101-ricin, 95% of CEM colonies were killed, and 96% of marrow granulocyte/ macrophage progenitors survived. Some free ricin was released from immunotoxin-treated cells, producing minimal inhibition of protein synthesis or cell growth. We conclude that (a) normal blood cells and malignant cell lines exhibit varying degrees of ricin sensitivity in the presence of lactose; (b) T101-ricin is at least tenfold more toxic to T lymphocytes than to bone marrow progenitor cells and is effective in mixtures of normal and malignant cells; and (c) treatment of infiltrated marrow with anti-T cell immunotoxins should safely remove target T cells without excessively damaging normal progenitors or producing excessive free ricin. Anti-T cell, whole-ricin immunotoxins merit trials for autologous transplantation.

Antibodies, Monoclonal↗
PubMed1984

Further studies on mechanisms of abnormal prostaglandin response by chronic myelogenous leukaemia granulocyte/macrophage progenitors.

Prostaglandins of the E series (PGE) have varying effects in vitro on normal granulocyte/macrophage (CFU-GM) progenitors. When added directly to cultures, PGE inhibits growth of normal 7 and 14 day bone marrow CFU-GM in a dose-dependent manner, while CML CFU-GM are refractory to PGE inhibition. The plant diterpene forskalin, a potent activator of intracellular cyclic AMP, inhibited normal and CML CFU-GM, indicating that the response of CML cells to increased intracellular cyclic AMP is normal. Low dose forskalin, which potentiates activators of adenyl cyclase, showed additive effects with PGE on normal CFU-GM cells, however, showed no additive effects of PGE and forskalin, suggesting that PGE failed to activate adenyl cyclase. Normal CFU-GM incubated with PGE for two hours showed a significant increase in CFU-GM growth, and removal of adherent cells prior to exposure to PGE abrogated this effect. CML cells did not respond to a 2-h exposure to PGE, and removal of adherent cells from these cultures had no effect. Normal and CML CFU-GM showed dose-dependent increases in proliferation in the presence of PGF2. These studies confirm that CML CFC-GM are refractory to inhibition by PGE, and show that these cells respond normally to increased levels of intracellular cyclic AMP. Response of CML cells to PGF2 alpha is normal, and conversion of PGE to PGF could result in increased granulocyte progenitor proliferation.

Adenylyl Cyclases↗
PubMed1983

Effects of anti-transferrin receptor antibodies on growth of normal and malignant myeloid cells.

The effects of three monoclonal antibodies (B3/25, 43/31, and 42/6) reactive with human transferrin (Tf) receptors on growth of normal and malignant myeloid cells were examined using in vitro culture techniques. When added directly to cultures, all three antibodies caused dose-dependent inhibition of normal granulocyte/macrophage progenitor (CFU-GM) growth. Monoclonal antibody 42/6 was by far the most potent of the three, with an ID50 of less than 5 micrograms/ml. Identical effects were seen on CFU-GM from three patients with chronic myelogenous leukemia. Growth of colonies from two myeloid leukemia cells lines (KG-I, HL60) was also inhibited by all three antibodies, and these cells were generally more sensitive than normal CFU-GM. Blast colony-forming cells from three patients with acute non-lymphocytic leukemia were relatively resistant to the antibodies, and CFU-GM from a patient with myeloid metaplasia were resistant (ID50 greater than 50 micrograms/ml) to 42/6. In liquid culture, growth of the leukemic cell lines was inhibited by saturating concentrations of the three antibodies, although in both liquid and colony culture recovery was seen even after exposure to antibody for periods of up to 72 h. Analysis of the cell-cycle status of these cells showed that the antibodies did not cause accumulation of cells in any particular phase of the cell cycle. Addition to cultures of large quantities of human Tf failed to reverse the inhibitory effects of the antibodies. Competitive binding studies on the leukemia cell lines showed that only 42/6 inhibited binding of Tf to its receptor, although all three antibodies inhibited cell growth. Addition of Fe chelate (as ferric nitriloacetic acid, FeNTA) failed to reverse the inhibitory effects of the antibodies on CFU-GM and HL60 cells, but had variable effects on KG-I cell growth. FeNTA fully reversed inhibitory effects of 42/6 on KG-I cells. We conclude that monoclonal antibodies to Tf receptors can inhibit growth of both normal and malignant myeloid cells. Overall, no selectivity for malignant vs normal cells is apparent, although malignant cells from one individual were more sensitive to colony inhibition by 43/31 monoclonal antibody than normal CFU-GM.

Animals↗
PubMed1983

Failure of low-dose, total-body irradiation to augment combination chemotherapy in extensive-stage small cell carcinoma of the lung.

In a pilot study, 21 consecutive eligible patients with extensive-stage small cell carcinoma of the lung were scheduled for treatment with combination chemotherapy followed by total-body irradiation (TBI), prophylactic cranial irradiation, and consolidative chemotherapy. Induction chemotherapy consisted of VP16-213, vincristine, cyclophosphamide, and doxorubicin (VOCA). TBI was given as 100 rads in 10 fractions over 2 wk. Consolidation chemotherapy consisted of cyclophosphamide, methotrexate, and hexamethylmelamine (CMH). VOCA chemotherapy was well tolerated, with a 79% response rate in 19 evaluable patients. TBI was successfully given after four cycles of VOCA without excessive morbidity in 11 patients, although subsequent CMH chemotherapy in 8 patients has required dose reductions and some delays in therapy. Unfortunately, TBI did not increase the degree of response, and 2 patients relapsed during this therapy. Median survival in this study was 40-44 wk. One patient has survived 78 wk and remains in remission. TBI can be safely given following induction chemotherapy in extensive-stage small cell carcinoma of the lung, but it does not appear to add to the therapeutic benefit of combination chemotherapy alone.

Aged↗
PubMed1983

Specific toxicity of 2-chlorodeoxyadenosine toward resting and proliferating human lymphocytes.

2-Chlorodeoxyadenosine (CdA), an adenosine-deaminase-resistant purine deoxynucleoside, is markedly toxic toward human T-lymphoblastoid cell lines in vitro and is an effective agent against L1210 leukemia in vivo. The present studies have examined the toxicity, and in some cases, metabolism, of CdA in (1) multiple established human cell lines of varying phenotype, (2) leukemia and lymphoma cells taken directly from patients, (3) normal bone marrow cells, and (4) normal peripheral blood lymphocytes. Nanomolar concentrations of CdA blocked the proliferation of lymphoblastoid cell lines with a high ratio of deoxycytidine kinase to deoxynucleotidase. The drug had virtually no effect on the growth of cell lines derived from solid tissues. The CdA inhibited the spontaneous uptake of tritiated thymidine by many T and non-T, non-B acute lymphoblastic leukemia cell specimens at concentrations less than or equal to 5 nM. The same concentrations did not impair either thymidine uptake or granulocyte-monocyte colony formation by normal bone marrow cells. In common with deoxyadenosine, but unlike several other agents affecting purine and purine metabolism, CdA was lethal to resting normal T lymphocytes and to slowly dividing malignant T cells. In both resting and proliferating lymphocytes, the CdA was phosphorylated by deoxycytidine kinase and entered a rapidly turning over nucleotide pool. Dividing lymphocytes also incorporated abundant CdA into DNA. The selective toxicity of CdA toward both dividing and resting lymphocytes may render the drug useful as an immunosuppressive or antileukemic agent.

Cell Division↗
PubMed1983

Response of human myeloid leukemia cells to various sources of colony-stimulating activity and phytohemagglutinin-conditioned medium.

The response of human myeloid leukemia cells to various sources of colony-stimulating activity (CSA) and media conditioned by phytohemagglutinin-stimulated mononuclear cells (PHA-LCM) was investigated in liquid and colony culture. PHA-LCM, placenta-conditioned medium, GCT cell line-conditioned medium, leukocyte-conditioned medium, and partially purified CSA for human and murine cells were tested for ability to support growth of granulocyte-macrophage colonies from adherent cell-depleted human bone marrow. This activity was correlated with ability to support leukemia colony growth in methylcellulose, and [3H]thymidine incorporation in liquid culture by normal bone marrow cells, leukemia cells, and the KG-1 myeloid leukemia cell line. For normal cells, growth and liquid culture responses were highly correlated for various sources of CSA (r = 0.92), and addition of data using PHA-LCM changed results only slightly (r = 0.89). [3H]thymidine incorporation by leukemia cells from patients without a prior history of a myeloproliferative disorder was also highly correlated with normal CSA (r = 0.97) for sources other than PHA-LCM. Responses of leukemia blasts and KG-1 cells in liquid culture to PHA-LCM appeared in excess of its CSA for normal cells. Colony growth by leukemia cells was not clearly correlated with either liquid culture activity for leukemia cells or CSA for normal cells. PHA-LCM was also not statistically superior to placenta-conditioned medium as stimulus for leukemia colony growth, but was superior to placenta-conditioned medium for some patients. Differentiation in culture did not appear to depend on CSA source. We conclude that normal myeloid cells respond to CSA in a highly correlated fashion in both colony and liquid cultures. The majority of myeloid leukemia cells respond to either PHA-LCM or CSA, but the ability of PHA-LCM to support leukemia cell growth is greater than its CSA content. The possibility exists that overlapping populations responsive to CSA and to PHA-LCM are present simultaneously in patients with myeloid leukemia.

Bone Marrow↗
PubMed1983

In vitro sensitivity to steroid hormones and cytotoxic agents of normal and malignant lymphocyte colony-forming cells.

In vitro assays were used to assess the sensitivity of normal T-cells and malignant, chronic lymphocytic leukemia (CLL) lymphocyte colony-forming cells (CFC) to a panel of cytotoxic drugs and steroid hormones. Normal T-CFC were remarkably resistant to hydrocortisone, progesterone, estradiol, and testosterone at concentrations less than or equal to 10(-5) M. Variable inhibition was seen at concentrations of 10(-4) M, and prior exposure to phytohemagglutinin increased sensitivity only to sex steroid hormones. In contrast to T-CFC, which showed little variation in patterns of steroid hormone inhibition in vitro, CLL-CFC from individual patients displayed widely varying sensitivity to all hormones tested; 50% inhibitory dose varied by as much as 2 logs. T-CFC were fairly resistant to a 1-hr exposure to achievable concentrations of 1-beta-D-arabinofuranosyl-cytosine, 5-fluorouracil, chlorambucil, melphalan, cisplatin, methotrexate, Adriamycin, and bleomycin. Prior exposure to phytohemagglutinin resulted in increased sensitivity only to low concentrations of Adriamycin, a phenomenon that appeared related to prior or concurrent lectin exposure and not to changes in cell cycle status. CLL-CFC showed variable sensitivity to Adriamycin and cisplatin, and concurrent exposure to lectin and Adriamycin did not increase sensitivity to that drug. CLL cells displayed much greater sensitivity to a 1-hr exposure to antimetabolites and bleomycin than to continuous exposure to the same drugs. In contrast to normal T-CFC, CLL-CFC exposed to methotrexate were not "rescued" by subsequent culture in media and fetal bovine serum. Incubation of T-CFC or CLL-CFC with melphalan and a source of protein (fetal bovine serum or bovine serum albumin) resulted in decreased cell kill. Differences in in vitro sensitivity of normal and malignant lymphocyte CFC to steroids and cytotoxic agents can be demonstrated using these culture systems. CLL-CFC showed variable sensitivity to hydrocortisone, and much greater sensitivity to antimetabolites than normal T-CFC. Differences in conditions of drug exposure, such as concurrent exposure to lectin or inclusion of protein, may alter the in vitro sensitivity of lymphocyte CFC to some drugs.

Cell Survival↗