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M Andreeff

Publications and source records attributed to M Andreeff.

At least 199 records · Page 11Linked to original sources
PubMed1992

Effects of extracellular matrix on the response of endothelial cells to radiation in vitro.

The study demonstrates that the sensitivity of endothelial cells to irradiation in vitro is significantly affected by the microenvironmental conditions under which the experiment is carried out. When irradiated plateau phase bovine aortic endothelial cells were assayed for colony formation on top of uncoated plastic of standard culture dishes, the dose survival curves showed Do values of [mean (S.D.)] 107 (6) cGy and Dq of 63 (28) cGy (calculated according to the single-hit multitarget model). When assayed in dishes precoated with the autologous natural basement membrane-like extracellular matrix (BAEC/ECM) the curves showed a similar Do [106 (2) cGy], but the Dq was 194 (8) cGy (P less than 0.05), indicating that components of natural ECM confer in endothelial cells an improved capacity to repair radiation lesions and to restore the clonogenic capacity. However, when the natural but biologically unrelated HR9-bFGF/ECM was used, a decreased repair capacity was noted with Dq of 156 (30) cGy (P less than 0.05 compared with BAEC/ECM). The data demonstrate the high specificity of the repair function to interactions with autologous matrix components, and emphasise the need to select relevant experimental conditions when parameters of the radiation response in vitro are used to predict the response in vivo.

Animals↗
PubMed1992

Comparison of in vivo and in vitro effects of granulocyte-macrophage colony-stimulating factor (GM-CSF) in patients with acute myeloid leukemia.

We studied the in vitro effects of granulocyte-macrophage colony-stimulating factor (GM-CSF) in 13 patients with acute myeloid leukemia (AML) and one patient with refractory anemia with excess of blasts in transformation using the AML blast (AML colony-forming units, AML-CFU) and mixed (granulocyte erythrocyte macrophage megakaryocyte colony-forming units, CFU-GEMM) colony culture assays. In parallel, these patients received GM-CSF s.c. at 125 micrograms/m2/day, or in escalated doses starting with 10 micrograms/m2/day for a week or until circulating blast counts reached 50 x 10(9)/liter, in an effort to sensitize leukemic blasts to cell-cycle-specific agents. Results of in vivo GM-CSF treatment were correlated with those of in vitro assays. In 9 of 12 patients (75%), GM-CSF treatment increased peripheral blood blast counts (in vivo effect). GM-CSF also stimulated in vitro AML blast colony proliferation in these nine patients and increased the S+G2M phases of the cell cycle in five out of five of these patients' samples. Two of three patients in whom an in vivo response could not be demonstrated also failed to have a detectable in vitro response. These observations suggest that the AML blast colony culture assay may be useful in predicting the response of AML to cytokine therapy. Finally, GM-CSF stimulated granulocyte-macrophage (granulocyte-macrophage colony-forming units, CFU-GM) and erythroid (erythroid burst-forming units, BFU-E) colony proliferation in 14 and 11 patients, respectively, including the 3 individuals who demonstrated no clinical effect on blast counts. It is, therefore, possible that GM-CSF may be used to stimulate proliferation of progenitors that differentiate into mature granulocyte, monocyte-macrophage, and erythroid cells.

Acute Disease↗
PubMed1992

Proliferation of human hematopoietic progenitors in long-term bone marrow cultures in gas-permeable plastic bags is enhanced by colony-stimulating factors.

We compared the recovery of human hematopoietic progenitors in long-term bone marrow culture (LTBMC) initiated in tissue culture (TC) flasks to that in "Lifecell" bags, which are gas-permeable plastic bags in which feeder-layer cells cannot adhere. Our results showed that granulocyte-macrophage colony-forming unit (CFU-GM) and erythroid burst-forming unit (BFU-E) cumulative recovery in cultures from normal donor marrow, expressed as a percent of the initial inoculum, was not statistically different in the two culture systems up to week 8, when the cultures were terminated: 31.5 +/- 19 (flask) vs 30 +/- 14 (bag) and 15.5 +/- 12 (flask) vs 11.5 +/- 8 (bag), respectively. The effects of weekly addition of recombinant human (r-hu)-interleukin 1 (IL1) and r-hu-interleukin 3 (IL3) were then studied, alone and combined, at two different concentrations. Addition of IL1, either alone or combined with IL3, in LTBMC established in flasks induced an increase of hematopoietic progenitors for the first week, but BFU-E and CFU-GM were no longer detectable at weeks 4 and 6, respectively. Analysis of adherent layer cells showed a decreased cellularity, no adipogenesis, and early disappearance of bone marrow (BM) progenitors, whereas the cycling rate of myeloid precursors, by cytosine arabinoside (Ara-C) suicide assay, was similar to that of untreated cultures. Conversely, IL3 alone (5 ng/ml) resulted in 3.6- and 5.4-fold peak increases for CFU-GM and BFU-E, respectively, at week 1 (adherent plus nonadherent cells), and the recovery of BM cells was still higher than that of control flasks at week 8. By comparison, stimulation with colony-stimulating factors (CSFs) of BM cells grown in bags never affected the longevity of the culture. Addition of IL3 (5 ng/ml) induced a higher recovery of total cells, CFU-GM (range: 1.6- to 15-fold peak increase during the culture), and BFU-E (1.2- to 3-fold) compared to the untreated controls. Bags treated with IL1 alone demonstrated only transient beneficial effects, and the number of hematopoietic precursors fell below the level of control bags during the culture. IL1 and IL3 induced 1.8- and 5.3-fold peak increases in BFU-E and CFU-GM at weeks 1 and 4, respectively. Simultaneous flow cytometric analysis of CD34+/CD33+ cells and DNA content showed increased numbers and proliferation of the committed BM progenitors when CSFs were added to the bag.(ABSTRACT TRUNCATED AT 400 WORDS)

Bone Marrow Cells↗
PubMed1991

Interleukin-4 inhibits growth of multiple myelomas by suppressing interleukin-6 expression.

Unfractionated bone marrow (BM) cells obtained from patients with multiple myeloma (MM) exhibit high levels of interleukin (IL)-6. Secretion of IL-6 by these cells as well as spontaneous plasma cell proliferation can be abrogated by neutralizing anti-IL-6 monoclonal antibody (MoAb). Treatment of BM cells with recombinant human (rh)IL-4 at doses of 50 to 250 U/mL blocked endogenous IL-6 synthesis in a dose-dependent fashion and was associated with significant reduction of plasma cell growth that could be reversed by exogenous rhIL-6. Enrichment of BM cells from MM patients for plasma cells and adherent cells and analysis of IL-6 mRNA in these subpopulations by means of quantitative polymerase chain reaction (PCR) showed that adherent BM cells accounted for most of the synthesis of IL-6 transcripts, whereas plasma cells displayed negligible levels of IL-6 mRNA only. These results suggest therapeutic evaluation of rhIL-4 in patients with plasma cell neoplasms.

Base Sequence↗
PubMed1991

Differentiation therapy of acute promyelocytic leukemia with tretinoin (all-trans-retinoic acid).

BACKGROUND AND METHODS: Patients with acute promyelocytic leukemia have a characteristic (15;17) translocation, with a breakpoint on chromosome 17 in the region of the retinoic acid receptor-alpha (RAR-alpha). Since this receptor has been shown to be involved with growth and differentiation of myeloid cells in vitro, and since recent clinical studies have reported that tretinoin (all-trans-retinoic acid) induces complete remission in patients with acute promyelocytic leukemia we studied the effects of tretinoin on cellular maturation and molecular abnormalities in patients undergoing the induction of remission with this agent. RESULTS: Eleven patients with acute promyelocytic leukemia were treated with tretinoin administered orally at a dose of 45 mg per square meter of body-surface area per day. Nine of the 11 patients entered complete remission. In two patients, complete remission was preceded by striking leukocytosis that then resolved despite continued drug treatment. Serial studies of cellular morphologic features, cell-surface immunophenotypic analysis, and fluorescence in situ hybridization with a chromosome 17 probe revealed that clinical response was associated with maturation of the leukemic clone. All patients who responded to treatment who were tested by Northern blot analysis had expression of aberrant RAR-alpha. As patients entered complete remission, the expression of the abnormal RAR-alpha message decreased markedly; however, it was still detectable in several patients after complete morphologic and cytogenetic remission had been achieved. CONCLUSIONS: Tretinoin is a safe and highly effective agent for inducing complete remission in patients with acute promyelocytic leukemia. Clinical response to this agent is associated with leukemic-cell differentiation and is linked to the expression of an aberrant RAR-alpha nuclear receptor. Molecular detection of the aberrant receptor may serve as a useful marker for residual leukemia in patients with this disease.

Administration, Oral↗
PubMed1991

Results of a randomized trial comparing idarubicin and cytosine arabinoside with daunorubicin and cytosine arabinoside in adult patients with newly diagnosed acute myelogenous leukemia.

4'-Demethoxydaunorubicin (idarubicin [IDR]) is a new anthracycline that differs from its parent compound by the deletion of a methoxy group at position 4 of the chromophore ring. This minor structural modification results in a more lipophilic compound with a unique metabolite that has a prolonged plasma half-life as well as in vitro and in vivo antileukemia activity. To determine its activity in acute myelogenous leukemia (AML), 130 consecutive adult patients between the ages of 16 and 60 with newly diagnosed disease were randomized in a single institution study to receive either IDR in combination with cytosine arabinoside (Ara-C) or standard therapy with daunorubicin (DNR) and Ara-C. The trial was analyzed using the O'Brien-Fleming multiple testing design that allowed for periodic inspection of the data at specific patient accession points. After accrual of 60 patients per arm, analysis showed that patients who received IDR/Ara-C had a superior response compared with those who received standard therapy: 48 of 60 patients (80%) achieved complete remission on the former arm compared with 35 of 60 patients on the latter (58%, P = .005). Logistic regression analysis of factors associated with complete response indicated that treatment with IDR/Ara-C offered a significant advantage to patients who presented with a high initial white blood cell count compared with treatment with DNR/Ara-C. The degree of marrow aplasia was approximately the same on each arm as was nonhematologic toxicity. Overall survival for patients on the IDR/Ara-C arm was 19.5 months compared with 13.5 months on the DNR/Ara-C arm (P = .025) at a median follow-up of 2.5 years. We conclude that IDR/Ara-C can effectively replace standard therapy with DNR/Ara-C in adult patients less than age 60 with newly diagnosed AML.

Adult↗
PubMed1991

Recombinant human granulocyte-macrophage colony-stimulating factor in combination with standard induction chemotherapy in de novo acute myeloid leukemia.

Based on in vitro data suggesting that recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) is capable of stimulating acute myeloid leukemia (AML) blast cells to become more sensitive to cell-cycle-specific drugs we conducted a phase I/II study in de novo AML patients (pts). rhGM-CSF (250 micrograms/m2/d, continuous intravenous infusion) was administered in 18 pts suffering from de novo AML in combination with standard induction chemotherapy (3 + 7 = daunorubicin 45 mg/m2 days 1 through 3, cytosine-arabinoside [Ara-C] 200 mg/m2 continuous infusion days 1 through 7). GM-CSF was started 48 or 24 hours before chemotherapy (prephase) in 14 pts. In four pts with high white blood cell counts (WBC) rhGM-CSF was started after chemotherapy-induced cell reduction (WBC less than 30,000/mm3). During prephase GM-CSF induced an increase in neutrophil and blast cell counts in 13 of 14 and 10 of 14 pts, respectively. In vivo recruitment of leukemic cells into drug-sensitive phases of the cell cycle could be demonstrated by multiparameter cell-cycle analyses in peripheral blood (n = 7) and bone marrow (n = 4) specimens. On day 14, complete aplasia was evident in 17 of 18 pts. GM-CSF was administered until recovery from chemotherapy-induced myelosuppression (absolute neutrophil counts, [ANC] greater than 500/mm3). Fifteen pts (83%) achieved complete remission, 12 did so with one cycle. A shorter duration of neutropenia was evident in these pts compared with historical controls (n = 39), (ANC greater than 500/mm3, day 22.5 +/- 3.4 v 25.2 +/- 3.7, P less than .05). Three pts achieved complete remission after a second cycle (same combination of rhGM-CSF and 3 + 7). Two pts died during bone marrow aplasia because of invasive pulmonary aspergillosis. Clinical side effects possibly related to GM-CSF, mainly fever, diarrhea, and weight gain were mild and tolerable (World Health Organization toxicity grade less than or equal to 2). Together, rhGM-CSF recruits kinetically quiescient AML cells in vivo to enter drug-sensitive phases of the cell cycle and promotes early myeloid recovery from aplasia after exposure to standard induction chemotherapy for AML.

Adult↗
PubMed1991

Effect of tamoxifen on cell lines displaying the multidrug-resistant phenotype.

We examined the effect of tamoxifen (Tmx), verapamil, and daunorubicin (DNR) in two cell lines that displayed the multidrug-resistant (MDR) phenotype and used laser flow cytometry to quantitate intracellular DNR content. In the vinblastine-resistant human lymphoblastic lymphoma cell line CEM-VBL, simultaneous incubation of DNR with Tmx 10 mumol/L or Tmx 50 mumol/L increased intracellular DNR fluorescence in a dose-dependent manner and demonstrated an uptake pattern similar to that seen with DNR and verapamil. Similar results were obtained in the vincristine-resistant human myeloid leukemia cell line HL-60/RV+. Cellular retention of DNR was also measured in both cell lines and results suggested that continuous exposure of the cells to Tmx resulted in higher intracellular DNR content compared with cells resuspended in fresh medium. No effect of Tmx or verapamil was observed in the drug-sensitive parent cell lines CEM or HL-60. Clonogenic experiments were then performed to determine whether Tmx was itself inhibitory to cell growth or whether Tmx potentiated DNR cytotoxicity. Tmx 10 mumol/L did not significantly inhibit either CEM-VBL or HL-60/RV+ cells after a 3-hour exposure followed by culture in methylcellulose. Tmx 50 mumol/L was significantly more inhibitory in both cell lines. However, cells that had been incubated with DNR and Tmx 10 mumol/L demonstrated a marked increment in growth inhibition compared with cells that had been incubated with DNR alone or Tmx 10 mumol/L alone. Based on the data presented here, we suggest that clinical testing of Tmx and DNR be pursued in the setting where MDR may play a role.

Cell Division↗
PubMed1991

DNA and RNA flow cytometric study in multiple myeloma. Clinical correlations.

Flow cytometric studies of cellular DNA and RNA content using the acridine-orange technique were conducted in 81 patients with multiple myeloma (MM). All patients were treated with the M-2 protocol and clinical response was evaluated according to the criteria of the Chronic Leukemia-Myeloma Task Force. Aneuploid DNA stemlines were found in 38.2% of untreated patients with a median DNA index (DNA-I) of 1.15 in marrow aspirates and 1.22 in biopsy specimens. The median percentage of cells with abnormal DNA content was 31.5 (aspirates) and 35 (biopsy specimens) and a positive correlation with the percentage of bone marrow plasma cells was observed. Significantly higher proliferation (S-phase) was found in marrow biopsy specimens as compared with marrow aspirates. Significantly higher RNA content (RNA index [RNA-I]) was observed in aneuploid versus diploid patients in biopsy material. There was no difference in response to the Memorial Hospital M-2 protocol between diploid and aneuploid patients. In patients with DNA-I greater than 1.15 remission duration was shorter as compared with DNA-I less than or equal to 1.15. Furthermore, no difference in cellular RNA content was noted between responders and nonresponders. This study demonstrates no correlation between cellular RNA content and response, as previously described for patients treated with vincristine, Adriamycin, and dexamethasone (VAD), but DNA aneuploidy appears to be an adverse prognostic factor in MM patients treated with the M-2 protocol. It also demonstrates that prognostic models for MM are not universal but depend on the chemotherapeutic regimen used.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

Modulation of drug sensitivity by dipyridamole in multidrug resistant tumor cells in vitro.

The concept of overcoming multidrug resistance using modulators is based on the hypothesis that there will be a synergistic interaction between the modulator and the cytotoxic agent. We examined the ability of dipyridamole (DPM) to synergistically enhance drug sensitivity in drug-sensitive KB-3-1 cells and their drug-resistant variants, KB-GRC1 and KBV1 cells, using median effect analysis to produce a quantitative measure of the extent of synergy. The drug-resistant variants were resistant to vinblastine (VBL), colchicine (COL), and etoposide (VP-16) in the order VBL greater than COL greater than VP-16 on the basis of 50% inhibitory concentration values obtained by clonogenic assay with continuous drug exposure. The extent of staining with the monoclonal antibody HYB-241, directed at a Mr 180,000 form of the mdrI gene product, correlated with drug resistance for all three drugs (r greater than or equal to 0.92). DPM and verapamil elevated the steady state content (Css) of VBL, but there was no correlation between elevation of Css and the extent of synergy observed. DPM enhanced the cytotoxicity of VBL and COL in a synergistic manner in KB-GRC1 cells, and in KBV1 cells DPM interacted synergistically with VBL. VPL was synergistic with VBL only in KB-GRC1 cells. No synergy was observed in the parental KB-3-1 line. These data indicate that, although both DPM and verapamil can increase Css in cells not expressing P-glycoprotein, such an increase was not associated with synergy. In cells expressing mdrl, synergy was observed, and it was greatest for the cytotoxic agent for which expression of mdrl produced the greatest fold-resistance and enhancement of Css. However, neither the level of resistance, the level of expression of mdrl, nor the ability of the modulator to alter Css accurately predicted whether the interaction would be truly synergistic. We conclude that additional factors determine the nature of the drug interaction.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1990

Detection of bcr-abl fusion in chronic myelogeneous leukemia by in situ hybridization.

Chronic myelogeneous leukemia (CML) is genetically characterized by fusion of the bcr and abl genes on chromosomes 22 and 9, respectively. In most cases, the fusion involves a reciprocal translocation t(9;22)(q34;q11), which produces the cytogenetically distinctive Philadelphia chromosome (Ph1). Fusion can be detected by Southern (DNA) analysis or by in vitro amplification of the messenger RNA from the fusion gene with polymerase chain reaction (PCR). These techniques are sensitive but cannot be applied to single cells. Two-color fluorescence in situ hybridization (FISH) was used with probes from portions of the bcr and abl genes to detect the bcr-abl fusion in individual blood and bone marrow cells from six patients. The fusion event was detected in all samples analyzed, of which three were cytogenetically Ph1-negative. One of the Ph1-negative samples was also PCR-negative. This approach is fast and sensitive, and provides potential for determining the frequency of the abnormality in different cell lineages.

Chromosomes, Human, Pair 22↗
PubMed1990

Expression of the macrophage growth factor, CSF-1 and its receptor c-fms by a Hodgkin's disease-derived cell line and its variants.

Expression of the macrophage colony-stimulating factor CSF-1 and its receptor, the product of the protooncogene c-fms, was detected in cell line L428, originally derived from a patient with nodular sclerosis Hodgkin's disease, and its two sublines L428KS and L428KSA. While all lines expressed membrane-associated and soluble CSF-1 proteins, L428KSA secreted 30-fold greater amounts of CSF-1 than the other cells. Three transcripts for CSF-1 (4.4, 3.7, 3.4 kilobases) were expressed in all lines and an additional 2.1-kilobase message in L428KSA. Restriction enzyme fragment analysis did not reveal any gross rearrangements of the CSF-1 gene. L428 and L428KS contained a 4.4-kilobase message for c-fms, whereas L428KSA expressed a smaller 3.8-kilobase c-fms transcript. The c-fms gene structure appeared to be unaltered in all lines by restriction enzyme fragment pattern analysis. Monoclonal anti-c-fms antibody precipitated from all cells a Mr 120,000/130,000 doublet and two lower molecular weight phosphoproteins; however, only L428KSA cells showed evidence for an autocrine growth regulation by CSF-1. DNA ploidy and proliferation kinetic studies suggested that L428KSA were derived from the actively proliferating mononuclear Hodgkin's cell population of the parental cell line. Since the simultaneous expression of CSF-1 and c-fms is a characteristic feature of mononuclear phagocytes, these results suggest that Hodgkin's cells are affiliated with the monocyte/macrophage lineage or, at least, derived from a hemopoietic cell type with the capability for aberrant expression of a monocyte-specific growth factor and its receptor.

Antigens, Surface↗
PubMed1990

Colony-stimulating factors (rhG-CSF, rhGM-CSF, rhIL-3, and BCGF) recruit myeloblastic and lymphoblastic leukemic cells and enhance the cytotoxic effects of cytosine-arabinoside.

Prognostic models for acute myeloid and lymphoid leukemias are presented that demonstrate that cell kinetic quiescence in acute leukemia is associated with poor response to chemotherapy, short remission duration, and survival. Recruitment of cells into the cell cycle should therefore enhance cytotoxic effects of cell cycle - specific chemotherapeutic agents. We previously demonstrated recruitment of myeloid leukemic cells by cytokines. We have now investigated whether recruitment can be used to increase cell killing by cytosine arabinoside (Ara-C). Blast cells from 16 acute leukemias were stimulated with cytokines as follows: 13 acute myeloid leukemias (AML) and 3 chronic myeloid leukemia (CML) in blastic phase (1 lymphoid, 2 myeloid) were treated with recombinant human granulocyte colony stimulating factor (rhG-CSF), recombinant human granulocyte-macrophage colony stimulating factor (rhG-CSF, AMGEN, 500 U/ml each), and recombinant human interleukin-3 (rhIL-3, IMMUNEX, 20 ng/ml), alone and in combination. After 48 h, at the time of maximal DNA synthesis, Ara-C (10(-3) M) was added and cell counts, cytokinetics (DNA/RNA, DNA/bromodeoxyuridine and DNA/Ki67 flow cytometry), and cell viability/clonogenicity (fluorescein diacetate/propidium iodide exclusion flow cytometry) were investigated. In all 13 cases of AML recruitment was found; in 6 of these cases over a three fold increase in S phase (P = 0.008) and a significant (P = 0.004) depletion of G0 was demonstrated. In 9 of 13 patients with AML, the effect of Ara-C was investigated, and in 3 of 5 patients with over three fold increase in S phase, Ara-C toxicity was enhanced. None of the patients with less than a three fold increase in S phase and no demonstrable recruitment from G0 had increased Ara-C cytotoxicity. Ara-C cytoreduction was paralled by reduction in clonogenicity as demonstrated by fluorescein diacetate/propidium iodide (FDA/PI) flow cytometry. Four samples of acute lymphoblastic leukemia (ALL) were treated with low molecular weight B-cell growth factor (15 kDa) and recruitment of aneuploid cells from G0 to G1 was found in all patients (from 19.3% to 84.9%). These results indicate that recruitment of leukemic cells is inducible by cytokines and that the cytotoxicity of cell cycle-specific drugs such as Ara-C can be increased. This concept is presently being tested in vivo.

Adult↗
PubMed1990

Importance of long-term follow-up in evaluating treatment regimens for adults with acute lymphoblastic leukemia.

During the past 20 years, we have treated 250 previously untreated adults (greater than age 15 years) with acute lymphoblastic leukemia (ALL) with five successive multidrug protocols: L2, L10, L10M, L17/17M, and L20. The L10 and L10M protocols had the highest percentage of long-term (greater than 5 years) remissions (52% and 40% respectively) compared with the L2 and more recent protocols (24%-32%); this is partly attributable to a greater prevalence of adverse risk factors among the latter protocols. The overall long-term survival of the first 199 patients with minimum 3 years follow-up is now 31%, with 35% of the 163 patients achieving complete remission (CR) remaining free of relapse for greater than 5 years. The disease-free survival of the 163 patients reaches a plateau of 33% after 6 years. The percentages of patients subsequently relapsing after remaining in continuous CR for 1.5, 3, and 5 years are 42%, 28%, and 6%, respectively; no relapses have yet occurred after 6 years in this series. Postrelapse survival improved progressively with longer duration of first remission. The results of treatment in second or later remission with either chemotherapy or bone marrow transplantation (BMT) were unsatisfactory and there were only a few long-term survivors. Recently we have attempted to select patients at highest risk of early relapse for BMT in first remission, but the number of eligible patients actually having BMTs has been low for a variety of reasons, including early death, failure to reach CR, early relapse, patient refusal, or medical contraindications.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

A study of multidrug resistance and cell kinetics in a child with near-haploid acute lymphoblastic leukemia.

Marked hypodiploidy is found in a small group of patients with acute lymphoblastic leukemia (ALL) and is associated with very poor prognosis. Cells from a patient with near-haploid ALL (karyotype: 27 XY, DNA index = 0.5) were investigated by multiparameter flow cytometry at relapse and at multiple time-points during reinduction chemotherapy. The cell cycle of these near-haploid leukemic blasts and their chromatin structure was studied by acridine orange (AO) DNA/RNA flow cytometric assays. Most leukemic cells were in "G0", and no recruitment of the bone marrow cells into the G1 phase of the cell cycle was found during reinduction therapy with high dose cytosine arabinoside. After two cycles of chemotherapy, the patient achieved clinical remission, but persistent haploid cells were identified by flow cytometry and he relapsed after 8 weeks and died after 16.7 weeks. The leukemic blasts expressed very high levels of a 180 kd p-glycoprotein associated with multidrug resistance and daunomycin efflux could be blocked by verapamil. Expression of gp 180 and the verapamil effect on intracellular daunomycin concentration indicate multidrug resistance. We conclude that cell kinetic quiescence and multidrug resistance may both be factors responsible for the poor prognosis of this patient with near-haploid ALL. Further studies of this patient group should determine if these mechanisms are indeed responsible for the poor prognosis associated with near-haploid leukemia.

Cell Cycle↗
PubMed1990

Kinetic rationale for cytokine-induced recruitment of myeloblastic leukemia followed by cycle-specific chemotherapy in vitro.

In patients with acute myeloblastic leukemia incomplete response to induction chemotherapy and short disease-free survival may be related to cell kinetic quiescence of leukemic cells. In this in vitro study, we tested the hypothesis that treatment with cytokines and subsequent chemotherapy (ARA-C, daunorubicin) can increase proliferation and enhance leukemic cell kill. We evaluated the effects of recombinant human interleukin-3 (rh-IL-3), granulocyte-macrophage colony stimulating factor (rhGM-CSF) and granulocyte colony stimulating factor (rhG-CSF) alone and in combination on AML (N = 11) and blastic phase CML (N = 3) samples. Cellular DNA and RNA, incorporation of bromodeoxyuridine (BrdU), cell growth fraction, cell viability, and differentiation markers were evaluated in vitro. A decrease of the quiescent cell population (p = 0.003) and an increase in S-phase cells (p = 0.001) was observed in 8/11 AML samples treated with cytokine combinations. Pronounced heterogeneity or proliferative response was seen between individual cases and different cytokines, but in the majority of the samples IL-3 was most effective. Significantly increased Ki67 expression (p = 0.009) and BrdU incorporation (p = 0.01) were also found after exposure to cytokines indicating an increase in growth fraction. DNA synthesis time was unaffected. Eight samples of AML were treated for 24 hr with ara-C following 2 days of in vitro cytokine incubation. Evaluation of leukemic cell kill showed increased cytotoxicity in three of those five samples which had significant depletions of G0 cells and increases in S-phase. None of the leukemic samples without recruitment from G0 had an increase in ARA-C cytotoxicity. This study provides detailed cell kinetic analysis of cytokine effects on AML blasts and provides a rationale for a novel approach to the treatment of AML.

Antineoplastic Combined Chemotherapy Protocols↗