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

A 4-day colorimetric tetrazolium dye (MTT) assay was used to assess the cytotoxicity of adriamycin (ADM), vincristine (VCR), and idarubicin (IDA) in blasts isolated from 37 patients with newly diagnosed and pretreated acute myeloid leukemia (AML). The effect of verapamil (VRP) as a chemosensitizer was studied in relation to the expression of the membrane efflux pump P-glycoprotein (PGP) as determined by a semiquantitative flow-cytometric proceder. A slight positive correlation was found between the fraction of cells expressing PGP and the ID50 values for ADM and VCR, but not between cellular PGP content and sensitivity to IDA. The overall data showed no significant sensitization effect of VRP. However, in specimens with more than 10% cells expressing PGP, 2 microM VRP sensitized cells to ADM and VCR significantly. The median of sensitization ratios (SRs), i.e., the ratios of cytotoxic drug ID50 in the absence/presence of VRP, were 1.89 and 2.0, respectively. No sensitizing effect of VRP on the cytotoxicity of IDA was observed. Related to the clinical status, the median fraction of PGP-positive blasts was elevated fourfold in pretreated patients (n = 16) in comparison to patients with de novo AML (n = 19). No differences in ID50 values were observed between newly diagnosed and pretreated patients. However, SRs for ADM and VCR were higher in samples of pretreated patients compared with de novo AML. PGP-mediated cellular drug resistance may thus be circumvented in leukemic blasts by application of chemosensitizers or, potentially, alternative anthracyclines.
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PMID:Cytotoxicity of adriamycin, idarubicin, and vincristine in acute myeloid leukemia: chemosensitization by verapamil in relation to P-glycoprotein expression. 136 Aug 20

Thirty four patients with acute myeloid leukemia (AML) (30 de novo and 4 relapsed) were evaluated for P-glycoprotein (P-gp) expression, and in vitro chemosensitivity. The P-gp expression was evaluated by immunohistochemical method using JSB-1 monoclonal antibody and the results were visualized by peroxidase-antiperoxidase goat antimouse antibody and the in vitro chemosensitivity was measured by the semiautomated MTT colourimetric assay method. Depending upon the percent cells expressing P-gp and the intensity of P-gp staining, the samples were graded as absent, mild or strong for the relative P-gp expression, which was further correlated with the in vitro chemosensitivity and the clinical response of the tumors. Expression of P-gp was seen in 17 of the 30 de novo AML cases and all four relapse cases. Patients with no P-gp expression showed in vitro chemosensitivity while those with strong P-gp expression were resistant in vitro. Patients with mild P-gp expression showed varied chemosensitivity. P-gp expression correlated with clinical response to chemotherapy. Seven out of 11 patients with no P-gp achieved complete remission (C.R.). The other four died early in induction. Of five patients who expressed strong P-gp, four had resistant disease and the autopsy study of the remaining patient who died in induction revealed persistent disease. Of the 10 de novo AML patients who had mild P-gp expression, five achieved C.R. while one had resistant disease and four died in induction. All the four relapsed AML showed mild P-gp expression.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Expression of the multidrug transporter P-glycoprotein and in vitro chemosensitivity: correlation with in vivo response to chemotherapy in acute myeloid leukemia. 168 90

We applied the MTT dye reduction assay to the anti-cancer drug sensitivity test using short-term microplate cultures. Blast cells were cultured with approximately 25 anti-cancer drugs for 4 days. After cultivation, MTT dye was placed in each well, and the formazans generated by living cells were dissolved in acidified isopropyl alcohol. The absorbance of each well was measured at a scanning microplate photometer. When we made the table of the cytotoxicity index (CI) that was classified into anti-cancer drugs and concentrations for each leukemic sample, it was possible to compare efficacy with different drugs and to select the effective ones. Retrospectively, the in vitro results were compared with the clinical responses of the 34 patients (26 of acute lymphocytic leukemia [ALL] and eight of acute nonlymphoblastic leukemia [ANLL]) who were treated by combination chemotherapy. The following results were obtained: true-positive rate, 78.1%; true-negative rate, 57.1%; and predictive accuracy, 74.4%. Therefore, the MTT assay-CI table might serve as a reliable tool for the selection of effective chemotherapy in patients with acute leukemia.
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PMID:An in vitro chemosensitivity test for the screening of anti-cancer drugs in childhood leukemia. 230 78

We describe the application of a simple, rapid, semi-automated assay to the sensitivity testing of cytotoxic drugs in 23 patients with acute myeloid leukaemia (AML). The survival of blast cells from the bone marrow was measured by the MTT assay after 48 h continuous exposure to drugs both singly and in combination. There was a linear relationship between the number of leukaemic cells and the optical density of the formazan produced. The assay demonstrated a variation in drug sensitivity between patients. The technique was reproducible and there was no significant difference in response between blast cells obtained from bone marrow or from peripheral blood. Preliminary results show a correlation between in vitro and in vivo data. The test can be repeated throughout the course of the disease to help identify any change in tumour sensitivity. This technique appears to give useful information to assist in the management of acute myeloid leukaemia.
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PMID:Appraisal of the MTT assay as a rapid test of chemosensitivity in acute myeloid leukaemia. 276 67

The effect of stimulating acute myeloid leukemia blast cells with a combination of growth factors (G-CSF, GM-CSF, and IL-3) on cellular resistance to the antileukemia drugs Ara-C, daunorubicin, aclarubicin, and mitoxantrone was studied. For assessment of in vitro cellular drug resistance the MTT assay was employed. Stimulated cells showed enhanced sensitivity to Ara-C (p < 0.02), whereas a significant increase in cellular drug resistance to daunorubicin (p < 0.02) was observed. Variable and statistically non-significant changes in drug resistance to aclarubicin and mitoxantrone was induced by stimulation of the blast cells. We conclude on the basis of these observations that myeloid growth factors should be used with caution in combination with daunorubicin in AML treatment until further confirmatory evidence has been presented by other investigators.
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PMID:Synergistic and antagonistic effects of myeloid growth factors on in vitro cellular killing by cytotoxic drugs. 768 27

In normal hematopoiesis, granulocyte macrophage-colony stimulating factor (GM-CSF) is known to stimulate the proliferation and differentiation of myelo-monocytoid lineage, while Steel factor (SLF) has been supposed to support the proliferation of more primitive hematopoietic progenitors including stem cells. We investigated the stimulatory effect of SLF and GM-CSF in twelve cases of acute myeloid leukemia (AML) cells in vitro by MTT assay. In 10 out of 12 cases, SLF or GM-CSF stimulated the proliferation of leukemic cells in short term liquid culture. In 7 out of these 10 cases, the leukemic cells responded to both cytokines. To investigate the possibility of the clinical application of these cytokines by combination with cell cycle-specific anti-tumor reagents, we assessed the effects of SLF and GM-CSF on the modulation of the cell cycle and sensitivity against cytosine arabinoside (ara-C) in a human factor-dependent leukemic cell line, MO7e. Flow cytometric analysis revealed the effect of cell recruitment into the cell cycle in the quiescent MO7e cells by exposure to these cytokines. The drug-sensitivity test using the MTT assay system demonstrated that pre-treatment with each cytokine enhanced sensitivity of ara-C. Furthermore, by combination of SLF and GM-CSF, the ara-C sensitivity was significantly wore graty enhanced than by each cytokine alone. These data suggest that combined pre-treatment with SLF and GM-CSF may provide new benefits for cure-oriented chemotherapy of AML followed by bone marrow transplantation or peripheral blood stem cell transplantation.
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PMID:[Enhanced sensitivity to cytosine arabinoside by combined stimulation of steel factor and GM-CSF in a factor-dependent leukemic cell line, MO7e--in terms of a possible clinical application to AML treatment]. 768 60

The MTT assay, a colorimetric assay, is found to be suitable for chemosensitivity testing. Recently, it has been suggested that hematopoietic growth factors (HGF) may enhance the effects of cytostatic drugs in acute myeloid leukemia (AML). We therefore studied the effects of granulocyte colony-stimulating factor (G-CSF), interleukin 3 (IL-3), and granulocyte-macrophage colony-stimulating factor (GM-CSF) combined with cytosine arabinoside (Ara-C), daunorubicin (DNR), mitoxantrone (MXT), or etoposide (VP-16) by using the MTT assay. The results were compared with in vitro clonogenic assays. Briefly, AML cells of nine patients were incubated in the presence or absence of G-CSF, IL-3, or GM-CSF under serum-free conditions for 24 hours. Next, for the MTT assay, Ara-C (final dilution range: 0.0024-240 micrograms/ml), DNR (final dilution range: 0.05-3.2 micrograms/ml), MXT (final dilution range: 0.05-3.2 micrograms/ml), or VP-16 (final dilution range: 0.1-100 micrograms/ml) were added and incubated for 48 hours. Cell survival was determined and IC75 values (75% reduction as compared to control cultures) were calculated. For clonogenic assays, the three lowest drug concentrations were used. After 48 hours, the clonogenic response was determined in serum-free, semi-solid cultures with G-CSF, IL-3, or GM-CSF. The results obtained by the MTT assay showed no significant enhancement of cytotoxicity by HGF on cytostatic drug preincubated cells compared to cytostatic drugs alone. The results obtained by the clonogenic assays showed increased cytotoxicity of Ara-C combined with G-CSF, IL-3, or GM-CSF. The median IC75 values of Ara-C decreased from 0.056 to 0.0168 microgram/ml with G-CSF (p = 0.01), from 0.108 to 0.0168 microgram/ml with IL-3 (p = 0.004) and from 0.12 to 0.0204 microgram/ml for GM-CSF (p = 0.02). Only moderate enhanced cytotoxicity was observed when VP-16 was combined with IL-3 (p = 0.036) or GM-CSF (p = 0.036), but not with G-CSF. No enhanced cytotoxicity of DNR and MXT to clonogenic AML cells was found when these agents were combined with HGF stimulation. The results indicate that the MTT assay underestimates HGF enhanced cytotoxicity of Ara-C or VP-16 to clonogenic cells. Therefore, the assay is not useful for accurately detecting differences of clonogenic response due to the proliferative status of cells. In this paper, the potential explanations for the failure of the MTT assay are discussed.
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PMID:Enhanced chemosensitivity in acute myeloid leukemia by hematopoietic growth factors: a comparison of the MTT assay with a clonogenic assay. 769 94

In a panel of acute myeloblastic leukemia (AML) cell lines, representative of distinct differentiation stages, we investigated the possible correlation between drug-resistance and both expression and function of the multidrug resistance (MDR)-related P-glycoprotein (P-gp). The AML cell lines were KG1a, KG1, TF1, HEL, ML1, and two non drug-selected P-gp positive subclones originating from HL-60 (HL-60JD) and U937 (U937AQ). All these cells overexpressed the mdr1 gene (analyzed by RT-PCR) and displayed variable levels of P-gp expression. Flow cytometric semi-quantitative evaluation of P-gp with two P-gp specific monoclonal antibodies (MRK16 and UIC2) showed the following P-gp expression hierarchy: TF1 < KG1a < HEL < KG1 < HL-60JD < ML1 < U937AQ; the latter expressing 13 times more P-gp than TF1. When P-gp function was assessed by Rhodamine 123 (Rh123) efflux kinetics, we found that only KG1a and KG1 cells, which have an early (immature) CD34+ CD33- CD38- phenotype, and to a lesser extent TF1, with an intermediate (CD34+ CD33+ CD38+) phenotype, displayed significant P-gp activity which could be inhibited by both verapamil and SDZ PSC 833. In contrast, the other more mature CD33+ CD34- AML cell lines presented no Rh123 efflux capacity although they expressed higher P-gp levels. Daunorubicin (DNR) accumulation studies showed that inhibitors of P-gp increased DNR accumulation only in the immature AML cells whereas they had no impact on the mature AML cell lines. MTT drug cytotoxicity assay confirmed that the immature AML cells were 10-15-fold more resistant to DNR than the mature AML cells. Although P-gp inhibitors were able to increase the cytotoxicity of DNR in AML cells which displayed functional P-gp, they could not increase DNR cytotoxicity to levels comparable to that of the CD34- CD33+ cells, suggesting that DNR resistance of immature AML cells may not solely be related to P-gp. With drug-selection, AML subclones displayed higher levels of P-gp expression and higher extruding capacities, and therefore chemoresistance, and this independently of their initial differentiation phenotype. Finally, this study provides evidence for a lack of correlation between expression and function of P-gp in AML cells; this relationship being dependent upon leukemic cell differentiation in unselected myeloid leukemic cells.
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PMID:Lack of correlation between expression and function of P-glycoprotein in acute myeloid leukemia cell lines. 776 42

The sensitivities of AML and BCLL blasts to daunorubicin have been determined, using an in vitro (MTT) assay of resistance, and compared with the sensitivities of normal haemopoietic populations and cells of the multidrug-resistant, T-lymphoid line CEM VLB100; The role of the drug-efflux pump, P-glycoprotein, was determined by adding the 'modifier' cyclosporin and by measuring numbers of P-glycoprotein positive cells by immunofluorescence. ID50s for 17 cases of de novo AML varied from 5 to 300 ng/ml giving a median of 105 ng/ml which was similar to the median of 11 normal marrow mononuclear cell preparations (80 ng/ml) but considerably less than the median ID50 of eight blood lymphocyte samples (3500 ng/ml). ID50s for five relapsed and two refractory AML samples ranged from 27 to 240 ng/ml, well within the de novo range: we had obtained presentation samples for two of these and, in both cases, ID50s were lower at relapse. ID50s, however, were raised in seven marrow mononuclear cell populations taken soon after remission induction (ID50 for remission MNC and normal MNC = 200 and 80 ng/ml, respectively); this may reflect either a property of regenerating populations, or an activation of cellular resistance mechanisms following chemotherapy. ID50s for 17 cases of BCLL ranged from 7 to 200 ng/ml with a median of 48 ng/ml which was significantly lower than the ID50 of AML blasts or of blood lymphocytes. Cyclosporin induced less than two-fold reductions in ID50s of blood lymphocytes, marrow mononuclear cells and de novo AML and BCLL blasts despite giving log reversals in resistance in the CEM VLB100 line. This reflected numbers of P-glycoprotein positive cells in our samples, which were high in CEM VLB100 but low in fresh normal or leukaemic cell suspensions. For both de novo AML and BCLL groups, however, the change in ID50, on addition of cyclosporin, was significant. These data imply a minor role for P-glycoprotein in drug resistance of leukaemic blasts. Nevertheless, there was a positive correlation between daunorubicin ID50s in de novo AML and time to remission which confirms that in vitro chemosensitivity assays can provide a useful measure of in vivo resistance.
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PMID:In vitro drug resistance in acute myeloid and chronic B-lymphocytic leukaemic blasts and in normal blood and marrow populations. 793 44

In view of cellular immunotherapy with cytotoxic monocytes in minimal residual leukemia we have studied the effects of monocytes on the growth and survival of leukemic cells from cell lines and from patients with acute myeloid leukemia (AML). Using highly purified and interferon-gamma (IFN gamma) activated human monocytes, monocyte-mediated cytotoxicity (MMC) was evaluated in an MTT-based colorimetric cytotoxicity assay against six human leukemic cell lines (U937, THP1, KG1, K562, HL60, and 1,25(OH)2D3 differentiated HL60 cells) and cells from AML patients. Leukemic cells from cell lines with an immature phenotype were found to be resistant to MMC, whereas leukemic cells with a more mature and monocytic phenotype were sensitive. This paralleled the sensitivity to tumor necrosis factor-alpha (TNF-alpha). AML cells from patients with an immature phenotype (FAB-M1/M5A) were significantly less sensitive to MMC as compared to more mature AML cells (FAB-M2/M4/M5B). The growth stimulatory effects of non-activated monocytes on immature AML cells could be abrogated in the presence of IFN gamma or IL-3 and GM-CSF. In addition, these cytokines further potentiated MMC, preferentially affecting cells with a more mature phenotype. AML cells with an immunologically immature phenotype (CD34(high), HLA-Dr(low), CD13(low), CD14(low)) were revealed as the least sensitive cells to MMC. The growth stimulatory effects of IL-3/GM-CSF with or without TNF-alpha on AML cells correlated with resistance to MMC. In addition, the cytolytic effects of TNF-alpha in the presence of IFN gamma correlated with an increased susceptibility of AML cells to MMC. In conclusion, our data strongly indicate that MMC is related to maturation in AML, which is correlated to the differential stimulatory and cytolytic effects of monocyte-derived cytokines such as IL-3, GM-CSF, and TNF-alpha.
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PMID:Maturation-dependent susceptibility to monocyte-mediated cytotoxicity in acute myeloid leukemia. 805 79


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