UMLS:C0023467 - FACTA Search

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Query: UMLS:C0023467 (acute myeloid leukemia)
35,200 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Expression of P-glycoprotein (PGP), the product of the multi-drug resistance mdr1 gene was studied by immunocytochemistry on bone marrow slides using JSB1 monoclonal antibody and the alkaline phosphatase-antialkaline phosphatase (APAAP) and avidin-biotin-peroxidase (ABC) techniques in 82 cases of untreated myelodysplastic syndromes (MDS), of whom ten had evolved to AML (MDS-AML). The relationship between PGP expression, myeloperoxidase activity and immunophenotype of blast cells, karyotype and outcome was also analyzed. PGP expression was found in the blasts of 34 of the 82 patients (41%), the majority of blasts being stained in positive cases. PGP positivity was rare in 'low risk' MDS (RA and RARS: 2/12 cases) as opposed to 'high risk' MDS (RAEB, RAEB-T, CMML: 25/60 cases) and MDS-AML (7/10 cases) (p = 0.04). PGP expression was positively correlated to the presence of myeloperoxidase activity in less than 3% of blasts (p = 0.025), and CD34 antigen expression (p = 0.04), whereas CD33 antigen expression had borderline significance (p = 0.07), demonstrating that PGP expression predominated in blasts with an immature phenotype. An abnormal karyotype, and especially the presence of monosomy 7, was not correlated to a higher incidence of PGP expression, however. There was a trend for more frequent progression to AML and for shorter survival in PGP-positive cases, but differences with PGP-negative cases were not significant. Twenty patients received intensive anthracycline-Ara-C chemotherapy and ten (50%) achieved complete response, including 9/13 (69%) PGP-negative cases and 1/7 (14%) PGP-positive cases (p = 0.03). Twenty other patients were treated with low-dose Ara-C and ten (50%) responded (complete or partial response). PGP-positivity did not negatively affect response to low-dose Ara-C: 4/11 responses in PGP-negative, and 6/9 responses in PGP-positive patients (p = 0.18). Because the treatment choice in advanced MDS (especially between anthracycline-Ara-C or low-dose Ara-C, chemotherapy) is difficult, our preliminary therapeutic results suggest that the analysis of PGP expression could have practical importance in MDS. These findings however, will have to be confirmed on larger numbers of patients. Clinical trials using drugs potentially reverting mdr, activity could also be warranted in MDS.
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PMID:Expression of the multidrug resistance P-glycoprotein and its relationship to hematological characteristics and response to treatment in myelodysplastic syndromes. 751 32

To evaluate the clinical relevance of multidrug resistance (MDR) phenotype, the intracellular daunorubicin accumulation (IDA) and P-glycoprotein (P-gp) expression were investigated in 87 adult patients with acute leukemia: 69 patients with de novo acute myeloid leukemia (AML), 10 with AML at relapse, and eight with secondary leukemia to myelodysplastic syndromes (MDS-AML). IDA and P-gp expression were determined by double-labeling flow cytometry analysis. Of 87 patients, 36 expressed P-gp (41%). P-gp expression was more frequently observed in AML at relapse and MDS-AML as compared with de novo AML (P = .0001). P-gp expression was significantly associated with CD34 expression (P = .0003) and chromosome 7 abnormalities (P = .027). A significantly reduced IDA was observed in P-gp+ as compared with P-gp- patients (P = .0007). Of the 87 patients, 51 achieved complete remission (CR). A reduced IDA was observed in patients in failure as compared with patients in CR (22% +/- 17% v 42% +/- 21%; P = 10(-4). Twelve of 36 P-gp+ patients as compared with 40 of 51 P-gp- patients achieved CR (33% v 78%; P = 10(-4). The prognostic value of IDA and P-gp expression was confirmed in multivariate analysis. These data suggest that the determination of IDA and P-gp expression may be useful in designing therapy for patients with AML.
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PMID:Predictive value for treatment outcome in acute myeloid leukemia of cellular daunorubicin accumulation and P-glycoprotein expression simultaneously determined by flow cytometry. 753 92

The efficacy of verapamil and cyclosporine A as modulators of P-glycoprotein, the multidrug resistance (MDR1) gene product, was studied in leukemic blast cells from 56 patients with de novo acute myeloid leukemia (AML) in vitro. Rhodamine123 dye-efflux was measured flow cytometrically as a cellular parameter reflecting P-glycoprotein activity. While dye-efflux was measurable in 3/4 of the cases, the capacity of the P-glycoprotein inhibitors varied substantially among patients. In 23 patients, P-glycoprotein function was completely inhibited by the resistance modulators, whereas in 17 patients neither verapamil nor cyclosporine had any reverting effect on dye-efflux at concentrations even 10-times higher than achievable in vivo. Cells with a drug-sensitive rhodamine123-pump effluxed more efficiently (p = 0.0016) and contained significantly higher levels of MDR1 specific RNA transcripts (p = 0.0002), as determined by quantitative PCR, than cells exhibiting an efflux process that could not be inhibited. However, flow cytometric evaluation of the staining of gated blast cells with the anti-P-glycoprotein antibody, 4E3.16, revealed no difference in P-glycoprotein expression between modulator-sensitive and -insensitive cases (p = 0.86), indicating disproportionate translation of MDR1 mRNA. In leukemic cell populations with increased P-glycoprotein function that could be inhibited, significantly more blasts expressed the progenitor cell antigen, CD34 (median 83%), than was the case in leukemias with P-glycoprotein activity that could not be inhibited (median 7%) (p = 0.0001). The present study demonstrates that a substantial fraction of AML patients constitutively display a drug-efflux mechanism suggestive of P-glycoprotein activity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Modulation of multidrug resistance in de novo adult acute myeloid leukemia: variable efficacy of reverting agents in vitro. Eastern Cooperative Oncology Group. 754 Sep 3

High spontaneous proliferation of acute myeloid leukemia (AML) in vitro is an unfavorable, tumor-specific prognostic factor. We investigated the frequency of drug-resistant tumor cells with high proliferating capacity in de novo AML and analyzed the expression of multiple resistance parameters in relation to the response to chemotherapy and overall survival. Thirty-eight patients were included in this study. P-glycoprotein (P-gp) expression was found in 28/38 patients and was associated with lower intracellular accumulation of DNR (P = 0.0001). Thirty-five out of 38 patients were treated with 1-2 regimens of daunorubicin (DNR)/cytarabine (Ara-C), and 57% attained a complete remission (CR). Failure to achieve a CR correlated with autonomous growth (P = 0.0064), CD34 and P-gp expression alone (P = 0.0005 and P = 0.048 respectively), and with simultaneous expression of P-gp and CD34 (P = 0.0001), but not with expression of the non-P-gp drug resistance associated-protein (p110), the multidrug resistance-associated protein (MRP), Ara-CTP formation or Ara-C incorporation, respectively. AML cells with CD34/P-gp double expression were more frequently observed in samples with high autonomous growth (P = 0.003). The median survival was 6 months in CD34+/P-gp+ patients as compared with 15 months in other AML patients (P = 0.003). In patients with de novo AML who fail on chemotherapy, a population of autonomously proliferating, immature AML cells with a multidrug resistant phenotype can be recognized. These cells thus show primary resistance to chemotherapy and have the potential for rapid regrowth, leading to resistant disease.
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PMID:Multidrug resistant cells with high proliferative capacity determine response to therapy in acute myeloid leukemia. 754 Oct 95

Tamoxifen and its main metabolite N-desmethyltamoxifen (NDMTmx) have been shown to increase intracellular daunorubicin (DNR) levels in human leukemia cell lines that display the multidrug resistant (MDR) phenotype. We designed a phase I dose escalation study of Tmx (200-700 mg/day p.o. for 7 days) in combination with a fixed dose of DNR (50 mg/m2 intravenously on days 5, 6 and 7) in patients with advanced leukemia to determine whether this combination could be given safely and whether plasma levels of 10 microM, the effective in vitro MDR modulator concentration, could be achieved. Pharmacologic studies of Tmx, NDMTmx and DNR, and its main metabolite daunorubicin-ol (DNR-ol) were performed as was determination of P-glycoprotein (Pgp) using a monoclonal antibody that recognizes an external epitope of the molecule. A total of 14 patients (median age 50, range 22-67) were treated at the following dose levels: 200 mg/day: three patients; 400 mg/day: four patients; 550 mg/day: three patients; and 700 mg/day: four patients. Two patients with relapsed AML achieved remission. Toxicity of the combination was similar to that seen with DNR alone and no severe hepatic, cardiac or retinal toxicity was noted. Plasma Tmx levels approached 7 microM at the two highest dose levels studied; plasma levels of NDMTmx were slightly less. The area under the curve for DNR and its main metabolite daunorubicin-ol (DNR-ol) did not show significant changes with escalation of Tmx dose. This phase I study suggests that concentrations of Tmx high enough to reverse the MDR phenotype can be approached and that the combination of high-dose Tmx with a standard dose of DNR has an acceptable toxicity profile. More evaluation in phase II studies is necessary to define further its role as an MDR modulator.
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PMID:Phase I trial of high-dose tamoxifen as a modulator of drug resistance in combination with daunorubicin in patients with relapsed or refractory acute leukemia. 756 1

This study was aimed at evaluating the influence of 5637-conditioned medium (5637-CM) and human recombinant cytokines on both expression and function of P-glycoprotein (P-gp) in TF-1, a GM-CSF/IL-3-dependent acute myeloid leukemia cell line which constitutively expresses functional P-gp. P-gp expression was measured by flow cytometry using MRK16 monoclonal antibody. P-gp function was measured by rhodamine 123 (Rh 123) efflux kinetics. When TF-1 cells were cultured with 5637-CM (50% v/v), both P-gp expression and P-gp efflux capacity were increased in a time-dependent manner with a 4-fold increase in P-gp expression level at day 6 whereas TF-1 cell differentiation status remained unchanged as assessed by morphological studies, phenotypical and cytochemistry analysis. Recombinant cytokines including GM-CSF, G-CSF, IL-1 beta, IL-6, stem cell factor, LIF, erythropoietin, and IL-3 had no effect on P-gp expression whereas TNF alpha induced dose- and time-dependent P-gp and mdr-1 gene overexpression. However, TNF alpha-induced P-gp overexpression had no influence on P-gp efflux capacity. Furthermore, when TF-1 cells were exposed to IL-3 for periods longer than 1 month, we found that P-gp efflux capacity was increased as compared to cells cultured with GM-CSF whereas P-gp expression was unchanged. Both TNF alpha and IL-3 did not induce TF-1 differentiation. Collectively, these results suggest that cytokines may influence both expression and function of P-gp in TF-1 cells without interfering with their differentiation status. In contrast to cytokines, phorbol esters enhanced expression and efflux capacity of P-gp in parallel with TF-1 cell monocytic differentiation. Finally, our study suggests that paracrine and/or autocrine secretion of cytokines may interfere with P-gp activity in some acute myeloid leukemia cells.
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PMID:Effect of 5637-conditioned medium and recombinant cytokines on P-glycoprotein expression in a human GM-CSF-dependent leukemic myeloid cell line. 756 16

We have investigated the self-renewal capacity (PE2) and in vitro sensitivity to cytosine-arabinoside (ara-C) and daunorubicine (DNR) of leukemic progenitors (CFU-AML) to determine the significance of these tests for predicting induction treatment outcome in 75 adult acute myeloid leukemia (AML) patients. In addition, in a part of this group of patients (n = 46) we determined the expression of P-glycoprotein (P-gp) immunocytochemically and correlated those results with the therapeutic response. We have evaluated 66 patients who showed the following responses: 28/66 complete remissions (CR), 16/66 resistant leukemias (RL) and 22/66 early deaths (ED). The PE2 value was significantly higher in patients with RL than in patients with CR (p < 0.00375). CFU-AML sensitivity to ara-C and DNR alone was not different between response groups, but the difference in CFU-AML sensitivity to the combination of drugs between patients with CR and RL was not significant, although a trend was noted (p < 0.06). P-gp expression was found in only 1/18 patients who achieved CR but in 9/11 patients with RL and 7/11 patients with ED, which is a highly significant difference (p < 0.0006). We concluded that both PE2 and P-gp expression in AML cells are valuable predictors of therapeutic response in adult AML and should be included in creating the best therapeutic approach to AML patients.
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PMID:In vitro drug sensitivity of leukemic progenitors and P-glycoprotein expression in adult acute myeloid leukemia: correlation with induction treatment outcome. 762 94

To clarify the common characteristics among P-glycoprotein (P-gp)-expressing hematological malignancies and whether chemotherapies could or could not induce P-gp expression, we analyzed P-gp/MDR1 expression in tumor cells from 200 Japanese patients (104 with acute myeloblastic leukemia (AML); 30 with acute lymphoblastic leukemia (ALL); 66 with mature lymphoid malignancies). Functional P-gp expression was examined by Rhodamine-123 efflux test, and estimated with the data by RT-PCR method. In mature lymphoid malignancies, the cells of T or natural killer (NK) cell malignancies frequently expressed P-gp/MDR1. In AML, frequent P-gp/MDR1 expression was associated with the expression of CD7 or c-kit and with 8; 21 chromosomal translocation (p < 0.01), which were thought to be the characteristics of the hematopoietic stem cell. Though the expression of P-gp/MDR1 was more frequent at onset than at relapse phase, the increase is thought to result from the expansion of blastic fraction expressing P-gp/MDR1. In ALL, P-gp/MDR1 expression was not frequent in B-cell precursor lineage (three of eighteen patients), but the incidence was high in CD7(+) surface CD3(-) cases (seven of the cases). These results indicate P-gp/MDR1 expression is more frequently in the tumor of T, NK cell and stem cell, reflecting the characteristics of its normal counterpart.
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PMID:[P-glycoprotein expression in hematological malignancies]. 764 52

Microspectrofluorometry allows the analysis of fluorescent molecules such as anthracyclines in the nucleus of isolated living cells. Using this technique, we confirmed that the amount of doxorubicin or THP-doxorubicin incorporated into the nucleus was related to the resistant or sensitive character of K562 cells. It was then extended to the study of fresh leukemic cells and kinetic studies were performed allowing the calculation of the retention rate (RR) of anthracycline (THP-doxorubicin) into the cell nucleus. A reproducibility study confirmed the accuracy of the method. Blast cells collected in patients with acute myeloid (n = 22) or lymphoid (n = 8) leukemia, at diagnosis (n = 26), or in relapse (n = 4) have been studied. RR varied from 8 to 98% independently of the type of leukemia or the clinical status. RR did not correlate either with P-glycoprotein or with CD34 expression although this latter result should be confirmed on a higher number of subjects. Among 18 patients presenting with AML at diagnosis, 14 have been treated with intensive chemotherapy including anthracyclines; the only one who had resistant disease had the lowest RR value. In conclusion, the results obtained here show that microspectrofluorometry allows the performance of kinetic studies on fresh leukemic cells in order to quantify chemo-resistance phenomena related to drug transport.
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PMID:In vitro study of THP-doxorubicin retention in human leukemic cells using confocal laser microspectrofluorometry. 764 25

Multidrug resistant (MDR) phenotype is characterized by a defect in drug accumulation caused by overexpression of a transmembrane glycoprotein, the P-glycoprotein (P-gp). MDR phenotype can be characterized either with monoclonal antibodies raised against P-gp or with functional tests, most often based on the incorporation of fluorescent compounds. In the present study, data obtained with the monoclonal antibodies C219, JSB1 and MRK16 are compared to those of functional tests performed by flow cytometry including uptake of daunorubicin (DNR), Rhodamine 123 (Rh 123) or Hoechst 33342. Sensitive and resistant cell lines K562S, K562R, KBA1 and KB31, derived either from a human chronic myeloid leukemia or from a human epithelial carcinoma, were used. In resistant cells, P-gp expression was revealed with either the monoclonal antibodies C219, JSB1 or MRK-16. The most specific results were obtained with MRK-16. With functional tests, no matter which dyes were used, the fluorescence was always stronger in sensitive than in resistant cells. However, with DNR and Hoechst 33342, an incorporation of these dyes was exhibited in resistant cells. This phenomenon was not observed with Rh 123, which makes it possible to distinguish clearly between sensitive and resistant cells and to detect as few as 1% of resistant cells. Because of its high sensitivity, the functional test involving incorporation of Rh 123 was successfully used in acute myeloid leukemia to detect multichemoresistant cells.
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PMID:Evaluation of multidrug resistant phenotype by flow cytometry with monoclonal antibodies and functional tests. 765 50

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