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Hepatitis C , Enfermedades del Sistema Nervioso Periférico , Antivirales/uso terapéutico , Hepacivirus/genética , Virus de la Hepatitis B , Hepatitis C/tratamiento farmacológico , Humanos , Enfermedades del Sistema Nervioso Periférico/inducido químicamente , Enfermedades del Sistema Nervioso Periférico/tratamiento farmacológico , Rituximab/uso terapéutico , Activación ViralRESUMEN
Acquired haemophilia A (AHA) is a rare bleeding disorder due to autoantibodies directed against coagulation factor VIII. The treatment is based on recombinant activated factor VII and activated prothrombin complex concentrate. However, mainly in older patients, severe thrombotic complications have been reported. Here we report the different therapeutic approaches in 4 cases of elderly patients with AHA and co-morbidities.
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Hemofilia A/tratamiento farmacológico , Inmunosupresores/uso terapéutico , Factores de Edad , Anciano , Anciano de 80 o más Años , Ciclofosfamida/uso terapéutico , Quimioterapia Combinada/métodos , Factor VIII , Femenino , Hemofilia A/sangre , Humanos , Masculino , Metilprednisolona/uso terapéutico , Prednisona/uso terapéutico , Estudios RetrospectivosRESUMEN
In this work three human cell lines with multidrug resistance (MDR) caused by a P-glycoprotein (PGP) overexpression, CEM VLB, HL60 DNR, LOVO DX and two cell lines with MDR associated with a multidrug related protein (MRP) or a lung resistance-related protein (LRP) overexpression named GLC4 ADR and SW1573/2R120 were tested for Amifostine protection against Daunorubicin, Doxorubicin, Idarubicin and Mitoxantrone toxicity. This class of anticancer agents was chosen because they are commonly used in the first line treatments of acute leukemias where a PGP, an LRP or an MRP overexpression often occurs even at onset. A 7-day incubation with escalating doses of anticancer agents with or without a 15 minute preincubation in Amifostine or its active metabolite WR-1065 were used. In conclusion, in none of the MDR positive and negative cell lines did Amifostine modify the toxicity of the anticancer drugs. The observation that even the WR-1065 metabolite gave no protection against Anthracyclines toxicity strengthened the data and provided confirmation for the further in vivo testing of the safety and efficacy of Amifostine in leukemias.
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Amifostina/farmacología , Antibióticos Antineoplásicos/farmacología , Antineoplásicos/toxicidad , Citoprotección , Mitoxantrona/toxicidad , Transportadoras de Casetes de Unión a ATP , División Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Interacciones Farmacológicas , Resistencia a Múltiples Medicamentos , Humanos , Mercaptoetilaminas/farmacología , Protectores contra Radiación/farmacología , Células Tumorales CultivadasRESUMEN
Liposomal formulations of anthracyclines have been developed to increase their delivery to solid tumors while reducing toxicity in normal tissues. DaunoXome (DNX, NeXstar) is a liposomal-encapsulated preparation of daunorubicin registered for treatment of Kaposi's sarcoma that during prior in vitro studies showed a toxicity to leukemic cells at least comparable to that of free daunorubicin. The aim of our study was to determine DNX pharmacokinetics in 11 poor-risk patients with acute leukemia treated with DNX 60 mg/m2 IV on days 1, 3, and 5. Blood and urine samples were collected at appropriate intervals after each of the three DNX administrations. The total amount of daunorubicin (free and entrapped) (t-DNR) and of its metabolite daunorubicinol (DNRol) was assayed by HPLC. The main pharmacokinetic parameters (t1/2alpha 4.54 +/- 0.87 h; VdSS 2.88 +/- 0.93 l/m2; Cl 0.47 +/- 0.26 l/h/m2) showed that in patients with acute leukemia liposomal-entrapped daunorubicin pharmacokinetics greatly differed from that observed for the conventional formulation. In fact, DNX produced mean plasma AUC levels (t-DNR AUC0-infinity 456.27 +/- 182.64 microg/ml/h) about 100- to 200-fold greater than those reported for the free drug at comparable doses due to a very much lower total body clearance. Volume of distribution at steady state was 200-to 500-fold lower than for the free drug. Plasma AUC of DNRol (17.62 +/- 7.13 microg/ml x h) was similar to or even greater than that observed with free daunorubicin for comparable doses. Cumulative urinary excretion showed that about 6% and 12% of the total dose of DNX administered was excreted in urine as daunorubicin and daunorubicinol, respectively. No major toxicity was encountered. Therefore, pharmacokinetic characteristics suggest that DNX may be more convenient than free daunorubicin in the treatment of acute leukemia. In fact, liposomal formulation may allow a reduction of daunorubicin captation in normal tissues. thus minimizing toxicity at least for the parent drug, and guarantee an unimpeded access to leukemic cells in the bloodstream and bone marrow, thus theoretically improving efficacy.
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Antibióticos Antineoplásicos/administración & dosificación , Antibióticos Antineoplásicos/farmacocinética , Daunorrubicina/administración & dosificación , Daunorrubicina/farmacocinética , Leucemia/tratamiento farmacológico , Enfermedad Aguda , Adulto , Anciano , Antibióticos Antineoplásicos/orina , Calibración , Daunorrubicina/orina , Portadores de Fármacos , Femenino , Humanos , Riñón/metabolismo , Liposomas , Masculino , Persona de Mediana Edad , Proyectos Piloto , Espectrometría de FluorescenciaRESUMEN
We analysed the expression of three drug transporter proteins [p-glycoprotein (PGP), lung resistance-related protein (LRP) and multidrug resistance-associated protein (MRP1)] involved in anthracycline resistance that are frequently overexpressed in poor-risk adult acute non-lymphocytic leukaemia (ANLL), in 23 acute promyelocytic leukaemia (APL) patients at onset managed at a single institution. Cellular daunorubicin accumulation was also evaluated. At onset, no case had PGP or MRP1 expression that exceeded that of non-multidrug-resistant (MDR) cell lines. Only one case showed LRP overexpression. No peculiar MDR features distinguished the seven patients who relapsed from those who maintained complete remission. In the onset vs. first relapse, only one patient showed an increased (threefold) PGP expression at relapse. At second relapse, three out of four patients showed a PGP expression two- to threefold higher than baseline values. These results are consistent with the view that low PGP, LRP and MRP1 expression and the absence of defects in intracellular drug accumulation may account for the peculiarly high sensitivity of APLs to anthracycline. It does not support the screening of MDR markers in APL patients at onset as predicting factors of early relapse. The results suggest that no significant changes in PGP, LRP or MRP1 expression are likely to occur at first relapse. In contrast, PGP expression is likely to increase later in the patient history as a result of additional chemotherapy courses.
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Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/metabolismo , Transportadoras de Casetes de Unión a ATP/metabolismo , Antibióticos Antineoplásicos/farmacología , Resistencia a Múltiples Medicamentos , Leucemia Promielocítica Aguda/metabolismo , Proteínas de Neoplasias/metabolismo , Partículas Ribonucleoproteicas en Bóveda/metabolismo , Adolescente , Adulto , Anciano , Daunorrubicina/metabolismo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Proteínas Asociadas a Resistencia a Múltiples Medicamentos , Recurrencia , Células Tumorales Cultivadas/metabolismoAsunto(s)
Antivirales/uso terapéutico , Trasplante de Células Madre Hematopoyéticas , Virus de la Hepatitis B/fisiología , Lamivudine/uso terapéutico , Activación Viral/efectos de los fármacos , Adulto , Hepatitis B/diagnóstico , Hepatitis B/prevención & control , Humanos , Masculino , Trasplante AutólogoRESUMEN
Reactivation of hepatitis B virus in patients receiving chemotherapy for non-Hodgkin's lymphoma (NHL) may give rise to hepatitis, hepatic failure and death, and prevent further chemotherapy. We report four patients with NHL in whom hepatitis flare-up was observed after two (three patients) and six (one patient) cycles of chemotherapy. After spontaneous recovery, they were treated with Lamivudine (100 mg/day), which enabled completion of chemotherapy without further hepatitis B reactivation. In one patient, high-dose chemotherapy and autologous stem cell transplantation was also performed. These data suggest a possible role for Lamivudine in preventing hepatitis B reactivation during chemotherapy administration to chronic carriers of the hepatitis B virus. Moreover, it enabled the completion of both standard and high-dose chemotherapy in patients with previous hepatitis B reactivation.
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Hepatitis B/complicaciones , Lamivudine/uso terapéutico , Linfoma no Hodgkin/tratamiento farmacológico , Inhibidores de la Transcriptasa Inversa/uso terapéutico , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Humanos , Linfoma no Hodgkin/complicaciones , Masculino , Persona de Mediana Edad , Activación ViralRESUMEN
BACKGROUND: Laparoscopic splenectomy (LS) is becoming the gold standard in the treatment of several splenic diseases. Shorter postoperative stay and more rapid return to full activity are the primary advantages of LS. METHODS: Prospective data collection of 44 consecutive LS (group 1) and comparison with a historical control group of 56 consecutive open splenectomies (OS) (group 2) were performed for hematologic diseases. RESULTS: The LS patients started earlier on an oral diet (p < 0.0001) and left the hospital sooner (p < 0.0002) than OS patients. Less blood transfusion (p < 0.004) and pain medication (p < 0.0001) was required by LS patients. They also had fewer postoperative complications (p < 0.03). Compared by diagnosis, patients with laparoscopic idiopathic thrombocytopenic purpura or Hodgkin's disease started to eat earlier (p < 0.0001) and left the hospital sooner (p < 0.01). Multivariate analysis showed that time to oral diet and postoperative stay was related to operative technique and age. Morbidity and pain medications were related, respectively, to transfusion requirements and type of surgical approach. CONCLUSIONS: Used to manage hematologic diseases, LS is feasible, effective, and safe. It offers several advantages over the open approach. The type of surgical approach seems to be the crucial factor in determining the length of the postoperative course.
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Enfermedades Hematológicas/cirugía , Laparoscopía/métodos , Esplenectomía/métodos , Adolescente , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Cuidados Posoperatorios , Estudios Prospectivos , Factores de RiesgoAsunto(s)
Daunorrubicina/administración & dosificación , Daunorrubicina/toxicidad , Composición de Medicamentos/métodos , Resistencia a Múltiples Medicamentos , Liposomas/administración & dosificación , Antraciclinas/administración & dosificación , Antraciclinas/toxicidad , Daunorrubicina/metabolismo , Humanos , Liposomas/metabolismo , Células Tumorales Cultivadas/efectos de los fármacosRESUMEN
The possibility that Daunoxome (DNX), a combination of daunorubicin (DNR) with a liposomal targeting system, escapes PGP was tested. Two pairs of leukaemic cell lines, each consisting of the parental non-multidrug resistance (MDR) line and of a MDR variant, were studied for cytotoxicity (MTT test) and for cellular DNR kinetic and accumulation (flow cytometry). DNX and free DNR were equally toxic against non-MDR cells, whereas the liposomal anthracycline was more toxic than the free drug against the MDR variant. Non-MDR cells accumulated DNR more rapidly when they were exposed to free DNR than to DNX, but MDR cells accumulated more DNR when they were exposed to DNX. The kinetics of DNX and free DNR were also studied in the blast cells of 41 cases of acute leukaemia and they were found to be related to blast cell PGP expression. In 15 cases with a low PGP expression intracellular DNR accumulation was faster and higher with free DNR than with DNX. In 26 cases with a high PGP expression the area under the curve was similar with DNX and free DNR, but the kinetics of intracellular DNR accumulation showed an early low plateau with free DNR and a slow and continuous increase with DNX. In MDR cell lines the ratio was more favourable to DNX than to free DNR. We conclude that liposome encapsulated DNR is partially protected from PGP and that it is worth testing for the treatment of PGP-positive acute leukaemia.
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Miembro 1 de la Subfamilia B de Casetes de Unión a ATP , Daunorrubicina/administración & dosificación , Leucemia/tratamiento farmacológico , Enfermedad Aguda , Daunorrubicina/farmacocinética , Portadores de Fármacos , Resistencia a Múltiples Medicamentos , Resistencia a Antineoplásicos , Ensayos de Selección de Medicamentos Antitumorales , Células HL-60 , Humanos , Leucemia/metabolismo , Liposomas , Células Tumorales CultivadasRESUMEN
OBJECTIVE: To determine the effect of the coadministration of the multidrug resistance (MDR) modulators cyclosporin A (CyA) alone or plus dexverapamil (D-Ver) on idarubicin (IDA) pharmacokinetics in patients with acute leukemia. METHODS: Pharmacokinetic studies were performed in 27 patients with a diagnosis of acute myelogenous leukemia (AML), who were being treated with a combination chemotherapy regimen including idarubicin and cytarabine for the induction of a first remission (n = 14), or of a second remission (n = 7), or for remission consolidation (n = 6). Of these 27 patients, nine were coadministered CyA and seven were coadministered CyA plus D-Ver as MDR modulators. Blood was sampled at appropriate intervals after each of the three IDA daily administrations. IDA and idarubicinol (IDAOL) were assayed by HPLC. Pharmacokinetic evaluations were performed by means of a two-compartment open model with zero-order absorption and first-order elimination using the WinNonlin pharmacokinetic software package. RESULTS: CyA markedly increased the area under the concentration time-curve (AUC) of both IDA [558.26 (197.25) microg x h x l(-1) vs 315.44 (158.28) microg x h x l(-1); P < 0.01] and IDAOL [2896.60 (736.38) microg x h x l(-1) vs 1028.49 (603.95) microg x h x l(-1); P < 0.001] when coadministered as a single modulator, due to a lower total body clearance (CL) [83.51 (52.44) l x h(-1) x m(-2) vs 139.65 (69.45) l x h(-1) x m(-2); NS]. When patients received two MDR modulators simultaneously (D-Ver plus CyA), IDA exposure was essentially the same as in those of the no inhibitor group [331.29 (95.49) microg x h x l(-1) vs 315.44 (158.28) microg x h x l(-1); NS], whereas the IDAOL total body exposure was greater than in the no inhibitor group [2030.32 (401.11) microg x h x l(-1) vs 1028.49 (603.95) microg x h x l(-1); P < 0.01], even if less than in patients receiving CyA as a single MDR modulator (IDA + CyA group) [AUC 2030.32 (401.11) microg x h x l(-1) vs 2896.60 (736.38) microg x h x l(-1); P < 0.05], suggesting an antagonistic effect against those of CyA on IDA and IDAOL elimination and/or an unpredictable redistribution. The main pharmacokinetic parameters of IDA, such as CL and volume of distribution at steady state (Vdss), were remarkably affected by the coadministration of CyA or CyA plus D-Ver, but no statistically significant difference was noted because of IDA pharmacokinetic interpatient variation. CONCLUSION: The results show that CyA alone at a dose of 10 mg x kg(-1) daily significantly increased systemic body exposure to both IDA and IDAOL in acute leukemia, and suggest that these pharmacokinetic effects were at least partially decreased when D-Ver was coadministered with CyA. Our findings raise important questions concerning the need for a dosage adjustment of IDA when MDR modulators are coadministered.
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Ciclosporina/farmacología , Resistencia a Múltiples Medicamentos/fisiología , Idarrubicina/farmacocinética , Leucemia Mieloide Aguda/tratamiento farmacológico , Verapamilo/farmacología , Ciclosporina/administración & dosificación , Quimioterapia Combinada , Humanos , Leucemia Mieloide Aguda/metabolismo , Factores de Tiempo , Verapamilo/administración & dosificaciónRESUMEN
P-glycoprotein (PGP), lung resistance-related protein (LRP) and multidrug resistance associated protein (MRP) expression and the blast cells' intracellular daunorubicin accumulation (IDA) were evaluated in 96 previously untreated cases of de novo acute non-lymphocytic leukaemia (ANLL). 47/96 patients (49%) were classified as PGP+ 44/ 96 (46%) as LRP+, and 8/96 (8%) as MRP+. The more frequent MDR clusters were PGP-/LRP-/MRP- (32/96 cases, 33%) and the PGP+/LRP+/MRP- (27/96 cases, 28%) followed by PGP+/LRP-/MRP- (15/96 cases, 16%) and PGP-/LRP+/MRP- (14/96 cases, 14%). A favourable karyotype was observed more frequently in PGP- and LRP-cases. A highly significant correlation was found between either PGP or LRP overexpression and leukaemic blast cell IDA. All the patients received standard induction and consolidation treatments containing MDR-related (idarubicin, mitoxantrone, etoposide) and other (arabinosyl cytosine) drugs. Multivariate analysis showed that PGP overexpression was significantly associated with a poor response to treatment, both in terms of primary resistance or shorter survival. Other independent prognostic factors were age and cytogenetics. LRP overexpression did not reach statistical significance, although for LRP+ cases the trend was unfavourable. Due to small numbers, no conclusion could be made regarding MRP overexpression, but 5/8 cases showed unfavourable karyotypic abnormalities, 8/8 had a defective IDA and 6/8 failed to achieve remission. This study showed that both PGP and LRP overexpression are common features in de novo ANLL at onset whereas MRP overexpression is more rare. It suggested that overexpression of one of the MDR related proteins was associated with a defective IDA, and confirmed that, in addition to age and cytogenetics, PGP retains an independent prognostic value. It also suggested that LRP did not affect clinical outcome when patients were treated with idarubicin or mitoxantrone and arabinosyl cytosine.
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Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/metabolismo , Genes MDR , Leucemia Mieloide Aguda/metabolismo , Proteínas de Neoplasias/metabolismo , Partículas Ribonucleoproteicas en Bóveda/metabolismo , Enfermedad Aguda , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Antineoplásicos/uso terapéutico , Aberraciones Cromosómicas , Femenino , Humanos , Cariotipificación , Leucemia Mieloide Aguda/tratamiento farmacológico , Leucemia Mieloide Aguda/genética , Masculino , Persona de Mediana Edad , Pronóstico , Tasa de SupervivenciaAsunto(s)
Trasplante de Células , Trasplante de Órganos , Bazo/inmunología , Donantes de Tejidos , Quimera por Trasplante , Adulto , Antígenos CD/análisis , Cadáver , Separación Celular , Supervivencia Celular , Femenino , Granulocitos/citología , Granulocitos/inmunología , Trasplante de Células Madre Hematopoyéticas , Humanos , Terapia de Inmunosupresión/métodos , Linfocitos/citología , Linfocitos/inmunología , Masculino , Persona de Mediana Edad , Monocitos/citología , Monocitos/inmunología , Bazo/citologíaRESUMEN
P-glycoprotein (Pgp)-related multidrug resistance (MDR) is frequently observed in acute non-lymphocytic leukemia (ANLL) and is associated with a poor response to standard chemotherapy. Cyclosporin A (CsA) is an effective downmodulator of Pgp-related MDR in vitro and has already been tested for that purpose in vivo also. Since Pgp is expressed in several normal cells and tissues, the modulation of Pgp can also modify total body exposure to antileukemic drugs and can alter and increase the toxicity of the antileukemic treatment. We report here the results of a study where 46 consecutive adult patients with ANLL were assigned to receive the same standard chemotherapy regimen of arabinosyl cytosine and idarubicin (IDA) for remission induction or consolidation, without or with CsA. Twenty-eight patients received 36 courses of chemotherapy without CsA and 18 patients received 32 courses of chemotherapy with CsA. CsA dose was 10-12.5 mg/kg/day and was given as a continuous i.v. infusion for 72 h. Whole blood CsA steady-state concentration ranged between 0.61 and 1.14 microM. The IDA area-under-the-curve was about twice as high in the cases that received CsA than in the other cases. CsA had no detectable effects on renal function and fluid balance, but significantly increased systemic blood diastolic pressure and conjugated bilirubine concentration. Furthermore, CsA-treated patients had greater, and more severe, oral and intestinal mucosal toxicity, with more severe adverse events, including more cases of gram-negative bacteremia, and with a delayed hemopoietic recovery. In conclusion, this study showed that an attempt at an effective downmodulation of Pgp-mediated MDR would substantially increase the hemopoietic and mucosal toxicity of antileukemic treatment and that the increase is accounted for, at least in part, by an increase of total body exposure to IDA.
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Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Ciclosporina/uso terapéutico , Leucemia Mieloide Aguda/tratamiento farmacológico , Adulto , Anciano , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Bilirrubina/sangre , Quimioterapia Adyuvante , Creatinina/sangre , Ciclosporina/efectos adversos , Citarabina/administración & dosificación , Estudios de Factibilidad , Femenino , Humanos , Idarrubicina/administración & dosificación , Idarrubicina/efectos adversos , Masculino , Persona de Mediana Edad , Inducción de Remisión , Resultado del TratamientoRESUMEN
BACKGROUND AND OBJECTIVE: In cell lines, there is an ongoing debate about the role of the lung resistance-related protein (LRP) whereas the role played by P-glycoprotein (PGP) in determining a multidrug resistance is well known. The aim of this study was to evaluate the frequency and the role of a PGP and an LRP overexpression in affecting the intracellular daunorubicin accumulation (IDA) and in predicting the therapy outcome on a subset of overt secondary acute non lymphocytic leukemias (ANLL). An adjunctive point was to evaluate the efficacy of the reversal agent SDZ PSC 833 (PSC) in counteracting impaired IDA. DESIGN AND METHODS: By flow cytometry, PGP and LRP expression and the IDA were evaluated on 54 overt secondary ANLL PGP and LRP overexpressions were respectively defined by an MRK-16 mean fluorescence index (MFI) > or = 6 (PGP+) and by an LRP-56 MFI > or = 5 i.e. by MRK-16 and LRP-56 MFIs higher than the one observed in normal leukocytes. The blasts' IDA was studied after a two-hour incubation in 1000 ng/mL daunorubicin in the presence or in the absence of the MDR reversal agent SDZ PSC 833 (PSC) 1.6 mumol. RESULTS: A PGP overexpression was detected in 40/54 (74%) cases while an LRP overexpression was observed on 33/54 (61%) cases. No differences were found in terms of PGP and LRP expressions between ANLL developing after chemo/radiotherapy (therapy-related ANLL) or evolving from a myelodysplastic syndrome (MDS-related ANLL). Compared to the PGP-, the PGP+ cases showed a significantly lower mean IDA (DNR NMFI 196 +/- 46 vs. 267 +/- 53, p < 0.001). The co-incubation of DNR with the PSC significantly increased only the mean IDA of the PGP+ cases, that grew from a DNR NMFI of 196 +/- 46 to a DNR NMFI of 284 +/- 67 (p < 0.0001). With respect to normal leukocytes, even the PGP- cases had an impaired IDA suggesting that other mechanisms, including an LRP overexpression, could affect the IDA. A strongly negative correlation was observed between PGP overexpression and therapy outcome, in fact, 8/10 (80%) PGP- but only 2/27 (7%) PGP+ patients obtained complete remission (p = 0.0002). Moreover, 7/33 (21%) cases showing an impaired IDA (NMFI < 280) but 4/4 (100%) with NMFI > 280 had complete remission (p = 0.006). No correlation was found between therapy response and LRP or CD34 expression. INTERPRETATION AND CONCLUSIONS: This data suggests that an important role in determining therapy outcome is played by PGP in secondary leukemias. Even if the LRP is frequently overexpressed in secondary leukemias and is likely to contribute to the reduction of the intracellular drug accumulation, the role played by LRP in determining the therapy-outcome has still to be cleared.
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Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/sangre , Leucemia Mieloide Aguda/diagnóstico , Proteínas de Neoplasias/sangre , Neoplasias Primarias Secundarias/diagnóstico , Partículas Ribonucleoproteicas en Bóveda , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/biosíntesis , Adulto , Anciano , Antígenos CD34/biosíntesis , Células de la Médula Ósea/química , Células de la Médula Ósea/citología , Células de la Médula Ósea/metabolismo , Línea Celular/metabolismo , Daunorrubicina/análisis , Daunorrubicina/uso terapéutico , Humanos , Líquido Intracelular/química , Leucemia Mieloide Aguda/tratamiento farmacológico , Leucocitos/química , Leucocitos/inmunología , Leucocitos/metabolismo , Persona de Mediana Edad , Proteínas de Neoplasias/biosíntesis , Pronóstico , Resultado del TratamientoRESUMEN
BACKGROUND AND OBJECTIVE: Anthracyclines are first-line drugs in the treatment of acute leukemia, but the sensitivity of leukemic cells to anthracyclines can be downmodulated by multidrug resistance (MDR) transport proteins like Pgp. Pgp overexpression is negatively related to treatment response. Alternative drugs may be required to overcome the MDR problem. METHODS: Arabinosylcytosine (ara-C) and 9-beta-D-arabinofuranosyl-2-fluoro-adenine monophosphate (fludarabine, F-ara) were tested alone and in combination in four pairs of leukemia and tumor non-MDR and MDR cell lines. Toxicity was assayed by growth inhibition with the microcultured MTT assay. RESULTS: MDR cells were more sensitive than or as sensitive as non-MDR cells to ara-C and to F-ara alone. The resistance index to ara-C was decreased upon pre-exposure of the MDR cells to low-dose F-ara (10 ng/mL), showing that the combination of ara-C and F-ara was more active on MDR cells than on non-MDR parental ones. INTERPRETATION AND CONCLUSIONS: Neither sensitivity to ara-C nor sensitivity to F-ara was influenced by Pgp overexpression. These data provide a rationale for more extensive and more intensive testing of combinations of ara-C and F-ara in Pgp-mediated MDR acute leukemia. In relapsed/resistant and in secondary acute leukemias, increasing the dose of ara-C and combining ara-C with F-ara might be more rewarding than administering anthracyclines or other Pgp-processable compounds.
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Antineoplásicos/farmacología , Citarabina/farmacología , Resistencia a Múltiples Medicamentos , Vidarabina/análogos & derivados , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Células Tumorales Cultivadas/efectos de los fármacos , Vidarabina/farmacologíaRESUMEN
P-glycoprotein (PGP) lung resistance protein (LRP) and multidrug resistance associated protein (MRP) expressions and function were evaluated by flow cytometry in 65 leukaemic patients (38 acute non-lymphocytic leukaemias, eight acute lymphocytic leukaemias, 19 Ph-positive chronic myeloid leukaemias in blastic phase). By using the MRK-16, the LRP-56 and the MRPm6 MoAbs, 34% of the cases did not over-express any proteins (-); 24.5% over-expressed (+) only PGP, 11% only LRP, 1.5% only MRP, 24.5% both PGP and LRP, and 4.5% both PGP and MRP. The mean intracellular daunorubicin accumulation (IDA) and rhodamine 123 (Rh123) retention in the presence or absence of the reversal agent SDZ PSC 833 (PSC) of the PGP-/LRP-/MRP- cases were comparable to the ones observed in normal leucocytes. With respect to the non-over-expressing cases, the PGP-/LRP+/MRP- cases showed only an impaired IDA (mean 204 +/- 29; P < 0.001). The PGP+/ LRP+/MRP- cases had a defect both in IDA (mean 166 +/- 47, P < 0.001) and Rh123 retention (mean 0.42 +/- 0.14: P < 0.001), which were both corrected by PSC. All the PGP+/LRP+/MRP- cases had a defect in IDA (mean daunorubicin (DNR) accumulation 192 +/- 44; P < 0.001). However, only in 8/16 of them an evident defect in Rh123 retention was found. In conclusion, both PGP and LRP over-expression were common in leukaemia. An impaired IDA was found in all cases over-expressing PGP, LRP or both. The study of Rh123 retention could give incorrect information about the blast cells' ability to accumulate cytotoxic drugs in patients over-expressing both PGP and LRP.