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1.
Leuk Res ; 36(4): 397-400, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22177456

RESUMO

We studied a retrospective cohort of 282 higher-risk MDS treated with azacitidine, including 32 patients who concomitantly received an ESA for a median of 5.8 months after azacitidine onset. Forty-four percent of ESA and 29% of no-ESA patients reached HI-E (p=0.07); 48% and 20% achieved transfusion independence (p=0.01). Median OS was 19.6 months in the ESA and 11.9 months in the no-ESA groups (p=0.04). Addition of an ESA significantly improved OS (p=0.03) independently of azacitidine schedule and duration, and of our proposed azacitidine risk score (Blood 2011;117:403-11). Adding an ESA to azacitidine in higher-risk MDS should be studied prospectively.


Assuntos
Antimetabólitos Antineoplásicos/administração & dosagem , Azacitidina/administração & dosagem , Hematínicos/administração & dosagem , Síndromes Mielodisplásicas/tratamento farmacológico , Síndromes Mielodisplásicas/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco , Resultado do Tratamento
2.
Oncogene ; 31(30): 3536-46, 2012 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-22105358

RESUMO

Despite recent progress in the treatment of acute myeloid leukemia (AML), the prognosis of this rather heterogeneous disease remains poor and novel chemotherapeutics that specifically target leukemic cells must be developed. To address this need at the preclinical level, we implemented a high content imaging-based screen for the identification of small agents that induce AML cell death in vitro. Among a panel of 1040 Food and Drug Administration-approved agents, we identified pyrithione zinc (PZ) and ouabain (OUA) as potential antileukemic compounds. Both PZ and OUA efficiently induced cell death associated with apoptotic chromatin condensation and inhibition of nuclear factor-κB survival signaling, leading to reduced expression of antiapoptotic proteins, in several AML cell lines. PZ- and OUA-induced cell death was associated with the permeabilization of the outer mitochondrial membrane and led to the release of cytochrome c followed by caspase activation. Both PZ and OUA exerted significant anticancer effects in vivo, on human AML cells xenografts as well as ex vivo, on CD34(+) (but not CD34(-)) malignant myeloblasts from AML patients. Altogether, our results suggest that PZ and OUA may exhibit antileukemic effects by inducing the apoptotic demise of AML cells.


Assuntos
Antineoplásicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica , Leucemia Mieloide Aguda/tratamento farmacológico , Compostos Organometálicos/uso terapêutico , Ouabaína/uso terapêutico , Piridinas/uso terapêutico , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Cromatina/efeitos dos fármacos , Células Precursoras de Granulócitos/efeitos dos fármacos , Humanos , Camundongos , Camundongos Nus , Membranas Mitocondriais/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Resultado do Tratamento , Ensaios Antitumorais Modelo de Xenoenxerto
5.
Oncogene ; 28(22): 2205-18, 2009 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-19398952

RESUMO

The molecular mechanisms responsible for the evolution from the preleukemic entities of low-risk myelodysplastic syndrome (MDS) to the less favorable forms of high-risk MDS, as well as those enabling transformation to acute myeloid leukemia (AML), are still incompletely understood. Abundant evidence from solid tumors demonstrates that preneoplastic lesions activate signaling pathways of a DNA damage response (DDR), which functions as an 'anticancer barrier' hindering tumorigenesis. Testing the hypothesis that subgroups of MDS and AML differ with respect to DDR, we first assessed markers of DDR (phosphorylation of ATM, Chk-1, Chk-2 and H2AX) in cell lines representing different entities of MDS (P39, MOLM-13) and AML (MV4-11, KG-1) before and after gamma-irradiation. Although gamma-irradiation induced apoptosis and G(2)/M arrest and a concomitant increase in the phosphorylation of ATM, Chk-1 and H2AX in MDS-derived cell lines, this radiation response was attenuated in the AML-derived cell lines. It is noteworthy that KG-1, but not P39 cells exhibit signs of an endogenous activation of the DDR. Similarly, we found that the frequency of P-ATM(+) cells detectable in bone marrow (BM) biopsies increased in samples from patients with AML as compared with high-risk MDS samples and significantly correlated with the percentage of BM blasts. In contrast, the frequency of gamma-H2AX(+) cells was heterogeneous in all subgroups of AML and MDS. Whereas intermediate-1 MDS samples contained as little P-Chk-1 and P-Chk-2 as healthy controls, staining for both checkpoint kinases increased in intermediate-2 and high-risk MDS, yet declined to near-to-background levels in AML samples. Thus the activation of Chk-1 and Chk-2 behaves in accord with the paradigm established for solid tumors, whereas ATM is activated during and beyond transformation. In conclusion, we demonstrate the heterogeneity of the DDR response in MDS and AML and provide evidence for its selective suppression in AML because of the uncoupling between activated ATM and inactive checkpoint kinases.


Assuntos
Dano ao DNA , Leucemia Mieloide Aguda/genética , Síndromes Mielodisplásicas/genética , Proteínas Mutadas de Ataxia Telangiectasia , Biópsia , Medula Óssea/patologia , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Quinase do Ponto de Checagem 2 , Dano ao DNA/efeitos da radiação , Proteínas de Ligação a DNA/metabolismo , Células Precursoras de Granulócitos/efeitos dos fármacos , Células Precursoras de Granulócitos/metabolismo , Células Precursoras de Granulócitos/patologia , Células Precursoras de Granulócitos/efeitos da radiação , Histonas/metabolismo , Humanos , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/patologia , Síndromes Mielodisplásicas/metabolismo , Síndromes Mielodisplásicas/patologia , Fosforilação , Proteínas Serina-Treonina Quinases/metabolismo , Radiossensibilizantes/farmacologia , Proteínas Supressoras de Tumor/metabolismo
6.
J Chemother ; 19(5): 554-61, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18073155

RESUMO

Osteosarcomas (OS) are the most frequent primary malignant bone tumors in humans. Even though OS are chemosensitive, about 30% of patients must be considered poor responders and consequently have a dismal long term prognosis. The Hedgehog (Hh) gene is crucial in the signalling pathways of proliferation and differentiation during embryonic development. There is evidence that uncontrolled activation of this pathway results in specific types of cancer and that inhibition of Hh signalling is able to suppress tumour growth and to induce apoptosis of neoplastic cells. This study investigates the impact of the steroidal alkaloid and Hh-inhibitor cyclopamine on osteosarcoma cells. Thus we demonstrate the drug's impact on cellular proliferation, cell cycle cell death as well as the cells' metabolism. We here demonstrate that cyclopamine exhibits a high efficacy against the osteosarcoma cell lines HOS, SaOS and OS-KA, a self-established primary osteosarcoma cell line. In particular, cyclopamine is able to inhibit proliferation and to promote cell death. Our results provide evidence for the potency of the Hh-inhibitor cyclopamine as a future treatment of osteosarcomas.


Assuntos
Neoplasias Ósseas/tratamento farmacológico , Proliferação de Células/efeitos dos fármacos , Proteínas Hedgehog/efeitos dos fármacos , Osteossarcoma/tratamento farmacológico , Antineoplásicos , Linhagem Celular Tumoral , Criança , Relação Dose-Resposta a Droga , Feminino , Citometria de Fluxo , Humanos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Alcaloides de Veratrum
7.
Oncogene ; 26(28): 4071-83, 2007 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-17213804

RESUMO

CD34(+) bone marrow blasts from high-risk myelodysplastic syndrome (MDS) patients as well as MDS patient-derived cell lines (P39 and MOLM13) constitutively activate the nuclear factor-kappaB (NF-kappaB) pathway and undergo apoptosis when NF-kappaB is inhibited. Here, we show that the combination of conventional chemotherapeutic agents (daunorubicin, mitoxantrone, 5-azacytidine or camptothecin) with the NF-kappaB inhibitor BAY11-7082 did not yield a synergistic cytotoxicity. In contrast, BAY11-7082 (which targets the NF-kappaB-activating I-kappaB kinase (IKK) complex) or knockdown of essential components of the NF-kappaB system (such as the IKK1 and IKK2 subunits of the IKK complex and the p65 subunit of NF-kappaB), by small interfering RNAs sensitized MDS cell lines to starvation-induced apoptosis. The combination of BAY11-7082 and nutrient depletion synergistically killed the acute myeloid leukemia (AML) cell line U937 as well as primary CD34(+) bone marrow blasts from AML and high-risk MDS patients. The synergistic killing by BAY11-7082, combined with nutrient depletion, led to cell death accompanied by all hallmarks of apoptosis, including an early loss of the mitochondrial transmembrane potential, the release of cytochrome c and apoptosis-inducing factor (AIF) from mitochondria, activation of caspase-3, phosphatidylserine exposure on the plasma membrane surface and nuclear chromatin condensation. Transmission electron microscopy revealed the presence of numerous autophagic vacuoles in the cytoplasm before cells underwent nuclear apoptosis. Nonetheless, cell death was neither inhibited by the pan-caspase inhibitor z-VAD-fmk nor by knockdown of AIF or of essential components of the autophagy pathway (ATG5, ATG6/Beclin-1, ATG10, ATG12). In contrast, external supply of glucose, insulin or insulin-like growth factor-I could retard the cell death induced by BAY11-7082 combined with starvation. These results suggest that in MDS cells, NF-kappaB inhibition can precipitate a bioenergetic crisis that leads to an autophagic stress response followed by apoptotic cell death.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Morte Celular , Leucemia Mieloide/tratamento farmacológico , Síndromes Mielodisplásicas/tratamento farmacológico , NF-kappa B/antagonistas & inibidores , Nitrilas/uso terapêutico , Sulfonas/uso terapêutico , Doença Aguda , Imunofluorescência , Humanos , Leucemia Mieloide/patologia , Síndromes Mielodisplásicas/patologia
8.
Oncogene ; 26(16): 2299-307, 2007 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-17043643

RESUMO

In high-risk myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML), blasts constitutively activate the antiapoptotic transcription factor nuclear factor-kappaB (NF-kappaB). Here, we show that this NF-kappaB activation relies on the constitutive activation of the IkappaB kinase (IKK) complex, which is formed by the IKKalpha, IKKbeta and IKKgamma/NF-kappaB essential modulator (NEMO) subunits. A cell-permeable peptide that mimics the leucine zipper subdomain of IKKgamma, thus preventing its oligomerization, inhibited the constitutive NF-kappaB activation and induced apoptotic cell death in a panel of human MDS and AML cell lines (P39, MOLM13, THP1 and MV4-11). Small interfering RNA-mediated knockdown of the p65 NF-kappaB subunit or the three IKK subunits including IKKgamma/NEMO also induced apoptotic cell death in P39 cells. Cell death induced by the IKKgamma/NEMO-antagonistic peptide involved the caspase-independent loss of the mitochondrial transmembrane potential as well as signs of outer mitochondrial membrane permeabilization with the consequent release of cytochrome c, apoptosis-inducing factor and endonuclease G. Primary bone marrow CD34(+) cells from high-risk MDS and AML patients also succumbed to the IKKgamma/NEMO-antagonistic peptide, but not to a mutated control peptide. Altogether, these data indicate that malignant cells in high-risk MDS and AML cells critically depend on IKKgamma/NEMO to survive. Moreover, our data delineate a novel procedure for their therapeutic removal, through inhibition of IKKgamma/NEMO oligomerization.


Assuntos
Quinase I-kappa B/antagonistas & inibidores , Leucemia Mieloide/patologia , Síndromes Mielodisplásicas/patologia , Doença Aguda , Sequência de Aminoácidos , Apoptose , Linhagem Celular Tumoral , Humanos , Quinase I-kappa B/química , Quinase I-kappa B/genética , Dados de Sequência Molecular , NF-kappa B/fisiologia , Fragmentos de Peptídeos/química , Subunidades Proteicas , RNA Interferente Pequeno/genética , Transfecção
9.
Onkologie ; 24(2): 162-4, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11441297

RESUMO

BACKGROUND: Regarding standardization of treatment, classification, and pathophysiology of peripheral T- and NK-cell neoplasias the current knowledge is markedly behind that of B-cell lymphomas, which are approximately 10 times more frequent. In May 2000, the study group 'Peripheral T- and NK-cell Neoplasias' was founded in Frankfurt/M. This group decided on a clinical protocol and a scientific program for research on the pathophysiology of these entities. Rationales for the therapeutic regimen are the efficacy of cyclophosphamide and doxorubicine as shown in protocols for treatment of high grade lymphoma, the synergism of cyclophosphamide and fludarabine, and reports demonstrating the efficacy of fludarabine in T-cell neoplasias. PATIENTS AND METHODS: Patients will be treated with a combination of fludarabine (30 mg/m(2) days 1-3), cyclophosphamide (1000 mg/m(2) day 1) doxorubicine (25 mg/m(2) day 2+3) (FCD). For patients > or =65 years a dose-reduced FCD regimen will be administered. In patients included in the treatment study and additionally in patients with indolent disease not requiring therapy, scientific projects on the biology of peripheral T- and NK-cell neoplasias will be performed. CONCLUSIONS: Expected conclusions of the projected study are the establishment of treatment and diagnostic standards, and improvement of classification of these entities by clinical, morphologic and biologic parameters.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Células Matadoras Naturais , Linfoma de Células T Periférico/tratamento farmacológico , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Ciclofosfamida/administração & dosagem , Ciclofosfamida/efeitos adversos , Relação Dose-Resposta a Droga , Doxorrubicina/administração & dosagem , Doxorrubicina/efeitos adversos , Esquema de Medicação , Sinergismo Farmacológico , Feminino , Humanos , Células Matadoras Naturais/efeitos dos fármacos , Linfoma de Células T Periférico/classificação , Linfoma de Células T Periférico/imunologia , Masculino , Pessoa de Meia-Idade , Prognóstico , Resultado do Tratamento , Vidarabina/administração & dosagem , Vidarabina/efeitos adversos , Vidarabina/análogos & derivados
10.
Hematol J ; 2(2): 103-7, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11424002

RESUMO

INTRODUCTION: Prostate apoptosis response gene-4, known as par-4, is a new proapoptotic factor functionally required but not sufficient for apoptosis. Since there is evidence from prostate cancer cells that par-4 is involved in regulation of bcl-2 we assessed expression of par-4 and bcl-2 in different populations of normal and neoplastic lymphocytes. MATERIALS AND METHODS: Expression of par-4 mRNA and protein in different subpopulations of normal and neoplastic lymphocytes was assessed by reverse transcription polymerase chain reaction and Western blot. RESULTS: Par-4 mRNA was not detectable in lymphocytes of healthy volunteers (n = 10), but was present in the majority of samples of chronic lymphocytic leukemia (n = 30), chronic lymphocytic leukemia/prolymphocytic leukemia (n = 6) and acute lymphocytic leukemia (n = 10). Par-4 protein was expressed unanimously in samples of mononuclear cells from healthy volunteers and patients with CLL, but less frequently in immature lymphocytes, including neoplastic cells of CLL/PLL and ALL. The decreased frequency of par-4 expression in immature subpopulations was confirmed by results on lymphocytic cell lines at various stages of maturation. Comparing the expressional patterns of par-4 and bcl-2 there was an inverse relationship of both proteins in ALL and different lymphocytic cell lines, indicating a functional relationship of par-4 and bcl-2. CONCLUSIONS: This study establishes par-4 as a factor expressed in the majority of normal and neoplastic lymphocytic cells, demonstrating a decreased frequency of protein expression in less differentiated lymphocytes and an inverse expressional pattern of par-4 and bcl-2 in lymphocytic cell lines and ALL.


Assuntos
Diferenciação Celular , Regulação Leucêmica da Expressão Gênica , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Linfócitos/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/biossíntese , Proteínas Reguladoras de Apoptose , Feminino , Humanos , Células Jurkat , Leucemia Linfocítica Crônica de Células B/metabolismo , Linfócitos/patologia , Masculino
11.
Haematologica ; 86(5): 485-93, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11410411

RESUMO

BACKGROUND AND OBJECTIVES: Regulation of apoptotic cell death is being increasingly recognized as a mechanisms by which cytostatic agents mediate tumor cell death. Preliminary clinical studies with bendamustine, an alkylating agent with a purine nucleus, provide strong evidence that this drug is a highly effective cytostatic in low grade lymphomas. Therefore, we investigated the in vitro activity of bendamustine in combination with other established cytotoxic drugs. DESIGN AND METHODS: 2 lines (DOHH-2, WSU-NHL) and mononuclear cells (MNC) from patients with leukemic low-grade B-non-Hodgkin's lymphoma (NHL) (n=10), T-NHL (n=7) and chronic lymphocytic leukemia (CLL) (n=12). Apoptosis (7-AAD), depolarization of mitochondrial membrane potential (MMP, JC-1), caspase-3-activity (FIENA) and cell proliferation (XTT/WST-1) were determined. Several incubation times and drug dosages (for IC(30/50/75/90)) were studied. Synergistic, additive or antagonistic effects were calculated by a median plot effect and the combination index (CI) method. RESULTS: In general, combinations of bendamustine with mitoxantrone or doxorubicin resulted in antagonistic effects in the tested cell lines and the MNC from the patients. CI-calculation failed in these cases since there was not a sufficient dose response. On the other hand, the combination of bendamustine with 2-CdA showed synergistic in vitro activity on the tested cell lines, neoplastic lymphocytes from patients with peripheral T-cell lymphomas and partially on MNC from patients with CLL and B-NHL. The antagonism of the combination of bendamustine and anthracyclines appeared to be due to inhibition of depolarization of mitochondrial-membrane potential and caspase-3-activity during apoptosis of the studied cell lines. INTERPRETATION AND CONCLUSIONS: In conclusion, our results suggest that schedules using combinations of bendamustine and anthracyclines should not be recommended for the treatment of low-grade NHL, whereas bendamustine combined with 2-CdA could be considered for the development of future treatment strategies.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Apoptose/efeitos dos fármacos , Linfoma não Hodgkin/patologia , Compostos de Mostarda Nitrogenada/farmacologia , Compostos de Mostarda Nitrogenada/uso terapêutico , Cloridrato de Bendamustina , Interações Medicamentosas , Humanos , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Leucemia Linfocítica Crônica de Células B/patologia , Linfoma não Hodgkin/tratamento farmacológico , Células Tumorais Cultivadas/efeitos dos fármacos
12.
Br J Haematol ; 112(1): 201-3, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11167803

RESUMO

We describe a case of cytotoxic T-large granular lymphocyte leukaemia showing typical morphological features, expressing antigens characteristic for cytotoxic T cells and exhibiting marked natural killer-like cytotoxicity towards different target cells. Moreover, characterization of the T-cell receptors revealed simultaneous expression of two different types of beta-chains as well as alpha-chains by the malignant cell clone. The patient had an 8 year history of indolent disease, before progressing to an aggressive clinical course hardly responsive to chemotherapeutic treatment. This is the first description of a peripheral T-cell neoplasm expressing four distinct types of T-cell receptor molecules.


Assuntos
Rearranjo Gênico da Cadeia alfa dos Receptores de Antígenos dos Linfócitos T , Rearranjo Gênico da Cadeia beta dos Receptores de Antígenos dos Linfócitos T , Células Matadoras Naturais/imunologia , Leucemia de Células T/genética , Leucemia de Células T/imunologia , Receptores de Antígenos de Linfócitos T alfa-beta , Progressão da Doença , Citometria de Fluxo , Humanos , Infiltração Leucêmica , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Tempo
13.
Hematol J ; 2(6): 385-92, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11920278

RESUMO

INTRODUCTION: Acute promyelocytic leukemia (APL) patients with t(15;17)(PML/RARalpha positive) achieve remission upon t-RA treatment, whereas patients with t(11;17)(PLZF/RARalpha positive) do not. Both APL translocation products bind to the histone deacetylase (HD)-recruiting nuclear co-repressor complex (HD-NCR) in a ligand-dependent manner through their RARalpha portion. Differently to PML/RARalpha, PLZF/RARalpha also binds the HD-NCR in a ligand-independent manner through the PLZF portion of the fusion protein (PLZF#), which seems to be crucial for the t-RA resistance of t(11;17) APL patients. MATERIALS AND METHODS: The t-RA sensitivity of U937 cells was tested by the nitro-blue tetrazolium reduction (NBT) assay and by analysis of t-RA-induced type II transglutaminase activity. The interaction between HD-NCR and PLZF/RARalpha was investigated by in vitro binding assays. RESULTS: (i) Deletions in PLZF# convert PLZF/RARalpha from a repressor to an activator of t-RA response in U937 cells; (ii) the effect of PLZF/RARalpha on t-RA-signaling is regulated by the POZ-domain and its down-stream regions of PLZF#; (iii) there are additional binding sites for HD-NCR in PLZF# and (iv) PLZF# not only directly binds but also regulates the binding of PLZF/RARalpha to the HD-NCR. CONCLUSIONS: At least two different mechanisms responsible for the aberrant recruitment of HD-NCR complexes by PLZF# are regulating the different t-RA-sensitivity of the PLZF/RARalpha and PML/RARalpha positive APL blasts: one is related to the direct binding of the different members of the HD-NCR complex to PLZF#; the other is an enforcing effect of PLZF# on the affinity of the PLZF/RARalpha fusion protein to the HD-NCR complex.


Assuntos
Cromossomos Humanos Par 11 , Cromossomos Humanos Par 17 , Proteínas de Ligação a DNA/genética , Proteínas de Neoplasias/metabolismo , Proteínas de Fusão Oncogênica/metabolismo , Proteínas Repressoras/metabolismo , Fatores de Transcrição/genética , Translocação Genética , Proteínas de Ligação a DNA/fisiologia , Resistencia a Medicamentos Antineoplásicos , Histona Desacetilases/metabolismo , Humanos , Fatores de Transcrição Kruppel-Like , Leucemia Promielocítica Aguda/etiologia , Leucemia Promielocítica Aguda/genética , Mutação , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/farmacologia , Proteínas de Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/farmacologia , Proteína com Dedos de Zinco da Leucemia Promielocítica , Ligação Proteica , Proteínas Repressoras/fisiologia , Transdução de Sinais/efeitos dos fármacos , Fatores de Transcrição/fisiologia , Tretinoína/farmacologia , Células U937 , Dedos de Zinco/genética
14.
Ann Hematol ; 79(9): 485-92, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11043419

RESUMO

Induction of apoptosis in vitro using gemcitabine (dFdC) in combination with cladribine (2-CdA) and other cytotoxic drugs on malignant mononuclear cells (MNCs) of patients with acute myeloid leukemia (AML, n=20) and chronic lymphocytic leukemia (CLL, n =20) in myeloid (HL60, HEL) and lymphatic cell lines (HUT78, JURKAT) was investigated using different incubation conditions (simultaneous and consecutive). Furthermore, the influence of dFdC on the level of intracellular metabolites of 2-CdA was studied using high-performance liquid chromatography (HPLC). Apoptosis was evaluated using flow cytometry with 7-aminoactinomycin D. In MNCs of patients with CLL, dFdC + 2-CdA showed an antagonistic effect when applied simultaneously. This antagonism was reduced by consecutive application. The combination of dFdC with doxorubicin was synergistic, independent of incubation schedule. In blasts from newly diagnosed patients with de novo AML, all drug combinations (dFdC+2-CdA, doxorubicin, or cytosine arabinoside) were antagonistic by simultaneous incubation. Reduced antagonism or even synergism was shown (P<0.001) by consecutive incubation. The simultaneous combination of dFdC with 2-CdA in all tested cell lines resulted in a competitive inhibition on the rate of apoptosis. By changing the incubation period to a consecutive schedule, the antagonism was diminished or synergism of apoptosis was measured (P< 0.001). Using similar incubation conditions, these experiments were supported by HPLC measurement of intracellular metabolites of 2-CdA influenced by dFdC application. In conclusion, we demonstrated that the efficacy of dFdC in vitro in combination with other cytotoxic drugs depends on the incubation condition and on the origin of neoplastic cells (lymphatic vs myeloid). The data suggest that simultaneous combination therapy with purine and pyrimidine analogues may not improve the clinical efficacy of one or the other drug administered alone.


Assuntos
Antraciclinas/farmacologia , Antimetabólitos Antineoplásicos/farmacologia , Desoxicitidina/análogos & derivados , Desoxicitidina/farmacologia , Sistema Linfático/citologia , Células Mieloides/citologia , Apoptose/efeitos dos fármacos , Quimioterapia Combinada , Células HL-60 , Humanos , Células Jurkat , Leucemia Linfocítica Crônica de Células B/sangue , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Leucemia Linfocítica Crônica de Células B/patologia , Linfoma/sangue , Linfoma/tratamento farmacológico , Linfoma/patologia , Gencitabina
15.
Leuk Lymphoma ; 36(5-6): 559-67, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10784401

RESUMO

2-CdA is active as a single agent in the treatment of low-grade lymphomas. We analyzed the induction of apoptosis by 2-CdA alone (n=5) and in combination with other drugs in peripheral lymphocytes from 25 patients with leukemic low-grade lymphomas and from 25 healthy volunteers. 2-CdA was tested in 4 escalating concentrations (0.05 microg/ml to 0.4 microg/ml). Linear regressions showed a dose dependent apoptosis rate of 0.29 x microg 2-CdA/ml + 0.11 (r2=0.88, p=0.006) in normal cells and 0.41 x microg 2-CdA/ml + 0.15 (r2=0.88, p=0.005) in leukemic cells. Intracellular metabolization of 2-CdA into 2-CdA-5'mono-, -di- and the active metabolite -triphosphate was analyzed by HPLC and paralleled the dose dependent increase of apoptosis. The combination of 2-CdA with doxorubicin or mitoxantrone had a synergistic effect on the induction of apoptosis (p<0.001) in both normal and neoplastic lymphocytes, whereas 2-CdA plus etoposide or cytosine arabinoside were only additive. Due to the flat slope of the dose response of 2-CdA concentration on apoptosis we assume that higher in vivo dosages of 2-CdA in the treatment of low-grade lymphomas may not result in a higher clinical efficacy. The synergistic lymphocytotoxic effect of 2-CdA combined with doxorubicin or mitoxantrone may be relevant for new treatment approaches.


Assuntos
2-Cloroadenosina/análogos & derivados , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Desoxiadenosinas/farmacologia , Doxorrubicina/farmacologia , Linfoma/patologia , Mitoxantrona/farmacologia , 2-Cloroadenosina/farmacologia , 2-Cloroadenosina/uso terapêutico , Antineoplásicos/uso terapêutico , Desoxiadenosinas/uso terapêutico , Relação Dose-Resposta a Droga , Doxorrubicina/uso terapêutico , Sinergismo Farmacológico , Humanos , Linfoma/tratamento farmacológico , Mitoxantrona/uso terapêutico , Células Tumorais Cultivadas
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