RESUMO
Apoptotic protease activating factor 1 (APAF-1) has a critical role in the regulation of apoptosis. In the present study, the mRNA expression analysis of different APAF-1 transcripts (APAF-1S, APAF-1LC, APAF-1LN, and APAF-1XL) was analyzed in bone marrow samples from 37 patients with acute myeloid leukemia (newly diagnosed, with no previous treatment). APAF-1XL and APAF-1LN transcripts (with and without an extra WD-40 repeat region, respectively) were detected in all samples, although the major form expressed was APAF-1XL in 65 percent of the samples (group 1), while 35 percent of the samples expressed primarily APAF-1LN (group 2). Only 46 percent of the patients presented complete remission in response to remission induction therapy (represented by less than 5 percent marrow blasts and hematological recovery), all but 2 cases being from group 1, 21.6 percent did not attain complete remission (only 1 case from group 1), and 32.4 percent of the patients died early. Lower expression of APAF-1XL (APAF-1XL/APAF-1LN ratio <1.2) was associated with a poor response to therapy (P = 0.0005, Fisher exact test). Both groups showed similar characteristics regarding white blood cell counts, cytogenetic data or presence of gene rearrangements associated with good prognosis as AML1-ETO, CBFB-MYH11 and PML/RARA. Since it has been shown that only the isoforms with the extra WD-40 repeat region activate procaspase-9, we suggest that low procaspase-9 activation may also be involved in the deregulation of apoptosis and chemotherapy resistance in acute myeloid leukemia.
Assuntos
Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Fator Apoptótico 1 Ativador de Proteases/genética , Leucemia Mieloide Aguda/genética , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Células da Medula Óssea/química , Estudos de Casos e Controles , Densitometria , DNA Complementar/genética , Regulação Neoplásica da Expressão Gênica , Leucemia Mieloide Aguda/tratamento farmacológico , Reação em Cadeia da Polimerase Via Transcriptase Reversa , RNA Mensageiro/genética , Fatores de Transcrição , Falha de Tratamento , Transcrição Gênica/genética , Biomarcadores Tumorais/genética , Adulto JovemRESUMO
We describe the clinical and molecular characteristics of two unrelated Brazilian families with an association of the Sicilian form of (deltaß)º-thalassemia with hemoglobin S and ß-thalassemia. Direct sequencing of the ß-globin gene showed only the hemoglobin S mutation in patient 1 and the ß-thalassemia IVS1-110 in patient 2. The other allele was deleted in both patients and PCR of DNA samples of the breakpoint region of both patients showed a band of approximately 1,150 bp, expected to be observed in the DNA of carriers of Sicilian (deltaß)º-thalassemia. The nucleotide sequence of this fragment confirmed the Sicilian deletion. There are few reports concerning the Hb S/(deltaß)º-thalassemia association and patient 2 is the first reported case of Sicilian type of (deltaß)º-thalassemia in association with ß-thalassemia documented at the molecular level