RESUMEN
OBJECTIVES: Acute lymphoblastic leukemia (ALL) is a clonal disease that accounts for 20% of acute leukemias in adults. A high percentage of adult patients (ranging from 70 to 80%) reach complete remission; however, the 5-year survival rate is only 20-40%. One of the main obstacles to treatment success is the drug resistance of leukemic cells. Therefore, our research group analyzed the ABCB1 and ABCG2 gene expression levels in 61 patients diagnosed with ALL and assessed whether the levels affected the clinical parameters and 40-month survival rate. METHODS: The ABCB1 and ABCG2 gene expression levels were analyzed using real-time polymerase chain reaction in 61 patients diagnosed with ALL and 99 healthy donors as controls. The association between ABCB1 and ABCG2 gene expression levels and clinical variables was determined using the Chi-square test and Fisher's exact test. Overall survival (OS) was determined using the Kaplan-Meier method. RESULTS: The results showed high ABCB1 and ABCG2 gene levels, which were 4.5 and 2.3 times the levels of healthy donors, respectively. A total of 52% of the study patients expressed high ABCB1 levels and were significantly associated with the high-risk patient group and a decreased 40-month survival rate of 78%. Only 49% of the patients expressed high ABCG2 gene levels. No association was found between the clinical parameters and the ABCG2 gene expression levels. CONCLUSIONS: Early detection of ABCB1 gene expression levels could be important for the diagnosis and monitoring of ALL patients.
Asunto(s)
Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 2/biosíntesis , Regulación Neoplásica de la Expresión Génica , Proteínas de Neoplasias/biosíntesis , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras/mortalidad , Subfamilia B de Transportador de Casetes de Unión a ATP/biosíntesis , Adolescente , Adulto , Supervivencia sin Enfermedad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Tasa de SupervivenciaRESUMEN
Leukemia-associated antigens such as proteins encoded by MAGE genes might provide tools for immunotherapy of leukemia. Positive and negative results of MAGE-A gene expression in hematological malignancies have been reported. This led us to study MAGE-A gene expression in human leukemias using RT-PCR. Among 115 leukemias from various subtypes, 14/34 (41.17%) AML were positive for one of the three genes analyzed (MAGE-A1 1/32; MAGE-A3 10/32; MAGE-B2 3/12). Expression was also detected in 23/76 (30.26%) B-cell ALL patients (MAGE-A1 2/53; MAGE-A3 20/53; MAGE-B2 1/32). One of these patients expressed both MAGE-A1 (weak signal) and -A3 (strong signal) genes. Other patient with CML were positive for MAGE-B2 (1/5, 20%). MAGE-A3 expression data were corroborated by real time RT-PCR through determination of MAGE-A3 transcript levels. We concluded that the MAGE-A3 gene is expressed at the mRNA level in a proportion of human leukemias.
Asunto(s)
Antígenos de Neoplasias/genética , Leucemia/genética , Proteínas de Neoplasias/genética , ARN Mensajero/genética , Transcripción Genética , Adulto , Antígenos de Neoplasias/sangre , Secuencia de Bases , Cartilla de ADN , Femenino , Amplificación de Genes , Humanos , Leucemia/sangre , Leucemia Mielógena Crónica BCR-ABL Positiva/genética , Leucemia Mieloide Aguda/genética , Masculino , Persona de Mediana Edad , Proteínas de Neoplasias/sangre , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
The physical state of the human papillomavirus (HPV) genome is usually different in malignant lesions of the skin, in which it is generally found in episomal form, and genital mucosa, in which it is frequently integrated with disruption of the E2 gene. Using chimeric or natural HPV promoters in the presence of the bovine papillomavirus type 1 E2 gene product, we observed transcription activation or repression, depending on the distance of E2-binding motifs from the start site. We found a clear difference in the positions of E2-binding motifs in cutaneous and genital HPVs that may partly explain the selective pressure for genome integration of genital HPV types in malignant lesions.
Asunto(s)
Papillomavirus Bovino 1/genética , Proteínas de Unión al ADN/metabolismo , Regulación Viral de la Expresión Génica , Papillomaviridae/genética , Regiones Promotoras Genéticas , Transactivadores/metabolismo , Proteínas Virales/metabolismo , Secuencia de Bases , Línea Celular , Condiloma Acuminado/microbiología , ADN Viral , Células HeLa , Humanos , Datos de Secuencia Molecular , Verrugas/microbiologíaRESUMEN
Simian Virus 40 (SV40) DNA replication is a useful model to study eukaryotic cell DNA replication because it encodes only one replication protein and its genome has a nucleoprotein structure ('minichromosome') indistinguishable from cellular chromatin. Late after infection SV40 replicating DNA molecules represent about 5% of total viral minichromosomes. Since gene 32 protein (P32) from bacteriophage T4 interacts with single-stranded DNA and SV40 replication complexes are expected to contain single-stranded regions at the replication forks, we asked whether P32 might be used to isolate replicating SV40 minichromosomes. When nuclear extracts from SV40 infected cells were treated sequentially with P32 and anti-P32 antibodies, pulse-labeled minichromosomes were selectively immunoprecipitated. Agarose gel electrophoresis analysis confirmed that immunoprecipitated material corresponded to SV40 replicative intermediates. Protein analysis of the pelleted material revealed several proteins of viral and cellular origin. Among them, T antigen and histones were found to be complexed with at least other three proteins from cellular origin, to the replicative complexes. Additionally, anti-P32 antibodies were able to detect three cellular proteins of approximately 70, 32 and 13 kDa in western blots. These proteins could correspond to those found as part of an eukaryotic multisubunit single-stranded DNA binding protein. The use of P32 and anti-P32 antibodies thus allows the separation of replicating from mature SV40 minichromosomes and can constitute a novel method to enrich and to study replicative active chromatin.