RESUMO
BACKGROUND: Chronic myeloid leukemia (CML) is a clonal hematopoietic stem cell disorder associated with the activity of BCR-ABL fusion oncogene. Tyrosine kinase inhibitors are the current treatment of CML, but secondary mutations finally contribute to therapy resistance and blast crisis of the disease. The search for the novel compounds for the effective control of CML is now in the spotlight. The progression of CML to blast crisis is correlated with down-modulation of C/EBP alpha. Therefore, C/EBP alpha may be considered as a putative target in differentiation therapies in myeloid leukemias. The aim of the study was to assess the potential of vitamin E as the possible inducer of C/EBP alpha expression in BCR-ABL-positive CML K562 cells. MATERIALS AND METHODS: RNA extracted from K562 cells cultured with valproic acid or vitamin E was converted to cDNA, RT-PCR reactions were carried out using HotStarTaq DNA polymerase with primers for C/EBP alpha and granulocyte colony-stimulating factor receptor (G-CSFR). RESULTS: We have not found detectable expression of C/EBP alpha in K562 cells. Upon 48-h culture with vitamin E at a dose of 100 µM, K562 cells expressed both C/EBP alpha and G-CSFR. CONCLUSION: Vitamin E restored the expression of C/EBP alpha mRNA in chronic myelogenous leukemia K562 cells. In this setting, G-CSFR expression in vitamin E treated K562 cells seems to suggest the activation to granulocytic differentiation. It should be further elucidated whether such effects of vitamin E on C/EBP alpha transcription factor are direct or mediated indirectly due to antioxidant properties of vitamin E.
Assuntos
Antineoplásicos/farmacologia , Proteína alfa Estimuladora de Ligação a CCAAT/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Receptores de Fator Estimulador de Colônias de Granulócitos/genética , Vitamina E/farmacologia , Proteína alfa Estimuladora de Ligação a CCAAT/biossíntese , Linhagem Celular Tumoral , Proteínas de Fusão bcr-abl/genética , Regulação Leucêmica da Expressão Gênica , Humanos , Células K562 , Leucemia Mielogênica Crônica BCR-ABL Positiva/metabolismo , Receptores de Fator Estimulador de Colônias de Granulócitos/biossíntese , Ativação Transcricional/efeitos dos fármacos , Ácido Valproico/farmacologiaRESUMO
Ku protein is a multifunctional heterodimer of eukaryotes that consists of two subunits: Ku70 and Ku80. It plays a critical role in the regulation of many cellular processes such as: non-homologous end-joining, V(D)J-recombination of immunoglobulin genes and genes of T-cellular receptors, transcription regulation, DNA replication. Now the existence of relation between Ku protein functioning and processes that lead to transformation of normal cells into cancerous ones is determined, in Ph-positive leukemias and multiple myelomas, in particular. Nevertheless, the machinery of this processes is not still completely understood and needs further researches.
