RESUMO
We examined the effect of the anthracyclines aclarubicin, bleomycin, daunorubicin, doxorubicin and idarubicin on human gamma- and beta-globin promoter activity in an in vitro luciferase assay, ex vivo in erythroid cultures and in vivo in transgenic mice carrying the human gamma-globin gene. Effects in erythroid liquid cultures derived from healthy donors were assayed by evaluating HbF production with high performance liquid chromatography and by measuring mRNA levels of the globin genes and the proportion of erythroblasts containing HbF. Compounds testing positive in the in vitro and ex vivo assays were applied to erythroid cultures derived from thalassaemic patients. Doxorubicin, idarubicin and daunorubicin increased HbF production in cultures of both, healthy and thalassaemic donors. Daunorubicin induced HbF in thalassaemic cells ex vivo with the highest statistical significance and, importantly and in contrast to the clinical HbF inducer hydroxyurea, showed specific induction of gamma-globin without associated induction of alpha-globin. Daunorubicin was screened in transgenic mice carrying the human (A)gamma-globin gene, and it resulted in increased (A)gamma-globin mRNA levels. Our results indicate that anthracyclines are a promising group of compounds with the potential to provide lead substances for the synthesis of new agents with clinical applications as gamma-globin gene inducers. In parallel, future studies of the epigenetic effects of the five anthracyclines on the beta-globin locus will generate possible mechanistic leads on the regulation of the globin genes.
