ABSTRACT
The iron chelator deferasirox is widely used in patients with iron overload. Patients with low-grade myelodysplastic syndromes (MDS) get transfusion dependency and need to be treated with deferasirox to avoid iron overload. Moreover, in some patients an increase in both erythroid and platelets have been observed after deferasirox therapy. However, the mechanisms involved in these clinical findings are poorly understood. The aim of this work was to analyze, in patients treated with deferasirox, the changes in the gene-expression profile after receiving the treatment. A total of 15 patients with the diagnosis of low-grade MDS were studied. Microarrays were carried out in RNA from peripheral blood before and after 14 weeks of deferasirox therapy. Changes in 1457 genes and 54 miRNAs were observed: deferasirox induced the downregulation of genes related to the Nf kB pathway leading of an overall inactivation of this pathway. In addition, the iron chelator also downregulated gamma interferon. Altogether these changes could be related to the improvement of erythroid response observed in these patients after therapy. Moreover, the inhibition of NFE2L2/NRF2, which was predicted in silico, could be playing a critical role in the reduction of reactive oxygen species (ROS). Of note, miR-125b, overexpressed after deferasirox treatment, could be involved in the reduced inflammation and increased hematopoiesis observed in the patients after treatment. In summary this study shows, for the first time, the mechanisms that could be governing deferasirox impact in vivo.
Subject(s)
Deferasirox/therapeutic use , Erythropoiesis/drug effects , Gene Expression Profiling , Iron Chelating Agents/therapeutic use , Myelodysplastic Syndromes/drug therapy , Transcriptome/drug effects , Aged , Aged, 80 and over , Deferasirox/adverse effects , Erythropoiesis/genetics , Female , Gene Expression Regulation/drug effects , Gene Regulatory Networks/drug effects , Genome-Wide Association Study , Humans , Iron Chelating Agents/adverse effects , Male , Middle Aged , Myelodysplastic Syndromes/blood , Myelodysplastic Syndromes/diagnosis , Myelodysplastic Syndromes/genetics , Oligonucleotide Array Sequence Analysis , Pharmacogenetics , Treatment OutcomeABSTRACT
BACKGROUND: ß+-Thalassaemia is characterised by reduced production of ß chains, which decrease can be caused by mutations in the promoter region (CACCC or TATA box), and is classified as mild or silent depending on the extent of ß-globin chain reduction. In both cases, homozygotes or compound heterozygotes for these mutations usually have thalassaemia intermedia. Frequently the diagnosis is made in adulthood or even in old age. A total of 37 alterations in the promoter region have been described so far. AIMS: In this report we describe the mutations found in the promoter region of the ß-globin gene in a single hospital in Madrid. METHODS: Between 1998 and 2015, more than 9000 blood samples were analysed for full blood count and underwent haemoglobin electrophoresis and high performance liquid chromatography. Genetic analysis of the ß and Gγ-globin genes was carried out by automatic sequencing and, in the case of α genes, by multiplex PCR. RESULTS: 35 samples showed mutation in the promoter region of the ß-globin gene, with a total of six different mutations identified: one in the distal CACCC box, two in the proximal CACCC box, three in the ATA box. CONCLUSIONS: Any alterations in the proximal CACCC and TATA boxes lead to a moderate decrease in synthesis of the ß-globin chain, which has been demonstrated in cases of thalassaemia intermedia that have presented in the second decade of life with a moderate clinical course.
