The Gene RUNX1 and Its Possible Relation with the Alteration of Granulocytes Cells and with the Progression of Chronic Myeloid Leukemia.

Abstract 2215

Poster Board II-192

The exact action mechanism of the protein BCR-ABL is unknown, studies in vitro and in animal models showed that the activity of protein tyrosine kinase (TK), by itself, is sufficient to cause the development of CML. Thus, the progression of the disease to accelerated phase or blast crisis may be associated with genomic instability. The use of methods to detect the difference in gene expression between CML and normal granulocytes could bring new insights in the understanding of these complex mechanisms, highlighting new therapeutic targets for the CML treatment. Evaluation of the differential gene expression between CML and normal granulocytes using the Subtractive Suppression Hybridization (SSH) and investigation of the involvement of a set of genes in modulating the development of CML. The SSH libraries were constructed using a pool of granulocytes RNA's extracted from CML patients and from healthy blood donors. Real-Time (RT-PCR) was used to validate the results and evaluation of gene expression in granulocytes and in mononuclear cells in the pool of patients and controls used for the construction of libraries. The expression of the RUNX1 gene, whose expression was the most differential between the libraries, was evaluated in mononuclear cells of patients with CML using RT-PCR. The comparison between granulocytes of CML patients and control granulocytes showed 39 genes exclusively expressed in CML and 169 genes in controls. For validation, we evaluated the expression of genes RUNX1, KPNA6, TOB1, SEPT5, CDC42SE, ITCH, MIER and GP1BA by RT-PCR in the pool of patients and controls used for the construction of libraries. Among these genes, the RUNX1 gene showed substantial difference, and was also studied in mononuclear cells from 20 patients with CML in different stages of the disease and using different types of treatment with TK inhibitors. The expression of this gene was highly altered in patients in advanced phase of disease when compared with patients who are responding to treatment. The genes identified in this study may be related to the development and progression of CML. Among them, the RUNX1 gene was shown to be one of the most promising, since the occurrence of chromosomal translocations in this gene has been associated with different types of acute leukemia – however its association with CML is not yet clear. The results showed a relationship between the expression of this gene and progression of the disease, beyond the identification of several genes that may lead to a better understanding of CML and help in identifying new therapeutic targets. This work was supported by FAPESP.