Estudo do efeito de Deferoxamina, Curcumina e inibidor de ABL PD180970 sobre o ciclo celular e expressão gênica de linhagens leucêmicas

Abstract

Cancer is a disease that affects a large portion of the world population and has multiple causes, being directly related to the imbalance of genes involved in the regulation of cell differentiation and life cycle. This study evaluated the effect of deferoxamine, Curcumin and PD180970, an ABL nhibitor, on the cell cycle, viability and COX2 and CELF2 expression in K562 and U937 cell lines. Our initial hypothesis was that the deregulation of CELF2 gene in K562 and U937 cells could affect their life cycle. Its antagonic role on COX2 expression when pancreatic tumor cells were treated with curcumin led us to search microarrays databases for other substances that modify their ression. To understand the genomic structure of the promoter region we performed comparative genomic analyzes, a region of approximately 1000 bases upstream from the transcription start site of CELF2 gene preserved in 44 vertebrates, from non human primates to Danio rerio. This sequence was loned into the vector pCR-Bicolor,for fuetier analysis. Furthermore, flow cytometry assays and q-RT-PCR were performed which allowed us to observe that the CELF2 gene expression is not altered when and K562 cells were with treated Deferoxamine, curcumin and PD180970. However, these drugs altered the cell viability assays; curcumin caused a cell cycle arrest in G2/M phase after 24 hours of treatment, as well as decreased the viability in K562 cells treated after 24 hours at concentrations of 25 mM and 12.5mM. The ABL inhibitor PD180970 only exhibited reduced viability after 48 hours of treatment in 5 mM and 10 mM concentrations. q-RT-PCR experiment showed a statistical ecrease in the expression of COX2 gene in U937 cell line treated with DFO and Curcumin. These data owing decreased expression of COX-2 gene are new for leukemic cells treated with the used drugs and are independent of changes in the expression of CELF2 gene. At the same time, our data uggest that CELF2 expression induced by treatment with Curcumin is a cell-specific event, and would not apply to hematopoietic lineages.