Alterações lisossomais e indução de morte celular programada em celulas leucemicas tratadas com paladaciclo / Lysosomal alterations and programmed cell death induction in leukaemic cells treated with palladacycle

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Experimental studies involving the pharmaco-toxicogical properties of new drugs are of very importance in its initial development (ERDAL et al., 2005). In this study it was evaluated the possible antileukemic effects of a new organometallic class of drugs called palladacycle ferrocene 1:2, using the K562 and Jurkat leukaemia cell lines. The cell death mechanism of cytotoxicity induced by the Biphosphinic Palladacycle Complex (BPC) was studied using a K562 leukaemia cell line. The IC50% values obtained for K562 cells post 72 h of BPC were less than 5.0 µM by using MTT and trypan blue assays. Complex triggers apoptosis in K562 and Jurkat cells, inducing DNA fragmentation, as analysed through electrophoresis. Using the Acridine Orange (AO) vital staining combining fluorescence microscopy it was confirmed the presence these process in K562 cells. Lysosomal membrane permeabilization was also observed in K562 cells post 5 h of BPC, which suggests intralysossomal accumulation by proton-trapping, previous study, revealed that its pKa value ranged from 5.1 to 6.5. Caspase-3, and -6 activity induced by BPC in K562 cells was prevented by the cathepsin B inhibitor (CA-074). These events occurred in the presence of endogenous Bcl-2 and Bax expression. Taken together, these data suggest a novel lysosomal pathway for BPCinduced apoptosis, in which lysosomes are the primary target and cathepsin B acts as death mediator

ASSUNTO(S)

apoptosis k562 cell celulas k562 apoptose

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