RESUMO
Ruthenium(II) complexes with 6-methyl-2-thiouracil cis-[Ru(6m2tu)2(PPh3)2] (1) and [Ru(6m2tu)2(dppb)] (2) (where PPh3 = triphenylphosphine; dppb = 1,4-bis(diphenylphosphino)butane; and 6m2tu = 6-methyl-2-thiouracil) are potent cytotoxic agents and able to bind DNA. The aim of this study was to evaluate in vitro cellular underlying mechanism and in vivo effectiveness of these ruthenium(II) complexes in human acute promyelocytic leukemia HL-60 cells. Both complexes displayed potent and selective cytotoxicity in myeloid leukemia cell lines, and were detected into HL-60 cells. Reduction of the cell proliferation and augmented phosphatidylserine externalization, caspase-3, -8 and -9 activation and loss of mitochondrial transmembrane potential were observed in HL-60 cells treated with both complexes. Cotreatment with Z-VAD(OMe)-FMK, a pan-caspase inhibitor, reduced Ru(II) complexes-induced apoptosis. In addition, both metal complexes induced phosphorylation of histone H2AX (S139), JNK2 (T183/Y185) and p38α (T180/Y182), and cotreatment with JNK/SAPK and p38 MAPK inhibitors reduced complexes-induced apoptosis, indicating DNA double-strand break and activation of caspase-mediated apoptosis through JNK/p38 pathways. Complex 1 also reduced HL-60 cell growth in xenograft model. Overall, the outcome indicated the ruthenium(II) complexes with 6-methyl-2-thiouracil as a novel promising antileukemic drug candidates.
Assuntos
Apoptose/efeitos dos fármacos , Complexos de Coordenação/farmacologia , Quebras de DNA de Cadeia Dupla/efeitos dos fármacos , Rutênio/farmacologia , Tiouracila/análogos & derivados , Animais , Caspases/metabolismo , Proliferação de Células/efeitos dos fármacos , Complexos de Coordenação/uso terapêutico , Feminino , Células HL-60 , Humanos , Leucemia Promielocítica Aguda , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Camundongos , Fosforilação/efeitos dos fármacos , Rutênio/uso terapêutico , Tiouracila/farmacologia , Tiouracila/uso terapêutico , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
This study determined the effects of thyroid hormone on the renal dopaminergic system. Surgical thyroidectomy (Tx) and treatment with 2-thiouracil (Thio) decreased renal cortex Na+/K+ ATPase activity and urinary volume. Tx also decreased urinary Na+ and urinary L-DOPA without changing urinary excretion of Dopamine (DA). Thio treatment decreased slightly urinary L-DOPA and Na+, but increased urinary excretion of DA. In both models of thyroid hormone deficiency, the ratio urinary DA/DOPA increased. Changes after Thio treatment were reversed after one month of drug withdrawal. Treatment with T3 via osmotic minipump increased Na+/K+ ATPase activity and urinary L-DOPA, did not change urinary DA, and increased the ratio DA/DOPA. To further analyze the effects of thyroid hormone deficiency, we administered selective DA1 (SCH-23390), DA2 (Sulpiride), and a non selective (Haloperidol) DA receptor antagonists to Thio treated and control animals. The DA1 antagonist decreased diuresis, natriuresis and urinary L-DOPA in control, but had no effect in Thio treated rats. Sulpiride had no effect in either group. The combination of SCH-23390 plus Sulpiride decreased urinary L-DOPA and urinary volume only in Thio treated animals. Haloperidol decreased urinary volume in Thio treated animals, but had no effect in controls. Our findings suggest that renal DA synthesis is to some extent dependent on thyroid hormone levels, and that the response of DA receptors is altered by thyroid hormone deficiency, indicating a role of this hormone in the regulation of the renal dopaminergic system.