Synthesis And Antitumor Activity Studies Of Ruthenium (Ⅱ) Polypyridyl Complexes

Three novel ligands and their eight ruthenium(II) polypyridyl complexes weresynthesized and characterized. The DNA-binding behaviors were investigated by UV/visspectra, fluorescence spectra, viscosity measurements and agarose gel electrophoresis. Thecytotoxicity in vitro, cellular uptake, apoptosis, reactive oxygen species, mitochondrialmembrane potential and western blot analysis were studied in detail. The apoptosis wasperformed with Hoechst33258and AO/EB staining methods. The cell cycle arrest wasinvestigated by flow cytometry. Mitochondrial membrane potential was assayed with JC–1as fluorescent probe. The reactive oxygen species were explored with DCFH-DA dying,and protein expressions were studied with western blotting analysis. For some tumour cells,these complexes display higher cytotoxic effect than cisplatin under identical condition.This paper is divided into five chapters.In the chapter1, the significance of this paper and the application of rutheniumcomplexes as anticancer drugs were stated. The research progress of antitumor activity ofthe ruthenium complexes and the way of cell death and the detection means of apoptosiswere stated. The interactive mode of ruthenium complexes with DNA was introduced andruthenium complexes are considered to be one of the most promising metal drugs.In chapter2, we synthesized a novel symmetric ligand and three complexes. Among ofthem, complex2d shows higher cytotoxic activity than cisplatin toward BEL-7402cells. The results obtained from UV/vis spectra, fluorescence spectra, viscosity measurementsand agarose gel electrophoresis experiments suggest that complex2d binds with DNA byintercalative mode. In addition, complex2d induce G0/G1phase arrest in BEL-7402cells.In chapter3, a new water soluble ligand containing two hydroxyl groups was prepared.The relative four Ru(II) complexes were synthesized and characterized by elementalanalysis, ES-MS and1H NMR. The antitumor activity of the four complexes wasinvestigated with AO/EB staining method, cellular uptake, and cell cycle arrest. It has beenfound that the four complexes show low cytotoxic activity. We analyzed the possiblereasons might be the poor fat-soluble of the four complexes made it difficult to be uptakenby cells. Among the four complexes, complex3c exhibits the highest antitumor activity.In chapter4, a new ligand and its complex were synthesized. Complex4a showshigher cytotoxic effect than cisplatin against several tumor cell lines under the sameconditions. The IC50of complex4a against BEL-7402, A549, MG-63cells are1.6±0.4,1.5±0.2,1.5±0.3μM, respectively. Complex4a can be uptaken by A549cells and thenmost of them accumulated in the nuclei. The results of western blotting analysis show thatcomplex4a could increase the levels of tumor inhibitor gene p53. In addition, the complex4a can inhibit the cell proliferation of A549cells at G0/G1phase arrest. Complex4a caninduce apoptosis of A549cells and increases the levels of reactive oxygen species, andreduces the mitochondrial membrane potential. the expression of Caspase-3, Caspase-7,Caspase-8were up-regulated, whereas the expression of procaspase-3, procaspase-7,procaspase-8were down-regulated, the levels of anti-apoptotic proteins including Bcl-2andBcl-x were decreased, and the expression of apoptosis proteins Bad and Bid were increased.In the chapter5, we analyze the possible reasons for complex4a to show highercytotoxic activity than cisplatin, and the applied prospect of the ruthenium complexes asantitumour drugs are implied.