Microwave-assisted Synthesis Of Arene Ruthenium(â…¡) Complexes And Its Antitumor Mechanism

Studies on arene Ru（Ⅱ） complexes as novel antitumor agents have obtained alarge number of breakthroughs, a series of arene Ru（Ⅱ） complexes with highantitumor activity and low toxicity were reported, but the specific antitumormechanism of arene Ru（Ⅱ） complexes were still not clear. The importance of thisstudy is to utilize microwave-assisted synthesis technology to prepare a series ofarene Ru（Ⅱ） complexes, to evaluate the antitumor activity by MTT methods and toresearch the antitumor mechanism by molecular and cell biology methods.The results of this study are carried out as following:1) Microwave-assisted synthesis technology was used to prepare two dinucleararene Ru（Ⅱ） complexes:[（η⁶-1-R₁-4-R₄C₆H₄）RuCl₂]₂（a R₁=-H, R₄=-H; b R₁=-H,R₄=-CH₃; c R₁=-CH₃, R₄=-CH（CH₃）₂;） by1,3-cyclohexadiene and1-methyl-1,4-cyclohexadiene as raw materials. These25arene Ru（Ⅱ） complexeswere prepared by [（η6-1-R₁-4-R₄C₆H₄）RuCl₂]₂（a R₁=-H, R₄=-H; b R₁=-H, R₄=-CH₃;c R₁=-CH₃, R₄=-CH（CH₃）₂;） and phenanthroimidazole derivatives with the yield of>90%under microwave irradiation, and the structure of arene Ru（Ⅱ） complexeswere characterized by ESI-MS, IR,¹H NMR,13C NMR,¹H¹H COSY and X-raycrystal diffraction.2) Cytotoxicity induced by arene Ru（Ⅱ） complexes towards human cancer celllines and HK-2human normal renal cell were screened by MTT assay, with cisplatinand NAMI-A as positive comparison. Three complexes were identified as promisinganticancer agents with high anti-tumor activity equivalent to that of cisplatin andNAMI-A. Arene Ru（Ⅱ） complexes exhibited broad-spectrum antiproliferativeactivity against several human cancer cell lines, especially to MG-63and MCF-7 cells. Importantly, these complexes showed less cytotoxicity to human normal cells,indicating the splendid selectivity between human cancer cells and normal cells. Thestructure-relationship analysis of complexes was performed to discuss theimprovement of antitumor activity of arene Ru（Ⅱ） complexe smodified by differentelectron donating/deficient group in different position in phenanthroimidazolederivatives, and the results indicated that the complexes modified by electrondonating group exhibited better anti-tumor activity, meanwhile, the group inortho-position and para-position showed better anti-tumor activity than that of inmeta-position.3) Flow cytometric analysis, single-cell gel electrophoresis and westernblotting analysis were employed to examine antitumor mechanism induced by areneRu（Ⅱ） complexes. The results suggested that arene Ru（Ⅱ） complexes inducedMG-63cell cycle arrest in S phase by induction of DNA damage mediated-mediatedp53phosphorylation.4) Several spectroscopy methods were used to determine the interactionbetween arene Ru（Ⅱ） complexes and CT-DNA, and the results revealed that areneRu（Ⅱ） complex can bind with CT-DNA in a intercalating mode. Furthermore, thespectroscopy, ITC, PCR-stop and molecular docking analysis found that arene Ru（Ⅱ）complex can strongly interact with c-myc, a potential antitumor target, in a groovemode.