A Novel Schiff Base Ruthenium Coordination Compound Inhibits The Proliferation And Induces Apoptosis Of Carcinoma Of Colon

Cisplatin had attracted special attention since its anticancer activity was discovered.From then on,people began to turn their attention to these metal-based anticancer drugs.New platinum drugs were kept developing and have achieved obviously efforts in clinical cancer treatment.However,accompanying the success of platinum,problems kept coming out,such as severe side effects and drug resistance,which encourage scientists to explore new solutions to overcome these defects.As a substitute for platinum,ruthenium was a potential material for antitumor drugs because of its specific structural characteristics.Ruthenium has been shown low toxicity and effective on cisplatin-resistant cells.These advantages make people keep spare more effort on Ruthenium research.Some Ruthenium complexes even have entered the phase II clinical trial.It won't be long that Ruthenium complexes can be used as an anti-tumor agent in clinical treatment.In the first part of this study,a novel Schiff base ruthenium complex(SBRCC)was synthesized.The cytotoxicity and effort on tumor cell proliferation of SBRCC were studied with cell lines in vitro using MTT assays.The IC50 of SBRCC on colon cancer cell line HCT-116 was 11.09 umol/L.Different DMSO concentration was used to discriminate the potential cytotoxicity of DMSO.A DMSO concentration less than 1% was considered safe on cell growth.The LC50 of SBRCC was 15.85mg/kg after corrected by Karber method.Then mice were treated with different concentrations of LC50,their mental status,diet,and death rate were collected after treatment.The pathological of the important organ was also studied.SBRCC showed less toxic and less visceral damage in mice experiments.In the second part,the inhibitory effect of SBRCC on HCT-116 proliferation was further studied.Apoptosis assays and the cell cycle analysis of HCT-116 cell line of SBRCC treatment was measured by Flow cytometry.It was shown that the inhibition of SBRCC on cell proliferation was time-dependent.The cell cycle of HCT-116 was arrested in G1 phase.The reduction of size and number of tumor clone after SBRCC treatment were also showed time-dependent using tumor colony forming assays.Apoptosis assay using AO-EB and Hoechst33258 staining fund that SBRCC could induce the apoptosis and membrane damage in HCT-116 cell lines.In the final part,we further explored the mechanism of SBRCC induced apoptosis in HCT-116 cell line.In the second part,we found that SBRCC could lead to membrane damage of HCT-116 cells,so we detected the death receptor pathway and protein expression of mitochondrial apoptotic pathway respectively.The results of Western and Blot showed that the expression of Fas and Fas-L increased with time prolonging,the expression of Bax also increased,which is apoptosis promoted,while the expression of apoptosis inhibitor Bcl-2 decreased.Meanwhile,SBRCC could also increase the expression of p53,which could be inhibited by p53 inhibitor.Whether autophagy-induced cell apoptosis in HCT-116? Firstly,with clone formation experiment,we found that the number of colony formation was increased by autophagy inhibitor.In the following western blot assay,this result was confirmed by the expression alteration of the autophagy-specific protein Beclin-1,LC3-II,and LC3-I.To further clarify the relationship among autophagy,p53,and apoptosis,p53 inhibitor Pifithrin-? was used in the following experiment.It was showed that Pifithrin-? could inhibit the expression of the autophagy-related protein and SBRCC induced autophagy.Autophagy inhibitor 3-MA could also inhibit SBRCC induced apoptosis by inhibiting autophagy progress.This demonstrated the role of p53 in promoting autophagy progression.In summary,we have found a novel Schiff base ruthenium(SBRCC)complex with a relatively low cytotoxicity,which could inhibit the proliferation of HCT-116 colon cancer cells.The mechanism of SBRCC inhibited apoptosis was partial via the death receptor and mitochondrial apoptosis pathway.P53 played an important role in this progress,which could promote apoptosis progression.Meanwhile,SBRCC could induce autophagy in HCT-116 cell line.P53 also took part in the progress of autophagy.Apoptosis rate reduced by inhibiting autophagy.Our work provided a new mechanism of ruthenium complex on cancer treatment.