| BackgroundStudies have shown that curcumin has an anti-tumor effect in several solid human tumors,and Wnt/?-catenin signaling plays important roles in the regulation of chemosensitivity of cancers.In the present study,we aim to determine the anti-tumor effects of curcumin in colon cancer cells(CRC),and to investigate the possible mechanisms in which curcumin enhances chemosensitivity of CRC to 5-Fluorouracil/Cisplatin(5-FU/DDP).Objectives(1)To determine the anti-tumor effects of curcumin in colon cancer cells in vitro;(2)To investigate the roles of curcumin in the regulation of chemosensitivity of CRC to 5-FU/DDP,and the underlying mechanisms in which curcumin regulates the chemosensitivity of CRC to 5-FU/DDP in vitro.Methods(1)Human colon cancer cell line SW480 and SW620 were cultured in vitro with the presence of concentrations at various concentrations(5 ?M,10?M,20 ?M,40?M)for 24 h and 48 h.Cell proliferation was detected using MTT assay,and the relative inhibition rate was also calculated;Flow cytometry was performed for the analysis of cell apoptosis;Cell invasion and migration abilities were detected by Transwell and scratch assay,respectively;Western-blot assays were conducted to measure the expressions of apoptosis-related proteins including Bax,Bcl2 andCaspases.(2)SW480 and SW620 cell lines were cultured with curcumin,and were treated with or without the presence of 5-FU or DDP.Cell proliferation was measured by MTT assay;t Flow cytometry was performed for the analysis of cell apoptosis;Cell invasion and migration abilities were detected by Transwell and scratch assay,respectively;Western-blot assays were conducted to measure the expressions of apoptosis-related proteins including Bax,Bcl2 and Caspases.The expression levels of Wnt/?-catenin signaling pathway-related proteins Axin,?-catenin,EpCAM,TERT and DCAMKL-1 were measured using western-blot assay.Results(1)Colon cancer cell lines SW480 and SW620 were treated with curcumin at various concentrations for 24 h and 48 h.MTT results showed that cell proliferation was significantly lower in the curcumin-treated groups as compared with the control group(p<0.05).Curcumin inhibited cell proliferation in a time-and concentration-dependent manner.IC50 values were calculated based on the results of proliferation inhibition rate.The results showed that the IC50 values of SW480 cells were 36 and 15 ?M at 24 and 48 hours after treatments,while in SW620 cells were 34 and 13 ?M,respectively.The difference in IC50 values between the two cell lines were insignificant(p>0.05).Flow cytometry showed that the population of apoptotic cells were significantly increased by the treatments of curcumin as compared with the control group(p<0.05).In addition,cell invasion and migration abilities were also inhibited by curcumin in a time-and dose-dependent manner(p<0.05).Western-blots showed that treatment with curcumin(IC50)significantly decreased the expression of Bcl-2 and increased the expression of Bax,Caspase-3,Caspase-8 and Caspase-9(p<0.05,respectively).(2)SW480 and SW620 cells were cultured with curcumin,and treated with or without the presence of 5-FU/DDP for 24 h and 48 h.Our results showed that cell proliferation rate in the Curcumin + 5-FU and Curcumin + DDP groups were significantly lower than that in the Curcumin,5-FU and DDP groups in both SW480 and SW620 cell lines(p<0.05,respectively);In addition,the combination of curcumin and 5-FU/DDP significantly increased cell apoptosis as compared with the Curcumin,5-FU and DDP groups(p<0.05,respectively).Similar changes in cell invasion and migration abilities have been also observed in both SW480 and SW620 cell lines.Importantly,the expression of Axin was significantly increased in the combination group as compared with the single drug-treated groups(p<0.05,respectively).On the other side,the expression levels of ?-catenin,EpCAM,TERT,and DCAMKL-1 were significantly decreased after co-treatments of curcumin and 5-FU/DDP as compared with the Curcumin,5-FU and DDP groups(p<0.05,respectively).Conclusions(1)In vitro study confirmed the anti-proliferation and cell toxicity abilities in colon cancer cells.Curcumin was able to inhibit cell invasion and migration abilities,and to promote cell apoptosis.(2)Curcumin enhanced chemosensitivity of colon cancer cells to 5-FU/DDP in vitro possibly through inhibiting Wnt/?-catenin signaling pathway. |
PDF Full Text Request