Influence Of Autophagy And Apoptosis Induced With Curcumin On Three Cancer Cells

Objective:To investigate the molecular mechanisms of autophagy and apoptosis induced withcurcumin in different human cancer cell lines in vitro, including colon cancer cell(SW480), hepatoma carcinoma cell (HepG2) and gastric cancer cell (SGC7901).Methods:SW480, HepG2and SGC7901cells were cultured in vitro and treated with10,20,40,80μM of curcumin. The inhibitory effect of curcumin on their proliferation wasmeasured by MTT assay. The morphological alteration was observed by MDC andHoechst33342staining about autophagy and apoptosis. The apoptosis rates weredetermined by flow cytometry. The expression of NF-κB, LC3and Beclin1proteinslevels were detected by Western blotting analysis.Results:As the results shown, SW480, HepG2and SGC7901cells were all inducedapoptosis by curcumin in a dose-dependent manners, the viability of theses cells wasdecreased after treatment with10,20,40,80μM of curcumin. The IC50of curcuminwas approximately estimated to be40μmol·L-1for theses cells. After treated by40μMof curcumin, different degrees of autophagy and apoptosis emerged at12h and24h,which were measured by MDC and Hoechst33342staining. In the beginning, theautophagic vesicles in the cytoplasm of these cells were increased compared to the control group, which appeared bright green fluorescence under the microscope, butapoptotic features were unconspicuous. A few nucleus presented bright bluefluorescence. Although autophagic vesicles were still visible in these three cells in24h,apoptotic cells were increased obviously. In the course of autophagy and apoptosisinduced by curcumin, the autophagic stage is prior to executional stage of apoptosis.The results of FCM indicated that the apoptosis rate was increased in SW480, HepG2and SGC7901cells, from0.43to37.75%,0.33to40.2%,0.29to36.82%, respectivelywith the treatment of curcumin for24h. Western blot analysis showed that theexpression of protein NF-κB, LC3and Beclin1were all up-regulated at40μmol/L ofcurcumin treatment for12h and24h.Conclusion:1. It showed that curcumin could obviously cause growth inhibition of SW480,HepG2, SGC7901cells via a dose-dependent manner at the tested range ofconcentrations;2. Curcumin suppressing growth of SW480, HepG2, SGC7901cells may berelated with inducing autophagy and promoting apoptosis;3. NF-κB, LC3and Beclin1may be involved in autophagy and apoptosis inducedby curcumin.