| Objective: This paper investagated the influence of curcumin onapoptosis-related gene expression and its ultrastructure change of prostatecancer cell line DU-145.Methods: The following methods were performed in the study toobserve the mechanism of curcumin to induce DU-145 cells apoptosis.1.CCK-8 was performed to observe DU-145 cell growth inhibition rate ofcurcumin with different concentrations, which were from 70 to120μmol·L-1, and cultured for 2 to 24h. 2.Agarose gel electrophoresis wasperformed to detect the oligonucleotide fragments (ladder band) formed byapoptotic DU-145 cells, which was cultured with curcumin for 24 hours.3.Flow cytometry techniques were performed to investigatecell apoptosisand cell cycle changes of DU-145 induced by curcumin. 4.Morphologychanges were observed through electron microscope to exhibit theinfluence of curcumin on DU-145 cell. 5. SP immunohistochemical assaywas performed to detect the expression of C-erbB-2, Bax, Bcl-2 andsurvivin of DU-145 cells Cultured with curcumin. Results: 1. Cell growthinhibition rate of curcumin DU-145 cells was cultured with curcumin ofdifferent concentrations (70,80,90,100,110,120μmol·L-1) for 6h to12h. With the increase of curcumin concentration, the inhibitory rateincreased from 5.0±1.0 to 41.9±2.3 in 6h group and from 40.5±2.3 to74.7±5.7 in 12h group. Difference between the groups wassignificant( P<0.01). 2. Agarose gel electrophoresis Marked DNA Ladderwas exhibited after culturing with curcumin for 24 hours, which indicatedthat curcumin induced DU-145 cell apoptosis. 3. Flow cytometry Apoptosis increased significantly in the 70μmol·L-1 curcumin group,which was more significant than that of control group ( P<0.05). With theincrease of concentration, the effect of apoptosis-inducing increaseddose-dependently. Curcumin significantly inhibited the proliferation ofDU-145 cells and clogged the cell cycle to G2/M phase.4. Morphologicchanges by electron microscope DU-145 cell processes disappearance,cell swelling, nuclear pyknesis and deep color were exhibited in70μmol·L-1 curcumin group after 6h and 12h culturation . Under theelectron microscope, microvilli disappeared. Cytoplasmic edema,ribosomes, mitochondria, lysosomes and endoplasmic reticulum reduced ordisappeared. Different chromosome numbered or the nucleus of apoptoticbodies was exhibited in DU-145 cells. 5. Immunohistochemical stainingThe expression of Survivin C-erbB-2 and Bcl-2 decreased in 70μmol·L-1curcumin group cultured for 6h to 48h. Over-expression of pro-apoptoticgene Bax increased. Difference between the groups was significant (P<0.01).Conclusion: Curcumin could inhibit prostate cancer DU-145 cellgrowth by directly damaging cellular ultrastructure and interfering with theapoptosis gene expression, which included reducing expression of Survivin,C-erbB-2, Bcl-2 and increasing expression of Bax. The cell cycle wasblocked to G2/M phase.
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