ABSTRACT
Background Our previous study showed that curcumin suppresses the proliferation of human lens epithelial cells (LECs) in vitro and has an influence on the signal transduction of cyclic adenosine monophosphate (cAMP) and cyclic guanosinc monophosphate (cGMP).Actually,the regulation for biological behavior of LECs in vivo is complex.Objective This study was to investigate the changes of signal transduction of protein kinase (PK) in inhibition of curcumin on human LECs proliferation.Methods HLE-B3 was cultured and then divided into the blank control group,recombinant human basic fibroblast growth factor (rhbFGF) group and rhbFGF+ curcumin group.rhbFGF of 10 ng/ml was added in the medium in the rhbFGF group,and 20 mg/L curcumin was added into rhbFGF-induced cell medium for 24 hours in the rhbFGF+ curcumin group.The expression rates of PKA,PKC,PKG and calmodulin (CaM) in the cells were assayed using flow cytometry.Results The expression rates of PKA protein were (46.847± 1.673) ％,(33.250 ± 2.242) ％ and (71.645 ±2.432) ％ in the blank control group,rhbFGF group and the rhbFGF+ curcumin group,respectively,and the expression rate of PKA protein was significantly reduced in the rhbFGF group compared with the blank control group (t =11.904,P＜0.01),but the expression rate of PKA protein in the rhbFGF+ curcumin group was significnatly higher than that in the rhbFGF group (t=28.430,P＜0.01).In the blank control group,rhbFGF group and the rhbFGF+ curcumin group,the expression rates of PKC protein in the cells were (35.575± 1.937) ％,(50.652±2.068) ％ and (27.662t4.481) ％,those of PKG protein were (63.838±0.486) ％,(86.562 ± 1.325) ％ and (40.733 ± 2.175) ％,while those of CaM protein were (67.408± 1.391)％,(83.887±3.499)％ and (53.785 ± 1.942)％,the expression rates of PKC,PKG and CaM were significantly lower in the rhbFGF group in comparison with the blank control group (all at P＜0.01),and those in the rhbFGF+ curcumin group were significantly declined in comparison with the rhbFGF group (all at P＜0.01).Conclusions Suppression of curcumin on HLE-B3 proliferation probably is associated with the up-regulation of PKA expression and down-regulation of PKC,PKG and CaM expression in the cells.
ABSTRACT
Objective To suppress the proliferation of lens epithelial cells (LECs) is a primary goal in prevention of after cataract. Recent study demonstrated an effective inhibition of elemene(Ele) on tumor cells. Present study was to investigate the effects of Ele on proliferation and cell cycle of human LECs B3 (HLE-B3). Methods Recombinant human basic fibroblast growth factor(rhbFGF) was utilized to induce proliferation of HLE-B3. Proliferative HLE-B3 was incubated with 80 mg/L Ele in CO_2 incubator for 24 hours. Then the inhibitory effects of Ele on proliferation of HLE-B3 was evaluated by methyl thiazolyl tetrazolium(MTT). The effect of Ele on HLE-B3 morphology was observed under the optical microscope. The effect of Ele on HLE-B3 cell cycle was analyzed by flow cytometer(FCM). Results MTT test showed that the optical density (OD) value of rhbFGF group was remarkably higher than that of control group(0. 599 0 ± 0. 053 1 versus 0. 409 1 ± 0. 042 2) (P ＜ 0. 01), and that of Ele group(0. 450 0 ±0. 061 4) was obviously declined in comparison to rhbFGF group(P ＜0. 01) . The inhibitory rate of Ele was 24.90 %. In proliferation group, the number of HLE-B3 was increased with the normal cell structure and abundant cytoplasm under the optical microscope. However, in Ele group, the number of HLE-B3 was evidently decreased with less cytoplasm, undistinguished cell structure, condensed and aggregated nucleuses. The result of flow cytometer showed that the percentage of HLE-B3 in G_1 phase in rhbFGF group was 42. 062% ± 1. 270% and that in control group was 46. 422% ±3. 765% with a significant difference(P ＜ 0. 05). HLE-B3 in G_1 phase in Ele group (60. 665% ±2.069%) was evidently increased in comparison with rhbFGF group (P ＜ 0. 01). HLE-B3 in S phase in rhbFGF group compared with control group was increased (51.647% ±1.123% versus 31.842% ± 2. 798%) (P ＜ 0. 01), but that in S phase in Ele group(30. 222% ±3.429%) was lower than rhbFGF group (P ＜ 0. 01). HLE-B3 in G_2 phase in rhbFGF group was decreased in comparison with control group (6. 288% ± 0. 966% versus 21. 735% ± 3. 806%, P ＜ 0. 01), and that in G_2 phase in Ele group (9. 112% ± 1. 659%) compared with proliferation group was increased (P ＜ 0. 01). Conclusion Ele could alter the cell cycle of HLE-B3 and effectively inhibit the HLE-B3 proliferation induced by rhbFGF. Ele may be a reliable and effective drug for prevention and treatment of after cataract.