The Effect Of Tea Polyphenols On Proliferation And Apoptosis In Human Cervical Carcinoma HeLa Cells And Its Possible Mechanism

Objectives:To investigate the effect of Tea Polyphenols(TPs) on the proliferation and apoptosis in human cervical carcinoma HeLa cells and possible mechanisms.Methods:The effect of TPs on the proliferation of cervical carcinoma Hela cells was tested by MTT assay; cells was divided into different groups according to the time and concentration of TPs;the effect of TPs on the growth of cervical carcinoma Hela cells was tested by colony formation experiment.The morphological changes of apoptosis were observed with light and fluore-scance microscope respectively. Flow cytometry assay was adopted to detect the effect of TPs on cell cycle and apoptosis rate.The mitochondrial membrane potential (ΔΨm) was measured by Rh123 staining. Western Blot was adopted to analyze the expression of proteins related to apoptosis-mitochondrial signal transduction pathway, such as Bcl-2. Colorimetric assay was used to detect the activities of caspase-9 and caspase-3.Results:TPs inhibited the growth of cervical carcinoma Hela cells, the inhibition rate elevated with increasing of the concentration of TPs and time of administration in MTT test; it displayed strong proliferation inhibitory effect in a dose-and-time-dependent manner. Colony formation experiment showed that TPs could inhibit the colony formation of HeLa cells, its inhibitory effect augmented with increasing in TPs'concentration.After treated with TPs for 48h, there were obviously morphologic changes in HeLa cells. We found morphologic changes with regard to nuclear fragmentation and apoptotic body by fluorescence microscope. TPs could increase the cell number in S phase and decrease the number in G0/G1 phase, the cell growth was arrested in S phase; TPs could induce Hela cells apoptosis with dose-dependent.The mitochondrial membrane potential of HeLa cells was decreased. The fluorescence potent of Rh123 in TPs groups was much higher than that in control group, and the difference was significant (P<0.01). TPs could decrease the expression of Bcl-2 protein in a dose-dependent manner by Western blot. TPs fostered the activities of caspase-9 and caspase-3 in a dose-dependent manner, tested by caspase-9 and caspase-3 Colorimetric Assay Kit. After being treated with 25μg/ml,50μg/ml, 100μg/ml,200μg/ml TPs for 48h, the OD value of caspase-9 was 0.281±0.002, 0.493±0.003,0.547±0.006,0.745±0.004 respectively, the difference was significant in TPs groups compared with control group (0.238±0.002, P<0.01); After being treated with 25μg/ml,50μ/ml, 100μg/ml,200μg/ml TPs for 48h, the OD value of caspase-3 in TPs group was higher than that in control group (P<0.05).Conclusion:1. TPs have strong inhibitory effect on proliferation of HeLa cells in a dose-and-time-dependent manner.2. TPs induced HeLa cells arrest in S phase. TPs induced the apoptosis of HeLa cells in dose-dependent manner.3. The effect of TPs on apoptosis of HeLa cells may be related to the pathway of mitochondrosome, that Bcl-2, caspase-9 and caspase-3 may be the regulating-target of TPs.