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Objective:To investigate the effect of pterostilbene on the growth, apoptosis and autophagy of a human papillomavirus type 16 (HPV-16) -immortalized cervical epithelial cell line H8.Methods:H8 cells were treated with pterostilbene at different concentrations of 0 (control group) , 25, 50, 75, 100 μmol/L for 24 and 48 hours. Cell counting kit-8 (CCK8) assay was performed to evaluate the cellular proliferative activity, flow cytometry was conducted to detect apoptosis and cell cycle, monodansylcadaverine (MDC) staining and fluorescence microscopy were performed to detect autophagy, and Western blot analysis was conducted to determine the expression of the cell cycle-related protein cyclinD1, apoptosis-related proteins caspase-3 and caspase-9, autophagy-related proteins Beclin1, microtubule-associated protein 1 light chain 3 (LC3) -Ⅱ/Ⅰ, ATG5 and P62, as well as HPV oncoproteins E6 and E7. Statistical analysis was carried out by using one-way analysis of variance, repeated measures analysis of variance and least significant difference- t test. Results:After 48-hour treatment with pterostilbene at different concentrations of 0, 25, 50, 75, 100 μmol/L, the relative cellular proliferation rate significantly differed among the groups (100.00% ± 1.56%, 99.02% ± 4.97%, 93.59% ± 2.01%, 81.28% ± 4.90%, 69.17% ± 7.56%, respectively; F = 77.22, P < 0.05) , and gradually decreased along with the increase in the concentration of pterostilbene; compared with the control group, the pterostilbene groups all showed significantly decreased cellular proliferation rate (all P < 0.05) . After 24-hour treatment with pterostilbene, the proportions of H8 cells at G1, G2 and S phases significantly differed among the above groups ( F = 7 845.00, 51.14, 266.50, respectively, all P < 0.05) ; compared with the control group, the pterostilbene groups showed significantly increased proportions of H8 cells at G1 and G2 phases (all P < 0.05) , but significantly decreased proportions of H8 cells at S phase ( P < 0.05) . After 48-hour treatment with pterostilbene, the apoptosis rate was significantly higher in the 25-, 50-, 75- and 100-μmol/L pterostilbene groups (14.66% ± 0.22%, 13.50% ± 0.49%, 14.56% ± 0.19%, 15.30% ± 0.76%, respectively) than in the control group (11.58% ± 0.50%, all P < 0.05) . After 24-hour treatment with pterostilbene, MDC staining showed only a small number of H8 cells with bright dot-like fluorescence in the control group, but increased number of autophagosome-positive H8 cells with bright dot-like fluorescence in the pterostilbene groups. Western blot analysis revealed that there were significant differences in the protein expression of cyclin D1, caspase-3, caspase-9, Beclin1, LC3-Ⅱ/Ⅰ, ATG5, P62, E6 and E7 among the control and pterostilbene groups after 24- and 48-hour treatment with pterostilbene (all P < 0.05) . The treatment with pterostilbene could down-regulate the expression of cyclin D1, E6 and E7, and up-regulate the expression of caspase-3, caspase-9, Beclin1, LC3-Ⅱ/Ⅰ, ATG5 and P62, with significant differences between the control group and most pterostilbene groups in expression of the above proteins (all P < 0.05) . Conclusion:Pterostilbene can inhibit the proliferation of H8 cells, promote their apoptosis and autophagy, and down-regulate the expression of oncogenes E6 and E7.
RÉSUMÉ
Objective To explore the effect of tea polyphenols on the growth of human papillomavirus 16 (HPV16) subgenes-immortalized human cervical epithelial cells (H8 cells).Methods Cultured H8 cells were divided into 5 groups to be treated with 0 (control group),6.25,12.5,25 and 50 mg/L tea polyphenols respectively for 24,36,and 48 hours,and then cell counting kit-8 (CCK8)assay was performed to detect cell proliferation.After 24 hours of incubation,flow cytometry was conducted to detect cell apoptosis and cell cycle,and fluorescence microscopy to observe the morphology of apoptotic cells.Results After incubation with tea polyphenols at different concentrations for 24,36 and 48 hours,the proliferation of H8 cells was inhibited,and 12.5 mg/L tea polyphenols could inhibit the relative growth rate of H8 cells in a time-dependent manner.Flow cytometry showed that there was a significant difference in cell apoptosis rate among the 6.25-,12.5-,25-,50-mg/L tea polyphenols groups and the control group (52.62％ ± 0.62％,52.22％ ± 0.72％,42.52％ ± 0.90％,45.96％ ± 2.11％,29.96％ ± 0.70％ respectively,F =272.0,P ＜ 0.05).Moreover,all the tea polyphenol groups showed significantly increased cell apoptosis rate compared with the control group (all P ＜ 0.05).Fluorescence microscopy showed karyopyknosis,nuclear fragmentation and other typical apoptotic morphological changes in H8 cells in tea polyphenols groups.There were significant differences in the percentage of cells in G1,G2 phase and cell proliferation index among the 5 groups (all P ＜ 0.05).Compared with the control group,the 6.25-,12.5-,25-mg/L tea polyphenols groups showed significantly increased percentage of cells in G1 phase (55.96％ ± 0.72％,54.12％ ± 3.20％,65.30％ ± 1.51％ respectively,all P ＜ 0.05),but significantly decreased percentage of cells in G2 phase (3.17 ± 1.82％,4.94 ± 1.46％,4.65 ± 4.26％ respectively,all P ＜ 0.05) and lower cell proliferation index(0.44 ± 0.01,0.46 ± 0.02,0.36 ± 0.01 respectively,all P ＜ 0.05).Conclusion Tea polyphenols can inhibit the proliferation of H8 cells,induce cell apoptosis,and block cell cycle progression.
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Objective To investigate the protective effect of lycium barbarum polysaccharide (LBP) on DNA damage of HSF cells induced by UV.Methods We established the model of UV induced photo damage in HSF cells.We detected the viability of HSF cells by using MTT colorimetry.The UV absorption spectrum of LBP was also measured by UV spectrophotometer.The level of ROS was detected by DCFH-DA fluorescent probe method.Comet assay was employed to evaluate the DNA strand breakage damage.Results When the concentration of LBP was less than or equal to 300μg/ml,there was no significant effect on the proliferation of HSF cells (P＞0.05).When the concentration was more than 300 μg/ml,it could inhibit the cell proliferative activities (P＜0.05).Compared to the UV groups,UV+LBP groups can respectively improve the cell proliferation activity (P＜0.05).The absorbance was slight range 280 from 400 nm.Compared with the UV group,the relative fluorescence intensity and the migration distance of UV+ LBP groups were significantly decreased (P＜0.05).Conclusions Lycium barbarum polysaccharide can effectively inhibit the proliferation activity and protect the breakage of DNA strand induced by UV,which is probably due to its action of removing free radicals.
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Objective To evaluate the scavenging effect of crude polysaccharides extracted from Lycium barbarum (LBP) on reactive oxygen species in ultraviolet radiation-induced HaCaT cells,and to explore its possible mechanism.Methods Cultured immortalized human keratiuocyte HaCaT cells were divided into 6 groups:blank control group receiving no treatment,LBP group treated with crude LBP alone,ultraviolet A (UVA) group treated with UVA radiation alone,ultraviolet B (UVB) group treated with UVB radiation alone,UVA + LBP group treated with crude LBP for 24 hours followed by UVA radiation,and UVB + LBP group treated with crude LBP for 24 hours followed by UVB radiation.MTT colorimetry was performed to evaluate the cellular proliferative activity,UV spectrophotometric method to measure the UVA and UVB absorption of crude LBP,dichlorodihydrofluorescein diacetate (DCFH-DA) fluorescent probe assay to detect the level of ROS,enzymatic-biochemical method to estimate the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px),as well as to detect the leakage of lactate dehydrogenase (LDH).Results Crude LBP at different concentrations of 0,100,200,300,400,500,600,1 500,2 000 mg/L had no obvious effects on the proliferative activity of HaCaT cells.Crude LBP had a high transmittance of ultraviolet rays at 280-400 nm.Compared with the blank control group,the UVA group and UVB group both showed significantly higher LDH leakage and ROS level,lower activities of SOD and GSH-Px (P ＜ 0.001 or 0.05).Pretreatment with crude LBP before the ultraviolet radiation could significantly increase the activities of SOD and GSH-Px,decrease the LDH leakage and ROS level in the UVA + LBP group and UVB + LBP group compared with the UVA group or UVB group (P ＜ 0.05).Conclusion Crude LBP have no effect of sunscreening agents,but can effectively scavenge ROS,decrease LDH leakage,inhibit ultraviolet radiation-induced photodamage in HaCaT cells,which may be associated with the enhancement of antioxidant enzyme activity.