IGF and Metabolic Endocrinology Group, Department of Clinical Sciences North Bristol, Learning and Research Centre, Southmead Hospital, Bristol, United Kingdom.
Urology. 2011 Aug;78(2):475.e15-21. doi: 10.1016/j.urology.2011.03.031. Epub 2011 Jun 14.
To assess the influence of epigallocatechin-3-gallate (EGCG) on the efficacy of ionizing radiation on prostate cancer cells because of the increased use of dietary interventions, especially by patients with prostate cancer. Radiotherapy is used to treat localized prostate cancer. Some people consume green tea (EGCG) as a chemopreventive agent against prostate cancer. Green tea can act as an antioxidant and induce superoxide dismutase enzymes, which could scavenge the free oxygen radicals generated by radiotherapy.
Prostate cancer cell line DU145 cells were treated with EGCG or radiotherapy, or both. Cell death was assessed using trypan blue cell counting, and apoptosis was confirmed by assessing poly (adenosine phosphate ribose) polymerase cleavage. The antioxidant potential was assessed using Western immunoblotting for manganese superoxide dismutase and copper zinc superoxide dismutase enzymes. Radiotherapy was delivered using a linear accelerator. Cell cycle analysis was performed using flow cytometry.
Radiotherapy at 3.5 Gy induced a 5.9-fold increase in apoptosis of DU145 cells. Subapoptotic doses of EGCG (1.5-7.5 μM) significantly reduced ionizing radiation-induced apoptosis (P < .001), with the inhibitory effect of EGCG on ionizing radiation being most effective when added 30 minutes before radiotherapy (P < .001). In addition, when radiotherapy and EGCG were used together, an approximate 1.5-fold increase in manganese superoxide dismutase levels was seen compared with the control and a 2-fold increase compared with radiotherapy alone.
Radiotherapy is effective in inducing apoptosis in DU145 cells, but its effect was significantly reduced in the presence of EGCG, and this was associated with an increase in the induction of manganese superoxide dismutase.
评估表没食子儿茶素没食子酸酯 (EGCG) 对前列腺癌细胞电离辐射疗效的影响，因为饮食干预的使用越来越多，特别是前列腺癌患者。放射疗法用于治疗局部前列腺癌。有些人将绿茶（EGCG）作为预防前列腺癌的化学预防剂。绿茶可以作为抗氧化剂并诱导超氧化物歧化酶，其可以清除放射治疗产生的游离氧自由基。
用 EGCG 或放射疗法或两者治疗前列腺癌细胞系 DU145 细胞。使用台盼蓝细胞计数评估细胞死亡，通过评估多聚（腺苷二磷酸核糖）聚合酶切割来确认细胞凋亡。使用 Western 免疫印迹法评估抗氧化能力锰超氧化物歧化酶和铜锌超氧化物歧化酶。使用线性加速器进行放射治疗。使用流式细胞术进行细胞周期分析。
3.5 Gy 的放射治疗使 DU145 细胞的凋亡增加了 5.9 倍。亚凋亡剂量的 EGCG（1.5-7.5 μM）显著降低了电离辐射诱导的细胞凋亡（P<0.001），EGCG 对电离辐射的抑制作用在放射治疗前 30 分钟添加时最为有效（P<0.001）。此外，当放射治疗和 EGCG 一起使用时，与对照相比，锰超氧化物歧化酶水平增加了约 1.5 倍，与单独放射治疗相比增加了 2 倍。
放射治疗能有效诱导 DU145 细胞凋亡，但在 EGCG 存在的情况下，其作用显著降低，这与锰超氧化物歧化酶的诱导增加有关。
