Background: Breast cancer is the most common invasive malignancy among women in the world. The current breast cancer therapies pose significant clinical challenges. Low-dose chemotherapy represents a new strategy to treat solid tumors in combination with natural products such as green tea catechins. Epigallocatechin-3-gallate (EGCG) is the major polyphenolic extract from green tea with potent anticancer and antioxidant effects. The purpose of this study was to investigate the effects of EGCG, Arsenic trioxide (ATO) and gamma radiation on MCF-7 cell line. Methods: The anti-proliferative effects of EGCG and ATO individually, moreover in combination with radiation on MCF-7 cells were evaluated with MTT assay. The expression of apoptotic gens (Bax, Bcl-2, Caspase-3 and Fas) was assessed by real-time PCR. Results: Based on the results of MTT assay, EGCG and ATO exhibited dose and time-dependent anti-proliferative effects on MCF-7 cells. The combined therapy of EGCG and ATO in presence and absence radiation could rise cell death up to 80%. Moreover, integrated therapy made Bax up-regulated and Bcl-2 down- regulated. Conclusion: In assessment synergistic effects of integrated therapy with EGCG and ATO and irradiation had been significant impact on low dose chemotherapy for breast cancer treatment.

中文翻译：

---

评估表没食子儿茶素-3-没食子酸酯 (EGCG) 和三氧化二砷的综合治疗与放射治疗对乳腺癌细胞系的协同作用

背景：乳腺癌是世界上女性最常见的侵袭性恶性肿瘤。目前的乳腺癌疗法带来了重大的临床挑战。低剂量化疗代表了一种结合绿茶儿茶素等天然产物治疗实体瘤的新策略。表没食子儿茶素-3-没食子酸酯 (EGCG) 是绿茶中的主要多酚提取物，具有有效的抗癌和抗氧化作用。本研究的目的是研究 EGCG、三氧化二砷 (ATO) 和伽马辐射对 MCF-7 细胞系的影响。方法：采用MTT法评价EGCG和ATO分别与放疗联合对MCF-7细胞的抗增殖作用。通过实时 PCR 评估凋亡基因 (Bax、Bcl-2、Caspase-3 和 Fas) 的表达。结果：根据 MTT 检测结果，EGCG 和 ATO 对 MCF-7 细胞表现出剂量和时间依赖性抗增殖作用。在存在和不存在辐射的情况下，EGCG 和 ATO 的联合治疗可使细胞死亡增加高达 80%。此外，综合治疗使 Bax 上调和 Bcl-2 下调。结论：在评估 EGCG 和 ATO 的综合治疗和放射治疗的协同效应中，对乳腺癌治疗的低剂量化疗产生了显着影响。