电离辐射联合肿瘤坏死因子相关凋亡诱导配体对乳腺癌MCF-7细胞株作用的研究

Effect of Tumor Necrosis factor related apoptosis-inducing Ugand （TRAIL） combined with ionizing radiation on proliferation and apoptosis of breast cancer MCF-7 cell lines

目的 探讨肿瘤坏死因子相关凋亡诱导配体（TRAIL）对人乳腺癌MCF．7细胞株的作用以及与放射治疗联合的可行性。方法1×10^4／ml MCF-7细胞接种至96孔板培养后加入不同浓度的TRAIL、给予不同剂量照射及TRAIL与电离辐射联合，Mrrr法检测细胞抑制率。MCF-7细胞接种至6孔板培养后，分别加入TRAIL（1μg／ml）、给予8Gy照射及TRAIL与8Gy照射联合，流式细胞术检测不同处理组细胞的凋亡率。应用RT-PCR法检测经不同处理后的细胞凋亡相关基因的表达情况。结果TRAIL（1μg／ml）与4、8和12Gy照射联合后对细胞的抑制率明显增加，与单独应用TRAIL及单独照射相比，差异有统计学意义。RT-PCR结果显示Bcl-2、Bcl-Xl基因在TRAIL与8Gy照射联合时表达减弱。结论在体外实验中，乳腺癌MCF-7细胞株对TRAIL不敏感，但TRAIL与电离辐射照射联合后抗肿瘤作用增强，TRAIL可能是一种有临床应用潜能的新型抗肿瘤生物制剂。

Objective To investigate the effect of Tumor necrosis factor related apoptosis-inducing ligand （TRAIL） on breast cancer MCF-7 cell lines and the possibility of TRAIL combined with radiotherapy. Methods 1× 10^4/ml MCF-7 cell suspension were added to each well of 96-well plates, MCF cell were treated with radiotherapy（RT）, TRAIL at different concentration or RT combined with TRAIL. MTT working solution was added and calculated the inhibitory rates of MCF-7 cells. MCF-7 cell suspension was added to 6-well plates then treated with TRAIL（ 1 μg/ml）, 8 Gy RT or TRAIL combined with 8 Gy RT. The rates of apoptosis were detected by flow cytometry after incubated 48 h. RT-PCR methods were employed to analysize the expression of apoptosis related gene in different treatment group. Results MCF-7 cell lines were resistant to TRAIL,but the inhibitory rate was upregulated when MCF-7 cell was treated with TRAIL combined with RT, which had a significant difference compared with RT or TRAIL alone. The expression of Bcl-2 and Bcl-Xl gene were down-regulated when MCF-7 cell lines was treated with 8 Gy RT combined with TRAIL. Conclusions In vitro, MCF-7 cell lines are resistant to TRAIL, but TRAIL combined with radiotherapy increased the cytotoxic effect. TRAIL has a promising prospect in clinical use.