Ghandadi Morteza, Behravan Javad, Abnous Khalil, Mosaffa Fatemeh
Biotechnology Research Center, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.
Oncol Res Treat. 2016;39(1-2):54-9. doi: 10.1159/000442144. Epub 2015 Dec 21.
Reactive oxygen species (ROS) are not only harmful by-products of the cellular metabolism but also essential components of cell signaling, contributing to various physiologic features including cytokine and growth factor signaling. Here, we examined the role of ROS in the cytotoxic effects of tumor necrosis factor-x237A; (TNF-x237A;) in MCF-7 cells and their drug-resistant counterparts, MCF-7/MX cells.
ROS levels were evaluated following TNF-x237A; exposure using 2',7'-dichlorodihydrofluorescein diacetate (H2DCF-DA) as fluorescent probe, and the TNF-x237A; cytotoxic effects were examined using the dimethylthiazolyl-2,5-diphenyl tetrazolium bromide (MTT) assay.
TNF-x237A; led to ROS accumulation only in MCF-7/MX and not in MCF-7 cells. The role of ROS in the cytotoxic effects of TNF-x237A; was further evaluated by inhibition of ROS accumulation in MCF-7/MX cells and by induction of ROS generation in MCF-7 cells along with TNF-x237A; treatment. ROS accumulation sensitized the MCF-7 cells to the cytotoxic effects of TNF-x237A; while inhibition of ROS accumulation attenuated the cytotoxic effects of TNF-x237A; in MCF-7/MX cells. Following TNF-x237A; treatment, the activities of antioxidant enzymes (superoxide dismutase, glutathione peroxidase, glutathione reductase, and catalase) were evaluated in both cell lines. The results of the enzyme assays revealed that superoxide dismutase activity was enhanced in MCF-7 but not in MCF-7/MX cells.
ROS accumulation in MCF-7/MX cells may be involved in the higher cytotoxic effects of TNF-x237A; in the MCF-7/MX cell line.
活性氧（ROS）不仅是细胞代谢的有害副产物，也是细胞信号传导的重要组成部分，参与包括细胞因子和生长因子信号传导在内的各种生理功能。在此，我们研究了ROS在肿瘤坏死因子-x237A（TNF-x237A）对MCF-7细胞及其耐药对应物MCF-7/MX细胞的细胞毒性作用中的作用。
使用2',7'-二氯二氢荧光素二乙酸酯（H2DCF-DA）作为荧光探针，在TNF-x237A暴露后评估ROS水平，并使用噻唑蓝（MTT）法检测TNF-x237A的细胞毒性作用。
TNF-x237A仅导致MCF-7/MX细胞中ROS积累，而未导致MCF-7细胞中ROS积累。通过抑制MCF-7/MX细胞中的ROS积累以及在MCF-7细胞中与TNF-x237A处理一起诱导ROS生成，进一步评估了ROS在TNF-x237A细胞毒性作用中的作用。ROS积累使MCF-7细胞对TNF-x237A的细胞毒性作用敏感，而抑制ROS积累减弱了TNF-x237A在MCF-7/MX细胞中的细胞毒性作用。在TNF-x237A处理后，评估了两种细胞系中抗氧化酶（超氧化物歧化酶、谷胱甘肽过氧化物酶、谷胱甘肽还原酶和过氧化氢酶）的活性。酶活性测定结果显示，MCF-7细胞中超氧化物歧化酶活性增强，而MCF-7/MX细胞中未增强。
MCF-7/MX细胞中的ROS积累可能与TNF-x237A在MCF-7/MX细胞系中更高的细胞毒性作用有关。
