亚硒酸钠诱导人急性早幼粒细胞白血病细胞株NB4细胞氧化应激和细胞凋亡

目的研究亚硒酸钠诱导NB4细胞的氧化应激和细胞凋亡。方法MTT比色法检测亚硒酸钠对NB4细胞的生长抑制;用形态学、DNA琼脂糖电泳和流式细胞术研究亚硒酸钠诱导NB4细胞凋亡的作用;用化学发光法和比色法研究亚硒酸钠对NB4细胞内氧化应激的影响。 结果亚硒酸钠可以时间和剂量依赖性地抑制NB4细胞生长和诱导NB4细胞凋亡。亚硒酸钠(≥5 μmol·L^-1)提高了NB4细胞内ROS水平,同时伴有细胞内还原型谷胱甘肽含量下降,而抗氧化剂NAC可抑制亚硒酸钠诱导的NB4细胞氧化应激和细胞凋亡。结论亚硒酸钠诱导NB4细胞氧化应激可能是其诱导NB4细胞凋亡的重要机理。

SODIUM SELENITE-INDUCED OXIDATIVE STRESS AND APOPTOSIS IN HUMAN ACUTE PROMYELOCYTIC LEUKEMIA NB4 CELLS

AIM: To explore sodium selenite-induced oxidative stress and apoptosis in human promyelocytic leukemia NB4 cells. METHODS: The growth inhibition of NB4 cells was measured by MTT test. Apoptosis was determined morphologically by Giemsa stain and by DNA ladder formation in electrophoresis. Quantitation of apoptosis was determined by percentage of PI stained cells containing subdiploid amount of DNA measured by flow cytometry. Generation of reactive oxidative species (ROS) in NB4 cells was determined by lucigenin dependent chemoluminescent (CL) test. Spectrophotometer was used to measure the level of reduced glutathione, superoxide dismutase (SOD) and glutathione peroxidase in the cell. RESULTS: Sodium selenite was shown to inhibit the growth of NB4 cells. Sodium selenite induced apoptosis with dose and time dependency: the ratio of subdiploid cells in control group was 1.3% +/- 0.7%. The 5 mumol.L-1 group was 10.4% +/- 1.4%, 10 mumol.L-1 group was 16% +/- 1%, and the 20 mumol.L-1 group was 27.3% +/- 0.8%. Sodium selenite (> or = 5 mumol.L-1) enhanced the ROS level markedly in NB4 cells (in 20 mumol.L-1 group ROS level was increased by 17 times, compared with control group), accompanied with decrease of reduced intracellular glutathione. These effects were time and dose dependent. N-acytlcysteine as an antioxidant was found to inhibit sodium selenite-induced oxidative stress and apoptosis in NB4 cells. CONCLUSION: Sodium selenite can induce apoptosis of NB4 cells and would possibly be used as an agent for the treatment of malignancy. The main mechanism of action might be related to oxidative stress induced by sodium selenite, thereby, leading to apoptosis as shown in NB4 cells.