Cui Xiao-Peng, Wang You, Lu Mu-Dan, Li Peng, Shen Ai-Guo
Department of General Surgery, Affiliated Hospital, Nantong University, Nantong, Jiangsu, 226001, PR China.
Ai Zheng. 2007 Dec;26(12):1304-8.
BACKGROUND & OBJECTIVE: Arsenic trioxide (As(2)O(3)) is a new drug used to treat solid tumors. However, the mechanism is still unclear. This study was to investigate the effects of As(2)O(3) on the proliferation of human hepatocellular carcinoma (HCC) cell line SMMC-7721, and to explore the mechanisms.
When treated with 0-8 micromol/L As(2)O(3) for 96 h, the survival rate of SMMC-7721 cells was determined by WST-8 assay. When treated with 2 micromol/L As(2)O(3) for 72 h, the expression of P27(kip1) and c-Jun activation domain-binding protein 1 (JAB1) in SMMC-7721 cells were detected at different time points by Western blot, the subcellular localization of P27(kip1) and JAB1 was detected by subcellular fractionation and immunofluorescent staining.
As(2)O(3) significantly inhibited the proliferation of SMMC-7721 cells. The 50% inhibition concentration (IC50) of As(2)O(3) to SMMC-7721 cells was (1.81+/-0.41) micromol/L at 96 h. When SMMC-7721 cells were treated with 2 mumol/L As(2)O(3) for 12 h, the expression of JAB1 was down-regulated and that of P27kip1 was up-regulated. Furthermore, P27(kip1) and JAB1 proteins were translocated from the cytoplasm into nuclei when cells were exposed to 2 micromol/L As(2)O(3) for 12 h and 24 h, respectively. The nuclear accumulation of both proteins was also observed under fluorescence microscope after treatment of 2 micromol/L As(2)O(3).
As(2)O(3) attenuates JAB1 expression, thereby disturbs the location and expression of P27(kip1), and may participate in regulating the proliferation of SMMC-7721 cells through interfering with the function of P27(kip1).
三氧化二砷（As₂O₃）是一种用于治疗实体瘤的新药。然而，其作用机制仍不清楚。本研究旨在探讨As₂O₃对人肝癌细胞系SMMC - 7721增殖的影响，并探索其作用机制。
用0 - 8 μmol/L As₂O₃处理SMMC - 7721细胞96小时后，采用WST - 8法检测细胞存活率。用2 μmol/L As₂O₃处理SMMC - 7721细胞72小时后，在不同时间点通过蛋白质免疫印迹法检测P27（kip1）和c - Jun激活域结合蛋白1（JAB1）的表达，通过亚细胞分级分离和免疫荧光染色检测P27（kip1）和JAB1的亚细胞定位。
As₂O₃显著抑制SMMC - 7721细胞的增殖。96小时时，As₂O₃对SMMC - 7721细胞的半数抑制浓度（IC50）为（1.81±0.41）μmol/L。当用2 μmol/L As₂O₃处理SMMC - 7721细胞12小时时，JAB1的表达下调，P27kip1的表达上调。此外，当细胞分别用2 μmol/L As₂O₃处理12小时和24小时后，P27（kip1）和JAB1蛋白分别从细胞质转位至细胞核。用2 μmol/L As₂O₃处理后，在荧光显微镜下也观察到这两种蛋白的核内聚集。
As₂O₃减弱JAB1的表达，从而扰乱P27（kip1）的定位和表达，并可能通过干扰P27（kip1）的功能参与调节SMMC - 7721细胞的增殖。
