Liang Xiao-Qiu, Cao En-Hua, Zhang Yan, Qin Jing-Fen
Institute of Biophysics, Academia Sinica, 15 Datun Road, Chaoyang District, Beijing 100101, China.
FEBS Lett. 2004 Jul 2;569(1-3):94-8. doi: 10.1016/j.febslet.2004.05.057.
The tumor suppressor p53 regulates the expression of various genes that promote apoptosis. PIG11 (P53-induced gene 11), also referred to as TP53I11 (tumor protein p53 inducible protein 11), is a direct p53 target gene. Recent data demonstrated that PIG11 was up-regulated markedly in arsenic trioxide induced apoptosis by DDRT-PCR, suggesting a new class of p53 target genes that sensitize cells to the effects of chemotherapeutic agents. In this study, through the construction of a recombinant GFP-PIG11 expression vector and transfection of HEK293 cells with GFP or GFP-PIG11, the role of PIG11 in apoptosis was analyzed. Results demonstrated that the percentage (11.38%) of apoptotic cells with GFP-PIG11 transfection was higher than that (7.28%) of with only GFP transfection (P<0.05). At 24 h after 1 microM of arsenic trioxide treatment, apoptotic cells exhibited a significant increase in the expression of GFP-PIG11 (36.67%+/-2.78), in contrast, 10.50%+/-2.03 only GFP and 5.25%+/-0.96 vehicle control (P<0.01). In addition, we showed that intracellular content of reactive oxygen species (ROS) was 9.66+/-0.52 in GFP-PIG11 transfection, higher than 5.21+/-0.08 in GFP only and 5.99+/-0.45 in vehicle control (P<0.01). The above results suggest that overexpression of PIG11 could induce cell apoptosis in the low levels and enhanced the apoptotic effects of arsenic trioxide. The process could be involved in intracellular generation of ROS.
肿瘤抑制因子p53可调节多种促进细胞凋亡的基因的表达。PIG11（p53诱导基因11），也被称为TP53I11（肿瘤蛋白p53诱导蛋白11），是p53的一个直接靶基因。近期数据表明，通过DDRT-PCR技术发现在三氧化二砷诱导的细胞凋亡中PIG11显著上调，提示这是一类新的使细胞对化疗药物作用敏感的p53靶基因。在本研究中，通过构建重组GFP-PIG11表达载体并将GFP或GFP-PIG11转染至HEK293细胞，分析了PIG11在细胞凋亡中的作用。结果显示，转染GFP-PIG11的凋亡细胞百分比（11.38%）高于仅转染GFP的细胞（7.28%）（P<0.05）。在1 microM三氧化二砷处理24小时后，凋亡细胞中GFP-PIG11的表达显著增加（36.67%±2.78），相比之下，仅转染GFP的细胞为10.50%±2.03，空白对照组为5.25%±0.96（P<0.01）。此外，我们发现转染GFP-PIG11的细胞内活性氧（ROS）含量为9.66±0.52，高于仅转染GFP的细胞（5.21±0.08）和空白对照组（5.99±0.45）（P<0.01）。上述结果表明，PIG11的过表达可在低水平诱导细胞凋亡，并增强三氧化二砷的凋亡作用。该过程可能与细胞内ROS的产生有关。
