RESUMO
@#[摘 要] 目的：探讨miR-125a-5p通过调控Bcl-2相关永生基因4（Bcl-2-associated athanogene 4，BAG4）的表达抑制胃癌细胞迁移和侵袭的分子机制。方法：选用2014年1月至2015年12月兰州大学第一医院手术切除的82例胃癌组织标本及配对的癌旁组织以及人胃癌细胞系MGC803、BGC823、SGC7901、HGC27及人胃黏膜上皮细胞（GES-1），qPCR法检测胃癌组织、癌旁组织及胃癌细胞系中miR-125a-5p的表达水平。分别将miR-125a-5p mimic、miR-125a-5p inhibitor、（si-BAG4）siRNA-BAG4及阴性对照质粒转染至胃癌细胞，划痕愈合实验和Transwell侵袭实验分别检测miR-125a-5p/BAG4信号轴对胃癌细胞迁移和侵袭能力的影响。WB检测胃癌细胞中BAG4蛋白的表达。荧光素酶报告基因实验验证miR-125a-5p和BAG4之间的靶向调控关系。结果：miR-125a-5p在胃癌组织和细胞系中均低表达（均P<0.01）。miR-125a-5p的表达与患者的性别（P=0.953）、年龄（P=0.772）、肿瘤部位(P=0.867)、组织学分级（P=0.745）和肿瘤大小（P=0.088）无相关性，与胃癌患者的T分期（P=0.003）、N分期（P=0.001）、M分期（P=0.027）和TNM分期（P=0.035）显著相关，差异有统计学意义。miR-125a-5p低表达是胃癌患者总生存时间的独立危险因素。过表达miR-125a-5p显著抑制胃癌细胞的迁移和侵袭能力（均P<0.01）。敲降BAG4可逆转miR-125a-5p inhibitor对胃癌细胞迁移和侵袭能力的抑制作用。荧光素酶报告基因实验证实miR-125a-5p可与BAG4 3'非翻译区（untranslated regions，UTR）结合抑制其表达。结论：miR-125a-5p通过靶向下调BAG4的表达水平进而抑制胃癌细胞的迁移和侵袭。
RESUMO
Nursery nitrogen application has been used to improve seedling quality. The technique has received little attention with bare-root seedlings and their subsequent field performance on weed competition sites. Our research objective was to examine responses of one- and two- year-old bare-root Olga Bay larch (Larix olgensis Henry) seedlings to nursery nitrogen supplements and subsequent one-year field performance on a competitive site. The fertilizer levels (kg N ha-1) were 0 (control), 60 (conventional fertilization, 60 C), 120 (additional nitrogen applied two times, 120 L), 180 (additional nitrogen applied three times, 180 L) and N were applied in increments of 30 kg ha-1 at 15-day interval to maintain a base nutrient level. Although pre-planting morphological attributes and nitrogen status of one-year-old (1a) seedlings were more sensitive to 60 C than for two-year-old (2a) seedlings, the conventional application failed to enhance their field survival(15.6% vs 17.8%), relative height growth (89.0% vs 79.6%), and relative diameter growth (17.0% vs 22.9%). The 1a seedlings‘ field survival (15.6% for 0, 17.8% for 60 C) and 2a seedlings‘ relative height growth rate (11.0% for 0, 8.9% for 60 C) were not increased significantly until they were provided the 120 L (survival of 23.3% for 1a, relative height growth rate of 15.0% for 2a). According to pre-planting attributes and field performance, optimum nursery nitrogen application was 120 L for the 2a seedlings and 180 L for 1a seedlings. Except for component nitrogen concentration, pre-planting morphological attributes and component N content for the 2a seedlings were as much 3.3 to 37.7 times that of 1a seedlings. In conclusion, the contrasting survival of poor (15.6%-28.9%) for 1a seedlings and high (84.4%-91.1%) for 2a seedlings indicated that additional nitrogen fertilizer would not equal the benefits of an another year‘s growth in the nursery. Successful reforestation could not be fulfilled by 1a seedlings regardless of their pre-nutrients. An alternative technique for sites with competing vegetation was to apply 120kg N ha-1 in the nursery during July and August on 2a seedlings.