microRNA-486对结直肠癌裸鼠皮下移植瘤生长抑制作用及其机制的研究

摘要

Background and purpose:This study was to investigate the effect of miRNA-486 on the growth of human colorectal cancer cell line SW620 xenograft in nude mice and to explore the possible mechanism of action. Methods:Eighteen mice were randomly divided into three groups, including the experimental group, the negative control group and the blank control group. Each group contained 6 mice. The SW620 cell line was inoculated subcutaneously into nude mice to establish the model of human colorectal cancer xenografts. Peritumoral injection of miRNA-486 overexpres-sion plasmid, or blank vector and PBS were performed every 3 days. The volumes of subcutaneous tumors in each group of inoculated mice were compared. Then mice were sacrificed 3 weeks after infection. Immunohistochemistry and Western blot were used to measure the expression of neuropilin-2 (NRP2).Results:The growth rate of tumors in the experimental group was significantly lower than that in the negative control group and the blank control group. After 21 days, the size of transplanted tumors in the experimental group nude mice was (0.32±0.12) cm3, that in the negative control group was (0.77±0.31) cm3, and that in blank control group was (0.82±0.18) cm3. Tumor mass in the experimental group was sig-nificantly smaller than that in the other two groups (P=0.006<0.05). Tumor mass in the experimental group was (0.40±0.08) g, significantly smaller than that in the negative control group (0.75±0.18) g and in the blank control group (0.79±0.18) g (P=0.008<0.05). Compared with the expression of NRP2 in other groups, the growth of tumor in the experimental group de-clined (P=0.000<0.05).Conclusion:Colorectal cancer cell line SW620 xenografted tumor in nude mice can be suppressed after injection of miR-486, which may decrease the expression of NRP2.%背景与目的：越来越多的证据表明microRNA在生物进程的各个阶段发挥重要作用。在不同的恶性肿瘤中microRNA-486表达上调或者下调，但microRNA-486对人结直肠癌潜在的作用尚不清楚。该研究旨在探讨其对细胞系SW620裸鼠皮下移植瘤生长情况的影响及其可能的作用机制。方法：取18只裸鼠，按简单随机法分为实验组、阴性对照组和空白对照组。每组5只，分别皮下接种SW620细胞。造模成功后实验组、阴性对照组、空白对照组每3天分别于瘤周注射miRNA-486过表达质粒、空白载体及等量PBS，比较各组裸鼠皮下瘤体的体积，接种3周后处死裸鼠，取出皮下瘤组织，用免疫组织化学法和Western blot法分析比较neuropilin-2的表达。结果：实验组瘤体生长速度明显低于阴性对照组和空白对照组；实验组裸鼠皮下种植瘤的大小为(0.32±0.12) cm3，阴性对照组为(0.77±0.31) cm3，空白对照组为(0.82±0.18) cm3；实验组瘤体体积显著小于其他两组体积(P=0.006)；实验组瘤体质量为(0.40±0.08) g，明显低于阴性对照组(0.75±0.18) g及空白对照组(0.79±0.18) g(P=0.008)；实验组种植瘤中neuropilin-2的表达量较另外两组下降(P=0.000)。结论：注射miR-486过表达质粒后结直肠癌细胞SW620裸鼠皮下移植瘤的生长可受到抑制，其作用可能是通过降低neuropilin-2的表达来实现的。miR-486有望成为结直肠癌治疗新的靶点。