Objective: To investigate the effects of down-regulation of expression of neuropilin-2 (NRP-2) by RNA interference (RNAi) technique on proliferation and apoptosis of HCT-8 colon cancer cells. Methods: NRP2-siRNA and negative control (NControl)-siRNA were transferred into HCT-8 colon cancer cells by liposomes (lip2000) as transfection group and negative control group, and phosphate buffered solution (PBS) was added as blank control group. Quantitative reverse transcription PCR (RT-qPCR) and Western blot were used to detect the transfection effect. The proliferation of cells in the three groups was examined by cell counting kit (CCK) assay, colony-forming unit assay and Ki-67 protein staining assay, respectively. Moreover, the apoptosis of cells in the three groups was determined by acridine orange/propranidine iodide (AO/PI) staining method. Results: The results of RT-qPCR and Western blot showed that the relative expression of NRP-2 mRNA and the content of NRP-2 protein in the transfer group decreased (0.46±0.05 vs 0.99±0.05 and 1.00±0.06; 1.04±0.06 vs 1.73±0.09 and 1.65±0.11) (all P<0.05). The results of CCK-8 demonstrated that the optical density of transfection group was significantly lower than that of the negative control group and the blank control group(24 h: 0.53±0.04 vs 0.82±0.07 and 0.87±0.07; 48 h: 0.54±0.05 vs 1.00±0.09 and 1.17±0.05; 72 h: 0.75±0.05 vs 1.31±0.13 and 1.50±0.03; 96 h:1.05±0.04 vs 1.46±0.09 and 1.86±0.06) (all P<0.05). The results of colony-forming unit assay indicated that the proliferation ability of the cells in the transfer group was significantly lower than that in the other two groups (134.67±8.74 vs 245.33±19.14 and 300.33±14.01, P<0.05). The results of Ki-67 protein staining assay showed that compared with the negative control group and blank control group, the expression of Ki-67 protein was significantly decreased in the transfection group (5.93±0.22 vs 8.36±0.09 and 8.70±0.21, P<0.05). The results of AO/PI assay revealed that the ratio of apoptotic cells to living cells in the transfer group was significantly higher than that in the other two groups (0.43±0.07 vs 0.14±0.04 and 0.11±0.04, P<0.05). Conclusion: The proliferation ability of HCT-8 colon cancer cells decreases, and the apoptosis ability increases by decreasing the expression of NRP-2.
目的： 探讨应用RNAi技术降低神经纤毛蛋白-2（NRP-2）表达后对结肠癌细胞HCT-8增殖和凋亡的影响。 方法： 通过脂质体lip2000分别将NRP2-siRNA和NControl-siRNA转染入HCT-8中作为转染组和阴性对照组，加入磷酸盐缓冲液作为空白对照组，通过实时荧光定量PCR（RT-qPCR）和Western印迹法验证转染效果，采用细胞计数试剂盒（CCK）法、平板克隆实验和Ki-67蛋白染色实验检测3组细胞的增殖情况，吖啶橙/碘化丙啶（AO/PI）荧光染色实验检测3组细胞的凋亡情况。 结果： RT-qPCR和Western印迹法结果表明转染组细胞NRP-2 mRNA相对表达量和NRP-2蛋白含量降低（0.46±0.05比0.99±0.05和1.00±0.06，1.04±0.06比1.73±0.09和1.65±0.11）（均P<0.05），CCK法表明，转染组各时段的增殖能力较阴性对照组和空白对照组显著降低（24 h为0.53±0.04比0.82±0.07和0.87±0.07，48 h为0.54±0.05比1.00±0.09和1.17±0.05，72 h为0.75±0.05比1.31±0.13和1.50±0.03，96 h为1.05±0.04比1.46±0.09和1.86±0.06）（均P<0.05）；平板克隆实验显示转染组细胞较其他两组克隆形成能力显著下降（134.67±8.74比245.33±19.14和300.33±14.01，P<0.05）；Ki-67蛋白检测显示与对照组相比，转染组的细胞Ki-67含量显著下降（5.93±0.22比8.36±0.09和8.70±0.21，P<0.05）；AO/PI实验显示转染组较对照组相比凋亡细胞/活细胞比例显著上升（0.43±0.07比0.14±0.04和0.11±0.04，P<0.05）。 结论： 降低NRP-2表达可使结肠癌细胞HCT-8的增殖能力下降，凋亡能力上升。.
Keywords: Cell apoptosis; Cell proliferation; Colonic Neoplasms; Neuropilin-2.