Department of Surgery, Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310009, Zhejiang Province, China.
World J Gastroenterol. 2013 Jul 28;19(28):4486-94. doi: 10.3748/wjg.v19.i28.4486.
To investigate the potential roles of Delta-like ligand 4 (DLL4) on the biological behavior of gastric cancer cells and its molecular mechanisms.
A recombinant eukaryotic expression vector containing human DLL4 gene was constructed and transfected into the human gastric cancer cell line SGC7901. Clones with up-regulated DLL4 were selected and amplified. The effect of DLL4 up-regulation on gastric cancer cell growth was assessed using cell growth assay. The migration and invasion were assessed using a transwell migration assay and matrigel invasion assay. Matrix metalloproteinases were detected using the zymogram technique. Cells were implanted subcutaneously into male BALB/c nu/nu mice. Tumor volumes were then calculated and compared. DLL4 staining in the implanted tumor was performed using immunohistochemistry technique.
Growth curves over a six-day time course showed significantly promoted cell proliferation of SGC7901 cells with up-regulated DLL4. DLL4 up-regulation in SGC7901 cells promoted the migration (205.4 ± 15.2 vs 22.3 ± 12.1, P < 0.05) and invasion (68.8 ± 5.3 vs 18.2 ± 6.0, P < 0.05) in vitro and tumorigenicity in vivo (2640.5 ± 923.6 mm(3) vs 1115.1 ± 223.8 mm(3), P < 0.05). Furthermore, significantly increased mRNA level and increased secretion of matrix metalloproteinase-2 (MMP-2) proenzyme were observed in SGC7901 cells with up-regulated DLL4. However, increased MMP-9 mRNA level but decreased extracellular MMP-9 proenzyme level was observed.
Our observations indicated a mechanism by which activation of DLL4-mediated Notch signaling promotes the expression and secretion of MMP-2 proenzyme and influences the progress of gastric cancer.
探讨 Delta 样配体 4（DLL4）在胃癌细胞生物学行为中的潜在作用及其分子机制。
构建了含有人 DLL4 基因的重组真核表达载体，并转染人胃癌细胞系 SGC7901。选择并扩增上调 DLL4 的克隆。通过细胞生长试验评估 DLL4 上调对胃癌细胞生长的影响。通过 Transwell 迁移试验和 Matrigel 侵袭试验评估迁移和侵袭。使用酶谱技术检测基质金属蛋白酶。将细胞皮下植入雄性 BALB/c nu/nu 小鼠。然后计算并比较肿瘤体积。使用免疫组织化学技术检测植入肿瘤中的 DLL4 染色。
六天生长曲线显示，上调 DLL4 的 SGC7901 细胞增殖明显加快。SGC7901 细胞中 DLL4 的上调促进了体外迁移（205.4 ± 15.2 比 22.3 ± 12.1，P < 0.05）和侵袭（68.8 ± 5.3 比 18.2 ± 6.0，P < 0.05），以及体内致瘤性（2640.5 ± 923.6 mm3 比 1115.1 ± 223.8 mm3，P < 0.05）。此外，上调 DLL4 的 SGC7901 细胞中 MMP-2 前酶的 mRNA 水平和分泌量显著增加，而 MMP-9 的 mRNA 水平增加，细胞外 MMP-9 前酶水平降低。
我们的观察结果表明，DLL4 介导的 Notch 信号激活促进了 MMP-2 前酶的表达和分泌，并影响了胃癌的进展。
