过表达DLL3促进人胃癌细胞的增殖

摘要

目的 构建人全长DLL3的真核表达质粒,并分析上调和下调DLL3对人胃癌细胞增殖的影响.方法 采用PCR扩增人全长DLL3基因并克隆至真核表达载体pCMV-Tag4中,通过酶切及测序鉴定后,瞬时转染HEK293T细胞,并以转染pCMV-Tag4质粒和无转染HEK293T细胞分别为阴性对照和空白对照,实时荧光定量PCR(qRT-PCR)和Western blot鉴定人全长DLL3基因的表达;进一步通过qRT-PCR和Western blot检测人DLL3在人正常口腔上皮细胞GES-1和AGS等3株胃癌细胞中的表达差异;当人DLL3/pCMV-Tag4瞬时转染3株胃癌细胞后,利用MTT检测DLL3过表达后胃癌细胞的增殖;同时,特异性人DLL3 siRNA转染人胃癌细胞MGC803和MKN45,利用MTT检测DLL3下调后胃癌细胞的增殖.结果 成功构建了人全长DLL3/pCMV-Tag4重组质粒,转染HEK293T细胞24 h后,qRT-PCR和Western blot表明DLL3在mRNA和蛋白水平上的表达显著高于对照组;MTT细胞增殖实验显示:过表达DLL3促进胃癌细胞的增殖,下调DLL3后抑制胃癌细胞的增殖.结论 成功构建了人全长DLL3/pCMV-Tag4真核表达质粒并在HEK293T细胞中获得表达,过表达DLL3促进胃癌细胞的增殖,下调DLL3抑制胃癌细胞的增殖,本研究为以DLL3为新靶点对胃癌进行靶向治疗提供新思路.%Objective To construct a eukaryotic expression plasmid carrying human full-length Notch ligand Delta-like 3 (DLL3) gene and study the effect of DLL3 knockdown and overexpression on the proliferation of gastric cancer cells in vitro. Methods Human full-length DLL3 gene was amplified by PCR and cloned into the eukaryotic expression vector pCMV-Tag4. After verification by restriction enzymes and sequencing, the recombinant DLL3/pCMV-Tag4 vector was transiently transfected into HEK293T cells, in which the expressions of human DLL3 mRNA and protein were detected using real-time quantitative PCR and Western blotting, respectively. The expression of DLL3 in normal gastric epithelial cells and gastric cancer cell lines was detected by qRT-PCR and Western blotting. DLL3/pCMV-Tag4 was transfected into 3 gastric cancer cell lines, and their proliferation was assessed with MTT assay. Human gastric cancer cells MGC803 and MKN45 were also transfected with a specific human DLL3-siRNA to assess the effect of DLL3 down-expression on the cell proliferation. Results The recombinant eukaryotic expression vector DLL3/pCMV-Tag4 was successfully constructed and human full-length DLL3 was expressed in HEK293T cells. MTT assay showed that DLL3 over-expression obviously promoted the proliferation and down-regulation of DLL3 inhibited the proliferation of the gastric cancer cells. Conclusion DLL3 overexpression can promote the proliferation of gastric cancer cells in vitro, and down-regulation of DLL3 inhibits the proliferation of gastrc cancer cells,which provides a novel strategy for targeted thrapy of gastric cancer.