Edg4基因小分子干扰RNA载体的构建及其对卵巢上皮性癌细胞的沉默效应

目的构建针对Edg4基因的小分子干扰RNA（siRNA）载体,初步观察其对卵巢上皮性癌（卵巢癌）细胞的沉默效应。方法利用软件分析、设计针对人Edg4 mRNA的siRNA靶序列,合成发夹样DNA序列;退火成双链,克隆至真核表达载体pRNAT—U6．1质粒上,经PCR技术鉴定及DNA双向测序证实其序列无误后,用脂质体包裹并转染卵巢癌细胞系SKOV3细胞,用荧光显微镜初步观察其在SKOV3细胞中的转染率。采用实时荧光定量荧光定量PCR技术检测转染前后SKOV3细胞中Edg4 mRNA的表达,生化法测定转染前后SKOV3细胞上清液中溶血磷脂酸（LPA）含量的变化,流式细胞术检测转染后SKOV3细胞的凋亡率。结果经PCR技术鉴定及DNA双向测序证实重组真核表达载体的序列无误,并将此命名为pRNAT—U6．1—siEdg4。荧光显微镜下观察,转染后SKOV3细胞内有明显绿色荧光信号,转染率为64％;实时荧光定量PCR技术检测显示,转染后SKOV3细胞的Edg4 mRNA表达水平（0．05±0．01）明显低于转染前（0．29±0．04,P〈0．05）;SKOV3细胞上清液中LPA的含量,转染后明显低于转染前[分别为（3．0±1．0）、（7．5±2．2）μmol／L;P〈0．05];流式细胞仪检测显示,转染后SKOV3细胞的凋亡率明显高于转染前（分别为53．38％、0．51％;P〈0．05）。结论本研究成功构建了针对人Edg4基因的siRNA真核表达载体,并能较高效转染SKOV3细胞,转染后能明显抑制SKOV3细胞中Edg4 mRNA的表达,诱导卵巢癌细胞凋亡。

Vector construction and silencing effect of Edg4 gene targeted small interfering RNA in ovarian cancer cell line

OBJECTIVE: To construct the recombinant eukaryotic expression vector pRNAT-U6.1-siEdg4 which carries small interfering RNA (siRNA) of Edg4 and observe the silencing effect of Edg4 gene targeted siRNA in ovarian cancer cell line SKOV3. METHODS: The Edg4 gene-targeted hairpin siRNA sequence was designed according to the Edg4 sequence in Genbank, and the two complementary oligo nucleotide strands were synthesized and annealed and inserted into the pRNAT-U6.1 plasmid to build a recombinant Edg4 siRNA eukaryotic expression vector, which was sequenced and identified to contain the correct Edg4 siRNA sequence. The human ovarian carcinoma cell lines SKOV3 were transfected with the vector using lipofectamine method. The efficiency of transfecting cells was observed with fluorescent microscope and the mRNA expression level of Edg4 gene was detected by real time quantitative PCR. The LPA levels in cell supernatants were detected using a biochemical method. And the apoptosis of SKOV3 cells induced by the vector was evaluated by flow cytometry. RESULTS: The recombinant eukaryotic expression vector was confirmed to contain correct Edg4 siRNA sequence by PCR and sequencing. After transfection large amounts of green fluorescence were seen in plasma and nuclei of SKOV3 cells and the positive cell rates were 64%. The expression level of Edg4 mRNA in transfected SKOV3 cell line was significantly decreased (0.05 +/- 0.01vs 0.29 +/- 0.04, P < 0.05). The decrease in LPA level in the cell supernatants was revealed [(3.0 +/- 1.0) vs (7.5 +/- 2.2)micromol/L, P < 0.05]. The apoptosis rate of transfected SKOV3 was increased obviously (53.38% vs 0.51%, P < 0.05). CONCLUSIONS: We have successfully constructed the recombinant eukaryotic expression vector containing Edg4 gene targeted siRNA (pRNAT-U6.1-siEdg4). The vector could effectively transfect SKOV3 cell line, and obviously suppress the Edg4 mRNA expression and induce cell apoptosis in ovarian cancer cell line SKOV3.