Tsang T C, Brailey J L, Vasanwala F H, Wu R S, Liu F, Clark P R, Meade-Tollin L, Luznick L, Stopeck A T, Akporiaye E T, Harris D T
Department of Microbiology, University of Arizona College of Medicine, Arizona Cancer Center, Tucson, AZ 85724, USA.
Int J Mol Med. 2000 Mar;5(3):295-300.
The success of IL-2 gene therapy in cancer is in part dependent on the development of high level IL-2 gene expression vectors. Currently, expression vectors based on the human cytomegalovirus (CMV) promoter give the highest levels of expression. We have attempted to construct new IL-2 expression vectors to test whether gene expression can be further increased. The first approach was to use the new SR-alpha promoter to control IL-2 gene expression. The second approach was to combine the Tat transcription activator gene and the HIV 1 and 2 promoters in the same construct so that the levels of gene expression can be amplified. Transient transfection results using the human colon cancer cell line SW480 showed that the SR-alpha promoter yields similar levels of activity as the CMV promoter. However, the HIV 1 and 2 promoter-based amplifier constructs produced 11 and 28 times more secreted IL-2 than the CMV promoter control. The augmented activity of the amplifier constructs was dependent on the presence of the Tat gene and the transcriptional units must be placed in the same orientation. Reducing the size of the vectors by elimination of the neomycin selectable marker did not increase the activity of the constructs.
白细胞介素-2（IL-2）基因疗法在癌症治疗中的成功部分取决于高水平IL-2基因表达载体的开发。目前，基于人巨细胞病毒（CMV）启动子的表达载体表达水平最高。我们试图构建新的IL-2表达载体，以测试基因表达是否能进一步提高。第一种方法是使用新的SR-α启动子来控制IL-2基因表达。第二种方法是在同一构建体中组合Tat转录激活基因以及HIV-1和HIV-2启动子，以便放大基因表达水平。使用人结肠癌细胞系SW480的瞬时转染结果表明，SR-α启动子产生的活性水平与CMV启动子相似。然而，基于HIV-1和HIV-2启动子的增强子构建体分泌的IL-2比CMV启动子对照多11倍和28倍。增强子构建体的增强活性取决于Tat基因的存在，并且转录单元必须以相同方向放置。通过去除新霉素选择标记来减小载体大小并没有增加构建体的活性。
