title: Suppression of vascular endothelial growth factor expression at the transcriptional and post-transcriptional levels.
abstract: Gene expression is regulated at the transcriptional and post-transcriptional levels. Therefore, in order to achieve a high level of silencing, which includes minimizing any residual expression of a target gene, suppression at both the transcriptional and post-transcriptional levels is required. In this study, we describe a new method for highly efficient gene silencing that combines zinc finger protein-mediated transcriptional repression and small interfering RNA (siRNA)-mediated inhibition of post-transcriptional events. To measure the amount of gene expression under various conditions, we used a luciferase reporter gene that was driven by a variety of promoters, including that of the human vascular endothelial growth factor-A (VEGF-A) gene. We also measured expression of the endogenous VEGF-A gene. Inhibition of gene expression by each of the two individual technologies was effective, but in-depth analyses revealed residual expression of the target gene. The combination of specific zinc finger transcription factors and siRNAs greatly enhanced the silencing of the human VEGF-A gene, not only when cells were grown in the presence of normal amounts of oxygen but also under conditions of hypoxic stimulation. These results suggest that a bi-level approach to the silencing of VEGF-A expression may be clinically beneficial as part of a cancer treatment protocol.
authors.affiliation: ToolGen, Inc. 461-6, Jeonmin-dong, Yuseong-gu, Daejeon 305-390, South Korea.
authors.forename: Heung-Sun
authors.initials: HS
authors.lastname: Kwon
authors.forename: Hyun-Chul
authors.initials: HC
authors.lastname: Shin
authors.forename: Jin-Soo
authors.initials: JS
authors.lastname: Kim
mesh_terms: D015687:Cell Hypoxia; D002460:Cell Line; D020868:Gene Silencing; D017930:Genes, Reporter; D006801:Humans; D011401:Promoter Regions, Genetic; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis / Q000235:genetics*; D016335:Zinc Fingers
chemical_list: D034741:RNA, Small Interfering; D014157:Transcription Factors; D042461:Vascular Endothelial Growth Factor A