Modulation of endogenous VEGF-A expression under hypoxia by using artificial transcription factors.

The vascular endothelial growth factor A (VEGF-A) gene is an attractive therapeutic target because both activation and repression of the gene are useful for treatment or cure of many diseases related to abnormal angiogenesis. To modulate the endogenous gene expression artificially, we previously designed a six-finger AZP to recognize a 19-bp DNA in the VEGF-A gene, and fused the AZP with a nuclear localization signal and a repressor domain to generate an artificial transcription factor (ATF). Using the ATF, we demonstrated efficient modulation of the VEGF-A expression. In the present study, we evaluate the ability of the ATF to modulate the gene expression under hypoxic conditions. Enzyme-linked immunosorbent assays (ELISA) for VEGF-A protein in the culture medium revealed that the gene-delivered ATF also repressed the expression of the endogenous VEGF-A gene under hypoxia.