Haplotype Analysis of the Polymorphic Human Vascular Endothelial Growth Factor Gene Promoter

Abstract

The human vascular endothelial growth factor (VEGF) gene is unusually polymorphic,and there is evidence for inheritance of conserved haplotypes.One haplotype, carrying polymorphisms at −460/+405, is associated with enhanced production of VEGF in vitro. The VEGF promoter is activated by phorbol esters and, in endometrial cells, by estrogen. We have analyzed the impact of the common −460/+405 polymorphism on both basal and stimulated VEGF transcription using the human breast cancer cell line MCF7. Because the VEGF promoter is so highly polymorphic, haplotypes were established and analyzed. Carriage of the −460/+405 polymorphisms increased basal promoter activity by 71% compared with the wild-type sequence. However, this effect was dependent on colinearity with a series of further 5′ sequence polymorphisms. The −460/+405 polymorphism also increased the mean induction by phorbol ester from 5-fold to 8.5-fold. In contrast to earlier studies in endometrial cells, none of the human VEGF promoter constructs was regulated by estrogen. Overexpression of the estrogen receptor did not confer estrogen regulation to VEGF, implying cell type-specific hormonal regulation. Therefore, carriage of the −460/+405 polymorphism significantly alters VEGF promoter activity and responsiveness. This has implications for the inherited susceptibility of common diseases.