Estrogen influences vascular endothelial growth factor in a biphasic manner.

2003 APR 10 - (NewsRx.com & NewsRx.net) -- Estrogen influences vascular endothelial growth factor in a biphasic manner.

According to recent research from the United States, "estrogens have been shown to regulate vascular endothelial growth factor-A (VEGF-A) for physiological and patho-physiological functions. However, estrogen action on VEGF-A mRNA expression has not been completely elucidated."

"We have identified two phases of activation of VEGF-A mRNA transcription, one early and one late response, induced by 17beta-estradiol (17beta-E-2) in ER+ MCF-7 breast tumor cells, depending upon the length of exposure," commented K. Sengupta and colleagues, Veterans Administration Med Center, Cancer Research Unit.

"VEGF-A mRNA level was significantly higher than control in tumor cells after 2 hours of 17beta-E-2 exposure. Furthermore this induction was not inhibited by cycloheximide, indicating that it was a direct effect of estrogen."

"In contrast, VEGF-A mRNA expression was back at basal level in MCF-7 cells exposed to 17beta-E-2 for 6 hours. However, expression levels were again significantly augmented after 24 hours of exposure, and this induction was unaltered by cycloheximide, indicating that de novo protein synthesis was not required and like early response, it was a direct effect of estrogen," said researchers.

"The antiestrogen ICI 182,780 was a pure antagonist for the early response phase of VEGF-A mRNA induction, but it had partial but significant effect on the late response phase, further suggesting that both ...