Suppression of hypoxia-associated vascular endothelial growth factor gene expression by nitric oxide via cGMP.

Purpose: To investigate the suppressive effect of nitric oxide (NO) on vascular endothelial growth factor (VEGF) gene expression and to elucidate its mechanism of action.

Methods: Immortalized human retinal epithelial (RPE) cells, H-ras-transfected murine capillary endothelial cells, and nuclear factor-kappaB (NF-kappaB) RelA knockout 3T3 fibroblasts had VEGF gene expression stimulated by hypoxia, TPA (phorbol ester 12-O-tetradecanoylphorbol-13 acetate), and ras-transfection. The dose response and time course of inhibition of VEGF gene expression by NO were characterized by northern blot analysis, ribonuclease protection assay, and enzyme-linked immunosorbent assay.

Oncogenic H-ras stimulates tumor angiogenesis by two distinct pathways.

The switch from a quiescent tumor to an invasive tumor is accompanied by the acquisition of angiogenic properties. This phenotypic change likely requires a change in the balance of angiogenic stimulators and angiogenic inhibitors. The nature of the angiogenic switch is not known.

Chromosomal assignment of 20 cDNAs using flow-sorted spot-blot stamps.

Using a high-speed flow cytometer/sorter, we constructed spot-blot "stamps" measuring 3.5 x 2.0 cm containing 21 separate human chromosome fractions.