INFLUENCE OF HYPOXIA ON VASCULAR ENDOTHELIAL GROWTH-FACTOR AND CHORIONIC-GONADOTROPIN PRODUCTION IN THE TROPHOBLAST-DERIVED CELL-LINES - JEG, JAR AND BEWO

Growth of trophoblast tissue in early pregnancy is rapid and accomplis hed in an unusually hypoxic environment. Hypoxia has been reported to upregulate mRNA production of vascular endothelial growth factor (VEGF ), and VEGF receptors have been found on trophoblast cells. These obse rvations suggest that VEGF may have an important role in early placent ation. This study examines the influence of hypoxia on both the produc tion of the VEGF message and protein and on the production of human ch orionic gonadotrophin (hCG) protein by the cell lines JEG, JAr and BeW o. Cells were grown under normoxic and hypoxic conditions for 72 h. Th e average oxygen tension in the culture media of the hypoxic cultures (6-7 kPa) was significantly less than in the normoxic cultures (19-21 kPa). RNA was extracted and message for VEGF(121), VEGF(165) and VEGF( 189) found in all cell lines by reverse transcription and the polymera se chain reaction (RT-PCR). These messages were upregulated by hypoxia ; findings confirmed by competitive PCR for VEGF and expression of the house keeping gene GAPDH. hCG and VEGF were measured by immunoassay. Hypoxia resulted in an increase in VEGF production (P<0.05) but had in consistent effects on hCG production. In some experiments the absolute concentrations of hCG and VEGF in the culture media were noted to be significantly correlated (r>0.5, P<0.05). In addition to its role in a ngiogenesis, VEGF mag have direct effects on trophoblast cells encoura ging proliferation and invasion. These effects may be regulated in par t through oxygen supply and hCG. (C) 1997 W. B. Saunders Company Ltd.