Objective:To investigate the effect of hypoxia on vascular endothelial growth factor expression in breast carcinoma cell line(MD-MBA-435S) and its mechanism.Methods:Hypoxia culture model in vitro was established to test the expression of VEGF and HIF-1α and their correlation in MD-MBA-435S cell line.After cultured in hypoxia circumstance for a given period of time(4 hours

8 hours

12 hours

16 hours

20 hours)

VEGF expression was tested in mRNA level and protein level by RT-PCR and Western blot analysis

HIF-1 α expression tested in protein level.Cell viability in twenty hours was tested by trypan blue exclusion assay.Results:Cell survival was affected a little within 20 hours under hypoxia.Two isoforms of VEGFmRNA

VEGF-121 and VEGF165

were identified by RT-PCR

and their expressions increased after treatment of hypoxia for 4 hours.VEGF and HIF-1 α protein expressions increased equally with VEGFmRNA confirmed by immunocytochemistry and Western blot and its positive correlation was found by Pearson product-moment correlation analysis.Conclusion:VEGF gene and protein can be induced remarkably by hypoxia in breast carcinoma cell line

which is regulated mostly by transcription factor HIF-1 α.This mechanism may be involved in the malignant proliferation and transformation of breast neoplasm.