This study was aimed to investigate the effects of bortezomib on VEGF gene expression of endothelial cell line HMEC-1, and to determine the changes of the transcriptional regulation activity of hypoxia-inducible factor 1 (HIF-1alpha) and expression intensity of Annexin A2, so as to analyze the possible mechanisms of the above expression of VEGF gene. Expression intensity of VEGF gene was determined by real-time quantitative PCR; the relative proliferation activity of cells was assayed by cell count kit CCK-8; the expression intensity of carbonic anhydrase IX (CA IX) gene was detected by RT-PCR; expression of Annexin A2 at gene and protein levels were determined by real-time quantitative PCR and Western blot respectively. The results showed that after being treated by bortezomib with 2.5, 5.0, 10 nmol/L for 12 hours, the expression intensity of VEGF gene of endothelial cell line HMEC-1 was as follows: 0.730 +/- 0.106, 0.673 +/- 0.153, 0.767 +/- 0.090 (as 1.0 was made in 0 nmol/L) (p < 0.05); the proliferation activity of cells was not significantly suppressed by bortezomib in 2.5, 5.0 nmol/L (p>> 0.05), while that was significantly suppressed by bortezomib of 10 nmol/L (p = 0.024), The results from RT-PCR showed that expression intensity of CA IX gene was conspicuously down-regulated by bortezomib in different concentrations, which suggested that the transcriptional regulation activity of HIF-1alpha was inhibited by bortezomib. And down-regulated expression of Annexin A2 protein by bortezomib in different concentrations was confirmed by real-time quantitative PCR and Western blot. It is concluded that low doses of bortezomib has no significant inhibition effect on the activity of proteasome. Bortezomib may down-regulate the expression of VEGF gene of endothelial cell through regulating the activity of HIF-1alpha and the expression of Annexin A2.