Abstract: BACKGROUND ＆ AIM: To study the underlying molecular mechanisms by which ERK1/2 kinase modulated the expression of vascular endothelial cells growth factor (VEGF) in lung cancer cells. MATERIALS AND METHODS: PD98059, the special inhibitor of ERK1/2, was used to inhibit the phosphorylation of ERK1/2. Western blot was used to evaluate the expression of ERK1/2. Transcription factor Sp1 gene was silenced by small interfering RNA technology. SEAP assay was used to detect the transcription activity of Sp1. RT_PCR was applied to examine the expression status of VEGF and Sp1. RESULTS: Western blot and RT_PCR results proved that PD98059 inhibited the phosphorylation of ERK1/2. The expression of VEGF gene was decreased associated with the inhibition of ERK1/2 kinase. The transcription activity of Sp1 was down_regulated by PD98059. SiRNA targeting Sp1 effectively decreased the expression of itself and VEGF. CONCLUSION: In lung cancer cells the expression of VEGF might be regulated by ERK1/2 signal pathway, and partly depended on the activity of transcription factor Sp1.

Key words: lung cancer, VEGF, ERK1/2, Sp1