Regulatory effect of LKB1 gene on expression of vascular endothelial growth factor in lung cancer cells / 第二军医大学学报

ABSTRACT

Objective: To investigate the regulatory role of LKB1 gene on expression of vascular endothelial growth factor (VEGF) in lung cancer cell line A549. Methods: DNA fragment encoding LKB1 protein was amplified by Nest-PCR from human fetal brain cDNA library and was sub-cloned into the eukaryotic expression vector pcDNA3. 1. The recombinant vector was transferred into A549 cells by Lipofectamine and screened by G418. RT-PCR and Western blot were used to study the expression of LKB1, SP1 and VEGF in A549 cells. Transcription factor SP1 was silenced by small interference RNA (siRNA); RT-PCR and Western blot were applied to examine the changes of SP1 and VEGF gene. Results: DNA sequencing analysis revealed that the open reading frame of LKB1 gene was successfully cloned into the expression vector. Stable cell line of A549 expressing exogenous LKB1 was constructed. LKB1 remarkably suppressed SP1 and VEGF expression. SiRNA targeting SP1 effectively decreased the expression of SP1 and SP1 silencing caused remarkable down-regulation of VEGF expression. Conclusion: LKB1 can negatively regulate the expression of VEGF by negatively regulate the expression of transcription factor SP1.