These constructs were then transfected into A549 lung cancer cells. The results showed that the relative activity of the HMPL-504 mutation of this HIF-1α binding site reduced transcriptional activity by 36.60%. Another HIF-1α binding
site, located at -166 bp~-163 bp of the survivin core promoter was also mutated, but there was no relative difference in transcriptional activity between the normal and mutated binding site promoter constructs (data not show). These data suggest that the site locating at -19 bp ~-16 bp is one of the key cis-acting elements PLX3397 of survivin core promoter. To further prove that survivin could be induced by HIF-1α, we used RNAi to silence the expression of HIF-1α. Our results showed that the RNAi significantly decreased the expression of HIF-1α mRNA and protein in A549 cells, and that
this decrease of HIF-1α correlated with the decreased expression of survivin. This suggests that inhibiting expression of the HIF-1α gene can decrease the expression of survivin, and that HIF-1α might be an important transcription factor involved in the regulation of survivin mRNA expression. Conclusion In summary, our experimental results demonstrated that HIF-1α and survivin are highly expressed in non-small cell lung cancer and lung adenocarcinoma cell line A549 cells, and that the expression of these proteins correlated with one another. Additionally, we show that hypoxia could induce the expression of HIF-1α and survivin. Furthermore, the data presented here demonstrate that the potential binding site of HIF-1α on survivin promoter has a positive role in the regulation of transcriptional activity P005091 in vitro of the survivin gene, HIF-1α may be an important transcription factor involved in regulation of survivin expression. Acknowledgements This work was supported by grant from the National Natural Science Foundation of China (No. 30772532). References 1. Li F, Ambrosini G, Chu EY, Plescia J, Tognin S, Marchisio PC, Altieri DC: Control of apoptosis and mitotic spindle checkpoint by survivin. Nature 1998, 396 (6711) : 580–584.CrossRefPubMed 2. Li F, Ackermann
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