The Role of Enhanced Chemotherapy Sensitivity on Drug Resistance of the Small Cell Lung Cancer Cells by Up-regulated Sp1

Abstract: In order to find the chemotherapy sensitivity of how transcription factor Sp1 influence the etoposide (VP-16) resistance of small cell lung cancer cells， we transfected the expression type human Sp1 plasmid to H446/VP cells to enhance the expression of Sp1. Transfected Sp1 plasmid to VP-16 resistance small cell lung cancer cell， H446/VP mediated by liposome. The microculture tetrazolium (MTT) assay was used to measure the half inhibiting concentration (IC50); AO/EB double fluorescent staining was applied to measure the death rate; RT-PCR and Western blot were used to measure the mRNA and protein expression of Sp1， topoisomerase II (Topo IIα， Topo IIβ). It was found that the IC50 of H446/VP-Sp1 cell was obviously lower than H446/VP cell; The death rate of H446/VP-Sp1 cell increased significantly by comparing with H446/VP cell. It was showed that in both of the level of mRNA and protein， the expression of Sp1， Topo IIα was increased in H446/VP-Sp1 cell， while the Topo IIβ expression had no obvious change. It was showed that the up-expression of Sp1 can enhance the expression of Topo IIα in the drug resistance of small cell lung cancer cells. It offered more targets and increased sensitivity for topoisomerase inhibitor.
    

CSTR: 32200.14.cjcb.2007.04.0030