Effect of down-regulated adenosine triphosphate binding cassette transporter G2 gene on human breast cancer docetaxel resistant cell line BT549/Docetaxel

Objective Down people docetaxel-resistant breast cancer cell lines expressing multidrug resistance gene adenosine triphosphate binding cassette transporter G2 (ABCG2) BT549/Docetaxel,testing alter their biological properties.Methods moderate concentrations,to establish the role of law intermittent docetaxel in human breast cancer cell lines resistant to BT549/Docetaxel,ABCG2 expression vector construct pRNAT-U6.2/Lenti small interfering RNA (siRNA) transfection BT549/Docetaxel,using the methyl thiazol tetrazolium (MTT) assay after transfection resistance index of cells,high performance liquid chromatography (HPLC) intracellular concentration of docetaxel.Methods Using moderate concentrations 0.08 mg/L,to establish the role of law intermittent docetaxel in human breast cancer cell lines resistant to BT549/Docetaxel,constructed of ABCG2 pRNAT-U6.2/Lenti siRNA expression vector was transfected BT549/Docetaxel,using the MTT assay after transfection cells the resistance index,HPLC intracellular concentration of docetaxel.Results Infection ABCG2si2,ABCG2si1,BT549/Docetaxel cells ABCG2siC after BT549/Docetaxel compared with uninfected cells and ABCG2 mRNA relative expression of β-actin levels were 0.11 t± 0.02,0.26 ± 0.01,0.88 ± 0.03,0.92± 0.02.Infection ABCG2si1,the ABCG2si2 cells reduce ABCG2 expression and control ABCG2siC,BT549/Docetaxel statistically significant compared (P ＜ 0.05),respectively,a decrease of 71.7％ and 88.0％.Four cells were Western bloting showed different ABCG2 protein levels,ABCG2si1,ABCG2 si2 inhibit the expression of the protein,the latter effect is significant (P ＜ 0.05).By MTT assay,infection ABCG2si2,ABCG2siC cells and uninfected cells BT549/Docetaxel 50％ inhibitory dose (IC50) of Docetaxel respectively 31.12,69.55,76.21 mg/L,the resistance index were 8.13,18.16,19.90.Which significantly increases the sensitivity of the former and the latter two Docetaxel compared (P ＜ 0.05).HPLC intracellular docetaxel,the content of the drug within the cells of 7.9 ng/106 BT549/Docetaxel cells infected in the content of intracellular drug BT549/Docetaxel 66.7 ng/106 cells,normal culture medium after 4 h,the content within BT549/Docetaxel cells after infection drugs for 53.1 ng/106 cells,the difference was statistically significant (P ＜ 0.05).Conclusion By ABCG2 gene regulation and breast cancer resistance can be closely related to the reversal of drug resistance BT549/Docetaxel. Key words: Docetaxel ;  Drug resistance ;  Breast cancer