The reversal effects of 3-bromopyruvate on multidrug resistance in vitro and in vivo derived from human breast MCF-7/ADR cells.
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ABSTRACT: PURPOSE:P-glycoprotein mediated efflux is one of the main mechanisms for multidrug resistance in cancers, and 3-Bromopyruvate acts as a promising multidrug resistance reversal compound in our study. To test the ability of 3-Bromopyruvate to overcome P-glycoprotein-mediated multidrug resistance and to explore its mechanisms of multidrug resistance reversal in MCF-7/ADR cells, we evaluate the in vitro and in vivo modulatory activity of this compound. METHODS:The in vitro and in vivo activity was determined using the MTT assay and human breast cancer xenograft models. The gene and protein expression of P-glycoprotein were determined using real-time polymerase chain reaction and the Western blotting technique, respectively. ABCB-1 bioactivity was tested by fluorescence microscopy, multi-mode microplate reader, and flow cytometry. The intracellular levels of ATP, HK-II, and ATPase activity were based on an assay kit according to the manufacturer's instructions. RESULTS:3-Bromopyruvate treatment led to marked decreases in the IC50 values of selected chemotherapeutic drugs [e.g., doxorubicin (283 folds), paclitaxel (85 folds), daunorubicin (201 folds), and epirubicin (171 folds)] in MCF-7/ADR cells. 3-Bromopyruvate was found also to potentiate significantly the antitumor activity of epirubicin against MCF-7/ADR xenografts. The intracellular level of ATP decreased 44%, 46% in the presence of 12.5.25 µM 3-Bromopyruvate, whereas the accumulation of rhodamine 123 and epirubicin (two typical P-glycoprotein substrates) in cells was significantly increased. Furthermore, we found that the mRNA and the total protein level of P-glycoprotein were slightly altered by 3-Bromopyruvate. Moreover, the ATPase activity was significantly inhibited when 3-Bromopyruvate was applied. CONCLUSION:We demonstrated that 3-Bromopyruvate can reverse P-glycoprotein-mediated efflux in MCF-7/ADR cells. Multidrug resistance reversal by 3-Bromopyruvate occurred through at least three approaches, namely, a decrease in the intracellular level of ATP and HK-II bioactivity, the inhibition of ATPase activity, and the slight decrease in P-glycoprotein expression in MCF-7/ADR cells.
SUBMITTER: Wu L
PROVIDER: S-EPMC4221289 | biostudies-literature | 2014
REPOSITORIES: biostudies-literature
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