Figure 3. JSI-124 increased the sensitivity of K562/A02 cells to adriamycin through down-regulation of mdr1.

(A) JSI-124 inhibited phosphorylation of STAT3 and the proliferation of K562/A02 cells. Cells were cultured in medium containing 1 µg/ml adriamycin and different concentrations of JSI-124, and proliferation was detected with [³H] thymidine incorporation. STAT3 and pY705STAT3 were measured by western blotting. (B) The cells were cultured with different concentrations of adriamycin combined with 1 µM of JSI-124 followed by the CCK-8 assay. (C) JSI-124 inhibited the transcription of mdr1 and expression of P-gp. After being treated with JSI-124 as indicated concentrations for 24 h, mRNA level of mdr1 in K562/A02 cells was detected using real time-PCR. P-gp was examined by western blotting after being treated for 36h. (D) JSI-124 increased the accumulation of adriamycin into K562/A02 cells. Cells were pretreated with JSI-124 for 24h, and then treated with adriamycin or rhodamine 123 for 90min. Fluorescence intensity were determined by flow cytometry.