Fig. 4.

Effects of tetrandrine citrate and IM on expression of p210^Bcr-Abl protein in IM-resistant K562 leukemia cells

(a, b) Tetrandrine citrate decreased Bcr-Abl protein levels of IM-resistant K562 leukemia cells in dose- and time-dependent manners. The cells were treated with tetrandrine citrate at the indicated concentrations for the indicated time, followed by Western blot analysis for Bcr-Abl; (c) IM did not affect Bcr-Abl protein in IM-resistant K562 cells. The cells were treated with IM (0–4.0 μg/ml) for 24 h, followed by Western blot analysis for Bcr-Abl. β-actin was used as a loading control; (d) Proteasome inhibitor MG132 did not prevent degradation of p210^Bcr-Abl protein induced by tetrandrine; (e) Bcr/abl fusion transcripts were reduced by tetrandrine with dose-dependence. Leukemia cells were treated with tetrandrine, and total cellular RNAs were extracted with Trizol. Bcr-Abl fusion transcripts were analyzed with RT-PCR