FIGURE 6.

Anti-leukemia agents down-regulate RNF6 expression in association with PBX1 inhibition. A and B, leukemia cells (K562 and OCI-AML2) were treated with increasing concentrations of DOX (A) or 5AHQ (B) for 24 h, followed by measurement PBX1 and RNF6 expression. IB, immunoblotting. E and F, the RNF6 core regulatory region (−365/−99) was transfected into HEK293 cells for 24 h, followed by DOX (C) or 5AHQ (D) treatment with increasing concentrations for 12 h. The transcriptional activity of this regulatory sequence was analyzed by a Dual-Luciferase reporter assay system. Luci, luciferase. G and H, HA-PBX1 and Myc-PREP1 plasmids were co-transfected into HEK293 cells for 24 h, followed by DOX (G) or 5AHQ (H) treatment for 12 h. Whole cell lysates were prepared for co-immunoprecipitation (IP) and immunoblotting against specific antibodies as indicated. *, p < 0.05, **, p < 0.01, as compared with control. Error bars indicate ± S.E.