Fig. 3.

Arsenic trioxide-induced downregulation of Sp and Sp-regulated proteins in KU7 cells. Effects of MG132 [A] and Z-VAD-fmk [B]. KU7 cells were treated with 10 μM arsenic trioxide alone or in combination with 10 μM MG132 or 20 μM Z-VAD-fmk for 24 hr, and whole cell lysates were analyzed by western blots as described in the Materials and Methods. [C] Effects of MG132 and Z-VAD-fmk. KU7 cells were treated as described above, and p65 and p50 proteins expressed in nuclear extracts were analyzed by western blots as described in the Materials and Methods. [D] Arsenic trioxide decreases mRNA levels of Sp and Sp-regulated genes. KU7 cells were treated with 10 μM arsenic trioxide for 24 hr and mRNA levels were determined by real time PCR as described in the Materials and Methods. Results are expressed as means ± SE for 3 replicate determinations for each treatment group, and significantly (p < 0.05) decreased mRNA levels are indicated (*).