[Influence of As(2)O(3) on proteasome beta(1)-subunit in NB4 cells].

This study was aimed to explore the correlation between effects of arsenic trioxide on NB4 cell differentiation and the change of beta(1)-subunit of 26S proteasome. NB4 cell in 0.5 micromol/L As(2)O(3) was incubated for 24 hours and 48 hours, then total protein was extracted, expressions of subunit beta(1) and PML-RARalpha fusion protein were determined by Western blot. The results indicated that the expression of 26S proteasome beta(1)-subunit increased after incubation with As(2)O(3) for 24 hours, but after culture with As(2)O(3) for 48 hours, the expression of beta-subunit decreased to the baseline. Meanwhile, the expression of PML-RARalpha fusion protein obviously decreased after 24 hours, and kept low level at 48 hours. It is concluded that the expression of 26S proteasome beta(1)-subunit increases after exposure to As(2)O(3). Increment of 26S proteasome beta(1)-subunit may be associated with the degradation of PML-RARalpha fusion protein and plays roles in the differentiation and apoptosis of NB4 cells.