Abstract: Abstract: Objective To investigate the effect of Nucleophosmin (NPM1) mutations on the proliferation and apoptosis of leukemia cells. Methods The pEGFPC1-NPM1 mA plasmid vector was transfected into THP-1 cells to establish the stably expressed NPM1 mutation A protein leukemia cells (THP-1 mA). The cells transfected with pEGFPC1 plasmid (THP-1 C1) and the untreated cells (THP-1) were set as control. Cells proliferation potential was assessed by MTT assay; flow cytometry was used to detect the cell cycle and cellular apoptosis. The mRNA and protein expression of Bax and Bcl-2 were analyzed by RT-PCR and Western blot, respectively. Results Compared with the controls, growth ability of THP-1 mA cells was significantly improved. Addition, the percentage of cells in the S phase was increased significantly and that in the G1 remarkably decreased. While there was no significantly change on cellular apoptosis, and no significantly difference was observed on the expression of Bax and Bcl-2, no matter on the mRNA level or protein level. The ratio of Bax/Bcl-2 also had no significantly change. Conclusion NPM1 mutations may promote cells proliferation potential in vitro, but had no significantly influence on cellular apoptosis, which may provide a new scientific evidence for the relationship of NPM1 mutation and AML.

Key words: Key words: NPM1 mutation, leukemia, THP-1 cell line, proliferation, apoptosis