ABSTRACT
Objective: To investigate the effect of nucleophosmin 1 (NPM1) mutant A on TGF-β1-induced K562 cell proliferation and AKT phosphorylation. Methods: K562 cells were infected with Ad5-NPM1 to create an NPM1 over-expression cell model. NPM1 levels were determined by ELISA and Western blot analysis. The levels of AKT and P-AKT were determined by Western blot. MTT was used to measure the proliferation of K562 cells. Results: NPM1 protein levels in K562 cells increased in an Ad5-NPM1-MOI-dependent manner. Cell proliferation and NPM1 levels in the supernatant were significantly increased in K562 cells infected with Ad5-NPM1-30 and Ad5-NPM1-100 compared to those infected with Ad5-vector-100 (P<0.01). Treatment with (10 ng/mL) TGF-β1 increased P-AKT levels, but not total AKT levels in K562 cells. TGF-β1-induced phosphorylation of AKT was significantly increased by infection of K562 cells with Ad5-NPM1-100. No significant differences were found in total AKT levels among all groups. TGF-β1 (10 ng/mL) treatment also in-creased the proliferation of K562 cells. TGF-β1-induced K562 cell proliferation was significantly increased by infection with Ad5-NPM1-100 (P<0.01). Conclusions: NPM1 improves TGF-β1-induced cell proliferation by up-regulating AKT phosphorylation levels.