Background & objective: Proteasome inhibitor, which can induce apoptosis in various tumor cells, is a kind of potential antitumor drug. This study was to identify the proteins involved in G(2)/M arrest of leukemia cell line HL-60 exposed to proteasome inhibitor MG132 by proteomic techniques.
Methods: Flow cytometry was used to examine cell cycle of HL-60 cells exposed to 2.5 micromol/L MG132. Nuclear extracts of HL-60 cells were prepared, and the purity was detected by light microscopy and Western blot, and the differentially expressed protein spots were determined by two-dimensional gel electrophoresis and identified with MALDI-TOF-TOF/MS.
Results: There was a distinct G(2)/M phase arrest before the apoptosis of HL-60 cells induced by 2.5 micromol/L MG132. Twenty-three differentially expressed protein spots were found between MG132-treated and control HL-60 cells; 8 nuclear proteins were identified by MALDI-TOF-TOF/MS analysis.
Conclusions: The detected proteins, such as eIF5A and splicing factor, may be involved in regulation of G(2)/M arrest of HL-60 cells. These findings will be helpful for revealing molecular mechanisms of proteasome inhibitor-induced G(2)/M phase arrest and apoptosis of leukemia cell line.