Bmi-1-siRNA Regulates the Proliferation of K562 Leukemia Cells in vitro and in vivo by PTEN/pAKT Pathway

Abstract

To investigate the effect of Bmi-1 gene silence on the proliferation ability of K562 cells in vitro and in vivo, and to explore the relation of molecular mechanism between proliferation ability of K562 cells in vitro and in vivo with PTEN/pAKT signaling pathway. The Bmi-1 small interference RNA (siRNA) sequences were transfected into K562 cells for decreasing Bmi-1 expression. The effect of Bmi-1 siRNA on the proliferation of K562 cells in vitro and in vivo was detected by MTT method and colony-forming test, the effect of Bmi-1 siRNA on the tumorogenicity of K562 cells was observed by subcutaneous inoculation of K562 cells, LY294002 and Bpv treated K562 cells in nude mice, the expression of Bmi-1, PTEN and pAKT proteins were detected by Western blot. The Bmi-1 siRNA could inhibit the proliferation activity, colony-forming and tumor-forming abilities of K562 cells. After the silence of Bmi-1 gene, the PTEN expression in Bmi-1 gene-silenced group was significantly enhanced. While the pAKT expression in Bmi-1 gene-silenced group was significantly reduced; after the K562 cells were treated with LY294002 (an inhibitor of pAKT), the pAKT expression colony-forming and tumor forming abilities were reduced in comparison with untreated K562 cells; after the K562-S1 cells were treated with Bpv (an inhibitor of PTEN), the PTEN expression decreased, while the pAKT expression, colony forming and tumor-forming abilities were restored. The Bmi-1 gene possibly involves in regulation of K562 proliferation in vivo and in vitro, the effect of PTEN/pAKT signaling pathway maybe one of molecular mechanisms mediating this regulation.