Figure 7.

Blockade of miR-155 expression abrogates bortezomib-mediated decrease in SH-2 containing inositol 5’-polyphosphatase 1 (SHIP1) levels. Human HEK-293T cells were treated in vitro for 24 h with increasing concentrations of bortezomib (2, 4, 6, 8, 10 nM). The cells were collected and analyzed for miR-155 expression by RT-PCR and for SHIP1 protein level by Western blotting. (A) Western blot shows lack of SHIP1 expression in 293T cells in comparison with T1 cells. (B) The expression of miR-155 in 293T cells is shown upon bortezomib treatment at the indicated concentrations. 293T cells were transfected with 100 µg of SHIP1 3’-UTR luciferase reporter plasmid and treated with increasing concentrations of bortezomib as indicated in combination with or without 200 pmoles of anti-miR-155. (C) Bortezomib’s dose dependent effect on SHIP1-luciferase reporter activity is shown in 293T cells. (D) Bortezomib’s effects on SHIP1-luciferase activity in 293T cells in the presence or absence of anti-miR-155 are shown. Data are mean values ± SD from three independent experiments with triplicates; ^* p < 0.0148 compared to DMSO, ^** p < 0.0001 compared to DMSO or anti-miR-155 (ANOVA, one-way).