Figure 3.

Lower FOXO1 transcription associated with poor prognosis. (A) Expression of the FOXO1 was increased along with human (left panel) and mouse (right panel) B lymphocyte development. Each B-cell group is represented by a bar and is color-coded according to the subgroups it belongs to. (B) Expression of the FOXO1 was constitutively activated among B-ALL samples, with the highest expression in ETV6-RUNX1 subtype. (C) Luciferase reporter gene assay of MEIS1–FOXO1 transcription activity. HEK-293T cells were transiently transfected with pGL3 construct (luciferase gene with FOXO1 binding sites), pcDNA construct [empty vector, wild-type FOXO1 [FOXO1^wt], MEIS1–FOXO1, or truncated FOXO1 [FOXO1^tr]], and pGL-TK (Renilla luciferase). (D) Expression of the FOXO1 among 35 B-ALL cases. RT-PCR was performed to quantify the FOXO1 transcription, and the quantification was expressed as relative to internal GAPDH control. The red dot represented the B-ALL case with MEIS1–FOXO1 fusion gene. Statistical significance, determined using one-way ANOVA test (A,B) or two-sided unpaired t-test (C), is indicated by ****P < 0.0001.