CPE-∆N increased proliferation via IGFBP2 in mouse primary cortical neurons. A) Western blot showing enhanced expression of CPE-∆N in cortical neurons transduced with 10 MOI of virus (lane 2) vs. control cells (lane 1) for 24 h. B) Western blot showing expression of IGFBP2 protein in mouse primary cortical neurons transduced with 10 and 20 MOI CPE-∆N adenovirus. Both 10 and 20 MOI CPE-∆N enhanced IGFBP2 protein levels, whereas IGFBP2 siRNA significantly reduced the protein expression of IGFBP2. C) Bar graphs showing the quantification of the Western blots in A. *P < 0.05. D) MTT assay for proliferation. CPE-∆N transduced at 10 and 20 MOI increased proliferation on d 3; that effect was blocked by IGFBP2 siRNA. One-way ANOVA with Tukey’s post hoc test. *P < 0.05, compared with controls. E) Immunocytochemistry of Ki-67+ cells in CPE-∆N–transduced mouse primary cortical neurons. Scale bar, 100 μm. *P < 0.05. F) Bar graph showing that CPE-∆N transduced at 10 and 20 MOI increased Ki-67+ cells on d 3 compared with control. Values are means ± sem.Student’s t test, n = 3. *P < 0.05, compared with control.