Figure 3.

Numb-regulated cell growth is mediated by Akt activation and c-Myc expression. A, Numb PRR^S knockdown induces Akt phosphorylation on Thr308. Numb knockdown was accomplished with siRNA. Akt protein and phosphorylation on Thr308 were detected by western blot. Actin was used as loading control. B, Akt inhibitor suppresses Numb PRR^S knockdown-induced cell growth. SK-Hep1 cells that were transfected with Numb siRNA and treated with Akt inhibitor MK-2206 were cultured for 7 days. Cell proliferation was assessed using MTT assay and expressed as mean cell number on day 7 ± SD (6 wells per condition). C&D, c-Myc and Oct4 mRNA levels are increased in SK-Hep1, Huh7 cell line and decreased in Huh1 cell lines following Numb knockdown. Cells transfected with Numb siRNA were cultured for 3 days. c-Myc and Oct4 mRNA expression were detected using qRT-PCR, and were normalized with the expression levels of actin. Data are expressed as relative expression level (mean ± SD for triplicate samples). E, c-Myc knockdown suppresses Numb PRR^S knockdown-induced cell growth. SK-Hep1 cells were transfected with Numb siRNA, together with or without siRNA for c-Myc and Oct4, respectively. Cell growth was measured by MTT assay.