(C) Immunoblot analysis of phosphorylated Smad2 (P-Smad2) in non-Group 3 (blue) and Group 3 (yellow) MB cell lines on the left panel. The level of total Smad2 (Smad2) was assessed and β-actin was used as a loading control. On the right panel, relative level of P-Smad2 (P-S2) were quantified to total β-actin. The p-values were determined by unpaired t-test. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. Bars represent the mean ± SD. Number of replicates is n≥3. 