Fig. 5

Oct4 promoted cytoplasmic translocation of c-Myc. A Heatmap of c-Myc-differentially expressed genes (DEGs, change relative to the mean) in vector-transfected cMSCs and Oct4-overexpressed cMSCs. The top 10 highly expressed proangiogenic factors are listed. Heatmap colors indicate directionality (red: increased; blue: decreased). B RNAs extracted from vector-transfected cMSCs and Oct4-overexpressed cMSCs were subjected to real-time RT-PCR. Significantly higher levels of c-Myc target factors were detected in the Oct4-overexpressed cMSCs than in the vector-transfected cMSCs. C The c-Myc null cMSCs were transfected with Oct4 or a control vector followed by real-time RT-PCR to confirm no significant difference in the expression of c-Myc. D Tube formation ability of cMSCs transfected with Oct4 or control vector. All data are the means ± SEM; statistical significance was evaluated using the unpaired two-tailed Student’s t test with Welch’s correction. E Typical images of capillary-like net-work formation of cMSCs from these two groups. F The siRNA-transfected cells expressed significantly lower levels of VEGF signaling signals than the control. All data are the means ± SEM, and independent samples t test was used. G The mRNA expression of Oct4 and c-Myc in the cytoplasm and the nuclei of c-Myc null cMSCs were detected by real-time RT-PCR. GAPDH was served as positive control. GAPDH and c-Myc were mainly expressed in the cytoplasm, while significantly higher levels of Oct4 were detected in the nuclei than in the cytoplasm. P value for the difference between groups was calculated by the nonparametric Kruskal–Wallis test followed by a Dunn multiple comparisons test. H, RNAs extracted from cytoplasm and nuclei of cMSCs transfected with Oct4, Oct4 siRNA, or the vector were subjected to real-time RT-PCR. Significantly higher levels of c-Myc were detected in the cytoplasm than in the nuclei. All data are the means ± SEM, and independent samples t test was used (n = 10, each group). I Western blotting revealed similar protein levels of c-Myc expression in the cell lysates. oeOct4-transfected cMSCs showed more expression of cytoplasmic c-Myc than vector-transfected cMSCs, but Oct4 siRNA reversed this trend of expression, disclosing the dense expression of this factor in the nuclei. K Chromatin immunoprecipitation (ChIP) assay for the binding of Oct4 to c-Myc promoter. Anti-IgG was used as a negative control, anti-RNA-polymerase II was used as a positive control