Figure 6.

Ectopic expression of FHL2 significantly inhibited proliferation of human neuroblastoma cells by suppressing Id2-promoted S phase entry. (A) SH–SY5Y and SK–N–SH cells were stably transfected with pcDNA3.1 empty vector, pcDNA3.1–FHL2, pcDNA3.1–Id2 or pcDNA3.1–Id2-del, and colonies were scored after selection in G418. The total number of colonies recovered from the empty vector control transfection was assigned as 100 percent. (B and C) SH–SY5Y or SK–N–SH cells were transiently transfected with the indicated plasmid combination. The pEGFP-N1 plasmid was included to identify transfected cells. Cultures were labeled with BrdU for 2 h and immunostained for BrdU by using a Cy3-conjugated secondary antibody. Cells were assessed for GFP and BrdU, and the percentage of transfected cells positive for BrdU was scored. (D) SH–SY5Y cells were transiently transfected with the indicated siRNA duplexes. After 48 h, cells were assessed for BrdU incorporation as in C. All experiments in A–D were performed in triplicate and were repeated at least three times, and the results are expressed as mean ± SEM (*P < 0.05; ^#P < 0.01; N, P > 0.05).