Figure 4.

Sp1 transcription factor regulates the TYMS expression and subsequent capecitabine-induced death in visfatin-treated human DLD-1 CRC cells. (A) Human DLD-1 CRC cells were kept as control or treated with vehicle (PBS) or visfatin (50 ng/mL) for 6 and 12 h, and then the activity of Sp1 transcription factor was determined by transcription factor ELISA assay. (B,C) Human DLD-1 CRC cells were transfected with control- or Sp1-specific siRNA for 48 h and then kept as control or treated with visfatin for 12 h, and then the expressions of (B) mRNA and (C) protein of TYMS were examined by real-time PCR and Western blot, respectively. (D) Human DLD-1 CRC cells were transfected with control- or TYMS-specific siRNA for 48 h and then pretreated with vehicle (PBS) or visfatin (50 ng/mL) for 1 h and further kept as control or treated with capecitabine (CAP, 5 μM) for 24 h. The viability of treated cells was examined by MTT assay. Data in (A,B,D) were shown as mean ± SEM from three independent experiments. Results in (C) were representative of three independent experiments with similar results. p < 0.05 was indicated as statistically significant.