FIGURE 6.

Smad4-dependent TGF-β signaling RON expression at the transcriptional level. A, BxPC3 and Bx/Smad4 cells were pretreated with RIKI (1 μm) for 6 h followed by vehicle or TGF-β1 (5 ng/ml) in the presence or absence of RIKI for another 24 h. 100 ng of total RNA was subjected to reverse transcription and real-time PCR reaction with SYBR Green mix. The relative mRNA levels were presented as compared with untreated BxPC3 control. B, BxPC3 and Bx/Smad4 cells were transfected with full-length of RON promoter luciferase reporter construct and received the same treatment as above. Luciferase activities were measured 48 h after transfection. The data were presented as -fold changes of luciferase activities compared with untreated control. C and D, real-time reverse transcription PCR and RON promoter luciferase reporter assays performed in UK Pan-1 and UK/siSmad4 cells. Data for A–C are presented as the mean ± S.D. of three separate experiments.