Fig. 1.

Exogenous expression of p53 downregulates the level of trefoil factor 2 (TFF2) in gastric cancer cells. A: TFF2 mRNA expression levels in gastric cancer cell lines as determined by semiquantitative RT-PCR. B: the levels of TFF2 peptide in the supernatant of gastric cancer cell lines as measured by ELISA methods. C: p53 downregulates the level of TFF2 mRNA. Gastric cancer cells were transfected with a p53 overexpression construct or control vector for 24 and 48 h. TFF2 mRNA expression was determined by RT-PCR. D: p53WT decreases the level of TFF2 peptide. Kato-III cells were transfected with p53WT plasmid or control vector for 24 and 48 h. Cell supernatant was collected and TFF2 level was measured by ELISA methods (*P < 0.05 vs. control vector). E: protein expression in Kato-III gastric cancer cells. Kato-III cells were transfected with pCMV-p53-WT or pCMV-p53R175H plasmids for 24 h. Expression of p53 and p21 proteins was assessed by Western blot. F: temperature-sensitive mutant p53val138 downregulates TFF2 mRNA expression. Stable Kato-III/p53val138 transfectants A, B, and F and 1 control vector transfectant were selected and cultured at 37.5 or 32.5°C, respectively. Messenger RNA expression of p53, p21, and TFF2 were determined by RT-PCR. G: temperature-sensitive mutant p53val138 decreases level of TFF2 peptide. Stable Kato-III transfectants were cultured at 32.5°C for 48 h. Cell supernatant was collected and TFF2 level was measured by ELISA method (*P < 0.05, #P < 0.05 vs. control vector).