Figure 1

PFD suppresses TGF-β expression and cell proliferation. (a) Comparative TGF-β expression level in CT-26 (murine) and five human cell lines. (b) The cell growth analysis by MTT after 72 h of exposure to 5-FU, PFD, and its combination with 5-FU in CT-26 and SW-480 cells. The IC50 values for PFD were 2.73 and 2.21 mM, and for 5-FU were 54 and 500 µM in CT-26 and SW-480 cells, respectively. For combination therapy, the cells were treated with fixed doses of PFD at their IC50 values while the doses of 5-FU changed according to the doses used in 5-FU alone therapy. (c) The TGF-β expression in CT-26 and SW-480 cell lines in 5-FU, PFD, and their combination groups compared to the control. The IC50 values of PFD and 5-FU according to the MTT assay were used for the treatment of each group. In the combination group, the IC50 values of the two drugs were used (CT-26 cells; PFD IC50 value:2.73 mM, 5-FU IC50 value:54 µM, and for SW-480 cells; PFD IC50 value: 2.21 mM, 5-FU IC50 value; 500 µM. (d) The effect of 5-FU, PFD, and their combination treatment with their IC50 values on survivin mRNA expression in CT-26 and SW-480 cell lines. For combination treatment, both drugs were used in their IC50 values in each cell line. (e) Spheroid cultures of CT-26 and SW-480 cell lines, as three-dimensional models of CRC, were treated with PFD, 5-FU, and PFD + 5-FU for 72 h. (4× magnification). *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. TGF-β: Transforming growth factor beta, 5-FU: five fluorouracil, PFD: Pirfenidone.