Fig. 3.

U73122 suppressed the quantity of TGF-β₂ protein induced by ATRA in the supernatants of D407 cells. TGF-β₂ protein levels in conditioned media were measured by ELISA and normalized to cell counts (1 × 10⁶). The secretion of TGF-β₂ induced by ATRA was inhibited by U73122 (5–40 μM) in D407 cells. The suppressive effect of U73122 was enhanced with increasing concentrations of U73122, and the effect of 10 μM ATRA was completely inhibited by 40 μM U73122. Data are represented as the mean ± SEM. Statistical comparisons were performed by one-way ANOVA. *Significance versus control group (p < 0.001; n = 3 per treatment). ^#Significance versus ATRA-treated group (10 μM) (p < 0.001; n = 3 per treatment). The effects of SQ22536 on the ATRA-induced secretion of TGF-β2 in D407 Cells. Cells were pretreated with SQ22536 (5 μM, 10 μM, 20 μM and 40 μM) for 30 min, followed by exposure to ATRA (10 μM) for 16 h. There was no significant difference between the secretion of TGF-β₂ in the 5–40 μM SQ22536 + ATRA-treated group and ATRA-treated group (p > 0.05) (Fig. 4). These results indicate that SQ22536 (5–40 μM) had no suppressive effects on the secretion of TGF-β₂ induced by ATRA in D407 cells