*2.1. Effect of CTX on MRC-5 Cell Differentiation with Different Stimulatory Factors under 2D Condition*

We confirmed the expression of α-SMA in differentiating myofibroblasts through immunostaining. MRC-5 cells, previously incubated with 12.5 nM CTX, were cultured in the presence of TGF-β1 (2 ng/mL) or conditioned medium (CM) from A549 cells for 3 days. There was an undetectable level of α-SMA in both control and CTX-treated unstimulated MRC-5 cells (cultured in DMEM with 10% FBS only). We found that TGF-β1 and tumor-CM induced higher α-SMA expression in untreated than in CTX-treated MRC-5 cells (Figure 1A,B). Under the same experimental condition, Calu-3-CM induced α-SMA expression in MRC-5 cells, while in the presence of CTX this marker was undetectable (Figure S1).

**Figure 1.** Myofibroblast differentiation with various stimulatory factors. (**A**) Representative immunofluorescent images of MRC-5 cells pretreated with CTX (12.5 nM) for 2 h and then incubated in DMEM (with 10% FBS), TGF-β1 (2 ng/mL), or tumor-conditioned media from A549 cells for 3 days. The control group of cells were untreated and grown in DMEM with 10% FBS only. (**B**) Quantification of α-SMA fluorescence intensity. Green fluorescence indicates α-SMA-containing stress fibers and blue fluorescence indicates the nuclei. Scale bar = 25 μm. The data are presented from three independent experiments.
