Figure 1

TGF-β1 treatment successfully transforms primary resting fibroblasts into CAFs.

TGF-β1 induces FSP1 expression in primary resting fibroblasts in vitro: (A). FSP1 expression is enhanced as the TGF-β1 concentration increases; (B). FSP1 expression reaches a peak at 48 hours after TGF-β1 treatment; (C). FSP1 continues to be expressed 3 weeks after TGF-β1 treatment. In parts (A), (B) and (C), the left upper panel shows the Western blot FSP1 result, the graphic shows the realtime PCR result, which is normalized to GADPH and the photos are the IF pictures (where green represents FSP1 staining). (D). TGF-β1-treated fibroblasts promote tumor growth in the xenografted mouse model. The schematic drawing shows the positions where the cells were injected; the graphic shows the tumor growth curve. The tumor size (median ± error) in the A375 plus TGF-β1-treated fibroblasts group and in the A375 group or A375 plus untreated fibroblasts at the end point is significantly different (**: P < 0.001). The picture shows the isolated tumors, where tumors in the same positions in each group are from the same mouse. The pictures in the bottom are representative fluorescence microscopy images, the greens are fibroblasts.