Fig. 1

TGF-β1 overproduction in 4T1 cells promotes pulmonary metastasis. a Tgf-β1 mRNA relative expression level in cultured 4T1/RFP cells and 4T1/TGF-β1 cells, P <0.001. b Intracellular and secreted TGF-β1 protein concentration in cultured 4T1/RFP cells and 4T1/TGF-β1 cells. c Migration and invasion of cultured 4T1/RFP cells and 4T1/TGF-β1 cells treated with 1D11 were observed under the fluorescent microscopy. Migration and invasion were detected by wound healing and transwell respectively after cells were treated with 1D11 for 48 hours (left). The invaded 4T1/RFP and 4T1/TGF-β1 cells treated with 1D11 were dissolved in DMSO and OD590 values were determined using the multimode reader (right). d Bioluminescence imaging of 4T1 breast cancer lung metastasis on day 28 in vivo using IVIS, P = 0.023. (Median ± IQ range.) e Bioluminescence imaging of breast cancer metastasis in the dissected lungs. P = 0.006. (Median ± IQ range.) f Histological imaging of lung tissue sections of mice bearing 4T1/RFP tumors or 4T1/TGF-β1 tumors on day 28. Hematoxylin and eosin staining was carried out in 5 μm sections of paraffin-embedded lung tissues. Black arrow indicates metastatic tumor. g Primary tumor weight of mice bearing 4T1/RFP tumor or 4T1/TGF-β1 tumor on day 28. h Weights of tumor burden in lungs of mice bearing 4T1/RFP tumor and 4T1/TGF-β1 tumor on day 28. Results are representative of at least three experiments. *P <0.05, **P <0.01, ***P <0.001. Error bars indicate SE. TGF transforming growth factor