Fig. 3

TGF-β suppressed STAT1 to decrease SDH expression. A Saos-2 cells were treated with TGF-β (50 ng/ml) for 48 h and then the expression of phosphorylated JAK1, JAK1, phosphorylated JAK2 and JAK2 was determined by western blot. B Saos-2 cells were treated with TGF-β (50 ng/ml) for 48 h and then the expression of phosphorylated STAT1, STAT1, phosphorylated STAT2, STAT2, phosphorylated STAT3 and STAT3 was determined by western blot. C Immunofluorescence staining of phosphorylated STAT1 in Saos-2 and MG-63 cells with or without TGF-β (50 ng/ml) treatment. The scale bar is 50 μm. D The knockdown of STAT1 in Saos-2 and MG-63 cells was analyzed by quantitative real-time PCR. E Saos-2 or MG-63 cells were transfected with scramble siRNA (SCR), STAT1 siRNA1 or STAT1 siRNA2, and the expression of SDHD was determined by western blot. F Metabolite quantification in scramble- or shSTAT1-Saos-2/MG-63 cells treated with TGF-β (50 ng/ml). G, H Scramble- or shSTAT1-Saos-2/MG-63 cells were treated with 75 mM MTX (G) or 40 μM CIS (H) for 48 h (containing 50 ng/ml TGF-β in culture medium). Cell apoptosis was determined by flow cytometry. I Immunohistochemistry of phosphorylated STAT1 in tumor tissues from chemoresistant (CR) and chemosensitive (CS) patients. The scale bar is 100 μm. MTX, methotrexate; CIS, cisplatin