Fig. 2

TGF-β suppressed succinat dehydrogenase to promote chemo-resistance. A Metabolite quantification by ¹H-NMR. Results show the metabolite ratio in Saos-2/MG-63 cells after treatment with TGF-β (50 ng/ml). B, C The expression of SDHD in Saos-2 and MG-63 cells after treatment with TGF-β (50 ng/ml) was determined by quantitative real-time PCR (B) and western blot (C). D The knockdown of SDHD in Saos-2 and MG-63 cells was analyzed by quantitative real-time PCR. E, F Saos-2 and MG-63 cells were transfected with scramble siRNA (SCR), SDHD siRNA1 or SDHD siRNA2, and treated with 75 mM MTX (E) or 40 μM CIS (F) for 48 h. Scramble-Saos-2/MG-63 cells were used as control. Cell apoptosis was determined by flow cytometry. G Saos-2 and MG-63 cells were treated with MTX (75 mM) plus succinate (20 mM) for 48 h. Cell apoptosis was determined by flow cytometry. H The same as G, except that Saos-2 and MG-63 cells were treated with CIS (40 μM) plus succinate for 48 h. I Immunohistochemistry of SDHD in tumor tissues from chemoresistant (CR) and chemosensitive (CS) patients. The scale bar is 50 μm. MTX, methotrexate; CIS, cisplatin