Estrogen-Related Receptor Alpha Confers Methotrexate Resistance via Attenuation of Reactive Oxygen Species Production and P53 Mediated Apoptosis in Osteosarcoma Cells

Figure 4

P53 apoptosis pathway is involved in ERRα mediated MTX resistance. (a) U2OS parental and U2OS-ERRα cells (numbers 1 and 2) were treated with MTX (0-1 μM) for 48 hours; P53 protein level was assayed by western blotting. (b) U2OS parental cells were pretreated with 25 mM NAC for 2 hours followed by treatment with 1 μM MTX for 48 hours; P53 protein level was assayed by western blotting. ((c)–(e)) U2OS parental and U2OS-ERRα cells (numbers 1 and 2) were treated with 1 μM MTX for 48 hours, the expression of NOXA, XAF, and P53 was detected by QPCR. (f) U2OS parental and U2OS-ERRα cells (numbers 1 and 2) were treated with 25 mM H₂O₂ for 24 hours; P53 protein level was assayed by western blotting. Data are expressed as mean ± SD (𝑛=3) and analyzed using Student’s 𝑡-test. Asterisks indicate significant differences: ^∗𝑃<0.05, ^∗∗𝑃<0.01.

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