TGF-β and Hypoxia/Reoxygenation Promote Radioresistance of A549 Lung Cancer Cells through Activation of Nrf2 and EGFR

Figure 3

Phosphorylation of Akt was involved in Nrf2 activation in the TGF-β and hypoxic microenvironment in A549 cells. (a) Cells were treated with 1 ng/mL TGF-β and hypoxia for 2 h, followed by reoxygenation for 1 h. Phospho-Akt, total Akt, phospho-ERK, total ERK, phospho-p38 MAPK, total p38 MAPK, phospho-JNK, and total JNK levels were determined by western blotting. (b) Cells were pretreated with 10 μM LY924002 for 1 h and then subjected to combined treatment with 1 ng/mL TGF-β and hypoxia/reoxygenation. Cells were lysed 24 h later, and Nrf2, HO-1, and phospho-EGFR levels were determined by western blotting. Phosphorylated Akt and total Akt were detected at 3 h under the same experimental conditions. (c) Cells were transiently transfected with 10 nM of scramble-siRNA (si-Scr) or Nrf2-siRNA (si-Nrf2) for 24 h, followed by combined TGF-β and hypoxia/reoxygenation. Phospho-Akt and total Akt levels were determined by western blotting. (d) Cells were pretreated with 10 μM AG1478 for 1 h, followed by combined treatment with TGF-β and hypoxia/reoxygenation.

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