Fig. 8.

β-Trcp and RSK2-mediated degradation of FOXN2 promotes cell proliferation and radioresistance in lung cancer cells. a FOXN2 knockdown cells were reconstituted with either FOXN2-WT (wild type) or FOXN2-AA mutant as indicated. b The growth curve of H1299 cells is shown. Cells were transfected with the indicated siRNAs and plasmids and then seeded at low density in plates. The cell numbers were calculated every other day. c H1299 cells were transfected with the indicated siRNAs, and plasmids were allowed to grow 2 weeks to form colonies. Representative violet staining results are shown (upper panel). The numbers of colonies were counted and shown with histograms (lower panel); **P < 0.01. d H1299 cells transfected with the indicated siRNAs and plasmids were irradiated with 2 Gy and harvested at the indicated time points. An immunostaining experiment was carried out to detect the γ-H2AX foci formation. e Quantification of γ-H2AX foci is shown in d; **P < 0.01, ***P < 0.001. f Cell survival curves derived from H1299 cells. Cells were transfected with the indicated siRNAs and plasmids and treated with the radiation dose as indicated. Percentages of surviving colonies were measured 2 weeks later. The experiments were conducted in triplicate, and the results are presented as the means ± SD