FIGURE S3.

The majority of gefitinib-resistant persisters (GRPs) of HCC827 fluorescent ubiquitination-based cell cycle indicator (FUCCI) existed in a quiescent state and were maintained by F-box/WD repeat-containing protein 7 (FBXW7). Stable FUCCI-expressing cells were made by introducing FUCCI vector plasmid into HCC827. (A, left) HCC827 FUCCI cells were seeded in 35 mm glass bottom dishes, followed by treatment with or without gefitinib and subsequently were subjected to cell cycle analysis. The cells in G0/G1 or S/G2/M phases appear red and green, respectively. (A, right) Histograms demonstrate the distribution of the cell cycle phases before and after treatment with gefitinib. (B, left) The cell cycle profile of HCC827 FUCCI was analyzed following the knockdown of FBXW7 using reverse short interfering RNA (siRNA) transfection and gefitinib treatment for 72 h. (B, right) Histograms show the distribution of G0/G1 phase and S/G2/M phase after knockdown of FBXW7 under gefitinib treatment. Five images were taken from each group, and the cell population in G0/G1 phase as well as S/G2/M phase was counted and divided by the total number of cells. (C) The number of GRPs was decreased following the knockdown of FBXW7 in HCC827 FUCCI. Five images were taken from each group and the number of cells in G0/G1 phase as well as S/G2/M phase was counted. Scale bar indicates 50 µm.