(a) U2OS cells were transfected with pcDNA3-HA containing p21, PRODH, DAO, GPR172B, PVRL4, EPN3, and LY6D. After incubation for 24 h, lysates were subjected to immunoblot analysis with the anti-HA antibody. The uncropped image is shown in Supplementary Fig. 9. (b,c) U2OS cells overexpressed with p21, PVRL4, PRODH, LY6D, DAO, EPN3, and GPR172B, selected with G418, and treated with 2 μM etoposide were subjected to SA-β-Gal staining (b) and colony-formation assay (c). The number of colonies was counted using NIH ImageJ software. (d) Hs68 cells overexpressed with p21, PVRL4, PRODH, LY6D, DAO, EPN3, and GPR172B in combination with EGFP as a transfection marker for 24 h were subjected to BrdU incorporation assay. The percentage of BrdU-positive cells in GFP-expressing cells are shown. Data are mean ± SD. Statistical significance is shown using the Student’s t-test analysis (n = 3); *P < 0.05; **P < 0.01.