Figure 1: Dynamic monitoring of clonal evolution in cell culture with secreted luciferases.

(a) Lentiviral vectors for constitutive, puromycin-selectable cell labelling with GLuc and CLuc. (b) GLuc and CLuc activity measured in the supernatant of cultures containing parental, GLuc⁺ and/or CLuc⁺ HCT116 cells as indicated (n=3). (c) Correlation of GLuc and CLuc activity in the cell culture supernatant with cell number (n=3). (d) Correlation of GLuc/CLuc activity ratio (G/C ratio) in the cell culture supernatant with mixing ratio of GLuc⁺ and CLuc⁺ cells. G/C ratio was normalized to the 1:1 mixture (n=5). (e) Stability of the normalized G/C ratio in the supernatant of long-term cultures (n=3). (f) Parental cisplatin (CDDP)-sensitive (H460^par) and resistant (H460^res) H460 cell clones were labelled with either GLuc (GLuc⁺H460^par) or CLuc (CLuc⁺H460^res), mixed in a 1:1 ratio, cultured 3 days in the presence or absence of CDDP (arrows) and monitored daily for GLuc/CLuc activity in the culture supernatant (n=3). Shown is the G/C ratio normalized to day 1. All data are presented as mean±s.d. unless indicated otherwise. Correlation is indicated by the Pearson’s correlation coefficient r.