Figure 5.

Identification of slow-cycling cancer cells using a lentiviral label-retaining system. (A) Illustration of principle; the lentiviral Tet-on histone-GFP strategy employed. Confocal imaging confirms the specific induction of nuclear histone-GFP expression in HeLa cells upon doxycycline treatment. (B) Schematic representation of the experimental approach to identify, isolate and characterize the slow-cycling cells, or termed as label-retaining cells (LRCs) in vivo. (C) FACS characterization of histone-GFP expression in transduced HeLa cells during 3 wks following release from doxycycline induction. (D) Immunohistochemical staining of harvested xenograft tumor tissues confirms the presence of nuclear anti-GFP immunoreactivity in these tissues.