Fig 3. Lentiviral tagging and flow cytometry strategy.

WT and mutant cells were induced to constitutively express blue and red, respectively, fluorescence by lentiviral transfection. Cells were then cultured alone (monocultures) or WT and mutant together (co-cultures) in 3-D culture at density ratios of 50:50, 90:10, and 10:90. The % of cells in the tumor sphere population and the size of the tumor sphere were measured by flow cytometry twice at 48 hour intervals in the presence or absence of drug.