Figure 3. Visual analysis of phenotypic heterogeneity using the histo-box plot.

Population distributions of STAT3 activity in Cal33 cells at the peak induction time of 15^th percentile of the untreated cells (left most histogram) are colored in blue to highlight the apparently non-responsive subpopulations. “Count” indicates the total number of cells measured. A) Linear-scaled dose-response distributions of STAT3 activity at the indicated concentrations of IL-6 show a persistent subpopulation of cells with a distribution comparable to the unstimulated cells. The well average EC50 = 3.3 ng/ml. B) Log-scaling of the same distributions in A shows that the CV of the responding cells (far right) is similar to the unstimulated cells (far left). C) Linear-scaled population distributions of STAT3 activation by OSM at the indicated concentrations also show a non-responding subpopulation at 8.68 ng/ml, but unlike IL-6 there are only a few outliers that are apparently non-responsive at 50 ng/ml and the responding cells appear to be more normally distributed. D) Log-scaling of the same distributions in C shows that the CV of the responding cells (far right) is similar to the unstimulated cells (far left).