Figure 4

Relating ALDH activity to proteins in single cells.

(a) Comparison of single-cell protein data from ALDH^high and ALDH^low populations of MDA-MB-231 (scale bar = 50 μm). The single-cell data for each protein are processed by setting a threshold at mean + 2 s.d. of 0 cell data. Any data lower than the threshold are considered as noise and the values are reassigned as 0. P values: P < 0.05 (*), P < 0.01 (**), with P < 0.05 considered significant. NS indicates no significant statistical difference. (b) Plot of latent variables 1 (LV1) and LV2 from a model built by partial least squares discriminant analysis (PLS-DA). The values projected on each LV are their percentile weight. (c) Heat map comparing relative levels of uPA, p-S6K, VEGF, p-ERK1, IL-8 and ALDH (Aldefluor) from single cells. Single cells and proteins/ALDH activity are clustered by Euclidean distance. Experiments are repeated two times, but the data in this figure are from the same chip to lower experimental variations.