Figure 3

Effect of ALDH sorting on ALDH activity and sphere-forming efficiency in H28, H2052 and Meso4 cell lines after in vitro expansion. (A) The ALDH activity of the in vitro-expanded ALDH^high and ALDH^low fractions was determined by Aldefluor assay. P₀ represents the ALDH activity of the non-sorted cell lines, whereas P₁-P₄ accounts for the average ALDH activity measured after 4 passages of in vitro expansion. (B) Representative FACS analyses of ALDH activity of ALDH-sorted fractions of H2052 measured at every passage. (C) The sphere-forming efficiency was also assessed after the in vitro expansion of the ALDH^high and ALDH^low fractions. Cells were grown under anchorage-independent cell culture conditions and were counted on day 7 for all cell lines and were used to determine the sphere-forming efficiency as described in the Methods. (D) Representative images of the sphere formation of ALDH-sorted fractions of H2052 taken at every passage. Results reflect the means and SDs of 3 independent experiments for each cell line. Results were statistically significant if p <0.05 (*p <0.05, **p <0.01).