Stable Differences in Intrinsic Mitochondrial Membrane Potential of Tumor Cell Subpopulations Reflect Phenotypic Heterogeneity

Figure 3

Differences in the Intrinsic ΔΨm of subcloned cell lines derived from primary colon and mammary tumors and from a metastatic colon tumor are linked to sensitivity to the chemoprotective agent sodium butyrate (NaB). The SW480 and MCF7 cell lines, and subclones derived from each of the cell lines, were exposed to 5 mm NaB for 72 hours. Viability was determined by MTT assay, expressed relative to untreated cells, and plotted as a function of relative ΔΨm.