Fig. 4

Phototoxic effect on CSC-like subpopulation of MCF-7 cells induced by AvIR-PIT. a Representative dot plot derived from flow cytometry analysis examining the expression of cell surface CD24 and CD44 of MCF-7 cells. Black dots indicate the unsorted cells, while red dots represent the cells after magnetic cell sorting to enrich the CD24^low/CD44⁺ population. b, c Tumorsphere-formation assay and Matrigel invasion assay of unsorted and sorted CD24^low/CD44⁺ MCF-7 cells, respectively. Representative pictures of the formed tumorspheres (b, bottom) or the migrated cells in invasion assay (arrowheads) (c, bottom) are shown. The data are the means ± SEM (n = 3, *p < 0.05, **p < 0.01, Student’s t-test). d The viability of MCF-7 cells after AvIR-mediated PIT (3 J/cm²) with the indicated BioAb. The data are the means ± SEM (n = 3, **p < 0.01, Student’s t-test). e Clonogenicity of AvIR-PIT-treated surviving MCF-7 cells was evaluated by tumorsphere-formation assay. The data are the means ± SEM (n = 3, *p < 0.05, **p < 0.01, one-way ANOVA with Tukey’s test, NS; not significant)