Fig. 4

BRCA1-defect specific effects of PB are attributable to production of ROS and weak membrane localization of ABCG2. a 15-day Matrigel culture of mammospheres derived from HCC1937 cells and HCC1937/wt BRCA1 cells shows the selective inhibition of sphere formation in HCC1937 in the presence of 0.5 μM PB. b the ABCG2 expression in these cell lines. c ABCG2 expression in HCC1937 and HCC1937/wt BRCA1 derived mammospheres formed in presence of varying concentrations of PB shows improved membrane localization of ABCG2 after PB treatment in HCC1937/wt BRCA1 mammospheres. Cells were treated with PB on day 1, mammospheres were supplemented with growth media without PB on day 4 and mammospheres were analyzed on day 7 (d) Variation in the production of ROS in PB treated spheres of HCC1937 and HCC1937/ wt BRCA1 cell lines observable as a bright green fluorescence by DCF-DA staining. e Aldefluor assay after 48 h treatment of HCC1937 and HCC1937/wt BRCA1 cells with sub-cytotoxic concentrations of CP shows a dose dependent enrichment of ALDH1+ cells in both the cell lines. Scale = 100 μm