Fig. 1

Exosomes from breast cancer cells promote hypoxia signaling and contain MTA1. a. Hypoxia response element (HRE) luciferase reporter assay. MCF10A and MCF7 cells were transfected with the HRE reporter plasmid and treated with increasing concentrations of exosomes from ZR-75-1 breast cancer cells. Hypoxic response was induced using cobalt chloride and cells were assayed for luciferase activity after 18 h of treatment n = 3, **p < 0.01 one-way ANOVA. b. MCF7 cells were transfected with the HRE reporter plasmid and treated with cobalt chloride and ZR-75-1 exosomes. Cells were assayed for luciferase activity at 2, 6 and 18 h n = 3, **p < 0.01, ****p < 0.0001, Two-way ANOVA. c. Western blot analysis of CD63 and MTA1 expression in exosomes isolated from normal breast cells (MCF10A) and breast cancer cell lines (MCF7, ZR-75-1, MDA-MB-231, BT20, SK-BR-3). Coomassie staining is included as an equal loading control. d. Real-time PCR analysis of fold-change in expression of cellular MTA1 mRNA across breast cancer cell lines relative to normal breast cells (MCF10A), n = 3, **p < 0.01, ***p < 0.001, Student’s t test