Exosome release is modulated by induction of hypoxia inducible factor. (A) MDA-MB 231 breast cancer cells were treated with 1 mM DMOG for 24 hours. Exosomes were isolated and quantitated by NTA as previously described (n = 4; ± SEM). (B) MDA-MB 231 cells were transfected with negative control (NC) siRNA or siRNA targeting HIF-1α prior to exposure to 0.1% O2 for 24 hours. Exosomes were isolated by ExoquickTM and quantitated by NTA (n = 4; ± SEM). Annotations *, **, and *** correspond with P values <0.05, <0.01 and <0.001 respectively.