However, although our mouse model of breast cancer did not demonstrate a significant change in p-AKT protein level or ETA receptor (Figures 4B and 4D), atrasentan significantly decreased p-AKT protein levels in the heart tissues (Figures 4B and 4D), suggesting that atrasentan significantly blocked the endothelin signaling in our breast cancer–injected mice. Here, AKT1 is linked to breast carcinoma.