Prostate cancer is the second most frequently diagnosed cancer and the sixth most commonly fatal cancer in men worldwide. Endothelin-1 (ET-1), produced by the prostate epithelia, likely plays an important role in the progression of prostate cancer. ET-1 has been previously reported in prostate and other organs. However, ET-1 expression in Prostate cancer cell lines has not been described. Therefore, we have used Western Blot to demonstrate ET-1 expression in breast cancer cell lines (LNCap cell line, PC3 cell line and DU145 cell line). The results suggest the expression of ET-1 is significantly high expressed in PC3 cell line. Moreover, knockdown of ET-1 gene with siRNA can effectively repress the cell proliferation and the cell cycle was blocked in G1/G2 phase. Knockdown of ET-1 gene can affect cell invasion, which is confirmed by cell invasion and migration related genes using west blot (-catenin, Ecadherin, RhoC and RhoA). Characterization of the role of ET-1 in the development of tumors could lead to a better understanding of the changes occurring at the molecular level during the development and progression of primary human Prostate cancer.