Herein we provide the first evidence that salinomycin, a potassium ionophore and a human cancer stem cell inhibitor, can lower AR expression and activity, reduce protein levels of CYP17A1 and HSD3β1, the critical regulators of the androgen biosynthesis pathway, and block mTORC1 activity in PTEN-deficient prostate cancer cells. This evidence concerns the gene PTEN and cancer.