I n United States during 2018 an estimated 164,690 new cases and 29,430 deaths of prostate cancer. Prostate cancer ranks as the first of new cases and the second of deaths from cancer in the US during 2018. The lysine-specific demethylase 1A (LSD1/KDM1A) is the first histone demethylase discovered and it can remove mono or di-methyl groups from lysine K4 or K9 on histone H3. LSD1 expression is increased in malignant prostate cancer. Overexpression of LSD1 enhances cell growth and cancer metastasis. Therefore, we want to treat prostate cancer by inhibiting cell growth or inducing cell death or suppressing cell migration and Epithelial???Mesenchymal Transition (EMT) through the inhibition of LSD1. We synthesized a new compound (Compound X) for LSD1 inhibition, and we compared with a well-known LSD1 inhibitor, SP2509. SP2509 can inhibit cell growth in prostate cancer cell PC3 and DU145 with micromolar GI50 value (1.34 and 2.12 ?M), and Compound X can inhibit cell growth in PC3 and DU145 with submicromolar GI50 value (0.34 and 0.89 ?M) by SRB assay.