Authenticated LNCaP and C4–2B cell lines without mycoplasma contamination were used as described in details in our previous publication[15 (link)]. The KRE (150 mg/mL kavalactones in 50% ethanol) was purchased from Gaia Herbs (Brevard, NC). Main kavalactones, including kawain, 5’,6’-dehydrokawain, yangonin, and methysticin, were isolated and purified by LKT Laboratories, Inc. (St. Paul, MN) from the KRE. Antibodies against MAO-A and tubulin were from Santa Cruz Biotechnology, Inc. (Santa Cruz, CA). Di-methylated histone H3 lysine 4 (H3K4) and H3K9 and Ki67 antibodies were purchased from Abcam (Cambridge, MA). MAO-A and LSD1 activity assay kits were from Cayman Chemical Company (Ann Arbor, Michigan).