KDM5B-IN-4 (compound 11ad) is a novel inhibitor of lysine demethylase 5B (KDM5B), with an IC50 of 0.025 μM for KDM5B. It increases the levels of the substrate H3K4me1/2/3 in PC-3 cells by inhibiting KDM5B. Furthermore, KDM5B-IN-4 induces G2/M phase arrest in PC-3 cells and downregulates proteins in the PI3K/AKT signaling pathway. Additionally, KDM5B-IN-4 reduces tumor volume in mice with minimal organ toxicity.

KDM5B-IN-4 at a concentration of 20 μM over 72 hours specifically inhibits KDM5B and induces the production of H3K4me1/2/3 in PC-3 cells. When used in a concentration range of 0-20 μM for 72 hours, KDM5B-IN-4 not only targets KDM5B but also induces the accumulation of H3K4me1/2/3 in PC-3 cells. Additionally, KDM5B-IN-4 at concentrations ranging from 0-10 μM over 0-24 hours inhibits the proliferation and migration of prostate cancer cells, arrests the PC-3 cell cycle at the G2/M phase, and can induce apoptosis to a certain extent in PC-3 cells.

KDM5B-IN-4, administered at a dose of 50 mg/kg orally each day for 13 days, demonstrates a slightly superior antitumor effect compared to DOX. Additionally, when given at the same dosage over 25 days, KDM5B-IN-4 does not cause significant harm to mice, thereby confirming its lack of notable toxicity or side effects in vivo.