SMIP004 is a SKP2 E3 ligase inhibitor, which downregulates SKP2 and to stabilise p27. SMIP004 is a cancer cell selective apoptosis inducer of human prostate cancer cells^[1][2]. IC50 & Target: SKP2 E3 ligase^[1] In Vitro: SMIP004 decreases the levels of positive cell cycle regulators, upregulates cyclin-dependent kinase inhibitors, and results in G1 arrest, inhibition of colony formation in soft agar, and cell death^[2]. In Vivo: SMIP004 potently inhibits the growth of prostate and breast cancer xenografts in SCID mice^[2].