USP2 and prostate carcinoma: Having several potent bicyclic quinones in hand, we checked the ability of compounds 7, 9, 12 and 18 to induce apoptosis in DU145 prostate cancer cells, in which USP2 is overexpressed.14 Incubation at 6 μM concentration for two hours resulted in 3.92% apoptosis for the DMSO control, 50% for β-lapachone, ∼51% for 12, 13% for 9 and 9% for 7 (Fig. 6).