IGROV-1/DDP cells were transfected with si-QPRT (50 nM), negative control siRNA (si-NC; 50 nM), pcDNA3.1 empty plasmid (150 nM), pcDNA3.1-QPRT (150 nM), microRNA mimic (miR-mimic; 30 nM), microRNA inhibitor (miR-inhibitor; 30 nM), scrambled miR control (miR-NC; 30 nM), or co-transfected with si-QPRT (50 nM) and miR-inhibitor (30 nM) using Lipofectamine® 3000 (Thermo Fisher Scientific, Inc.) for 48 h at 37˚C in a humidified incubator with 5% CO2. pcDNA-3.1 was purchased from Clontech Laboratories, Inc. pcDNA3.1-QPRT were synthesized by GenePharma Technology Co., Ltd, and the miR-654-3p mimic and inhibitor were purchased from Guangzhou RiboBio Co., Ltd. The sequences of si-QPRT sense, 5'-CUACUUGUGUUAUCUGUAAAU-3' and antisense, 5'-UUACAGAUAACACAAGUAGUU-3') and si-NC sense, 5'-UUCUCCGAACGUGUCACGUTT-3' and antisense, 5'-ACGUGACACGUUCGGAGAATT-3') were designed by DSIR (http://biodev.extra.cea.fr/DSIR/DSIR.html), a tool for siRNA (19 or 21 nt) and shRNA target design based on the publication by Vert et al (27 (link)) and synthesized by GenePharma Technology Co., Ltd. Except for the IGROV-1 cells, which were cultured without DDP, the untransfected IGROV-1/DDP and transfected IGROV-1/DDP cells were maintained in media containing 8 µM DDP.