Fig. 5: Reversal of cisplatin resistance in vitro.

A MTT assays showing reversal of cisplatin resistance by GO^PEI-siSOD1. Relative cell viability of A2780^DDP cells treated with 65 and 130 nM of GO^PEI-siSOD1 at a w/w ratio of 0.2:1 and subsequently with cisplatin (2–28 µg/mL). The graph also shows the relative cell viability of A2780 and A2780^DDP cells relative to cisplatin treatment only as a reference (n = 18). B Change of cisplatin IC₅₀ values normalized to that of A2780^DDP following treatment. C Population doubling curves of the A2780 cell line (0–96 h) under various treatment conditions. D Population doubling curves of the A2780^DDP cell line (0–96 h) under various treatment conditions. E Therapeutic efficacy and antiproliferation effect of GO^PEI-mPEG-siSOD1 in A2780 and A2780^DDP cells evaluated in ultra-low attachment plates, clonogenic and MTT assays. All values have been normalized to their respective untreated cell line control, and presented as mean ± SD (n = 3). F, G Representative images of ultra-low attachment and clonogenic assay cell culture plates. H Evaluation of total ROS, superoxide and mitochondrial membrane potential with plate reader under siSCR control and siSOD1 knockdown conditions confirmed with Western blot.