Delivery of G6PD shRNA with PPMS polyplexes enhances oxaliplatin efficacy in CRC cells and patient-derived xenograft (PDX) model. (a) qPCR analysis of G6PD expression in DLD-1 and HCT116 cells transfected with PPMS polyplexes with G6PD shRNA or scramble plasmid DNA. (b) Immunoblotting analysis of G6PD expression in indicated cells transfected with PPMS polyplexes with G6PD shRNA or scramble plasmid DNA. (c) The tumor growth curves and the tumor weights of the mice injected with HCT116 cells were measured and recorded for each group throughout the experiment (n=5). Polyplexes were administrated through tail vein injection every 4 days, at the dose of 1.7 mg per mouse, for 4 weeks. The dose was chosen based on the maximum amount of the polymer that can be used in 200 μl buffer solution for injection. (d) The cellular ROS levels and the percentage of apoptotic cells were measured in indicated cells treated with oxaliplatin, transfected with polyplexes (shG6PD) or their combination. (e) The tumor growth curves and the weights of the PDX mice were measured and recorded for each group throughout the experiment (n=5). (f) PDX mice were weighed every 4 days for 28 days to estimate toxicity. (g) Proposed working model of this study. Data in (a, d) are presented as the mean±s.d. (n=3). **P<0.01 for indicated comparison (Student unpaired t-test).