Fig. 2
The nanococktail showed preferred synergism in resistant cancer cells. (A and B) Optimization of the nanoparticle cocktails in terms of in vitro cytotoxicity. The NCs fabricated at varying molar ratios of Pt-LA2 to SN38-LA prodrugs were tested for their cell-killing ability against platinum-sensitive cells and platinum-resistant cells. Drugs were added to cells for 72 h of incubation, and cell viability was measured by the CCK-8 assay. (C) Confocal images representing the cellular uptake of DiI-loaded combinatorial NC by A549cisR cells after incubation for a predetermined duration at 37 °C. Hoechst 33342 (blue) and LysoTracker NDN-26 (green) were included to visualize the cell nuclei and lysosomes, respectively. The cellular colocalization of the NC and LysoTracker was evaluated by the distribution of their corresponding fluorescent signals using ImageJ software (right). Scale bars, 15 μm. The internalization of DiI-labeled NC into A549cisR cells after incubation at either 37 °C or 4 °C for 4 h (D). Histogram reveals the fold change of cellular uptake at different incubation temperatures (E). (F and G) Fluorescence-activated cell sorting (FACS) analysis to quantitatively examine the cellular uptake of the NC. Prior to incubation with the NC, cells were treated with cytochalasin D (cyto D), filipin, or chlorpromazine (CPZ) at 37 °C for 30 min (F). Histogram representing the percentage of uptake as determined by FACS analysis (G). The data are presented as the means ± SD; ***p < 0.001