Figure 4.

Cell culture architecture influences the response to anti-cancer drugs administered by direct inoculation: (A) Details of the four anti-cancer drugs tested in this study. Their half-maximal inhibitory concentration (IC₅₀) is listed as reported in the GDSC database for the A549 cell model (in the text referred to as “nominal IC₅₀”). (B) Changes in cell viability of sub-confluent mono-cultures of A549 cells grown on plastic substrates and exposed to the four anti-cancer drugs at their nominal IC₅₀ concentration for 72 h. GDSC database experimental conditions were reproduced in our assay. Data, shown as average ± standard error of the mean (n_replicates = 3; n_tests = 3), are normalized to the cell viability of the untreated control (NT). The symbol (***) indicates statistically significant differences from NT (p < 0.001) (one-way ANOVA followed by Dunnett post-test). (C,D) Percentage (%) of live A549 cells (C) and % cytotoxicity (D) detected in MCCs cultured for 14 d (from left to right) either on Transwell^TM supports (in ALI or in submerged conditions) or on plastic substrates (in submerged conditions) and then exposed to four anti-cancer drugs at their nominal IC₅₀ concentration for 72 h. Data are reported as average ± standard error of the mean (n_replicates = 2; n_tests = 3). The symbols (*), (**) and (***) represent significant differences from the corresponding NT (p values < 0.05, 0.01 and 0.001, respectively) (two-way ANOVA and Bonferroni post-test). (E) Histograms of the LDH activity in the experimental controls: untreated mono-cultures (NT) and positive controls (PT). A significant LDH activity was detected in supernatants harvested from PT. Data are reported as average ± standard error of the mean (n_replicates = 3; n_tests = 3). p < 0.01 and p < 0.001 indicate a significant difference from NT (t-test).