Figure 4.

Effect on cell viability of HpI4, HpI6, trastuzumab, and their combinations at different concentrations in MDA-MB-453 cells. (a) Effect of 50 and 100 µg/mL of TZ compared to control cells (non-treated). (b,c) Effects of HpI4 (b) and HpI6 (c), either alone or in combination with 100 µg/mL of TZ, on MDA-MB-453 (330,000 cells/well) cell viability. All analyses were performed 3 days after transfection. Data represents the mean +/− SEM from at least three replicates. Statistical significance was determined using a one-way ANOVA with Dunnett’s multiple comparison test (* p < 0.05, ** p< 0.01, *** p < 0.001, **** p < 0.0001). (d) A representative image of the effect of HpI4 and HpI6 and their combinations with TZ on HER-2 protein levels. Protein extracts from MDA-MB-453 cells (330,000/well) were obtained after 48 h of transfection with 300 nM of PPRHs, either in the absence or in the presence of 100 µg/mL of TZ and analyzed by Western blot. The signal detected for tubulin was used to normalize the results. The determination was performed three times with consistent results.