Fig. 7.

Small gold nanospheres and gold nanoflowers reduce de novo RNA synthesis in nucleoli of MCF7 cells. MCF7 cells were treated overnight with vehicle (V), small gold nanospheres (S), nanoflowers (F), or big gold nanospheres (B). Cells were then incubated with 5-ethynyluridine (EU) at 37 °C (green bars) to label newly synthesized RNA. For comparison, de novo RNA synthesis was determined during a 1-h heat shock at 43 °C (red bars). Pixel intensities/area were measured in at least 50 nucleoli for each data point and experiment [45]. The bar graph depicts the average + STDEV of 3–6 independent experiments. Note that heat shock, small gold nanospheres, and nanoflowers significantly inhibited RNA synthesis in nucleoli of MCF7 cells, even in the absence of hyperthermia. Significant differences were identified by one-way ANOVA/Bonferroni test; the vehicle-treated non-stress sample served as reference (*p < 0.05; **p < 0.01). Size bar is 20 μm