Figure 7.

Biological evaluation of G4-stabilizing activity of the selected compounds. Immunofluorescence analysis of G4 structures in U2OS cells treated for 24 h with 2 µM of the selected compounds or an equivalent amount of DMSO (negative control). As a positive control, cells were treated for 24 h with 1 µM RHPS4. Representative images of confocal sections (63×) used for the detection of G4 structures are shown. Left panels: G4 structures (red) detected by anti-G4 antibody ($\alpha$-G4). Middle panels: merged images showing G4 structures (red) and DAPI counterstained nuclei (blue). Right panels: 4× enlargements from the pictures in the middle panels. The experiment was performed in triplicate and at least 9 fields/experiments were evaluated for each condition. Scale bars are reported in the figures.