A) Detection of labeled DNA-Pt in U2OS cells. B) Schematic representation of a strategy for enhancing the detection of DNA-Pt in cells. C) Detection of labeled DNA-Pt in U2OS cells subjected to pre-extraction. Cells were treated with APPA (250 mm for 3 h). Zoomed images are 3x . Scale bar, 20 μm. Unt., untreated.