Figure 7.

Collagen/α2β1 integrin inhibits doxorubicin-induced DNA damage and H2AX phosphorylation. (A–C) Collagen inhibits doxorubicin-induced DNA damage in U937 and Jurkat leukemic cell lines. The cells were pretreated for 1 h with 10 μg/ml of control IgG or with the blocking anti-α2 integrin antibody (P1E6) and then cultured on BSA or on collagen (Col) for 2 h. After removing cells in suspension, adherent cells were treated with doxorubicin (Dox) for 6 h. At the end, cells were harvested and the alkaline comet assay was performed and stained nucleoids were visualized by epifluorescence microscopy using FITC filter. (A) Representative fields corresponding to each treatment were photographed. (B,C) The intensity of DNA strand breaks was quantified using visual scoring as described under “Experimental procedures section”. The results represent mean values ± SD obtained from three independent experiments. *P < 0.05. (D,E) The cells were treated as indicated, and the levels of phosphorylated H2AX (γ-H2AX) were determined by immunoblot analysis. The β-Actin blot was used as a loading control. Blots are representative of three independent experiments.