uPAR is essential for MMS-induced DNA SSB signaling and DNA repair.

<p>A. Growth arrested SiCo and uPARsi -nucleofected human VSMC were treated with 1.2 mM MMS for indicated time points. Phosphorylation of Chk1 and Chk2 kinases was detected by western blotting. B. HEK 293 cells were infected with control lentivirus or uPAR-FLAG-expressing virus, and stimulated with 1.2 mM MMS for indicated time points. Phosphorylation of Chk1 and Chk2 kinases was detected by western blotting. C. WT and uPAR−/− mouse VSMC were treated with MMS for 20 min on ice to induce DNA damage. After H₂O₂ removal VSMC were allowed to repair DNA for 4 hrs. Comet tails were quantified as described in the Materials and Methods. D. WT and uPAR−/− mouse VSMC were treated with different concentrations of MMS for 20 min to induce DNA damage. The number of viable cells was calculated 24 hrs after DNA damage using 5(6)CFDA as described in Material and methods.