Figure 5

MYC overexpression induces double-strand breaks in DNA. A) A SV40-transformed human lung cell line, WI-38 VA13, stably-expressing c-MYC, L-MYC, or N-MYC, were lyzed and immunoblots were analyzed for phosphorylated histone H2AX (anti-γH2AX) and GADPH (anti-GADPH). As a positive control for DNA damage detection, parental cells were treated with etoposide and analyzed via immunoblotting. Cell lysates were also analyzed for overexpression of MYC variants. B) The same cells lines as in A were treated with the PRKDC inhibitor, KU0060648, for 8 h, lyzed and immunoblotted for phosphorylated histone H2AX (anti-γH2AX) and γ-tubulin (anti-γ-tubulin). Signal intensities of immunoblots were quantified using ImageJ.