Figure 2.

Immunoblot analysis of A549 cells treated with near‐infrared (NIR) irradiation. (a) To clarify whether NIR irradiation induces a DNA damage response that includes the checkpoint signaling pathway, the phosphorylation of DNA damage checkpoint proteins, such as histone H2AX, p53, structural maintenance of chromosome (SMC) 1 , Chk1, and ataxia‐telangiectasia mutated (ATM), was evaluated after two to six rounds of NIR irradiation at 20 J ⁄cm². (b) Time‐dependent phosphorylation of DNA damage checkpoint molecules after six rounds of treatment with 20 J/cm² NIR irradiation was observed, in the absence or presence of the ATM‐specific inhibitor KU55933, between 0 and 8 h. p‐, phosphorylated.