Research Paper Volume 4, Issue 12 pp 932—951
IL1- and TGFβ-Nox4 signaling, oxidative stress and DNA damage response are shared features of replicative, oncogene-induced, and drug-induced paracrine ‘Bystander senescence’
Figure 1. Conditioned medium from various types of senescent cells is able to induce DNA damage and DNA damage response in bystander cells. (A) Immunofluorescence detection of 53BP1, γH2AX and serine 1981 phosphorylated ATM (ATMpS1981) in BJ cells treated with senescent medium from drug-induced (DSM), oncogene-induced (OSM) or replicative (RSM) senescent BJ cells for 20 days. BJ cells treated with medium from non-senescent BJ cells (CM) were used as a control; bar 15μm. (B) Quantification of numbers of 53BP1 foci in BJ cells treated with individual senescence-conditioned media. (C) Immunoblot detection of Rb, p21, p16, total p53 and Chk2, serine 15 phosphorylated p53 and threonine 68 phosphorylated Chk2 in BJ cells treated with different types of senescence-conditioned media. GAPDH was used as a loading control. (D) Immunofluorescence detection of PML and 53BP1 foci colocalization using confocal microscope in BJ cells with different types of senescent medium.