Figure 2

PHRF1 protects cells from genotoxic insults. (a) PHRF1-depleted U2OS cells were exposed to etoposide for 30 min and then collected for the comet assay. (b) Control and PHRF1-overexpressing U2OS cells were exposed to etoposide for 1 h and then collected for the comet assay. (c) PHRF1-depleted U2OS cells were exposed to CPT (2 μM) for 24 h or etoposide (10 μM) for 1 h and PHRF1-overexpressing cells were treated with CPT (5 μM) for 24 h or etoposide (25 μM) for 1 h for clonogenic assays. Colonies were allowed to form for 10 days and stained with crystal violet. (d) PHRF1-depleted and -overexpressing cells were treated with CPT (10 μM) and UV light (20 J/m²). Total cell extracts were collected after 2 h and immunoblotted with anticleaved caspase-3 antibody to examine apoptosis