FIG 6.

γH2AX levels are reduced in synchronized LMP1-2A cells in the absence of caspase activation. (A) Graphical timeline for HK1 treatment conditions, including 36 h of serum deprivation and subsequent treatment with 5 μM etoposide in 10% serum media for 24 h. Time points for lysate harvests are indicated. (B) Immunoblot analysis of caspase 8 and PARP cleavage in HK1 cell lines. Results are compared to those from treatment with 5 μM etoposide (12 and 24 h) without prior serum starvation and arrest. As positive controls for caspase and PARP cleavage, pBabe control cells were treated with 25 μM etoposide for 24 h or 0.5 μM staurosporine (Stauro) for 8 h. (C) Immunoblot analysis of DNA damage signaling proteins and H2AX after 24 h of 5 μM etoposide treatment in HK1 cells released from serum deprivation. (D) Analysis of time points for continuous etoposide or DMSO (lanes labeled D) treatment of cells released from serum deprivation up to 24 h. Separate cell lines are grouped by perforated lines.