Fig 8.

siRNA knockdown of Chk1, but not Chk2, significantly reduces HPV episomes in W12E cells, and aphidicolin treatment causes no additional episome loss. (A) Western blot showing specific knockdown of Chk1 and Chk2 (Cell Signaling 2G1D5 and 1C12 antibodies, respectively) following 72 h of incubation with 100 nM siRNA (Chk1 and Chk2 SMARTpool siRNA; Dharmacon). Control cells were treated with 100 nM nontargeting siRNA 2 (NT; Dharmacon). (B) Q-PCR analysis of HPV episomes following siRNA-mediated knockdown of Chk1 or Chk2. Following siRNA treatment for 72 h, W12E cells were incubated with 4 μM aphidicolin or 0.1% DMSO for 24 h. Reductions in HPV16 episome levels were observed following knockdown of Chk1 (Q-PCR, n = 6; *, P = <0.01). Aphidicolin treatment did not result in an additional decrease in the HPV copy number in cells receiving Chk1 siRNA.