Figure 5.

HPV-18 E7 sensitizes PHK raft cultures to Chk1 inhibitor MK-8776. (A) Hematoxylin and eosin staining of raft cultures PHK containing empty vector (pLC), HPV-18 E6 or HPV-18 E7. The cultures were exposed to DMSO or 20 µM MK-8776 from days 8 to 12. Enlarged vacuolated cells with condensed nuclei were most prominent in the E7-expressing culture. (B) IF assay to detect BrdU (red) incorporation in the above raft cultures. Arrow heads indicate to the BrdU signals. (C) Significant inhibition of DNA replication by MK-8776 in raft cultures. Quantitative representation of total and BrdU positive nuclei from 3 microscopic fields in raft culture sections. The p values (determined by a student’s t-test using MS Excel) are indicated with ** (<0.05) or *** (<0.005). Images were captured with 20× objective.