Figure 4.

5‐fluorouracil (5FU), cisplatin and etoposide increase adenovirus infection but not CMV promoter activity. (A) SUIT‐2 cells were treated with 5FU (a), cisplatin (b) or etoposide (c) for 24 h and then infected with Ad‐lacZ at a multiplicity of infection (MOI) of 10. DNA was extracted at 24 h after the infection. The viral DNA contents were quantified by real‐time polymerase chain reaction and expressed as the fold increases relative to untreated cells. Each value represents the mean ± SD of triplicate measurements. **P < 0.01. *P < 0.05, compared with control cells. (B) Post‐treatment of cells with 5FU, cisplatin and etoposide increases NK4 expression in Ad‐NK4‐infected cells. SUIT‐2 cells were infected with Ad‐NK4 at an MOI of 10 prior to treatment with 5FU, cisplatin or etoposide. NK4 levels in the culture media were measured by enzyme‐linked immunosorbent assay on postinfection day 2. Each value represents the mean ± SD of three independent samples. **P < 0.01. *P < 0.05, compared with control cells. (C) SUIT‐2 cells were transfected with NK4‐expressing plasmids and then treated with 5FU (10 µM), cisplatin (5 µM) or etoposide (10 µM) at 24 h after transfection. NK4 concentrations in culture media were measured on post‐treatment day 1. Each value represents the mean ± SD of three independent samples.