After 6 hr the medium was replaced with basal medium and the transfected cells were incubated for 24 hr. After 24 hr of incubation, the transfected cells were harvested and the cell lysates were prepared with 1 × lysis buffer (Promega, selleck chemical Madison, WI) containing 10 μg/ml aprotinin and 0·5 μm PMSF. Twenty microlitres of luciferase assay reagent (Promega)

was added to each 50-μg protein sample, and the luciferase activities were evaluated at least in triplicate. The assay results were expressed in relative luciferase activity units. The results are expressed as the average of three independent experiments ± SD. A total of 5 μg RNAs were isolated from SiHa and CaSki cells transfected with mock, E7AS, IL-32, COX-2, siCONTROL and siIL-32 using an easy-BLUE total RNA extraction

kit (iNtRon Biotechnology, Sungnam, South Korea), and the cDNA products were prepared with Moloney murine leukaemia virus reverse transcriptase (New England Biolabs, Beverly, MA). Reverse transcription–PCR (RT-PCR) analysis was performed using a Dice PCR thermal cycler (TaKaRa, Shiga, Japan) with the following primer sets: HPV E7: 5′-ATGCATGGAGATACACCTACATTGC-3′ (forward), 5′-TTATGGTTTCTGAGAACAGATGGGGC-3′ (reverse); IL-32: 5′-ATGTGCTTCCCGAAGGTCCTC-3′ (forward), 5′-TCATTTTGAGGAT TGGGGTTC-3′ (reverse); COX-2: 5′-GAAACCCACTCCAAACACAG-3′ (forward), 5′- CCCTCGCTTATGATCTGTCT-3′ (reverse); IL-1β: 5′-ATGGCAGAAGTACCTAAGCTCGC-3′ (forward), 5′-TTGACTGAAGTGGTACGTTAAACACA-3′ BAY 57-1293 in vivo (reverse); TNF-α: 5′-GTCAGATCATCTTC TCGAACC-3′ (forward), 5′-AAAGTAGACCTGCCCAGACTC-3′

(reverse); IL-18: 5′-ATAGGATCCATGGCTGCTGAACCAGTA-3′ (forward), 5′-GACAGATCTGTCTTCGTTTTGAACAG T-3′ (reverse); and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) as an internal control. Expression of proteins was analysed using Western blotting with Ribonucleotide reductase specific antibodies. The cell lysates were prepared by treating cells with a lysis buffer [0·1% SDS, 0·1% sodium deoxycholate, 1% Triton-X-100, 1 mm EDTA, 0·5 mm EGTA, 140 mm NaCl, 10 mm Tris–HCl (pH 8·0), 10 μg/ml aprotinin and 0·5 mm PMSF] on ice and centrifuged for 30 min at 11 269 g. The protein concentration of the supernatant was measured using a Bio-Rad protein assay (Bio-Rad, Hercules, CA) and 50 μg proteins were resolved on 12% SDS–PAGE. The proteins were then transferred onto PVDF membranes (Millipore, Billerica, MA) and blocked overnight with 5% skimmed milk. The antibodies used were specific to COX-2, GAPDH, p21 (Santa Cruz Biotechnology, Santa Cruz, CA), poly-ADP-ribose-polymerase (PARP; Cell Signaling Technology, Beverly, MA), cyclin E and cyclin A (BD Biosciences Pharmingen, San Diego, CA), and IL-32 (KU32-52).30 The blots were probed with enhanced chemiluminescence (GE Healthcare, Little Chalfont, UK) or WEST-ZOL Plus (iNtRon Biotechnology) Western blot detection systems according to the respective manufacturers’ instructions. Culture media were collected after incubating the transfected cells for 24 hr.