Nitric oxide inhibits the transcription of E6 gene of human papillomavirus.

High-risk human papillomavirus (HPV) is an important pathogenic factor for cervical cancer and understanding the mechanism of HPV gene transcription is important for the prevention and therapy of HPV related cervical cancer. This study aimed to investigate the role of nitric oxide (NO) in the regulation of HPV gene transcription. SiHa cells containing integrated HPV16 were treated with NO donor DETA-NO and cell proliferation and cytotoxicity were determined. HPV gene transcription was detected by real-time PCR. We found no significant cytotoxic effects on SiHa cells when the concentration of DETA-NO was less than 0.5 mmol/l. The transcription of HPV E6 gene was inhibited by DETA-NO in a dose-dependent manner and the best inhibitory effect was observed at 0.5 mmol/l DETA-NO. In addition, ERK inhibitor U0126 decreased the transcription of HPV E6 gene at the concentration of 30 μmol/l. In conclusion, NO inhibits the transcription of HPV E6 gene and probably involves MAPK signaling pathway. Keywords: SiHa cells; nitric oxide; MAPK pathway; HPV transcription.