Gene silencing of HPV16 E6/E7 induced by promoter-targeting siRNA in SiHa cells

Br J Cancer. 2009 Nov 17;101(10):1798-804. doi: 10.1038/sj.bjc.6605344. Epub 2009 Oct 13.

Abstract

Background: Recently, transcriptional gene silencing induced by small interfering RNA (siRNA) was found in mammalian and human cells. However, previous studies focused on endogenous genes.

Methods: In this study, we designed siRNA targeting the promoter of human papillomavirus 16 E6/E7 and transfected it into the cervical cancer cell line, SiHa. E6 and E7 mRNA and protein expression were detected in cells treated by promoter-targeting siRNA. Futhermore, cellular growth, proliferation, apoptosis and senescence were detected. Thereafter, we investigated promoter DNA methylation and histone methylation status in cells treated with promoter-targeting siRNA.

Results: We found that E6/E7 mRNA and protein were simultaneously reduced, cell growth and proliferation were inhibited and cell death, especially senescence, was remarkably increased. Meanwhile, we also found a significantly increasing histone H3-Lys9 methylation on the promoter when E6/E7 gene expression was inhibited.

Interpretation: Our findings suggest that promoter-targeting siRNA effectively and simultaneously knocks down both extraneous HPV 16 E6 and E7 at the transcriptional level, and consequently inhibits proliferation and induces death in HPV 16-infected cells. This transcriptional repression is probably induced by histone modification rather than by alteration of DNA methylation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / genetics
  • Cell Growth Processes / genetics
  • Cell Line, Tumor
  • Cellular Senescence / genetics
  • Female
  • Gene Expression Regulation, Viral
  • Gene Silencing
  • Human papillomavirus 16 / genetics*
  • Humans
  • Oncogene Proteins, Viral / genetics*
  • Papillomavirus E7 Proteins
  • Promoter Regions, Genetic
  • RNA, Messenger / biosynthesis
  • RNA, Messenger / genetics
  • RNA, Small Interfering / genetics*
  • Repressor Proteins / genetics*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Transfection
  • Uterine Cervical Neoplasms / genetics*
  • Uterine Cervical Neoplasms / therapy
  • Uterine Cervical Neoplasms / virology*

Substances

  • E6 protein, Human papillomavirus type 16
  • Oncogene Proteins, Viral
  • Papillomavirus E7 Proteins
  • RNA, Messenger
  • RNA, Small Interfering
  • Repressor Proteins
  • oncogene protein E7, Human papillomavirus type 16