Selective silencing of viral gene expression in HPV-positive human cervical carcinoma cells treated with siRNA, a primer of RNA interference.
Selective silencing of mammalian gene expression has recently been achieved using short interfering RNA (siRNA). Synthetic siRNA targets homologous mRNA for degradation and the process is highly efficient. Here we demonstrate siRNA silencing of pathogenic viral gene expression. As a well characterized model we chose cervical carcinoma cells positive for human papillomavirus type 16. Over 90% of human cervical cancers are positive for papillomavirus and abnormal cell proliferation is driven by co-operative effects of viral E6 and E7 genes. We sought to silence HPV E6 and E7 gene expression using siRNAs to target the respective viral mRNAs. Our results indicate selective degradation of E6 and E7 mRNAs. Silencing was sustained for at least 4 days following a single dose of siRNA. E6 silencing induced accumulation of cellular p53 protein, transactivation of the cell cycle control p21 gene and reduced cell growth. In contrast, E7 silencing induced apoptotic cell death. HPV-negative cells appeared unaffected by the anti-viral siRNAs. Thus we demonstrate for the first time (i) that siRNA can induce selective silencing of exogenous viral genes in mammalian cells, and (ii) that the process of siRNA interference does not interfere with the recovery of cellular regulatory systems previously inhibited by viral gene expression.
YCR P53 Research Group, Department of Biology, University of York, York YO10 5DD, UK.
Ming
M
Jiang
Jo
J
Milner
D017209:Apoptosis / Q000502:physiology; D015153:Blotting, Western; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000378:metabolism; D017931:DNA Primers / Q000737:chemistry; D005260:Female; D015870:Gene Expression; D020868:Gene Silencing / Q000187:drug effects*; D005814:Genes, Viral / Q000187:drug effects; D006801:Humans; D009856:Oncogene Proteins, Viral / Q000235:genetics*; D027383:Papillomaviridae / Q000235:genetics*; D050725:Papillomavirus E7 Proteins; D030361:Papillomavirus Infections / Q000235:genetics* / Q000378:metabolism / Q000821:virology; D010766:Phosphorylation; D034741:RNA, Small Interfering; D022661:RNA, Untranslated / Q000494:pharmacology*; D012097:Repressor Proteins; D016160:Retinoblastoma Protein / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D014412:Tumor Virus Infections / Q000235:genetics* / Q000378:metabolism / Q000821:virology; D002583:Uterine Cervical Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000821:virology; D019014:fas Receptor / Q000378:metabolism
C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D017931:DNA Primers; C068651:E6 protein, Human papillomavirus type 16; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D034741:RNA, Small Interfering; D022661:RNA, Untranslated; D012097:Repressor Proteins; D016160:Retinoblastoma Protein; D016159:Tumor Suppressor Protein p53; D019014:fas Receptor; C059731:oncogene protein E7, Human papillomavirus type 16