No induction of anti-viral responses in human cell lines HeLa and MCF-7 when transfecting with siRNA or siLNA

Cecilia Dahlgren, Claes Wahlestedt, Håkan Thonberg

Research output: Contribution to journalArticle

25 Scopus citations


Gene silencing by RNAi and siRNAs has become a well-used tool for researchers. Because of its relatively small size, siRNA was originally thought to avoid activation of anti-viral responses. Recent reports demonstrating so-called "off-target effects" are therefore alarming. One issue raised is that siRNA induces interferon-regulated genes at the transcriptional level. We characterize the anti-viral responses of synthetic siRNA and in vitro-transcribed siRNA by measuring the mRNA levels of IFN-β and OAS2 in HeLa cells. Transfections with both traditional and LNA-modified synthetic siRNA cause no anti-viral responses, whereas transfection with either long dsRNA or in vitro-transcribed siRNA leads to greater than 1000-fold induction of these genes. The lack of response was also demonstrated at the level of phosphorylated eIF2α, and measuring of IFN-β by ELISA in cell culture media from the human cell line MCF-7. Altogether, transfection with synthetic siRNA does not induce anti-viral responses in these two cell lines. Our results reinforce the role of siRNA as an effective tool for reverse genetics and strengthen siLNA as a tool for future therapeutic applications.

Original languageEnglish (US)
Pages (from-to)1211-1217
Number of pages7
JournalBiochemical and biophysical research communications
Issue number4
StatePublished - Mar 24 2006



  • Cell cultures
  • Interferon
  • Off-target
  • RNA interference
  • RNAi
  • siLNA
  • siRNA

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

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