Poison pen letters

Researchers at The University of Queensland were using RNAi to knock down tumor-specific proteins when they encountered an unexpected finding: the RNAi itself stimulated immunity against tumor antigens. The work suggests RNAi could be used to flag cancer cells for detection by the immune system, potentially creating a new strategy for therapeutic cancer vaccination.¹

Murine tumor cells that had been transformed with human papillomavirus (HPV), which causes cervical cancer, were treated with small hairpin RNAs designed to inactivate viral transcripts. The researchers found that the viral transcripts targeted by shRNAs were not totally destroyed, as would be expected based on previous shRNA studies. Instead, small fragments of these transcripts underwent translation, producing tiny fragments of HPV proteins. These fragments, in turn, were presented as surface antigens by the tumor cells...