Abstract 4377: Novel RNAi agent can control HCV replication

Technique of RNA interference (RNAi) is important for investigating functional gene research and drug target. miRNA-122 (miR-122) is expressed abundantly in liver tissue, and it can control the Hepatitis C virus (HCV) replication. Locked Nucleic Acid (LNA)-miR-122 was shown to suppress HCV replication through inhibiting miR-122 function. Recently, anti-HCV therapy for chronic hepatitis C by LNA-miR-122 has been applied for clinical study in phase II. We developed alternative chemically modified sponge oligonucleotides (SO) for inhibition of interest miRNA function. In order to find more effective anti-viral agent, we attempted to compare the inhibition effects for viral replication between LNA-miR-122 and SO for miR-122. SO contained triplicated binding sites to miR-122, composed of either DNA or RNA, which were combined with terephthalate or glycine. We chose three types of sequences complementary to target miR-122: one perfect match sequence and two imperfect match sequences (bubble, and bulge). The effects of SOs on HCV replication were assessed by using HCV replicon cells (OR6), which contained full-genome HCV with genotype 1b and luciferase reporter genes. We compared the luciferase activity, the expression of HCV RNA, and the expression of HCV core protein in OR6 cells treated with LNA-miR-122 and several SO constructions. SO composed of terephthalate-bound RNA sequences with bulge-type imperfect complementarity was most effective in inhibiting HCV replication. By real-time qPCR analysis, the expression level of ISG15 and RIG-I in the OR6 cell treated with SO was not significantly higher than those treated with negative control (NC) or LNA. By XTT incorporation assay, the cell proliferation level in OR6 treated with SO was not also significantly affected as compared that treated with NC or LNA. We investigated novel RNAi agent termed SO that could effectively suppress HCV replication as compared LNA-miR-122. SO treatment did not activate the endogenous IFN pathway nor induce the cell mortality. Therefore SO is promising as a novel anti-vial agent. Citation Format: Masahiko Kuroda, Masakatsu Takanashi, Shinichiro Ohno, Yoshiki Murakami. Novel RNAi agent can control HCV replication. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4377. doi:10.1158/1538-7445.AM2014-4377