Abstract 2764: Small activating RNA induced expression of VHL gene in renal cell carcinoma

Abstract

Abstract Recent studies have reported that chemically synthesized double-stranded RNAs (dsRNAs), also known as small activating RNA (saRNAs), can specifically induce gene expression by targeting promoter sequences in a mechanism termed RNA activation (RNAa). In the present study, we designed four candidate dsRNAs targeting the Von Hippel-Lindau (VHL) gene promoter. Among these dsRNAs, dsVHL-821 significantly inhibited cell growth by up-regulating VHL at both the mRNA and protein levels in renal cell carcinoma 769-P cells. Functional analysis showed that dsVHL-821 induced apoptosis by increasing p53, decreasing Bcl-xL, activating caspase 3/7 and poly-ADP-ribose polymerase in a dose-dependent manner. Chromatin immunoprecipitation analysis revealed that dsVHL-821 increased the enrichment of Ago2 and RNA polymerase II at the dsVHL-821 target site. In addition, Ago2 depletion significantly suppressed dsVHL-821-induced up-regulation of VHL gene expression and related effects. Consistent with previous studies on RNAa of other genes, single transfection of dsVHL-821 caused long-lasting (14 days) VHL up-regulation. Furthermore, the activation of VHL by dsVHL-821 was accompanied by an increase in dimethylation of histone 3 at lysine 4 (H3K4me2) and acetylation of histone 4 (H4ac) and a decrease in dimethylation of histone 3 at lysine 9 (H3K9me2) and lysine 27 (H3K27me2) in the dsVHL-821 target region. Taken together, these results demonstrate that dsVHL-821, a novel saRNA for VHL, induces the expression of the VHL gene by epigenetic changes, resulting in inhibition of cell growth and induction of apoptosis. Targeted activation of VHL by dsVHL-821 may be explored as a novel treatment of renal cell carcinoma. Citation Format: Jong Soon Kang, Moo RIm Kang, Ki Hwan Park. Small activating RNA induced expression of VHL gene in renal cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2764.