Novel RNA oligonucleotide improves liver function and inhibits liver carcinogenesisin vivo

Abstract

Hepatocellular carcinoma (HCC) occurs predominantly in patients with liver cirrhosis. Here, we show an innovative RNA-based targeted approach to enhance endogenous albumin production whilst reducing liver tumour burden. We designed short-activating RNAs (saRNA) to enhance expression of C/EBPα (CCAAT/enhancer-binding protein-α), a transcriptional regulator and activator of albumin gene expression. Increased levels of both C/EBPα and albumin mRNA in addition to a 3-fold increase in albumin secretion and 50% decrease in cell proliferation was observed in C/EBPα-saRNA transfected HepG2 cells. Intravenous injection of C/EBPα-saRNA in a cirrhotic rat model with multifocal liver tumours increased circulating serum albumin by over 30% showing evidence of improved liver function. Tumour burden decreased by 80% (p = 0.003) with a 40% reduction in a marker of pre-neoplastic transformation. Since C/EBPα has known anti-proliferative activities via retinoblastoma, p21 and cyclins; we used mRNA expression liver cancer specific microarray in C/EBPα-saRNA transfected HepG2 cells to confirm down-regulation of genes strongly enriched for negative regulation of apoptosis, angiogenesis and metastasis. Up-regulated genes were enriched for tumour suppressors and positive regulators of cell differentiation. A quantitative PCR and Western-blot analysis of C/EBPα-saRNA transfected cells suggested that in addition to the known anti-proliferative targets of C/EBPα, we also observed suppression of IL6R, c-Myc and reduced STAT3 phosphorylation. Conclusion We demonstrate for the first time that a novel injectable saRNA-oligonucleotide that enhances C/EBPα expression successfully reduces tumour burden and simultaneously improves liver function in a clinically relevant liver cirrhosis/HCC model.

Nanomedicine in cancer therapy: Challenges, opportunities, and clinical applications

“…This approach was successfully tested preclinically in a rat model of HCC and will hopefully enter clinical trials soon [132].…”

Recent advances in dendrimer-based nanovectors for tumor-targeted drug and gene delivery

“…Recent therapeutic interventions using siRNAs are based on RNAi, holding promising potential in terms of targeted action [85-87]. siRNAs are duplexes of 21–23 nucleotides, approximately 7.5 nm long and 2 nm in diameter.…”

Emerging cancer-specific therapeutic aptamers

“…However, currently, there is no effective treatment in pancreatic cancer. In previous studies in liver cancer, saRNA targeting C/EBPα in vivo induced a potent antitumor effect through positive regulation of C/EBPα and its downstream targets, including cyclin-dependent kinase inhibitor 1 (p21) (13). Loss of the histone demethylase KDB6B enhances the aggressiveness of pancreatic cancer via downregulation of C/EBPα (14).…”