The small molecule Retro-1 enhances the pharmacological actions of antisense and splice switching oligonucleotides

Abstract

The attainment of strong pharmacological effects with oligonucleotides is hampered by inefficient access of these molecules to their sites of action in the cytosol or nucleus. Attempts to address this problem with lipid or polymeric delivery systems have been only partially successful. Here, we describe a novel alternative approach involving the use of a non-toxic small molecule to enhance the pharmacological effects of oligonucleotides. The compound Retro-1 was discovered in a screen for small molecules that reduce the actions of bacterial toxins and has been shown to block the retrograde trafficking pathway. We demonstrate that Retro-1 can also substantially enhance the effectiveness of antisense and splice switching oligonucleotides in cell culture. This effect occurs at the level of intracellular trafficking or processing and is correlated with increased oligonucleotide accumulation in the nucleus but does not involve the perturbation of lysosomal compartments. We also show that Retro-1 can alter the effectiveness of splice switching oligonucleotides in the in vivo setting. These observations indicate that it is possible to enhance the pharmacological actions of oligonucleotides using non-toxic and non-lysosomotropic small molecule adjuncts.

Pharmacology of a Central Nervous System Delivered 2′-O-Methoxyethyl–Modified Survival of Motor Neuron Splicing Oligonucleotide in Mice and Nonhuman Primates

“…The second pathway is a nonproductive pathway that acts as a saturable sink and impairs the ability of the ASO to reach the productive pathway. It is likely that many different nonproductive sinks exist, but some have been described as intracellular lysosomes, cell-surface proteins, or even other cell types (Geary et al, 2009;Koller et al, 2011;Ming et al, 2013). Several of our results may be explained by preferential utilization of the productive versus nonproductive ASO uptake pathway.…”

Cellular Uptake and Intracellular Trafficking of Oligonucleotides: Implications for Oligonucleotide Pharmacology

“…In a collaborative effort with the group that originated these compounds, we tested several of them for the ability to enhance the actions of oligonucleotides. We were pleased to find that the agent Retro-1 produced substantial improvements of the pharmacological effects of both SSOs and classic antisense oligonucleotides (Ming et al, 2013a). In these studies, the oligonucleotides were used in ''free'' form, without the inclusion of transfection agents.…”

6BIO Enhances Oligonucleotide Activity in Cells: A Potential Combinatorial Anti-androgen Receptor Therapy in Prostate Cancer Cells

“…The identification of small molecules that facilitate ASO activity is a step in this direction. 17,48 In this study, we used small-molecule highthroughput screening to identify the kinase inhibitor 6BIO as an enhancer of the activity of potentially therapeutic PS LNA ASOs delivered by gymnosis. Pharmacological concentrations of 6BIO augmented the activity of an ASO targeted to the endogenous oncogenic miR21 in HCT116-miR21 cells (Figures 1 and 2), augmented the activity of a pre-mRNA SSO used to rescue EGFP expression in HeLa-eGPF-654 cells (Figure 3), and augmented conventional RNase H-mediated gapmer ASO gene silencing of BCL2, b-catenin, and HER3 expression in prostate cancer cells (Figure 4 and data not shown).…”