Prolonged gene silencing in hepatoma cells and primary hepatocytes after small interfering RNA delivery with biodegradable poly(β-amino esters)
Article first published online: 12 MAY 2008
Copyright © 2008 John Wiley & Sons, Ltd.
The Journal of Gene Medicine
Volume 10, Issue 7, pages 783–794, July 2008
How to Cite
Vandenbroucke, R. E., De Geest, B. G., Bonné, S., Vinken, M., Van Haecke, T., Heimberg, H., Wagner, E., Rogiers, V., De Smedt, S. C., Demeester, J. and Sanders, N. N. (2008), Prolonged gene silencing in hepatoma cells and primary hepatocytes after small interfering RNA delivery with biodegradable poly(β-amino esters). J. Gene Med., 10: 783–794. doi: 10.1002/jgm.1202
- Issue published online: 16 JUN 2008
- Article first published online: 12 MAY 2008
- Manuscript Accepted: 26 MAR 2008
- Manuscript Revised: 28 FEB 2008
- Manuscript Received: 7 NOV 2007
- biodegradable polymer;
- liver cells;
- poly(β-amino esters);
- prolonged gene silencing;
- siRNA delivery
Small interfering (si)RNA mediated inhibition of oncogenes or viral genes may offer great opportunities for the treatment of several diseases such as hepatocellular carcinoma and viral hepatitis. However, the development of siRNAs as therapeutic agents strongly depends on the availability of safe and effective intracellular delivery systems. Poly(β-amino esters) (PbAEs) are, in contrast to many other cationic polymers evaluated in siRNA delivery, biodegradable into smaller, nontoxic molecules.
Methods and Results
We show for the first time that PbAE : siRNA complexes, containing 1,4-butanediol (PbAE1) or 1,6-hexanediol (PbAE2) diacrylate-based polymers, induced efficient gene silencing in both hepatoma cells and primary hepatocytes without causing significant cytotoxicity. Furthermore, carriers that slowly release the siRNA into the cytoplasm and hence induce a prolonged gene silencing are of major clinical interest, especially in fast dividing tumour cells. Therefore, we also studied the duration of gene silencing in the hepatoma cells and found that it was maintained for at least 5 days after siRNA delivery with PbAE2, the polymer with the slowest degradation kinetics.
From the time-dependent cellular distribution of these PbAE : siRNA complexes, we suggest that the slowly degrading PbAE2 causes a sustained endosomal release of siRNA during a much longer period than PbAE1. This may support the hypothesis that the endosomal release mechanism of PbAE : siRNA complexes is based on an increase of osmotic pressure in the endosomal vesicles after polymer hydrolysis. In conclusion, our results show that both PbAEs, and especially PbAE2, open up new perspectives for the development of efficient biodegradable siRNA carriers suitable for clinical applications. Copyright © 2008 John Wiley & Sons, Ltd.