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Published on: May 2, 2019
Non-Cationic RGD-Containing Protein Nanocarrier for Tumor-Targeted siRNA Delivery
Xiaolin Yu1, Lu Xue1,2, Jing Zhao3
1Georgia Cancer Center, Augusta University, Augusta, GA 30912, USA.
Abstract:
Despite the recent successes in siRNA therapeutics, targeted delivery beyond the liver remains the major hurdle for the widespread application of siRNA in vivo. Current cationic liposome or polymer-based delivery agents are restricted to the liver and suffer from off-target effects, poor clearance, low serum stability, and high toxicity. In this study, we genetically engineered a non-cationic non-viral tumor-targeted universal siRNA nanocarrier (MW 26 KDa). This protein nanocarrier consists of three function domains: a dsRNA binding domain (dsRBD) (from human protein kinase R) for any siRNA binding, 18-histidine for endosome escape, and two RGD peptides at the N- and C-termini for targeting tumor and tumor neovasculature. We showed that cloned dual-RGD-dsRBD-18his (dual-RGD) protein protects siRNA against RNases, induces effective siRNA endosomal escape, specifically targets integrin αvβ3 expressing cells in vitro, and homes siRNA to tumors in vivo. The delivered siRNA leads to target gene knockdown in the cell lines and tumor xenografts with low toxicity. This multifunctional and biomimetic siRNA carrier is biodegradable, has low toxicity, is suitable for mass production by fermentation, and is serum stable, holding great potential to provide a widely applicable siRNA carrier for tumor-targeted siRNA delivery.
Insights
A novel protein nanocarrier delivers small interfering RNA (siRNA) beyond the liver. This engineered dual-RGD protein targets tumors, protects siRNA, and enables gene knockdown with low toxicity, advancing siRNA therapeutics.
Area of Science:
- Biotechnology
- Nanomedicine
- Molecular Biology
Background:
- Targeted delivery of small interfering RNA (siRNA) beyond the liver is a significant challenge for in vivo applications.
- Current delivery systems (cationic liposomes, polymers) face limitations including liver restriction, off-target effects, poor clearance, low serum stability, and high toxicity.
Purpose of the Study:
- To engineer a non-cationic, non-viral, tumor-targeted universal siRNA nanocarrier for enhanced in vivo delivery.
- To develop a safe and effective delivery system for siRNA therapeutics beyond the liver.
Main Methods:
- Genetic engineering of a multifunctional protein nanocarrier (26 KDa) comprising a dsRNA binding domain (dsRBD), 18-histidine for endosome escape, and dual RGD peptides for targeting.
- In vitro and in vivo evaluation of the nanocarrier's siRNA protection, endosomal escape, tumor targeting (integrin αvβ3), and gene knockdown efficacy.
- Assessment of toxicity and serum stability.
Main Results:
- The engineered dual-RGD protein nanocarrier effectively protects siRNA from degradation.
- Demonstrated efficient endosomal escape and specific targeting of integrin αvβ3-expressing cells in vitro.
- Successfully homed siRNA to tumors in vivo, leading to target gene knockdown in cell lines and tumor xenografts with low toxicity.
- The nanocarrier exhibited biodegradability, low toxicity, serum stability, and suitability for mass production.
Conclusions:
- The multifunctional, biomimetic dual-RGD protein nanocarrier is a promising platform for safe and effective tumor-targeted siRNA delivery.
- This engineered carrier overcomes limitations of current siRNA delivery systems, holding potential for widespread therapeutic applications beyond the liver.
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