Related Experiment Video
Updated: Feb 17, 2026
Preparation of Neutrally-charged, pH-responsive Polymeric Nanoparticles for Cytosolic siRNA Delivery
Published on: May 2, 2019
An effective tumor-inhibiting siRNA delivery platform
1Department of Pathology, University of Maryland School of Medicine, University of Maryland Baltimore, 10 S. Pine St., Baltimore, MD, 21201, USA.
Abstract:
We recently found that combining two histidine-lysine (HK) peptides effectively delivered siRNA and silenced their tumor targets. One HK peptide stabilized the siRNA within the polyplex, while the other primarily targeted the NRP-1 receptor. This receptor is often overexpressed in tumors, particularly aggressive ones. In this study, we investigated the antitumor efficacy of this delivery system against the triple-negative breast cancer cell line MDA-MB-231. These cells express high levels of NRP-1, making them a suitable model for this approach. Two tumor-promoting oncogenes, Raf-1 or PD-L1, were targeted with the systemically delivered HK peptide polyplex in an athymic mouse model. The siRaf-1 and siPD-L1 polyplexes reduced tumor size by 75% and 82%, respectively, compared with the siControl polyplex. The size reduction of these tumors, achieved through siRNA therapy, was confirmed by decreased levels of Raf-1 and PD-L1 proteins. We observed no weight differences between the therapeutic and untreated groups. These promising results should encourage further development of siRNA therapy with this carrier platform.
Insights
This study shows histidine-lysine (HK) peptide polyplexes effectively deliver siRNA to triple-negative breast cancer cells. The system significantly reduced tumor size by targeting Raf-1 and PD-L1 oncogenes.
Area of Science:
- Biotechnology
- Oncology
- Molecular Biology
Background:
- Histidine-lysine (HK) peptides can deliver siRNA, targeting tumor-specific receptors like Neuropilin-1 (NRP-1).
- NRP-1 is overexpressed in aggressive tumors, including triple-negative breast cancer (TNBC).
Purpose of the Study:
- To evaluate the antitumor efficacy of an HK peptide-siRNA delivery system against TNBC.
- To assess the targeting of oncogenes Raf-1 and PD-L1 using this system in vivo.
Main Methods:
- Systemic delivery of HK peptide polyplexes carrying siRaf-1 or siPD-L1 to MDA-MB-231 tumor-bearing athymic mice.
- Tumor size measurement and protein level analysis (Raf-1, PD-L1) post-treatment.
- Monitoring of animal weight as an indicator of systemic toxicity.
Main Results:
- siRaf-1 and siPD-L1 polyplexes reduced tumor volume by 75% and 82%, respectively, compared to siControl.
- Tumor size reduction correlated with decreased Raf-1 and PD-L1 protein expression.
- No significant weight loss was observed in treated groups, indicating good tolerability.
Conclusions:
- HK peptide polyplexes are a promising platform for targeted siRNA delivery in TNBC.
- This system demonstrates significant antitumor activity and warrants further clinical development.
- Targeting oncogenes like Raf-1 and PD-L1 with siRNA offers a viable therapeutic strategy.
Related Concept Videos
02:15Experimental RNAi
02:30siRNA - Small Interfering RNAs
In the cytoplasm, siRNA is processed from a double-stranded RNA, which comes from either endogenous DNA transcription or exogenous sources like a virus. This double-stranded RNA is then cleaved by the...
02:57Targeted Cancer Therapies
There are several types of targeted therapies against...