gH625 Cell-Penetrating Peptide Promotes the Endosomal Escape of Nanovectorized siRNA in a Triple-Negative Breast Cancer Cell Line

Abstract

The use of small interfering RNA (siRNA) to regulate oncogenes appears as a promising strategy in the context of cancer therapy, especially if they are vectorized by a smart delivery system. In this study, we investigated the cellular trafficking of a siRNA nanovector (called CS-MSN) functionalized with the cell-penetrating peptide gH625 in a triple-negative breast cancer model. With complementary techniques, we showed that siRNA nanovectors were internalized by both clathrin-and caveolae-mediated endocytosis. The presence of gH625 at the surface of the siRNA nanovector did not modify the entry pathway of CS-MSN, but it increased the amount of siRNA found inside the cells. Results suggested an escape of siRNA from endosomes, which is enhanced by the presence of the peptide gH625, whereas nanoparticles continued their trafficking into lysosomes. The efficiency of CS-MSN to inhibit the GFP in MDA-MB-231 cells was 1.7-fold higher than that of the nanovectors without gH625.

Nanoscopy for endosomal escape quantification

“…Overview of different types of quantification methods and how these can be achieved using nanoscopy and confocal microscopy, including information on throughput and disadvantages of the methods. resolution microscopy has been used to image nanoparticles bursting out of endosomes with STORM (left) (96) and SIM (right) (117). Reprinted (adapted) with permission from ref.…”

Cell Penetrating Peptides: Applications in Tumor Diagnosis and Therapeutics

“…Small interfering RNA (siRNA) is noncoding RNA that stops the expression of certain genes by degrading mRNA created during translation; this ultimately prevents ribosomes from translating the mRNAs into functional proteins [85][86][87][88][89] . SiRNAs shows great potential at treating cancer; however, their adaption in clinical settings has been slow due to a lack of safe and effective vehicle for delivery.…”

“…85 Cell-penetrating peptides show promise in pre-clinical research to be safe and effective vehicles for siRNA to target tumors. Many peptides, such as CPP33, gh625, PD-L1, PEG-SS-PEI and many others, have been used in combination with siRNA to target various forms of cancer to great success in animal models [85][86][87][88][89] . Not only did these peptides coupled to siRNA increase the ability to enter tumor cells, but they helped aid in endosomal escape of the siRNAs once they were internalized into cells [85][86][87][88][89] .…”

“…Many peptides, such as CPP33, gh625, PD-L1, PEG-SS-PEI and many others, have been used in combination with siRNA to target various forms of cancer to great success in animal models [85][86][87][88][89] . Not only did these peptides coupled to siRNA increase the ability to enter tumor cells, but they helped aid in endosomal escape of the siRNAs once they were internalized into cells [85][86][87][88][89] . CPP33 loaded with siPLK1 (an siRNA to target A549 lung cancer cells) exhibited additional endosomal escape but also prolonged blood circulation, enhanced tumor accumulation and effective suppression of tumor growth 85 .…”

“…Additionally, coupling siRNA to cell-penetrating peptides reduced the concentration of siRNA required to achieve reduction in tumor size 88 . These cell penetrating-peptide and siRNA payloads have shown to exhibit enhanced antitumor effects in multiple types of cancer in mice including lung, breast and liver cancers [85][86][87][88][89] . Thus, conjugating siRNAs to peptides offer another promising avenue in clinical research for the overall treatment of cancer.…”