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RNA interference is one of the prosperous approaches for cancer treatment. However, small interfering RNA (siRNA) delivery to cancer cells has been faced with various challenges restricting their clinical application over the decades. Since ROR1 is an onco-embryonic gene overexpressed in many malignancies, suppression of ROR1 by siRNA can potentially fight cancer. Herein, a delivery system for ROR1 siRNA based on HIV-1 TAT peptide-capped gold nanoparticles (GNPs) was developed to treat breast cancer. Besides, we introduced a new feasible method for conjugating the peptide to the nanoparticles. Since the GNPs have high affinity to the sulfur, the findings demonstrated the peptide successfully conjugated to the nanoparticles via Au-S bonds. As positively charged nanoparticles showed high cellular uptake, we could use a low concentration of nanoparticles led to high efficient gene transfection with negligible cytotoxicity that was confirmed by flow cytometry, confocal microscopy, gel retardation, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Following transfection, downregulation of ROR1 and its targeted gene, CCND1, induced apoptosis in cancer cells. In conclusion, the reported capped GNPs could be potentially utilized for delivering negatively charged therapeutic agents in particular genes., (© 2019 Wiley Periodicals, Inc.)

Influenza virus causes a highly contagious viral respiratory tract infection with potentially fatal outcomes in humans and animals. There is now widespread influenza virus resistance to commercial drugs due to the genetic diversity of virus. Therefore, new therapeutic formulation needs to be developed. Chitosan/siRNA nanoparticles were generated as a new therapeutic approach against influenza virus infections both in vitro and in vivo. Designed siRNA against influenza nucleoprotein was formulated in chitosan polymer as siRNA/chitosan nanoparticle complex. Particle size and zeta potential of the nanoparticles were measured by dynamic light scattering. The uptake of labeled siRNA into Vero cells was visualized using fluorescence microscopy. Nanoparticle-mediated knockdown of enhanced green fluorescent protein (EGFP) was analyzed and quantified by flow cytometry in Vero cells. Results of the in vitro study showed that chitosan/siRNA nanoparticle was efficiently uptaken by Vero cells, leading to inhibition of influenza virus replication. Furthermore, nasal delivery of siRNA by chitosan nanoparticle complex has antiviral effects and significantly protected BALB/c mice from a lethal influenza challenge. These findings suggest that chitosan nanoparticle equipped with siRNA is a promising system for controlling influenza virus infection.

Small interfering RNA (siRNA) has established its reputation in the field of tissue engineering owing to its ability to silence the proteins that inhibit tissue regeneration. siRNA is capable of regulating cellular behavior during tissue regeneration processes. The concept of using siRNA technology in regenerative medicine derived from its ability to inhibit the expression of target genes involved in defective tissues and the possibility to induce the expression of tissue-inductive factors that improve the tissue regeneration process. To date, siRNA has been used as a suppressive biomolecule in different tissues, such as nervous tissue, bone, cartilage, heart, kidney, and liver. Moreover, various delivery systems have been applied in order to deliver siRNA to the target tissues. This review will provide an in-depth discussion on the development of siRNA and their delivery systems and mechanisms of action in different tissues., (Copyright © 2017 Elsevier B.V. All rights reserved.)