Use of endosmolytic peptide derived from influenza virus (IFN-7) for the optimization of small interference RNA nanovehicles for colorectal cancer treatment

GIANNONI F; LLOYD L; CERDA M; MORALES VICENTE; GARAY H; LUKACHER M; SUREK E; ROSI P; POLICASTRO L

Varadero

Simposio; 5th International Symposium on Synthetic Peptide as Human and Veterinary Pharmaceutical Products; 2019

Synthetic Peptides Group, Center for Genetic Engineering and Biotechnology

Colorrectal cancer (CRC) is a leading cause of cancer-related death worldwide. Radio- chemotherapy and immunotherapy are the main approaches for the treatment of this tumor, however these remain poor effective. Gene therapy that consists in the introduction of an exogenous nucleic acid to specific cell population is one of the novel approaches to the development new cancer therapeutic strategies. Among the therapeutic nucleic agents used in this therapy, small interfering RNA (siRNA) is an effective way to silence the expression of specific associated-resistance genes. This molecule have high efficacy at very low concentrations for instance at the picomolar range; however exogenously siRNA that enter to cell though cell membrane should escape of the endosome compartment, where is degraded, to reach successfully the messenger RNA (mRNA) target. In order to overcome this barrier, many endosmolytic peptides or polymers are incorporated into siRNA formulations. IFN-7 is a peptide derived from influenza virus that displays conformational changes for pH variation and produces a disruption of endosmolytic compartment. Previous studies performed in our laboratory demonstrated that the Peroxirredoxin II (PrxII) enzyme, which is overexpressed in CRC, is involved in radio-chemoresistance of tumors. Prx II silencing produces an increase in radio-chemosensitization and a decrease in cell proliferation in vitro and in vivo assays. The main objective of this work is to develop liposomes-based nanovehicles containing a siRNA against PrxII, endosmolytic polymers and the IFN-7 peptide in order to increase siRNA activity in CRC cancer cells. Formulations containing a siRNA against luciferase reporter genes (siRNA-LUC) polyethylenimine (PEI) (endosmolytic polymer) and IFN7 were tested in different PEI/INF-7/siRNA-LUC ratios. Complexes of these three components were encapsulated in liposomes by the hydration film technic. The nanovehicles were characterized measuring their size and mobility in agarose gel. Preliminary experiments were performed in the LoVo CRC cell line with constitutively luciferase gene expression. Thought these experiments we found the ratios of INF-7/PEI/siRNA-Luc with high silencing activity. Finally, liposomes carrying the best molecule ratio formulation were performed changing siRNA-LUC by siRNA-PrxII. Liposoma containing siRNAPrxII/PEI/IFN-7 generated a higher inhibition in cell proliferation respect to liposomes formulated without IFN-7. These results demonstrate that the presence of IFN-7 is a key factor in the optimization of siRNA cell silencing activity and could be an important contribution for the improvement in gene therapy nanovehicles designed.