Chitosan-Based Delivery of Avian Reovirus Fusogenic Protein p10 Gene: In Vitro and In Vivo Studies towards a New Vaccine against Melanoma.

Claudia Robles-Planells,Leonel E Rojo,Eugenio Spencer,Andrea Mella,Silvia Matiacevich,Alejandro Escobar,Claudio Acuña-Castillo,Luis A Milla,Carlos Barrera-Avalos,Brandon A Martínez,Ricardo Fernandez,Juan Pablo Huidobro-Toro,Marcelo Cortez-San Martin,Franco D Navarro,Francisco J Bravo,Jorge Pavez

doi:10.1155/2020/4045760

Claudia Robles-Planells, Leonel E Rojo + Show 14 more

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https://doi.org/10.1155/2020/4045760

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Abstract

Reovirus is known to have an anticancer effect in both the preclinical and clinical assays. Current evidence suggests that the reovirus-mediated impact on tumor growth depends on the activation of specific antitumor immune responses. A feasible explanation for the oncolytic effects and immune system activation is through the expression of the fusogenic reovirus protein. In this work, we evaluated the in vivo antitumor effects of the expression of fusogenic protein p10 of avian reovirus (ARV-p10). We used chitosan nanoparticles (CH-NPs) as a vehicle for the ARV-p10 DNA in murine B16 melanoma models both in vitro and in vivo. We confirmed that ARV-p10 delivery through a chitosan-based formulation (ARV-p10 CH-NPs) was capable of inducing cell fusion in cultured melanoma cells, showing a mild cytotoxic effect. Interestingly, intratumor injection of ARV-p10 CH-NPs delayed tumor growth, without changing lymphoid populations in the tumor tissue and spleen. The injection of chitosan nanoparticles (CH-NPs) also delayed tumor growth, suggesting the nanoparticle itself would attack tumor cells. In conclusion, we proved that in vitro ARV-p10 protein expression using CH-NPs in murine melanoma cells induces a cytotoxic effect associated with its cell fusion. Further studies are necessary for establishing a protocol for efficient in vivo DNA delivery of fusion proteins to produce an antitumoral effect.

Highlights

Virotherapy is an alternative therapy against cancer, which takes advantage of the cytolytic activity of viruses during their infective cycle and the absence of response mechanisms of the tumor cells against viruses
We evaluated the effect of in situ transfection of the avian RV (ARV) FAST protein, named p10, on murine B16 melanoma tumor growth and induction of an immune response using chitosan nanoparticles (CH-NPs) as a vehicle to deliver DNA into cancer cells
In NP-ARVtransfected cells, the syncytium presence was associated with a 20% decrease in B16 cell viability at 120 hours posttransfection (Figure 2(e)). These results show that the transfection of B16 tumor cells using NP-ARV allows the expression of a fusogenically active avian reovirus p10 protein (ARV-p10) protein, which decreases cell viability because of syncytium formation

Summary

Introduction

Virotherapy is an alternative therapy against cancer, which takes advantage of the cytolytic activity of viruses during their infective cycle and the absence of response mechanisms of the tumor cells against viruses. Fusogenic oncolytic viruses (FOVs) show some advantages over nonfusogenic viruses when used against cancer cells, mainly because FOVs can induce tumor immunogenic cell death (ICD), producing cellular structures with strong immune-stimulatory effects [1]. The first virus used against cancer was a modified herpes simplex virus It was aimed at obtaining efficient and safe therapy against unresectable stages of melanoma. This therapy was approved in 2015 by the FDA. The mode of action of these therapies is associated with efficient malignant cell death, mediated by the direct viral cytotoxic effect and/or stimulation of the immune system [5, 6]

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