VP22-mediated and light-activated delivery of an anti-c-raf1 antisense oligonucleotide improves its activity after intratumoral injection in nude mice

Abstract

VP22, a protein of the herpes simplex virus tegument, can form complexes with fluorescein-labeled oligonucleotides. These particles, termed "Vectosomes," are efficiently taken up by cells and remain stable in the cell cytoplasm without any particular activity. Interestingly, these Vectosomes can be disrupted by light, which releases the antisense activity. Here we show that anti-c-raf1 Vectosomes are efficiently activated by light in vivo after injection into subcutaneous A549 (non-small-cell lung cancer) tumors implanted in nude mice. Moreover, two injections per week of anti-c-raf1 Vectosomes followed by illumination result in a stronger inhibition of tumor growth than injections of the antisense alone or of the different control Vectosomes. This effect correlates with a strong inhibition of the c-Raf1 protein expression. As a consequence of c-Raf1 loss, apoptosis was also detected in these tumors. Vectosomes thus represent a new powerful tool to improve the delivery of oligonucleotides in vitro and in vivo.

Photochemical Internalization: A New Tool for Drug Delivery

“…Upon exposure to light these complexes are relocated in the cells and the ODNs can exert their biological functions, not being observed in the absence of light. This has been documented with anti-c-raf1 vectosomes both in vitro and in vivo [61]. Alternatively, VP22 may be fused with a therapeutically active peptide, such as the proapoptotic BH3 domain of the Bcl-2 family of proteins, mixed with a photoactively labelled ODN and treated with light after it has entered the cells [62].…”

“…VP22 has been non-covalently linked to fluorescein or Bodipy 630/650 oligonucleotides (ODNs) in a ratio forming neutral complexes that might form larger aggregates [61][62][63]. These complexes, named Vectosomes, are taken up in a temperature dependent manner (no uptake at 4 0 C) and locate intracellularly in distinct spots.…”

Targeted pharmaceutical nanocarriers for cancer therapy and imaging

“…Anti-c-Raf1 vectosomes were effi ciently activated by light in vivo after injection into subcutaneous tumors implanted in nude mice and slowed down the tumor growth because of the strong inhibition of c-Raf1 protein expression, the antitumor activity being much higher than that of the antisense alone or of the different control vectosomes. 235 Suicide gene therapy is a widely exploited approach for gene therapy of cancer and other hyperproliferative disorders. However, it is hampered by the relative ineffi ciency of TK gene transfer and its limited bystander effect.…”

Antisense Oligonucleotide-Mediated Splice Switching: Potential Therapeutic Approach for Cancer Mitigation

“…This AO-protein complex is known as a vectosome. This vectosome reaches the cytoplasm and can be triggered by light, which releases the AO and the protein complex [ 220 , 221 , 222 ]. In vivo intravitreal injection of the vectosomes followed by transscleral illumination allowed delivery of AOs to retinal and RPE cells [ 222 ].…”