Oncolytic Vesicular Stomatitis Virus

Vesicular stomatitis virus (VSV), belonging to the family Rhabdoviridaeis, is a non-segmented, negative-strand RNA virus with inherent oncolytic virus qualities which is more susceptible to infect cancer cells that contain antiviral responses induced by type I interferon pathways. To enhance the safety of oncolytic VSV while increasing the capacity for therapeutic transgenes, Creative Biolabs has established a comprehensive platform called OncoVirapy™ to design, engineer and construct the most efficacious recombinant VSV and related products.

Brief Introduction of Oncolytic VSV

VSV is a negative-strand RNA virus with a relatively compact genome (11 kb) containing ~11,000 nucleotides encoding for 5 distinct viral proteins: the nucleocapsid (N) protein, phosphoprotein (P), matrix (M) protein, G protein and large polymerase (L). The negative-sense RNA genome is completely coated in the viral nucleoprotein (N protein) and is transcribed by the viral RNA-dependent RNA polymerase consisting of L and P subunits. L combines with the phosphoprotein to catalyze the replication of the mRNA. Glycoprotein G mediates viral attachment and fusion to host cells by extensively expressed low-density lipoprotein (LDL) receptor. M protein plays a number of vital roles in the infection cycle. It is responsible for the budding of progeny virions, regulation of viral genome replication, and genome packaging.

Fig.1 Vesicular stomatitis virus genome organization.

VSV has been a promising OV candidate for clinical use due to a variety of favorable properties, including its well-studied biology, a small & easily manipulated genome, rapid replication kinetics, inherent tumor specificity and OV qualities, cytoplasmic replication without risk of host-cell transformation, and its potential to elicit a broad range of immunomodulatory responses to break immune tolerance in the tumor microenvironment. Moreover, various VSV-based recombinant viruses have been engineered via reverse genetics to improve oncoselectivity, safety, oncotoxicity and stimulation of tumor-specific immunity.

Oncolytic VSV Engineering

With the advances in DNA recombinant technology, a multitude of strategies has been applied to further improve the immune-stimulating potential of VSV and synergize these responses with the direct oncolytic effect.

• Modification of endogenous VSV genes to stimulate interferon induction

• Virus-mediated expression of cytokines or immune-stimulatory molecules to enhance anti-tumor immune responses

To boost the immune-stimulating potential of an oncolytic VSV, an efficient strategy involves the incorporation of a cytokine or an immune-stimulatory molecule into the viral genome. In the case of VSV, the most common engineering approach is to insert the foreign gene as an additional transcription unit, usually between the endogenous glycoprotein (G) and large polymerase (L) gene.

• Armed oncolytic VSVs

VSV can be armed with suicide gene cassettes that can greatly enhance its tumor-killing properties.

Featured Services and Construction Workflow

We provide a comprehensive range of VSV services based on our advanced OncoVirapy™ platform, including but not limited to the following items:

• GOI cloning (e.g., antibody, bispecific antibody, cytokine, chemokine, shRNA or gRNA) and confirmation through restriction mapping and sequencing verification
• Functional validation of transgenes
• Expression cassette design with the most appropriate promoter to guarantee the high-level expression
• Viral genes engineering (single gene or different genes combination)
• Different construction strategies (homologous recombination, BAC system, etc.)
• VSV amplification, purification, titering services
• VSV whole genome sequencing (WGS) service

Fig.2 Workflow of oncolytic VSV construction at Creative Biolabs.

Creative Biolabs has developed an all-sided OncoVirapy™ platform to offer customized, standardized and high-quality oncolytic VSV construction and engineering services with the expression of different foreign gene cassettes for clients globally, including fluorescent-labeled molecules, suicide genes, cytokines, antibody fragments, etc. Besides, the proof-of-concept validation study (in vitro and in vivo validation study) for the oncolytic virus is also provided. 

References

1. Bishnoi, S.; et al. Oncotargeting by vesicular stomatitis virus (VSV): advances in cancer therapy. Viruses. 2018, 10(2): 90.
2. Marzi, A.; et al. Vesicular stomatitis virus-based vaccines for prophylaxis and treatment of filovirus infections. Journal of bioterrorism & biodefense. 2011 (4).

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