Tanapoxvirus lacking the 15L gene inhibits melanoma cell growth in vitro by inducing interferon-λ1 release

Area of Science:

• Oncolytic virotherapy
• Cancer immunology
• Melanoma research

Background:

• Oncolytic viruses (OVs) are a promising melanoma treatment strategy, inducing tumor cell lysis and immune responses.
• Tanapoxvirus (TPV), a human-compatible virus with a large DNA genome, is a potential candidate for OV development.
• Previous research indicated TPVΔ15L's efficacy in reducing melanoma xenografts.

Purpose of the Study:

• To investigate the immuno-modulatory activities of TPV recombinants, specifically TPVΔ15L.
• To determine the role of interferon-lambda1 (IFN-λ1) in TPVΔ15L-mediated melanoma cell killing.
• To compare the anti-proliferative effects of different interferon types on melanoma cells.

Main Methods:

• Generation of TPV recombinants with specific gene deletions (TPVΔ66R, TPVΔ15L, TPVΔ15LΔ66R).
• Infection of human lung fibroblast WI-38 and melanoma SK-MEL-3 cells with TPVΔ15L.
• Quantification of secreted interferon-lambda1 (IFN-λ1) levels.
• In vitro assessment of anti-proliferative effects of IFN-λ1, IFN-α, and IFN-β on melanoma cells.

Main Results:

• TPVΔ15L infection led to significantly higher secretion of interferon-lambda1 (IFN-λ1) from WI-38 and SK-MEL-3 cells compared to other TPV variants.
• IFN-λ1 demonstrated a more potent anti-proliferative effect on melanoma cells in vitro than IFN-α and IFN-β.
• Evidence suggests TPVΔ15L partially kills melanoma cells through the induction of IFN-λ1.

Conclusions:

• TPVΔ15L exhibits significant immuno-modulatory properties, particularly through the induction of IFN-λ1.
• IFN-λ1 plays a crucial role in the anti-melanoma activity of TPVΔ15L.
• TPVΔ15L warrants further investigation as a potential oncolytic virotherapy agent for melanoma.