Regulating cytokine function enhances safety and activity of genetic cancer therapies

Area of Science:

• Oncology
• Immunotherapy
• Gene Therapy

Background:

• Systemic genetic therapies, including oncolytic viruses, show promise for cancer treatment.
• Cytokine transgenes are common but can cause toxicity and premature clearance.
• Existing approaches face challenges with delivery, immune activation, and toxicity.

Purpose of the Study:

• To overcome limitations of systemic cytokine delivery in oncolytic viruses.
• To develop a method for controlling transgene function after delivery.
• To enhance both oncolytic and immune-mediated therapeutic effects while reducing toxicity.

Main Methods:

• Systemically delivered oncolytic viruses expressing interleukin (IL)2 or chemokine (CCL5) were evaluated.
• Exogenous regulation was achieved by fusing destabilizing domains to cytokine/chemokine transgenes.
• Therapeutic activity, immune activation, and toxicity were assessed before and after regulation.

Main Results:

• Unregulated IL2 and CCL5 expression reduced oncolytic activity and immune activation, with IL2 increasing toxicity.
• Exogenous regulation allowed an initial phase of enhanced delivery and oncolytic activity without cytokine function.
• Subsequent controlled cytokine function led to enhanced, tumor-targeted immunotherapeutic activity.
• This regulatory strategy significantly improved therapeutic efficacy and reduced toxicity.

Conclusions:

• Exogenous regulation of cytokine/chemokine transgenes overcomes limitations of early expression.
• Controlled transgene function optimizes oncolytic virus delivery, activity, and immunogenicity.
• This approach represents a significant advancement in developing safer and more effective genetic cancer therapies.