A Genetic Screen to Identify Gain- and Loss-of-Function Modifications that Enhance T-cell Infiltration into Tumors

Area of Science:

• Immunology
• Oncology
• Genetics

Background:

• T-cell-mediated immunotherapies such as anti-PD-1 and chimeric antigen receptor T cells (CAR-T) are effective against many cancers.
• CAR-T therapy shows success in circulating tumors but limited efficacy in solid tumors due to poor T-cell infiltration.
• Enhancing T-cell trafficking into tumors is a critical strategy to overcome immunotherapy resistance.

Purpose of the Study:

• To identify candidate genes in T cells that promote intratumoral T-cell accumulation using an unbiased genetic screen.
• To discover novel therapeutic targets for enhancing T-cell infiltration into solid tumors.

Main Methods:

• An in vivo genetic screen utilizing the Sleeping Beauty mutagenesis system was performed across three tumor models.
• Candidate genes influencing T-cell accumulation were identified, with analysis considering tumor model and anti-PD-1 treatment.
• The role of the top candidate gene, AAK1, in T-cell trafficking was investigated in vitro and in vivo.

Main Results:

• Over 400 candidate genes were identified, with significant variation based on tumor model and anti-PD-1 treatment status.
• A subset of candidate genes consistently emerged across all tumor models and treatment conditions.
• Inhibition of AAK1, the most frequently mutated gene, modulated chemokine receptor expression and enhanced T-cell trafficking.

Conclusions:

• The study identified numerous candidate genes that can be targeted to improve T-cell infiltration into tumors.
• AAK1 is a promising target for enhancing T-cell trafficking, relevant for improving solid tumor immunotherapy.
• Further validation of these screen candidates is crucial for developing next-generation T-cell therapies for solid tumors.